Shenoy, S. K. | Search bioRxiv

bioRxiv2025

Inflammation-induced endothelial cell activation and angiogenic sprouting are downmodulated by ubiquitin-specific peptidase 20

Nuclear factor-{kappa}B (NF-{kappa}B) mediates inflammation-driven angiogenesis, which promotes the growth of atherosclerotic plaques and tumors. The deubiquitinase ubiquitin-specific peptidase 20 (USP20) suppresses NF-{kappa}B activation in vascular smooth muscle cells (SMCs) and attenuates atherosclerosis. Phosphorylation of USP20 at Ser334 increases NF-{kappa}B signaling in SMCs. However, the role of USP20 in endothelial cells (ECs) remains undefined. We therefore tested whether USP20 activity diminishes NF-{kappa}B signaling in ECs and thereby diminishes angiogenesis. Cytokine-induced NF-{kappa}B activity was elevated in primary ECs isolated from Usp20-/- mice as compared with ECs from wild-type (WT) mice. Concordantly, cytokine-induced NF-{kappa}B activity was elevated in mouse coronary ECs (MCECs) expressing dominant-negative USP20 (USP20-DN) or phospho-mimetic USP20 (USP20-S334D), but blunted in MCECs expressing WT USP20 (USP20-WT) or phospho-resistant USP20 (USP20-S334A). MCEC migration and spheroid sprouting/angiogenesis were increased with overexpression of USP20-DN or USP20-S334D, but decreased with overexpression of USP20-WT or USP20-S334A. Angiogenesis assessed by the aortic ring assay was significantly increased in Usp20-/- aortas and suppressed by TPCA-1, an inhibitor of NF-{kappa}B signaling. Angiogenesis was augmented in Usp20-S334D aortic rings but reduced in Usp20-S334A aortic rings. By screening known angiogenic factors, we identified matrix metalloproteinase 3 (MMP-3), a transcriptional target of NF-{kappa}B, as a gene that is also regulated by USP20 expression. Inhibiting MMP-3 reduced angiogenic sprouting in the Usp20-/- mouse aortic rings. We conclude that USP20 expression inversely correlates with the extent of angiogenesis, and that inhibiting USP20 Ser334 phosphorylation could be a useful strategy to constrain inflammation-driven angiogenesis in pathological conditions like solid tumor malignancies and atherosclerosis.

cancer biology↗

bioRxiv2019

Disulfide disruption reverses mucus dysfunction in allergic airway disease

Airway mucus is essential for healthy lung defense1, but excessive mucus in asthma obstructs airflow, leading to severe and potentially fatal outcomes2-5. Current asthma therapies reduce allergic inflammation and relax airway smooth muscle, but treatments are often inadequate due to their minimal effects on mucus obstruction6,7. The lack of efficacious mucus-targeted treatments stems from a poor understanding of healthy mucus function and pathological mucus dysfunction at a molecular level. The chief macromolecules in mucus, polymeric mucins, are massive glycoproteins whose sizes and biophysical properties are dictated in part by covalent disulfide bonds that link mucin molecules into assemblies of 10 or more subunits8. Once secreted, mucin glycopolymers can aggregate to form plugs that block airflow. Here we show that reducing mucin disulfide bonds depolymerizes mucus in human asthma and reverses pathological effects of mucus hypersecretion in a mouse allergic asthma model. In mice challenged with a fungal allergen, inhaled mucolytic treatment acutely loosened mucus mesh, enhanced mucociliary clearance (MCC), and abolished airway hyperreactivity (AHR) to the bronchoprovocative agent methacholine. AHR reversal was directly related to reduced mucus plugging. Furthermore, protection in mucolytic treated mice was identical to prevention observed in mice lacking Muc5ac, the polymeric mucin required for allergic AHR in murine models9. These findings establish grounds for developing novel fast-acting agents to treat mucus hypersecretion in asthma10,11. Efficacious mucolytic therapies could be used to directly improve airflow, help resolve inflammation, and enhance the effects of inhaled treatments for asthma and other respiratory conditions11,12.

physiology↗