title: Co-expression of insulin-like growth factor-1 and interleukin-4 in an in vitro inflammatory model.
abstract: The ailment osteoarthritis (OA) has two aspects - inflammation and cartilage degradation - where combined transgene expression may offer an effective gene therapy. Our present study focuses on the co-expression of interleukin-4 (IL-4) and insulin-like-growth factor-1 (IGF-1), which specifically target inflammation and cartilage repair, respectively. In this study, we analyze the expression of IGF-1 and IL-4 from a single plasmid vector, where each gene is expressed through an independent promoter and enhancer sequence. Regenerative and anti-inflammatory effects of IGF-1 alone and of both IGF-1 and IL-4 were analyzed in an in vitro chondrocyte inflammatory model. Co-expression of both transgenes in primary chondrocytes was ascertained by immunoassays. Following stimulation with IL-1beta and TNFalpha, pro-inflammatory mediators as well as IGF-binding proteins were down-regulated more effectively in the presence of both genes to levels comparable to the non-stimulated control. Further, cartilage regeneration proteins type II collagen and proteoglycans were up-regulated in stimulated cells transfected with IGF-1 alone and in combination with IL-4. The co-expression of IGF-1 and IL-4 shows that both transgenes complement each other by effectively triggering cartilage regeneration and reducing inflammation. Use of combinatorial transgene expression offers a promising avenue in the area of gene therapy in OA.
authors.affiliation: Institute of Immunology and Molecular Biology, Freie Universität Berlin, Philippstrasse 13, 10115 Berlin, Germany.
authors.forename: Kizzie
authors.initials: K
authors.lastname: Manning
authors.forename: P Sivaramakrishna
authors.initials: PS
authors.lastname: Rachakonda
authors.forename: Muhammad Farooq
authors.initials: MF
authors.lastname: Rai
authors.forename: Michael F G
authors.initials: MF
authors.lastname: Schmidt
mesh_terms: D053674:Aggrecans / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019902:Chondrocytes / Q000201:enzymology / Q000473:pathology; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D004285:Dogs; D015536:Down-Regulation / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000201:enzymology / Q000378:metabolism*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism*; D064235:Matrilin Proteins; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D018448:Models, Immunological; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: D053674:Aggrecans; D024043:Collagen Type II; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D018969:Insulin-Like Growth Factor Binding Proteins; D064235:Matrilin Proteins; D009573:Nitrites; D012333:RNA, Messenger; D015847:Interleukin-4; D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I; D052247:Nitric Oxide Synthase Type II; D017526:Receptor, IGF Type 1; D020782:Matrix Metalloproteinases