Skip to main content
Journal of Bone and Mineral Research logoLink to Journal of Bone and Mineral Research
. 2009 Jul 13;25(2):339–355. doi: 10.1359/jbmr.090724

Gene Expression Profiling in Monocytes and SNP Association Suggest the Importance of the Gene for Osteoporosis in Both Chinese and Caucasians

Xiang-Ding Chen 1,2, Peng Xiao 2, Shu-Feng Lei 1, Yao-Zhong Liu 3, Yan-Fang Guo 1, Fei-Yan Deng 1, Li-Jun Tan 1, Xue-Zhen Zhu 1, Fu-Rong Chen 1, Robert R Recker 2, Hong-Wen Deng 1,3
PMCID: PMC3153389  PMID: 19594299

Abstract

Osteoporosis is characterized mainly by low bone mineral density (BMD). Many cytokines and chemokines have been related with bone metabolism. Monocytes in the immune system are important sources of cytokines and chemokines for bone metabolism. However, no study has investigated in vivo expression of a large number of various factors simultaneously in human monocytes underlying osteoporosis. This study explored the in vivo expression pattern of general cytokines, chemokines, and their receptor genes in human monocytes and validated the significant genes by qRT-PCR and genetic association analyses. Expression profilings were performed in monocyte samples from 26 Chinese and 20 Caucasian premenopausal women with discordant BMD. Genome-wide association analysis with BMD variation was conducted in 1000 unrelated Caucasians. We selected 168 cytokines, chemokines, osteoclast-related factors, and their receptor genes for analyses. Significantly, the signal transducer and activator of transcription 1 (STAT1) gene was upregulated in the low versus the high BMD groups in both Chinese and Caucasians. We also revealed a significant association of the STAT1 gene with BMD variation in the 1000 Caucasians. Thus we conclude that the STAT1 gene is important in human circulating monocytes in the etiology of osteoporosis. © 2010 American Society for Bone and Mineral Research.

Keywords: STAT1, bmd, monocytes, osteoporosis, microarray, SNP

Introduction

Osteoporosis is mainly characterized by low bone mineral density (BMD). Genetic factors have important influences on BMD and osteoporosis.(13) Recent studies have shown that the immune system is strongly related to bone metabolism in terms of osteoimmunology.(48) Pathologic bone resorption was observed in immune system–related diseases such as autoimmune arthritis, periodontitis, Paget's disease, and bone tumors.(9)

Monocytes, important cells in immune system, produce a wide variety of factors such as interleukin 1 (IL-1), IL-6, tumor necrosis factor (TNF), transforming growth fator beta (TGF-β), and 1,25-dihydroxyvitamin D3 [1,25(OH)2D3].(10) These factors are involved in bone metabolism by regulating osteoclastic differentiation. Monocytes are also potential precursors of osteoclasts.(11,12) In vitro studies demonstrated that monocytes can differentiate into osteoclasts with bone resorption function.(13,14)

However, it is unknown whether other factors and mechanisms to regulate these factors are important in the ability of monocytes to affect bone metabolism. To address these questions, scientists have screened the differential gene expressions in osteoclastogenic cells using a high-throughput microarray platform.(15,16) Microarray technology has been used successfully for detection of gene expression profiles in diseases such as inflammatory breast cancer and urinary bladder cancer.(17,18) Theoretical studies also supported the reliability of using a microarray platform for the quantitative characterization of gene expression.(19,20) However, differential gene expression profiles in circulating monocytes associated with BMD variation had not been investigated until our previous research in Caucasian females.(16) In that study, we showed that chemokine receptor 3 (CCR3), histidine decarboxylase (HDC), and glucocorticoid receptor (GCR) genes in circulating monocytes potentially contributed to bone metabolism.(16)

The present study aims to identify significantly differentially expressed genes from 168 selected cytokine, chemokine, and osteoclastogenesis-related genes in circulating monocytes between the high and low BMD groups in Chinese Han females and validate the significant expression in Caucasian women. We also performed single-nucleotide polymorphism (SNP) association analysis with BMD to find further evidence of the identified genes at the DNA level.

Materials and Methods

Chinese subjects

The study was approved by the Research Administration Department of Hunan Normal University. Eight hundred and seventy-eight females who were Chinese Hans were recruited from Changsha City. All subjects signed informed-consent documents before entering the project. Healthy female subjects aged of 20 to 45 years were included because BMD reaches its peak and is most stable during this period. For each subject, we collected information on age, sex, medical history, family history, menstrual history, smoking history, physical activity, alcohol use, tea and coffee consumption, diet habits, etc. Female subjects must have regular menses to avoid the effects of menopause on BMD. Subjects with chronic diseases and conditions that potentially may affect bone mass have been excluded from the study. These diseases/conditions included chronic disorders involving vital organs (e.g., heart, lung, liver, kidney, and brain), serious metabolic diseases (e.g., diabetes, hypo- and hyperparathyroidism, and hyperthyroidism, etc.), skeletal diseases (e.g., Paget's disease, osteogenesis imperfecta, and rheumatoid arthritis, etc.), chronic use of drugs affecting bone metabolism (e.g., corticosteroid therapy and anticonvulsant drugs), and malnutrition conditions (e.g., chronic diarrhea, chronic ulcerative colitis, etc.). From the 100 top and 100 bottom hip BMD subjects we recruited all who consented to enter our potential future projects, including 14 high hip BMD (mean ± SD = 1.03 ± 0.05 g/cm2) subjects and 12 low hip BMD (mean ± SD = 0.7 ± 0.06 g/cm2) subjects (Table 1). Thirty milliliters of peripheral blood were drawn for each selected subject.

Table 1.

Basic Characteristic Description of the Study Subjects in Chinese and Caucasians

Female Chinese for gene expression Female Caucasians for gene expression Male Caucasians for SNP association Female Caucasians for SNP association




Trait Low BMD(n = 12) High BMD (n = 14) Low BMD (n = 10) High BMD (n = 10) ≤50 years (n = 250) >50 years (n = 251) Premenopausal (n = 249) Postmenopausal (n = 250)
Age years 25.28 ± 3.14 28.67 ± 4.72 42.90 ± 1.91 41.70 ± 1.89 33.44 ± 9.66 67.33 ± 6.74 33.97 ± 8.45 66.36 ± 5.67
Height (cm) 158.88 ± 4.36 158.93 ± 5.28 160.46 ± 5.01 166.96 ± 7.30 180.00 ± 6.78 175.67 ± 6.63 165.38 ± 6.13 162.22 ± 6.43
Weight (kg) 51.54 ± 7.31 55.84 ± 5.73 58.00 ± 7.53 91.64 ± 19.58 88.03 ± 15.35 90.04 ± 14.47 70.74 ± 16.51 71.71 ± 5.10
Spine BMD (g/cm2) 0.85 ± 0.07 1.04 ± 0.09 0.90 ± 0.08 1.21 ± 0.08 1.05 ± 0.12 1.08 ± 0.20 1.05 ± 0.11 0.94 ± 0.10
Hip BMD (g/cm2) 0.70 ± 0.06 1.03 ± 0.05 0.79 ± 0.08 1.14 ± 0.09 1.07 ± 0.15 1.01 ± 0.14 0.95 ± 0.12 0.86 ± 0.14

Note: Values are the mean ± SD.

BMD measurement

BMD (g/cm2) at the lumbar spine (L1–4, anteroposterior view) and total hip (femoral neck, trochanter, and intertrochanter region) was measured by a Hologic 4500-W dual-energy X-ray absorptiometry (DXA) (Hologic Corp., Waltham, MA, USA). The DXA scanner was calibrated daily, and long-term precision was monitored with external spine and hip phantoms. The coefficient of variation (CV) of measured BMD values was 0.80% at the hip.

Monocyte isolation

A monocyte negative isolation kit (Dynal Biotech, Inc., Lake Success, NY, USA) was used to isolate circulating monocytes from 30 mL of whole blood following the procedures recommended by the manufacturer. The kit contains a mixture of antibodies for CD2, CD7, CD16, CD19, CD56, and CD235a to deplete T cells, B cells, natural killer cells, erythrocytes, and granulocytes (if present), leaving monocytes untouched, pure, viable, and free of the surface-bound antibody and beads. Monocyte purity was assessed by flow cytometry (BD Biosciences, San Jose, CA, USA) with fluorescence-labeled antibodies PE-CD14 and FITC-CD45. The purity was 86% on average (Fig. 1).

Fig. 1.

Fig. 1

Flow cytometer analysis of the percentage of CD14+/CD45+ cells from human blood. CD14 and CD45 are the specific membrane markers on monocytes and mononuclear cells, respectively.

Total RNA extraction and microarray procedure

Total RNA from monocytes was extracted using a Qiagen RNeasy Mini Kit (Qiagen, Inc., Valencia, CA, USA). RNA integrity was assessed by using an Agilent 2100 Bioanalyzer (Agilent Technologies, Palo Alto, CA, USA). A total of 10 µg RNA from each sample was converted into biotinylated fragmented cRNA (BioArray HighYield RNA Transcription Labeling Kit, Enzo Diagnostics) that was hybridized (Affymetrix Genechip Hybridization Oven 640) to HG-U133 plus 2.0 GeneChip oligonucleotide arrays (Affymetrix, Santa Clara, CA, USA), which contains 54,675 sets of oligonucleotide probes that correspond to approximately 38,500 unique human genes, and then washed (Affymetrix Fluidics Station 450), stained with phycoerythrin-streptavidin, and scanned using Affymetrix Gene Array Scanner 3000.

Statistical analysis

Transciptome-wide expression profiling involves a large number of genes and thus incorporates tremendous multiple tests. Some genes with suggestive significance may be excluded after the multiple-testing correction. If some genes are tightly related in a functionally relevant pathway, the P value for any single gene may not be significant after the multiple-testing correction. However, a focused expression screen on potential functional relevant genes largely can reduce the multiple tests and may increase the statistical power. Considering the multicomparison problem and the function of monocytes, 168 candidate genes were selected for statistical analyses. The 168 genes are all available cytokines, chemokines, osteoclast-related factors, and their receptors selected for our focused expression analyses of the Affymetrix HG133 plus 2.0 gene data set (see Appendix table). Microarray Suite 5.0 (MAS 5.0, Affymetrix) software was used to generate the array raw data files (CEL files). Then the probe-level data in CEL files were converted into expression measures and normalized by the robust multiarray average algorithm (RMA, http://www.bioconductor.org).(21) The differential expression analysis between low and high BMD samples was conducted by a nonparameter Wilcoxon signed-rank test. A Benjamini and Hochberg (BH) stepwise procedure was used for multiple-comparison adjustment,(22) and an adjusted P ≤ .05 was used as the significant criterion. Fisher's exact test was used in the canonical pathway analysis by Ingenuity Pathways Analysis (IPA) software (Ingenuity Systems, http://www.ingenuity.com) to test the association between genes within a canonical pathway and BMD variation. According to the similarity of gene expression, the differentially expressed genes were further analyzed for two-dimensional hierarchical clustering at both gene and sample levels.(23)

Array replication in Caucasians

In this independent microarray study, we recruited 20 premenopausal Caucasian women, 10 with high BMD (spine or hip Z-score greater than +0.84) and 10 with low BMD (spine or hip Z-score less than −0.84; see Table 1) from the vicinity of Creighton University in Omaha, Nebraska, USA, for differential expression analyses in their circulating monocytes. Although the weights in the high BMD group were higher than in the low BMD group, no significant correlation of BMD with weight was detected in the low or high BMD group. This study was approved by the Institutional Review Board, and all the subjects signed informed-consent documents before entering the project. The inclusion and exclusion criteria were the same as in the Chinese population, but the age criterion was limited to the narrow range of 39 to 45 years, within the peak BMD range of 20 to 45 years. For the Caucasian samples, we used the Affymetrix HG-133A instead of the HG-U133 plus 2.0 that we used for the Chinese samples (the HG-133A chip contains fewer genes than the HG-U133 plus 2.0), but all the other experimental procedures and statistical analyses were the same as we described for Chinese samples.

Validation by qRT-PCR in Caucasians

We used two-step qRT-PCR to confirm differentially expressed genes. Reverse-transcription reactions were performed in a 50 µL reaction volume containing 5 µL 10× PCR Buffer II, 11 µL 25 mM MgCl2, 10 µL dNTPs, 1.25 µL MULV reverse transcriptase, 1.0 µL RNase inhibitor, 2.5 µL Oligo d(T), 0.5 µg total RNA, and water to 50 µL. All these reagents were supplied by Applied Biosystems (Foster City, CA, USA). Reaction conditions were as follows: 10 minutes at 25°C, 30 minutes at 48°C, and 5 minutes at 95°C. Real-time quantitative PCR was performed in a 25 µL reaction volume using standard protocols on an Applied Biosystems 7900HT. Briefly, 2.5 µL of cDNA was mixed with 12.5 µL of TaqMan universal PCR master mix (2×), 1.25 µL of TaqMan gene express assay mix (contains forward and reverse primers and labeled probe), 1.25 µL of human GAPDH probe (20×), and 7.5 µL of water. The thermocycling conditions were as follows: 2 minutes at 50°C, 10 minutes at 95°C, and 40 cycles of 15 seconds at 95 °C plus 1 minute at 60°C. Based on the relative gene expression 2−ΔΔCt,(16) we performed Student's t test to confirm the differential expression genes. All reactions were run in triplicates for each gene.

Confirmation of significant genes in SNP association study

Subjects and phenotype

For the association study, 1000 unrelated Caucasian subjects were identified from our established and expanding genetic repertoire, currently containing more than 6000 subjects. All subjects were U.S. Caucasians of European origin. The inclusion and exclusion criteria were the same as in the Chinese population for expression study, but males and postmenopausal women were included. The basic characteristics of all subjects are listed in Table 1. BMD values at spine and hip were measured using the Hologic 4500A DXA (Hologic, Inc., Bedford, MA, USA). The coefficient of variation of the DXA measurement was approximately 1.98% for spine BMD and 1.87% for hip BMD.

Genotyping and statistical analysis

Genomic DNA was extracted from whole human blood using a commercial isolation kit (Gentra Systems, Minneapolis, MN, USA). Genotyping with the Affymetrix Mapping 250K Nsp and 250K Sty arrays was performed. Fluorescence intensities were quantified using an Affymetrix Array Scanner 30007G. Data management and analyses were performed using the Affymetrix GeneChip Operating System. The final average Bayesian Robust Linear Model with Mahalanobis (BRLMM) call rate across the entire sample reached the high level of 99.14%. We tested the association of significant genes identified in the expression studies with BMD in the 1000 Caucasian subjects. Parameters such as age, age2, sex, age/age2-by-sex interaction, height, and weight were tested for their association with BMD at spine and hip. The significant (P ≤ .05) terms then were included as covariates to adjust the raw BMD values for subsequent analyses. Statistical analyses were performed using genotype and haplotype association software implemented in PLINK-1.03 (http://pngu.mgh.harvard.edu/purcell/plink/).(24) Linkage disequilibrium (LD) patterns were analyzed and plotted with the correlation coefficient between pairs of loci based on the 1000 unrelated Caucasians using the the Haploview program (http://www.broad.mit.edu/mpg/haploview/),(25) which describes more or less combinations of alleles. The haplotype block was used to show chromosome regions with high LD and low haplotype diversity in haplotpye association studies. MAPPER was used for searching transcript factor binding sites in the JASPAR database (http://mapper.chip.org/).(26)

Results

The basic characteristics of the study subjects are shown in Table 1. Although hip BMD is the major study phenotype for the expression analyses in Chinese, spine BMD also was significantly different between the high and low BMD groups (P = 1.49 × 10−6). There were no significant differences in age and height traits between the high and low BMD groups for both Chinese and Caucasians for expression analyses. However, the weight and body mass index (BMI, kg/m2) in the low BMD group were significantly lower than in the high BMD group in Caucasians. We performed a general linear regression analyses for STAT1 expression values and BMD status and incorporated weight and height as covariates in Caucasians. However, weight and height are not significant as covariates for STAT1 expression analysis in the high and low BMD groups (P = .2529 and .2045, respectively). This implied that the weight and height in current study were not confounding factors for BMD in our expression analyses.

All the nominally significant genes (P < .05) of differential expression with BMD in Chinese are summarized in Table 2. We submitted our gene expression profiling to the Gene Expression Omnibus (http://www.ncbi.nlm.nih.gov/geo/), and the access number was GSE7158. After Benjamini and Hochberg correction for multiple comparisons, the differential expressions of signal transducer and activator of transcription 1 (STAT1) (adjusted P = .02248) and guanylate binding protein 1 (GBP1) (adjusted P = .03372) genes were still significant between the low and the high BMD groups. Expression fold changes of the significant genes were not large in the present study. The main reason might be that the female subjects in this study all were 20 to 45 years of age and with regular menses, in contrast with including both premenopausal and postmenopausal women in our previous study.(16) Actually, a 1.5-fold change has been shown to be significant in other differential gene expression studies.(2730) In addition, BMD is a complex trait, and genes regulating its variation are not expected to have large differential expressions. In Fig. 2, a two-dimensional hierarchical dendrogram (based on the nominally significant genes listed in Table 2) shows the results of the hierarchical clustering analyses. Low BMD subjects were mainly clustered to the bottom of the figure.

Table 2.

Differential Expression of Cytokine, Chemokines, and Osteoclastogenesis-Related Genes in Blood Monocytes From the Low and the High BMD Groups in Chinese

Probe ID Gene symbol Gene title L-BMD intensity H-BMD intensity Fold L/H Raw P value Adjusted P value
200887_s_at STAT1 Signal transducer and activator of transcription 1 857.21 582.34 1.47 .00008 .02248*
202269_x_at GBP1 Guanylate binding protein 1 401.11 245.99 1.63 .00024 .03372*
204533_at CXCL10 Chemokine (C-X-C motif) ligand 10 162.43 83.22 1.95 .00155 .062623
205992_s_at IL15 Interleukin 15 234.54 174.21 1.35 .00310 .096789
214453_s_at IFI44 Interferon-induced protein 44 321.75 186.31 1.73 .00693 .13910
225636_at STAT2 Signal transducer and activator of transcription 2 404.73 339.6 1.19 .00937 .14628
202688_at TNFSF10 Tumor necrosis factor (ligand) superfamily member 10 1094.65 889.05 1.23 .01084 .16032
204439_at IFI44L Interferon-induced protein44-like 424.81 153.59 2.77 .01261 .16106
242907_at GBP2 Guanylate binding protein 2 335.3 214.65 1.56 .01677 .18849
209417_s_at IFI35 Interferon-induced protein 35 158.99 115.84 1.37 .02209 .23874
201642_at IFNGR2 Interferon gamma receptor 2 831.32 811.55 1.02 .02882 .27926
212657_s_at IL1RN Interleukin 1 receptor antagonist 468.82 256.04 1.83 .03721 .30425
226757_at IFIT2 Interferon-induced protein with tetratricopeptide epeats 2 292.64 205.9 1.42 .03721 .30425

Note: Hybridization intensity and “present” status were given based on MAS5 algorithm. L-BMD intensity means hybridization intensity from the low BMD group; H-BMD intensity means hybridization intensity from the high BMD group. Fold L/H means the ratio of hybridization intensity from the low to that from the high BMD group. Raw P value means P value before multiple testing corrections. Adjusted P value represents P value adjusted with Benjamini/Hochberg method, and asterisks * means significant after Benjamini-Hochberg correction considering 281 probes of selected genes.

Fig. 2.

Fig. 2

Two-dimensional hierarchical dendrograms clustered both the rows and columns of the data, the vertical axis showing the clustering of the subjects with different BMD (“L” for the low BMD and “H” for the high BMD) and the horizontal axis showing the clustering of the intensity of different gene expressions.

Many genes in interferon (IFN) pathway were differentially expressed. STAT1, GBP1, interferon gamma receptor 2 (IFNGR2), signal transducer and activator of transcription 2 (STAT2), guanylate binding protein 2 (GPB2), chemokine (C-X-C motif) ligand 10 (CXCL10), interferon-induced protein 44 (IFI44), interferon-induced protein 44-like (IFI44L), tumor necrosis factor (ligand) superfamily member 10 (TNFSF10), interferon-induced protein 35 (IFI35), and interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) genes had higher expression in the low BMD group. Furthermore, the canonical pathway analysis supported the importance of interferon signaling pathway mediated by the STAT1 gene in determining BMD variation (P = 1.67 × 10−9).

In the interleukin system, interleukin 1 receptor antagonist (IL1RN) and interleukin 15 (IL15) genes were upregulated in the low BMD group compared with the high BMD group. However, IL6 gene expression was not detected.

Interestingly, the differential expression of the STAT1 gene in circulating monocytes was replicated in our ongoing comparison microarray study between the low and high BMD premenopausal Caucasian women. Consistently, upregulation of the STAT1 gene in the low BMD group also was significant after Benjamini and Hochberg correction for multiple testing (P = .0028, adjusted P = .048) (Table 3). qRT-PCR confirmed the significant differential expression of the STAT1 gene in Caucasians (P = .0046) (see Table 3). For the GBP1 gene, we did not find any significant results in both array and qRT-PCR analyses in Caucasians.

Table 3.

Microarray and qRT-PCR Results for the Expression of STAT1 Gene in Circulating Monocytes Between the Low and High BMD Groups in Chinese and in Caucasians

Population Strategy Expression value in low BMD Expression value in high BMD Fold change (L/H) P value
Chinese Affymetrix Microarray HG-U133 Plus 2.0 857.21 ± 292.94 582.34 ± 145.46 1.47 .02248*
Caucasians Affymetrix Microarray HG-133A 957.18 ± 361.28 575.67 ± 243.00 1.66 .048*
Caucasians qRT-PCR 3.13 ± 0.84 1.93 ± 0.75 1.62 .0046

Note: Expression value of Affymetrix Microarray was the hybridization intensity based on the MAS5 algorithm; expression value of qRT-PCR was relative quantity based on 2−ΔΔCt; fold L/H means the ratio of gene expression from the low to that from the high BMD group; * indicates the BH-adjusted P values for multiple testing.

In SNP genotyping analysis using an additive model, two SNPs, rs10199181 (P = .0028) and rs2030171 (P = .0264), in the STAT1 gene were associated with spine BMD (Table 4). It was obvious that subjects with the T allele of rs10199181 possessed high spine BMD (Fig. 3). Figure 4 shows the correlation coefficient between pairs of SNPs of the STAT1 gene and reconstructed haplotype blocks. Interestingly, rs10199181 and rs2030171 were located in the same block, and a haplotype composed of SNPs rs16833157-rs2030171-rs10199181 (“G-G-A”) in the block also was demonstrated to be significantly associated with spine BMD (P = .0029). However, no significant association was detected for 14 SNPs in GBP1 with BMD in Caucasians.

Table 4.

Results for Eight SNP Association Analyses of the STAT1 Gene for Hip and Spine BMD in Caucasians

SNP name SNP ID Position Function Allelea P HWEb MAFc MAFd P value (hip BMD) P value (spine BMD)
SNP_A-1830221 rs6718902 191546449 Intron 24 A/G 0.7202 0.237 0.229 .1171 .2828
SNP_A-1966285 rs1914408 191548221 Intron 23 A/G 1 0.235 0.225 .1103 .2447
SNP_A-4228696 rs34997637 191567075 Intron 10 G/A 0.6512 0.234 0.250 .7317 .0895
SNP_A-2224968 rs16833157 191570643 Intron 9 A/G 0.3554 0.056 0.034 .5069 .0672
SNP_A-1966287 rs41379347 191577187 Intron 5 G/A 1 0.008 0.025 N/A N/A
SNP_A-1966288 rs2030171 191577408 Intron 5 A/G 0.6562 0.321 0.300 .5866 .0264
SNP_A-4257270 rs10199181 191581798 Intron 4 T/A 0.7278 0.368 0.342 .2602 .0028
SNP_A-1783099 rs10208033 191587662 5' near gene G/A 0.6373 0.400 0.450 .8659 .5721

N/A = The locus was not calculated for the significant test because of minor allele frequency of < 0.05.

a

The former allele represents the minor allele of each locus.

b

P value for Hardy-Weinberg equilibrium test.

c

Minor allele frequency calculated in our Caucasian sample.

d

Minor allele frequency reported for Caucasians in the public database of HapMap CEU.

Fig. 3.

Fig. 3

BMD (mean ± SE) in different genotypes of rs10199181 in the STAT1 gene in Caucasians.

Fig. 4.

Fig. 4

Pairwise linkage disequilibrium pattern of eight SNPs in the STAT1 gene in 1000 unrelated Caucasians. Numbers in the squares are 100 by correlation coefficients (100r2) between pairs of SNPs. The intensity of shading is proportional to r2. SNP IDs in bold represent tag SNPs. Numbers in parentheses indicate lengths of haplotype blocks.

Discussion

In this study we investigated expression of 168 genes related to cytokines, chemokines, osteoclast formation factors, and corresponding receptors in monocytes from Chinese Han women with extremely discordant BMD. Thirteen genes were found to be differentially expressed. A very interesting phenomenon was that among the 13 genes, the STAT1, IFI44L, CXCL10, IFI44, GPB1, and GPB2 genes were expressed in higher levels in the low BMD group than in the high BMD group, which is very similar to the IFN-induced gene expression pattern (IFN pathway). For instance, immature peripheral blood mononuclear phagocytes stimulated by the type I IFN isoform increased the expression of 44 genes, including STAT1, IFI44L, CXCL10, IFI44, GPB1, and GPB2.(31) Microarray analysis of cells infected with short hairpin RNA vectors pAB319 and pAB322 showed enhanced expression of many IFN target genes, such as STAT1, IFI44L, CXCL10, IFI44, and GPB1.(32) The increased expression of IFN pathway genes also was detected in blood mononuclear cells from patients with systemic lupus erythematosus and juvenile dermatomyositis(33) and in the human fibrosarcoma cell line.(34) The IFN pathway may regulate bone resorption in two ways. First, interferon-γ (IFNG) blocks RANKL-induced osteoclast differentiation.(9,35) Second, the IFN pathway in circulating monocytes may stimulate the secretion of cytokines IL-1, IL-6, and TNF to increase bone resorption.(3638) In this study, the upregulation of STAT1-mediated IFN pathway genes in the low BMD group suggested the important effect of STAT1 on bone resorption in vivo in humans.

For the 13 differentially expressed genes, however, only the STAT1 and GBP1 genes remained significant after correction for multiple testing. In our previous genome-wide array study on the same Chinese samples, we also found significant differential expression of the STAT1 and GBP1 genes in the array data analyses after correcting for multiple testing.(39) However, further qRT-PCR only confirmed the significance of the GBP1 gene but not the STAT1 gene.(39) Thus we tried to replicate significance of the two genes in our Caucasian expression study on circulating monocytes from 20 premenopausal Caucasian women (10 with low BMD and 10 with high BMD) and SNP association study on 1000 unrelated Caucasian subjects. We did not find the significance of the GPBP1 gene in either replication study. Interestingly, however, the significance of the STAT1 gene was found in both replication studies. In particular, significant upregulation of the STAT1 gene was found in both array and qRT-PCR experiments in the Caucasian expression study. The STAT1 gene was not differentially expressed in B cells isolated from peripheral blood between the high and low BMD subjects (data not shown) who were the same Caucasians for our current monocyte study. Therefore, it is likely that the alterations in STAT1 expression only in monocytes, but not in other cells, are responsible for variations in bone mass in humans.

In the IFN signaling pathway, STAT1 is a critical mediator gene.(9,40) In the above-mentioned IFN pathway for regulating bone resorption, STAT1 mediates the effects of IFNG on both inhibition of RANKL-induced osteoclast differentiation(9,35,41) and secretion of IL-1, IL-6, and TNF.(3638) In addition, in dexamethasone-treated peripheral blood mononuclear cell (PBMC) cultures, the inhibited IFNG expression suppressed expression of the STAT1 gene.(42) Furthermore, in lupus nephritis patients, basal expression of STAT1 was significantly higher in monocytes. and stimulation of the monocyte cultures with IFNG resulted in phosphorylation of STAT1.(43)

In mice, the STAT1 gene plays an important role in bone metabolism in osteoblasts.(44) Recently, STAT1 was reported to be upregulated in femur tissue in osteoporotic mice,(45) and this supports our finding of the high expression of STAT1 in monocytes in human low BMD groups.

Interestingly, our published linkage study of BMD in 4126 human subjects also identified suggestive univariate and significant epistatic linkage signals at 2q32, which harbors the STAT1 gene.(46) Furthermore, our group recently found significant linkage evidence on 2q32 with spine BMD using bivariate linkage analysis.(47) Our current SNP association study also replicated the significance of the STAT1 gene for spine BMD in Caucasian samples. No SNP in the STAT1 gene was associated with hip BMD at the SNP level, perhaps owing to different genetic determinants for spine BMD and hip BMD traits because many studies have shown different heritability and genetic loci underlying the two traits.(47,48) Hence our results tend to reveal the significance of STAT1 on spine BMD. Subjects with the T allele of SNP rs10199181 in the STAT1 gene tended to have a higher spine BMD than those with other alleles (see Fig. 3). According to the transcript factor Jaspar database, the T allele of rs10199181 is likely to bind transcript factor E4BP4, which might be induced by parathyroid hormone (PTH), a well-know hormone for bone growth, in osteoblasts.(49,50) The inducible effect of E4BP4 suggests a negative regulation by glucocorticoids that might decrease BMD.(51) Thus it implies that the T allele of rs10199181 in the STAT1 gene may be involved in bone growth metabolism.

Based on the present results and previous knowledge, we developed a novel mechanism for osteoclastogenesis (Fig. 5). In peripheral blood, IFN mediated by STAT1 may stimulate circulating monocytes to produce cytokines such as IL-1, TNF, CXCL10, and IL-15 that increase the bone resorption function of osteoclasts. Another pathway in the bone microenvironment also may be triggered by upregulated STAT1 and IFN, which may inhibit osteoblatogenesis. In this study, no expression of the RANK and TRAF6 genes in circulating monocytes was detected, suggesting that osteoclast formation was completely inhibited in circulating monocytes. The fact that osteoclast differentiation was not initiated in peripheral circulating monocytes in both the high and low BMD groups is possibly because osteoclast formation from monocytes may occur only in a special microenvironment.(52)

Fig. 5.

Fig. 5

Diagram of the osteoclastogenesis mechanism. The novel pathway mediated by STAT1 in blood monocytes was connected by big hollow arrows. The solid arrows indicate activation, and the dashed arrows indicate inhibition.

Our current research studied and found the importance of only the STAT1 gene in the function of monocytes or osteoclasts on bone metabolism, which, however, did not address the reported importance of the STAT1 gene in osteoblasts.(9,44)

In summary, our results support the fact that the STAT1 gene in circulating monocytes plays important roles in bone metabolism and also suggests that gene expression of the STAT1-mediated IFN pathway may be important for osteoporosis.

Acknowledgments

This study was partially supported by grants from Natural Science Foundation of China (30771222, 30731160618, 30230210, and 30600364) and the Scientific Research Fund of the Hunan Provincial Education Department (04B039, 05B037). HWD was partially supported by grants from the National Institutes of Health (R01 AR050496, K01 AR02170, R01 AR45349, GM60402, R21 AG027110, R21 AA015973, R01 AG026564, and P50 AR055081) and the Dickson/Missouri endowment. This study also was partially supported by grants from the Sate of Nebraska (LB595 and LB692). Both XDC and PX contributed equally to this work.

Appendix Table

Expression of 168 genes (281 probes) Related to Cytokine, Chemokine, and Osteoclastogenesis-Related Genes in Blood Monocytes From the Low and High BMD Groups

Probe ID Gene symbol Gene title L-BMD intensity H-BMD intensity Fold L/H Raw P value Adjusted P value
200887_s_at STAT1 Signal transducer and activator of transcription 1, 91 kDa 857.21 582.34 1.47 0.00008 0.02248*
202269_x_at GBP1 Guanylate binding protein 1, interferon-inducible, 67 kDa, guanylate binding protein 1, interferon-inducible, 67 kDa 401.11 245.99 1.63 0.00024 0.03372*
209969_s_at STAT1 Signal transducer and activator of transcription 1, 91 kDa 181.82 99.56 1.83 0.00043 0.04027*
231577_s_at GBP1 Guanylate binding protein 1, interferon-inducible, 67 kDa 680 363.24 1.87 0.00075 0.052687
207375_s_at IL15RA Interleukin 15 receptor, alpha 94.78 82.73 1.15 0.00156 0.062623
204533_at CXCL10 chemokine (C-X-C motif) ligand 10 162.43 83.22 1.95 0.00155 0.062623
204533_at CXCL10 Chemokine (C-X-C motif) ligand 10 162.43 83.22 1.95 0.00155 0.062623
202270_at GBP1 Guanylate binding protein 1, interferon-inducible, 67 kDa, guanylate binding protein 1, interferon-inducible, 67 kDa 518.93 288 1.8 0.00221 0.077626
205992_s_at IL15 Interleukin 15 234.54 174.21 1.35 0.0031 0.096789
216598_s_at CCL2 Chemokine (C-C motif) ligand 2 16.08 8.82 1.82 0.00396 0.11128
222484_s_at CXCL14 Chemokine (C-X-C motif) ligand 14 2.68 3.6 0.75 0.00503 0.12849
217371_s_at IL15 Interleukin 15 114.54 88.29 1.3 0.00693 0.1391
214453_s_at IFI44 Interferon-induced protein 44 321.75 186.31 1.73 0.00693 0.1391
1560791_at CXCL9 Chemokine (C-X-C motif) ligand 9 8.51 8.08 1.05 0.00692 0.1391
217502_at IFIT2 Interferon-induced protein with tetratricopeptide repeats 2 104.43 75.69 1.38 0.00746 0.13975
207902_at IL5RA Interleukin 5 receptor, alpha 22.33 19.24 1.16 0.00861 0.14628
236897_at IL17RB Interleukin 17 receptor, beta 3.45 5.03 0.69 0.00933 0.14628
225636_at STAT2 Signal transducer and activator of transcription 2, 113 kDa 404.73 339.6 1.19 0.00937 0.14628
202688_at TNFSF10 Tumor necrosis factor (ligand) superfamily, member 10, tumor necrosis factor (ligand) superfamily, member 10 1094.65 889.05 1.23 0.01084 0.16032
1560999_a_at IL12RB2 Interleukin 12 receptor, beta 2 7.89 7.96 0.99 0.01247 0.16106
204439_at IFI44L Interferon-induced protein 44-like 424.81 153.59 2.77 0.01261 0.16106
205599_at TRAF1 TNF receptor-associated factor 1 20.8 23.99 0.87 0.01168 0.16106
202748_at GBP2 Guanylate binding protein 2, interferon-inducible, guanylate binding protein 2, interferon-inducible 307.78 240.71 1.28 0.01354 0.16542
227264_at TRAF6 TNF receptor-associated factor 6 31.43 31.59 0.99 0.01545 0.18089
242907_at GBP2 Guanylate binding protein 2, interferon-inducible 335.3 214.65 1.56 0.01677 0.18849
209417_s_at IFI35 Interferon-induced protein 35 158.99 115.84 1.37 0.02209 0.23874
204747_at IFIT3 Interferon-induced protein with tetratricopeptide repeats 3 162.68 103.01 1.58 0.0236 0.24561
201642_at IFNGR2 Interferon gamma receptor 2 (interferon gamma transducer 1) 831.32 811.55 1.02 0.02882 0.27926
214038_at CCL8 Chemokine (C-C motif) ligand 8 34.53 23.4 1.48 0.02868 0.27926
212657_s_at IL1RN Interleukin 1 receptor antagonist 468.82 256.04 1.83 0.03721 0.30425
211517_s_at IL5RA Interleukin 5 receptor, alpha 18.71 19.07 0.98 0.03265 0.30425
204863_s_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 80.19 57.06 1.41 0.04215 0.30425
206693_at IL7 Interleukin 7 28.73 32.91 0.87 0.03724 0.30425
206618_at IL18R1 Interleukin 18 receptor 1 11.01 21.06 0.52 0.04753 0.30425
221658_s_at IL21R Interleukin 21 receptor 11.34 13.19 0.86 0.03918 0.30425
237493_at IL22RA2 Interleukin 22 receptor, alpha 2 10.52 14.41 0.73 0.04177 0.30425
1552912_a_at IL23R Interleukin 23 receptor 5.7 5.07 1.12 0.04464 0.30425
206569_at IL24 Interleukin 24 16.97 15.76 1.08 0.04745 0.30425
207964_x_at IFNA4 Interferon, alpha 4 15.55 6.72 2.31 0.04468 0.30425
232375_at STAT1 Signal transducer and activator of transcription 1, 91 kDa 142.43 89.1 1.6 0.04764 0.30425
226757_at IFIT2 Interferon-induced protein with tetratricopeptide repeats 2 292.64 205.9 1.42 0.03721 0.30425
231578_at GBP1 Guanylate binding protein 1, interferon-inducible, 67 kDa 20.83 15.71 1.33 0.04753 0.30425
210390_s_at CCL14, CCL15 Chemokine (C-C motif) ligand 14, chemokine (C-C motif) ligand 15 2.8 2.81 0.99 0.04764 0.30425
210549_s_at CCL23 Chemokine (C-C motif) ligand 23 9.67 14.94 0.65 0.03958 0.30425
206172_at IL13RA2 Interleukin 13 receptor, alpha 2 3.4 3.84 0.89 0.05017 0.30837
229263_at IL17RD Interleukin 17 receptor D 6.23 5.42 1.15 0.05048 0.30837
207160_at IL12A Interleukin 12A (natural killer cell stimulatory factor 1, cytotoxic lymphocyte maturation factor 1, p35) 4.14 4.3 0.96 0.05355 0.31472
202411_at IFI27 Interferon, alpha-inducible protein 27 32.67 15.61 2.09 0.05376 0.31472
208164_s_at IL9R Interleukin 9 receptor 4.71 5.64 0.84 0.05639 0.32338
208375_at IFNA1 Interferon, alpha 1 2.8 5.44 0.52 0.06403 0.34601
1555464_at IFIH1 Interferon induced with helicase C domain 1 70.3 50.39 1.4 0.06403 0.34601
1569861_at TRAF5 TNF receptor-associated factor 5 6.6 7.1 0.93 0.06403 0.34601
209687_at CXCL12 Chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1) 5.19 6.84 0.76 0.07578 0.40178
224283_x_at IL18BP Interleukin 18 binding protein 15.36 18.89 0.81 0.08023 0.41749
215561_s_at IL1R1 Interleukin 1 receptor, type I 5.66 9.41 0.6 0.08451 0.42486
202687_s_at TNFSF10 Tumor necrosis factor (ligand) superfamily, member 10, tumor necrosis factor (ligand) superfamily, member 10 556.18 440.74 1.26 0.08467 0.42486
234516_at IL1R1 Interleukin 1 receptor, type I 24.23 26.62 0.91 0.09437 0.43578
212196_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 131.01 127.64 1.03 0.0946 0.43578
206926_s_at IL11 Interleukin 11 11.27 10.34 1.09 0.09268 0.43578
221926_s_at IL17RC Interleukin 17 receptor C 4.33 4.36 0.99 0.09392 0.43578
205476_at CCL20 Chemokine (C-C motif) ligand 20 51.06 9.12 5.6 0.09404 0.43578
210548_at CCL23 Chemokine (C-C motif) ligand 23 3.53 4.61 0.77 0.09949 0.45091
216243_s_at IL1RN Interleukin 1 receptor antagonist 134.21 88.04 1.52 0.10519 0.46185
209827_s_at IL16 Interleukin 16 (lymphocyte chemoattractant factor) 198.96 253.61 0.78 0.1049 0.46185
211338_at IFNA2 Interferon, alpha 2 6.31 6.85 0.92 0.1101 0.47597
205099_s_at CCR1 Chemokine (C-C motif) receptor 1 381.92 370.82 1.03 0.11671 0.4969
205207_at IL6 Interleukin 6 (interferon, beta 2) 33.83 11.29 3 0.12912 0.49729
204773_at IL11RA Interleukin 11 receptor, alpha 35.77 37.85 0.94 0.12892 0.49729
222974_at IL22 Interleukin 22 6.78 5.04 1.35 0.12906 0.49729
220054_at IL23A Interleukin 23, alpha subunit p19 18.45 22.23 0.83 0.1225 0.49729
207113_s_at TNF Tumor necrosis factor 411.29 195.36 2.11 0.12276 0.49729
208075_s_at CCL7 Chemokine (C-C motif) ligand 7, chemokine (C-C motif) ligand 7 5.28 8.89 0.59 0.12892 0.49729
1569203_at CXCL2 Chemokine (C-X-C motif) ligand 2 36.79 18.62 1.98 0.12919 0.49729
207681_at CXCR3 Chemokine (C-X-C motif) receptor 3 34.98 46.84 0.75 0.13547 0.51442
39402_at IL1B Interleukin 1, beta 1285.79 443.95 2.9 0.14268 0.52501
207906_at IL3 Interleukin 3 (colony-stimulating factor, multiple) 2.26 2.21 1.02 0.14947 0.52501
208193_at IL9 Interleukin 9 3.69 3.14 1.17 0.14905 0.52501
206924_at IL11 Interleukin 11 2.88 3.68 0.78 0.14919 0.52501
235531_at IL17RB Interleukin 17 receptor B 20.83 20.61 1.01 0.14234 0.52501
214458_at TRAF3IP1 TNF receptor-associated factor 3 interacting protein 1 11.98 11.86 1.01 0.14878 0.52501
64440_at IL17RC Interleukin 17 receptor C 79.17 86.92 0.91 0.15723 0.52597
229450_at IFIT3 Interferon-induced protein with tetratricopeptide repeats 3 476.16 293.63 1.62 0.15723 0.52597
209774_x_at CXCL2 Chemokine (C-X-C motif) ligand 2 601.98 172.21 3.5 0.15723 0.52597
207850_at CXCL3 Chemokine (C-X-C motif) ligand 3 201.37 80.34 2.51 0.15723 0.52597
202948_at IL1R1 Interleukin 1 receptor, type I 31.23 37.41 0.83 0.16448 0.53815
212659_s_at IL1RN Interleukin 1 receptor antagonist 129.83 117.41 1.11 0.1647 0.53815
211372_s_at IL1R2 Interleukin 1 receptor, type II 15.5 19.1 0.81 0.17281 0.54583
1552915_at IL28A Interleukin 28A (interferon, lambda 2) 21.28 18.3 1.16 0.17288 0.54583
223710_at CCL26 Chemokine (C-C motif) ligand 26 19.21 17.31 1.11 0.17244 0.54583
205926_at IL27RA Interleukin 27 receptor, alpha 142.43 145.56 0.98 0.18105 0.55907
204932_at TNFRSF11B Tumor necrosis factor receptor superfamily, member 11b, osteoprotegerin (OGP) 10.14 12.21 0.83 0.18001 0.55907
220971_at IL17E Interleukin 17E 10.42 12.41 0.84 0.18921 0.56675
219255_x_at IL17RB Interleukin 17 receptor B 6.93 8.36 0.83 0.18853 0.56675
217199_s_at STAT2 Signal transducer and activator of transcription 2, 113 kDa 31.51 25.83 1.22 0.18959 0.56675
210118_s_at IL1A Interleukin 1, alpha 23.56 10.89 2.16 0.21594 0.57929
211516_at IL5RA Interleukin 5 receptor, alpha 5.92 8.51 0.69 0.21515 0.57929
202859_x_at IL8 Interleukin 8 1850.81 730.41 2.53 0.22677 0.57929
209828_s_at IL16 Interleukin 16 (lymphocyte chemoattractant factor) 23.08 34.55 0.67 0.2267 0.57929
208402_at IL17 Interleukin 17 (cytotoxic T-lymphocyte-associated serine esterase 8) 14.02 19.57 0.72 0.2059 0.57929
221165_s_at IL22 Interleukin 22 21.89 23.56 0.93 0.22486 0.57929
221111_at IL26 Interleukin 26 4.13 5.1 0.81 0.19841 0.57929
225669_at IFNAR1 Interferon (alpha, beta, and omega) receptor 1 37.99 40.96 0.93 0.22677 0.57929
1552611_a_at JAK1 Janus kinase 1 (a protein tyrosine kinase) 169.58 162.82 1.04 0.22677 0.57929
201422_at IFI30 Interferon, gamma-inducible protein 30 3459.22 3226.64 1.07 0.22646 0.57929
204352_at TRAF5 TNF receptor-associated factor 5 23.86 37.43 0.64 0.20762 0.57929
207900_at CCL17 Chemokine (C-C motif) ligand 17 20.27 20.66 0.98 0.22662 0.57929
207445_s_at CCR9 Chemokine (C-C motif) receptor 9 18.78 21.37 0.88 0.21657 0.57929
205242_at CXCL13 Chemokine (C-X-C motif) ligand 13 (B-cell chemoattractant) 2.43 3.62 0.67 0.1978 0.57929
211469_s_at CXCR6 Chemokine (C-X-C motif) receptor 6 4.67 6.83 0.68 0.21586 0.57929
203687_at CX3CL1 Chemokine (C-X3-C motif) ligand 1 4.28 5.34 0.8 0.20715 0.57929
218002_s_at CXCL14 Chemokine (C-X-C motif) ligand 14 2.03 2.11 0.96 0.23609 0.59767
205067_at IL1B Interleukin 1, beta 1436.05 513.56 2.8 0.25774 0.62978
210744_s_at IL5RA Interleukin 5 receptor, alpha 7.31 10.81 0.68 0.25733 0.62978
1552609_s_at IL28A /// IL28B Interleukin 28A (interferon, lambda 2), interleukin 28B (interferon, lambda 3) 10.3 10.99 0.94 0.25766 0.62978
242473_at TRAF4 TNF receptor-associated factor 4 8.1 10.37 0.78 0.25774 0.62978
243977_at IL6 Interleukin 6 (interferon, beta 2) 20.98 24.02 0.87 0.26814 0.64011
204103_at CCL4 Chemokine (C-C motif) ligand 4 828.94 274.36 3.02 0.2688 0.64011
32128_at CCL18 Chemokine (C-C motif) ligand 18 (pulmonary and activation-regulated) 13.14 15.52 0.85 0.26863 0.64011
207433_at IL10 Interleukin 10 6.19 7.02 0.88 0.29161 0.67187
212203_x_at IFITM3 Interferon induced transmembrane protein 3 (1-8U) 1196.83 954.47 1.25 0.2917 0.67187
211153_s_at TNFSF11 Tumor necrosis factor (ligand) superfamily, member 11, activator of NF-κB ligand (RANKL) 4.88 4.41 1.11 0.29137 0.67187
207794_at CCR2 Chemokine (C-C motif) receptor 2, chemokine (C-C motif) receptor 2 224.96 310.1 0.73 0.2917 0.67187
216244_at IL1RN Interleukin 1 receptor antagonist 4.14 3.79 1.09 0.31554 0.67755
220056_at IL22RA1 Interleukin 22 receptor, alpha 1 25.21 21.24 1.19 0.30247 0.67755
208173_at IFNB1 Interferon, beta 1, fibroblast 3.43 4.31 0.8 0.31521 0.67755
219209_at IFIH1 Interferon induced with helicase C domain 1 137.64 113.56 1.21 0.31571 0.67755
221571_at TRAF3 TNF receptor-associated factor 3 36.67 41.08 0.89 0.30354 0.67755
206983_at CCR6 Chemokine (C-C motif) receptor 6 4.79 7.61 0.63 0.31579 0.67755
208059_at CCR8 Chemokine (C-C motif) receptor 8 3.42 3.91 0.87 0.31554 0.67755
204470_at CXCL1 Chemokine (C-X-C motif) ligand 1 (melanoma growth stimulating activity, alpha) 64.18 28.14 2.28 0.31579 0.67755
206336_at CXCL6 Chemokine (C-X-C motif) ligand 6 (granulocyte chemotactic protein 2) 6.94 9.41 0.74 0.31587 0.67755
207072_at IL18RAP Interleukin 18 receptor accessory protein 32.1 70.39 0.46 0.32828 0.68858
216020_at IFIH1 Interferon induced with helicase C domain 1 10.33 7.56 1.36 0.32836 0.68858
207861_at CCL22 Chemokine (C-C motif) ligand 22 3.9 4.21 0.93 0.32728 0.68858
207037_at TNFRSF11A Tumor necrosis factor receptor superfamily, member 11a, activator of NF-κB, receptor activator of nuclear factor κB (RANK) 12.01 13.75 0.87 0.34092 0.69503
205114_s_at CCL3, CCL3L1 Chemokine (C-C motif) ligand 3, chemokine (C-C motif) ligand 3-like 1 1514.49 513.72 2.95 0.34133 0.69503
221463_at CCL24 Chemokine (C-C motif) ligand 24 4.12 7.67 0.54 0.341 0.69503
208304_at CCR3 Chemokine (C-C motif) receptor 3 55.88 68.99 0.81 0.34133 0.69503
228977_at IL17D Interleukin 17D 3.92 4.04 0.97 0.35405 0.69653
205707_at IL17R Interleukin 17 receptor 296.73 357.67 0.83 0.35446 0.69653
208261_x_at IFNA10 Interferon, alpha 10 12.66 14.89 0.85 0.35446 0.69653
208448_x_at IFNA16 Interferon, alpha 16 20 19.59 1.02 0.35413 0.69653
1562296_at CXCL14 Chemokine (C-X-C motif) ligand 14 10.64 7.69 1.38 0.35446 0.69653
211506_s_at IL8 Interleukin 8 1343.34 417.69 3.22 0.36807 0.69884
1552584_at IL12RB1 Interleukin 12 receptor, beta 1 81.71 88.5 0.92 0.36807 0.69884
208548_at IFNA6 Interferon, alpha 6 25.55 29.9 0.85 0.36741 0.69884
207354_at CCL16 Chemokine (C-C motif) ligand 16 7.33 8.09 0.91 0.36766 0.69884
204606_at CCL21 Chemokine (C-C motif) ligand 21 13.18 9.83 1.34 0.36774 0.69884
224079_at IL17C Interleukin 17C 35.95 36.44 0.99 0.39534 0.7044
219115_s_at IL20RA Interleukin 20 receptor, alpha 4.77 4.78 1 0.38117 0.7044
219971_at IL21R Interleukin 21 receptor 6.05 8.49 0.71 0.39582 0.7044
208344_x_at IFNA13 Interferon, alpha 13 24.68 14.86 1.66 0.38142 0.7044
203153_at IFIT1 Interferon-induced protein with tetratricopeptide repeats 1, interferon-induced protein with tetratricopeptide repeats 1 199.61 122.27 1.63 0.39607 0.7044
201601_x_at IFITM1 Interferon induced transmembrane protein 1 (9-27) 371.78 359.83 1.03 0.39607 0.7044
205558_at TRAF6 TNF receptor-associated factor 6 40.12 51.7 0.78 0.38101 0.7044
224027_at CCL28 Chemokine (C-C motif) ligand 28 12.05 12.17 0.99 0.3959 0.7044
203666_at CXCL12 Chemokine (C-X-C motif) ligand 12 (stromal cell-derived factor 1) 47.91 55.58 0.86 0.39558 0.7044
237038_at CXCL14 Chemokine (C-X-C motif) ligand 14 4.89 5.25 0.93 0.38044 0.7044
205291_at IL2RB Interleukin 2 receptor, beta, interleukin 2 receptor, beta 90.85 134.18 0.68 0.42532 0.7114
206148_at IL3RA Interleukin 3 receptor, alpha (low affinity) 33.42 29.59 1.13 0.42516 0.7114
211000_s_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 42.99 41.69 1.03 0.42524 0.7114
212195_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 333.64 330.73 1.01 0.42532 0.7114
207901_at IL12B Interleukin 12B (natural killer cell stimulatory factor 2, cytotoxic lymphocyte maturation factor 2, p40) 13.58 15.13 0.9 0.41006 0.7114
1552610_a_at JAK1 Janus kinase 1 (a protein tyrosine kinase) 195.54 234.77 0.83 0.42524 0.7114
238494_at TRAF3IP1 TNF receptor-associated factor 3 interacting protein 1 42.08 48.73 0.86 0.42436 0.7114
206988_at CCL25 Chemokine (C-C motif) ligand 25 9.38 9.41 1 0.42468 0.7114
224240_s_at CCL28 Chemokine (C-C motif) ligand 28 23.78 30.34 0.78 0.425 0.7114
1568934_at CX3CR1 Chemokine (C-X3-C motif) receptor 1 25.24 37.66 0.67 0.425 0.7114
201887_at IL13RA1 Interleukin 13 receptor, alpha 1 267.86 291.22 0.92 0.45571 0.72771
1561853_a_at IL23R Interleukin 23 receptor 4.61 4.55 1.01 0.45463 0.72771
242903_at IFNGR1 Interferon gamma receptor 1 265.56 251 1.06 0.45579 0.72771
214022_s_at IFITM1 Interferon induced transmembrane protein 1 (9-27) 593.06 624.52 0.95 0.45579 0.72771
208315_x_at TRAF3 TNF receptor-associated factor 3 66.38 70.17 0.95 0.4554 0.72771
206978_at CCR2 Chemokine (C-C motif) receptor 2, chemokine (C-C motif) receptor 2 556.27 705.5 0.79 0.45579 0.72771
207852_at CXCL5 Chemokine (C-X-C motif) ligand 5 12.5 16.09 0.78 0.45571 0.72771
206974_at CXCR6 Chemokine (C-X-C motif) receptor 6 10.88 15.49 0.7 0.4554 0.72771
217119_s_at CXCR3 Chemokine (C-X-C motif) receptor 3 10.84 21.84 0.5 0.4711 0.7479
211405_x_at IFNA17 Interferon, alpha 17 33.16 36.39 0.91 0.48701 0.76882
217489_s_at IL6R Interleukin 6 receptor 35.97 45.58 0.79 0.52027 0.7818
214950_at IL9R Interleukin 9 receptor 10.43 21.45 0.49 0.5197 0.7818
201888_s_at IL13RA1 Interleukin 13 receptor, alpha 1 107.98 114.14 0.95 0.5202 0.7818
219323_s_at IL18BP Interleukin 18 binding protein 11.17 18.06 0.62 0.52006 0.7818
1552995_at IL27 Interleukin 27 7.78 5.66 1.38 0.50336 0.7818
244261_at IL28RA Interleukin 28 receptor, alpha (interferon, lambda receptor) 11.39 17.45 0.65 0.52027 0.7818
210643_at TNFSF11 Tumor necrosis factor (ligand) superfamily, member 11, activator of NF-κB ligand (RANKL) 7.75 11.01 0.7 0.51998 0.7818
206991_s_at CCR5 Chemokine (C-C motif) receptor 5 53.27 98.45 0.54 0.5202 0.7818
205898_at CX3CR1 Chemokine (C-X3-C motif) receptor 1 1343.17 1679.71 0.8 0.52027 0.7818
220273_at IL17B Interleukin 17B 3.01 6.06 0.5 0.53668 0.79372
224071_at IL20 Interleukin 20 22.93 24.02 0.95 0.53605 0.79372
1555499_a_at IL28RA Interleukin 28 receptor, alpha (interferon, lambda receptor) 23.78 22.54 1.06 0.53668 0.79372
207538_at IL4 Interleukin 4 9.75 10.11 0.96 0.55412 0.80688
204912_at IL10RA Interleukin 10 receptor, alpha 681.13 656.72 1.04 0.55419 0.80688
223030_at TRAF7 TNF receptor-associated factor 7 13.44 18.42 0.73 0.55405 0.80688
205403_at IL1R2 Interleukin 1 receptor, type II 36.25 48.67 0.74 0.58915 0.81153
234967_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 3.65 3.37 1.08 0.58864 0.81153
1552646_at IL11RA Interleukin 11 receptor, alpha 46.73 58.54 0.8 0.56956 0.81153
222062_at IL27RA Interleukin 27 receptor, alpha 141.68 184.7 0.77 0.58915 0.81153
204191_at IFNAR1 Interferon (alpha, beta, and omega) receptor 1 28.97 25.98 1.12 0.58639 0.81153
206332_s_at IFI16 Interferon, gamma-inducible protein 16 742.15 756.26 0.98 0.58915 0.81153
211899_s_at TRAF4 TNF receptor-associated factor 4 8.43 9.49 0.89 0.57062 0.81153
223029_s_at TRAF7 TNF receptor-associated factor 7 39.65 31.97 1.24 0.57141 0.81153
210072_at CCL19 Chemokine (C-C motif) ligand 19 20.58 19.63 1.05 0.58896 0.81153
207955_at CCL27 Chemokine (C-C motif) ligand 27 29.49 33.85 0.87 0.5889 0.81153
211122_s_at CXCL11 Chemokine (C-X-C motif) ligand 11 17.69 8.56 2.07 0.57121 0.81153
205098_at CCR1 Chemokine (C-C motif) receptor 1 514.24 489.35 1.05 0.60695 0.83197
204116_at IL2RG Interleukin 2 receptor, gamma (severe combined immunodeficiency) 193.16 255.56 0.76 0.62505 0.83249
205945_at IL6R Interleukin 6 receptor, interleukin 6 receptor 258.64 261.18 0.99 0.62505 0.83249
205798_at IL7R Interleukin 7 receptor, interleukin 7 receptor 64.86 104.79 0.62 0.62511 0.83249
206295_at IL18 Interleukin 18 (interferon-γ-inducing factor) 67.16 76.06 0.88 0.62511 0.83249
208965_s_at IFI16 Interferon, gamma-inducible protein 16 347.81 327.78 1.06 0.62511 0.83249
1555759_a_at CCL5 Chemokine (C-C motif) ligand 5 972.23 900.04 1.08 0.62511 0.83249
204864_s_at IL6ST Interleukin 6 signal transducer (gp130, oncostatin M receptor) 29.53 30.2 0.98 0.66186 0.84938
221947_at IL17RC Interleukin 17 receptor C 47.88 44.71 1.07 0.66175 0.84938
217702_at IL27RA Interleukin 27 receptor, alpha 14.93 12.41 1.2 0.64337 0.84938
214569_at IFNA5 Interferon, alpha 5 6.93 6.7 1.03 0.66083 0.84938
1553574_at IFNE1 Interferon epsilon 1 15.13 14.11 1.07 0.66099 0.84938
201648_at JAK1 Janus kinase 1 (a protein tyrosine kinase) 543.47 603.1 0.9 0.66197 0.84938
204413_at TRAF2 TNF receptor-associated factor 2 3.8 4.76 0.8 0.6617 0.84938
214974_x_at CXCL5 Chemokine (C-X-C motif) ligand 5 529.1 524.14 1.01 0.66197 0.84938
207849_at IL2 Interleukin 2 6.56 6.19 1.06 0.68047 0.85388
208259_x_at IFNA7 Interferon, alpha 7 26.13 17.84 1.46 0.68057 0.85388
208182_x_at IFNA14 Interferon, alpha 14 27.87 34.38 0.81 0.67964 0.85388
202727_s_at IFNGR1 Interferon gamma receptor 1 1046.25 1094.15 0.96 0.68067 0.85388
210163_at CXCL11 Chemokine (C-X-C motif) ligand 11 17.34 8.8 1.97 0.68041 0.85388
226333_at IL6R Interleukin 6 receptor 370.68 448.76 0.83 0.69968 0.86232
1555016_at IL16 Interleukin 16 (lymphocyte chemoattractant factor) 37.26 36.32 1.03 0.69914 0.86232
204933_s_at TNFRSF11B Tumor necrosis factor receptor superfamily, member 11b, osteoprotegerin (OGP) 6.46 4.64 1.39 0.69968 0.86232
206337_at CCR7 Chemokine (C-C motif) receptor 7, chemokine (C-C motif) receptor 7 57.88 65.73 0.88 0.69968 0.86232
207008_at IL8RB Interleukin 8 receptor, beta 179.1 225.48 0.79 0.71877 0.87815
206890_at IL12RB1 Interleukin 12 receptor, beta 1 34.16 45.32 0.75 0.71877 0.87815
206999_at IL12RB2 Interleukin 12 receptor, beta 2 15.38 18.64 0.83 0.73792 0.88263
234408_at IL17F Interleukin 17F 2.32 2.44 0.95 0.73753 0.88263
201315_x_at IFITM2 Interferon induced transmembrane protein 2 (1-8D) 1306.87 1373.99 0.95 0.73814 0.88263
205392_s_at CCL14, / CCL15 Chemokine (C-C motif) ligand 14, chemokine (C-C motif) ligand 15 12.36 15.56 0.79 0.73722 0.88263
217028_at CXCR4 Chemokine (C-X-C motif) receptor 4 438.44 468.81 0.94 0.73814 0.88263
211269_s_at IL2RA Interleukin 2 receptor, alpha 24.39 26.68 0.91 0.75738 0.89052
221271_at IL21 Interleukin 21 6.93 7 0.99 0.75726 0.89052
209924_at CCL18 Chemokine (C-C motif) ligand 18 (pulmonary and activation-regulated) 18.18 16.69 1.09 0.75726 0.89052
203915_at CXCL9 Chemokine (C-X-C motif) ligand 9 42.84 36.42 1.18 0.75742 0.89052
216876_s_at IL17 Interleukin 17 (cytotoxic T-lymphocyte-associated serine esterase 8) 2.99 2.74 1.09 0.77715 0.90614
235116_at TRAF1 TNF receptor-associated factor 1 26.19 31.3 0.84 0.7767 0.90614
210133_at CCL11 Chemokine (C-C motif) ligand 11 13.59 17.24 0.79 0.79698 0.92161
208376_at CCR4 Chemokine (C-C motif) receptor 4 21.06 20.58 1.02 0.79671 0.92161
217212_s_at IL9R Interleukin 9 receptor 55.78 61.46 0.91 0.8169 0.92938
214059_at IFI44 Interferon-induced protein 44 67.79 53.63 1.26 0.81693 0.92938
230327_at CCL27 Chemokine (C-C motif) ligand 27 17.48 15.39 1.14 0.81681 0.92938
823_at CX3CL1 Chemokine (C-X3-C motif) ligand 1 21.62 19.67 1.1 0.81681 0.92938
207539_s_at IL4 Interleukin 4 19.68 18.36 1.07 0.85704 0.94123
203233_at IL4R Interleukin 4 receptor 120.73 114.06 1.06 0.85714 0.94123
209575_at IL10RB Interleukin 10 receptor, beta 279.27 295.77 0.94 0.89769 0.94123
211612_s_at IL13RA1 Interleukin 13 receptor, alpha 1, interleukin 13 receptor, alpha 1 150.14 153.82 0.98 0.89762 0.94123
227401_at IL17D Interleukin 17 receptor D 8.6 7.62 1.13 0.89758 0.94123
224156_x_at IL17RB Interleukin 17 receptor B 18.08 13.81 1.31 0.87718 0.94123
224361_s_at IL17RB Interleukin 17 receptor B 10.48 16.9 0.62 0.89753 0.94123
227997_at IL17RD Interleukin 17 receptor D 27.27 32.84 0.83 0.89762 0.94123
236186_x_at IL17RE Interleukin 17 receptor E 2.38 3.13 0.76 0.85702 0.94123
222868_s_at IL18BP Interleukin 18 binding protein 56.12 58.32 0.96 0.87729 0.94123
222829_s_at IL20RA Interleukin 20 receptor, alpha 4.78 3.86 1.24 0.87731 0.94123
1552917_at IL29 Interleukin 29 (interferon, lambda 1) 33.83 37.22 0.91 0.89769 0.94123
204786_s_at IFNAR2 Interferon (alpha, beta, and omega) receptor 2 124.38 130.38 0.95 0.89765 0.94123
211676_s_at IFNGR1 Interferon gamma receptor 1, interferon gamma receptor 1 479.53 517.04 0.93 0.85714 0.94123
205170_at STAT2 Signal transducer and activator of transcription 2, 113 kDa 47.35 46.01 1.03 0.83697 0.94123
208966_x_at IFI16 Interferon, gamma-inducible protein 16 591.69 599.19 0.99 0.85714 0.94123
238846_at TNFRSF11A Tumor necrosis factor receptor superfamily, member 11a, activator of NF-κB, receptor activator of nuclear factor κB (RANK) 18.53 19.76 0.94 0.85694 0.94123
207533_at CCL1 Chemokine (C-C motif) ligand 1 2.38 3.42 0.69 0.8976 0.94123
206407_s_at CCL13 Chemokine (C-C motif) ligand 13 3.59 6.21 0.58 0.83686 0.94123
215101_s_at CXCL5 Chemokine (C-X-C motif) ligand 5 95.13 96.57 0.99 0.89769 0.94123
211919_s_at CXCR4 Chemokine (C-X-C motif) receptor 4, chemokine (C-X-C motif) receptor 4 318.92 339.41 0.94 0.89767 0.94123
209201_x_at CXCR4 Chemokine (C-X-C motif) receptor 4 305.74 310.98 0.98 0.91805 0.959
210904_s_at IL13RA1 Interleukin 13 receptor, alpha 1 117.07 128.58 0.91 0.9385 0.97313
1405_i_at CCL5 Chemokine (C-C motif) ligand 5 1312.38 1268.12 1.03 0.9385 0.97313
202871_at TRAF4 TNF receptor-associated factor 4 18.68 17.18 1.09 0.95897 0.98707
223454_at CXCL16 Chemokine (C-X-C motif) ligand 16 108.07 104.49 1.03 0.95894 0.98707
207952_at IL5 Interleukin 5 (colony-stimulating factor, eosinophil) 10.71 13.63 0.79 0.97945 0.99721
207844_at IL13 Interleukin 13 18.97 32.38 0.59 0.97947 0.99721
224514_x_at IL17RC Interleukin 17 receptor C, interleukin 17 receptor C 29.28 36.3 0.81 0.97944 0.99721
206341_at IL2RA Interleukin 2 receptor, alpha 12.05 15.51 0.78 1 1
226218_at IL7R Interleukin 7 receptor 62.02 108.45 0.57 1 1
220745_at IL19 Interleukin 19 25.66 29.86 0.86 1 1
225661_at IFNAR1 Interferon (alpha, beta, and omega) receptor 1 76.46 82.39 0.93 1 1
204785_x_at IFNAR2 Interferon (alpha, beta, and omega) receptor 2 116.43 124.34 0.94 1 1

Note: The data were sorted by adjusted P value. Hybridized intensity and “present” status were given based on the MAS5 algorithm. L-BMD intensity means average hybridized intensity in the low BMD group; H-BMD intensity means average hybridized intensity in the high BMD group; Fold L/H means the ration of L-BMD intensity to H-BMD intensity. Raw P value represents P value before multiple testing correction. Adjusted P value represents P value adjusted with Benjamini/Hochberg method; asterisks indicate significant results after Benjamini-Hochberg correction considering 281 probes of selected genes.

Disclosures

The authors state that they have no conflicts of interest.

References

  • 1.Ralston SH. Genetic control of susceptibility to osteoporosis. J Clin Endocrinol Metab. 2002;87:2460–2466. doi: 10.1210/jcem.87.6.8621. [DOI] [PubMed] [Google Scholar]
  • 2.Liu YZ, Liu YJ, Recker RR, Deng HW. Molecular studies of identification of genes for osteoporosis: the 2002 update. J Endocrinol. 2003;177:147–196. doi: 10.1677/joe.0.1770147. [DOI] [PubMed] [Google Scholar]
  • 3.Liu YJ, Shen H, Xiao P, et al. Molecular genetic studies of gene identification for osteoporosis: a 2004 update. J Bone Miner Res. 2006;21:1511–1535. doi: 10.1359/JBMR.051002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Arron JR, Choi Y. Bone versus immune system. Nature. 2000;408:535–536. doi: 10.1038/35046196. [DOI] [PubMed] [Google Scholar]
  • 5.Baron R. Arming the osteoclast. Nat Med. 2004;10:458–460. doi: 10.1038/nm0504-458. [DOI] [PubMed] [Google Scholar]
  • 6.Rho J, Takami M, Choi Y. Osteoimmunology: interactions of the immune and skeletal systems. Mol Cells. 2004;17:1–9. [PubMed] [Google Scholar]
  • 7.Walsh MC, Kim N, Kadono Y, et al. Osteoimmunology: interplay between the immune system and bone metabolism. Annu Rev Immunol. 2006;24:33–63. doi: 10.1146/annurev.immunol.24.021605.090646. [DOI] [PubMed] [Google Scholar]
  • 8.Takayanagi H. Osteoimmunology: shared mechanisms and crosstalk between the immune and bone systems. Nat Rev Immunol. 2007;7:292–304. doi: 10.1038/nri2062. [DOI] [PubMed] [Google Scholar]
  • 9.Takayanagi H, Kim S, Koga T, Taniguchi T. Stat1-mediated cytoplasmic attenuation in osteoimmunology. J Cell Biochem. 2005;94:232–240. doi: 10.1002/jcb.20316. [DOI] [PubMed] [Google Scholar]
  • 10.Nathan CF. Secretory products of macrophages. J Clin Invest. 1987;79:319–326. doi: 10.1172/JCI112815. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Suda T, Takahashi N, Martin TJ. Modulation of osteoclast differentiation. Endocr Rev. 1992;13:66–80. doi: 10.1210/edrv-13-1-66. [DOI] [PubMed] [Google Scholar]
  • 12.Blair HC, Athanasou NA. Recent advances in osteoclast biology and pathological bone resorption. Histol Histopathol. 2004;19:189–199. doi: 10.14670/HH-19.189. [DOI] [PubMed] [Google Scholar]
  • 13.Quinn JM, Neale S, Fujikawa Y, McGee JO, Athanasou NA. Human osteoclast formation from blood monocytes, peritoneal macrophages, and bone marrow cells. Calcif Tissue Int. 1998;62:527–531. doi: 10.1007/s002239900473. [DOI] [PubMed] [Google Scholar]
  • 14.Matsuzaki K, Udagawa N, Takahashi N, et al. Osteoclast differentiation factor (ODF) induces osteoclast-like cell formation in human peripheral blood mononuclear cell cultures. Biochem Biophys Res Commun. 1998;246:199–204. doi: 10.1006/bbrc.1998.8586. [DOI] [PubMed] [Google Scholar]
  • 15.Rho J, Altmann CR, Socci ND, et al. Gene expression profiling of osteoclast differentiation by combined suppression subtractive hybridization (SSH) and cDNA microarray analysis. DNA Cell Biol. 2002;21:541–549. doi: 10.1089/104454902320308915. [DOI] [PubMed] [Google Scholar]
  • 16.Liu YZ, Dvornyk V, Lu Y, et al. A novel pathophysiological mechanism for osteoporosis suggested by an in vivo gene expression study of circulating monocytes. J Biol Chem. 2005;280:29011–29016. doi: 10.1074/jbc.M501164200. [DOI] [PubMed] [Google Scholar]
  • 17.Van Laere SJ, Van dA I, Van den Eynden GG, et al. Nuclear factor-κB signature of inflammatory breast cancer by cDNA microarray validated by quantitative real-time reverse transcription-PCR, immunohistochemistry, and nuclear factor-κB DNA-binding. Clin Cancer Res. 2006;12:3249–3256. doi: 10.1158/1078-0432.CCR-05-2800. [DOI] [PubMed] [Google Scholar]
  • 18.Osman I, Bajorin DF, Sun TT, et al. Novel blood biomarkers of human urinary bladder cancer. Clin Cancer Res. 2006;12:3374–3380. doi: 10.1158/1078-0432.CCR-05-2081. [DOI] [PubMed] [Google Scholar]
  • 19.Wang Z, Lewis MG, Nau ME, Arnold A, Vahey MT. Identification and utilization of inter-species conserved (ISC) probesets on Affymetrix human GeneChip platforms for the optimization of the assessment of expression patterns in non human primate (NHP) samples. BMC Bioinformatics. 2004;5:165. doi: 10.1186/1471-2105-5-165. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Canales RD, Luo Y, Willey JC, et al. Evaluation of DNA microarray results with quantitative gene expression platforms. Nat Biotechnol. 2006;24:1115–1122. doi: 10.1038/nbt1236. [DOI] [PubMed] [Google Scholar]
  • 21.Irizarry RA, Hobbs B, Collin F, et al. Exploration, normalization, and summaries of high density oligonucleotide array probe level data. Biostatistics. 2003;4:249–264. doi: 10.1093/biostatistics/4.2.249. [DOI] [PubMed] [Google Scholar]
  • 22.Benjamini Y, Hochberg Y. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J R Statist Soc B. 1995;57:289–300. [Google Scholar]
  • 23.Getz G, Levine E, Domany E. Coupled two-way clustering analysis of gene microarray data. Proc Natl Acad Sci USA. 2000;97:12079–12084. doi: 10.1073/pnas.210134797. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Purcell S, Neale B, Todd-Brown K, et al. PLINK: a tool set for whole-genome association and population-based linkage analyses. Am J Hum Genet. 2007;81:559–575. doi: 10.1086/519795. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Barrett JC, Fry B, Maller J, Daly MJ. Haploview: analysis and visualization of LD and haplotype maps. Bioinformatics. 2005;21:263–265. doi: 10.1093/bioinformatics/bth457. [DOI] [PubMed] [Google Scholar]
  • 26.Marinescu VD, Kohane IS, Riva A. MAPPER: a search engine for the computational identification of putative transcription factor binding sites in multiple genomes. BMC Bioinformatics. 2005;6:79. doi: 10.1186/1471-2105-6-79. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Lu T, Pan Y, Kao SY, et al. Gene regulation and DNA damage in the ageing human brain. Nature. 2004;429:883–891. doi: 10.1038/nature02661. [DOI] [PubMed] [Google Scholar]
  • 28.Buttner P, Mosig S, Funke H. Gene expression profiles of T lymphocytes are sensitive to the influence of heavy smoking: a pilot study. Immunogenetics. 2007;59:37–43. doi: 10.1007/s00251-006-0177-3. [DOI] [PubMed] [Google Scholar]
  • 29.Peretz A, Peck EC, Bammler TK, et al. Diesel exhaust inhalation and assessment of peripheral blood mononuclear cell gene transcription effects: an exploratory study of healthy human volunteers. Inhal Toxicol. 2007;19:1107–1119. doi: 10.1080/08958370701665384. [DOI] [PubMed] [Google Scholar]
  • 30.Buttner P, Mosig S, Lechtermann A, Funke H, Mooren FC. Exercise affects the gene expression profiles of human white blood cells. J Appl Physiol. 2007;102:26–36. doi: 10.1152/japplphysiol.00066.2006. [DOI] [PubMed] [Google Scholar]
  • 31.Stroncek DF, Basil C, Nagorsen D, et al. Delayed polarization of mononuclear phagocyte transcriptional program by type I interferon isoforms. J Transl Med. 2005;3:24. doi: 10.1186/1479-5876-3-24. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Bridge AJ, Pebernard S, Ducraux A, Nicoulaz AL, Iggo R. Induction of an interferon response by RNAi vectors in mammalian cells. Nat Genet. 2003;34:263–264. doi: 10.1038/ng1173. [DOI] [PubMed] [Google Scholar]
  • 33.Crow MK, Wohlgemuth J. Microarray analysis of gene expression in lupus. Arthritis Res Ther. 2003;5:279–287. doi: 10.1186/ar1015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Der SD, Zhou A, Williams BR, Silverman RH. Identification of genes differentially regulated by interferon alpha, beta, or gamma using oligonucleotide arrays. Proc Natl Acad Sci USA. 1998;95:15623–15628. doi: 10.1073/pnas.95.26.15623. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Takayanagi H, Sato K, Takaoka A, Taniguchi T. Interplay between interferon and other cytokine systems in bone metabolism. Immunol Rev. 2005;208:181–193. doi: 10.1111/j.0105-2896.2005.00337.x. [DOI] [PubMed] [Google Scholar]
  • 36.Lee C, Lim HK, Sakong J, Lee YS, Kim JR, Baek SH. Janus kinase-signal transducer and activator of transcription mediates phosphatidic acid-induced interleukin (IL)-1β and IL-6 production. Mol Pharmacol. 2006;69:1041–1047. doi: 10.1124/mol.105.018481. [DOI] [PubMed] [Google Scholar]
  • 37.Herrmann F, Gebauer G, Lindemann A, Brach M, Mertelsmann R. Interleukin-2 and interferon-γ recruit different subsets of human peripheral blood monocytes to secrete interleukin-1β and tumour necrosis factor-α. Clin Exp Immunol. 1989;77:97–100. [PMC free article] [PubMed] [Google Scholar]
  • 38.Rendon-Mitchell B, Ochani M, Li J, et al. IFN-γ induces high mobility group box 1 protein release partly through a TNF-dependent mechanism. J Immunol. 2003;170:3890–3897. doi: 10.4049/jimmunol.170.7.3890. [DOI] [PubMed] [Google Scholar]
  • 39.Lei SF, Wu S, Li LM, et al. An in vivo genome wide gene expression study of circulating monocytes suggested GBP1, STAT1, and CXCL10 as novel risk genes for the differentiation of peak bone mass. Bone. 2009;44:1010–1014. doi: 10.1016/j.bone.2008.05.016. [DOI] [PubMed] [Google Scholar]
  • 40.Ungureanu D, Vanhatupa S, Gronholm J, Palvimo JJ, Silvennoinen O. SUMO-1 conjugation selectively modulates STAT1-mediated gene responses. Blood. 2005;106:224–226. doi: 10.1182/blood-2004-11-4514. [DOI] [PubMed] [Google Scholar]
  • 41.Wu H, Arron JR. TRAF6, a molecular bridge spanning adaptive immunity, innate immunity and osteoimmunology. Bioessays. 2003;25:1096–1105. doi: 10.1002/bies.10352. [DOI] [PubMed] [Google Scholar]
  • 42.Hu X, Li WP, Meng C, Ivashkiv LB. Inhibition of IFN-γ signaling by glucocorticoids. J Immunol. 2003;170:4833–4839. doi: 10.4049/jimmunol.170.9.4833. [DOI] [PubMed] [Google Scholar]
  • 43.Kuroiwa T, Schlimgen R, Illei GG, Boumpas DT. Monocyte response to Th1 stimulation and effector function toward human mesangial cells are not impaired in patients with lupus nephritis. Clin Immunol. 2003;106:65–72. doi: 10.1016/s1521-6616(02)00022-0. [DOI] [PubMed] [Google Scholar]
  • 44.Xiao L, Naganawa T, Obugunde E, et al. Stat1 controls postnatal bone formation by regulating fibroblast growth factor signaling in osteoblasts. J Biol Chem. 2004;279:27743–27752. doi: 10.1074/jbc.M314323200. [DOI] [PubMed] [Google Scholar]
  • 45.Orlic I, Borovecki F, Simic P, Vukicevic S. Gene expression profiling in bone tissue of osteoporotic mice. Arh Hig Rada Toksikol. 2007;58:3–11. doi: 10.2478/v10004-007-0001-y. [DOI] [PubMed] [Google Scholar]
  • 46.Xiao P, Shen H, Guo YF, et al. Genomic regions identified for BMD in a large sample including epistatic interactions and gender-specific effects. J Bone Miner Res. 2006;21:1536–1544. doi: 10.1359/jbmr.060717. [DOI] [PubMed] [Google Scholar]
  • 47.Wang L, Liu YJ, Xiao P, et al. Chromosome 2q32 may harbor a QTL affecting BMD variation at different skeletal sites. J Bone Miner Res. 2007;22:1672–1678. doi: 10.1359/jbmr.070722. [DOI] [PubMed] [Google Scholar]
  • 48.Hsu YH, Xu X, Terwedow HA, et al. Large-scale genome-wide linkage analysis for loci linked to BMD at different skeletal sites in extreme selected sibships. J Bone Miner Res. 2007;22:184–194. doi: 10.1359/jbmr.061015. [DOI] [PubMed] [Google Scholar]
  • 49.Ozkurt IC, Tetradis S. Parathyroid hormone-induced E4BP4/NFIL3 downregulates transcription in osteoblasts. J Biol Chem. 2003;278:26803–26809. doi: 10.1074/jbc.M212652200. [DOI] [PubMed] [Google Scholar]
  • 50.Ozkurt IC, Pirih FQ, Tetradis S. Parathyroid hormone induces E4bp4 messenger ribonucleic acid expression primarily through cyclic adenosine 3',5'-monophosphate signaling in osteoblasts. Endocrinology. 2004;145:3696–3703. doi: 10.1210/en.2003-1436. [DOI] [PubMed] [Google Scholar]
  • 51.Wallace AD, Wheeler TT, Young DA. Inducibility of E4BP4 suggests a novel mechanism of negative gene regulation by glucocorticoids. Biochem Biophys Res Commun. 1997;232:403–406. doi: 10.1006/bbrc.1997.6206. [DOI] [PubMed] [Google Scholar]
  • 52.Roodman GD. Cell biology of the osteoclast. Exp Hematol. 1999;27:1229–1241. doi: 10.1016/s0301-472x(99)00061-2. [DOI] [PubMed] [Google Scholar]

Articles from Journal of Bone and Mineral Research are provided here courtesy of Oxford University Press

RESOURCES