ApAGP-fabricated silver nanoparticles induce amendment of murine macrophage polarization

M2 polarization of macrophages is predominant in case of tumors and some other infectious diseases for disease progression. Repolarization of the M2 phenotype to the M1 state may be required to cure diseases. Hence, it is of great interest to find out a material that would repolarize the M2 phenotype to the M1 state. Herein, the arabinogalactan protein from Andrographis paniculata (ApAGP) was used to prepare a silver nanoparticle-ApAGP (SNP-ApAGP) bioconjugate, which was characterized via UV-vis spectroscopy, zeta potential analysis, FT-IR spectroscopy, and HR-TEM. Studies suggest that SNP-ApAGP (2.5 μg mL^-1) up-regulates ROS generation, NO generation, and pro-inflammatory cytokine release (IL-12, IFN-γ, TNF-α, and IL-6). SNP-ApAGP also down-regulates the arginase-1 activity and anti-inflammatory cytokine release (IL-4 & IL-10) in M0, M1, and M2-polarized peritoneal macrophages in vitro. Therefore, SNP-ApAGP induces M1 polarization in M0 macrophages, enhances the pro-inflammatory activity of the M1 phenotype, and can also repolarize M2 macrophages into the M1 phenotype. Therefore, SNP-ApAGP could be used for treating various infectious diseases and cancers where repolarization of M2 macrophages may be required to cure the disease.