Project description:Human cytomegalovirus infects multiple cell types, including fi-; broblasts and epithelial cells. It penetrates fibroblasts by fusion at; the cell surface but is endocytosed into epithelial cells. In this; report, we demonstrate by electron microscopy that the virus uses; two different routes to enter retinal pigmented epithelial cells,; depending on the cell type in which the infecting virus was; produced. Virus produced in epithelial cells preferentially fuses; with the plasma membrane, whereas fibroblast-derived virus; mostly enters by receptor-mediated endocytosis. Treatment of; epithelial cells with agents that block endosome acidification; inhibited infection by virus produced in fibroblasts but had only a; modest effect on infection by virus from epithelial cells. Epithelial; cell-generated virions had higher intrinsic ââfusion-from-withoutââ; activity than fibroblast-generated particles, and the two virus; preparations triggered different cellular signaling responses, as; evidenced by markedly different transcriptional profiles. We propose; that the cell type in which a human cytomegalovirus particle; is produced likely influences its subsequent spread and its contribution; to pathogenesis. Experiment Overall Design: A single strain of Human Cytomegalovirus (HCMV), termed BADrUL131, was used to prepare viral stocks from either fibroblast cells or from endothelial cells. These viral preparations (fibroBADrUL131 and epiBADrUL131) were used to infect ARP-19 cells (Human retinal pigmented epithelial cells) for either 6 hours or 10 hours. Total RNA was collected, labeled and used to hybridize to Agilent whole genome oligo microarrays and were normalized to a control reference RNA pool.
Project description:Human cytomegalovirus infects multiple cell types, including fi- broblasts and epithelial cells. It penetrates fibroblasts by fusion at the cell surface but is endocytosed into epithelial cells. In this report, we demonstrate by electron microscopy that the virus uses two different routes to enter retinal pigmented epithelial cells, depending on the cell type in which the infecting virus was produced. Virus produced in epithelial cells preferentially fuses with the plasma membrane, whereas fibroblast-derived virus mostly enters by receptor-mediated endocytosis. Treatment of epithelial cells with agents that block endosome acidification inhibited infection by virus produced in fibroblasts but had only a modest effect on infection by virus from epithelial cells. Epithelial cell-generated virions had higher intrinsic ‘‘fusion-from-without’’ activity than fibroblast-generated particles, and the two virus preparations triggered different cellular signaling responses, as evidenced by markedly different transcriptional profiles. We propose that the cell type in which a human cytomegalovirus particle is produced likely influences its subsequent spread and its contribution to pathogenesis. Keywords: cell type comparison, viral infection, cell tropism, viral entry
Project description:Placental infection plays a central role in the pathogenesis of congenital human cytomegalovirus (HCMV) infections and is a cause of fetal growth restriction and pregnancy loss. HCMV can replicate in some trophoblast cell types, but it remains unclear how the virus evades antiviral immunity in the placenta and how infection compromises placental development and function. Human trophoblast stem cells (TSCs) can be differentiated into extravillous trophoblasts (EVTs) and syncytiotrophoblasts (STBs). This study assessed the utility of TSCs as a model of HCMV infection in the first trimester placenta. TSCs and TSC-derived EVTs and STBs were infected with HCMV (TB40/Ewt-mCherry). RNA was isolated from infected cells at 24, 48, and 72 hours post-infection and Illumina RNA-Sequencing was used to measure viral and host gene expression. Viral gene expression in TSCs does not follow the kinetic patterns observed during lytic infection in fibroblasts. Canonical antiviral responses were largely not observed in HCMV-infected TSCs and TSC-derived trophoblasts. Rather, infection dysregulated factors involved in cell identity, differentiation, and WNT signaling.
Project description:We introduce target sites for the microRNA (miRNA) miR-142 into the 3’-untranslated region of the human cytomegalovirus (HCMV) IE2 to study the transcriptional effect of IE2 knock-down on both viral and host genes in cells that express miR-142. When comparing transcriptional data from miR-142 expressing macrophages infected with HCMV to macrophages infected with IE2-miR-142 targeted HCMV, we see a knock-down of IE2 and differential regulation of predicted viral targets of IE2 including IE1, vIL-10 and US29. We then generated fibroblasts expressing miR-142 to study the knock-down of IE2 in a different cellular system and find drastic differences in loss of IE2 on the host transcriptional profile in the two different cell types.
Project description:Data-independent acquisition assessment of human fibroblasts and epithelial cells infected with different strains of human cytomegalovirus (HCMV). Viruses are ubiquitous entities that infect organisms across the kingdoms of life. While viruses can infect a range of cells, tissues, and organisms, this aspect is often not explored in cell culture analyses. There is limited information about which infection-induced changes are shared or distinct in different cellular environments. The prevalent pathogen HCMV remodels the structure and function of subcellular organelles and their interconnected networks formed by membrane contact sites (MCSs). A large portion of this knowledge has been derived from fibroblasts infected with a lab-adapted HCMV strain. Here, we assess strain- and cell type-specific alterations in MCSs and organelle remodeling induced by HCMV. Integrating quantitative mass spectrometry, super-resolution microscopy, and molecular virology assays, we compare infections with lab-adapted and low-passage HCMV strains in fibroblast and epithelial cells. We determine that, despite baseline proteome disparities between uninfected fibroblast and epithelial cells, infection induces convergent changes and is remarkably similar. We show that hallmarks of HCMV infection in fibroblasts, mitochondria-ER encapsulations (MENCs) and peroxisome proliferation, are also conserved in infected epithelial and macrophage-like cells. Exploring cell type-specific differences, we demonstrate that fibroblasts rely on endosomal cholesterol transport while epithelial cells rely on cholesterol from the Golgi. Despite these mechanistic differences, infections in both cell types result in phenotypically similar cholesterol accumulation at the viral assembly complex. Our findings highlight the adaptability of HCMV, in that infections can be tailored to the initial cell state by inducing both shared and unique proteome alterations, ultimately promoting a unified pro-viral environment.
Project description:Mariana Esther Martinez-Sanchez, Luis Mendoza, Carlos Villarreal & Elena R. Alvarez-Buylla. A Minimal Regulatory Network of Extrinsic and Intrinsic Factors Recovers Observed Patterns of CD4+ T Cell Differentiation and Plasticity. PLOS Computational Biology 11, 6 (2015).
CD4+ T cells orchestrate the adaptive immune response in vertebrates. While both experimental and modeling work has been conducted to understand the molecular genetic mechanisms involved in CD4+ T cell responses and fate attainment, the dynamic role of intrinsic (produced by CD4+ T lymphocytes) versus extrinsic (produced by other cells) components remains unclear, and the mechanistic and dynamic understanding of the plastic responses of these cells remains incomplete. In this work, we studied a regulatory network for the core transcription factors involved in CD4+ T cell-fate attainment. We first show that this core is not sufficient to recover common CD4+ T phenotypes. We thus postulate a minimal Boolean regulatory network model derived from a larger and more comprehensive network that is based on experimental data. The minimal network integrates transcriptional regulation, signaling pathways and the micro-environment. This network model recovers reported configurations of most of the characterized cell types (Th0, Th1, Th2, Th17, Tfh, Th9, iTreg, and Foxp3-independent T regulatory cells). This transcriptional-signaling regulatory network is robust and recovers mutant configurations that have been reported experimentally. Additionally, this model recovers many of the plasticity patterns documented for different T CD4+ cell types, as summarized in a cell-fate map. We tested the effects of various micro-environments and transient perturbations on such transitions among CD4+ T cell types. Interestingly, most cell-fate transitions were induced by transient activations, with the opposite behavior associated with transient inhibitions. Finally, we used a novel methodology was used to establish that T-bet, TGF-β and suppressors of cytokine signaling proteins are keys to recovering observed CD4+ T cell plastic responses. In conclusion, the observed CD4+ T cell-types and transition patterns emerge from the feedback between the intrinsic or intracellular regulatory core and the micro-environment. We discuss the broader use of this approach for other plastic systems and possible therapeutic interventions.
Project description:Human cytomegalovirus induces a pro-inflammatory monocyte following infection. To begin to address how HCMV induces these rapid changes in infected monocytes, we examined the transcriptome of infected monocytes. Global transcriptional profiling using cDNA microarrays revealed a significant number of pro-inflammatory genes were upregulated within 4 hours post infection. Experiment Overall Design: To begin to globally define the HCMV-induced changes in monocyte function, we performed a transcriptome analysis. Specifically, a cDNA microarray containing 12,626 unique probe sets was utilized to assess the modulation of the monocyte transcriptome at 4 hours post infection. A total of 6 replicates from mock-infected and 6 replicates from HCMV-infected monocytes were analyzed in this study.
Project description:Human cytomegalovirus (hCMV) primo-infection, reinfection and/or reactivation is a major issue during pregnancy and affects 1% of live births in western countries, making hCMV the most frequently transmitted virus in utero. Despite the extensive research conducted so far, the pathophysiology of this congenital infection remains unclear. Recently, increasing evidence point out the role of small extracellular vesicles (sEVs) in cell-cell communication underlying the feto-placenta-maternal dialogue during pregnancy. In this study, we examined the impact of hCMV infection on the protein composition and function of placental sEVs. We observed that infection of placental cells led to an alteration of protein composition of their secreted sEVs, suggesting that placental sEVs may acquire a proviral phenotype. Functional studies performed on fetal recipient cells, notably neural stem cells, confirmed the ability of sEVs produced by infected cells to facilitate further infection of naive recipient cells. Altogether, our study demonstrates that placental sEVs are key players of hCMV pathophysiology during congenital infection, and may favor the transmission of the virus towards the fetus.
Project description:Martinez-Sanchez2015 - T CD4+ lymphocyte
transcriptional-signaling regulatory network
This model is described in the article:
A Minimal Regulatory Network
of Extrinsic and Intrinsic Factors Recovers Observed Patterns
of CD4+ T Cell Differentiation and Plasticity.
Martinez-Sanchez ME, Mendoza L,
Villarreal C, Alvarez-Buylla ER.
PLoS Comput. Biol. 2015 Jun; 11(6):
e1004324
Abstract:
CD4+ T cells orchestrate the adaptive immune response in
vertebrates. While both experimental and modeling work has been
conducted to understand the molecular genetic mechanisms
involved in CD4+ T cell responses and fate attainment, the
dynamic role of intrinsic (produced by CD4+ T lymphocytes)
versus extrinsic (produced by other cells) components remains
unclear, and the mechanistic and dynamic understanding of the
plastic responses of these cells remains incomplete. In this
work, we studied a regulatory network for the core
transcription factors involved in CD4+ T cell-fate attainment.
We first show that this core is not sufficient to recover
common CD4+ T phenotypes. We thus postulate a minimal Boolean
regulatory network model derived from a larger and more
comprehensive network that is based on experimental data. The
minimal network integrates transcriptional regulation,
signaling pathways and the micro-environment. This network
model recovers reported configurations of most of the
characterized cell types (Th0, Th1, Th2, Th17, Tfh, Th9, iTreg,
and Foxp3-independent T regulatory cells). This
transcriptional-signaling regulatory network is robust and
recovers mutant configurations that have been reported
experimentally. Additionally, this model recovers many of the
plasticity patterns documented for different T CD4+ cell types,
as summarized in a cell-fate map. We tested the effects of
various micro-environments and transient perturbations on such
transitions among CD4+ T cell types. Interestingly, most
cell-fate transitions were induced by transient activations,
with the opposite behavior associated with transient
inhibitions. Finally, we used a novel methodology was used to
establish that T-bet, TGF-? and suppressors of cytokine
signaling proteins are keys to recovering observed CD4+ T cell
plastic responses. In conclusion, the observed CD4+ T
cell-types and transition patterns emerge from the feedback
between the intrinsic or intracellular regulatory core and the
micro-environment. We discuss the broader use of this approach
for other plastic systems and possible therapeutic
interventions.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000593.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:CD8+ T cells play a critical role in the immune response to viral pathogens. Persistent human CMV (HCMV) infection results in a strong increase in the number of virus-specific, quiescent effector-type CD8+ T cells with constitutive cytolytic activity, but the molecular pathways involved in the induction and maintenance of these cells are unknown. We show here that HCMV infection induced acute and lasting changes in the transcriptomes of virus-reactive T cells collected from HCMV-seropositive patients at distinct stages of infection. Enhanced cell cycle and metabolic activity was restricted to the acute phase of the response, but at all stages, HCMV-specific CD8+ T cells expressed the Th1-associated transcription factors T-bet (TBX21) and eomesodermin (EOMES), in parallel with continuous expression of IFNG mRNA and IFN-g–regulated genes. The cytolytic proteins granzyme B and perforin as well as the fractalkine-binding chemokine receptor CX3CR1 were found in virus-reactive cells throughout the response. During HCMV latency, virus-specific CD8+ T cells lacked the typical features of exhausted cells found in other chronic infections. Persistent effector cell traits together with the permanent changes in chemokine receptor usage of virus-specific, nonexhausted, long-lived CD8+ T cells may be crucial to maintain lifelong protection from HCMV reactivation. CD8+ T cells of naive, effector, and memory type were isolated from six latently chronic-infected healthy donors. For RNA isolation and microarray analysis, 3 independent donors and a pool of 3 additional healthy individuals were used. Total RNA of all naive CD8+ T cells was pooled and used as a common reference sample.