Kinetics of MSC-based enzyme therapy for immunoregulation

Area of Science:

• Immunology
• Cell Biology
• Biochemistry

Background:

• Mesenchymal stromal cells (MSCs) possess immunomodulatory properties, making them promising for cell therapy.
• Their therapeutic mechanisms, particularly in vivo dosing and duration, require further investigation.
• MSCs rapidly suppress inflammation via ectoenzymes CD73 and CD39, converting extracellular adenosine triphosphate (ATP) to anti-inflammatory adenosine.

Purpose of the Study:

• To quantitatively analyze the effect of MSCs on adenosine triphosphate (ATP) hydrolysis in immune cell responses.
• To determine the kinetic parameters of ATP hydrolysis by MSCs.
• To validate the ability of MSCs to modulate inflammatory signaling pathways.

Main Methods:

• In vitro experiments to determine ATP hydrolysis rates by MSCs.
• Kinetic modeling to establish the rate of ATP metabolism per cell.
• Co-culture of MSCs with immune cells (lymphocytes and monocytes) using transwell inserts to assess inflammatory responses.

Main Results:

• ATP hydrolysis by MSCs was efficiently modeled using first-order enzyme kinetics.
• The rate of ATP hydrolysis per MSC was determined to be 8.9 nmol/min in vitro.
• MSC co-cultures reduced lymphocyte cytotoxicity, promoted proliferation, and limited IL-1β secretion from monocytes in the presence of extracellular ATP.

Conclusions:

• This study provides the first quantitative, cell-molecule basis for MSCs' effect on ATP hydrolysis in immune responses.
• The findings offer insights into MSCs' dynamic regulatory mechanisms for ameliorating extracellular ATP effects.
• The developed models can aid in predicting optimal MSC dosing for treating chronic inflammatory diseases.