Interleukin-1 Receptor Antagonist (IL-1RA) Mediates Age-Dependent Immunoregulation of Adipose-Derived Stem Cells via Macrophage Polarization

This study aimed to clarify whether interleukin-1 receptor antagonist (IL-1RA) mediates the age-dependent immunomodulatory capacity of adipose-derived stem cells (ASCs) via regulating macrophage polarization. ASCs from young (Y-ASCs) and aged (O-ASCs) C57BL/6 mice were isolated. IL-1RA, which was identified as an age-sensitive candidate through integrated transcriptomic and proteomic screening in our prior publication, was validated by qPCR, immunofluorescence, and ELISA. RAW264.7 macrophages were polarized and co-cultured with ASCs or treated with recombinant IL-1RA; IL-1RA in Y-ASCs was silenced by siRNA (82.3 ± 5.1% knockdown efficiency). The results showed Y-ASCs had 2.1-fold higher IL-1RA mRNA and significantly higher protein secretion than O-ASCs (p < 0.001). Y-ASC transplantation enhanced M2 polarization (CD206+ cells increased from 9.36% to 21.4% in vivo; p < 0.01) in aged mouse adipose tissue and reduced inflammation (serum IL-1β lowered by 42.3 ± 5.1%; p < 0.001), while O-ASCs had no effect. Recombinant IL-1RA recapitulated Y-ASC effects (M2 macrophages increased from 0.92% to 61.8%; p < 0.001), and IL-1RA silencing abrogated Y-ASC function. The data indicate IL-1RA is a key age-sensitive mediator of ASC immunomodulation. Declined IL-1RA may contribute to impaired aged ASC efficacy, highlighting donor age’s importance. This provides mechanistic insights and guides IL-1RA-targeted optimization for ASC therapies in age-related inflammatory disorders.