posted on 2020-07-29, 20:30authored byGuido Gessner, Philipp Rühl, Matthias Westerhausen, Toshinori Hoshi, Stefan H. Heinemann
Heme
catabolism by heme oxygenase (HO) with a decrease in intracellular
heme concentration and a concomitant local release of CO and Fe2+ has the potential to regulate BKCa channels.
Here, we show that the iron-based photolabile CO-releasing molecule
CORM-S1 [dicarbonyl-bis(cysteamine)iron(II)] coreleases CO and Fe2+, making it a suitable light-triggered source of these downstream
products of HO activity. To investigate the impact of CO, iron, and
cysteamine on BKCa channel activation, human Slo1 (hSlo1)
was expressed in HEK293T cells and studied with electrophysiological
methods. Whereas hSlo1 channels are activated by CO and even more
strongly by Fe2+, Fe3+ and cysteamine possess
only marginal activating potency. Investigation of hSlo1 mutants revealed
that Fe2+ modulates the channels mainly through the Mg2+-dependent activation mechanism. Flash photolysis of CORM-S1
suits for rapid and precise delivery of Fe2+ and CO in
biological settings.