Diyun Xu’s research while affiliated with Wenzhou Medical University and other places

Vascular injury is a serious complication associated with hypertension, for which effective treatments are currently lacking. Oxidative stress serves as the primary pathophysiological mechanism underlying hypertension-induced vascular injury. Carnosol, an extract derived from rosemary, has garnered increasing interest because of its well-established antioxidant properties. However, its potential therapeutic effect on vascular injury remains unclear. This study investigated the therapeutic potential of carnosol in angiotensin II-stimulated vascular injury and elucidated its underlying mechanisms of action. C57BL/6J mice were subjected to vascular injury through the subcutaneous implantation of a micropump filled with Ang II, followed by the intragastric administration of carnosol for four weeks. Carnosol ameliorated Ang II-stimulated vascular dysfunction and remodeling in a dose-dependent manner. Mechanistically, carnosol exerted an inhibitory effect on oxidative stress in the vascular tissue and HUVECs by regulating the PI3K/AKT pathway. Furthermore, we revealed that FAK, which received the highest target score in the molecular docking analysis, could directly bind to carnosol in both cellular models and human aortic tissues. Additionally, carnosol inhibited the phosphorylation of FAK, thereby reducing oxidative stress levels in HUVECs. Notably, when PND-1186 was administered to inhibit the phosphorylation of FAK, carnosol was no longer able to modulate the PI3K/AKT signaling pathway. In conclusion, we showed that carnosol can inhibit the PI3K/AKT signaling pathway by binding to the FAK protein and reducing its phosphorylation, thereby improving Ang II-stimulated vascular injury.

Background Myocardial ischemia/reperfusion injury (MI/RI) restricts the effect of myocardial reperfusion therapy and lacks effective prevention and treatment methods. Deubiquitinating enzymes (DUBs), especially members of the ubiquitin‐specific protease (USP) family of DUBs, are key proteins in the ubiquitination modification process and play a vital role in MI/RI. Therefore, we aimed to investigate the role of USP25, as a member of the USP family, in MI/RI and its molecular mechanism. Methods Transcriptome sequencing was applied to evaluate the differential expression of USP families during hypoxia/reoxygenation (H/R) and validated in human and mouse heart samples and cardiomyocytes by performing quantitative polymerase chain reaction. Wild‐type or USP25−/− mice were used to develop the MI/RI model. Co‐immunoprecipitation (Co‐IP) combined with liquid chromatography–tandem mass spectrometry analysis was used to screen the potential substrate protein of USP25 in H/R‐induced cardiomyocyte injury. TUNEL and Hoechst/propidium iodide staining and western blot were used to detect the level of pyroptosis. In addition, cardiomyocyte‐specific USP25 overexpression in NLRP3−/− mice with AAV9 vectors was used to validate the biological function of USP25 and NLRP3 interaction. Results We found that the expression level of USP25 was significantly decreased in I/R‐induced mouse heart tissues and primary cardiomyocytes in a time‐dependent manner. USP25 deficiency exacerbated MI/RI and aggravated I/R‐induced cardiac remodelling in mice. Mechanistically, USP25 directly binds to NLRP3 protein and K63‐linkedly deubiquitinates NLRP3 at residue K243 via its active site C178, thus hindering NLRP3–ASC interaction and ASC oligomerization to inhibit NLRP3 activation and pyroptosis in cardiomyocytes. We further showed that the overexpression of USP25 in cardiomyocytes ameliorated MI/RI in mice, whereas this protective effect disappeared when NLRP3 is knocked out. Conclusions Our study demonstrated that USP25 ameliorates MI/RI by regulating NLRP3 activation and its mediated pyroptosis. This finding extends the protective role of USP25 in cardiovascular disease and provides an experimental basis for future USP25‐based drug development for the treatment of MI/RI. Key points The deubiquitinating enzyme USP25 was down‐regulated both in myocardial ischemia/reperfusion injury (MI/RI) myocardium tissues. The deficiency of USP25 worsened exacerbated MI/RI in mice, whereas the overexpression of USP25 in cardiomyocytes mitigated this pathological phenotype. USP25 directly interacts with the NLRP3 protein and deubiquitinates it via K63 linkage at residue K243 through its active site C178, thus affecting NLRP3‐ASC interaction and ASC oligomerization to inhibit NLRP3 activation and pyroptosis in cardiomyocytes.

Deubiquitinating enzymes play a vital role in cardiovascular diseases. This study found that cardiomyocyte ubiquitin-specific protease 25 (USP25) expression was downregulated both in myocardial tissue of obesity cardiomyopathy and palmitic acid–stimulated cardiomyocytes. USP25 deficiency exacerbated high-fat diet–induced ventricular remodeling in mice, whereas overexpression of USP25 in cardiomyocytes reversed this pathological phenotype. Mechanistically, USP25 directly binds to TAK1 and P62, and the 178-cysteine of USP25 removes the K63 ubiquitin chain from P62, which promotes the degradation of TAK1 through the autophagy-lysosome pathway, thereby ameliorating obesity-induced ventricular remodeling by reducing inflammation through the TAK1-MAPK pathway. This finding identifies USP25 as a potential therapeutic target for obesity cardiomyopathy.

Recent studies have shown the crucial role of podocyte injury in the development of diabetic kidney disease (DKD). Deubiquitinating modification of proteins is widely involved in the occurrence and development of diseases. Here, we explore the role and regulating mechanism of a deubiquitinating enzyme, OTUD5, in podocyte injury and DKD. RNA-seq analysis indicates a significantly decreased expression of OTUD5 in HG/PA-stimulated podocytes. Podocyte-specific Otud5 knockout exacerbates podocyte injury and DKD in both type 1 and type 2 diabetic mice. Furthermore, AVV9-mediated OTUD5 overexpression in podocytes shows a therapeutic effect against DKD. Mass spectrometry and co-immunoprecipitation experiments reveal an inflammation-regulating protein, TAK1, as the substrate of OTUD5 in podocytes. Mechanistically, OTUD5 deubiquitinates K63-linked TAK1 at the K158 site through its active site C224, which subsequently prevents the phosphorylation of TAK1 and reduces downstream inflammatory responses in podocytes. Our findings show an OTUD5-TAK1 axis in podocyte inflammation and injury and highlight the potential of OTUD5 as a promising therapeutic target for DKD.