Therapeutic strategies targeting mechanisms of macrophages in diabetic heart disease.

Diabetic heart disease (DHD) is a serious complication in patients with diabetes. Despite numerous studies on the pathogenic mechanisms and therapeutic targets of DHD, effective means of prevention and treatment are still lacking. The pathogenic mechanisms of DHD include cardiac inflammation, insulin resistance, myocardial fibrosis, and oxidative stress. Macrophages, the primary cells of the human innate immune system, contribute significantly to these pathological processes, playing an important role in human disease and health. Therefore, drugs targeting macrophages hold great promise for the treatment of DHD. In this review, we examine how macrophages contribute to the development of DHD and which drugs could potentially be used to target macrophages in the treatment of DHD.

Myocardial B cells have specific gene expression and predicted interactions in dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy.

Introduction: Growing evidence from animal models indicates that the myocardium hosts a population of B cells that play a role in the development of cardiomyopathy. However, there is minimal data on human myocardial B cells in the context of cardiomyopathy. Methods: We integrated single-cell and single-nuclei datasets from 45 healthy human hearts, 70 hearts with dilated cardiomyopathy (DCM), and 8 hearts with arrhythmogenic right ventricular cardiomyopathy (ARVC). Interactions between B cells and other cell types were investigated using the CellChat Package. Differential gene expression analysis comparing B cells across conditions was performed using DESeq2. Pathway analysis was performed using Ingenuity, KEGG, and GO pathways analysis. Results: We identified 1,100 B cells, including naive B cells and plasma cells. Cells showed an extensive network of interactions within the healthy myocardium that included outgoing signaling to macrophages, T cells, endothelial cells, and pericytes, and incoming signaling from endothelial cells, pericytes, and fibroblasts. This niche relied on ECM-receptor, contact, and paracrine interactions; and changed significantly in the context of cardiomyopathy, displaying disease-specific features. Differential gene expression analysis showed that in the context of DCM both naive and plasma B cells upregulated several pathways related to immune activation, including upregulation of oxidative phosphorylation, upregulation of leukocyte extravasation, and, in naive B cells, antigen presentation. Discussion: The human myocardium contains naive B cells and plasma cells, integrated into a diverse and dynamic niche that has distinctive features in healthy, DCM, and ARVC. Naive myocardial-associated B cells likely contribute to the pathogenesis of human DCM.

Infliximab Limits Injury in Myocardial Infarction.

BACKGROUND: The purpose of this study was to investigate a therapeutic approach targeting the inflammatory response and consequent remodeling from ischemic myocardial injury. METHODS AND RESULTS: Coronary thrombus aspirates were collected from patients at the time of ST-segment-elevation myocardial infarction and subjected to array-based proteome analysis. Clinically indistinguishable at myocardial infarction (MI), patients were stratified into vulnerable and resilient on the basis of 1-year left ventricular ejection fraction and death. Network analysis from coronary aspirates revealed prioritization of tumor necrosis factor-α signaling in patients with worse clinical outcomes. Infliximab, a tumor necrosis factor-α inhibitor, was infused intravenously at reperfusion in a porcine MI model to assess whether infliximab-mediated immune modulation impacts post-MI injury. At 3 days after MI (n=7), infliximab infusion increased proregenerative M2 macrophages in the myocardial border zone as quantified by immunofluorescence (24.1%±23.3% in infliximab versus 9.29%±8.7% in sham; P<0.01). Concomitantly, immunoassays of coronary sinus samples quantified lower troponin I levels (41.72±7.34 pg/mL versus 58.11±10.75 pg/mL; P<0.05) and secreted protein analysis revealed upregulation of injury-modifying interleukin-2, -4, -10, -12, and -18 cytokines in the infliximab-treated cohort. At 4 weeks (n=12), infliximab treatment resulted in significant protective influence, improving left ventricular ejection fraction (53.9%±5.4% versus 36.2%±5.3%; P<0.001) and reducing scar size (8.31%±10.9% versus 17.41%±12.5%; P<0.05). CONCLUSIONS: Profiling of coronary thrombus aspirates in patients with ST-segment-elevation MI revealed highest association for tumor necrosis factor-α in injury risk. Infliximab-mediated immune modulation offers an actionable pathway to alter MI-induced inflammatory response, preserving contractility and limiting adverse structural remodeling.

Resident and recruited macrophages differentially contribute to cardiac healing after myocardial ischemia.

Cardiac macrophages are heterogenous in phenotype and functions, which has been associated with differences in their ontogeny. Despite extensive research, our understanding of the precise role of different subsets of macrophages in ischemia/reperfusion (I/R) injury remains incomplete. We here investigated macrophage lineages and ablated tissue macrophages in homeostasis and after I/R injury in a CSF1R-dependent manner. Genomic deletion of a fms-intronic regulatory element (FIRE) in the Csf1r locus resulted in specific absence of resident homeostatic and antigen-presenting macrophages, without affecting the recruitment of monocyte-derived macrophages to the infarcted heart. Specific absence of homeostatic, monocyte-independent macrophages altered the immune cell crosstalk in response to injury and induced proinflammatory neutrophil polarization, resulting in impaired cardiac remodeling without influencing infarct size. In contrast, continuous CSF1R inhibition led to depletion of both resident and recruited macrophage populations. This augmented adverse remodeling after I/R and led to an increased infarct size and deterioration of cardiac function. In summary, resident macrophages orchestrate inflammatory responses improving cardiac remodeling, while recruited macrophages determine infarct size after I/R injury. These findings attribute distinct beneficial effects to different macrophage populations in the context of myocardial infarction.

NFĸB signaling drives myocardial injury via CCR2+ macrophages in a preclinical model of arrhythmogenic cardiomyopathy.

Nuclear factor κ-B (NFκB) is activated in iPSC-cardiac myocytes from patients with arrhythmogenic cardiomyopathy (ACM) under basal conditions, and inhibition of NFκB signaling prevents disease in Dsg2mut/mut mice, a robust mouse model of ACM. Here, we used genetic approaches and single-cell RNA-Seq to define the contributions of immune signaling in cardiac myocytes and macrophages in the natural progression of ACM using Dsg2mut/mut mice. We found that NFκB signaling in cardiac myocytes drives myocardial injury, contractile dysfunction, and arrhythmias in Dsg2mut/mut mice. NFκB signaling in cardiac myocytes mobilizes macrophages expressing C-C motif chemokine receptor-2 (CCR2+ cells) to affected areas within the heart, where they mediate myocardial injury and arrhythmias. Contractile dysfunction in Dsg2mut/mut mice is caused both by loss of heart muscle and negative inotropic effects of inflammation in viable muscle. Single nucleus RNA-Seq and cellular indexing of transcriptomes and epitomes (CITE-Seq) studies revealed marked proinflammatory changes in gene expression and the cellular landscape in hearts of Dsg2mut/mut mice involving cardiac myocytes, fibroblasts, and CCR2+ macrophages. Changes in gene expression in cardiac myocytes and fibroblasts in Dsg2mut/mut mice were dependent on CCR2+ macrophage recruitment to the heart. These results highlight complex mechanisms of immune injury and regulatory crosstalk between cardiac myocytes, inflammatory cells, and fibroblasts in the pathogenesis of ACM.

Cardiac resident macrophages: The core of cardiac immune homeostasis.

Cardiac resident macrophages (CRMs) are essential in maintaining the balance of the immune homeostasis in the heart. One of the main factors in the progression of cardiovascular diseases, such as myocarditis, myocardial infarction(MI), and heart failure(HF), is the imbalance in the regulatory mechanisms of CRMs. Recent studies have reported novel heterogeneity and spatiotemporal complexity of CRMs, and their role in maintaining cardiac immune homeostasis and treating cardiovascular diseases. In this review, we focus on the functions of CRMs, including immune surveillance, immune phagocytosis, and immune metabolism, and explore the impact of CRM's homeostasis imbalance on cardiac injury and cardiac repair. We also discuss the therapeutic approaches linked to CRMs. The immunomodulatory strategies targeting CRMs may be a therapeutic approach for the treatment of cardiovascular disease.

Transthyretin-derived amyloid (ATTR) and sarcoidosis: Does ATTR deposition cause a granulomatous inflammatory response in older adults with sarcoidosis?

This study aimed to assess the frequency and association between transthyretin-derived (ATTR) amyloidosis and sarcoidosis in a large autopsy cohort including many cases of sudden cardiac death (SCD). We identified 73 sporadic ATTR amyloidosis cases and 11 sarcoidosis cases, among which we found two cases with concomitant ATTR amyloidosis and sarcoidosis (2.4% of all cases; 2.7% within the sporadic ATTR group). The first case involved a 92-year-old man who experienced SCD. In this patient's heart, we observed ATTR deposition and noncaseating epithelioid granulomas consistent with sarcoidosis. Focally, ATTR deposits and granulomas co-localized, with histiocyte phagocytosis of transthyretin-immunoreactive fragments. However, in most lesions, they were distributed independently. The second case was that of an 86-year-old woman who also experienced SCD. In this patient, we detected ATTR deposition in the heart and lung, while noncaseating epithelioid granulomas were only observed in the lung, liver, kidney, and thyroid. Furthermore, no co-localization of the two lesions was observed. Based on these findings, we concluded that the coexistence of ATTR amyloidosis and sarcoidosis was likely coincidental. Nevertheless, despite the rarity of the combination of these two diseases, it should be recognized as a potential cause of SCD, especially among elderly people.

The Role of the Immune System on the Cardiac Complications Observed in SARS-CoV-2

Abstract An acute respiratory syndrome caused by SARS-CoV2 was declared a pandemic by the World Health Organization. Current data in the world and in Brazil show that approximately 40% of patients who died have some type of cardiac comorbidity. There are also robust reports showing an increase in IL-6 / IL-1B / TNF-alpha and the presence of lymphopenia in patients with COVID-19. Our team and others have shown that increased cytokines are the link between arrhythmias/Left ventricular dysfunction and the immune system in different diseases. In addition, it has been well demonstrated that lymphopenia can not only be a good marker, but also a factor that causes heart failure. Thus, the present review focused on the role of the immune system upon the cardiac alterations observed in the SARS-CoV2 infection. Additionally, it was well described that SARS-CoV-2 is able to infect cardiac cells. Therefore, here it will be reviewed in deep.

Tuning T cell receptor sensitivity through catch bond engineering.

Adoptive cell therapy using engineered T cell receptors (TCRs) is a promising approach for targeting cancer antigens, but tumor-reactive TCRs are often weakly responsive to their target ligands, peptide-major histocompatibility complexes (pMHCs). Affinity-matured TCRs can enhance the efficacy of TCR-T cell therapy but can also cross-react with off-target antigens, resulting in organ immunopathology. We developed an alternative strategy to isolate TCR mutants that exhibited high activation signals coupled with low-affinity pMHC binding through the acquisition of catch bonds. Engineered analogs of a tumor antigen MAGE-A3-specific TCR maintained physiological affinities while exhibiting enhanced target killing potency and undetectable cross-reactivity, compared with a high-affinity clinically tested TCR that exhibited lethal cross-reactivity with a cardiac antigen. Catch bond engineering is a biophysically based strategy to tune high-sensitivity TCRs for T cell therapy with reduced potential for adverse cross-reactivity.

Role of Distinct Macrophage Populations in the Development of Heart Failure in Macrophage Activation Syndrome.

Macrophage activation syndrome (MAS) is one of the few entities in rheumatology with the potential to quickly cause multiple organ failure and loss of life, and as such, requires urgent clinical intervention. It has a broad symptomatology, depending on the organs it affects. One especially dangerous aspect of MAS's course of illness is myocarditis leading to acute heart failure and possibly death. Research in recent years has proved that macrophages settled in different organs are not a homogenous group, with particular populations differing in both structure and function. Within the heart, we can determine two major groups, based on the presence of the C-C 2 chemokine receptor (CCR2): CCR2+ and CCR2-. There are a number of studies describing their function and the changes in the population makeup between normal conditions and different illnesses; however, to our knowledge, there has not been one touching on the matter of changes occurring in the populations of heart macrophages during MAS and their possible consequences. This review summarizes the most recent knowledge on heart macrophages, the influence of select cytokines (those particularly significant in the development of MAS) on their activity, and both the immediate and long-term consequences of changes in the makeup of specific macrophage populations-especially the loss of CCR2- cells that are responsible for regenerative processes, as well as the substitution of tissue macrophages by the highly proinflammatory CCR2+ macrophages originating from circulating monocytes. Understanding the significance of these processes may lead to new discoveries that could improve the therapeutic methods in the treatment of MAS.

Protein Kinase B2 (PKB2/AKT2) Is Essential for Host Protection in CVB3-Induced Acute Viral Myocarditis.

Protein kinase B2 (AKT2) is involved in various cardiomyocyte signaling processes, including those important for survival and metabolism. Coxsackievirus B3 (CVB3) is one of the most common pathogens that cause myocarditis in humans. The role of AKT2 in CVB3 infection is not yet well understood. We used a cardiac-specific AKT2 knockout (KO) mouse to determine the role of AKT2 in CVB3-mediated myocarditis. CVB3 was injected intraperitoneally into wild-type (WT) and KO mice. The mice's survival rate was recorded: survival in KO mice was significantly decreased compared with WT mice (WT vs. KO: 73.3 vs. 27.1%). Myocardial damage and inflammation were significantly increased in the hearts of KO mice compared with those of WT mice. Moreover, from surface ECG, AKT2 KO mice showed a prolonged atria and ventricle conduction time (PR interval, WT vs. KO: 47.27 ± 1.17 vs. 64.79 ± 7.17 ms). AKT2 deletion induced severe myocarditis and cardiac dysfunction due to CVB3 infection. According to real-time PCR, the mRNA level of IL-1, IL-6, and TNF-α decreased significantly in KO mice compared with WT mice on Days 5 after infection. In addition, innate immune response antiviral effectors, Type I interferon (interferon-α and ß), and p62, were dramatically suppressed in the heart of KO mice. In particular, the adult cardiac myocytes isolated from the heart showed high induction of TLR4 protein in KO mice in comparison with WT. AKT2 deletion suppressed the activation of Type I interferon and p62 transcription in CVB3 infection. In cardiac myocytes, AKT2 is a key signaling molecule for the heart from damage through the activation of innate immunity during acute myocarditis.

Impact of cellular myocardial infiltration on clinical outcome in non-ischaemic heart failure.

AIMS: So far, little has been known on whether myocardial inflammatory infiltration influences heart failure (HF) progression. Thus, the aim of this study was to test the impact of intramyocardial infiltration on clinical outcomes. METHODS: Biopsy samples from 358 patients with stable HF secondary to dilated cardiomyopathy were studied. Immunohistochemistry for lymphocyte (CD3) and macrophage (CD68) markers was performed and counted. After a 1-year follow-up, patients were classified as improved based on the predefined definition of improvement. The clinical data were collected from 324 patients (90.5%). RESULTS: According to the predefined definition of improvement, 133 patients improved (41.0%) but 191 remained unchanged or deteriorated (58.9%). After a 12-month follow-up, the OR with 95% CI of counts of myocardial inflammatory CD68-positive ≥4 cell/high power field (HPF) compared with CD68-positive <4 cell/HPF for lack of improvement was 1.91 (1.65-2.54). However, the number of CD3 positive cell infiltration had no impact on clinical outcome after a 1-year follow-up. In the baseline study, a reasonably negative correlation was found between the number of CD68 positive cells and troponin T (r=-0.39; p<0.001 by Spearman's r). This was corroborated with a low negative correlation between these cells and myocardial form of creatine kinase (CK-MB) fraction (r=-0.27; p=0.006). There was no correlation between CD3 and CD68 positive cells (Spearman's r; r=-0.17, p=0.16). CONCLUSIONS: The current results provide evidence that high macrophage counts may be a predisposing factor for HF progression.

Blockade of IL-6/IL-6R Signaling Attenuates Acute Antibody-Mediated Rejection in a Mouse Cardiac Transplantation Model.

Acute antibody-mediated rejection (AAMR) is an important cause of cardiac allograft dysfunction, and more effective strategies need to be explored to improve allograft prognosis. Interleukin (IL)-6/IL-6R signaling plays a key role in the activation of immune cells including B cells, T cells and macrophages, which participate in the progression of AAMR. In this study, we investigated the effect of IL-6/IL-6R signaling blockade on the prevention of AAMR in a mouse model. We established a mouse model of AAMR for cardiac transplantation via presensitization of skin grafts and addition of cyclosporin A, and sequentially analyzed its features. Tocilizumab, anti-IL-6R antibody, and recipient IL-6 knockout were used to block IL-6/IL-6R signaling. We demonstrated that blockade of IL-6/IL-6R signaling significantly attenuated allograft injury and improved survival. Further mechanistic research revealed that signaling blockade decreased B cells in circulation, spleens, and allografts, thus inhibiting donor-specific antibody production and complement activation. Moreover, macrophage, T cell, and pro-inflammatory cytokine infiltration in allografts was also reduced. Collectively, we provided a highly practical mouse model of AAMR and demonstrated that blockade of IL-6/IL-6R signaling markedly alleviated AAMR, which is expected to provide a superior option for the treatment of AAMR in clinic.

Dynamics of Polarized Macrophages and Activated CD8+ Cells in Heart Tissue of Atlantic Salmon Infected With Piscine Orthoreovirus-1.

Piscine orthoreovirus (PRV-1) infection causes heart and skeletal muscle inflammation (HSMI) in farmed Atlantic salmon (Salmo salar). The virus is also associated with focal melanized changes in white skeletal muscle where PRV-1 infection of macrophages appears to be important. In this study, we studied the macrophage polarization into M1 (pro-inflammatory) and M2 (anti-inflammatory) phenotypes during experimentally induced HSMI. The immune response in heart with HSMI lesions was characterized by CD8+ and MHC-I expressing cells and not by polarized macrophages. Fluorescent in situ hybridization (FISH) assays revealed localization of PRV-1 in a few M1 macrophages in both heart and skeletal muscle. M2 type macrophages were widely scattered in the heart and were more abundant in heart compared to the skeletal muscle. However, the M2 macrophages did not co-stain for PRV-1. There was a strong cellular immune response to the infection in the heart compared to that of the skeletal muscle, seen as increased MHC-I expression, partly in cells also containing PRV-1 RNA, and a high number of cytotoxic CD8+ granzyme producing cells that targeted PRV-1. In skeletal muscle, MHC-I expressing cells and CD8+ cells were dispersed between myocytes, but these cells did not stain for PRV-1. Gene expression analysis by RT-qPCR complied with the FISH results and confirmed a drop in level of PRV-1 following the cell mediated immune response. Overall, the results indicated that M1 macrophages do not contribute to the initial development of HSMI. However, large numbers of M2 macrophages reside in the heart and may contribute to the subsequent fast recovery following clearance of PRV-1 infection.

Chronic Porphyromonas gingivalis lipopolysaccharide induces adverse myocardial infarction wound healing through activation of CD8+ T cells.

Oral and gum health have long been associated with incidence and outcomes of cardiovascular disease. Periodontal disease increases myocardial infarction (MI) mortality by sevenfold through mechanisms that are not fully understood. The goal of this study was to evaluate whether lipopolysaccharide (LPS) from a periodontal pathogen accelerates inflammation after MI through memory T-cell activation. We compared four groups [no MI, chronic LPS, day 1 after MI, and day 1 after MI with chronic LPS (LPS + MI); n = 68 mice] using the mouse heart attack research tool 1.0 database and tissue bank coupled with new analyses and experiments. LPS + MI increased total CD8+ T cells in the left ventricle versus the other groups (P < 0.05 vs. all). Memory CD8+ T cells (CD44 + CD27+) were 10-fold greater in LPS + MI than in MI alone (P = 0.02). Interleukin (IL)-4 stimulated splenic CD8+ T cells away from an effector phenotype and toward a memory phenotype, inducing secretion of factors associated with the Wnt/ß-catenin signaling that promoted monocyte migration and decreased viability. To dissect the effect of CD8+ T cells after MI, we administered a major histocompatibility complex-I-blocking antibody starting 7 days before MI, which prevented effector CD8+ T-cell activation without affecting the memory response. The reduction in effector cells diminished infarct wall thinning but had no effect on macrophage numbers or MertK expression. LPS + MI + IgG attenuated macrophages within the infarct without effecting CD8+ T cells, suggesting these two processes were independent. Overall, our data indicate that effector and memory CD8+ T cells at post-MI day 1 are amplified by chronic LPS to potentially promote infarct wall thinning.NEW & NOTEWORTHY Although there is a well-documented link between periodontal disease and heart health, the mechanisms are unclear. Our study indicates that in response to circulating periodontal endotoxins, memory CD8+ T cells are activated, resulting in an acceleration of macrophage-mediated inflammation after MI. Blocking activation of effector CD8+ T cells had no effect on the macrophage numbers or wall thinning at post-MI day 1, indicating that this response was likely due in part to memory CD8+ T cells.

Down-regulation of VCAM-1 in bone mesenchymal stem cells reduces inflammatory responses and apoptosis to improve cardiac function in rat with myocardial infarction.

BACKGROUND: Bone mesenchymal stem cells (BMSCs) has been well known to exert therapeutic potential for patients with myocardial infarction (MI). VCAM-1 can promote the migration of lymphocytes to the inflammatory zone. In the present study, we tried to explore whether VCAM-1 silenced-BMSCs have better therapeutic effects on MI. METHODS: BMSCs were isolated and cultured followed by treatment of a lentivirus silencing VCAM-1 and NF-κB activator (PMA). Besides, MI rat models were also established and injected with treated BMSCs to detect the effect of VCAM-1 silenced-BMSCs in MI, as evidenced by detection of cardiac function, survival of rats within 72 h, infarct size and myocardial cell apoptosis. Moreover, the expression of NF-κB-regulated gene products was also determined. RESULTS: The implantation of sh-VCAM-1 BMSCs into MI rats resulted in more reductions in myocardial infarct size as well as myocardial cell apoptosis, improved cardiac function, the number of survived rats within 72 h, and survival time within 72 h compared with the individual treatments of either BMSCs or control. In addition, transplanted BMSCs down-regulated the expression of NF-κB-p65, MMP-9, TNF-α, and Bax, and up-regulated VEGF and Bcl-2 in myocardial tissue, which could be further enhanced by sh-VCAM-1 and rescued by PMA. CONCLUSION: Our study demonstrated that silencing VCAM-1 in BMSCs could inhibit inflammation and apoptosis, thus improving cardiac function in MI.

Pathological review of cardiac amyloidosis using autopsy cases in a single Japanese institution.

AIM: Amyloidosis is a systemic or localized disease of protein deposition characterized by amorphous eosinophilic morphology and positivity of Congo Red staining. The typing of amyloidosis is becoming increasingly important because therapeutic agents for each amyloidosis type have been developed. Herein, the authors review the autopsy cases at an institution to reveal the putative Japanese characteristics of each amyloidosis type and evaluate the clinicopathological significance of each type. MATERIALS AND METHODS: A total of 131 autopsy cases of systemic and localized amyloidosis were retrieved for classification by immunohistochemistry. Immunohistochemistry for transthyretin, amyloid A (AA), immunoglobulin light-chain kappa and lambda, and ß2-microglobulin was performed for all cases. RESULTS: The 131 amyloidosis cases were classified as follows: 71 cases (54.2%) of transthyretin amyloidosis, 32 cases (24.4%) of AA amyloidosis, 8 cases (6.1%) of light-chain amyloidosis, and 5 cases (3.8%) of ß2-microglobulin amyloidosis, along with 15 equivocal cases (11.5%). All cases showed myocardial involvement of amyloidosis. Histopathologically, the transthyretin type was significantly associated with the interstitial and nodular patterns, and with the absence of the perivascular and endocardial patterns. The AA type was significantly associated with the perivascular and endocardial patterns, and with the absence of the nodular pattern. CONCLUSION: The authors revealed the putative characteristics of cardiac amyloidosis in Japan by using autopsy cases. About 90% of amyloidosis cases were successfully classified using only commercially available antibodies.

NORAD lentivirus shRNA mitigates fibrosis and inflammatory responses in diabetic cardiomyopathy via the ceRNA network of NORAD/miR-125a-3p/Fyn.

OBJECTIVE: Diabetic cardiomyopathy (DCM) is a serious complication of diabetes, but its pathogenesis is still unclear. This study investigated the mechanism of long noncoding RNA (lncRNA) NORAD in DCM. METHODS: Male leptin receptor-deficient (db/db) mice and leptin control mice (db/ +) were procured. DCM model was established by subcutaneous injection of angiotensin II (ATII) in db/db mice. NORAD lentivirus shRNA or Adv-miR-125a-3p was administered to analyze cardiac function, fibrosis, serum biochemical indexes, inflammation and fibrosis. Primary cardiomyocytes were extracted and transfected with miR-125a-3p mimic. The competing endogenous RNA (ceRNA) network of NORAD/miR-125a-3p/Fyn was verified. The levels of fibrosis- and inflammation-related factors were measured. RESULTS: In db/db mice treated with ATII, the body weight and serum biochemical indexes were increased, while the cardiac function was decreased, and inflammatory cell infiltration and fibrosis were induced. NORAD was upregulated in diabetic and DCM mice. The 4-week intravenous injection of NORAD lentivirus shRNA reduced body weight and serum biochemical indexes, improved cardiac function, and attenuated inflammation and fibrosis in DCM mice. NORAD acted as a sponge to adsorb miR-125a-3p, and miR-125a-3p targeted Fyn. Intravenous injection of miR-125a-3p adenovirus improved cardiac function and fibrosis and reduced inflammatory responses in DCM mice. Co-overexpression of miR-125-3p and Fyn partly reversed the improving effect of miR-125-3p overexpression on cardiac fibrosis in DCM mice. CONCLUSION: NORAD lentivirus shRNA improved cardiac function and fibrosis and reduced inflammatory responses in DCM mice via the ceRNA network of NORAD/miR-125a-3p/Fyn. These findings provide a valuable and promising therapeutic target for the treatment of DCM.

Tumor Necrosis Factor-Alpha Exacerbates Viral Entry in SARS-CoV2-Infected iPSC-Derived Cardiomyocytes.

The coronavirus disease 2019 (COVID-19) pandemic with high infectivity and mortality has caused severe social and economic impacts worldwide. Growing reports of COVID-19 patients with multi-organ damage indicated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) may also disturb the cardiovascular system. Herein, we used human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (iCMs) as the in vitro platform to examine the consequence of SARS-CoV2 infection on iCMs. Differentiated iCMs expressed the primary SARS-CoV2 receptor angiotensin-converting enzyme-II (ACE2) and the transmembrane protease serine type 2 (TMPRSS2) receptor suggesting the susceptibility of iCMs to SARS-CoV2. Following the infection of iCMs with SARS-CoV2, the viral nucleocapsid (N) protein was detected in the host cells, demonstrating the successful infection. Bioinformatics analysis revealed that the SARS-CoV2 infection upregulates several inflammation-related genes, including the proinflammatory cytokine tumor necrosis factor-α (TNF-α). The pretreatment of iCMs with TNF-α for 24 h, significantly increased the expression of ACE2 and TMPRSS2, SASR-CoV2 entry receptors. The TNF-α pretreatment enhanced the entry of GFP-expressing SARS-CoV2 pseudovirus into iCMs, and the neutralization of TNF-α ameliorated the TNF-α-enhanced viral entry. Collectively, SARS-CoV2 elevated TNF-α expression, which in turn enhanced the SARS-CoV2 viral entry. Our findings suggest that, TNF-α may participate in the cytokine storm and aggravate the myocardial damage in COVID-19 patients.

Depletion of ß3-adrenergic receptor relieves pressure overload-induced cardiac hypertrophy and heart failure via enhancing innate immune response.

Cardiac pressure overload is a crucial risk factor for cardiac hypertrophy and heart failure. Our previous study showed that depletion of the ß3-adrenergic receptor (ADRB3) induced left ventricular diastolic dysfunction via potential regulation of energy metabolism and cardiac contraction. However, the effects of ADRB3 on pressure overload-induced heart failure remain unclear. In the present study, systemic ADRB3-knockout mice suffering from transverse aortic constriction (TAC) surgery were used to identify the effects of ADRB3 on pressure overload-induced heart failure. Compared to wild-type mice, ADRB3 depletion significantly improved the left ventricular ejection fraction, reduced left ventricular posterior wall thickness and interventricular septum thickness, and decreased the area of cardiomyocytes after TAC. RNA sequencing and bioinformatics analysis showed that ADRB3 depletion up-regulated 275 mRNAs and down-regulated 105 mRNAs in mice suffering TAC surgery. GO analysis, GO-tree analysis, and GSEA showed that ADRB3 depletion mainly enhanced the innate immune response of hearts in cardiac pressure overload mice. In addition, pathway analysis and Pathway-Act analysis presented that innate immune response-related pathways, including RIG-I-like receptor signaling pathway, antigen processing and presentation, Toll-like receptor signaling pathway, and cell adhesion molecules, were significantly enriched in ADRB3-KO-TAC mice. Ten hub genes were identified using protein-protein interaction network, MCODE, and cytoHubba analysis. Furthermore, the depletion and activation of ADRB3 validated the effects of ADRB3 on the innate immune response of hearts after TAC. In conclusion, ADRB3 depletion relieves pressure overload-induced cardiac hypertrophy and heart failure, and these effects could be explained by the enhancement of innate immune response.