Effects of TCDCA-FXR on obesity-induced endothelial dysfunction and hypertension III
To investigate the role of TCDCA-FXR in endothelial cells, we performed  CUT&TAG in HUVECs. Overall design: The transcription factor ATF4 has been reported to regulate the expression of the key enzymes involved in serine metabolism (PHGDH, PSAT1, and SHMT2) and one-carbon metabolism (MTHFD2, ALDH1L2). Knockdown of ATF4 in HUVECs treated with TCDCA led to a significant downregulation in the mRNA levels of PHGDH, PSAT1, and SHMT2. As a nuclear receptor and transcription factor, FXR can regulate gene expression upon TCDCA activation. To determine if FXR directly regulates ATF4 transcription, we performed cleavage under targets and tagmentation (CUT&TAG) assay using Flag antibody in HUVECs overexpressing Flag-tagged FXR. TCDCA treatment resulted in reduced nuclear enrichment of PHB1, while TUDCA maintained strong nuclear colocalization of FXR and PHB1. To further evaluated the role of PHB1, we performed CUT&TAG assay to evaluate the DNA-binding profiles of PHB1 in ECs