Biology subjects

Zodda, E.

Publications and source records attributed to Zodda, E..

3 recordsLinked to original sources

bioRxiv2024

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 inflammasome-dependent 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.

microbiology↗

bioRxiv2024

Glutaminase as a metabolic target of choice to counter acquired resistance to Palbociclib by colorectal cancer cells

Several mechanisms of resistance of cancer cells to cyclin-dependent kinase inhibitors (CDKi) have been identified, including the upregulation of metabolic regulators such as glutaminase. However, whether such mechanisms and targets are optimal has not been determined. Here, we have systematically analyzed metabolic reprogramming in colorectal cancer cells exposed to Palbociclib, a CDKi selectively targeting CDK4/6, or Telaglenestat, a selective glutaminase inhibitor. Through multiple approaches, we show that Palbociclib and Telaglenestat elicit complementary metabolic responses and are thus uniquely suited to counter the metabolic reprogramming induced by the reciprocal drug. As such, while Palbociclib induced reduced tumor growth in vivo, and Telaglenestat did not show a significant effect, the drug combination displayed a strong synergistic effect on tumor growth. Likewise, initial responses to Palbociclib were followed by signs of adaptation and resistance, which were prevented by combining Palbociclib with Telaglenestat. In conclusion, combination with Telaglenestat optimally forestalls acquired resistance to Palbociclib in cancer cells.

cancer biology↗

bioRxiv2023

Cell-autonomous metabolic reprogramming and oxidative stress underlie endothelial dysfunction in acute myocardial infarction

Compelling evidence has accumulated for the role of oxidative stress on the endothelial cell (EC) dysfunction underlying acute coronary syndromes. However, understanding the metabolic determinants of EC dysfunction has been hampered by the scarcity of appropriate cell models. Here, we have generated and phenotypically characterized EC derived from thrombectomy specimens in patients with acute myocardial infarction (AMI). We have found that AMI-derived endothelial cells (AMIECs), but not control EC from health coronary arteries, display impaired growth, migration and tubulogenesis. These phenotypic abnormalities were accompanied with metabolic abnormalities including augmentation of reactive oxygen species (ROS) and glutathione intracellular content, along with diminished glucose consumption coupled to increased lactate production. In AMIECs, the protein levels of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase type 3, PFKFB3, were downregulated, while those of PFKFB4 were upregulated, suggesting a shunting of glycolysis towards the pentose phosphate pathway (PPP) in the pathological ECs. PPP overactivation was further supported by upregulation of G6PD in AMIECs, the key enzyme in the oxidative branch of the PPP, which supplies the bulk of NADPH reducing equivalents necessary for the reduction/turnover and lipid synthesis.. Further, the glutaminolytic enzyme glutaminase (GLS) was upregulated in AMIECs, providing a mechanistic explanation for the observed increase in glutathione content. Finally, AMIECs had higher mitochondrial membrane potential than control ECs, which, together with high ROS levels, suggest a highly coupled mitochondrial activity in patient ECs. We suggest that high proton coupling underlies the abnormally high production of ROS, balanced by PPP-driven glutathione turnover, as a primary, cell-autonomous abnormality driving EC dysfunction in AMI.

cell biology↗