Inhibition of CD44 intracellular domain production suppresses bovine articular chondrocyte de-differentiation induced by excessive mechanical stress loading

Yasumori Sobue,Yoshifumi Ohashi,Mochihito Suzuki,Kenya Terabe,Warren Knudson,Cheryl Knudson,Tomonori Kobayakawa,Toshihisa Kojima,Nobunori Takahashi,Tsuyoshi Nishiume,Naoki Ishiguro

doi:10.1038/s41598-019-50166-4

Yasumori Sobue, Yoshifumi Ohashi + Show 9 more

Open Access

https://doi.org/10.1038/s41598-019-50166-4

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Journal: Scientific Reports	Publication Date: Oct 17, 2019
Citations: 8	License type: open-access

Affiliation: Nagoya University, East Carolina University

Abstract

CD44 fragmentation is enhanced in chondrocytes of osteoarthritis (OA) patients. We hypothesized that mechanical stress-induced enhancement of CD44-intracellular domain (CD44-ICD) production plays an important role in the de-differentiation of chondrocytes and OA. This study aimed to assess the relationship between CD44-ICD and chondrocyte gene expression. Monolayer cultured primary bovine articular chondrocytes (BACs) were subjected to cyclic tensile strain (CTS) loading. ADAM10 inhibitor (GI254023X) and γ-secretase inhibitor (DAPT) were used to inhibit CD44 cleavage. In overexpression experiments, BACs were electroporated with a plasmid encoding CD44-ICD. CTS loading increased the expression of ADAM10 and subsequent CD44 cleavage, while decreasing the expression of SOX9, aggrecan, and type 2 collagen (COL2). Overexpression of CD44-ICD also resulted in decreased expression of these chondrocyte genes. Both GI254023X and DAPT reduced the production of CD44-ICD upon CTS loading, and significantly rescued the reduction of SOX9 expression by CTS loading. Chemical inhibition of CD44-ICD production also rescued aggrecan and COL2 expression following CTS loading. Our findings suggest that CD44-ICD is closely associated with the de-differentiation of chondrocytes. Excessive mechanical stress loading promoted the de-differentiation of BACs by enhancing CD44 cleavage and CD44-ICD production. Suppression of CD44 cleavage has potential as a novel treatment strategy for OA.

Highlights

Osteoarthritis (OA) is characterized by both the degradation of articular cartilage and the destruction of joints as a result of loss of homeostasis in articular cartilage[1]
bovine articular chondrocytes (BACs) became spindle-shaped at 48 hours, with the long axis orthogonally oriented to the axis of stress loading (Fig. 1B)
We found that excessive mechanical stress loading induces the de-differentiation of articular chondrocytes via CD44 cleavage and subsequent CD44-ICD production

Summary

Introduction

Osteoarthritis (OA) is characterized by both the degradation of articular cartilage and the destruction of joints as a result of loss of homeostasis in articular cartilage[1]. Can induce chondrocyte de-differentiation, articular cartilage degradation, and OA onset[7,8,9], and alter the expression of various catabolic and anabolic genes that regulate cartilage remodeling and turnover, potentially leading to proteolytic cleavage of the extracellular matrix[10]. We previously found that mechanical stress loading increased ADAM10 expression and CD44 cleavage via TRPV4 activation in a human chondrocyte cell line (HCS)[19]. The release of these CD44 fragments can negatively impact chondrocyte function. This study aimed to assess the effect of CD44-ICD on the de-differentiation of primary BACs induced by excessive mechanical stress loading

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Conclusion