NLRP3 inflammasome activation contributes to VSMC phenotypic transformation and proliferation in hypertension

Role of the signal transducer and activator of transcription 3 protein in the proliferation of vascular smooth muscle cells

OBJECTIVES

Cardiovascular disease (CVD) remains the primary cause of morbidity and mortality worldwide. The abnormal proliferation of vascular smooth muscle cells (VSMCs) is a key event in the pathogenesis of CVD. The functional and phenotypic changes in vascular cells are mediated by complex signaling cascades that initiate and control genetic reprogramming. Many studies have demonstrated that signal transducer and activator of transcription 3 (STAT3) regulates a diverse array of functions relevant to atherosclerosis.

METHODS

In this review, we summarize the studies on the STAT3-mediated proliferation of VSMCs and subsequent CVDs such as hypertension, atherosclerosis, stroke, coronary artery disease, and myocardial infarction. Furthermore, we describe the general background of STAT3, its structure, function and regulation as well as the STAT3 signaling pathway. Finally, we highlight some potential issues and propose some solutions to these issues.Results and conclusions: STAT3 activation promotes the proliferation of VSMCs by regulating the transcription of genes. Studying the mechanism of VSMC proliferation induced by the STAT3 pathway is valuable for finding therapeutic targets for CVD.

Diurnal Timing Dependent Alterations in Gut Microbial Composition Are Synchronously Linked to Salt-Sensitive Hypertension and Renal Damage

Alterations of diurnal rhythms of blood pressure (BP) and reshaping of gut microbiota are both independently associated with hypertension. However, the relationships between biorhythms of BP and gut microbial composition are unknown. We hypothesized that diurnal timing-associated alterations of microbial compositions are synchronous with diurnal rhythmicity, dip in BP, and renal function. To test this hypothesis, Dahl salt-sensitive (S) rats on low- and high-salt diets were examined for time of day effects on gut microbiota, BP, and indicators of renal damage. Major shifts in night and day patterns of specific groups of microbiota were observed between the dark (active) and light (rest) phases, which correlated with diurnal rhythmicity of BP. The diurnal abundance of Firmicutes, Bacteroidetes, and Actinobacteria were independently associated with BP. Discrete bacterial taxa were observed to correlate independently or interactively with one or more of the following 3 factors: (1) BP rhythm, (2) dietary salt, and (3) dip in BP. Phylogenetic Investigation of Communities revealed diurnal timing effects on microbial pathways, characterized by upregulated biosynthetic processes during the active phase of host, and upregulated degradation pathways of metabolites in the resting phase. Additional metagenomics functional pathways with rhythm variations were noted for aromatic amino acid metabolism and taurine metabolism. These diurnal timing dependent changes in microbiota, their functional pathways, and BP dip were associated with concerted effects of the levels of renal lipocalin 2 and kidney injury molecule-1 expression. These data provide evidence for a firm and concerted diurnal timing effects of BP, renal damage, and select microbial communities.

FNDC5 Attenuates Oxidative Stress and NLRP3 Inflammasome Activation in Vascular Smooth Muscle Cells via Activating the AMPK-SIRT1 Signal Pathway

Vascular oxidative stress and inflammation play a major role in vascular diseases. This study was aimed at determining the protective roles of fibronectin type III domain-containing 5 (FNDC5) in angiotensin II- (Ang II-) induced vascular oxidative stress and inflammation and underlying mechanisms. Wild-type (WT) and FNDC5^−/− mice, primary mouse vascular smooth muscle cells (VSMCs), and the rat aortic smooth muscle cell line (A7R5) were used in the present study. Subcutaneous infusion of Ang II caused more serious hypertension, vascular remodeling, oxidative stress, NLRP3 inflammasome activation, AMPK phosphorylation inhibition, and SIRT1 downregulation in the aorta of FNDC5^−/− mice than those of WT mice. Exogenous FNDC5 attenuated Ang II-induced superoxide generation, NADPH oxidase 2 (NOX2) and NLRP3 upregulation, mature caspase-1, and interleukin-1β (IL-1β) production in A7R5 cells. The protective roles of FNDC5 were prevented by SIRT-1 inhibitor EX527, AMPK inhibitor compound C, or integrin receptor inhibitor GLPG0187. FNDC5 attenuated the Ang II-induced inhibition in SIRT1 activity, SIRT1 protein expression, and AMPKα phosphorylation in A7R5 cells, which were prevented by compound C, EX527, and GLPG0187. FNDC5 deficiency deteriorated Ang II-induced oxidative stress, NLRP3 inflammasome activation, AMPK phosphorylation inhibition, and SIRT1 downregulation in primary aortic VSMCs of mice, which were prevented by exogenous FNDC5. These results indicate that FNDC5 deficiency aggravates while exogenous FNDC5 alleviates the Ang II-induced vascular oxidative stress and NLRP3 inflammasome activation via the AMPK-SIRT1 signal pathway in VSMCs.

Regulation of NLRP3 inflammasome by CD38 through cADPR-mediated Ca2+ release in vascular smooth muscle cells in diabetic mice

AIMS

NLR family pyrin domain containing 3 (NLRP3) inflammasome activation contributes to the development of diabetic cardiovascular complications. CD38 regulates vascular inflammation through cyclic ADP-ribose (cADPR)-mediated Ca²⁺ signaling in vascular smooth muscle cells (VSMCs). Ca²⁺ mobilization may modulate inflammasome activation by impacting mitochondrial function. However, it remains unclear whether CD38 regulates NLRP3 inflammasome activation in VSMCs through cADPR-dependent Ca²⁺ release under diabetic condition. Main methods and key findings: In VSMCs, we observed that high glucose (HG, 30 mM) enhanced CD38 protein expression and ADP ribosyl cyclase activity. Moreover, along with less abundance of NLRP3, apoptosis-associated speck-like protein containing CARD (ASC) and their colocalization, the expression of active caspase-1(p20) and IL-1β were significantly inhibited by CD38 gene deficiency with siRNA transfection in VSMCs. Further, CD38 regulated the release of intracellular cADPR-mediated Ca²⁺ and mitochondrial DNA (mtDNA) to the cytosol, which was associated with NLRP3 inflammasome activation and VSMCs proliferation and collagen I synthesis. Finally, we found that CD38 inhibitors, nicotinamide and telmisartan significantly improved the endothelium-independent contraction and vascular remodeling, which was also associated with the inhibition of NLRP3 inflammasome in the aorta media in the diabetic mice.

SIGNIFICANCE

Our data suggested that CD38/cADPR-mediated Ca²⁺ signaling contributed to the mitochondrial damage, consequently released mtDNA to the cytosol, which was related with NLRP3 inflammasome activation and VSMCs remodeling in diabetic mice.

Mitochondrial dysfunction/NLRP3 inflammasome axis contributes to angiotensin II-induced skeletal muscle wasting via PPAR-γ

Angiotensin II (Ang II) levels are elevated in patients with chronic kidney disease or heart failure, and directly causes skeletal muscle wasting in rodents, but the molecular mechanisms of Ang II-induced skeletal muscle wasting and its potential as a therapeutic target are unknown. We investigated the NLR family pyrin domain containing 3 (NLRP3) inflammasome-mediated muscle atrophy response to Ang II in C2C12 myotubes and Nlrp3 knockout mice. We also assessed the mitochondrial dysfunction (MtD)/NLRP3 inflammasome axis in Ang II-induced C2C12 myotubes. Finally, we examined whether a peroxisome proliferator-activated receptor-γ (PPAR-γ) agonist could attenuate skeletal muscle wasting by targeting the MtD/NLRP3 inflammasome axis in vitro and in vivo. We demonstrated that Ang II increased NLRP3 inflammasome activation in cultured C2C12 myotubes dose dependently. Nlrp3 knockdown or Nlrp3^-/- mice were protected from the imbalance of protein synthesis and degradation. Exposure of C2C12 to Ang II increased mitochondrial ROS (mtROS) generation, accompanied by MtD. Remarkably, the mitochondrial-targeted antioxidant not only decreased mtROS and MtD, it also significantly inhibited NLRP3 inflammasome activation and restored skeletal muscle atrophy. Finally, the PPAR-γ agonist protected against Ang II-induced muscle wasting by preventing MtD, oxidative stress, and NLRP3 inflammasome activation in vitro and in vivo. This work suggests a potential role of MtD/NLRP3 inflammasome pathway in the pathogenesis of Ang II-induced skeletal muscle wasting, and targeting the PPAR-γ/MtD/NLRP3 inflammasome axis may provide a therapeutic approach for muscle wasting.

MicroRNA‑24 attenuates diabetic vascular remodeling by suppressing the NLRP3/caspase‑1/IL‑1β signaling pathway

Vascular remodeling plays an important role in the pathogenesis of diabetic cardiovascular complications. Previous published research has indicated that microRNA-24 (miR-24) is involved in diabetic vascular remodeling, but the underlying molecular mechanisms have yet to be fully elucidated. The aim of the present study was to investigate whether adenovirus-mediated miR-24 overexpression can suppress the NOD-like receptor family pyrin domain-containing 3 (NLRP3)-related inflammatory signaling pathway and attenuate diabetic vascular remodeling. The carotid arteries of diabetic rats were harvested and prepared for analysis. Reverse transcription-quantitative PCR and western blotting assays were used to detect the expressions of related mRNAs and proteins. Morphological examinations, including hematoxylin and eosin, immunohistochemical and Masson’s trichrome staining, were also performed. The results of the present study demonstrated that miR-24 upregulation suppressed neointimal hyperplasia and accelerated reendothelialization in the injured arteries, lowered the expression of NLRP3, apoptosis-associated speck-like protein, caspase-1, proliferating cell nuclear antigen, CD45, interleukin (IL)-1β, IL-18 and tumor necrosis factor-α, and increased the expression of CD31, smooth muscle (SM) α-actin and SM-myosin heavy chain. These data indicated that miR-24 overexpression can attenuate vascular remodeling in a diabetic rat model through suppressing the NLRP3/caspase-1/IL-1β signaling pathway.

Phenolic Compounds Exerting Lipid-Regulatory, Anti-Inflammatory and Epigenetic Effects as Complementary Treatments in Cardiovascular Diseases

Atherosclerosis is the main process behind cardiovascular diseases (CVD), maladies which continue to be responsible for up to 70% of death worldwide. Despite the ongoing development of new and potent drugs, their incomplete efficacy, partial intolerance and numerous side effects make the search for new alternatives worthwhile. The focus of the scientific world turned to the potential of natural active compounds to prevent and treat CVD. Essential for effective prevention or treatment based on phytochemicals is to know their mechanisms of action according to their bioavailability and dosage. The present review is focused on the latest data about phenolic compounds and aims to collect and correlate the reliable existing knowledge concerning their molecular mechanisms of action to counteract important risk factors that contribute to the initiation and development of atherosclerosis: dyslipidemia, and oxidative and inflammatory-stress. The selection of phenolic compounds was made to prove their multiple benefic effects and endorse them as CVD remedies, complementary to allopathic drugs. The review also highlights some aspects that still need clear scientific explanations and draws up some new molecular approaches to validate phenolic compounds for CVD complementary therapy in the near future.

The Role of NLRP3 Inflammasome in Radiation-Induced Cardiovascular Injury

The increasing risk of long-term adverse effects from radiotherapy on the cardiovascular structure is receiving increasing attention. However, the mechanisms underlying this increased risk remain poorly understood. Recently, the nucleotide-binding domain and leucine-rich-repeat-containing family pyrin 3 (NLRP3) inflammasome was suggested to play a critical role in radiation-induced cardiovascular injury. However, the relationship between ionizing radiation and the NLRP3 inflammasome in acute and chronic inflammation is complex. We reviewed literature detailing pathological changes and molecular mechanisms associated with radiation-induced damage to the cardiovascular structure, with a specific focus on NLRP3 inflammasome-related cardiovascular diseases. We also summarized possible therapeutic strategies for the prevention of radiation-induced heart disease (RIHD).

Trimethylamine-N-Oxide Promotes Vascular Calcification Through Activation of NLRP3 (Nucleotide-Binding Domain, Leucine-Rich-Containing Family, Pyrin Domain-Containing-3) Inflammasome and NF-κB (Nuclear Factor κB) Signals

Objectives:

Vascular calcification is highly prevalent in patients with chronic kidney disease. Increased plasma trimethylamine N-oxide (TMAO), a gut microbiota-dependent product, concentrations are found in patients undergoing hemodialysis. However, a clear mechanistic link between TMAO and vascular calcification is not yet established. In this study, we investigate whether TMAO participates in the progression of vascular calcification using in vitro, ex vivo, and in vivo models.

Approach and Results:

Alizarin red staining revealed that TMAO promoted calcium/phosphate-induced calcification of rat and human vascular smooth muscle cells in a dose-dependent manner, and this was confirmed by calcium content assay. Similarly, TMAO upregulated the expression of bone-related molecules including Runx2 (Runt-related transcription factor 2) and BMP2 (bone morphogenetic protein-2), suggesting that TMAO promoted osteogenic differentiation of vascular smooth muscle cells. In addition, ex vivo study also showed the positive regulatory effect of TMAO on vascular calcification. Furthermore, we found that TMAO accelerated vascular calcification in rats with chronic kidney disease, as indicated by Mico-computed tomography analysis, alizarin red staining and calcium content assay. By contrast, reducing TMAO levels by antibiotics attenuated vascular calcification in chronic kidney disease rats. Interestingly, TMAO activated NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3) inflammasome and NF-κB (nuclear factor κB) signals during vascular calcification. Inhibition of NLRP3 inflammasome and NF-κB signals attenuated TMAO-induced vascular smooth muscle cell calcification.

Conclusions:

This study for the first time demonstrates that TMAO promotes vascular calcification through activation of NLRP3 inflammasome and NF-κB signals, suggesting the potential link between gut microbial metabolism and vascular calcification. Reducing the levels of TMAO could become a potential treatment strategy for vascular calcification in chronic kidney disease.

Lamin A/C negatively regulated by miR-124-3p modulates apoptosis of vascular smooth muscle cells during cyclic stretch application in rats

AIM

Apoptosis of vascular smooth muscle cells (VSMCs) influenced by abnormal cyclic stretch is crucial for vascular remodelling during hypertension. Lamin A/C, a nuclear envelope protein, is mechano-responsive, but the role of lamin A/C in VSMC apoptosis is still unclear.

METHODS

FX-5000T Strain Unit provided cyclic stretch (CS) in vitro. AnnexinV/PI and cleaved Caspase 3 ELISA detected apoptosis. qPCR was used to investigate the expression of miR-124-3p and a luciferase reporter assay was used to evaluate the ability of miR-124-3p binding to the Lmna 3'UTR. Protein changes of lamin A/C and relevant molecules were detected using western blot. Ingenuity Pathway Analysis and Protein/DNA array detected the potential transcription factors. Renal hypertensive rats verified these changes.

RESULTS

High cyclic stretch (15%-CS) induced VSMC apoptosis and repressed lamin A/C expressions compared with normal (5%-CS) control. Downregulation of lamin A/C enhanced VSMC apoptosis. In addition, 15%-CS had no significant effect on mRNA expression of Lmna, and lamin A/C degradation was not induced by autophagy. 15%-CS elevated miR-124-3p bound to the 3'UTR of Lmna and negatively regulated protein expression of lamin A/C. Similar changes occurred in renal hypertensive rats compared with sham controls. Lamin A/C repression affected activity of TP53, CREB1, MYC, STAT1/5/6 and JUN, which may in turn affect apoptosis.

CONCLUSION

Our data suggested that the decreased expression of lamin A/C upon abnormal cyclic stretch and hypertension may induce VSMC apoptosis. These mechano-responsive factors play important roles in VSMC apoptosis and might be novel therapeutic targets for vascular remodelling in hypertension.

The pharmacological properties of chrysophanol, the recent advances

As a universal Chinese medicine, Rhei Radix et Rhizoma was used for centuries in different fields including pharmaceutical, health care and cosmetics. Chrysophanol (Chr) is one of the most important anthraquinone components isolated from plants of the Rheum genus. Current reports show that in Rheum officinale, Chr is the most abundant free anthraquinone compound [1] and exerts a number of beneficial effects, such as anti-inflammation, anti-cancer, and anti-depressive effects and offers neuroprotection. We collected information about Chr from the Internet databases PubMed, Web of Science, Europe PMC and CNKI with a combination of keywords including "Chr", "Pharmacology", and "Pharmacokinetics". All data about this ingredient in this review were extracted from articles published before September 2019. Based on the literature found, we concluded that (1) Chr exhibited potential anti-inflammation, anti-cardiovascular disease (CVD)and anti-cancer activities by regulating signaling pathway transduction (NF-κB, MAPK, PI3K/Akt, etc.); (2) compared with free Chr, pharmacokinetic studies revealed that other forms of Chr, such as nanoparticle-based and liposome-based Chr, showed high bioavailability. Nevertheless, we also found that the understanding of the exact differences in the regulation of multiple molecular signaling pathways is in a preliminary stage and needs to be clarified. Moreover, further studies are required to determine the apoptotic mechanism of Chr in cancer cells. Finally, we found that (3) structure modification studies demonstrated potential relationships between structure and drug activity. The purpose of this review is to summarize the pharmacological activities, intracorporal processes and structure-activity relationships of Chr and to provide an up-to-date reference for further research and clinical applications.

Nucleotide-Binding Oligomerization Domain-Like Receptor Protein 3 Deficiency in Vascular Smooth Muscle Cells Prevents Arteriovenous Fistula Failure Despite Chronic Kidney Disease

Background

The arteriovenous fistula (AVF) is the preferred hemodialysis access for patients with chronic kidney disease. Chronic kidney disease can increase neointima formation, which greatly contributes to AVF failure by an unknown mechanism. Our study aimed to determine the role of nucleotide‐binding oligomerization domain‐like receptor protein 3 (NLRP3) in neointima formation induced by experimental AVFs in the presence of chronic kidney disease.

Methods and Results

From our findings, NLRP3 was upregulated in the intimal lesions of AVFs in both uremic mice and patients. Smooth muscle–specific knockout NLRP3 mice exhibited markedly decreased neointima formation in the outflow vein of AVFs. Compared with primary vascular smooth muscle cells isolated from control mice, those isolated from smooth muscle–specific knockout NLRP3 mice showed compromised proliferation, migration, phenotypic switching, and a weakened ability to activate mononuclear macrophages. To identify how NLRP3 functions, several small‐molecule inhibitors were used. The results showed that NLRP3 regulates smooth muscle cell proliferation and migration through Smad2/3 phosphorylation rather than through caspase‐1/interleukin‐1 signaling. Unexpectedly, the selective NLRP3‐inflammasome inhibitor MCC950 also repressed Smad2/3 phosphorylation and relieved chronic kidney disease–promoted AVF failure independent of macrophages.

Conclusions

Our findings suggest that NLRP3 in vascular smooth muscle cells may play a crucial role in uremia‐associated AVF failure and may be a promising therapeutic target for the treatment of AVF failure.

Salusin-β Promotes Vascular Calcification via Nicotinamide Adenine Dinucleotide Phosphate/Reactive Oxygen Species-Mediated Klotho Downregulation

Aims: Vascular calcification (VC) is a hallmark feature of cardiovascular disease and a significant risk factor for morbidity and mortality. Salusin-β exerts cardiovascular regulating effects in hypertension, atherosclerosis, and diabetes. The present study was designed to examine the roles of salusin-β in the progression of VC and its downstream signaling mechanisms. Results: Salusin-β expression in both the aortas of VC rats induced by vitamin D3 and nicotine and vascular smooth muscle cells (VSMCs) incubated with calcifying media was increased. Salusin-β knockdown remarkably reduced VC, whereas overexpression of salusin-β exacerbated VC both in vitro and in vivo. Overexpression of salusin-β promoted the VSMC osteochondrogenic transition, decreased Klotho protein levels, enhanced Ras-related C3 botulinum toxin substrate 1 (Rac1) activity and the translocation of p47phox to the membrane, increased the expression of nicotinamide adenine dinucleotide phosphate [NAD(P)H] oxidase subunits and the production of reactive oxygen species (ROS) with or without calcifying media; however, salusin-β deficiency played the opposite roles. The calcification and downregulated Klotho protein levels induced by salusin-β were restored by ROS scavenger N-acetyl-l-cysteine, diphenyleneiodonium chloride [an inhibitor of flavin-containing enzyme, including NAD(P)H oxidase], or gene knockdown of NAD(P)H oxidase (NOX)-2, p22phox, or p47phox but were not affected by NOX-1 and NOX-4 knockdown. Klotho knockdown attenuated the protective effect of salusin-β deficiency on VSMC calcification. By contrast, exogenous Klotho ameliorated the development of VC and ROS generation induced by salusin-β overexpression. Innovation: Salusin-β is a critical modulator in VC. Conclusion: Salusin-β regulates VC through activation of NAD(P)H/ROS-mediated Klotho downregulation, suggesting that salusin-β may be a novel target for treatment of VC.

MiR155-5p in adventitial fibroblasts-derived extracellular vesicles inhibits vascular smooth muscle cell proliferation via suppressing angiotensin-converting enzyme expression

Proliferation of vascular smooth muscle cells (VSMCs) plays crucial roles in vascular remodelling and stiffening in hypertension. Vascular adventitial fibroblasts are a key regulator of vascular wall function and structure. This study is designed to investigate the roles of adventitial fibroblasts-derived extracellular vesicles (EVs) in VSMC proliferation and vascular remodelling in normotensive Wistar-Kyoto rat (WKY) and spontaneously hypertensive rat (SHR), an animal model of human essential hypertension. EVs were isolated from aortic adventitial fibroblasts of WKY (WKY-EVs) and SHR (SHR-EVs). Compared with WKY-EVs, miR155-5p content was reduced, while angiotensin-converting enzyme (ACE) content was increased in SHR-EVs. WKY-EVs inhibited VSMC proliferation of SHR, which was prevented by miR155-5p inhibitor. SHR-EVs promoted VSMC proliferation of both strains, which was enhanced by miR155-5p inhibitor, but abolished by captopril or losartan. Dual luciferase reporter assay showed that ACE was a target gene of miR155-5p. MiR155-5p mimic or overexpression inhibited VSMC proliferation and ACE upregulation of SHR. WKY-EVs reduced ACE mRNA and protein expressions while SHR-EVs only increased ACE protein level in VSMCs of both strains. However, the SHR-EVs-derived from the ACE knockdown-treated adventitial fibroblasts lost the roles in promoting VSMC proliferation and ACE upregulation. Systemic miR155-5p overexpression reduced vascular ACE, angiotensin II and proliferating cell nuclear antigen levels, and attenuated hypertension and vascular remodelling in SHR. Repetitive intravenous injection of SHR-EVs increased blood pressure and vascular ACE contents, and promoted vascular remodelling in both strains, while WKY-EVs reduced vascular ACE contents and attenuated hypertension and vascular remodelling in SHR. We concluded that WKY-EVs-mediated miR155-5p transfer attenuates VSMC proliferation and vascular remodelling in SHR via suppressing ACE expression, while SHR-EVs-mediated ACE transfer promotes VSMC proliferation and vascular remodelling.

Curcumin Management of Myocardial Fibrosis and its Mechanisms of Action: A Review

Myocardial fibrosis is implicated as a leading risk factor for heart failure, arrhythmia, and sudden death after cardiac injury, as the excessive interstitial extracellular matrix impedes heart contraction and electrical conduction. Complicated mechanisms involving oxidative stress, pro-inflammatory cytokines, chemokine families, NLRP3 inflammasomes, growth factors, and non-coding RNAs participate in cardiac fibrogenesis and make it difficult to designate specific and effective therapies. Oriental herbs have been popular for thousands of years in the health care of Asian residents, due to their multi-targeted, multi-faceted approaches and their multi-functional effects in fighting difficult and complicated diseases, including cardiovascular disorders such as myocardial fibrosis. Curcumin, a natural polyphenol and yellow pigment obtained from the spice turmeric, was found to have strong anti-oxidant and anti-inflammatory properties. Increasing evidence has shown that curcumin can be used to prevent and treat myocardial fibrosis, when the myocardium suffers pathological pro-fibrotic changes in vivo and in vitro. The present review focuses on recent studies elucidating the mechanisms of curcumin in treating different pathologic conditions, including ischemia, hypoxia/reoxygenation, pressure or volume overload, and hyperglycemia or high-fat-induced cardiac fibrosis. Novel analogs such as C66, B2BrBC, Y20, and J17 have been designed to maximize the therapeutic potentials of curcumin. These optimized curcumin analogs with improved bioavailability and pharmacokinetic profiles need to be clinically verified before curcumin could be recommended for the treatment of myocardial fibrosis.

MicroRNA-223-3p modulates dendritic cell function and ameliorates experimental autoimmune myocarditis by targeting the NLRP3 inflammasome

Autoimmune myocarditis is a cause of dilated cardiomyopathy and heart failure. MicroRNAs regulate many immune processes, but their role in aberrant inflammation during autoimmune myocarditis remains unclear. In this study, we investigated the role of miR-223-3p in experimental autoimmune myocarditis (EAM). We found that miR-223-3p expression was significantly lower in EAM mice than that in normal mice. miR-223-3p inhibited NLRP3 inflammasome expression, promoting the polarization of dendritic cells (DCs) towards a tolerogenic DC phenotype. miR-223-3p effectively induced regulatory T cell (Treg) generation by inhibiting the function of antigen-presenting DCs. Transfer of miR-223-3p-overexpressing DCs protected mice against the development of EAM. Our findings suggest that miR-223-3p is involved in the induction of the tolerogenic DC phenotype and regulates tolerance in autoimmune myocarditis.

Inhibition of vascular neointima hyperplasia by FGF21 associated with FGFR1/Syk/NLRP3 inflammasome pathway in diabetic mice

BACKGROUND AND AIMS

Neointima hyperplasia is the pathological basis of atherosclerosis and restenosis, which have been associated with diabetes mellitus (DM). Fibroblast growth factor 21 (FGF21) is a potential diabetic drug, however, it has not been investigated whether FGF21 prevents neointima hyperplasia in DM.

METHODS

Vascular neointima hyperplasia was induced in mice fed a high fat diet (HFD) combined with low dose streptozotocin (STZ) administration. In vitro, vascular smooth muscle cells (VSMCs) were incubated with high glucose (HG, 30 mM). VSMC proliferation and migration, as well as formation of NLRP3 inflammasome, were assessed.

RESULTS

We found that FGF21 significantly inhibited neointima hyperplasia and improved endothelium-independent contraction in the wire-injured common carotid artery (CCA) of diabetic mice. In vitro, the proliferation and migration of HG-treated VSMCs were shown as remarkable increase of PCNA, cyclin D1, MMP2 and MMP9, as well as cell migration through wound healing and transwell migration assays. Such abnormal changes were dramatically reversed by FGF21, which mimicked the role of NLRP3 inflammasome inhibitor MCC950 and caspase-1 inhibitor WEHD. Moreover, along with more NLRP3, ASC oligomer and their colocalization, the release of active caspase-1(p20) and IL-1β was significantly inhibited by FGF21 in VSMCs exposed to HG. Furthermore, FGF21 suppressed phosphorylation of spleen tyrosine kinase (Syk) via FGFR1, which regulated NLRP3 inflammasome through ASC phosphorylation and oligomerization.

CONCLUSIONS

We demonstrated that potential protection of FGF21 on VSMCs proliferation and migration was associated with inhibition of FGFR1/Syk/NLRP3 inflammasome, resulting in the improvement of neointima hyperplasia in diabetic mice.

Metformin represses the pathophysiology of AAA by suppressing the activation of PI3K/AKT/mTOR/autophagy pathway in ApoE-/- mice

Background

The protective effect of metformin (MET) on abdominal aortic aneurysm (AAA) has been reported. However, the related mechanism is still poor understood. In this study, we deeply investigated the role of metformin in AAA pathophysiology.

Methods

Angiotensin II (Ang-II) was used to construct the AAA model in ApoE^−/− mice. The related mechanism was explored using Western blot and quantitative real time PCR (qRT-PCR). We also observed the morphological changes in the abdominal aorta and the influence of metformin on biological behaviors of rat abdominal aortic VSMCs.

Results

The PI3K/AKT/mTOR pathway was activated in aneurysmal wall tissues of AAA patients and rat model. Treatment with metformin inhibited the breakage and preserved the elastin structure of the aorta, the loss of collagen, and the apoptosis of aortic cells. In addition, metformin significantly suppressed the activation of the PI3K/AKT/mToR pathway and decreased the mRNA and protein levels of LC3B and Beclin1, which were induced by Ang-II. Moreover, PI3K inhibitors enhanced the effect of metformin while PI3K agonists largely reversed this effect. Interestingly, the cell proliferation, apoptosis, migration and autophagy of vascular smooth muscle cells (VSMCs) induced by Ang-II were also decreased following metformin treatment. PI3K inhibitors and agonists strengthened and weakened the effects of metformin in VSMCs, respectively.

Conclusions

Metformin represses the pathophysiology of AAA by inhibiting the activation of PI3K/AKT/mTOR/autophagy pathway. This repression may be useful as a new therapeutic strategy for AAA.

Curcumin attenuates migration of vascular smooth muscle cells via inhibiting NFκB-mediated NLRP3 expression in spontaneously hypertensive rats

Migration of vascular smooth muscle cell (VSMC) plays a critical role in the pathophysiology of hypertension and several other vascular diseases. Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a bioactive constituent from Curcuma longa, is commonly used as a spice, food additive or dietary pigment. It has several health benefits including antioxidant, anti-inflammatory and anticancer properties. This study examined the roles of curcumin in VSMC migration in hypertension and underlying mechanism. VSMC was isolated and prepared from thoracic aorta of Wistar-Kyoto rats and spontaneously hypertensive rats (SHR). VSMC migration was evaluated with Boyden chamber assay and wound-healing assay. Curcumin attenuated VSMC migration, inhibited nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) expression and reduced interleukin (IL)-1β concentration in VSMC of SHR, which were similar to the effects of NLRP3 knockdown on IL-1β concentration and VSMC migration. Curcumin inhibited NFκB activation in VSMC of SHR, which was similar to the effects of NFκB inhibitor BAY11-7082 on NFκB activation. In another in vitro model of rat VSMC migration, curcumin also inhibited angiotensin II-induced VSMC migration, NFκB activation, NLRP3 expression and IL-1β production. Intragastric administration of curcumin in SHR attenuated hypertension and reduced NFκB activation, NLRP3 and matrix metalloproteinase-9 expressions and aortic media thickness. These results indicate that curcumin inhibits VSMC migration via inhibiting NFκB-mediated NLRP3 expression in VSMC of SHR or in angiotensin II-treated VSMC. Curcumin attenuates hypertension, vascular inflammation and vascular remodeling in SHR.

miR-125a-5p inhibits the expression of NLRP3 by targeting CCL4 in human vascular smooth muscle cells treated with ox-LDL

Recent findings have revealed that aberrant miR-125a-5p expression is involved in the development of atherosclerosis. The present study aimed to investigate the precise mechanism of microRNA (miR)-125a-5p in atherosclerosis. Human vascular smooth muscle cells (HVSMCs) were treated with 20 µg/ml oxidized low-density lipoprotein (ox-LDL) for 24 h and were employed as in vitro models of atherosclerosis. Reverse transcription quantitative (RT-qPCR) assays were used to detect miR-125a-5p levels. Immunofluorescence analysis was conducted to assess α-smooth muscle actin (α-SMA) expression. Western blotting and RT-qPCR assays were performed to measure the expression levels of NACHT, LRR and PYD domains-containing protein 3 (NLRP3), apoptosis associated speck-like protein (ASC), caspase-1, active interleukin (IL)-1β and C-C motif chemokine 4-like (CCL4). Furthermore, the association between miR-125a-5p and CCL4 was assessed using a double luciferase analysis. In addition, VSMCs were transfected with miR-125a-5p mimics (30 nM), miR-125a-5p inhibitor (100 nM) or small interfering RNA against CCL4 (si-CCL4, 50 pM), respectively to further investigate the function of miR-125a-5p in ox-LDL-treated HVSMCs. The present study found that the expression levels of miR-125a-5p were significantly downregulated in HVSMCs, whereas the expression levels of α-SMA, NLRP3, ASC, caspase-1, IL-1β and CCL4 were markedly upregulated following ox-LDL treatment. Overexpression of miR-125a-5p in the absence of ox-LDL treatment decreased NLRP3, IL-1β and CCL4 expression, whereas inhibition of miR-125a-5p exhibited the opposite effects. The results of double luciferase analysis confirmed that CCL4 was a direct target of miR-125a-5p. Moreover, transfection of si-CCL4 into HVSMCs significantly decreased the ox-LDL-induced expression of NLRP3, ASC, caspase-1 and IL-1β proteins. Taken collectively, the results of the present study suggested that miR-125a-5p could negatively regulate the NLRP3 inflammasome by targeting CCL4 in ox-LDL-treated HVSMCs. The data provide new insight to the inhibition of atherosclerosis progression.

Single Mild Traumatic Brain Injury Induces Persistent Disruption of the Blood-Brain Barrier, Neuroinflammation and Cognitive Decline in Hypertensive Rats

Traumatic brain injury (TBI) induces blood-brain barrier (BBB) disruption, which contributes to secondary injury of brain tissue and development of chronic cognitive decline. However, single mild (m)TBI, the most frequent form of brain trauma disrupts the BBB only transiently. We hypothesized, that co-morbid conditions exacerbate persistent BBB disruption after mTBI leading to long term cognitive dysfunction. Since hypertension is the most important cerebrovascular risk factor in populations prone to mild brain trauma, we induced mTBI in normotensive Wistar and spontaneously hypertensive rats (SHR) and we assessed BBB permeability, extravasation of blood-borne substances, neuroinflammation and cognitive function two weeks after trauma. We found that mTBI induced a significant BBB disruption two weeks after trauma in SHRs but not in normotensive Wistar rats, which was associated with a significant accumulation of fibrin and increased neuronal expression of inflammatory cytokines TNFα, IL-1β and IL-6 in the cortex and hippocampus. SHRs showed impaired learning and memory two weeks after mild TBI, whereas cognitive function of normotensive Wistar rats remained intact. Future studies should establish the mechanisms through which hypertension and mild TBI interact to promote persistent BBB disruption, neuroinflammation and cognitive decline to provide neuroprotection and improve cognitive function in patients with mTBI.

Sex-Specific Mechanisms in Inflammation and Hypertension

PURPOSE OF REVIEW

Despite enhanced screening and therapeutic management, hypertension remains the most prevalent chronic disease in the United States and the leading cause of heart disease, chronic kidney disease, and stroke in both men and women. It is widely accepted that hypertension is a pro-inflammatory disease and that the immune system plays a vital role in mediating hypertensive outcomes and end organ damage. Despite known discrepancies in the risk of hypertension development between men and women, preclinical models of immune-mediated hypertension were historically developed solely in male animals, leading to a lack of sex-specific clinical practice guidelines or therapeutic targets.

RECENT FINDINGS

Following the NIH policy on the consideration of sex as a biological variable in 2015, significant advancements have been made into sex-specific disease mechanisms in inflammation and hypertension. This review article serves to critically evaluate recent advancements in the field of sex-specific immune-mediated hypertension.

Validation of Phosphodiesterase-10 as a Novel Target for Pulmonary Arterial Hypertension via Highly Selective and Subnanomolar Inhibitors

Pulmonary arterial hypertension (PAH) causes pathological increase in pulmonary vascular resistance, leading to right-heart failure and eventual death. Previously, phosphodiesterase-10 (PDE10) was reported to be a promising target for PAH based on the studies with a nonselective PDE inhibitor papaverine, but little progress has been made to confirm the practical application of PDE10 inhibitors. To validate whether PAH is ameliorated by PDE10 inhibition rather than other PDE isoforms, here we report an integrated strategy to discover highly selective PDE10 inhibitors as chemical probes. Structural optimization resulted in a PDE10 inhibitor 2b with subnanomolar affinity and good selectivity of >45 000-fold against other PDEs. The cocrystal structure of the PDE10-2b complex revealed an important H-bond interaction between 2b and Tyr693. Finally, compound 2b significantly decreased the arterial pressure in PAH rats and thus validated the potential of PDE10 as a novel anti-PAH target. These findings suggest that PDE10 inhibition may be a viable treatment option for PAH.

Weighted Gene Co-expression Network Analysis for RNA-Sequencing Data of the Varicose Veins Transcriptome

Objective

Varicose veins are a common problem worldwide and can cause significant impairments in health-related quality of life, but the etiology and pathogenesis remain not well defined. This study aims to elucidate transcriptomic regulations of varicose veins by detecting differentially expressed genes, pathways and regulator genes.

Methods

We harvested great saphenous veins (GSV) from patients who underwent coronary artery bypass grafting (CABG) and varicose veins from conventional stripping surgery. RNA-Sequencing (RNA-Seq) technique was used to obtain the complete transcriptomic data of both GSVs from CABG patients and varicose veins. Weighted Gene Co-expression network analysis (WGCNA) and further analyses were then carried out with the aim to elucidate transcriptomic regulations of varicose veins by detecting differentially expressed genes, pathways and regulator genes.

Results

From January 2015 to December 2016, 7 GSVs from CABG patients and 13 varicose veins were obtained. WGCNA identified 4 modules. In the brown module, gene ontology (GO) analysis showed that the biological processes were focused on response to stimulus, immune response and inflammatory response, etc. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis showed that the biological processes were focused on cytokine-cytokine receptor interaction and TNF signaling pathway, etc. In the gray module, GO analysis showed that the biological processes were skeletal myofibril assembly related. The immunohistochemistry staining showed that the expression of ASC, Caspase-1 and NLRP3 were increased in GSVs from CABG patients compared with varicose veins. Histopathological analysis showed that in the varicose veins group, the thickness of vascular wall, tunica intima, tunica media and collagen/smooth muscle ratio were significantly increased, and that the elastic fiber/internal elastic lamina ratio was decreased.

Conclusion

This study shows that there are clear differences in transcriptomic information between varicose veins and GSVs from CABG patients. Some inflammatory RNAs are down-regulated in varicose veins compared with GSVs from CABG patients. Skeletal myofibril assembly pathway may play a crucial role in the pathogenesis of varicose veins. Characterization of these RNAs may provide new targets for understanding varicose veins diagnosis, progression, and treatment.

LncRNA MRAK048635_P1 is critical for vascular smooth muscle cell function and phenotypic switching in essential hypertension

Vascular remodeling caused by essential hypertension is a leading cause of death in patients, and vascular smooth muscle cell (VSMC) dysfunction and phenotypic switching result in vascular remodeling. Therefore, inhibiting cell dysfunction and phenotypic switching in VSMCs may be a new treatment strategy for essential hypertension. The aim of the current study is to explore the roles of long non-coding RNA (lncRNA) MRAK048635_P1 in VSMC function and phenotypic switching. The MRAK048635_P1 level was determined in spontaneously hypertensive rats (SHRs) and VSMCs isolated from SHRs. MRAK048635_P1 was knocked down using a specific siRNA in VSMCs isolated from the thoracic aorta of SHRs and Wistar–Kyoto rats. Then, the proliferation and migration of VSMCs were determined using a cell counting kit-8 (CCK-8), a ³H labeling method, a transwell assay, and a wound healing assay. Flow cytometry was used to test the effect of MRAK048635_P1 on VSMC apoptosis. The protein and mRNA levels of associated genes were measured through Western blotting, immunofluorescence, and Quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR). MRAK048635_P1 showed low expression during hypertension in vivo and in vitro. Down-regulation of lncRNA MRAK048635_P1 promoted proliferation and migration and inhibited apoptosis in VSMCs isolated from healthy rat vascular tissue and SHR-derived VSMCs. Importantly, we also found that down-regulation of MRAK048635_P1 could induce VSMC phenotypic switching from a contractile to a secretory phenotype. In conclusion, our findings reveal that decreased MRAK048635_P1 is probably an important factor for vascular remodeling by affecting VSMC cell function and phenotypic switching in essential hypertension.

Necrotic cell debris induces a NF-κB-driven inflammasome response in vascular smooth muscle cells derived from abdominal aortic aneurysms (AAA-SMC)

Abdominal aortic aneurysm (AAA) is a multi-factorial progressive vascular disease with life-threatening complications. Increasing evidence suggests that smooth muscle cell (SMC) dysfunction and cell death contribute to dilatation and rupture of the aorta by inducing an inflammatory response. The exact mechanism of this response however, is incompletely understood. We here investigated in vitro the capacity of autologous necrotic cell debris (CD) to induce inflammasome components and inflammatory mediators in aortic SMC (AAA-SMC) isolated from patients with AAA undergoing surgical repair. AAA-SMCs were additionally primed with Interferon- γ (IFN-γ) before treatment with CD in order to mimic the proinflammatory status caused by higher IFN-γ concentrations that have been demonstrated in the wall of AAAs. Real-time RT-PCR revealed that CD significantly increased NLRP3 and IL1B mRNA expression in different SMC cultures within 6 h of exposure. Priming of the AAA-SMC with IFN-γ significantly increased expression of NLRP3, AIM2, IFI16 and CASP1 mRNAs, whereas IL1B mRNA was reduced. Additional exposure of IFN-γ-primed AAA-SMC to CD for 6-24 h, further augmented expression of AIM2, NLRP3, and Caspase-1 protein levels. Analysis of the SMC supernatants by ELISA revealed CD-induced release of the senescence-associated cytokines IL-6 and MCP-1 in native and IFN-γ-primed SMC, whereas no secretion of Interleukin-(IL) 1α and IL-1β secretion were observed. Our results implicate a role of necrotic cell debris derived from dead neighboring cells in SMC dysfunction and in inflammatory response of AAA tissue.

SXBX pill suppresses homocysteine-induced vascular smooth muscle cells dedifferentiation by inhibiting NLRP3 inflammasomes activation via ERK/p38 MAPK pathways

The dedifferentiation of vascular smooth muscle cells (VSMCs) is a key event in the pathogenesis of vascular remodeling-related disease. The present study aimed to investigate the effects of shexiangbaoxin (SXBX) pill, a traditional Chinese medicinal formula on VSMCs dedifferentiation and its potential mechanisms. High-fat diet (HFD) was introduced to lipoprotein receptor-deficient (LDLR^-/-) mice to generate hyperhomocysteinemia (HHcy), and plasma Hcy and lipid levels were analyzed. The phenotype of VSMCs was assessed in mice with the treatment of low (45 mg/kg/d) or high (90 mg/kg/d) SXBX pill by measuring the contractile protein α-SMA, SM22α and synthetic proteins OPN using RT-qPCR, western blotting and immunofluorescence assay. In vitro, the proliferation, migration and dedifferentiation of VSMCs were measured by MTT, Edu incorporation, wound healing and western blotting assay. Small interfering RNA technology was used to examine the role of NLRP3 in the effects of SXBX pill on dedifferentiation. The results indicated that although SXBX pill had no influence on HFD-induced HHcy and hyperlipidaemia, it reversed HHcy-induced dedifferentiation of VSMCs in vivo. SXBX pill significantly inhibited proliferation, migration and dedifferentiation of Hcy-treated VSMCs. In addition, we found that Hcy activated NLRP3 inflammasomes in VSMCs and SXBX pill could attenuate NLRP3 inflammasomes activation. Moreover, subsequent analysis suggested that SXBX pill inhibited NLRP3 inflammasomes activation through regulation of ERK1/2 and p38 MAPK pathway. Knockdown of NLRP3 reversed the inhibitory effects of SXBX pill in VSMCs. In conclusion, SXBX pill inhibited Hcy-induced proliferation, migration and dedifferentiation of VSMCs by suppressing NLRP3 inflammasomes activation via of ERK/p38 MAPK pathway.

Rab7‑mediated autophagy regulates phenotypic transformation and behavior of smooth muscle cells via the Ras/Raf/MEK/ERK signaling pathway in human aortic dissection

Autophagy regulates the metabolism, survival and function of numerous types of cell, including cells that comprise the cardiovascular system. The dysfunction of autophagy has been demonstrated in atherosclerosis, restenotic lesions and hypertensive vessels. As a member of the Ras GTPase superfamily, Rab7 serves a significant role in the regulation of autophagy. The present study evaluated how Rab7 affects the proliferation and invasion, and phenotypic transformations of aortic dissection (AD) smooth muscle cells (SMCs) via autophagy. Rab7 was overexpressed in AD tissues and the percentage of synthetic human aortic SMCs (HASMCs) was higher in AD tissues compared with NAD tissues. Downregulation of Rab7 decreased cell growth, reduced the number of invasive cells and decreased the percentage cells in the G1 phase. Autophagy of HASMCs was inhibited following Rab7 knockdown. Inhibition of autophagy with 3‑methyladenine or Rab7 knockdown suppressed the phenotypic conversion of contractile to synthetic HASMCs. The action of Rab7 may be mediated by inhibiting the Ras/Raf/mitogen‑activated protein kinase (MAPK) kinase (MEK)/extracellular signal related kinase (ERK) signaling pathway. In conclusion, the results revealed that Rab7‑mediated autophagy regulated the behavior of SMCs and the phenotypic transformations in AD via activation of the Ras/Raf/MEK/ERK signaling pathway. The findings of the present study may improve understanding of the role Rab7 in the molecular etiology of AD and suggests the application of Rab7 as a novel therapeutic target in the treatment of human AD.

NLRP3 Inflammasome Is Involved in Calcium-Sensing Receptor-Induced Aortic Remodeling in SHRs

Increasing evidence suggests that the NLRP3 (nucleotide oligomerization domain-like receptor family, pyrin domain containing 3) inflammasome participates in cardiovascular diseases. However, its role and activation mechanism during hypertension remains unclear. In this study, we tested the role and mechanism of calcium-sensing receptor (CaSR) in NLRP3 inflammasome activation during hypertension. We observed that the expressions of CaSR and NLRP3 were increased in spontaneous hypertensive rats (SHRs) along with aortic fibrosis. In vascular smooth muscle cells (VSMCs), the activation of NLRP3 inflammasome associated with CaSR and collagen synthesis was induced by angiotensin II (Ang II). Furthermore, inhibition of CaSR and NLRP3 inflammasome attenuated proinflammatory cytokine release, suggesting that CaSR-mediated activation of the NLRP3 inflammasome may be a therapeutic target in aortic dysfunction and vascular inflammatory lesions.

NLRP7 is increased in human idiopathic fetal growth restriction and plays a critical role in trophoblast differentiation

Fetal growth restriction (FGR) the leading cause of perinatal mortality and morbidity is highly related to abnormal placental development, and placentas from FGR pregnancies are often characterized by increased inflammation. However, the mechanisms of FGR-associated inflammation are far from being understood. NLRP7, a member of a family of receptors involved in the innate immune responses, has been shown to be associated with gestational trophoblastic diseases. Here, we characterized the expression and the functional role of NLRP7 in the placenta and investigated its involvement in the pathogenesis of FGR. We used primary trophoblasts and placental explants that were collected during early pregnancy, and established trophoblast-derived cell lines, human placental villi, and serum samples from early pregnancy (n = 38) and from FGR (n = 40) and age-matched controls (n = 32). Our results show that NLRP7 (i) is predominantly expressed in the trophoblasts during the hypoxic period of placental development and its expression is upregulated by hypoxia and (ii) increases trophoblast proliferation ([³H]-thymidine) and controls the precocious differentiation of trophoblasts towards syncytium (syncytin 1 and 2 and β-hCG production and xCELLigence analysis) and towards invasive extravillous trophoblast (2D and 3D cultures). We have also demonstrated that NLRP7 inflammasome activation in trophoblast cells increases IL-1β, but not IL-18 secretion. In relation to the FGR, we demonstrated that major components of NLRP7 inflammasome machinery are increased and that IL-1β but not IL-18 circulating levels are increased in FGR. Altogether, our results identified NLRP7 as a critical placental factor and provided evidence for its deregulation in FGR. NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies. KEY MESSAGES: NLRP7 inflammasome is abundantly expressed by trophoblast cells. It is regulated by a key parameter of placental development, hypoxia. It controls trophoblast proliferation, migration, and invasion and exhibits anti-apoptotic role. NLRP7 machinery is deregulated in FGR pregnancies.

Urotensin II: an inflammatory cytokine

Urotensin II (UII) is a polypeptide molecule with neurohormone-like activity. It has been confirmed that UII is widely distributed in numerous organs of different animal species from fish to mammals, including humans. The UII receptor is orphan G-protein coupled receptor 14, also known as UT. The tissue distribution of UII and UT is highly consistent, and their expression may be regulated by autocrine and paracrine mechanisms. In the body, UII has many physiological and pathophysiological activities, such as vasoconstrictor and vasodilatory actions, cell proliferation, pro-fibrosis, neuroendocrine activity, insulin resistance, and carcinogenic and inflammatory effects, which have been recognized only in recent years. In fact, UII is involved in the process of inflammatory injury and plays a key role in the onset and development of inflammatory diseases. In this paper, we will review the roles UII plays in inflammatory diseases.

DNA Methylation and Histone Modification in Hypertension

Systemic hypertension, which eventually results in heart failure, renal failure or stroke, is a common chronic human disorder that particularly affects elders. Although many signaling pathways involved in the development of hypertension have been reported over the past decades, which has led to the implementation of a wide variety of anti-hypertensive therapies, one half of all hypertensive patients still do not have their blood pressure controlled. The frontier in understanding the molecular mechanisms underlying hypertension has now advanced to the level of epigenomics. Particularly, increasing evidence is emerging that DNA methylation and histone modifications play an important role in gene regulation and are involved in alteration of the phenotype and function of vascular cells in response to environmental stresses. This review seeks to highlight the recent advances in our knowledge of the epigenetic regulations and mechanisms of hypertension, focusing on the role of DNA methylation and histone modification in the vascular wall. A better understanding of the epigenomic regulation in the hypertensive vessel may lead to the identification of novel target molecules that, in turn, may lead to novel drug discoveries for the treatment of hypertension.

Nesfatin-1 promotes VSMC migration and neointimal hyperplasia by upregulating matrix metalloproteinases and downregulating PPARγ

The dedifferentiation, proliferation and migration of vascular smooth muscle cells (VSMCs) are essential in the progression of hypertension, atherosclerosis and intimal hyperplasia. Nesfatin-1 is a potential modulator in cardiovascular functions. However, the role of nesfatin-1 in VSMC biology has not been explored. The present study was designed to determine the regulatory role of nesfatin-1 in VSMC proliferation, migration and intimal hyperplasia after vascular injury. Herein, we demonstrated that nesfatin-1 promoted VSMC phenotype switch from a contractile to a synthetic state, stimulated VSMC proliferation and migration in vitro. At the molecular level, nesfatin-1 upregulated the protein and mRNA levels, as well as the promoter activities of matrix metalloproteinase 2 (MMP-2) and MMP-9, but downregulated peroxisome proliferator-activated receptor γ (PPARγ) levels and promoter activity in VSMCs. Blockade of MMP-2/9 or activation of PPARγ prevented the nesfatin-1-induced VSMC proliferation and migration. In vivo, knockdown of nesfatin-1 ameliorated neointima formation following rat carotid injury. Taken together, our results indicated that nesfatin-1 stimulated VSMC proliferation, migration and neointimal hyperplasia by elevating MMP2/MMP-9 levels and inhibiting PPARγ gene expression.

Salusin-β Is Involved in Diabetes Mellitus-Induced Endothelial Dysfunction via Degradation of Peroxisome Proliferator-Activated Receptor Gamma

The pathophysiological mechanisms for vascular lesions in diabetes mellitus (DM) are complex, among which endothelial dysfunction plays a vital role. Therapeutic target against endothelial injury may provide critical venues for treatment of diabetic vascular diseases. We recently identified that salusin-β contributed to high glucose-induced endothelial cell apoptosis. However, the roles of salusin-β in DM-induced endothelial dysfunction remain largely elusive. Male C57BL/6J mice were used to induce type 2 diabetes mellitus (T2DM) model. Human umbilical vein endothelial cells (HUVECs) were cultured in high glucose/high fat (HG/HF) medium. We demonstrated increased expression of salusin-β in diabetic aortic tissues and high-glucose/high-fat- (HG/HF-) incubated HUVECs. Disruption of salusin-β by shRNA abrogated the reactive oxygen species (ROS) production, inflammation, and nitrotyrosine content of HUVECs cultured in HG/HF medium. The HG/HF-mediated decrease in peroxisome proliferator-activated receptor γ (PPARγ) expression was restored by salusin-β shRNA, and PPARγ inhibitor T0070907 abolished the protective actions of salusin-β shRNA on endothelial injury in HG/HF-treated HUVECs. Salusin-β silencing obviously improved endothelium-dependent vasorelaxation, oxidative stress, inflammatory response, and nitrative stress in diabetic aorta. Taken together, our results highlighted the essential role of salusin-β in pathological endothelial dysfunction, and salusin-β may be a promising target in treatment of vascular complications of DM.