Nox2 contributes to hyperinsulinemia-induced redox imbalance and impaired vascular function

Light and Shadow of Na-Glucose Cotransporter 2 Inhibitors in the Treatment of Diabetes Mellitus: Points for Improvement Based on Our Clinical Experience

We analyzed the effect of Na-glucose cotransporter 2 inhibitors (SGLT2-I) in diabetic patients visiting our hospital. The study included 236 patients treated with SGLT2-I alone or with codiabetic drugs for at least two years. We analyzed overtime changes in glycosylated hemoglobin A1c (HbA1c) in the patients by repeated analyses of variance (ANOVA) and evaluated the therapeutic effect. HbA1c levels decreased significantly in the first six months after treatment. Afterward, they leveled off and increased slightly over the next two years. Six months after treatment, the mean (SD) of HbA1c was 8.19 (1.46) %; the mean difference dropped by 0.91%, and HbA1c in mild DM2 did not drop by below 8.0%. Overall, there was only a slight improvement. We performed multivariate logistic regression analysis using a model with or without improvement as the objective variable and several explanatory variables. Na and Hct were significant factors. They increased considerably over six months and then leveled off. eGFR significantly reduced in the hyperfiltration group six months after treatment. The annual decline rate in eGFR was also faster, even in the nonhyperfiltration group than in the healthy subjects, which may be a characteristic of renal clearance in SGLT2-I treatment. In conclusion, SGLT2-I is an excellent antidiabetic, nephroprotective agent to eliminate hyperfiltration, but unfortunately, SGLT2-I alone does not have enough power to reduce blood glucose levels. SGLT2-I, with insulin or insulin secretagogues, enhances insulin resistance, induces hyperinsulinemia, and exacerbates type 2 DM. In contrast, SGLT2-I, with noninsulin antidiabetic agents and a low-carbohydrate diet, may bring better results.

Adiposomes from Obese-Diabetic Individuals Promote Endothelial Dysfunction and Loss of Surface Caveolae

Glycosphingolipids (GSLs) are products of lipid glycosylation that have been implicated in the development of cardiovascular diseases. In diabetes, the adipocyte microenvironment is characterized by hyperglycemia and inflammation, resulting in high levels of GSLs. Therefore, we sought to assess the GSL content in extracellular vesicles derived from the adipose tissues (adiposomes) of obese-diabetic (OB-T2D) subjects and their impact on endothelial cell function. To this end, endothelial cells were exposed to adiposomes isolated from OB-T2D versus healthy subjects. Cells were assessed for caveolar integrity and related signaling, such as Src-kinase and caveolin-1 (cav-1) phosphorylation, and functional pathways, such as endothelial nitric oxide synthase (eNOS) activity. Compared with adiposomes from healthy subjects, OB-T2D adiposomes had higher levels of GSLs, especially LacCer and GM3; they promoted cav-1 phosphorylation coupled to an obvious loss of endothelial surface caveolae and induced eNOS-uncoupling, peroxynitrite generation, and cav-1 nitrosylation. These effects were abolished by Src kinase inhibition and were not observed in GSL-depleted adiposomes. At the functional levels, OB-T2D adiposomes reduced nitric oxide production, shear response, and albumin intake in endothelial cells and impaired flow-induced dilation in healthy arterioles. In conclusion, OB-T2D adiposomes carried a detrimental GSL cargo that disturbed endothelial caveolae and the associated signaling.

Feeding enhances fibronectin adherence of quiescent lymphocytes through non-canonical insulin signalling

Nutritional availability during fasting and refeeding affects the temporal redistribution of lymphoid and myeloid immune cells among the circulating and tissue-resident pools. Conversely, nutritional imbalance and impaired glucose metabolism are associated with chronic inflammation, aberrant immunity and anomalous leukocyte trafficking. Despite being exposed to periodic alterations in blood insulin levels upon fasting and feeding, studies exploring the physiological effects of these hormonal changes on quiescent immune cell function and trafficking are scanty. Here, we report that oral glucose load in mice and healthy men enhances the adherence of circulating peripheral blood mononuclear cells (PBMCs) and lymphocytes to fibronectin. Adherence to fibronectin is also observed upon regular intake of breakfast following overnight fasting in healthy subjects. This glucose load-induced phenomenon is abrogated in streptozotocin-injected mice that lack insulin. Intra-vital microscopy in mice demonstrated that oral glucose feeding enhances the homing of PBMCs to injured blood vessels in vivo. Furthermore, employing flow cytometry, Western blotting and adhesion assays for PBMCs and Jurkat-T cells, we elucidate that insulin enhances fibronectin adherence of quiescent lymphocytes through non-canonical signalling involving insulin-like growth factor-1 receptor (IGF-1R) autophosphorylation, phospholipase C gamma-1 (PLCγ-1) Tyr783 phosphorylation and inside-out activation of β-integrins respectively. Our findings uncover the physiological relevance of post-prandial insulin spikes in regulating the adherence and trafficking of circulating quiescent T-cells through fibronectin-integrin interaction.

Cross-Talk of NADPH Oxidases and Inflammation in Obesity

Obesity is a major risk factor for cardiovascular and metabolic diseases. Multiple experimental and clinical studies have shown increased oxidative stress and inflammation linked to obesity. NADPH oxidases are major sources of reactive oxygen species in the cardiovascular system and in metabolically active cells and organs. An impaired balance due to the increased formation of reactive oxygen species and a reduced antioxidative capacity contributes to the pathophysiology of cardiovascular and metabolic diseases and is linked to inflammation as a major pathomechanism in cardiometabolic diseases. Non-alcoholic fatty liver disease is particularly characterized by increased oxidative stress and inflammation. In recent years, COVID-19 infections have also increased oxidative stress and inflammation in infected cells and tissues. Increasing evidence supports the idea of an increased risk for severe clinical complications of cardiometabolic diseases after COVID-19. In this review, we discuss the role of oxidative stress and inflammation in experimental models and clinical studies of obesity, cardiovascular diseases, COVID-19 infections and potential therapeutic strategies.

Structure, Activation, and Regulation of NOX2: At the Crossroad between the Innate Immunity and Oxidative Stress-Mediated Pathologies

Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) is a multisubunit enzyme complex that participates in the generation of superoxide or hydrogen peroxide (H₂O₂) and plays a key role in several biological functions. Among seven known NOX isoforms, NOX2 was the first identified in phagocytes but is also expressed in several other cell types including endothelial cells, platelets, microglia, neurons, and muscle cells. NOX2 has been assigned multiple roles in regulating many aspects of innate and adaptive immunity, and human and mouse models of NOX2 genetic deletion highlighted this key role. On the other side, NOX2 hyperactivation is involved in the pathogenesis of several diseases with different etiologies but all are characterized by an increase in oxidative stress and inflammatory process. From this point of view, the modulation of NOX2 represents an important therapeutic strategy aimed at reducing the damage associated with its hyperactivation. Although pharmacological strategies to selectively modulate NOX2 are implemented thanks to new biotechnologies, this field of research remains to be explored. Therefore, in this review, we analyzed the role of NOX2 at the crossroads between immunity and pathologies mediated by its hyperactivation. We described (1) the mechanisms of activation and regulation, (2) human, mouse, and cellular models studied to understand the role of NOX2 as an enzyme of innate immunity, (3) some of the pathologies associated with its hyperactivation, and (4) the inhibitory strategies, with reference to the most recent discoveries.

CircUCK2 regulates HECTD1-mediated endothelial-mesenchymal transition inhibition by interacting with FUS and protects the blood-brain barrier in ischemic stroke

Ischemic stroke (IS) has become a cerebrovascular disease of widespread concern. Overexpression of circUCK2 alleviates neuronal damage in IS. However, the specific regulatory mechanisms of circUCK2 are not fully understood. In this study, we found that circUCK2 and HECT domain E3 ubiquitin ligase 1 (HECTD1) were downregulated in IS models in vitro and in vivo. Overexpression of circUCK2 or HECTD1 inhibited endothelial-mesenchymal transition (EndoMT) and protected the blood-brain barrier (BBB) in transient middle cerebral artery occlusion mice from damage. It was further discovered that circUCK2 regulated HECTD1 expressions by interacting with fused in sarcoma (FUS). Moreover, FUS overexpression partially restored the effect of circUCK2 on EndoMT, and overexpression of HECTD1 weakened the effect of FUS on EndoMT. Collectively, circUCK2 upregulates the expression of HECTD1 by combining with FUS and inhibits EndoMT to alleviate BBB damage in IS both in vivo and in vitro.

Endothelial NOX4 aggravates eNOS uncoupling by decreasing dihydrofolate reductase after subarachnoid hemorrhage

Endothelial malfunction is a major contributor to early or delayed vasospasm after subarachnoid hemorrhage (SAH). As a representative form of endothelial dysfunction, endothelial nitric oxide synthase (eNOS) uncoupling leads to a reduction in nitric oxide (NO) generated by endothelial cells. In this study, we investigated how the interaction between endothelial NOX4 (nicotinamide adenine dinucleotide phosphate oxidase 4) and DHFR (dihydrofolate reductase) contributes to eNOS uncoupling after SAH. Setanaxib and the adeno-associated virus (AAV) targeting brain vascular endothelia were injected through the tail vein and the expression and localization of proteins were examined by western blot and immunofluorescence staining. The NO content was measured using the NO assay kit, and laser speckle contrast imaging was used to assess cortical perfusion. ROS (reactive oxygen species) level was detected by DHE (dihydroethidium) staining, DCFH-DA (2',7'-dichlorofluorescin diacetate) staining and H₂O₂ (hydrogen peroxide) measurement. The Garcia score was employed to examine neurological function. Setanaxib is widely used for its preferential inhibition for NOX1/4 over other NOX isoforms. After endothelial NOX4 was inhibited by Setanaxib in a mouse model of SAH, the endothelial DHFR level was significantly elevated, which attenuated eNOS uncoupling, increased cortical perfusion, and improved the neurological function. The protective role of inhibiting endothelial NOX4, however, disappeared after knocking down endothelial DHFR. Our results suggest that endothelial DHFR decreased significantly because of the elevated level of endothelial NOX4, which aggravated eNOS uncoupling after SAH, leading to decreased cortical perfusion and worse neurological outcome.

Insulin antibody as a biomarker to monitor the development of type 2 diabetes in county hospitals in China

Background

The significance of insulin antibody (IA) detection in type 2 diabetes mellitus (T2DM) has received scant attention from county hospitals in China. We aimed to introduce exogenous IA positive rate and its relative factors in T2DM treated with insulin in Xiangshan County of Ningbo City, analyzing the immunogenicity of different kinds of insulin.

Methods

Patients who were residents from the Danxi community and six towns (Dongchen, Xizhou, Maoyang, Sizhoutou, Juexi, and Qiangtou) in Xiangshan County and diagnosed with T2DM and treated with insulins at Xiangshan Hospital of TCM Medical and Health Group between August 2019 and June 2020 were identified. Those who met the eligibility criteria were included and assigned to the IA-positive or IA-negative group. The immunogenicity of different insulins was compared between the two groups.

Results

Among 992 patients, 781 were eligible for IA detection, and 40.2% of them were IA positive. Blood IA was closely associated with fasting and 2-h glucose, insulin, and C peptide levels and higher insulin dosage. Patients receiving basal insulin treatment showed significantly lower blood IA than those treated with mixed human insulin, premixed human insulins, rapid-acting analogs, or a combination of basal and rapid-acting analogs.

Ginsenoside Rd ameliorates high glucose-induced retinal endothelial injury through AMPK-STRT1 interdependence

Diabetic retinopathy (DR) manifests as a complicated and blinding complication in diabetes mellitus. First-line treatments for advanced DR have shown ocular side-effects in some patients. Ginsenoside Rd (Rd), an active ingredient isolated from Panax notoginseng and P. ginseng, has demonstrated diverse and powerful activities on neuroprotection, anticancer and anti-inflammation, but its vascular protective effects have rarely been reported. Herein, this study aims to investigate the protective effects of Rd on retinal endothelial injury with emphasis on AMPK/SIRT1 interaction. The results indicated that Rd promoted AMPK activation and SIRT1 expression. Besides, Rd strengthened the interaction between AMPK and SIRT1 by increasing NAD⁺/NADH levels and LKB1 deacetylation in endothelial cells. Moreover, Rd reversed high glucose-induced activation of NOX2, oxidative stress, mitochondrial dysfunction, and endothelial apoptosis in an AMPK/SIRT1-interdependent manner. Hyperglycemia induced loss of endothelial cells and other retinal damage, which was restored by Rd via activating AMPK and SIRT1 in vivo. The enhancement of AMPK/SIRT1 interaction by Rd beneficially modulated oxidative stress and apoptosis, and ameliorated diabetes-driven vascular damage. These data also supported the evidence for Rd clinical development of pharmacological interventions and provided a novel potential vascular protective drug for early DR.

Skeletal Muscle Microvascular Dysfunction in Obesity-Related Insulin Resistance: Pathophysiological Mechanisms and Therapeutic Perspectives

Obesity is a worrisomely escalating public health problem globally and one of the leading causes of morbidity and mortality from noncommunicable disease. The epidemiological link between obesity and a broad spectrum of cardiometabolic disorders has been well documented; however, the underlying pathophysiological mechanisms are only partially understood, and effective treatment options remain scarce. Given its critical role in glucose metabolism, skeletal muscle has increasingly become a focus of attention in understanding the mechanisms of impaired insulin function in obesity and the associated metabolic sequelae. We examined the current evidence on the relationship between microvascular dysfunction and insulin resistance in obesity. A growing body of evidence suggest an intimate and reciprocal relationship between skeletal muscle microvascular and glucometabolic physiology. The obesity phenotype is characterized by structural and functional changes in the skeletal muscle microcirculation which contribute to insulin dysfunction and disturbed glucose homeostasis. Several interconnected etiologic molecular mechanisms have been suggested, including endothelial dysfunction by several factors, extracellular matrix remodelling, and induction of oxidative stress and the immunoinflammatory phenotype. We further correlated currently available pharmacological agents that have deductive therapeutic relevance to the explored pathophysiological mechanisms, highlighting a potential clinical perspective in obesity treatment.

Redox Imbalance and Methylation Disturbances in Early Childhood Obesity

Obesity is increasing worldwide in prepubertal children, reducing the age of onset of associated comorbidities, including type 2 diabetes. Sulfur-containing amino acids, methionine, cysteine, and their derivatives play important roles in the transmethylation and transsulfuration pathways. Dysregulation of these pathways leads to alterations in the cellular methylation patterns and an imbalanced redox state. Therefore, we tested the hypothesis that one-carbon metabolism is already dysregulated in prepubertal children with obesity. Peripheral blood was collected from 64 children, and the plasma metabolites from transmethylation and transsulfuration pathways were quantified by HPLC. The cohort was stratified by BMI z-scores and HOMA-IR indices into healthy lean (HL), healthy obese (HO), and unhealthy obese (UHO). Fasting insulin levels were higher in the HO group compared to the HL, while the UHO had the highest. All groups presented normal fasting glycemia. Furthermore, high-density lipoprotein (HDL) was lower while triglycerides and lactate levels were higher in the UHO compared to HO subjects. S-adenosylhomocysteine (SAH) and total homocysteine levels were increased in the HO group compared to HL. Additionally, glutathione metabolism was also altered. Free cystine and oxidized glutathione (GSSG) were increased in the HO as compared to HL subjects. Importantly, the adipocyte secretory function was already compromised at this young age. Elevated circulating leptin and decreased adiponectin levels were observed in the UHO as compared to the HO subjects. Some of these alterations were concomitant with alterations in the DNA methylation patterns in the obese group, independent of the impaired insulin levels. In conclusion, our study informs on novel and important metabolic alterations in the transmethylation and the transsulfuration pathways in the early stages of obesity. Moreover, the altered secretory function of the adipocyte very early in life may be relevant in identifying early metabolic markers of disease that may inform on the increased risk for specific future comorbidities in this population.

INERTIA: A pilot study of the impact of progressive resistance training on blood pressure control in older adults with sarcopenia

Sarcopenia, and high blood pressure are highly prevalent, preventable conditions that pose significant burden for older adults and on the healthcare system. Current prevention and treatment of high blood pressure in sarcopenia, by non-pharmacological approaches remain limited and are far from optimal. Clinical trials and mechanistic studies provide encouraging evidence of a plausible therapeutic effect of progressive resistance training (PRT) on blood pressure in younger, and pre-hypertensive and hypertensive older adults. The impact of PRT on blood pressure has not been empirically tested in older adults with sarcopenia. This pilot study aims to provide effect size confidence intervals, clinical trial and intervention feasibility data, and procedural materials for a full-scale randomized controlled trial that will determine the efficacy of PRT intervention as a therapeutic strategy for blood pressure control in older adults with sarcopenia. Participants (N = 90) will be randomized to receive exercise educational materials or the PRT intervention consisting of 24 supervised exercise sessions over 12-weeks. Follow-up assessments will occur at 12-weeks and one-year later. The primary outcome is systolic blood pressure and diastolic blood pressure, analyzed separately. Microvascular mechanisms linking muscle (perfusion, strength, function) to changes in blood pressure will be explored at baseline and 12-weeks. This study will provide new evidence for the therapeutic effect of PRT as a non-pharmacological strategy for improving blood pressure. Insights gained may also inform of the potential role of muscle strength as a novel target for blood pressure control, and future exercise prescription guidelines related to muscle strengthening in high-risk older adults.

Apolipoprotein A-I mimetic peptide inhibits atherosclerosis by increasing tetrahydrobiopterin via regulation of GTP-cyclohydrolase 1 and reducing uncoupled endothelial nitric oxide synthase activity

BACKGROUND AND AIMS

The apolipoprotein A-I mimetic peptide D-4F, among its anti-atherosclerotic effects, improves vasodilation through mechanisms not fully elucidated yet.

METHODS

Low-density lipoprotein (LDL) receptor null (LDLr-/-) mice were fed Western diet with or without D-4F. We then measured atherosclerotic lesion formation, endothelial nitric oxide synthase (eNOS) phosphorylation and its association with heat shock protein 90 (HSP90), nitric oxide (NO) and superoxide anion (O2•-) production, and tetrahydrobiopterin (BH4) and GTP-cyclohydrolase 1 (GCH-1) concentration in the aorta. Human umbilical vein endothelial cells (HUVECs) and aortas were treated with oxidized LDL (oxLDL) with or without D-4F; subsequently, BH4 and GCH-1 concentration, NO and O2•- production, eNOS association with HSP90, and endothelium-dependent vasodilation were measured.

RESULTS

Unexpectedly, eNOS phosphorylation, eNOS-HSP90 association, and O2•- production were increased, whereas BH4 and GCH-1 concentration and NO production were reduced in atherosclerosis. D-4F significantly inhibited atherosclerosis, eNOS phosphorylation, eNOS-HSP90 association, and O2•- generation but increased NO production and BH4 and GCH-1 concentration. OxLDL reduced NO production and BH4 and GCH-1 concentration but enhanced O2•- generation and eNOS association with HSP90, and impaired endothelium-dependent vasodilation. D-4F inhibited the overall effects of oxLDL.

CONCLUSIONS

Hypercholesterolemia enhanced uncoupled eNOS activity by decreasing GCH-1 concentration, thereby reducing BH4 levels. D-4F reduced uncoupled eNOS activity by increasing BH4 levels through GCH-1 expression and decreasing eNOS phosphorylation and eNOS-HSP90 association. Our findings elucidate a novel mechanism by which hypercholesterolemia induces atherosclerosis and D-4F inhibits it, providing a potential therapeutic approach.

Therapeutic potential of targeting oxidative stress in diabetic cardiomyopathy

Even in the absence of coronary artery disease and hypertension, diabetes mellitus (DM) may increase the risk for heart failure development. This risk evolves from functional and structural alterations induced by diabetes in the heart, a cardiac entity termed diabetic cardiomyopathy (DbCM). Oxidative stress, defined as the imbalance of reactive oxygen species (ROS) has been increasingly proposed to contribute to the development of DbCM. There are several sources of ROS production including the mitochondria, NAD(P)H oxidase, xanthine oxidase, and uncoupled nitric oxide synthase. Overproduction of ROS in DbCM is thought to be counterbalanced by elevated antioxidant defense enzymes such as catalase and superoxide dismutase. Excess ROS in the cardiomyocyte results in further ROS production, mitochondrial DNA damage, lipid peroxidation, post-translational modifications of proteins and ultimately cell death and cardiac dysfunction. Furthermore, ROS modulates transcription factors responsible for expression of antioxidant enzymes. Lastly, evidence exists that several pharmacological agents may convey cardiovascular benefit by antioxidant mechanisms. As such, increasing our understanding of the pathways that lead to increased ROS production and impaired antioxidant defense may enable the development of therapeutic strategies against the progression of DbCM. Herein, we review the current knowledge about causes and consequences of ROS in DbCM, as well as the therapeutic potential and strategies of targeting oxidative stress in the diabetic heart.

Impact of Hyperinsulinemia on Long-Term Clinical Outcomes of Percutaneous Coronary Intervention in Patients without Diabetes Who Have Acute Myocardial Syndrome

BACKGROUND AND OBJECTIVES

Hyperinsulinemia plays a key role in the development of cardiovascular impairment in patients with metabolic syndrome. The aim of this study was to evaluate the influence of hyperinsulinemia on long-term clinical outcomes of percutaneous coronary intervention (PCI) in patients without diabetes mellitus who have acute myocardial syndrome (ACS).

METHODS

Between March 2016 and January 2019, we enrolled 468 patients with ACS and without diabetes mellitus who received primary PCI. Patients were divided into a low-insulin group (n = 157), medium-insulin group (n = 154), and high-insulin group (n = 157) according to tertiles of fasting insulin level. The primary endpoint was major adverse cardiac events (MACE; all-cause death, non-fatal myocardial infarction, target vessel revascularization [TVR]) at 24 months. The secondary endpoint was angina hospitalization.

RESULTS

Patients in the high-insulin group had an unfavorable prognosis, with a higher rate of MACE (34.39%) than the low-insulin group (22.29%) and medium-insulin group (23.37%) at 24 months (P < 0.05). This difference was mainly driven by the increase in TVR. The high-insulin group also had a higher rate of angina hospitalization than the low-insulin group. Cox proportional hazards regression showed that high-insulin level (hazard ratio [HR] 1.870, 95% confidence interval [CI] 1.202-2.909), small-vessel lesion (HR 1.713, 95% CI 1.111-2.642), bifurcation lesion (HR 3.394, 95% CI 2.033-5.067), SYNTAX score (HR 1.084, 95% CI 1.039-1.130), and stent length (HR 1.017, 95% CI 1.002-1.032) increased the incidence of MACE in patients with ACS and without diabetes who underwent PCI.

CONCLUSION

Hyperinsulinemia might be a valid predictor of clinical outcomes in patients with ACS undergoing PCI.

Malic enzyme 1 (ME1) in the biology of cancer: it is not just intermediary metabolism

Malic enzyme 1 (ME1) is a cytosolic protein that catalyzes the conversion of malate to pyruvate while concomitantly generating NADPH from NADP. Early studies identified ME1 as a mediator of intermediary metabolism primarily through its participatory roles in lipid and cholesterol biosynthesis. ME1 was one of the first identified insulin-regulated genes in liver and adipose and is a transcriptional target of thyroxine. Multiple studies have since documented that ME1 is pro-oncogenic in numerous epithelial cancers. In tumor cells, the reduction of ME1 gene expression or the inhibition of its activity resulted in decreases in proliferation, epithelial-to-mesenchymal transition and in vitro migration, and conversely, in promotion of oxidative stress, apoptosis and/or cellular senescence. Here, we integrate recent findings to highlight ME1's role in oncogenesis, provide a rationale for its nexus with metabolic syndrome and diabetes, and raise the prospects of targeting the cytosolic NADPH network to improve therapeutic approaches against multiple cancers.

Urban particulate matter disturbs the equilibrium of mitochondrial dynamics and biogenesis in human vascular endothelial cells

Since ambient particulate matter (APM) is closely related to cardiovascular damage with mitochondria being its potential targets, this study was designed to explore the impact of APM on mitochondrial homeostasis, especially on mitochondrial dynamics and biogenesis in human vascular endothelial cells, using a kind of standard material, PM SRM1648a. As a result, internalized particles lead to mitochondrial dysfunction in EA.hy926 human endothelial cells, including mitochondrial reactive oxygen species (mtROS) overproduction, mitochondrial membrane potential (MMP) reduction and adenosine triphosphate (ATP) inhibition, coupled with additional release of mitochondrial DNA (mtDNA) into the cytosol. Moreover, morphological and structural changes in mitochondria are observed in response to PM SRM1648a. In that aspect, according to the evidence of shorter fragmented mitochondria dispersed throughout the cytoplasm, along with aberrant upregulation of fission-related mRNAs/proteins, the mitochondria exhibit a fission phenotype shifting from intact reticular network to fragmentized punctate shapes. Mechanistically, PM SRM1648a facilitates phosphorylation of DRP1 at Ser616 in HUVECs, and triggers its dephosphorylation at Ser637 residue in both EA.hy926 and HUVECs, which are supportive events for mitochondrial fission during particle exposure. Additionally, suppression of a master energy modulator, PGC-1α, reveals that PM SRM1648a has the ability to impair mitochondrial biogenesis. Collectively, it could be well concluded that PM SRM1648a interferes with the equilibrium of mitochondrial dynamics and biogenesis, which is likely to play a pivotal role in mitochondrial dysfunction driven by particles, eventually contributing to endothelial cell damage. Of note, it is more reasonable to conduct risk assessment from both cellular level and subcellular structures, among which mitochondria-targeted toxicity supplements more comprehensive understanding of APM inducible vascular toxicity.

Assessment of intima-media thickness of the carotid artery and intraluminal diameter of the brachial artery as cardiovascular risk markers in Brazilian adolescents with overweight or obesity

Background The intima-media thickness of the carotid artery (cIMT) and endothelial dysfunction are associated with cardiovascular (CV) disease. Objectives To evaluate the correlation between cIMT, brachial intraluminal diameter and flow-mediated vasodilation on the reactive hyperemia phase in adolescents with obesity with predictors of CV risk. Methods Seventy-three pubertal patients with overweight or obesity were evaluated (45 girls) with a mean (standard deviation [SD]) age of 12.9 (2.5) years. Patients underwent anthropometric measurements and had the lipid profile, oral glucose tolerance test (oGTT) and serum intercellular adhesion molecule-1 (sICAM-1) levels analyzed. The ratios of the waist circumference (WC)/height (WHtR) and triglycerides (TG)/high-density lipoprotein cholesterol (HDL-C), homeostatic model assessment of insulin resistance (HOMA-IR), the Matsuda index and insulin area under the curve (AUC) were calculated. All patients were evaluated for cIMT and arterial blood flow velocity of the brachial artery. Results 75.3% of the patients had high cIMT values. We found a positive correlation between WHtR and cIMT (r = 0.233; p = 0.050). There was a positive correlation between sICAM-1 and insulin AUC (r = 0.323; p = 0.012) and WHtR (r = 0.258; p = 0.047). Patients with abnormal arterial dilation had higher sICAM-1 values (p = 0.02) despite having smaller WHtR (p = 0.046). Conclusions These adolescents with obesity had high cIMT values. Insulin resistance was associated with sICAM-1. Endothelial dysfunction was positively correlated with sICAM-1. There is no consensus about what the best laboratorial approach to evaluate insulin resistance in adolescents is, and the cutoff values of each method are arbitrary. So, as we saw earlier, the association between anthropometric data (WHtR) and ultrasound findings could be useful to evaluate the CV risk of these adolescents with obesity, because of its practical, direct and low-cost value.

The contribution of chymase-dependent formation of ANG II to cardiac dysfunction in metabolic syndrome of young rats: roles of fructose and EETs

The roles of ACE-independent ANG II production via chymase and therapeutic potential of epoxyeicosatrienoic acids (EETs) in fructose-induced metabolic syndrome (MetS) in the adolescent population remain elusive. Thus we tested the hypothesis that a high-fructose diet (HFD) in young rats elicits chymase-dependent increases in ANG II production and oxidative stress, responses that are reversible by 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU), an inhibitor of soluble epoxide hydrolase (sEH) that metabolizes EETs. Three groups of weanling rats (21-day-old) were fed a normal diet, 60% HFD, and HFD with TPPU, respectively, for 30 days. HFD rats developed MetS, characterized by hyperglycemia, hyperinsulinemia, and hypertension and associated with decreases in cardiac output and stroke volume and loss of nitric oxide (NO) modulation of myocardial oxygen consumption; all impairments were normalized by TPPU that significantly elevated circulating 11,12-EET, a major cardiac EET isoform. In the presence of comparable cardiac angiotensin-converting enzyme (ACE) expression/activity among the three groups, HFD rats exhibited significantly greater chymase-dependent ANG II formation in hearts, as indicated by an augmented cardiac chymase content as a function of enhanced mast cell degranulation. The enhanced chymase-dependent ANG II production was paralleled with increases in ANG II type 1 receptor (AT₁R) expression and NADPH oxidase (Nox)-induced superoxide, alterations that were significantly reversed by TPPU. Conversely, HFD-induced downregulation of cardiac ACE2, followed by a lower Ang-(1-7) level displayed in an TPPU-irreversible manner. In conclusion, HFD-driven adverse chymase/ANG II/Nox/superoxide signaling in young rats was prevented by inhibition of sEH via, at least in part, an EET-mediated stabilization of mast cells, highlighting chymase and sEH as therapeutic targets during treatment of MetS.NEW & NOTEWORTHY As the highest fructose consumers, the adolescent population is highly susceptible to the metabolic syndrome, where increases in mast cell chymase-dependent formation of ANG II, ensued by cardiometabolic dysfunction, are reversible in response to inhibition of soluble epoxide hydrolase (sEH). This study highlights chymase and sEH as therapeutic targets and unravels novel avenues for the development of optimal strategies for young patients with fructose-induced metabolic syndrome.

Can Medicinal Plants and Bioactive Compounds Combat Lipid Peroxidation Product 4-HNE-Induced Deleterious Effects?

The toxic reactive aldehyde 4-hydroxynonenal (4-HNE) belongs to the advanced lipid peroxidation end products. Accumulation of 4-HNE and formation of 4-HNE adducts induced by redox imbalance participate in several cytotoxic processes, which contribute to the pathogenesis and progression of oxidative stress-related human disorders. Medicinal plants and bioactive natural compounds are suggested to be attractive sources of potential agents to mitigate oxidative stress, but little is known about the therapeutic potentials especially on combating 4-HNE-induced deleterious effects. Of note, some investigations clarify the attenuation of medicinal plants and bioactive compounds on 4-HNE-induced disturbances, but strong evidence is needed that these plants and compounds serve as potent agents in the prevention and treatment of disorders driven by 4-HNE. Therefore, this review highlights the pharmacological basis of these medicinal plants and bioactive compounds to combat 4-HNE-induced deleterious effects in oxidative stress-related disorders, such as neurotoxicity and neurological disorder, eye damage, cardiovascular injury, liver injury, and energy metabolism disorder. In addition, this review briefly discusses with special attention to the strategies for developing potential therapies by future applications of these medicinal plants and bioactive compounds, which will help biological and pharmacological scientists to explore the new vistas of medicinal plants in combating 4-HNE-induced deleterious effects.

Insulin as an immunomodulatory hormone

Insulin plays an indispensable role in the management of hyperglycaemia that arises in a variety of settings, including Type I and II diabetes, gestational diabetes, as well as is in hyperglycaemia following a severe inflammatory insult. However, insulin receptors are also expressed on a range of cells that are not canonically implicated in glucose homeostasis. This includes immune cells, where the anti-inflammatory effects of insulin have been repeatedly reported. However, recent findings have also implicated a more involved role for insulin in shaping the immune response during an infection. This includes the ability of insulin to modulate immune cell differentiation and polarisation as well as the modulation of effector functions such as biocidal ROS production. Finally, inflammatory mediators can through both direct and indirect mechanisms also regulate serum insulin levels, suggesting that insulin may be co-opted by the immune system during an infection to direct immunological operations. Collectively, these observations implicate insulin as a bona fide immune-modulating hormone and suggest that a better understanding of insulin's immunological function may aid in optimising insulin therapy in a range of clinical settings.

Source of Dietary Fat in Pig Diet Affects Adipose Expression of Genes Related to Cancer, Cardiovascular, and Neurodegenerative Diseases

It has been known for many years that excessive consumption of saturated fats has proatherogenic properties, contrary to unsaturated fats. However, the molecular mechanism covering these effects is not fully understood. In this paper, we aimed to identify differentially expressed genes (DEGs) using RNA-sequencing, following feeding pigs with different sources of fat. After comparison of adipose samples from three dietary groups (rapeseed oil (n = 6), beef tallow (n = 5), coconut oil (n = 5)), we identified 29 DEGs (adjusted p-value < 0.05, fold change > 1.3) between beef tallow and rapeseed oil and 2 genes between coconut oil and rapeseed oil groups. No differentially expressed genes were observed between coconut oil and beef tallow groups. Almost all 29 DEGs between rapeseed oil and beef tallow groups are connected to neurodegenerative, cardiovascular diseases, or cancer (e.g., PLAU, CYBB, NCF2, ZNF217, CHAC1, CTCFL). Functional analysis of these genes revealed that they are associated with fluid shear stress response, complement and coagulation cascade, ROS signaling, neurogenesis, and regulation of protein binding and protein catabolic processes. Furthermore, gene set enrichment analysis (GSEA) of the whole datasets from all three comparisons suggests that both beef tallow and coconut oil may trigger changes in the expression level of genes crucial in the pathogenesis of civilization diseases.

NADPH oxidases and oxidase crosstalk in cardiovascular diseases: novel therapeutic targets

Reactive oxygen species (ROS)-dependent production of ROS underlies sustained oxidative stress, which has been implicated in the pathogenesis of cardiovascular diseases such as hypertension, aortic aneurysm, hypercholesterolaemia, atherosclerosis, diabetic vascular complications, cardiac ischaemia-reperfusion injury, myocardial infarction, heart failure and cardiac arrhythmias. Interactions between different oxidases or oxidase systems have been intensively investigated for their roles in inducing sustained oxidative stress. In this Review, we discuss the latest data on the pathobiology of each oxidase component, the complex crosstalk between different oxidase components and the consequences of this crosstalk in mediating cardiovascular disease processes, focusing on the central role of particular NADPH oxidase (NOX) isoforms that are activated in specific cardiovascular diseases. An improved understanding of these mechanisms might facilitate the development of novel therapeutic agents targeting these oxidase systems and their interactions, which could be effective in the prevention and treatment of cardiovascular disorders.

The Role of NADPH Oxidases in the Etiology of Obesity and Metabolic Syndrome: Contribution of Individual Isoforms and Cell Biology

Significance: Highly prevalent in Western cultures, obesity, metabolic syndrome, and diabetes increase the risk of cardiovascular morbidity and mortality and cost health care systems billions of dollars annually. At the cellular level, obesity, metabolic syndrome, and diabetes are associated with increased production of reactive oxygen species (ROS). Increased levels of ROS production in key organ systems such as adipose tissue, skeletal muscle, and the vasculature cause disruption of tissue homeostasis, leading to increased morbidity and risk of mortality. More specifically, growing evidence implicates the nicotinamide adenine dinucleotide phosphate oxidase (NOX) enzymes in these pathologies through impairment of insulin signaling, inflammation, and vascular dysfunction. The NOX family of enzymes is a major driver of redox signaling through its production of superoxide anion, hydrogen peroxide, and attendant downstream metabolites acting on redox-sensitive signaling molecules. Recent Advances: The primary goal of this review is to highlight recent advances and survey our present understanding of cell-specific NOX enzyme contributions to metabolic diseases. Critical Issues: However, due to the short half-lives of individual ROS and/or cellular defense systems, radii of ROS diffusion are commonly short, often restricting redox signaling and oxidant stress to localized events. Thus, special emphasis should be placed on cell type and subcellular location of NOX enzymes to better understand their role in the pathophysiology of metabolic diseases. Future Directions: We discuss the targeting of NOX enzymes as potential therapy and bring to light potential emerging areas of NOX research, microparticles and epigenetics, in the context of metabolic disease.

MiR-92a regulates endothelial progenitor cells (EPCs) by targeting GDF11 via activate SMAD2/3/FAK/Akt/eNOS pathway

Background

The effects of miR-92a on EPCs are still poorly elucidated. This study aimed to investigate the effects of miR-92a on EPCs (Endothelial progenitor cells) in a model of hypoxia (HO) or high glucose (HG)-induced EPCs injury by targeting GDF11 (Differentiation growth factor 11).

Methods

The effects of miR-92a on EPCs subjected to HO or HG were investigated firstly. Subsequently, the action mechanism of miR-92a on EPCs by targeting GDF11 was elucidated. Proliferation, apoptosis, migration, angiogenesis was measured with MTT, flow cytometry, transwell, tube formation respectively. After 24 h, levels of reactive oxygen species (ROS) were measured by fluorescence intensity. LDH and NO (nitric oxide) levels were determined by ELISA. The expression of FLK-1 (fetal liver kinase 1) and vWF (von Willebrand factor) was detected by immunofluorescence. mRNA and protein expression levels were examined using PCR and western blotting respectively. The interaction between miR-92a and GDF11 was evaluated by dual-luciferase reporter assay.

Results

Our results showed that HO or HG increased apoptosis, production of LDH and generation of ROS, but decreased the ability of migration and tube formation and generation of NO in EPCs; inhibiting of miR-92a decreased HO or HG-induced injury of EPCs, whereas miR-92a over-expression had the opposite effect; the protective effects induced by inhibiting of miR-92a on EPCs could be reversed by GDF11 siRNA and the harmful effects induced by over-expression of miR-92a could be rescued by over-expression of GDF11, which showed that the harmful effects of miR-92a be related to its inhibition of GDF11 and subsequent inactivation of the SMAD2/3/FAK/Akt/eNOS signaling pathway.

Conclusions

Inhibiting miR-92a can protect EPCs from HO or HG-induced injury. The effect of miR-92a on EPCs are mediated by regulating of GDF11 and downstream SMAD2/3/FAK/Akt/eNOS signaling pathway.

Differential contribution of Nox1, Nox2 and Nox4 to kidney vascular oxidative stress and endothelial dysfunction in obesity

Oxidative stress-associated endothelial dysfunction is a key pathogenic factor underlying the microvascular complications of metabolic disease. NADPH oxidase (Nox) is a major source of oxidative stress in diabetic nephropathy and chronic kidney disease, despite Nox4 and Nox2 have been identified as relevant sources of vasodilator endothelial H₂O₂.The present study was sought to investigate the role of Nox enzymes in renal vascular oxidative stress and endothelial dysfunction in a rat model of genetic obesity. Endothelial function was assessed in intrarenal arteries of obese Zucker rats (OZR) and their counterparts lean Zucker rats (LZR) mounted in microvascular myographs, and superoxide (O₂^.-) and H₂O₂ production were measured. Impaired endothelium-dependent relaxations to acetylcholine (ACh) were associated to augmented O₂^.- generation, but neither ROS scavengers nor the Nox inhibitor apocynin significantly improved these relaxant responses in renal arteries of OZR. Whereas NO contribution to endothelial relaxations was blunted, catalase-sensitive non-NO non-prostanoid relaxations were enhanced in obese rats. Interestingly, NADPH-dependent O₂^.- production was augmented while NADPH-dependent H₂O₂ generation was reduced, and cytosolic and mitochondrial SOD were up-regulated in kidney of obese rats. Nox4 was down-regulated in renal arteries and Nox4-dependent H₂O₂ generation and endothelial relaxation were reduced in OZR. Up-regulation of both Nox2 and Nox1 was associated with augmented O₂^.- production but reduced H₂O₂ generation and blunted endothelial Nox2-derived H₂O₂-mediated in obese rats. Moreover, increased Nox1-derived O₂^.- contributed to renal endothelial dysfunction in OZR. In summary, the current data support a main role for Nox1-derived O₂^.- in kidney vascular oxidative stress and renal endothelial dysfunction in obesity, while reduced endothelial Nox4 expression associated to decreased H₂O₂ generation and H₂O₂-mediated vasodilatation might hinder Nox4 protective renal effects thus contributing to kidney injury. This suggests that effective therapies to counteract oxidative stress and prevent microvascular complications must identify the specific Nox subunits involved in metabolic disease.

Endothelial Dysfunction: Is There a Hyperglycemia-Induced Imbalance of NOX and NOS?

NADPH oxidases (NOX) are enzyme complexes that have received much attention as key molecules in the development of vascular dysfunction. NOX have the primary function of generating reactive oxygen species (ROS), and are considered the main source of ROS production in endothelial cells. The endothelium is a thin monolayer that lines the inner surface of blood vessels, acting as a secretory organ to maintain homeostasis of blood flow. The enzymatic production of nitric oxide (NO) by endothelial NO synthase (eNOS) is critical in mediating endothelial function, and oxidative stress can cause dysregulation of eNOS and endothelial dysfunction. Insulin is a stimulus for increases in blood flow and endothelium-dependent vasodilation. However, cardiovascular disease and type 2 diabetes are characterized by poor control of the endothelial cell redox environment, with a shift toward overproduction of ROS by NOX. Studies in models of type 2 diabetes demonstrate that aberrant NOX activation contributes to uncoupling of eNOS and endothelial dysfunction. It is well-established that endothelial dysfunction precedes the onset of cardiovascular disease, therefore NOX are important molecular links between type 2 diabetes and vascular complications. The aim of the current review is to describe the normal, healthy physiological mechanisms involved in endothelial function, and highlight the central role of NOX in mediating endothelial dysfunction when glucose homeostasis is impaired.

Hyperinsulinemia impairs functions of circulating endothelial progenitor cells

AIMS

Circulating endothelial progenitor cells (EPCs) play a key role in maintaining endothelial function. Dysfunction of EPCs is associated with the cardiovascular complication of diabetes. The purpose of this study is to investigate the direct effects of hyperinsulinemia on EPCs and the underlying mechanisms.

METHODS

EPCs isolated from healthy adults were cultured with various concentrations of insulin (control group, without insulin; physiological insulin group, 10 nM insulin and hyperinsulinemia group, 100 nM insulin) with or without phosphatidylinositol-3-kinase (PI3-K) inhibitor (LY294002, 5 µM), endothelial nitric oxide synthase (eNOS) inhibitor (L-NG-nitro-arginine methyl ester (L-NAME), 100 µM), sodium nitroprusside (SNP, 25 µM), p38 mitogen-activated protein kinase(MAPK) inhibitor (SB203580, 5 µM) or extracellular signal-regulated kinases (ERK) 1/2 inhibitor (PD98059, 10 µM). Proliferation, tube formation, and apoptosis of EPCs were determined. Expressions of eNOS, PI3-K, protein kinase B (Akt), p38 MAPK, and ERK 1/2 were assessed.

RESULTS

Hyperinsulinemia caused a significant decrease in proliferation and tube formation abilities than control group. Hyperinsulinemia increased apoptosis rate of EPCs than control group. Furthermore, hyperinsulinemia downregulated phosphorylation of eNOS, PI3-K and Akt, and upregulated phosphorylation of p38 MAPK and ERK. SNP could restore impaired tube formation induced by hyperinsulinemia. P38 MAPK inhibitor but not ERK inhibitor could decrease apoptosis induced by hyperinsulinemia.

CONCLUSION

Hyperinsulinemia impaired EPCs' tube formation ability by downregulation of PI-3K/Akt/eNOS pathway. Hyperinsulinemia induced apoptosis of EPCs via upregulation of p38 MAPK.

Low-Fat Diet Designed for Weight Loss But Not Weight Maintenance Improves Nitric Oxide-Dependent Arteriolar Vasodilation in Obese Adults

Obesity is associated with microvascular dysfunction. While low-fat diet improves cardiovascular risk, its contributions on microvascular function, independent of weight loss, is unknown. We tested the hypothesis that nitric oxide (NO)-dependent vasodilation in microvessels is improved by low-fat diets designed for weight loss (LFWL) compared to low-fat weight maintenance (LFWM) diet. Obese adults were randomly assigned to either a LFWL diet (n = 11) or LFWM diet (n = 10) for six weeks. Microvessels were obtained from gluteal subcutaneous fat biopsies before and after the intervention for vascular reactivity measurements to acetylcholine (Ach) and flow, with and without L-NAME or indomethacin. Vascular and serum NO and C-reactive protein (CRP) were also measured. LFWL diet increased flow-induced (FID) and ACh-induced dilation (AChID); an effect that was inhibited by L-NAME. Conversely, LFWM diet did not affect FID or AChID. Indomethacin improved FID and AChID in the baseline and this effect was minimized in response to both diets. Serum NO or CRP did not change in response to either diet. In conclusion, LFWL diet improves microvascular reactivity compared to LFWM diet and increased vascular NO contribution to the improved microvascular dilation. These data suggest that weight reduction on low fat diet is critical for microvascular health.

VAS2870 Inhibits Histamine-Induced Calcium Signaling and vWF Secretion in Human Umbilical Vein Endothelial Cells

In this study, we investigated the effects of NAD(P)H oxidase (NOX) inhibitor VAS2870 (3-benzyl-7-(2-benzoxazolyl)thio-1,2,3-triazolo[4,5-d]pyrimidine) on the histamine-induced elevation of free cytoplasmic calcium concentration ([Ca²⁺]_i) and the secretion of von Willebrand factor (vWF) in human umbilical vein endothelial cells (HUVECs) and on relaxation of rat aorta in response to histamine. At 10 μM concentration, VAS2870 suppressed the [Ca²⁺]_i rise induced by histamine. Inhibition was not competitive, with IC50 3.64 and 3.22 μM at 1 and 100 μM concentrations of histamine, respectively. There was no inhibition of [Ca²⁺]_i elevation by VAS2870 in HUVECs in response to the agonist of type 1 protease-activated receptor SFLLRN. VAS2870 attenuated histamine-induced secretion of vWF and did not inhibit basal secretion. VAS2870 did not change the degree of histamine-induced relaxation of rat aortic rings constricted by norepinephrine. We suggest that NOX inhibitors might be used as a tool for preventing thrombosis induced by histamine release from mast cells without affecting vasorelaxation.

Skeletal muscle performance in metabolic disease: Microvascular or mitochondrial limitation or both?

One of the clearly established health outcomes associated with chronic metabolic diseases (eg, type II diabetes mellitus) is that the ability of skeletal muscle to maintain contractile performance during periods of elevated metabolic demand is compromised as compared to the fatigue-resistance of muscle under normal, healthy conditions. While there has been extensive effort dedicated to determining the major factors that contribute to the compromised performance of skeletal muscle with chronic metabolic disease, the extent to which this poor outcome reflects a dysfunctional state of the microcirculation, where the delivery and distribution of metabolic substrates can be impaired, versus derangements to normal metabolic processes and mitochondrial function, versus a combination of the two, represents an area of considerable unknown. The purpose of this manuscript is to present some of the current concepts for dysfunction to both the microcirculation of skeletal muscle as well as to mitochondrial metabolism under these conditions, such that these diverse issues can be merged into an integrated framework for future investigation. Based on an interpretation of the current literature, it may be hypothesized that the primary site of dysfunction with earlier stages of metabolic disease may lie at the level of the vasculature, rather than at the level of the mitochondria.

Decreased Chromosomal Damage in Lymphocytes of Obese Patients After Bariatric Surgery

The number of bariatric surgeries being performed worldwide has markedly risen. While the improvement in obesity-associated comorbidities after bariatric surgery is well-established, very little is known about its impact on cancer risk. The peripheral lymphocyte micronucleus test is a widely used method for the monitoring of chromosomal damage levels in vivo, and micronucleus frequency positively correlates with cancer risk. Therefore, the aim of this study was to compare the micronucleus frequency before and after bariatric surgery in obese subjects. Peripheral blood mononuclear cells were collected from 45 obese subjects before and at two time-points after bariatric surgery (6 and 12 months) to assess spontaneous micronucleus frequency. Consistent with the increased cancer risk previously shown, bariatric surgery-induced weight loss led to a significant reduction in lymphocyte micronucleus frequency after 12 months. Interestingly, comorbidities such as type 2 diabetes mellitus and metabolic syndrome further seemed to have an impact on the lymphocyte micronucleus frequency. Our findings may indicate a successful reduction of cancer risk in patients following weight loss caused by bariatric surgery.

Argirein alleviates vascular endothelial insulin resistance through suppressing the activation of Nox4-dependent O2- production in diabetic rats

BACKGROUND

Insulin resistance in endothelial cells contributes to the development of cardiovascular disease in type 2 diabetes mellitus (T2DM). Therefore, there are great potential clinical implications in developing pharmacological interventions targeting endothelial insulin resistance. Our previous studies indicated that argirein which was developed by combining rhein with L-arginine by a hydrogen bond, could substantially relieved stress related exacerbation of cardiac failure and alleviated cardiac dysfunction in T2DM, which was associated with suppressing NADPH oxidase activity. However, it is unclear whether argirein treatment attenuates the vascular lesion and dysfunction in T2DM and its underlying mechanisms.

METHODS AND RESULTS

The rat aortic endothelial cells (RAECs) were used to treat with palmitic acid (PA), a most common saturated free fatty acid, which could induce insulin resistance. It was showed that argirein increased glucose uptake and glucose transporter-4 (Glut4) expression and reversed the phosphorylation of IRS-1-ser307 and AKT-ser473, consequently resulting in the increase of the production of eNOS and NO in PA-induced RAECs. We further found that argirein blocked the Nox4-dependent superoxide (O₂^-.) generation, which regulated glucose metabolism in RAECs during PA stimulation. In vitro, argirein increased the release of endothelial NO to relieve the vasodilatory response to acetylcholine and insulin, and restored the expression of Nox4 and pIRS-1-ser307 in the aorta endothelium of high-fat diet (HFD)-fed rats following an injection of streptozocin (STZ).

CONCLUSION

These results suggested that argirein could improve endothelial insulin resistance which was attributed to inhibiting Nox4-dependent redox signaling in RAECs. These studies thus revealed the novel effect of argirein to prevent the vascular complication in T2DM.

Diabetes impairs wound healing by Dnmt1-dependent dysregulation of hematopoietic stem cells differentiation towards macrophages

People with type 2 diabetes mellitus (T2DM) have a 25-fold higher risk of limb loss than non-diabetics due in large part to impaired wound healing. Here, we show that the impaired wound healing phenotype found in T2D mice is recapitulated in lethally irradiated wild type recipients, whose hematopoiesis is reconstituted with hematopoietic stem cells (HSCs) from T2D mice, indicating an HSC-autonomous mechanism. This impaired wound healing phenotype of T2D mice is due to a Nox-2-dependent increase in HSC oxidant stress that decreases microRNA let-7d-3p, which, in turn, directly upregulates Dnmt1, leading to the hypermethylation of Notch1, PU.1, and Klf4. This HSC-autonomous mechanism reduces the number of wound macrophages and skews their polarization towards M1 macrophages. These findings reveal a novel inflammatory mechanism by which a metabolic disorder induces an epigenetic mechanism in HSCs, which predetermines the gene expression of terminally differentiated inflammatory cells that controls their number and function.

Cholinergic anti-inflammatory pathway inhibits neointimal hyperplasia by suppressing inflammation and oxidative stress

Neointimal hyperplasia as a consequence of vascular injury is aggravated by inflammatory reaction and oxidative stress. The α7 nicotinic acetylcholine receptor (α7nAChR) is a orchestrator of cholinergic anti-inflammatory pathway (CAP), which refers to a physiological neuro-immune mechanism that restricts inflammation. Here, we investigated the potential role of CAP in neointimal hyperplasia using α7nAChR knockout (KO) mice. Male α7nAChR-KO mice and their wild-type control mice (WT) were subjected to wire injury in left common carotid artery. At 4 weeks post injury, the injured aortae were isolated for examination. The neointimal hyperplasia after wire injury was significantly aggravated in α7nAChR-KO mice compared with WT mice. The α7nAChR-KO mice had increased collagen contents and vascular smooth muscle cells (VSMCs) amount. Moreover, the inflammation was significantly enhanced in the neointima of α7nAChR-KO mice relative to WT mice, evidenced by the increased expression of tumor necrosis factor-α/interleukin-1β, and macrophage infiltration. Meanwhile, the chemokines chemokine (C-C motif) ligand 2 and chemokine (CXC motif) ligand 2 expression was also augmented in the neointima of α7nAChR-KO mice compared with WT mice. Additionally, the depletion of superoxide dismutase (SOD) and reduced glutathione (GSH), and the upregulation of 3-nitrotyrosine, malondialdehyde and myeloperoxidase were more pronounced in neointima of α7nAChR-KO mice compared with WT mice. Accordingly, the protein expression of NADPH oxidase 1 (Nox1), Nox2 and Nox4, was also higher in neointima of α7nAChR-KO mice compared with WT mice. Finally, pharmacologically activation of CAP with a selective α7nAChR agonist PNU-282987, significantly reduced neointima formation, arterial inflammation and oxidative stress after vascular injury in C57BL/6 mice. In conclusion, our results demonstrate that α7nAChR-mediated CAP is a neuro-physiological mechanism that inhibits neointima formation after vascular injury via suppressing arterial inflammation and oxidative stress. Further, these results imply that targeting α7nAChR may be a promising interventional strategy for in-stent stenosis.