Myeloid-derived growth factor suppresses VSMC dedifferentiation and attenuates postinjury neointimal formation in rats by activating S1PR2 and its downstream signaling.

Restenosis after angioplasty is caused usually by neointima formation characterized by aberrant vascular smooth muscle cell (VSMC) dedifferentiation. Myeloid-derived growth factor (MYDGF), secreted from bone marrow-derived monocytes and macrophages, has been found to have cardioprotective effects. In this study we investigated the effect of MYDGF to postinjury neointimal formation and the underlying mechanisms. Rat carotid arteries balloon-injured model was established. We found that plasma MYDGF content and the level of MYDGF in injured arteries were significantly decreased after balloon injury. Local application of exogenous MYDGF (50 µg/mL) around the injured vessel during balloon injury markedly ameliorated the development of neointimal formation evidenced by relieving the narrow endovascular diameter, improving hemodynamics, and reducing collagen deposition. In addition, local application of MYDGF inhibited VSMC dedifferentiation, which was proved by reversing the elevated levels of osteopontin (OPN) protein and decreased levels of α-smooth muscle actin (α-SMA) in the left carotid arteries. We showed that PDGF-BB (30 ng/mL) stimulated VSMC proliferation, migration and dedifferentiation in vitro; pretreatment with MYDGF (50-200 ng/mL) concentration-dependently eliminated PDGF-BB-induced cell proliferation, migration and dedifferentiation. Molecular docking revealed that MYDGF had the potential to bind with sphingosine-1-phosphate receptor 2 (S1PR2), which was confirmed by SPR assay and Co-IP analysis. Pretreatment with CCG-1423 (Rho signaling inhibitor), JTE-013 (S1PR2 antagonist) or Ripasudil (ROCK inhibitor) circumvented the inhibitory effects of MYDGF on VSMC phenotypic switching through inhibiting S1PR2 or its downstream RhoA-actin monomers (G-actin) /actin filaments (F-actin)-MRTF-A signaling. In summary, this study proves that MYDGF relieves neointimal formation of carotid arteries in response to balloon injury in rats, and suppresses VSMC dedifferentiation induced by PDGF-BB via S1PR2-RhoA-G/F-actin-MRTF-A signaling pathway. In addition, our results provide evidence for cross talk between bone marrow and vasculature.

Differentially Expressed Circular Non-coding RNAs in Atherosclerotic Aortic Vessels and Their Potential Functions in Endothelial Injury.

Background: Circular non-coding RNA (circRNA) has a variety of biological functions. However, the expression profile and potential effects of circRNA on atherosclerosis (AS) and vascular endothelial injury have not been fully elucidated. This study aims to identify the differentially expressed circRNAs in atherosclerotic aortic vessels and predict their potential functions in endothelial injury. Method: ApoE-/- mice were fed with high-fat diet for 12 weeks to induce AS. Atherosclerotic plaques were evaluated by H&E and Masson staining and immunohistochemistry; differentially expressed circRNAs were detected by Arraystar Circular RNA Microarray and verified by RT-PCR; the potential target mircoRNAs of circRNAs were predicted by miRanda, Tarbase, Targetscan and their expression changes were verified by RT-PCR; the potential target genes of mircoRNAs were predicted by Targetscan and verified by Western blot; the signaling pathways that they might annotate or regulate and their potential functions in vascular endothelial injury were predicted by gene enrichment analysis. Results: Fifty two circRNAs were up-regulated more than twice and 47 circRNAs were down-regulated more than 1.5 times in AS aortic vessels. Mmmu_circRNA_36781 and 37699 were up-regulated both in AS aortic vessels and H2O2-treated mouse aortic endothelial cells (MAECs). The expression of miR-30d-3p and miR-140-3p, the target microRNA of circRNA_37699 and circRNA_36781, were downregulated both in AS vessels and H2O2-treated MAECs. On the contrary, MKK6 and TP53RK, the potential target gene of miR-140-3p and miR-30d-3p, were upregulated both in AS aortic roots and H2O2-treated MAECs. Besides, gene enrichment analysis showed that MAPK and PI3K-AKT signaling pathway were the most potential signaling pathways regulated by the differentially expressed circRNAs in atherosclerosis. Conclusions: Mmu_circRNA_36781 (circRNA ABCA1) and 37699 (circRNA KHDRBS1) were significantly up-regulated in AS aortic vessels and H2O2-treated MAECs. They have potential regulatory effects on atherosclerosis and vascular endothelial injury by targeting miR-30d-3p-TP53RK and miR-140-3p-MKK6 axis and their downstream signaling pathways.

Adoptive transfer of syngeneic bone marrow-derived cells in mice with obesity-induced diabetes: selenoorganic antioxidant ebselen restores stem cell competence.

There are conflicting data regarding the effects of transplantation of bone marrow-derived cells (BMDCs) on the severity of diabetes. We therefore inquired whether the competence of BMDCs is preserved on adoptive transfer into diabetic (db/db) mice and how the adoptive transfer of BMDCs affects vascular and metabolic abnormalities in these mice. Recipient db/db mice received infusions of BMDCs prepared from either db/db or non-diabetic heterozygout mice (db/m) mice and effects on endothelium-dependent relaxation, insulin sensitivity, and renal function were evaluated. Recipients of BMDCs from db/m, but not db/db donors showed better glucose control, exhibited striking improvement in endothelium-dependent relaxation in response to acetylcholine, and had partially restored renal function. Improved glucose control was due to enhanced insulin sensitivity, most likely secondary to improved vascular function. Enhanced apoptosis of endothelial progenitor cells under oxidative stress, as well as decreased endothelial progenitor cell numbers were responsible for the apparent functional incompetence of BMDCs from db/db donors. Treatment of db/db mice with Ebselen restored the resistance of both BMDCs and endothelial progenitor cells to oxidative stress, improved acetylcholine-induced vasorelaxation, and reduced proteinuria in db/db recipients of BMDC transplantation. In conclusion, infusion of BMDCs obtained from db/m donors to db/db recipient mice benefited macrovascular function, insulin sensitivity, and nephropathy. BMDCs obtained from db/db mice were functionally incompetent secondary to the increased proportion of apoptotic cells on oxidative stress challenge; their competence was restored by Ebselen therapy.

Kidney-derived mesenchymal stem cells contribute to vasculogenesis, angiogenesis and endothelial repair.

We isolated a clonal cell line (4E) from kidneys of mice expressing green fluorescent protein controlled by the endothelial-specific Tie2 promoter. When grown in a three-dimensional matrigel matrix they formed a fluorescent capillary network. In vivo angiogenesis assays using growth factor-depleted matrigel implanted plugs promoted a moderate angiogenesis of host endothelial cells. Using vascular endothelial growth factor (VEGF)-A and fibroblast growth factor-2 in the plugs containing 4E-cells resulted in a robust vasculogenesis. Transplantation of 4E cells into mice with acute renal ischemia showed selective engraftment in the ischemic kidney which promoted tubular regeneration by increasing epithelial proliferation and inhibiting apoptosis. This resulted in an accelerated functional recovery 3 days after ischemia. These mice showed a 5-fold increase in tissue VEGF expression compared to controls, but no difference in plasma VEGF level corresponding with better preservation of peritubular capillaries, perhaps due to a local paracrine effect following systemic 4E infusion. One month after ischemia, 9% of engrafted 4E cells expressed green fluorescent protein in the peritubular region while half of them expressed alpha-smooth muscle actin. Our study shows that kidney mesenchymal stem cells are capable of differentiation toward endothelial and smooth muscle cell lineages in vitro and in vivo, support new blood vessel formation in favorable conditions and promote functional recovery of an ischemic kidney.

Resveratrol, a natural ingredient of grape skin: antiarrhythmic efficacy and ionic mechanisms.

Resveratrol has been demonstrated to produce a variety of biological actions. Accumulating line of evidence supported the view that resveratrol may exert protective effect on the cardiovascular system. The aim of the study was to assess the antiarrhythmic profile as well as electrophysiological properties of resveratrol. We observe the antiarrhythmic effect of resveratrol on aconitine induced rat arrhythmia, ouabain induced guinea pig arrhythmia, and coronary ligation induced rat arrhythmia animal models. Resveratrol significantly and dose-dependently increased the doses of aconitine and ouabain required to induce the arrhythmia indexes. In coronary ligation induced rat arrhythmia model, resveratrol shortened duration of arrhythmia, decreased incidence of ventricular tachycardia and mortality. Electrophysiological experiment revealed that resveratrol could shorten APD through inhibition of ICa and selective enhancement of IKs without an effect on IKr.

Jagged1 protein enhances the differentiation of mesenchymal stem cells into cardiomyocytes.

BACKGROUND: Mesenchymal stem cells (MSCs) can differentiate into cardiomyocytes if an appropriate cellular environment is provided. Notch signals exchanged between neighboring cells through the Notch receptor can eventually dictate cell differentiation. In our study, we show that MSC differentiation into cardiomyocytes is dependent on the Notch signal. METHODS: We created a myocardial infarction model in rat by coronary ligation, administered direct intramyocardial injection of DAPI-labeled MSC immediately, and observed the differentiation of MSCs after 14 days by immunofluorescence staining against troponin T. We cultured MSCs and cardiomyocytes in four ways, respectively, in vitro. (1) MSCs cocultured with cardiomyocytes obtained from neonatal rat ventricles in a ratio of 1:10. (2) The two types of cells were cultured in two chambers separated by a semipermeable membrane as indirect coculture group. (3) Notch receptor-soluble jagged1 protein was added to indirect coculture group. (4) Both jagged1 protein and gamma-secretase inhibitor-DAPT were added to indirect coculture group. Two weeks later, we observed the differentiation percentage, respectively, by immunofluorescence staining. RESULTS: We found the differentiation of MSCs which were close to cardiomyocytes in vivo. The differentiation percentage of the four cell culture group was 30.13+/-2.16%, 12.52+/-1.18%, 26.33+/-2.20%, and 13.08+/-1.15%. CONCLUSIONS: MSCs can differentiate into cardiomyocytes in vitro and in vivo if a cardiomyocyte microenvironment is provided. 2. Cell-to-cell interaction is very important for the differentiation of MSCs into cardiomyocytes. 3. Jagged1 protein can activate Notch signal and enhance the differentiation of MSC into cardiomyocyte, while the effect can be inhibited by DAPT.