Dados do Trabalho

Título/Title/Titulo

Membrane particles of mesenchymal stem cells and conditioned medium polarizes macrophages in vitro to an anti-inflammatory phenotype

Introdução/Introduction/Introdución

The immunomodulatory properties of mesenchymal stem cells (MSC) have been extensively studied over recent years. It is believed that these cells can induce immune cells, such as macrophages, from a pro-inflammatory profile (M1) to an anti-inflammatory profile (M2). In this way basic and clinical studies have demonstrated the effect of MCS cell therapy to treat inflammatory conditions. However, there are controversial studies about the location, the persistence and the risks of MSC transplantation. Tracking studies have shown that most MSCs are trapped in the lungs due to their size and have a short-term survival in the body after intravenous infusion. In addition, after 24 hours of infusion, MSCs tend to disappear from the lungs suggesting that these cells pass their effects to resident cells. In order to increase the biodistribution of the therapeutic effect of MSC, avoiding cellular entrapment in pulmonary capillaries, as well as providing safer therapy based on MSC potential our research group is studying alternative cell therapies such as the use of bioactive factors secreted by MSC (MSC-BF) and the generation of membrane particles from MSC (MSC-MP).

Objetivos - Metodologia - Resultados - Discussão dos Resultados/Objectives - Methodology - Results - Discussion of Results/Objetivos - Metodología - Resultados - Discusión de los resultados

Objectives: To evaluate the immunomodulatory effects of MSC-BF and MSC-MP on the polarization of murine macrophages.
Methods: C57BL/6 male mice were used to collect mesenchymal stem cells from epididymal adipose tissue and peritoneal macrophages to perform cell cultures. After culture and expansion of the MSC, these cells were stimulated with LPS, and their conditioned medium (MSC-BF) was collected. Particles from MSC plasmatic membrane were generated by cell lysis and ultracentrifugation, and their size were analyzed by Nanoparticle Tracking Analysis (NanoSight NS300). The peritoneal macrophages were stimulated with LPS (pro-inflammatory environment control) and IL-4 (anti-inflammatory environment control) and co-cultured with MSC, MSC-MP and MSC-BF to evaluate the macrophage polarization. The cultures were evaluated for CD206 marker by flow cytometry (anti-inflammatory macrophage marker).
Results and Discussion: Nanoparticle Tracking Analysis shown that the majority of MSC-MPs demonstrated a size of 114nm. Macrophages CD206 expression revealed different results based on the co-culture condition: MSC (MFI= 6.195), MSC-MP (MFI= 4.582) or MSC-BF (MFI= 4.066) indicating that cell-cell contact potentiate the effects of cell culture.

Considerações Finais/Final considerations/Consideraciones finales

With regards to these preliminary results we can conclude that membrane interaction promoted better macrophage polarization into an anti-inflammatory profile in vitro instead of the use of bioactive factors. We can also suggest the feasibility of the membrane particles application to promote the interaction with macrophages.

Palavras-chave/Key words/Palabras clave

Mesenchymal stem cells; macrophage polarization; membrane particles; immunomodulation