hLMSC Secretome Affects Macrophage Activity Differentially Depending on Lung-Mimetic Environments

Area of Science:

• Biomedical Engineering
• Immunology
• Cell Biology

Background:

• Mesenchymal stromal cell (MSC) therapies for inflammatory diseases leverage their paracrine effects on macrophages.
• Understanding how physiomimetic culture conditions alter MSC secretomes and subsequent macrophage modulation is crucial for therapeutic development.

Purpose of the Study:

• To investigate the impact of lung-mimetic culture conditions on human MSC (hMSC) secretome composition.
• To determine how the altered secretome influences macrophage phagocytosis and M1/M2 polarization.
• To explore the therapeutic potential of mechanically stimulated hMSCs for inflammatory diseases.

Main Methods:

• Human LMSCs (hLMSCs) were cultured in lung-mimetic hydrogel scaffolds (L-Hydrogels) subjected to strain.
• hLMSC secretome was analyzed for cytokine, chemokine, and growth factor content.
• Gene expression of CTGF and CYR61 was assessed.
• Human monocytes were differentiated into macrophages and their phagocytic capacity and M1/M2 subtype markers were analyzed in the presence of hLMSC secretome.

Main Results:

• Culture in L-Hydrogels significantly reduced CTGF and CYR61 expression.
• The hLMSC secretome from lung-mimetic scaffolds showed distinct profiles, with increased HGF and decreased IL-6 and TNF-α compared to 2D cultures.
• Macrophage phagocytosis decreased, M1 populations reduced, and M2b subpopulations increased in the presence of the L-Scaffold secretome.

Conclusions:

• Mechanical properties of the lung extracellular matrix and mechanical strain orchestrate anti-inflammatory and immunosuppressive effects of hLMSCs.
• Physiomimetic culture conditions can tailor hMSC secretomes for enhanced immunomodulatory functions.
• These findings support the development of mechanically tuned hMSC-based therapies for inflammatory conditions.