title: A host GPCR signaling network required for the cytolysis of infected cells facilitates release of apicomplexan parasites.
abstract: Following intracellular replication, the apicomplexan parasites Plasmodium falciparum and Toxoplasma gondii cause host cell cytolysis to facilitate parasite release and disease progression. Parasite exit from infected cells requires the interplay of parasite-derived proteins and host actin cytoskeletal changes; however, the host proteins underlying these changes remain obscure. We report the identification of a Gα(q)-coupled host-signaling cascade required for the egress of both P. falciparum and T. gondii. Gα(q)-coupled signaling results in protein kinase C (PKC)-mediated loss of the host cytoskeletal protein adducin and weakening of the cellular cytoskeleton. This cytoskeletal compromise induces catastrophic Ca(2+) influx mediated by the mechanosensitive cation channel TRPC6, which activates host calpain that proteolyzes the host cytoskeleton allowing parasite release. Reinforcing the feasibility of targeting host proteins as an antiparasitic strategy, mammalian PKC inhibitors demonstrated activity in murine models of malaria and toxoplasmosis. Importantly, an orally bioavailable PKC inhibitor prolonged survival in an experimental cerebral malaria model.
authors: Department of Pharmacology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors: Melanie G
authors: MG
authors: Millholland
authors: Satish
authors: S
authors: Mishra
authors: Christopher D
authors: CD
authors: Dupont
authors: Melissa S
authors: MS
authors: Love
authors: Bhumit
authors: B
authors: Patel
authors: Dustin
authors: D
authors: Shilling
authors: Marcelo G
authors: MG
authors: Kazanietz
authors: J Kevin
authors: JK
authors: Foskett
authors: Christopher A
authors: CA
authors: Hunter
authors: Photini
authors: P
authors: Sinnis
authors: Doron C
authors: DC
authors: Greenbaum
mesh_terms: D000818:Animals; D001329:Autolysis; D001343:Autophagy; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism; D006790:Host-Parasite Interactions; D006801:Humans; D016778:Malaria, Falciparum / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology / Q000503:physiopathology; D051379:Mice; D008810:Mice, Inbred C57BL; D010963:Plasmodium falciparum / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D014122:Toxoplasma / Q000502:physiology*; D014123:Toxoplasmosis / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology / Q000503:physiopathology
chemical_list: D043562:Receptors, G-Protein-Coupled; D002118:Calcium