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Photoactivatable Exosenolytics Activate Natural Killer Cells for Delaying Osteoarthritis

Lei Zhang1,2, Kai Xiang1, Jinlong Li1

  • 1School of Pharmacy, Wannan Medical College, Wuhu 241002, China.

ACS Nano
|June 19, 2025
PubMed

Insights

This study introduces exosenolytics, a novel therapy for osteoarthritis (OA) that uses light-activated exosomes to clear aging cells and reduce joint inflammation. This approach enhances immune cell activity for effective aging immunotherapy.

Area of Science:

  • Immunology
  • Biotechnology
  • Gerontology

Background:

  • Osteoarthritis (OA) progression correlates with increased senescent cells in joint synovium.
  • Current senolytics face limitations due to off-target toxicity.
  • Immune-mediated clearance of senescent cells is a potential therapeutic strategy, but is often impaired by immunosuppressive microenvironments.

Purpose of the Study:

  • To develop photoactivatable exosenolytics for precise anti-aging treatment of OA.
  • To enhance immune-mediated clearance of senescent cells in the context of OA.
  • To investigate the therapeutic potential of exosenolytics in remodeling the senescent immune microenvironment.

Main Methods:

  • Construction of exosenolytics from macrophage-derived exosomes, functionalized with aPD-L1 and aging cell-targeting ligands.
  • Encapsulation of a photosensitizer and NKG2D ligand activator within the exosomes.
  • Evaluation of exosenolytic efficacy in OA mouse models, assessing immune cell recruitment, senescent cell clearance, and OA progression.

Main Results:

  • Exosenolytics selectively accumulated in senescent fibroblast-like synoviocytes in inflamed OA joints.
  • Exosenolytic-mediated photodynamic therapy induced natural killer (NK) cell recruitment and enhanced their interaction with senescent cells.
  • The therapy activated the cGAS-STING pathway, strengthening immune clearance of senescent synovial cells and suppressing inflammation and OA progression.

Conclusions:

  • Exosenolytics offer a precise anti-aging treatment for OA by leveraging photodynamic therapy and immune system activation.
  • This approach effectively remodels the senescent immune microenvironment, overcoming immunosuppression.
  • Exosenolytics represent a promising new strategy for aging immunotherapy in OA treatment.
Keywords:
GAS-STING pathwayexosenolyticsimmunotherapynatural killer cellsosteoarthritissenescent fibroblast-like synoviocytes

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