Biology subjects

Escobar, B.

Publications and source records attributed to Escobar, B..

6 recordsLinked to original sources

bioRxiv2024

Vascular HIF2 signaling prevents cardiomegaly, alveolar congestion and capillary remodeling during chronic hypoxia

Hypoxia is associated with the onset of cardiovascular diseases including cardiac hypertrophy and pulmonary arterial hypertension (PAH). Endothelial HIF2 signaling mediates pulmonary arterial remodeling and subsequent right ventricular systolic pressure (RVSP) elevation during chronic hypoxia, encouraging novel therapeutic opportunities for PAH based on specific HIF2 inhibitors. Nevertheless, HIF2 relevance beyond the pulmonary endothelium or in the cardiac adaptation to hypoxia remains elusive. Wilms tumor 1 lineage contributes to heart and lung vascular compartments including pericytes, endothelial and smooth muscle cells. Here we describe the response to chronic hypoxia of a novel HIF2 mutant mouse model in the Wt1 lineage (Hif2/Wt1 cKO). Hif2/Wt1 cKO is protected against pulmonary remodeling and increased RVSP induced by hypoxia, but displays alveolar congestion, inflammation and hemorrhages associated with microvascular instability. Furthermore, lack of HIF2 in the Wt1 lineage leads to cardiomegaly, capillary remodeling, right and left ventricular hypertrophy, systolic dysfunction and left ventricular dilation, suggesting pulmonary-independent cardiac direct roles of HIF2 in hypoxia. These structural defects are partially restored upon reoxygenation, while functional parameters remain altered. Our results suggest that cardiopulmonary HIF2 signaling prevents excessive vascular proliferation during chronic hypoxia and define novel protective roles of HIF2 to warrant stable microvasculature and organ function.

pathology↗

bioRxiv2024

Activation of HIF2 leads to vascular remodeling and inflammation, coronary thrombosis and arterial dilation, recapitulating cardiac involvement of Kawasaki disease.

Backgroundglobal deletion of Vhl leads to vascular defects and early lethality, precluding the study of VHL/HIF signaling during coronary formation and homeostasis. Hypoxia pathway has been associated with cardiovascular diseases involving inflammation and vascular remodeling like atherosclerosis, but its role in Kawasaki Disease (KD) remains unknown. Coronary dilatation and vessel rupture are the most serious complications of KD, while the molecular mechanisms underlying these cardiac events remain poorly understood. Here we aim to determine the function of VHL/HIF pathway in the development of cardiovascular defects and its role in KD. MethodsWe generated a new mouse model to genetically hyperactivate hypoxia pathway in progenitors contributing to coronary vessels and cardiac fibroblasts (Vhl/Wt1). We characterized the model by means of echocardiography, magnetic resonance imaging, histological analysis and molecular approaches. Human cardiac tissue from KD individuals suffering fatal coronary aneurysm were screened for HIF signaling and inflammatory markers by immunohistochemistry. Resultsconditional Vhl KO do not undergo developmental abnormalities but displays cardiomegaly and epicardial vascular defects, with cardiac hypertrophy and progressive coronary diameter increase, as well as pericardial hemorrhage and systemic inflammation early after birth. Histological characterization reveals inflammation of coronary arteries, vascular remodeling with elastin breaks and dilatation, increased perivascular fibrosis and smooth muscle cells death, together with high incidence of intracoronary thrombus formation. In addition, the mutants display vascular calcification and severe cardiac inflammation and interstitial hemorrhages, dying suddenly between 15-20 weeks of age due to vessel rupture. Simultaneous elimination of HIF2 and VHL prevents the cardiovascular abnormalities displayed by single cVhl KO, highlighting the essential role of HIF2 in coronary instability and vascular inflammation. Histological characterization of human cardiac samples shows positive signal for HIF1 and specially HIF2, in the coronary lesions and its surroundings in regions with high inflammatory infiltration, confirming the activation of hypoxia signaling in KD patients with cardiovascular complications. ConclusionsOur data demonstrate the importance of HIF2 signaling in the development of coronary inflammation and vascular remodeling and provide new evidences connecting low oxygen tensions with cardiovascular lesions occurring during the onset of the most severe cases of KD. Furthermore, the Vhl/Wt1 mouse generated recapitulates cardiac features of KD with critical heart complications, providing a new platform to uncover unknown aspects of KD pathogenesis.

pathology↗

bioRxiv2021

DIETARY RESCUE OF ADULT BEHAVIORAL DEFICITS IN THE FMR1 KNOCKOUT MOUSE

The current study aimed to further address important questions regarding the therapeutic efficacy of omega-3 fatty acids for various behavioral and neuroimmune aspects of the Fmr1 phenotype. To address these questions, our experimental design utilized two different omega-3 fatty acid administration timepoints, compared to both standard laboratory chow controls ("Standard") and a diet controlling for the increase in fat content ("Control Fat"). In the first paradigm, post-weaning supplementation (after postnatal day 21) with the omega-3 fatty acid diet ("Omega-3") reversed deficits in startle threshold, but not deficits in prepulse inhibition, and the effect on startle threshold was not specific to the Omega-3 diet. However, post-weaning supplementation with both experimental diets also impaired acquisition of a fear response, recall of the fear memory and contextual fear conditioning compared to the Standard diet. The post-weaning Omega-3 diet reduced hippocampal expression of IL-6 and this reduction of IL-6 was significantly associated with diminished performance in the fear conditioning task. In the prenatal experimental paradigm, the Omega-3 diet attenuated hyperactivity and acquisition of a fear response. Additionally, prenatal exposure to the Control Fat diet (similar to a "Western" diet) further diminished nonsocial anxiety in the Fmr1 knockout. This study provides significant evidence that dietary fatty acids throughout the lifespan can significantly impact the behavioral and neuroimmune phenotype of the Fmr1 knockout model.

neuroscience↗

bioRxiv2020

Activation of amino acid metabolic program in response to impaired glycolysis in cardiac HIF1 deficient mice

Hypoxia is an important environmental cue in heart development. Despite of extensive characterization of gain and loss of function models, there is disagreement about the impact of HIF1 elimination in cardiac tissue. Here, we used a new conditional knock out of Hif1a in NKX2.5 cardiac progenitors to assess the morphological and functional consequences of HIF1 loss in the developing heart. By combining histology, electron microscopy and high-throughout genomics, proteomics and metabolomics, we found that deletion of Hif1a leads to impaired embryonic glycolysis without influencing cardiomyocyte proliferation and results in an increased mitochondrial number, activation of a transient amino acid response and upregulation of HIF2 and ATF4 by E12.5. Hif1a mutants display normal fatty acid oxidation metabolic profile and do not show any sign of cardiac dysfunction in the adulthood. Our results demonstrate that HIF1 signaling is dispensable for heart development and reveal the metabolic flexibility of the embryonic myocardium, opening the potential application of alternative energy sources as therapeutic interventions during ischemic events.

developmental biology↗

bioRxiv2019

Metabolic reprogramming from glycolysis to amino acid utilization in cardiac HIF1α deficient mice.

RationaleHypoxia is an important environmental cue implicated in several physiopathological processes, including heart development. Several mouse models of activation or inhibition of hypoxia have been previously described. While gain of function models have been extensively characterized and indicate that HIF1 signaling needs to be tightly regulated to ensure a proper cardiac development, there is lack of consensus in the field about the functional outcomes of HIF1 loss.\n\nObjectiveIn this study, we aim to assess the consequences of cardiac deletion of HIF1 during heart development and identify the cardiac adaptations to HIF1 loss.\n\nMethods and ResultsHere, we used a conditional deletion model of Hif1a in NKX2.5+ cardiac progenitors. By a combination of histology, electron microscopy, massive gene expression studies, proteomics, metabolomics and cardiac imaging, we found that HIF1 is dispensable for cardiac development. Hif1a loss results in glycolytic inhibition in the embryonic heart without affecting normal cardiac growth. However, together with a premature increase in mitochondrial number by E12.5, we found global upregulation of amino acid transport and catabolic processes. Interestingly, this amino acid catabolism activation is transient and does not preclude the normal cardiac metabolic switch towards fatty acid oxidation (FAO) after E14.5. Moreover, Hif1a loss is accompanied by an increase in ATF4, described as an important regulator of several amino acid transporters.\n\nConclusionsOur data indicate that HIF1 is not required for normal cardiac development and suggest that additional mechanisms can compensate Hif1a loss. Moreover, our results reveal the metabolic flexibility of the embryonic heart at early stages of development, showing the capacity of the myocardium to adapt its energy source to satisfy the energetic and building blocks demands to achieve normal cardiac growth and function. This metabolic reprograming might be relevant in the setting of adult cardiac failure.

developmental biology↗

bioRxiv2018

Plk1 overexpression suppresses tumor development by inducing chromosomal instability

Polo-like kinase 1 (Plk1) is a protein kinase currently considered as an attractive cancer target due to its critical role in the cell division cycle. Plk1 is overexpressed in a wide spectrum of human tumors, being frequently considered as an oncogene. However, its contribution to tumor development is unclear. Using a new inducible knock-in mouse model we report here that Plk1 overexpression does not favor cell proliferation but rather results in abnormal chromosome segregation and cytokinesis, leading to the formation of polyploid cells with reduced proliferative potential. Mechanistically, these cytokinesis defects correlate with defective loading of Cep55 and ESCRT complexes to the abscission bridge during cytokinesis in a Plk1 kinase-dependent manner. In vivo, elevated levels of Plk1 markedly prevent the development of mammary gland tumors induced either by KrasG12D or Her2, in the presence of increased rates of chromosome instability. In patients, higher Plk1 expression levels are associated with significantly increased overall survival in breast cancer subtypes. These data suggest that, despite the therapeutic benefits of inhibiting Plk1 due to its essential role in tumor cell cycles, Plk1 overexpression has tumor suppressive properties by perturbing mitotic progression and cytokinesis.

cancer biology↗