Cytochalasin D enhances the accumulation of a protease‐resistant form of prion protein in ScN2a cells: involvement of PI3 kinase/Akt signalling pathway

Abstract

The conversion of a host-encoded PrPsen (protease-sensitive cellular prion protein) into a PrPres (protease-resistant pathogenic form) is a key process in the pathogenesis of prion diseases, but the intracellular mechanisms underlying PrPres amplification in prion-infected cells remain elusive. To assess the role of cytoskeletal proteins in the regulation of PrPres amplification, the effects of cytoskeletal disruptors on PrPres accumulation in ScN2a cells that were persistently infected with the scrapie Chandler strain have been examined. Actin microfilament disruption with cytochalasin D enhanced PrPres accumulation in ScN2a cells. In contrast, the microtubule-disrupting agents, colchicine, nocodazole and paclitaxel, had no effect on PrPres accumulation. In addition, a PI3K (phosphoinositide 3-kinase) inhibitor, wortmannin and an Akt kinase inhibitor prevented the cytochalasin D-induced enhancement of PrPres accumulation. Cytochalasin D-induced extension of neurite-like processes might correlate with enhanced accumulation of PrPres. The results suggest that the actin cytoskeleton and PI3K/Akt pathway are involved in the regulation of PrPres accumulation in prion-infected cells.

Extracellular ATP does not induce P2X7 receptor-dependent responses in cultured renal- and liver-derived swine macrophages

“…Immunocytochemical analyses were performed as described previously [10,11] . Primary antibodies against cytokeratin 18 (CK18; Millipore Co., Billerica, MA), cytokeratin 19 (CK19; Progen, Heidelberg, Germany), α-smooth muscle actin (SMA; Progen), macrophage scavenger receptor MSR-A:CD204 (KT022; TransGenic, Inc., Kumamoto, Japan), Iba 1 (Wako Pure Chemical Industries, Ltd, Osaka, Japan), and CD172a (VMRD, Inc., Pullman, WA) were used.…”