Comparison of secretome from osteoblasts derived from sclerotic versus non-sclerotic subchondral bone in OA: A pilot study

PLoS One. 2018 Mar 16;13(3):e0194591. doi: 10.1371/journal.pone.0194591. eCollection 2018.

Abstract

Objective: Osteoarthritis (OA) is characterized by cartilage degradation but also by other joint tissues modifications like subchondral bone sclerosis. In this study, we used a proteomic approach to compare secretome of osteoblast isolated from sclerotic (SC) or non sclerotic (NSC) area of OA subchondral bone.

Design: Secretome was analyzed using differential quantitative and relative label free analysis on nanoUPLC G2 HDMS system. mRNA of the more differentially secreted proteins were quantified by RT-PCR in cell culture from 5 other patients. Finally, osteomodulin and fibulin-3 sequences were quantified by western blot and immunoassays in serum and culture supernatants.

Results: 175 proteins were identified in NSC osteoblast secretome. Data are available via ProteomeXchange with identifier PXD008494. Compared to NSC osteoblast secretome, 12 proteins were significantly less secreted (Osteomodulin, IGFBP5, VCAM-1, IGF2, 78 kDa glucose-regulated protein, versican, calumenin, IGFBP2, thrombospondin-4, periostin, reticulocalbin 1 and osteonectin), and 13 proteins were significantly more secreted by SC osteoblasts (CHI3L1, fibulin-3, SERPINE2, IGFBP6, SH3BGRL3, SERPINE1, reticulocalbin3, alpha-2-HS-glycoprotein, TIMP-2, IGFBP3, TIMP-1, SERPINF1, CSF-1). Similar changes in osteomodulin, IGF2, SERPINE1, fibulin-3 and CHI3L1 mRNA levels were observed. ELISAs assays confirm the decrease by half of osteomodulin protein in SC osteoblasts supernatant compared to NSC and in OA patients serum compared to healthy subjects. Fibulin-3 epitopes Fib3-1, Fib3-2 and Fib3-3 were also increased in SC osteoblasts supernatant compared to NSC.

Conclusions: We highlighted some proteins differentially secreted by the osteoblasts coming from OA subchondral bone sclerosis. These changes contribute to explain some features observed in OA subchondral bone, like the increase of bone remodeling or abnormalities in bone matrix mineralization. Among identified proteins, osteomodulin was found decreased and fibulin-3 increased in serum of OA patients. These findings suggest that osteomodulin and fibulin-3 fragments could be biomarkers to monitor early changes in subchondral bone metabolism in OA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / analysis
  • Bone Remodeling / physiology
  • Bone and Bones / cytology
  • Bone and Bones / metabolism*
  • Bone and Bones / pathology
  • Calcification, Physiologic
  • Cells, Cultured
  • Enzyme-Linked Immunosorbent Assay
  • Extracellular Matrix Proteins / metabolism*
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis, Knee / diagnosis
  • Osteoarthritis, Knee / pathology*
  • Osteoblasts / metabolism*
  • Osteosclerosis / pathology*
  • Pilot Projects
  • Proteoglycans / metabolism*
  • Proteomics
  • RNA, Messenger / metabolism

Substances

  • Biomarkers
  • EFEMP1 protein, human
  • Extracellular Matrix Proteins
  • Proteoglycans
  • RNA, Messenger
  • osteoadherin

Grants and funding

The D-Board project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement No. 305815 to Christelle Sanchez and Yves Henrotin. The funding sources had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.