Fueling the sentinels: organelle remodeling and metabolic adaptation in tissue-resident memory T cell persistence.

Tissue-resident memory T (TRM) cells persist at barrier and parenchymal sites where oxygen, nutrients, and inflammatory signals fluctuate. Their durability therefore cannot be explained by tissue retention alone. Evidence from skin, liver, intestine, lung, tumors, and inflamed tissues supports a coupled program in which local nutrient capture, mitochondrial fuel selection, organelle dynamics, autophagy, mitophagy, and proteostatic responses sustain survival while preserving rapid effector competence. We propose "organelle-niche matching" as a testable four-step working model: tissue inputs engage nutrient-, oxygen-, danger-, cytokine-, and antigen-sensing pathways; these regulate mitochondrial biogenesis, fusion-fission balance, respiratory-chain organization, and selective turnover; organelle state controls bioenergetic reserve, redox balance, apoptosis, and metabolite availability; and these outputs may reinforce or destabilize transcriptional residency and recall. The model integrates evidence across contexts, not one pathway established in a single TRM population. Direct TRM evidence is distinguished from tumor-infiltrating lymphocyte data and extrapolation from conventional memory CD8+ T cells. Lipid uptake and fatty-acid oxidation are prominent in selected TRM niches but are not universal, and mitophagy should not be equated with mitochondrial health. This framework identifies causal links already demonstrated in TRM cells, relationships that remain correlative, and therapeutic opportunities to strengthen protective residents without sustaining pathogenic populations.