Characterization of lipid droplets dynamics during adipocytes metabolism

Lipid droplets (LDs) are organelles that play a role in energy metabolism through their ability to accumulate and store lipids. The primary lipid pool resides in adipose tissue adipocytes, and these cells are specialized in their ability to generate and store energy as triglycerides in the form of LDs. Upon stimulation, catalytic lipolytic enzymes break the LD down to provide an energy substrate in times of need. This process is a key in maintaining the needed balance in lipid homeostasis, which is crucial for systemic metabolism. In this study, we examined the LD’s dynamics during their breakdown and characterized microtubule polymerization during the process. First, we analyzed the size of LDs over time in differentiated adipocytes and their correlation with other morphological parameters. The LDs were examined for their dynamics during lipolysis and lipophagy, and different subpopulations of adipocytes and LDs were identified based on their structural, numerical, and spatial variability. Lipolytic induction was found to affect the cell’s morphology, which pointed towards the involvement of cytoskeletal dynamics and remodeling as part of the lipolysis procedure. Moreover, we tracked and characterized the motility of LDs during lipolysis, shedding light on their orchestrated movement mediated by the cytoskeleton. LDs movement in lipolysis was tubulin-dependent as inhibition of microtubule dynamics resulted in significantly reduced movement and slower shrinkage rate. Our results emphasized the different LD-related metabolic conditions and shed light on the dynamic nature and the spatial complexity of LD metabolism.