title: Characterization of a membrane calcium pathway induced by rotavirus infection in cultured cells.
abstract: Some viruses induce changes in membrane permeability during infection. We have shown previously that the porcine strain of rotavirus, OSU, induced an increase in the permeability to Na+, K+, and Ca2+ during replication in MA104 cells. In this work, we have characterized the divalent cation entry pathway by measuring intracellular Ca2+ in fura-2-loaded MA104 and HT29 cells in suspension. The permeability to Ca2+ and other cations was evaluated by the change of the intracellular concentration following an extracellular cation pulse. Rotavirus infection induced an increase in permeability to Ca2+, Ba2+, Sr2+, Mn2+, and Co2+. The rate of cation entry decreased over time as the intracellular concentration increased during the first 20 s. This indicates that regulatory mechanisms, including channel inactivation, are triggered. La3+ did not enter the cell and blocked the entry of the divalent cations in a dose-dependent manner. Metoxyverapamil (D600), a blocker of L-type voltage-gated channels, partially inhibited the entry of Ca2+ in virus-infected MA104 and HT29 cells. The results suggest that rotavirus infection of cultured cells activates a cation channel rather than nonspecific permeation through the plasma membrane. This activation involves the synthesis of viral proteins through mechanisms yet unknown. The increase in intracellular Ca2+ induced by the activation of this channel may be related to the increase in cytoplasmic and endoplasmic reticulum Ca2+ pools required for virus maturation and cell death.
authors.affiliation: Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas, Caracas 1020A, Venezuela.
authors.forename: J F
authors.initials: JF
authors.lastname: Pérez
authors.forename: M C
authors.initials: MC
authors.lastname: Ruiz
authors.forename: M E
authors.initials: ME
authors.lastname: Chemello
authors.forename: F
authors.initials: F
authors.lastname: Michelangeli
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D005711:Gallopamil / Q000494:pharmacology; D000882:Haplorhini; D007811:Lanthanum / Q000494:pharmacology; D008670:Metals / Q000378:metabolism; D012401:Rotavirus / Q000502:physiology*