Transforming growth factor-β-induced endothelial-to-mesenchymal transition is partly mediated by microRNA-21

Current concepts in the epigenetic regulation of cardiac fibrosis

Cardiac fibrosis is a significant driver of congestive heart failure, a syndrome that continues to affect a growing patient population globally. Cardiac fibrosis results from a constellation of complex processes at the transcription, receptor, and signaling axes levels. Various mediators and signaling cascades, such as the transformation growth factor-beta pathway, have been implicated in the pathophysiology of cardiac tissue fibrosis. Our understanding of these markers and pathways has improved in recent years as more advanced technologies and assays have been developed, allowing for better delineation of the crosstalk between specific factors. There is mounting evidence suggesting that epigenetic modulation plays a pivotal role in the progression of cardiac fibrosis. Transcriptional regulation of key pro- and antifibrotic pathways can accentuate or blunt the rate and extent of fibrosis at the tissue level. Exosomes, micro-RNAs, and long noncoding RNAs all belong to factors that can impact the epigenetic signature in cardiac fibrosis. Herein, we comprehensively review the latest literature about exosomes, their contents, and cardiac fibrosis. In doing so, we highlight the specific transcriptional factors with pro- or antifibrotic properties. We also assimilate the data supporting these mediators' potential utility as diagnostic or prognostic biomarkers. Finally, we offer insight into where further work can be done to fill existing gaps to translate preclinical findings better and improve clinical outcomes.

Possible mechanisms of SARS-CoV-2-associated myocardial fibrosis: reflections in the post-pandemic era

Since December 2019, coronavirus disease 2019 (COVID-19) has been spreading worldwide with devastating immediate or long-term effects on people's health. Although the lungs are the primary organ affected by COVID-19, individuals infected with SARS-CoV-2 also develop systemic lesions involving multiple organs throughout the body, such as the cardiovascular system. Emerging evidence reveals that COVID-19 could generate myocardial fibrosis, termed "COVID-19-associated myocardial fibrosis." It can result from the activation of fibroblasts via the renin-angiotensin-aldosterone system (RAAS), transforming growth factor-β1 (TGF-β1), microRNAs, and other pathways, and can also occur in other cellular interactions with SARS-CoV-2, such as immunocytes, endothelial cells. Nonetheless, to gain a more profound insight into the natural progression of COVID-19-related myocardial fibrosis, additional investigations are necessary. This review delves into the underlying mechanisms contributing to COVID-19-associated myocardial fibrosis while also examining the antifibrotic potential of current COVID-19 treatments, thereby offering guidance for future clinical trials of these medications. Ultimately, we propose future research directions for COVID-19-associated myocardial fibrosis in the post-COVID-19 era, such as artificial intelligence (AI) telemedicine. We also recommend that relevant tests be added to the follow-up of COVID-19 patients to detect myocardial fibrosis promptly.

VCAM-1 targeted nanocarriers of shRNA-Smad3 mitigate endothelial-to-mesenchymal transition triggered by high glucose concentrations and osteogenic factors in valvular endothelial cells

Endothelial to mesenchymal transition (EndMT) of valvular endothelial cells (VEC) is a key process in the development and progression of calcific aortic valve disease (CAVD). High expression of the Smad3 transcription factor is crucial in the transition process. We hypothesize that silencing Smad3 could hinder EndMT and provide a novel treatment for CAVD. We aimed at developing nanoparticles encapsulating short-hairpin (sh)RNA sequences specific for Smad3 targeted to the aortic valve. We synthesized VCAM-1-targeted lipopolyplexes encapsulating shRNA-Smad3 plasmid (V-LPP/shSmad3) and investigated their potential to reduce the EndMT of human VEC. VEC incubation in a medium containing high glucose concentrations and osteogenic factors (HGOM) triggers EndMT and increased expression of Smad3. Exposed to lipopolyplexes, VEC took up efficiently the V-LPP/shSmad3. The latter reduced the EndMT process in VEC exposed to HGOM by downregulating the expression of αSMA and S100A4 mesenchymal markers and increasing the expression of the CD31 endothelial marker. In vivo, V-LPP/shSmad3 accumulated in the aortic root and aorta of a murine model of atherosclerosis complicated with diabetes, without affecting the liver and kidney function. The results suggest that targeting activated VEC with lipopolyplexes to silence Smad3 could be an effective, novel treatment for CAVD mediated by the EndMT process.

Pulmonary Hypertension and Right Ventricle: A Pathophysiological Insight

Background

Pulmonary hypertension (PH) is a pulmonary vascular disease characterized by elevated pulmonary vascular pressure. Long-term PH, irrespective of its etiology, leads to increased right ventricular (RV) pressure, RV hypertrophy, and ultimately, RV failure.

Main body

Research indicates that RV failure secondary to hypertrophy remains the primary cause of mortality in pulmonary arterial hypertension (PAH). However, the impact of PH on RV structure and function under increased overload remains incompletely understood. Several mechanisms have been proposed, including extracellular remodeling, RV hypertrophy, metabolic disturbances, inflammation, apoptosis, autophagy, endothelial-to-mesenchymal transition, neurohormonal dysregulation, capillary rarefaction, and ischemia.

Conclusions

Studies have demonstrated the significant role of oxidative stress in the development of RV failure. Understanding the interplay among these mechanisms is crucial for the prevention and management of RV failure in patients with PH.

Beyond VICs: Shedding light on the overlooked VECs in calcific aortic valve disease

Calcific aortic valve disease (CAVD) is prevalent in developed nations and has emerged as a pressing global public health concern due to population aging. The precise etiology of this disease remains uncertain, and recent research has primarily focused on examining the role of valvular interstitial cells (VICs) in the development of CAVD. The predominant treatment options currently available involve open surgery and minimally invasive interventional surgery, with no efficacious pharmacological treatment. This article seeks to provide a comprehensive understanding of valvular endothelial cells (VECs) from the aspects of valvular endothelium-derived nitric oxide (NO), valvular endothelial mechanotransduction, valvular endothelial injury, valvular endothelial-mesenchymal transition (EndMT), and valvular neovascularization, which have received less attention, and aims to establish their role and interaction with VICs in CAVD. The ultimate goal is to provide new perspectives for the investigation of non-invasive treatment options for this disease.

The role of cancer-associated fibroblasts and exosomal miRNAs-mediated intercellular communication in the tumor microenvironment and the biology of carcinogenesis: a systematic review

CAFs (cancer-associated fibroblasts) are highly flexible cells of the cancer microenvironment. They produce the extracellular matrix (ECM) constituents that form the structure of the tumor stroma but are also a source of metabolites, growth factors, chemokines, and exosomes that impact every aspect of the tumor, including its response to treatment. It is believed that exosomal miRNAs facilitate intercellular signaling, which is essential for the development of cancer. The role of miRNAs and CAFs in the tumor microenvironment (TME) and carcinogenesis is reviewed in this paper. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 guidelines were used to perform a systematic review. Several databases, including Web of Science, Medline, Embase, Cochrane Library, and Scopus, were searched using the following keywords: CAFs, CAF, cancer-associated fibroblasts, stromal fibroblasts, miRNA, exosomal miRNAs, exosome and similar terms. We identified studies investigating exosomal miRNAs and CAFs in the TME and their role in carcinogenesis. A total of 12,572 papers were identified. After removing duplicates (n = 3803), 8774 articles were screened by title and abstract. Of these, 421 were excluded from further analysis. It has been reported that if exosomal miRNAs in CAFs are not functioning correctly, this may influence the secretory phenotype of tip cells and contribute to increased tumor invasiveness, tumor spread, decreased treatment efficacy, and a poorer prognosis. Under their influence, normal fibroblasts (NFs) are transformed into CAFs. Furthermore, they participate in metabolic reprogramming, which allows for fast proliferation of the cancer cell population, adaptation to growing energy demands, and the capacity to avoid immune system identification.

Pathophysiology in Brain Arteriovenous Malformations: Focus on Endothelial Dysfunctions and Endothelial-to-Mesenchymal Transition

Brain arteriovenous malformations (bAVMs) substantially increase the risk for intracerebral hemorrhage (ICH), which is associated with significant morbidity and mortality. However, the treatment options for bAVMs are severely limited, primarily relying on invasive methods that carry their own risks for intraoperative hemorrhage or even death. Currently, there are no pharmaceutical agents shown to treat this condition, primarily due to a poor understanding of bAVM pathophysiology. For the last decade, bAVM research has made significant advances, including the identification of novel genetic mutations and relevant signaling in bAVM development. However, bAVM pathophysiology is still largely unclear. Further investigation is required to understand the detailed cellular and molecular mechanisms involved, which will enable the development of safer and more effective treatment options. Endothelial cells (ECs), the cells that line the vascular lumen, are integral to the pathogenesis of bAVMs. Understanding the fundamental role of ECs in pathological conditions is crucial to unraveling bAVM pathophysiology. This review focuses on the current knowledge of bAVM-relevant signaling pathways and dysfunctions in ECs, particularly the endothelial-to-mesenchymal transition (EndMT).

Multiscale computational modeling of aortic valve calcification

Calcific aortic valve disease (CAVD) is a common cardiovascular disease that affects millions of people worldwide. The disease is characterized by the formation of calcium nodules on the aortic valve leaflets, which can lead to stenosis and heart failure if left untreated. The pathogenesis of CAVD is still not well understood, but involves several signaling pathways, including the transforming growth factor beta (TGF β ) pathway. In this study, we developed a multiscale computational model for TGF β -stimulated CAVD. The model framework comprises cellular behavior dynamics, subcellular signaling pathways, and tissue-level diffusion fields of pertinent chemical species, where information is shared among different scales. Processes such as endothelial to mesenchymal transition (EndMT), fibrosis, and calcification are incorporated. The results indicate that the majority of myofibroblasts and osteoblast-like cells ultimately die due to lack of nutrients as they become trapped in areas with higher levels of fibrosis or calcification, and they subsequently act as sources for calcium nodules, which contribute to a polydispersed nodule size distribution. Additionally, fibrosis and calcification processes occur more frequently in regions closer to the endothelial layer where the cell activity is higher. Our results provide insights into the mechanisms of CAVD and TGF β signaling and could aid in the development of novel therapeutic approaches for CAVD and other related diseases such as cancer. More broadly, this type of modeling framework can pave the way for unraveling the complexity of biological systems by incorporating several signaling pathways in subcellular models to simulate tissue remodeling in diseases involving cellular mechanobiology.

miR-21 Expressed by Dermal Fibroblasts Enhances Skin Wound Healing Through the Regulation of Inflammatory Cytokine Expression

The management of skin wound healing is still a challenge. MicroRNA-21 (miR-21) has been reported to play important roles in wound repair; however, the underlying mechanism needs to be further clarified. The present study aimed to study the direct role of miR-21 in skin wound healing in miR-21 KO mice and to investigate the role of miR-21 in controlling the migration and proliferation of primary human skin cells and its underlying mechanism(s). miR-21 KO and wild-type (WT) mice were used for in vivo wound healing assays, while mouse and human primary skin cells were used for in vitro assays. miR-21 inhibitors or mimics or negative control small RNAs were transfected to either inhibit or enhance miR-21 expression in the human primary dermal fibroblasts or epidermal cells. RNA sequencing analysis was performed to identify the potential molecular pathways involved. We found that the loss of miR-21 resulted in slower wound healing in miR-21 KO mouse skin and especially delayed the healing of dermal tissue. In vitro assays demonstrated that the reduced expression of miR-21 caused by its inhibitor inhibited the migration of human primary dermal fibroblasts, which could be enhanced by increased miR-21 expression caused by miR-21 mimics. RNA-sequence analysis revealed that the inhibition of miR-21 expression downregulated the inflammatory response pathways associated with the decreased expression of inflammatory cytokines, and the addition of IL-1β into the culture medium enhanced the migration and proliferation of dermal fibroblasts in vitro. In conclusion, miR-21 in dermal fibroblasts can promote the migration and growth of epidermal and dermal cells to enhance skin wound healing through controlling the expression of inflammatory cytokines.

Long non-coding RNAs as emerging regulators of miRNAs and epigenetics in diabetes-related chronic kidney disease

Diabetes is one of the major cause of chronic kidney disease (CKD), including "diabetic nephropathy," and is an increasingly prevalent accelerator of the progression of non-diabetic forms of CKD. The long non-coding RNAs (lncRNAs) have come into the limelight in the past few years as one of the emerging weapons against CKD in diabetes. Available data over the past few years demonstrate the interaction of lncRNAs with miRNAs and epigenetic machinery. Interestingly, the evolving data suggest that lncRNAs play a vital role in diabetes-associated CKD by regulation of epigenetic enzymes such as DNA methyltransferase, histone deacetylases, and histone methyltransferases. LncRNAs are also engaged in the regulation of several miRNAs in diabetic nephropathy. Hence this review will elaborate on the association between lncRNAs and their interaction with epigenetic regulators involved in different aspects and thus the progression of CKD in diabetes.

miRNAs in Heart Development and Disease

Cardiovascular diseases (CVD) are a group of disorders that affect the heart and blood vessels. They include conditions such as myocardial infarction, coronary artery disease, heart failure, arrhythmia, and congenital heart defects. CVDs are the leading cause of death worldwide. Therefore, new medical interventions that aim to prevent, treat, or manage CVDs are of prime importance. MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the posttranscriptional level and play important roles in various biological processes, including cardiac development, function, and disease. Moreover, miRNAs can also act as biomarkers and therapeutic targets. In order to identify and characterize miRNAs and their target genes, scientists take advantage of computational tools such as bioinformatic algorithms, which can also assist in analyzing miRNA expression profiles, functions, and interactions in different cardiac conditions. Indeed, the combination of miRNA research and bioinformatic algorithms has opened new avenues for understanding and treating CVDs. In this review, we summarize the current knowledge on the roles of miRNAs in cardiac development and CVDs, discuss the challenges and opportunities, and provide some examples of recent bioinformatics for miRNA research in cardiovascular biology and medicine.

Inhibitory effect of microRNA-21 on pathways and mechanisms involved in cardiac fibrosis development

Cardiac fibrosis is a pivotal cardiovascular disease (CVD) process and represents a notable health concern worldwide. While the complex mechanisms underlying CVD have been widely investigated, recent research has highlighted microRNA-21's (miR-21) role in cardiac fibrosis pathogenesis. In this narrative review, we explore the molecular interactions, focusing on the role of miR-21 in contributing to cardiac fibrosis. Various signaling pathways, such as the RAAS, TGF-β, IL-6, IL-1, ERK, PI3K-Akt, and PTEN pathways, besides dysregulation in fibroblast activity, matrix metalloproteinases (MMPs), and tissue inhibitors of MMPs cause cardiac fibrosis. Besides, miR-21 in growth factor secretion, apoptosis, and endothelial-to-mesenchymal transition play crucial roles. miR-21 capacity regulatory function presents promising insights for cardiac fibrosis. Moreover, this review discusses numerous approaches to control miR-21 expression, including antisense oligonucleotides, anti-miR-21 compounds, and Notch signaling modulation, all novel methods of cardiac fibrosis inhibition. In summary, this narrative review aims to assess the molecular mechanisms of cardiac fibrosis and its essential miR-21 function.

Interplay Between TGF-β Signaling and MicroRNA in Diabetic Cardiomyopathy

In diabetic patients, concomitant cardiovascular disease is the main factor contributing to their morbidity and mortality. Diabetic cardiomyopathy (DCM) is a form of cardiovascular disease associated with diabetes that can result in heart failure. Transforming growth factor-β (TGF-β) isoforms play a crucial role in heart remodeling and repair and are elevated and activated in myocardial disorders. Alterations in certain microRNAs (miRNA) are closely related to diabetic cardiomyopathy. One or more miRNA molecules target the majority of TGF-β pathway components, and TGF-β directly or via SMADs controls miRNA synthesis. Based on these interactions, this review discusses potential cross-talk between TGF-β signaling and miRNA in DCM in order to investigate the creation of potential therapeutic targets.

Exosomal miR-218 derived from mesenchymal stem cells inhibits endothelial-to-mesenchymal transition by epigenetically modulating of BMP2 in pulmonary fibrosis

Endothelial-to-mesenchymal transition (EndMT), the process by which endothelial cells lose their characteristics and acquire mesenchymal phenotypes, participates in the pathogenic mechanism of idiopathic pulmonary fibrosis. Recently, exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-Exos) has been introduced as a promising treatment in organ fibrosis. This study aimed to explore the effects as well as the molecular mechanism for hucMSC-Exo in pulmonary fibrosis. The intravenous administration of hucMSC-Exos alleviated bleomycin-induced pulmonary fibrosis in vivo. Moreover, hucMSC-Exos elevated miR-218 expression and restored endothelial properties weakened by TGF-β in endothelial cells. Knockdown of miR-218 partially abrogated the inhibition effect of hucMSC-Exos on EndMT. Our mechanistic study further demonstrated that MeCP2 was the direct target of miR-218. Overexpressing MeCP2 aggravated EndMT and caused increased CpG islands methylation at BMP2 promoter, which lead to BMP2 post-transcriptional gene silence. Transfection of miR-218 mimic increased BMP2 expression as well, which was downregulated by overexpression of MeCP2. Taken together, these findings indicate exosomal miR-218 derived from hucMSCs may possess anti-fibrotic properties and inhibit EndMT through MeCP2/BMP2 pathway, providing a new avenue of preventive application in pulmonary fibrosis.

miR-632 Induces DNAJB6 Inhibition Stimulating Endothelial-to-Mesenchymal Transition and Fibrosis in Marfan Syndrome Aortopathy

Marfan syndrome (MFS) is a connective tissue disorder caused by FBN1 gene mutations leading to TGF-β signaling hyperactivation, vascular wall weakness, and thoracic aortic aneurysms (TAAs). The pathogenetic mechanisms are not completely understood and patients undergo early vascular surgery to prevent TAA ruptures. We previously reported miR-632 upregulation in MFS TAA tissues compared with non-genetic TAA tissues. DNAJB6 is a gene target of miR-632 in cancer and plays a critical role in blocking epithelial-to-mesenchymal transition by inhibiting the Wnt/β catenin pathway. TGF-β signaling also activates Wnt/β catenin signaling and induces endothelial-to-mesenchymal transition (End-Mt) and fibrosis. We documented that miR-632 upregulation correlated with DNAJB6 expression in both the endothelium and the tunica media of MFS TAA (p < 0.01). Wnt/β catenin signaling, End-Mt, and fibrosis markers were also upregulated in MFS TAA tissues (p < 0.05, p < 0.01 and p < 0.001). Moreover, miR-632 overexpression inhibited DNAJB6, inducing Wnt/β catenin signaling, as well as End-Mt and fibrosis exacerbation (p < 0.05 and p < 0.01). TGF-β1 treatment also determined miR-632 upregulation (p < 0.01 and p < 0.001), with the consequent activation of the aforementioned processes. Our study provides new insights about the pathogenetic mechanisms in MFS aortopathy. Moreover, the high disease specificity of miR-632 and DNAJB6 suggests new potential prognostic factors and/or therapeutic targets in the progression of MFS aortopathy.

Paricalcitol improved cardiac hypertrophy and fibrosis through upregulation of fibroblast growth factor-23 and downregulation of transforming growth factor-beta in a rat model of isoproterenol-induced cardiomyopathy

Acute cardiomyopathy is a significant global health concern and one of the leading causes of death in developed countries. Prior studies have shown an association between acute cardiomyopathy and low vitamin D levels. Although paricalcitol, a vitamin D receptor (VDR) activator, has demonstrated clinical benefits in patients with advanced kidney disease, its effect on cardiac remodeling in cardiomyopathy is unknown. This study aimed to investigate the relative effects of paricalcitol on cardiomyopathy in rats. Wistar-Kyoto rats were administered vehicle (sham control group) or isoproterenol to induce cardiomyopathy. Rats administered isoproterenol were subsequently treated with paricalcitol (experimental group) or vehicle (isoproterenol group). Picrosirius red and immunofluorescence staining were used to analyze cardiac fibrosis and hypertrophy. Immunohistochemistry staining was used to confirm the molecular mechanisms involved in isoproterenol-induced cardiomyopathy in rats. Injection of paricalcitol could reduce collagen and transforming growth factor-beta 1 (TGF-β1) levels while activating fibroblast growth factor receptor 1 (FGFR1) and fibroblast growth factor-23 (FGF23) without the help of Klotho, thereby reducing myocardial hypertrophy and fibrosis. As a VDR activator, paricalcitol reduces isoproterenol-induced cardiac fibrosis and hypertrophy by reducing the expression of TGF-β1 and enhancing the expression of VDR, FGFR1, and FGF23.

ONX0914 inhibition of immunoproteasome subunit LMP7 ameliorates diabetic cardiomyopathy via restraining endothelial-mesenchymal transition

Diabetic cardiomyopathy (DCM) is a chronic metabolic disease with few effective therapeutic options. Immunoproteasome is an inducible proteasome that plays an important role in the regulation of many cardiovascular diseases, while its role in DCM remains under discussion. The present study aims to demonstrate whether inhibiting immunoproteasome subunit low molecular weight polypeptide 7 (LMP7) could alleviate DCM. Here, we established a type I diabetes mellitus mouse model by streptozotocin (STZ) in 8-week-old male wild-type C57BL/6J mice. We found that immunoproteasome subunit LMP7 was overexpressed in the heart of diabetic mice, while inhibiting LMP7 with pharmacological inhibitor ONX0914 significantly alleviated myocardial fibrosis and improved cardiac function. Besides, compared with diabetic mice, ONX0914 treatment reduced protein levels of mesenchymal markers (Vimentin, α-smooth muscle actin, and SM22α) and increased endothelial markers (VE-cadherin and CD31). In TGFβ1 stimulated HUVECs, we also observed that ONX0914 could inhibit endothelial-mesenchymal transition (EndMT). Mechanistically, we prove that ONX0914 could regulate autophagy activity both in vivo and vitro. Meanwhile, the protective effect of ONX0914 on TGFβ1 stimulated HUVECs could be abolished by 3-methyladenine (3MA) or hydroxychloroquine (CQ). All in all, our data highlight that inhibition of LMP7 with ONX0914 could ameliorate EndMT in diabetic mouse hearts at least in part via autophagy activation. Thus, LMP7 may be a potential therapeutic target for the DCM.

Endothelial-to-mesenchymal transition: New insights into vascular calcification

With the continuous progress of atherosclerosis research, the significant pathological change of it--vascular calcification (VC), gains increasing attention. In recent years, numerous studies have demonstrated that it is an independent predictor of death risk of cardiovascular disease, and it has a strong correlation with poor clinical prognosis. As the world's population continues to age, the occurrence of VC is expected to reach its highest point in the near future. Therefore, it is essential to investigate ways to prevent or even reverse this process for clinical purposes. Endothelial-to-mesenchymal transition (EndMT) describes the progressive differentiation of endothelial cells into mesenchymal stem cells (MSCs) under various stimuli and acquisition of pluripotent cell characteristics. More and more studies show that EndMT plays a vital role in various cardiovascular diseases, including atherosclerosis, vascular calcification and heart valvular disease. EndMT is also involved in the formation and progression of VC. This review vividly describes the history, characteristics of EndMT and how it affects the endothelial cell process, then focuses on the relationship between vascular endothelium, EndMT, amino acid metabolism, and vascular calcification. Finally, it overviews the signal pathway of EndMT and drugs targeting EndMT, hoping to provide new ideas and a theoretical basis for studying potential therapeutic targets of VC.

Possible molecular mechanisms underlying the development of atherosclerosis in cancer survivors

Cancer survivors undergone treatment face an increased risk of developing atherosclerotic cardiovascular disease (CVD), yet the underlying mechanisms remain elusive. Recent studies have revealed that chemotherapy can drive senescent cancer cells to acquire a proliferative phenotype known as senescence-associated stemness (SAS). These SAS cells exhibit enhanced growth and resistance to cancer treatment, thereby contributing to disease progression. Endothelial cell (EC) senescence has been implicated in atherosclerosis and cancer, including among cancer survivors. Treatment modalities for cancer can induce EC senescence, leading to the development of SAS phenotype and subsequent atherosclerosis in cancer survivors. Consequently, targeting senescent ECs displaying the SAS phenotype hold promise as a therapeutic approach for managing atherosclerotic CVD in this population. This review aims to provide a mechanistic understanding of SAS induction in ECs and its contribution to atherosclerosis among cancer survivors. We delve into the mechanisms underlying EC senescence in response to disturbed flow and ionizing radiation, which play pivotal role in atherosclerosis and cancer. Key pathways, including p90RSK/TERF2IP, TGFβR1/SMAD, and BH4 signaling are explored as potential targets for cancer treatment. By comprehending the similarities and distinctions between different types of senescence and the associated pathways, we can pave the way for targeted interventions aim at enhancing the cardiovascular health of this vulnerable population. The insights gained from this review may facilitate the development of novel therapeutic strategies for managing atherosclerotic CVD in cancer survivors.

MicroRNA 9 Is a Regulator of Endothelial to Mesenchymal Transition in Diabetic Retinopathy

Purpose

Diabetic retinopathy (DR) is a significant cause of blindness. Most research around DR focus on late-stage developments rather than early changes such as early endothelial dysfunction. Endothelial-to-mesenchymal transition (EndMT), an epigenetically regulated process whereby endothelial cells lose endothelial characteristics and adopt mesenchymal-like phenotypes, contributes to early endothelial changes in DR. The epigenetic regulator microRNA 9 (miR-9) is suppressed in the eyes during DR. MiR-9 plays a role in various diseases and regulates EndMT-related processes in other organs. We investigated the role miR-9 plays in glucose-induced EndMT in DR.

Methods

We examined the effects of glucose on miR-9 and EndMT using human retinal endothelial cells (HRECs). We then used HRECs and an endothelial-specific miR-9 transgenic mouse line to investigate the effect of miR-9 on glucose-induced EndMT. Finally, we used HRECs to probe the mechanisms through which miR-9 may regulate EndMT.

Results

We found that miR-9 inhibition was both necessary and sufficient for glucose-induced EndMT. Overexpression of miR-9 prevented glucose-induced EndMT, whereas suppressing miR-9 caused glucose-like EndMT changes. We also found that preventing EndMT with miR-9 overexpression improved retinal vascular leakage in DR. Finally, we showed that miR-9 regulates EndMT at an early stage by regulating EndMT-inducing signals such as proinflammatory and TGF-β pathways.

Conclusions

We have shown that miR-9 is an important regulator of EndMT in DR, potentially making it a good target for RNA-based therapy in early DR.

A comprehensive review of acute cardio-renal syndrome: need for novel biomarkers

Cardiorenal syndrome represents a wide-spectrum disorder involving the heart and kidneys as the primary affected organs. India has an increasingly high burden of acute CRS, coinciding with the rise in global statistics. Up to 2022, approximately 46.1% of all cardiorenal patients have been diagnosed with acute CRS in India. Acute CRS involves a sudden deterioration of kidney functionalities, referred to as acute kidney injury (AKI) in acute heart failure patients. The pathophysiology of CRS involves hyperactivation of the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS) following acute myocardial stress. The pathological phenotype of acute CRS is associated with perturbed inflammatory, cellular, and neurohormonal markers in circulation. These complications increase the risk of mortality in clinically diagnosed acute CRS patients, making it a worldwide healthcare burden. Hence, effective diagnosis and early prevention are crucial to prevent the progression of CRS in AHF patients. Present biomarkers, such as serum creatinine (sCr), cystatin C (CysC), glomerular filtration rate (GFR), blood urea nitrogen (BUN), serum and/or urine neutrophil gelatinase-associated lipocalin (NGAL), B-type natriuretic peptide (BNP), and NT-proBNP, are clinically used to diagnose AKI stages in CRS patients but are limitedly sensitive to the early detection of the pathology. Therefore, the need for protein biomarkers is emerging for early intervention in CRS progression. Here, we summarized the cardio-renal nexus in acute CRS, with an emphasis on the present clinicopathological biomarkers and their limitations. The objective of this review is to highlight the need for novel proteomic biomarkers that will curb the burgeoning concern and direct future research trials.

The role of endothelial cell in cardiac hypertrophy: Focusing on angiogenesis and intercellular crosstalk

Cardiac hypertrophy is characterized by cardiac structural remodeling, fibrosis, microvascular rarefaction, and chronic inflammation. The heart is structurally organized by different cell types, including cardiomyocytes, fibroblasts, endothelial cells, and immune cells. These cells highly interact with each other by a number of paracrine or autocrine factors. Cell-cell communication is indispensable for cardiac development, but also plays a vital role in regulating cardiac response to damage. Although cardiomyocytes and fibroblasts are deemed as key regulators of hypertrophic stimulation, other cells, including endothelial cells, also exert important effects on cardiac hypertrophy. More particularly, endothelial cells are the most abundant cells in the heart, which make up the basic structure of blood vessels and are widespread around other cells in the heart, implicating the great and inbuilt advantage of intercellular crosstalk. Cardiac microvascular plexuses are essential for transport of liquids, nutrients, molecules and cells within the heart. Meanwhile, endothelial cell-mediated paracrine signals have multiple positive or negative influences on cardiac hypertrophy. However, a comprehensive discussion of these influences and consequences is required. This review aims to summarize the basic function of endothelial cells in angiogenesis, with an emphasis on angiogenic molecules under hypertrophic conditions. The secondary objective of the research is to fully discuss the key molecules involved in the intercellular crosstalk and the endothelial cell-mediated protective or detrimental effects on other cardiac cells. This review provides a more comprehensive understanding of the overall role of endothelial cells in cardiac hypertrophy and guides the therapeutic approaches and drug development of cardiac hypertrophy.

microRNAs as Biomarkers of Endothelial Dysfunction and Therapeutic Target in the Pathogenesis of Atrial Fibrillation

The pathophysiology of atrial fibrillation (AF) may involve atrial fibrosis/remodeling and dysfunctional endothelial activities. Despite the currently available treatment approaches, the progression of AF, its recurrence rate, and the high mortality risk of related complications underlay the need for more advanced prognostic and therapeutic strategies. There is increasing attention on the molecular mechanisms controlling AF onset and progression points to the complex cell to cell interplay that triggers fibroblasts, immune cells and myofibroblasts, enhancing atrial fibrosis. In this scenario, endothelial cell dysfunction (ED) might play an unexpected but significant role. microRNAs (miRNAs) regulate gene expression at the post-transcriptional level. In the cardiovascular compartment, both free circulating and exosomal miRNAs entail the control of plaque formation, lipid metabolism, inflammation and angiogenesis, cardiomyocyte growth and contractility, and even the maintenance of cardiac rhythm. Abnormal miRNAs levels may indicate the activation state of circulating cells, and thus represent a specific read-out of cardiac tissue changes. Although several unresolved questions still limit their clinical use, the ease of accessibility in biofluids and their prognostic and diagnostic properties make them novel and attractive biomarker candidates in AF. This article summarizes the most recent features of AF associated with miRNAs and relates them to potentially underlying mechanisms.

Pediatric Diabetic Nephropathy: Novel Insights from microRNAs

Diabetic nephropathy (DN) represents the most common microvascular complication in patients with diabetes. This progressive kidney disease has been recognized as the major cause of end-stage renal disease with higher morbidity and mortality. However, its tangled pathophysiology is still not fully known. Due to the serious health burden of DN, novel potential biomarkers have been proposed to improve early identification of the disease. In this complex landscape, several lines of evidence supported a critical role of microRNAs (miRNAs) in regulating posttranscriptional levels of protein-coding genes involved in DN pathophysiology. Indeed, intriguing data showed that deregulation of certain miRNAs (e.g., miRNAs 21, -25, -92, -210, -126, -216, and -377) were pathogenically linked to the onset and the progression of DN, suggesting not only a role as early biomarkers but also as potential therapeutic targets. To date, these regulatory biomolecules represent the most promising diagnostic and therapeutic options for DN in adult patients, while similar pediatric evidence is still limited. More, findings from these elegant studies, although promising, need to be deeper investigated in larger validation studies. In an attempt to provide a comprehensive pediatric overview in the field, we aimed to summarize the most recent evidence on the emerging role of miRNAs in pediatric DN pathophysiology.

miR-132-3p and KLF7 as novel regulators of aortic stiffening-associated EndMT in type 2 diabetes mellitus

BACKGROUND

The prevalence of diabetes mellitus has risen considerably and currently affects more than 422 million people worldwide. Cardiovascular diseases including myocardial infarction and heart failure represent the major cause of death in type 2 diabetes (T2D). Diabetes patients exhibit accelerated aortic stiffening which is an independent predictor of cardiovascular disease and mortality. We recently showed that aortic stiffness precedes hypertension in a mouse model of diabetes (db/db mice), making aortic stiffness an early contributor to cardiovascular disease development. Elucidating how aortic stiffening develops is a pressing need in order to halt the pathophysiological process at an early time point.

METHODS

To assess EndMT occurrence, we performed co-immunofluorescence staining of an endothelial marker (CD31) with mesenchymal markers (α-SMA/S100A4) in aortic sections from db/db mice. Moreover, we performed qRT-PCR to analyze mRNA expression of EndMT transcription factors in aortic sections of db/db mice and diabetic patients. To identify the underlying mechanism by which EndMT contributes to aortic stiffening, we used aortas from db/db mice and diabetic patients in combination with high glucose-treated human umbilical vein endothelial cells (HUVECs) as an in vitro model of diabetes-associated EndMT.

RESULTS

We demonstrate robust CD31/α-SMA and CD31/S100A4 co-localization in aortic sections of db/db mice which was almost absent in control mice. Moreover, we demonstrate a significant upregulation of EndMT transcription factors in aortic sections of db/db mice and diabetic patients. As underlying regulator, we identified miR-132-3p as the most significantly downregulated miR in the micronome of db/db mice and high glucose-treated HUVECs. Indeed, miR-132-3p was also significantly downregulated in aortic tissue from diabetic patients. We identified Kruppel-like factor 7 (KLF7) as a target of miR-132-3p and show a significant upregulation of KLF7 in aortic sections of db/db mice and diabetic patients as well as in high glucose-treated HUVECs. We further demonstrate that miR-132-3p overexpression and KLF7 downregulation ameliorates EndMT in high glucose-treated HUVECs.

CONCLUSIONS

We demonstrate for the first time that EndMT contributes to aortic stiffening in T2D. We identified miR-132-3p and KLF7 as novel EndMT regulators in this context. Altogether, this gives us new insights in the development of aortic stiffening in T2D.

Hydrogen Sulfide Modulates Endothelial-Mesenchymal Transition in Heart Failure

BACKGROUND

Hydrogen sulfide is a critical endogenous signaling molecule that exerts protective effects in the setting of heart failure. Cystathionine γ-lyase (CSE), 1 of 3 hydrogen-sulfide-producing enzyme, is predominantly localized in the vascular endothelium. The interaction between the endothelial CSE-hydrogen sulfide axis and endothelial-mesenchymal transition, an important pathological process contributing to the formation of fibrosis, has yet to be investigated.

METHODS

Endothelial-cell-specific CSE knockout and Endothelial cell-CSE overexpressing mice were subjected to transverse aortic constriction to induce heart failure with reduced ejection fraction. Cardiac function, vascular reactivity, and treadmill exercise capacity were measured to determine the severity of heart failure. Histological and gene expression analyses were performed to investigate changes in cardiac fibrosis and the activation of endothelial-mesenchymal transition.

RESULTS

Endothelial-cell-specific CSE knockout mice exhibited increased endothelial-mesenchymal transition and reduced nitric oxide bioavailability in the myocardium, which was associated with increased cardiac fibrosis, impaired cardiac and vascular function, and worsened exercise performance. In contrast, genetic overexpression of CSE in endothelial cells led to increased myocardial nitric oxide, decreased endothelial-mesenchymal transition and cardiac fibrosis, preserved cardiac and endothelial function, and improved exercise capacity.

CONCLUSIONS

Our data demonstrate that endothelial CSE modulates endothelial-mesenchymal transition and ameliorate the severity of pressure-overload-induced heart failure, in part, through nitric oxide-related mechanisms. These data further suggest that endothelium-derived hydrogen sulfide is a potential therapeutic for the treatment of heart failure with reduced ejection fraction.

Endothelial-mesenchymal transition induced by metastatic 4T1 breast cancer cells in pulmonary endothelium in aged mice

Ageing is a major risk factor for cancer metastasis but the underlying mechanisms remain unclear. Here, we characterised ageing effects on cancer-induced endothelial-mesenchymal transition (EndMT) in the pulmonary circulation of female BALB/c mice in a metastatic 4T1 breast cancer model. The effect of intravenously injected 4T1 cells on pulmonary endothelium, pulmonary metastasis, lung tissue architecture, and systemic endothelium was compared between 40-week-old and 20-week-old mice. The 40-week-old mice showed features of ongoing EndMT in their lungs before 4T1 breast cancer cell injection. Moreover, they had preexisting endothelial dysfunction in the aorta detected by in vivo magnetic resonance imaging (MRI) compared to 20-week-old mice. The injection of 4T1 breast cancer cells into 40-week-old mice resulted in rapid EndMT progression in their lungs. In contrast, injection of 4T1 breast cancer cells into 20-week-old mice resulted in initiation and less pronounced EndMT progression. Although the number of metastases did not differ significantly between 20-week-old and 40-week-old mice, the lungs of older mice displayed altered lung tissue architecture and biochemical content, reflected in higher Amide II/Amide I ratio, higher fibronectin levels, and hypoxia-inducible factor 1 subunit alpha (HIF1α) levels as well as lower nitric oxide (NO) production. Our results indicate that age-dependent pre-existing endothelial dysfunction in the pulmonary endothelium of 40-week-old mice predisposed them to rapid EndMT progression in the presence of circulating 4T1 breast cancer cells what might contribute to a more severe metastatic breast cancer phenotype in these ageing mice compared to younger mice.

Enduring Reactive Oxygen Species Emission Causes Aberrant Protein S-Glutathionylation Transitioning Human Aortic Valve Cells from a Sclerotic to a Stenotic Phenotype

Aims: During calcific aortic valve stenosis (CAVS) progression, oxidative stress and endothelial dysfunction mark the initial pathogenic steps with a parallel dysregulation of the antioxidant systems. Here, we tested whether oxidation-induced protein S-glutathionylation (P-SSG) accounts for a phenotypic switch in human aortic valvular tissue, eventually leading to calcium deposition. Next, we tested whether countering this reactive oxygen species (ROS) surge would prevent these perturbations. Results: We employed state-of-the-art technologies, such as electron paramagnetic resonance (EPR), liquid chromatography-tandem mass spectrometry, imaging flow-cytometry, and live-cell imaging on human excised aortic valves and primary valve endothelial cells (VECs). We observed that a net rise in EPR-detected ROS emission marked the transition from fibrotic to calcific in human CAVS specimens, coupled to a progressive increment in P-SSG deposition. In human VECs (hVECs), treatment with 2-acetylamino-3-[4-(2-acetylamino-2-carboxyethylsulfanylthiocarbonylamino)phenylthiocarbamoylsulfanyl]propionic acid triggered highly oxidizing conditions prompting P-SSG accumulation, damaging mitochondria, and inducing endothelial nitric oxide synthase uncoupling. All the events conjured up in morphing these cells from their native endothelial phenotype into a damaged calcification-inducing one. As proof of principle, the use of the antioxidant N-acetyl-L-cysteine prevented these alterations. Innovation: Borne as a compensatory system to face excessive oxidative burden, with time, P-SSG contributes to the morphing of hVECs from their innate phenotype into a damaged one, paving the way to calcium deposition. Conclusion: Our data suggest that, in the human aortic valve, unremitted ROS emission along with a P-SSG build-up occurs and accounts, at least in part, for the morphological/functional changes leading to CAVS. Antioxid. Redox Signal. 37, 1051-1071.

Network pharmacology and experimental analysis to reveal the mechanism of Dan-Shen-Yin against endothelial to mesenchymal transition in atherosclerosis

Atherosclerosis is a chronic inflammatory disease characterized by the formation of plaque and endothelial dysfunction. Under pro-inflammatory conditions, endothelial cells adopt a mesenchymal phenotype by a process called endothelial-to-mesenchymal transition (EndMT) which plays an important role in the pathogenesis of atherosclerosis. Dan-Shen-Yin (DSY) is a well-known traditional Chinese medicine used in the treatment of cardiovascular disease. However, the molecular mechanism whereby DSY mitigates atherosclerosis remains unknown. Therefore, we employed a network pharmacology-based strategy in this study to determine the therapeutic targets of DSY, and in vitro experiments to understand the molecular pharmacology mechanism. The targets of the active ingredients of DSY related to EndMT and atherosclerosis were obtained and used to construct a protein-protein interaction (PPI) network followed by network topology and functional enrichment analysis. Network pharmacology analysis revealed that the PI3K/AKT pathway was the principal signaling pathway of DSY against EndMT in atherosclerosis. Molecular docking simulations indicated strong binding capabilities of DSY’s bioactive ingredients toward PI3K/AKT pathway molecules. Experimentally, DSY could efficiently modify expression of signature EndMT genes and decrease expression of PI3K/AKT pathway signals including integrin αV, integrin β1, PI3K, and AKT1 in TGF-β2-treated HUVECs. LASP1, which is upstream of the PI3K/AKT pathway, had strong binding affinity to the majority of DSY’s bioactive ingredients, was induced by EndMT-promoting stimuli involving IL-1β, TGF-β2, and hypoxia, and was downregulated by DSY. Knock-down of LASP1 attenuated the expression of integrin αV, integrin β1, PI3K, AKT1 and EndMT-related genes induced by TGF-β2, and minimized the effect of DSY. Thus, our study showed that DSY potentially exerted anti-EndMT activity through the LASP1/PI3K/AKT pathway, providing a possible new therapeutic intervention for atherosclerosis.

Decoding microRNA drivers in Atherosclerosis

An estimated 97% of the human genome consists of non-protein-coding sequences. As our understanding of genome regulation improves, this has led to the characterization of a diverse array of non-coding RNAs (ncRNA). Among these, micro-RNAs (miRNAs) belong to the short ncRNA class (22–25 nucleotides in length), with approximately 2500 miRNA genes encoded within the human genome. From a therapeutic perspective, there is interest in exploiting miRNA as biomarkers of disease progression and response to treatments, as well as miRNA mimics/repressors as novel medicines. miRNA have emerged as an important class of RNA master regulators with important roles identified in the pathogenesis of atherosclerotic cardiovascular disease. Atherosclerosis is characterized by a chronic inflammatory build-up, driven largely by low-density lipoprotein cholesterol accumulation within the artery wall and vascular injury, including endothelial dysfunction, leukocyte recruitment and vascular remodelling. Conventional therapy focuses on lifestyle interventions, blood pressure-lowering medications, high-intensity statin therapy and antiplatelet agents. However, a significant proportion of patients remain at increased risk of cardiovascular disease. This continued cardiovascular risk is referred to as residual risk. Hence, a new drug class targeting atherosclerosis could synergise with existing therapies to optimise outcomes. Here, we review our current understanding of the role of ncRNA, with a focus on miRNA, in the development and progression of atherosclerosis, highlighting novel biological mechanisms and therapeutic avenues.

The Role of Endothelial-to-Mesenchymal Transition in Cardiovascular Disease

Endothelial-to-mesenchymal transition (EndoMT) is the process of endothelial cells progressively losing endothelial-specific markers and gaining mesenchymal phenotypes. In the normal physiological condition, EndoMT plays a fundamental role in forming the cardiac valves of the developing heart. However, EndoMT contributes to the development of various cardiovascular diseases (CVD), such as atherosclerosis, valve diseases, fibrosis, and pulmonary arterial hypertension (PAH). Therefore, a deeper understanding of the cellular and molecular mechanisms underlying EndoMT in CVD should provide urgently needed insights into reversing this condition. This review summarizes a 30-year span of relevant literature, delineating the EndoMT process in particular, key signaling pathways, and the underlying regulatory networks involved in CVD.

Non-Coding RNAs in the Therapeutic Landscape of Pathological Cardiac Hypertrophy

Cardiovascular diseases are a major health problem, and long-term survival for people diagnosed with heart failure is, still, unrealistic. Pathological cardiac hypertrophy largely contributes to morbidity and mortality, as effective therapeutic approaches are lacking. Non-coding RNAs (ncRNAs) arise as active regulators of the signaling pathways and mechanisms that govern this pathology, and their therapeutic potential has received great attention in the last decades. Preclinical studies in large animal models have been successful in ameliorating cardiac hypertrophy, and an antisense drug for the treatment of heart failure has, already, entered clinical trials. In this review, we provide an overview of the molecular mechanisms underlying cardiac hypertrophy, the involvement of ncRNAs, and the current therapeutic landscape of oligonucleotides targeting these regulators. Strategies to improve the delivery of such therapeutics and overcome the actual challenges are, also, defined and discussed. With the fast advance in the improvement of oligonucleotide drug delivery, the inclusion of ncRNAs-targeting therapies for cardiac hypertrophy seems, increasingly, a closer reality.

A new player in the game: treatment with antagomiR-21a-5p significantly attenuates histological and echocardiographic effects of experimental autoimmune myocarditis

AIMS

Myocarditis is associated with formidable symptoms and increased risk of adverse outcomes. Current approaches mostly rely on symptomatic treatments, warranting novel concepts for clinical practice. The aim of this study was to investigate the microRNA (miRNA) expression profile of Balb/c mice with experimental autoimmune myocarditis (EAM), choose a representative miRNA to antagonize after review of available literature and test its effects on myocardial inflammation in vitro and in vivo.

METHODS AND RESULTS

Phase 1: EAM was induced in 12 male Balb/c mice, 10 animals served as controls. After sacrifice, next-generation sequencing (NGS) of the miRNA expression profile was performed. Based on these results, H9C2 cells and human ventricular cardiac fibroblasts exposed to lipopolysaccharide (LPS) were treated with the selected candidate antagomiR-21a-5p. Phase 2: EAM was induced in 48 animals. Thereof, 24 animals were either treated with antagomiR-21a-5p or negative control oligonucleotide in a nanoparticle formulation. Transthoracic echocardiography (TTE) was performed on Days 0, 7, 14, and 21. Histopathological examination was performed after sacrifice. Phase 1: EAM resulted in a significant up-regulation of 27 miRNAs, including miR-21a-5p (log2FC: 2.23, adj. P = 0.0026). Transfection with antagomiR-21a-5p resulted in a significant reduction of TNFα, IL-6, and collagen I in vitro. Phase 2: Treatment with antagomiR-21a-5p, formulated in polymeric nanoparticles for systemic injection, significantly attenuated myocardial inflammation (P = 0.001) and fibrosis (P = 0.013), as well as myocardial 'hypertrophy' on TTE.

CONCLUSIONS

Silencing of miR-21a-5p results in a significant reduction of the expression of pro-inflammatory cytokines in vitro, as well as a significant attenuation of inflammation, fibrosis and echocardiographic effects of EAM in vivo.

Exosomes in cardiovascular diseases: a blessing or a sin for the mankind

Cardiovascular diseases (CVDs) comprises disorders of blood vessels and heart. Multiple cells in the heart suggests that hetero-cellular communication, which is an important aspect in heart functioning and there is a need to elucidate the way in which this inter-cellular communication occurs. Now a days, exosomal research has gained much attention. Exosomes, nano-shuttles, are EVs with diameters ranging from 40 to 160 nm (average 100 nm), secreted by body cells. These vesicles act as cell-to-cell communicators and are carriers of important biomolecules such as RNAs, miRNAs, Proteins and lipids. Exosomes can change the gene expression of the recipient cells, thereby, changes the cellular characteristics. Exosomes have known to play an essential role in protection as well as progression of various cardiovascular diseases. In the present review, role of exosomes in various CVDs have been discussed.

Signaling Pathways Related to Oxidative Stress in Diabetic Cardiomyopathy

Diabetes is a chronic metabolic disease that is increasing in prevalence and causes many complications. Diabetic cardiomyopathy (DCM) is a complication of diabetes that is associated with high mortality, but it is not well defined. Nevertheless, it is generally accepted that DCM refers to a clinical disease that occurs in patients with diabetes and involves ventricular dysfunction, in the absence of other cardiovascular diseases, such as coronary atherosclerotic heart disease, hypertension, or valvular heart disease. However, it is currently uncertain whether the pathogenesis of DCM is directly attributable to metabolic dysfunction or secondary to diabetic microangiopathy. Oxidative stress (OS) is considered to be a key component of its pathogenesis. The production of reactive oxygen species (ROS) in cardiomyocytes is a vicious circle, resulting in further production of ROS, mitochondrial DNA damage, lipid peroxidation, and the post-translational modification of proteins, as well as inflammation, cardiac hypertrophy and fibrosis, ultimately leading to cell death and cardiac dysfunction. ROS have been shown to affect various signaling pathways involved in the development of DCM. For instance, OS causes metabolic disorders by affecting the regulation of PPARα, AMPK/mTOR, and SIRT3/FOXO3a. Furthermore, OS participates in inflammation mediated by the NF-κB pathway, NLRP3 inflammasome, and the TLR4 pathway. OS also promotes TGF-β-, Rho-ROCK-, and Notch-mediated cardiac remodeling, and is involved in the regulation of calcium homeostasis, which impairs ATP production and causes ROS overproduction. In this review, we summarize the signaling pathways that link OS to DCM, with the intention of identifying appropriate targets and new antioxidant therapies for DCM.

Bone Marrow Lymphoid Niche Adaptation to Mature B Cell Neoplasms

B-cell non-Hodgkin lymphoma (B-NHL) evolution and treatment are complicated by a high prevalence of relapses primarily due to the ability of malignant B cells to interact with tumor-supportive lymph node (LN) and bone marrow (BM) microenvironments. In particular, progressive alterations of BM stromal cells sustain the survival, proliferation, and drug resistance of tumor B cells during diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL). The current review describes how the crosstalk between BM stromal cells and lymphoma tumor cells triggers the establishment of the tumor supportive niche. DLBCL, FL, and CLL display distinct patterns of BM involvement, but in each case tumor-infiltrating stromal cells, corresponding to cancer-associated fibroblasts, exhibit specific phenotypic and functional features promoting the recruitment, adhesion, and survival of tumor cells. Tumor cell-derived extracellular vesicles have been recently proposed as playing a central role in triggering initial induction of tumor-supportive niches, notably within the BM. Finally, the disruption of the BM stroma reprogramming emerges as a promising therapeutic option in B-cell lymphomas. Targeting the crosstalk between BM stromal cells and malignant B cells, either through the inhibition of stroma-derived B-cell growth factors or through the mobilization of clonal B cells outside their supportive BM niche, should in particular be further evaluated as a way to avoid relapses by abrogating resistance niches.

Differentiation of the tumor microenvironment: are CAFs the Organizer?

Cancers contain a suite of genetically stable cells within an extracellular matrix, collectively termed the tumor microenvironment (TME). The TME strongly influences disease outcome for patients. Gleaning clues from the literature, we propose that the TME should be viewed not as disparate populations of cells constituting a pathological lesion, but as a cohesive tissue constituting a novel pathological organ, arising from the coordinated differentiation of its constituent cell types - a process we have termed tumor-associated neodifferentiation (TAND). We also discuss why cancer-associated fibroblasts (CAFs) may assume the role of Organizer of this organ, directing the recruitment and differentiation of cells within the TME. Viewing the microenvironment in this way will reveal new cancer vulnerabilities that may be exploited for therapy.

Cardiorenal Syndrome: New Pathways and Novel Biomarkers

Cardiorenal syndrome (CRS) is a multi-organ disease characterized by the complex interaction between heart and kidney during acute or chronic injury. The pathogenesis of CRS involves metabolic, hemodynamic, neurohormonal, and inflammatory mechanisms, and atherosclerotic degeneration. In the process of better understanding the bi-directional pathophysiological aspects of CRS, the need to find precise and easy-to-use markers has also evolved. Based on the new pathophysiological standpoints and an overall vision of the CRS, the literature on renal, cardiac, metabolic, oxidative, and vascular circulating biomarkers was evaluated. Though the effectiveness of different extensively applied biomarkers remains controversial, evidence for several indicators, particularly when combined, has increased in recent years. From new aspects of classic biomarkers to microRNAs, this review aimed at a 360-degree analysis of the pathways that balance the kidney and the heart physiologies. In this delicate system, different markers and their combination can shed light on the diagnosis, risk, and prognosis of CRS.

MicroRNA targets and biomarker validation for diabetes-associated cardiac fibrosis

Cardiac fibrosis is one of the main characteristics of diabetic cardiomyopathy and manifests excessive accumulation of extracellular matrix proteins in the heart. Several signaling pathways have been proposed for pathogenesis of cardiac fibrosis in the diabetic heart. TGF-β/Smad2/3-dependent or independent pathway is the major signaling molecule core in the pathogenesis of cardiac fibrosis. MicroRNAs (miRNAs, miR) are ~22-nuceotide regulatory RNAs that are involved in gene silencing through the degradation of post-transcriptional mRNA or suppression of the expressed proteins. Hyperglycemia in the diabetic heart regulates expression of some miRNAs. Target molecules of miRNAs can be identified through biocomputational database initial screening and dual luciferase assay validation. miR-21, miR-150-5p, miR-155, miR-216a-3p, miR-221-3p, miR-223, and miR-451 were up-regulated in the diabetic heart and promoted cardiac fibrosis through targeting signaling pathways in cardiac fibroblasts, endothelial cells, and cardiac myocytes. miR-15a/-15b, miR-18a-5p, miR-20a-5p, miR-26b-5p, miR-29, miR-133a, miR-141, miR-146, miR-200b, miR-203, miR-222, and miR-551b-5p were down-regulated in the diabetic heart and exhibited anti-fibrosis when they were overexpressed. miRNAs are stable molecules and may reflect the pathological changes of organs. Some miRNAs have been detected in the plasma or serum in patients with diabetes mellitus or heart failure. Exploration of targets and biomarkers of miRNA may provide additional information on pathogenesis and diagnosis of cardiac fibrosis and novel targets to tackle diabetic cardiomyopathy.

Downregulation of microRNA-21 contributes to decreased collagen expression in venous malformations via transforming growth factor-β/Smad3/microRNA-21 signaling feedback loop

OBJECTIVE

Venous malformations (VMs) are the most frequent vascular malformations and are characterized by dilated and tortuous veins with a dysregulated vascular extracellular matrix. The purpose of the present study was to investigate the potential involvement of microRNA-21 (miR-21), a multifunctional microRNA tightly associated with extracellular matrix regulation, in the pathogenesis of VMs.

METHODS

The expression of miR-21, collagen I, III, and IV, transforming growth factor-β (TGF-β), and Smad3 (mothers against decapentaplegic homolog 3) was evaluated in VMs and normal skin tissue using in situ hybridization, immunohistochemistry, Masson trichrome staining, and real-time polymerase chain reaction. Human umbilical vein endothelial cells (HUVECs) were used to explore the underlying mechanisms.

RESULTS

miR-21 expression was markedly decreased in the VM specimens compared with normal skin, in parallel with downregulation of collagen I, III, and IV and the TGF-β/Smad3 pathway in VMs. Moreover, our data demonstrated that miR-21 positively regulated the expression of collagens in HUVECs and showed a positive association with the TGF-β/Smad3 pathway in the VM tissues. In addition, miR-21 was found to mediate TGF-β-induced upregulation of collagens in HUVECs. Our data have indicated that miR-21 and the TGF-β/Smad3 pathway could form a positive feedback loop to synergistically regulate endothelial collagen synthesis. In addition, TGF-β/Smad3/miR-21 feedback loop signaling was upregulated in bleomycin-treated HUVECs and VM specimens, which was accompanied by increased collagen deposition.

CONCLUSIONS

To the best of our knowledge, the present study has, for the first time, revealed downregulation of miR-21 in VMs, which might contribute to decreased collagen expression via the TGF-β/Smad3/miR-21 signaling feedback loop. These findings provide new information on the pathogenesis of VMs and might facilitate the development of new therapies for VMs.

Endothelial-Mesenchymal Transition in Cardiovascular Disease

Endothelial-to-mesenchymal transition is a dynamic process in which endothelial cells suppress constituent endothelial properties and take on mesenchymal cell behaviors. To begin the process, endothelial cells loosen their cell-cell junctions, degrade the basement membrane, and migrate out into the perivascular surroundings. These initial endothelial behaviors reflect a transient modulation of cellular phenotype, that is, a phenotypic modulation, that is sometimes referred to as partial endothelial-to-mesenchymal transition. Loosening of endothelial junctions and migration are also seen in inflammatory and angiogenic settings such that endothelial cells initiating endothelial-to-mesenchymal transition have overlapping behaviors and gene expression with endothelial cells responding to inflammatory signals or sprouting to form new blood vessels. Reduced endothelial junctions increase permeability, which facilitates leukocyte trafficking, whereas endothelial migration precedes angiogenic sprouting and neovascularization; both endothelial barriers and quiescence are restored as inflammatory and angiogenic stimuli subside. Complete endothelial-to-mesenchymal transition proceeds beyond phenotypic modulation such that mesenchymal characteristics become prominent and endothelial functions diminish. In proadaptive, regenerative settings the new mesenchymal cells produce extracellular matrix and contribute to tissue integrity whereas in maladaptive, pathologic settings the new mesenchymal cells become fibrotic, overproducing matrix to cause tissue stiffness, which eventually impacts function. Here we will review what is known about how TGF (transforming growth factor) β influences this continuum from junctional loosening to cellular migration and its relevance to cardiovascular diseases.

MiR-126-3p Is Dynamically Regulated in Endothelial-to-Mesenchymal Transition during Fibrosis

In fibrotic diseases, myofibroblasts derive from a range of cell types including endothelial-to-mesenchymal transition (EndMT). Increasing evidence suggests that miRNAs are key regulators in biological processes but their profile is relatively understudied in EndMT. In human umbilical vein endothelial cells (HUVEC), EndMT was induced by treatment with TGFβ2 and IL1β. A significant decrease in endothelial markers such as VE-cadherin, CD31 and an increase in mesenchymal markers such as fibronectin were observed. In parallel, miRNA profiling showed that miR-126-3p was down-regulated in HUVECs undergoing EndMT and over-expression of miR-126-3p prevented EndMT, maintaining CD31 and repressing fibronectin expression. EndMT was investigated using lineage tracing with transgenic Cdh5-Cre-ERT2; Rosa26R-stop-YFP mice in two established models of fibrosis: cardiac ischaemic injury and kidney ureteric occlusion. In both cardiac and kidney fibrosis, lineage tracing showed a significant subpopulation of endothelial-derived cells expressed mesenchymal markers, indicating they had undergone EndMT. In addition, miR-126-3p was restricted to endothelial cells and down-regulated in murine fibrotic kidney and heart tissue. These findings were confirmed in patient kidney biopsies. MiR-126-3p expression is restricted to endothelial cells and is down-regulated during EndMT. Over-expression of miR-126-3p reduces EndMT, therefore, it could be considered for miRNA-based therapeutics in fibrotic organs.

Exercising immune cells: The immunomodulatory role of exercise on atrial fibrillation

Exercise training is generally beneficial for cardiovascular health, improving stroke volume, cardiac output, and aerobic capacity. Despite these benefits, some evidence indicates that endurance training may increase the risk of atrial fibrillation (AF), particularly in highly trained individuals. Among multiple mechanisms, autonomic tone changes and atrial remodeling have been proposed as main contributors for exercise-induced AF. However, the contribution of local and systemic immunity is poorly understood in the development of atrial arrhythmogenic substrates. Here we aim to update the field of immunomodulation in the context of exercise and AF by compiling and reconciling the most recent evidence from preclinical and human studies and rationalize the applicability of "lone" AF terminology in athletes.

The effect of long-term left ventricular assist device support on flow-sensitive plasma microRNA levels

BACKGROUND

Implantation of current generation left ventricular assist devices (LVADs) in the treatment of end-stage heart failure (HF), not only improves HF symptoms and end-organ perfusion, but also leads to cellular and molecular responses, presumably in response to the continuous flow generated by these devices. MicroRNAs (miRNAs) are important post-transcriptional regulators of gene expression in multiple biological processes, including the pathogenesis of HF. In our study, we examined the influence of long-term LVAD support on changes in flow-sensitive miRNAs in plasma.

MATERIALS AND METHODS

Blood samples from patients with end-stage heart failure (N = 33; age = 55.7 ± 11.6 years) were collected before LVAD implantation and 3, 6, 9, and 12 months after implantation. Plasma levels of the flow-sensitive miRNAs; miR-10a, miR-10b, miR-146a, miR-146b, miR-663a, miR-663b, miR-21, miR-155, and miR-126 were measured using quantitative PCR.

RESULTS

Increasing quantities of miR-126 (P < 0.03) and miR-146a (P < 0.02) was observed at each follow-up visit after LVAD implantation. A positive association between miR-155 and Belcaro score (P < 0.04) and an inverse correlation between miR-126 and endothelial function, measured as the reactive hyperemia index (P < 0.05), was observed.

CONCLUSIONS

Our observations suggest that after LVAD implantation, low pulsatile flow up-regulates plasma levels of circulating flow-sensitive miRNAs, contributing to endothelial dysfunction and vascular remodeling.

Noncoding RNAs as Promising Diagnostic Biomarkers and Therapeutic Targets in Intestinal Fibrosis of Crohn's Disease: The Path From Bench to Bedside

Fibrosis is a major pathway to organ injury and failure, accounting for more than one-third of deaths worldwide. Intestinal fibrosis causes irreversible and serious clinical complications, such as strictures and obstruction, secondary to a complex pathogenesis. Under the stimulation of profibrotic soluble factors, excessive activation of mesenchymal cells causes extracellular matrix deposition via canonical transforming growth factor-β/Smads signaling or other pathways (eg, epithelial-to-mesenchymal transition and endothelial-to-mesenchymal transition) in intestinal fibrogenesis. In recent studies, the importance of noncoding RNAs (ncRNAs) stands out in fibrotic diseases in that ncRNAs exhibit a remarkable variety of biological functions in modulating the aforementioned fibrogenic responses. In this review, we summarize the role of ncRNAs, including the emerging long ncRNAs and circular RNAs, in intestinal fibrogenesis. Notably, the translational potential of ncRNAs as diagnostic biomarkers and therapeutic targets in the management of intestinal fibrosis is discussed based on clinical trials from fibrotic diseases in other organs. The main points of this review include the following: • Characteristics of ncRNAs and mechanisms of intestinal fibrogenesis • Wide participation of ncRNAs (especially the emerging long ncRNAs and circular RNAs) in intestinal fibrosis, including transforming growth factor-β signaling, epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition, and extracellular matrix remodeling • Translational potential of ncRNAs in the diagnosis and treatment of intestinal fibrosis based on clinical trials from fibrotic diseases in other organs.

Leveraging clinical epigenetics in heart failure with preserved ejection fraction: a call for individualized therapies

Described as the 'single largest unmet need in cardiovascular medicine', heart failure with preserved ejection fraction (HFpEF) remains an untreatable disease currently representing 65% of new heart failure diagnoses. HFpEF is more frequent among women and associates with a poor prognosis and unsustainable healthcare costs. Moreover, the variability in HFpEF phenotypes amplifies complexity and difficulties in the approach. In this perspective, unveiling novel molecular targets is imperative. Epigenetic modifications-defined as changes of DNA, histones, and non-coding RNAs (ncRNAs)-represent a molecular framework through which the environment modulates gene expression. Epigenetic signals acquired over the lifetime lead to chromatin remodelling and affect transcriptional programmes underlying oxidative stress, inflammation, dysmetabolism, and maladaptive left ventricular remodelling, all conditions predisposing to HFpEF. The strong involvement of epigenetic signalling in this setting makes the epigenetic information relevant for diagnostic and therapeutic purposes in patients with HFpEF. The recent advances in high-throughput sequencing, computational epigenetics, and machine learning have enabled the identification of reliable epigenetic biomarkers in cardiovascular patients. Contrary to genetic tools, epigenetic biomarkers mirror the contribution of environmental cues and lifestyle changes and their reversible nature offers a promising opportunity to monitor disease states. The growing understanding of chromatin and ncRNAs biology has led to the development of several Food and Drug Administration approved 'epidrugs' (chromatin modifiers, mimics, anti-miRs) able to prevent transcriptional alterations underpinning left ventricular remodelling and HFpEF. In the present review, we discuss the importance of clinical epigenetics as a new tool to be employed for a personalized management of HFpEF.

EndMT Regulation by Small RNAs in Diabetes-Associated Fibrotic Conditions: Potential Link With Oxidative Stress

Diabetes-associated complications, such as retinopathy, nephropathy, cardiomyopathy, and atherosclerosis, the main consequences of long-term hyperglycemia, often lead to organ dysfunction, disability, and increased mortality. A common denominator of these complications is the myofibroblast-driven excessive deposition of extracellular matrix proteins. Although fibroblast appears to be the primary source of myofibroblasts, other cells, including endothelial cells, can generate myofibroblasts through a process known as endothelial to mesenchymal transition (EndMT). During EndMT, endothelial cells lose their typical phenotype to acquire mesenchymal features, characterized by the development of invasive and migratory abilities as well as the expression of typical mesenchymal products such as α-smooth muscle actin and type I collagen. EndMT is involved in many chronic and fibrotic diseases and appears to be regulated by complex molecular mechanisms and different signaling pathways. Recent evidence suggests that small RNAs, in particular microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), are crucial mediators of EndMT. Furthermore, EndMT and miRNAs are both affected by oxidative stress, another key player in the pathophysiology of diabetic fibrotic complications. In this review, we provide an overview of the primary redox signals underpinning the diabetic-associated fibrotic process. Then, we discuss the current knowledge on the role of small RNAs in the regulation of EndMT in diabetic retinopathy, nephropathy, cardiomyopathy, and atherosclerosis and highlight potential links between oxidative stress and the dyad small RNAs-EndMT in driving these pathological states.

The Impact of microRNAs in Renin-Angiotensin-System-Induced Cardiac Remodelling

Current knowledge on the renin-angiotensin system (RAS) indicates its central role in the pathogenesis of cardiovascular remodelling via both hemodynamic alterations and direct growth and the proliferation effects of angiotensin II or aldosterone resulting in the hypertrophy of cardiomyocytes, the proliferation of fibroblasts, and inflammatory immune cell activation. The noncoding regulatory microRNAs has recently emerged as a completely novel approach to the study of the RAS. A growing number of microRNAs serve as mediators and/or regulators of RAS-induced cardiac remodelling by directly targeting RAS enzymes, receptors, signalling molecules, or inhibitors of signalling pathways. Specifically, microRNAs that directly modulate pro-hypertrophic, pro-fibrotic and pro-inflammatory signalling initiated by angiotensin II receptor type 1 (AT1R) stimulation are of particular relevance in mediating the cardiovascular effects of the RAS. The aim of this review is to summarize the current knowledge in the field that is still in the early stage of preclinical investigation with occasionally conflicting reports. Understanding the big picture of microRNAs not only aids in the improved understanding of cardiac response to injury but also leads to better therapeutic strategies utilizing microRNAs as biomarkers, therapeutic agents and pharmacological targets.