Endothelial deficiency of insulin-like growth factor-1 receptor reduces endothelial barrier function and promotes atherosclerosis in Apoe-deficient mice.

Insulin-like growth factor-1 (IGF-1) decreases atherosclerosis in apolipoprotein E (Apoe)-deficient mice when administered systemically. However, mechanisms for its atheroprotective effect are not fully understood. We generated endothelium-specific IGF-1 receptor (IGF1R)-deficient mice on an Apoe-deficient background to assess effects of IGF-1 on the endothelium in the context of hyperlipidemia-induced atherosclerosis. Endothelial deficiency of IGF1R promoted atherosclerotic burden, when animals were fed on a high-fat diet for 12 wk or normal chow for 12 mo. Under the normal chow feeding condition, the vascular relaxation response to acetylcholine was increased in the endothelial IGF1R-deficient aorta; however, feeding of a high-fat diet substantially attenuated the relaxation response, and there was no difference between endothelial IGF1R-deficient and control mice. The endothelium and its intercellular junctions provide a barrier function to the vasculature. In human aortic endothelial cells, IGF-1 upregulated occludin, claudin 5, VE-cadherin, JAM-A, and CD31 expression levels, and vice versa, specific IGF1R inhibitor, picropodophyllin, an IGF1R-neutralizing antibody (αIR3), or siRNA to IGF1R abolished the IGF-1 effects on junction and adherens proteins, suggesting that IGF-1 promoted endothelial barrier function. Moreover, endothelial transwell permeability assays indicated that inhibition of IGF-1 signaling elevated solute permeability through the monolayer of human aortic endothelial cells. In summary, endothelial IGF1R deficiency increases atherosclerosis, and IGF-1 positively regulates tight junction protein and adherens junction protein levels and endothelial barrier function. Our findings suggest that the elevation of the endothelial junction protein level is, at least in part, the mechanism for antiatherogenic effects of IGF-1.NEW & NOTEWORTHY Endothelial insulin-like growth factor-1 (IGF-1) receptor deficiency significantly elevated atherosclerotic burden in apolipoprotein E-deficient mice, mediated at least in part by downregulation of intercellular junction proteins and, thus, elevated endothelial permeability. This study revealed a novel role for IGF-1 in supporting endothelial barrier function. These findings suggest that IGF-1's ability to promote endothelial barrier function may offer a novel therapeutic strategy for vascular diseases such as atherosclerosis.

SM22α (Smooth Muscle Protein 22-α) Promoter-Driven IGF1R (Insulin-Like Growth Factor 1 Receptor) Deficiency Promotes Atherosclerosis.

Objective- IGF-1 (insulin-like growth factor 1) is a major autocrine/paracrine growth factor, which promotes cell proliferation, migration, and survival. We have shown previously that IGF-1 reduced atherosclerosis and promoted features of stable atherosclerotic plaque in Apoe-/- mice-an animal model of atherosclerosis. The aim of this study was to assess effects of smooth muscle cell (SMC) IGF-1 signaling on the atherosclerotic plaque. Approach and Results- We generated Apoe-/- mice with IGF1R (IGF-1 receptor) deficiency in SMC and fibroblasts (SM22α [smooth muscle protein 22 α]-CreKI/IGF1R-flox mice). IGF1R was decreased in the aorta and adventitia of SM22α-CreKI/IGF1R-flox mice and also in aortic SMC, embryonic, skin, and lung fibroblasts isolated from SM22α-CreKI/IGF1R-flox mice. IGF1R deficiency downregulated collagen mRNA-binding protein LARP6 (La ribonucleoprotein domain family, member 6) and vascular collagen, and mice exhibited growth retardation. The high-fat diet-fed SM22α-CreKI/IGF1R-flox mice had increased atherosclerotic burden and inflammatory responses. α-SMA (α-smooth muscle actin)-positive plaque cells had reduced proliferation and elevated apoptosis. SMC/fibroblast-targeted decline in IGF-1 signaling decreased atherosclerotic plaque SMC, markedly depleted collagen, reduced plaque fibrous cap, and increased plaque necrotic cores. Aortic SMC isolated from SM22α-CreKI/IGF1R-flox mice had decreased cell proliferation, migration, increased sensitivity to apoptosis, and these effects were associated with disruption of IGF-1-induced Akt signaling. Conclusions- IGF-1 signaling in SMC and in fibroblast is a critical determinant of normal vascular wall development and atheroprotection.

Astragaloside IV attenuates myocardial ischemia/reperfusion injury in rats via inhibition of calcium-sensing receptor-mediated apoptotic signaling pathways.

Astragaloside IV (AsIV) is an active saponin extracted from Astragalus membranaceus, which has shown cardioprotective effects in a number of experimental animals. In this study we investigated the molecular mechanisms by which AsIV attenuated the myocardial ischemia reperfusion (MI/R)-induced injury in vitro and in vivo by focusing on calcium-sensing receptor (CaSR) and extracellular signal-regulated kinase 1/2 (ERK1/2). Rat neonatal cardiac myocytes were subjected to a hypoxia/reoxygenation (H/R) procedure in vitro, which significantly decreased the cell viability, increased lactate dehydrogenase (LDH) release, induced cardiomyocyte apoptosis, and increased [Ca2+]i. H/R also increased the expression of CaSR and decreased ERK1/2 phosphorylation levels in H/R-exposed myocytes. Pretreatment with AsIV (60 µmol/L) significantly improved the cell viability and decreased LDH release, attenuated myocyte apoptosis, decreased [Ca2+]i and CaSR expression, and increased the ERK1/2 phosphorylation levels. The protective effects of AsIV against H/R injury were partially inhibited by co-treatment with a CaSR agonist, gadolinium chloride (GdCl3) or with a specific ERK1/2 inhibitor U0126. For in vivo studies, a rat MI/R model was established. Pre-administration of AsIV (80 mg/kg every day, ig) significantly decreased the myocardium infarct size, creatine kinase-MB (CK-MB) production, serum cardiac troponin (cTnI) levels, and cardiomyocyte apoptosis in the rats with MI/R injury. The therapeutic effects of AsIV were associated with the downregulation of CaSR expression and upregulation of ERK1/2 phosphorylation in myocardial tissues. In summary, astragaloside IV attenuates myocardial I/R injury via inhibition of CaSR/ERK1/2 and the related apoptotic signaling pathways.

Nuclear complex of glyceraldehyde-3-phosphate dehydrogenase and DNA repair enzyme apurinic/apyrimidinic endonuclease I protect smooth muscle cells against oxidant-induced cell death.

Atherosclerotic plaque destabilization is the major determinant of most acute coronary events. Smooth muscle cell (SMC) death contributes to plaque destabilization. Here, we describe a novel antiapoptotic mechanism in vascular SMCs that involves interaction of nuclear glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with apurinic/apyrimidinic endonuclease 1 (Ape1), the major oxidized DNA repair enzyme. GAPDH down-regulation potentiated H2O2-induced DNA damage and SMC apoptosis. Conversely, GAPDH overexpression decreased DNA damage and protected SMCs against apoptosis. Ape1 down-regulation reversed the resistance of GAPDH-overexpressing cells to DNA damage and apoptosis, which indicated that Ape1 is indispensable for GAPDH-dependent protective effects. GAPDH bound Ape1 in the SMC nucleus, and blocking (or oxidation) of GAPDH active site cysteines suppressed GAPDH/Ape1 interaction and potentiated apoptosis. GAPDH up-regulated Ape1 via a transcription factor homeobox protein Hox-A5-dependent mechanism. GAPDH levels were reduced in atherosclerotic plaque SMCs, and this effect correlated with oxidative stress and SMC apoptosis. Thus, we demonstrated that nuclear GAPDH/Ape1 interaction preserved Ape1 activity, reduced DNA damage, and prevented SMC apoptosis. Suppression of SMC apoptosis by maintenance of nuclear GAPDH/Ape1 interactions may be a novel therapy to increase atherosclerotic plaque stability.-Hou, X., Snarski, P., Higashi, Y., Yoshida, T., Jurkevich, A., Delafontaine, P., Sukhanov, S. Nuclear complex of glyceraldehyde-3-phosphate dehydrogenase and DNA repair enzyme apurinic/apyrimidinic endonuclease I protect smooth muscle cells against oxidant-induced cell death.

Sirt3 is essential for apelin-induced angiogenesis in post-myocardial infarction of diabetes.

Heart failure following myocardial infarction (MI) is the leading cause of death in diabetic patients. Angiogenesis contributes to cardiac repair and functional recovery in post-MI. Our previous study shows that apelin (APLN) increases Sirtuin 3 (Sirt3) expression and ameliorates diabetic cardiomyopathy. In this study, we further investigated the direct role of Sirt3 in APLN-induced angiogenesis in post-MI model of diabetes. Wild-type (WT) and Sirt3 knockout (Sirt3KO) mice were induced into diabetes by i.p. streptozotocin (STZ). STZ mice were then subjected to MI followed by immediate intramyocardial injection with adenovirus-apelin (Ad-APLN). Our studies showed that Sirt3 expression was significantly reduced in the hearts of STZ mice. Ad-APLN treatment resulted in up-regulation of Sirt3, angiopoietins/Tie-2 and VEGF/VEGFR2 expression together with increased myocardial vascular densities in WT-STZ+MI mice, but these alterations were not observed in Sirt3KO-STZ+MI mice. In vitro, overexpression of APLN increased Sirt3 expression and angiogenesis in endothelial progenitor cells (EPC) from WT mice, but not in EPC from Sirt3KO mice. APLN gene therapy increases angiogenesis and improves cardiac functional recovery in diabetic hearts via up-regulation of Sirt3 pathway.

Apelin gene therapy increases myocardial vascular density and ameliorates diabetic cardiomyopathy via upregulation of sirtuin 3.

Microvascular insufficiency contributes to cardiac hypertrophy and worsens heart dysfunction in diabetic cardiomyopathy. Our recent study shows that apelin may protect ischemic heart failure via upregulation of sirtuin 3 (Sirt3) and angiogenesis. This study investigated whether apelin promotes angiogenesis and ameliorates diabetic cardiomyopathy via activation of Sirt3. Wild-type (WT) and diabetic db/db mice were administrated with adenovirus-apelin to overexpressing apelin. In WT mice, overexpression of apelin increased Sirt3, VEGF/VEGFR2, and angiopoietin-1 (Ang-1)/Tie-2 expression in the heart. In vitro, treatment of endothelial cells (EC) with apelin increased VEGF and Ang-1 expression. In EC isolated from Sirt3KO mice, however, apelin treatment did not upregulate VEGF and Ang-1 expression. Moreover, apelin-induced angiogenesis was diminished in Sirt3KO mice. In db/db mice, the basal levels of apelin and Sirt3 expression were significantly reduced in the heart. This was accompanied by a significant reduction of capillary and arteriole densities in the heart. Overexpression of apelin increased Sirt3, VEGF/VEGFR2, and Ang-1/Tie-2 expression together with improved vascular density in db/db mice. Overexpression of apelin further improved cardiac function in db/db mice. Treatment with apelin significantly attenuated high glucose (HG)-induced reactive oxygen species (ROS) formation and EC apoptosis. The protection of apelin against HG-induced ROS formation and EC apoptosis was diminished in Sirt3KO-EC. We conclude that apelin gene therapy increases vascular density and alleviates diabetic cardiomyopathy by a mechanism involving activation of Sirt3 and upregulation of VEGF/VEGFR2 and Ang-1/Tie-2 expression.

Polymorphism -433 C>T of the Osteopontin gene is associated with the susceptibility to develop gliomas and their prognosis in a Chinese cohort.

AIM: To investigate role of the Osteopontin (OPN) genetic polymorphisms in the susceptibility to gliomas and their prognosis. METHODS: A total of 248 Chinese glioma patients and 281 age and sex matched healthy controls were recruited. The genetic polymorphisms at three loci, namely, -156 GG>G, -443 C>T and -66T>G, were determined. The log-rank test and Kaplan- Meier analysis were introduced to assess the effect of OPN gene polymorphisms on patient survival. RESULTS: We found that the genotype frequencies of OPN -443 C>T polymorphism were significantly different between glioma patients and controls. Multivariable analyses showed a higher risk for gliomas in -443 CC genotype carriers compared to -443TT carriers (P<0.001). In addition, we also found the OPN -443 C>T polymorphism was closely related to the gliomas' tumor grade. The -443 C>T polymorphism also affected the tumor OPN expression level, but not the serum OPN level. More importantly, the -443 C>T polymorphism was significantly associated with the prognosis of these patients regardless of their treatment status. The patients with -443CC genotype had a poorer prognosis than those with -443TT and -443CT genotypes. In contrast, the -156 G>GG and -66T>G polymorphisms were not associated with risk, clinical characteristics, or prognosis of gliomas. CONCLUSION: This study suggests that the -443C>T gene polymorphisms may be used as a molecular marker for glioma occurrence and clinical outcome in glioma patients.

The gene polymorphism of LOX1 predicts the incidence of LVH in patients with essential hypertension.

BACKGROUND: Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) has been shown to play an important role in cardiac remodeling under different pathologic conditions. The role of genetic polymorphisms in the LOX1 gene, however, remains unclear in the development of left ventricular hypertrophy (LVH) for patients with hypertension. METHODS: A total of 536 patients diagnosed with essential hypertension (EH) were recruited in this study. Patients were assigned to the LVH+ (n=143) and LVH- (n=393) groups, respectively. The serum LOX1 level was measured and three single nucleotide polymorphisms (SNPs), i.e. intron 4 (G→A), intron 5(T→G), and 3' UTR (T→C) of the LOX1 gene were genotyped. RESULTS: The genotype frequencies of intron 4 G>A and 3'UTR T>C were not significantly different between the LVH+ and LVH- groups (both P>0.05), however, frequencies of 501G>C were significantly different between those two groups (P=0.007). The 501CC genotype carriers had a markedly higher serum LOX1 level and an increased risk to develop LVH (adjusted OR=2.444, adjusted P=0.002). There was a positive correlation between serum LOX1 level and left ventricular mass index (r=0.907, P<0.001); a cutoff value of 1.0 ng/mL for sLOX-1 was applied to significantly differentiate the LVH+ patients from the LVH- patients with 84% sensitivity and 86% specificity. CONCLUSION: Our data suggest that both the 501>C SNP in the LOX1 gene and the serum LOX1 level may be used to predict the development of LVH among EH patients.

Advanced glycation endproducts trigger autophagy in cadiomyocyte via RAGE/PI3K/AKT/mTOR pathway.

UNLABELLED: Previous studies showed that the accumulation of advanced glycation end products (AGEs) induce cardiomyocyte apoptoisis, leading to heart dysfunction. However, the effect of AGEs on another cell death pathway, autophagy, in cardiomyocytes remains unknown. METHODS: Rat neonate cardiomyocytes were cultured and treated with AGEs at different concentration. Two classic autophagy markers, microtubule-associated protein 1 light chain 3 (LC3) and Beclin-1, were detected by western blot assay. The inhibition of RAGE and phosphatidylinositol 3-phosphate kinase (PI3K)/Akt/mTOR pathway were applied to cells, respectively. RESULTS: AGEs administration enhanced the expression of Beclin-1 and LC3 II in cardiomyocytes, increased the number of autophagic vacuoles and impaired the cell viability in dose-dependant manners. Also, AGEs inhibited the PI3K/Akt/mTOR pathway via RAGE. Inhibition of RAGE with RAGE antibody reduced expression of Beclin-1 and LC3 II/I and inhibited the cellular autophagy, accompanied by the reactivation of PI3K/Akt/mTOR pathway in cultured cells. Notably, the presence of inhibition of PI3K/Akt/mTOR pathway abolished the protective effect of RAGE inhibition on cardiomyocytes. CONCLUSION: This study provides evidence that AGEs induces cardiomyocyte autophagy by, at least in part, inhibiting the PI3K/Akt/mTOR pathway via RAGE.

Polymorphisms of receptor for advanced glycation end products and risk of epithelial ovarian cancer in Chinese patients.

BACKGROUND: Given the roles of receptor for advanced glycation end products (RAGE) in the pathogenesis of carcinogenesis, we propose that RAGE polymorphisms may be associated with risk of epithelial ovarian carcinoma (EOC). METHOD: This case-control study included 190 women over 40 years of age who were diagnosed with primary EOC and 210 healthy control subjects. RAGE gene polymorphisms, including 82G>S,-374T>A,-429C>T,and 1704G>T were determined. RESULTS: We found that only the frequencies of the 82G>S polymorphisms were significantly different between the EOC cases and controls. The 82SS genotype was significantly higher in EOC patients than in controls (37.89% vs. 23.33%,P<0.001). With the 82 GG genotype as reference, the OR for 82SS homozygous carriers reached to 2.65 (95% CI: 1.54-4.58; P =0.0004) after adjustment for age, smoking status, body mass index, family history, usage of contraceptives, tubal ligation history, use of menopausal hormones and menopausal status. The 82S allele carriage presented a higher risk for EOC (OR=1.71; 95% CI, 1.29-2.26; P=0.0002). The polymorphisms of 1704G>T,-374T>A and -429C>T did not affect the EOC risk. CONCLUSION: This result suggests that the 82G>S polymorphism of RAGE gene may be associated with the susceptibility of EOC.

Polymorphism of the RAGE affects the serum inflammatory levels and risk of ischemic stroke in a Chinese population.

BACKGROUND: Increasing evidence shows that inflammation plays an important role in the occurrence and progression of acute ischemic stroke. The receptor for advanced glycation end products (RAGE) has been documented to involve in the pathogenic mechanisms of a variety of neurological diseases, including ischemic stroke (IS). However, the impact of RAGE gene polymorphisms on the susceptibility to IS has not been reported. We thus explored the association between RAGE gene polymorphisms and the susceptibility to IS. METHOD: A total of 384 patients with IS and 425 healthy controls were enrolled in this study. Three genetic polymorphisms of RAGE gene (82G/S, -429T/C and -374T/A) were determined. The serum levels of soluble RAGE (sRAGE), intetleukin-6 (IL-6), high sensitivity-C reaction protein (hs-CRP) and plasminogen activator inhibitor-1 (PAI-1) were detected. RESULTS: Among the studied polymorphisms, only the polymorphism at 82G/S of RAGE gene was associated with the risk for ischemic stroke irrespective of the stroke subtypes. The 82S/S homozygote carriers had a significantly increased risk for ischemic stroke [adjusted odds ratio (OR): 2.297; p<0.001]. The haplotype analyses showed that the C-429S82T-374 and T-429S82A-374 had higher risk to develop IS (OR=1.864 and 1.931, respectively, all p<0.01), while the C-429G82T-374 showed a protective effect against IS susceptibility (OR=0.568, p=0.001). In addition, the 82S/S homozygote carriers had a higher inflammatory level compared with 82G/S and 82G/G genotypes, indicated by lower serum sRAGE level, higher serum IL-6, hs-CRP and PAI-1 levels. The polymorphisms at -374 and -429 loci did not influence the stroke risk and the above mentioned inflammation cytokines. CONCLUSION: Our results showed a close correlation between the 82G/S polymorphism and the susceptibility to IS, suggesting the 82G/S polymorphism may be used as a genetic marker for the prediction of stroke occurrence in high risk subjects.

OPN gene polymorphism and the serum OPN levels confer the susceptibility and prognosis of ischemic stroke in Chinese patients.

AIM: To investigate the association of Osteopontin (OPN) gene polymorphism and serum thrombin-cleaved OPN level with the susceptibility to ischemic stroke (IS) and its prognosis. METHODS: A total of 377 patients with IS and 551 healthy individuals were recruited. The OPN gene polymorphisms at -156 G>GG, -443 C>T and -66 T>G were genotyped. Serum full-length and the thrombin-cleaved OPN were determined. RESULTS: We found that only the -443 C>T polymorphism was significantly associated with the susceptibility to IS. The -443 CC represented a near 2 time higher risk for IS incidence than TT carriers. Also, the -443 CC genotype had significantly poorer outcome and they significantly had higher occurrence for bad recovery as determined by modified Rankin Scale (mRS) (OR=2.18, p=0.043) and Barthel Index (BI) (OR=2.12, p=0.05). The mean serum thrombin-cleaved OPN level in IS group were significantly higher than that in control group. ROC analysis showed that the thrombin-cleaved OPN level (cut-off value, 166.8 ng/ml) can discriminate IS patients from controls with a specificity of 86.3% and a sensitivity of 57.7%. The serum thrombin-cleaved OPN was significantly associated with the clinical outcome at 12 months after discharge from hospital. CONCLUSION: These results suggest that the -443 C>T polymorphism of OPN gene and serum thrombin-cleaved OPN can be used as a biomarker for the susceptibility and prognosis of IS patients.

ß­aminoisobutyric acid ameliorates hypertensive vascular remodeling via activating the AMPK/SIRT1 pathway in VSMCs.

Excessive proliferation and migration of vascular smooth muscle cells (VSMCs) play a fundamental role in the pathogenesis of hypertension-related vascular remodeling. ß-aminoisobutyric acid (BAIBA) is a nonprotein ß-amino acid with multiple pharmacological actions. Recently, BAIBA has been shown to attenuate salt­sensitive hypertension, but the role of BAIBA in hypertension-related vascular remodeling has yet to be fully clarified. This study examined the potential roles and underlying mechanisms of BAIBA in VSMC proliferation and migration induced by hypertension. Primary VSMCs were cultured from the aortas of Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Our results showed that BAIBA pretreatment obviously alleviated the phenotypic transformation, proliferation, and migration of SHR-derived VSMCs. Exogenous BAIBA significantly inhibited the release of inflammatory cytokines by diminishing phosphorylation and nuclear translocation of p65 NFκB, retarding IκBα phosphorylation and degradation, as well as erasing STAT3 phosphorylation in VSMCs. Supplementation of BAIBA triggered Nrf2 dissociation from Keap1 and inhibited oxidative stress in VSMCs from SHR. Mechanistically, activation of the AMPK/sirtuin 1 (SIRT1) axis was required for BAIBA to cube hypertension-induced VSMC proliferation, migration, oxidative damage and inflammatory response. Most importantly, exogenous BAIBA alleviated hypertension, ameliorated vascular remodeling and fibrosis, abated vascular oxidative burst and inflammation in SHR, an effect that was abolished by deficiency of AMPKα1 and SIRT1. BAIBA might serve as a novel therapeutic agent to prevent vascular remodeling in the context of hypertension.

Genomic insights into the genetic structure and population history of Mongolians in Liaoning Province.

The Mongolian population exceeds six million and is the largest population among the Mongolic speakers in China. However, the genetic structure and admixture history of the Mongolians are still unclear due to the limited number of samples and lower coverage of single-nucleotide polymorphism (SNP). In this study, we genotyped genome-wide data of over 700,000 SNPs in 38 Mongolian individuals from Fuxin in Liaoning Province to explore the genetic structure and population history based on typical and advanced population genetic analysis methods [principal component analysis (PCA), admixture, FST, f 3 -statistics, f 4 -statistics, qpAdm/qpWave, qpGraph, ALDER, and TreeMix]. We found that Fuxin Mongolians had a close genetic relationship with Han people, northern Mongolians, other Mongolic speakers, and Tungusic speakers in East Asia. Also, we found that Neolithic millet farmers in the Yellow River Basin and West Liao River Basin and Neolithic hunter-gatherers in the Mongolian Plateau and Amur River Basin were the dominant ancestral sources, and there were additional gene flows related to Eurasian Steppe pastoralists and Neolithic Iranian farmers in the gene pool of Fuxin Mongolians. These results shed light on dynamic demographic history, complex population admixture, and multiple sources of genetic diversity in Fuxin Mongolians.

Gypenoside inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration.

BACKGROUND: Gypenoside (GP) is the major bioactive constituent of G. pentaphyllum, a traditional Chinese medicine. It has been reported that GP can affect autophagy and lipid metabolism in cultured cells. We hypothesize that GP can inhibit foam cell formation in cultured macrophages through autophagy modulation. METHODS: THP1 cells were cultured and treated with oxidized low-density lipoprotein (ox-LDL), followed by GP treatment at different concentrations. The autophagy flux was evaluated using western blot and confocal microscope analyses. The ox-LDL uptake and foam cell formation abilities were measured. RESULTS: We found that ox-LDL impaired the autophagy flux in the cultured macrophages, indicated by a significant reduction of LC3-II and autophagosome puncta quantification, as well as an accumulation of p62 proteins. GP treatment, however, dose-dependently restored the autophagy flux impaired by ox-LDL and reduced the ox-LDL uptake and foam cell transformation from THP1 cells, which can be alleviated, or exacerbated, by modulation of autophagy status using autophagy enhancer or inhibitor. Coimmunoprecipitation assays showed that GP up-regulated Srit1 and FOXO1 expression and enhanced their direct interaction, and thus contributed to the regulation of autophagy. CONCLUSION: GP inhibits ox-LDL uptake and foam cell formation through enhancing Sirt1-FOXO1 mediated autophagy flux restoration, suggesting this compound has therapeutic potential for atherosclerosis.

Ginsenoside Rg1 attenuates mechanical stress-induced cardiac injury via calcium sensing receptor-related pathway.

BACKGROUND: Ginsenoside Rg1 (Rg1) has been well documented to be effective against various cardiovascular disease. The aim of this study is to evaluate the effect of Rg1 on mechanical stress-induced cardiac injury and its possible mechanism with a focus on the calcium sensing receptor (CaSR) signaling pathway. METHODS: Mechanical stress was implemented on rats through abdominal aortic constriction (AAC) procedure and on cardiomyocytes and cardiac fibroblasts by mechanical stretching with Bioflex Collagen I plates. The effects of Rg1 on cell hypertrophy, fibrosis, cardiac function, [Ca2+]i, and the expression of CaSR and calcineurin (CaN) were assayed both on rat and cellular level. RESULTS: Rg1 alleviated cardiac hypertrophy and fibrosis, and improved cardiac decompensation induced by AAC in rat myocardial tissue and cultured cardiomyocytes and cardiac fibroblasts. Importantly, Rg1 treatment inhibited CaSR expression and increase of [Ca2+]i, which similar to the CaSR inhibitor NPS2143. In addition, Rg1 treatment inhibited CaN and TGF-ß1 pathways activation. Mechanistic analysis showed that the CaSR agonist GdCl3 could not further increase the [Ca2+]i and CaN pathway related protein expression induced by mechanical stretching in cultured cardiomyocytes. CsA, an inhibitor of CaN, inhibited cardiac hypertrophy, cardiac fibrosis, [Ca2+]i and CaN signaling but had no effect on CaSR expression. CONCLUSION: The activation of CaN pathway and the increase of [Ca2+]i mediated by CaSR are involved in cardiac hypertrophy and fibrosis, that may be the target of cardioprotection of Rg1 against myocardial injury.

Association between transforming growth factor beta1 polymorphisms and atrial fibrillation in essential hypertensive subjects.

BACKGROUND: The association of TGF beta1 polymorphisms and atrial fibrillation (AF) in essential hypertensive (EH) subjects remains unknown. Methods EH subjects with AF (EH+AF+) and sinus rhythm (EH+AF-) were enrolled. The polymorphisms of +869 T --> C at codon 10 and + 915 G --> C at codon 25, were genotyped. The clinical characteristics including serum TGF beta1 levels were detected. RESULTS: The GG genotypes of TGF beta1 +915 G --> C at codon 25 were more prevalent in subjects from EH+AF+ group than those from EH+AF- group (P = 0.009). The subjects with GG genotype from EH+AF+ group had the highest mean serum TGF beta1 level, which was significantly higher than that of GG genotype subjects from EH+AF- group (3.18 +/- 0.24 ng/dl vs.2.29 +/- 0.14 ng/dl, P < 0.05). Multiple analyses revealed that the TGF beta1 GG genotype of +915 G --> C at codon 25 presented a 3.09 times higher risk in developing AF in the multivariate model after adjusting for age and gender. CONCLUSION: The polymorphisms of TGF beta1 +915 G --> C at codon 25 were associated with occurrence of AF and serum TGF beta1 level in EH subjects.

Association between transforming growth factor beta1 polymorphisms and left ventricle hypertrophy in essential hypertensive subjects.

Left ventricular hypertrophy (LVH) increases the risk of cardiovascular morbid events in hypertension. TGF-beta1 is involved in pathologic states such as cardiac hypertrophy and cardiac fibrosis; we thus postulate that the TGF-beta1 polymorphism is related to LVH in hypertensives. Six hundred and eighty essential hypertensive patients were recruited. Biochemical variables and clinical data were obtained and the determination of LVH was performed by echocardiography. According to the presence of LVH, all subjects were divided into the LVH+ and LVH- group. DNA was obtained, and two coding region polymorphisms of the TGF-beta1 gene (+869 Leu-->Proat codon 10 and +915 ARG-->Pro at codon 25) were analyzed by the polymerase chain reaction. The product was cleaved with the restriction endonucleases. For the polymorphisms of the +869 Leu-->Pro at codon 10, there was no marked difference in the distributions of genotypes and the allele frequencies between the LVH+ and LVH- subjects. For +915 Arg-->Pro at codon 25, a significant difference in the distributions of genotypes of TGF-beta1 was observed. The left ventricular mass index (LVMI) in Arg-Pro genotype carriers was significantly higher than those in the Arg-Arg and Pro-Pro carriers. Multivariate analysis showed that the Arg-Pro genotype was an independent risk factor for LVH (OR 3.23, 95% CI [1.48-5.63, P = 0.002]). The codon 10 genotypes did not show a significant association to LVH. Our data revealed a genetic association of TGF-beta1+915 Arg-->Pro at codon 25 polymorphism with LVH in a Chinese hypertensive population.

Insulin-Like Growth Factor I Prevents Cellular Aging via Activation of Mitophagy.

Mitochondrial dysfunction is a hallmark of cellular aging. Mitophagy is a critical mitochondrial quality control mechanism that removes dysfunctional mitochondria and contributes to cell survival. Insulin-like growth factor 1 (IGF-1) promotes survival of smooth muscle cells (SMCs), but its potential effect on cellular aging is unknown yet. We found that IGF-1 decreased cell senescence, prevented DNA telomere shortening, increased mitochondrial membrane potential, activated cytochrome C oxidase, and reduced mitochondrial DNA damage in long-term cultured (aged) aortic SMC, suggesting an antiaging effect. IGF-1 increased mitophagy in aged cells, and this was associated with decreased expression of cyclin-dependent kinase inhibitors p16 and p21 and elevated levels of Nrf2 and Sirt3, regulators of mitophagy and mitochondrial biogenesis. SiRNA-induced inhibition of either Nrf2 or Sirt3 blocked IGF-1-induced upregulation of mitophagy, suggesting that the Nrf2/Sirt3 pathway was required for IGF-1's effect on mitophagy. PINK1 is a master regulator of mitophagy. PINK1 silencing suppressed mitophagy and inhibited IGF-1-induced antiaging effects in aged SMC, consistent with an essential role of mitophagy in IGF-1's effect on cellular aging. Thus, IGF-1 inhibited cellular aging via Nrf2/Sirt3-dependent activation of mitophagy. Our data suggest that activation of IGF-1 signaling is a novel potential strategy to activate mitophagy and slow cellular aging.

APE1 inhibits foam cell formation from macrophages via LOX1 suppression.

BACKGROUND: Macrophage activation and massive foam cell formation are key events in the development of Atherosclerosis (AS). Apurinic apyrimidinic endonuclease 1/Redox factor-1 (APE1) is an enzyme responsible for DNA repair and redox regulation. Recent studies indicate that APE1 is also involved in inflammatory response. We sought to explore its effect on oxidized low-density lipoprotein (oxLDL) induced macrophage activation and foam cell formation. METHODS: Human macrophage cell line THP-1 cells were cultured and treated with oxLDL. The mRNA and protein levels of inflammatory markers for macrophage activation were measured. Foam cell formation was detected by Oil red O staining. Meanwhile the major cellular receptors responsible for oxLDL uptake and efflux were detected. Chromatin immunoprecipitation-quantitative real time PCR (ChIP-qPCR) and dual luciferase reporter assays were performed to identify the molecular mechanisms through which APE1 affects macrophage activation and foam cell formation. RESULTS: Aberrant APE1 expression dramatically decreases the mRNA and protein of oxLDL-induced inflammatory molecules in THP-1 cells, accompanied by significantly inhibited foam cell formation. Western blot assay showed that down-regulation of LOX1, a receptor of oxLDL, is responsible for the inhibitory effect of APE1 on oxLDL induced macrophage inflammation. ChIP-qPCR assay showed that APE1 inhibits binding of the LOX1 promoter to its transcription factor Oct1, leading to suppression of LOX1. CONCLUSION: Our data confirm the anti-inflammatory properties of APE1 and for the first-time report that APE1 suppresses foam cell formation from macrophages via the oxLDL receptor LOX1. This finding indicates that APE1 can be a therapeutic target for AS prevention.