Functional Genomic Analysis of Type II IL-1β Decoy Receptor: Potential for Gene Therapy in Human Arthritis and Inflammation

Abstract

Gene expression arrays show that human epithelial cells and human arthritis-affected cartilage lack detectable amounts of mRNA for IL-1 antagonizing molecules: IL-1Ra and IL-1RII, but constitutively express IL-1. Functional genomic analysis was performed by reconstituting human IL-1RII expression in various IL-1RII-deficient cell types to examine its antagonist role using gene therapy approaches. Adenovirus-expressing IL-1RII when transduced into human and bovine chondrocytes, human and rabbit synovial cells, human epithelial cells, and rodent fibroblasts expressed membrane IL-1RII and spontaneously released functional soluble IL-1RII. The IL-1RII+ (but not IL-1RII−) cells were resistant to IL-1β-induced, NO, PGE2, IL-6, and IL-8 production or decreased proteoglycan synthesis. IL-1RII inhibited the function of IL-1 in chondrocytes and IL-1- and TNF-α-induced inflammatory mediators in human synovial and epithelial cells. IL-1RII+ chondrocytes were more resistant to induction of NO and PGE2 by IL-1β compared with IL-1RII− cells incubated with a 10-fold (weight) excess of soluble type II IL-1R (sIL-1RII) protein. In cocultures, IL-1RII+ synovial cells released sIL-1RII, which in a paracrine fashion protected chondrocytes from the effects of IL-1β. Furthermore, IL-1RII+ (but not IL-1RII−) chondrocytes when transplanted onto human osteoarthritis-affected cartilage in vitro, which showed spontaneous release of sIL-1RII for 20 days, inhibited the spontaneous production of NO and PGE2 in cartilage in ex vivo. In summary, reconstitution of IL-1RII in IL-1RII− cells using gene therapy approaches significantly protects cells against the autocrine and paracrine effects of IL-1 at the signaling and transcriptional levels.

Osteoarthritis gene therapy

“…[110][111][112] These investigators recovered human articular cartilage from knee joints at the time of joint replacement surgery for OA, and measured the ex vivo synthesis of NO, MMPs, prostaglandin E 2 (PGE 2 ), IL-6, IL-1Ra and the type II soluble IL-1 receptor (sIL-1RII). Compared to normal cartilage, the cartilage recovered from diseased joints synthesized elevated amounts of NO, MMPs, IL-6 and PGE 2 in an IL-1-dependent manner.…”

“…Moreover, IL-1 appears to be the major driver of pathophysiological disturbances in the articular cartilage of joints with OA. [110][111][112] Increased expression of the type I IL-1 receptor may render chondrocytes particularly sensitive to the effects of IL-1 in OA. 113 These conclusions agree very well with the observations of Melchiorri et al, 114 who used immunohistochemistry to detect the expression of IL-1b by human synovium and cartilage recovered from OA knees.…”

Transamidation by Transglutaminase 2 Transforms S100A11 Calgranulin into a Procatabolic Cytokine for Chondrocytes

“…Inhibition of IL-1␤ only partially inhibits experimental OA (13)(14)(15), and thus the respective roles of other inflammatory mediators in OA remain to be defined. S100/calgranulins are a family of over 20 proteins of ϳ10 -12 kDa that share conserved calcium-binding EF-hand domains and associate noncovalently as homodimers and heterodimers (16).…”

Gene Therapy for Human Osteoarthritis

“…Inhibition of catabolic pathways has been observed when expressing inhibitors of matrixdegrading enzymes (tissue inhibitor of MMPs, i.e. TIMP) (Kafienah et al, 2003), inhibitors of proinflammatory cytokines (IL-1Ra; the soluble receptors sIL-1R or sTNFR) (Attur et al, 2002;Baragi et al, 1995;Gouze, J. N. et al, 2003;Haupt et al, 2005;Roessler et al, 1995;Zhang, H. G. et al, 2000;Zhang, X. et al, 2006), and chondroprotective cytokines (IL-4; IL-10) (Kim, S. H. et al, 2001;Zhang, X. et al, 2006). Activation of anabolic processes has been noted by single or combined administration of components of the cartilage matrix or of the enzymes that synthesize them (Dharmavaram et al, 1999;Venkatesan et al, 2004), of growth factors and receptors (insulin-like growth factor I, i.e.…”