SLC44A2 regulates vascular smooth muscle cell phenotypic switching and aortic aneurysm.

Aortic aneurysm is a life-threatening disease with limited interventions, closely related to vascular smooth muscle cells (VSMCs) phenotypic switching. SLC44A2, a member of solute carrier series 44 (SLC44) family, remains under-characterized in the context of cardiovascular diseases. Venn diagram analysis based on microarray and single-cell RNA sequencing identified SLC44A2 as a major regulator of VSMCs phenotypic switching in aortic aneurysm. Screening for Slc44a2 amongst aortic cell lineages demonstrated its predominant location in VSMCs. Elevated levels of SLC44A2 were evidenced in the aorta of both abdominal aortic aneurysm patients and angiotensin II (Ang II)-infused Apoe-/- mice. In vitro, SLC44A2 silencing promoted VSMCs towards a synthetic phenotype, while SLC44A2 overexpression attenuated VSMCs phenotypic switching. VSMCs-specific SLC44A2 knockout mice were more susceptible to aortic aneurysm under Ang II infusion, while SLC44A2 overexpression showed protective effects. Mechanistically, SLC44A2 interaction with NRP1 and ITGB3 activates TGF-ß/SMAD signaling, thereby promoting contractile genes expression. Elevated SLC44A2 in aortic aneurysm is associated with upregulated runt-related transcription factor 1 (RUNX1). Furthermore, low dose of lenalidomide (LEN) suppressed aortic aneurysm progression by enhancing SLC44A2 expression. These findings reveal SLC44A2/NRP1/ITGB3 complex is a major regulator of VSMCs phenotypic switching and provide potential therapeutic approach (LEN) for aortic aneurysm treatment.

Apigenin alleviates doxorubicin-induced myocardial pyroptosis by inhibiting glycogen synthase kinase-3ß in vitro and in vivo.

Apigenin, a natural flavonoid compound found in chamomile (Matricaia chamomilla L.) from the Asteraceae family, has been shown in our previous study to possess antimyocardial hypertrophy and anti-cardiac fibrosis effects. However, its effects and mechanisms on the pyroptosis of cardiomyocytes induced by doxorubicin (DOX) are poorly understood. The objective of this study was to investigate the role of GSK-3ß and the effects of apigenin in DOX-induced cardiotoxicity. H9c2 cells stimulated with DOX were treated with SB216763 and apigenin. Additionally, a mouse model of DOX-induced cardiotoxicity was prepared and further treated with apigenin and SB216763 for 30 days. The findings revealed that treatment with SB216763 or apigenin resulted in a significant reduction in the levels of pyroptosis-related factors. Furthermore, the phosphorylation of GSK-3ß was enhanced while the phosphorylation of nuclear factor-kB (NF-κB) p65 was reduced following treatment with either SB216763 or apigenin. Conversely, the effects of apigenin treatment were nullified in siRNA-GSK-3ß-transfected cells. Results from computer simulation and molecular docking analysis supported that apigenin could directly target the regulation of GSK-3ß. Therefore, our study confirmed that the inhibition of GSK-3ß and treatment with apigenin effectively suppressed the pyroptosis of cardiomyocytes in both DOX-stimulated H9c2 cells and mice. These benefits may be attributed in part to the decrease in GSK-3ß expression and subsequent reduction in NF-κB p65 activation. Overall, our findings revealed that the pharmacological targeting of GSK-3ß may offer a promising therapeutic approach for alleviating DOX-induced cardiotoxicity.

Estrogen inhibits TGF­ß1­stimulated cardiac fibroblast differentiation and collagen synthesis by promoting Cdc42.

17ß­estradiol (E2) can inhibit cardiac fibrosis in female patients with heart failure (HF) and activate cell division cycle 42 (Cdc42), however it is unknown whether 17ß­estradiol (E2) can ameliorate differentiation and collagen synthesis in TGF­ß1­stimulated mouse cardiac fibroblasts (MCFs) by regulating cell division cycle 42 (Cdc42). The present study aimed to investigate the roles of estrogen and Cdc42 in preventing myocardial fibrosis and the underlying molecular mechanisms. An ELISA was used to measure the levels of E2 and Cdc42 in the serum of patients with heart failure (HF), and western blotting was used to measure the expression levels of Cdc42 in TGF­ß1­stimulated immortalized MCFs. MCFs were transfected with a Cdc42 overexpression (OE) lentivirus or small interfering RNA (siRNA), or treated with a Cdc42 inhibitor (MLS­573151), and the function of Cdc42 was assessed by western blotting, immunofluorescence staining, reverse transcription­quantitative PCR and dual­luciferase reporter assays. Western blotting and immunofluorescence staining were performed to verify the protective effect of E2 on TGF­ß1­stimulated MCFs, and the association between the protective effect and Cdc42. The results demonstrated that Cdc42 levels were increased in the serum of patients with HF and were positively correlated with the levels of E2; however, Cdc42 levels were decreased in TGF­ß1­stimulated MCFs. Cdc42 inhibited MCF differentiation and collagen synthesis, as indicated by the protein expression of α­smooth muscle actin, collagen I and collagen III. Mechanistically, Cdc42 inhibited the transcription of TGF­ß1 by promoting the expression of p21 (RAC1)­activated kinase 1 (Pak1)/JNK/c­Jun signaling pathway proteins and inhibiting the activity of the Tgfb1 gene promoter. In addition, E2 inhibited the differentiation and collagen synthesis of TGF­ß1­stimulated MCFs, and promoted the protein expression of Pak1, JNK and c­Jun, consistent with the effects of Cdc42, whereas the effects of E2 were abolished when Cdc42 was knocked down. The aforementioned findings suggested that E2 could inhibit differentiation and collagen synthesis in TGF­ß1­stimulated MCFs by regulating Cdc42 and the downstream Pak1/JNK/c­Jun signaling pathway.

Nonlinear Relationship Between Systemic Immune-Inflammation and Hepatic Steatosis: A Population-Based Study in China.

Background: Studies on the associations between Systemic Immune-Inflammation (SII) and hepatic steatosis in China are still lacking. It is necessary to clarify the relationship between SII and hepatic steatosis in the Chinese population. Methods: This study was conducted from January 2022 to December 2022. A total of 37,095 participants were enrolled, among them, with 20,709 (55.83%) being males, and 16,386 (44.17%) being females. Physical and biochemical indicators were measured during a morning health examination after the examinees had fasted overnight. Diagnoses of hepatic steatosis were determined using an ultrasound test in accordance with the Chinese Guideline. Analysis of variance and chi-square tests were used to analyze the association between SII and hepatic steatosis. Stratification analyses were conducted based on age, gender, and obese status. Restricted cubic spline regression was also performed to explore the shapes of associations between SII and hepatic steatosis. Results: The average age of the 37,095 participants was 44.78 years old, with those with hepatic steatosis (11,599 (31.27%)) averaging 47.06 years old and those (25,496 (68.73%)) in the control group averaging 43.73 years old. SII was positively associated with hepatic steatosis. This association remained significant after conducting stratification analysis by age and gender. The inflection points in the inverted U-shaped curve for the relationship between SII and hepatic steatosis were 399.78 for gender (1000 cells /µL)(nonlinear P<0.01, OR=1.31 (male), 1.00 (female)) and 385.79 for age (1000 cells /µL)(nonlinear P<0.01, OR=1.35 (18~44 years old), 1.87 (45~59 years old), 1.93 (60~ years old)). Conclusion: SII is an independent risk factor for hepatic steatosis, and this effect appears to be stronger in subjects with BMI <28 kg/m2. The nonlinear relationship between SII and hepatic steatosis, characterized by an inverted U-shaped distribution, may serve as a reference for diagnosing and evaluating hepatic steatosis.

Gender differences in the association between healthy eating index-2015 and hypertension in the US population: evidence from NHANES 1999-2018.

BACKGROUND: Diet has long been recognized as an important modifiable risk factor for hypertension. Herein, our research goal was to decipher the association of healthy eating index-2015 (HEI-2015) with hypertension, and to explore potential gender differences. METHODS: We collected the cross-sectional data of 42,391 participants of the National Health and Nutrition Examination Survey (NHANES) 1999-2018. The association of HEI-2015 with hypertension was estimated using weighted multivariate logistic regression, with restricted cubic spline (RCS) regression being adopted to examine the nonlinearity of this association in both genders, and the stability of the results were examined by sensitivity analysis. We also performed subgroup analysis to detect potential difference in the link between HEI-2015 and hypertension stratified by several confounding factors. RESULTS: After eliminating potential confounding bias, the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for hypertension across higher HEI-2015 quartiles were 0.93 (0.85-1.03), 0.84 (0.77-0.93), and 0.78 (0.72-0.86) compared to the lowest quartile, respectively. HEI-2015 was nonlinearly and inversely associated with hypertension in all participants. The gender-specific RCS curves presented a U-shaped correlation in males, while showed a linear and inverse correlation in females. Besides, subgroup analyses showed a lower risk of hypertension in participants who were females, younger than 40 years, Whites, obese, and diabetic patients. CONCLUSIONS: We determined a nonlinear and inverse association between HEI-2015 and hypertension in the US general population, and revealed a remarkable gender difference when adhering to a HEI-2015 diet for preventing hypertension.

Associations of dietary advanced glycation end products with liver steatosis via vibration controlled transient elastography in the United States: a nationwide cross-sectional study.

PURPOSE: Large population-based studies for the associations between dietary advanced glycation end products (dAGEs) intake and liver steatosis remain lacking. It is necessary to clarify the relationship of dAGEsintake with liver steatosis through the National Health and Nutrition Survey (NHANES). METHODS: A total of 5856 participants in the NHANES 2017-2018 were included. The dietary AGEs intake, including ε-(carboxymethyl)lysine(CML), Nε-(1-carboxyethyl)lysine (CEL), and Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were estimated using the combination of ultra-performance LC-tandem MS dietary AGEs database and two 24-h dietary recall interviews. Liver steatosis was assessed by controlled attenuation parameter via transient elastography. Logistic regression model was adopted to explore the relationships between dAGEs intake and hepatic steatosis. RESULTS: Compared with individuals of total dAGEs, CML, MG-H1 in the lowest tertile, those in the highest tertile had highest risk of hepatic steatosis, and the corresponding odds radios(ORs) (95% confidence interval(CI)) were 1.37 (1.01, 1.84), 1.36 (1.04,1.78) and 1.40 (1.06, 1.85), respectively. Subgroups analysis found that the positive association between dAGEs, CML, CEL and MG-H1 and hepatic steatosis appeared stronger in subjects with obesity and those with abnormal waist circumference (WC). CONCLUSION: There was a positive correlation between dAGEs, CML, MG-H1, and hepatic steatosis, and this association mainly existed in subjects with obesity and those with abnormal WC. Dietary AGEs restriction might be of high priority for subjects with obesity for the prevention of fatty liver disease. Further longitudinal studies are required to confirm the causal associations and explore the potential mechanisms.

Exogenous NADPH exerts a positive inotropic effect and enhances energy metabolism via SIRT3 in pathological cardiac hypertrophy and heart failure.

BACKGROUND: Therapies are urgently required to ameliorate pathological cardiac hypertrophy and enhance cardiac function in heart failure. Our preliminary experiments have demonstrated that exogenous NADPH exhibits a positive inotropic effect on isolated heart. This study aims to investigate the positive inotropic effects of NADPH in pathological cardiac hypertrophy and heart failure, as well as the underlying mechanisms involved. METHODS: Endogenous plasma NADPH contents were determined in patients with chronic heart failure and control adults. The positive inotropic effects of NADPH were investigated in isolated toad heart or rat heart. The effects of NADPH were investigated in isoproterenol (ISO)-induced cardiac hypertrophy or transverse aortic constriction (TAC)-induced heart failure. The underlying mechanisms of NADPH were studied using SIRT3 knockout mice, echocardiography, Western blotting, transmission electron microscopy, and immunoprecipitation. FINDINGS: The endogenous NADPH content in the blood of patients and animals with pathological cardiac hypertrophy or heart failure was significantly reduced compared with age-sex matched control subjects. Exogenous NADPH showed positive inotropic effects on the isolated normal and failing hearts, while antagonism of ATP receptor partially abolished the positive inotropic effect of NADPH. Exogenous NADPH administration significantly reduced heart weight indices, and improved cardiac function in the mice with pathological cardiac hypertrophy or heart failure. NADPH increased SIRT3 expression and activity, deacetylated target proteins, improved mitochondrial function and facilitated ATP production in the hypertrophic myocardium. Importantly, inhibition of SIRT3 abolished the positive inotropic effect of NADPH, and the anti-heart failure effect of NADPH was significantly reduced in the SIRT3 Knockout mice. INTERPRETATION: Exogenous NADPH shows positive inotropic effect and improves energy metabolism via SIRT3 in pathological cardiac hypertrophy and heart failure. NADPH thus may be one of the potential candidates for the treatment of pathological cardiac hypertrophy or heart failure. FUNDING: This work was supported by grants from the National Natural Science Foundation of China (No. 81973315, 82173811, 81730092), Natural Science Foundation of Jiangsu Higher Education (20KJA310008), Jiangsu Key Laboratory of Neuropsychiatric Diseases (BM2013003) and the Priority Academic Program Development of the Jiangsu Higher Education Institutes (PAPD).

FGF21 protects against doxorubicin-induced cardiotoxicity by inhibiting connexin 43 ubiquitination.

BACKGROUND: Fibroblast growth factor 21 (FGF21) regulates glycolipid metabolism and insulin homeostasis and acts as a cardioprotective factor by protecting against myocardial ischemia/reperfusion injury, hypertension, and vascular dysfunction. FGF21 has been reported to prevent Doxorubicin (Dox)-induced cardiotoxicity, and the related signaling pathway is worthy of further study. Connexin43 (Cx43) protein was reduced by Dox treatment, especially low phosphorylated form of Cx43. Thus the aim of study is to explore the protection effect of FGF21 on Dox induced cardiotoxicity by improving the expression of Cx43 and the involved signaling pathway. METHODS AND RESULTS: FGF21 inhibited apoptosis in Dox-treated mice and cardiomyocytes. FGF21 increased the levels of connexin43 phosphorylated at serine (S) 282 (p-Cx43 S282) and total Cx43 to inhibit Dox-induced apoptosis. By RNA sequencing, we found that deubiquitinase monocyte chemoattractant protein-induced protein 1 (MCPIP1) expression was increased by FGF21. We further found that FGF21 induced the phosphorylation of fibroblast growth factor receptor 1 (FGFR1), extracellular signal-regulated kinase 1 and 2 (Erk1/2), and Elk. Phosphorylated Elk translocated to the nucleus and increased the expression of MCPIP1. Then, MCPIP1 bound neural precursor cell expressed developmentally downregulated protein 4 (Nedd4), an E3 ubiquitination ligase, as shown by co-immunoprecipitation (Co-IP), and suppressed Cx43 ubiquitination and degradation, competitively inhibiting the binding of Cx43 with Nedd4. Thus Nedd4 could not bind and ubiquitinate Cx43, leading to the up-regulation of Cx43 and phosphorylation of Cx43 at S282. CONCLUSIONS: FGF21 inhibited the effects of Dox on cardiomyocytes by elevating the phosphorylation of Cx43 at S282 and total Cx43 expression. This study suggests a previously unknown mechanism for the FGF21-mediated enhancement of cardiomyocyte survival and provides an effective approach to protect against the adverse cardiac effects of Dox.

Expression and diagnostic value of PIWI-interacting RNA by serum in acute myocardial infarction.

OBJECTIVE: To detect the expression level of PIWI-interacting RNA in the serum of patients with acute myocardial infarction, and to explore the role of PIWI-interacting RNA in acute myocardial infarction. METHODS: RNA was extracted from the serum of acute myocardial infarction patients and healthy subjects, and high-throughput sequencing of PIWI-interacting RNAs was performed to screen differentially expressed PIWI-interacting RNAs. Quantitative polymerase chain reaction was used to detect the expression of four differentially expressed PIWI-interacting RNAs in 52 patients with acute myocardial infarction and 30 healthy people. Receiver operating characteristic (ROC) curve was further used to analyze the correlation between differentially expressed PIWI-interacting RNAs and the occurrence of acute myocardial infarction. Kyoto Encyclopedia of Genes and Genomes analysis was used to analyze the role of PIWI-interacting RNA in the occurrence of acute myocardial infarction. RESULTS: RNA sequencing and bioinformatics analysis revealed that most piRNAs were upregulated in AMI patients, with 195 upregulated and 13 downregulated. Among them, piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction, but their expression in the acute heart failure group and coronary heart disease group was not significantly different from that in the healthy group. ROC curve analysis showed that piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 had high diagnostic values in acute myocardial infarction. In vitro, there was no significant difference in the expression of piR-hsa-9010 among THP-1, HUVEC, and AC16, while the expression of piR-hsa-28646 and piR-hsa-23619 in HUVEC was significantly higher than that in THP-1 and AC16. Pathway analysis showed that piR-hsa-23619 was mainly involved in TNF signaling pathway, and piR-hsa-28646 was mainly involved in Wnt signaling pathway. CONCLUSION: piR-hsa-9010, piR-hsa-28646, and piR-hsa-23619 were significantly up-regulated in the serum of patients with acute myocardial infarction. It can be used as a new biomarker for the diagnosis of acute myocardial infarction, which may be a therapeutic target for acute myocardial infarction.

PiRNA in Cardiovascular Disease: Focus on Cardiac Remodeling and Cardiac Protection.

Cardiovascular diseases (CVDs) are common causes of death, which take about 18.6 million lives worldwide every year. Currently, exploring strategies that delay ventricular remodeling, reduce cardiomyocyte death, and promote cardiomyocyte regeneration has been the hotspot and difficulty of the ischemic heart disease (IHD) research field. Previous studies indicate that piwi-interacting RNA (piRNA) plays a vital role in the occurrence and development of cardiac remodeling and may offer novel therapeutic strategies for cardiac repair. The best-known biological function of piRNA is to silence transposons in cells. In the cardiovascular system, piRNA is known to participate in cardiac progenitor cell proliferation, AKT pathway regulation, and cardiac remodeling and decompensation. In this review, we systematically discuss the research progress on piRNA in CVDs, especially the mechanism of cardiac remodeling and the potential functions in cardiac protection, which provides new insights for the progress and treatment of cardiovascular diseases. Piwi-interacting RNA (piRNA) is one of the noncoding RNAs, with the best -known biological function to silence transposons in cells. Now piRNA is found to participate in cardiac progenitor cell proliferation, AKT pathway regulation, cardiac remodeling and decompensation, which implies the potential of piRNA in the diagnosis and treatment of cardiovascular diseases. Over expression of piRNA could promote cardiac apoptosis and cardiac hypertrophy, thus targeted therapy which inhibits expression of associated piRNA may reduce cardiac remodeling and reduce inflammation caused by necrotic cardiomyocytes. PiRNA is also speculated to participate in the proliferation of cardiac progenitor cells, implying the potential to induce cardiac regeneration th erapy, which provides new insights for treatment of cardiovascular diseases. At present, the treatment strategy of cardiac remodeling emphasizes the control of risk factors, prevention of disease progression and individualized treatment. With further studies in mechanism of piRNA, potential therapies above may come true and more therapies in cardiovascular diseases may be found.

Therapeutic effects on the development of heart failure with preserved ejection fraction by the sodium-glucose cotransporter 2 inhibitor dapagliflozin in type 2 diabetes.

BACKGROUND: Heart failure with preserved ejection fraction (HFpEF) is a common disease with high morbidity and lacks effective treatment. We investigated the protective effects of the long-term application of the sodium-glucose cotransporter 2 inhibitor (SGLT2i) dapagliflozin on diabetes-associated HFpEF in a rat model. Serum proteomics and metabolomics analysis were also conducted in type 2 diabetic patients with HFpEF treated with dapagliflozin. METHODS: Male Zucker diabetic fatty (ZDF) rats were used as a model of diabetic cardiomyopathy. From weeks 16 to 28, animals were given a vehicle or dapagliflozin (1 mg/kg) once daily. Primary blood biochemistry indices, echocardiography, histopathology, and cardiac hemodynamics were determined during the study period. The key markers of myocardial fibrosis, nitro-oxidative stress, inflammation, apoptosis, autophagy, and AMPK/mTOR signaling were examined. Additionally, healthy controls and individuals with type 2 diabetes were enrolled and 16 serum samples from 4 groups were randomly selected. Serum proteome and metabolome changes after dapagliflozin treatment were analyzed in diabetic individuals with HFpEF. RESULTS: Dapagliflozin effectively prevented the development of HFpEF in rats with diabetes by mitigating nitro-oxidative stress, pro-inflammatory cytokines, myocardial hypertrophy, and fibrosis, reducing apoptosis, and restoring autophagy through AMPK activating and mTOR pathway repressing. Proteomics and metabolomics revealed that cholesterol and high-density lipoprotein particle metabolism, nicotinate and nicotinamide metabolism, arginine biosynthesis, and cAMP and peroxisome proliferator-activated receptor (PPAR) signaling are the major disturbed pathways in HFpEF patients treated with dapagliflozin. CONCLUSION: Long-term treatment with dapagliflozin significantly prevented the development of HFpEF in diabetic rats. Dapagliflozin could be a promising therapeutic strategy in managing HFpEF individuals with type 2 diabetes.

Global Profile of tRNA-Derived Small RNAs in Pathological Cardiac Hypertrophy Plasma and Identification of tRF-21-NB8PLML3E as a New Hypertrophy Marker.

BACKGROUND: It remains unclear whether transfer RNA-derived small RNAs (tsRNAs) play a role in pathological cardiac hypertrophy (PCH). We aimed to clarify the expression profile of tsRNAs and disclose their relationship with the clinical phenotype of PCH and the putative role. METHODS: Small RNA sequencing was performed on the plasma of PCH patients and healthy volunteers. In the larger sample size and angiotensin II (Ang II)-stimulated H9c2 cells, the data were validated by real-time qPCR. Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were examined in Ang II-stimulated H9c2 cells. The potential role of tsRNAs in the pathogenesis of PCH was explored by bioinformatics analysis. RESULTS: A total of 4185 differentially expressed tsRNAs were identified, of which four and five tsRNAs were observed to be significantly upregulated and downregulated, respectively. Of the five downregulated tsRNAs, four were verified to be significantly downregulated in the larger sample group, including tRF-30-3JVIJMRPFQ5D, tRF-16-R29P4PE, tRF-21-NB8PLML3E, and tRF-21-SWRYVMMV0, and the AUC values for diagnosis of concentric hypertrophy were 0.7893, 0.7825, 0.8475, and 0.8825, respectively. The four downregulated tsRNAs were negatively correlated with the left ventricular posterior wall dimensions in PCH patients (r = -0.4227; r = -0.4517; r = -0.5567; r = -0.4223). The levels of ANP and BNP, as well as cell size, were decreased in Ang II-stimulated H9c2 cells with 21-NB8PLML3E mimic transfection. Bioinformatics analysis revealed that the target genes of tRF-21-NB8PLML3E were mainly enriched in the metabolic pathway and involved in the regulation of ribosomes. CONCLUSIONS: The plasma tRF-21-NB8PLML3E might be considered as a biomarker and offers early screening potential in patients with PCH.

Cathepsin B S-nitrosylation promotes ADAR1-mediated editing of its own mRNA transcript via an ADD1/MATR3 regulatory axis.

Genetic information is generally transferred from RNA to protein according to the classic "Central Dogma". Here, we made a striking discovery that post-translational modification of a protein specifically regulates the editing of its own mRNA. We show that S-nitrosylation of cathepsin B (CTSB) exclusively alters the adenosine-to-inosine (A-to-I) editing of its own mRNA. Mechanistically, CTSB S-nitrosylation promotes the dephosphorylation and nuclear translocation of ADD1, leading to the recruitment of MATR3 and ADAR1 to CTSB mRNA. ADAR1-mediated A-to-I RNA editing enables the binding of HuR to CTSB mRNA, resulting in increased CTSB mRNA stability and subsequently higher steady-state levels of CTSB protein. Together, we uncovered a unique feedforward mechanism of protein expression regulation mediated by the ADD1/MATR3/ADAR1 regulatory axis. Our study demonstrates a novel reverse flow of information from the post-translational modification of a protein back to the post-transcriptional regulation of its own mRNA precursor. We coined this process as "Protein-directed EDiting of its Own mRNA by ADAR1 (PEDORA)" and suggest that this constitutes an additional layer of protein expression control. "PEDORA" could represent a currently hidden mechanism in eukaryotic gene expression regulation.

Isorhapontigenin Attenuates Cardiac Microvascular Injury in Diabetes via the Inhibition of Mitochondria-Associated Ferroptosis Through PRDX2-MFN2-ACSL4 Pathways.

Ferroptosis is a newly identified form of regulated cell death that is driven by iron overload and uncontrolled lipid peroxidation, but the role of ferroptosis in cardiac microvascular dysfunction remains unclear. Isorhapontigenin (ISO) is an analog of resveratrol and possesses strong antioxidant capacity and cardiovascular-protective effects. Moreover, ISO has been shown to alleviate iron-induced oxidative damage and lipid peroxidation in mitochondria. Therefore, the current study aimed to explore the benefits of ISO treatment on cardiac microvascular dysfunction in diabetes and the possible mechanisms involved, with a focus on ferroptosis and mitochondria. Our data revealed that ISO treatment improved microvascular density and perfusion in db/db mice by mitigating vascular structural damage, normalizing nitric oxide (NO) production via endothelial NO synthase activation, and enhancing angiogenetic ability via vascular endothelial growth factor receptor 2 phosphorylation. PRDX2 was identified as a downstream target of ISO, and endothelial-specific overexpression of PRDX2 exerted effects on the cardiac microvascular function that were similar to those of ISO treatment. In addition, PRDX2 mediated the inhibitive effects of ISO treatment on ferroptosis by suppressing oxidative stress, iron overload, and lipid peroxidation. Further study suggested that mitochondrial dynamics and dysfunction contributed to ferroptosis, and ISO treatment or PRDX2 overexpression attenuated mitochondrial dysfunction via MFN2-dependent mitochondrial dynamics. Moreover, MFN2 overexpression suppressed the mitochondrial translocation of ACSL4, ultimately inhibiting mitochondria-associated ferroptosis. In contrast, enhancing mitochondria-associated ferroptosis via ACSL4 abolished the protective effects of ISO treatment on cardiac microcirculation. Taken together, the results of the present work demonstrated the beneficial effects of ISO treatment on cardiac microvascular protection in diabetes by suppressing mitochondria-associated ferroptosis through PRDX2-MFN2-ACSL4 pathways.

Update on gut microbiota in cardiovascular diseases.

In recent years, due to the development and widespread utilization of metagenomic sequencing and metabolomics, the relationship between gut microbiota and human cardiovascular diseases (CVDs) has received extensive attention. A growing number of studies have shown a strong relationship between gut microbiota and CVDs, such as coronary atherosclerosis, hypertension (HTN) and heart failure (HF). It has also been revealed that intestinal flora-related metabolites, such as trimethylamine-N-oxide (TMAO), short-chain fatty acids (SCFA) and bile acids (BAs), are also related to the development, prevention, treatment and prognosis of CVDs. In this review, we presented and summarized the recent findings on the relationship between gut microbiota and CVDs, and concluded several currently known gut microbiota-related metabolites and the occurrence and development of CVDs.

Apigenin inhibits isoproterenol-induced myocardial fibrosis and Smad pathway in mice by regulating oxidative stress and miR-122-5p/155-5p expressions.

Apigenin, a flavonoid isolated from Apium graveolens, is an effective natural active ingredient that inhibits transforming growth factor-ß1 (TGF-ß1)-induced cardiac fibroblasts (CFs) differentiation and collagen synthesis. However, its effects on isoproterenol-induced myocardial fibrosis in mice remain unknown. This study aimed to examine the effect of apigenin in the prevention of myocardial fibrosis. A mouse model of myocardial fibrosis induced by isoproterenol was established, and the mice were given apigenin 75-300 mg/kg orally for 40 days. The results showed that the heart weight coefficient, myocardial hydroxyproline, collagen accumulation, and malondialdehyde levels in the apigenin-treated groups were significantly reduced. In contrast, the activity of myocardial superoxide dismutase and glutathione peroxidase were significantly enhanced. The results of real-time quantitative polymerase chain reaction and western blot assays showed that apigenin could significantly upregulate the expressions of myocardial microRNA-122-5p (miR-122-5p), c-Ski, and Smad7 and downregulate the expressions of myocardial miR-155-5p, α-smooth muscle actin, collagen I/III, NF-κB, TGF-ß1, hypoxia-inducible factor-1α (HIF-1α), Smad2/3, and p-Smad2/3. In vitro, the differentiation and extracellular matrix production, as well as TGF-ß1/Smads axis, were further reduced after treatment of miR-122-5p mimic or miR-155-5p inhibitor-transfected and TGF-ß1-stimulated CFs with apigenin. These results suggested that apigenin increased the expression of miR-122-5p and decreased the expression of miR-155-5p, which subsequently downregulated and upregulated the target genes HIF-1α and c-Ski, respectively. Furthermore, apigenin administration downregulated TGF-ß1-induced Smad2/3 and upregulated Smad7. In addition, it reduced the NF-κB/TGF-ß1 signaling pathway axis by increasing antioxidant ability to exert the antifibrotic effects.

Long noncoding RNA uc003pxg.1 regulates endothelial cell proliferation and migration via miR­25­5p in coronary artery disease.

Long noncoding RNAs (lncRNAs) have been reported to be associated with the progression of coronary artery disease (CAD). In our previous study, the levels of lncRNA uc003pxg.1 were upregulated in patients with CAD compared with those in control subjects. However, the role and underlying mechanism of the effects of uc003pxg.1 in CAD remain unknown. Therefore, the aim of the present study was to investigate the expression pattern and biological function of uc003pxg.1 in CAD. First, uc003pxg.1 expression levels were assessed in peripheral blood mononuclear cells isolated from patients with CAD by reverse transcription­quantitative (RT­q)PCR. The results demonstrated that the levels of uc003pxg.1 were significantly upregulated (~4.6­fold) in samples from 80 patients with CAD compared with those in 80 healthy subjects. Subsequently, the present study demonstrated that small interfering RNA­mediated uc003pxg.1 knockdown inhibited human umbilical vein endothelial cell (HUVEC) proliferation and migration, which was analyzed using the Cell Counting Kit­8, cell cycle, EdU and Transwell assays. Additionally, the results of RT­qPCR and western blot analyses revealed that uc003pxg.1 regulated the mRNA and protein levels of cyclin D1 and cyclin­dependent kinase. Through high­throughput sequencing and dual­luciferase reporter assays, the present study demonstrated that microRNA (miR)­25­5p was a downstream target of uc003pxg.1. Further experiments verified that uc003pxg.1 regulated HUVEC proliferation and migration via miR­25­5p. The results of the present study may enhance the current understanding of the role of lncRNA uc003pxg.1 in CAD.

hAECs and their exosomes improve cardiac function after acute myocardial infarction in rats.

BACKGROUND: Human amniotic epithelial cells (hAECs) are seed cells used to treat acute myocardial infarction (AMI), but their mechanism remains unclear. METHODS: We cultured hAECs and extracted exosomes from culture supernatants. Next, we established a stable AMI model in rats and treated them with hAECs, exosomes, or PBS. We assess cardiac function after treatment by echocardiography. Additionally, heart tissues were collected and analyzed by Masson's trichrome staining. We conducted the tube formation and apoptosis assays to explore the potential mechanisms. RESULTS: Cardiac function was improved, and tissue fibrosis was decreased following implantation of hAECs and their exosomes. Echocardiography showed that the EF and FS were lower in the control group than in the hAEC and exosome groups, and that the LVEDD and LVESD were higher in the control group (P<0.05). Masson's trichrome staining showed that the fibrotic area was larger in the control group. Tube formation was more efficient in the hAEC and exosome groups (P<0.0001). Additionally, the apoptosis rates of myocardial cells in the hAEC and exosome groups were significantly decreased (P<0.0001). CONCLUSIONS: hAECs and their exosomes improved the cardiac function of rats after AMI by promoting angiogenesis and reducing the apoptosis of cardiac myocytes.

Association of serum Cyr61 levels with peripheral arterial disease in subjects with type 2 diabetes.

BACKGROUND: The prevalence of peripheral artery disease (PAD) is obviously increased in patients with diabetes. Existing evidence shows that cysteine-rich angiogenic inducer 61 (Cyr61), a 40-kD secreted protein, plays important roles in regulating cellular physiological processes. Recent studies have demonstrated a significant correlation between serum Cyr61 and atherosclerosis. However, the relationship between Cyr61 levels and PAD in patients with type 2 diabetes (T2DM) remains obscure. METHODS: Data from a total of 306 subjects with T2DM were cross-sectionally analysed. The extent of PAD was determined by using the Fontaine classification, which defines four stages. We measured serum Cyr61 concentrations by ELISA in subjects with and without PAD at Fontaine's stage II, III, or IV. Logistic regression models were used to examine the independent association of Cyr61 with PAD. RESULTS: Out of the 306 subjects enrolled, 150 were free from PAD, while 156 had clinically significant PAD. In subjects with PAD, the prevalences of Fontaine classification stages II, III and IV were 48.7%, 32.1%, and 19.2%, respectively. Patients with more advanced PAD had significantly higher Cyr61 (P for trend < 0.001). The prevalence of PAD on the basis of severity increased with increasing Cyr61 quartiles (all P values for trends < 0.001), and the severity of PAD was positively correlated with Cyr61 quartiles (r = 0.227, P = 0.006). The association of Cyr61 levels with PAD remained after adjusting for major risk factors in a logistic regression analysis. CONCLUSIONS: Our results demonstrated that Cyr61 was significantly increased in PAD patients with T2DM and that Cyr61 levels were positively associated with disease severity. Cyr61 could be a promising biomarker and further studies are needed to assess its clinical utility.

Modulation of SERCA2a expression and function by ultrasound-guided myocardial gene transfection.

Sarco/endoplasmic reticulum Ca²+-ATPase (SERCA2a) is important for cardiac physiological function and pathological progression. However, intravenous injection, a commonly applied approach for gene delivery in most studies investigating the expression of SERCA2a in cardiomyocytes, has not been particularly satisfactory. Therefore, in the present study, a modified method was used to transfect this gene into the heart. Specifically, a SERCA2a-knockdown lentivirus was directly injected into the myocardium of adult rats under ultrasound guidance, following which the effectiveness and feasibility of this proposed approach were evaluated. The results demonstrated that compared with traditional intravenous injection, the modified gene delivery method resulted in markedly higher transfection efficiency. In addition, the SERCA2a-knockdown rats exhibited higher rates of arrhythmia and weaker ventricular wall motions compared with those in the control rats, with these symptoms more evident in the rats that received a direct injection into the myocardium compared with those that were intravenously injected. These results suggest that ultrasound-guided injection into the myocardium is an efficient and safe method for gene delivery and for inducing the knockdown of SERCA2a protein expression in cardiomyocytes in their native environment.