title: Regulation of macrophage activation and septic shock susceptibility via p21(WAF1/CIP1).
abstract: p21 is a cell-cycle inhibitor that is also known to suppress autoimmunity. Here, we provide evidence of a novel role for p21 as an inhibitor of macrophage activation. LPS stimulation of p21-deficient peritoneal macrophages induced increased activation compared with controls, with elevated production of proinflammatory mediators such as TNF-alpha and IL-1beta. The enhanced activity of LPS-stimulated p21-deficient macrophages correlated with increased activity of the transcription factor NF-kappaB. LPS stimulation of p21-deficient macrophages led to increased IkappaBalpha kinase activity, and increased IkappaBalpha phosphorylation and degradation, resulting in elevated NF-kappaB activity. The effect of p21 in macrophage activation was independent of its cell-cycle inhibitory role. p21(-/-) mice showed greater sensitivity to LPS-induced septic shock than did WT mice, indicating that p21 contributes to maintenance of a balanced response to inflammatory stimuli and suggesting biological significance for the role of p21 in macrophage activation. Our findings project a role for p21 in the control of NF-kappaB-associated inflammation, and suggest that therapeutic modulation of p21 expression could be beneficial in inflammation-associated diseases.
authors.affiliation: Department of Immunology and Oncology, Centro Nacional de Biotecnología/CSIC, Madrid, Spain.
authors.forename: Marianna
authors.initials: M
authors.lastname: Trakala
authors.forename: Cristina F
authors.initials: CF
authors.lastname: Arias
authors.forename: María I
authors.initials: MI
authors.lastname: García
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Moreno-Ortiz
authors.forename: Katerina
authors.initials: K
authors.lastname: Tsilingiri
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Fernández
authors.forename: Mario
authors.initials: M
authors.lastname: Mellado
authors.forename: María T
authors.initials: MT
authors.lastname: Díaz-Meco
authors.forename: Jorge
authors.initials: J
authors.lastname: Moscat
authors.forename: Manuel
authors.initials: M
authors.lastname: Serrano
authors.forename: Carlos
authors.initials: C
authors.lastname: Martínez-A
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Balomenos
mesh_terms: D000818:Animals; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004198:Disease Susceptibility / Q000276:immunology / Q000378:metabolism; D005260:Female; D051550:I-kappa B Kinase / Q000276:immunology / Q000378:metabolism; D053583:Interleukin-1beta / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000187:drug effects / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D016328:NF-kappa B / Q000276:immunology / Q000378:metabolism; D012772:Shock, Septic / Q000276:immunology* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000378:metabolism
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D051550:I-kappa B Kinase