Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Mar 26;26(13):3643-3656.e7.
doi: 10.1016/j.celrep.2019.02.088.

Maintenance of Nucleolar Homeostasis by CBX4 Alleviates Senescence and Osteoarthritis

Affiliations
Free article

Maintenance of Nucleolar Homeostasis by CBX4 Alleviates Senescence and Osteoarthritis

Xiaoqing Ren et al. Cell Rep. .
Free article

Abstract

CBX4, a component of polycomb repressive complex 1 (PRC1), plays important roles in the maintenance of cell identity and organ development through gene silencing. However, whether CBX4 regulates human stem cell homeostasis remains unclear. Here, we demonstrate that CBX4 counteracts human mesenchymal stem cell (hMSC) aging via the maintenance of nucleolar homeostasis. CBX4 protein is downregulated in aged hMSCs, whereas CBX4 knockout in hMSCs results in destabilized nucleolar heterochromatin, enhanced ribosome biogenesis, increased protein translation, and accelerated cellular senescence. CBX4 maintains nucleolar homeostasis by recruiting nucleolar protein fibrillarin (FBL) and heterochromatin protein KRAB-associated protein 1 (KAP1) at nucleolar rDNA, limiting the excessive expression of rRNAs. Overexpression of CBX4 alleviates physiological hMSC aging and attenuates the development of osteoarthritis in mice. Altogether, our findings reveal a critical role of CBX4 in counteracting cellular senescence by maintaining nucleolar homeostasis, providing a potential therapeutic target for aging-associated disorders.

Keywords: CBX4; CRISPR/Cas9; aging; epigenetics; gene editing; heterochromatin; nucleolus; osteoarthritis; rDNA; stem cell.

PubMed Disclaimer

Publication types