Organelles coordinate milk production and secretion during lactation: Insights into mammary pathologies. (April 2022) - Dai, Wenting
Abstract: The mammary gland undergoes a spectacular series of changes during its development and maintains a remarkable capacity to remodel and regenerate during progression through the lactation cycle. This flexibility of the mammary gland requires coordination of multiple processes including cell proliferation, differentiation, regeneration, stress response, immune activity, and metabolic changes under the control of diverse cellular and hormonal signaling pathways. The lactating mammary epithelium orchestrates synthesis and apical secretion of macromolecules including milk lipids, milk proteins, and lactose as well as other minor nutrients that constitute milk. Knowledge about the subcellular compartmentalization of these metabolic and signaling events, as they relate to milk production and secretion during lactation, is expanding. Here we review how major organelles (endoplasmic reticulum, Golgi apparatus, mitochondrion, lysosome, and exosome) within mammary epithelial cells collaborate to initiate, mediate, and maintain lactation, and how study of these organelles provides insight into options to maintain mammary/breast health. Highlights: Endoplasmic reticulum coordinates the synthesis and secretion of milk constituents. Golgi acts as a subcellular site for the formation and secretion of milk constituents. Mitochondria regulate energy homeostasis, stress response and redox regulation. Exosomes influence milk lipid metabolism through interaction with miRNAs. Multiple organelles orchestrate milk lipid droplets formation, trafficking and secretion.