NSUN2 facilitates tenogenic differentiation of rat tendon-derived stem cells via m5C methylation of KLF2.

INTRODUCTION

Tendon-derived stem cells (TDSCs) play a critical role in tendon repair. N5-methylcytosine (m5C) is a key regulator of cellular processes such as differentiation. This study aimed to investigate the impact of m5C on TDSC differentiation and the underlying mechanism.

METHODS

TDSCs were isolated from rats and identified, and a tendon injury rat model was generated. Tenogenic differentiation was evaluated using Sirius red staining and quantitative real-time polymerase chain reaction, while that was assessed using immunohistochemistry and hematoxylin‒eosin staining. m5C methylation was analyzed using methylated RNA immunoprecipitation, dual-luciferase reporter assay, and RNA stability assay.

RESULTS

The results showed that m5C levels and NSUN2 expression were increased in TDSCs after tenogenic differentiation. Knockdown of NSUN2 inhibited m5C methylation of KLF2 and decreased its stability, which was recognized by YBX1. Moreover, interfering with KLF2 suppressed tenogenic differentiation of TDSCs, which could be abrogated by KLF2 overexpression. Additionally, TDSCs after NSUN2 overexpression contributed to ameliorating tendon injury . In conclusion, NSUN2 promotes tenogenic differentiation of TDSCs via m5C methylation of KLF2 and accelerates tendon repair.

CONCLUSIONS

The findings suggest that overexpression of NSUN2 can stimulate the differentiation ability of TDSCs, which can be used in the treatment of tendinopathy.