Background
Senicapoc is an inhibitor of intermediate conductance calcium-activated potassium (IKCa1/KCa3.1) channels.1,2 It inhibits rubidium efflux from and dehydration of isolated human red blood cells (RBCs) induced by the calcium ionophore A23187 .1 Senicapoc (10 mg/kg twice per day) reduces IKCa1/KCa3.1 channel activity, increases potassium levels in RBCs, and decreases erythrocyte density in the SAD transgenic mouse model of sickle cell disease. It inhibits IL-2, IFN-γ, IL-12, and IL-17A production in CD3+ T cells stimulated with phorbol 12-myristate 13-acetate and ionomycin when used at a concentration of 1 μM.3 Senicapoc (100 mg/kg) increases the paw withdrawal threshold in a rat model of chronic constriction injury (CCI) of the sciatic nerve.2
1.Stocker, J.W., De Franceschi, L., McNaughton-Smith, G.A., et al.ICA-17043, a novel gardos channel blocker, prevents sickled red blood cell dehydration in vitro and in vivo in SAD miceBlood101(6)2412-2418(2003)
2.Staal, R.G.W., Khayrullina, T., Zhang, H., et al.Inhibition of the potassium channel KCa 3.1 by senicapoc reverses tactile allodynia in rats with peripheral nerve injuryEur. J. Pharmacol.7951-7(2017)
3.Hansen, L.K., Sevelsted-M?ller, L., Rabjerg, M., et al.Expression of T-cell KV1.3 potassium channel correlates with pro-inflammatory cytokines and disease activity in ulcerative colitisJ. Crohns Colitis8(11)1378-1391(2014)
Protocol
Cell experiment: | The whole blood is initially diluted 1:1 with Modified Flux Buffer (MFB), consisting of 140 mM NaCl, 5 mM KCl, 10 mM Tris (tris(hydroxymethyl)aminomethane), 0.1 mM EGTA (ethyleneglycoltetraacetic acid) (pH=7.4). The blood is centrifuged at 1000 rpm, and the pellet comprised primarily of RBCs is washed 3 times with MFB. The cells are then loaded with?86Rb+?by incubating the washed cells with 86Rb+?at a final concentration of 0.185 MBq/mL (5 μCi/mL) in MFB for at least 3 hours at 37°C. After loading with 86Rb+, the RBCs are washed 3 times with chilled MFB. The cells are then incubated for 10 minutes with test compound (senicapoc) at concentrations that ranged from 1 nM to 10 000 nM. Efflux of?86Rb+?is initiated by raising intracellular calcium levels in the RBCs with the addition of CaCl2?and A23187 (a calcium ionophore) to final concentrations of 2 mM and 5 μM, respectively. After 10 minutes of incubation at room temperature, the RBCs are pelleted in a microcentrifuge, and the supernatant is removed and counted in a Wallac MicroBeta liquid scintillation counter.? |
Animal experiment: | Transgenic Hbbsingle/single?SAD1 (SAD) female and male mice?between 3 and 6 months of age, weighing 25 to 30 g, are used for this study. The SAD mice are divided into 2 groups, and either vehicle (n=6) or senicapoc (10 mg/kg) (n=6) is administered orally by gavage twice daily. C57B6/2J mice are used as controls (wild-type mice). Hematologic parameters are evaluated at baseline and after 11 and 21 days of therapy. Blood sampling and vehicle administration have previously been shown not to affect the blood parameters measured in this study. |
参考文献: [1]. Stocker JW, et al. ICA-17043, a novel Gardos channel blocker, prevents sickled red blood cell dehydration in vitro and in vivo in SAD mice. Blood. 2003 Mar 15;101(6):2412-8.
[2]. Van Der Velden J, et al. K(Ca)3.1 channel-blockade attenuates airway pathophysiology in a sheep model of chronic asthma. PLoS One. 2013 Jun 24;8(6):e66886.
[3]. Staal RG, et al. Inhibition of the potassium channel KCa3.1 by senicapoc reverses tactile allodynia in rats with peripheral nerve injury. Eur J Pharmacol. 2017 Jan 15;795:1-7. |
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