Age-related matrix stiffening epigenetically regulates α-Klotho expression and compromises chondrocyte integrity

Hirotaka Iijima, Gabrielle Gilmer, Kai Wang, Allison C. Bean, Yuchen He, Hang Lin, Wan Yee Tang, Daniel Lamont, Chia Tai, Akira Ito, Jeffrey J. Jones, Christopher Evans, Fabrisia Ambrosio

Research output: Contribution to journalArticlepeer-review


Extracellular matrix stiffening is a quintessential feature of cartilage aging, a leading cause of knee osteoarthritis. Yet, the downstream molecular and cellular consequences of age-related biophysical alterations are poorly understood. Here, we show that epigenetic regulation of α-Klotho represents a novel mechanosensitive mechanism by which the aged extracellular matrix influences chondrocyte physiology. Using mass spectrometry proteomics followed by a series of genetic and pharmacological manipulations, we discovered that increased matrix stiffness drove Klotho promoter methylation, downregulated Klotho gene expression, and accelerated chondrocyte senescence in vitro. In contrast, exposing aged chondrocytes to a soft matrix restored a more youthful phenotype in vitro and enhanced cartilage integrity in vivo. Our findings demonstrate that age-related alterations in extracellular matrix biophysical properties initiate pathogenic mechanotransductive signaling that promotes Klotho promoter methylation and compromises cellular health. These findings are likely to have broad implications even beyond cartilage for the field of aging research.

Original languageEnglish (US)
Article number18
JournalNature communications
Issue number1
StatePublished - Dec 2023
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Biochemistry, Genetics and Molecular Biology
  • General Physics and Astronomy


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