Lipid droplet–mitochondria contact sites as druggable spatial-pharmacology targets in respiratory disease: cross–cell-type mechanisms and translational strategies

Lipid droplets and mitochondria form regulated contact sites whose molecular composition, phosphorylation state and spatial geometry now behave as measurable, druggable variables in living cells. The molecular toolkit has been mapped in liver, muscle and adipose tissue, yet its application to respiratory disease has lagged despite a lung-specific dependence on lipid biology that spans surfactant biogenesis, alveolar-macrophage lipid handling and fibroblast-driven remodelling. This review argues that the lipid-droplet–mitochondria contact site is an emerging spatial-pharmacology target in respiratory medicine, and organises the evidence into a three-way matrix with explicit grading of direct, indirect and cross-tissue evidence. A common molecular toolkit built around perilipin-family scaffolds, mitochondrial-outer-membrane tethers, an endoplasmic-reticulum bridging apparatus and the PFKL–PLIN2–CPT1A flux node (mechanistically established in hepatocellular carcinoma and inferred in lung) is rewired into cell-type-specific configurations across alveolar type 2 cells, macrophages, fibroblasts, endothelium and lung adenocarcinoma. That toolkit acquires a distinct disease role across idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, asthma, acute respiratory distress syndrome, tuberculosis, severe acute respiratory syndrome coronavirus two infection and lung cancer, generating a matrix of cell-type-by-disease configurations that no prior review has systematized. Four target axes, namely, tether occupancy, lipid flux, redox coupling and cell-type-precise delivery, converge geometrically at the interface and motivate combination strategies rather than pan-mitochondrial single-agent approaches. Inhaled lipid nanoparticles, mucus-penetrating carriers and engineered extracellular vesicles bring these targets within reach with cell-type precision. Endothelial contact-site biology is identified as the largest evidence gap and discussed candidly. The framework is offered as a roadmap for tether-axis compound development, contact-site engagement biomarkers and dual-axis inhaled therapeutics.