Modulation of Sirt1/NF-κB interaction of evogliptin is attributed to inhibition of vascular inflammatory response leading to attenuation of atherosclerotic plaque formation

SIRT-associated attenuation of cellular senescence in vascular wall

This review focuses on the vital function that SIRT1 and other sirtuins play in promoting cellular senescence in vascular smooth muscle cells, which is a key element in the pathogenesis of vascular aging and associated cardiovascular diseases. Vascular aging is a gradual process caused by the accumulation of senescent cells, which results in increased vascular remodeling, stiffness, and diminished angiogenic ability. Such physiological alterations are characterized by a complex interplay of environmental and genetic variables, including oxidative stress and telomere attrition, which affect gene expression patterns and trigger cell growth arrest. SIRT1 has been highlighted for its potential to reduce cellular senescence through modulation of multiple signaling cascades, particularly the endothelial nitric oxide (eNOS)/NO signaling pathway. It also modulates cell cycle through p53 inactivation and suppresses NF-κB mediated expression of adhesive molecules at the vascular level. The study also examines the therapeutic potential of sirtuin modulation in vascular health, identifying SIRT1 and its sirtuin counterparts as potential targets for reducing vascular aging. This study sheds light on the molecular basis of vascular aging and the beneficial effects of sirtuins, paving the way for the development of tailored therapies aimed at enhancing vascular health and prolonging life.

SIRT1 and thrombosis

Thrombosis is a major cause of morbidity and mortality worldwide, with a complex and multifactorial pathogenesis. Recent studies have shown that SIRT1, a member of the sirtuin family of NAD + -dependent deacetylases, plays a crucial role in regulating thrombosis, modulating key pathways including endothelial activation, platelet aggregation, and coagulation. Furthermore, SIRT1 displays anti-inflammatory activity both in vitro, in vivo and in clinical studies, particularly via the reduction of oxidative stress. On these bases, several studies have investigated the therapeutic potential of targeting SIRT1 for the prevention of thrombosis. This review provides a comprehensive and critical overview of the main preclinical and clinical studies and of the current understanding of the role of SIRT1 in thrombosis.

Platelet factor 4 (PF4) induces cluster of differentiation 40 (CD40) expression in human aortic endothelial cells (HAECs) through the SIRT1/NF-κB/p65 signaling pathway

PF4 is a pro-atherosclerotic molecule. Endothelial CD40, upon binding to its ligand CD40L, induces endothelial cell (EC) activation, which is a vital pathophysiological process in the initiation and progression of atherosclerosis. However, the relationship between PF4 and endothelial CD40 remains elusive. This study aims to investigate whether and how PF4 affects endothelial CD40 expression using primary HAECs. PF4 treatment down-regulated sirtuin 1 (SIRT1) expression but upregulated the expression of acetylated NF-κB p65 (Ac-p65) and CD40 in HAECs in a concentration- and time-dependent manner. Pretreatment with SIRT1 agonist (SRT1720 or RSV) or SIRT1-overexpressing lentivirus attenuated PF4-induced Ac-p65 and CD40 expression in HAECs, whereas preincubation with SIRT1 antagonist (NAM or EX527) or SIRT1 shRNA had the opposite effect. To investigate whether NF-κB/p65 signaling pathway modulates CD40 expression in PF4-treated HAECs, PDTC, a NF-κB inhibitor, and p65-shRNA were introduced. PDTC or p65-shRNA treatment down-regulated Ac-p65 expression in HAECs. PDTC or p65-shRNA preincubation suppressed CD40 expression in HAECs after PF4 treatment. To better determine whether SIRT1 regulates CD40 expression in PF4-treated HAECs via the NF-κB/p65 signaling pathway, p65-knockdown HAECs were preincubated with SIRT1 agonists before PF4 treatment. SIRT1 agonist preincubation further decreased CD40 expression in p65-knockdown HAECs treated with PF4. Moreover, PF4 treatment promoted p65 nuclear translocation in HAECs. The results of dual luciferase assay demonstrated that four NF-κB binding sites in the promoter of human CD40 gene were activated in PF4-treated HAECs. In conclusion, our findings suggest that PF4 treatment facilitates CD40 expression in HAECs through the SIRT1/NF-κB/p65 pathway.

Sirtuins: Promising Therapeutic Targets to Treat Ischemic Stroke

Stroke is a major cause of mortality and disability globally, with ischemic stroke (IS) accounting for over 80% of all stroke cases. The pathological process of IS involves numerous signal molecules, among which are the highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent enzymes known as sirtuins (SIRTs). SIRTs modulate various biological processes, including cell differentiation, energy metabolism, DNA repair, inflammation, and oxidative stress. Importantly, several studies have reported a correlation between SIRTs and IS. This review introduces the general aspects of SIRTs, including their distribution, subcellular location, enzyme activity, and substrate. We also discuss their regulatory roles and potential mechanisms in IS. Finally, we describe the current therapeutic methods based on SIRTs, such as pharmacotherapy, non-pharmacological therapeutic/rehabilitative interventions, epigenetic regulators, potential molecules, and stem cell-derived exosome therapy. The data collected in this study will potentially contribute to both clinical and fundamental research on SIRTs, geared towards developing effective therapeutic candidates for future treatment of IS.

Evogliptin, a DPP-4 inhibitor, prevents diabetic cardiomyopathy by alleviating cardiac lipotoxicity in db/db mice

Dipeptidyl peptidase-4 (DPP-4) inhibitors are glucose-lowering drugs for type 2 diabetes mellitus (T2DM). We investigated whether evogliptin® (EVO), a DPP-4 inhibitor, could protect against diabetic cardiomyopathy (DCM) and the underlying mechanisms. Eight-week-old diabetic and obese db/db mice were administered EVO (100 mg/kg/day) daily by oral gavage for 12 weeks. db/db control mice and C57BLKS/J as wild-type (WT) mice received equal amounts of the vehicle. In addition to the hypoglycemic effect, we examined the improvement in cardiac contraction/relaxation ability, cardiac fibrosis, and myocardial hypertrophy by EVO treatment. To identify the mechanisms underlying the improvement in diabetic cardiomyopathy by EVO treatment, its effect on lipotoxicity and the mitochondrial damage caused by lipid droplet accumulation in the myocardium were analyzed. EVO lowered the blood glucose and HbA1c levels and improved insulin sensitivity but did not affect the body weight or blood lipid profile. Cardiac systolic/diastolic function, hypertrophy, and fibrosis were improved in the EVO-treated group. EVO prevented cardiac lipotoxicity by reducing the accumulation of lipid droplets in the myocardium through suppression of CD36, ACSL1, FABP3, PPARgamma, and DGAT1 and enhancement of the phosphorylation of FOXO1, indicating its inhibition. The EVO-mediated improvement in mitochondrial function and reduction in damage were achieved through activation of PGC1a/NRF1/TFAM, which activates mitochondrial biogenesis. RNA-seq results for the whole heart confirmed that EVO treatment mainly affected the differentially expressed genes (DEGs) related to lipid metabolism. Collectively, these findings demonstrate that EVO improves cardiac function by reducing lipotoxicity and mitochondrial injury and provides a potential therapeutic option for DCM.

Evogliptin Directly Inhibits Inflammatory and Fibrotic Signaling in Isolated Liver Cells

Chronic liver inflammation can lead to fibrosis, cirrhosis, and hepatocellular carcinoma. Kupffer cells (KC) secrete proinflammatory and fibrogenic cytokines in response to lipopolysaccharide (LPS), and so play an important role in liver inflammation, where they induce hepatocellular damage. LPS also activates hepatic stellate cells and induces extracellular matrix deposition. In this study, we used isolated primary KC, primary hepatocytes, and primary hepatic stellate cells (HSC) to investigate whether evogliptin directly inhibits inflammatory and fibrotic signaling. We found that evogliptin inhibited LPS-induced secretion of inducible nitric oxide synthase and transforming growth factor β (TGF-β) from KC. Moreover, evogliptin inhibited inflammatory mediator release from hepatocytes and hepatic stellate cell activation that were induced by KC-secreted cytokines. In hepatocytes, evogliptin also inhibited LPS-induced expression of proinflammatory cytokines and fibrotic TGF-β. In addition, evogliptin inhibited TGF-β-induced increases in connective tissue growth factor levels and HSC activation. These findings indicate that evogliptin inhibits inflammatory and fibrotic signaling in liver cells. We also showed that the inhibitory effect of evogliptin on inflammatory and fibrotic signaling is associated with the induction of autophagy.

Dirty Jobs: Macrophages at the Heart of Cardiovascular Disease

Cardiovascular disease (CVD) is one of the greatest public health concerns and is the leading cause of morbidity and mortality in the United States and worldwide. CVD is a broad yet complex term referring to numerous heart and vascular conditions, all with varying pathologies. Macrophages are one of the key factors in the development of these conditions. Macrophages play diverse roles in the maintenance of cardiovascular homeostasis, and an imbalance of these mechanisms contributes to the development of CVD. In the current review, we provide an in-depth analysis of the diversity of macrophages, their roles in maintaining tissue homeostasis within the heart and vasculature, and the mechanisms through which imbalances in homeostasis may lead to CVD. Through this review, we aim to highlight the potential importance of macrophages in the identification of preventative, diagnostic, and therapeutic strategies for patients with CVD.

Expression and mechanism of microRNA 195 in diabetic retinopathy

We aimed to explore the role of microRNA 195 (miR-195) in diabetic retinopathy (DR). From January 2019 to July 2020, 50 patients with DR undergoing vitrectomy and 40 patients with idiopathic macular holes undergoing vitrectomy were selected as the observation group (OG) and control group (CG), respectively. The mRNA and protein expression levels of miR-195, SIRT1, BAX, and BCL-2 were detected in the retinal tissues obtained from the two groups during surgery. In addition, human retinal endothelial cells and human dermal microvascular endothelial cells were cultured in a high-glucose environment to detect the targeted relationship between miR-195 and SIRT1; determine the mRNA and protein expression levels of SIRT1, BAX, and BCL-2 after miR-195 knockdown; and assess the levels of cell proliferation and apoptosis. In OG, the mRNA and protein expression levels of miR-195 and BAX were high, whereas those of BCL-2 and SIRT1 were low. Moreover, we detected a targeted relationship between miR-195 and SIRT1. Conversely, miR-195 knockdown led to the downregulation of the mRNA and protein expression levels of BAX and the upregulation of the mRNA and protein expression levels of SIRT1 and BCL-2 as well as improvement in cell growth and a decrease in the apoptosis rate. miR-195 is overexpressed in DR, and its targeted relationship with SIRT1 inhibits the growth of cells in the retina and accelerates apoptosis.

Ovatodiolide protects ischemia-reperfusion-induced neuronal injury via microglial neuroinflammation via mediating SIRT1/NF-κB pathway

BACKGROUND

Ovatodiolide (OVA), a bioactive substance extracted from the bioactive component of Anisomeles indica, is reported to be endowed with anti-inflammatory properties. Nonetheless, its function in ischemia-reperfusion (I/R)-induced neurological deficits and microglial inflammation remains unclear.

METHOD

A middle cerebral artery occlusion (MCAO) model was set up in SD rats, which were then dealt with varying doses of OVA. The rats' neurological functions were estimated at diverse periods postoperatively. The dry and wet method, triphenyl tetrazolium chloride (TTC) staining, and Nissl's staining were conducted to measure brain edema, cerebral infarction area and neuronal damage, respectively. Immunohistochemistry (IHC) was performed to detect neuronal apoptosis and microglial activation, and the profiles of inflammatory factors in the cerebral tissues were estimated by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). In-vitro assays were implemented on HT22 neuronal cells and BV2 microglia to elaborate the effect of OVA against oxygen-glucose deprivation (OGD)-mediated effects.

RESULTS

OVA relieved HT22 cell apoptosis and eased inflammation in BV2 microglia, which were induced by OGD. OVA mitigated NF-κB phosphorylation in BV2 cells, whereas boosted SIRT1 expression. However, inhibiting SIRT1 abolished the anti-inflammatory effects of OVA in BV2 microglia under OGD stimulation. The condition medium (CM) of OGD-treated BV2 cells enhanced HT22 cell apoptosis and damage. OVA treatment in BV2 cells relieved BV2-mediated injury on HT22 cells, which was reversed by SIRT1 inhibitor. In-vivo results revealed that OVA dose-dependently attenuated I/R rats' neurological deficits, reduced brain edema, cerebral infarction area, neuronal apoptosis and microglial overactivation. Additionally, OVA inactivated the NF-κB pathway and up-regulated SIRT1 in the I/R rat model.

CONCLUSION

OVA prevented rats from brain I/R damage by hampering neuronal apoptosis and microglial inflammation via the SIRT1-NF-κB pathway.

DATA AVAILABILITY

The data sets used and analyzed during the current study are available from the corresponding author on reasonable request.

Circ-Sirt1 inhibits vascular smooth muscle cells proliferation via the c-Myc/cyclin B1 axis

Vascular smooth muscle cells（VSMCs）are an important cellular component of vascular wall. Restenosis is mainly due to VSMC excessive proliferation. However, little is known about the role of circRNAs in VSMC proliferation and phenotypic switching. Herein, using FISH assay and RT-qPCR, we found that circ-Sirt1 was markedly downregulated in neointimal formation after injury and in VSMCs treated with PDGF-BB. BrdU and MTT assays confirmed the inhibitory role of circ-Sirt1 on cell proliferation. Mechanistically, circ-Sirt1 was mainly expressed in the cytoplasm of VSMCs. Through RIP and RNA pull-down assays, we found that circ-Sirt1 bound c-Myc, protein associated with proliferation of VSMCs. ChIP assay also provided evidence that the overexpression of circ-Sirt1 almost ceased PDGF-BB-induced binding of c-Myc to the promoter of cyclin B1 in VSMCs. These results indicated that circ-Sirt1 had an inhibitory effect on c-Myc activity, providing a mechanism for suppressing PDGF-BB-induced VSMC proliferation by direct interactions with c-Myc and its sequestration in the cytoplasm. Overall, our study demonstrated that a previously unrecognized circ-Sirt1/c-Myc/cyclin B1 axis in VSMCs mediates neointimal formation following injury. This article is protected by copyright. All rights reserved.

Anti-Inflammatory Effects of Heliangin from Jerusalem Artichoke (Helianthus tuberosus) Leaves Might Prevent Atherosclerosis

Atherosclerosis is considered the major cause of cardiovascular and cerebrovascular diseases, which are the leading causes of death worldwide. Excessive nitric oxide production and inflammation result in dysfunctional vascular endothelial cells, which are critically involved in the initiation and progression of atherosclerosis. The present study aimed to identify a bioactive compound from Jerusalem artichoke leaves with anti-inflammatory activity that might prevent atherosclerosis. We isolated bioactive heliangin that inhibited NO production in LPS-induced macrophage-like RAW 264.7 cells. Heliangin suppressed ICAM-1, VCAM-1, E-selectin, and MCP-1 expression, as well as NF-κB and IκBα phosphorylation, in vascular endothelial cells stimulated with TNF-α. These results suggested that heliangin suppresses inflammation by inhibiting excessive NO production in macrophages and the expression of the factors leading to the development of atherosclerosis via the NF-κB signaling pathway in vascular endothelial cells. Therefore, heliangin in Jerusalem artichoke leaves could function in the prevention of atherosclerosis that is associated with heart attacks and strokes.

Long non-coding RNA RP11-490M8.1 inhibits lipopolysaccharide-induced pyroptosis of human umbilical vein endothelial cells via the TLR4/NF-κB pathway

BACKGROUND AND AIMS

Pyroptosis is a relatively newly discovered form of programmed cell death that plays an important role in the development of atherosclerosis. Many studies have reported that lncRNAs participated in the regulation of atherosclerosis development. However, the regulatory mechanism of lncRNAs in pyroptosis must be studied further.

METHODS

In a previous study, microarray analysis was used to detect the lncRNA expression profile in three human advanced atherosclerotic plaques and three normal arterial intimae. In the present research, in vitro assays were performed to investigate the role of lncRNA RP11-490M8.1 on pyroptosis. The relative gene mRNA and lncRNA expression levels were tested by quantitative real-time PCR, and protein levels were evaluated by western blot analysis. The RNA hybrid structure was analyzed using the DINAMelt server.

RESULTS

The lncRNA RP11-490M8.1 was significantly downregulated in atherosclerotic plaques and serum. Lipopolysaccharide (LPS) markedly reduced the expression of lncRNA RP11-490M8.1 and induced pyroptosis by increasingthe mRNA and protein levels of NLRP3, caspase-1, ASC, IL-1β, and IL-18 in HUVECs. The promotion effects ofLPS on pyroptosis were markedly suppressed by overexpression of lncRNA RP11-490M8.1. In addition, LPS increased the mRNA and protein levels ofTLR4 and NF-κB, which was also markedly offsetby overexpression of lncRNA RP11-490M8.1.

CONCLUSIONS

These findings indicated that lncRNA RP11-490M8.1 inhibited LPS-induced pyroptosis via the TLR4/NF-κB pathway. Thus, lncRNA RP11-490M8.1 may provide a therapeutic target to ameliorate atherosclerosis.

Evogliptin Suppresses Calcific Aortic Valve Disease by Attenuating Inflammation, Fibrosis, and Calcification

Calcific aortic valve disease (CAVD) accompanies inflammatory cell infiltration, fibrosis, and ultimately calcification of the valve leaflets. We previously demonstrated that dipeptidyl peptidase-4 (DPP-4) is responsible for the progression of aortic valvular calcification in CAVD animal models. As evogliptin, one of the DPP-4 inhibitors displays high specific accumulation in cardiac tissue, we here evaluated its therapeutic potency for attenuating valvular calcification in CAVD animal models. Evogliptin administration markedly reduced calcific deposition accompanied by a reduction in proinflammatory cytokine expression in endothelial nitric oxide synthase-deficient mice in vivo, and significantly ameliorated the mineralization of the primary human valvular interstitial cells (VICs), with a reduction in the mRNA expression of bone-associated and fibrosis-related genes in vitro. In addition, evogliptin ameliorated the rate of change in the transaortic peak velocity and mean pressure gradients in our rabbit model as assessed by echocardiography. Importantly, evogliptin administration in a rabbit model was found to suppress the effects of a high-cholesterol diet and of vitamin D2-driven fibrosis in association with a reduction in macrophage infiltration and calcific deposition in aortic valves. These results have indicated that evogliptin prohibits inflammatory cytokine expression, fibrosis, and calcification in a CAVD animal model, suggesting its potential as a selective therapeutic agent for the inhibition of valvular calcification during CAVD progression.

MicroRNA-217 modulates inflammation, oxidative stress, and lung injury in septic mice via SIRT1

Inflammation and oxidative stress contribute to the initiation and progression of septic lung injury. MicroRNA-217 (miR-217) is proved to be involved in controlling inflammatory response and oxidative stress, yet its role and underlying mechanism in the pathogenesis of septic lung injury remain elusive. Caecal ligation and puncture surgery were performed to generate sepsis in vivo and mice were kept for 12 h to imitate septic lung injury. Next, mice were administrated with miR-217 antagomir or agomir to decrease or increase the expression of miR-217 in lung tissue. Moreover, primary peritoneal macrophages were separated and incubated with lipopolysaccharide (LPS) to further verify the role of miR-217 in vitro. miR-217 was upregulated in septic lungs and primary macrophages. miR-217 antagomir alleviated, whereas miR-217 agomir aggravated inflammation and oxidative stress in septic mice and LPS-stimulated macrophages. Further detection identified SIRT1 was responsible for miR-217 antagomir-mediated anti-inflammatory and anti-oxidant effects, and SIRT1 inhibition abolished the beneficial effects of miR-217 antagomir in vivo and in vitro. Our data defined miR-217 as a therapeutic target for treating septic lung injury.

Efficacy and Safety of Novel Dipeptidyl-Peptidase-4 Inhibitor Evogliptin in the Management of Type 2 Diabetes Mellitus: A Meta-Analysis

AIMS

No meta-analysis is available which has summarized and holistically analyzed the efficacy and safety of evogliptin. We undertook this meta-analysis to address this gap in knowledge.

METHODS

Electronic databases were searched for RCTs involving diabetes patients receiving evogliptin in intervention arm and placebo/active comparator in control arm. Primary outcome was to evaluate changes in HbA1c. Secondary outcomes were to evaluate alterations in fasting glucose, postprandial glucose, lipids, insulin resistance, patients achieving glycemic targets of HbA1c <7% and <6.5%, and adverse events.

RESULTS

From initially screened 57 articles, data from six RCTs involving 887 patients was analyzed [three having sitagliptin/linagliptin as active comparator; three having placebo in control group]. Evogliptin was noninferior to sitagliptin/linagliptin regarding HbA1c reduction at 12 weeks [mean difference (MD) -0.06%; 95%CI: -0.23-0.11%; P = 0.48] and 24 weeks (MD 0.04%; 95%CI: -0.11-0.19%; P = 0.60) follow-up. Evogliptin was superior to placebo regarding HbA1c reduction at 12-weeks (MD -0.57%; 95%CI: -0.62- -0.52%; P < 0.001) and 24 weeks (MD -0.28%; 95%CI: -0.47 - -0.09%; P = 0.004). Evogliptin was noninferior to sitagliptin/linagliptin regarding patients achieving HbA1c <7% and <6.5% at 12 weeks and 24 weeks follow-up. Total adverse events [Risk ratio (RR) 0.98; 95% CI: 0.72-1.32; P = 0.89] and severe adverse events (RR 0.65; 95% CI: 0.25-1.67; P = 0.37) were not significantly different among groups. Patients receiving evogliptin did not have increased symptomatic (RR 0.46; 95% CI: 0.10-2.16; P = 0.32) and asymptomatic (RR 1.09; 95% CI: 0.61-1.97; P = 0.77) hypoglycaemia.

CONCLUSION

Evogliptin is well tolerated and has good glycemic efficacy over 6 months use for T2DM management.

Association between Proinflammatory Markers, Leukocyte-Endothelium Interactions, and Carotid Intima-Media Thickness in Type 2 Diabetes: Role of Glycemic Control

Glycated hemoglobin monitorization could be a tool for maintaining type 2 diabetes (T2D) under control and delaying the appearance of cardiovascular events. This cross-sectional study was designed to assess the role of glycemic control in modulating early-stage markers of cardiovascular complications. One hundred and eight healthy controls and 161 type 2 diabetic patients were recruited and distributed according to their glycemic control, setting the threshold at 6.5% (good control). Biochemical and anthropometrical parameters were registered during the initial visit, and peripheral blood was extracted to obtain polymorphonuclear cells and analyze inflammatory markers, adhesion molecules, leukocyte-endothelium interactions, and carotid intima-media thickness. Correlations between these parameters were explored. We found that inflammatory markers and adhesion molecules were augmented in type 2 diabetic subjects with poor glycemic control. Polymorphonuclear leukocytes interacted more with the endothelium in the diabetic population, and even more significantly in the poorly controlled subjects. In parallel, carotid intima-media thickness was also increased in the diabetic population, and the difference was greater among poorly controlled subjects. Finally, correlation measurement revealed that carotid intima-media thickness was related to glycemic control and lipid metabolism in diabetic patients. Our results suggest that glycemic control delays the onset of cardiovascular comorbidities in diabetic subjects.

Crucial Gene Identification in Carotid Atherosclerosis Based on Peripheral Blood Mononuclear Cell (PBMC) Data by Weighted (Gene) Correlation Network Analysis (WGCNA)

Background

Many patients are not responsive or tolerant to medical therapies for carotid atherosclerosis. Thus, elucidating the molecular mechanism for the pathogenesis and progression of carotid atherosclerosis and identifying new potential molecular targets for medical therapies that can slow progression of carotid atherosclerosis and prevent ischemic events are quite important.

Material/Methods

We downloaded the expression profiling data of PBMC in Biobank of Karolinska Endarterectomy (BiKE, GSE21545) for GEO. The WGCNA and DEG screening were conducted. The co-expression pattern between patients with ischemic events (the events group) and patients without ischemic events (the no-events group) were compared. Then, we identified hub genes of each module. Finally, the DEG co-expression network was constructed and MCODE was used to identify crucial genes based on this co-expression network.

Results

In the study, 183 DEGs were screened and 8 and 6 modules were assessed in the events group and no-events group, respectively. Compared to the no-events group, genes associated with inflammation and immune response were clustered in the green-yellow module of the events group. The hub gene of the green-yellow module of the events group was KIR2DL5A. We obtained 1 DEG co-expression network, which has 16 nodes and 24 edges, and we detected 5 crucial genes: SIRT1, THRAP3, RBM43, PEX1, and KLHDC2. The upregulated genes (THRAP3 and RBM43) showed potential diagnostic and prognostic value for the occurrence of ischemic events.

Conclusions

We detected 8 modules for the events group and 6 modules for the no-events group. The hub genes for modules and crucial genes of the DEG co-expression network were also identified. These genes might serve as potential targets for medical therapies and biomarkers for diagnosis and prognosis. Further experimental and biological studies are needed to elucidate the role of these crucial genes in the progression of carotid atherosclerosis.

MicroRNA-29b-3p Promotes Human Retinal Microvascular Endothelial Cell Apoptosis via Blocking SIRT1 in Diabetic Retinopathy

Background

Diabetic retinopathy (DR) is a main complication of diabetes mellitus (DM). Recent studies have implicated microRNAs in human retinal microvascular endothelial cell (HRMEC) dysfunction. In this study, we aim to investigate the apoptotic promotion of miR-29b-3p by blocking SIRT1 in HRMEC for DR situation.

Method

Blood samples were obtained from DR patients and controls. Dual-luciferase reporter assay using HEK-293T cells was performed to show the direct interaction of miR-29b-3p and the 3′UTR of SIRT1. HRMECs were exposed to 5.5 mmol/L of glucose (normal control), 5.5 mmol/L of glucose and 24.5 mmol/L of mannitol (osmotic pressure control), 30 mmol/L of glucose [hyperglycemia (HG)], 150 μmol/L of CoCl₂ (hypoxia), and 30 mmol/L of glucose plus 150 μmol/L of CoCl₂ (HG-CoCl₂). To identify the regulating relationship between miR-29b-3p and SIRT1, HRMECs were transfected with miR-29b-3p mimics/inhibitors or their negative controls. SRT1720 was used as a SIRT1 agonist. Cell viability was assessed with the cell counting kit-8 (CCK-8) assay, and apoptotic cells were stained by one-step terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay kit. Gene and protein expression were assayed by quantitative real-time reverse transcriptase-PCR (RT-qPCR) and western blotting separately.

Result

MiR-29b-3p was upregulated to 3.2-fold, and SIRT1 protein was downregulated to 65% in DR patients. Dual-luciferase reporter assay showed the direct interaction of miR-29b-3p and SIRT1. HRMECs were identified as >95% positive for CD31 and von Willebrand factor (vWF). MiR-29b-3p and Bax/Bcl-2 ratio was upregulated, whereas SIRT1 was downregulated in HRMECs in the HG-CoCl₂ condition. Decreased cell viability and upregulated apoptosis were also found in HRMECs of the HG-CoCl₂ condition. Upregulated miR-29b-3p decreased the expression of SIRT1 and increased the ratio of Bax/Bcl-2, whereas downregulated miR-29b-3p increased the expression of SIRT1 protein and downregulated the ratio of Bax/Bcl-2. SRT1720 rescued miR-29b-3p-induced HRMEC apoptosis via upregulating the expression of SIRT1 protein.

Conclusion

The dysregulation of miR-29b-3p/SIRT1 is a potential mechanism of HRMEC apoptosis in DR. MiR-29b-3p/SIRT1 may be a potential therapeutic target for DR.