MiRNA-132/212 encapsulated by adipose tissue-derived exosomes worsen atherosclerosis progression.

BACKGROUND: Visceral adipose tissue in individuals with obesity is an independent cardiovascular risk indicator. However, it remains unclear whether adipose tissue influences common cardiovascular diseases, such as atherosclerosis, through its secreted exosomes. METHODS: The exosomes secreted by adipose tissue from diet-induced obesity mice were isolated to examine their impact on the progression of atherosclerosis and the associated mechanism. Endothelial apoptosis and the proliferation and migration of vascular smooth muscle cells (VSMCs) within the atherosclerotic plaque were evaluated. Statistical significance was analyzed using GraphPad Prism 9.0 with appropriate statistical tests. RESULTS: We demonstrate that adipose tissue-derived exosomes (AT-EX) exacerbate atherosclerosis progression by promoting endothelial apoptosis, proliferation, and migration of VSMCs within the plaque in vivo. MicroRNA-132/212 (miR-132/212) was detected within AT-EX cargo. Mechanistically, miR-132/212-enriched AT-EX exacerbates palmitate acid-induced endothelial apoptosis via targeting G protein subunit alpha 12 and enhances platelet-derived growth factor type BB-induced VSMC proliferation and migration by targeting phosphatase and tensin homolog in vitro. Importantly, melatonin decreases exosomal miR-132/212 levels, thereby mitigating the pro-atherosclerotic impact of AT-EX. CONCLUSION: These data uncover the pathological mechanism by which adipose tissue-derived exosomes regulate the progression of atherosclerosis and identify miR-132/212 as potential diagnostic and therapeutic targets for atherosclerosis.

Vascular wall microenvironment: exosomes secreted by adventitial fibroblasts induced vascular calcification.

Vascular calcification often occurs in patients with chronic renal failure (CRF), which significantly increases the incidence of cardiovascular events in CRF patients. Our previous studies identified the crosstalk between the endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), and the paracrine effect of VSMCs, which regulate the calcification of VSMCs. Herein, we aim to investigate the effects of exosomes secreted by high phosphorus (HPi) -induced adventitial fibroblasts (AFs) on the calcification of VSMCs and the underlying mechanism, which will further elucidate the important role of AFs in high phosphorus vascular wall microenvironment. The conditioned medium of HPi-induced AFs promotes the calcification of VSMCs, which is partially abrogated by GW4869, a blocker of exosomes biogenesis or release. Exosomes secreted by high phosphorus-induced AFs (AFsHPi-Exos) show similar effects on VSMCs. miR-21-5p is enriched in AFsHPi-Exos, and miR-21-5p enhances osteoblast-like differentiation of VSMCs by downregulating cysteine-rich motor neuron 1 (Crim1) expression. AFsHPi-Exos and exosomes secreted by AFs with overexpression of miR-21-5p (AFsmiR21M-Exos) significantly accelerate vascular calcification in CRF mice. In general, AFsHPi-Exos promote the calcification of VSMCs and vascular calcification by delivering miR-21-5p to VSMCs and subsequently inhibiting the expression of Crim1. Combined with our previous studies, the present experiment supports the theory of vascular wall microenvironment.

Protective role of small extracellular vesicles derived from HUVECs treated with AGEs in diabetic vascular calcification.

The pathogenesis of vascular calcification in diabetic patients remains elusive. As an effective information transmitter, small extracellular vesicles (sEVs) carry abundant microRNAs (miRNAs) that regulate the physiological and pathological states of recipient cells. In the present study, significant up-regulation of miR-126-5p was observed in sEVs isolated from human umbilical vein endothelial cells (HUVECs) stimulated with advanced glycation end-products (A-EC/sEVs). Intriguingly, these sEVs suppressed the osteogenic differentiation of vascular smooth muscle cells (VSMCs) by targeting BMPR1B, which encodes the receptor for BMP, thereby blocking the smad1/5/9 signalling pathway. In addition, knocking down miR-126-5p in HUVECs significantly diminished the anti-calcification effect of A-EC/sEVs in a mouse model of type 2 diabetes. Overall, miR-126-5p is highly enriched in sEVs derived from AGEs stimulated HUVECs and can target BMPR1B to negatively regulate the trans-differentiation of VSMCs both in vitro and in vivo.

Melatonin alleviates vascular calcification and ageing through exosomal miR-204/miR-211 cluster in a paracrine manner.

In the elderly with atherosclerosis, hypertension and diabetes, vascular calcification and ageing are ubiquitous. Melatonin (MT) has been demonstrated to impact the cardiovascular system. In this study, we have shown that MT alleviates vascular calcification and ageing, and the underlying mechanism involved. We found that both osteogenic differentiation and senescence of vascular smooth muscle cells (VSMCs) were attenuated by MT in a MT membrane receptor-dependent manner. Moreover, exosomes isolated from VSMCs or calcifying vascular smooth muscle cells (CVSMCs) treated with MT could be uptaken by VSMCs and attenuated the osteogenic differentiation and senescence of VSMCs or CVSMCs, respectively. Moreover, we used conditional medium from MT-treated VSMCs and Transwell assay to confirm exosomes secreted by MT-treated VSMCs attenuated the osteogenic differentiation and senescence of VSMCs through paracrine mechanism. We also found exosomal miR-204/miR-211 mediated the paracrine effect of exosomes secreted by VSMCs. A potential target of these two miRs was revealed to be BMP2. Furthermore, treatment of MT alleviated vascular calcification and ageing in 5/6-nephrectomy plus high-phosphate diet-treated (5/6 NTP) mice, while these effects were partially reversed by GW4869. Exosomes derived from MT-treated VSMCs were internalised into mouse artery detected by in vivo fluorescence image, and these exosomes reduced vascular calcification and ageing of 5/6 NTP mice, but both effects were largely abolished by inhibition of exosomal miR-204 or miR-211. In summary, our present study revealed that exosomes from MT-treated VSMCs could attenuate vascular calcification and ageing in a paracrine manner through an exosomal miR-204/miR-211.

Percutaneous gallbladder drainage as a bridge to concomitant coronary artery bypass grafting and laparoscopic cholecystectomy.

A 74-year-old woman with left main and three-vessel coronary artery disease was scheduled for off-pump coronary artery bypass grafting and developed acute severe cholecystitis preoperatively. Percutaneous gallbladder drainage was placed to achieve gallbladder decompression and infection control. Two weeks later, CABG and laparoscopic cholecystectomy were successfully performed at the same time.

Mesenchymal stem cell-derived conditioned medium attenuate angiotensin II-induced aortic aneurysm growth by modulating macrophage polarization.

Mesenchymal stem cells (MSCs) exhibit therapeutic benefits on aortic aneurysm (AA); however, the molecular mechanisms are not fully understood. The current study aimed to investigate the therapeutic effects and potential mechanisms of murine bone marrow MSC (BM-MSCs)-derived conditioned medium (MSCs-CM) on angiotensin II (AngII)-induced AA in apolipoprotein E-deficient (apoE-/- ) mice. Murine BM-MSCs, MSCs-CM or control medium were intravenously administrated into AngII-induced AA in apoE-/- mice. Mice were sacrificed at 2 weeks after injection. BM-MSCs and MSCs-CM significantly attenuated matrix metalloproteinase (MMP)-2 and MMP-9 expression, aortic elastin degradation and AA growth at the site of AA. These treatments with BM-MSCs and MSCs-CM also decreased Ly6chigh monocytes in peripheral blood on day 7 and M1 macrophage infiltration in AA tissues on day 14, whereas they increased M2 macrophages. In addition, BM-MSCs and MSCs-CM reduced MCP-1, IL-1Ra and IL-6 expression and increased IL-10 expression in AA tissues. In vitro, peritoneal macrophages were co-cultured with BM-MSCs or fibroblasts as control in a transwell system. The mRNA and protein expression of M2 macrophage markers were evaluated. IL-6 and IL-1ß were reduced, while IL-10 was increased in the BM-MSC systems. The mRNA and protein expression of M2 markers were up-regulated in the BM-MSC systems. Furthermore, high concentration of IGF1, VEGF and TGF-ß1 was detected in MSCs-CM. Our results suggest that MSCs-CM could prevent AA growth potentially through regulating macrophage polarization. These results may provide a new insight into the mechanisms of BM-MSCs in the therapy of AA.

Diverse roles of macrophage polarization in aortic aneurysm: destruction and repair.

Aortic aneurysm (AA) is defined as an enlargement of the aorta greater than 1.5 times its normal size. Early diagnosis of AA is challenging and mortality of AA is high. Curative pharmacological treatments for AA are still lacking, highlighting the need for better understanding of the underlying mechanisms of AA progression. Accumulating studies have proven that the polarization state of circulating monocyte-derived macrophages plays a crucial role in regulating the development of AA. Distinct macrophage subtypes display different functions. Several studies targeting macrophage polarization during AA formation and progression showed potential treatment effects. In this review, we focus on the recent advances of research on macrophage polarization in the progression of AA and propose that targeting macrophage polarization could hold great promise for preventing and treating AA.

Apelin attenuates the osteoblastic differentiation of aortic valve interstitial cells via the ERK and PI3-K/Akt pathways.

Aortic valve calcification (AVC), which used to be recognized as a passive and irreversible process, is now widely accepted as an active and regulated process characterized by osteoblastic differentiation of aortic valve interstitial cells (AVICs). Apelin, the endogenous ligand for G-protein-coupled receptor APJ, was found to have protective cardiovascular effects in several studies. However, the effects and mechanisms of apelin on osteoblastic differentiation of AVICs have not been elucidated. Using a pro-calcific medium, we devised a method to produce calcific human AVICs. These cells were used to study the relationship between apelin and the osteoblastic calcification of AVICs and the involved signaling pathways. Alkaline phosphatase (ALP) activity/expression and runt-related transcription factor 2 (Runx2) expression were examined as hallmark proteins in this research. The involved signaling pathways were studied using the extracellular signal-regulated kinase (ERK) inhibitor, PD98059, and the phosphatidylinositol 3-kinase (PI3-K) inhibitor, LY294002. The results indicate that apelin attenuates the expression and activity of ALP, the expression of Runx2, and the formation of mineralized nodules. This protective effect was dependent on the dose of apelin, reaching the maximum at 100 pM, and was connected to activity of ERK and Akt (a downstream effector of PI3-K). The activation of ERK and PI3-K initiated the effects of apelin on ALP activity/expression and Runx2, but PD98059 and LY294002 abolished the effect. These results demonstrate that apelin attenuates the osteoblastic differentiation of AVICs via the ERK and PI3-K/Akt pathway.

Vascular wall microenvironment: Endothelial cells original exosomes mediated melatonin-suppressed vascular calcification and vascular ageing in a m6A methylation dependent manner.

Vascular calcification and vascular ageing are "silent" diseases but are highly prevalent in patients with end stage renal failure and type 2 diabetes, as well as in the ageing population. Melatonin (MT) has been shown to induce cardiovascular protection effects. However, the role of MT on vascular calcification and ageing has not been well-identified. In this study, the aortic transcriptional landscape revealed clues for MT related cell-to-cell communication between endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in vascular calcification and vascular ageing. Furthermore, we elucidated that it was exosomes that participate in the information transportation from ECs to VSMCs. The exosomes secreted from melatonin-treated ECs (MT-ECs-Exos) inhibited calcification and senescence of VSMCs. Mechanistically, miR-302d-5p was highly enriched in MT-ECs-Exos, while depletion of miR-302d-5p blocked the ability of MT-ECs-Exos to suppress VSMC calcification and senescence. Notably, Wnt3 was a bona fide target of miR-302d-5p and modulated VSMC calcification and senescence. Furthermore, we found that maturation of endothelial derived exosomal miR-302d-5p was promoted by WTAP in an N6-methyladenosine (m6A)-dependent manner. Interestingly, MT alleviated vascular calcification and ageing in 5/6-nephrectomy (5/6 NTP) mice, a chronic kidney disease (CKD) induced vascular calcification and vascular ageing mouse model. MT-ECs-Exos was absorbed by VSMCs in vivo and effectively prevented vascular calcification and ageing in 5/6 NTP mice. ECs-derived miR-302d-5p mediated MT induced anti-calcification and anti-ageing effects in 5/6 NTP mice. Our study suggests that MT-ECs-Exos alleviate vascular calcification and ageing through the miR-302d-5p/Wnt3 signaling pathway, dependent on m6A methylation.

Biofunction and clinical potential of extracellular vesicles from methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus (MRSA), a globally widespread pathogen that is highly resistant to antibiotics, can lead to serious infection, and has fairly limited treatment options. Over decades, extracellular vesicles (EVs) from MRSA have received increasing attention, and their roles in the pathogenesis of MRSA have been well studied. The secretion process of MRSA EVs is complex and regulated by various factors. During this process, EVs carry a variety of bioactive molecules including enzymes, lipoproteins, toxins, DNA, and RNA, which play important roles in antibiotic resistance, cytotoxicity, and immune escape. Biological enzymes and drug resistance genes are important factors for MRSA EVs to promote drug resistance. As the components of EVs are derived from MRSA, these compounds can trigger the immune response of the host, and thus have great potential as a vaccine. These lipid-coated vesicles secreted by MRSA contain a variety of bioactive factors, which are considered as the critical factors affecting the pathogenesis, drug resistance, and colonization of MRSA, and thus have the potential to treat these patients infected with MRSA. However, the clinical application of MRSA EVs as the acellular vaccines is still a long way off, and further research should be encouraged to bridge the gap between theoretical study and practical application.

Changes of ubiquitylated proteins in atrial fibrillation associated with heart valve disease: proteomics in human left atrial appendage tissue.

Background: Correlations between posttranslational modifications and atrial fibrillation (AF) have been demonstrated in recent studies. However, it is still unclear whether and how ubiquitylated proteins relate to AF in the left atrial appendage of patients with AF and valvular heart disease. Methods: Through LC-MS/MS analyses, we performed a study on tissues from eighteen subjects (9 with sinus rhythm and 9 with AF) who underwent cardiac valvular surgery. Specifically, we explored the ubiquitination profiles of left atrial appendage samples. Results: In summary, after the quantification ratios for the upregulated and downregulated ubiquitination cutoff values were set at >1.5 and <1:1.5, respectively, a total of 271 sites in 162 proteins exhibiting upregulated ubiquitination and 467 sites in 156 proteins exhibiting downregulated ubiquitination were identified. The ubiquitylated proteins in the AF samples were enriched in proteins associated with ribosomes, hypertrophic cardiomyopathy (HCM), glycolysis, and endocytosis. Conclusions: Our findings can be used to clarify differences in the ubiquitination levels of ribosome-related and HCM-related proteins, especially titin (TTN) and myosin heavy chain 6 (MYH6), in patients with AF, and therefore, regulating ubiquitination may be a feasible strategy for AF.

Intensive Lipid-Lowering Therapy as per the Latest Dyslipidemia Management Guideline in Predicting Favorable Long-Term Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Grafting: A Retrospective Cohort Study.

Background There are limited data on low-density lipoprotein cholesterol (LDL-C) goal achievement per the 2019 European Society of Cardiology/European Atherosclerosis Society dyslipidemia management guidelines and its impact on long-term outcomes in patients undergoing coronary artery bypass grafting (CABG). We investigated the association between LDL-C levels attained 1 year after CABG and the long-term outcomes. Methods and Results A total of 2072 patients diagnosed with multivessel coronary artery disease and undergoing CABG between 2011 and 2020 were included. Patients were categorized by lipid levels at 1 year after CABG, and the occurrence of major adverse cardiovascular and cerebrovascular events (MACCEs) was evaluated. The goal of LDL-C <1.40 mmol/L was attained in only 310 patients (14.9%). During a mean follow-up of 4.2 years after the index 1-year assessment, 25.0% of the patients experienced MACCEs. Multivariable-adjusted hazard ratios (95% CIs) for MACCEs, cardiac death, nonfatal myocardial infarction, nonfatal stroke, revascularization, and cardiac rehospitalization were 1.94 (1.41-2.67), 2.27 (1.29-3.99), 2.45 (1.55-3.88), 1.17 (0.63-2.21), 2.47 (1.31-4.66), and 1.87 (1.19-2.95), respectively, in patients with LDL-C ≥2.60 mmol/L, compared with patients with LDL-C <1.40 mmol/L. The LDL-C levels at 1-year post-CABG were independently associated with long-term MACCEs. Conclusions This retrospective analysis demonstrates that lipid goals are not attained in the vast majority of patients at 1 year after CABG, which is independently associated with the increased risk of long-term MACCEs. Further prospective, multicenter studies are warranted to validate if intensive lipid management could improve the outcomes of patients undergoing CABG.

Taurine suppresses osteoblastic differentiation of aortic valve interstitial cells induced by beta-glycerophosphate disodium, dexamethasone and ascorbic acid via the ERK pathway.

Aortic valve calcification (AVC) is an active process characterized by osteoblastic differentiation of the aortic valve interstitial cells (AVICs). Taurine is a free ß-amino acid and plays important physiological roles including protective effect of cardiovascular events. To evaluate the possible role of taurine in AVC, we isolated human AVICs from patients with type A dissection without leaflet disease. We demonstrated that the cultured AVICs express SM α-actin, vimentin and taurine transporter (TAUT), but not CD31, SM-myosin or desmin. We also established the osteoblastic differentiation model of the AVICs induced by pro-calcific medium (PCM) containing ß-glycerophosphate disodium, dexamethasone and ascorbic acid in vitro. The results showed that taurine attenuated the PCM-induced osteoblastic differentiation of AVICs by decreasing the alkaline phosphate (ALP) activity/expression and the expression of the core binding factor α1 (Cbfα1) in a dose-dependent manner (reaching the maximum protective effect at 10 mM), and taurine (10 mM) inhibited the mineralization level of AVICs in the form of calcium content significantly. Furthermore, taurine activated the extracellular signal-regulated protein kinase (ERK) pathway via TAUT, and the inhibitor of ERK (PD98059) abolished the effect of taurine on both ALP activity/expression and Cbfα1 expression. These results suggested that taurine could inhibit osteoblastic differentiation of AVIC via the ERK pathway.

Apelin-APJ induces ICAM-1, VCAM-1 and MCP-1 expression via NF-κB/JNK signal pathway in human umbilical vein endothelial cells.

Apelin receptor (APJ) deficiency has been reported to be preventive against atherosclerosis. However, the mechanism of this effect remains unknown. In this study, quantitative real-time RT-PCR, Western blotting and ELISA analyses revealed a significant increase in the expression of intercellular adhesion molecule-1(ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1) in human umbilical vein endothelial cells (HUVECs) treated with apelin. Inhibitors of cellular signal transduction molecules were used to demonstrate involvement of nuclear factor kappa-B (NF-κB) and c-Jun N-terminal kinase (JNK) pathways in apelin-APJ-induced activation of adhesion molecules and chemokines. Inhibition of APJ expression by RNA interference abrogated apelin-induced expression of adhesion molecules and chemokines and apelin-stimulated cellular signal transduction in HUVECs. The apelin-APJ system in endothelial cells is involved in the expression of adhesion molecules and chemokines, which are important for the initiation of endothelial inflammation-related atherosclerosis. Therefore, apelin-APJ and the cell signaling pathways activated by this system in endothelial cells may represent targets for therapy of atherosclerosis.

H19 Promotes Osteoblastic Transition by Acting as ceRNA of miR-140-5p in Vascular Smooth Muscle Cells.

Arterial medial calcification is a common disease in patients with type 2 diabetes, end-stage renal disease and hypertension, resulting in high incidence and mortality of cardiovascular event. H19 has been demonstrated to be involved in cardiovascular diseases like aortic valve diseases. However, role of H19 in arterial medial calcification remains largely unknown. We identified that H19 was upregulated in ß-glycerophosphate (ß-GP) induced vascular smooth muscle cells (VSMCs), a cellular calcification model in vitro. Overexpression of H19 potentiated while knockdown of H19 inhibited osteogenic differentiation of VSMCs, as demonstrated by changes of osteogenic genes Runx2 and ALP as well as ALP activity. Notably, H19 interacted with miR-140-5p directly, as demonstrated by luciferase report system and RIP analysis. Mechanistically, miR-140-5p attenuated osteoblastic differentiation of VSMCs by targeting Satb2 and overexpression of miR-140-5p blocked H19 induced elevation of Satb2 as well as the promotion of osteoblastic differentiation of VSMCs. Interestingly, over-expression of Satb2 induced phosphorylation of ERK1/2 and p38MAPK. In conclusion, H19 promotes VSMC calcification by acting as competing endogenous RNA of miR-140-5p and at least partially by activating Satb2-induced ERK1/2 and p38MAPK signaling.

Histone Lysine Methylation Modification and Its Role in Vascular Calcification.

Histone methylation is an epigenetic change mediated by histone methyltransferase, and has been connected to the beginning and progression of several diseases. The most common ailments that affect the elderly are cardiovascular and cerebrovascular disorders. They are the leading causes of death, and their incidence is linked to vascular calcification (VC). The key mechanism of VC is the transformation of vascular smooth muscle cells (VSMCs) into osteoblast-like phenotypes, which is a highly adjustable process involving a variety of complex pathophysiological processes, such as metabolic abnormalities, apoptosis, oxidative stress and signalling pathways. Many researchers have investigated the mechanism of VC and related targets for the prevention and treatment of cardiovascular and cerebrovascular diseases. Their findings revealed that histone lysine methylation modification may play a key role in the various stages of VC. As a result, a thorough examination of the role and mechanism of lysine methylation modification in physiological and pathological states is critical, not only for identifying specific molecular markers of VC and new therapeutic targets, but also for directing the development of new related drugs. Finally, we provide this review to discover the association between histone methylation modification and VC, as well as diverse approaches with which to investigate the pathophysiology of VC and prospective treatment possibilities.

The crosstalk between endothelial cells and vascular smooth muscle cells aggravates high phosphorus-induced arterial calcification.

Arterial calcification is highly prevalent, particularly in patients with end-stage renal disease (ESRD). The osteogenic differentiation of vascular smooth muscle cells (VSMCs) is the critical process for the development of arterial calcification. However, the detailed mechanism of VSMCs calcification remains to be elucidated. Here, we investigated the role of exosomes (Exos) derived from endothelial cells (ECs) in arterial calcification and its potential mechanisms in ESRD. Accelerated VSMCs calcification was observed when VSMCs were exposed to ECs culture media stimulated by uremic serum or high concentration of inorganic phosphate (3.5 mM Pi). and the pro-calcification effect of the ECs culture media was attenuated by exosome depletion. Exosomes derived from high concentrations of inorganic phosphate-induced ECs (ECsHPi-Exos) could be uptaken by VSMCs and promoted VSMCs calcification. Microarray analysis showed that miR-670-3p was dramatically increased in ECsHPi-Exos compared with exosomes derived from normal concentrations of inorganic phosphate (0.9 mM Pi) induced ECs (ECsNPi-Exos). Mechanistically, insulin-like growth factor 1 (IGF-1) was identified as the downstream target of miR-670-3p in regulating VSMCs calcification. Notably, ECs-specific knock-in of miR-670-3p of the 5/6 nephrectomy with a high-phosphate diet (miR-670-3pEC-KI + NTP) mice that upregulated the level of miR-670-3p in artery tissues and significantly increased artery calcification. Finally, we validated that the level of circulation of plasma exosomal miR-670-3p was much higher in patients with ESRD compared with healthy controls. Elevated levels of plasma exosomal miR-670-3p were associated with a decline in IGF-1 and more severe artery calcification in patients with ESRD. Collectively, these findings suggested that ECs-derived exosomal miR-670-3p could promote arterial calcification by targeting IGF-1, which may serve as a potential therapeutic target for arterial calcification in ESRD patients.

Taurine restores Axl/Gas6 expression in vascular smooth muscle cell calcification model.

Our previous studies demonstrated that taurine inhibits osteoblastic differentiation of vascular smooth muscular cells (VSMCs) via the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway, but the underlying mechanism is not elucidated. The tyrosine kinase receptor Axl and its ligand growth arrest-specific protein 6 (Gas6) are expressed in VSMCs. Axl/Gas6 signaling system is known to inhibit VSMCs calcification. We herein showed that taurine partially restored Axl and Gas6 expression in beta-glycerophosphate (beta-GP)-induced VSMC calcification model. Taurine also induced activation of ERK, but not other two MAPKs including c-jun N-terminal Kinase (JNK) and p38 in VSMCs. Either knockdown of the taurine transporter (TAUT) or treatment with the ERK-specific inhibitor PD98059 blocked the activation of ERK by taurine and abolished taurine-induced Axl/Gas6 expression and calcium deposition reduction in beta-GP-induced VSMC calcification model. These results demonstrate for the first time that taurine stimulates expression of Axl and Gas6 via TAUT/ERK signaling pathway in beta-GP-induced VSMC calcification model.

Apelin suppresses apoptosis of human vascular smooth muscle cells via APJ/PI3-K/Akt signaling pathways.

Apoptosis of vascular smooth muscle cells (VSMCs) plays an important role in regulating vascular remodeling during cardiovascular diseases. Apelin is the endogenous ligand for the G-protein-coupled receptor APJ and plays an important role in the cardiovascular system. However, the mechanisms of apelin on apoptosis of VSMCs have not been elucidated. Using a culture of human VSMCs as a model for the study of apoptosis, the relationship between apelin and apoptosis of human VSMCs and the signal pathway involved were investigated. Using western blotting, we confirmed that VSMCs could express APJ. To evaluate the possible role of apelin in VSMC apoptosis, we assessed its effect on apoptosis of human VSMCs. The results showed that apelin inhibited human VSMCs apoptosis induced by serum deprivation. Suppression of APJ with small-interfering RNA (siRNA) abolished the anti-apoptotic activity of apelin. Apelin increased Bcl-2 protein expression, but decreased Bax protein expression. An increase in activation of extracellular signal-regulated protein kinase (ERK) and Akt (a downstream effector of phosphatidylinositol 3-kinase) was shown after apelin stimulation. Suppression of APJ with siRNA abolished the apelin-induced activation of ERK and Akt. LY294002 (a PI3-K inhibitor) blocked apelin-induced activation of Akt and abolished the apelin-induced antiapoptotic activity. Our study suggests that apelin suppresses serum deprivation-induced apoptosis of human VSMCs, and that the anti-apoptotic action is mediated through the APJ/PI3-K/Akt signaling pathways.

L-carnitine and taurine synergistically inhibit the proliferation and osteoblastic differentiation of vascular smooth muscle cells.

AIM: To investigate the synergistic action of L-carnitine (LC) and taurine (TAU) on the proliferation and osteoblastic differentiation of vascular smooth muscle cells (VSMCs). METHODS: DNA and protein synthesis of VSMCs were assessed using scintillation counting. Alkaline phosphatase (ALP) activity and calcium content were determined to investigate the effects of LC and TAU on the osteoblastic differentiation and mineralization of VSMCs. TAU uptake by VSMCs was assayed. RNA interference was used to down-regulate the expression of the TAU transporter (TAUT) in rat VSMCs. RESULTS: LC and TAU synergistically inhibited the proliferation and beta-glycerophosphate (beta-GP)-induced osteoblastic differentiation of VSMCs as evidenced by the decreased [(3)H]thymidine incorporation, ALP activity and calcium deposition. Furthermore, LC stimulated the TAU uptake and TAUT expression in VSMCs. Suppression of TAUT with short hairpin RNA (shRNA) abolished the synergistic action of LC and TAU in VSMCs. CONCLUSION: The synergistic inhibitory action of LC and TAU on the proliferation and osteoblastic differentiation of VSMCs is attributable to the up-regulation of TAUT expression and TAU uptake by LC.