MSc Federal University of Rio de Janeiro Rio de Janeiro, Rio de Janeiro, Brazil
Disclosure(s):
Letícia Carvalho, MSc: No financial relationships to disclose
Introduction/Rationale: Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Vascular alterations play a central role, promoting endothelial barrier disruption and neuroinflammation, key features of sepsis-associated encephalopathy. Activated endothelial cells release ATP, which acts as an alarmin by activating purinergic receptors or being degraded by ectonucleotidases like CD39, thereby modulating ATP-driven inflammatory responses. This study aimed to evaluate the role of CD39 in sepsis-associated cerebrovascular alterations.
Methods: In vitro, mouse brain capillary endothelial cells (bEnd.3) were stimulated with LPS (100 or 1000 ng/mL) for 8 h or 24 h. To assess the role of CD39, the enzyme inhibitors POM-1 (10 µM) and AR67156 (100 µM) were used 30 min before LPS stimulation. In vivo, sepsis was induced by cecal ligation and puncture (CLP) in WT and CD39 -/- C57BL/6 mice. Mice were euthanized 24 h after sepsis induction, and brain structures and serum were collected. Brain intravital microscopy experiments were also performed to evaluate leukocyte adhesion in cerebral microcirculation, and coagulation was determined by recalcification tests.
Results: LPS stimulation reduced CD39 protein expression and enzymatic activity in bEnd.3 without affecting purinergic receptor protein and mRNA levels. CD39 inhibition increased LPS-induced mRNA expression of endothelial markers (ICAM-1, VCAM-1, CXCL-1). Quantification of CXCL-1 by ELISA and immunocytochemical analyses for VCAM and ICAM also showed similar results. Septic CD39 -/- mice showed higher mRNA expression of ICAM-1 and CXCL-1 in the brain as well as elevated levels of CXCL-1 protein in the brain and serum compared to septic WT mice. Septic CD39 -/- mice showed increased leukocyte adhesion and a more procoagulant profile.
Conclusion: These findings indicate that the enzyme CD39 plays a protective role in modulating endothelial activation, leukocyte adhesion, and cerebral microvascular inflammation during sepsis.
