Circulating miR-let7a levels predict future diagnosis of chronic thromboembolic pulmonary hypertension.

Distinct patterns of circulating microRNAs (miRNAs) were found to be involved in misguided thrombus resolution. Thus, we aimed to investigate dysregulated miRNA signatures during the acute phase of pulmonary embolism (PE) and test their diagnostic and predictive value for future diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH). Microarray screening and subsequent validation in a large patient cohort (n = 177) identified three dysregulated miRNAs as potential biomarkers: circulating miR-29a and miR-720 were significantly upregulated and miR-let7a was significantly downregulated in plasma of patients with PE. In a second validation study equal expression patterns for miR-29a and miR-let7a regarding an acute event of recurrent venous thromboembolism (VTE) or deaths were found. MiR-let7a concentrations significantly correlated with echocardiographic and laboratory parameters indicating right ventricular (RV) dysfunction. Additionally, circulating miR-let7a levels were associated with diagnosis of CTEPH during follow-up. Regarding CTEPH diagnosis, ROC analysis illustrated an AUC of 0.767 (95% CI 0.54-0.99) for miR-let7a. Using logistic regression analysis, a calculated patient-cohort optimized miR-let7a cut-off value derived from ROC analysis of ≥ 11.92 was associated with a 12.8-fold increased risk for CTEPH. Therefore, miR-let7a might serve as a novel biomarker to identify patients with haemodynamic impairment and as a novel predictor for patients at risk for CTEPH.

Dimensión subjetiva de los procesos de trabajo en profesionales de salud en contexto de pandemia: un estudio exploratorio a partir del análisis de dispositivos de Apoyo a los Equipos de Salud en un municipio del Área Metropolitana de Buenos Aires (AMBA)

Resumen: Objetivo: caracterizar la dimensión subjetiva de los procesos de trabajo en el primer nivel de atención en contexto de pandemia, a través de la descripción y análisis de los discursos de los y las trabajadores/as producidos en el marco del dispositivo de Apoyo a los Equipos de Salud implementado en un municipio del área metropolitana de Buenos Aires. Metodología: investigación cualitativa, exploratoria y descriptiva. Estudio de caso único centrado en observación participante en 10 reuniones en centros de salud del Municipio de Tigre, durante los meses de abril y mayo de 2020. La sistematización del material se realizó siguiendo técnicas de análisis de contenido y generación de categorías. Resultados: el análisis permitió identificar cinco categorías emergentes: a) cambios en los escenarios de trabajo, b) emociones y actitudes frente a la tarea, c) vínculos al interior de los equipos, d) vínculos con las autoridades y e) vínculos con la comunidad. Discusión: la dimensión subjetiva contenida en las vivencias relatadas está caracterizada por sensaciones de incertidumbre, miedos, tensiones en la relación entre compañeros/as, con las instancias jerárquicas y con la población asistida, pero también por búsquedas activas de alternativas, apoyo entre compañeros/as, participación, motivación en los sentidos del trabajo, cuidados mutuos y acercamiento a la comunidad. De este modo se hacen visibles aspectos que preexistían a la situación de pandemia y aspectos que el contexto introduce. Finalmente, se arriba a algunas reflexiones sobre las implicancias de la inclusión de este dispositivo en el proceso de trabajo de equipos de salud durante la pandemia.

Abstract: Objective: characterize the subjective dimension of the work processes at the first level of care in the context of a pandemic, through the description and analysis of the speeches of the workers produced within the framework of the Health Team Support device implemented in a municipality in the metropolitan area of Buenos Aires. Methodology: qualitative, exploratory and descriptive research. Single case study focused on participant observation in 10 meetings in health centers of the Municipality of Tigre, during the months of April and May 2020. The systematization of the material was carried out following techniques of content analysis and category generation. Results: the analysis identified five emerging categories: a) changes in work settings, b) emotions and attitudes towards the task, c) ties within teams, d) ties with authorities, and e) ties with the community. Discussion: the subjective dimension contained in the experiences reported are characterized by feelings of uncertainty, fears, tensions in the relationship between colleagues, with hierarchical instances and with the assisted population, but also by active searches for alternatives, support among colleagues, participation, motivation in the sense of work, mutual care and approach to the community. In this way, aspects that pre-existed the pandemic situation and aspects that the context introduce are made visible. Finally, we come up with some reflections on the implications of the inclusion of this device in the work process of health teams during the pandemic.

Resumo: Objetivo: caracterizar a dimensão subjetiva dos processos de trabalho em primeiro nível de atenção em contexto de pandemia, por meio da descrição e análise das falas dos trabalhadores produzidos no âmbito do dispositivo de Apoio à Equipe de Saúde implantado em município da região metropolitana de Buenos Aires. Metodologia: pesquisa qualitativa, exploratória e descritiva. Estudo de caso único com foco na observação participante em 10 encontros em centros de saúde do Município de Tigre, durante os meses de abril e maio de 2020. A sistematização do material foi realizada seguindo técnicas de análise de conteúdo e geração de categorias. Resultados: a análise identificou cinco categorias emergentes: a) mudanças nos ambientes de trabalho, b) emoções e atitudes em relação à tarefa, c) vínculos dentro das equipes, d) vínculos com autoridades e e) vínculos com a comunidade. Discussão: a dimensão subjetiva contida nas vivências relatadas é caracterizada por sentimentos de incerteza, medos, tensões na relação entre colegas, com instâncias hierárquicas e com a população assistida, mas também por buscas ativas de alternativas, apoio entre colegas, participação, motivação no sentido de trabalho, cuidado mútuo e aproximação com a comunidade. Desta forma, tornam-se visíveis os aspectos prévios à situação pandémica e os que o contexto introduz. Por fim, são feitas algumas reflexões sobre as implicações da inclusão desse dispositivo no processo de trabalho das equipes de saúde durante a pandemia.

Abordajes comunitarios en salud mental en el primer nivel de atención: conceptos y prácticas desde una perspectiva integral / Community approaches in mental health at the first Level of care: concepts and practices from an integral Perspective

El objetivo de este trabajo fue realizar una aproximación conceptual y análisis de prácticas que permitan problematizar la inclusión de estrategias comunitarias en abordajes integrales de salud mental. Desde una perspectiva cualitativa, este escrito es producto de un proceso de articulación conceptual y sistematización derivado de un análisis reflexivo sobre prácticas de salud mental desarrolladas en el primer nivel de atención en la ciudad y provincia de Buenos Aires desde el año 2010. Se reconoce la fragilización de redes comunitarias como una problemática colectiva en salud mental, y se propone a la promoción en salud mental como estrategia central que permite, desde una perceptiva no normativa e integral, el desarrollo de acciones participativas y el fortalecimiento de lazos comunitarios solidarios como recursos colectivos para el cuidado de la salud mental. Se abordan ejes problemáticos relevados en la implementación de dichas prácticas y su relación con una vigente tensión entre los modelos biomédico e integral de atención. Se articulan reflexiones relacionadas a la pandemia por COVID-19, evidenciando una necesidad actual de profundizar el desarrollo de estrategias comunitarias en salud mental.

The objective of this work was to carry out a conceptual approach and analysis of practices that allow problematizing the inclusion of community strategies in comprehensive mental health approaches. From a qualitative perspective, this paper is the result of a process of conceptual articulation and systematization derived from a reflexive analysis of mental health practices developed in the first level of care in the City and Province of Buenos Aires since 2010. The fragilization of community networks is recognized as a collective mental health problem, and mental health promotion is proposed as a central strategy that allows, from a non-normative and comprehensive perspective, the development of participatory actions and the strengthening of supportive community bonds, as collective resources for mental health care. It addresses problematic axes revealed in the implementation of such practices and their relationship with a current tension between the biomedical and integral models of care. Reflections related to the COVID-19 pandemic are articulated, evidencing a current need to deepen the development of community strategies in mental health.

Apoyo Equipos de Salud en Contexto de Pandemia Covid-19 / Support Health Teams in the Context of the Covid-19 Pandemic

INTRODUCCIÓN El contexto de pandemia ha impuesto a los sistemas de salud una exigencia de trabajo inédita. Desde el punto de vista de la salud mental, los equipos de salud se encuentran expuestos a situaciones de tensión que pueden generar sufrimiento psíquico. Por ello el trabajo de apoyo a los equipos es considerado una acción prioritaria en este contexto. OBJETIVO Caracterizar la dimensión subjetiva de los procesos de trabajo en el primer nivel de atención en contexto de pandemia, a través de la descripción y análisis de los discursos de los y las trabajadores/as producidos en el marco del Dispositivo de Apoyo a los Equipos de Salud implementado en un municipio del área metropolitana de Buenos Aires. METODOLOGÍA Investigación cualitativa, exploratoria y descriptiva. Estudio de caso único centrado en observación participante en reuniones de equipo y entrevistas realizadas en centros de salud del Municipio de Tigre. La sistematización del material se realizó siguiendo técnicas de análisis de contenido y generación de categorías. RESULTADOS El análisis permitió identificar cinco categorías emergentes 1. Cambios en los escenarios de trabajo, 2. Emociones y actitudes frente a la tarea, 3. Vínculos al interior de los equipos, 4. Vínculos con las autoridades y 5. Vínculos con la comunidad. DISCUSIÓN La dimensión subjetiva contenida en las vivencias relatadas está caracterizada por sensaciones de incertidumbre, miedos, tensiones en la relación entre compañeros/as, con las instancias jerárquicas y con la población asistida, pero también por búsquedas activas de alternativas, apoyo entre compañeros/as, participación, 4 motivación en los sentidos del trabajo, cuidados mutuos y acercamiento a la comunidad. De este modo se hacen visibles aspectos que preexistían a la situación de pandemia y aspectos que el contexto introduce. Se evidencia que ha sido muy positiva la apertura de espacios de conversación coordinados por psicólogos/as como práctica de cuidado en salud mental.

Elevated levels of miR-181c and miR-633 in the CSF of patients with MS: A validation study.

OBJECTIVE: To validate a previously discovered microRNA (miRNA) panel in the CSF of patients with MS, we now tested the diagnostic value of CSF-derived candidate miRNAs in a case-control study in a larger MS cohort. METHODS: The levels of miR-181c, miR-633, and miR-922 were analyzed in the CSF of 218 patients with MS and 211 patients with other neurologic diseases (OND) by real-time quantitative reverse transcriptase PCR. RESULTS: CSF levels of both miR-181c (p < 0.001 and miR-633 p < 0.001) were higher in patients with MS patients compared with patients with OND. Both miR-181c (area under the curve [AUC] 0.75, 95% CI 0.70-0.80, p < 0.001) and miR-633 (AUC 0.75, 95% CI 0.68-0.83, p < 0.001) differentiated MS from OND. Combining both miRNAs yielded a sensitivity of 62% and specificity of 89% to differentiate MS from OND. miR-922 was not confirmed to be differentially expressed in this validation cohort. CONCLUSIONS: The results of this so far largest study on CSF-based miRNAs confirm the diagnostic value of miR-181c and miR-633 for MS. The present study may help to extend the diagnostic tools for patients with suspected MS and may add further knowledge to the pathology of the disease. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that CSF-derived miR-181c and miR-633 distinguish patients with MS from patients with OND.

Long Noncoding RNA-Enriched Vesicles Secreted by Hypoxic Cardiomyocytes Drive Cardiac Fibrosis.

Long non-coding RNAs (lncRNAs) have potential as novel therapeutic targets in cardiovascular diseases, but detailed information about the intercellular lncRNA shuttling mechanisms in the heart is lacking. Here, we report an important novel crosstalk between cardiomyocytes and fibroblasts mediated by the transfer of lncRNA-enriched extracellular vesicles (EVs) in the context of cardiac ischemia. lncRNA profiling identified two hypoxia-sensitive lncRNAs: ENSMUST00000122745 was predominantly found in small EVs, whereas lncRNA Neat1 was enriched in large EVs in vitro and in vivo. Vesicles were taken up by fibroblasts, triggering expression of profibrotic genes. In addition, lncRNA Neat1 was transcriptionally regulated by P53 under basal conditions and by HIF2A during hypoxia. The function of Neat1 was further elucidated in vitro and in vivo. Silencing of Neat1 in vitro revealed that Neat1 was indispensable for fibroblast and cardiomyocyte survival and affected fibroblast functions (reduced migration capacity, stalled cell cycle, and decreased expression of fibrotic genes). Of translational importance, genetic loss of Neat1 in vivo resulted in an impaired heart function after myocardial infarction highlighting its translational relevance.

Attenuated palmitoylation of serotonin receptor 5-HT1A affects receptor function and contributes to depression-like behaviors.

The serotonergic system and in particular serotonin 1A receptor (5-HT1AR) are implicated in major depressive disorder (MDD). Here we demonstrated that 5-HT1AR is palmitoylated in human and rodent brains, and identified ZDHHC21 as a major palmitoyl acyltransferase, whose depletion reduced palmitoylation and consequently signaling functions of 5-HT1AR. Two rodent models for depression-like behavior show reduced brain ZDHHC21 expression and attenuated 5-HT1AR palmitoylation. Moreover, selective knock-down of ZDHHC21 in the murine forebrain induced depression-like behavior. We also identified the microRNA miR-30e as a negative regulator of Zdhhc21 expression. Through analysis of the post-mortem brain samples in individuals with MDD that died by suicide we find that miR-30e expression is increased, while ZDHHC21 expression, as well as palmitoylation of 5-HT1AR, are reduced within the prefrontal cortex. Our study suggests that downregulation of 5-HT1AR palmitoylation is a mechanism involved in depression, making the restoration of 5-HT1AR palmitoylation a promising clinical strategy for the treatment of MDD.

Analizando prácticas participativas en salud: La Semana de Las Crianzas en Villa Soldati / Analyzing participatory practices in health: The Rearing Week in Villa Soldati

RESUMEN Este trabajo describe y analiza una experiencia participativa llevada adelante por un Centro de Salud ubicado en una zona marginal urbana de la Ciudad de Buenos Aires. Dicha experiencia condensa en una semana la realización de gran cantidad de actividades creativas de prevención y promoción de salud, con una planificación conjunta entre profesionales, organizaciones y vecinos del barrio. Se analizan los principales procesos participativos implicados desde la perspectiva de la Atención Primaria de la Salud Integral. Se concluye que el trabajo creativo colectivo resultante posee una gran potencia en la promoción de salud integral en el barrio, como producción de subjetividad alternativa al modelo biomédico de atención.

ABSTRACT The purpose of this paper is to describe and analyze a participative experience conducted by a Community Health Center in a marginal zone of the City of Buenos Aires. Such experience condenses in a week the realization of a large number of prevention and promotion creative activities, with a joint planning among professionals, organizations, and neighbors. Main participatory processes included in the experience are analyzed from the Integral Primary Health Care perspective. It is concluded that the resulting collective creative work has a great power in the promotion of integral health in the neighborhood, as a production of subjectivity alternative to the biomedical care model.

Antagonism of profibrotic microRNA-21 improves outcome of murine chronic renal allograft dysfunction.

Chronic renal allograft dysfunction (CAD) is a major limiting factor of long-term graft survival. It is characterized by interstitial fibrosis and tubular atrophy. The underlying pathomechanisms are incompletely understood. MicroRNAs are powerful regulators of gene expression and may have an impact on various diseases by direct mRNA decay or translational inhibition. A murine model of allogenic kidney transplantation was used resulting in CAD at 6 weeks after kidney transplantation. We identified fibrosis-associated miR-21a-5p by whole miRNAome expression analysis to be among the most highly upregulated miRNAs. In vitro in renal fibroblasts, miR-21a-5p was transcriptionally activated by interleukin 6-induced signal transducer and activator of transcription 3. Co-culture of LPS-activated macrophages with renal fibroblasts increased expression levels of miR-21a-5p and markers of fibrosis and inflammation. In addition, mature miR-21a-5p was secreted by macrophages in small vesicles, which were internalized by renal fibroblasts, thereby promoting profibrotic and proinflammatory effects. Notch2 receptor was identified as a potential target of miR-21a-5p and validated by luciferase gene reporter assays. Therapeutic silencing of miR-21a-5p in mice after allogenic kidney transplantation resulted in an amelioration of CAD, as indicated by a reduction in fibrosis development, inflammatory cell influx, tissue injury and BANFF lesion scoring. In a life-supporting model, miR-21a-5p antagonism had beneficial effects on kidney function. miR-21a-5p silencing may therefore be a viable therapeutic option in the treatment of patients following kidney transplantation to halt the development of CAD.

Therapeutic miR-21 Silencing Ameliorates Diabetic Kidney Disease in Mice.

Diabetic nephropathy is the main cause of end-stage renal disease. MicroRNAs are powerful regulators of the genome, and global expression profiling revealed miR-21 to be among the most highly regulated microRNAs in kidneys of mice with diabetic nephropathy. In kidney biopsies of diabetic patients, miR-21 correlated with tubulointerstitial injury. In situ PCR analysis showed a specific enrichment of miR-21 in glomerular cells. We identified cell division cycle 25a (Cdc25a) and cyclin-dependent kinase 6 (Cdk6) as novel miR-21 targets in mesangial cells. miR-21-mediated repression of Cdc25a and Cdk6 resulted in impaired cell cycle progression and subsequent mesangial cell hypertrophy. miR-21 increased podocyte motility by regulating phosphatase and tensin homolog (Pten). miR-21 antagonism in vitro and in vivo in streptozotocin-induced diabetic mice decreased mesangial expansion, interstitial fibrosis, macrophage infiltration, podocyte loss, albuminuria, and fibrotic- and inflammatory gene expression. In conclusion, miR-21 antagonism rescued various functional and structural parameters in mice with diabetic nephropathy and, thus, might be a viable option in the treatment of patients with diabetic kidney disease.

Cuando la alegría entra al centro de salud: una experiencia de promoción de salud en Buenos Aires, Argentína / When joy enters into the health center: an experience of health promotion in Buenos Aires, Argentina / Quando a alegria entra no centro de saúde: uma experiência de promoção da saúde em Buenos Aires, Argentina

Como parte de una investigación posdoctoral, el presente trabajo describe y analiza una experiencia de promoción y educación para la salud integral desarrollada por un Centro de Salud y Acción Comunitaria en una zona marginal urbana del sur de la Ciudad de Buenos Aires. Se trata de un estudio exploratorio-descriptivo que utiliza técnicas cualitativas para el trabajo de campo y análisis del material. En articulación con las dimensiones de la APS integral, se describe y analiza un dispositivo vincular, centrado en la interdisciplina y la articulación intersectorial como elementos clave de la organización de los cuidados en salud, con la inclusión de la dimensión intercultural y la participación comunitaria. Se incorporan actividades de promoción de salud integral centradas en el arte, creatividad y juego, constituyéndose en una experiencia resistencial al modelo biomédico de atención, con fuerte impacto subjetivo en los profesionales y la comunidad participante.

As part of a postdoctoral research, this paper describes and analyzes an experience of promotion and education for comprehensive health, carried out by a Community Health Center in a slum of the City of Buenos Aires. This is an exploratory and descriptive study based on qualitative research methodologies in the fieldwork and also to examine the results. A linkage artifact is described and analyzed in the perspective of the dimensions of comprehensive PHC, focusing on the interdisciplinary and intersectoral articulation as key elements of the organization of health care, with the inclusion of the intercultural dimension and community participation. This experience incorporates health promotion activities focused on art, creativity and games, becoming an experience of resistance to the biomedical model of services, with a strong subjective impact on the professionals and the participant community.

Como parte da pesquisa de pós-doutorado, o trabalho descreve e analisa uma experiência de promoção e educação para a saúde integral, desenvolvida por um Centro de Saúde e Ação Comunitária em uma zona marginal urbana do sul da Cidade de Buenos Aires. Trata-se de um estudo exploratório-descritivo, que utiliza técnicas qualitativas para o trabalho de campo e análise do material. Articulado com as dimensões da APS integral, descreve-se e se analisa um dispositivo vincular, centralizado na interdisciplina e na articulação intersetorial como elementos-chave da organização dos cuidados com a saúde, com a inclusão da dimensão intercultural e a participação comunitária. Incorporam-se atividades de promoção de saúde integral com o foco na arte, na criatividade e no jogo, constituindo uma experiência resistencial ao modelo biomédico de atenção, com forte impacto subjetivo nos profissionais e na comunidade participante.

Intercellular communication lessons in heart failure.

Cell-cell or inter-organ communication allows the exchange of information and messages, which is essential for the coordination of cell/organ functions and the maintenance of homeostasis. It has become evident that dynamic interactions of different cell types play a major role in the heart, in particular during the progression of heart failure, a leading cause of mortality worldwide. Heart failure is associated with compensatory structural and functional changes mostly in cardiomyocytes and cardiac fibroblasts, which finally lead to cardiomyocyte hypertrophy and fibrosis. Intercellular communication within the heart is mediated mostly via direct cell-cell interaction or the release of paracrine signalling mediators such as cytokines and chemokines. However, recent studies have focused on the exchange of genetic information via the packaging into vesicles as well as the crosstalk of lipids and other paracrine molecules within the heart and distant organs, such as kidney and adipose tissue, which might all contribute to the pathogenesis of heart failure. In this review, we discuss emerging communication networks and respective underlying mechanisms which could be involved in cardiovascular disease conditions and further emphasize promising therapeutic targets for drug development.

Osteopontin is indispensible for AP1-mediated angiotensin II-related miR-21 transcription during cardiac fibrosis.

AIMS: Osteopontin (OPN) is a multifunctional cytokine critically involved in cardiac fibrosis. However, the underlying mechanisms are unresolved. Non-coding RNAs are powerful regulators of gene expression and thus might mediate this process. METHODS AND RESULTS: OPN and miR-21 were significantly increased in cardiac biopsies of patients with myocardial fibrosis. Ang II infusion via osmotic minipumps led to specific miRNA regulations with miR-21 being strongly induced in wild-type (WT) but not OPN knockout (KO) mice. This was associated with enhanced cardiac collagen content, myofibroblast activation, ERK-MAP kinase as well as AKT signalling pathway activation and a reduced expression of Phosphatase and Tensin Homologue (PTEN) as well as SMAD7 in WT but not OPN KO mice. In contrast, cardiotropic AAV9-mediated overexpression of OPN in vivo further enhanced cardiac fibrosis. In vitro, Ang II induced expression of miR-21 in WT cardiac fibroblasts, while miR-21 levels were unchanged in OPN KO fibroblasts. As pri-miR-21 was also increased by Ang II, we studied potential involved upstream regulators; Electrophoretic Mobility Shift and Chromatin Immunoprecipitation analyses confirmed activation of the miR-21 upstream-transcription factor AP-1 by Ang II. Recombinant OPN directly activated miR-21, enhanced fibrosis, and activated the phosphoinositide 3-kinase pathway. Locked nucleic acid-mediated miR-21 silencing ameliorated cardiac fibrosis development in vivo. CONCLUSION: In cardiac fibrosis related to Ang II, miR-21 is transcriptionally activated and targets PTEN/SMAD7 resulting in increased fibroblast survival. OPN KO animals are protected from miR-21 increase and fibrosis development due to impaired AP-1 activation and fibroblast activation.

Impairment of Wound Healing in Patients With Type 2 Diabetes Mellitus Influences Circulating MicroRNA Patterns via Inflammatory Cytokines.

OBJECTIVE: MicroRNAs (miRNA/miR) are stably present in body fluids and are increasingly explored as disease biomarkers. Here, we investigated influence of impaired wound healing on the plasma miRNA signature and their functional importance in patients with type 2 diabetes mellitus. APPROACH AND RESULTS: miRNA array profiling identified 41 miRNAs significantly deregulated in diabetic controls when compared with patients with diabetes mellitus-associated peripheral arterial disease and chronic wounds. Quantitative real-time polymerase chain reaction validation confirmed decrease in circulating miR-191 and miR-200b levels in type 2 diabetic versus healthy controls. This was reverted in diabetic subjects with associated peripheral arterial disease and chronic wounds, who also exhibited higher circulating C-reactive protein and proinflammatory cytokine levels compared with diabetic controls. miR-191 and miR-200b were significantly correlated with C-reactive protein or cytokine levels in patients with diabetes mellitus. Indeed, proinflammatory stress increased endothelial- or platelet-derived secretion of miR-191 or miR-200b. In addition, dermal cells took up endothelial-derived miR-191 leading to downregulation of the miR-191 target zonula occludens-1. Altered miR-191 expression influenced angiogenesis and migratory capacities of diabetic dermal endothelial cells or fibroblasts, respectively, partly via its target zonula occludens-1. CONCLUSIONS: This study reports that (1) inflammation underlying nonhealing wounds in patients with type 2 diabetes mellitus influences plasma miRNA concentrations and (2) miR-191 modulates cellular migration and angiogenesis via paracrine regulation of zonula occludens-1 to delay the tissue repair process.

Cardiac fibroblast-derived microRNA passenger strand-enriched exosomes mediate cardiomyocyte hypertrophy.

In response to stress, the heart undergoes extensive cardiac remodeling that results in cardiac fibrosis and pathological growth of cardiomyocytes (hypertrophy), which contribute to heart failure. Alterations in microRNA (miRNA) levels are associated with dysfunctional gene expression profiles associated with many cardiovascular disease conditions; however, miRNAs have emerged recently as paracrine signaling mediators. Thus, we investigated a potential paracrine miRNA crosstalk between cardiac fibroblasts and cardiomyocytes and found that cardiac fibroblasts secrete miRNA-enriched exosomes. Surprisingly, evaluation of the miRNA content of cardiac fibroblast-derived exosomes revealed a relatively high abundance of many miRNA passenger strands ("star" miRNAs), which normally undergo intracellular degradation. Using confocal imaging and coculture assays, we identified fibroblast exosomal-derived miR-21_3p (miR-21*) as a potent paracrine-acting RNA molecule that induces cardiomyocyte hypertrophy. Proteome profiling identified sorbin and SH3 domain-containing protein 2 (SORBS2) and PDZ and LIM domain 5 (PDLIM5) as miR-21* targets, and silencing SORBS2 or PDLIM5 in cardiomyocytes induced hypertrophy. Pharmacological inhibition of miR-21* in a mouse model of Ang II-induced cardiac hypertrophy attenuated pathology. These findings demonstrate that cardiac fibroblasts secrete star miRNA-enriched exosomes and identify fibroblast-derived miR-21* as a paracrine signaling mediator of cardiomyocyte hypertrophy that has potential as a therapeutic target.

Regulatory RNAs and paracrine networks in the heart.

Cardiac hypertrophy and fibrosis are two closely related adaptive response mechanisms of the myocardium to mechanical, metabolic, and genetic stress that finally contribute to the development of heart failure (HF). This relation is based on a dynamic interplay between many cell types including cardiomyocytes and fibroblasts during disease progression. Both cell types secrete a variety of growth factors, cytokines, and hormones that influence hypertrophic cardiomyocyte growth and fibrotic fibroblast activation in a paracrine and autocrine manner. It has become evident that, aside proteinous signals, microRNAs (miRNAs) and possible other RNA species such as long non-coding RNAs are potential players in such a cell-to-cell communication. By directly acting as paracrine signals or by modulating downstream intercellular signalling mediators, miRNAs can act as moderators of the intercellular crosstalk. These small regulators can potentially be secreted in a 'mircrine' fashion, so that miRNAs can be assumed as the message itself. This review will summarize the recent findings about the paracrine crosstalk between cardiac fibroblasts and cardiomyocytes and addresses how miRNAs may be involved in this interplay. It also highlights therapeutic strategies targeting factors of pathological communication for the treatment of HF.

TWIST1 regulates the activity of ubiquitin proteasome system via the miR-199/214 cluster in human end-stage dilated cardiomyopathy.

BACKGROUND: The transcription factor TWIST1 has been described to regulate the microRNA (miR)-199/214 cluster. Genetic disruption of TWIST1 resulted in a cachectic phenotype and early death of the knock-out mice. This might be connected to the activity of the ubiquitin-proteasome-system (UPS), as miR-199a has been suggested to regulate the ubiquitin E2 ligases Ube2i and Ube2g1. METHODS: Cardiac tissue from explanted hearts of 42 patients with dilated cardiomyopathy and 20 healthy donor hearts were analysed for protein expression of TWIST1 and its inhibitors Id-1, MuRF-1 and MAFbx, the expression of miR-199a, -199b and -214, as well as the activity of the UPS by using specific fluorogenic substrates. RESULTS: TWIST1 was repressed in patients with dilated cardiomyopathy by 43% (p=0.003), while Id1 expression was unchanged. This was paralleled by a reduced expression of miR-199a by 38 ± 9% (p=0.053), miR-199b by 36 ± 13% (p=0.019) and miR-214 by 41 ± 11% (p=0.0158) compared to donor hearts. An increased peptidylglutamyl-peptide-hydrolysing activity (p<0.0001) was observed in the UPS, while the chymotrypsin-like and trypsin-like activities were unchanged. The protein levels of the rate limiting ubiquitin E3-ligases MuRF-1 and MAFbx were up-regulated (p=0.005 and p=0.0156, respectively). Mechanistically silencing of TWIST1 using siRNA in primary rat cardiomyocytes led to a down-regulation of the miR-199/214 cluster and to a subsequent up-regulation of Ube2i. CONCLUSION: The TWIST1/miR-199/214 axis is down-regulated in dilated cardiomyopathy, which is likely to play a role in the increased activity of the UPS. This may contribute to the loss of cardiac mass during dilatation of the heart.

The miRNA-212/132 family regulates both cardiac hypertrophy and cardiomyocyte autophagy.

Pathological growth of cardiomyocytes (hypertrophy) is a major determinant for the development of heart failure, one of the leading medical causes of mortality worldwide. Here we show that the microRNA (miRNA)-212/132 family regulates cardiac hypertrophy and autophagy in cardiomyocytes. Hypertrophic stimuli upregulate cardiomyocyte expression of miR-212 and miR-132, which are both necessary and sufficient to drive the hypertrophic growth of cardiomyocytes. MiR-212/132 null mice are protected from pressure-overload-induced heart failure, whereas cardiomyocyte-specific overexpression of the miR-212/132 family leads to pathological cardiac hypertrophy, heart failure and death in mice. Both miR-212 and miR-132 directly target the anti-hypertrophic and pro-autophagic FoxO3 transcription factor and overexpression of these miRNAs leads to hyperactivation of pro-hypertrophic calcineurin/NFAT signalling and an impaired autophagic response upon starvation. Pharmacological inhibition of miR-132 by antagomir injection rescues cardiac hypertrophy and heart failure in mice, offering a possible therapeutic approach for cardiac failure.