PERK specific inhibitor AMG-44 protects against Trimethylamine N-oxide (TMAO)-induced Endoplasmic Reticular Stress and Endothelial Dysfunction

The gut microbiota is known to release metabolites detrimental to the endothelial cell lining of the vascular wall leading to endothelial dysfunction. We have earlier reported that Trimethylamine N-oxide (TMAO), an intestinal microbe derived metabolite, caused endothelial dysfunction. In the present study we hypothesized that protein kinase R-like endoplasmic reticulum kinase (PERK)/eIF2α/ATF4 signaling is involved in TMAO-induced endoplasmic reticular (ER) stress and that treatment with PERK inhibitor AMG-44 protects against TMAO-induced ER stress. The endothelial cells were treated with a range of increasing doses of TMAO (0-300 μM) to induce ER stress. PERK inhibitor AMG-44 (20 – 200nM) was used to treat the TMAO treated and control cells. TAMO showed a dose-dependent upregulation of ER stress marker proteins involved in the PERK/eIF2α/ATF4 ER-stress signaling pathway. Western blot analysis showed significant increase in p-PERK/PERK, p-eIF2α/eIF2α, and IRE1α, AFT-4 protein expression which was further confirmed by immunofluorescent analysis in endothelial cells. Treatment with AMG-44 significantly attenuated the PERK/eIF2α/ATF4 axis also protected against increased endothelial cell permeability induced by TMAO (n=6/group; p<0.05). Our results demonstrate that TMAO-induced endothelial dysfunction via the ER stress-mediated PERK- eIF2 α -ATF4 signaling pathway and that treatment with PERK specific inhibitor AMG-44 could be a novel therapeutic strategy in protection against TMAO-induced ER stress and endothelial dysfunction. NIH R01HL148711 to Dr. Sai Sudha Koka. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.