The promyelotic leukemia zinc finger promotes osteoblastic differentiation of human mesenchymal stem cells as an upstream regulator of CBFA1.
Ossification of the posterior longitudinal ligament of the spine (OPLL) is the leading cause of myelopathy in Japan and is diagnosed by ectopic bone formation in the paravertebral ligament. OPLL is a systemic high bone mass disease with a strong genetic background. To detect genes relevant to the pathogenesis of OPLL, we performed a cDNA microarray analysis of systematic gene expression profiles during the osteoblastic differentiation of ligament cells from OPLL patients (OPLL cells), patients with a disorder called ossification of yellow ligament (OYL), and non-OPLL controls together with human mesenchymal stem cells (hMSCs) after stimulating them with osteogenic differentiation medium (OS). Twenty-four genes were up-regulated during osteoblastic differentiation in OPLL cells. Zinc finger protein 145 (promyelotic leukemia zinc finger or PLZF) was one of the highly expressed genes during osteoblastic differentiation in all the cells examined. We investigated the roles of PLZF in the regulation of osteoblastic differentiation of hMSCs and C2C12 cells. Small interfering RNA-mediated gene silencing of PLZF resulted in a reduction in the expression of osteoblast-specific genes such as the alkaline phosphatase, collagen 1A1 (Col1a1), Runx2/core-binding factor 1 (Cbfa1), and osteocalcin genes, even in the presence of OS in hMSCs. The expression of PLZF was unaffected by the addition of bone morphogenetic protein 2 (BMP-2), and the expression of BMP-2 was not affected by PLZF in hMSCs. In C2C12 cells, overexpression of PLZF increased the expression of Cbfa1 and Col1a1; on the other hand, the overexpression of CBFA1 did not affect the expression of Plzf. These findings indicate that PLZF plays important roles in early osteoblastic differentiation as an upstream regulator of CBFA1 and thereby might participate in promoting the ossification of spinal ligament cells in OPLL patients.
Ikeda
Ryuji
R
Division of Genetic Diagnosis, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
Yoshida
Kenichi
K
Tsukahara
So
S
Sakamoto
Yoshiko
Y
Tanaka
Hiroshi
H
Furukawa
Ken-ichi
K
Inoue
Ituro
I
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D005822:Genetic Vectors; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D008022:Ligaments / Q000378:metabolism; D051379:Mice; D009363:Neoplasm Proteins / Q000737:chemistry*; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering / Q000378:metabolism; D013122:Spinal Diseases / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism*; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation; D016335:Zinc Fingers
D050659:Core Binding Factor Alpha 1 Subunit; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; D009363:Neoplasm Proteins; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D034741:RNA, Small Interfering; D014157:Transcription Factors; C513267:Zbtb16 protein, mouse; C092037:ZBTB16 protein, human; D000469:Alkaline Phosphatase