Activated Tissue-Resident Mesenchymal Stromal Cells Regulate Natural Killer Cell Immune and Tissue-Regenerative...

Area of Science:

• Immunology
• Cell Biology
• Tissue Engineering

Background:

• Mesenchymal stromal cells (MSCs) traditionally inhibit natural killer (NK) cell effector functions.
• The dynamic interaction between MSCs and NK cells in infection or injury is not fully understood.

Purpose of the Study:

• To investigate the time-dependent regulation of NK cell activity by MSCs in a dynamic in vitro model.
• To elucidate the feedback mechanisms between MSCs and NK cells during immune responses.

Main Methods:

• Utilized a dynamic in vitro system with poly(I:C) stimulation to model MSC-NK cell interactions.
• Analyzed the secretion of cytokines (Type I interferon, TGF-β, IL-6) by MSCs at different time points.
• Assessed the impact of MSC-derived factors on NK cell effector function and phenotype.

Main Results:

• Activated MSCs initially enhance NK cell function via Type I interferon secretion.
• Later, MSCs induce a regulatory, senescent-like NK cell phenotype using TGF-β and IL-6, limiting inflammation.
• Regulatory NK cells promote MSC survival, proliferation, and pro-angiogenic properties.

Conclusions:

• MSC-NK cell interaction is a time-dependent, dynamic process, not a static inhibitory one.
• MSCs exhibit time-dependent polarization and licensing, influencing innate immune responses.
• This study offers new insights into stromal cell and innate immune cell crosstalk.