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p57Kip2 is an essential regulator of vitamin D receptor-dependent mechanisms

Katsuhiko Takahashi1,2, Hitoshi Amano1,3,4, Tomohiko Urano5,6

  • 1Department of Biochemistry, Hoshi University, Ebara, Shinagawa-ku, Tokyo.

Plos One
|February 15, 2023
PubMed

Insights

The study reveals that p57Kip2 is crucial for vitamin D

Area of Science:

  • Molecular Biology
  • Developmental Biology
  • Cell Biology

Background:

  • p57Kip2 is a cyclin-dependent kinase inhibitor vital for bone development.
  • p57Kip2 deficiency in mice leads to neonatal lethality due to bone and palate abnormalities.
  • 1α,25-dihydroxyvitamin D3 (1,25-(OH)2VD3) influences cell proliferation and differentiation.

Purpose of the Study:

  • To investigate the role of p57Kip2 in 1,25-(OH)2VD3-regulated osteoblast differentiation.
  • To understand the association between p57Kip2 and the vitamin D receptor (VDR).

Main Methods:

  • Assessed p57Kip2 expression and localization with VDR in osteoblasts.
  • Compared proliferation and mineralization in p57Kip2-deficient (p57-/-) and wild-type (p57+/+) osteoblasts.
  • Analyzed mRNA expression of p57Kip2 and osteopontin (opn) following 1,25-(OH)2VD3 treatment.
  • Evaluated osteoclastogenesis using co-cultures with treated osteoblasts.

Main Results:

  • 1,25-(OH)2VD3 increased p57Kip2 expression and nuclear co-localization with VDR.
  • p57-/- osteoblasts showed increased proliferation and reduced mineralization compared to p57+/+ cells.
  • 1,25-(OH)2VD3 upregulated p57Kip2 and opn mRNA in p57+/+ cells, but opn was decreased in p57-/- cells.
  • Osteoclastogenesis was less efficient in p57-/- cells treated with 1,25-(OH)2VD3.

Conclusions:

  • p57Kip2 acts as a mediator in 1,25-(OH)2VD3 signaling pathways.
  • Sufficient VDR activation for osteoblast maturation depends on p57Kip2.
  • p57Kip2 is essential for normal bone development regulated by vitamin D.

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