Lipid droplet isolation as a novel platform for spectroscopic investigation of cargo modifications

Lipid droplets (LDs) are dynamic organelles that coordinate lipid storage, trafficking, and metabolic adaptation under physiological and stress conditions. Despite their emerging role in cellular homeostasis, the molecular basis of treatment-induced lipid droplet remodeling remains insufficiently defined. Here, we combine lipid droplet isolation with label-free Raman spectroscopy to characterize biochemical and spectroscopic signatures associated with structural remodeling of isolated lipid droplets (iLDs) derived from normal Schwann cells and malignant peripheral nerve sheath tumor (MPNST) cells exposed to cannabidiol (CBD), ionizing radiation, and their combination. Our analysis reveals pronounced intrinsic spectral heterogeneity within iLD fractions and identifies treatment- and cell type-specific alterations in lipid composition, Raman spectral markers associated with acyl chain packing, and conformational order. Notably, stress-induced remodeling involves coordinated changes in lipid chain organization, highlighting lipid droplets as dynamic regulators of cellular metabolic adaptation. These findings provide molecular insight into lipid droplet-mediated stress responses and establish Raman-based profiling of isolated LDs as a powerful approach for investigating lipid remodeling mechanisms within isolated lipid droplet-enriched fractions. We further propose the Raman intensity ratio I₁₁₆₇/I₁₂₉₂ as a semiquantitative Raman-derived spectral index associated with stress-induced lipid remodeling and CBD-mediated radiosensitization.