p58(IPK) suppresses NLRP3 inflammasome activation and IL-1β production via inhibition of PKR in macrophages.
The NLRP3 inflammasome activation is a key signaling event for activation and secretion of pro-inflammatory cytokines such as IL-1β from macrophages. p58(IPK) is a molecular chaperone that regulates protein homeostasis through inhibiting eIF-2α kinases including double-stranded RNA-dependent protein kinase (PKR), which has been recently implicated in inflammasome activation. Herein we investigate the role of p58(IPK) in TLR4 signaling and inflammasome activation in macrophages. Primary bone marrow-derived macrophages (BMDM) was isolated from p58(IPK) knockout (KO) and wildtype (WT) mice and treated with lipopolysaccharide (LPS) and ATP to activate TLR4 signaling and stimulate inflammasome activation. Compared to WT macrophages, p58(IPK) deficient cells demonstrated significantly stronger activation of PKR, NF-κB, and JNK and higher expression of pro-inflammatory genes TNF-α and IL-1β. Coincidently, p58(IPK) deletion intensified NLRP3-inflammasome activation indicated by enhanced caspase 1 cleavage and increased IL-1β maturation and secretion. Pretreatment with specific PKR inhibitor or overexpression of p58(IPK) largely abolished the changes in inflammasome activation and IL-1β secretion in p58(IPK) null macrophages. Furthermore, immunoprecipitation assay confirmed the binding of p58(IPK) with PKR, but not other TLR4 downstream signaling molecules. Collectively, these results suggest a novel and crucial role of p58(IPK) in regulation of inflammasome activation and IL-1β secretion in macrophages.
Department of Ophthalmology/Ross Eye Institute, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.|SUNY Eye Institute, the State University of New York, Buffalo, NY 14214, USA.
Evgenii
E
Boriushkin
Department of Ophthalmology/Ross Eye Institute, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.|SUNY Eye Institute, the State University of New York, Buffalo, NY 14214, USA.
Joshua J
JJ
Wang
Department of Ophthalmology/Ross Eye Institute, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.|SUNY Eye Institute, the State University of New York, Buffalo, NY 14214, USA.
Junhua
J
Li
Department of Ophthalmology/Ross Eye Institute, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.|SUNY Eye Institute, the State University of New York, Buffalo, NY 14214, USA.
Maulasri
M
Bhatta
Department of Ophthalmology/Ross Eye Institute, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.|SUNY Eye Institute, the State University of New York, Buffalo, NY 14214, USA.|Department of Biochemistry, University at Buffalo, the State University of New York, Buffalo, NY 14214, USA.
Sarah X
SX
Zhang
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002478:Cells, Cultured; D055786:Gene Knockout Techniques; D050956:HSP40 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000166:cytology / Q000378:metabolism*; D051379:Mice; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein / Q000378:metabolism*; D011485:Protein Binding; D015398:Signal Transduction; D019892:eIF-2 Kinase / Q000378:metabolism*
C500846:Dnajc3 protein, mouse; D050956:HSP40 Heat-Shock Proteins; C587672:IL1B protein, mouse; D053583:Interleukin-1beta; D008070:Lipopolysaccharides; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C492716:Nlrp3 protein, mouse; D000255:Adenosine Triphosphate; D019892:eIF-2 Kinase; C000605978:protein kinase R, mouse