Dapagliflozin protects against chronic heart failure in mice by inhibiting macrophage-mediated inflammation, independent of SGLT2.

The specific mechanism of sodium-glucose cotransporter 2 (SGLT2) inhibitor in heart failure (HF) needs to be elucidated. In this study, we use SGLT2-global-knockout (KO) mice to assess the mechanism of SGLT2 inhibitor on HF. Dapagliflozin ameliorates both myocardial infarction (MI)- and transverse aortic constriction (TAC)-induced HF. Global SGLT2 deficiency does not exert protection against adverse remodeling in both MI- and TAC-induced HF models. Dapagliflozin blurs MI- and TAC-induced HF phenotypes in SGLT2-KO mice. Dapagliflozin causes major changes in cardiac fibrosis and inflammation. Based on single-cell RNA sequencing, dapagliflozin causes significant differences in the gene expression profile of macrophages and fibroblasts. Moreover, dapagliflozin directly inhibits macrophage inflammation, thereby suppressing cardiac fibroblasts activation. The cardio-protection of dapagliflozin is blurred in mice treated with a C-C chemokine receptor type 2 antagonist. Taken together, the protective effects of dapagliflozin against HF are independent of SGLT2, and macrophage inhibition is the main target of dapagliflozin against HF.

PRDM16 exerts critical role in myocardial metabolism and energetics in type 2 diabetes induced cardiomyopathy.

BACKGROUND: The prevalence of type 2 diabetes mellitus (T2DM) has increased over the past decades. Diabetic cardiomyopathy (DCM) is the leading cause of death in T2DM patients, however, the mechanism underlying DCM remains largely unknown. Here, we aimed to investigate the role of cardiac PR-domain containing 16 (PRDM16) in T2DM. METHODS: We modeled mice with cardiac-specific deletion of Prdm16 by crossing the floxed Prdm16 mouse model with the cardiomyocyte-specific Cre transgenic mouse. The mice were continuously fed a chow diet or high-fat diet combining with streptozotocin (STZ) for 24 weeks to establish a T2DM model. DB/DB and adequate control mice were given a single intravenous injection of adeno-associated virus 9 (AAV9) carrying cardiac troponin T (cTnT) promoter-driven small hairpin RNA targeting PRDM16 (AAV9-cTnT-shPRDM16) from the retro-orbital venous plexus to knockout Prdm16 in the myocardium. There were at least 12 mice in each group. Mitochondrial morphology and function were detected using transmission electron microscopy, western blot determining the protein level of mitochondrial respiratory chain complex, mitotracker staining and Seahorse XF Cell Mito Stress Test Kit. Untargeted metabolomics analysis and RNA-seq analysis were performed to determine the molecular and metabolic changes associated with Prdm16 deficiency. BODIPY and TUNEL staining were used to detect lipid uptake and apoptosis. Co-immunoprecipitation and ChIP assays were conducted to examine the potential underlying mechanism. RESULTS: Prdm16 cardiac-specific deficiency accelerated cardiomyopathy and worsened cardiac dysfunction in mice with T2DM, aggravating mitochondrial dysfunction and apoptosis both in vivo and in vitro, while PRDM16 overexpression the deterioration. Prdm16 deficiency also caused cardiac lipid accumulation resulting in metabolic and molecular alterations in T2DM mouse models. Co-IP and luciferase assays confirmed that PRDM16 targeted and regulated the transcriptional activity, expression and interaction of PPAR-α and PGC-1α, while the overexpression of PPAR-α and PGC-1α reversed Prdm16 deficiency-induced cellular dysfunction in T2DM model. Moreover, PRDM16 regulated PPAR-α and PGC-1α and affected mitochondrial function by mainly depending on epigenetic regulation of H3K4me3. CONCLUSIONS: These findings suggest that PRDM16 exerted its protective role in myocardial lipid metabolism and mitochondrial function in T2DM in a histone lysine methyltransferase activity-dependent manner by regulating PPAR-α and PGC-1α.

Cathepsin B deteriorates diabetic cardiomyopathy induced by streptozotocin via promoting NLRP3-mediated pyroptosis.

Cathepsin B (CTSB), a member of lysosomal cathepsin, is involved in cell autophagy and apoptosis. We previously reported that CTSB increased cardiomyocyte apoptosis in mice heart during pressure overload, while the role of CTSB on diabetic cardiomyopathy has not been fully elucidated. The aim of this study is to explore the role and the underlying mechanism of CTSB on diabetic cardiomyopathy. Mice were subjected to streptozotocin injection to induce a diabetes model. Neonatal rat cardiomyocytes were isolated and cultured with high glucose (33.3 mM) to establish an in vitro model. CTSB protein level was increased in diabetic cardiomyopathy (DCM) mice heart as well as in cardiomyocytes stimulated with high glucose. CTSB knockout mice showed ameliorated cardiac function, cardiac fibrosis, cardiac inflammation, and pyroptosis level. Oppositely, DCM mice with CTSB transgene showed exacerbated cardiac dysfunction, fibrosis, inflammation, and pyroptosis. We found that CTSB could bind to NLR family pyrin domain containing 3 (NLRP3), thus increasing the activation of the NLRP3/caspase-1 inflammasome pathway. When we used a NLRP3 knockout mice, the deteriorating effect of CTSB overexpression via adeno-associated virus (AAV)9 delivery was abolished. Taken together, CTSB aggravates diabetic cardiomyopathy via promoting NLRP3-mediated pyroptosis.

Short-chain fatty acid metabolism and multiple effects on cardiovascular diseases.

Cardiovascular diseases (CVDs) are the leading cause of mortality worldwide, and fatty acid metabolism has been well studied. Short-chain fatty acids (SCFAs) have been less discussed than long-chain fatty acids (LCFAs) in CVDs. However, increasing evidence indicates the importance of SCFAs in regulating cardiac function. Here, we summarize the current understanding of SCFAs in hypertension, ischaemic reperfusion, myocardial infarction, atherosclerosis and heart failure. Most SCFAs exert positive effects in regulating related diseases. Butyrate and propionate can reduce blood pressure, improve I/R injury and decrease the risk of coronary artery disease (CAD) and atherosclerosis. Acetate can also play a positive role in regulating hypertension and preventing atherosclerosis, and malonate can improve cardiac function after MI. They affect these diseases by regulating inflammation, the immune system and related G protein-coupled receptors, with multiple neurohumoural regulation participation. In contrast, succinate can accelerate IR injury, increasing mitochondrial ROS production. SCFAs ultimately affect the regulation of different pathophysiological processes in heart failure. Here, we clarified the importance of short-chain fatty acids in the cardiovascular system and their multiple effects in various pathophysiological processes, providing new insights into their promising clinical application. More research should be conducted to further elucidate the underlying mechanism and different effects of single or multiple SCFA supplementation on the cardiovascular system.

Tax1 banding protein 1 exacerbates heart failure in mice by activating ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis.

Tax1 banding protein 1 (Tax1bp1) was originally identified as an NF-κB regulatory protein that participated in inflammatory, antiviral and innate immune processes. Tax1bp1 also functions as an autophagy receptor that plays a role in autophagy. Our previous study shows that Tax1bp1 protects against cardiomyopathy in STZ-induced diabetic mice. In this study we investigated the role of Tax1bp1 in heart failure. Pressure overload-induced heart failure model was established in mice by aortic banding (AB) surgery, and angiotensin II (Ang II)-induced heart failure model was established by infusion of Ang II through osmotic minipump for 4 weeks. We showed that the expression levels of Tax1bp1 in the heart were markedly increased 2 and 4 weeks after AB surgery. Knockdown of Tax1bp1 in mouse hearts significantly ameliorated both AB- and Ang II infusion-induced heart failure parameters. On the contrary, AB-induced heart failure was aggravated in cardiac-specific Tax1bp1 transgenic mice. Similar results were observed in neonatal rat cardiomyocytes (NRCMs) under Ang II insult. We demonstrated that the pro-heart failure effect of Tax1bp1 resulted from its interaction with the E3 ligase ITCH to promote the transcription factor P73 ubiquitination and degradation, causing enhanced BCL2 interacting protein 3 (BNIP3)-mediated cardiomyocyte apoptosis. Knockdown ITCH or BNIP3 in NRCMs significantly reduced Ang II-induced apoptosis in vitro. Similarly, BNIP3 knockdown attenuated heart failure in cardiac-specific Tax1bp1 transgenic mice. In the left ventricles of heart failure patients, Tax1bp1 expression level was significantly increased; Tax1bp1 gene expression was negatively correlated with left ventricular ejection fraction in heart failure patients. Collectively, the Tax1bp1 increase in heart failure enhances ITCH-P73-BNIP3-mediated cardiomyocyte apoptosis and induced cardiac injury. Tax1bp1 may serve as a potent therapeutic target for the treatment of heart failure.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Cardiac Tax1bp1 transgene mice were more vulnerable to cardiac dysfunction under stress.• Knockout of Tax1bp1 in mouse hearts ameliorated heart failure induced by pressure overload.• Tax1bp1 interacts with the E3 ligase Itch to promote P73 ubiquitination and degradation, causing enhanced BNIP3-mediated apoptosis.• Tax1bp1 may become a target of new therapeutic methods for treating heart failure.

Endogenous α7 nAChR Agonist SLURP1 Facilitates Escherichia coli K1 Crossing the Blood-Brain Barrier.

Alpha 7 nicotinic acetylcholine receptor (α7 nAChR) is critical for the pathogenesis of Escherichia coli (E. coli) K1 meningitis, a severe central nervous system infection of the neonates. However, little is known about how E. coli K1 manipulates α7 nAChR signaling. Here, through employing immortalized cell lines, animal models, and human transcriptional analysis, we showed that E. coli K1 infection triggers releasing of secreted Ly6/Plaur domain containing 1 (SLURP1), an endogenous α7 nAChR ligand. Exogenous supplement of SLURP1, combined with SLURP1 knockdown or overexpression cell lines, showed that SLURP1 is required for E. coli K1 invasion and neutrophils migrating across the blood-brain barrier (BBB). Furthermore, we found that SLURP1 is required for E. coli K1-induced α7 nAChR activation. Finally, the promoting effects of SLURP1 on the pathogenesis of E. coli K1 meningitis was significantly abolished in the α7 nAChR knockout mice. These results reveal that E. coli K1 exploits SLURP1 to activate α7 nAChR and facilitate its pathogenesis, and blocking SLURP1-α7 nAChR interaction might represent a novel therapeutic strategy for E. coli K1 meningitis.

High-Mobility Group A1 Promotes Cardiac Fibrosis by Upregulating FOXO1 in Fibroblasts.

High-mobility group A1 (HMGA1) acts as a transcription factor in several cardiovascular diseases. However, the implications of HMGA1 in cardiac fibrosis remain unknown. Here, we investigated the impact of HMGA1 on cardiac fibrosis. A mouse cardiac fibrosis model was constructed via subcutaneous injection of isoproterenol (ISO) or angiotensin II (Ang II) infusion. Adult mouse cardiac fibroblasts (CFs) were isolated and cultured. CFs were stimulated with transforming growth factor-ß1 (TGF-ß1) for 24 h. As a result, HMGA1 was upregulated in fibrotic hearts, as well as TGF-ß-stimulated CFs. Overexpression of HMGA1 in CFs aggravated TGF-ß1-induced cell activation, proliferation, and collagen synthesis. Overexpression of HMGA1 in fibroblasts, by an adeno-associated virus 9 dilution system with a periostin promoter, accelerated cardiac fibrosis and cardiac dysfunction. Moreover, HMGA1 knockdown in CFs inhibited TGF-ß1-induced cell activation, proliferation, and collagen synthesis. Mechanistically, we found that HMGA1 increased the transcription of FOXO1. The FOXO1 inhibitor AS1842856 counteracted the adverse effects of HMGA1 overexpression in vitro. HMGA1 silencing in mouse hearts alleviated Ang II-induced cardiac fibrosis and dysfunction. However, FOXO1 knockdown in mouse hearts abolished the deteriorating effects of HMGA1 overexpression in mice. Collectively, our data demonstrated that HMGA1 plays a critical role in the development of cardiac fibrosis by regulating FOXO1 transcription.

Bacterial O-GlcNAcase genes abundance decreases in ulcerative colitis patients and its administration ameliorates colitis in mice.

OBJECTIVE: O-linked N-acetylglucosaminylation (O-GlcNAcylation), controlled by O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT), is an important post-translational modification of eukaryotic proteins and plays an essential role in regulating gut inflammation. Gut microbiota encode various enzymes involved in O-GlcNAcylation. However, the characteristics, abundance and function of these enzymes are unknown. DESIGN: We first investigated the structure and taxonomic distribution of bacterial OGAs and OGTs. Then, we performed metagenomic analysis to explore the OGA genes abundance in health samples and different diseases. Finally, we employed in vitro and in vivo experiments to determine the effects and mechanisms of bacterial OGAs to hydrolyse O-GlcNAcylated proteins in host cells and suppress inflammatory response in the gut. RESULTS: We found OGAs, instead of OGTs, are enriched in Bacteroidetes and Firmicutes, the major bacterial divisions in the human gut. Most bacterial OGAs are secreted enzymes with the same conserved catalytic domain as human OGAs. A pooled analysis on 1999 metagenomic samples encompassed six diseases revealed that bacterial OGA genes were conserved in healthy human gut with high abundance, and reduced exclusively in ulcerative colitis. In vitro studies showed that bacterial OGAs could hydrolyse O-GlcNAcylated proteins in host cells, including O-GlcNAcylated NF-κB-p65 subunit, which is important for activating NF-κB signalling. In vivo studies demonstrated that gut bacteria-derived OGAs could protect mice from chemically induced colonic inflammation through hydrolysing O-GlcNAcylated proteins. CONCLUSION: Our results reveal a previously unrecognised enzymatic activity by which gut microbiota influence intestinal physiology and highlight bacterial OGAs as a promising therapeutic strategy in colonic inflammation.

The pro-migration and anti-apoptosis effects of HMGA2 in HUVECs stimulated by hypoxia.

High-mobility group AT-hook2 (HMGA2), serving as an architectural transcription factor, participates in plenty of biological processes. Our study is aimed at illustrating the effect of HMGA2 on hypoxia-induced HUVEC injury and the underlying mechanism. To induce hypoxia-related cell injury, HUVECs were exposed to hypoxic condition for 12-24 h. Molecular expression was determined by Western blot analysis, real-time PCR and immunofluorescence staining. Cell migration was monitored by wound healing assay and Transwell chamber assay. Cell proliferation and apoptosis were measured by MTT assay kits and TUNEL staining. In this study, we discovered that HMGA2 was upregulated in hypoxia-induced HUVECs. Overexpression of HMGA2 promoted cell migration, decreased the apoptosis ratio in response to hypoxia stimulation, while HMGA2 knockdown inhibited cell migration and accelerated apoptosis in HUVECs under hypoxic condition. Mechanistically, we found that HMGA2 induced increased expression of HIF-1α,VEGF, eNOS and AKT. eNOS knockdown significantly reduced HMGA2-mediated pro-migration effects, and AKT knockdown strikingly counteracted HMGA2-mediated anti-apoptotic effect. Hence, our data indicated that HMGA2 promoted cell migration by regulating HIF-1α/VGEF/eNOS signaling and prevented cell apoptosis by activating HIF-1α/VGEF/AKT signaling in HUVECs.

S100A8/A9 in Myocardial Infarction: A Promising Biomarker and Therapeutic Target.

Myocardial infarction (MI), the main cause of cardiovascular-related deaths worldwide, has long been a hot topic because of its threat to public health. S100A8/A9 has recently attracted an increasing amount of interest as a crucial alarmin that regulates the pathogenesis of cardiovascular disease after its release from myeloid cells. However, the role of S100A8/A9 in the etiology of MI is not well understood. Here, we elaborate on the critical roles and potential mechanisms of S100A8/A9 driving the pathogenesis of MI. First, cellular source of S100A8/A9 in infarcted heart is discussed. Then we highlight the effect of S100A8/A9 heterodimer in the early inflammatory period and the late reparative period of MI as well as myocardial ischemia/reperfusion (I/R) injury. Moreover, the predictive value of S100A8/A9 for the risk of recurrence of cardiovascular events is elucidated. Therefore, this review focuses on the molecular mechanisms of S100A8/A9 in MI pathogenesis to provide a promising biomarker and therapeutic target for MI.

Cathepsin B aggravated doxorubicin­induced myocardial injury via NF­κB signalling.

Myocyte apoptosis and oxidative stress key critical roles in the process of doxorubicin (DOX)­induced cardiotoxicity. However, how apoptosis and oxidative stress arise in DOX­induced heart injury remains largely unknown. Cathepsin B (CTSB) is a typical lysosomal cysteine protease that is associated with apoptosis, inflammatory responses, oxidative stress and autophagy. The present study aimed to investigate the role of CTSB in DOX­induced heart injury and its potential mechanism. H9C2 cells were infected with adenovirus or transfected with small interfering RNA to overexpress or knock down CTSB, respectively, and then stimulated with DOX. DOX induced increased CTSB expression levels in H9C2 cells. DOX­induced cardiomyocyte apoptosis and oxidative stress were attenuated by CTSB knockdown but aggravated by CTSB overexpression in vitro. Mechanistically, the present study showed that CTSB activated the NF­κB pathway in response to DOX. In summary, CTSB aggravated DOX­induced H9C2 cell apoptosis and oxidative stress via NF­κB signalling. CTSB constitutes a potential therapeutic target for the treatment of DOX­induced cardiotoxicity.

[Establishment of a gp120 transgenic mouse model with α7 nAChR knockout].

OBJECTIVE: To construct a HIV-1 gp120 transgenic mouse model (gp120+) with α7 nicotinic acetylcholine receptor (α7nAChR) gene knockout. METHODS: The α7nAChR gene knockout mice (α7R-/-) were crossed with HIV-1gp120 transgenic mice (gp120+) to generate F1 generation mice. We selected the F1 mice with the genotype of α7R+/-/gp120+ to mate to obtain the F2 mice. The genotypes of the F3 mice were identified by PCR, and the protein expressions in the double transgenic animal model was analyzed by immunohistochemistry. BV2 cells were treated with gp120 protein and α7nAChR inhibitor, and the expressions of IL-1ß and TNF-α were detected using ELISA. RESULTS: The results of PCR showed the bands of the expected size in F3 mice. Two F3 mice with successful double gene editing (α7R-/-/gp120+) were obtained, and immunohistochemistry showed that the brain tissue of the mice did not express α7 nAChR but with high gp120 protein expression. In the in vitro cell experiment, treatment with gp120 promoted the secretion of IL-1ß and TNF-α in BV2 cells, while inhibition of α7nAChR significantly decreased the expression of IL-1ß and TNF-α (P < 0.001). CONCLUSIONS: By mating gp120 Tg mice with α7R-/- mice, we obtained gp120 transgenic mice with α7nAChR gene deletion, which serve as a new animal model for exploring the role of α7nAChR in gp120-induced neurotoxicity.

Nucleotide-Binding Oligomerization Domain-Like Receptor 3 Deficiency Attenuated Isoproterenol-Induced Cardiac Fibrosis via Reactive Oxygen Species/High Mobility Group Box 1 Protein Axis.

Nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) is involved in fibrosis of multiple organs, such as kidney, liver, lung, and the like. However, the role of NLRP3 in cardiac fibrosis is still controversial and remains unclear. The study aims to investigate the role of NLRP3 on cardiac fibrosis induced by isoproterenol (ISO). In vivo, NLRP3 knockout and wild-type mice were subcutaneously injected with ISO to induce the cardiac fibrosis model. The results showed that NLRP3 deficiency alleviated the cardiac fibrosis and inflammation induced by ISO. In vitro, neonatal rat ventricular myocytes (NRVMs) and primary adult mouse cardiac fibroblasts of NLRP3 knockout and wild-type mice were isolated and challenged with ISO. Adenovirus (Ad-) NLRP3 and small interfering RNAs targeting NLRP3 were used to transfect NRVMs to overexpress or knockdown NLRP3. We found that NLRP3 could regulate high-mobility group box 1 protein (HMGB1) secretion via reactive oxygen species production in NRVMs and the HMGB1 secreted by NRVMs promoted the activation and proliferation of cardiac fibroblasts. Thus, we concluded that the NLRP3/reactive oxygen species/HMGB1 pathway could be the underlying mechanism of ISO-induced cardiac fibrosis.

The effect of HMGA1 in LPS-induced Myocardial Inflammation.

Aims: The High Mobility Group A1 (HMGA1) proteins, serving as a dynamic regulator of gene transcription and chromatin remodeling, play an influential part in the pathological process of a large number of cardiovascular diseases. However, the precise role of HMGA1 in sepsis induced cardiomyopathy (SIC) remains unintelligible. This research was designed to illustrate the effect of HMGA1 involved in SIC. Methods and Results: Cardiomyocyte-specific HMGA1 overexpression was obtained using an adeno-associated virus system with intramyocardial injection in mice heart. The model of SIC in mice was constructed via intraperitoneal injection of lipopolysaccharide (LPS) for 6h. H9c2 rat cardiomyocytes was stimulated with LPS for 12h. HMGA1 expression was upregulated in murine inflammatory hearts as well as LPS stimulated H9c2 cardiomyocytes. HMGA1-overexpressing exhibited aggravated cardiac dysfunction, cardiac inflammation as well as cells apoptosis following LPS treatment both in vivo and in vitro experiment. Interestingly, HMGA1 knockdown in H9c2 cardiomyocytes attenuated LPS-induced cardiomyocyte inflammation, but aggravated cell apoptosis. Mechanistically, we found that overexpression of HMGA1 induced increased expression of cyclooxygenase-2 (COX-2). COX-2 inhibitor alleviated the aggravation of inflammation and apoptosis in HMGA1 overexpressed H9c2 cardiomyocytes whereas HMGA1 knockdown induced a reduction in signal transducer and activators of transcription 3 (STAT3) expression. STAT3 agonist reversed HMGA1 silence induced anti-inflammatory effects, while ameliorated cell apoptosis induced by LPS. Conclusion: In conclusion, our results suggest that overexpression of HMGA1 aggravated cardiomyocytes inflammation and apoptosis by up-regulating COX-2 expression, while silence of HMGA1 expression attenuated inflammation but aggregated cell apoptosis via down-regulation of STAT3.

[The postbiotic HM0539 from Lactobacillus rhamnosus GG prevents intestinal infection by enterohemorrhagic E. coli O157: H7 in mice].

OBJECTIVE: To assess the protective effect of the novel postbiotic HM0539 from Lactobacillus rhamnosus GG against intestinal infection by enterohemorrhagic E. coli O157: H7. METHODS: We performed adhesion and invasion experiments to evaluate whether HM0539 could block E. coli O157: H7 adhesion to HT-29 cells. The expressions of mucin2 and the tight junction proteins ZO-1 and Occludin in HM0539-treated HT-29 cells were analyzed using immunofluorescence assay and Western blotting. Animal experiments were conducted in mice to observe the survival rate and changes in body weight, intestinal morphology and the intestinal barrier function after the challenge and HM0539 treatment. RESULTS: HM0539 significantly inhibited the adhesion and invasion of E. coli O157: H7 to HT-29 cells in a dose-dependent manner. HM0539 treatment 4 h prior to E. coli O157: H7 challenge significantly lowered the adhesion and invasion rates of bacteria as compared with the treatment administered at the same time of challenge (P < 0.05). E. coli O157: H7-induced down-regulation of mucin2 and tight junction proteins in HT-29 cells was obviously alleviated by HM0539 treatment of (P < 0.05). In the animal experiment, HM0539 treatment significantly inhibited body weight loss (P < 0.05), alleviated jejunal injury, and inhibited E. coli O157: H7-induced destruction of jejunal goblet cells in the challenged mice (P < 0.05). HM0539 also significantly up-regulated the expression of mucin2 and ZO-1 proteins in the jejunum of E. coli O157:H7-infected mice (P < 0.05). CONCLUSIONS: HM0539 not only inhibits the adhesion and invasion of E. coli O157: H7 to HT-29 cells, but also enhances the resistance against E. coli O157: H7 infection in mice by attenuating the destruction of mucin and tight junction proteins.

High-mobility group AT-hook 1 promotes cardiac dysfunction in diabetic cardiomyopathy via autophagy inhibition.

High-mobility group AT-hook1 (HMGA1, formerly HMG-I/Y), an architectural transcription factor, participates in a number of biological processes. However, its effect on cardiac remodeling (refer to cardiac inflammation, apoptosis and dysfunction) in diabetic cardiomyopathy remains largely indistinct. In this study, we found that HMGA1 was upregulated in diabetic mouse hearts and high-glucose-stimulated cardiomyocytes. Overexpression of HMGA1 accelerated high-glucose-induced cardiomyocyte inflammation and apoptosis, while HMGA1 knockdown relieved inflammation and apoptosis in cardiomyocytes in response to high glucose. Overexpression of HMGA1 in mice heart by adeno-associated virus 9 (AAV9) delivery system deteriorated the inflammatory response, increased apoptosis and accelerated cardiac dysfunction in streptozotocin-induced diabetic mouse model. Knockdown of HMGA1 by AAV9-shHMGA1 in vivo ameliorated cardiac remodeling in diabetic mice. Mechanistically, we found that HMGA1 inhibited the formation rather than the degradation of autophagy by regulating P27/CDK2/mTOR signaling. CDK2 knockdown or P27 overexpression blurred HMGA1 overexpression-induced deteriorating effects in vitro. P27 overexpression in mice heart counteracted HMGA1 overexpression-induced increased cardiac remodeling in diabetic mice. The luciferase reporter experiment confirmed that the regulatory effect of HMGA1 on P27 was mediated by miR-222. In addition, a miR-222 antagomir counteracted HMGA1 overexpression-induced deteriorating effects in vitro. Taken together, our data indicate that HMGA1 aggravates diabetic cardiomyopathy by directly regulating miR-222 promoter activity, which inhibits P27/mTOR-induced autophagy.

Andrographolide Protects Against Adverse Cardiac Remodeling After Myocardial Infarction through Enhancing Nrf2 Signaling Pathway.

Adverse cardiac remodeling after myocardial infarction (MI) is associated with extremely high mortality rates worldwide. Although optimized medical therapy, Preservation of lusitropic and inotropic function and protection against adverse remodeling in ventricular structure remain relatively frequent. This study demonstrated that Andrographolide (Andr) significantly ameliorated adverse cardiac remodeling induced by myocardial infarction and improves contractile function in mice with LAD ligation compared with the control group. Briefly, Andr markedly attenuated cardiac fibrosis and relieved inflammation after myocardial infarction. Specifically, Andr significantly blocked oxidative stress and the nuclear translocation of p-P65 following myocardial infarction. At the mechanistic level, antioxidant effect of Andr was achieved through strengthening antioxidative stress capacity and attributed to the activation of Nrf2/HO-1 Signaling. Consistently, H9C2 administrated with Andr showed a decreased oxidative stress caused by hypoxia precondition, but treatment with specific Nrf2 inhibitor (ML385) or the silence of Nrf2 blunted the activation of Nrf2/HO-1 Signaling and removed the protective effects of Andr in vitro. Thus, we suggest that Andr alleviates adverse cardiac remodeling following myocardial infarction through enhancing Nrf2 signaling pathway.

Clinical characteristics and outcomes in coronavirus disease 2019 (COVID-19) patients with and without hypertension: a retrospective study.

The novel coronavirus disease (COVID-19) has spread all over the world in a short time. Information about the differences between COVID-19 patients with and without hypertension is limited. To explore the characteristics and outcomes differences between COVID-19 patients with and without hypertension, the medical records and cardiac biomarkers of 414 patients were analyzed. A total of 149 patients had a history of hypertension, while 265 patients did not have hypertension, and the groups were compared based on their clinical characteristics and laboratory findings as well as the hazard risk for composite outcomes, including intensive care unit (ICU) admission, mechanical ventilation, or death. The results are as follows. On admission, 22.1% of patients in hypertension group had elevated high sensitivity troponin I (hs-TNI > 26 pg/mL), which was higher than the proportion in the nonhypertension group (6.4%). Median NT-proBNP levels in patients with hypertension (141.9 pg/mL) were higher than those in patients without hypertension (77.3 pg/mL). Patients in the hypertension group had a higher risk for in-hospital death [HR: 2.57, 95% CI (1.46~4.51)]. However, the impact of hypertension on the prognosis was not significant after adjusting for age and sex. Multivariate Cox hazard regression confirmed that NT-proBNP levels in the highest tertile (upper 75 % of patients with hypertension) was an independent risk factor for in-hospital death in all COVID-19 patients. Taken together, hypertension per se had a modest impact on the prognosis in COVID-19 patients. In COVID-19 patients with and without hypertension, NT-proBNP may be a better predictor of prognosis than hs-TNI.

NLRP3-dependent pyroptosis is required for HIV-1 gp120-induced neuropathology.

The human immunodeficiency virus-1 (HIV-1) envelope protein gp120 is the major contributor to the pathogenesis of HIV-associated neurocognitive disorder (HAND). Neuroinflammation plays a pivotal role in gp120-induced neuropathology, but how gp120 triggers neuroinflammatory processes and subsequent neuronal death remains unknown. Here, we provide evidence that NLRP3 is required for gp120-induced neuroinflammation and neuropathy. Our results showed that gp120-induced NLRP3-dependent pyroptosis and IL-1ß production in microglia. Inhibition of microglial NLRP3 inflammasome activation alleviated gp120-mediated neuroinflammatory factor release and neuronal injury. Importantly, we showed that chronic administration of MCC950, a novel selective NLRP3 inhibitor, to gp120 transgenic mice not only attenuated neuroinflammation and neuronal death but also promoted neuronal regeneration and restored the impaired neurocognitive function. In conclusion, our data revealed that the NLRP3 inflammasome is important for gp120-induced neuroinflammation and neuropathology and suggest that NLRP3 is a potential novel target for the treatment of HAND.

Indigo Fruits Ingredient, Aucubin, Protects against LPS-Induced Cardiac Dysfunction in Mice.

Aucubin (AUB), which is extracted from Eucommia ulmoides Oliver seeds, has been found to possess anti-inflammatory and antiapoptotic properties. Recent studies have indicated that inflammation, oxidative stress, and apoptosis are involved in the pathophysiology of lipopolysaccharide (LPS)-induced cardiac dysfunction. Our study aimed to investigate the effect of AUB on LPS-induced acute cardiac injury. Male C57BL/6 mice were injected with LPS (one 6 mg/kg injection) to induce cardiac dysfunction without or with AUB pretreatment (20 or 80 mg/kg per day) for 1 week. We found that AUB ameliorated cardiac dysfunction, inflammation, oxidative stress, and apoptosis induced by LPS stimulation. Mechanistically, AUB inhibited LPS-induced oxidative stress by decreasing reactive oxygen species and thioredoxin interaction protein (TXNIP) levels. Moreover, AUB suppressed LPS-induced inflammation and apoptosis by reducing nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3)/apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC)/caspase-1 inflammasome formation. Overexpression of NLRP3 in cardiomyocytes attenuated the protective effects of AUB. Interestingly, NLRP3 deficiency ameliorated cardiac function and reduced the inflammatory response and oxidative stress after LPS insult in mice, whereas AUB could not further prevent LPS-induced cardiac dysfunction in NLRP3-deficient mice. In summary, AUB exerts a protective effect against LPS-induced inflammation, oxidative stress, and apoptosis in vivo and in vitro by regulating the TXNIP pathway and inactivating the NLRP3/ASC/caspase-1 inflammasome. Hence, AUB may be a promising agent against LPS-induced cardiac dysfunction. SIGNIFICANCE STATEMENT: Aucubin exerts a protective effect against lipopolysaccharide-induced cardiac dysfunction by regulating nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 inflammasome.