ABSTRACT
Insulin-stimulated translocation of glucose transporter 4 (GLUT4) storage vesicles (GSVs), the specialized intracellular compartments within mature adipocytes, to the plasma membrane (PM) is a fundamental cellular process for maintaining glucose homeostasis. Using 2 independent adipocyte cell line models, human primary Simpson-Golabi-Behmel syndrome and mouse 3T3-L1 fibroblast cell lines, we demonstrate that the endosome-associated protein-sorting complex retromer colocalizes with GLUT4 on the GSVs by confocal microscopy in mature adipocytes. By use of both confocal microscopy and differential ultracentrifugation techniques, retromer is redistributed to the PM of mature adipocytes upon insulin stimulation. Furthermore, stable knockdown of the retromer subunit-vacuolar protein-sorting 35, or the retromer-associated protein sorting nexin 27, by lentivirus-delivered small hairpin RNA impaired the adipogenesis process when compared to nonsilence control. The knockdown of retromer decreased peroxisome proliferator activated receptor γ expression during differentiation, generating adipocytes with decreased levels of GSVs, lipid droplet accumulation, and insulin-stimulated glucose uptake. In conclusion, our study demonstrates a role for retromer in the GSV formation and adipogenesis.
Subject(s)
Adipocytes/metabolism , Adipocytes/physiology , Cell Differentiation/physiology , Glucose Transporter Type 4/metabolism , 3T3-L1 Cells , Animals , Arrhythmias, Cardiac/metabolism , Arrhythmias, Cardiac/pathology , Cell Line , Cell Membrane/metabolism , Cell Membrane/physiology , Endosomes/metabolism , Endosomes/physiology , Fibroblasts/metabolism , Fibroblasts/physiology , Gene Knockdown Techniques/methods , Genetic Diseases, X-Linked/metabolism , Genetic Diseases, X-Linked/pathology , Gigantism/metabolism , Gigantism/pathology , Glucose/metabolism , Heart Defects, Congenital/metabolism , Heart Defects, Congenital/pathology , Humans , Insulin/metabolism , Intellectual Disability/metabolism , Intellectual Disability/pathology , Mice , PPAR gamma/metabolism , Protein Transport/physiologyABSTRACT
BRAND's Essence of Chicken (BEC) has been widely used as a traditional remedy by people in Southeast Asia, which is proved to have an effect on the central nervous system (CNS) and autonomic nervous system (ANS). However, whether and how BEC consumption may affect mammalian circadian system is still largely unknown. In the present study, we investigated the effect of BEC feeding on the adaptation of circadian clocks to the experimental jet lag in rats. After the 12-h experimental jet lag through extending the light period, BEC feeding markedly facilitated the re-entrainment of all examined clock genes (Bmal1, Cry1, Per1, and Per2) in the pineal gland. The resetting time course of pineal clock genes was reduced from 7 days to only 3-5 days by BEC feeding, which was almost equal to the effect of melatonin feeding. In the liver clock, the facilitating effect of BEC feeding was mainly displayed in the re-entrainment of Bmal1 and Per2 by shortening their resetting processes for nearly 2 days. However, the resetting rate of locomotor activity rhythm was not affected by BEC feeding, suggesting that BEC might be unable to affect the behavioral rhythm.
