Abstract
BackgroundRecent studies indicate that umbilical cord stem cells are cytoprotective against several disorders. One critical limitation in using stem cells is reduction in their viability under stressful conditions, such as diabetes. However, the molecular intricacies responsible for diabetic conditions are not fully elucidated.MethodsEffects of HG on Wharton's jelly derived mesenchymal stem cells (WJMSCs) viability was evaluated by MTT assay and flow cytometry. The mechanism responsible for HG-induced PTEN degradation was assessed using loss and gain of function, immunofluorescence, co-immunoprecipitation, and western blot analysis. Co-culturing of CHIP-overexpressed WJMSCs with embryo derived cardiomyoblasts was performed to analyze their ameliorative effects. The therapeutic effects of CHIP expressing WJMSCs were further validated in Sprague Dawley male (eight weeks old) STZ-induced diabetic animals by echocardiography, immunohistochemistry, hematoxylin eosin, and masson’s trichrome and TUNEL staining. Multiple comparisons were accessed through one‐way ANOVA and p-Value of <0.05 was considered statistically significant. ResultsIn this study, we found that high glucose (HG) conditions induced loss of chaperone homeostasis, stabilized PTEN, triggered the downstream signaling cascade, and induced apoptosis and oxidative stress in Wharton's jelly derived mesenchymal stem cells (WJMSCs). Increased CHIP expression promoted PTEN degradation via the ubiquitin-proteasome system and shortened its half-life during HG stress. Docking studies confirmed the interaction of CHIP with PTEN and FOXO3a with the Bim promoter region. Further, it was found that the chaperone system is involved in CHIP-mediated PTEN proteasomal degradation. CHIP depletion stabilizes PTEN whereas PTEN inhibition showed an inverse effect. CHIP overactivation suppressed the binding of FOXO3a with bim. Co-culturing CHIP overexpressed WJMSCs suppressed HG-induced apoptosis and oxidative stress in cardiac cells. Finally, CHIP overexpression and PTEN inhibition minimized blood glucose levels, improved body and heart weight, and rescued hyperglycemia-induced cardiac injury in diabetic rats. ConclusionThe current study suggests that CHIP confers resistance to apoptosis and oxidative stress and modulates PTEN and the downstream signaling cascade by promoting PTEN proteasomal degradation, thereby potentially exerting therapeutic effects against diabetes-induced cardiomyopathies.
CHIP Reverses Hyperglycemia-associated PTEN Stability in Wharton's Jelly Derived Mesenchymal Stem Cells and Promotes Its Therapeutic Potential Against Diabetes-induced Cardiac Injury
