Tissue transglutaminase is involved in mechanical load-induced osteogenic differentiation of human ligamentum flavum cells.
Mechanical load-induced osteogenic differentiation might be the key cellular event in the calcification and ossification of ligamentum flavum. The aim of this study was to investigate the influence of tissue transglutaminase (TGM2) on mechanical load-induced osteogenesis of ligamentum flavum cells. Human ligamentum flavum cells were obtained from 12 patients undergoing lumbar spine surgery. Osteogenic phenotypes of ligamentum flavum cells, such as alkaline phosphatase (ALP), Alizarin red-S stain, and gene expression of osteogenic makers were evaluated following the administration of mechanical load and BMP-2 treatment. The expression of TGM2 was evaluated by real-time PCR, Western blotting, and enzyme-linked immunosorbent assay (ELISA) analysis. Our results showed that mechanical load in combination with BMP-2 enhanced calcium deposition and ALP activity. Mechanical load significantly increased ALP and OC gene expression on day 3, whereas BMP-2 significantly increased ALP, OPN, and Runx2 on day 7. Mechanical load significantly induced TGM2 gene expression and enzyme activity in human ligamentum flavum cells. Exogenous TGM2 increased ALP and OC gene expression; while, inhibited TG activity significantly attenuated mechanical load-induced and TGM2-induced ALP activity. In summary, mechanical load-induced TGM2 expression and enzyme activity is involved in the progression of the calcification of ligamentum flavum.
a School and Graduate Institute of Physical Therapy, College of Medicine, National Taiwan University , Taipei , Taiwan.
Yuan-Hung
YH
Chao
b Institute of Biomedical Engineering, National Yang-Ming University , Taipei , Taiwan.
Shih-Yung
SY
Huang
c Department of Orthopedic Surgery , Taipei City Hospital Zhongxing Branch , Taipei , Taiwan.
Ruei-Cheng
RC
Yang
d Department of Orthopedic Surgery , College of Medicine, National Taiwan University , Taipei , Taiwan.|e Department of Orthopedic Surgery , National Taiwan University Hospital , Taipei , Taiwan.|f Biomimetic Systems Research Center, National Chiao Tung University , Hsin-Chu , Taiwan.
Jui-Sheng
JS
Sun
D000469:Alkaline Phosphatase / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000494:pharmacology; D002113:Calcification, Physiologic / Q000187:drug effects / Q000235:genetics; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D017843:Ligamentum Flavum / Q000166:cytology*; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D060888:Real-Time Polymerase Chain Reaction; D013314:Stress, Mechanical; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D016474:Weight-Bearing
D055396:Bone Morphogenetic Protein 2; C000717608:TGM2 protein, human; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D000469:Alkaline Phosphatase; D019204:GTP-Binding Proteins
Ligamentum flavum cells; mechanical load; osteogenic differentiation; spinal stenosis; tissue transglutaminase