Effect of Casein Kinase 1a Activator Pyrvinium Pamoate on Erythrocyte Ion Channels

Abstract

Pharmacological modification of protein kinase CK1 (casein kinase 1) has previously been shown to influence suicidal erythrocyte death or eryptosis, which is triggered by activation of Cl^--sensitive Ca²⁺-permeable cation channels. Ca²⁺ entering through those channels stimulates cell membrane scrambling and opens Ca²⁺-activated K⁺-channels resulting in KCl exit and thus cell shrinkage. The specific CK1-inhibitor D4476 (1 µM) blunted, whereas the specific CK1 αactivator pyrvinium pamoate (10 µM) enhanced cell membrane scrambling. The substances were at least partially effective through modification of cytosolic Ca²⁺-activity. The present study explored, whether pyrvinium pamoate indeed influences Cl^--sensitive cation-channels in erythrocytes. As a result, removal of Cl^-increased Fluo3-fluorescence (reflecting cytosolic Ca²⁺-activity), triggered cell membrane scrambling (apparent from annexin-V-binding), and decreased forward scatter (pointing to cell shrinkage). Pyrvinium pamoate significantly augmented the effect of Cl^--removal on Fluo3 fluorescence and annexin-V-binding, but blunted the effect on forward scatter. According to whole cell patch clamp recording, Cl^-removal activated a cation current, which was significantly enhanced by pyrvinium pamoate. Pyrvinium pamoate inhibited Ca²⁺-activated K⁺-channels. Ca²⁺-ionophore ionomycin (1 µM) decreased forward scatter, an effect significantly blunted by pyrvinium pamoate. In conclusion, pyrvinium pamoate activates Cl^--sensitive Ca²⁺-permeable cation channels with subsequent Ca²⁺-entry and inhibits Ca²⁺-activated K⁺-channels thus blunting the stimulating effect of Ca²⁺ on those channels, K⁺-exit and thus cell shrinkage.

Angiotensin II increases fibronectin and collagen I through the β-catenin-dependent signaling in mouse collecting duct cells

“…Cells were then treated with ANG II (10 Ϫ7 M) for 16 h. An additional group of cells was treated with either an inhibitor of the Wnt signaling pathway (pyrvinium pamoate; 10 Ϫ9 M) or an AT1 receptor (candesartan; 10 Ϫ7 M) blocker. The dose of pyrvinium pamoate was based on previous studies showing its effectiveness at nanomolar concentrations in reducing ␤ catenin phosphorylation and proliferation in tumor cells (22,28,38,45). Additionally, it has been shown that pyrivinium pamoate selectively potentiates the casein kinase alpha activity with an EC 50 of 10 nM (45).…”

Stimulation of Erythrocyte Cell Membrane Scrambling by Gedunin

“…Increased [Ca 2+ ] i further triggers phospholipid scrambling of the cell membrane with translocation of phosphatidylserine to the erythrocyte surface [15]. Signaling in the regulation of eryptosis includes in addition ceramide formation [15], caspase activation [17,18,19,20,21] and deranged regulation of several kinases such as AMP activated kinase AMPK [22], casein kinase 1α [23,24], cGMP-dependent protein kinase [25], Janus-activated kinase JAK3 [26], protein kinase C [27], p38 kinase [28], PAK2 kinase [29] as well as sorafenib [30] and sunitinib [31] sensitive kinases.…”

Stimulation of Eryptosis by Cryptotanshinone

“…Increased [Ca 2+ ] i triggers in addition phospholipid scrambling of the cell membrane with phosphatidylserine exposure at the erythrocyte surface [24]. Further triggers of eryptosis include ceramide formation [26], caspase activation [27,28,29,30,31] and deranged activities of AMP activated kinase AMPK [32], casein kinase 1α [33,34], cGMP-dependent protein kinase [35], Janus-activated kinase JAK3 [36], protein kinase C [37], p38 kinase [38], PAK2 kinase [39] sorafenib sensitive kinases [40] as well as sunitinib sensitive kinases [41]. …”