Complexity of IL-1β induced gene expression pattern in human articular chondrocytes

Abstract

The mRNA fingerprinting technique, differential display reverse transcription polymerase chain (DDRT-PCR), was used to detect changes in the overall pattern of gene expression in human articular knee chondrocytes-induced by interleukin-1 beta (IL-1 beta), the prototypical inducer of catabolic responses in degenerate joint diseases. One hundred different primer combinations generated approximately 10,000 different PCR fragments for IL-1 beta treated, as well as for untreated human chondrocytes, cultivated in alginate beads. This represented 53% of all expressed chondrocyte genes as based on statistical considerations. Side by side comparisons of differential display patterns originating from two different donor tissues yielded 44 reproducibly, differentially-displayed cDNA fragments, which were subcloned and sequenced. Sequence homology searches revealed sequence identities to the human necrosis factor alpha (TNF-alpha) and IL-1 regulated gene TSG-6, fibronectin, osteopontin, calnexin, and the DNA repair enzyme ERCC5. The differential expression was confirmed with Northern and quantitative PCR analyses. The known function of these genes and their known IL-1 responsiveness indicate that the employed model system reflects the pleiotropic effects of IL-1 on the overall gene expression in human articular chondrocytes and identifies genes involved in very different biochemical pathways. Twenty-seven cDNAs lacked sequence homologies to known genes and may represent novel genes.

IL-1 Up-Regulates Osteopontin Expression in Experimental Crescentic Glomerulonephritis in the Rat

“…The ability of IL-1 to up-regulate OPN expression in renal epithelial cells is consistent with previous studies reporting that IL-1 increases OPN mRNA expression by cultured chrondocytes and osteoblasts. 24,25 However, it should be noted that regulation of OPN gene expression varies greatly between different cell types. For example, IL-1 failed to increase OPN gene expression in cultured rat mesangial cells.…”

“…First, IL-1 has been shown to up-regulate OPN gene expression in chrondocytes and osteoblasts. 24,25 Second, blocking IL-1 activity inhibits macrophage infiltration and renal injury in rat anti-GBM disease. 26,27 Therefore, the current study examined whether IL-1 is an important inducer of OPN expression in experimental crescentic glomerulonephritis.…”

TSG-6: a multifunctional protein associated with inflammation

“…TSG-6 expression can be induced in cultured articular synoviocytes by IL-1 and TNF (Wisniewski et al, 1993) and in articular chondrocytes by IL-1, TNF, PDGF and TGFβ (Maier et al, 1996;Margerie et al, 1997). There is also good evidence that TSG-6 is produced locally in the synovium and cartilage of OA and RA joints .…”

A Novel Allelic Variant of the Human TSG-6 Gene Encoding an Amino Acid Difference in the CUB Module

“…For example, TSG-6 expression (mRNA and protein) is induced in human chondrocytes, from macroscopically normal cartilage, by interleukin-1␤ (IL-1␤), tumor necrosis factor, and transforming growth factor-␤1 (10). An mRNA fingerprinting technique identified TSG-6 as one of the major species to be up-regulated (ϳ6-fold) in response to IL-1␤ in chondrocytes obtained from OA patients undergoing joint surgery (11).…”