The Secretome Derived From Serum-Free Media of SHED-MSCs Can Modulate THP-1-Derived Macrophage Cells

Although culturing cells in serum-free or low-serum media may lead to reduced cell proliferation, it is crucial to minimise the presence of foreign proteins and other impurities that could compromise the validity of experimental findings on immunomodulation. The study aimed to investigate the immunomodulatory effects of the secretome derived from the serum-free media (SFM) of stem cells obtained from human exfoliated deciduous teeth on THP-1-derived macrophage polarisation and the assessment of inflammatory and oxidative stress mediators. THP-1 cells were polarised into M0 and M1 macrophages, and their differentiation was confirmed using flow cytometry to analyse specific markers of M0 (CD14 and CD68) and M1 (CD80 and CD86). The secretome was collected from SHED-MSCs cultured for 48 h in serum-free DMEM/F12 media. After treating THP-1-derived M0/M1 macrophages with SFM-secretome from SHED-MSCs, cells and supernatants were evaluated for immunosuppressive (anti-inflammatory and antioxidant) and immunostimulatory (pro-inflammatory and pro-oxidant) indicators. Secretome treatment decreased the population of M1 macrophages, along with the expression of pro-inflammatory and pro-oxidative markers, including CD80, CD86, TNF-α, IL-12, NO, MDA and IL-6R. The immunomodulatory effect of the secretome produced by SFM, which may help reduce inflammation, is demonstrated by an increase in M2 macrophages and anti-inflammatory and antioxidant markers, including CD206, TGFβ-2, IL-10, TAC, CAT, SOD and ARG1. The secretome produced by SFM-derived SHED-MSCs may reduce the risk of introducing foreign proteins and other potentially hazardous chemicals and enhance the efficacy of cellular secretions for applications such as immunotherapy or regenerative medicine by modulating the immune system.