title: Bone morphogenetic protein 2/SMAD signalling in human ligamentocytes of degenerated and aged anterior cruciate ligaments.
abstract: Anterior cruciate ligament (ACL) degeneration leads to knee instability and favors osteoarthritis (OA) progression. During ageing the growth factor sensitivity of ligaments changes but nothing is known about BMP2-signalling and -sensitivity in degenerated ACLs. This study addressed the question whether a dysregulated BMP2 signalling might contribute to age- and OA-dependent ACL degeneration.
  
  
  
  ACL samples from patients with/without OA of different ages (<60 and ≥60 years, males, females) were graded histopathologically (n = 45). After stimulation of cultured ACL fibroblasts with 5 nM BMP2 for different time points, phosphorylation of SMAD1/5/8 and gene expression of crucial BMP2 signalling proteins, ligamentogenic and chondrogenic transcription factors, scleraxis (SCX) and SOX9, were analyzed.
  
  
  
  ACL samples displayed different grades of degeneration, often associated with synovitis and calcium deposits. Degeneration correlated significantly with synovitis. ACL fibroblasts expressed BMP type I receptors ALK3 and ALK6 and the BMP type II receptor BMPRII. Donors could be divided into "responders" and "non responders" since their BMP2 mediated SMAD1/5/8 phosphorylation level differed. Basal ID1 expression was lower in cells derived from OA compared with non-OA patients and BMP2 led to an ID1 induction in both. Irrespective of BMP2 stimulation, the donor age significantly influenced the expression profile of BMP6 and SCX but not BMP signalling. The BMP2-mediated SMAD6 expression differed between OA and healthy ACL fibroblasts.
  
  
  
  Our data indicate that the expression level of BMP2/SMAD target genes such as ID1 and SMAD6 was reduced in ACL fibroblasts derived from OA compared with non OA patients.
authors.affiliation: Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Ruschke
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Meier
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Ullah
authors.affiliation: Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany; Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: A-C
authors.initials: AC
authors.lastname: Krebs
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Silberreis
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Kohl
authors.affiliation: Freie Universität Berlin, Institute of Chemistry and Biochemistry, Berlin, Germany; Berlin-Brandenburg Center for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Knaus
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Jagielski
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Arens
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Orthopaedic, Trauma and Reconstructive Surgery, Campus Benjamin Franklin, Berlin, Germany; Institute of Anatomy, Paracelsus Medical University, Salzburg and Nuremberg, Nuremberg, Germany. Electronic address: gundula.schulze@pmu.ac.at.
authors.forename: G
authors.initials: G
authors.lastname: Schulze-Tanzil
mesh_terms: D016118:Anterior Cruciate Ligament; D055396:Bone Morphogenetic Protein 2; D020219:Chondrogenesis; D005260:Female; D005347:Fibroblasts; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2
keywords: Ageing; Anterior cruciate ligament degeneration; BMP2 signalling; Ligament fibroblasts; Osteoarthritis; Phospho SMAD