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Updated: May 6, 2026
Molecular Analysis of Endothelial-mesenchymal Transition Induced by Transforming Growth Factor-β Signaling
Published on: August 3, 2018
Expression of ectonucleotide pyrophosphatase-1 in end-plate chondrocytes with transforming growth factor beta 1 siRNA
Hong-guang Xu1, Zi-rui Li, Hong Wang
1Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China (Email: xuhg@medmail.com.cn).
Background:
Ectonucleotide pyrophosphatase/phosphodiesterase (ENPP)-1 is a membrane-bound protein that catalyzes the hydrolysis of extracellular nucleoside triphosphates to monophosphate and extracellular inorganic pyrophosphate (ePPi). Mechanical stimulation regulates ENPP-1 expression. This study sought to investigate the changes in ENPP-1 expression after stimulation using cyclic mechanical tension (CMT).
Methods:
Rat end-plate chondrocytes were cultured and subjected to CMT (at 3%, 6%, and 9% elongation) for 20, 40, and 60 minutes to observe changes in the expression of ENPP-1. To investigate the pathway, end-plate chondrocytes were exposed to 10 ng/ml of transforming growth factor beta 1 (TGF-β1), TGF-β1 siRNA, or a specific extracellular signalregulated kinase (ERK)1/2 inhibitor, U0126, in addition to CMT. Changes in ENPP-1 expression were measured by reverse transcription PCR (RT-PCR) and Western blotting.
Results:
We observed the largest increase in ENPP-1 expression following 3% elongation CMT stimulation. ENPP-1 expression was also increased when end-plate chondrocytes were exposed to 10 ng/ml of TGF-β1, but decreased after TGF-β knockdown with siRNA. ERK1/2 phosphorylation was activated after 3% elongation for 40 minutes, and the stimulatory effect of TGF-β1 on ENPP-1 mRNA and protein expression was inhibited by the suppression of the ERK1/2 pathway using U0126.
Conclusion:
CMT increases the expression of ENPP-1 in end-plate chondrocytes in a manner likely dependent on TGF-β induction by the ERK1/2 signaling pathway.
