Activity Of Smooth Muscle Cells Research Articles

Abstract 12234: A Three-Dimensional Culture System Composed of Hipsc Derived Cms, Ecs, Smcs, and Cardiac Fibroblasts Promotes Hipsc-cm Maturation

Introduction: Cardiomyocytes (CMs), endothelial cells (ECs), smooth muscle cells (SMCs), and cardiac fibroblasts (CFs) differentiated from human induced-pluripotent stem cells (hiPSCs) are the fundamental components of cell-based regenerative myocardial therapy and can be used as in-vitro models for mechanistic studies and drug testing. However, newly differentiated hiPSC-CMs tend to more closely resemble fetal CMs than the mature CMs of adult hearts, and current techniques for improving CM maturation can be both complex and labor-intensive. Hypothesis: CMs tend to develop a more mature phenotype when cultured as spheroids in a three-dimensional (3D) environment, rather than as two-dimensional monolayers, and the activity of ECs, SMCs, and CFs promote both CM maturation and electrical activity. Methods: hiPSCs were differentiated into CMs (hiPSC-CMs) using a belly dancer shaker in 3D condition and seeded into 96-Well of Nunclon Sphera-Treated, U-Shaped-Bottom Microplate (Thermo Fisher Scientific). hiPSC differentiated endothelial cells (hiPSC-ECs), smooth muscle cells (hiPSC-SMCs), and cardiac fibroblasts (hiPSC-CFs) were added to each well to produce cardiac spheroids. Quantitative polymerase chain reaction (qPCR), western blot, immunostaining, bioenergetics, transmission electron microscopy, field potential, and contractility of cardiac spheroids were characterized. Results: The inclusion of hiPSC-ECs, -SMCs, and CFs in CM spheroids increased spheroid size and improved cell viability. hiPSC-ECs, -SMCs, and -CFs promoted hiPSC-CMs maturation in cardiac spheroids: a. gene expression levels of TNNI3, N-cadherin, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1a) significantly increased; b. Contractile fibers were better organized and mitochondria were better aligned; c. ATP level, the ratio of NAD:NADH, and cAMP level were greater in cardiac spheroids; d. Field-potential duration and conduction velocity were greater in CMs in cardiac spheroids. Conclusion: we developed a simple and reproducible 3D-culture-based process for generating cardiac spheroids containing more mature hiPSC-CMs in the presence of ECs, SMCs, and CFs.

Quercetin inhibits angiotensin II-induced vascular smooth muscle cell proliferation and activation of JAK2/STAT3 pathway: A target based networking pharmacology approach.

The rapid growth of vascular smooth muscle cells (VSMCs) represents crucial pathological changes during the development of hypertensive vascular remodeling. Although quercetin exhibits significantly therapeutic effects on antihypertension, the systematic role of quercetin and its exact mode of action in relation to the VSMCs growth and its hypertension-related networking pharmacology is not well-documented. Therefore, the effect of quercetin was investigated using networking pharmacology followed by in vitro strategies to explore its efficacy against angiotensin II (Ang II)-induced cell proliferation. Putative genes of hypertension and quercetin were collected using database mining, and their correlation was investigated. Subsequently, a network of protein-protein interactions was constructed and gene ontology (GO) analysis was performed to identify the role of important genes (including CCND1) and key signaling pathways [including cell proliferation and Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway]. We therefore further investigated the effects of quercetin in Ang II-stimulated VSMCs. This current research revealed that quercetin significantly reduced the cell confluency, cell number, and cell viability, as well as expression of proliferating cell nuclear antigen (PCNA) in Ang II-stimulated VSMCs. Mechanistic study by western blotting confirmed that quercetin treatment attenuated the activation of JAK2 and STAT3 by reducing its phosphorylation in Ang II stimulated VSMCs. Collectively, the current study revealed the inhibitory effects of quercetin on proliferation of Ang II stimulated VSMCs, by inhibiting the activation of JAK2/STAT3 signaling might be one of underlying mechanisms.

LncRNA MDRL Mitigates Atherosclerosis through miR-361/SQSTM1/NLRP3 Signaling.

Objective Long non-coding RNAs (lncRNAs) play many important roles in gene regulation and disease pathogenesis. Here, we sought to determine that mitochondrial dynamic related lncRNA (MDRL) modulates NLRP3 inflammasome activation and apoptosis of vascular smooth muscle cells (VSMCs) and protects arteries against atherosclerosis. Methods In vivo experiments, we applied LDLR knockout (LDLR−/−) mice fed the high-fat diet to investigate the effects of MDRL on atherosclerosis. In vitro experiments, we applied mouse aortic smooth muscle cells to determine the mechanism of MDRL in abrogating NLRP3 inflammasome and inhibiting cell apoptosis through miR-361/sequentosome 1 (SQSTM1) by TUNEL staining, quantitative RT-PCR, western blot, microribonucleoprotein immunoprecipitation, and luciferase reporter assay. Results Downregulated MDRL and increased NLRP3 were observed in mouse atherosclerotic plaques, accompanied with the increase of miR-361. The results showed that MDRL overexpression significantly attenuated the burden of atherosclerotic plaque and facilitated plaque stability through inhibiting NLRP3 inflammasome activation and cell apoptosis, and vice versa. Mechanically, MDRL suppressed NLRP3 inflammasome activation and VSMC apoptosis via suppressing miR-361. Furthermore, miR-361 directly bound to the 3'UTR of SQSTM1 and inhibited its translation, subsequently activating NLRP3 inflammasome. Systematic delivery of miR-361 partly counteracted the beneficial effects of MDRL overexpression on atherosclerotic development in LDLR−/− mice. Conclusions In summary, MDRL alleviates NLRP3 inflammasome activation and apoptosis in VSMCs through miR-361/SQSTM1/NLRP3 pathway during atherogenesis. These data indicate that MDRL and inhibition of miR-361 represent potential therapeutic targets in atherosclerosis-related diseases.

The synergistic mechanism of fibroblast growth factor 18 and integrin β1 in rat abdominal aortic aneurysm repair

BackgroundAbdominal aortic aneurysms have a high mortality rate. While surgery is the preferred treatment method, the biological repair of abdominal aortic aneurysms is being increasingly studied. We performed cellular and animal experiments to investigate the simultaneous function and mechanism of fibroblast growth factor 18 and integrin β1 in the biological repair of abdominal aortic aneurysms.MethodsEndothelial and smooth muscle cells of rat arteries were used for the cellular experiments. Intracellular integrin β1 expression was regulated through lentiviral transfection. Interventions with fibroblast growth factor 18 were determined according to the experimental protocol. Several methods were used to detect the expression of elastic fiber component proteins, cell proliferation, and migratory activity of endothelial and smooth muscle cells after different treatments. For animal experiments, abdominal aortic aneurysms were induced in rats by wrapping the abdominal aortae in sterile cotton balls soaked with CaCl2 solution. Fibroblast growth factor 18 was administered through tail vein injections. The local expression of integrin β1 was regulated through lentiviral injections into the adventitia of the abdominal aortic aneurysms. The abdominal aortae were harvested for pathological examinations and tensile mechanical tests.ResultsThe expression of integrin β1 in endothelial and smooth muscle cells could be regulated effectively through lentiviral transfection. Animal and cellular experiments showed that fibroblast growth factor 18 + integrin β1 could improve the expression of elastic fiber component proteins and enhance the migratory and proliferative activities of smooth muscle and endothelial cells. Moreover, animal experiments showed that fibroblast growth factor 18 + integrin β1 could enhance the aortic integrity to withstand stretch of aortic aneurysm tissue.ConclusionFibroblast growth factor 18 + integrin β1 improved the biological repair of abdominal aortic aneurysms in rats by increasing the expression of elastic proteins, improving the migratory and proliferative abilities of endothelial and smooth muscle cells, and improving aortic remodeling.

Effect of crosstalk between Th17 and Th9 cells on the activation of dermal vascular smooth muscle cells in systemic scleroderma and regulation of tanshinone IIA

BackgroundTo evaluate the effect of T-helper 17 (Th17) cells and Th9 cells on the activation of dermal vascular smooth muscle cells (DVSMCs) in systemic scleroderma (SSc) and regulation of tanshinone IIA. MethodsThe expression of interleukin 17 receptor (IL-17R) and interleukin 9 receptor (IL-9R) in the skin of SSc patients was assessed by immunofluorescence. The expression of IL-9 and IL-9R mRNA in peripheral blood mononuclear cells (PBMCs) of SSc patients were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The proportion of Th9 cells in PBMCs of SSc patients was sorted by flow cytometry. The effect of IL-9 on the differentiation of Th17 and IL-17 on that of Th9 was detected by flow cytometry. The proportion of Th9 and Th17 cells in SSc patients was detected by flow cytometry. The level of collagen I, III, α-SMA, IL-9R, IL-17R, JNK, P38, and ERK were analyzed using western blot (WB). ResultsTh9 cells were highly expressed in SSc. IL-9 stimulated the differentiation of immature T cells into Th17 cells. IL-17 induced the differentiation of immature T cells into Th9 cells. Tanshinone IIA inhibited the differentiation of immature T lymphocytes into Th17 and Th9. WB showed that the combined action of IL-17 and IL-9 upregulated the inflammation and proliferation of DVSMCs. Anti-IL17, anti-IL9, and tanshinone IIA inhibited the functional activation of DVSMCs. Study limitationsFor Th17, Th9 and vascular smooth muscle cells, the study on the signal pathway of their interaction is not thorough enough. More detailed studies are needed to explore the mechanism of cell-cell interaction. ConclusionsThe current results suggested that Th17 and Th9 cells induced the activation of DVSMCs in SSc through crosstalk in vitro, and tanshinone IIA inhibited the process.

Abstract P355: Involvement Of Nlrp3 Inflammasome In Vascular Injury-induced Neointimal Formation And PDGF-BB Stimulated Monocyte Retention And Pyroptosis In Arterial Smooth Muscle Cells

Intimal hyperplasia due to pathological vascular remodeling is a common feature of cardiovascular diseases such as atherosclerosis and restenosis after angioplasty. Nlrp3 inflammasome has been reported to trigger endothelial injury leading to pathological vascular remodeling in metabolic diseases. This study aimed to elucidate whether the Nlrp3 inflammasome in smooth muscle cells (SMCs) per se is involved in their phenotypic regulation and thereby contributes to pathological vascular remodeling. The ligation injury-induced neointimal hyperplasia model was established in hypercholesterolemic mice. Mice received a single intravenous injection of AAV encoding mutant mPCSK9 (rAAV8-D377Y-mPCSK9). Then mice received partial ligation surgery in left carotid artery (LCA) and consumed a high fat, high cholesterol diet for 4 weeks. The neointimal formation and various markers related to synthetic phenotype and Nlrp3 inflammasome pathways were assessed in ligated LCA. The collateral un-ligated right carotid artery (RCA) served as controls. Our data revealed that ligation injury induced neointimal formation in Nlrp3 +/+ mice, which was markedly attenuated in Nlrp3 -/- mice (intima area: Nlrp3 +/+ 15.97±4.07 μm 2 vs. Nlrp3 -/- 4.31±1.27 μm 2 ). Ligation injury drastically increased Nlrp3 inflammasome activation, monocyte adhesion, pyroptosis, and synthetic phenotype trans-differentiation in LCAs of Nlrp3 +/+ mice. These changes were largely limited in the SMC-enriched neointimal region and abrogated in Nlrp3 -/- mice. PDGF-BB, a ligation injury-associated factor promoting SMC synthetic phenotype transition, activated Nlrp3 inflammasomes in cultured SMCs. Inhibition of inflammasome-dependent caspase-1 by Ac-YVAD-cmk attenuated PDGF-BB-induced SMC-monocyte interaction and pyroptosis, whereas proliferation and migration of SMCs were unaffected. Together, these results suggest that in arterial SMCs, activation of Nlrp3 inflammasomes and subsequent events including induction of pyroptosis and adhesion of monocytes are essential for ligation injury-induced neointimal formation. These results provide new insight into the mechanisms of Nlrp3 inflammasome action in SMCs in pathological vascular remodeling in hypercholesterolemia.

Abstract 049: Abrogation Of Transglutaminase 2 In Vascular Smooth Muscle Cells Attenuates Doca/salt Induced Hypertension In Male Mice

Background: Transglutaminase 2 (TG2) is an enzyme involved in the pathogenesis of vascular remodeling in conditions of chronic over-nutrition and activation of the renin angiotensin aldosterone system (RAAS). Furthermore, it has been shown that pharmacologic inhibition of TG2 significantly reduces blood pressure in male rodents. However, the cell-specific role of TG2 activation in vascular smooth muscle cells (VSMC) in mediating the hypertensive response to RAAS overactivation has not been explored. Methods: We generated a novel inducible model (tamoxifen dose: 50 mg/kg/d oral for 6 weeks) of TG2 deletion in VSMC (VSMCTG2KO) by sequentially crossing Tgm2t/t floxed mice (loxP sites flanking exons 6-8 of the TG2, C polypeptide [Tgm2] gene) with male Myh11-CreERT2 positive mice. Effectiveness of the TG2 deletion was evaluated by immunohistochemistry and TG2 activity was determined by incorporation of Alexa Fluor488 Cadaverine.A cohort of fifteen-month-old wild-type and VSMC TG2KO male mice were implanted with deoxycorticosterone (DOCA; 50 mg, 21-day releasing pellets) and 1 % salt added to the drinking water. Systolic blood pressure was assessed by tail-cuff method prior to sacrifice. Ex vivo aortic stiffness was determined by atomic force microscopy. Student t-test or two-way ANOVA were used for statistical analysis as appropriate. The results were considered significant when p<0.05. Three to six mice were included per treatment group. Results: administration of DOCA/salt induced increases in systolic blood pressure, augmented expression of TG2 in aorta, as well as increased aortic stiffness in wild-type mice (10.47±1.27kPA DOCA/salt vs. 3.91 + 1.01 kPa placebo). The VSMCTG2KO model exhibited 77% downregulation of TG2 expression in VSMC. VSMC TG2 KO suppressed DOCA/salt induced TG2 activity (29.13 + 2.22 arbitrary units (AU) in DOCA/salt vs 14.10 + 2.90 AU in KO cohort). This was accompanied by a significant improvement in DOCA/ salt-induced hypertension (SBP 142 ± 5.4 mmHg in DOCA/salt treated mice vs. 111.8 ± 6.2 mmHg in VSMCTG2KO). Conclusions: Our data demonstrate for the first-time the key role of TG2 activation in VSMC, in the regulation of hypertensive responses in in a male rodent model of RAAS activation.

Cell-To-Cell Communication in the Resistance Vasculature.

The arterial vasculature can be divided into large conduit arteries, intermediate contractile arteries, resistance arteries, arterioles, and capillaries. Resistance arteries and arterioles primarily function to control systemic blood pressure. The resistance arteries are composed of a layer of endothelial cells oriented parallel to the direction of blood flow, which are separated by a matrix layer termed the internal elastic lamina from several layers of smooth muscle cells oriented perpendicular to the direction of blood flow. Cells within the vessel walls communicate in a homocellular and heterocellular fashion to govern luminal diameter, arterial resistance, and blood pressure. At rest, potassium currents govern the basal state of endothelial and smooth muscle cells. Multiple stimuli can elicit rises in intracellular calcium levels in either endothelial cells or smooth muscle cells, sourced from intracellular stores such as the endoplasmic reticulum or the extracellular space. In general, activation of endothelial cells results in the production of a vasodilatory signal, usually in the form of nitric oxide or endothelial-derived hyperpolarization. Conversely, activation of smooth muscle cells results in a vasoconstriction response through smooth muscle cell contraction. © 2022 American Physiological Society. Compr Physiol 12: 1-35, 2022.

A three-dimensional culture system for generating cardiac spheroids composed of cardiomyocytes, endothelial cells, smooth-muscle cells, and cardiac fibroblasts derived from human induced-pluripotent stem cells.

Cardiomyocytes (CMs), endothelial cells (ECs), smooth-muscle cells (SMCs), and cardiac fibroblasts (CFs) differentiated from human induced-pluripotent stem cells (hiPSCs) are the fundamental components of cell-based regenerative myocardial therapy and can be used as in-vitro models for mechanistic studies and drug testing. However, newly differentiated hiPSC-CMs tend to more closely resemble fetal CMs than the mature CMs of adult hearts, and current techniques for improving CM maturation can be both complex and labor-intensive. Thus, the production of CMs for commercial and industrial applications will require more elementary methods for promoting CM maturity. CMs tend to develop a more mature phenotype when cultured as spheroids in a three-dimensional (3D) environment, rather than as two-dimensional monolayers, and the activity of ECs, SMCs, and CFs promote both CM maturation and electrical activity. Here, we introduce a simple and reproducible 3D-culture–based process for generating spheroids containing all four cardiac-cell types (i.e., cardiac spheroids) that is compatible with a wide range of applications and research equipment. Subsequent experiments demonstrated that the inclusion of vascular cells and CFs was associated with an increase in spheroid size, a decline in apoptosis, an improvement in sarcomere maturation and a change in CM bioenergetics.

Epinephrine evokes shortening of human airway smooth muscle cells following β2 adrenergic receptor desensitization.

Epinephrine (EPI), an endogenous catecholamine involved in the body’s fight-or-flight responses to stress, activates α1-adrenergic receptors (α1ARs) expressed on various organs to evoke a wide range of physiological functions, including vasoconstriction. In the smooth muscle of human bronchi, however, the functional role of EPI on α1ARs remains controversial. Classically, evidence suggests that EPI promotes bronchodilation by stimulating β2-adrenergic receptors (β2ARs). Conventionally, the selective β2AR agonism of EPI was thought to be, in part, due to a predominance of β2ARs and/or a sparse, or lack of α1AR activity in human airway smooth muscle (HASM) cells. Surprisingly, we find that HASM cells express a high abundance of ADRA1B (the α1AR subtype B) and identify a spontaneous “switch-like” activation of α1ARs that evokes intracellular calcium, myosin light chain phosphorylation, and HASM cell shortening. The switch-like responses, and related EPI-induced biochemical and mechanical signals, emerged upon pharmacological inhibition of β2ARs and/or under experimental conditions that induce β2AR tachyphylaxis. EPI-induced procontractile effects were abrogated by an α1AR antagonist, doxazosin mesylate (DM). These data collectively uncover a previously unrecognized feed-forward mechanism driving bronchospasm via two distinct classes of G protein-coupled receptors (GPCRs) and provide a basis for reexamining α1AR inhibition for the management of stress/exercise-induced asthma and/or β2-agonist insensitivity in patients with difficult-to-control, disease subtypes.

Novel purine analogues regulate IL-1β release via inhibition of JAK activity in human aortic smooth muscle cells

Purine analogues bearing a nitrate ester motif were previously discovered as cardioprotective and anti-inflammatory agents, but the anti-inflammatory mechanism remains to be established. We therefore investigated the anti-inflammatory effect of two purine analogues, MK118 bearing a nitrate ester moiety and the methyl-substituted analogue MK196 in Aortic Smooth Muscle Cells (AoSMCs), with emphasis on IL-1β release. The AoSMCs were stimulated with LPS with or without purine analogue, followed by ELISA, Olink proteomics, Western blot and real time PCR of NLRP3 inflammasome components. Both purine analogues inhibited the release of proteins involved in inflammation, such as TRAIL, CCL4, CSF1 and IL-1β in AoSMCs, as well as intracellular gene and protein expression of IL-1β and NLRP3 inflammasome components. MK196, but not MK118, also inhibited the LPS-induced release of IL-7, CXCL10, PD-L1, FLT3L and CCL20. We also showed that MK118 and possibly MK196 act via inhibition of JAKs. In silico studies showed that the purine moiety is a competent hinge binding motif and that the purine-piperazine scaffold is well accommodated in the lipophilic groove of JAK1-3. Both compounds establish interactions with catalytic amino acids in the active site of JAK1-3 and the terminal nitrate ester of MK118 was revealed as a promising pharmacophore.Our data suggest that MK118 and MK196 inhibit the release of proinflammatory proteins in AoSMCs, and targets JAK1-3 activation. Purine analogues also inhibit the expression of NLRP3 inflammasome genes and proteins and may in the future be evaluated for anti-inflammatory aspects on inflammatory diseases.

Retraction Statement.

Retraction Statement.

A TRPC3/6 Channel Inhibitor Promotes Arteriogenesis after Hind-Limb Ischemia.

Retarded revascularization after progressive occlusion of large conductance arteries is a major cause of bad prognosis for peripheral artery disease (PAD). However, pharmacological treatment for PAD is still limited. We previously reported that suppression of transient receptor potential canonical (TRPC) 6 channel activity in vascular smooth muscle cells (VSMCs) facilitates VSMC differentiation without affecting proliferation and migration. In this study, we found that 1-benzilpiperadine derivative (1-BP), a selective inhibitor for TRPC3 and TRPC6 channel activities, induced VSMC differentiation. 1-BP-treated mice showed increased capillary arterialization and improvement of peripheral circulation and skeletal muscle mass after hind-limb ischemia (HLI) in mice. 1-BP had no additive effect on the facilitation of blood flow recovery after HLI in TRPC6-deficient mice, suggesting that suppression of TRPC6 underlies facilitation of the blood flow recovery by 1-BP. 1-BP also improved vascular nitric oxide bioavailability and blood flow recovery after HLI in hypercholesterolemic mice with endothelial dysfunction, suggesting the retrograde interaction from VSMCs to endothelium. These results suggest that 1-BP becomes a potential seed for PAD treatments that target vascular TRPC6 channels.

Functionally linked potassium channel activity in cerebral endothelial and smooth muscle cells is compromised in Alzheimer’s disease

The brain microcirculation is increasingly viewed as a potential target for disease-modifying drugs in the treatment of Alzheimer's disease patients, reflecting a growing appreciation of evidence that cerebral blood flow is compromised in such patients. However, the pathogenic mechanisms in brain resistance arteries underlying blood flow defects have not yet been elucidated. Here we probed the roles of principal vasodilatory pathways in cerebral arteries using the APP23 mouse model of Alzheimer's disease, in which amyloid precursor protein is increased approximately sevenfold, leading to neuritic plaques and cerebrovascular accumulation of amyloid-β similar to those in patients with Alzheimer's disease. Pial arteries from APP23 mice (18 mo old) exhibited enhanced pressure-induced (myogenic) constriction because of a profound reduction in ryanodine receptor-mediated, local calcium-release events ("Ca2+ sparks") in arterial smooth muscle cells and a consequent decrease in the activity of large-conductance Ca2+-activated K+ (BK) channels. The ability of the endothelial cell inward rectifier K+ (Kir2.1) channel to cause dilation was also compromised. Acute application of amyloid-β 1-40 peptide to cerebral arteries from wild-type mice partially recapitulated the BK dysfunction seen in APP23 mice but had no effect on Kir2.1 function. If mirrored in human Alzheimer's disease, these tandem defects in K+ channel-mediated vasodilation could account for the clinical cerebrovascular presentation seen in patients: reduced blood flow and crippled functional hyperemia. These data direct future research toward approaches that reverse this dual vascular channel dysfunction, with the ultimate aim of restoring healthy cerebral blood flow and improving clinical outcomes.

MORPHOFUNCTIONAL ABNORMALITIES WITHIN THE AORTA AS A PREDICTOR OF ARTERIAL HYPERTENSION IN METABOLIC SYNDROME

Objective: Arterial hypertension is an important component of the metabolic syndrome, the development of which is caused by the occurrence of endothelial dysfunction and impaired contractile activity of vascular smooth muscle cells. In the presented work, the morphological basis of an increase in blood pressure under the influence of a high-fat high-carbohydrate diet in rats was investigated. Design and method: A study was carried out in male Wistar rats weighing 250–320 g, 140 days old at the end of research. The rats from the control group were fed standard rat chow. The rats from the experimental group had a high-fat high-carbohydrate diet (proteins 16%, fats 21%, carbohydrates 46%, including 17% fructose, 0.125% cholesterol, 90 days). Body weight, blood pressure were assessed. It was determined the morphological changes in the aortic wall. Mechanical tension of isolated aortic rings was measured by Myobath Tissue Bath System II. Sections of aorta were stained with hematoxylin and eosin, sudan III. Results: It was found that blood pressure increases in animals kept on a high-carbohydrate high-fat diet. The high-carbohydrate high-fat diet causes endothelial vascular dysfunction, impaired contractile activity of vascular smooth muscles. In the rats the experimental group a changes in the activity of calcium and potassium channels, Na +, K +, 2Cl - cotransporter and chlorine conductivity was found. In the aortic wall of the animals of the experimental group, there are signs of elastolysis (initial remodeling of the media), accumulation of lipids in the interstitial cells of the media, hyperplasia of fat cells in the adventitia. Conclusions: Functional and morphological abnormalities in the vascular wall in metabolic syndrome can be the basis for an increase in blood pressure and arterial hypertension.

Targeting PCSK9 Ameliorates Graft Vascular Disease in Mice by Inhibiting NLRP3 Inflammasome Activation in Vascular Smooth Muscle Cells.

BackgroundGraft vascular disease (GVD), which limits the long-term survival of patients after solid-organ transplantation, is associated with both immune responses and nonimmune factors, including dyslipidemia. Recent studies have shown that inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9), a U.S. Federal Drug Administration-approved treatment for hyperlipidemia, reduces cardiovascular events, regulates inflammatory responses, and enhances the efficacy of immune checkpoint therapy in cancer treatment through a cholesterol-independent mechanism. However, whether targeting PCSK9 is a potential therapeutic strategy for GVD remains unknown.MethodsSerum samples and grafts were harvested from male mice undergoing abdominal aortic transplantation. The pathological alterations in the aortic grafts were detected by hematoxylin and eosin staining, Verhoeff’s Van Gieson staining, and Masson staining. Inflammatory cell infiltration and proinflammatory cytokine expression in the aortic grafts were detected by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. The regulatory effects of PCSK9 on vascular smooth muscle cell (VSMC) migration and proliferation were examined by transwell, EdU, and western blot assays. The effect of Evolocumab, a PCSK9 inhibitor, on GVD in humanized PCSK9 mice was also evaluated.ResultsPCSK9 was upregulated in the serum, grafts, and liver of mice in the allograft group subjected to abdominal aortic transplantation. Pcsk9 knockout significantly reduced vascular stenosis, the intimal hyperplasia area and collagen deposition. Pcsk9 depletion also inhibited macrophage recruitment and the mRNA expression of proinflammatory cytokines in aortic grafts. Furthermore, Pcsk9 knockout suppressed the migration and proliferation of VSMCs, which was related to the inhibition of NLRP3 inflammasome activation. Meanwhile, Evolocumab significantly ameliorated GVD in humanized PCSK9 mice.ConclusionPCSK9 is upregulated in a mouse model of GVD, and Pcsk9 knockout reduces vascular occlusion, suggesting that PCSK9 may be a promising target for the treatment of GVD.

CircRNA-miRNA interactions in atherogenesis.

Atherosclerosis is the major cause of coronary artery disease (CAD) which includes unstable angina, myocardial infarction, and heart failure. The onset of atherogenesis, a process of atherosclerotic lesion formation in the intima of arteries, is driven by lipid accumulation, a vicious cycle of reactive oxygen species (ROS)-induced oxidative stress and inflammatory reactions leading to endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) activation, and foam cell formation which further fuel plaque formation and destabilization. In recent years, there is a surge in the number of publications reporting the involvement of circular RNAs (circRNAs) in the pathogenesis of cardiovascular diseases, cancers, and metabolic syndromes. These studies have advanced our understanding on the biological functions of circRNAs. One of the most common mechanism of action of circRNAs reported is the sponging of microRNAs (miRNAs) by binding to the miRNAs response element (MRE), thereby indirectly increases the transcription of their target messenger RNAs (mRNAs). Individual networks of circRNA-miRNA-mRNA associated with atherogenesis have been extensively reported, however, there is a need to connect these findings for a complete overview. This review aims to provide an update on atherogenesis-related circRNAs and analyze the circRNA-miRNA-mRNA interactions in atherogenesis. The atherogenic mechanisms and clinical relevance of each atherogenesis-related circRNA were systematically discussed for better understanding of the knowledge gap in this area.

FRET Visualization of Cyclic Stretch-Activated ERK via Calcium Channels Mechanosensation While Not Integrin β1 in Airway Smooth Muscle Cells.

Mechanical stretch is one type of common physiological activities such as during heart beating, lung breathing, blood flow through the vessels, and physical exercise. The mechanical stimulations regulate cellular functions and maintain body homeostasis. It still remains to further characterize the mechanical-biomechanical coupling mechanism. Here we applied fluorescence resonance energy transfer (FRET) technology to visualize ERK activity in airway smooth muscle (ASM) cells under cyclic stretch stimulation in airway smooth muscle (ASM) cells, and studied the mechanosensing pathway. FRET measurements showed apparent ERK activation by mechanical stretch, which was abolished by ERK inhibitor PD98059 pretreatment. Inhibition of extracellular Ca2+ influx reduced ERK activation, and selective inhibition of inositol 1,4,5-trisphosphate receptor (IP3R) Ca2+ channel or SERCA Ca2+ pump on endoplasmic reticulum (ER) blocked the activation. Chemical inhibition of the L-type or store-operated Ca2+ channels on plasma membrane, or inhibition of integrin β1 with siRNA had little effect on ERK activation. Disruption of actin cytoskeleton but not microtubule one inhibited the stretch-induced ERK activation. Furthermore, the ER IP3R-dependent ERK activation was not dependent on phospholipase C-IP3 signal, indicating possibly more mechanical mechanism for IP3R activation. It is concluded from our study that the mechanical stretch activated intracellular ERK signal in ASM cells through membrane Ca2+ channels mechanosensation but not integrin β1, which was mediated by actin cytoskeleton.

Abstract 532: Dioxin Modifies The Transcriptomic And Epigenetic Landscape Of Smooth Muscle Cells Leading To Adverse Remodeling Of Atherosclerosis

Background: Environmental exposure to dioxin, an active component of cigarette smoke and air pollution has been linked to increased myocardial infarction. Smooth muscle cells (SMC) in the coronary vasculature play a critical role in atherosclerotic plaque remodeling due to their phenotypic plasticity. We have previously found strong dioxin response element activity in modulated SMC of atherosclerotic lesion. In this study, we aimed to understand the effect of dioxin on vascular SMC and atherosclerosis phenotype. Methods: Primary human coronary artery SMC (HCASMC) treated in culture with 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) or vehicle control were used to perform RNA-Seq and ATAC-Seq. ChIP-Seq was performed with antibodies against Aryl-hydrocarbon receptor (AHR) and TCF21. Tamoxifen inducible SMC-lineage tracing reporter mice were used to assess the in-vivo effect of TCDD on aortic SMC. After 8 weeks of high fat diet (HFD), followed by 8 weeks of TCDD injection and HFD, the aortic sinus was collected for histology and single-cell sequencing (10X Genomics). Results: Analysis of the RNA-Seq from TCDD treated HCASMC showed differential enrichment of pathways related to cell migration and vascular development. Further, ATAC-Seq data showed a significant enrichment for pathways regulating vascular development, cell migration, and apoptosis. There was an overall increase in chromatin accessibility suggesting transcriptional activation with TCDD. We observed enrichment for AHR ChIP-Seq peaks in the open chromatin regions along with a significant reciprocal reduction in TCF21 occupancy. The scRNA-Seq of mice treated with TCDD exposure showed differential gene expression of SMC-lineage cells enriching for extracellular matrix (ECM) organization, inflammation, unfolded protein response, and apoptotic process, and histological analysis of the aortic sinus showed increased lesion area with increased presence of SMC-lineage cells and Cd68 + cells compared to control. Conclusion: Dioxin adversely remodels atherosclerotic plaque affecting pathways of ECM organization, inflammation and unfolded protein response in SMC, partly by modifying chromatin accessibility and occupancy of key transcription factors of phenotypic modulation.

Basal Vascular Smooth Muscle Cell Tone in eNOS Knockout Mice Can Be Reversed by Cyclic Stretch and Is Independent of Age.

Introduction and Aims: Endothelial nitric oxide synthase (eNOS) knockout mice develop pronounced cardiovascular disease. In the present study, we describe the alterations in aortic physiology and biomechanics of eNOS knockout and C57Bl/6 control mice at 2–12 months of age, including a thorough physiological investigation of age and cyclic stretch-dependent VSMC contractility and aortic stiffness. Methods and Results: Peripheral blood pressure and aortic pulse wave velocity were measured in vivo, and aortic biomechanical studies and isometric contractions were investigated ex vivo. Age-dependent progression of aortic stiffness, peripheral hypertension, and aortic contractility in eNOS knockout mice was absent, attenuated, or similar to C57Bl/6 control mice. Voltage-gated calcium channel (VGCC)-dependent calcium influx inversely affected isometric contraction and aortic stiffening by α1-adrenergic stimulation in eNOS knockout mice. Baseline aortic stiffness was selectively reduced in eNOS knockout mice after ex vivo cyclic stretch exposure in an amplitude-dependent manner, which prompted us to investigate cyclic stretch dependent regulation of aortic contractility and stiffness. Aortic stiffness, both in baseline conditions and after activation of vascular smooth muscle cell (VSMC) contraction, was reduced with increasing cyclic stretch amplitude. This cyclic stretch dependency was attenuated with age, although aged eNOS knockout mice displayed better preservation of cyclic stretch-dependency compared to C57Bl/6 control mice. Store operated calcium entry-medicated aortic stiffening as induced by inhibiting sarcoplasmic reticulum calcium ATPase pumps with 10 µM CPA was most pronounced in the aorta of aged mice and at low cyclic stretch amplitude, but independent of eNOS. Basal aortic tonus and VSMC depolarization were highly dependent on eNOS, and were most pronounced at low cyclic stretch, with attenuation at increasing cyclic stretch amplitude. Conclusion: eNOS knockout mice display attenuated progression of arterial disease as compared to C57Bl/6 control mice. Basal VSMC tone in eNOS knockout mice could be reduced by ex vivo exposure to cyclic stretch through stretch-dependent regulation of cytosolic calcium. Both baseline and active aortic stiffness were highly dependent on cyclic stretch regulation, which was more pronounced in young versus aged mice. Other mediators of VSMC contraction and calcium handling were dependent on cyclic stretch mechanotransduction, but independent of eNOS.