scholarly journals Trimethylamine-N-Oxide Pathway: A Potential Target for the Treatment of MAFLD

2021 ◽  
Vol 8 ◽  
Author(s):  
Xun Li ◽  
Jia Hong ◽  
Yao Wang ◽  
Maohua Pei ◽  
Luwen Wang ◽  
...  

Trimethylamine-N-oxide (TMAO) is a molecular metabolite derived from the gut flora, which has recently emerged as a candidate risk factor for metabolic dysfunction-associated fatty liver disease (MAFLD). TMAO is mainly derived from gut, where the gut microbiota converts TMA precursors into TMA, which is absorbed into the bloodstream through the intestinal mucosa, and then transformed into TMAO by hepatic flavin monooxygenases (FMOs) in the liver. High-nutrient diets rich in TMA precursors, such as red meat, eggs, and fish, are the main sources of TMAO. Excessively consuming such diets not only directly affects energy metabolism in liver, but also increases the concentration of TMAO in plasma, which promotes the development of MAFLD by affecting bile acid metabolism, unfolded protein response, and oxidative stress. In this review, we focused on the relationship between TMAO and MAFLD and summarized intervention strategies for reducing circulating TMAO concentration, aiming at providing new targets for the prevention and treatment of MAFLD.

2020 ◽  
Vol 13 (11) ◽  
pp. 355
Author(s):  
Paula Aranaz ◽  
David Navarro-Herrera ◽  
María Zabala ◽  
Ana Romo-Hualde ◽  
Miguel López-Yoldi ◽  
...  

Supplementation with bioactive compounds capable of regulating energy homeostasis is a promising strategy to manage obesity. Here, we have screened the ability of different phenolic compounds (myricetin, kaempferol, naringin, hesperidin, apigenin, luteolin, resveratrol, curcumin, and epicatechin) and phenolic acids (p-coumaric, ellagic, ferulic, gallic, and vanillic acids) regulating C. elegans fat accumulation. Resveratrol exhibited the strongest lipid-reducing activity, which was accompanied by the improvement of lifespan, oxidative stress, and aging, without affecting worm development. Whole-genome expression microarrays demonstrated that resveratrol affected fat mobilization, fatty acid metabolism, and unfolded protein response of the endoplasmic reticulum (UPRER), mimicking the response to calorie restriction. Apigenin induced the oxidative stress response and lipid mobilization, while vanillic acid affected the unfolded-protein response in ER. In summary, our data demonstrates that phenolic compounds exert a lipid-reducing activity in C. elegans through different biological processes and signaling pathways, including those related with lipid mobilization and fatty acid metabolism, oxidative stress, aging, and UPR-ER response. These findings open the door to the possibility of combining them in order to achieve complementary activity against obesity-related disorders.


2019 ◽  
Vol 20 (4) ◽  
pp. 857 ◽  
Author(s):  
Lorenza Sisinni ◽  
Michele Pietrafesa ◽  
Silvia Lepore ◽  
Francesca Maddalena ◽  
Valentina Condelli ◽  
...  

The unfolded protein response (UPR) is a stress response activated by the accumulation of unfolded or misfolded proteins in the lumen of the endoplasmic reticulum (ER) and its uncontrolled activation is mechanistically responsible for several human pathologies, including metabolic, neurodegenerative, and inflammatory diseases, and cancer. Indeed, ER stress and the downstream UPR activation lead to changes in the levels and activities of key regulators of cell survival and autophagy and this is physiologically finalized to restore metabolic homeostasis with the integration of pro-death or/and pro-survival signals. By contrast, the chronic activation of UPR in cancer cells is widely considered a mechanism of tumor progression. In this review, we focus on the relationship between ER stress, apoptosis, and autophagy in human breast cancer and the interplay between the activation of UPR and resistance to anticancer therapies with the aim to disclose novel therapeutic scenarios. The hypothesis that autophagy and UPR may provide novel molecular targets in human malignancies is discussed.


2020 ◽  
Author(s):  
Isabella R. Straub ◽  
Woranontee Weraarpachai ◽  
Eric A. Shoubridge

AbstractMutations in CHCHD10, coding for a mitochondrial intermembrane space protein, are a rare cause of autosomal dominant amyotrophic lateral sclerosis (ALS). Mutation-specific toxic gain of function or haploinsuffuciency models have been proposed to explain pathogenicity. To decipher the metabolic dysfunction associated with the haploinsufficient p.R15L variant we integrated transcriptomic, metabolomic and proteomic data sets in patient cells subjected to nutrient stress. Patient cells had a complex I deficiency resulting in an increased NADH/NAD+ ratio, downregulation of the TCA cycle, and a reorganization of one carbon metabolism. This led to phosphorylation of AMPK, activation of an endoplasmic reticulum and mitochondrial unfolded protein response (UPR), and the production of GDF15 and FGF21, which are markers of mitochondrial disease. The endoplasmic reticulum UPR was mediated through the IRE1/XBP1 pathway, and was accompanied by reduced eIF2alpha phosphorylation, dephosphorylation of both JNK isoforms, and up regulation of several dual specific phosphatases. This study demonstrates that loss of CHCHD10 function elicits a striking energy deficit that activates cellular stress pathways, which may underlie the selective vulnerability of motor neurons.


2019 ◽  
Vol 3 (24) ◽  
pp. 4155-4160 ◽  
Author(s):  
Silvia Masciarelli ◽  
Ernestina Capuano ◽  
Tiziana Ottone ◽  
Mariadomenica Divona ◽  
Serena Lavorgna ◽  
...  

Key Points RA synergizes with the N-glycosylation inhibitor tunicamycin and ATO to induce AML cell death via generation of ER and oxidative stress.


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