Cardiac fibroblasts and mechanosensation in heart development, health and disease

The term 'mechanosensation' describes the capacity of cells to translate mechanical stimuli into the coordinated regulation of intracellular signals, cellular function, gene expression and epigenetic programming. This capacity is related not only to the sensitivity of the cells to tissue motion, but also to the decryption of tissue geometric arrangement and mechanical properties. The cardiac stroma, composed of fibroblasts, has been historically considered a mechanically passive component of the heart. However, the latest research suggests that the mechanical functions of these cells are an active and necessary component of the developmental biology programme of the heart that is involved in myocardial growth and homeostasis, and a crucial determinant of cardiac repair and disease. In this Review, we discuss the general concept of cell mechanosensation and force generation as potent regulators in heart development and pathology, and describe the integration of mechanical and biohumoral pathways predisposing the heart to fibrosis and failure. Next, we address the use of 3D culture systems to integrate tissue mechanics to mimic cardiac remodelling. Finally, we highlight the potential of mechanotherapeutic strategies, including pharmacological treatment and device-mediated left ventricular unloading, to reverse remodelling in the failing heart

Cx43 and Associated Cell Signaling Pathways Regulate Tunneling Nanotubes in Breast Cancer Cells

Altres ajuts: A. acknowledges funding from Fundación Científica Asociación Española Contra el Cáncer (IDEAS SEMILLA AECC 2020/IDEAS20033PUIG) and Instituto de Salud Carlos III co-financed by the European Regional Development Fund (ERDF) . The APC was funded by Instituto de Salud Carlos III co-financed by the European Regional Development Fund (ERDF). H.G is funded by the European Regional Development Fund (ERDF) through the Operational Program for Competitiveness Factors (COMPETE; under the projects PAC "NETDIAMOND" POCI-01-0145-FEDER-016385; HealthyAging2020 CENTRO-01-0145-FEDER-000012-N2323; POCI-01-0145-FEDER-007440, CENTRO-01-0145-FEDER-032179, CENTRO-01-0145-FEDER-032414, POCI-01-0145-FEDER-022122, FCTUID/NEU/04539/2013, UID/NEU/04539/2019, UIDB/04539/2020 and UIDP/04539/2020.Connexin 43 (Cx43) forms gap junctions that mediate the direct intercellular diffusion of ions and small molecules between adjacent cells. Cx43 displays both pro- and anti-tumorigenic properties, but the mechanisms underlying these characteristics are not fully understood. Tunneling nanotubes (TNTs) are long and thin membrane projections that connect cells, facilitating the exchange of not only small molecules, but also larger proteins, organelles, bacteria, and viruses. Typically, TNTs exhibit increased formation under conditions of cellular stress and are more prominent in cancer cells, where they are generally thought to be pro-metastatic and to provide growth and survival advantages. Cx43 has been described in TNTs, where it is thought to regulate small molecule diffusion through gap junctions. Here, we developed a high-fidelity CRISPR/Cas9 system to knockout (KO) Cx43. We found that the loss of Cx43 expression was associated with significantly reduced TNT length and number in breast cancer cell lines. Notably, secreted factors present in conditioned medium stimulated TNTs more potently when derived from Cx43-expressing cells than from KO cells. Moreover, TNT formation was significantly induced by the inhibition of several key cancer signaling pathways that both regulate Cx43 and are regulated by Cx43, including RhoA kinase (ROCK), protein kinase A (PKA), focal adhesion kinase (FAK), and p38. Intriguingly, the drug-induced stimulation of TNTs was more potent in Cx43 KO cells than in wild-type (WT) cells. In conclusion, this work describes a novel non-canonical role for Cx43 in regulating TNTs, identifies key cancer signaling pathways that regulate TNTs in this setting, and provides mechanistic insight into a pro-tumorigenic role of Cx43 in cancer

Exosomes secreted by cardiomyocytes subjected to ischaemia promote cardiac angiogenesis

Funding Information: This work was supported by European Regional Development Fund (FEDER) through the Operational Program for Competitiveness Factors (COMPETE) [HealthyAging2020 CENTRO-01-0145-FEDER-000012-N2323, POCI-01-0145-FEDER-016385, POCI-01-0145-FEDER-007440 to CNC.IBILI, POCI-01-0145-FEDER-007274 to i3S/INEB and NORTE-01-0145-FEDER-000012 to T.L.L.]; national funds through the Portuguese Foundation for Science and Technology (FCT) [PTDC/SAU-ORG/119296/2010, PTDC/ NEU-OSD/0312/2012, PESTC/ SAU/UI3282/2013-2014, MITP-TB/ECE/0013/ 2013, FCT-UID/NEU/04539/2013], PD/BD/52294/2013 to T.M.R.R., SFRH/ BD/85556/2012 (co-financed by QREN) to V.C.S]; Lisboa Portugal Regional Operational Programme (LISBOA 2020) and Norte Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement; and by INFARMED Autoridade Nacional do Medicamento e Produtos de Saúde, I.P. [FIS-FIS-2015-01_CCV_20150630-157]. Publisher Copyright: © 2017 The Author.Aims Myocardial infarction (MI) is the leading cause of morbidity and mortality worldwide and results from an obstruction in the blood supply to a region of the heart. In an attempt to replenish oxygen and nutrients to the deprived area, affected cells release signals to promote the development of new vessels and confer protection against MI. However, the mechanisms underlying the growth of new vessels in an ischaemic scenario remain poorly understood. Here, we show that cardiomyocytes subjected to ischaemia release exosomes that elicit an angiogenic response of endothelial cells (ECs). Methods and results Exosomes secreted by H9c2 myocardial cells and primary cardiomyocytes, cultured either in control or ischaemic conditions were isolated and added to ECs. We show that ischaemic exosomes, in comparison with control exosomes, confer protection against oxidative-induced lesion, promote proliferation, and sprouting of ECs, stimulate the formation of capillary-like structures and strengthen adhesion complexes and barrier properties. Moreover, ischaemic exosomes display higher levels of metalloproteases (MMP) and promote the secretion of MMP by ECs. We demonstrate that miR-222 and miR-143, the relatively most abundant miRs in ischaemic exosomes, partially recapitulate the angiogenic effect of exosomes. Additionally, we show that ischaemic exosomes stimulate the formation of new functional vessels in vivo using in ovo and Matrigel plug assays. Finally, we demonstrate that intramyocardial delivery of ischaemic exosomes improves neovascularization following MI. Conclusions This study establishes that exosomes secreted by cardiomyocytes under ischaemic conditions promote heart angiogenesis, which may pave the way towards the development of add-on therapies to enhance myocardial blood supply.publishersversionpublishe

Long COVID and the cardiovascular system—elucidating causes and cellular mechanisms in order to develop targeted diagnostic and therapeutic strategies: a joint Scientific Statement of the ESC Working Groups on Cellular Biology of the Heart and Myocardial and Pericardial Diseases

Long COVID has become a world-wide, non-communicable epidemic, caused by long-lasting multiorgan symptoms that endure for weeks or months after SARS-CoV-2 infection has already subsided. This scientific document aims to provide insight into the possible causes and therapeutic options available for the cardiovascular manifestations of long COVID. In addition to chronic fatigue, which is a common symptom of long COVID, patients may present with chest pain, ECG abnormalities, postural orthostatic tachycardia, or newly developed supraventricular or ventricular arrhythmias. Imaging of the heart and vessels has provided evidence of chronic, post-infectious perimyocarditis with consequent left or right ventricular failure, arterial wall inflammation, or microthrombosis in certain patient populations. Better understanding of the underlying cellular and molecular mechanisms of long COVID will aid in the development of effective treatment strategies for its cardiovascular manifestations. A number of mechanisms have been proposed, including those involving direct effects on the myocardium, microthrombotic damage to vessels or endothelium, or persistent inflammation. Unfortunately, existing circulating biomarkers, coagulation, and inflammatory markers, are not highly predictive for either the presence or outcome of long COVID when measured 3 months after SARS-CoV-2 infection. Further studies are needed to understand underlying mechanisms, identify specific biomarkers, and guide future preventive strategies or treatments to address long COVID and its cardiovascular sequelae

Fistula Recurrence: A Clinical Reality after Successful Endoscopic Closure of Laparoscopic Sleeve Gastrectomy Fistulas

Background and Aims: Laparoscopic sleeve gastrectomy (LSG)-related fistulas are important and potentially fatal complications. We aimed at determining the incidence, predictive factors, and management of recurrence of post-LSG fistulas. Methods: This is a retrospective cohort study of 12 consecutive patients with LSG fistulas managed endoscopically between 2008 and 2013. We analyzed factors associated with recurrence of post-LSG fistulas and the efficacy of a primarily endoscopic approach to manage fistula recurrence. Results: The average age at fistula detection after LSG was 43.3 ± 10.9 years, and 10 (83%) patients were female. The median interval between surgery and initial fistula detection was 14 (4–145) days. Fistulas were located at the gastric cardia in 9/12 patients. A median of 4 (1–10) endoscopies were performed per patient until all fistulas were successfully closed. The median follow-up was 30.5 (15–72) months. Fistula recurrence was detected in 3 (25%) female patients with an average age of 31.7 ± 7.9 years after a median of 119 (50–205) days of the initial fistula closure. Fistulas in all 3 patients recurred at the gastric cardia and were successfully managed endoscopically. There was a second recurrence in 1 patient after 6 months, and she was re-operated with anastomosis of a jejunal loop at the site of the fistula orifice at the gastric cardia. We did not find any factors at initial fistula detection that were significantly associated with fistula recurrence. There were no deaths related to initial fistula after LSG and fistula recurrence. Conclusions: A primarily endoscopic approach is an effective and safe method for the management of fistulas after LSG. Fistula recurrence occurred in 25% of patients and was managed endoscopically. Key Messages: Although we could not define predictive factors of post-LSG fistula recurrence, it is a clinical reality and can be managed endoscopically

Circulating blood cells and extracellular vesicles in acute cardioprotection

During an ST-elevation myocardial infarction (STEMI), the myocardium undergoes a prolonged period of ischaemia. Reperfusion therapy is essential to minimize cardiac injury but can paradoxically cause further damage. Experimental procedures to limit ischaemia and reperfusion (IR) injury have tended to focus on the cardiomyocytes since they are crucial for cardiac function. However, there is increasing evidence that non-cardiomyocyte resident cells in the heart (as discussed in a separate review in this Spotlight series) as well as circulating cells and factors play important roles in this pathology. For example, erythrocytes, in addition to their main oxygen-ferrying role, can protect the heart from IR injury via the export of nitric oxide bioactivity. Platelets are well-known to be involved in haemostasis and thrombosis, but beyond these roles, they secrete numerous factors including sphingosine-1 phosphate (S1P), platelet activating factor (PAF) and cytokines that can all strongly influence the development of IR injury. This is particularly relevant given that most STEMI patients receive at least one type of platelet inhibitor. Moreover, there are large numbers of circulating vesicles in the blood, including microvesicles and exosomes, which can exert both beneficial and detrimental effects on IR injury. Some of these effects are mediated by the transfer of miRNA to the heart. Synthetic miRNA molecules may offer an alternative approach to limiting the response to IR injury. We discuss these and other circulating factors, focussing on potential therapeutic targets relevant to IR injury. Given the prevalence of co-morbidities such as diabetes in the target patient population, their influence will also be discussed. This article is part of a Cardiovascular Research Spotlight Issue entitled 'Cardioprotection Beyond the Cardiomyocyte', and emerged as part of the discussions of the European Union (EU)-CARDIOPROTECTION Cooperation in Science and Technology (COST) Action, CA16225

Targeting mitochondrial fusion and fission proteins for cardioprotection

New treatments are needed to protect the myocardium against the detrimental effects of acute ischaemia/reperfusion (IR) injury following an acute myocardial infarction (AMI), in order to limit myocardial infarct (MI) size, preserve cardiac function and prevent the onset of heart failure (HF). Given the critical role of mitochondria in energy production for cardiac contractile function, prevention of mitochondrial dysfunction during acute myocardial IRI may provide novel cardioprotective strategies. In this regard, the mitochondrial fusion and fissions proteins, which regulate changes in mitochondrial morphology, are known to impact on mitochondrial quality control by modulating mitochondrial biogenesis, mitophagy and the mitochondrial unfolded protein response. In this article, we review how targeting these inter-related processes may provide novel treatment targets and new therapeutic strategies for reducing MI size, preventing the onset of HF following AMI

Kazrin C regulates endocytic recycling pathways and controls cell migration

Trabajo presentado en el EMBO Workshop: Cell polarity and membrane dynamics, celebrado en Sant Feliu de Guixols, Girona, del 4 al 9 de junio de 2017Kazrin C was identified in a screening for human proteins that affect endocytic traffic when overexpressed. Indeed, its depletion delays the transfer of Transferrin from sorting to the Rab11 containing endosomes, whereas it accelerates a short loop recycling pathway. Kazrin C is localized at endosomes containing Transferrin and Rab4 and it directly interacts with components of the clathrin coat, such as clathrin and ¿-adaptin, and with components of the actin cytoskeleton, such as the ARP2/3 complex and WASH. In addition, it interacts with several phosphoinositides, which have a role in the regulation of endocytic trafficking. Our hypothesis is that Kazrin C favours the long recycling route in opposition to the short recycling route, either by controlling actin polymerization, by influencing the endosomal phosphoinositide content and/or by promoting loading of cargo into AP-1 and clathrin transport intermediates. The balance between these two routes is known to be important in the control of cell migration: ¿5ß1 integrin is recycled through the long route and its presence at the plasma membrane promotes random migration, while ¿vß3 follows the short route and promotes directionally persistent migration. In agreement with this and our hypothesis, we have observed an increased persistance in the migration of Kazrin C depleted cells when compared to control cells.N