title: Regulation of H19 and its encoded microRNA-675 in osteoarthritis and under anabolic and catabolic in vitro conditions.
abstract: Cartilage degeneration in the course of osteoarthritis (OA) is associated with an alteration in chondrocyte metabolism. In order to identify molecules representing putative key regulators for diagnosis and therapeutic intervention, we analyzed gene expression and microRNA (miR) levels in OA and normal knee cartilage using a customized cartilage cDNA array and quantitative RT-PCR. Among newly identified candidate molecules, H19, IGF2, and ITM2A were significantly elevated in OA compared to normal cartilage. H19 is an imprinted maternally expressed gene influencing IGF2 expression, whose transcript is a long noncoding (lnc) RNA of unknown biological function harboring the miR-675. H19 and IGF2 mRNA levels did not correlate significantly within cartilage samples suggesting that deregulation by imprinting effects are unlikely. A significant correlation was, however, observed for H19, COL2A1, and miR-675 expression levels in OA tissue, and functional regulation of these candidate molecules was assessed under anabolic and catabolic conditions. Culture of chondrocytes under hypoxic signaling showed co-upregulation of H19, COL2A1, and miRNA-675 levels in close correlation. Proinflammatory cytokines IL-1β and TNF-α downregulated COL2A1, H19, and miR-675 significantly without close statistical correlation. In conclusion, this is the first report demonstrating deregulation of an lncRNA and its encoded miR in the context of OA-affected cartilage. Stress-induced regulation of H19 expression by hypoxic signaling and inflammation suggests that lncRNA H19 acts as a metabolic correlate in cartilage and cultured chondrocytes, while the miR-675 may indirectly influence COL2A1 levels. H19 may not only be an attractive marker for cell anabolism but also a potential target to stimulate cartilage recovery.
authors.affiliation: Research Centre for Experimental Orthopaedics, Orthopaedic University Hospital Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany. steck@web.de
authors.forename: Eric
authors.initials: E
authors.lastname: Steck
authors.forename: Stephane
authors.initials: S
authors.lastname: Boeuf
authors.forename: Jessica
authors.initials: J
authors.lastname: Gabler
authors.forename: Nadine
authors.initials: N
authors.lastname: Werth
authors.forename: Philipp
authors.initials: P
authors.lastname: Schnatzer
authors.forename: Solvig
authors.initials: S
authors.lastname: Diederichs
authors.forename: Wiltrud
authors.initials: W
authors.lastname: Richter
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015687:Cell Hypoxia; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D000074289:High-Temperature Requirement A Serine Peptidase 1; D006801:Humans; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000378:metabolism* / Q000473:pathology; D062085:RNA, Long Noncoding / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome; D055815:Young Adult
chemical_list: C499177:COL2A1 protein, human; D024043:Collagen Type II; C094335:H19 long non-coding RNA; C035170:IGF2 protein, human; C485527:ITM2A protein, human; C548379:MIRN675 microRNA, human; D008565:Membrane Proteins; D035683:MicroRNAs; D062085:RNA, Long Noncoding; D007335:Insulin-Like Growth Factor II; D000074289:High-Temperature Requirement A Serine Peptidase 1; C474012:HTRA1 protein, human; D012697:Serine Endopeptidases