Suramin inhibits phenotypic transformation of vascular smooth muscle cells and neointima hyperplasia by suppressing transforming growth factor beta receptor 1 /Smad2/3 pathway activation

Vascular smooth muscle cells (VSMCs) contribute to neointimal hyperplasia (NIH) after vascular injury, a common feature of vascular remodelling disorders. Suramin is known to exert antitumour effects by inhibiting the proliferation of various tumour cells; however, its effects and mechanism on VSMCs remain unclear. This study investigated the effects of suramin on human aortic smooth muscle cells (HASMCs), rat aortic smooth muscle cells (RASMCs) and NIH to examine its suitability for the prevention of vascular remodelling disorders. In vitro, suramin administration reduced platelet-derived growth factor type BB (PDGF-BB)-stimulated proliferation, migration, and dedifferentiation of VSMCs through a transforming growth factor beta receptor 1 (TGFBR1)/Smad2/3-dependent pathway. Suramin dramatically inhibited NIH ligation in the left common carotid artery (LCCA) vivo. Therefore, our results indicate that suramin protects against the development of pathological vascular remodelling by attenuating VSMCs proliferation, migration, and phenotypic transformation and may be used as a potential medicine for the treatment of NIH.

Inhibition of neointima hyperplasia by the combined therapy of linagliptin and metformin via AMPK/Nox4 signaling in diabetic rats

BACKGROUND

Neointima hyperplasia is the pathological basis of atherosclerosis and restenosis which have been associated with diabetes mellitus (DM). It is controversial for linagliptin and metformin to protect against vascular neointimal hyperplasia caused by DM. Given the combined therapy of linagliptin and metformin in clinical practice, we investigated whether the combination therapy inhibited neointimal hyperplasia in the carotid artery in diabetic rats.

METHODS AND RESULTS

Neointima hyperplasia in the carotid artery was induced by balloon-injury in the rats fed with high fat diet (HFD) combined with low dose streptozotocin (STZ) administration. In vitro, vascular smooth muscle cells (VSMCs) were incubated with high glucose (HG, 30 mM) and the proliferation, migration, apoptosis and collagen deposition were analyzed in VSMCs. We found that the combined therapy, not the monotherapy of linagliptin and metformin significantly inhibited the neointima hyperplasia and improved the endothelium-independent contraction in the balloon-injured cardia artery of diabetic rats, which was associated with the inhibition of superoxide (O₂^-.) production in the cardia artery. In vitro, HG-induced VSMC remodeling was shown as the remarkable upregulation of PCNA, collagan1, MMP-9, Bcl-2 and migration rate as well as the decreased apoptosis rate. Such abnormal changes were dramatically reversed by the combined use of linagliptin and metformin. Moreover, the AMP-activated protein kinase (AMPK)/Nox4 signal pathway was found to mediate VSMC remodeling responding to HG. Linagliptin and metformin were synergistical to target AMPK/Nox4 signal pathway in VSMCs incubated with HG and in the cardia artery of diabetic rats, which was superior to the monotherapy.

CONCLUSIONS

We demonstrated that the potential protection of the combined use of linagliptin and metformin on VSMC remodeling through AMPK/Nox4 signal pathway, resulting in the improvement of neointima hyperplasia in diabetic rats. This study provided new therapeutic strategies for vascular stenosis associated with diabetes.

Inhibition of vascular neointima hyperplasia by FGF21 associated with FGFR1/Syk/NLRP3 inflammasome pathway in diabetic mice

BACKGROUND AND AIMS

Neointima hyperplasia is the pathological basis of atherosclerosis and restenosis, which have been associated with diabetes mellitus (DM). Fibroblast growth factor 21 (FGF21) is a potential diabetic drug, however, it has not been investigated whether FGF21 prevents neointima hyperplasia in DM.

METHODS

Vascular neointima hyperplasia was induced in mice fed a high fat diet (HFD) combined with low dose streptozotocin (STZ) administration. In vitro, vascular smooth muscle cells (VSMCs) were incubated with high glucose (HG, 30 mM). VSMC proliferation and migration, as well as formation of NLRP3 inflammasome, were assessed.

RESULTS

We found that FGF21 significantly inhibited neointima hyperplasia and improved endothelium-independent contraction in the wire-injured common carotid artery (CCA) of diabetic mice. In vitro, the proliferation and migration of HG-treated VSMCs were shown as remarkable increase of PCNA, cyclin D1, MMP2 and MMP9, as well as cell migration through wound healing and transwell migration assays. Such abnormal changes were dramatically reversed by FGF21, which mimicked the role of NLRP3 inflammasome inhibitor MCC950 and caspase-1 inhibitor WEHD. Moreover, along with more NLRP3, ASC oligomer and their colocalization, the release of active caspase-1(p20) and IL-1β was significantly inhibited by FGF21 in VSMCs exposed to HG. Furthermore, FGF21 suppressed phosphorylation of spleen tyrosine kinase (Syk) via FGFR1, which regulated NLRP3 inflammasome through ASC phosphorylation and oligomerization.

CONCLUSIONS

We demonstrated that potential protection of FGF21 on VSMCs proliferation and migration was associated with inhibition of FGFR1/Syk/NLRP3 inflammasome, resulting in the improvement of neointima hyperplasia in diabetic mice.

Anti-proliferative and anti-migratory effects of Scutellaria strigillosa Hemsley extracts against vascular smooth muscle cells

ETHNOPHARMACOLOGICAL RELEVANCE

The abnormal increase in vascular smooth muscle cell (VSMC) proliferation and migration are critical events in the pathogenesis of cardiovascular diseases (CVDs) including restenosis and atherosclerosis. The dried roots of Scutellaria baicalensis Georgi (common name: Huangqin in China) have been confirmed to possess beneficial effects on CVD by clinical and modern pharmacological studies. Flavonoids in Huangqin exert anti-proliferative and anti-migratory effects. Similar to Huangqin, Scutellaria strigillosa Hemsley (SSH) has been used to clear heat and damp and is especially rich in flavonoids including wogonin, wogonoside, baicalein, and baicalin. However, there have been few of reports about pharmacological activities of SSH.

AIM OF THE STUDY

To investigate the anti-proliferative and anti-migratory properties of Scutellaria strigillosa Hemsley extract (SSHE) in vitro and in vivo and explore its possible mechanism of action.

MATERIALS AND METHODS

The chemical constituents of SSHE were analyzed by ultra-high performance liquid chromatography coupled with triple time-of-flight mass spectrometry (UPLC-Triple-TOF-MS/MS). Cell proliferation and migration were investigated using BrdU incorporation assay and cell scratch test, respectively. The protein expression was determined by western blotting. In vivo, we established an artery ligation model of C57BL/6 mice and orally administered them with 50 or 100 mg/kg/day of SSHE. The carotid arteries were harvested and the intima-media thickness was examined 28 days post-ligation.

RESULTS

Twelve compounds were identified and tentatively characterized. SSHE significantly inhibited the VSMC proliferation and migration stimulated by PDGF-BB and decreased the relative protein expression of regulatory signaling intermediates. Furthermore, the expression of SM22α was significantly elevated in SSHE-pretreated VSMCs, whereas knockdown of SM22α impaired the PDGF-BB-induced proliferation and migration arrest. Meanwhile, both ROS generation and the phosphorylation of ERK decreased in SSHE-pretreated VSMCs. In carotid artery ligation mice model, SSHE treatment significantly inhibited neointimal hyperplasia.

CONCLUSIONS

SSHE significantly inhibited the PDGF-BB-induced VSMC proliferation, migration, and neointimal hyperplasia of carotid artery caused by ligation. Upregulation of SM22α expression, inhibition of ROS generation and ERK phosphorylation were, at least, partly responsible for the effects of SSHE on VSMCs.

Mouse Model of Wire Injury-Induced Vascular Remodeling

We introduced the vascular remodeling mouse system induced by the wire injury to investigate the molecular and cellular mechanisms of cardiovascular diseases. Using these models, we focus on the adventitial cell population in the outermost layer of the adult vasculature as a vascular progenitor niche. Firstly we used the standard wire injury approach, leaving the wire for 1 min in the artery and retracting the wire by twisting out to expand the artery and denude the inner layer endothelial cells in the both peripheral artery and femoral artery. This method leads to adventitial lineage cell accumulation on the medial-adventitial border, but no contribution into the hyperplastic neointima. Since advanced atherosclerotic plaques in the mouse models and human clinical specimens show the elastic lamina in the media broken, we hypothesized that adventitial lineage cells contribute to acute neointima formation induced by the mechanical damage in both endothelial and medial layers. To make this intensive damage, next, we used the bigger diameter wire with no hydrophilic coating and repeated the ten-times insertion and retraction of the wire after leaving for 1 min in the femoral artery. The additional ten-times intensive movements of the wire lead to breakdown and rupture of the elastic lamina together with a contribution of adventitial lineage cells to the hyperplastic neointima. Here we describe these two different wire injury methods to induce different types of vascular remodeling at the point of adventitial lineage cell contribution to the hyperplastic neointima by targeting two separate locations of hind limb artery, the peripheral artery and femoral artery, and using two different diameter wires.

B cell translocation gene, a direct target of miR-142-5p, inhibits vascular smooth muscle cell proliferation by down-regulating cell cycle progression

Vascular smooth muscle cell (VSMC) proliferation plays a key role in neointimal hyperplasia and restenosis. Here we report the role of the microRNA miR-142-5p and its downstream target genes on the proliferation of cultured VSMCs. miR-142-5p promoted VSMC proliferation by down-regulating B cell translocation gene 3 (BTG3). We found that BTG3 inhibited the expression of cell cycle regulatory genes and cell growth. As shown by luciferase reporter assay, miR-142-5p bound directly to the 3'-untranslated region of BTG3. Overexpression of miR-142-5p induced expression of cell cycle regulatory genes. Thus, BTG3, a novel, direct target of miR-142-5p, negatively regulates VSMC proliferation.