Yes-associated protein nuclear translocation promotes anabolic activity in human articular chondrocytes

Y Cui; M Z Miao; M Wang; Q P Su; K Qiu; L Arbeeva; S Chubinskaya; B O Diekman; R F Loeser

doi:10.1016/j.joca.2023.04.006

Yes-associated protein nuclear translocation promotes anabolic activity in human articular chondrocytes

Osteoarthritis Cartilage. 2023 Aug;31(8):1078-1090. doi: 10.1016/j.joca.2023.04.006. Epub 2023 Apr 24.

Authors

Y Cui¹, M Z Miao², M Wang³, Q P Su⁴, K Qiu⁵, L Arbeeva⁶, S Chubinskaya⁷, B O Diekman⁸, R F Loeser⁹

Affiliations

¹ Xiangya International Medical Center, Xiangya Hospital, Central South University, Changsha, Hunan Province, 410008, China; Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA. Electronic address: cuiyang@csu.edu.cn.
² Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Division of Oral & Craniofacial Health Sciences, University of North Carolina Adams School of Dentistry, Chapel Hill, NC, 27599, USA. Electronic address: zhemiao@unc.edu.
³ Division of Pharmacoengineering and Molecular Pharmaceutics, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, 27599, USA. Electronic address: menglin@email.unc.edu.
⁴ School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW, 2007, Australia. Electronic address: qian.su@uts.edu.au.
⁵ Division of Pharmacoengineering and Molecular Pharmaceutics, University of North Carolina Eshelman School of Pharmacy, Chapel Hill, NC, 27599, USA. Electronic address: kunyuqiu2017@outlook.com.
⁶ Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA. Electronic address: liubov_arbeeva@med.unc.edu.
⁷ Department of Pediatrics, Rush University Medical Center, Chicago, IL, 60612, USA. Electronic address: susanna_chubinskaya@rush.edu.
⁸ Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA; Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Raleigh, NC, 27599, USA. Electronic address: bdiekman@email.unc.edu.
⁹ Thurston Arthritis Research Center, University of North Carolina School of Medicine, Chapel Hill, NC, 27599, USA. Electronic address: richard_loeser@med.unc.edu.

PMID: 37100374
PMCID: PMC10524185 (available on 2024-08-01)
DOI: 10.1016/j.joca.2023.04.006

Abstract

Objective: Yes-associated protein (YAP) has been widely studied as a mechanotransducer in many cell types, but its function in cartilage is controversial. The aim of this study was to identify the effect of YAP phosphorylation and nuclear translocation on the chondrocyte response to stimuli relevant to osteoarthritis (OA).

Design: Cultured normal human articular chondrocytes from 81 donors were treated with increased osmolarity media as an in vitro model of mechanical stimulation, fibronectin fragments (FN-f) or IL-1β as catabolic stimuli, and IGF-1 as an anabolic stimulus. YAP function was assessed with gene knockdown and inhibition by verteporfin. Nuclear translocation of YAP and its transcriptional co-activator TAZ and site-specific YAP phosphorylation were determined by immunoblotting. Immunohistochemistry and immunofluorescence to detect YAP were performed on normal and OA human cartilage with different degrees of damage.

Results: Chondrocyte YAP/TAZ nuclear translocation increased under physiological osmolarity (400 mOsm) and IGF-1 stimulation, which was associated with YAP phosphorylation at Ser128. In contrast, catabolic stimulation decreased the levels of nuclear YAP/TAZ through YAP phosphorylation at Ser127. Following YAP inhibition, anabolic gene expression and transcriptional activity decreased. Additionally, YAP knockdown reduced proteoglycan staining and levels of type II collagen. Total YAP immunostaining was greater in OA cartilage, but YAP was sequestered in the cytosol in cartilage areas with more severe damage.

Conclusions: YAP chondrocyte nuclear translocation is regulated by differential phosphorylation in response to anabolic and catabolic stimuli. Decreased nuclear YAP in OA chondrocytes may contribute to reduced anabolic activity and promotion of further cartilage loss.

Keywords: Chondrocytes; Differential phosphorylation; Mechanotransduction; Nuclear translocation; Yes-associated protein.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Cartilage, Articular* / metabolism
Cells, Cultured
Chondrocytes / metabolism
Humans
Insulin-Like Growth Factor I / pharmacology
Osteoarthritis* / metabolism
Transcription Factors / genetics
YAP-Signaling Proteins*

Substances

Insulin-Like Growth Factor I
Transcription Factors
YAP-Signaling Proteins
YY1AP1 protein, human

Abstract

Publication types

MeSH terms

Substances

Grants and funding