Role of peroxisome proliferator-activated receptors in non-alcoholic fatty liver disease inflammation

2018 ◽  
Vol 75 (16) ◽  
pp. 2951-2961 ◽  
Author(s):  
Amanda Karolina Soares Silva ◽  
Christina Alves Peixoto
2017 ◽  
Vol 67 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Xin Sun ◽  
Yan Zhang ◽  
Meilin Xie

AbstractNon-alcoholic fatty liver disease (NAFLD) has been defined as a spectrum of histological abnormalities and is characterized by significant and excessive accumulation of triglycerides in the hepatocytes in patients without alcohol consumption or other diseases. Current studies are targeting new molecular mechanisms that underlie NAFLD and associated metabolic disorders. Many therapeutic targets have been found and used in clinical studies. Peroxisome proliferator-activated receptors (PPARs) are among the potential targets and have been demonstrated to exert a pivotal role in modulation of NAFLD. Many drugs developed so far are targeted at PPARs. Thus, the aim of this paper is to summarize the roles of PPARs in the treatment of NAFLD.


Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1638 ◽  
Author(s):  
Anne Fougerat ◽  
Alexandra Montagner ◽  
Nicolas Loiseau ◽  
Hervé Guillou ◽  
Walter Wahli

Non-alcoholic fatty liver disease (NAFLD) is a major health issue worldwide, frequently associated with obesity and type 2 diabetes. Steatosis is the initial stage of the disease, which is characterized by lipid accumulation in hepatocytes, which can progress to non-alcoholic steatohepatitis (NASH) with inflammation and various levels of fibrosis that further increase the risk of developing cirrhosis and hepatocellular carcinoma. The pathogenesis of NAFLD is influenced by interactions between genetic and environmental factors and involves several biological processes in multiple organs. No effective therapy is currently available for the treatment of NAFLD. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that regulate many functions that are disturbed in NAFLD, including glucose and lipid metabolism, as well as inflammation. Thus, they represent relevant clinical targets for NAFLD. In this review, we describe the determinants and mechanisms underlying the pathogenesis of NAFLD, its progression and complications, as well as the current therapeutic strategies that are employed. We also focus on the complementary and distinct roles of PPAR isotypes in many biological processes and on the effects of first-generation PPAR agonists. Finally, we review novel and safe PPAR agonists with improved efficacy and their potential use in the treatment of NAFLD.


2021 ◽  
Vol 10 (5) ◽  
pp. 1081
Author(s):  
Mikkel Parsberg Werge ◽  
Adrian McCann ◽  
Elisabeth Douglas Galsgaard ◽  
Dorte Holst ◽  
Anne Bugge ◽  
...  

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing and approximately 25% of the global population may have NAFLD. NAFLD is associated with obesity and metabolic syndrome, but its pathophysiology is complex and only partly understood. The transsulfuration pathway (TSP) is a metabolic pathway regulating homocysteine and cysteine metabolism and is vital in controlling sulfur balance in the organism. Precise control of this pathway is critical for maintenance of optimal cellular function. The TSP is closely linked to other pathways such as the folate and methionine cycles, hydrogen sulfide (H2S) and glutathione (GSH) production. Impaired activity of the TSP will cause an increase in homocysteine and a decrease in cysteine levels. Homocysteine will also be increased due to impairment of the folate and methionine cycles. The key enzymes of the TSP, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), are highly expressed in the liver and deficient CBS and CSE expression causes hepatic steatosis, inflammation, and fibrosis in animal models. A causative link between the TSP and NAFLD has not been established. However, dysfunctions in the TSP and related pathways, in terms of enzyme expression and the plasma levels of the metabolites (e.g., homocysteine, cystathionine, and cysteine), have been reported in NAFLD and liver cirrhosis in both animal models and humans. Further investigation of the TSP in relation to NAFLD may reveal mechanisms involved in the development and progression of NAFLD.


Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 687
Author(s):  
Daniela Gabbia ◽  
Luana Cannella ◽  
Sara De De Martin

A peculiar role for oxidative stress in non-alcoholic fatty liver disease (NAFLD) and its transition to the inflammatory complication non-alcoholic steatohepatitis (NASH), as well as in its threatening evolution to hepatocellular carcinoma (HCC), is supported by numerous experimental and clinical studies. NADPH oxidases (NOXs) are enzymes producing reactive oxygen species (ROS), whose abundance in liver cells is closely related to inflammation and immune responses. Here, we reviewed recent findings regarding this topic, focusing on the role of NOXs in the different stages of fatty liver disease and describing the current knowledge about their mechanisms of action. We conclude that, although there is a consensus that NOX-produced ROS are toxic in non-neoplastic conditions due to their role in the inflammatory vicious cycle sustaining the transition of NAFLD to NASH, their effect is controversial in the neoplastic transition towards HCC. In this regard, there are indications of a differential effect of NOX isoforms, since NOX1 and NOX2 play a detrimental role, whereas increased NOX4 expression appears to be correlated with better HCC prognosis in some studies. Further studies are needed to fully unravel the mechanisms of action of NOXs and their relationships with the signaling pathways modulating steatosis and liver cancer development.


Gut ◽  
2020 ◽  
pp. gutjnl-2020-321767
Author(s):  
Marta B Afonso ◽  
Pedro M Rodrigues ◽  
Miguel Mateus-Pinheiro ◽  
André L Simão ◽  
Maria M Gaspar ◽  
...  

ObjectiveReceptor-interacting protein kinase 3 (RIPK3) is a key player in necroptosis execution and an emerging metabolic regulator, whose contribution to non-alcoholic fatty liver disease (NAFLD) is controversial. We aimed to clarify the impact of RIPK3 signalling in the pathogenesis of human and experimental NAFLD.DesignRIPK3 levels were evaluated in two large independent cohorts of patients with biopsy proven NAFLD diagnosis and correlated with clinical and biochemical parameters. Wild-type (WT) or Ripk3-deficient (Ripk3−/−) mice were fed a choline-deficient L-amino acid-defined diet (CDAA) or an isocaloric control diet for 32 and 66 weeks.ResultsRIPK3 increased in patients with non-alcoholic steatohepatitis (NASH) in both cohorts, correlating with hepatic inflammation and fibrosis. Accordingly, Ripk3 deficiency ameliorated CDAA-induced inflammation and fibrosis in mice at both 32 and 66 weeks. WT mice on the CDAA diet for 66 weeks developed preneoplastic nodules and displayed increased hepatocellular proliferation, which were reduced in Ripk3−/− mice. Furthermore, Ripk3 deficiency hampered tumourigenesis. Intriguingly, Ripk3−/− mice displayed increased body weight gain, while lipidomics showed that deletion of Ripk3 shifted hepatic lipid profiles. Peroxisome proliferator-activated receptor γ (PPARγ) was increased in Ripk3−/− mice and negatively correlated with hepatic RIPK3 in patients with NAFLD. Mechanistic studies established a functional link between RIPK3 and PPARγ in controlling fat deposition and fibrosis.ConclusionHepatic RIPK3 correlates with NAFLD severity in humans and mice, playing a key role in managing liver metabolism, damage, inflammation, fibrosis and carcinogenesis. Targeting RIPK3 and its intricate signalling arises as a novel promising approach to treat NASH and arrest disease progression.


2017 ◽  
Vol 23 (10) ◽  
pp. 1881 ◽  
Author(s):  
Shira Zelber-Sagi ◽  
Shiran Bord ◽  
Gali Dror-Lavi ◽  
Matthew Lee Smith ◽  
Samuel D Towne Jr ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1822
Author(s):  
Christian von Loeffelholz ◽  
Sina M. Coldewey ◽  
Andreas L. Birkenfeld

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.


Sign in / Sign up

Export Citation Format

Share Document