Histone deacetylase 4 deletion results in abnormal chondrocyte hypertrophy and premature ossification from collagen type 2α1‑expressing cells

Mol Med Rep. 2020 Nov;22(5):4031-4040. doi: 10.3892/mmr.2020.11465. Epub 2020 Aug 27.

Abstract

Histone deacetylase 4 (HDAC4) plays a vital role in chondrocyte hypertrophy and bone formation. To investigate the function of HDAC4 in postnatal skeletal development, the present study developed lineage‑specific HDAC4‑knockout mice [collagen type 2α1 (Col2α1)‑Cre, HDAC4d/d mice] by crossing transgenic mice expressing Cre recombinase. Thus, a specific ablation of HDAC4 was performed in Col2α1‑expressing mice cells. The knee joints of HDAC4fl/fl and Col2α1‑Cre, HDAC4d/d mice were analyzed at postnatal day (P)2‑P21 using an in vivo bromodeoxyuridine (BrdU) assay, and Safranin O, Von Kossa and whole‑body staining were used to evaluate the developmental growth plate, hypertrophic differentiation, mineralization and skeletal mineralization patterns. The trabecular bone was analyzed using microcomputed tomography. The expressions of BrdU, proliferating cell nuclear antigen (PCNA), matrix metalloproteinase (MMP)‑13, runt‑related transcription factor (Runx)‑2, osteoprotegerin (OPG), CD34, type X collagen (ColX), osteocalcin and Wnt5a were determined using immunohistochemistry, in situ hybridization (ISH) and reverse transcription‑quantitative (RT‑q)PCR. The results demonstrated that HDAC4‑null mice (HDAC4d/d mice) were severely runted; these mice had a shortened hypertrophic zone (histopathological evaluation), accelerated vascular invasion and articular mineralization (Von Kossa staining), elevated expressions of MMP‑13, Runx2, OPG and CD34 (RT‑qPCR and immunohistochemistry), downregulated expression of the proliferative marker BrdU and PCNA (immunohistochemistry), increased expression of ColX and decreased expression of Wnt5a (ISH). In conclusion, chondrocyte‑derived HDAC4 was responsible for regulating chondrocyte proliferation and differentiation as well as endochondral bone formation.

MeSH terms

  • Animals
  • Cancellous Bone / pathology
  • Cell Differentiation / genetics
  • Cell Enlargement*
  • Cell Proliferation / genetics
  • Cells, Cultured
  • Chondrocytes / metabolism*
  • Chondrogenesis / genetics
  • Collagen Type II / metabolism*
  • Collagen Type X / genetics
  • Collagen Type X / metabolism
  • Core Binding Factor Alpha 1 Subunit / genetics
  • Core Binding Factor Alpha 1 Subunit / metabolism
  • Female
  • Gene Deletion*
  • Histone Deacetylases / genetics*
  • Histone Deacetylases / metabolism*
  • Male
  • Matrix Metalloproteinase 13 / genetics
  • Matrix Metalloproteinase 13 / metabolism
  • Mice
  • Mice, Knockout
  • Osteogenesis / genetics*
  • X-Ray Microtomography

Substances

  • Col2a1 protein, mouse
  • Collagen Type II
  • Collagen Type X
  • Core Binding Factor Alpha 1 Subunit
  • Runx2 protein, mouse
  • Matrix Metalloproteinase 13
  • Mmp13 protein, mouse
  • Hdac5 protein, mouse
  • Histone Deacetylases