scholarly journals ER Stress Inhibits Liver Fatty Acid Oxidation while Unmitigated Stress Leads to Anorexia-Induced Lipolysis and Both Liver and Kidney Steatosis

Cell Reports ◽  
2017 ◽  
Vol 19 (9) ◽  
pp. 1794-1806 ◽  
Author(s):  
Diane DeZwaan-McCabe ◽  
Ryan D. Sheldon ◽  
Michelle C. Gorecki ◽  
Deng-Fu Guo ◽  
Erica R. Gansemer ◽  
...  
Lipids ◽  
1999 ◽  
Vol 34 (S1) ◽  
pp. S95-S95
Author(s):  
S. Sidossis ◽  
B. Mittendorfer ◽  
E. Walser ◽  
D. Chinkes ◽  
R. Wolfe

2017 ◽  
Vol 59 (2) ◽  
pp. 330-338 ◽  
Author(s):  
Xinchen Qiu ◽  
Jian Li ◽  
Sihan Lv ◽  
Jiamin Yu ◽  
Junkun Jiang ◽  
...  

1990 ◽  
Vol 68 (1) ◽  
pp. 260-265 ◽  
Author(s):  
Joan Letto ◽  
John T. Brosnan ◽  
Margaret E. Brosnan

The interactions between fatty acid oxidation and the oxidation of the 2-oxo acids of the branched chain amino acids were studied in the isolated Langendorff-perfused heart. 2-Oxoisocaproate inhibited the oxidation of oleate, but 2-oxoisovalerate and 2-oxo-3-methylvalerate did not. This difference was not attributable to the magnitude of the flux through the branched chain 2-oxo acid dehydrogenase, which was slightly higher with 2-oxoisovalerate than with 2-oxoisocaproate. Oxidation of 2-oxoisocaproate in the perfused heart was virtually complete, since more than 80% of the isovaleryl-CoA formed from 2-oxo[1-14C]isocaproate was further metabolized to CO2, as determined by comparing 14CO2 production from 2-oxo[14C(U)]isocaproate with that from the 1-14C-labelled compound. Only twice as much 14CO2 was produced from 2-oxo[14C(U)]isovalerate as from the 1-14C-labelled compound, indicating incomplete oxidation. This was confirmed by the accumulation in the perfusion medium of substantial quantities of labelled 3-hydroxyisobutyrate (an intermediate in the pathway of valine catabolism), when hearts were perfused with 2-oxo[14C(U)]isovalerate. The failure of 2-oxoisovalerate to inhibit fatty acid oxidation, then, can be attributed to the fact that its partial metabolism in the heart produces little ATP. We have previously shown that 3-hydroxyisobutyrate is a good gluconeogenic substrate in liver and kidney, and postulate that 3-hydroxyisobutyrate serves as an interorgan metabolite such that valine can serve as a glucogenic amino acid, even when its catabolism proceeds beyond the irreversible 2-oxo acid dehydrogenase in muscle.Key words: branched chain amino acids, branched chain 2-oxoacids, perfused heart, fatty acid metabolism, 3 -hydroxyisobutyrate.


2019 ◽  
Vol 20 (19) ◽  
pp. 4801 ◽  
Author(s):  
Ji-Hyun Kim ◽  
Hyun A Sim ◽  
Dae Young Jung ◽  
Eun Yeong Lim ◽  
Yun Tai Kim ◽  
...  

Poria cocos Wolf (PCW) is an edible, pharmaceutical mushroom with remarkable biological properties including anti-tumor, anti-inflammation, anti-oxidation, anti-ageing, and anti-diabetic effects. In the current study, we investigated the effects of PCW extract on hepatic steatosis under in vitro and in vivo conditions, and elucidated the underlying mechanisms. In this study, a mixture of HepG2 cells treated with free fatty acid (FFA)—palmitic and oleic acid—and high-fat diet (HFD)-fed obese mice were used; in this background, the triglyceride (TG) levels in HepG2 cells and mice liver were measured, and the expression levels of genes associated with lipogenesis, fatty acid oxidation, endoplasmic reticulum (ER) stress, and autophagy were determined. Treatment of HepG2 cells with FFA enhanced intracellular TG levels in HepG2 cells, but co-treatment with PCW significantly attenuated the TG levels. Notably, PCW significantly enhanced the phosphorylation of AMP-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), and sterol regulatory element-binding protein-1c (SREBP-1c) in FFA-treated HepG2 cells. PCW downregulated the expression of lipogenesis-related genes, but upregulated the expression of genes associated with fatty acid oxidation. Further, PCW inhibited FFA-induced expression of ER stress markers and induced autophagy proteins. However, inhibition of AMPK significantly attenuated the beneficial effects of PCW in HepG2 cells. Moreover, PCW efficiently decreased HFD-induced hepatic TG accumulation in vivo and increased the phosphorylation of hepatic AMPK. Three compounds present in PCW including poricoic acid, pachymic acid, and ergosterol, significantly decreased FFA-induced increase in intracellular TG levels, consistent with increased AMPK phosphorylation, suggesting that poricoic acid, pachymic acid, and ergosterol are responsible for PCW-mediated amelioration of hepatic steatosis. Taken together, these results demonstrated that PCW ameliorates hepatic steatosis through the regulation of lipid metabolism, inhibition of ER stress, and activation of autophagy in an AMPK-dependent manner. This suggested that PCW can be potentially used for the treatment of hepatic steatosis.


2014 ◽  
Vol 306 (4) ◽  
pp. F401-F409 ◽  
Author(s):  
Kapil Kampe ◽  
Jonas Sieber ◽  
Jana Marina Orellana ◽  
Peter Mundel ◽  
Andreas Werner Jehle

Type 2 diabetes is characterized by dyslipidemia with elevated free fatty acids (FFAs). Loss of podocytes is a hallmark of diabetic nephropathy, and podocytes are susceptible to saturated FFAs, which induce endoplasmic reticulum (ER) stress and podocyte death. Genome-wide association studies indicate that expression of acetyl-CoA carboxylase (ACC) 2, a key enzyme of fatty acid oxidation (FAO), is associated with proteinuria in type 2 diabetes. Here, we show that stimulation of FAO by aminoimidazole-4-carboxamide-1β-d-ribofuranoside (AICAR) or by adiponectin, activators of the low-energy sensor AMP-activated protein kinase (AMPK), protects from palmitic acid-induced podocyte death. Conversely, inhibition of carnitine palmitoyltransferase (CPT-1), the rate-limiting enzyme of FAO and downstream target of AMPK, augments palmitic acid toxicity and impedes the protective AICAR effect. Etomoxir blocked the AICAR-induced FAO measured with tritium-labeled palmitic acid. The beneficial effect of AICAR was associated with a reduction of ER stress, and it was markedly reduced in ACC-1/-2 double-silenced podocytes. In conclusion, the stimulation of FAO by modulating the AMPK-ACC-CPT-1 pathway may be part of a protective mechanism against saturated FFAs that drive podocyte death. Further studies are needed to investigate the potentially novel therapeutic implications of these findings.


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