DataSheet2_Zebrafish cobll1a regulates lipid homeostasis via the RA signaling pathway.ZIP

Background:The COBLL1 gene has been implicated in human central obesity, fasting insulin levels, type 2 diabetes, and blood lipid profiles. However, its molecular mechanisms remain largely unexplored.
Methods:In this study, we established cobll1a mutant lines using the CRISPR/Cas9-mediated gene knockout technique. To further dissect the molecular underpinnings of cobll1a during early development, transcriptome sequencing and bioinformatics analysis was employed.
Results:Our study showed that compared to the control, cobll1a−/− zebrafish embryos exhibited impaired development of digestive organs, including the liver, intestine, and pancreas, at 4 days post-fertilization (dpf). Transcriptome sequencing and bioinformatics analysis results showed that in cobll1a knockout group, the expression level of genes in the Retinoic Acid (RA) signaling pathway was affected, and the expression level of lipid metabolism-related genes (fasn, scd, elovl2, elovl6, dgat1a, srebf1 and srebf2) were significantly changed (p < 0.01), leading to increased lipid synthesis and decreased lipid catabolism. The expression level of apolipoprotein genes (apoa1a, apoa1b, apoa2, apoa4a, apoa4b, and apoea) genes were downregulated.
Conclusion:Our study suggest that the loss of cobll1a resulted in disrupted RA metabolism, reduced lipoprotein expression, and abnormal lipid transport, therefore contributing to lipid accumulation and deleterious effects on early liver development.

背景：COBLL1基因与人类中枢性肥胖、空腹胰岛素水平、2型糖尿病及血脂谱密切相关，但其分子机制目前尚未得到充分阐明。
方法：本研究采用CRISPR/Cas9介导的基因敲除技术构建了cobll1a突变体品系；为进一步解析cobll1a在早期发育过程中的分子基础，本研究运用转录组测序与生物信息学分析手段开展研究。
结果：本研究显示，与对照组相比，受精后4天（dpf）的cobll1a−/−斑马鱼胚胎出现肝脏、肠道及胰腺等消化器官发育受损的表型。转录组测序及生物信息学分析结果表明，在cobll1a基因敲除组中，视黄酸（Retinoic Acid, RA）信号通路相关基因的表达水平受到干扰；同时，脂代谢相关基因（fasn、scd、elovl2、elovl6、dgat1a、srebf1及srebf2）的表达水平发生显著变化（p < 0.01），最终导致脂质合成增加、脂质分解减少。载脂蛋白基因（apoa1a、apoa1b、apoa2、apoa4a、apoa4b及apoea）的表达水平均出现下调。
结论：本研究表明，cobll1a的缺失会引发视黄酸代谢紊乱、脂蛋白表达降低及脂质转运异常，进而造成脂质蓄积并对肝脏早期发育产生不利影响。