Search

The intermediate-conductance Ca(2+)-activated K(+) channel KCa3.1 (also known as KCNN4, IK1, or the Gárdos channel) plays an important role in the activation of T and B cells, mast cells, macrophages, and microglia by regulating membrane potential, cellular volume, and calcium signaling. KCa3.1 is further involved in the proliferation of dedifferentiated vascular smooth muscle cells and fibroblast and endothelium-derived hyperpolarization responses in the vascular endothelium. Accordingly, KCa3.1 inhibitors are therapeutically interesting as immunosuppressants and for the treatment of a wide range of fibroproliferative disorders, whereas KCa3.1 activators constitute a potential new class of endothelial function preserving antihypertensives. Here, we report the development of QPatch assays for both KCa3.1 inhibitors and activators. During assay optimization, the Ca(2+) sensitivity of KCa3.1 was studied using varying intracellular Ca(2+) concentrations. A free Ca(2+) concentration of 1 μM was chosen to optimally test inhibitors. To identify activators, which generally act as positive gating modulators, a lower Ca(2+) concentration (∼200 nM) was used. The QPatch results were benchmarked against manual patch-clamp electrophysiology by determining the potency of several commonly used KCa3.1 inhibitors (TRAM-34, NS6180, ChTX) and activators (EBIO, riluzole, SKA-31). Collectively, our results demonstrate that the QPatch provides a comparable but much faster approach to study compound interactions with KCa3.1 channels in a robust and reliable assay.

Lutein, the primary carotenoid present in the central area of the retina of eye appears to be associated with the protection against age-related macular degeneration (the leading cause of blindness in older adults). Its lipophilicity and consequently its scarce water solubility (1.3×10(-9)M) represent a drawback for bioavailability. To circumvent these unfavorable characteristics, in this work lutein (Lut) have been encapsulated in amphiphilic cyclodextrin (ACyD) by following the well-established strategy of entrapping a lipophilic drug in CyD carriers. Primary face butyrate modified β-cyclodextrins (C(4:7)) form in water nanoaggregates with a average size of 250nm and a ζ-potential of about -6mV. They are able to entrap lutein at 1:6 Lut/ACyD molar ratio by yielding nanoassemblies of vesicular aspect (320nm and -8mV) such as observed by static, dynamic and electrophoretic light-scattering. UV-vis measurements revealed that electronic properties of lutein were maintained when interact with ACyD nanoaggregates. The monitoring of the entapped carotenoid leaking from ACyD nanostructures was investigated suggesting the potential of Lut/ACyD nanoassemblies in drug delivery., (Published by Elsevier B.V.)