Biology subjects

Guadix, J. A.

Publications and source records attributed to Guadix, J. A..

3 recordsLinked to original sources

bioRxiv2024

Characterization and Functional Assessment of Epicardial Secretome: Epicardium-Derived Extracellular Vesicles and Matrix

AimThe epicardium, an epithelial layer covering the heart, plays pivotal roles in embryonic heart development and responses to cardiac damage. Epicardial secreted molecular agents are known to be involved in the regulation of these phenomena, but how this regulation occurs is poorly understood. In this study, we have investigated extracellular vesicle (EV) and extracellular matrix (ECM) components of epicardial secretions using a continuous mouse embryonic epicardial-derived cell (EPIC) line. Methods and resultsEpicardial-derived EVs were isolated using differential ultracentrifugation from EPIC cultured at 1% (EVs-H1%), 5% (EVs-H5%), and 21% oxygen (EVs-N). EVs protein content was determined by tandem mass tag (TMT) proteomic analysis. The results showed that epicardial-derived EVs cargo is sensitive to the oxygen level of their parenteral cells, increasing their content on glycolytic proteins. Moreover, hypoxic-derived EVs were found to both increase EPIC proliferation and affect the metabolism of Primary Human Umbilical Vein Endothelial Cells (HUVECs). On the other hand, epicardial-derived extracellular matrix (EPIC-ECM) was characterized by subjecting decellularized EPIC to shotgun proteomics and comparing it to decellularized perinatal hearts and Matrigel(R). We found that EPIC-ECM composition closely resembles that of embryonic cardiac tissue. Although the structural and basement membrane-associated proteins of EPIC-ECM were similar to those found in Matrigel(R)(R), EPIC-ECM exhibited higher protein diversity and was a more potent inducer of HUVEC proliferation. ConclusionThis work represents the first comprehensive and systematic proteomic analysis of two important components of the epicardial-derived secretome. Our experiments reveal that the epicardium responds to hypoxia by secreting EVs capable of modifying the metabolic responses of surrounding cells. Furthermore, EPIC-ECM promotes endothelial cell proliferation. These findings demonstrate the significant signaling abilities of the epicardial secretome, consistent with reports of endothelial responses following cardiac ischemic damage.

developmental biology↗

bioRxiv2022

Origin of congenital coronary arterio-ventricular fistulae from anomalous epicardial and myocardial development

AimsIn this work we investigated the embryonic origin of coronary arterio-ventricular connections, known as coronary artery fistulas (CAF), a congenital heart disease associated to postnatal and adult changes in systemic hemodynamics that may cause cardiac ischemia. Methods and resultswe have used different animal models (mouse and avian embryos) to experimentally model CAF morphogenesis. Conditional Itga4 (alpha 4 integrin) epicardial deletion in mice and cryocauterisation of chick and quail embryonic hearts disrupted epicardial development and ventricular wall growth, two essential events in coronary embryogenesis. Additional transcriptomics and in vitro analyses were performed to better understand how arterio-ventricular connections are originated in the embryonic heart. Our results show myocardial discontinuities in the developing heart of mutant mice presenting epicardial defects and avian embryos submitted to a physical cryodamage of the ventricle. These ventricular discontinuities promote the formation of endocardial pouch-like structures resembling human CAF. The structure of these CAF-like anomalies was compared with histopathological data from a human CAF, showing histomorphological and immunochemical similarities. Both human and mutant mouse hearts showed similar anomalies in the compaction of the ventricular myocardium. In vitro experiments showed the abnormal contact between the epicardium and the endocardium promote the precocious differentiation of epicardial cells to smooth muscle. ConclusionOur work suggests that myocardial discontinuities in the embryonic ventricular wall are a causative of CAF. These discontinuities would promote the early contact of the endocardium with epicardial-derived coronary progenitors at the cardiac surface, leading to ventricular endocardial extrusion, precocious differentiation of coronary smooth muscle cells, and the formation of pouch-like aberrant coronary-like structures in direct connection with the ventricular lumen. Translational perspectiveCongenital coronary artery fistulas (CAFs) lead to complications such as myocardial hypertrophy, endocarditis, heart dilatation and failure. Unfortunately, and despite their clinical relevance, the origins these congenital anomalies remain unknown. In this work, we provide information on the developmental mechanisms involved in the formation of CAFs that is relevant for their early diagnosis and prevention.

developmental biology↗

bioRxiv2021

Sporulation is dispensable for the vegetable-associated life cycle of the human pathogen Bacillus cereus

Bacillus cereus is a common food-borne pathogen that is responsible for important outbreaks of food poisoning in humans. Diseases caused by B. cereus usually exhibit two major symptoms, emetic or diarrheic, depending on the toxins produced. It is assumed that after the ingestion of contaminated vegetables or processed food, spores of enterotoxigenic B. cereus reach the intestine, where they germinate and produce the enterotoxins that are responsible for food poisoning. In our study, we observed that sporulation is required for the survival of B. cereus in leaves but is dispensable in ready-to-eat vegetables, such as endives. We demonstrate that vegetative cells of B. cereus that are originally impaired in sporulation but not biofilm formation are able to reach the intestine and cause severe disorders in a murine model. We propose that loss of part of the sporulation programme and reinforcement of structural factors related to adhesion, biofilm formation and pathogenic interaction with the host are adaptive traits of B. cereus with a life cycle primarily related to human hosts. Furthermore, our findings emphasise that the number of food poisoning cases associated with B. cereus is underestimated and suggest the need to revise the detection protocols, which are based primarily on spores and toxins.

ecology↗