title: Vitamin D₃ metabolites enhance the NLRP3-dependent secretion of IL-1β from human THP-1 monocytic cells.
abstract: Vitamin D3 has emerged as an important regulator of the immune system. With metabolic enzymes for vitamin D3 activation and vitamin D receptors (VDR) now identified in a variety of immune cells, the active vitamin D3 metabolite 1,25(OH)2D3, is thought to possess immunomodulatory properties. We examined whether 1,25(OH)2D3 might also enhance the NLRP3-dependent release of mature IL-1β from macrophages. PMA-differentiated THP-1 cells were stimulated with vitamin D3 metabolites and assessed for CYP27, CYP24, NLRP3, ASC, pro-caspase-1 expression by western blot and real-time qPCR as well as inflammasome activation with pro-inflammatory cytokine IL-1β release measured by ELISA. Exposure to 1,25(OH)2D3 had no effect on the basal expression levels of VDR; however, CYP27A1 transcript was suppressed and CYP24A1 transcript was substantively elevated. Both 1,25(OH)2D3 - and 25(OH)D3 induced IL-1β release from THP-1 cells, and these effects were blocked with application of the caspase-1 inhibitor YVAD and the NLRP3 inhibitors glyburide and Bay 11-7082. Interestingly, 1,25 (OH)2D3 exposure reduced NLRP3 protein expression but had no effect on ASC or pro-caspase-1 protein levels. The increase in mature IL-1β elicited by 1,25(OH)2D3 was modest compared to that found for ATP or C. difficile toxins. However, co-treatment of THP-1 cells with ATP and 1,25(OH)2D3 resulted in more IL-1β secretion than ATP or 1,25(OH)2D3 alone.
authors: Department of Biochemistry & Molecular Biology, University of Calgary, 3280, Hospital Drive, NW, Calgary, AB, T2N 4Z6, Canada.
authors: Sarah E
authors: SE
authors: Tulk
authors: Kuo-Chieh
authors: KC
authors: Liao
authors: Daniel A
authors: DA
authors: Muruve
authors: Yan
authors: Y
authors: Li
authors: Paul L
authors: PL
authors: Beck
authors: Justin A
authors: JA
authors: MacDonald
mesh_terms: D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D020170:Caspase 1 / Q000378:metabolism; D061945:Caspase Inhibitors / Q000494:pharmacology; D002762:Cholecalciferol / Q000737:chemistry / Q000378:metabolism*; D053493:Cholestanetriol 26-Monooxygenase / Q000378:metabolism; D005905:Glyburide / Q000494:pharmacology; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; D009570:Nitriles / Q000494:pharmacology; D018167:Receptors, Calcitriol / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology
chemical_list: C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; D000590:Amino Acid Chloromethyl Ketones; D002352:Carrier Proteins; D061945:Caspase Inhibitors; D053583:Interleukin-1beta; C098738:N-acetyl-tyrosyl-valyl-alanyl-aspartyl chloromethyl ketone; D000071199:NLR Family, Pyrin Domain-Containing 3 Protein; C453881:NLRP3 protein, human; D009570:Nitriles; D018167:Receptors, Calcitriol; D013450:Sulfones; D002762:Cholecalciferol; C506831:CYP27A1 protein, human; D053493:Cholestanetriol 26-Monooxygenase; D020170:Caspase 1; D005905:Glyburide
keywords: 1; 25-DIHYDROXY-VITAMIN D3; INNATE IMMUNITY; INTERLEUKIN-1β; MACROPHAGE; NLR; NOD-LIKE RECEPTOR; VDR