Authors: Latha M Malaiyandi Harsh Sharthiya Kirk E Dineley
Publish Date: 2016/06/03
Volume: 29, Issue: 4, Pages: 625-635
Abstract
Leadmium Green is a commercially available small molecule fluorescent probe advertised as a detector of free intracellular cadmium Cd2+ and lead Pb2+ Leadmium Green has been used in various paradigms such as tracking Cd2+ sequestration in plant cells heavy metal export in protozoa and Pb2+ absorption by vascular endothelial cells However very little information is available regarding its affinity and selectivity for Cd2+ Pb2+ and other metals We evaluated the in vitro selectivity of Leadmium Green using spectrofluorimetry Consistent with manufacturer’s claims Leadmium Green was sensitive to Cd2+ KD ~600 nM and also Pb2+ KD ~90 nM in a concentrationdependent manner and furthermore proved insensitive to Ca2+ Co2+ Mn2+ and Ni2+ Leadmium Green also responded to Zn2+ with a KD of ~82 nM Using fluorescence microscopy we evaluated Leadmium Green in live mouse hippocampal HT22 cells We demonstrated that Leadmium Green detected ionophoremediated acute elevations of Cd2+ or Zn2+ in a concentrationdependent manner However the maximum fluorescence produced by ionophoredelivered Zn2+ was much less than that produced by Cd2+ When tested in a model of oxidantinduced liberation of endogenous Zn2+ Leadmium Green responded weakly We conclude that Leadmium Green is an effective probe for monitoring intracellular Cd2+ particularly in models where Cd2+ accumulates rapidly and when concomitant fluctuations of intracellular Zn2+ are minimal
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