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Variola and monkeypox viruses utilize conserved mechanisms of virion motility and release that depend on abl and SRC family tyrosine kinases.

ABSTRACT: Vaccinia virus (VacV) enters mammalian cells, replicates extranuclearly, and produces virions that move to the cell surface along microtubules, fuse with the plasma membrane, and move from infected cells toward apposing cells on actin-filled membranous protrusions or actin tails. To form actin tails, cell-associated enveloped virions (CEV) require Abl and Src family tyrosine kinases. Furthermore, release of CEV from the cell requires Abl but not Src family tyrosine kinases and is blocked by imatinib mesylate (STI-571; Gleevec), an Abl family kinase inhibitor used to treat chronic myelogenous leukemia in humans. Here we demonstrate that the Poxviridae family members monkeypox virus (MPX) and variola virus (VarV) use conserved mechanisms for actin motility and extracellular enveloped virion (EEV) release. Furthermore, we show that imatinib mesylate is effective in a mouse model of infection with VacV, whether delivered prophylactically or postinfection, and restricts spread of virions from the site of inoculation. While inhibitors of both Src and Abl family kinases, such as dasatinib (BMS-354825; Sprycel), are effective in limiting dissemination of VacV, VarV, and MPX in vitro, members of this class of drugs appear to have immunosuppressive effects in vivo that preclude their use as anti-infectives. Together, these data suggest a possible utility for imatinib mesylate in treating smallpox or MPX infections or complications associated with vaccination.

SUBMITTER: Reeves PM

PROVIDER: S-EPMC3014172 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature

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Variola and monkeypox viruses utilize conserved mechanisms of virion motility and release that depend on abl and SRC family tyrosine kinases.

Reeves Patrick M PM Smith Scott K SK Olson Victoria A VA Thorne Steve H SH Bornmann William W Damon Inger K IK Kalman Daniel D

Journal of virology 20101020 1

Vaccinia virus (VacV) enters mammalian cells, replicates extranuclearly, and produces virions that move to the cell surface along microtubules, fuse with the plasma membrane, and move from infected cells toward apposing cells on actin-filled membranous protrusions or actin tails. To form actin tails, cell-associated enveloped virions (CEV) require Abl and Src family tyrosine kinases. Furthermore, release of CEV from the cell requires Abl but not Src family tyrosine kinases and is blocked by imat ...[more]

PMID: 20962097

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Project description:Study questionCan of Clinical Genetics, Maastricht University Medical Centre, Maastricht kisspeptin and its analogues regulate the motility of human decidual stromal cells and what intracellular signaling pathways are involved?Summary answerKisspeptin analogue-mediated cell motility in human decidual stromal cells via the focal adhesion kinase (FAK)-steroid receptor coactivator (Src) pathway suggesting that kisspeptin may modulate embryo implantation and decidual programming in human pregnancy.What is known alreadyThe extravillous trophoblast invades the maternal decidua during embryo implantation and placentation. The motile behavior and invasive potential of decidual stromal cells regulate embryo implantation and programming of human pregnancy.Study design, size, durationHuman decidual stromal cells were isolated from healthy women undergoing elective termination of a normal pregnancy at 6- to 12-week gestation, after informed consent.Participants/materials, setting, methodsKisspeptin analogues were synthetic peptides. Cell motility was estimated by an invasion and migration assay. Immunoblot analysis was performed to investigate the expression of kisspeptin receptor and the effects of kisspeptin analogues on the phosphorylation of FAK and Src. Small interfering RNAs (siRNAs) were used to knock down the expression of kisspeptin receptor, FAK, Src, matrix metallo-proteinases (MMPs) 2 and 9, and extracellular signal-regulated protein kinase (ERK) 1/2.Main results and the role of chanceThe kisspeptin receptor was expressed in human decidual stromal cells. Kisspeptin agonist decreased, but antagonist increased, cell motility. Kisspeptin agonist decreased the phosphorylation of FAK and Src tyrosine kinases, whereas antagonist increased it. These effects on phosphorylation were abolished by kisspeptin receptor siRNA. The activation of cell motility by kisspeptin analogues was suppressed by siRNA knockdown of endogenous FAK (decreased 66%), Src (decreased 60%), kisspeptin receptor (decreased 26%), MMP-2 (decreased 36%), MMP-9 (decreased 23%), and ERK 1/2 inhibitor (decreased 27%).Limitations, reasons for cautionHuman decidual stromal cells were obtained from women having terminations after 6-12 weeks of pregnancy and differences in timing could affect their properties.Wider implications of the findingsKisspeptin acting within the endometrium has a potential modulatory role on embryo implantation and decidual programming of human pregnancy.Study funding/competing interest(s)This work was supported by grant NSC-104-2314-B-182A-146-MY2 (to H.-M.W.) from the Ministry of Science and Technology, Taiwan, and grants CMRPG3E0401 and CMRPG3E0402 (to H.-M.W.). This work was also supported by grants from the Canadian Institutes of Health Research to P.C.K.L. P.C.K.L. is the recipient of a Child & Family Research Institute Distinguished Investigator Award. The authors have no conflicts of interest to disclose.Trial registration numberN/A.

Project description:Gleevec, a well-known cancer therapeutic agent, is an effective inhibitor of several tyrosine kinases, including Abl and c-Kit, but displays less potency to inhibit closely homologous tyrosine kinases, such as Lck and c-Src. Because many structural features of the binding site are highly conserved in these homologous kinases, the molecular determinants responsible for the binding specificity of Gleevec remain poorly understood. To address this issue, free energy perturbation molecular dynamics (FEP/MD) simulations with explicit solvent was used to compute the binding affinity of Gleevec to Abl, c-Kit, Lck, and c-Src. The results of the FEP/MD calculations are in good agreement with experiments, enabling a detailed and quantitative dissection of the absolute binding free energy in terms of various thermodynamic contributions affecting the binding specificity of Gleevec to the kinases. Dominant binding free energy contributions arises from the van der Waals dispersive interaction, compensating about two-thirds of the unfavorable free energy penalty associated with the loss of translational, rotational, and conformational freedom of the ligand upon binding. In contrast, the contributions from electrostatic and repulsive interactions nearly cancel out due to solvent effects. Furthermore, the calculations show the importance of the conformation of the kinase activation loop. Among the kinases examined, Abl provides the most favorable binding environment for Gleevec via optimal protein-ligand interactions and a small free energy cost for loss of the translational, rotational, and conformational freedom upon ligand binding. The FEP/MD calculations additionally reveal that Lck and c-Src provide similar nonbinding interactions with the bound-Gleevec, but the former pays less entropic penalty for the ligand losing its translational, rotational, and conformational motions to bind, examining the empirically observed differential binding affinities of Gleevec between the two Src-family kinases.

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Variola and monkeypox viruses utilize conserved mechanisms of virion motility and release that depend on abl and SRC family tyrosine kinases.

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Variola and monkeypox viruses utilize conserved mechanisms of virion motility and release that depend on abl and SRC family tyrosine kinases.

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