Inhibition of TRPM7 Attenuates Rat Aortic Smooth Muscle Cell Proliferation Induced by Angiotensin II: Role of Genistein

Circ_0021155 can participate in the phenotypic transformation of human vascular smooth muscle cells via the miR-4459/TRPM7 axis

The phenotypic transformation of vascular smooth muscle cells (VSMCs) plays a key role in the pathological process of atherosclerosis (AS), and TRPM7 is involved in this process. In this study, we verified whether circRNAs participate in the phenotypic transformation of VSMCs by regulating TRPM7 in AS. The RNA-sequencing data of atherosclerosis were downloaded and analysed from the GEO database. Only hsa_circ_0021155 related to TRPM7 was differentially expressed in AS. circRNA distribution and expression were observed via FISH and PCR. CCK8, scratch test and Transwell assay were used to observe the proliferation and migration of cells. Western blot was performed to examine changes in α-actin, calponin, SMMHC and TRPM7 proteins. The expression of hsa_circ_0021155 against has-miR-4459/miR-3689c was verified via PCR. The ceRNA relationship of TPRM7-miR4459-circ0021155 was verified via dual luciferase assay, and the effects of miR4459 mimic/inhibitor on the proliferation of cells were further observed. The expression of hsa_circ_0021155 and OX-LDL was increased in VSMCs. hsa_circ_0021155 promoted the expression of TRPM7 and inhibited the protein expression of α-actin, calponin and SMMHC. In addition, it promoted the proliferation and migration of cells and inhibited the expression of miR-3689c and miR-4459 but did not affect miR-4756-5p. The dual luciferase assay showed that circ0021155-miR4459-TRPM7 mRNA was highly compatible and could be mutually regulated by a ceRNA network. In conclusion, hsa_circ_0021155 regulates the proliferation, migration and phenotype transformation of VSMCs induced by OX-LDL via the miR-4459/TRPM7 axis. hsa_circ_0021155 and TRPM7 may offer novel therapeutic targets for atherosclerosis.

Thymoquinone suppresses platelet-derived growth factor-BB-induced vascular smooth muscle cell proliferation, migration and neointimal formation

The excessive proliferation and migration of vascular smooth muscle cells (VSMCs) are mainly responsible for vascular occlusion diseases, such as pulmonary arterial hypertension and restenosis. Our previous study demonstrated thymoquinone (TQ) attenuated monocrotaline‐induced pulmonary arterial hypertension. The aim of the present study is to systematically examine inhibitory effects of TQ on platelet‐derived growth factor‐BB (PDGF‐BB)–induced proliferation and migration of VSMCs in vitro and neointimal formation in vivo and elucidate the potential mechanisms. Vascular smooth muscle cells were isolated from the aorta in rats. Cell viability and proliferation were measured in VSMCs using the MTT assay. Cell migration was detected by wound healing assay and Transwell assay. Alpha‐smooth muscle actin (α‐SMA) and Ki‐67‐positive cells were examined by immunofluorescence staining. Reactive oxygen species (ROS) generation and apoptosis were measured by flow cytometry and terminal deoxyribonucleotide transferase–mediated dUTP nick end labelling (TUNEL) staining, respectively. Molecules including the mitochondria‐dependent apoptosis factors, matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), PTEN/AKT and mitogen‐activated protein kinases (MAPKs) were determined by Western blot. Neointimal formation was induced by ligation in male Sprague Dawley rats and evaluated by HE staining. Thymoquinone inhibited PDGF‐BB–induced VSMC proliferation and the increase in α‐SMA and Ki‐67‐positive cells. Thymoquinone also induced apoptosis via mitochondria‐dependent apoptosis pathway and p38MAPK. Thymoquinone blocked VSMC migration by inhibiting MMP2. Finally, TQ reversed neointimal formation induced by ligation in rats. Thus, TQ is a potential candidate for the prevention and treatment of occlusive vascular diseases.

Role of ROS-TRPM7-ERK1/2 axis in high concentration glucose-mediated proliferation and phenotype switching of rat aortic vascular smooth muscle cells

This study investigated the change of transient receptor potential cation channel subfamily M member 7 (TRPM7) expression in rat aortic vascular smooth muscle cells (RAoSMCs) treated with a high concentration of d-glucose (HG) and its role in promoting the proliferative phenotype of RAoSMCs. Chronic exposure to HG increased TRPM7 protein expression and TRPM7 whole-cell currents in RAoSMCs. By contrast, RAoSMC exposure to high concentration of l-glucose and mannital exhibited no such effect. Mechanistically, HG treatment elevated TRPM7 expression by increasing oxidative stress. Data also demonstrated that HG significantly promoted RAoSMC proliferation. In addition, as indicated by the changes of the expression of VSMC differentiation marker molecules, phenotype switching of RAoSMCs occurred during exposing to HG. TRPM7 knockdown partially blocked the HG effect on phenotype switching and RAoSMC proliferation. This phenomenon was achieved through inhibiting the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK signaling pathway. These observations suggest that reactive oxygen species-TRPM7-ERK1/2 axis plays an important role in hyperglycemia-induced development of the proliferative phenotype in RAoSMC.

TRPM7 channels mediate the functional changes in cardiac fibroblasts induced by angiotensin II

Transient receptor potential melastatin 7 (TRPM7), a bifunctional channel protein owning both cation permeability and kinase activity, plays an important role in the pathophysiological process of many cell types, such as vascular smooth muscle cells, human glioma cells and mouse cortical astrocytes. However, whether TRPM7 channels play a key role in the functional change of cardiac fibroblasts (CFs) induced by angiotensin II (Ang II) remains unknown. Using Cell Counting Kit-8 (CCK-8) assay, immunofluorescence assay, western blot analysis, RT-qPCR, RNA interference (RNAi) and whole-cell patch-clamp techniques, the present study aimed to explore the role of TRPM7 channels in the proliferation, differentiation and collagen synthesis of CFs induced by Ang II. Our data showed that Ang II time-dependently increased TRPM7 expression and TRPM7 currents in the CFs. Downregulation of TRPM7 attenuated the TRPM7 current density, and inhibited the proliferation, differentiation and collagen synthesis of CFs induced by Ang II. Our results identified the TRPM7 channel as a pivotal member associated with the functional change of CFs induced by Ang II, and suggest that the TRPM7 channel may represent a promising therapeutic strategy for the treatment of fibrosis-related cardiac diseases.

Hypotensive effects of genistein: From chemistry to medicine

Genistein (4', 5, 7-trihydroxyisoflavone), a naturally occurring flavonoid characteristic of Leguminoseae plants, is a phyto-oestrogen exerting oestrogenic activity as both an agonist and an antagonist substance. A large body of evidence suggests that genistein possesses many physiological and pharmacological properties that make this molecule a potential agent for the prevention and treatment of a number of chronic diseases. Growing evidence suggests that genistein could act as a vasodilating, anti-thrombotic, and anti-atherosclerotic agent, exerting these effects through different mechanisms of action. This paper aims to review data from the literature assessing the beneficial effects of genistein on hypertension, one of the most important cardiovascular disease risk factors along with hyperglycemia and hyperlidipemia. In addition, we discuss the chemistry, main sources and bioavailability of genistein. Scientific findings support genistein's potential as a promising anti-hypertensive agent in different experimental models. However, clinical trials are very limited and more research will be required before genistein intake can be recommended as part of therapies targeting raised blood pressure.