Proteomic Dynamics Reveal Cell-Cycle and Rho GTPase Remodeling Associated with Transient Senescence Traits in Human Chondrocytes During Sustained IL-1β Signaling

Chronic inflammatory signaling contributes to cartilage degeneration across multiple joint diseases, yet the molecular consequences of sustained cytokine exposure remain incompletely understood. We investigated how prolonged interleukin-1β (IL-1β) stimulation remodels the chondrocyte proteome and whether these changes are associated with senescence-associated traits. Primary human articular chondrocytes were exposed to IL-1β (10 ng/mL) for up to four days. Time-resolved data-independent acquisition (DIA) proteomics was integrated with immunofluorescence, quantitative PCR, multiplex metalloproteinase profiling, BrdU incorporation, growth-curve analysis, and senescence-associated β-galactosidase assays. Sustained IL-1β induced extensive time-dependent proteomic remodeling, with early inflammatory and extracellular matrix responses followed by alterations in cell-cycle regulation and cytoskeletal organization. Prolonged stimulation was associated with persistent downregulation of CDK4, Cyclin D1, DNA replication-associated proteins, and Rho GTPase-associated components, accompanied by actin cytoskeletal remodeling. These molecular changes were associated with impaired proliferation, increased senescence-associated β-galactosidase activity, and transient modulation of p21. Following cytokine withdrawal, BrdU incorporation showed partial recovery. Together, these findings indicate that sustained IL-1β progressively reshapes the chondrocyte cellular state through coordinated remodeling of proliferative, cytoskeletal, and metalloprotease programs while showing some degree of proliferative plasticity under the conditions tested.