Mechanisms and Therapeutic Strategies of Viral Myocarditis Targeting Autophagy

Innovative use of gram-positive enhancer matrix particles and affinity peptides in a vaccine against Coxsackievirus B3

Viral myocarditis (VM) is an inflammatory disease posing a serious threat to public health, with various viral pathogens contributing to its pathogenesis. Coxsackievirus B3 (CVB3) is the most frequently implicated causative agent and has been extensively studied because of its high prevalence and severity. No specific therapeutic interventions for VM exist, and vaccine development has encountered substantial challenges. Therefore, we aimed to develop a novel CVB3 mucosal vaccine as a preventive strategy against VM. Gram-positive enhancer matrice (GEM) particles serve as innovative mucosal vaccine adjuvants and antigen delivery systems that enhance antigen immunogenicity by facilitating effective mucosal immune responses. In this study, GEM particle display technology was used to develop two novel CVB3 vaccines: (1) a GEM particle-based vaccine displaying the CVB3 capsid protein VP1 via a PA anchor protein (GEM-PA-VP1), and (2) a GEM particle-based vaccine displaying VP1 via the FcSP peptide (GEM-Fc-VP1). Both GEM-PA-VP1 and GEM-Fc-VP1 vaacines significantly elevated levels of specific IgG, IgG1, IgG2a, sIgA and neutralizing antibodies in a mouse model, along with enhanced secretion of Th1- and Th2-associated cytokines, compared to controls. Notably, GEM-Fc-VP1 demonstrated superior immunogenicity compared with that of GEM-PA-VP1, evidenced by higher antibody titres and cytokine responses. In challenge protection experiments, both vaccines significantly improved survival rates, reduced myocardial enzyme levels, and decreased inflammatory cell infiltration in myocardial tissue, with GEM-Fc-VP1 exhibiting greater efficacy. These findings establish a foundation for the development of a safe and effective CVB3 candidate vaccine and provide novel insights into the potential of peptide-mediated subunit vaccine approaches.

Role of non-coding RNAs in the pathogenesis of viral myocarditis

Viral myocarditis (VMC) is a common inflammatory disease of the myocardium that is characterized mainly by inflammatory cell infiltration and cardiomyocyte necrosis. Coxsackievirus B3 (CVB3) is a common cause of VMC, although major progress has been made in the treatment of VMC, the long-term prognosis is still not ideal and further research is needed. Non-coding RNAs (ncRNAs) are RNA molecules without coding functions and include microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), which play extensive regulatory roles in gene expression; however, their mechanisms of action in CVB3-induced VMC remain incompletely understood. Here, we review the currently known roles of various ncRNAs in CVB3-induced VMC models, with a focus on cell death, inflammation and viral replication, with the aim of providing a reference for their therapeutic or vaccine development for the treatment of VMC.

Crosstalk Between Innate Immunity and Autophagy in Viral Myocarditis Leading to Dilated Cardiomyopathy

Viral myocarditis, characterised by inflammation of the heart muscle, presents a significant challenge to global public health, particularly affecting younger individuals and often progressing to dilated cardiomyopathy (DCM), a leading cause of heart failure. Despite ongoing research efforts, viable treatments for this condition remain elusive. Recent studies have shed light on the complex interplay between the innate immune response and autophagy mechanisms, revealing their pivotal roles in the pathogenesis of viral myocarditis and subsequent DCM development. This review aims to delve into the recent advancements in understanding the molecular mechanisms and pathways that intersect innate immunity and autophagy in the context of viral myocarditis. Furthermore, it explores the potential therapeutic implications of these findings, offering insights into promising avenues for the management and treatment of this debilitating condition.

Autophagy regulates bone loss via the RANKL/RANK/OPG axis in an experimental rat apical periodontitis model

AIM

Autophagy is involved in human apical periodontitis (AP). However, it is not clear whether autophagy is protective or destructive in bone loss via the receptor activator of nuclear factor-κB ligand (RANKL)/RANK/osteoprotegerin (OPG) axis. This study aimed to investigate the involvement of autophagy via the RANKL/RANK/OPG axis during the development of AP in an experimental rat model.

METHODOLOGY

Twenty-four female Sprague-Dawley rats were divided into control, experimental AP (EAP) + saline, and EAP + 3-methyladenine (An autophagy inhibitor, 3-MA) groups. The control group did not receive any treatment. The EAP + saline group and the EAP + 3-MA group received intraperitoneal injections of saline and 3-MA, respectively, starting 1 week after the pulp was exposed. Specimens were collected for microcomputed tomography (micro-CT) scanning, histological processing, and immunostaining to examine the expression of light chain 3 beta (LC3B), RANK, RANKL, and OPG. Data were analysed using one-way analysis of variance (p < .05).

RESULTS

Micro-CT showed greater bone loss in the EAP + 3-MA group than in the EAP + saline group, indicated by an elevated trabecular space (Tb.Sp) (p < .05). Inflammatory cell infiltration was observed in the EAP + saline and EAP + 3-MA groups. Compared with EAP + saline group, the EAP + 3-MA group showed weaker expression of LC3B (p < .01) and OPG (p < .05), more intense expression of RANK (p < .01) and RANKL (p < .01), and a higher RANKL/OPG ratio (p < .05).

CONCLUSION

Autophagy may exert a protective effect against AP by regulating the RANKL/RANK/OPG axis, thereby inhibiting excessive bone loss.

Acetylation of FOXO1 activates Bim expression involved in CVB3 induced cardiomyocyte apoptosis

Viral myocarditis (VMC) is the major reason for sudden cardiac death among both children and young adults. Of these, coxsackievirus B3 (CVB3) is the most common causative agent of myocarditis. Recently, the role of signaling pathways in the pathogenesis of VMC has been evaluated in several studies, which has provided a new perspective on identifying potential therapeutic targets for this hitherto incurable disease. In the present study, in vivo and in vitro experiments showed that CVB3 infection leads to increased Bim expression and triggers apoptosis. In addition, by knocking down Bim using RNAi, we further confirmed the biological function of Bim in apoptosis induced by CVB3 infection. We additionally found that Bim and forkhead box O1 class (FOXO1) inhibition significantly increased the viability of CVB3-infected cells while blocking viral replication and viral release. Moreover, CVB3-induced Bim expression was directly dependent on FOXO1 acetylation, which is catalyzed by the co-regulation of CBP and SirTs. Furthermore, the acetylation of FOXO1 was an important step in Bim activation and apoptosis induced by CVB3 infection. The findings of this study suggest that CVB3 infection induces apoptosis through the FOXO1 acetylation-Bim pathway, thus providing new insights for developing potential therapeutic targets for enteroviral myocarditis.

Effect of Yangxin Huoxue Jiedu recipe on inflammatory factors and oxidative stress on viral myocarditis in children

OBJECTIVE

This observation purposed to investigate the effect of the Yangxin Huoxue Jiedu formula on children with viral myocarditis and its effect on inflammatory factors and oxidative response.

MATERIALS AND METHODS

A total of 121 children with viral myocarditis were randomly divided into two groups, namely the control group (N = 60) and the traditional Chinese medicine group (N = 61). The control group was mainly treated with routine therapy, while the traditional Chinese medicine group was treated with Yangxin Huoxue Jiedu recipes based on the control group. The creatine kinase, creatine kinase myocardial isoenzyme, aspartate aminotransferase, lactic dehydrogenase, hydroxybutyrate dehydrogenase, cardiac troponin I, brain natriuretic peptide, interleukin-6, interleukin-8, and tumour necrosis factor-alpha, superoxide dismutase and malondialdehyde in viral myocarditis patients were tested to estimate the myocardial function, inflammation, and oxidative situation.

RESULTS

After Yangxin Huoxue Jiedu treatment, 15 cases were recovered, 20 were excellent, and 21 were effective, which had a significant difference from the control group. The concentration of creatine kinase, creatine kinase myocardial isoenzyme, aspartate aminotransferase, lactic dehydrogenase, hydroxybutyrate dehydrogenase, cardiac troponin I and brain natriuretic peptide was decreased in the traditional Chinese medicine group. The levels of interleukin-6, interleukin-8, and tumour necrosis factor-alpha in the traditional Chinese medicine group were significantly lower than those in the control group. Superoxide dismutase was higher and malondialdehyde was lower than those in the control group.

CONCLUSION

The use of Yangxin Huoxue Jiedu in the treatment of viral myocarditis has a definite clinical effect, which could improve myocardial function, reduce body inflammation, and promote oxidative recovery.

Role of Treg cell subsets in cardiovascular disease pathogenesis and potential therapeutic targets

In the genesis and progression of cardiovascular diseases involving both innate and adaptive immune responses, inflammation plays a pivotal and dual role. Studies in experimental animals indicate that certain immune responses are protective, while others exacerbate the disease. T-helper (Th) 1 cell immune responses are recognized as key drivers of inflammatory progression in cardiovascular diseases. Consequently, the CD4+CD25+FOXP3+ regulatory T cells (Tregs) are gaining increasing attention for their roles in inflammation and immune regulation. Given the critical role of Tregs in maintaining immune-inflammatory balance and homeostasis, abnormalities in their generation or function might lead to aberrant immune responses, thereby initiating pathological changes. Numerous preclinical studies and clinical trials have unveiled the central role of Tregs in cardiovascular diseases, such as atherosclerosis. Here, we review the roles and mechanisms of Treg subsets in cardiovascular conditions like atherosclerosis, hypertension, myocardial infarction and remodeling, myocarditis, dilated cardiomyopathy, and heart failure. While the precise molecular mechanisms of Tregs in cardiac protection remain elusive, therapeutic strategies targeting Tregs present a promising new direction for the prevention and treatment of cardiovascular diseases.

Plant-Derived Epi-Nutraceuticals as Potential Broad-Spectrum Anti-Viral Agents

Although the COVID-19 pandemic appears to be diminishing, the emergence of SARS-CoV-2 variants represents a threat to humans due to their inherent transmissibility, immunological evasion, virulence, and invulnerability to existing therapies. The COVID-19 pandemic affected more than 500 million people and caused over 6 million deaths. Vaccines are essential, but in circumstances in which vaccination is not accessible or in individuals with compromised immune systems, drugs can provide additional protection. Targeting host signaling pathways is recommended due to their genomic stability and resistance barriers. Moreover, targeting host factors allows us to develop compounds that are effective against different viral variants as well as against newly emerging virus strains. In recent years, the globe has experienced climate change, which may contribute to the emergence and spread of infectious diseases through a variety of factors. Warmer temperatures and changing precipitation patterns can increase the geographic range of disease-carrying vectors, increasing the risk of diseases spreading to new areas. Climate change may also affect vector behavior, leading to a longer breeding season and more breeding sites for disease vectors. Climate change may also disrupt ecosystems, bringing humans closer to wildlife that transmits zoonotic diseases. All the above factors may accelerate the emergence of new viral epidemics. Plant-derived products, which have been used in traditional medicine for treating pathological conditions, offer structurally novel therapeutic compounds, including those with anti-viral activity. In addition, plant-derived bioactive substances might serve as the ideal basis for developing sustainable/efficient/cost-effective anti-viral alternatives. Interest in herbal antiviral products has increased. More than 50% of approved drugs originate from herbal sources. Plant-derived compounds offer diverse structures and bioactive molecules that are candidates for new drug development. Combining these therapies with conventional drugs could improve patient outcomes. Epigenetics modifications in the genome can affect gene expression without altering DNA sequences. Host cells can use epigenetic gene regulation as a mechanism to silence incoming viral DNA molecules, while viruses recruit cellular epitranscriptomic (covalent modifications of RNAs) modifiers to increase the translational efficiency and transcript stability of viral transcripts to enhance viral gene expression and replication. Moreover, viruses manipulate host cells' epigenetic machinery to ensure productive viral infections. Environmental factors, such as natural products, may influence epigenetic modifications. In this review, we explore the potential of plant-derived substances as epigenetic modifiers for broad-spectrum anti-viral activity, reviewing their modulation processes and anti-viral effects on DNA and RNA viruses, as well as addressing future research objectives in this rapidly emerging field.