title: Insights into osteoarthritis progression revealed by analyses of both knee tibiofemoral compartments.
abstract: OBJECTIVE
  To identify disease relevant genes and pathways associated with knee Osteoarthritis (OA) progression in human subjects using medial and lateral compartment dominant OA knee tissue.
  
  
  METHODS
  Gene expression of knee cartilage was comprehensively assessed for three regions of interest from human medial dominant OA (n = 10) and non-OA (n = 6) specimens. Histology and gene expression were compared for the regions with minimal degeneration, moderate degeneration and significant degeneration. Agilent whole-genome microarray was performed and data were analyzed using Agilent GeneSpring GX11.5. Significant differentially regulated genes were further investigated by Ingenuity Pathway Analysis (IPA) to identify functional categories. To confirm their association with disease severity as opposed to site within the knee, 30 differentially expressed genes, identified by microarray, were analyzed by quantitative reverse-transcription polymerase chain reaction on additional medial (n = 16) and lateral (n = 10) compartment dominant knee OA samples.
  
  
  RESULTS
  A total of 767 genes were differentially expressed ≥ two-fold (P ≤ 0.05) in lesion compared to relatively intact regions. Analysis of these data by IPA predicted biological functions related to an imbalance of anabolism and catabolism of cartilage matrix components. Up-regulated expression of IL11, POSTN, TNFAIP6, and down-regulated expression of CHRDL2, MATN4, SPOCK3, VIT, PDE3B were significantly associated with OA progression and validated in both medial and lateral compartment dominant OA samples.
  
  
  CONCLUSIONS
  Our study provides a strategy for identifying targets whose modification may have the potential to ameliorate pathological alternations and progression of disease in cartilage and to serve as biomarkers for identifying individuals susceptible to progression.
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; National Center for Genome Medicine, Academia Sinica, Taipei, Taiwan; Department of Pathology, Duke University School of Medicine, Durham, NC, USA. Electronic address: cc380@duke.edu.
authors.forename: C-H
authors.initials: CH
authors.lastname: Chou
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; National Center for Genome Medicine, Academia Sinica, Taipei, Taiwan; Graduate Institute of Chinese Medical Science, China Medical University, Taichung, Taiwan; Laboratory for International Alliance, RIKEN Center for Genomic Medicine, Yokohama, Japan. Electronic address: mikelee@src.riken.jp.
authors.forename: M T M
authors.initials: MT
authors.lastname: Lee
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; National Center for Genome Medicine, Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan. Electronic address: iwsong16@yahoo.com.tw.
authors.forename: I-W
authors.initials: IW
authors.lastname: Song
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; National Center for Genome Medicine, Academia Sinica, Taipei, Taiwan. Electronic address: liangsuei@gmail.com.
authors.forename: L-S
authors.initials: LS
authors.lastname: Lu
authors.affiliation: Department of Orthopaedic Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: doc20231@gmail.com.
authors.forename: H-C
authors.initials: HC
authors.lastname: Shen
authors.affiliation: Department of Orthopedics, School of Medicine, College of Medicine, Taipei Medical University, Taiwan; Department of Orthopedics, Taipei Medical University Hospital, Taiwan. Electronic address: chianherlee@yahoo.com.tw.
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; National Center for Genome Medicine, Academia Sinica, Taipei, Taiwan; Translational Resource Center for Genomic Medicine, Academia Sinica, Taipei, Taiwan. Electronic address: jywu@ibms.sinica.edu.tw.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Wu
authors.affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; Department of Pediatrics, Duke University School of Medicine, Durham, NC, USA. Electronic address: chen0010@ibms.sinica.edu.tw.
authors.forename: Y-T
authors.initials: YT
authors.lastname: Chen
authors.affiliation: Duke Molecular Physiology Institute, Department of Medicine, Duke University School of Medicine, Durham, NC, USA; Department of Pathology, Duke University School of Medicine, Durham, NC, USA. Electronic address: vbk@duke.edu.
authors.forename: V B
authors.initials: VB
authors.lastname: Kraus
authors.affiliation: Department of Orthopaedic Surgery, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. Electronic address: doc20281@gmail.com.
authors.forename: C-C
authors.initials: CC
authors.lastname: Wu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005269:Femur / Q000473:pathology*; D006801:Humans; D007719:Knee Joint / Q000473:pathology*; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000235:genetics / Q000473:pathology*; D012720:Severity of Illness Index; D013977:Tibia / Q000473:pathology*; D059467:Transcriptome
keywords: Cartilage; Lateral knee compartment; Microarray; Osteoarthritis progression