Integrated transcriptomic and epigenomic analysis demonstrates apple mango leaf extract induced maturation and functional activation of BMDCs
The apple mango (Mangifera indica L.) is primarily consumed for its fruit, and the other components of the plant, including the leaves, are often discarded as agricultural by-products. This study investigated the immunomodulatory properties of apple mango leaf extract (AMLE) using transcriptomic and chromatin accessibility analyses, focusing on gene regulation and signaling pathways in bone marrow-derived dendritic cells (BMDCs). Weighted gene co-expression network analysis (WGCNA) revealed two inversely regulated gene network modules. The upregulated module following AMLE treatment included pathways essential for dendritic cell (DC) activation, while the downregulated module was enriched in cell cycle and metabolic pathways. Assay for Transposase Accessible Chromatin with Sequencing (ATAC-seq) analysis revealed increased promoter accessibility in AMLE-treated BMDCs, suggesting increased transcriptional activity. By integrating RNA-seq and ATAC-seq data, we identified 33 commonly regulated genes, with 25 upregulated genes forming a protein-protein interaction network centered on IL1b. These genes were associated with pathways related to cytokine signaling, T cell differentiation and extracellular matrix interactions. AMLE treatment enhanced DC chemotaxis, antigen presentation and promoted T cell differentiation signaling. Specifically, flow cytometric analysis shows that AMLE increased the expression of major histocompatibility complex class II (MHCII) and the co-stimulatory molecules CD40 and CD80, leading to BMDC maturation and expansion of the CD11c+MHCIIhi and CD11c+CD11blo subsets. These findings suggest that AMLE induces potent maturation responses through multiple pathways within DC subpopulations. By elucidating the transcriptional and epigenetic effects of AMLE on BMDCs, this study contributes to a broader understanding of plant-derived compounds in immune modulation. Overall design: RNA and ATAC sequencing of bone marrow-derived dendritic cells (BMDCs) from female C57BL/6 mice (8-10 weeks old) were cultured in cRPMI medium (RPMI 1640 supplemented with 10% FBS, 1% penicillin/streptomycin, 50 µM 2-mercaptoethanol and 20 ng/mL GM-CSF) for 7 days. Non-adherent cells were collected as immature BMDCs on day 6, treated with AMLE (400 µg/mL) or 0.04% DMSO for 24 hours and used for next-generation sequencing.