Potential involvement of S1PR1/STAT3 signaling pathway in cardiac valve damage due to rheumatic heart disease

Exosomal non-coding RNAs: key regulators of inflammation-related cardiovascular disorders

Inflammation is a complex, tightly regulated process involving biochemical and cellular reactions to harmful stimuli. Often termed "the internal fire", it is crucial for protecting the body and facilitating tissue healing. While inflammation is essential for survival, chronic inflammation can be detrimental, leading to tissue damage and reduced survival. The innate immune system triggers inflammation, closely linked to the development of heart diseases, with significant consequences for individuals. Inflammation in arterial walls or the body substantially contributes to atherosclerotic disease progression, affecting the cardiovascular system. Altered lipoproteins increase the risk of excessive blood clotting, a hallmark of atherosclerotic cardiovascular disease and its complications. Integrating inflammatory biomarkers with established risk assessment techniques can enhance our ability to identify at-risk individuals, assess their risk severity, and recommend appropriate CVD prevention strategies. Exosomes, a type of extracellular vesicle, are released by various cells and mediate cell communication locally and systemically. In the past decade, exosomes have been increasingly studied for their vital roles in health maintenance and disease processes. They can transport substances like non-coding RNAs, lipids, and proteins between cells, influencing immune responses and inflammation to elicit harmful or healing effects. This study focuses on the critical role of inflammation in heart disease progression and how non-coding RNAs in exosomes modulate the inflammatory process, either exacerbating or alleviating inflammation-related damage in the cardiovascular system.

Inhibition of Endothelial-Mesenchymal Transition Mediated by Activin Receptor Type IIA Attenuates Valvular Injury Induced by Group A Streptococcus in Lewis Rats

BACKGROUND

Rheumatic heart disease (RHD), which is caused mainly by Group A Streptococcus, leads to fibrotic damage to heart valves. Recently, endothelial‒mesenchymal transition (EndMT), in which activin plays an important role, has been shown to be an important factor in RHD valvular injury. However, the mechanism of activin activity and EndMT in RHD valvular injury is not clear.

METHODS

Our study was divided into two parts: in vivo and in vitro. We constructed a small interfering RNA (ACVR2A-siRNA) by silencing activin receptor type IIA (ACVR2A) and an adeno-associated virus (AAV-ACVR2A) containing a sequence that silenced ACVR2A. The EndMT cell model was established via human umbilical vein endothelial cells (HUVECs), and the RHD animal model was established via female Lewis rats. ACVR2A-siRNA and AAV-ACVR2A were used in the above experiments.

RESULTS

EndMT occurred in the valvular tissues of RHD rats, and activin and its associated intranuclear transcription factors were also activated during this process, with inflammatory infiltration and fibrotic damage also occurring in the valvular tissues. After inhibition of ACVR2A, EndMT in valvular tissues was also inhibited, and inflammatory infiltration and fibrosis were reduced. Endothelial cell experiments suggested that mesenchymal transition could be stimulated by activin and that inhibition of ACVR2A attenuated mesenchymal transition.

CONCLUSIONS

Activin plays an important role in signal transduction during EndMT after activation, and inhibition of ACVR2A may attenuate RHD valvular damage by mediating EndMT. Targeting ACVR2A may be a therapeutic strategy to alleviate RHD valvular injury.

LINC00707 inhibits myocardial fibrosis and immune disorder in rheumatic heart disease by regulating miR-145-5p/S1PR1

LINC00707 is a lncRNA that can regulate a variety of diseases. This study mainly investigated that the expression of LINC00707 in rheumatic heart disease (RHD) and LINC00707 regulates S1PR1 by targeting miR-145-5p to inhibit myocardial fibrosis and immune disorder in RHD. A rat model of RHD induced by inactivated group A β-hemolytic streptococcus (GSA) was established. Sixty female Lewis rats (8 weeks of age) were randomly divided into six groups, including control (Con), RHD, RHD+NC, RHD+LINC00707, RHD+miR-145-5p and RHD+LINC00707+miR-145-5p. The mRNA expression was detected by Quantitative Real-time polymerase chain reaction (qRT-PCR). Protein expression of S1PR1 was detected by western blot. The levels of myocardial damage markers (CK-MB, cTnl) and inflammatory immune markers (IL-6, IL-17 and IL-21) were measured by enzyme linked immunosorbent assay (ELISA). The Collagen III/I(COLIII/I) ratio, mRNA expression of COLIIIα1 and FSP1 of rat heart valve tissue in the RHD group was observably higher by comparison with the CON group. The expression of LINC00707 was observably lower in the RHD group. LINC00707 inhibited myocardial fibrosis and immune disorder in RHD. MiR-145-5p was the target gene of LINC00707 via Targetscan prediction. Luciferase reporter experiment confirmed that miR-145-5p was directly regulated by LINC00707. The expression of miR-145-5p in the RHD group was observably higher by comparison with the CON group and LINC00707 observably decreased the expression of miR-145-5p. miR-145-5p mimic reversed the inhibiting effect of LINC00707 on myocardial fibrosis and immune disorder. Furthermore, S1PR1 was confirmed to be downstream gene of miR-145-5p and low expressed in the RHD model. LINC00707 could inhibit myocardial fibrosis and immune disorder in RHD by regulating miR-145-5p/S1PR1.

Methods for Establishing a Rat Model of Rheumatic Heart Disease

Rheumatic heart disease (RHD) is responsible for nearly 250,000 deaths annually and poses a significant health threat in developing areas. The unclear pathogenesis of RHD makes the development of cost-effective treatments challenging, particularly as current surgical options are expensive and technologically demanding, exacerbating the economic and quality-of-life burdens for patients. Given the risks associated with direct human experimentation due to the uncertain pathogenesis, using a rat model infected with Group A Streptococcus (GAS) has become a crucial experimental strategy for RHD research. The development of an RHD rat model, refined over 23 years, now stands as a pivotal approach in studies aiming to understand the disease's pathogenesis. This review summarizes the evolution, characteristics, advantages, and limitations of the RHD rat model, offering insights into potential areas for improvement. It aims to provide researchers with a comprehensive understanding of the model, supporting the advancement of research methodologies and the discovery of innovative treatments for RHD.

Unraveling the Mechanisms of Valvular Heart Disease to Identify Medical Therapy Targets: A Scientific Statement From the American Heart Association

Valvular heart disease is a common cause of morbidity and mortality worldwide and has no effective medical therapy. Severe disease is managed with valve replacement procedures, which entail high health care-related costs and postprocedural morbidity and mortality. Robust ongoing research programs have elucidated many important molecular pathways contributing to primary valvular heart disease. However, there remain several key challenges inherent in translating research on valvular heart disease to viable molecular targets that can progress through the clinical trials pathway and effectively prevent or modify the course of these common conditions. In this scientific statement, we review the basic cellular structures of the human heart valves and discuss how these structures change in primary valvular heart disease. We focus on the most common primary valvular heart diseases, including calcific aortic stenosis, bicuspid aortic valves, mitral valve prolapse, and rheumatic heart disease, and outline the fundamental molecular discoveries contributing to each. We further outline potential therapeutic molecular targets for primary valvular heart disease and discuss key knowledge gaps that might serve as future research priorities.

Precision Medicine in Congenital Heart Disease, Rheumatic Heart Disease, and Kawasaki Disease of Children: An Overview of Literature

Congenital heart disease and common acquired heart diseases like Kawasaki disease and rheumatic heart disease are prevalent cardiovascular conditions in children worldwide. Despite the availability of treatment options, they continue to be significant contributors to morbidity and mortality. Advancements in early diagnosis, improvements in treatment approaches, and overcoming resistance to available treatments are crucial to reduce morbidity. Researchers have turned to precision medicine to tackle these challenges. We aimed to analyze the existing literature concerning the utilization of precision medicine in congenital heart disease, rheumatic heart disease, and Kawasaki disease. The emphasis is placed on comprehending the key themes explored in these studies and evaluating the present state of their clinical integration. The central theme of most studies revolves around the examination of genetic factors. Despite promising research outcomes, limitations in these studies indicate that the clinical implementation of precision medicine in these conditions remains a distant prospect, necessitating additional exploration and attention to confounding factors.

MicroRNA-155 and exosomal microRNA-155: Small pieces in the cardiovascular diseases puzzle

MicroRNAs (miRs, miRNAs) are known to have a part in various human illnesses, such as those related to the heart. One particular miRNA, miR-155, has been extensively studied and has been found to be involved in hematopoietic lineage differentiation, immunity, viral infections, inflammation, as well as vascular remodeling. These processes have all been connected to cardiovascular diseases, including heart failure, diabetic heart disease, coronary artery disease, and abdominal aortic aneurysm. The impacts of miR-155 depend on the type of cell it is acting on and the specific target genes involved, resulting in different mechanisms of disease. Although, the exact part of miR-155 in cardiovascular illnesses is yet not fully comprehended, as some studies have shown it to promote the development of atherosclerosis while others have shown it to prevent it. As a result, to comprehend the underlying processes of miR-155 in cardiovascular disorders, further thorough study is required. It has been discovered that exosomes that could be absorbed by adjacent or distant cells, control post-transcriptional regulation of gene expression by focusing on mRNA. Exosomal miRNAs have been found to have a range of functions, including participating in inflammatory reactions, cell movement, growth, death, autophagy, as well as epithelial-mesenchymal transition. An increasing amount of research indicates that exosomal miRNAs are important for cardiovascular health and have a major role in the development of a number of cardiovascular disorders, including pulmonary hypertension, atherosclerosis, acute coronary syndrome, heart failure, and myocardial ischemia-reperfusion injury. Herein the role of miR-155 and its exosomal form in heart diseases are summarized.

Interference with the expression of S1PR1 or STAT3 attenuates valvular damage due to rheumatic heart disease

Rheumatic heart disease (RHD) affects numerous individuals annually; however, its pathogenesis remains unclear. The sphingosine 1‑phosphate receptor 1 (S1PR1) and signal transducer and activator of transcription 3 (STAT3) have recently been shown to be involved in valvular damage via the promotion of the differentiation of T helper 17 (Th17) cells during the development of RHD‑induced valvular damage. The present study investigated whether altering the expression of S1PR1 or STAT3 attenuates valvular damage due to RHD. Inactivated group A streptococcus (GAS) was used to establish a rat model of RHD. Recombinant adeno‑associated viral vectors carrying an S1PR1 overexpression sequence were used to overexpress S1PR1. STAT3 small interfering RNA (STAT3‑siRNA) was used to inhibit STAT3 expression. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to detect the mRNA expression of S1PR1, STAT3, collagen type III α1 chain (Col3a1) and fibroblast‑specific protein 1. Western blotting (WB) and immunohistochemistry were used to detect the levels of S1PR1, STAT3, phosphorylated (p‑) STAT3, and retinoic acid‑related orphan receptor γT (RORγt) proteins. Enzyme‑linked immunosorbent assays (ELISAs) and immunohistochemistry were used to detect the levels of interleukin (IL)‑6 and IL‑17. Hematoxylin and eosin (H&E) staining and Sirius Red staining were performed to evaluate the degree of inflammation and fibrosis in the valvular tissues. S1PR1 expression was decreased in the valvular tissues of the rats with RHD. The levels of IL‑6, IL‑17 and p‑STAT3 in the rats with RHD were increased. The degree of valvular inflammation and fibrosis in the rats with RHD was also increased. The overexpression of S1PR1 and the inhibition of STAT3 reduced the total p‑STAT3 level, resulting in decreased levels of IL‑6, IL‑17 and RORγt, and a reduced degree of valvular inflammation and fibrosis. These results suggest that the expression of S1PR1 and STAT3 may be involved in valvular tissue damage due to RHD. Thus, strategies designed to interfere with the expression of S1PR1 or STAT3 may affect the expression of Th17 cell‑related cytokines and may thus attenuate valvular damage due to RHD.

Echocardiography for latent rheumatic heart disease in first degree relatives of children with acute rheumatic fever: Implications for active case finding in family members

BACKGROUND

Individuals with Acute Rheumatic Fever (ARF) often report a family history of ARF or Rheumatic Heart Disease (RHD) however the degree of familial susceptibility to RHD is poorly defined. This study aimed to determine RHD prevalence among first degree relatives of ARF patients using echocardiography.

METHODS

Children with ARF were recruited from Auckland, New Zealand. Parents and siblings ≥ 4years were offered echocardiography. Echocardiograms were reported according to World Heart Federation 2012 criteria. RHD prevalence in first degree relatives was compared to previously established population rates in the region.

FINDINGS

In total, 70 index cases with ARF were recruited. Echocardiography was performed in 94 parents and 132 siblings. There were 3 siblings with definite RHD and 9 with borderline RHD. There were 4 parents with definite RHD. Overall prevalence of RHD (definite and borderline) in siblings was 90/1,000 (95% CI 45-143/1,000) compared to 36/1,000 (95% CI 30-42/1,000) in New Zealand children from high ARF incidence populations (p 0.001). Prevalence of definite RHD in parents was 42/1,000 (95% CI 7-87/1,000) compared to 22/1,000 (95% CI 9-36/1,000) in adults from a high ARF incidence New Zealand population (p 0.249).

INTERPRETATION

RHD prevalence in siblings and parents of ARF cases is significantly greater than in comparable background populations. The contribution of hereditary versus environmental risk factors remains uncertain. We recommend targeted echocardiographic case-finding among siblings and parents of ARF/RHD cases in order to detect previously unrecognized latent RHD.

In Search of the Holy Grail: A Specific Diagnostic Test for Rheumatic Fever

Current diagnosis of Acute Rheumatic Fever and Rheumatic Heart Disease (ARF/RHD) relies on a battery of clinical observations aided by technologically advanced diagnostic tools and non-specific laboratory tests. The laboratory-based assays fall into two categories: those that (1) detect "evidence of preceding streptococcal infections" (ASOT, anti-DNAse B, isolation of the Group A Streptococcus from a throat swab) and (2) those that detect an ongoing inflammatory process (ESR and CRP). These laboratory tests are positive during any streptococcal infection and are non-specific for the diagnosis of ARF/RHD. Over the last few decades, we have accumulated considerable knowledge about streptococcal biology and the immunopathological mechanisms that contribute to the development, progression and exacerbation of ARF/RHD. Although our knowledge is incomplete and many more years will be devoted to understanding the exact molecular and cellular mechanisms involved in the spectrum of clinical manifestations of ARF/RHD, in this commentary we contend that there is sufficient understanding of the disease process that using currently available technologies it is possible to identify pathogen associated peptides and develop a specific test for ARF/RHD. It is our view that with collaboration and sharing of well-characterised serial blood samples from patients with ARF/RHD from different regions, antibody array technology and/or T-cell tetramers could be used to identify streptococcal peptides specific to ARF/RHD. The availability of an appropriate animal model for this uniquely human disease can further facilitate the determination as to whether these peptides are pathognomonic. Identification of such peptides will also facilitate testing of potential anti-streptococcal vaccines for safety and avoid potential candidates that may pre-dispose potential vaccine recipients to adverse outcomes. Such peptides can also be readily incorporated into a universally affordable point of care device for both primary and tertiary care.

Requirements for a Robust Animal Model to Investigate the Disease Mechanism of Autoimmune Complications Associated With ARF/RHD

The pathogenesis of Acute Rheumatic Fever/Rheumatic Heart Disease (ARF/RHD) and associated neurobehavioral complications including Sydenham's chorea (SC) is complex. Disease complications triggered by Group A streptococcal (GAS) infection are confined to human and determining the early events leading to pathology requires a robust animal model that reflects the hallmark features of the disease. However, modeling these conditions in a laboratory animal, of a uniquely human disease is challenging. Animal models including cattle, sheep, pig, dog, cat, guinea pigs rats and mice have been used extensively to dissect molecular mechanisms of the autoimmune inflammatory responses in ARF/RHD. Despite the characteristic limitations of some animal models, several rodent models have significantly contributed to better understanding of the fundamental mechanisms underpinning features of ARF/RHD. In the Lewis rat autoimmune valvulitis model the development of myocarditis and valvulitis with the infiltration of mononuclear cells along with generation of antibodies that cross-react with cardiac tissue proteins following exposure to GAS antigens were found to be similar to ARF/RHD. We have recently shown that Lewis rats injected with recombinant GAS antigens simultaneously developed cardiac and neurobehavioral changes. Since ARF/RHD is multifactorial in origin, an animal model which exhibit the characteristics of several of the cardinal diagnostic criteria observed in ARF/RHD, would be advantageous to determine the early immune responses to facilitate biomarker discovery as well as provide a suitable model to evaluate treatment options, safety and efficacy of vaccine candidates. This review focuses on some of the common small animals and their advantages and limitations.

The Role of Exosomes and Exosomal MicroRNA in Cardiovascular Disease

Exosomes are small vesicles (30–150 nm in diameter) enclosed by a lipid membrane bilayer, secreted by most cells in the body. They carry various molecules, including proteins, lipids, mRNA, and other RNA species, such as long non-coding RNA, circular RNA, and microRNA (miRNA). miRNAs are the most numerous cargo molecules in the exosome. They are endogenous non-coding RNA molecules, approximately 19–22-nt-long, and important regulators of protein biosynthesis. Exosomes can be taken up by neighboring or distant cells, where they play a role in post-transcriptional regulation of gene expression by targeting mRNA. Exosomal miRNAs have diverse functions, such as participation in inflammatory reactions, cell migration, proliferation, apoptosis, autophagy, and epithelial–mesenchymal transition. There is increasing evidence that exosomal miRNAs play an important role in cardiovascular health. Exosomal miRNAs are widely involved in the occurrence and development of cardiovascular diseases, such as atherosclerosis, acute coronary syndrome, heart failure (HF), myocardial ischemia reperfusion injury, and pulmonary hypertension. In this review, we present a systematic overview of the research progress into the role of exosomal miRNAs in cardiovascular diseases, and present new ideas for the diagnosis and treatment of cardiovascular diseases.

Signalling pathways implicated in the pathogenesis of rheumatic heart disease (Review)

Rheumatic heart disease (RHD) is frequently encountered in underdeveloped areas and primarily affects patients under the age of 40 years old. The pathogenesis of RHD has yet to be fully elucidated and surgical treatment remains the only option, which is expensive and technically demanding for patients in less developed areas. Signalling pathways are crucial for the occurrence and development of several diseases, and researchers worldwide have made progress in elucidating the signalling pathways associated with the pathogenesis of RHD. The aim of the present review was to discuss 6 signalling pathways implicated in the pathogenesis of RHD, summarize the methods and progress of these studies and propose future research directions. Important information on the pathogenesis of RHD according to the current progress of signalling pathway studies was also summarized, in the hope that this review may serve as a reference for future research on the signalling pathways involved in the pathogenesis of RHD.

Activation of activin/Smad2 and 3 signaling pathway and the potential involvement of endothelial‑mesenchymal transition in the valvular damage due to rheumatic heart disease

Rheumatic heart disease (RHD) is an autoimmune disease caused by rheumatic fever following group A hemolytic streptococcal infection and primarily affects the mitral valve. RHD is currently a major global health problem. However, the exact pathological mechanisms associated with RHD-induced cardiac valve damage remain to be elucidated. The endothelial-mesenchymal transition (EndMT) serves a key role in a number of diseases with an important role in cardiac fibrosis and the activin/Smad2 and 3 signaling pathway is involved in regulating the EndMT. Nevertheless, there are no studies to date, to the best of the authors' knowledge, investigating the association between RHD and EndMT. Thus, the aim of the current study was to investigate the potential role of EndMT in cardiac valve damage and assess whether activin/Smad2 and 3 signaling was activated during RHD-induced valvular injury in a rat model of RHD induced by inactivated Group A streptococci and complete Freund's adjuvant. Inflammation and fibrosis were assessed by hematoxylin and eosin and Sirius red staining. Serum cytokine and rheumatoid factor levels were measured using ELISA kits. Expression levels of activin/Smad2 and 3 signaling pathway-related factors [activin A, Smad2, Smad3, phosphorylated (p-)Smad2 and p-Smad3], EndMT-related factors [lymphoid enhancer factor-1 (LEF-1), Snail1, TWIST, zinc finger E-box-binding homeobox (ZEB)1, ZEB2, α smooth muscle actin (α-SMA) and type I collagen α 1 (COL1A1)], apoptosis-related markers (BAX and cleaved caspase-3) and valvular inflammation markers (NF-κB and p-NF-κB) were detected using reverse transcription-quantitative PCR and western blot analyses. Compared with the control group, the degree of valvular inflammation and fibrosis, serum levels of IL-6, IL-17, TNF-α and expression of apoptosis-related markers (BAX and cleaved caspase-3) and valvular inflammation marker (p-NF-κB), activin/Smad2 and 3 signaling pathway-related factors (activin A, p-Smad2 and p-Smad3), EndMT-related factors (LEF-1, Snail1, TWIST, ZEB 1, ZEB2, α-SMA and COL1A1) were significantly increased in the RHD group. These results suggested that the activin/Smad2 and 3 signaling pathway was activated during the development of valvular damage caused by RHD and that the EndMT is involved in RHD-induced cardiac valve damage.

Inhibition of miR‑155‑5p attenuates the valvular damage induced by rheumatic heart disease

Autoimmunity is involved in the valvular damage caused by rheumatic heart disease (RHD). Increased evidence has linked microRNAs (miRNAs/miRs) to autoimmune disease. Signal transducer and activator of transcription 3 (STAT3) and sphingosine-1-phosphate receptor 1 (S1PR1) and suppressor of cytokine signaling 1 (SOCS1) have been widely studied for their roles in autoimmunity and inflammation. Thus, the current study aims to investigate the role played by miR-155-5p in RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and interleukin (IL)-6/STAT3 signaling pathways. An RHD rat model was induced by inactivated Group A streptococci and complete Freund's adjuvant. A recombinant adeno-associated virus (AAV-miR155-inhibitor) was used to inhibit the expression of miR-155-5p in the heart. Inflammation and fibrosis were assessed by hematoxylin and eosin staining and Sirius red staining. The expression of miR-155-5p in valvular tissues and serum exosomes was detected by reverse transcription-quantitative PCR. S1PR1, SOCS1, STAT3, phosphorylated STAT3, IL-6 and IL-17 protein expression was detected by western blotting and immunohistochemistry. The relationships between miR-155-5p and S1PR1 and SOCS1 were detected by dual luciferase assays. Cytokine concentrations were measured by ELISA. The expression of miR-155-5p in valve tissues and serum exosomes was increased along with decreased S1PR1 and activated SOCS1/STAT3 signaling in the RHD model. The expression of IL-6 and IL-17 was increased in the valves and the serum. Dual luciferase assays showed that miR-155-5p directly targeted S1PR1 and SOCS1. Inhibition of valvular miR-155-5p through AAV pretreatment increased S1PR1 expression and inhibited activation of the SOCS1/STAT3 signal pathway as a result of attenuated valvular inflammation and fibrosis as well as a decrease in IL-6 and IL-17 in the valves and serum. These results suggest that inhibition of miR-155-5p can reduce RHD-induced valvular damage via the S1PR1, SOCS1/STAT3 and IL-6/STAT3 signaling pathways.