Li Jin1, Heng Gao2, JiuPing Wang3, ShuJuan Yang4, Jing Wang1, JingFeng Liu1,5, Yuan Yang1,5, TaoTao Yan1,5, Tianyan Chen1,5, Yingren Zhao1,5, Yingli He1,5. 1. Institution of Hepatology, First Affiliated Teaching Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an City, Shaanxi province, China. 2. Xi'an Health School, Xi'an City, Shaanxi province, China. 3. Centre of Liver Diseases, Fourth Military Medical University, First Affiliated Teaching Hospital, Xi'an City, Shaanxi, China. 4. Xi'an Eighth Hospital Affiliated to Xi'an Jiaotong University, Xi'an City, Shaanxi province, China. 5. Department of Infectious Diseases, First Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an City, Shaanxi province, China.
Abstract
BACKGROUND & AIMS: We previously found that hepatic stellate cell activation induced by autophagy maintains the liver architecture to prevent collapse during acute liver failure. Nitric oxide has shown to induce hepatic stellate cell apoptosis. Whether and how nitric oxide is involved in acute liver failure and autophagy remains unclear. METHODS: Acute liver failure patients were recruited to investigate the correlation between plasma nitric oxide levels and clinical features. Liver tissues were collected from chronic hepatitis patients by biopsy and from acute liver failure patients who had undergone liver transplantation. The expression of nitric oxide synthases and hepatic stellate cell activation (alpha-SMA), and autophagic activity (LC3) were investigated by immunohistochemistry. Autophagy and apoptosis were investigated by immunoblot analysis, confocal microscopy, and flow cytometry in hepatic stellate cells treated with nitric oxide donors. RESULTS: Plasma nitric oxide level was significantly increased in patients with acute liver failure compared to those with cirrhosis (53.60±19.74 μM vs 19.40±9.03 μM, Z=-7.384, P<.001) and positively correlated with MELD-Na score (r=.539, P<.001), implicating nitric oxide in acute liver failure. At least some Nitric oxide was produced by overexpression of inducible nitric oxide synthases and endothelial nitric oxide synthases, but not neuronal nitric oxide synthases in the liver tissue. In vivo observation revealed that autophagy was inhibited in hepatic stellate cells based on decreased LC3 immunostaining, and in vitro experiments demonstrated that Nitric oxide can inhibit autophagy. Moreover, nitric oxide promoted hepatic stellate cell apoptosis, which was rescued by an autophagy inducer. CONCLUSIONS: Increased nitric oxide synthases/ nitric oxide promotes apoptosis through autophagy inhibition in hepatic stellate cells during acute liver failure, providing a novel strategy for the treatment of patients with acute liver failure.
BACKGROUND & AIMS: We previously found that hepatic stellate cell activation induced by autophagy maintains the liver architecture to prevent collapse during acute liver failure. Nitric oxide has shown to induce hepatic stellate cell apoptosis. Whether and how nitric oxide is involved in acute liver failure and autophagy remains unclear. METHODS:Acute liver failurepatients were recruited to investigate the correlation between plasma nitric oxide levels and clinical features. Liver tissues were collected from chronic hepatitispatients by biopsy and from acute liver failurepatients who had undergone liver transplantation. The expression of nitric oxide synthases and hepatic stellate cell activation (alpha-SMA), and autophagic activity (LC3) were investigated by immunohistochemistry. Autophagy and apoptosis were investigated by immunoblot analysis, confocal microscopy, and flow cytometry in hepatic stellate cells treated with nitric oxide donors. RESULTS: Plasma nitric oxide level was significantly increased in patients with acute liver failure compared to those with cirrhosis (53.60±19.74 μM vs 19.40±9.03 μM, Z=-7.384, P<.001) and positively correlated with MELD-Na score (r=.539, P<.001), implicating nitric oxide in acute liver failure. At least some Nitric oxide was produced by overexpression of inducible nitric oxide synthases and endothelial nitric oxide synthases, but not neuronal nitric oxide synthases in the liver tissue. In vivo observation revealed that autophagy was inhibited in hepatic stellate cells based on decreased LC3 immunostaining, and in vitro experiments demonstrated that Nitric oxide can inhibit autophagy. Moreover, nitric oxide promoted hepatic stellate cell apoptosis, which was rescued by an autophagy inducer. CONCLUSIONS: Increased nitric oxide synthases/ nitric oxide promotes apoptosis through autophagy inhibition in hepatic stellate cells during acute liver failure, providing a novel strategy for the treatment of patients with acute liver failure.
Authors: YiMin Zhang; Li Shao; Ning Zhou; JianZhou Li; Yu Chen; Juan Lu; Jie Wang; ErMei Chen; ZhongYang Xie; LanJuan Li Journal: Can J Gastroenterol Hepatol Date: 2018-04-12