TCF7L2 (Transcription Factor 7-Like 2) Regulation of GATA6 (GATA-Binding Protein 6)-Dependent and -Independent Vascular Smooth Muscle Cell Plasticity and Intimal Hyperplasia.

Objective- TCF7L2 (transcription factor 7-like 2) is a Wnt-regulated transcription factor that maintains stemness and promotes proliferation in embryonic tissues and adult stem cells. Mice with a coronary artery disease-linked mutation in Wnt-coreceptor LRP6 (LDL receptor-related protein 6) exhibit vascular smooth muscle cell dedifferentiation and obstructive coronary artery disease, which are paradoxically associated with reduced TCF7L2 expression. We conducted a comprehensive study to explore the role of TCF7L2 in vascular smooth muscle cell differentiation and protection against intimal hyperplasia. Approach and Results- Using multiple mouse models, we demonstrate here that TCF7L2 promotes differentiation and inhibits proliferation of vascular smooth muscle cells. TCF7L2 accomplishes these effects by stabilization of GATA6 (GATA-binding protein 6) and upregulation of SM-MHC (smooth muscle cell myosin heavy chain) and cell cycle inhibitors. Accordingly, TCF7L2 haploinsufficient mice exhibited increased susceptibility to injury-induced hyperplasia, while mice overexpressing TCF7L2 were protected against injury-induced intimal hyperplasia compared with wild-type littermates. Consequently, the overexpression of TCF7L2 in LRP6 mutant mice rescued the injury-induced intimal hyperplasia. Conclusions- Our novel findings imply cell type-specific functional role of TCF7L2 and provide critical insight into mechanisms underlying the pathogenesis of intimal hyperplasia.

The effects of subclinical hypothyroidism on serum lipid level and TLR4 expression of monocyte in peripheral blood of rats.

OBJECTIVE: To observe effect of subclinical hypothyroidism (SCH) on serum lipid level and expression of toll-like receptor 4 (TLR4) in rats' peripheral blood mononuclear cells (PBMC). METHODS: Fifty Wistar female rats were divided into three groups: normal control (NC group; n=10), sham group (n=10), and L-T-4 (L-thyroxine) group (n=30, with thyroidectomy, fed with rich-calcium water after operation. 5 weeks later, abdominal subcutaneous injection of L-T-4: 0.95 µg/100g/d). 8 weeks later, the rats were killed then the peripheral blood was collected to determine the levels of serum thyroid-stimulating hormone (TSH), total thyroid hormone (TT4), total cholesterol (TC) and low density lipoprotein cholesterin (LDL-C). Rats in L-T-4 group were divided into normal lipid (NL) group) and high lipid (HL) group) according to lipid value of NC group. Monocytes were separated from blood to determine TLR4 expression by flow cytometry. RESULTS: In NL and HL groups TSH were higher than in NC and Sham groups (p<0.05). TT4 have no significant differences (p>0.05). TLR4, TLR4 mRNA, NF-κB (p65) were increased (p<0.05). TNF-α, IL-6 and IL-1ß were higher than in NC and sham groups (p<0.01). There were no significant differences of TLR4, TLR4 mRNA, NF-κB (p65), TNF-α, IL-6 and IL-1ß expression between NL and HL groups (p>0.05). CONCLUSION: TLR4, TLR4 mRNA, NF-κB (p65) of PBMC and TNF-α, IL-6, IL-1ß expression in serum were all increased in SCH rats, which was not related to serum dyslipidemia.

TLR4-mediated anti-atherosclerosis mechanisms of angiotensin-converting enzyme inhibitor--fosinopril.

Recently, angiotensin-converting enzyme inhibitor (ACEI) has gained increasing attention for its anti-atherosclerosis activity, but the underlying mechanism is unknown. In our study, we used rabbits fed with high-fat forage, as an atherosclerosis model to investigate the effect of fosinopril, which is an ACEI. Animals which received both high-fat forage and fosinopril, were maintained as the drug-treated group. Ultrasonography and Sudan III staining were used to determine the process of atherosclerosis. The expression of TLR4 and activity NF-κB were determined using western blot, RT-PCR and ELISA. The results showed that the atherosclerotic plaque was visible at sixteen weeks. More importantly, the atherosclerotic plaque was significantly decreased after fosinopril treatment. In the atherosclerosis model, the levels of TLR4 and NF-κB were increased, but this increased expression was inhibited in the fosinopril treated group. Our results demonstrated that TLR4 could be used as a potential biomarker for atherosclerosis and ACEI has the potential to be a new anti-atherosclerotic drug.

Fosinoprilat alleviates lipopolysaccharide (LPS)-induced inflammation by inhibiting TLR4/NF-κB signaling in monocytes.

OBJECTIVE: To evaluate the effect of the fosinoprilat on lipopolysacharides (LPS) induced inflammation in monocytes in vitro. METHODS: Human mononuclear THP1 cells were cultured in complete medium, treated with or without LPS and different concentrations (0,0.25,0.5,1,5,and 10µmol/L) of fosinoprilat. Toll-like receptor (TLR4) mRNA expression was detected by real-time RT-PCR and TLR4 protein level on the surface of monocyte was determined by flow cytometry. Nuclear factor-kappa B (NF-κB) protein level was detected by Western blotting. Cultured supernatant of the THP1 cells in different groups were analyzed by ELISA to detect the levels of interleukin (IL)-1ß, IL-6 and tumor necrosis factor (TNF-α). RESULTS: Both the mRNA and surface protein level of the TLR4 in the THP1 cells were enhanced by the LPS treatment and down-regulated by pretreatment of the fosinoprilat. Accordingly, LPS-induced NF-κB protein was decreased by the fosinoprilat treatment. The increasing secretion of IL-1ß, IL-6 and TNF-α induced by LPS could also be attenuated by the fosinoprilat treatment. CONCLUSION: The inhibitory effect of the fosinoprilat on the TRL4/NF-κB signaling pathway reveals a potential anti-inflammatory and anti-atherosclerosis target.

MicroRNA-146a-3p/HDAC1/KLF5/IKBα signal axis modulates plaque formation of atherosclerosis mice.

BACKGROUND: Atherosclerosis (AS) is a multifocal, smoldering immune inflammatory disease of medium and large arteries driven by lipids. The aim of this study is to discuss the mechanism of microRNA-146a-3p (miR-146a-3p)/histone deacetylase 1 (HDAC1)/Krüppel-like factor 5 (KLF5)/inhibitors of kappa B α (IKBα) signal axis in plaque formation of AS mice. METHODS: ApoE-/- mice were fed with high-fat feed for 12 weeks to establish AS mice model. The expression of miR-146a-3p, KLF5, HDAC1 and IKBα in aortic wall tissues of AS mice was tested. The targeting relationship between miR-146a-3p and HDAC1 was verified. AS mice were injected with miR-146a-3p antagomir or HDAC1 overexpression to verify the impacts of miR-146a-3p and HDAC1 on blood lipids and inflammatory factors in serum, aortic wall apoptotic cells, antioxidant stress capacity and the plaque area in AS mice. VECs proliferation and apoptosis were also measured in vitro. RESULTS: miR-146a-3p and KLF5 were increased while HDAC1 and IKBα were reduced in aortic wall tissues of AS mice. miR-146a-3p directly targeted to HDAC1. Depletion of miR-146a-3p or restoration of HDAC1 was correlated to lower plasma lipid level, reduced inflammatory factors in serum, attenuated aortic wall apoptosis, increased antioxidant stress capacity and improved the stability of pathological plaque of AS mice. miR-146a-3p down-regulation or HDAC1 up-regulation promoted VECs proliferation and inhibited apoptosis. CONCLUSION: Functional studies show that depleted miR-146a-3p advances HDAC1 and IKBα expression as well as inhibits KLF5 expression to facilitate the stability of pathological plaques in AS mice.

Addition of Estradiol to Cross-Sex Testosterone Therapy Reduces Atherosclerosis Plaque Formation in Female ApoE-/- Mice.

The contributions of estradiol and testosterone to atherosclerotic lesion progression are not entirely understood. Cross-sex hormone therapy (XHT) for transgender individuals dramatically alters estrogen and testosterone levels and consequently could have widespread consequences for cardiovascular health. Yet, no preclinical research has assessed atherosclerosis risk after XHT. We examined the effects of testosterone XHT after ovariectomy on atherosclerosis plaque formation in female mice and evaluated whether adding low-dose estradiol to cross-sex testosterone treatments after ovariectomy reduced lesion formation. Six-week-old female ApoE-/- C57BL/6 mice underwent ovariectomy and began treatments with testosterone, estradiol, testosterone with low-dose estradiol, or vehicle alone until euthanized at 23 weeks of age. Atherosclerosis lesion progression was measured by Oil Red O stain and confirmed histologically. We found reduced atherosclerosis in the estradiol- and combined testosterone/estradiol-treated mice compared with those treated with testosterone or vehicle only in the whole aorta (-75%), aortic arch (-80%), and thoracic aorta (-80%). Plaque size was similarly reduced in the aortic sinus. These reductions in lesion size after combined testosterone/estradiol treatment were comparable to those obtained with estrogen alone. Testosterone/estradiol combined therapy resulted in less atherosclerosis plaque formation than either vehicle or testosterone alone after ovariectomy. Testosterone/estradiol therapy was comparable to estradiol replacement alone, whereas mice treated with testosterone only fared no better than untreated controls after ovariectomy. Adding low-dose estrogen to cross-sex testosterone therapy after oophorectomy could improve cardiovascular outcomes for transgender patients. Additionally, these results contribute to understanding of the effects of estrogen and testosterone on atherosclerosis progression.

Apelin-13 protects the heart against ischemia-reperfusion injury through the RISK-GSK-3ß-mPTP pathway.

INTRODUCTION: Apelin plays an important role in the protection against myocardial ischemia-reperfusion (I/R) injury, while the mechanism still remains unclear. In the current study, we aimed to evaluate the protective effect of apelin-13, and the main mechanism. MATERIAL AND METHODS: The in vivo I/R injury model (Sprague-Dawley rat) was established, then infarct size, expression levels of phospho-protein kinase B (p-Akt), phospho-extracellular signal-regulated kinase (p-ERK) and phospho-glycogen synthase kinase-3ß (p-GSK-3ß) were measured. The fluorescence intensity of tetramethylrhodamine ethyl ester perchlorate (TMRE) of the isolated myocardial cells was determined to evaluate the opening of the mitochondrial permeability transition pore (mPTP) caused by oxidant stress and hypoxia/reoxygenation. RESULTS: For the established I/R injury model, apelin-13 and SB216763 (GSK-3ß inhibitor) significantly reduced the infarct size (p < 0.05), which could be abolished by LY294002 (PI3K inhibitor), PD98059 (MEK inhibitor) and atractyloside (mPTP accelerator). The enhanced expression levels of p-Akt, p-ERK and p-GSK-3ß caused by apelin-13 (p < 0.05) could be counteracted by LY294002 and PD98059. The reduced fluorescence intensity of TMRE in the H2O2/apelin-13 and H2O2/SB216763 treated groups was significantly lower (p < 0.05), indicating that apelin-13 and SB216763 could reduce the decline in mitochondrial membrane potential caused by oxidant stress, and the fluorescence intensity in the hypoxia/reoxygenation + apelin-13 group was significantly lower (p < 0.05), which suggested that apelin-13 could inhibit the mitochondrial membrane potential changes induced by hypoxia/reoxygenation. CONCLUSIONS: The protective mechanism of apelin-13 might be that inactivation of GSK-3ß could inhibit the opening of mPTP by activating PI3K/Akt and ERK1/2 involved in the reperfusion injury salvage kinase (RISK) pathway.

Glucagon-like peptide-1 protects against cardiac microvascular endothelial cells injured by high glucose.

OBJECTIVE: To investigate the protective effect of glucagon-like peptid-1 (GLP-1) against cardiac microvascular endothelial cell (CMECs) injured by high glucose. METHODS: CMECs were isolated and cultured. Superoxide assay kit and dihydroethidine (DHE) staining were used to assess oxidative stress. TUNEL staining and caspase 3 expression were used to assess the apoptosis of CMECs. H89 was used to inhibit cAMP/PKA pathway; fasudil was used to inhibit Rho/ROCK pathway. The protein expressions of Rho, ROCK were examined by Western blot analysis. RESULTS: High glucose increased the production of ROS, the activity of NADPH, the apoptosis rate and the expression level of Rho/ROCK in CMECs, while GLP-1 decreased high glucose-induced ROS production, the NADPH activity and the apoptosis rate and the expression level of Rho/ROCK in CMECs, the difference were statistically significant (P<0.05). CONCLUSIONS: GLP-1 could protect the cardiac microvessels against oxidative stress and apoptosis. The protective effects of GLP-1 are dependent on downstream inhibition of Rho through a cAMP/PKA-dependent manner, resulting in a subsequent decrease in the expression of NADPH oxidase.

Protective effect of Salvia miltiorrhiza aqueous extract on myocardium oxidative injury in ischemic-reperfusion rats.

Salvia miltiorrhiza has strong antioxidative activity. They may have a strong potential as cardioprotective agents in ischemic-reperfusion injury. Experiments were carried out in Sprague-Dawley rats with myocardium ischemia reperfusion (IR). Myocardial injuries during IR were determined by changes in electrocardiogram analysis of arrhythmias, antioxidant enzyme activities, AST, CK-MB, lactate dehydrogenase (LDH) levels, and myocyte apoptosis. Results showed that S. miltiorrhiza aqueous extract (SAME) pre-treatment significantly decreased the ST-segment (ΣST120) and myocardium MDA, AST, CK-MB, lactate dehydrogenase (LDH) levels, increased myocardium antioxidant enzyme activities, and inhibit myocardium cell apoptosis. Furthermore, the SAME pre-treatment significantly upregulated p-JAK2 and p-STAT3 protein expression, decreased myocardium TNF-α and IL-6 concentrations in IR rats. The levels of TNF-α and IL-6 were positively correlated with the changes in myocardium p-JAK2 and p-STAT3 protein expression levels in IR rats. It can be concluded that the SAME pre-treatment has anti-ischemic and anti-apoptosis activity in heart IR rats. SAME pre-treatment protects heart against IR injury, at least in part, through its stimulating effects on injury-induced deactivation of JAK2/STAT3 signaling pathway.