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

Abstract

Lipid droplets (LDs) are dynamic organelles involved in metabolic regulation and cellular stress responses, yet their biochemical heterogeneity and treatment-dependent remodeling in the context of radiotherapy remain poorly understood. Here, we present the first label-free Raman spectroscopic analysis of isolated lipid droplets (iLDs) from normal Schwann cells and malignant peripheral nerve sheath tumor (MPNST) cells subjected to cannabidiol (CBD) treatment, ionizing radiation, and their combination. Raman spectroscopy revealed pronounced chemical heterogeneity of iLDs both between and within cell types, reflecting differences in acyl chain organization, conformational order, and lipid class composition. CBD treatment induced substantial lipid remodeling in Schwann cells, giving rise to multiple iLD subpopulations, whereas MPNST cells exhibited a more constrained response. Irradiation altered lipid droplet heterogeneity in a cell-type-dependent manner, while combined CBD treatment and irradiation induced characteristic alterations in LD cargo that differed markedly between Schwann and MPNST cells, highlighting lipid droplets as sensitive reporters of metabolic reprogramming and stress adaptation. Overall, these findings establish Raman-based lipid droplet profiling as a powerful approach for resolving treatment-specific metabolic remodeling at the suborganelle level and provide new insight into lipid-mediated mechanisms underlying radiosensitization in cancer cells.