Calcium Signal Pathway is Involved in Prostaglandin E2 Induced Cardiac Fibrosis in Cardiac Fibroblasts.

Prostaglandin E2 (PGE2), one of the arachidonic acid metabolites synthetized from arachidonic acid through cyclooxygenase (COX) catalysis, demonstrates multiple physiological and pathological actions through different subtypes of EP receptors. PURPOSE: The present study was designed to explore the effects of PGE2 on cardiac fibrosis and the involved mechanism. METHODS: We used western blot analysis, real-time quantitative PCR and immunostaining etc. to testify the mechanism. RESULTS: Our data showed that in cultured adult rat cardiac fibroblasts (CFs), PGE2 effectively promoted the expression of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF)，fibronectin (FN), Collagen I and induced [Ca2+]i increase. Besides, calcium increase evoked by PGE2 is mediated by virtue of EP1 activation. Instead of EP3 or EP4, inhibition of EP1 attenuated PGE2-stimulated upregulation of α-SMA，CTGF, FN, collagen I and [Ca2+]i, as well as the nuclear factor of activated T cell cytoplasmic 4 protein (NFATc4) translocation. CONCLUSIONS: PGE2 may promote cardiac fibrosis via EP1 receptor and calcium signal pathway.

NMNAT3 is involved in the protective effect of SIRT3 in Ang II-induced cardiac hypertrophy.

Pathological cardiac hypertrophy is a maladaptive response in a variety of organic heart disease (OHD), which is characterized by mitochondrial dysfunction that results from disturbed energy metabolism. SIRT3, a mitochondria-localized sirtuin, regulates global mitochondrial lysine acetylation and preserves mitochondrial function. However, the mechanisms by which SIRT3 regulates cardiac hypertrophy remains to be further elucidated. In this study, we firstly demonstrated that expression of SIRT3 was decreased in Angiotension II (Ang II)-treated cardiomyocytes and in hearts of Ang II-induced cardiac hypertrophic mice. In addition, SIRT3 overexpression protected myocytes from hypertrophy, whereas SIRT3 silencing exacerbated Ang II-induced cardiomyocyte hypertrophy. In particular, SIRT3-KO mice exhibited significant cardiac hypertrophy. Mechanistically, we identified NMNAT3 (nicotinamide mononucleotide adenylyltransferase 3), the rate-limiting enzyme for mitochondrial NAD biosynthesis, as a new target and binding partner of SIRT3. Specifically, SIRT3 physically interacts with and deacetylates NMNAT3, thereby enhancing the enzyme activity of NMNAT3 and contributing to SIRT3-mediated anti-hypertrophic effects. Moreover, NMNAT3 regulates the activity of SIRT3 via synthesis of mitochondria NAD. Taken together, these findings provide mechanistic insights into the negative regulatory role of SIRT3 in cardiac hypertrophy.

Store-Operated Ca2+ Entry (SOCE) contributes to angiotensin II-induced cardiac fibrosis in cardiac fibroblasts.

Store-operated Ca2+ entry (SOCE) is an important mechanism of extracellular Ca2+ entry into cells. It has been proved that SOCE is involved in many pathologic and physiological processes. Two key participants of SOCE, stromal interaction molecule1 (STIM1) and Orai1, have been identified. But their function in cardiac fibroblasts remains elusive. In present study, our findings suggested the expression of STIM1 and Orai1 were increased followed by angiotensin II (Ang II) stimulation in vivo and in vitro. In cultured adult rat cardiac fibroblasts, Ang II led to STIM1 interact with Orai1 and Ca2+ release from intracellular calcium store. In addition, the upregulation of fibronectin (FN), connective tissue growth factor (CTGF) and smooth muscle α-actin (α-SMA) induced by Ang II were attenuated by SOCE inhibitor SKF-96365, similar results were observed by knocking down STIM1 and Orai1. Furthermore, we found that silencing Orai1 by RNA interference also suppressed the translocation of Nuclear Factor of Activated T-cells (NFAT) Isoforms NFATc4 and decreased the phosphorylation of Smad2 and Smad3 induced by Ang II. These results unraveled a novel role of SOCE as a key modulator in the Ang II-induced cardiac fibrosis by mediating Ca2+ influx.

Salvianolic acid B protects cardiomyocytes from angiotensin II-induced hypertrophy via inhibition of PARP-1.

Salvianolic acid B (SalB), one of the major bioactive components in Salviamiltiorrhiza, has plenty of cardioprotective effects. The present study was designed to investigate the effect of SalB on angiotensin II (AngII)-induced hypertrophy in neonatal rat cardiomyocytes, and to find out whether or not this effect is attributed to inhibition of poly (ADP-ribose) polymerase-1 (PARP-1), which plays a key role in cardiac hypertrophy. Our results showed that SalB prevented the cardiomyocytes from AngII-induced hypertrophy, associated with attenuation of the mRNA expressions of atrial natriuretic factor and brain natriuretic peptide, and reduction in the cell surface area. SalB inhibited the activity of PARP-1. The inhibitory effect was comparable to that of the PARP-1 inhibitor 3-Aminobenzamide (3-AB). In addition, SalB reversed the depletion of cellular NAD(+) induced by AngII. Moreover, overexpression of PARP-1 attenuated the anti-hypertrophic effect of SalB. These observations suggested that SalB prevented the cardiomyocytes from AngII-induced hypertrophy, at least partially through inhibition of PARP-1. Moreover, SalB attenuated the generation of oxidative stress via suppression of NADPH oxidase 2 and 4, which might probably contribute to the inhibition of PARP-1. These present findings may shed new light on the understanding of the cardioprotective effect of SalB.

SLC41A1 knockdown inhibits angiotensin II-induced cardiac fibrosis by preventing Mg(2+) efflux and Ca(2+) signaling in cardiac fibroblasts.

Na(+)/Mg(2+) exchanger plays an important role in cardiovascular system, but the molecular mechanisms still largely remain unknown. The Solute Carrier family 41A1 (SLC41A1), a novel Mg(2+) transporter, recently was found to function as Na(+)/Mg(2+) exchanger, which mainly regulates the intracellular Mg(2+) ([Mg(2+)]i) homeostasis. Our present studies were designed to investigate whether SLC41A1 impacts on the fibrogenesis of cardiac fibroblasts under Ang II stimulation. Our results showed that quinidine, a prototypical inhibitor of Na(+)/Mg(2+) exchanger, inhibited Ang II-induced cardiac fibrosis via attenuating the overexpression of vital biomarkers of fibrosis, including connective tissue growth factor (CTGF), fibronectin (FN) and α-smooth muscle actin (α-SMA). In addition, quinidine also decreased the Ang II-mediated elevation of concentration of intracellular Ca(2+) ([Ca(2+)]i) and extrusion of intracellular Mg(2+). Meanwhile, silencing SLC41A1 by RNA interference also impaired the elevation of [Ca(2+)]i, [Mg(2+)]i efflux and the upregulation of CTGF, FN and α-SMA provoked by Ang II. Furthermore, we found that Ang II-mediated activation of NFATc4 translocation decreased in SLC41A1-siRNA cells. These results support the notion that rapid extrusion of intracellular Mg(2+) is mediated by SLC41A1 and provide the evidence that the intracellular free Ca(2+) concentration is influenced by extrusion of intracellular Mg(2+) which facilitates fibrosis reaction in cardiac fibroblasts.

Cryptotanshinone attenuates cardiac fibrosis via downregulation of COX-2, NOX-2, and NOX-4.

Cryptotanshinone (CTS), a bioactive constituent extracted from a Chinese traditional herb Danshen (Salvia miltiorrhiza), demonstrates multiple protective effects against cardiovascular diseases. The present study was designed to explore the effects of CTS in vitro by cultured adult rat cardiac fibroblasts stimulated with angiotensin II (Ang II) and in vivo by rats with acute myocardial infarction. Our data showed that in cardiac fibroblasts, CTS attenuated Ang II-induced upregulation of fibronectin, connective tissue growth factor, cyclooxygenase-2, and normalized Ang II-induced upregulation of extracellular signal-regulated kinases 1/2 (ERK1/2). Meanwhile, CTS depressed the Ang II-stimulated upregulation of NAD(P)H oxidase 2 and 4 (NOX-2 and NOX-4) and reactive oxygen species production. Similar results were observed in acute myocardial infarction rats with oral administration of CTS, which relieved the pathological changes accompanying myocardial infarction. In conclusion, CTS may exert antifibrotic effects in vitro by inhibiting Ang II-induced extracellular signal-regulated kinases 1/2 phosphorylation and the expression of cyclooxygenase-2, NOX-2, and NOX-4, and also improved the pathological changes and relieved cardiac fibrosis in vivo.

Transient receptor potential melastatin 7 (TRPM7) contributes to H2O2-induced cardiac fibrosis via mediating Ca(2+) influx and extracellular signal-regulated kinase 1/2 (ERK1/2) activation in cardiac fibroblasts.

Transient receptor potential melastatin 7 (TRPM7), a Ca(2+)-nonselective cation channel, plays a key role in the pathophysiological response of multiple cell types. However, the role of TRPM7 channels in hydrogen peroxide (H2O2)-induced cardiac fibrosis remains unclear. This study aimed to explore whether TRPM7 channels are involved in H2O2-induced cardiac fibrosis and the underlying mechanisms. Our results showed that 2-aminoethoxydiphenylborate (2-APB), which is commonly used to block TRPM7 channels, inhibited H2O2-induced cardiac fibrosis via attenuating the overexpression of important fibrogenic biomarkers and growth factors in cardiac fibroblasts, including collagen type I (Col I), fibronectin (FN), smooth muscle α-actin (α-SMA), connective tissue growth factor (CTGF), and transforming growth factor-ß1 (TGF-ß1). In addition, 2-APB also decreased H2O2-mediated elevation of the concentration of intracellular Ca(2+) ([Ca(2+)]i). Meanwhile, silencing TRPM7 channels by shRNA interference also impaired the increased [Ca(2+)]i and upregulation of Col I, FN, α-SMA, CTGF, and TGF-ß1 induced by H2O2. Furthermore, we found that H2O2-mediated activation of extracellular signal-regulated kinase 1/2 (ERK1/2) decreased in TRPM7-shRNA cells and Ca(2+)-free culture media. These results demonstrated that TRPM7 channels contributed to H2O2-induced cardiac fibrosis and suggested that this contribution may be through mediating Ca(2+) influx and phosphorylation of ERK1/2.

Characteristics of the gut microbiome and metabolic profile in elderly patients with sarcopenia.

Introduction: There is growing evidence of research indicating that the gut microbiota is involved in the development of sarcopenia. Nevertheless, there exists a notable deficiency in comprehension concerning the connection between irregularities in the intestinal microbiome and metabolic processes in older individuals suffering from sarcopenia. Methods: To analyze fecal samples obtained from a cohort of 30 older patients diagnosed with sarcopenia as well as 30 older patients without sarcopenia, this study employed 16S rDNA sequencing and liquid chromatography-mass spectrometry (LC-MS)-based non-targeted metabolomics profiling techniques. Results: As a result, we found that 29 genera and 172 metabolites were significantly altered in the sarcopenic patients. Among them, Blautia, Lachnospiraceae_unclassified, and Subdoligranulum were the bacteria with a potential diagnostic value for sarcopenia diagnosis. Correlation analysis between clinical indices and these gut bacteria suggested that the IL-6 level was negatively correlated with Blautia. Function prediction analysis demonstrated that 17 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways differ significantly between sarcopenic and non-sarcopenic patients. The primary classes of metabolites identified in the study included lipids and lipid-like molecules, organic acids and derivatives, and organoheterocyclic compounds. KEGG enrichment analysis showed that purine metabolism, arginine and proline metabolism, alanine, aspartate, and glutamate metabolism, butanoate metabolism, and histidine metabolism may contribute to the development of sarcopenia. The correlation study on gut microbiota and metabolites found that Lachnospiraceae_unclassified was positively associated with seven metabolites that were more abundant in the non-sarcopenia group and negatively correlated with three metabolites that were more abundant in the sarcopenia group. In addition, Subdoligranulum was positively correlated with seven metabolites that were lacking in sarcopenia and negatively correlated with two metabolites that were enriching in sarcopenia. Moreover, Blautia was positively associated with xanthosine. Discussion: We conducted a study on the intestinal microbiota and metabolic profile of elderly individuals with sarcopenia, offering a comprehensive analysis of the overall ecosystem. Through this investigation, we were able to validate existing research on the gut-muscle axis and further investigate potential pathogenic processes and treatment options for sarcopenia.

ESR1 PvuII (rs2234693 T>C) polymorphism and cancer susceptibility: Evidence from 80 studies.

Emerging epidemiological researches have been performed to assess the association of ESR1 PvuII (rs2234693 T>C) polymorphism with the risk of cancer, yet with conflicting conclusions. Therefore, this updated meta-analysis was performed to make a more accurate evaluation of such relationship. We adopted EMBASE, PubMed, CNKI, and WANFANG database to search relevant literature before January 2018. Odds ratios (ORs) and 95% confidence intervals (CIs) were employed to estimate the relationship strengths. In final, 80 studies (69 publications) involving 26428 cases and 43381 controls were enrolled. Our results failed to provide significant association between overall cancer risk and PvuII polymorphism under homozygous (TT vs. CC) and heterozygous (TT vs. CT) models. Statistically significant relationship was only observed for PvuII polymorphism in allele model T vs. C (OR=0.95, 95% CI=0.91-0.99). Stratification analysis by cancer type suggested that T genotype significantly decreased prostate cancer risk (TT vs. CC: OR=0.79, 95% CI=0.66-0.94; T vs. C: OR=0.89, 95% CI=0.82-0.98), Leiomyoma risk (T vs. C: OR=0.82, 95% CI=0.68-0.98), and HCC risk (TT vs. CC: OR=0.45, 95% CI=0.28-0.71; T vs. C: OR=0.67, 95% CI=0.47-0.95). Furthermore, significantly decreased risk was also found for Africans, population-based and hospital-based studies in the stratified analyses. These results suggest that ESR1 PvuII (rs2234693 T>C) polymorphism may only have little impact on cancer susceptibility. In the future, large-scale epidemical studies are warranted to verify these results.

Inhibitory effect of ethyl acetate extract of Aristolochia yunnanensis on cardiac fibrosis through extracellular signal-regulated kinases 1/2 and transforming growth factor ß/small mother against decapentaplegic signaling pathways.

Aristolochia yunnanensis, known as Nan Mu Xiang in traditional Chinese medicine, has long been used to treat hypertension and chest pain. In this study, the effect of ethyl acetate extract of Nan Mu Xiang (NMX) on cardiac fibrosis was assessed in vitro by cultured adult rat cardiac fibroblasts with angiotensin II (AngII) stimulation, and in vivo by rats with abdominal aorta constriction (AAC). In cultured adult rat cardiac fibroblasts stimulated by AngII, NMX inhibited cardiac fibroblast proliferation, reduced the expression of fibronectin, α-smooth muscle actin (α-SMA), and transforming growth factor ß (TGF-ß) in a dose-dependent manner; and suppressed AngII-induced phosphorylation of extracellular signal-regulated kinase (ERK)1/2, C- rapidly accelerated fibrosarcoma (C-Raf), and small mother against decapentaplegic (Smad) 2. Similar results were also observed in AAC rats with intraperitoneal injection of NMX, which not only ameliorated myocardial fibrosis, but also improved cardiac function. The therapeutic effect of NMX on myocardial fibrosis is attributed mainly to the inhibition of ERK and the TGF-ß/Smad signaling pathways. NMX may be a promising potential drug candidate for myocardial fibrosis.

(E)-1-(4-ethoxyphenyl)-3-(4-nitrophenyl)-prop-2-en-1-one suppresses LPS-induced inflammatory response through inhibition of NF-κB signaling pathway.

Flavonoids are a class of compounds that exist in nature with the structure of 2-phenyl-chromone. In Chinese traditional medicine, herbal drugs containing flavonoids are widely used for the treatment of inflammation, cardiovascular disease, tumor and so on. In this study, we investigated the anti-inflammatory effect and related mechanisms of a novel synthetic flavonoid, (E)-1-(4-ethoxyphenyl)-3-(4-nitrophenyl)-prop-2-en-1-one (ETH) in lipopolysaccharide (LPS) stimulated macrophages. Our results showed that ETH inhibited LPS-induced TNF-α and IL-6 release in a dose-dependent manner, and decreased TNF-α, IL-1ß, IL-6 and iNOS mRNA production. LPS-induced expression of cyclooxygenase-2 (COX-2) was also significantly attenuated by ETH. Pretreatment with ETH reduced the I-κBα phosphorylation, p65 nuclear translocation as well as NF-κB-dependent transcriptional activity. In addition, ETH exhibited a significant protection against LPS-induced inflammatory mortality in mice. Taken together, these findings suggest that ETH can inhibit LPS-induced inflammation via suppressing NF-κB signaling pathway, indicating that ETH may be a potential anti-inflammatory agent.

Biomimetic mineralization of calcium carbonate/carboxymethylcellulose microspheres for lysozyme immobilization.

Porous calcium carbonate/carboxymethylcellulose (CaCO3/CMC) microspheres were prepared by the biomimetic mineralization method for lysozyme immobilization via adsorption. The size and morphology of CaCO3/CMC microspheres were characterized by transmitted electron microscopy (TEM) and zeta potential measurement. The lysozyme immobilization was verified by Fourier transform infrared (FTIR) spectroscopy. The effects of pHs and temperatures on lysozyme adsorption were investigated as well. It was revealed that CaCO3/CMC microspheres could immobilize lysozyme efficiently via electrostatic interactions and a maximum adsorption capacity of 450mg/g was achieved at pH 9.2 and 25°C. Moreover, it was found that the adsorption process fitted well with the Langmuir isothermal model. In addition, UV, fluorescence, and circular dichroism (CD) spectroscopic studies showed that lysozyme maintained its original secondary structure during the adsorption/desorption process. Our study therefore demonstrated that CaCO3/CMC microsphere can be used as a cost-effective and efficient support for lysozyme immobilization.