Reduction of WDR81 impairs autophagic clearance of aggregated proteins and cell viability in neurodegenerative phenotypes

Betaine enhances SCAPs chondrogenic differentiation and promotes cartilage repair in TMJOA through WDR81

BACKGROUND

The cartilage tissue regeneration mediated with mesenchymal stem cells (MSCs) is considered as a viable strategy for temporomandibular joint osteoarthritis (TMJOA). Betaine has been confirmed to modulate the multidirectional differentiation of MSCs, while its effect on chondrogenic differentiation of Stem Cells from the Apical Papilla (SCAPs) is unknown. Here, we explored the effects and underlying mechanisms of betaine on chondrogenic differentiation of SCAPs.

METHODS

Betaine was added for SCAPs chondrogenic induction. The chondrogenic differentiation potential was assessed using Alcian Blue staining, Sirius Red staining and the main chondrogenic markers. In vivo cartilage regeneration effects were evaluated by the rat TMJOA model. RNA-sequencing and biological analyses were performed to select target genes and biological processes involved. The mechanism betaine acts on chondrogenic differentiation of SCAPs was further explored.

RESULTS

Betain-treated SCAPs demonstrated stronger cartilage regeneration in vitro and promoted cartilage repair of TMJOA in vivo. Betaine enhanced the expression of WDR81 in SCAPs during chondrogenesis. WDR81 overexpression promoted chondrogenic differentiation of SCAPs, while WDR81 depletion inhibited chondrogenic differentiation. In addition, both betaine treatment and WDR81 overexpression reduced intracellular reactive oxygen species levels and increased mitochondrial membrane potential in SCAPs.

CONCLUSION

Betaine promotes SCAPs chondrogenic differentiation and provided an effective candidate for TMJOA treatment. WDR81 may serve as the potential drug target through mitophagy.