Functional interleukin-4 releasing microparticles impact THP-1 differentiated macrophage phenotype

Area of Science:

• Biomaterials Science
• Immunology
• Drug Delivery

Background:

• Macrophage cell therapies show promise for inflammatory diseases, but require sustained pro-regenerative phenotypes in vivo.
• Polymeric microparticles offer a method to control and maintain desired macrophage phenotypes.
• Interleukin-4 (IL-4) is crucial for in vitro induction of the M2a macrophage phenotype.

Purpose of the Study:

• To design and evaluate IL-4-encapsulated microparticles for controlled drug release.
• To develop and utilize a THP-1 cell assay for assessing functional IL-4 release and macrophage phenotype modulation.
• To investigate the impact of microparticle drug release kinetics on macrophage immunomodulation.

Main Methods:

• Microparticles were fabricated using PLGA and PLGA-PEG-PLGA triblock copolymers encapsulating IL-4 and human serum albumin (HSA).
• IL-4 and HSA release kinetics were quantified using ELISAs.
• THP-1 differentiated macrophages were exposed to microparticles (direct or transwell) and assessed for immunomodulatory effects via ELISA and qPCR.

Main Results:

• IL-4 release from microparticles followed first-order kinetics, indicating concentration-dependent release.
• The developed microparticles effectively modulated THP-1 differentiated macrophages towards pro-immunoregulatory phenotypes.
• The study established a robust in vitro assay for evaluating macrophage phenotype modulation.

Conclusions:

• IL-4 encapsulated microparticles provide a viable drug delivery system for modulating macrophage phenotype.
• This approach enables in vitro assessment of macrophage responses to inform targeted therapies for inflammation and immune modulation.
• The controlled release strategy is a significant advancement in developing novel drug carriers for immune-related conditions.