Ferulic acid alleviates lipotoxicity-induced hepatocellular death through the SIRT1-regulated autophagy pathway and independently of AMPK and Akt in AML-12 hepatocytes

Tiantian Xu,Qianyu Qian,Xiangyao Wu,Qing Song,Songtao Li,Qiang Han,Hongzhi Pan,Li Zhou,Hui Chai,Wenwen Yang,Xiaobing Dou

doi:10.1186/s12986-021-00540-9

Abstract

BackgroundLipotoxicity-induced cell death plays a detrimental role in the pathogenesis of metabolic diseases. Ferulic acid, widespread in plant-based food, is a radical scavenger with multiple bioactivities. However, the benefits of ferulic acid against hepatic lipotoxicity are largely unclear. Here, we investigated the protective effect of ferulic acid against palmitate-induced lipotoxicity and clarified its potential mechanisms in AML-12 hepatocytes.MethodsAML-12 mouse hepatocytes were exposed to palmitate to mimic lipotoxicity. Different doses (25, 50, and 100 μM) of ferulic acid were added 2 h before palmitate treatment. Cell viability was detected by measuring lactate dehydrogenase release, nuclear staining, and the expression of cleaved-caspase-3. Intracellular reactive oxygen species content and mitochondrial membrane potential were analysed by fluorescent probes. The potential mechanisms were explored by molecular biological methods, including Western blotting and quantitative real-time PCR, and were further verified by siRNA interference.ResultsOur data showed that ferulic acid significantly inhibited palmitate-induced cell death, rescued mitochondrial membrane potential, reduced reactive oxygen species accumulation, and decreased inflammatory factor activation, including IL-6 and IL-1beta. Ferulic acid significantly stimulated autophagy in hepatocytes, whereas autophagy suppression blocked the protective effect of ferulic acid against lipotoxicity. Ferulic acid-activated autophagy, which was triggered by SIRT1 upregulation, was mechanistically involved in its anti-lipotoxicity effects. SIRT1 silencing blocked most beneficial changes induced by ferulic acid.ConclusionsWe demonstrated that the phytochemical ferulic acid, which is found in plant-based food, protected against hepatic lipotoxicity, through the SIRT1/autophagy pathway. Increased intake of ferulic acid-enriched food is a potential strategy to prevent and/or improve metabolic diseases with lipotoxicity as a typical pathological feature.

Highlights

Metabolic diseases, including non-alcoholic fatty liver disease (NAFLD), diabetes mellitus, and obesity, are a worldwide epidemic and commonly featureXu et al Nutr Metab (Lond) (2021) 18:13 hyperlipidaemia as a hallmark
Ferulic acid (FA) protects against hepatocyte cell death induced by Palmitate acid (PA) The cytotoxicity of FA was initially determined in AML12 hepatocytes
The results indicated that FA significantly suppressed PA-induced hepatocyte cell death in a dose-dependent manner (Fig. 1b, c)

Summary

Introduction

Metabolic diseases, including non-alcoholic fatty liver disease (NAFLD), diabetes mellitus, and obesity, are a worldwide epidemic and commonly featureXu et al Nutr Metab (Lond) (2021) 18:13 hyperlipidaemia as a hallmark. Because the liver is the central organ of metabolism, hepatic cell death induced by lipotoxicity accelerates the occurrence and development of metabolic diseases. We previously reported that alleviating hepatic lipotoxicity effectively improved high-fat-diet-induced NAFLD in mice [2]. Lipotoxicityinduced cell death is commonly induced by SFAs stimulating oxidative stress and endoplasmic reticulum stress [3, 4], whereas USFAs tend to improve SFA-induced lipotoxicity [5]. Palmitic acid (PA, C16:0) is the most abundant natural SFA in food and the human body and is widely used to induce lipotoxicity for scientific investigations [6, 7]. We investigated the protective effect of ferulic acid against palmitate-induced lipotoxicity and clarified its potential mechanisms in AML-12 hepatocytes

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