Table 1.
FXR-dependent changes induced by GSPE in the hepatic expression of lipid and lipoprotein related genes.
| Genebank ID | Gene name; symbol | fold change upon GSPE treatment | SREBP1 target | |
|---|---|---|---|---|
| FA and TG synthesis and metabolism | WT | FXR−/− | ||
| NM_011480 | sterol regulatory element binding factor 1;Srebf1 (SREBP1) * | 0.7 | 1.0 | [53] |
| 0.6 | 1.0 | |||
| NM_019811 | acyl-CoA synthetase short-chain family member 2; Acss2/Acsl1 * | 0.6 | 0.9 | [33] |
| NM_146197 | acyl-CoA synthetase medium-chain family member 2; Acsm2 * | 0.6 | 0.8 | |
| NM_009127 | stearoyl-Coenzyme A desaturase 1; Scd1 | 0.6 | 1.1 | [34] |
| NM_009128 | stearoyl-Coenzyme A desaturase 2; Scd2 * | 0.7 | 1.0 | |
| NM_028089 | cytochrome P450, family 2, subfamily c, polypeptide 55; Cyp2c55 * | 0.6 | 1.0 | |
| NM_175443 | ethanolamine kinase 2; Etnk2 * | 0.7 | 0.9 | |
| NM_008903 | phosphatidic acid phosphatase 2a; Ppap2a * | 0.6 | 0.8 | |
| NM_008846 | phosphatidylinositol-4-phosphate 5-kinase, type 1 alpha; Pip5k1a | 0.7 | 0.9 | |
| NM_008845 | phosphatidylinositol-4-phosphate 5-kinase, type II, alpha; Pip5k2a * | 0.7 | 0.9 | |
| NM_207683 | phosphatidylinositol 3-kinase, C2 domain containing, gamma polypeptide; Pik3c2g | 0.7 | 1.0 | |
| NM_013490 | choline kinase alpha; Chka * | 0.7 | 0.8 | |
| NM_019677 | phospholipase C, beta 1; Plcb1 | 0.7 | 1.0 | |
| NM_080434 | Apolipoprotein A5; ApoA5 * | 1.4 | 1.0 | [36] |
| 1.7 | 1.0 | |||
| Cholesterol Biosynthesis | ||||
| NM_145942 | 3-hydroxy-3-methylglutaryl-Coenzyme A synthase 1; Hmgcs1 * | 0.7 | 0.9 | [39, 42] |
| NM_008255 | 3-hydroxy-3-methylglutaryl-Coenzyme A reductase; Hmgcr * | 0.7 | 0.8 | |
| NM_023556 | mevalonate kinase; Mvk * | 0.7 | 0.9 | |
| NM_026784 | phosphomevalonate kinase; Pmvk * | 0.7 | 0.9 | |
| NM_138656 | mevalonate (diphospho) decarboxylase; Mvd | 0.7 | 0.9 | |
| NM_134469 | farnesyl diphosphate synthetase; Fdps * | 0.7 | 0.9 | |
| NM_010941 | NAD(P) dependent steroid dehydrogenase-like; Nsdhl * | 0.7 | 0.9 | |
| NM_172769 | sterol-C5-desaturase ; Sc5d * | 0.7 | 0.9 | |
| NM_007856 | 7-dehydrocholesterol reductase; Dhcr7 * | 0.7 | 0.9 | |
| Other lipid-related | ||||
| NM_009883 | CCAAT/enhancer binding protein (C/EBP), beta; Cebpb * | 0.7 | 0.9 | [37] |
| NM_013634 | peroxisome proliferator activated receptor binding protein; Pparbp * | 0.7 | 1.0 | |
| NM_011374 | ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1; St8sia1 | 0.7 | 0.9 | |
| NM_018784 | ST3 beta-galactoside alpha-2,3-sialyltransferase 6; St3gal6 * | 0.7 | 1.3 | |
| NM_011372 | ST6 (alpha-N-acetyl-neuraminyl-2,3-beta-galactosyl-1,3)-N-acetylgalactosaminide alpha-2,6-sialyltransferase 3; St6galnac3 | 0.7 | 0.9 | |
| NM_018830 | N-acylsphingosine amidohydrolase 2; Asah2 | 0.5 | 1.2 | |
| NM_153389 | ATPase, Class V, type 10D; Atp10d | 0.7 | 1.0 | |
| NM_028057 | cytochrome b5 reductase 1; Cyb5r1 * | 0.7 | 1.5 | |
| NM_012054 | acyloxyacyl hydrolase; Aoah | 0.6 | 1.0 | |
Wild type and FXR−/− mice (n=5 in each treatment group, 8–10 weeks old) were fed two doses of either vehicle or GSPE (250 mg/Kg), separated by a 12 h time lapse, as described in Materials and Methods. Two hours after the second gavage, liver total RNA from the 4 groups was obtained and pooled. Microarray data was obtained by comparing gene expression of WT control versus WT GSPE-treated mice and FXR−/− control versus FXR−/− GSPE-treated mice. The whole microarray fold-changes were processed using Panther software in order to identify FXR-dependent changes induced by GSPE in genes clustered in the “Lipid, fatty acid and steroid metabolism” metabolic pathway. ApoA5 and CEBP/β are not included in this cluster by Panther software and were added separately. Fold-change thresholds were fixed as 0.7 and 1.5 for down-regulation and up-regulation respectively. Real time quantitative PCR was performed with selected genes to confirm the microarray data (shown in bold characters). Selected references are given for known SREBP1 target genes. Asterisks highlight those genes previously found to be responsive to GSPE in a SHP-dependent way [16]. WT column: fold-change in expression induced by GSPE in wild-type mice relative to the expression in wild type mice treated with vehicle. FXR−/− column: fold-change in expression induced by GSPE in FXR−/− mice relative to the expression in FXR−/− mice treated with vehicle only.