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Mechanical activation of Hippo/TGFb pathways lead human saphenous vein progenitors toward pro-fibrotic differentiation in aorto-coronary bypass failure. Cardiovasc Res 2022. [DOI: 10.1093/cvr/cvac066.157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ricerca Corrente
Introduction
We previously demonstrated that mechanical stress deriving from coronary flow/pressure patterns in the human saphenous vein (SV) conduits induce release of Thrombospondin-1 (TSP-1) by smooth muscle cells, and this activates adventitial progenitors (SVPs) pathologic activation.
Purpose
In this study, we show a cooperation of the TGF-β/TSP-1 signaling with the mechanically-activated Hippo transcriptional pathway in fibrotic SVPs commitment.
Methods
Human derived-SVPs were isolated using a MACS based protocol with a positive selection for CD34 and a negative depletion of CD31+ cells. We performed an RNA-seq analysis of SVPs subjected to 10% uniaxial deformation (n=5), followed by differential gene expression and pathway analyses. We validated results in vitro and in two animal models of vein arterialization.
Results
A response of SVPs to mechanical stimulation was assessed from variations in cell alignment, circularity and area. The susceptibility of SVPs to uniaxial strain was revealed by a trend of the cells to orientate in orthogonal direction to the strain field and changes in cell shape. Mechanically stimulated cells for 72 hrs showed a significant increase in their motility as verified by migration assays in the presence of medium supplemented with 10% serum. RNA-seq analysis of the total transcriptome expressed in these cells with/without mechanical stimulation was performed. The differentially expressed genes (DEGs) analysis highlighted a maximum variation of the transcriptome at 72hrs of mechanical stimulation vs. static controls with n=819 DEGs. A gene enrichment analysis revealed an involvement of the HIPPO/YAP/TEAD and of the TGF-β/SMAD transcriptional circuitries in mechanically-stimulated cells. In keeping, immunofluorescence and RT-qPCR showed an increase in YAP nuclear translocation and activity. We treated cells with a cytoskeleton inhibitor (Forskolin, FRSK) and a drug (Verteporfin, VTP) that prevents the interaction of the YAP/TAZ complex with TEADs. Both drugs inhibited expression of YAP-transcriptional targets and cellular motility in response to serum. We then treated cells with TGF-β1, TSP-1 alone or in combination. Under these conditions we observed an increased expression of YAP targets and CollA1, a higher amount of Collagen secretion in the supernatant and a higher association of YAP with pSMAD3. All these effects were blunted by VTP. YAP nuclear localization was finally validated in two models of vein arterialization in mice and pigs.
Conclusions
Our data suggest a convergent activation of Hippo/TGF-β pathways in the failure of the aorto-coronary bypass and highlight a future novel strategy to limit its progression in patients.
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Pharmacological blockade of histone methyltransferase SETD7 restores angiogenic response in experimental diabetes. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.3203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Background
Peripheral artery disease (PAD) is highly prevalent in patients with diabetes and associates with a high rate of limb amputation and poor prognosis. Surgical and catheter-based revascularization have failed to improve outcome in diabetic patients with PAD. Hence, a need exists to develop new treatment strategies able to promote blood vessel growth in the ischemic limb of diabetic patients. Mono-methylation of histone 3 at lysine 4 (H3K4me1) - a specific epigenetic signature induced by the methyltransferase SETD7 - favours a chromatin active and open state thus enabling the gene transcription.
Purpose
To investigate whether SETD7-dependent epigenetic changes modulate post-ischemic vascularization in experimental diabetes.
Methodology
Primary human aortic endothelial cells (HAECs) were exposed to normal glucose (NG, 5 mM) or high glucose (HG, 20 mM) concentrations for 48 hours. Unbiased gene expression profiling was performed by RNA sequencing (RNA-seq) followed by Ingenuity Pathway Analysis (IPA). In vitro angiogenic assays like migration assay & tube formation assay were performed. Pharmacological blockade of SETD7 was achieved by using the highly selective inhibitor called (R)-PFI-2. T1D mice (streptozotocin-induced diabetes) was orally treated with (R)-PFI-2 and with vehicle for 21 days and followed by induction of hindlimb ischemia. Blood flow recovery was analyzed at 30 minutes, 7 and 14 days by laser doppler imaging. Gastrocnemius muscle samples from patients with and without T2D were employed to translate our experimental findings.
Results
RNA-seq in HG-treated HAECs revealed a profound upregulation of the methyltransferase SETD7, an enzyme involved in mono-methylation of lysine 4 at histone 3 (H3K4me1). SETD7 upregulation in HG-treated HAECs was associated with an increase of H3K4-mono-methylation levels as well as with impaired endothelial cell migration and tube formation. Of interest, both gene silencing (SETD7-siRNA) and pharmacological blockade of SETD7 by (R)-PFI-2 rescued hyperglycemia-induced impairment of angiogenic properties in HAECs. RNA-seq in HG-treated HAECs with and without SETD7 depletion unveiled an array of differentially expressed genes, which were mainly involved in blood vessel growth and angiogenic response. Among dysregulated genes, Chromatin immunoprecipitation (ChIP) assays showed that SETD7 specifically mono-methylates H3K4m1 in proximity of Semaphorin-3G (SEMA3G) promoter, thus regulating its expression. Treatment of T1D mice with (R)-PFI-2 improved blood flow reperfusion at 14 days as compared to vehicle-treated animals. Finally, SETD7/SEMA3G axis was upregulated in muscle specimens from T2D patients.
Conclusion
Targeting SETD7 represents a novel epigenetic-based therapy to boost neovascularization in diabetic patients with PAD.
Funding Acknowledgement
Type of funding sources: Public Institution(s). Main funding source(s): University of Zurich
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