Vascular smooth muscle cells (VSMCs) are essential for maintaining arterial wall integrity, with their associated apoptosis critically involved in cardiovascular diseases. Intracellular chloride anion (Cl-) dysregulation is closely linked to apoptosis. However, the underlying mechanism via chloride-sensitive kinases remains unclear. Here, we show that hypotonic stimulation activates volume-regulated chloride channels (VRCCs) and induces the phosphorylation of the chloride-sensitive kinase WNK1. Activated WNK1 protects VSMCs against H2O2-induced apoptosis by maintaining the Bcl-2/Bax balance, preserving mitochondrial membrane potential and inhibiting caspase-9/3 activation. These findings uncover a novel protective role of WNK1 in VRCC-mediated Cl- signalling and provide new perspectives for targeting chloride-sensitive kinases in the treatment of hypertension and related cardiovascular diseases.

Anti-vascular endothelial growth factor (anti-VEGF) therapies are effective treatment of severe diabetic retinopathy (DR) and macular edema, but a significant subset of people showed inadequate response to anti-VEGF intervention. Since elevation or overexpressing retinol binding protein 3 (RBP3) decreased risks for retinal pathologies and progression to severe DR, we compared the therapeutic profile of RBP3 and anti-VEGF to normalize retinal dysfunctions induced by diabetes. Intravitreous injection of recombinant human RBP3 (rhRBP3) and anti-VEGF antibodies (bevacizumab) inhibited retinal vascular permeability in Lewis rats induced by VEGF-A or after 2 months of diabetes induced by streptozotocin, in parallel with reductions of retinal VEGF and VEGFR2 expressions and tyrosine phosphorylation of VEGFR. Only rhRBP3 ameliorated diabetes induced reduction of neural retinal function, measured by electroretinogram. Further, rhRBP3 reduced retinal expressions of inflammatory cytokines (TNFα and IL6) in retinal pigmented epithelial and Müller cells exposed to hyperglycemia. Metabolic studies, using Seahorse, showed only rhRBP3 normalized retinal glycolytic rates in diabetic rats. Thus, both intravitreous anti-VEGF antibodies and RBP3 injections normalized retinal vascular dysfunctions caused by diabetes. Only RBP3 targeted both neural and vascular retina to reduce glycolytic rates, reversed neural-retinal dysfunctions, and reduced inflammatory cytokines induced by diabetes, to delay early changes of DR.

AIMS:Impairment of nitric oxide (NO) production is a major cause of endothelial dysfunction and hypertension. ClC-5 Cl- channel is abundantly expressed in the vascular endothelium. However, it remains unclear how it regulates endothelial function. MATERIALS AND METHODS:In this study, we used mice with a knockout of the Clcn5 gene encoding ClC-5 protein globally or specifically in vascular endothelium. KEY FINDINGS:ClC-5 knockout globally or specifically in vascular endothelium mitigates the elevation of mean blood pressure and impairment of endothelial dysfunction induced by Angiotensin II. This effect is mediated by the reversal of the impairment of NO production after the stimulation of the Akt/endothelial nitric oxide synthase (eNOS) signal pathway. Application of a low Cl- extracellular solution onto endothelial cells stimulates a ClC-5-dependent current and lowered intracellular Cl- concentration, which activates with-no-lysine (K)-1 (WNK1), a Cl--sensitive kinase. Silencing ClC-5 or WNK1 expression rescues the impairment of endothelial NO production induced by a low Cl- solution. In contrast, overexpression of ClC-5 or WNK1 led to the opposite results. WNK1, found to be associated with Rho-specific guanine nucleotide dissociation inhibitor (RhoGDI), increases RhoA activity, and thereby inhibits the endothelial Akt/eNOS signaling pathway. SIGNIFICANCE:ClC-5 knockout mitigates Ang II-induced hypertension and endothelial dysfunction by promoting NO production via regulating WNK1/RhoA/Akt/eNOS signaling pathway. The results may be useful for developing novel treatments of endothelial dysfunction associated-diseases.

Hypertensive cerebrovascular remodeling involves the enlargement of vascular smooth muscle cells (VSMCs), which activates volume-regulated Cl- channels (VRCCs). The leucine-rich repeat-containing family 8 A (LRRC8A) has been shown to be the molecular identity of VRCCs. However, its role in vascular remodeling during hypertension is unclear. In this study, we used vascular smooth muscle-specific LRRC8A knockout (CKO) mice and an angiotensin II (Ang II)-induced hypertension model. The results showed that cerebrovascular remodeling during hypertension was ameliorated in CKO mice, and extracellular matrix (ECM) deposition was reduced. Based on the RNA-sequencing analysis of aortic tissues, the level of matrix metalloproteinases (MMPs), such as MMP-9 and MMP-14, were reduced in CKO mice with hypertension, which was further verified in vivo by qPCR and immunofluorescence analysis. Knockdown of LRRC8A in VSMCs inhibited the Ang II-induced upregulation of collagen I, fibronectin, and matrix metalloproteinases (MMPs), and overexpression of LRRC8A had the opposite effect. Further experiments revealed an interaction between with-no-lysine (K)-1 (WNK1), which is a "Cl--sensitive kinase", and Forkhead transcription factor O3a (FOXO3a), which is a transcription factor that regulates MMP expression. Ang II induced the phosphorylation of WNK1 and downstream FOXO3a, which then increased the expression of MMP-2 and MMP-9. This process was inhibited or potentiated when LRRC8A was knocked down or overexpressed, respectively. Overall, these results demonstrate that LRRC8A knockout in vascular smooth muscle protects against cerebrovascular remodeling during hypertension by reducing ECM deposition and inhibiting the WNK1/FOXO3a/MMP signaling pathway, demonstrating that LRRC8A is a potential therapeutic target for vascular remodeling-associated diseases such as stroke.

[This corrects the article DOI: 10.1016/j.apsb.2021.04.013.].

Background and Purpose: Atherosclerosis induced by cyclosporine A (CsA), an inhibitor of the calcineurin/nuclear factor of activated T cells (NFAT) pathway, is a major concern after organ transplantation. However, the atherosclerotic mechanisms of CsA remain obscure. We previously demonstrated that calcineurin/NFAT signalling inhibition contributes to atherogenesis via suppressing microRNA-204 (miR-204) transcription. We therefore hypothesised that miR-204 is involved in the development of CsA-induced atherosclerosis.Experimental Approach: ApoE(-/-) mice with macrophage-miR-204 overexpression were generated to determine the effects of miR-204 on CsA-induced atherosclerosis. Luciferase reporter assays and chromatin immunoprecipitation sequencing were performed to explore the targets mediating miR-204 effects.Key Results: CsA alone did not significantly affect atherosclerotic lesions or serum lipid levels. However, it exacerbated high-fat diet-induced atherosclerosis and hyperlipidemia in C57BL/6J and ApoE(-/-) mice, respectively. miR-204 levels decreased in circulating monocytes and plaque lesions during CsA-induced atherosclerosis. The upregulation of miR-204 in macrophages inhibited CsA-induced atherosclerotic plaque formation but did not affect serum lipid levels. miR-204 limited the CsA-induced foam cell formation by reducing the expression of the scavenger receptors SR-BII and CD36. SR-BII was post-transcriptionally regulated by mature miR-204-5p via 3 ' -UTR targeting. Additionally, nuclear-localised miR-204-3p prevented the CsA-induced binding of Ago2 to the CD36 promoter, suppressing CD36 transcription. SR-BII or CD36 expression restoration dampened the beneficial effects of miR-204 on CsA-induced atherosclerosis.Conclusion and Implications: Macrophage miR-204 ameliorates CsA-induced atherosclerosis, suggesting that miR-204 may be a potential target for the prevention and treatment of CsA-related atherosclerotic side effects.

Background: Current evidence suggests that Gamma-aminobutyric acid (GABA) receptors are associated with the occurrence and progression of cerebrovascular diseases. The present study investigated the association between single nucleotide polymorphisms (SNPs) in the Gamma-aminobutyric acid type A receptor gamma2 subunit (GABRG2) gene and ischemic stroke (IS). Methods: A total of 120 healthy volunteers and 187 patients with IS were recruited. Patients underwent complete neurological assessment and classification with the National Institute of Health Stroke Scale (NIHSS) and the Trial of ORG 10172 in Acute Stroke Treatment (TOAST). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to analyze SNP sites in 4 different regions (rs211037, rs418210, rs211035, and rs424740) of the GABRG2 gene. SHEsis online platform was used to assess SNP allele and genotype frequencies. Multivariate logistic regression analysis was performed to identify the risk factors for IS. Results: Univariate analysis showed that the T allele and TT genotype distribution for rs211037 were significantly more frequent in the IS group compared to controls (pallele = 0.01, odds ratio (OR) = 1.673, 95% confidence intervals (CI), 1.119–2.500, pgenotype = 0.03). Furthermore, multivariate logistic regression analysis revealed the TT genotype for rs211037 was an independent risk factor for IS (p = 0.017, OR = 1.925, 95% CI, 1.122–3.303). Age was also found to be an independent risk factor, and the older the age, the higher the risk of IS (p = 0.001, OR = 1.047, 95% CI, 1.020–1.073). Finally, subgroup analysis revealed that patients with the rs211037 TT genotype were associated with a higher NIHSS score (p = 0.03), and that large-artery atherosclerosis (LAA) subtype was predominant in patients with the rs211037 TT genotype (p = 0.042). Conclusions: These findings suggest the rs211037 polymorphism in the GABRG2 gene is an independent risk factor for IS in the Chinese population. GABRG2 could thus be a potential biomarker to assess the risk of IS.

[This corrects the article DOI: 10.1016/j.apsb.2021.04.013.].

BACKGROUND Alzheimer's disease (AD) is a type of disease frequently occurs in the elderly population. Diagnosis and treatment methods for this disease are still lacking, and more research is required. In addition, little is known about the function of the circular RNAs (circRNAs) in AD. METHODS In this research, RNA expression data of AD from the Gene Expression Omnibus (GEO) database were downloaded. The expression levels of circRNAs in cerebrospinal fluid samples of healthy participants and AD patients were measured by reverse transcription‑quantitative PCR (RT-qPCR). The diagnosed value of differential expressed circRNAs was analyzed with the Receiver operating characteristic curve (ROC). Pathways related to circ_0001535 were found using gene set enrichment analysis (GSEA) and Metascape. The direct interactions between circ_0001535 and E2F transcription factor 1 (E2F1) or E2F1 and dihydrofolate reductase (DHFR) were verified using Chromatin immunoprecipitation (ChIP) and RNA Binding Protein Immunoprecipitation (RIP) assays. Cell Counting Kit-8 (CCK8) and flow cytometry were used to identify the function of circ_0001535/E2F1/DHFR axis on the proliferation and apoptosis of AD cells. RESULTS In total, 12 circRNAs have been linked to AD diagnosis. The expression levels of 7 circRNAs differed between AD patients and control groups. Circ_0001535 had the most diagnose value among these circRNAs. Hence, circ_0001535 was regarded as a key circRNA in the present study. E2F1/DHFR axis was predicted to be regulated by circ_0001535. In addition, IP assays experiment results showed that E2F1 could bind to the promoter region of DHFR and be regulated by circ_0001535. In vitro results showed that circ_0001535 overexpression could promote DHFR expression, while E2F1 knock down could inhibit DHFR expression in SH-SY5Y cells. Finally, rescue experiments suggested that circ_0001535 could reduce Aβ25-35-induced SH-SY5Y cell proliferation and facilitate apoptosis through E2F1/DHFR axis. CONCLUSIONS Our research in AD circRNA can offer important information regarding the role of specific circRNAs in the AD environment and point to specific future areas of therapeutic intervention in AD.

Chronic inflammation of white adipose tissue is a key link between obesity and the associated metabolic syndrome. Transient receptor potential melastatin-like 7 (TRPM7) is known to be related to inflammation; however, the role of TRPM7 in adipocyte phenotype and function in obesity remains unclear. Here, we observe that the activation of adipocyte TRPM7 plays an essential role in pro-inflammatory responses. Adult male mice are used in our experiments. Adipocyte-specific deficiency in TRPM7 attenuates the pro-inflammatory phenotype, improves glucose homeostasis, and suppresses weight gain in mice fed a high-fat diet. Mechanistically, the pro-inflammatory effect of TRPM7 is dependent on Ca2+ signaling. Ca2+ influx initiated by TRPM7 enhances transforming growth factor-β activated kinase 1 activation via the co-regulation of calcium/calmodulin-dependent protein kinase II and tumor necrosis factor receptor-associated factor 6, leading to exacerbated nuclear factor kappa B signaling. Additionally, obese mice treated with TRPM7 inhibitor are protected against obesity and insulin resistance. Our results demonstrate TRPM7 as a factor in the development of adipose inflammation that regulates insulin sensitivity in obesity.

Background: Low serum chloride (Cl−) level is considered an independent predictor of cardiovascular mortality associated with chronic hypertension. However, the underlying mechanisms are unknown. ClC-5, a member of the Cl− channel family, is sensitive to changes in intracellular and extracellular Cl− concentration and conducts outwardly rectifying Cl− currents. The aims of this study were to determine if ClC-5 is regulated by low extracellular Cl−, clarify its putative roles in hypertension-induced cerebrovascular remodeling, and elucidate the associated underlying mechanisms. Methods: Whole-cell patch technique, intracellular Cl− concentration measurements, flow cytometry, Western blot, Clcn5 knockdown (Clcn5−/y), and adenovirus-mediated ClC-5 overexpression mice, 2-kidney, 2-clip, and angiotensin II infusion–induced hypertensive models were used. Results: We found that low extracellular Cl− evoked a ClC-5–dependent Cl− current that was abolished by ClC-5 depletion in basilar artery smooth muscle cells (BASMCs). ClC-5 was upregulated in the arterial tissues of rats and patients with hypertension. Low Cl−–induced current and ClC-5 protein expression positively correlated with basilar artery remodeling during hypertension. ClC-5 knockdown ameliorated hypertension-induced cerebrovascular remodeling and smooth muscle cell proliferation, whereas ClC-5 overexpression mice exhibited the opposite phenotype. ClC-5–dependent Cl− efflux induced by low extracellular Cl− activated WNK1 (lysine-deficient protein kinase 1) which, in turn, activated AKT (protein kinase B), and culminated in BASMC proliferation and vascular remodeling. Conclusions: ClC-5 mediates low extracellular Cl–induced Cl− currents in BASMCs and regulates hypertension-induced cerebrovascular remodeling by promoting BASMC proliferation via the WNK1/AKT signaling pathway.

AIMS Our previous study demonstrated that Ca2+ influx through the Orai1 store-operated Ca2+ channel in macrophages contributes to foam cell formation and atherosclerosis via the calcineurin-ASK1 pathway, not the classical calcineurin-nuclear factor of activated T-cell (NFAT) pathway. Moreover, up-regulation of NFATc3 in macrophages inhibits foam cell formation, suggesting that macrophage NFATc3 is a negative regulator of atherogenesis. Hence, this study investigated the precise role of macrophage NFATc3 in atherogenesis. METHODS AND RESULTS Macrophage-specific NFATc3 knockout mice were generated to determine the effect of NFATc3 on atherosclerosis in a mouse model of adeno-associated virus-mutant PCSK9-induced atherosclerosis. NFATc3 expression was decreased in macrophages within human and mouse atherosclerotic lesions. Moreover, NFATc3 levels in peripheral blood mononuclear cells from atherosclerotic patients were negatively associated with plaque instability. Furthermore, macrophage-specific ablation of NFATc3 in mice led to the atherosclerotic plaque formation, whereas macrophage-specific NFATc3 transgenic mice exhibited the opposite phenotype. NFATc3 deficiency in macrophages promoted foam cell formation by potentiating SR-A- and CD36-meditated lipid uptake. NFATc3 directly targeted and transcriptionally up-regulated miR-204 levels. Mature miR-204-5p suppressed SR-A expression via canonical regulation. Unexpectedly, miR-204-3p localized in the nucleus and inhibited CD36 transcription. Restoration of miR-204 abolished the proatherogenic phenotype observed in the macrophage-specific NFATc3 knockout mice, and blockade of miR-204 function reversed the beneficial effects of NFATc3 in macrophages. CONCLUSION Macrophage NFATc3 up-regulates miR-204 to reduce SR-A and CD36 levels, thereby preventing foam cell formation and atherosclerosis, indicating that the NFATc3/miR-204 axis may be a potential therapeutic target against atherosclerosis.

Recent studies revealed LRRC8A to be an essential component of volume‐regulated anion channel (VRAC), which regulates cellular volume homeostasis. However, evidence for the contribution of LRRC8A‐dependent VRAC activity in vascular smooth muscle cells (VSMCs) is still lacking, and the relevant functional role of LRRC8A in VSMCs remains unknown. The primary goal of this study was to elucidate the role of LRRC8A in VRAC activity in VSMCs and the functional role of LRRC8A in cerebrovascular remodeling during hypertension.

Hypotonic stimulus enlarges cell volume and increased cell proliferation with the exact mechanisms unknown. Glucocorticoid-induced kinase-1 (SGK1) is a serine/threonine kinase that can be regulated by osmotic pressure. We have revealed that SGK1 was activated by hypotonic solution-induced lowering of intracellular Cl- concentration. Therefore, we further examined whether SGK1 mediated hypotonic solution-induced proliferation and the internal mechanisms in basilar smooth muscle cells (BASMCs). In the present study, BrdU incorporation assay, flow cytometry, western blotting were performed to evaluate cell viability, cell cycle transition, and the expression of cell cycle regulators and other related proteins. We found that silence of SGK1 largely blunted hypotonic challenge-induced increase in cell viability and cell cycle transition from G0/G1 phase to S phase, whereas overexpression of SGK1 showed the opposite effects. The effect of SGK1 on proliferation was related to the upregulation of cyclin D1 and cyclin E1, and the downregulation of p27 and p21, which is mediated by the interaction between SGK1 and cAMP responsive element-binding protein (CREB). Moreover, we overexpressed ClC-3 Cl- channel to further verify the role of SGK1 in low Cl- environment-induced proliferation. The results revealed that overexpression of ClC-3 further enhanced hypotonic solution-induced cell viability, cell cycle transition, and CREB activation, which were alleviated or potentiated by silencing or overexpression of SGK1. In summary, this study provides compelling evidences that SGK1, as a Cl--sensitive kinase, is a critical link between low osmotic pressure and proliferation in BASMCs, and shed a new light on the treatment of proliferation-associated cardiovascular diseases.

Vascular smooth muscle cell (VSMC) migration plays a critical role in the pathogenesis of many cardiovascular diseases. We recently showed that TMEM16A is involved in hypertensioninduced cerebrovascular remodeling. However, it is unclear whether this effect is related to the regulation of VSMC migration. Here, we investigated whether and how TMEM16A contributes to migration in basilar artery smooth muscle cells (BASMCs). We observed that AngII increased the migration of cultured BASMCs, which was markedly inhibited by overexpression of TMEM16A. TMEM16A overexpression inhibited AngII-induced RhoA/ROCK2 activation, and myosin light chain phosphatase (MLCP) and myosin light chain (MLC20) phosphorylation. But AngII-induced myosin light chain kinase (MLCK) activation was not affected by TMEM16A. Furthermore, a suppressed activation of integrin beta 3/FAK pathway, determined by reduced integrinb3 expression, FAK phosphorylation and F-actin rearrangement, was observed in TMEM16A-overexpressing BASMCs upon AngII stimulation. Contrary to the results of TMEM16A overexpression, silencing of TMEM16A showed the opposite effects. These in vitro results were further demonstrated in vivo in basilar arteries from VSMC-specific TMEM16A transgenic mice during AngII-induced hypertension. Moreover, we observed that the inhibitory effect of TMEM16A on BASMC migration was mediated by decreasing the activation of WNK1, a Cl- -sensitive serine/threonine kinase. In conclusion, this study demonstrated that TMEM16A suppressed AngII-induced BASMC migration, thus contributing to the protection against cerebrovascular remodeling during AngII-infused hypertension. TMEM16A may exert this effect by suppressing the RhoA/ROCK2/MLCP/MLC20 and integrinb3/FAK signaling pathways via inhibiting WNK1. Our results suggest that TMEM16A may serve as a novel therapeutic target for VSMC migration-related diseases, such as vascular remodeling. (C) 2021 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.

Rationale: Transmembrane member 16A (TMEM16A) is a component of calcium-activated chloride channels that regulate vascular smooth muscle cell (SMC) proliferation and remodeling. Autophagy, a highly conserved cellular catabolic process in eukaryotes, exerts important physiological functions in vascular SMCs. In the current study, we investigated the relationship between TMEM16A and autophagy during vascular remodeling. Methods: We generated a transgenic mouse that overexpresses TMEM16A specifically in vascular SMCs to verify the role of TMEM16A in vascular remodeling. Techniques employed included immunofluorescence, electron microscopy, co-immunoprecipitation, and Western blotting. Results: Autophagy was activated in aortas from angiotensin II (AngII)-induced hypertensive mice with decreased TMEM16A expression. The numbers of light chain 3B (LC3B)-positive puncta in aortas correlated with the medial cross-sectional aorta areas and TMEM16A expression during hypertension. SMC-specific TMEM16A overexpression markedly inhibited AngII-induced autophagy in mouse aortas. Moreover, in mouse aortic SMCs (MASMCs), AngII-induced autophagosome formation and autophagic flux were blocked by TMEM16A upregulation and were promoted by TMEM16A knockdown. The effect of TMEM16A on autophagy was independent of the mTOR pathway, but was associated with reduced kinase activity of the vacuolar protein sorting 34 (VPS34) enzyme. Overexpression of VPS34 attenuated the effect of TMEM16A overexpression on MASMC proliferation, while the effect of TMEM16A downregulation was abrogated by a VPS34 inhibitor. Further, co-immunoprecipitation assays revealed that TMEM16A interacts with p62. TMEM16A overexpression inhibited AngII-induced p62-Bcl-2 binding and enhanced Bcl-2-Beclin-1 interactions, leading to suppression of Beclin-1/VPS34 complex formation. However, TMEM16A downregulation showed the opposite effects. Conclusion: TMEM16A regulates the four-way interaction between p62, Bcl-2, Beclin-1, and VPS34, and coordinately prevents vascular autophagy and remodeling.

Serum- and glucocorticoid-inducible kinease-1 (SGK1) is a serine/threonine kinase regulated by hypotonic stimuli, which is involved in regulation of cell cycle and apoptosis. Our previous study shows that activation of volume-regulated Cl − channels (VRCCs) protects rat basilar artery smooth muscle cells (BASMCs) against hydrogen peroxide (H 2 O 2 )-induced apoptosis. In the present study, we investigated whether SGK1 was involved in the protective effect of VRCCs in BASMCs. We showed that hypotonic challenge significantly reduced H 2 O 2 -induced apoptosis, and increased SGK1 phosphorylation, but did not affect SGK1 protein expression. The protective effect of hypotonic challenge against H 2 O 2 -induced apoptosis was mediated through inhibiting mitochondria-dependent apoptotic pathway, evidenced by increased Bcl-2/Bax ratio, stabilizing mitochondrial membrane potential (MMP), decreased cytochrome c release from the mitochondria to the cytoplasm, and inhibition of the activation of caspase-9 and caspase-3. These protective effects of hypotonic challenge against H 2 O 2 -induced apoptosis was diminished and enhanced, respectively, by SGK1 knockdown and overexpression. We further revealed that SGK1 activation significantly increased forkhead box O3a (FOXO3a) phosphorylation, and then inhibited the translocation of FOXO3a into nucleus and the subsequent expression of Bcl-2 interacting mediator of cell death (Bim). In conclusion, SGK1 mediates the protective effect of VRCCs against H 2 O 2 -induced apoptosis in BASMCs via inhibiting FOXO3a/Bim signaling pathway. Our results provide compelling evidences that SGK1 is a critical link between VRCCs and apoptosis, and shed a new light on the treatment of vascular apoptosis-associated diseases, such as vascular remodeling, angiogenesis, and atherosclerosis.

Transient Receptor Potential Melastatin-2 (TRPM2) is a nonselective cation channel mediating Ca2+ influx in response to oxidative stress. Given that insulin resistance-related endothelial dysfunction in obesity attributes to fatty-acid-induced reactive oxygen species (ROS) overproduction, in this study, we addressed the possible role of TRPM2 in obesity-related endothelial insulin resistance and the underlying mechanisms. Whole-cell patch clamp technique, intracellular Ca2+ concentration measurement, western blot, vasorelaxation assay, and high-fat diet (HFD)-induced obese model were employed to assess the relationship between TRPM2 and endothelial insulin response. We found that both the expression and activity of TRPM2 were higher in endothelial cells of obese mice. Palmitate rose a cationic current in endothelial cells which was inhibited or enlarged by TRPM2 knockdown or overexpression. Silencing of TRPM2 remarkably improved insulin-induced endothelial Akt activation, nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production, while TRPM2 overexpression resulted in the opposite effects. Furthermore, TRPM2-mediated Ca2+ entry, CaMKII activation and the following activation of PERK/ATF4/TRB3 cascade were involved in the mechanism of obesity or palmitate-induced endothelial insulin resistance. Notably, in vivo study, knockdown of TRPM2 with adeno-associated virus harboring short-hairpin RNA (shRNA) against TRPM2 alleviated endothelial insulin resistance and ameliorated endothelium-dependent vasodilatation in obese mice. Thus, these results suggest that TRPM2-activated Ca2+ signaling is necessary to induce insulin resistance-related endothelial dysfunction in obesity. Downregulation or pharmacological inhibition of TRPM2 channels may lead to the development of effective drugs for treatment of endothelial dysfunction associated with oxidative stress state.