Perilipin 5 alleviates HCV NS5A-induced lipotoxic injuries in liver
Perilipin 5 alleviates HCV NS5A-induced lipotoxic injuries in liver
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Perilipin 5 减轻 HCV NS5A 诱导的肝脏脂毒性损伤
DOI：
10.1186/s12944-019-1022-7
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发表时间：
2019
影响因子：
4.5
通讯作者：
Ye Jing
中科院分区：
文献类型：
--
作者：
Zhang Jin;Gao Xing;Yuan Yuan;Sun Chao;Zhao Yuanlin;Xiao Liming;Yang Ying;Gu Yu;Yang Risheng;Hu Peizhen;Zhang Lijun;Wang Chao;Ye Jing
研究背景脂滴（lipid droplets，LD）的稳态在维持细胞内的生理代谢过程中起着重要作用，并受到许多LD相关蛋白的调节，其中包括肝脏中的围脂蛋白5（perilipin 5，Plin 5）。LDs作为丙型肝炎病毒（HCV）病毒粒子的装配位点，在病毒感染过程中起着重要作用.此外，肝LD代谢可以被干扰的非结构性HCV蛋白，如NS 5A，但细节仍然是inexplicit.MethodsHCV NS 5A过表达的野生型和Plin 5-null小鼠的肝脏和肝细胞。采用BODIPY 493/503和油红O染色法检测小鼠肝脏和肝细胞脂质含量。进一步测定脂质、脂质过氧化和炎症生物标志物的水平。结果腺病毒感染后1周，表达NS 5A的Plin 5基因敲除小鼠肝脏炎性细胞聚集明显增多，肝组织损伤程度加重，与血清IL-2和TNF-α水平升高相一致（P<0. 05）。肝脏和肝细胞中Plin 5的缺失加重了NS 5A表达引起的MDA和4-HNE水平的升高（P< 0.01）。在野生型肝脏和肝细胞中，NS 5A表达使甘油三酯（TG）含量增加约25%，但在Plin 5缺失的肝脏和肝细胞中没有变化。更重要的是，肝脏和肝细胞中Plin 5缺陷加剧了由NS 5A表达刺激的非酯化脂肪酸（NEFA）的升高（分别为P< 0.05和0.01）。利用三酸甘油酯C阻断酰基辅酶A的合成，我们发现Plin 5缺陷加重了NS 5A诱导的TG脂解。相反，在HepG 2细胞中Plin 5过表达改善了NS 5A诱导的脂肪分解和脂毒性损伤。免疫荧光染色表明，NS 5A的表达刺激了Plin 5的靶向肝细胞中的LD的表面，而不改变Plin 5的蛋白水平。结论Plin 5对HCV NS 5A诱导的肝脂毒性损伤具有保护作用，这对深入了解HCV感染时肝脏的脂肪变性和损伤具有重要意义。
BackgroundThe homeostasis of lipid droplets (LDs) plays a crucial role in maintaining the physical metabolic processes in cells, and is regulated by many LD-associated proteins, including perilipin 5 (Plin5) in liver. As the putative sites of hepatitis C virus (HCV) virion assembly, LDs are vital to viral infection. In addition, the hepatic LD metabolism can be disturbed by non-structural HCV proteins, such as NS5A, but the details are still inexplicit.MethodsHCV NS5A was overexpressed in the livers and hepatocytes of wild-type andPlin5-null mice. BODIPY 493/503 and oil red O staining were used to detect the lipid content in mouse livers and hepatocytes. The levels of lipids, lipid peroxidation and inflammation biomarkers were further determined. Immunofluorescence assay and co-immunoprecipitation assay were performed to investigate the relationship of Plin5 and NS5A.ResultsOne week after adenovirus injection, livers expressing NS5A showed more inflammatory cell aggregation and more severe hepatic injuries inPlin5-null mice than in control mice, which was consistent with the increased serum levels of IL-2 and TNF-α (P< 0.05) observed inPlin5-null mice. Moreover, Plin5 deficiency in the liver and hepatocytes aggravated the elevation of MDA and 4-HNE levels induced by NS5A expression (P< 0.01). The triglyceride (TG) content was increased approximately 25% by NS5A expression in the wild-type liver and hepatocytes but was unchanged in thePlin5-null liver and hepatocytes. More importantly, Plin5 deficiency in the liver and hepatocytes exacerbated the elevation of non-esterified fatty acids (NEFAs) stimulated by NS5A expression (P< 0.05 and 0.01 respectively). Using triacsin C to block acyl-CoA biosynthesis, we found that Plin5 deficiency aggravated the NS5A-induced lipolysis of TG. In contrast, Plin5 overexpression in HepG2 cells ameliorated the NS5A-induced lipolysis and lipotoxic injuries. Immunofluorescent staining demonstrated that NS5A expression stimulated the targeting of Plin5 to the surface of the LDs in hepatocytes without altering the protein levels of Plin5. By co-IP, we found that the N-terminal domain (aa 32–128) of Plin5 was pivotal for its binding with NS5A.ConclusionsOur data highlight a protective role of Plin5 against hepatic lipotoxic injuries induced by HCV NS5A, which is helpful for understanding the steatosis and injuries in liver during HCV infection.