Piperine-primed rat mesenchymal stem cells’ secretome promotes an anti-inflammatory phenotype in the J774.1 murine macrophage cell line

Preconditioning mesenchymal stem cells (MSCs) with small molecules is a promising strategy to enhance their therapeutic efficacy. This study investigated piperine, a bioactive alkaloid from black pepper with known immunomodulatory properties, as a novel priming agent. We aimed to evaluate the immunomodulatory effect of the secretome from piperine-primed MSCs on the modulation of macrophage function. J774.1 murine macrophages were stimulated with lipopolysaccharide (LPS) and then treated with either piperine (10, 20, or 40 µM) or conditioned medium (CM) from rat bone marrow-derived MSCs. The MSCs were cultured with or without piperine priming (10, 20, or 40 µM). Modulation of macrophage function was assessed by quantifying the mRNA expression of M1- and M2-related markers via qPCR. Nitric oxide (NO) production was measured using the Griess assay. Preconditioning MSCs with 10 µM piperine generated a secretome that significantly shifted macrophages toward an anti-inflammatory phenotype. This shift was evidenced by the upregulated expression of IDO1, TGF-β, and IL-10 mRNA and a concurrent reduction in NO production, effects that were more pronounced than with piperine or standard MSC-CM alone. Piperine preconditioning synergistically enhances the immunomodulatory capacity of the MSC secretome, promoting a potent anti-inflammatory macrophage profile. This cell-free strategy, leveraging a natural compound to augment MSC function, presents a promising therapeutic approach for inflammatory diseases.