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Siragusa, M.

Publications and source records attributed to Siragusa, M..

2 recordsLinked to original sources
bioRxiv2023

Inhibition of proline-rich-tyrosine kinase 2 restores cardioprotection by remote ischemic preconditioning in type 2 diabetes mellitus

BackgroundEndothelial function and cardioprotection through remote ischemic preconditioning (rIPC) are severely impaired in type 2 diabetes mellitus (T2DM). Proline-rich tyrosine kinase 2 (Pyk2), a downstream target of the insulin receptor, reduces endothelial nitric oxide synthase (eNOS) activity. Therapeutic options to rescue cardioprotection in T2DM and improve outcomes after acute myocardial infarction (AMI) are lacking. We hypothesized that vascular endothelium contributes to rIPC, and that inhibition of Pyk2 restores cardioprotection in T2DM through modulation of eNOS, thus limiting infarct size. MethodsNew Zealand Obese (NZO) mice were used as a polygenic model of T2DM. Effects of Pyk2-inhibition on endothelial function, remote ischemic preconditioning (rIPC), and infarct size (IS) after ischemia/reperfusion (I/R) were compared in NZO, eNOS KO, and C57Bl/6 (Bl6) mice. Plasma derived from mice and individuals with or without T2DM at baseline and after rIPC was transferred to isolated hearts and aortic rings to assess the effects of Pyk2-inhibition on remote tissue protection. ResultsTransfer experiments with plasma drawn from non-diabetic humans and mice exposed to rIPC demonstrate that endothelium-dependent signals for remote tissue protection are conveyed by plasma. Key features reflecting the glucometabolic spectrum in T2DM were detected in NZO mice, including hyperinsulinemia, insulin resistance, obesity, and impaired glucose tolerance. Similar to T2DM patients, these mice also revealed endothelial dysfunction with decreased flow-mediated dilation (FMD), reduced circulating nitrite levels, elevated arterial blood pressure, and larger infarct size after I/R. Pyk2 increased the phosphorylation of eNOS on its inhibitory site (Tyr656). Cardioprotective effects by rIPC were lost in NZO mice. Inhibition of Pyk2 restored endothelial function and rescued endothelium-dependent cardioprotection after rIPC displayed by lower IS and improved LV function post I/R. ConclusionEndothelial function contributing to remote tissue protection is severely impaired in diabetes mellitus. Proline-rich tyrosine kinase 2 is a novel target to rescue cardioprotection through endothelium-dependent remote ischemic preconditioning, advocating its role in limiting infarct size in diabetes mellitus. Clinical perspective What is new?O_LIVascular endothelium contributes to remote tissue protection in ischemic preconditioning, which is severely impaired in diabetes C_LIO_LIProline-rich tyrosine kinase 2 reduces eNOS-activity, causes endothelial dysfunction, and impairs cardioprotection through ischemic preconditioning C_LIO_LIInhibition of proline-rich tyrosine kinase 2 restores eNOS activity, endothelial function, and cardioprotective effects of remote ischemic preconditioning limiting infarct size in an experimental model of diabetes. C_LI What are the clinical implications?O_LIProper endothelial function is cirtical to maintain cardiovascular health. Endothelial dysfunction contributes to impaired remote tissue protection in diabetes. C_LIO_LIThese data demonstrate for the first time that endothelium-dependent cardioprotection in myocardial ischemia/reperfusion through remote ischemic preconditioning can be restored in diabetes. C_LIO_LIProline-rich tyrosine kinase 2 is a novel target to restore endothelium-dependent remote cardioprotection to improve the outcome of diabetic patients with acute myocardial infarction. C_LI

physiology↗
bioRxiv2022

A novel role for cystathionine gamma lyase in the control of p53: impact on endothelial senescence and metabolic reprograming

AimsAdvanced age is unequivocally linked to the development of cardiovascular disease, however, the mechanisms leading to loss of endothelial cell regenerative capacity during aging remain poorly understood. Here we aimed to investigate novel mechanisms involved in endothelial cell senescence, that impact on endothelial cell transcription and the vascular repair response upon injury Methods and resultsRNA sequencing of a unique collection of native endothelial cells from young and aged individuals, showed that aging (20 vs. 80 years) is characterized by p53- mediated reprogramming to promote the expression of senescence-associate genes. Molecular analysis revelead that p53 accumulated and acetylated in the nucleus of aged human endothelial cells to suppress glycolysis. Metabolic flux analysis identified an associated reduction in glucose uptake and ATP availability that inhibited the assembly of the telomerase complex, which was essential for proliferation. Nuclear translocation of p53 in aged endothelial cells was attributed to the loss of the vasoprotective enzyme, cystathionine {gamma}-lyase (CSE), which physically anchored p53 in the cytosol. In mice, loss of endothelial cell CSE activated p53 and arrested vascular repair upon injury, while the AAV9 mediated re-expression of an active CSE mutant retained p53 in the cytosol, maintained endothelial glucose metabolism and proliferation, and prevented endothelial cell senescence. Adenoviral overexpression of CSE in human native aged endothelial cells maintained low p53 activity and re-activated telomerase to revert endothelial cell senescence. ConclusionOur data identified the interaction between CSE and p53 as a promising target to preserve vascular regeneration during aging. Key QuestionTo identify the mechanisms that regulate endothelial cell senescence under native conditions and their impact on vascular repair in aging. Key FindingLack of a physical interaction between CSE and p53 metabolically reprogrammes endothelial cells to reduce telomerase activity and halt endothelial cell regeneration. Take home messageInterventions to increase CSE expression represent a novel therapy against p53-induced endothelial cell cycle arrest and senescense Translational perspectiveEndothelial rejuvenation strategies could serve as promising therapies against age-related cardiovascular diseases. By investigating human native endothelial cells from young and aged individuals, we identified that the age-related nuclear accumulation of p53 reprograms endothelial cell metabolism, regulates telomerase activity and inhibits endothelial cell regeneration. Nuclear localization of p53 resulted from a loss of its interaction with the cysteine catabolizing enzyme cystathionine {gamma}-lyase in the cytoplasm. Enhancing the physical interaction of p53 with CSE by gene therapy could revert endothelial cell senescence and activate endothelial reparative responses.

cell biology↗