Analysis of distribution and function of peroxisomes in redox and lipid homeostasis in Drosophila embryogenesis

Abstract

Peroxisomes are dynamic organelles essential for lipid metabolism and reactive oxygen species (ROS) homeostasis, yet their spatiotemporal regulation during rapid developmental transitions remains poorly understood. Here, we characterize peroxisome behavior during epithelial cell formation in the cellularization during embryonic development in Drosophila. Our results demonstrate that peroxisomes undergo a coordinated basal-to-apical translocation, becoming predominantly apically populated by the end of cellularization. Furthermore, embryos carrying a mutation in the dynamin related protein, Drp1, which is known to play a role in peroxisome and mitochondrial fission, exhibit a significantly reduced number of peroxisomes. This is in accordance with the basal accumulation of mitochondria in Drp1 mutants as previously reported. Besides, knockdown of mitochondrial Superoxide Dismutase 2 (SOD2) leads to the aberrant retention of peroxisomes in basal regions, while co-depletion of Drp1 and SOD2 further diminishes peroxisome abundance. We also demonstrate that peroxisome maintenance during this stage relies on the classical biogenesis factors PEX3 and PEX19, as their knockdown leads to a sharp decline in organelle number that persists even in the absence of Drp1. Finally, we show that disruption of Drp1 or SOD2 leads to an accumulation of lipid droplets, suggesting that impaired peroxisome dynamics and abundance disrupt neutral lipid processing. Together, our findings reveal an interplay between Drp1, mitochondrial and peroxisomal fission, antioxidant defense, and peroxisome biogenesis in governing organelle distribution and metabolic homeostasis during early development.