Transcriptomic Analysis of Cardiomyocyte Extracellular Vesicles in Hypertrophic Cardiomyopathy Reveals Differential snoRNA Cargo

SnoRNAs in cardiovascular development, function, and disease

Small nucleolar RNAs (snoRNAs) are emerging as important regulators of cardiovascular (patho)biology. Several roles of snoRNAs have recently been identified in heart development and congenital heart diseases, as well as their dynamic regulation in hypertrophic and dilated cardiomyopathies, coronary heart disease (CHD), myocardial infarction (MI), cardiac fibrosis, and heart failure. Furthermore, reports of changes in vesicular snoRNA expression and altered levels of circulating snoRNAs in response to cardiac stress suggest that snoRNAs also function in cardiac signaling and intercellular communication. In this review, we summarize and discuss key findings and outline the clinical potential of snoRNAs considering current challenges and gaps in the field of cardiovascular diseases (CVDs).

Oxidative stress-induced changes in the transcriptomic profile of extracellular vesicles

Extracellular vesicles (EVs) have been proposed to play dual roles in cellular homeostasis, functioning both to remove unwanted intracellular molecules, and to enable communication between cells as a means of modulating cellular responses in different physiological and pathological scenarios. EVs contain a broad range of cargoes, including multiple biotypes of RNA, which can vary depending on the cell status, and may function as signalling molecules. In this study, we carried out comparative transcriptomic analysis of Drosophila EVs and cells, demonstrating that the RNA profile of EVs is distinct from cells and shows dose-dependent changes in response to oxidative stress. We identified a high abundance of snoRNAs in EVs, alongside an enrichment of intronic and untranslated regions (UTRs) of mRNAs under stress. We also observed an increase in the relative abundance of either aberrant or modified mRNAs under stress. These findings suggest that EVs may function both for the elimination of specific cellular RNAs, and for the incorporation of RNAs that may hold signalling potential.

A contemporary review of snoRNAs in cardiovascular health: RNA modification and beyond

As cardiovascular diseases continue to be the leading cause of death worldwide, groundbreaking research is being conducted to mitigate their effects. This review looks into the potential of small nucleolar RNAs (snoRNAs) and the opportunity to use these molecular agents as therapeutic biomarkers for cardiovascular issues specific to the heart. Through an investigation of snoRNA biogenesis, functionality, and roles in cardiovascular diseases, this review relates our past and present knowledge of snoRNAs to the current scientific literature. Considering the initial discovery of snoRNAs and the studies thereafter analyzing the roles of snoRNAs in disease, we look forward to uncovering many other noncanonical functions that could lead researchers closer to finding preventive and curative solutions for cardiovascular diseases.

Physical modulation of mesenchymal stem cell exosomes: A new perspective for regenerative medicine

Mesenchymal stem cell-derived exosomes (MSC-Exo) offer promising therapeutic potential for various refractory diseases, presenting a novel therapeutic strategy. However, their clinical application encounters several obstacles, including low natural secretion, uncontrolled biological functions and inherent heterogeneity. On the one hand, physical stimuli can mimic the microenvironment dynamics where MSC-Exo reside. These factors influence not only their secretion but also, significantly, their biological efficacy. Moreover, physical factors can also serve as techniques for engineering exosomes. Therefore, the realm of physical factors assumes a crucial role in modifying MSC-Exo, ultimately facilitating their clinical translation. This review focuses on the research progress in applying physical factors to MSC-Exo, encompassing ultrasound, electrical stimulation, light irradiation, intrinsic physical properties, ionizing radiation, magnetic field, mechanical forces and temperature. We also discuss the current status and potential of physical stimuli-affected MSC-Exo in clinical applications. Furthermore, we address the limitations of recent studies in this field. Based on this, this review provides novel insights to advance the refinement of MSC-Exo as a therapeutic approach in regenerative medicine.

Epigenetic regulation of sex dimorphism in cardiovascular health

Cardiovascular diseases (CVDs) remain the leading cause of morbidity and mortality, affecting people of all races, ages, and sexes. Substantial sex dimorphism exists in the prevalence, manifestation, and outcomes of CVDs. Understanding the role of sex hormones as well as sex-hormone-independent epigenetic mechanisms could play a crucial role in developing effective and sex-specific cardiovascular therapeutics. Existing research highlights significant disparities in sex hormones, epigenetic regulators, and gene expression related to cardiac health, emphasizing the need for a nuanced understanding of these variations between men and women. Despite these differences, current treatment approaches for CVDs often lack sex-specific considerations. A pivotal shift toward personalized medicine, informed by comprehensive insights into sex-specific DNA methylation, histone modifications, and non-coding RNA dynamics, holds the potential to revolutionize CVD management. By understanding sex-specific epigenetic complexities, independent of sex hormone influence, future cardiovascular research can be tailored to achieve effective diagnostic and therapeutic interventions for both men and women. This review summarizes the current knowledge and gaps in epigenetic mechanisms and sex dimorphism implicated in CVDs.

Unraveling the Signaling Dynamics of Small Extracellular Vesicles in Cardiac Diseases

Effective intercellular communication is essential for cellular and tissue balance maintenance and response to challenges. Cellular communication methods involve direct cell contact or the release of biological molecules to cover short and long distances. However, a recent discovery in this communication network is the involvement of extracellular vesicles that host biological contents such as proteins, nucleic acids, and lipids, influencing neighboring cells. These extracellular vesicles are found in body fluids; thus, they are considered as potential disease biomarkers. Cardiovascular diseases are significant contributors to global morbidity and mortality, encompassing conditions such as ischemic heart disease, cardiomyopathies, electrical heart diseases, and heart failure. Recent studies reveal the release of extracellular vesicles by cardiovascular cells, influencing normal cardiac function and structure. However, under pathological conditions, extracellular vesicles composition changes, contributing to the development of cardiovascular diseases. Investigating the loading of molecular cargo in these extracellular vesicles is essential for understanding their role in disease development. This review consolidates the latest insights into the role of extracellular vesicles in diagnosis and prognosis of cardiovascular diseases, exploring the potential applications of extracellular vesicles in personalized therapies, shedding light on the evolving landscape of cardiovascular medicine.

E3 Ubiquitin Ligase Uhrf2 Knockout Reveals a Critical Role in Social Behavior and Synaptic Plasticity in the Hippocampus

The hippocampal formation, particularly the CA2 subregion, is critical for social memory formation and memory processing, relying on synaptic plasticity-a fundamental mechanism by which synapses strengthen. Given the role of the ubiquitin-proteasome system (UPS) in various nervous system processes, including learning and memory, we were particularly interested in exploring the involvement of RING-type ubiquitin E3 ligases, such as UHRF2 (NIRF), in social behavior and synaptic plasticity. Our results revealed altered social behavior in mice with systemic Uhrf2 knockout, including changes in nest building, tube dominance, and the three-chamber social novelty test. In Uhrf2 knockout mice, the entorhinal cortex-CA2 circuit showed significant reductions in synaptic plasticity during paired-pulse facilitation and long-term potentiation, while the inability to evoke synaptic plasticity in the Schaffer-collateral CA2 synapses remained unaffected. These changes in synaptic plasticity correlated with significant changes in gene expression including genes related to vesicle trafficking and transcriptional regulation. The effects of Uhrf2 knockout on synaptic plasticity and the observed gene expression changes highlight UHRF2 as a regulator of learning and memory processes at both the cellular and systemic levels. Targeting E3 ubiquitin ligases, such as UHRF2, may hold therapeutic potential for memory-related disorders, warranting further investigation.

Extracellular vesicles in cardiomyopathies: A narrative review

Extracellular vesicles (EVs) are membrane-bound particles released by all cells under physiological and pathological conditions. EVs constitute a potential tool to unravel cell-specific pathophysiological mechanisms at the root of disease states and retain the potential to act as biomarkers for cardiac diseases. By being able to carry bioactive cargo (such as proteins and miRNAs), EVs harness great potential as accessible "liquid biopsies", given their ability to reflect the state of their cell of origin. Cardiomyopathies encompass a variety of myocardial disorders associated with mechanical, functional and/or electric dysfunction. These diseases exhibit different phenotypes, including inappropriate ventricular hypertrophy, dilatation, scarring, fibro-fatty replacement, dysfunction, and may stem from multiple aetiologies, most often genetic. Thus, the aims of this narrative review are to summarize the current knowledge on EVs and cardiomyopathies (e.g., hypertrophic, dilated and arrhythmogenic), to elucidate the potential role of EVs in the paracrine cell-to-cell communication among cardiac tissue compartments, in aiding the diagnosis of the diverse subtypes of cardiomyopathies in a minimally invasive manner, and finally to address whether certain molecular and phenotypical characteristics of EVs may correlate with cardiomyopathy disease phenotype and severity.

Small but strong: the emerging role of small nucleolar RNA in cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of mortality and disability worldwide. Numerous studies have demonstrated that non-coding RNAs (ncRNAs) play a primary role in CVD development. Therefore, studies on the mechanisms of ncRNAs are essential for further efforts to prevent and treat CVDs. Small nucleolar RNAs (snoRNAs) are a novel species of non-conventional ncRNAs that guide post-transcriptional modifications and the subsequent maturation of small nuclear RNA and ribosomal RNA. Evidently, snoRNAs are extensively expressed in human tissues and may regulate different illnesses. Particularly, as the next-generation sequencing techniques have progressed, snoRNAs have been shown to be differentially expressed in CVDs, suggesting that they may play a role in the occurrence and progression of cardiac illnesses. However, the molecular processes and signaling pathways underlying the function of snoRNAs remain unidentified. Therefore, it is of great value to comprehensively investigate the association between snoRNAs and CVDs. The aim of this review was to collate existing literature on the biogenesis, characteristics, and potential regulatory mechanisms of snoRNAs. In particular, we present a scientific update on these snoRNAs and their relevance to CVDs in an effort to cast new light on the functions of snoRNAs in the clinical diagnosis of CVDs.

The good, the bad and the ugly: the impact of extracellular vesicles on the cardiovascular system

Cardiovascular diseases (CVDs), which encompass a myriad of pathological conditions that affect the heart and/or the blood vessels, remain the major cause of morbidity and mortality worldwide. By transferring a wide variety of bioactive molecules, including proteins and microRNAs (miRNAs), extracellular vesicles (EVs) are recognized as key players in long-range communication across the cardiovascular system. It has been demonstrated that these highly heterogeneous nanosized vesicles participate both in the maintenance of homeostasis of the heart and vessels, and contribute to the pathophysiology of CVDs, thus emerging as promising tools for diagnosis, prognosis and treatment of multiple CVDs. In this review, we highlight the beneficial roles of EV-mediated communication in regulating vascular homeostasis, and inter-organ crosstalk as a potential mechanism controlling systemic metabolic fitness. In addition, the impact of EV secretion in disease development is described, particularly focusing on cardiac remodelling following ischaemia, atherogenesis and atrial fibrillation progression. Finally, we discuss the potential of endogenous and bioengineered EVs as therapeutic tools for CVDs, as well as the suitability of assessing the molecular signature of circulating EVs as a non-invasive predictive marker of CVD onset and progression. This rapidly expanding field of research has established the role of EVs as key conveyors of both cardioprotective and detrimental signals, which might be of relevance in uncovering novel therapeutic targets and biomarkers of CVDs.

Enhancing the Cellular Production of Extracellular Vesicles for Developing Therapeutic Applications

Extracellular vesicles (EVs) have various advantageous properties, including a small size, high biocompatibility, efficient cargo loading, and precise cell targeting ability, making them promising tools for therapeutic development. EVs have been increasingly explored for applications like drug delivery. However, due to limited cellular secretion rates of EVs, wide-scale clinical applications are not achievable. Therefore, substantial strategies and research efforts have been devoted to increasing cellular secretion rates of EVs. This review describes various studies exploring different methods to increase the cellular production of EVs, including the application of electrical stimulus, pharmacologic agents, electromagnetic waves, sound waves, shear stress, cell starvation, alcohol, pH, heat, and genetic manipulation. These methods have shown success in increasing EV production, but careful consideration must be given as many of these strategies may alter EV properties and functionalities, and the exact mechanisms causing the increase in cellular production of EVs is generally unknown. Additionally, the methods' effectiveness in increasing EV secretion may diverge with different cell lines and conditions. Further advancements to enhance EV biogenesis secretion for therapeutic development is still a significant need in the field.

Change of Heart: the Epitranscriptome of Small Non-coding RNAs in Heart Failure

Purpose of Review

Small non-coding RNAs regulate gene expression and are highly implicated in heart failure. Recently, an additional level of post-transcriptional regulation has been identified, referred to as the epitranscriptome, which encompasses the body of post-transcriptional modifications that are placed on RNA molecules. In this review, we summarize the current knowledge on the small non-coding RNA epitranscriptome in heart failure.

Recent Findings

With the rise of new methods to study RNA modifications, epitranscriptome research has begun to take flight. Over the past 3 years, the number of publications on the epitranscriptome in heart failure has significantly increased, and we expect many more highly relevant publications to come out over the next few years.

Summary

Currently, at least six modifications on small non-coding RNAs have been investigated in heart failure-relevant studies, namely N6-adenosine, N5-cytosine and N7-guanosine methylation, 2’-O-ribose-methylation, adenosine-to-inosine editing, and isomiRs. Their potential role in heart failure is discussed.

Spaceflight-Associated Changes of snoRNAs in Peripheral Blood Mononuclear Cells and Plasma Exosomes-A Pilot Study

During spaceflight, astronauts are exposed to various physiological and psychological stressors that have been associated with adverse health effects. Therefore, there is an unmet need to develop novel diagnostic tools to predict early alterations in astronauts' health. Small nucleolar RNA (snoRNA) is a type of short non-coding RNA (60-300 nucleotides) known to guide 2'-O-methylation (Nm) or pseudouridine (ψ) of ribosomal RNA (rRNA), small nuclear RNA (snRNA), or messenger RNA (mRNA). Emerging evidence suggests that dysregulated snoRNAs may be key players in regulating fundamental cellular mechanisms and in the pathogenesis of cancer, heart, and neurological disease. Therefore, we sought to determine whether the spaceflight-induced snoRNA changes in astronaut's peripheral blood (PB) plasma extracellular vesicles (PB-EV) and peripheral blood mononuclear cells (PBMCs). Using unbiased small RNA sequencing (sRNAseq), we evaluated changes in PB-EV snoRNA content isolated from astronauts (n = 5/group) who underwent median 12-day long Shuttle missions between 1998 and 2001. Using stringent cutoff (fold change > 2 or log2-fold change >1, FDR < 0.05), we detected 21 down-and 9-up-regulated snoRNAs in PB-EVs 3 days after return (R + 3) compared to 10 days before launch (L-10). qPCR validation revealed that SNORA74A was significantly down-regulated at R + 3 compared to L-10. We next determined snoRNA expression levels in astronauts' PBMCs at R + 3 and L-10 (n = 6/group). qPCR analysis further confirmed a significant increase in SNORA19 and SNORA47 in astronauts' PBMCs at R + 3 compared to L-10. Notably, many downregulated snoRNA-guided rRNA modifications, including four Nms and five ψs. Our findings revealed that spaceflight induced changes in PB-EV and PBMCs snoRNA expression, thus suggesting snoRNAs may serve as potential novel biomarkers for monitoring astronauts' health.

Unpacking extracellular vesicles: RNA cargo loading and function

Extracellular vesicles (EVs) are a heterogeneous group of membrane-enclosed structures produced by prokaryotic and eukaryotic cells. EVs carry a range of biological cargoes, including RNA, protein, and lipids, which may have both metabolic significance and signalling potential. EV release has been suggested to play a critical role in maintaining intracellular homeostasis by eliminating unnecessary biological material from EV producing cells, and as a delivery system to enable cellular communication between both neighbouring and distant cells without physical contact. In this review, we give an overview of what is known about the relative enrichment of the different types of RNA that have been associated with EVs in the most recent research efforts. We then examine the selective and non-selective incorporation of these different RNA biotypes into EVs, the molecular systems of RNA sorting into EVs that have been elucidated so far, and the role of this process in EV-producing cells. Finally, we also discuss the model systems providing evidence for EV-mediated delivery of RNA to recipient cells, and the implications of this evidence for the relevance of this RNA delivery process in both physiological and pathological scenarios.