The over-expression of TRPC6 channels in HEK-293 cells favours the intracellular accumulation of zinc

Abstract

TRPC6 are plasma membrane cation channels. By means of live-cell imaging and spectroscopic methods, we found that HEK cells expressing TRPC6 channels (HEK-TRPC6) are enriched in zinc and sulphur and have a reduced copper content when compared to HEK cells and HEK cells expressing TRPC3 channels (HEK-TRPC3). Hence, HEK-TRPC6 cells have larger pools of mobilizable Zn2+ and are more sensitive to an oxidative stress. Synchrotron X-ray fluorescence experiments showed a higher zinc content in the nuclear region indicating that the intracellular distribution of this metal was influenced by the over-expression of TRPC6 channels. Their properties were investigated with the diacylglycerol analogue SAG and the plant extract hyperforin. Electrophysiological recordings and imaging experiments with the fluorescent Zn2+ probe FluoZin-3 demonstrated that TRPC6 channels form Zn2+-conducting channels. In cortical neurons, hyperforin-sensitive channels co-exist with voltage-gated channels, AMPA and NMDA receptors, which are known to transport Zn2+. The ability of these channels to regulate the size of the mobilizable pools of Zn2+ was compared. The data collected indicate that the entry of Zn2+ through TRPC6 channels can up-regulate the size of the DTDP-sensitive pool of Zn2+. By showing that TRPC6 channels constitute a Zn2+ entry pathway, our study suggests that they could play a role in zinc homeostasis.

Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine

“…It is only at very negative potentials that Ca 2+ entry through TRPC6 becomes significant (Estacion et al, 2006). TRPC6 is also a Zn 2+ -permeable channel (Gibon et al, 2011). With regard to its functional impact, TRPC6 has been identified as an important player in dendritic growth, neuronal survival, and synapse formation (Jia et al, 2007;Zhou et al, 2008).…”

Multiple clinical forms of dehydrated hereditary stomatocytosis arise from mutations in PIEZO1

“…[31][32][33][34] cRNA was injected in a volume of 50 nL, and oocytes were maintained at 17°C for 72 hours prior to experimentation. Defolliculated oocytes were placed in ND96 (in mM, 96 NaCl, 2 KCl, 1.8 CaCl 2 , 1 MgCl 2 , 5 HEPES [N-2-hydroxyethylpiperazine-N9-2-ethanesulfonic acid], pH 7.4) in a bath (RC-16; Warner Instruments, Hamden, CT) on the headstage of an upright microscope and imaged at 320 magnification.…”

Synthetic Metallochaperone ZMC1 Rescues Mutant p53 Conformation by Transporting Zinc into Cells as an Ionophore

“…We evaluated the ability of ZMC1, NTA (Zn 21 -binding homolog), and A6 (structural homolog) to increase intracellular [Zn 21 ] free by treating cells with the fluorescent Zn 21 indicator FZ3-AM in complete media and imaging them using confocal microscopy ( Fig. 1B) (Gibon et al, 2011). In both HEK293 (non-cancer, p53-WT) and TOV112D (ovarian cancer, p53-R175H) cells, ZMC1 increased intracellular [Zn 21 ] free as indicated by increased fluorescence, but NTA and A6 did not.…”