Protective role of Cav-1 in pneumolysin-induced endothelial barrier dysfunction

Robert K. Batori, Feng Chen, Zsuzsanna Bordan, Stephen Haigh, Yunchao Su, Alexander D. Verin, Scott A. Barman, David W. Stepp, Trinad Chakraborty, Rudolf Lucas, David J.R. Fulton

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3 Scopus citations


Pneumolysin (PLY) is a bacterial pore forming toxin and primary virulence factor of Streptococcus pneumonia, a major cause of pneumonia. PLY binds cholesterol-rich domains of the endothelial cell (EC) plasma membrane resulting in pore assembly and increased intracellular (IC) Ca2+ levels that compromise endothelial barrier integrity. Caveolae are specialized plasmalemma microdomains of ECs enriched in cholesterol. We hypothesized that the abundance of cholesterol-rich domains in EC plasma membranes confers cellular susceptibility to PLY. Contrary to this hypothesis, we found increased PLY-induced IC Ca2+ following membrane cholesterol depletion. Caveolin-1 (Cav-1) is an essential structural protein of caveolae and its regulation by cholesterol levels suggested a possible role in EC barrier function. Indeed, Cav-1 and its scaffolding domain peptide protected the endothelial barrier from PLY-induced disruption. In loss of function experiments, Cav-1 was knocked-out using CRISPR-Cas9 or silenced in human lung microvascular ECs. Loss of Cav-1 significantly enhanced the ability of PLY to disrupt endothelial barrier integrity. Rescue experiments with re-expression of Cav-1 or its scaffolding domain peptide protected the EC barrier against PLY-induced barrier disruption. Dynamin-2 (DNM2) is known to regulate caveolar membrane endocytosis. Inhibition of endocytosis, with dynamin inhibitors or siDNM2 amplified PLY induced EC barrier dysfunction. These results suggest that Cav-1 protects the endothelial barrier against PLY by promoting endocytosis of damaged membrane, thus reducing calcium entry and PLY-dependent signaling.

Original languageEnglish (US)
Article number945656
Pages (from-to)945656
JournalFrontiers in immunology
StatePublished - Jul 27 2022


  • Bacterial Proteins/genetics
  • Caveolin 1/genetics
  • Cholesterol/metabolism
  • Endothelium, Vascular/metabolism
  • Humans
  • Lung/blood supply
  • Microvessels/metabolism
  • Pneumonia, Pneumococcal/genetics
  • Pneumonia/genetics
  • Streptococcus pneumoniae/metabolism
  • Streptolysins/genetics
  • Vascular Diseases/genetics


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