title: Copper modulates the large dense core vesicle secretory pathway in PC12 cells.
abstract: Copper (Cu) is an essential biometal involved in a number of cell functions. Abnormal Cu homeostasis has been identified as a major factor in a number of neurodegenerative disorders. However, little is known about how cells of brain origin maintain Cu homeostasis and in particular, how they respond to an elevated Cu environment. Understanding these processes is essential to obtaining a greater insight into the pathological changes in neurodegeneration and ageing. Although previous studies have shown that Cu in neurons can be associated with synaptic function, there is little understanding of how Cu modulates the regulated secretory vesicle pathways in these cells. In this study, we examined the effect of elevated intracellular Cu on proteins associated with the regulated secretory vesicle pathway in NGF-differentiated PC12 cells that exhibit neuronal-like properties. Increasing intracellular Cu with a cell-permeable Cu-complex (Cu(II)(gtsm)) resulted in increased expression of synaptophysin and robust translocation of this and additional vesicular proteins from synaptic-like microvesicle (SLMV) fractions to chromogranin-containing putative large dense core vesicle (LDCV) fractions in density gradient preparations. The LDCV fractions also contained substantially elevated Cu levels upon treatment of cells with Cu(II)(gtsm). Expression of the H(+) pump, V-ATPase, which is essential for vesicle maturation, was increased in Cu-treated cells while inhibition of V-ATPase prevented translocation of synaptophysin to LDCV fractions. Cu treatment was found to inhibit release of LDCVs in chromaffin cells due to reduced Ca(2+)-mediated vesicle exocytosis. Our findings demonstrate that elevated Cu can modulate LDCV metabolism potentially resulting in sequestration of Cu in this vesicle pool.
authors: Department of Pathology, The University of Melbourne, Victoria 3010, Australia.
authors: Clare
authors: C
authors: Duncan
authors: Laura
authors: L
authors: Bica
authors: Peter J
authors: PJ
authors: Crouch
authors: Aphrodite
authors: A
authors: Caragounis
authors: Grace E
authors: GE
authors: Lidgerwood
authors: Sarah J
authors: SJ
authors: Parker
authors: Jodi
authors: J
authors: Meyerowitz
authors: Irene
authors: I
authors: Volitakis
authors: Jeffrey R
authors: JR
authors: Liddell
authors: Ravinarayan
authors: R
authors: Raghupathi
authors: Brett M
authors: BM
authors: Paterson
authors: Michael D
authors: MD
authors: Duffield
authors: Roberto
authors: R
authors: Cappai
authors: Paul S
authors: PS
authors: Donnelly
authors: Alexandra
authors: A
authors: Grubman
authors: James
authors: J
authors: Camakaris
authors: Damien J
authors: DJ
authors: Keating
authors: Anthony R
authors: AR
authors: White
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003300:Copper / Q000378:metabolism / Q000494:pharmacology*; D016716:PC12 Cells; D051381:Rats; D055571:Secretory Pathway / Q000187:drug effects*; D022142:Secretory Vesicles / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D003300:Copper