Calcified Tissue International

, Volume 80, Issue 3, pp 201–210

Insulin-Like Effects of Visfatin on Human Osteoblasts

  • H. Xie
  • S.-Y. Tang
  • X.-H. Luo
  • J. Huang
  • R.-R. Cui
  • L.-Q. Yuan
  • H.-D. Zhou
  • X.-P. Wu
  • E.-Y. Liao
Article

DOI: 10.1007/s00223-006-0155-7

Cite this article as:
Xie, H., Tang, SY., Luo, XH. et al. Calcif Tissue Int (2007) 80: 201. doi:10.1007/s00223-006-0155-7

Abstract

Visfatin (also known as pre-B cell colony-enhancing factor or PBEF) is a novel adipocytokine that is highly expressed in visceral fat and upregulated in obesity and type 2 diabetes mellitus. Visfatin binds to and activates the insulin receptor (IR), thereby exerting insulin-mimetic effects in various cell lines. IR has been detected in osteoblasts, which is consistent with the role of insulin as an important osteotropic hormone. This study investigated the actions of visfatin on human primary osteoblasts. The expression and tyrosine phosphorylation of IR, IR substrate-1 (IRS-1), and IRS-2 were determined by immunoprecipitation and immunoblotting. Cell proliferation was determined by measuring [3H]thymidine incorporation and cell number. Glucose uptake was determined by measuring 2-[3H]deoxyglucose incorporation. Real-time quantitative reverse-transcription polymerase chain reaction (PCR) was used for determining alkaline phosphatase (ALP), osteocalcin, and type I collagen mRNA expression. Enzyme-linked immunosorbent assay and radioimmunoassay were used for measuring ALP activity, osteocalcin secretion, and type I collagen production. We found that visfatin induced tyrosine phosphorylation of IR, IRS-1, and IRS-2. Moreover, the effects of visfatin – glucose uptake, proliferation, and type I collagen enhancement of cultured human osteoblast-like cells – bore a close resemblance to those of insulin and were inhibited by hydroxy-2-naphthalenylmethylphosphonic acid tris-acetoxymethyl ester, a specific inhibitor of IR tyrosine kinase activity. We also unexpectedly found that visfatin downregulated osteocalcin secretion from human osteoblast-like cells. These data indicate that the regulation of glucose uptake, proliferation, and type I collagen production by visfatin in human osteoblasts involves IR phosphorylation, the same signal-transduction pathway used by insulin.

Keywords

Visfatin Insulin Osteoblast Proliferation Type I collagen 

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • H. Xie
    • 1
  • S.-Y. Tang
    • 1
    • 2
  • X.-H. Luo
    • 1
  • J. Huang
    • 1
  • R.-R. Cui
    • 1
  • L.-Q. Yuan
    • 1
  • H.-D. Zhou
    • 1
  • X.-P. Wu
    • 1
  • E.-Y. Liao
    • 1
  1. 1.Institute of Endocrinology and MetabolismSecond Xiangya Hospital of Central South UniversityHunanPeople’s Republic of China
  2. 2.School of NursingCentral South UniversityHunanPeople’s Republic of China

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