Local origins impart conserved bone type-related differences in human osteoblast behaviour

Eur Cell Mater. 2015 Mar 4:29:155-75; discussion 175-6. doi: 10.22203/ecm.v029a12.

Abstract

Osteogenic behaviour of osteoblasts from trabecular, cortical and subchondral bone were examined to determine any bone type-selective differences in samples from both osteoarthritic (OA) and osteoporotic (OP) patients. Cell growth, differentiation; alkaline phosphatase (TNAP) mRNA and activity, Runt-related transcription factor-2 (RUNX2), SP7-transcription factor (SP7), bone sialoprotein-II (BSP-II), osteocalcin/bone gamma-carboxyglutamate (BGLAP), osteoprotegerin (OPG, TNFRSF11B), receptor activator of nuclear factor-κβ ligand (RANKL, TNFSF11) mRNA levels and proangiogenic vascular endothelial growth factor-A (VEGF-A) mRNA and protein release were assessed in osteoblasts from paired humeral head samples from age-matched, human OA/OP (n = 5/4) patients. Initial outgrowth and increase in cell number were significantly faster (p < 0.01) in subchondral and cortical than trabecular osteoblasts, in OA and OP, and this bone type-related differences were conserved despite consistently faster growth in OA. RUNX2/SP7 levels and TNAP mRNA and protein activity were, however, greater in trabecular than subchondral and cortical osteoblasts in OA and OP. BSP-II levels were significantly greater in trabecular and lowest in cortical osteoblasts in both OA and OP. In contrast, BGLAP levels showed divergent bone type-selective behaviour; highest in osteoblasts from subchondral origins in OA and trabecular origins in OP. We found virtually identical bone type-related differences, however, in TNFRSF11B:TNFSF11 in OA and OP, consistent with greater potential for paracrine effects on osteoclasts in trabecular osteoblasts. Subchondral osteoblasts (OA) exhibited highest VEGF-A mRNA levels and release. Our data indicate that human osteoblasts in trabecular, subchondral and cortical bone have inherent, programmed diversity, with specific bone type-related differences in growth, differentiation and pro-angiogenic potential in vitro.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Alkaline Phosphatase / genetics
  • Alkaline Phosphatase / metabolism
  • Bone and Bones / metabolism*
  • Bone and Bones / pathology
  • Cell Differentiation / genetics*
  • Cell Proliferation / genetics*
  • Cells, Cultured
  • Core Binding Factor Alpha 1 Subunit / genetics
  • Core Binding Factor Alpha 1 Subunit / metabolism
  • Female
  • Gene Expression Profiling
  • Humans
  • Integrin-Binding Sialoprotein / genetics
  • Integrin-Binding Sialoprotein / metabolism
  • Organ Specificity / genetics
  • Osteoarthritis / genetics*
  • Osteoarthritis / metabolism
  • Osteoarthritis / pathology
  • Osteoblasts / metabolism*
  • Osteocalcin / genetics
  • Osteocalcin / metabolism
  • Osteoporosis / genetics*
  • Osteoporosis / metabolism
  • Osteoporosis / pathology
  • Osteoprotegerin / genetics
  • Osteoprotegerin / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sp7 Transcription Factor
  • Tissue Culture Techniques
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Core Binding Factor Alpha 1 Subunit
  • Integrin-Binding Sialoprotein
  • Osteoprotegerin
  • Sp7 Transcription Factor
  • SP7 protein, human
  • Transcription Factors
  • Vascular Endothelial Growth Factor A
  • Osteocalcin
  • Alkaline Phosphatase