Protein disulfide isomerase externalization in endothelial cells follows classical and unconventional routes

Author(s)

Araujo, Thais L. S. ; Zeidlera, Julianna D. ; Oliveira, Percillia V. S. ; Dias, Matheus H. ; Armelin, Hugo A. ; Laurindo, Francisco R. M.

• Document type: Journal article
• Source: Free Radical Biology and Medicine; v. 103, p. 199-208, FEB 2017.
• Web of Science Citations: 11

Abstract

Extracellular protein disulfide isomerase (PDIA1) pool mediates thrombosis and vascular remodeling, however its externalization mechanisms remain unclear. We performed systematic pharmacological screening of secretory pathways affecting extracellular PDIA1 in endothelial cells (EC). We identified cell-surface (csPDIA1) and secreted non-particulated PDIA1 pools in EC. Such Golgi bypass also occurred for secreted PDIA1 in EC at baseline or after PMA, thrombin or ATP stimulation. Inhibitors of Type I, II and III unconventional routes, secretory lysosomes and recycling endosomes, including syntaxin-12 deletion, did not impair EC PDIA1 externalization This suggests predominantly Golgi-independent unconventional secretory route(s), which were GRASP55-independent. Also, these data reinforce a vesicular-type traffic for PDIA1. We further showed that PDIA1 traffic is ATP-independent, while actin or tubulin cytoskeletal disruption markedly increased EC PDIA1 secretion. Clathrin inhibition enhanced extracellular soluble PDIA1, suggesting dynamic cycling. Externalized PDIA1 represents <2% of intracellular PDIA1. PDIA1 was robustly secreted by physiological levels of arterial laminar shear in EC and supported alpha 5 integrin thiol oxidation. Such results help clarify signaling and homeostatic mechanisms involved in multiple (patho)physiological extracellular PDIA1 functions. (AU)

• FAPESP's process: 14/20595-1 - Protein Disulfide Isomerase (PDI) as a marker of risk for thrombosis and/or accelerated progression of atherosclerosis in patients with familial hipercholesterolemia and in experimental model
• Grantee: Percíllia Victória Santos de Oliveira
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 12/02372-0 - Mechanisms and redox effects of epi/pericellular protein disulfide isomerase
• Grantee: Thaís Larissa Araujo de Oliveira Silva
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/54764-6 - Regulation of redox homeostasis and integrated stress response by Protein Disulfide Isomerase (PDI): mechanisms and role in the pathophysiology and therapy of vascular diseases
• Grantee: Francisco Rafael Martins Laurindo
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 13/07937-8 - Redoxome - Redox Processes in Biomedicine
• Grantee: Ohara Augusto
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC