Abstract
Background
Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis in the world. Reliable biomarkers are required for the non‐invasive diagnosis and monitoring of IgAN. This study aims to investigate the difference in urinary exosomal microRNA (miRNA) expression profiles between patients with IgA nephropathy (IgAN) and healthy controls, which may provide clues to identify novel potential non‐invasive miRNA biomarkers for renal diseases.
Methods
Urine samples were collected from eighteen healthy controls and eighteen patients with IgAN. Differential centrifugation was performed to isolate exosomes from urine samples. High‐throughput sequencing and real‐time quantitative polymerase chain reaction (RT‐qPCR) were sequentially used to screen and further validate miRNA expression profiles in urinary exosomes of patients with IgAN in two independent cohorts.
Results
Urinary exosomes were successfully isolated to obtain exosomal miRNAs. MiR‐215‐5p and miR‐378i were significantly upregulated in urinary exosomes of patients with IgAN compared with healthy controls (P<.01), while miR‐29c and miR‐205‐5p were significantly downregulated (P<.05). MiR‐215‐5p, miR‐378i, miR‐365b‐3p and miR‐135b‐5p were found to have altered expression in patients with IgAN from validation cohorts, which was consistent with the high‐throughput sequencing analysis.
Conclusion
This study suggests that there is a significant difference in urinary exosomal miRNA profiles between patients with IgAN and healthy controls. These exosomal miRNAs, such as miR‐29c, miR‐146a and miR‐205 may potentially serve as novel non‐invasive biomarkers for IgAN.
Keywords: biomarker, IgA nephropathy, microRNA, urinary exosomes
1. Introduction
Immunoglobulin A nephropathy (IgAN) is the most common type of primary glomerulonephritis in the world, and is characterized by the presence of predominant IgA1 deposits in the glomerular mesangium.1, 2 Approximately 15%‐40% of patients with IgAN develop end‐stage renal disease (ESRD) in 10‐20 years.3, 4 It is believed that early diagnosis is critically important to prevent IgAN progression to ESRD.5 At present, renal biopsy is the gold standard for the diagnosis of IgAN.6, 7 However, it is not frequently performed for patients, because the majority of them are asymptomatic. In addition, there are limitations in estimating disease activity; which are due to inconclusive findings and reports of severe complications.6, 7 Therefore, reliable biomarkers are required for the non‐invasive diagnosis and monitoring of IgAN.
Exosomes are small membrane vesicles with a diameter of 30‐120 nm, and are present in nearly all biological fluids including urine.8, 9, 10, 11, 12 Urinary exosomes contain proteins, mRNAs and miRNAs, which are secreted by cells from all nephron segments; providing an accurate representation of renal dysfunction and structural injury. Thus, urinary exosomes may be suitable for the identification of biomarkers for chronic kidney disease.13, 14 Barutta et al.15 have established distinct urinary exosomal miRNA profiles between type 1 diabetes patients with and without incipient diabetic nephropathy, suggesting that miR‐145 may represent a novel candidate biomarker/player for type 1 diabetes with incipient diabetic nephropathy. A recent study conducted by Ramezani et al.16 has also demonstrated significant differences in plasma and urinary exosomal miRNA profiles between patients with MCD and FSGS, suggesting that certain miRNAs potentially serve as novel biological markers for distinguishing FSGS from MCD. Furthermore, accumulating evidence has indicated that the dysregulation of miRNAs such as miR‐146a, miR‐155,17 miR‐148b,18 miR‐29c19 and let‐7b20 is involved in the pathogenesis and progression of IgAN. Taken together, these findings give rise to the hypothesis that urinary exosomal miRNAs in IgAN patients may serve as novel non‐invasive biomarkers.
Therefore, in the present study, we investigated the difference in urinary exosomal miRNA profiles between IgAN patients and healthy controls, and identified some differentially expressed miRNAs, which could potentially serve as non‐invasive biomarkers for this disease.
2. Materials and Methods
2.1. Study design
In this study, screening and validation phases were designed. In the screening phase, urine samples from 12 patients with IgAN and 12 healthy controls were subjected to high‐throughput sequencing, in order to identify significantly and differentially expressed miRNAs. Then, the candidate miRNAs were validated by RT‐qPCR in urine samples from six patients with IgAN and six healthy controls.
2.2. Subjects
Eighteen patients with incipient IgAN, who were confirmed by renal biopsy from October 2012 to October 2013 at the Nephrology Department of the Second Affiliated Hospital of Nanchang University, were consecutively recruited for this study. Patients with chronic renal fibrosis and other concomitant renal diseases were excluded. Eighteen healthy volunteers from the Physical Examination Center of the same hospital were recruited into the study as controls. Demographic and baseline clinical data such as age, gender, 24‐hour urinary protein excretion (UPE) and serum creatinine (SCr) were recorded at the time of kidney biopsy. All procedures performed in studies involving human participants were in accordance with the ethical standards of the Ethical Committee of the Second Affiliated Hospital of Nanchang University and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study.
2.3. Sample collection and exosomes purification
A whole‐stream morning urine specimen was collected from each patient and healthy control. Exosomes were isolated from the urine specimen using differential centrifugation. Briefly, the urine sample was centrifuged at 2000 g for 20 minutes to remove the cells and debris. The cell‐free supernatant was centrifuged at 17 000 g for 15 minutes at 4°C to remove the large membrane vesicles. Then, the supernatant was filtered through a 0.22‐μm bacterial filter to remove particles larger than 200 nm. Subsequently, the resulting supernatant was centrifuged using an Optima L‐80XP Ultracentrifuge (SW41 rotor; Beckman Coulter, Fullerton, CA, USA) at 200 000 g for 60 minutes at 4°C to pellet the exosomes. The resulting pellets were resuspended in phosphate‐buffered saline (PBS), followed by repeat centrifugation at 200 000 g for 60 minutes at 4°C. Finally, the putative exosome pellets were resuspended in PBS and stored at −80°C for later use.
2.4. Scanning Electron Microscopy (SEM)
The pelleted putative exosomes were fixed with 2.5% glutaraldehyde (Sigma‐Aldrich GmbH, Taufkirchen, Germany) overnight, and subsequently centrifuged at 200 000 g for 60 minutes at 4°C to pellet the fixed exosomes that were washed twice with PBS. The resulting pellets were gently washed stepwise with 15%, 30%, 60% and 80% ethanol for dehydration, and resuspended in 0.5 mL of 10% ethanol. The resulting sample was loaded onto an 8×8 mm aluminum substrate, and was air dried. The aluminum substrate was coated with gold‐palladium by sputtering for observation under SEM (Quanta 400 instrument; FEI, Eindhoven, Netherlands).
2.5. Size distribution analysis
Urinary exosomes were isolated as described above, and resuspended in 1.0 mL of PBS. Samples were examined using a Nano Particle Size Analyzer (PSA NANO2590; Malvern Instruments Ltd., Malvern, UK), according to manufacturer's instructions.
2.6. Western blot
Total proteins of the isolated exosomes were extracted using a protein extraction kit (Applygen Technologies Inc., Beijing, China), according to manufacturer's protocols. Concentrations were determined using a BCA protein assay kit. Then, the proteins were separated by 8%‐10% sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE), and transferred onto polyvinylidene difluoride (PVDF) membranes. The membranes were blocked with 5% skim milk, followed by incubation with primary antibodies against EV marker Alix (Anti‐PDC6I antibody, 1:500 dilution; Abcam, Cambridge, UK) and appropriate horseradish peroxidase‐conjugated secondary antibodies. Blots were visualized with chemiluminescence reagents (Beyotime, Shanghai, China).
2.7. RNA extractions
In order to obtain enough RNA to successfully construct cDNA libraries for high‐throughput sequencing, urinary exosomes of twelve patients with IgAN were pooled in screen cohorts; and the same was carried out on the 12 healthy controls. Total RNA was extracted from the exosomes using TRIzol reagent (Invitrogen, Carlsbad, CA, USA) and a miRNeasy mini kit (Qiagen, Hildesheim, Germany), according to manufacturer's protocols. RNA samples were stored at −80°C for later use. The quantity and purity of the RNA samples were evaluated using the ND‐1000 Nanodrop instrument (Thermo Fisher Scientific, Waltham, MA, USA). RNA integrity was evaluated using the Agilent 2200 TapeStation (Agilent Technologies, Santa Clara, CA, USA).
2.8. cDNA library construction and high‐throughput sequencing
In the present study, high‐throughput sequencing was performed on one pooled urinary exosome sample from the twelve patients with IgAN; and the same was performed on one pooled urinary exosome sample from the twelve healthy controls. Briefly, RNAs were ligated with the 3′‐ and 5′‐ adapters, followed by reverse transcription using adaptor‐specific primers. Resulting PCR products, cDNA, were size‐selected with PAGE gel, according to the protocol of the TruSeq® Small RNA Sample Prep Kit (Illumina, San Diego, TX, USA). The purified cDNA library was evaluated using the Agilent 2200 TapeStation, and diluted to 10 pmol/L for cluster generation in situ on the HiSeq2500 (Illumina, USA) single‐end flow cell, followed by sequencing (1×50 bp).
2.9. Sequencing data analysis
In order to obtain high‐quality clean sequencing data, the preprocessing of reads and removal of adaptors were performed, together with the evaluation of Q20, Q30 and GC content levels of the clean data. Then, the clean reads were aligned to a reference genome that was downloaded from the National Center for Biotechnology Institute (NCBI) using TopHat (Broad Institute, Cambridge, MA, USA). ANNOVAR was used to generate functional annotations of genetic variants.21 The differential expression of genes and transcripts aligned by TopHat from clean reads between these two groups were examined using the Cuffilinks software package.22 Based on the total number of reads, the transcripts were also quantified using the cuffdiff program. Corrected P‐value ≤.05 and∣log2 (fold‐change)∣value ≥1 were set as thresholds for judging the significant difference in gene expression between different groups.
2.10. RT‐qPCR analysis
In order to validate the results from high‐throughput sequencing, miR‐215‐5p, miR‐378i, miR‐365b‐3p and miR‐135b‐5p were used for RT‐qPCR analysis based on expression level, as well as biological significance. Primers for candidate miRNAs were designed and synthesized by RiboBio Co., Ltd. (Guangzhou, China). Two‐hundred ng of total RNA was used for each 20 μL of reaction system. Reverse transcription was conducted using a PrimeScript RT reagent kit (Takara, Dalian, China), according to manufacturer's instructions. RT‐qPCR was performed on an Applied Biosystems 7500 Fast Dx Real‐Time PCR Instrument (Applied Biosystems, Carlsbad, CA, USA) using a SYBR Green PCR Kit (Takara) with the following conditions: 95°C for 20 seconds, followed by 40 cycles of 95°C for 10 seconds and 60°C for 20 seconds, and 70°C for 30 seconds. All PCR reactions were carried out in triplicate. A melt curve was generated and used to validate the specificity and identity of the PCR reactions. RNU6 served as the endogenous reference control. A relative expression software tool, REST 2009, was used to analyze the relative expression of miRNAs and as previously described.23
2.11. Statistical analysis
SPSS version 17.0 (SPSS Inc., Chicago, IL, USA) and REST 2009 software (Qiagen) for Windows were used for statistical analysis and graphing. Data were compared using the Mann‐Whitney U test, randomization test and Kruskal‐Wallis test, wherever appropriate. A P‐value <.05 was considered statistically significant.
3. Results
3.1. Subjects characteristics
The demographic and baseline clinical data of subjects in the screening and validation cohorts were recorded at the time of renal biopsy, and are summarized in Table 1. Patients with IgAN had significantly higher levels of 24‐hour UPE and SCr than healthy controls.
Table 1.
Baseline demographic and clinical data of subjects in the screening and validation cohorts
| Screening cohorts | Validation cohorts | |||
|---|---|---|---|---|
| IgAN | HC | IgAN | HC | |
| Case | 12 | 12 | 6 | 6 |
| Age (y) | 38.00±8.18 | 32.33±7.51 | 29.33±8.52 | 29.50±6.53 |
| Gender (M:F) | 8:4 | 8:4 | 4:2 | 3:3 |
| UPE (g/24 h) | 2.59±1.01 | 0.00 | 3.34±1.94 | 0.00 |
| SCr (μmol/L) | 179.00±21.52 | 77.20±13.05 | 163.25±21.91 | 68.87±10.46 |
IgAN, IgA nephropathy; HC, Healthy control; UPE, urinary protein excretion; SCr, serum creatinine.
3.2. Identification and characterization of urinary exosomes
Exosomes from each urine sample were isolated using differential centrifugation, as previously described. Scanning electron microscopy was used to directly visualize the harvested exosomes. As shown in Figure 1A and B, exosomes with a diameter of 30‐40 nm were indeed abundant in the pellets. The size distribution of exosomes was measured using a qNano instrument. As shown in Figure 2A and B, the major size of urinary exosomes was 30‐50 nm in diameter in healthy controls and 20‐50 nm in patients with IgAN; which were consistent with the true size of exosomes. Western blot confirmed that the exosomal markers CD63, Alix were present (Figure 3).
Figure 1.
Scanning electron microscope images of isolated exosomes. Exosomes aggregation with coexisting protein derived from urine, such as Tamm‐Horsfall protein (THP), was observed. Bars=500 nm, as indicated in the images. (A) Exosomes isolated from a urine sample obtained from healthy controls is shown. (B) Exosomes isolated from a urine sample obtained from a patient with immunoglobulin A nephropathy is shown
Figure 2.
Size distribution of exosomes by a Nano Particle Size Analyzer. (A) The size of exosomes isolated from the urine sample obtained from healthy controls is shown. Size distribution was approximately 30‐50 nm. (B) The size of exosomes isolated from the urine sample of a patient with immunoglobulin A nephropathy is shown. Size distribution was approximately 20‐50 nm
Figure 3.
Western blot for exosomes markers. The western blot analysis identified the presence of CD63, Alix on exosomes. HC, Healthy Controls; exo, exosomes
3.3. Differentially expressed miRNA profiles in the screening phase
Total RNA in exosomes were extracted and analyzed. The concentration of pre‐sequence total RNA are 4.40 ng/μL in exosomes samples derive from healthy controls and 7.40 ng/μL in exosomes samples derive from patients with IgAN. The peak image of RNA by Agilent 2200 TapeStation showed that small RNA including miRNA with a good integrity were contained in exosomes (Figure 4).
Figure 4.
Peak image of RNA contained in exosomes. The peak image by bioanalyzer show that the main RNA enriched in exosomes was <200nt, which was consistent with previous reports
High‐throughput sequencing was performed in the screening phase to characterize the miRNA expression profiles of exosomes in urine samples of patients with IgAN and healthy controls. As shown in Figure 5 and Table 2, 158 differentially expressed exosomal miRNAs were identified. Among these miRNAs, 21 miRNAs were differentially expressed with statistical significance at |log2fold‐change| >1 and P<.01, and another 20 miRNAs were differentially expressed with significance at |log2fold‐change| >1 and P<.05. Furthermore, among the 21 miRNAs with P<.01, 12 miRNAs were upregulated and nine miRNAs were downregulated in the patient group, compared with the control group.
Figure 5.
Unsupervised hierarchical clustering and heat maps of miRNA expression profile. miRNA expression pattern of urinary exosomes of patients with immunoglobulin A nephropathy and healthy controls were examined using high‐throughput sequencing. Heat map colours represent relative miRNA expression as indicated in the colour scale: red represents high expression; green represents low expression
Table 2.
Differential expression profiles of miRNAs with statistical significance in patients in the IgAN group vs healthy controls group
| miRNA_ID | |log2(fold‐change)| | P‐value |
|---|---|---|
| hsa‐miR‐378i | 26.1270 | <.01 |
| hsa‐miR‐215‐5p | 26.0175 | <.01 |
| hsa‐miR‐135b‐5p | 20.7210 | <.01 |
| hsa‐miR‐486‐5p | 20.0716 | <.01 |
| hsa‐miR‐708‐3p | 19.8516 | <.01 |
| hsa‐miR‐451a | 18.2123 | <.01 |
| hsa‐miR‐146b‐3p | 18.0069 | <.01 |
| hsa‐miR‐365b‐3p | 17.7404 | <.01 |
| hsa‐miR‐211‐5p | 17.5317 | <.01 |
| hsa‐miR‐509‐3p | 17.3694 | <.01 |
| hsa‐miR‐514a‐3p | 17.1735 | <.01 |
| hsa‐miR‐320c | 17.0360 | <.05 |
| hsa‐miR‐181c‐5p | 16.9358 | <.01 |
| hsa‐miR‐548o‐3p | 16.7845 | <.05 |
| hsa‐miR‐508‐3p | 16.5621 | <.05 |
| hsa‐miR‐378d | 16.5214 | <.05 |
| hsa‐miR‐365a‐3p | 16.0289 | <.05 |
| hsa‐miR‐326 | 16.0289 | <.05 |
| hsa‐miR‐27a‐3p | 8.8987 | <.01 |
| hsa‐miR‐30e‐3p | 8.8425 | <.01 |
| hsa‐miR‐126‐3p | 6.1091 | <.01 |
| hsa‐miR‐10b‐3p | 4.7267 | <.01 |
| hsa‐miR‐34a‐5p | 3.5878 | <.01 |
| hsa‐miR‐378a‐3p | 2.8378 | <.05 |
| hsa‐miR‐361‐3p | 2.8269 | <.05 |
| hsa‐miR‐146a‐5p | 2.7910 | <.05 |
| hsa‐miR‐29c‐5p | 2.3692 | <.05 |
| hsa‐miR‐30b‐5p | 2.0204 | <.01 |
| hsa‐miR‐31‐5p | 2.0104 | <.01 |
| hsa‐miR‐500b‐5p | 1.7610 | <.05 |
| hsa‐let‐7 g‐5p | 1.7095 | <.01 |
| hsa‐miR‐374b‐5p | 1.6312 | <.01 |
| hsa‐miR‐10a‐3p | 1.6030 | <.05 |
| hsa‐miR‐205‐5p | 1.2863 | <.05 |
| hsa‐miR‐151b | 1.2089 | <.05 |
| hsa‐miR‐374a‐5p | 1.2055 | <.05 |
| hsa‐miR‐186‐5p | 1.1927 | <.05 |
| hsa‐miR‐29a‐3p | 1.1693 | <.05 |
| hsa‐miR‐125a‐5p | 1.1573 | <.05 |
| hsa‐miR‐16‐5p | 1.1067 | <.05 |
| hsa‐miR‐29c‐3p | 1.0377 | <.05 |
3.4. Validation of candidate miRNAs by RT‐qPCR
In the validation phase, in order to confirm the results obtained from high‐throughput sequencing, four miRNAs that exhibited the highest degree of upregulation (miR‐215‐5p and miR‐378i, |log2fold change| >10, P<.01) and highest degree of downregulation (miR‐365b‐3p and miR‐135b‐5p, |log2fold change| >10, P<.01) in the patient group were selected as miRNA candidates for RT‐qPCR analysis in the validation cohorts, which included six patients with IgAN and six healthy controls.
RT‐qPCR analysis indicated that miR‐215‐5p and miR‐378i were indeed significantly upregulated, while miR‐365b‐3p and miR‐135b‐5p were significantly downregulated, in patients with IgAN compared with the healthy controls of validation cohorts; which was consistent with the high‐throughput sequencing analysis (Figure 6).
Figure 6.
Whisker‐Box plots showing the expression ratios of miRNAs by RT‐qPCR. Expression ratios in the immunoglobulin A nephropathy (IgAN) group were compared to the healthy control group by normalizing to RNU6. Ratios above one indicate that genes were upregulated in IgAN, while ratios below one indicate that genes were downregulated. MiR‐378i and miR‐215‐5p were significantly upregulated in the IgAN group vs the control group, and miR‐135b‐5p and miR‐365b‐3p were significantly downregulated in the IgAN group. The box‐whisker plots demarcate the range (whiskers), median (dotted line) and interquartile range (box) for each miRNA detected. The long whiskers refer to the high inter‐individual variance of expression
4. Discussion
Immunoglobulin A nephropathy is the most common type of primary glomerulonephritis in the world.1, 2 However, there is a lack of suitable biomarkers for the early diagnosis of IgAN. Urinary exosomes contain a stable source of miRNAs, making urine an appealing biological specimen to discover biomarkers for renal diseases.14, 24 In this study, we identified a number of differentially expressed exosomal miRNAs in the urine of patients with IgAN vs healthy controls using high‐throughput sequencing, followed by RT‐qPCR analysis, and propose that some exosomal miRNAs, miR‐29c, miR‐146a and miR‐205 may serve as biomarkers for IgAN.
The genome‐wide analysis of miRNA profiles in kidney biopsy tissues,25 peripheral blood mononuclear cells (PBMCs)18 and urine sediment26, 27 has identified multiple differentially expressed miRNAs in patients with IgAN vs healthy controls. However, these differentially expressed miRNAs identified in the above‐mentioned studies were not consistent with those identified in the present study, as shown in spreadsheets (Table S1). The different techniques and materials used in these studies may lead to inconsistencies. It is noteworthy to mention that compared with other clinical samples such as blood and kidney tissues, urinary exosomes have some obvious advantages in clinical tests, such as being non‐invasively collected and being easy to obtain. In contrast to renal biopsy, which only provides a small sample from the kidney, urinary exosomes provide the full representation of the entire urinary system.28 Furthermore, miRNAs in urine sediments are mostly of low‐quality, and are easy to degrade due to the high abundance of RNase in the kidneys, bladder and urinary tract. In contrast, intact miRNAs are abundant in urinary exosomes.24 As a result, high‐quality exosomal miRNAs in urine have been obtained in the present study.
To our knowledge, this study is the first to investigate the expression profiling of urinary exosomal miRNAs in patients with IgAN. We identified 158 differentially expressed miRNAs in urinary exosomes between patients with IgAN and healthy controls, in which 41 miRNAs were significantly and differentially expressed. Among these 41 miRNAs, miR‐29c, miR‐146a and miR‐205 have been reported to be involved in the pathogenesis and progression of IgAN.29 In our study, miR‐29c and miR‐205 were significantly downregulated, while miR‐146a was significantly upregulated in the urinary exosomes of patients with IgAN, compared with healthy controls; suggesting that miR‐29c, miR‐146a and miR‐205 in urinary exosomes may serve as biomarkers for IgAN. Among the 41 miRNAs, majority of the differentially expressed miRNAs have been found to be associated with other kidney diseases.
For example, miR‐215 plays critical roles in kidney development and differentiation,30 and is involved in promoting tubulointerstitial and renal glomerular fibrosis in diabetic nephropathy.31 MiR‐30e/UCP2 axis plays an important role in kidney fibrosis through mediating TGF‐β1‐induced epithelial‐mesenchymal transition (EMT).32 Therefore, miR‐215‐5P, miR‐30e‐3p and miR‐205 are most likely involved in the pathogenesis and progression of IgAN through mediating fibrosis and EMT in kidneys. In addition, the dysregulation of miR‐135b and miR‐135a leads to severe podocyte injury and the disorganization of the podocyte cytoskeleton in focal segmental glomerulosclerosis (FSGS).33 Thus, it is reasonable to propose that significantly downregulated miR‐135b‐5p, as shown in present study, may be related to the pathogenesis of IgAN. Furthermore, miR‐486 has been reported to coordinately protect against CKD‐induced muscle wasting in chronic kidney disease (CKD) through the downregulation of Forkhead transcription factors (FoxO1) and PTEN.34 The miR‐204/miR‐211‐Hmx1 signaling axis contributes to immune suppression in the host, leading to Candidemia‐induced kidney dysfunction.35 The overexpression of miR‐126 in the hematopoietic compartment is associated with stromal cell‐derived factor 1/CXCR4‐dependent vasculogenic progenitor cell mobilization; and thus, promotes vascular integrity and support the recovery of kidneys after ischemia/reperfusion injury (IRI) (Bijkerk et al., 2014). MiR‐708,36 miR‐27a37 and miR‐50938, 39 have been documented to be involved in cell apoptosis and proliferation in renal cell carcinoma. Based on the above‐mentioned studies, our findings suggest that miR‐708, miR‐27a and miR‐509 would likely exert effects on cell proliferation in kidney tissues in IgAN. The true roles of miRNAs in IgAN, as described above, remain to be investigated.
Nevertheless, there are a few limitations in our study. First, the sample size of patients and controls was relatively small. These findings should be validated in larger cohorts. Second, disease controls such as membranous nephropathy and minimal changes of the disease were not included in our study. Further studies are needed to confirm whether the four selected miRNAs (miR‐215‐5p, miR‐378i, miR‐365b‐3p and miR‐135b‐5p) are IgAN‐specific.
In summary, our study demonstrates for the first time a significant difference in urinary exosomal miRNA expression profiles between patients with IgAN and healthy controls. These exosomal miRNAs, such as miR‐29c, miR‐146a and miR‐205 may potentially serve as novel non‐invasive biomarkers for IgAN. The functional research of these miRNAs in IgAN may be a new interesting research area.
Supporting information
Acknowledgments
This work was supported by the National Natural Science Foundation of China (Grant No. 81360083, 81200091), the Youth Innovation Team of the Second Affiliated Hospital of Nanchang University (No. 2016YNTD12002), the Science and Technology Department of Jiangxi Province (No. 20143BBM26060, 20143BMM26054), and the Special Fund of Innovation for Graduate Students of Nanchang University (No. cx2015164).
Min Q‐H, Chen X‐M, Zou Y‐Q, et al. Differential expression of urinary exosomal microRNAs in IgA nephropathy. J Clin Lab Anal. 2018;32:e22226 10.1002/jcla.22226
Qing‐Hua Min, Xi‐Min Chen and Ye‐Qing Zou are joint first authors. Bo Huang and Xiao‐Zhong Wang are joint corresponding authors.
Contributor Information
Bo Huang, Email: 764019522@qq.com.
Xiao‐Zhong Wang, Email: wangxzlj@126.com.
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