Extracellular Histones Activate Endothelial NLRP3 Inflammasome and are Associated with a Severe Sepsis Phenotype.

Fecha de publicación: 25/07/2022 Fecha Ahead of Print: 25/07/2022

Autores de INCLIVA

• Rebeca Osca Verdegal

  Autor

• Daniel Bernardo Perez Cremades

  Autor

• 

  Susana Novella Del Campo

  Autor

• 

  Carlos Hermenegildo Caudevilla

  Autor

• 

  Federico Vicente Pallardo Calatayud

  Autor

• 

  Jose Luis Garcia Gimenez

  Autor

Participantes ajenos a INCLIVA

• Beltrán-García J

Grupos y Plataformas de I+D+i

• Grupo de Investigación en Células Endoteliales (LINCE)

  

  Leading Researcher Co-IP

  Susana Novella Del Campo

• Grupo de Investigación en Epigenómica y Epigenética traslacional

  

  Established Researcher

  Jose Luis Garcia Gimenez

• Grupo de Investigación sobre Fisiopatología celular y orgánica del Estrés Oxidativo

  

  Leading Researcher

  Federico Vicente Pallardo Calatayud

Abstract

INTRODUCTION: Circulating extracellular histones acquire relevance as cytotoxic mediators in sepsis. Extracellular histones act as damage-associated molecular patterns (DAMPs), which induce oxidative stress and NLRP3 inflammasome activation. Inflammasome mediates pyroptosis, a programmed cell death mechanism that produces inflammation. Despite evidence for inflammasome activation in immune cells during sepsis, it was unknown whether extracellular histones can produce endothelial inflammasomes activation. METHODS: We used human umbilical vein endothelial cells (HUVEC) to explore the activation of pyroptosis, endothelial function and inflammation by extracellular histones. We evaluated pyroptosis by flow cytometry, caspase-1 activity assay, and gene and protein expression analysis by RT-qPCR and Western blot, respectively. The upstream molecular responses involved in pyroptosis activation by extracellular histones were validated by means of using antioxidant glutathione ethyl ester and NLRP3 inflammasome inhibitors. Finally, using mass spectrometry, we measured circulating histones in blood from critically-ill patients and demonstrated that circulating histone levels correlated with the expression of pyroptosis-related cytokines, the release of endothelial adhesion factors and septic shock severity. RESULTS: We found that extracellular histones mediate the activation of NLRP3 inflammasome and pyroptosis in endothelial cells by contributing to endothelial dysfunction and the dysregulation of the immune response mediated by endothelium. Likewise, we demonstrated how the hyperacetylation of extracellular histones or the use of antioxidants decreased pyroptosis. In addition, we showed that pyroptosis is a feasible process occurring in septic shock patients. DISCUSSION: Circulating histone levels correlated with the expression of pro-inflammatory and pyroptosis-related cytokines, the release of endothelial adhesion factors and septic shock severity. We propose to block histone-mediated pyroptosis as a feasible therapeutic strategy in sepsis.

© 2022 Beltrán-García et al.

Keywords

• NLRP3; endothelium; extracellular histones; histone acetylation; inflammasome; sepsis