CBX4 and osteoarthritis: The same protocol for exploring target genes was used to discover and validate the CBX4 gene by Liu et al. They utilized a CRISPR-Cas system to construct CBX4 knockout human mesenchymal stem cell (hMSC) models and found that deficiency of CBX4 leads to cellular senescence, whereas its overexpression alleviates cellular senescence and subsequent osteoarthritis through maintaining nucleolar homeostasis [138].