title: Role of nucleotide-binding oligomerization domain 1 (NOD1) in pericyte-mediated vascular inflammation.
abstract: We have recently described the response of human brain pericytes to lipopolysaccharide (LPS) through toll-like receptor 4 (TLR4). However, Gram-negative pathogen-associated molecular patterns include not only LPS but also peptidoglycan (PGN). Given that the presence of co-purified PGN in the LPS preparation previously used could not be ruled out, we decided to analyse the expression of the intracellular PGN receptors NOD1 and NOD2 in HBP and compare the responses to their cognate agonists and ultrapure LPS. Our findings show for the first time that NOD1 is expressed in pericytes, whereas NOD2 expression is barely detectable. The NOD1 agonist C12-iE-DAP induced IL6 and IL8 gene expression by pericytes as well as release of cytokines into culture supernatant. Moreover, we demonstrated the synergistic effects of NOD1 and TLR4 agonists on the induction of IL8. Using NOD1 silencing in HBP, we showed a requirement for C12-iE-DAP-dependent signalling. Finally, we could discriminate NOD1 and TLR4 pathways in pericytes by pharmacological targeting of RIPK2, a kinase involved in NOD1 but not in TLR4 signalling cascade. p38 MAPK and NF-κB appear to be downstream mediators in the NOD1 pathway. In summary, these results indicate that pericytes can sense Gram-negative bacterial products by both NOD1 and TLR4 receptors, acting through distinct pathways. This provides new insight about how brain pericytes participate in the inflammatory response and may have implications for disease management.
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Rocío
authors.initials: R
authors.lastname: Navarro
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Delgado-Wicke
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Natalia
authors.initials: N
authors.lastname: Nuñez-Prado
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Compte
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Blanco-Toribio
authors.affiliation: Department of Pathology and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Nuñez
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.|Immunotherapy and Cell Engineering Laboratory, Department of Engineering, Aarhus University, Aarhus, Denmark.
authors.forename: Luis
authors.initials: L
authors.lastname: Álvarez-Vallina
authors.affiliation: Molecular Immunology Unit, Hospital Universitario Puerta de Hierro Majadahonda, Majadahonda, Madrid, Spain.
authors.forename: Laura
authors.identifier: http://orcid.org/0000-0002-3119-3218
authors.initials: L
authors.lastname: Sanz
mesh_terms: D001921:Brain / Q000098:blood supply / Q000166:cytology / Q000378:metabolism; D002536:Cerebral Arteries / Q000166:cytology / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation; D015850:Interleukin-6 / Q000096:biosynthesis / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D053474:Nod1 Signaling Adaptor Protein / Q000235:genetics* / Q000378:metabolism; D053473:Nod2 Signaling Adaptor Protein / Q000172:deficiency / Q000235:genetics; D010457:Peptidoglycan / Q000494:pharmacology*; D020286:Pericytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D061251:Primary Cell Culture; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics* / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: C508606:CXCL8 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; C119067:NOD1 protein, human; C429018:NOD2 protein, human; D053474:Nod1 Signaling Adaptor Protein; D053473:Nod2 Signaling Adaptor Protein; D010457:Peptidoglycan; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C506253:RIPK2 protein, human; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D048051:p38 Mitogen-Activated Protein Kinases
keywords: NOD1; TLR4; inflammation; lipopolysaccharide; peptidoglycan; pericyte; vascular biology