Genomic Stress and DNA Repair During Macrophage Differentiation and Inflammatory Activation.

Macrophages must preserve genome stability while performing immune and tissue-supporting functions that can themselves induce DNA damage or interfere with genome maintenance. Inflammatory metabolism produces reactive oxygen and nitrogen species, extensive transcription imposes topological and transcription-associated stress, and proliferative responses generate replication stress. At the same time, studies of monocyte-derived macrophages and macrophage-like differentiation models show selective changes in DNA repair capacity: base excision repair (BER)/single-strand break (SSB) repair and DNA-dependent protein kinase (DNA-PK)-dependent double-strand break (DSB) repair are enhanced, whereas global nucleotide excision repair (NER) can be attenuated while repair is preferentially retained in transcriptionally active regions. When these protective mechanisms fail, persistent DNA damage can promote apoptosis or senescence, alter inflammatory signaling and extracellular communication, and modify self-antigen presentation. Here, we focus on differentiation-associated changes in DNA repair capacity and genome maintenance during inflammatory activation, drawing on selected tissue and disease models. We also discuss emerging evidence that circadian regulation of metabolism and redox activity may add a temporal dimension to this balance. Defining how pathway-specific DNA repair capacity is matched to state-dependent genotoxic challenges will clarify how genome stability supports immune homeostasis and how its disruption contributes to inflammatory dysfunction.