The Role of Pattern Recognition Receptors in Epigenetic and Metabolic Reprogramming: Insights into Trained Immunity

Pattern recognition receptors (PRRs) function as pivotal components of the innate immune system by orchestrating trained immunity through dynamic epigenetic and metabolic reprogramming. Recent discoveries demonstrate that PRRs not only detect pathogens but also actively regulate immune cell metabolism and transcriptional landscapes, thereby potentiating the speed and magnitude of defensive responses upon secondary challenges. These functional adaptations are coordinated through evolutionarily conserved signaling cascades that establish persistent immunological modifications at cellular and systemic levels. Nevertheless, despite substantial advances in characterizing PRR-driven immune activation, the molecular mechanisms governing their role in innate immune memory formation remain incompletely elucidated. This review systematically explores emerging paradigms of PRR-mediated epigenetic remodeling and metabolic rewiring, with particular emphasis on their mechanistic integration into trained immunity. We critically assess current evidence, identify unresolved questions regarding signal transduction specificity and memory maintenance, and propose novel methodological approaches to decipher the multilayered regulatory networks of innate immune adaptation. By elucidating these processes, our analysis establishes a conceptual framework for developing immunomodulatory therapies and leveraging trained immunity in precision medicine applications.