Objective—: Vascular precursor cells with angiogenic potentials are important for tissue repair, which is impaired in diabetes mellitus. MicroRNAs are recently discovered key regulators of gene expression, but their role in vascular precursor cell–mediated angiogenesis in diabetes mellitus is unknown. We tested the hypothesis that the microRNA miR-27b rescues impaired bone marrow–derived angiogenic cell (BMAC) function in vitro and in vivo in type 2 diabetic mice. Approach and Results—: BMACs from adult male type 2 diabetic db/db and from normal littermate db/+ mice were used. miR-27b expression was decreased in db/db BMACs. miR-27b mimic improved db/db BMAC function, including proliferation, adhesion, tube formation, and delayed apoptosis, but it did not affect migration. Elevated thrombospondin-1 (TSP-1) protein in db/db BMACs was suppressed on miR-27b mimic transfection. Inhibition of miR-27b in db/+ BMACs reduced angiogenesis, which was reversed by TSP-1 small interfering RNA (siRNA). miR-27b suppressed the pro-oxidant protein p66 ^shc and mitochondrial oxidative stress, contributing to its protection of BMAC function. miR-27b also suppressed semaphorin 6A to improve BMAC function in diabetes mellitus. Luciferase binding assay suggested that miR-27b directly targeted TSP-1, TSP-2, p66 ^shc , and semaphorin 6A. miR-27b improved topical cell therapy of diabetic BMACs on diabetic skin wound closure, with a concomitant augmentation of wound perfusion and capillary formation. Normal BMAC therapy with miR-27b inhibition demonstrated reduced efficacy in wound closure, perfusion, and capillary formation. Local miR-27b delivery partly improved wound healing in diabetic mice. Conclusions—: miR-27b rescues impaired BMAC angiogenesis via TSP-1 suppression, semaphorin 6A expression, and p66shc-dependent mitochondrial oxidative stress and improves BMAC therapy in wound healing in type 2 diabetic mice.

Impaired angiogenesis and its induced refractory wound lesions are common complications of diabetes. Hydrogen sulfide (H₂S) has been reported to have proangiogenic effects. We hypothesize that H₂S improves diabetic wound healing by restoring endothelial progenitor cell (EPC) function in type 2 diabetes. db/db Mice were treated with sodium hydrosulfide (NaHS), 4-hydro-xythiobenzamide group (HTB), or saline for 18 days. db/+ Mice were treated with dl-propargylglycine (PAG) or saline for 18 days. Plasma H₂S levels were significantly decreased in db/db mice and restored in the NaHS and HTB mice compared with the diabetic control group. Wound-closure rates were significantly faster in the NaHS and HTB groups than in the db/db group, in which the PAG group had slower wound-closure rates. Wound skin capillary densities were enhanced in the NaHS and HTB groups. EPC functions were significantly preserved in the NaHS and HTB groups but were decreased in the PAG group. Meanwhile, EPC functions of the db/+ mice were significantly reduced after in vitro PAG treatment or cystathionine-γ-lyase (CSE) silencing; EPC functions of db/db mice were significantly improved after in vitro NaHS treatment. The expressions of Ang-1 in wound skin tissue and in EPCs were upregulated in the NaHS and HTB groups compared with db/db controls, but were downregulated by in vivo PAG and in vitro siCSE treatment compared with normal controls. Diabetic EPC tube formation capacity was significantly inhibited by Ang-1 small interfering RNA before NaHS treatment compared with db/db EPCs treated with NaHS only. Taken together, these results show that H₂S improves wound healing by restoration of EPC functions and activation of Ang-1 in type 2 diabetic mice.

Metformin, a well‐known AMPK agonist, has been widely used as the first‐line drug for treating type 2 diabetes. There had been a significant concern regarding the use of metformin in people with cardiovascular diseases (CVDs) due to its potential lactic acidosis side effect. Currently growing clinical and preclinical evidence indicates that metformin can lower the incidence of cardiovascular events in diabetic patients or even non‐diabetic patients beyond its hypoglycaemic effects. The underlying mechanisms of cardiovascular benefits of metformin largely involve the cellular energy sensor, AMPK, of which activation corrects endothelial dysfunction, reduces oxidative stress and improves inflammatory response. In this minireview, we summarized the clinical evidence of metformin benefits in several widely studied cardiovascular diseases, such as atherosclerosis, ischaemic/reperfusion injury and arrhythmia, both in patients with or without diabetes. Meanwhile, we highlighted the potential AMPK‐dependent mechanisms in in vitro and/or in vivo models.

As one of the cornerstones of clinical cardiovascular disease treatment, statins have an extensive range of applications. However, statins commonly used have side reactions, especially muscle-related symptoms (SAMS), such as muscle weakness, pain, cramps, and severe condition of rhabdomyolysis. This undesirable muscular effect is one of the chief reasons for statin non-adherence and/or discontinuation, contributing to adverse cardiovascular outcomes. Moreover, the underlying mechanism of muscle cell damage is still unclear. Here, we discovered that ferroptosis, a programmed iron-dependent cell death, serves as a mechanism in statin-induced myopathy. Among four candidates including atorvastatin, lovastatin, rosuvastatin, and pravastatin, only atorvastatin could lead to ferroptosis in human cardiomyocytes (HCM) and murine skeletal muscle cells (C2C12), instead of human umbilical vein endothelial cell (HUVEC). Atorvastatin inhibits HCM and C2C12 cell viability in a dose-dependent manner, accompanying with significant augmentation in intracellular iron ions, reactive oxygen species (ROS), and lipid peroxidation. A noteworthy investigation found that those alterations particularly occurred in mitochondria and resulted in mitochondrial dysfunction. Biomarkers of myocardial injury increase significantly during atorvastatin intervention. However, all of the aforementioned enhancement could be restrained by ferroptosis inhibitors. Mechanistically, GSH depletion and the decrease in nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione peroxidase 4 (GPx4), and xCT cystine–glutamate antiporter (the main component is SLC7A11) are involved in atorvastatin-induced muscular cell ferroptosis and damage. The downregulation of GPx4 in mitochondria-mediated ferroptosis signaling may be the core of it. In conclusion, our findings explore an innovative underlying pathophysiological mechanism of atorvastatin-induced myopathy and highlight that targeting ferroptosis serves as a protective strategy for clinical application.

Background: Endothelial dysfunction enhances vascular inflammation, which initiates pulmonary arterial hypertension (PAH) pathogenesis, further induces vascular remodeling and right ventricular failure. Activation of inflammatory caspases is an important initial event at the onset of pyroptosis. Studies have shown that caspase-1–mediated pyroptosis has played a crucial role in the pathogenesis of PAH. However, the role of caspase-11, another inflammatory caspase, remains to be elucidated. Therefore, the purpose of this study was to clarify the role of caspase-11 in the development of PAH and its mechanism on endothelial cell function. Methods: The role of caspase-11 in the progression of PAH and vascular remodeling was assessed in vivo. In vitro, the effect of caspase-4 silencing on the human pulmonary arterial endothelial cells pyroptosis was determined. Results: We confirmed that caspase-11 and its human homolog caspase-4 were activated in PAH animal models and TNF (tumor necrosis factor)-α–induced human pulmonary arterial endothelial cells. Caspase-11 ^−/− relieved right ventricular systolic pressure, right ventricle hypertrophy, and vascular remodeling in Sugen-5416 combined with chronic hypoxia mice model. Meanwhile, pharmacological inhibition of caspase-11 with wedelolactone exhibited alleviated development of PAH on the monocrotaline-induced rat model. Moreover, knockdown of caspase-4 repressed the onset of TNF-α–induced pyroptosis in human pulmonary arterial endothelial cells and inhibited the activation of pyroptosis effector GSDMD (gasdermin D) and GSDME (gasdermin E). Conclusions: These observations identified the critical role of caspase-4/11 in the pyroptosis pathway to modulate pulmonary vascular dysfunction and accelerate the progression of PAH. Our findings provide a potential diagnostic and therapeutic target in PAH.

High mobility group box 1 (HMGB1) plays an important role in the pathologic processes of endothelial permeability under oxidative stress. Trophoblast oxidative stress has been implicated in the pathophysiology of preeclampsia (PE). HMGB1 serum levels are increased in PE. However, the potential roles of HMGB1 in endothelial permeability in PE remain unclear. We assessed the effects of the hypoxic trophoblast on the permeability of the endothelial monolayer. Our results showed that the hypoxic trophoblast displayed higher HMGB1 mRNA, intracellular HMGB1 protein, and HMGB1 in conditioned medium than those of the normoxic trophoblast did. The hypoxic trophoblast conditioned medium increased the endothelial monolayer permeability and increased TLR 4 and caveolin-1 (CAV-1) protein expression in endothelial cells, which was inhibited by glycyrrhizic acid and HMGB1 small interfering RNA transfection to trophoblasts before hypoxia. The increased endothelial permeability induced by hypoxic trophoblast conditioned medium could be inhibited with TLR4 or CAV-1 gene silencing in endothelial cells. Immunoprecipitation showed that CAV-1 and TLR4 are colocalized in HUVECs and C57BL/6 mouse kidney. TLR4 small interfering RNA suppressed CAV-1 protein expression in endothelial cells upon stimulation of hypoxic trophoblast conditioned medium or HMGB1. We conclude that hypoxic trophoblasts play an important role in the mechanism of general edema (including protein urine) in PE via increasing endothelial monolayer permeability through the HMGB1/TLR4/CAV-1 pathway.