Autonomous metabolic reprogramming and oxidative stress characterize endothelial dysfunction in acute myocardial infarction

Background: Compelling evidence has accumulated on the role of oxidative stress on the endothelial cell (EC) dysfunction underlying acute coronary syndrome. However, unveiling the underlying metabolic determinants has been hampered by the scarcity of appropriate cell models to address cell-autonomous mechanisms of ED dysfunction. Methods: We have generated endothelial cells derived from thrombectomy specimens from patients affected with acute myocardial infarction (AMI) and conducted phenotypical and metabolic characterization, focused on central carbon metabolism. Results: AMI-derived endothelial cells (AMIECs), but not control healthy coronary endothelial cells, display impaired growth, migration and tubulogenesis. Metabolically, AMIECs displayed augmented reactive oxygen species (ROS) and glutathione intracellular content, along with a diminished glucose consumption coupled to high lactate production. Consistent with diminished glycolysis in AMIECs, the protein levels of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase type 3, PFKFB3, were downregulated. In contrast, PFKFB4 levels were upregulated, suggesting a shunting of glycolysis towards the pentose phosphate pathway (PPP), supported by upregulation in AMIECs of G6PD, the key enzyme in the oxidative branch of the PPP. Further, the glutaminolytic enzyme GLS was upregulated in AMIECs, providing a mechanistic explanation for the observed increase in glutathione content. Finally, AMIECs displayed a significantly higher mitochondrial membrane potential than control ECs, which, together with high ROS levels, suggest a highly coupled mitochondrial activity in patient ECs. Conclusions: We suggest high mitochondrial proton coupling underlies the abnormally high production of ROS, balanced by PPP- and glutaminolysis-driven synthesis of glutathione, as a primary, cell-autonomous abnormality driving EC dysfunction in AMI. Funding: European Commission Horizon 2020; CIBER- Carlos III National Institute of Health, Spain; Ministerio de Economia y Competitividad (MINECO) and Ministerio de Ciencia e Innovación, Spain; Generalitat de Catalunya-AGAUR, Catalonia; Plataforma Temática Interdisciplinar Salud Global (PTI-SG), Spain; British Heart Foundation, UK. </p

Metabolic Alterations in Cardiopulmonary Vascular Dysfunction

Cardiovascular diseases (CVD) are the leading cause of death worldwide. CVD comprise a range of diseases affecting the functionality of the heart and blood vessels, including acute myocardial infarction (AMI) and pulmonary hypertension (PH). Despite their different causative mechanisms, both AMI and PH involve narrowed or blocked blood vessels, hypoxia, and tissue infarction. The endothelium plays a pivotal role in the development of CVD. Disruption of the normal homeostasis of endothelia, alterations in the blood vessel structure, and abnormal functionality are essential factors in the onset and progression of both AMI and PH. An emerging theory proposes that pathological blood vessel responses and endothelial dysfunction develop as a result of an abnormal endothelial metabolism. It has been suggested that, in CVD, endothelial cell metabolism switches to higher glycolysis, rather than oxidative phosphorylation, as the main source of ATP, a process designated as the Warburg effect. The evidence of these alterations suggests that understanding endothelial metabolism and mitochondrial function may be central to unveiling fundamental mechanisms underlying cardiovascular pathogenesis and to identifying novel critical metabolic biomarkers and therapeutic targets. Here, we review the role of the endothelium in the regulation of vascular homeostasis and we detail key aspects of endothelial cell metabolism. We also describe recent findings concerning metabolic endothelial cell alterations in acute myocardial infarction and pulmonary hypertension, their relationship with disease pathogenesis and we discuss the future potential of pharmacological modulation of cellular metabolism in the treatment of cardiopulmonary vascular dysfunction. Although targeting endothelial cell metabolism is still in its infancy, it is a promising strategy to restore normal endothelial functions and thus forestall or revert the development of CVD in personalized multi-hit interventions at the metabolic level

Metabolic alterations in cardiopulmonary vascular dysfunction

Cardiovascular diseases (CVD) are the leading cause of death worldwide. CVD comprise a range of diseases affecting the functionality of the heart and blood vessels, including acute myocardial infarction (AMI) and pulmonary hypertension (PH). Despite their different causative mechanisms, both AMI and PH involve narrowed or blocked blood vessels, hypoxia, and tissue infarction. The endothelium plays a pivotal role in the development of CVD. Disruption of the normal homeostasis of endothelia, alterations in the blood vessel structure, and abnormal functionality are essential factors in the onset and progression of both AMI and PH. An emerging theory proposes that pathological blood vessel responses and endothelial dysfunction develop as a result of an abnormal endothelial metabolism. It has been suggested that, in CVD, endothelial cell metabolism switches to higher glycolysis, rather than oxidative phosphorylation, as the main source of ATP, a process designated as the Warburg effect. The evidence of these alterations suggests that understanding endothelial metabolism and mitochondrial function may be central to unveiling fundamental mechanisms underlying cardiovascular pathogenesis and to identifying novel critical metabolic biomarkers and therapeutic targets. Here, we review the role of the endothelium in the regulation of vascular homeostasis and we detail key aspects of endothelial cell metabolism. We also describe recent findings concerning metabolic endothelial cell alterations in acute myocardial infarction and pulmonary hypertension, their relationship with disease pathogenesis and we discuss the future potential of pharmacological modulation of cellular metabolism in the treatment of cardiopulmonary vascular dysfunction. Although targeting endothelial cell metabolism is still in its infancy, it is a promising strategy to restore normal endothelial functions and thus forestall or revert the development of CVD in personalized multi-hit interventions at the metabolic level

Dominant induction of the inflammasome by the SARS-CoV-2 accessory protein ORF9b, abrogated by small-molecule ORF9b homodimerization inhibitors

Viral accessory proteins play critical roles in viral escape form host innate immune responses and in viral inflammatory pathogenesis. Here we show that the SARS-CoV-2 accessory protein, ORF9b, but not other SARS-CoV-2 accessory proteins (ORF3a, ORF3b, ORF6, ORF7, ORF8, ORF9c, ORF10), strongly activates inflammasomedependent caspase-1 in A549 lung carcinoma cells and THP-1 monocyte-macrophage cells. Exposure to lipopolysaccharide (LPS) and ATP additively enhanced the activation of caspase-1 by ORF9b, suggesting that ORF9b and LPS follow parallel pathways in the activation of the inflammasome and caspase-1. Following rational in silico approaches, we have designed small molecules capable of inhibiting the homodimerization of ORF9b, which experimentally inhibited ORF9b-ORF9b homotypic interactions, caused mitochondrial eviction of ORF9b, inhibited ORF9b-induced activation of caspase-1 in A549 and THP-1 cells, cytokine release in THP-1 cells, and restored type I interferon (IFN-I) signaling suppressed by ORF9b in both cell models. These small molecules are first-in-class compounds targeting a viral accessory protein critical for viral-induced exacerbated inflammation and escape from innate immune responses, with the potential of mitigating the severe immunopathogenic damage induced by highly pathogenic coronaviruses and restoring antiviral innate immune responses curtailed by viral infection.This work was funded by the Spanish National Research Council (CSIC, project numbers CSIC-COV19-006, CSIC-COV-19-201, 202020E079 and 202320E187), the Catalan Agency for Management of University and Research Grants (AGAUR, 2020PANDE00048, 2021SGR1490, 2021SGR00350), the CSIC’s Global Health Platform (PTI Salud Global), The Networked Center for Biomedical Research in Liver and Digestive Diseases (CIBER-EHD), the Spanish Structures and Excellence María de Maeztu program (CEX2021-001202-M) and the European Commission-Next Generation EU (Regulation EU 2020/2094).N

Inflammasome activation by SARS-CoV-2 accessory protein: Development of novel inhibitors of the SARS-CoV-2 accessory protein ORF9b

1 p.-5 fig.SARS-CoV-2 can activate the inflammasome, which, when unbridled, contributes to pathogenic inflammatory responses and to severe COVID-19. Several SARS-CoV-2 components have been shown to participate in this activation. Here, we have systematically assayed SARS-CoV-2 accessory proteins (ORF3a, ORF3b, ORF6, ORF7,ORF8, ORF9b, ORF9c and ORF10) for their ability to modulate inflammasome activity. We have found that among all accessory proteins, only ORF9b, a protein that locates in mitochondria, triggers a strong activation of caspase-1 activity and cytokine release in A549 lung epithelial cells and THP-1 monocyte-macrophage cells. This induction is observed both by transducing ORF9b alone or upon concomitant transduction of all accessory proteins. Based on the solved structure of ORF9b, we have conducted an in silico drug discovery effort to identify small molecules capable of disrupting the ORF9b homodimer and to attenuate its observed activity. Iterative steps of blind massive docking and molecular dynamics led to the identification of small molecules predicted to prevent ORF9b homodimeric interactions. This prediction was experimentally validated by means of surface plasmon resonance, yielding two active molecules. These molecules showed a potent inhibition of ORF9b-induced caspase-1 activation and cytokine release, and caused a remarkable eviction of ORF9b from mitochondria. These novel first-in-class ORF9b inhibitors are currently being tested for their ability to mitigate viral cytopathogenic effects.Peer reviewe

MicroRNA-200, associated with metastatic breast cancer, promotes traits of mammary luminal progenitor cells

MicroRNAs are critical regulators of gene networks in normal and abnormal biological processes. Focusing on invasive ductal breast cancer (IDC), we have found dysregulated expression in tumor samples of several microRNAs, including the miR-200 family, along progression from primary tumors to distant metastases, further reflected in higher blood levels of miR-200b and miR-7 in IDC patients with regional or distant metastases relative to patients with primary node-negative tumors. Forced expression of miR-200s in MCF10CA1h mammary cells induced an enhanced epithelial program, aldehyde dehydrogenase (ALDH) activity, mammosphere growth and ability to form branched tubuloalveolar structures while promoting orthotopic tumor growth and lung colonization in vivo. MiR-200s also induced the constitutive activation of the PI3K-Akt signaling through downregulation of PTEN, and the enhanced mammosphere growth and ALDH activity induced in MCF10CA1h cells by miR-200s required the activation of this signaling pathway. Interestingly, the morphology of tumors formed in vivo by cells expressing miR-200s was reminiscent of metaplastic breast cancer (MBC). Indeed, the epithelial components of MBC samples expressed significantly higher levels of miR-200s than their mesenchymal components and displayed a marker profile compatible with luminal progenitor cells. We propose that microRNAs of the miR-200 family promote traits of highly proliferative breast luminal progenitor cells, thereby exacerbating the growth and metastatic properties of transformed mammary epithelial cells

MicroRNA-200, associated with metastatic breast cancer, promotes traits of mammary luminal progenitor cells

MicroRNAs are critical regulators of gene networks in normal and abnormal biological processes. Focusing on invasive ductal breast cancer (IDC), we have found dysregulated expression in tumor samples of several microRNAs, including the miR-200 family, along progression from primary tumors to distant metastases, further reflected in higher blood levels of miR-200b and miR-7 in IDC patients with regional or distant metastases relative to patients with primary node-negative tumors. Forced expression of miR-200s in MCF10CA1h mammary cells induced an enhanced epithelial program, aldehyde dehydrogenase (ALDH) activity, mammosphere growth and ability to form branched tubuloalveolar structures while promoting orthotopic tumor growth and lung colonization in vivo. MiR-200s also induced the constitutive activation of the PI3K-Akt signaling through downregulation of PTEN, and the enhanced mammosphere growth and ALDH activity induced in MCF10CA1h cells by miR-200s required the activation of this signaling pathway. Interestingly, the morphology of tumors formed in vivo by cells expressing miR-200s was reminiscent of metaplastic breast cancer (MBC). Indeed, the epithelial components of MBC samples expressed significantly higher levels of miR-200s than their mesenchymal components and displayed a marker profile compatible with luminal progenitor cells. We propose that microRNAs of the miR-200 family promote traits of highly proliferative breast luminal progenitor cells, thereby exacerbating the growth and metastatic properties of transformed mammary epithelial cells

Characterization of Endothelial Cells dysfunction associated to Acute Myocardial Infarction: modulation of metabolic pathways as a new therapeutic approach

[eng] The endothelium plays a pivotal role in the development of cardiovascular disease (CVD) and emerging evidence indicates that pathological blood vessel responses and endothelial dysfunction are associated with metabolic alterations in endothelial cells (ECs). This project aims at performing a complete characterization of the metabolic profiles of an endothelial pathological Acute Myocardial Infarction (AMI) model of 8 patients. The results discussed throughout this thesis are part of this attempt, and brought to the identification of the insights and causes of the AMI pathology, as a consequence of the metabolic alterations related to the endothelium dysfunction which occurs in patients. Due to patients variability, finding a single and clear mechanism among all is quite hard to grasp. However, we have been able to find some metabolic feature to be exploited as possible biomarker for the identification of this CVD. Patients cells presented a low proliferation rate and unveiled a dependence to mitochondrial metabolism, which results in an increased ROS-oxidative stress. Consequently, these cells express increased level of glutathione that supplies the antioxidant defense and prevent ROS (Reactive oxygen species) accumulation. Glutamine seems to play a key role in this AMI model; first of all it is necessary for these cells to display a proper mitochondrial function and in addition, it is required for the synthesis of glutathione as antioxidant against the high level of ROS detected. Additionally, finding a higher content of glutaminase C (GAC) in patients, has opened the possibility that these cells rely more on glutaminase reaction for their survival, and this dependence gathered with the augmented need to neutralize the acidic pH , which results from the increased lactate production, by the ammonia molecules released from glutamine metabolism. This findings point that in AMI model is occurring a metabolic adaptation similar to the Warburg effect, usually described in cancer cells. In the frame of finding the same origin among different pathologies ,in the second part of this work we focused on the crosstalk between dysfunctional endothelium and tumor microenvironment. Moreover, nowadays there is an increasing interest in supporting the existence of a link between cardiovascular pathologies and cancer. One of the wide possibilities which lies these two lethal morbidities is a an alteration of the DNA repair system, crucial for the recovery of the healthy cells against the diseased ones, when a pathological event takes place. Through this study we found that: alternative splicing governs cell‐type regulated expression of variant forms of mRNAs and their encoded proteins that exert differential function. So, employing cancer cell model in which distinct tumor cell subpopulations display differentiated epithelial or mesenchymal phenotype, we have identified alternatively spliced mRNAs with potential impact on the self‐renewal capacities of these cell subpopulations. More in details, among all the genetic characters which can be involved in this process, we provide evidences that RAP80 (UIMC1), an adaptor protein with critical functions in homology-dependent DNA repair (HDR), is expressed as alternatively spliced isoforms in epithelial and mesenchymal cells, as a function of ESRP1/2 expression. More specifically, we have found that the ratio of expression of a full-length isoform to a short isoform of RAP80 is significantly higher in epithelial cells than mesenchymal cells in a prostate cancer cell model for EMT. RAP80 contains a region required for interaction with Abraxas , a core component of the BRCA1-A complex involved in DNA-damage repair. We propose that the ratio of full-length RAP80 to the short isoform lacking AIR is a new mechanism for the regulation of HDR mediated by BRCA1. A higher long/short RAP80 isoform ratio will favor, and lower ratios will counter, the recruitment of BRCA1-A complexes to DSBs

Metabolic Reprogramming and Dependencies Associated with Epithelial Cancer Stem Cells Independent of the Epithelial-Mesenchymal Transition Program

Esther Aguilar et al.In solid tumors, cancer stem cells (CSCs) can arise independently of epithelial-mesenchymal transition (EMT). In spite of recent efforts, the metabolic reprogramming associated with CSC phenotypes uncoupled from EMT is poorly understood. Here, by using metabolomic and fluxomic approaches, we identify major metabolic profiles that differentiate metastatic prostate epithelial CSCs (e-CSCs) from non-CSCs expressing a stable EMT. We have found that the e-CSC program in our cellular model is characterized by a high plasticity in energy substrate metabolism, including an enhanced Warburg effect, a greater carbon and energy source flexibility driven by fatty acids and amino acid metabolism and an essential reliance on the proton buffering capacity conferred by glutamine metabolism. An analysis of transcriptomic data yielded a metabolic gene signature for our e-CSCs consistent with the metabolomics and fluxomics analyses that correlated with tumor progression and metastasis in prostate cancer and in 11 additional cancer types. Interestingly, an integrated metabolomics, fluxomics, and transcriptomics analysis allowed us to identify key metabolic players regulated at the post-transcriptional level, suggesting potential biomarkers and therapeutic targets to effectively forestall metastasis.This work was supported by funds to M.C. from MICINN (SAF2011–25726 and SAF2014-56059-R, European Comission FEDER-Una manera de hacer Europa); Agència Catalana d'Ajuts Universitaris i de Recerca (AGAUR) (2014SGR-1017), ICREA Foundation (Generalitat de Catalunya) and European Commission (Metaflux, PITN-GA-2010-264780); to T.M.T. from MICINN (SAF2011-24686), MINECO (SAF2012-40017-C02-01, European Comission FEDER-Una manera de hacer Europa), AGAUR (2009SGR1482), and Xarxa de Referència en Biotecnologia; and to D.H. and F.M. from NIH (5R01CA158921-02). E.A. was supported by a fellowship from the MECD and a travel grant from RTICC; I.M.M. by a EC Marie Curie grant (Metaflux, PITN-GA-2010-264780)Peer Reviewe