2024(5):615-625.
DOI: 10.7655/NYDXBNSN231186
Abstract:
Objective：To explore the role and mechanism of heat shock protein A12A（HSPA12A）in hepatic injury induced by endotoxemia. Methods：①The mRNA expression changes of Hspa12a and multiple apolipoproteins were analyzed by bioinformatics using a public database of RNA sequencing results from septic mice liver tissue. ② Endotoxemia was induced by intraperitoneal injection of lipopolysaccharide（LPS，5 mg/kg）using 6-8-week -old Hspa12a knockout（Hspa12a-/-）mice and wild -type（WT）mice. Mice treated with normal saline（NS）served as controls. Animals were divided into four groups，NS-WT group，NS-Hspa12a-/- group， LPS-WT group，and LPS-Hspa12a-/- group. Six hours after LPS treatment，liver tissues were collected to evaluate the tissue damage by HE and analyze the expression levels of HSPA12A，ApoA1，ApoB，and ApoM by immunoblotting and RT-PCR. Serum was separated for measuring the levels of liver function markers（alanine aminotransferase，ALT；aspartate aminotransferase，AST）and lipoproteins （high-density lipoprotein cholesterol，HDL-C；low-density lipoprotein cholesterol，LDL-C）. ③Primary hepatocytes overexpressed Hspa12a were treated with LPS（500 ng/mL）to emulate endotoxemia induced liver injury. Six hours after LPS treatment，culture medium was collected for measuring levels of ALT and AST. ④Patients were divided into the sepsis induced liver injury group and the control group according to whether the septic liver injury occurred. ALT，AST，HDL-C and LDL-C levels were collected and compared between the two groups. Results：①Bioinformatic analysis showed that the levels of Hspa12a，Apoa1，Apob and Apom mRNA were decreased in livers of septic mice. ②Compared with NS -WT mice，LPS -WT mice displayed obvious histopathological injury in liver tissues（P < 0.001）and the number of inflammatory foci was increased（P < 0.01）along with the elevated serum ALT（P < 0.05）and AST（P < 0.01）activiaties. At the same time，the expression of HSPA12A protein in liver was decreased（P < 0.05）. However， compared with LPS -WT mice，LPS -Hspa12a-/- mice showed more severe pathological damage of liver tissues（P < 0.05），along with higher ALT（P < 0.01）and AST（P < 0.05）levels and lower HDL-C and LDL-C levels（P < 0.01）. At the same time，the expression levels of hepatic apolipoproteins（ApoA1，ApoB，ApoM）were reduced（P < 0.05，P < 0.01）. ③In vitro，ALT and AST levels in culture medium of hepatocytes were signaficantly increased after LPS treatment（P < 0.001）. However，overexpression of Hspa12a alleviated the increases of ALT and AST levels（P < 0.01）. ④Clinical results suggested that compared with the control group，the sepsis induced liver injury group showed signaficantly higher serum ALT and AST levels（P < 0.001）. In contrast，HDL -C and LDL -C levels were signaficantly lower（P < 0.001）. Conclusion：Endotoxemia leads to downregulation of hepatic HSPA12A expression，which mediates the development of endotoxemic liver injury. However，overexpression of Hspa12a can protect liver injury induced by endotoxemia. The action of HSPA12A may involve the regulation of hepatic apolipoprotein expression and serum lipoprotein cholesterol levels.
