Coronary Artery Smooth Muscle Cells Research Articles

Intralesional pentraxin 3 increases with atherosclerotic disease progression, but may protect from thrombosis: Friend or foe?

AimTo investigate the role of pentraxin 3 (PTX3) in atherosclerotic disease progression and plaque destabilization, as well as in coronary restenosis after directional coronary atherectomy (DCA). Materials and methodsPTX3 contents of early and advanced atherosclerotic lesions of the aorta obtained at autopsy were determined by ELISA and Western blot. Also, coronary plaques of patients with acute coronary syndrome (ACS) or stable angina pectoris (SAP) obtained by DCA were analyzed by immunohistochemistry for PTX3. The effects of PTX3 on smooth muscle cells (SMCs) and thrombogenesis were investigated with cultured human coronary artery SMCs and a flow chamber system, respectively. ResultsAdvanced atherosclerotic lesions contained a significantly larger amount of PTX3 than early lesions (ELISA: 9.96 ± 2.77 ng/100 mg tissue, n = 8 vs 0.24 ± 0.18 ng/100 mg tissue, n = 6, P = 0.0097). Also, ACS plaques contained a significantly larger amount of PTX3 than SAP plaques (PTX3 immunohistochemistry–positive area percentage: 2.88 ± 0.53 %, n = 22 vs 0.67 ± 0.27 %, n = 23, P = 0.0009). Curiously, the patients who would remain free of post-DCA restenosis (n = 19) had plaques with a significantly higher PTX3 immunohistochemistry–positive area percentage than those who would develop restenosis (n = 12) (2.32 ± 0.49 % vs 0.49 ± 0.17 %, P = 0.002). In the mechanistic part of the study, PTX3 inhibited SMC proliferation and migration. PTX3 also inhibited platelet thrombus formation in the condition simulating arterial blood flow. ConclusionsPTX3 is increased in advanced (vs early) atherosclerotic lesions and unstable (vs stable) coronary plaques. The inhibitory effects of PTX3 on SMCs and thrombogenesis suggest that intraplaque PTX3 might have atheroprotective effects.

Pulmonary Hypertension Induces Serotonin Hyperreactivity and Metabolic Reprogramming in Coronary Arteries via NOX1/4-TRPM2 Signaling Pathway.

Clinical evidence revealed abnormal prevalence of coronary artery (CA) disease in patients with pulmonary hypertension (PH). The mechanistic connection between PH and CA disease is unclear. Serotonin (5-hydroxytryptamine), reactive oxygen species, and Ca2+ signaling have been implicated in both PH and CA disease. Our recent study indicates that NOXs (NADPH [nicotinamide adenine dinucleotide phosphate] oxidases) and TRPM2 (transient receptor potential cation channel subfamily M member 2) are key components of their interplay. We hypothesize that activation of the NOX-TRPM2 pathway facilitates the remodeling of CA in PH. Left and right CAs from chronic hypoxia and monocrotaline-induced PH rats were collected to study vascular reactivity, gene expression, metabolism, and mitochondrial function. Inhibitors or specific siRNA were used to examine the pathological functions of NOX1/4-TRPM2 in CA smooth muscle cells. Significant CA remodeling and 5-hydroxytryptamine hyperreactivity in the right CA were observed in PH rats. NOX1/4-mediated reactive oxygen species production coupled with TRPM2-mediated Ca2+ influx contributed to 5-hydroxytryptamine hyperresponsiveness. CA smooth muscle cells from chronic hypoxia-PH rats exhibited increased proliferation, migration, apoptosis, and metabolic reprogramming in an NOX1/4-TRPM2-dependent manner. Furthermore, the NOX1/4-TRPM2 pathway participated in mitochondrial dysfunction, involving mitochondrial DNA damage, reactive oxygen species production, elevated mitochondrial membrane potential, mitochondrial Ca2+ accumulation, and mitochondrial fission. In vivo knockdown of NOX1/4 alleviated PH and suppressed CA remodeling in chronic hypoxia rats. PH triggers an increase in 5-hydroxytryptamine reactivity in the right CA and provokes metabolic reprogramming and mitochondrial disruption in CA smooth muscle cells via NOX1/4-TRPM2 activation. This signaling pathway may play an important role in CA remodeling and CA disease in PH.

Phosphoglycerate Dehydrogenase Overexpression Inhibits Ferroptosis to Repress Calcification of Human Coronary Artery Vascular Smooth Muscle Cells via the P53/SLC7A11 Pathway.

Coronary artery calcification (CAC) is in almost all patients with coronary artery disease and requires more effective therapies. We aim to explore the effects of phosphoglycerate dehydrogenase (PHGDH) on CAC. We identified the differentially expressed genes through bioinformatic analysis and selected PHGDH for further verification. Human coronary artery smooth muscle cells (HCASMCs) cultured with calcifying medium were used as models of CAC in vitro. Erastin was administered to induce ferroptosis. We determined the cell viability by the cell count kit-8 assay. The alkaline phosphatase activity, calcium content, and the expression of glutathione were evaluated by the corresponding detection kits. The calcification level was detected by alizarin red staining. Then we performed Western blot to examine the expression of runt-related transcription factor 2, bone morphogenetic protein 2, cyclooxygenase 2, glutathione peroxidase 4, P53, and solute carrier family 7a member 11 (SLC7A11). We acquired 201 differentially expressed genes and selected PHGDH to verify. In calcifying medium-induced HCASMCs, PHGDH overexpression increased the cell viability and decreased the alkaline phosphatase activity, calcium content, calcification level, and the expression of bone morphogenetic protein 2 and runt-related transcription factor 2. Additionally, we found higher levels of glutathione, glutathione peroxidase 4, and SLC7A11 and lower levels of cyclooxygenase 2 and P53 after up-regulating PHGDH. Erastin reversed the effects of PHGDH on calcification of HCASMCs. PHGDH overexpression suppresses the calcification level of HCASMCs by inhibiting ferroptosis through the P53/SLC7A11 signaling pathway, suggesting PHGDH as a promising therapeutic target of CAC.

Changes in Potassium Current and BK Channel Protein Expression in Coronary Artery Smooth Muscle Cells of Spontaneously Hypertensive Rats

Changes in Potassium Current and BK Channel Protein Expression in Coronary Artery Smooth Muscle Cells of Spontaneously Hypertensive Rats

Endothelial-derived microvesicles promote pro-migratory cross-talk with smooth muscle cells by a mechanism requiring tissue factor and PAR2 activation.

Microvesicles (MV) released by endothelial cells (EC) following injury or inflammation contain tissue factor (TF) and mediate communication with the underlying smooth muscle cells (SMC). Ser253-phosphorylated TF co-localizes with filamin A at the leading edge of migrating SMC. In this study, the influence of endothelial-derived TF-MV, on human coronary artery SMC (HCASMC) migration was examined. MV derived from human coronary artery EC (HCAEC) expressing TFWt accelerated HCASMC migration, but was lower with cytoplasmic domain-deleted TF. Furthermore, incubation with TFAsp253-MV, or expression of TFAsp253 in HCASMC, reduced cell migration. Blocking TF-factor VIIa (TF-fVIIa) procoagulant/protease activity, or inhibiting PAR2 signaling on HCASMC, abolished the accelerated migration. Incubation with fVIIa alone increased HCASMC migration, but was significantly enhanced on supplementation with TF. Neither recombinant TF alone, factor Xa, nor PAR2-activating peptide (SLIGKV) influenced cell migration. In other experiments, HCASMC were transfected with peptides corresponding to the cytoplasmic domain of TF prior to stimulation with TF-fVIIa. Cell migration was suppressed only when the peptides were phosphorylated at position of Ser253. Expression of mutant forms of filamin A in HCASMC indicated that the enhancement of migration by TF but not by PDGF-BB, was dependent on the presence of repeat-24 within filamin A. Incubation of HCASMC with TFWt-MV significantly reduced the levels of Smoothelin-B protein, and upregulated FAK expression. In conclusion, Ser253-phosphorylated TF and fVIIa released as MV-cargo by EC, act in conjunction with PAR2 on SMC to promote migration and may be crucial for normal arterial homeostasis as well as, during development of vascular disease.

Selenocyanate (SeCN−) acts as an efficient competitive substrate for myeloperoxidase and decreases biological damage induced by hypochlorous acid

The leukocyte-derived enzyme myeloperoxidase (MPO) is a key component of the innate immune response and mediates the killing of pathogens via the generation of the powerful oxidant hypochlorous acid (HOCl). Unintended or excessive formation of this species can however result in damage to host tissues, and this is linked with multiple pathologies associated with acute or chronic inflammation. The active (Compound I) form of MPO is promiscuous and can oxidize multiple alternative anions, in addition to the Cl− used to generate HOCl. These alternative substrates may therefore modulate MPO-mediated HOCl damage. In the current study we examined the hypothesis that selenocyanate (SeCN−), the selenium analogue of thiocyanate (SCN−, a well-established competitive MPO substrate) would inhibit HOCl-mediated damage to human plasma fibronectin (hpFN) or the extracellular matrix laid down by human coronary artery smooth muscle cells. SeCN− modulated HOCl and MPO-mediated damage, in a dose-dependent manner. These data are consistent with SeCN− acting as both a competitive substrate for Compound I of MPO (with IC50 ∼23 μM), and as a direct scavenger of HOCl. Inhibition of protein damage by SeCN− was also detected in the presence of the physiological anions Br−, I− and SCN− at the concentrations typically present in human plasma, consistent with a high affinity of SeCN− for MPO Compound I. In addition, the protective effects of SeCN− and SCN−, as competitive MPO substrates, were additive. Together these data indicate that modest concentrations of SeCN− can, like its sulfur analogue SCN−, act as an effective modulator of inflammation-induced damage.

Induced pluripotent stem cell-derived vascular smooth muscle cells as an in vitro model of coronary spastic angina

Abstract Background Coronary spastic angina (CSA), also known as Prinzmetal’s variant angina, is a form of angina caused by coronary artery spasm. CSA is characterized by enhanced basal tone of coronary artery smooth muscle and hyperreactivity to vasoconstrictor stimuli. The vascular smooth muscle hyperreactivity is likely due to a post-receptorial cellular abnormality in the regulation of myofibril contraction, suggesting the possibility of multiple stimuli acting on various cellular receptors. However, its detailed mechanism is still unclear. To investigate it, various experiments using coronary artery smooth muscle cells obtained from the CSA patients is preferable, but it is impossible to do it clinically and ethically. Purpose The purpose of this study was to establish induced pluripotent stem cell (iPSC)-derived vascular smooth muscle cells (VSMCs) and to characterize this VSMC model for CSA research. Methods Three CSA patients with ST-segment elevation, which is a characteristic of variant angina, were recruited for this study. The isolated skin fibroblasts or peripheral blood mononuclear cells were reprogrammed into iPSCs through electroporation of episomal plasmids encoding the reprogramming genes OCT3/4, SOX2, KLF4, L-MYC, LIN28, and mouse p53DD. We differentiated mesodermal using Glycogen synthase kinase 3 inhibition and Bone morphogenetic protein 4 treatment from iPSCs and resulted in the differentiation of VSMCs by platelet-derived growth factor-BB and Activin A. The differentiation of VSMCs was confirmed by VSMC-specific gene expression in qRT–PCR and fluorescence-activated cell sorting (FACS). We examined biological features and intracellular calcium response to acetylcholine (ACh) in VSMCs obtained from 3 CSA patients and 3 healthy controls. Intracellular free Ca2+ concentration ([Ca2+]i; nM) was measured by fura-2. Results CSA iPSCs were confirmed to have normal karyotypes and pluripotency to differentiate. FACS showed that VSMCs differentiated from iPSCs exhibited smooth muscle cell marker expressions including alpha-smooth muscle actin and SM22-alpha. qRT–PCR showed that VSMCs from iPSCs had expressions of ACTA2 and TAGLN gene similar to the human coronary artery smooth muscle cells. Differentiation induction rate of VSMCs differentiated from iPSCs between CSA and control did not show significant difference. [Ca2+]i at baseline did not differ significantly between them (143 nM in CSA versus 120 nM in control, p=0.63, n=3), but peak increase in [Ca2+]i from baseline after ACh stimulation was significantly increased in CSA group compared with control (372 nM versus 177 nM, p<0.05, n=3). Conclusions iPSC-derived VSMCs obtained from CSA patients showed an enhanced intracellular calcium response to ACh, which is likely responsible for CSA phenotype. Our iPSC-derived VSMC model can be useful for elucidating the mechanism of coronary spasm and developing therapeutic strategy such as drug efficacy.

Abstract 17720: The Role of Soluble Guanylyl Cyclase/NLRP3/RHOA/ROCK Axis in Coronary Artery Spasm: A Potential Biomarker and Therapeutic Target

Background: Coronary artery spasm (CAS) can lead to potentially life-threatening acute coronary syndrome. The second messenger cyclic guanosine 3',5'-monophosphate (cGMP), which is regulated by BNP-pGC-cGMP and nitric oxide (NO)-soluble guanylate cyclase (sGC)-cGMP pathways, regulate not only vasodilation but also the functions of immune cells. However, the significance of sGC, as a primary receptor for NO, is unclear in CAS. Methods: We investigated sGC and downstream signaling in patient monocyte-derived macrophages (PMDMs) and human coronary artery smooth muscle cells (HCASMCs) using computational biology and bioinformatics to correlate macrophage polarization subsets, Lp(a), and inflammasome signaling axes with CAS. Results: Plasma sGC levels were significantly higher in 30 CAS patients compared to 20 non-CAS controls (P<0.001). RNA-sequencing analysis revealed a significant association of sGC expression with NLR Family Pyrin Domain Containing (NLRP)-3 in HCASMCs and induced expression of inflammatory cytokines-specific surface markers. Lp(a) induction promoted the sGC-NLRP3 mediated lipid metabolism axis in PMDMs at both mRNA and protein levels, with elevated M1 polarization. sGC inhibition in HCASMCs reduced RhoA-GTP activity and its downstream effector ROCK, mitigating the Lp(a) effect, while sGC-specific modulator 1-H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-l-one (ODQ) treatment decreased Lp(a)-induced expression of sGC-NLRP3-inflammasome mediators and induced caspase-1, as well as subsequent cleavage of proIL-1β and proIL-18 in VSMCs. Conclusion: sGC/GC molecule in conjunction with the RHOA/ROCK pathway is an early biomarker for CAS. The sGC-NLRP3-inflammasome mediators signaling axis plays an important role in Lp(a)-regulated macrophage polarization and CAS development.

Abstract 12901: ADAR1 RNA Editing in Vascular Smooth Muscle Maintains Vascular Integrity, Regulates Cell State Transition, and is a Novel Mechanism of Coronary Artery Disease Risk

Adenosine-to-inosine (A-to-I) RNA editing is a common RNA modification catalyzed by ADAR (adenosine deaminase acting on RNA) enzymes. ADAR1 serves a crucial function to edit specific immunogenic double stranded RNA (dsRNA) molecules to prevent the dsRNA sensor, MDA5 ( IFIH1 ), activating an interferon stimulated gene (ISG) response. Discoveries in human genetics now implicate deficient ADAR1 RNA editing as a causal mechanism in coronary artery disease (CAD). Here, we reveal in human atherosclerosis, smooth muscle cells (SMCs) express immunogenic dsRNA at markedly higher levels compared to all other cell types. We demonstrate that ADAR1 is the master regulator of RNA editing in primary human coronary artery SMC (HCASMC). Loss of RNA editing through ADAR1 KD in HCASMC causes an ISG response characterized by upregulation of ISG genes (i.e. ISG15, IFI6, IFIH1 ) in addition to genes with known roles in SMC phenotypic transition and CAD risk (i.e. KLF4 , TCF21 , and ZEB2 ). ADAR1 and MDA5 regulate SMC phenotypic modulation and calcification in vitro and in atherosclerosis prone mice. scRNAseq analysis reveals SMC to have increasing ISG expression as cells transition from mature SMC to a more calcified chondromyocyte phenotype. To further evaluate the role for SMC RNA editing in vivo , we generated a conditional SMC specific Adar1 KD mouse ( Adar1 flox/flox , Myh11 CreERT2 , ROSA tdT/+ , ApoE -/- ). At 2 weeks following SMC- Adar1 KD, we observe 50% mortality, where mice demonstrate a severe phenotype of elastin degradation and disarray, intravascular hemorrhage, and inflammatory cell infiltration in the aortic wall. This effect was not seen with an endothelial cell specific deletion model ( Adar1 flox/flox , Cx40 CreERT2 ). scRNAseq of aortic tissue shows that SMC- Adar1 KD causes ISG activation throughout the vessel wall, SMCs show loss of mature SMC markers, and there is robust macrophage and T cell infiltration. Through evaluation of ligand-receptor interaction, we show that Ccl5:Ccr5 is the principal regulator of cell infiltration following SMC- Adar1 KD. Here we provide key evidence to support the observations from human genetics that the ADAR1-dsRNA-MDA5 axis is a causal mechanism in vascular disease and warrants further investigation.

Identification and quantification of protein nitration sites in human coronary artery smooth muscle cells in the absence and presence of peroxynitrous acid/peroxynitrite

Identification and quantification of protein nitration sites in human coronary artery smooth muscle cells in the absence and presence of peroxynitrous acid/peroxynitrite

Inhibition of voltage-dependent K+ channels in rabbit coronary arterial smooth muscle cells by the atypical antipsychotic agent sertindole.

The regulation of membrane potential and the contractility of vascular smooth muscle cells (VSMCs) by voltage-dependent K+ (Kv) potassium channels are well-established. In this study, native VSMCs from rabbit coronary arteries were used to investigate the inhibitory effect of sertindole, an atypical antipsychotic agent, on Kv channels. Sertindole induced dose-dependent inhibition of Kv channels, with an IC50 of 3.13 ± 0.72 μM. Although sertindole did not cause a change in the steady-state activation curve, it did lead to a negative shift in the steady-state inactivation curve. The application of 1- or 2-Hz train pulses failed to alter the sertindole-induced inhibition of Kv channels, suggesting use-independent effects of the drug. The inhibitory response to sertindole was significantly diminished by pretreatment with a Kv1.5 inhibitor but not by Kv2.1 and Kv7 subtype inhibitors. These findings demonstrate the sertindole dose-dependent and use-independent inhibition of vascular Kv channels (mainly the Kv1.5 subtype) through a mechanism that involves altering steady-state inactivation curves. Therefore, the use of sertindole as an antipsychotic drug may have adverse effects on the cardiovascular system.

Non-Psychoactive Phytocannabinoids Inhibit Inflammation-Related Changes of Human Coronary Artery Smooth Muscle and Endothelial Cells.

Atherosclerosis is associated with vascular smooth muscle cell proliferation, chronic vascular inflammation, and leukocyte adhesion. In view of the cardioprotective effects of cannabinoids described in recent years, the present study investigated the impact of the non-psychoactive phytocannabinoids cannabidiol (CBD) and tetrahydrocannabivarin (THCV) on proliferation and migration of human coronary artery smooth muscle cells (HCASMC) and on inflammatory markers in human coronary artery endothelial cells (HCAEC). In HCASMC, CBD and THCV at nontoxic concentrations exhibited inhibitory effects on platelet-derived growth factor-triggered proliferation (CBD) and migration (CBD, THCV). When interleukin (IL)-1β- and lipopolysaccharide (LPS)-stimulated HCAEC were examined, both cannabinoids showed a concentration-dependent decrease in the expression of vascular cell adhesion molecule-1 (VCAM-1), which was mediated independently of classical cannabinoid receptors and was not accompanied by a comparable inhibition of intercellular adhesion molecule-1. Further inhibitor experiments demonstrated that reactive oxygen species, p38 mitogen-activated protein kinase activation, histone deacetylase, and nuclear factor κB (NF-κB) underlie IL-1β- and LPS-induced expression of VCAM-1. In this context, CBD and THCV were shown to inhibit phosphorylation of NF-κB regulators in LPS- but not IL-1β-stimulated HCAEC. Stimulation of HCAEC with IL-1β and LPS was associated with increased adhesion of monocytes, which, however, could not be significantly abolished by CBD and THCV. In summary, the results highlight the potential of the non-psychoactive cannabinoids CBD and THCV to regulate inflammation-related changes in HCASMC and HCAEC. Considering their effect on both cell types studied, further preclinical studies could address the use of CBD and THCV in drug-eluting stents for coronary interventions.

Dipyridamole and vascular healing following stent implantation.

Patients undergoing coronary stent implantation incur a 2% annual rate of adverse events, largely driven by in-stent restenosis (ISR) due to neointimal (NI) tissue proliferation, a process in which smooth muscle cell (SMC) biology may play a central role. Dipyridamole (DP) is an approved therapeutic agent with data supporting improved vascular patency rates. Pre-clinical data supports that DP may enact its vasculoprotective effects via adenosine receptor-A2B (ADOR-A2B). We sought to evaluate the efficacy of DP to mitigate ISR in a pre-clinical rabbit stent model. 24 New Zealand White Rabbits were divided into two cohorts-non-atherosclerosis and atherosclerosis (n = 12/cohort, 6 male and 6 female). Following stent implantation, rabbits were randomized 1:1 to control or oral dipyridamole therapy for 6 weeks followed by optical coherence tomography (OCT) and histology assessment of NI burden and stent strut healing. Compared to control, DP demonstrated a 16.6% relative reduction in NI volume (14.7 ± 0.8% vs. 12.5 ± 0.4%, p = 0.03) and a 36.2% relative increase in optimally healed stent struts (37.8 ± 2.8% vs. 54.6 ± 2.5%, p < 0.0001). Atherosclerosis demonstrated attenuated effect with no difference in NI burden (15.2 ± 1.0% vs. 16.9 ± 0.8%, p = 0.22) and only a 14.2% relative increase in strut healing (68.3 ± 4.1% vs. 78.7 ± 2.5%, p = 0.02). DP treated rabbits had a 44.6% (p = 0.045) relative reduction in NI SMC content. In vitro assessment of DP and coronary artery SMCs yielded dose-dependent reduction in SMC migration and proliferation. Selective small molecule antagonism of ADOR-A2B abrogated the effects of DP on SMC proliferation. DP modulated SMC phenotypic switching with ADOR-A2B siRNA knockdown supporting its role in the observed effects. Dipyridamole reduces NI proliferation and improves stent healing in a preclinical model of stent implantation with conventional antiplatelets. Atherosclerosis attenuates the observed effect. Clinical trials of DP as an adjunctive agent may be warranted to evaluate for clinical efficacy in stent outcomes.

Lurasidone blocks the voltage-gated potassium channels of coronary arterial smooth muscle cells

Lurasidone is a second-generation antipsychotic drug used to treat schizophrenia, mania, and bipolar disorder. The drug is an antagonist of the 5-HT2A and D2 receptors. No effect of lurasidone on the voltage-gated K+ (Kv) channels has yet been identified. Here, we show that lurasidone inhibits the vascular Kv channels of rabbit coronary arterial smooth muscle cells in a dose-dependent manner with an IC50 of 1.88 ± 0.21 μM and a Hill coefficient of 0.98 ± 0.09. Although lurasidone (3 μM) did not affect the activation kinetics, the drug negatively shifted the inactivation curve, suggesting that the drug interacted with the voltage sensors of Kv channels. Application of 1 or 2 Hz train steps in the presence of lurasidone significantly increased Kv current inhibition. The recovery time after channel inactivation increased in the presence of lurasidone. These results suggest that the inhibitory action of lurasidone is use (state)-dependent. Pretreatment with a Kv 1.5 subtype inhibitor effectively reduced the inhibitory effect of lurasidone. However, the inhibitory effect on Kv channels did not markedly change after pretreatment with a Kv 2.1 or a Kv7 subtype inhibitor. In summary, lurasidone inhibits vascular Kv channels (primarily the Kv1.5 subtype) in a concentration- and use (state)-dependent manner by shifting the steady-state inactivation curve.

The angiogenic neuropeptide catestatin exerts beneficial effects on human coronary vascular cells and cardiomyocytes

IntroductionMyocardial infarction (MI) induces irreversible tissue damage, eventually leading to heart failure. Exogenous induction of angiogenesis positively influences ventricular remodeling after MI. Recently, we could show that therapeutic angiogenesis by the neuropeptide catestatin (CST) restores perfusion in the mouse hind limb ischemia model by the induction of angio-, arterio- and vasculogenesis. Thus, we assumed that CST might exert beneficial effects on cardiac cells. Methods/resultsTo test the effect of CST on cardiac angiogenesis in-vitro matrigel assays with human coronary artery endothelial cells (HCAEC) were performed. CST significantly mediated capillary like tube formation comparable to vascular endothelial growth factor (VEGF), which was used as positive control. Interestingly, blockade of bFGF resulted in abrogation of observed effects. Moreover, CST induced proliferation of HCAEC and human coronary artery smooth muscle cells (HCASMC) as determined by BrdU-incorporation. Similar to the matrigel assay blockade of bFGF attenuated the effect. Consistent with these findings western blot assays revealed a bFGF-dependent phosphorylation of extracellular-signal regulated kinase (ERK) 1/2 by CST in these cell lines. Finally, CST protected human cardiomyocytes in-vitro from apoptosis. ConclusionCST might qualify as potential candidate for therapeutic angiogenesis in MI.

Inhibition of voltage-dependent K+ currents of rabbit coronary arterial smooth muscle cells by the atypical antipsychotic paliperidone.

Paliperidone, an atypical antipsychotic, is widely used to treat schizophrenia. In this study, we explored whether paliperidone inhibited the voltage-dependent K+ (Kv) channels of rabbit coronary arterial smooth muscle cells. Paliperidone reduced Kv channel activity in a concentration-dependent manner with a half-maximal inhibitory concentration (IC50 ) of 16.58 ± 3.03 μM and a Hill coefficient of 0.60 ±0.04. It did not significantly shift the steady-state activation or inactivation curves, suggesting that the drug did not affect the gating properties of Kv channels. In the presence of paliperidone, the application of 20 repetitive depolarizing pulses at 1 and 2Hz gradually increased the inhibition of the Kv current. Further, the recovery time constant after Kv channel inactivation was increased by paliperidone, indicating that it inhibited the Kv channel in a use (state)-dependent manner. Its inhibitory effects were reduced by pretreatment with a Kv1.5 subtype inhibitor. However, pretreatment with a Kv2.1 or Kv7 inhibitor did not reduce its inhibitory effect. We conclude that paliperidone inhibits Kv channels (mainly Kv1.5 subtype channels) in a concentration- and use (state)-dependent manner without changing channel gating.

Abstract P3043: Mir92b-3p: A Key Regulator In Vascular Homeostasis And Remodelling

In vascular disease, cells undergo important alterations in cellular function, influencing vascular homeostasis. Apoptosis is one of these functions, affecting vascular tone and plaque stability. Influencing this process for example, by targeting microRNAs is key for therapeutic strategies tackling vascular diseases in a cell-specific manner. We identified the critical role of miR92b-3p on the functional properties of vascular cells. Studying human primary coronary artery smooth muscle cells (SMCs) and human umbilical vein endothelial cells (ECs), methods included expression analysis in mice tissue after restenosis by wire-induced injury and in atherosclerosis. The role of miR-92b on cellular function and target regulation was determined by pre- and antagomir transfection. Initial analysis in vivo showed miR92b-3p to be significantly upregulated in atherosclerosis (p&lt;0,01) and regulated in restenosis (p&lt;0,05). Under growth conditions in both ECs and SMCs, miR-92b-3p was significantly higher expressed (p&lt;0,05). In SMCs, upregulation of miR92b-3p resulted in increased proliferation (p&lt;0,01) and significantly enhanced cell migration in SMCs (p&lt;0,001) but hampered migration in ECs (p&lt;0,01). Downregulation of miR-92b-3p in SMC resulted in decreased migrational (p&lt;0.001) and proliferative capacity (p&lt;0.001), accompanied by a reduction in metabolic activity (p&lt;0.05) and, exclusively in SMCs, increased apoptosis (p&lt;0.05). In ECs, proliferation was enhanced following downregulation (p&lt;0,01). Multiple targets were identified, using Western blot and qPCR including KLF4 (p&lt;0,01), DKK3 (p&lt;0,05), Notch1 (p&lt;0,01), PTEN (p&lt;0,05), and especially in SMC, Bim (p&lt;0,001). Regulation of Bim by miR92b-3p and subsequent apoptosis was then evaluated by siRNA-knockdown experiments, confirming their strong interaction. We further verified the crucial role of miR-92b-3p by reversing cell death in apoptotic SMCs through miR-92b-3p overexpression experiments (p&lt;0.05). This study reports miR 92b-3p to be a crucial regulator of vascular function. Therapeutic regulation might present a promising strategy for stabilizing critical plaques, restoring the function of vascular cells, and thereby preventing vascular remodeling.

Modification of histones by the myeloperoxidase-derived oxidant hypochlorous acid (HOCl) alters their reactivity with vascular smooth muscle cells

In the nucleus, histones are essential in the packaging of DNA and the regulation of gene expression. These histones can also be released to the extracellular space by mechanisms such as necrosis and neutrophil extracellular trap (NET) formation. Histones are cytotoxic and cause sterile inflammation, and as a result, have been implicated in tissue damage in several pathologies, including atherosclerosis. Myeloperoxidase (MPO) is also present on NETs, which is catalytically active and able to produce hypochlorous acid (HOCl). This could modify histones and alter their extracellular reactivity. In this study, we compared the reactivity of histones with and without modification by HOCl with primary human coronary artery smooth muscle cells (HCASMCs). Histones induced a loss in viability and cell death primarily by apoptosis, which was attenuated on modification of the histones by HOCl. Exposure of HCASMCs to histones also resulted in the increased expression of the pro-inflammatory genes monocyte chemoattractant protein-1 (MCP-1), interleukin 6 (IL-6), and vascular cell adhesion molecule-1 (VCAM-1) and a decrease in intracellular thiols. In addition, there were changes in the expression of the stress related gene heme oxygenase-1 (HO-1). Modification of the histones with HOCl had no significant influence on changes in gene expression or thiol loss, in contrast to the cytotoxicity studies. Together, these studies provide new insight into the pathways by which histones could promote vascular dysfunction, which could be relevant to inflammatory diseases, such as atherosclerosis and sepsis, which are associated with elevated NET release and high circulating histones, respectively.

In vitro biological responses of plasma nanocoatings for coronary stent applications.

In-stent restenosis and thrombosis remain to be long-term challenges in coronary stenting procedures. The objective of this study was to evaluate the in vitro biological responses of trimethylsilane (TMS) plasma nanocoatings modified with NH3 /O2 (2:1 molar ratio) plasma post-treatment (TMS + NH3 /O2 nanocoatings) on cobalt chromium (CoCr) alloy L605 coupons, L605 stents, and 316L stainless steel (SS) stents. Surface properties of the plasma nanocoatings with up to 2-year aging time were characterized by wettability assessment and x-ray photoelectron spectroscopy (XPS). It was found that TMS + NH3 /O2 nanocoatings had a surface composition of 41.21 ± 1.06 at% oxygen, 31.90 ± 1.08 at% silicon, and 24.12 ± 1.7 at% carbon, and very small but essential amount of 2.77 ± 0.18 at% nitrogen. Surface chemical stability of the plasma coatings was noted with persistent O/Si atomic ratio of 1.292-1.413 and N/Si atomic ratio of ~0.087 through 2 years. The in vitro biological responses of plasma nanocoatings were studied by evaluating the cell proliferation and migration of porcine coronary artery endothelial cells (PCAECs) and smooth muscle cells (PCASMCs). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay results revealed that, after 7-day incubation, TMS + NH3 /O2 nanocoatings maintained a similar level of PCAEC proliferation while showing a decrease in the viability of PCASMCs by 73 ± 19% as compared with uncoated L605 surfaces. Cell co-culture of PCAECs and PCASMCs results showed that, the cell ratio of PCAEC/PCASMC on TMS + NH3 /O2 nanocoating surfaces was 1.5-fold higher than that on uncoated L605 surfaces, indicating enhanced selectivity for promoting PCAEC growth. Migration test showed comparable PCAEC migration distance for uncoated L605 and TMS + NH3 /O2 nanocoatings. In contrast, PCASMC migration distance was reduced nearly 8.5-fold on TMS + NH3 /O2 nanocoating surfaces as compared to the uncoated L605 surfaces. Platelet adhesion test using porcine whole blood showed lower adhered platelets distribution (by 70 ± 16%), reduced clotting attachment (by 54 ± 12%), and less platelet activation on TMS + NH3 /O2 nanocoating surfaces as compared with the uncoated L605 controls. It was further found that, under shear stress conditions of simulated blood flow, TMS + NH3 /O2 nanocoating significantly inhibited platelet adhesion compared to the uncoated 316L SS stents and TMS nanocoated 316L SS stents. These results indicate that TMS + NH3 /O2 nanocoatings are very promising in preventing both restenosis and thrombosis for coronary stent applications.

Encainide, a class Ic anti-arrhythmic agent, blocks voltage-dependent potassium channels in coronary artery smooth muscle cells.

Voltage-dependent K+ (Kv) channels are widely expressed on vascular smooth muscle cells and regulate vascular tone. Here, we explored the inhibitory effect of encainide, a class Ic anti-arrhythmic agent, on Kv channels of vascular smooth muscle from rabbit coronary arteries. Encainide inhibited Kv channels in a concentration-dependent manner with an IC50 value of 8.91 ± 1.75 μM and Hill coefficient of 0.72 ± 0.06. The application of encainide shifted the activation curve toward a more positive potential without modifying the inactivation curve, suggesting that encainide inhibited Kv channels by altering the gating property of channel activation. The inhibition by encainide was not significantly affected by train pulses (1 and 2 Hz), indicating that the inhibition is not use (state)-dependent. The inhibitory effect of encainide was reduced by pretreatment with the Kv1.5 subtype inhibitor. However, pretreatment with the Kv2.1 subtype inhibitor did not alter the inhibitory effects of encainide on Kv currents. Based on these results, encainide inhibits vascular Kv channels in a concentration-dependent and use (state)-independent manner by altering the voltage sensor of the channels. Furthermore, Kv1.5 is the main Kv subtype involved in the effect of encainide.