Endogenous catalase delays high-fat diet-induced liver injury in mice

Lingjuan Piao,Jiyeon Choi,Guideock Kwon,Hunjoo Ha 대한생리학회-대한약리학회 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease in parallel with worldwide epidemic of obesity. Reactive oxygen species (ROS) contributes to the development and progression of NAFLD. Peroxisomes play an important role in fatty acid oxidation and ROS homeostasis, and catalase is an antioxidant exclusively expressed in peroxisome. The present study examined the role of endogenous catalase in early stage of NAFLD. 8-week-old male catalase knock-out (CKO) and age-matched C57BL/6J wild type (WT) mice were fed either a normal diet (ND: 18% of total calories from fat) or a high fat diet (HFD: 60% of total calories from fat) for 2 weeks. CKO mice gained body weight faster than WT mice at early period of HFD feeding. Plasma triglyceride and ALT, fasting plasma insulin, as well as liver lipid accumulation, inflammation (F4/80 staining), and oxidative stress (8-oxo-dG staining and nitrotyrosine level) were significantly increased in CKO but not in WT mice at 2 weeks of HFD feeding. While phosphorylation of Akt (Ser473) and PGC1α mRNA expression were decreased in both CKO and WT mice at HFD feeding, GSK3β phosphorylation and Cox4-il mRNA expression in the liver were decreased only in CKO-HF mice. Taken together, the present data demonstrated that endogenous catalase exerted beneficial effects in protecting liver injury including lipid accumulation and inflammation through maintaining liver redox balance from the early stage of HFD-induced metabolic stress.

Endogenous catalase delays high-fat diet-induced liver injury in mice

Piao, Lingjuan,Choi, Jiyeon,Kwon, Guideock,Ha, Hunjoo The Korean Society of Pharmacology 2017 The Korean Journal of Physiology & Pharmacology Vol.21 No.3

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent liver disease in parallel with worldwide epidemic of obesity. Reactive oxygen species (ROS) contributes to the development and progression of NAFLD. Peroxisomes play an important role in fatty acid oxidation and ROS homeostasis, and catalase is an antioxidant exclusively expressed in peroxisome. The present study examined the role of endogenous catalase in early stage of NAFLD. 8-week-old male catalase knock-out (CKO) and age-matched C57BL/6J wild type (WT) mice were fed either a normal diet (ND: 18% of total calories from fat) or a high fat diet (HFD: 60% of total calories from fat) for 2 weeks. CKO mice gained body weight faster than WT mice at early period of HFD feeding. Plasma triglyceride and ALT, fasting plasma insulin, as well as liver lipid accumulation, inflammation (F4/80 staining), and oxidative stress (8-oxo-dG staining and nitrotyrosine level) were significantly increased in CKO but not in WT mice at 2 weeks of HFD feeding. While phosphorylation of Akt (Ser473) and $PGC1{\alpha}$ mRNA expression were decreased in both CKO and WT mice at HFD feeding, $GSK3{\beta}$ phosphorylation and Cox4-il mRNA expression in the liver were decreased only in CKO-HF mice. Taken together, the present data demonstrated that endogenous catalase exerted beneficial effects in protecting liver injury including lipid accumulation and inflammation through maintaining liver redox balance from the early stage of HFD-induced metabolic stress.

RESEARCH PAPER A novel plasminogen activator inhibitor-1 inhibitor, TM5441, protects against high-fat diet-induced obesity and adipocyte injury in mice

( Lingjuan Piao ),( Inji Jung ),( Joo Young Huh ),( Toshio Miyata ),( Hunjoo Ha ) 전남대학교 약품개발연구소 2016 약품개발연구지 Vol.25 No.-

BACKGROUND AND PURPOSE Obesity is one of the most prevalent chronic diseases worldwide, and dysregulated adipocyte function plays an important role in Obesity-associated metabolic disorder. The level of plasma plasminogen activator inhibitor-1 (PAI-1) is increased in obese subjucts, and PAI-1 null mice show improved insulin sensitivity when subjected to high-fat and high-sucrose diet-induced metabolic stress, suggesting that a best-in-class PAI-1 inhibitor may become a novel therapeutic agent for obesity-associated metabolic syndrome. TM5441 is a novel orally active PAI-1 inhibitor that does not cause bleeding episodes. Hence, in the present study we examined the preventive effect of TM5441 on high-fat diet (HFD)-induced adipocyte dysfunction. EXPERIMENTAL APPROACH Ten-week-old C57BL/6J mice were fed a normal diet (18% of total calories from fat) or HFD (60% of total calories from fat) for 10 weeks, and TM5441 (20mgㆍkg^-1 oral gavage) was administered daily with the initiation of HFD. KEY RESULTS TM5441 prevented HFD-induced body weight gain and systemic insulin resistance. TM5441 normalized HFD-induced dysregu-lated JNK and Akt phosphorylation, suggesting that it prevents the insulin resistance of adipocytes. TM5441 also attenuated the macrophage infiltration and increased expression of pro-inflammatory cytokines, such as inducible nitric oxide synthase, induced by the HFD. In addition TM5441 prevented the HFD-induced down-regulation of genes involved in mitochondrial biogenesis and function, suggesting that it may prevent adipocyte inflammation and dysregulation by maintaining mitochondrial fitness. CONCLUSION AND IMPLICATIONS Our data suggest that TM5441 may become a novel therapeutic agent for obesity and obesity-related metabolic disorders. Abbreviations ATGL, adipose triglyceride lipase; Cox, cytochrome c oxidase; FAS, fatty acid synthase; FFA, free fatty acid; GTT, glucose tolerance test; H&E, haematoxylin and eosin; HFD, high-fat diet; HSL, hormone-sensitive lipase; iNOS, inducible nitric oxide synthase; ITT, insulin tolerance test; KO, knockout; MCP-1, monocyte chemotactic protein-1; mtDNA, mitochon-drial DNA; ND, normal diet; PAI-1, plasminogen activator inhibitor-1; PGC1α, PPARγ coactivator-1α; Tfam, mitochondrial transcription factor A; TG, triglyceride; TM5275, 5-chloro-2-[({2-[4-(diphenylmethyl)piperazin-1-yl]-2-oxoethoxy}acetyl) amino]benzoate; TM5441, 5-chloro-2{[(2-{[3-(furan-3-yl)phenyl]amino}-2-oxoethoxy) acethyl]amino} benzoic acid; UCP, uncoupling protein; WAT, white adipose tissue

Peroxisomal Fitness: A Potential Protective Mechanism of Fenofibrate against High Fat Diet-Induced Non-Alcoholic Fatty Liver Disease in Mice

JIANG SONGLING,UDDIN MD JAMAL,Xiaoying Yu,Lingjuan Piao,Dorotea Debra,Oh Goo Taeg,Ha Hunjoo 대한당뇨병학회 2022 Diabetes and Metabolism Journal Vol.46 No.6

Background: Non-alcoholic fatty liver disease (NAFLD) has been increasing in association with the epidemic of obesity and diabetes. Peroxisomes are single membrane-enclosed organelles that play a role in the metabolism of lipid and reactive oxygen species. The present study examined the role of peroxisomes in high-fat diet (HFD)-induced NAFLD using fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) agonist.Methods: Eight-week-old male C57BL/6J mice were fed either a normal diet or HFD for 12 weeks, and fenofibrate (50 mg/kg/day) was orally administered along with the initiation of HFD.Results: HFD-induced liver injury as measured by increased alanine aminotransferase, inflammation, oxidative stress, and lipid accumulation was effectively prevented by fenofibrate. Fenofibrate significantly increased the expression of peroxisomal genes and proteins involved in peroxisomal biogenesis and function. HFD-induced attenuation of peroxisomal fatty acid oxidation was also significantly restored by fenofibrate, demonstrating the functional significance of peroxisomal fatty acid oxidation. In <i>Ppara</i> deficient mice, fenofibrate failed to maintain peroxisomal biogenesis and function in HFD-induced liver injury.Conclusion: The present data highlight the importance of PPARα-mediated peroxisomal fitness in the protective effect of fenofibrate against NAFLD.

8-Hydroxy-2-deoxyguanosine ameliorates high-fat diet-induced insulin resistance and adipocyte dysfunction in mice

Huh, Joo Young,Jung, Inji,Piao, Lingjuan,Ha, Hunjoo,Chung, Myung-Hee Academic Press 2017 Biochemical and biophysical research communication Vol. No.

<P><B>Abstract</B></P> <P>8-Hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, has been recently shown to exert anti-inflammatory effects through inhibition of Rac1. Inflammation in adipose tissue is a hallmark of obesity-induced insulin resistance, but the therapeutic potential of 8-OHdG in treatment of metabolic diseases has not been fully elucidated. The aim of this study was to examine the effect of exogenously administered 8-OHdG on adipose tissue and whole body metabolism. In cultured adipocytes, 8-OHdG inhibited adipogenesis and reversed TNFα-induced insulin resistance. In high-fat diet (HFD)-induced obese mice, 8-OHdG administration blunted the rise in body weight and fat mass. The decrease in adipose tissue mass by 8-OHdG was due to reduced adipocyte hypertrophy through induction of adipose triglyceride lipase and inhibition of fatty acid synthase expression. 8-OHdG also inhibited the infiltration of macrophages, resulting in amelioration of adipose tissue inflammation and adipokine dysregulation. Moreover, 8-OHdG administration ameliorated adipocyte as well as systemic insulin sensitivity. Both <I>in vivo</I> and <I>in vitro</I> results showed that 8-OHdG induces AMPK activation and reduces JNK activation in adipocytes. In conclusion, our results show that orally administered 8-OHdG protects against HFD-induced metabolic disorders by regulating adipocyte metabolism.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 8-OHdG administration protects mice from diet-induced obesity. </LI> <LI> 8-OHdG inhibits adipogenesis as well as adipocyte hypertrophy. </LI> <LI> 8-OHdG ameliorates adipocyte and whole body insulin sensitivity. </LI> <LI> 8-OHdG regulates adipocyte metabolism and exerts anti-inflammatory effects. </LI> </UL> </P>