scholarly journals The methyltransferase METTL3 negatively regulates nonalcoholic steatohepatitis (NASH) progression

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xinzhi Li ◽  
Bingchuan Yuan ◽  
Min Lu ◽  
Yuqin Wang ◽  
Na Ding ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Nonalcoholic Steatohepatitis ◽  
Promoter Region ◽  
Molecular Mechanisms ◽  
Fatty Acid Uptake ◽  
Chromatin Accessibility ◽  
Negative Regulator ◽  
Acid Uptake ◽  
Nonalcoholic Fatty Liver ◽  
Specific Deletion

AbstractNonalcoholic steatohepatitis (NASH) is a key step in the progression of nonalcoholic fatty liver (NAFL) to cirrhosis. However, the molecular mechanisms of the NAFL-to-NASH transition are largely unknown. Here, we identify methyltransferase like 3 (METTL3) as a key negative regulator of NASH pathogenesis. Hepatocyte-specific deletion of Mettl3 drives NAFL-to-NASH progression by increasing CD36-mediated hepatic free fatty acid uptake and CCL2-induced inflammation, which is due to increased chromatin accessibility in the promoter region of Cd36 and Ccl2. Antibody blockade of CD36 and CCL2 ameliorates NASH progression in hepatic Mettl3 knockout mice. Hepatic overexpression of Mettl3 protects against NASH progression by inhibiting the expression of CD36 and CCL2. Mechanistically, METTL3 directly binds to the promoters of the Cd36 and Ccl2 genes and recruits HDAC1/2 to induce deacetylation of H3K9 and H3K27 in  their promoters, thus suppressing Cd36 and Ccl2 transcription. Furthermore, METTL3 is translocated from the nucleus to the cytosol in NASH, which is associated with CDK9-mediated phosphorylation of METTL3. Our data reveal a mechanism by which METTL3 negatively regulates hepatic Cd36 and Ccl2 gene transcription via a histone modification pathway for protection against NASH progression.

scholarly journals Loss of Hepatocyte-Specific PPARγ Expression Ameliorates Early Events of Steatohepatitis in Mice Fed the Methionine and Choline-Deficient Diet

PPAR Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Jose Cordoba-Chacon
Keyword(s):  
Fatty Acid ◽  
Molecular Mechanisms ◽  
Fatty Acid Uptake ◽  
Peroxisome Proliferator ◽  
Acid Uptake ◽  
Deficient Diet ◽  
Peroxisome Proliferator Activated Receptor ◽  
Nonalcoholic Fatty Liver ◽  
Cd36 Expression ◽  
Pparγ Expression

The prevalence of nonalcoholic fatty liver disease (NAFLD) is increasing worldwide. To date, there is not a specific and approved treatment for NAFLD yet, and therefore, it is important to understand the molecular mechanisms that lead to the progression of NAFLD. Methionine- and choline-deficient (MCD) diets are used to reproduce some features of NAFLD in mice. MCD diets increase the expression of hepatic peroxisome proliferator-activated receptor gamma (PPARγ, Pparg) and the fatty acid translocase (CD36, Cd36) which could increase hepatic fatty acid uptake and promote the progression of NAFLD in mice and humans. In this study, we assessed the contribution of hepatocyte-specific PPARγ and CD36 expression to the development of early events induced by the MCD diet. Specifically, mice with adult-onset, hepatocyte-specific PPARγ knockout with and without hepatocyte CD36 overexpression were fed a MCD diet for three weeks. Hepatocyte PPARγ and/or CD36 expression did not contribute to the development of steatosis induced by the MCD diet. However, the expression of inflammatory and fibrogenic genes seems to be dependent on the expression of hepatocyte PPARγ and CD36. The expression of PPARγ and CD36 in hepatocytes may be relevant in the regulation of some features of NAFLD and steatohepatitis.

Lipid Metabolism and Liver Inflammation. I. Hepatic fatty acid uptake: possible role in steatosis

2006 ◽  
Vol 290 (2) ◽  
pp. G194-G198 ◽  
Author(s):  
Michael W. Bradbury
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Fatty Liver ◽  
Type Ii Diabetes ◽  
Fatty Acid Uptake ◽  
Health Concern ◽  
Acid Uptake ◽  
Public Health Concern ◽  
Nonalcoholic Fatty Liver

Hepatic steatosis is a growing public health concern. Nonalcoholic fatty liver is increasingly common in Western societies and may lead to steatohepatitis, fibrosis, and cirrhosis, possibly triggered by lipid peroxidation. The relation of fatty liver to obesity, type II diabetes, and/or metabolic syndrome is significant. One aspect these related disorders share is increased serum-free fatty acids, which may be taken up by hepatocytes. Uptake of fatty acids in excess of metabolic requirements will lead to storage as triglycerides, resulting in steatosis and providing substrate for lipid peroxidation. Fatty acid uptake may be crucial to understanding steatosis.

Unaltered Fatty Acid Uptake, Utilization, and Mitochondrial Respiration in Right Atrial Appendage of Type 2 Diabetic Human Heart

Diabetes ◽  
2018 ◽  
Vol 67 (Supplement 1) ◽  
pp. 335-OR
Author(s):  
NANDINI RJ ◽  
SR RAJI ◽  
VIVEK V. PILLAI ◽  
JAYAKUMAR K. ◽  
SRINIVAS GOPALA
Keyword(s):  
Fatty Acid ◽  
Mitochondrial Respiration ◽  
Human Heart ◽  
Fatty Acid Uptake ◽  
Atrial Appendage ◽  
Right Atrial ◽  
Acid Uptake ◽  
Right Atrial Appendage ◽  
Type 2 Diabetic

scholarly journals Kdm2a deficiency in macrophages enhances thermogenesis to protect mice against HFD-induced obesity by enhancing H3K36me2 at the Pparg locus

2021 ◽  
Author(s):  
Longmin Chen ◽  
Jing Zhang ◽  
Yuan Zou ◽  
Faxi Wang ◽  
Jingyi Li ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
High Fat Diet ◽  
Macrophage Polarization ◽  
Fatty Acid Uptake ◽  
Chromatin Accessibility ◽  
Acid Uptake ◽  
High Fat ◽  
M2 Polarization ◽  
Adipose Tissue Macrophages ◽  
Cold Challenge

AbstractKdm2a catalyzes H3K36me2 demethylation to play an intriguing epigenetic regulatory role in cell proliferation, differentiation, and apoptosis. Herein we found that myeloid-specific knockout of Kdm2a (LysM-Cre-Kdm2af/f, Kdm2a−/−) promoted macrophage M2 program by reprograming metabolic homeostasis through enhancing fatty acid uptake and lipolysis. Kdm2a−/− increased H3K36me2 levels at the Pparg locus along with augmented chromatin accessibility and Stat6 recruitment, which rendered macrophages with preferential M2 polarization. Therefore, the Kdm2a−/− mice were highly protected from high-fat diet (HFD)-induced obesity, insulin resistance, and hepatic steatosis, and featured by the reduced accumulation of adipose tissue macrophages and repressed chronic inflammation following HFD challenge. Particularly, Kdm2a−/− macrophages provided a microenvironment in favor of thermogenesis. Upon HFD or cold challenge, the Kdm2a−/− mice manifested higher capacity for inducing adipose browning and beiging to promote energy expenditure. Collectively, our findings demonstrate the importance of Kdm2a-mediated H3K36 demethylation in orchestrating macrophage polarization, providing novel insight that targeting Kdm2a in macrophages could be a viable therapeutic approach against obesity and insulin resistance.

scholarly journals Lipid Accumulation and Chronic Kidney Disease

Nutrients ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 722 ◽  
Author(s):  
Zhibo Gai ◽  
Tianqi Wang ◽  
Michele Visentin ◽  
Gerd Kullak-Ublick ◽  
Xianjun Fu ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Kidney Disease ◽  
Lipid Accumulation ◽  
Scavenger Receptor ◽  
Fatty Acid Uptake ◽  
Lipid Lowering ◽  
Fatty Acid Transport ◽  
Acid Uptake

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Effect of insulin on free fatty acid uptake by hepatocytes in the duck

1984 ◽  
Vol 102 (3) ◽  
pp. 381-386 ◽  
Author(s):  
R. Gross ◽  
P. Mialhe
Keyword(s):  
Fatty Acids ◽  
Growth Hormone ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Glucose Metabolism ◽  
Free Fatty Acids ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Low Doses ◽  
Higher Doses

ABSTRACT To elucidate the hypolipacidaemic effect of insulin in ducks, its action on the uptake of free fatty acids (FFA) by duck hepatocytes was determined. At low doses (10 mu./l) insulin stimulated FFA uptake. This effect was not observed with higher doses of insulin (20, 30 and 50 mu./l). Growth hormone at physiological concentrations and corticosterone (14·4 nmol/l) decreased basal activity, probably by reducing glucose metabolism and consequently α-glycerophosphate (α-GP) supply. Insulin was able to reverse the inhibition induced by GH and corticosterone on both FFA uptake and α-GP production. These results therefore suggest that the hypolipacidaemic effect of insulin may be partly mediated by its action on hepatic FFA uptake. J. Endocr. (1984) 102, 381–386

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