Project description:We applied the transcriptome profiling (RNA-seq) for high-throughput profiling of genes changes in VSMC dedifferentiation. Rat primary VSMCs were divided into 3 groups, control, PDGF-BB, PDGF-BB+PJ34,and mRNA sequence were performed. We found that PDGF-BB could upregualted the genes involved in cell proliferation and migration, and downregulated the VSMC contractile genes, all of which could be reversed by PARP inhibitor PJ34. Then we knockdowned the co-factor Myocardin in VSMCs, and found the above effects of PJ34 were nearly abolished.Our study first provided the transcription changes by RNA-seq in VSMC dedifferentiation, and demonstrated the key roles of PARP1 and the PARylation process in VSMC phenotypic switch.
Project description:Hutchinson Gilford Progeria Syndrome is a premature aging disease caused by LMNA gene mutation and the production of a truncated lamin A protein “progerin” that elicits cellular and organismal toxicity. Progerin accumulates in the vasculature, being especially toxic for vascular smooth muscle cells (VSMC). Patients' autopsies show that vessel stiffening, and aortic atherosclerosis is accompanied by VSMC depletion in the medial layer, altered extracellular matrix (ECM), and thickening of the adventitial layer. Mechanisms whereby progerin causes massive VSMC loss and vessel alterations remain poorly understood. Mature VSMC retain phenotypic plasticity and can switch to a synthetic/proliferative phenotype. Here we show that progerin expression in human and mouse VSMC causes a switch towards the synthetic/proliferative phenotype. This switch elicits some level of replication stress in normal cells, which is exacerbated in the presence of progerin, leading to telomere fragility, genomic instability, and ultimately VSMC death. Importantly, calcitriol prevents replication stress, telomere fragility, and genomic instability, reducing VSMC death. In addition, RNAseq analysis shows induction of a profibrotic and proinflammatory aging-associated secretory phenotype upon progerin expression in human primary VSMC. Our data suggest that phenotypic switch-induced replication stress might be an underlying cause of VSMC loss in progeria, which together with loss of contractile features and gain of profibrotic and proinflammatory signatures contribute to vascular stiffness in HGPS. Preventing the phenotypic switch-induced replication stress with compounds such as calcitriol might ameliorate CVD in HGPS patients
Project description:Myocardin (Myocd) plays an important role in the maintenance and homeostasis of the vasculature. The loss of Myocd results in vascular smooth muscle cell (VSMC) phenotypic transition and thoracic aortic aneurysms and dissections (TAADs) by downregulating VSMC contractile genes. VSMC phenotypic transition plays a key role in the formation of abdominal aortic aneurysms and dissections (AAADs). However, little is known about the role of Myocd in AAAD. The effect of Myocd on AAA formation was proven in an angiotensin II (Ang II)-induced AAD model. Myocd overexpression or knockdown was achieved by the injection of the corresponding adeno-associated virus serotype 9 (AAV9) through the tail vein. The knockdown of Myocd in C57BL/6J mice treated with angiotensin II promoted the formation of AAAD, as demonstrated by increases in the maximal aortic diameter, vascular inflammation and elastin degradation relative to the control group, while Myocd-overexpressing ApoE-/- mice infused with Ang II were less likely to develop AAAD. Mechanistically, Myocd deficiency significantly repressed VSMC marker gene expression. In addition, qPCR results showed that Myocd knockdown promoted the expression of lncRNAs, which showed increased levels in human AAD tissues. Our results indicated the pivotal role of Myocd in protecting against AAAD formation.
Project description:In this work, we investigated the pharmacological effects of ICS-II on VSMC phenotypic transition and reveal the underlying mechanisms through in vivo and in vitro experiments. Our results highlight the thera-peutic benefits of ICS-II targeting VSMC phenotypic transition and sup-port the potential of pharmacological strategies in CVD management.
Project description:Vascular calcification is a hallmark of atherosclerosis and end-stage renal disease (ESRD). However, the molecular mechanism of vascular calcification is poorly understood. Diabetes mellitus is increasingly recognized as the most important cause for atherosclerosis and ESRD. Emerging evidence supports the concept that vascular calcification resembles the process of osteogenesis, in which the vascular smooth muscle cells (VSMC) undergo osteochondrogenic differentiation. Recently, we have established an in vitro calcification system with primary mouse VSMC. With the use of osteogenic stimuli, we induced trans-differentiation of primary mouse VSMC into bone-like cells. Interestingly stroptozotocin (STZ), O-GlcNAcase inhibitor and a drug that has been used to induce diabetes in mice, was able to induce calcification of VSMC and the expression of the osteogenic transcription factor Runx2, suggesting glycosylation may be involved in regulation of Runx2. We have reported an essential role of Runx2 in oxidative stress-induce VSMC calcification and have recently generated a tissue specific mouse with Runx2 ablation in smooth muscle cells. Therefore, we will use STZ and other relevant reagents in the glucose synthesis/metabolism pathways as stimuli for VSMC calcification to characterize the glycogene profiles during VSMC calcification. Results from VSMC of Runx2 knockout mice will be compared with those from control mice to determine the regulation of calcification-associated glycogenes by Runx2 in response to STZ. These studies will provide foundation for further mechanistic studies and may lead to identification of novel strategies and targets for diabetes-induced vascular calcification. To examine vascular smooth muscle cells (VSMC) under two conditions: 1) wild-type VSMC differentiated into bone-like cells with osteogenic media, 2) wild-type VSMC treated with STZ and osteogenic media