Specific increase in caspase-1 activity and secretion of IL-1 family cytokines: a putative link between mevalonate kinase deficiency and inflammation

• Published in: European cytokine network Vol. 20; no. 3; p. 101
• Main Authors: Normand, Sylvain, Massonnet, Benoit, Delwail, Adriana, Favot, Laure, Cuisset, Laurence, Grateau, Gilles, Morel, Franck, Silvain, Christine, Lecron, Jean-Claude
• Format: Journal Article
• Language: English
• Published: France 01.09.2009
• Subjects: Animals; Caspase 1 - metabolism; Disease Models, Animal; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors - therapeutic use; Inflammation - complications; Inflammation - enzymology; Inflammation - immunology; Interleukin-1 - secretion; Mevalonate Kinase Deficiency - complications; Mevalonate Kinase Deficiency - drug therapy; Mevalonate Kinase Deficiency - enzymology; Mevalonate Kinase Deficiency - immunology
• ISSN: 1952-4005
• DOI: 10.1684/ecn.2009.0163

The mevalonate kinase deficiency (MKD), including hyperimmunoglobulinemia D periodic fever syndrome (HIDS) and the more severe mevalonic aciduria are rare, autosomal recessive, autoinflammatory diseases belonging to the hereditary periodic fever (HPF) family. Other members include: familial mediterranean fever (FMF), the cryopyrin-associated periodic syndromes (CAPS) and TNFR-associated periodic syndromes (TRAPS). MKD is caused by mutations in the gene encoding mevalonate kinase (MK), an enzyme of the cholesterol pathway, leading to its inactivation. The molecular mechanisms linking MKD and abnormalities of isoprenoid biosynthesis to cytokine production and inflammation have yet to be fully elucidated. Statins, which are extensively prescribed for lowering cholesterol, are potent inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase, the enzyme directly upstream of MK. In this review, we discuss recent reports demonstrating that in vitro inhibition of the mevalonate pathway by statins specifically increases the production, by activated monocytes, of cytokines of the IL-1 family, by enhancing caspase-1 activity, the enzyme responsible for IL-1beta and IL-18 maturation. The molecular mechanisms involve geranylgeranylation and the enhancement of the activity of G proteins such as Rac-1. Interestingly, activated fibroblasts from MKD patients secrete more IL-1beta than fibroblasts from healthy donors. Taken together, these data highlight the specific enhancement of the IL-1 family of cytokines, the maturation of which is caspase-1-dependent in MKD. Finally, the spectacular decrease in febrile attacks in patients with severe HIDS under IL-1 receptor antagonist (anakinra) treatment, reinforces this hypothesis. Deregulated caspase-1 activation could be responsible for the inflammatory component of MKD, thereby mechanistically linking MKD to FMF and CAPS through cytokines of the IL-1 family.