Transcriptomic Evidence for EGCG-Induced Immune Activation in Microglia

Introduction: Epigallocatechin gallate (EGCG), a polyphenol abundant in green tea, possesses well-documented immunomodulatory and neuroprotective activities; however, its precise transcriptional impact on microglial immune responses remains poorly characterized. In this study, we conducted an in silico transcriptomic analysis of publicly available RNA-seq data (GSE208144) to characterize gene-expression changes in microglia after EGCG exposure. Methods: Heat-map and bar-plot analyses of cytokine profiles revealed significant up-regulation of pro-inflammatory mediators, including Il1b, Tnf, and Cxcl10. Principal component analysis (PCA) and MA plots demonstrated clear segregation of EGCG-treated samples from controls. Results: Functional enrichment analysis of differentially expressed genes indicated over-representation of KEGG pathways related to cytokine–cytokine receptor interaction, chemokine signalling, and Toll-like receptor signalling. STRING-network interrogation of immune-related genes highlighted an EGCG-induced immune-activation signature. In addition, targeted analysis revealed a modest yet reproducible up-regulation of canonical EGCG-responsive genes, including Il6, Bcl2, and Pten. Conclusion: Collectively, these findings support a model in which EGCG primes microglia toward a pro-inflammatory phenotype, thereby potentially enhancing neuro-immune surveillance. The present work offers a systems-level perspective on the immunomodulatory actions of EGCG in primary brain-resident macrophages under steady-state conditions and underscores the utility of transcriptomic data mining for assessing nutraceutical bioactivity.