Guanhua Xue

Essential role of Pin1 via STAT3 signalling and mitochondria-dependent pathways in restenosis in type 2 diabetes

Type 2 diabetes (T2D) is associated with accelerated restenosis rates after angioplasty. We have previously proved that Pin1 played an important role in vascular smooth muscle cell (VSMC) cycle and apoptosis. But neither the role of Pin1 in restenosis by T2D, nor the molecular mechanism of Pin1 in these processes has been elucidated. A mouse model of T2D was generated by the combination of high‐fat diet (HFD) and streptozotocin (STZ) injections. Both Immunohistochemistry and Western blot revealed that Pin1 expression was up‐regulated in the arterial wall in T2D mice and in VSMCs in culture conditions mimicking T2D. Next, increased activity of Pin1 was observed in neointimal hyperplasia after arterial injury in T2D mice. Further analysis confirmed that 10% serum of T2D mice and Pin1‐forced expression stimulated proliferation, inhibited apoptosis, enhanced cell cycle progression and migration of VSMCs, whereas Pin1 knockdown resulted in the converse effects. We demonstrated that STAT3 signalling and mitochondria‐dependent pathways played critical roles in the involvement of Pin1 in cell cycle regulation and apoptosis of VSMCs in T2D. In addition, VEGF expression was stimulated by Pin1, which unveiled part of the mechanism of Pin1 in regulating VSMC migration in T2D. Finally, the administration of juglone via pluronic gel onto injured common femoral artery resulted in a significant inhibition of the neointima/media ratio. Our findings demonstrated the vital effect of Pin1 on the VSMC proliferation, cell cycle progression, apoptosis and migration that underlie neointima formation in T2D and implicated Pin1 as a potential therapeutic target to prevent restenosis in T2D.

Thrombospondin-4 ablation reduces macrophage recruitment in adipose tissue and neointima and suppresses injury-induced restenosis in mice.

OBJECTIVE Thrombospondin-4 (Thbs4) is a member of the extracellular calcium-binding protein family and is linked to cell adhesion and migration. Given the involvement of Thbs4 in vascular inflammation, we hypothesized that Thbs4 plays a role in restenosis. METHODS AND RESULTS Here we show evidence that Thbs4 is upregulated in wire-injured mouse arteries and correlated with CD68 expression. Macrophage infiltration is reduced in both adipose tissue (AT) and neointima of Thbs4/ApoE double knockout (DKO) mice after injury. Moreover, Thbs4 deficiency prevents restenosis in ApoE KO mice fed a Western-type diet (WTD). Lethally irradiated DKO mice that receive bone marrow from ApoE KO or DKO mice have reduced neointima development. While considering related mechanisms, we note decreased chemokine production in both AT and neointima of DKO mice. In addition, vascular smooth muscle cells (VSMCs) derived from DKO mice display suppressed proliferation and migration in comparison with controls. Thioglycollate (TG)-induced macrophages from DKO mice show retarded adhesion to VSMCs. Recombinant Thbs4 promoted macrophage adhesion to VSMCs, and enhanced VSMC proliferation and migration. CONCLUSION Collectively, these data highlight the significance of Thbs4 in regulating macrophage accumulation and treating restenosis.

STAT4 deficiency protects against neointima formation following arterial injury in mice

Signal transducer and activator of transcription 4 (STAT4) has been associated with susceptibility to autoimmune diseases. Intriguingly, we previously reported that STAT4 might play a critical role in vascular smooth muscle cell (VSMC) proliferation. The present study therefore investigated the impact of STAT4 on VSMC migration, apoptosis and neointimal hyperplasia postinjury, as well as the underlying mechanisms. Guide-wire injury was associated with development of intimal neointima, STAT4 and phosphorylated STAT4 (p-STAT4) expressions were apparently up-regulated in the injured arteries. Neointima was greatly blocked in STAT4 knockout (KO) mice compared with wild type (WT) mice. A marked loss of inflammatory cells was identified in the vasculature postinjury in STAT4 KO mice. VSMC apoptosis was enhanced in the vasculature postinjury in STAT4 KO mice compared with WT mice. Cultured primary STAT4 KO VSMCs displayed reduced migration in comparison with WT controls. Mechanically, the deletion of STAT4 potently decreased the level of MCP-1, and its downstream targets MMP1 and MMP2. The effect of STAT4 on VSMC apoptosis was mainly mediated by the activation of the mitochondrial apoptotic pathway, as manifested by increased cytochrome c release and the activation of caspase-3. STAT4 therefore represents a promising molecular target to limit restenosis after artery intervention.

Features analysis of lower extremity arterial lesions in 162 diabetes patients.

Objective. This study aimed to investigate the angiographic manifestations of lower extremity atherosclerotic steno-occlusive disease in patients with diabetes. Materials and Methods. A total of 162 patients with diabetes were enrolled in this study. The angiographic findings of lower extremity arterial lesions were evaluated according to location (iliac, femoral, popliteal, and crural artery), type (stenosis or occlusion), and length (<5 cm, 5–10 cm, and >5 cm). Results. A total of 131 of 162 (80.9%) diabetics showed multiple segmental lesions, and 19.1% (31/162) presented single segmental lesions in the lower extremity artery. Crural artery was the mainly involved location (39/162, 85.8%). Among the recorded 660 lesions of 162 cases, 437 (66.2%) were occlusion lesions, while 223 (33.8%) were stenosis lesions. Of 437 occlusion lesions, 308 lesions (70.5%) were in crural artery. More than 10 cm occlusion lesion (242/392, 61.7%) was the main manifestation in crural artery, especially in anterior (92/127, 67.2%) and posterior tibial arteries (91/124, 73.4%), which was higher than that in iliac artery (8/33, 24.2%), popliteal artery (53/157, 33.8%), and femoral artery (11/78, 14.1%). Conclusion. In diabetic subjects with lower limb artery ischemia, the vascular involvement is extremely diffuse and particularly severe in crural arteries, with high prevalence of more than 10 cm occlusion lesions.

MiR-3202 – Promoted H5V Cell Apoptosis by Directly Targeting Fas Apoptotic Inhibitory Molecule 2 (FAIM2) in High Glucose Condition

Background Vascular complications are a major concern for patients with diabetes. Endothelial cells (ECs) play a key role in vascular function. MicroRNAs (miRNAs) have been shown to play an important role in mediating EC function; miRNAs are vulnerable to hyperglycemic conditions. Previous reports verified that Fas apoptotic inhibitory molecule 2 (FAIM2) can inhibit cell apoptosis through repressing the FAS-associated death domain protein (FADD) pathway. This current study was designed to explore the potential involvement of miR-3202 in the pathogenesis of ECs in high-glucose conditions. Material/Methods The aim of this study was to investigate the role of miR-3202 in regulating hyperglycemia-induced ECs by targeting FAIM2. The endothelial cell line H5V was cultured in a high-glucose condition to induce damage to FAIM2 expression in ECs; mimic and inhibition of miR-3202 were used to enhance and depress miR-3202’s function to explore its function on FAIM2. Results Our study showed that FAIM2 was inhibited by high-glucose conditions, and miRNA-3202 was induced by high-glucose conditions. FAIM2 was identified as the target gene of miRNA-3202; luciferase reporter assays confirmed that FAIM2 was downregulated by miR-3202 directly, that is, miR-3202 can upregulate Fas/FADD through inhibiting FAIM2. Conclusions MiR-3202 can promote EC apoptosis in hyperglycemic conditions, which demonstrated that EC apoptosis induced by high-glucose conditions partly depends on miR-3202 targeting FAIM2.