Simulated microgravity modulates the mesenchymal stromal cell response to inflammatory stimulation

Area of Science:

• Space biology
• Cellular biology
• Biomedical engineering

Background:

• Manned space flights necessitate understanding microgravity's effects on human physiology.
• Mesenchymal stem cells (MSCs) play a crucial role in tissue repair and remodeling.
• Inflammatory activation is a key trigger for MSC engagement in reparative processes.

Purpose of the Study:

• To investigate the impact of simulated microgravity (sµg) on TNFα-mediated priming of adipose tissue-derived MSCs (ASCs).
• To assess changes in inflammatory markers, cytokine production, and gene expression in ASCs under sµg.
• To determine the time course of these effects during simulated microgravity exposure.

Main Methods:

• Adipose tissue-derived MSCs (ASCs) were subjected to simulated microgravity using 3D-clinorotation.
• ASCs were primed with TNFα under both normal and simulated microgravity conditions.
• Analysis included ICAM-1 and HLA-ABC expression, soluble mediator production, transcription profiling, and gene expression of growth factors and cytokines.

Main Results:

• Simulated microgravity alone did not induce inflammatory changes in ASCs.
• ASCs exposed to sµg showed an attenuated response to TNFα priming.
• This attenuation included decreased production of TNFα-dependent cytokines (IL-8, MCP-1) and matrix remodeling proteases, along with gene downregulation.

Conclusions:

• Simulated microgravity impairs the inflammatory priming of ASCs.
• The reduced responsiveness of MSCs to priming under sµg could hinder their role in tissue remodeling during spaceflight.
• Further research is needed to understand the long-term implications for astronaut health and recovery.