Zhengmin Huang1, Haiming Xu, Linda Sandell. 1. Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, Missouri 63110, USA. huangz@msnotes.wustl.edu
Abstract
UNLABELLED: This study investigated the role of transcription factor AP-2alpha in chondrocyte differentiation in vitro. AP-2alpha mRNA declined during differentiation, and overexpression of AP-2alpha inhibited differentiation. The results demonstrated that AP-2alpha plays a negative role in chondrocyte differentiation. INTRODUCTION: Transcription factor AP-2alpha has been detected in growth plate and articular chondrocytes and has been shown to regulate cartilage matrix gene expression in vitro. However, the precise functional role of AP-2alpha in chondrocyte differentiation is not known. In this study, we assessed the expression and the function of AP-2alpha in chondrocyte differentiation of ATDC5 cells. MATERIALS AND METHODS: Chondrocyte differentiation of ATDC5 cells was induced with insulin or transforming growth factor beta (TGF-beta). Proteoglycan production was assessed by alcian blue staining, and expression levels of chondrocyte marker genes and AP-2 gene family were determined by quantitative real time reverse transcriptase-polymerase chain reaction (RT-PCR). Overexpression of AP-2alpha in ATDC5 cells was accomplished by retroviral infection. Infected cells were selected for G418 resistance and pooled for further analysis. RESULTS AND CONCLUSIONS: Quantitative real time RT-PCR analysis showed that among the four members of the AP-2 gene family, AP-2alpha mRNA was the most abundant. AP-2alpha mRNA levels progressively declined during the differentiation induced by either insulin or TGF-beta treatment. Retroviral expression of AP-2alpha in ATDC5 cells prevented the formation of cartilage nodules, suppressed the proteoglycan production, and inhibited the expression of type II collagen, aggrecan, and type X collagen. Expression profile analysis of key transcription factors involved in chondrogenesis showed that overexpression of AP-2alpha maintained the expression of Sox9 but suppressed the expression of SoxS and Sox6. Taken together, we provide, for the first time, molecular and cellular evidence suggesting that AP-2alpha is a negative regulator of chondrocyte differentiation.
UNLABELLED: This study investigated the role of transcription factor AP-2alpha in chondrocyte differentiation in vitro. AP-2alpha mRNA declined during differentiation, and overexpression of AP-2alpha inhibited differentiation. The results demonstrated that AP-2alpha plays a negative role in chondrocyte differentiation. INTRODUCTION: Transcription factor AP-2alpha has been detected in growth plate and articular chondrocytes and has been shown to regulate cartilage matrix gene expression in vitro. However, the precise functional role of AP-2alpha in chondrocyte differentiation is not known. In this study, we assessed the expression and the function of AP-2alpha in chondrocyte differentiation of ATDC5 cells. MATERIALS AND METHODS: Chondrocyte differentiation of ATDC5 cells was induced with insulin or transforming growth factor beta (TGF-beta). Proteoglycan production was assessed by alcian blue staining, and expression levels of chondrocyte marker genes and AP-2 gene family were determined by quantitative real time reverse transcriptase-polymerase chain reaction (RT-PCR). Overexpression of AP-2alpha in ATDC5 cells was accomplished by retroviral infection. Infected cells were selected for G418 resistance and pooled for further analysis. RESULTS AND CONCLUSIONS: Quantitative real time RT-PCR analysis showed that among the four members of the AP-2 gene family, AP-2alpha mRNA was the most abundant. AP-2alpha mRNA levels progressively declined during the differentiation induced by either insulin or TGF-beta treatment. Retroviral expression of AP-2alpha in ATDC5 cells prevented the formation of cartilage nodules, suppressed the proteoglycan production, and inhibited the expression of type II collagen, aggrecan, and type X collagen. Expression profile analysis of key transcription factors involved in chondrogenesis showed that overexpression of AP-2alpha maintained the expression of Sox9 but suppressed the expression of SoxS and Sox6. Taken together, we provide, for the first time, molecular and cellular evidence suggesting that AP-2alpha is a negative regulator of chondrocyte differentiation.
Authors: Sharon R Grossman; Xiaolan Zhang; Li Wang; Jesse Engreitz; Alexandre Melnikov; Peter Rogov; Ryan Tewhey; Alina Isakova; Bart Deplancke; Bradley E Bernstein; Tarjei S Mikkelsen; Eric S Lander Journal: Proc Natl Acad Sci U S A Date: 2017-01-30 Impact factor: 11.205
Authors: Maya Malaab; Ludivine Renaud; Naoko Takamura; Kip D Zimmerman; Willian A da Silveira; Paula S Ramos; Sandra Haddad; Marc Peters-Golden; Loka R Penke; Bethany Wolf; Gary Hardiman; Carl D Langefeld; Thomas A Medsger; Carol A Feghali-Bostwick Journal: Ann Rheum Dis Date: 2021-11-08 Impact factor: 19.103