Salt induces hepatic inflammatory response through epigenetic modulation of SIRT3 [RNA-seq]

Purpose: Although clinical evidence suggests that high salt intake is associated with NAFLD, the underlying mechanism remains elusive. We sought to investigate whether salt-induced inflammation in liver is dependent on SIRT3 reduction. Methods: 6-week-old male SIRT3 knockout or their wild-type littermates were fed with high salt diet (HSD, containing 8% NaCl) or normal salt diet (NSD, containing 0.4% NaCl) for 4 months. And then their liver tissues were removed and total RNA was extracted to perform RNA sequencing. Results: 1850 differentially upregulated expressed genes were identified when comparing HSD group (HSD1, HSD2) to NSD group (NSD WT1, NSD2). Meanwhile, 1246 differentially upregulated expressed genes in response to SIRT3 knockout were determined (each group containing 3 samples). we observed that the common genes upregulated by both HSD and knockout of SIRT3 were enriched in immune system, including Tnf, Ccl2, etc. In addition, the common genes upregulated by knockout of SIRT3 in both NSD and HSD group were still enriched in the immune system. Conclusions: Through RNA-seq, we determined that HSD-induced hepatic inflammation was highly similar to the effect of SIRT3 knockout, suggesting that reduction of SIRT3 expression is the main reason leading to salt-induced hepatic inflammation. Including 15 samples, liver mRNA profiles of SIRT3 knockout (KO) or wild-type (WT) mice fed with high salt diet (HSD) or normal salt diet (NSD) for 4 months.研究目的：尽管临床证据显示高盐摄入与非酒精性脂肪性肝病（NAFLD）存在关联，但其潜在机制仍不明晰。本研究旨在探讨盐诱导的肝脏炎症是否依赖于沉默信息调节因子3（SIRT3）的表达降低。方法：选取6周龄的雄性SIRT3敲除（KO）小鼠及其野生型（WT）同窝对照小鼠，分别喂食高盐饲料（HSD，氯化钠含量为8%）或正常盐饲料（NSD，氯化钠含量为0.4%），持续饲养4个月。随后摘取肝脏组织，提取总RNA并进行RNA测序（RNA-seq）。结果：将高盐组（HSD1、HSD2）与正常盐野生型组（NSD WT1、NSD2）进行对比，共鉴定出1850个差异上调表达基因。同时，针对SIRT3敲除组，我们确定了1246个差异上调表达基因（每组包含3个样本）。研究发现，高盐饲料处理与SIRT3敲除共同上调的共有基因显著富集于免疫系统通路，包括肿瘤坏死因子（Tnf）、趋化因子配体2（Ccl2）等。此外，在正常盐饲料与高盐饲料饲养条件下，SIRT3敲除所共同上调的共有基因仍显著富集于免疫系统通路。结论：通过RNA-seq分析，本研究证实高盐饲料诱导的肝脏炎症与SIRT3敲除产生的效应高度相似，提示SIRT3表达降低是盐诱导肝脏炎症的主要诱因。本数据集包含15个样本，为喂食高盐饲料（HSD）或正常盐饲料（NSD）4个月的SIRT3敲除（KO）或野生型（WT）小鼠的肝脏mRNA表达谱。