Bunyavirus SFTSV exploits autophagic flux for viral assembly and egress.
Ontology highlight
ABSTRACT:
SUBMITTER: Yan JM
PROVIDER: S-EPMC9298452 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The coronavirus transforms the cytoplasm of susceptible cells to support virus replication. It also activates autophagy-like processes, the role of which is not well understood. Here, we studied SARS-CoV-2-infected Vero E6 cells using transmission electron microscopy and autophagy PCR array. After 6-24 h post-infection (hpi), the cytoplasm of infected cells only contained double-membrane vesicles, phagophores, and phagosomes engulfing virus particles and cytoplasmic debris, including damaged mitochondria. The phagosomes interacted with the viral nucleoprotein complex, virus particles, mitochondria, and lipid droplets. The phagosomes transformed into egress vacuoles, which broke through the plasmalemma and discharged the virus particles. The Vero E6 cells exhibited pronounced virus replication at 6 hpi, which stabilized at 18-24 hpi at a high level. The autophagy PCR array tests revealed a significant upregulation of 10 and downregulation of 8 autophagic gene markers out of 84. Altogether, these results underline the importance of autophagy-like processes for SARS-CoV-2 maturation and egress, and point to deviations from a canonical autophagy response.
| S-EPMC9781122 | biostudies-literature
Project description:Herpes simplex virus (HSV-1) progeny form in the nucleus and exit to successfully infect other cells. Newly formed capsids navigate complex chromatin architecture to reach the inner nuclear membrane (INM) and egress. Here, we demonstrate by transmission electron microscopy (TEM) that HSV-1 capsids traverse heterochromatin associated with trimethylation on histone H3 lysine 27 (H3K27me3) and the histone variant macroH2A1. Through chromatin profiling during infection, we revealed global redistribution of these marks whereby massive host genomic regions bound by macroH2A1 and H3K27me3 correlate with decreased host transcription in active compartments. We found that the loss of these markers resulted in significantly lower viral titers but did not impact viral genome or protein accumulation. Strikingly, we discovered that loss of macroH2A1 or H3K27me3 resulted in nuclear trapping of capsids. Finally, by live-capsid tracking, we quantified this decreased capsid movement. Thus, our work demonstrates that HSV-1 takes advantage of the dynamic nature of host heterochromatin formation during infection for efficient nuclear egress.
| S-EPMC10373338 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2023-07-01 | GSE209820 | GEO
Project description:Miz1 is a zinc finger protein that regulates expression of cell cycle inhibitors as part of a complex with Myc. Cell cycle-independent functions of Miz1 are poorly understood. Here, we use a Nestin-Cre transgene to delete an essential domain of Miz1 in the central nervous system (Miz1M-NM-^TPOZNes). Miz1M-NM-^TPOZNes mice display cerebellar neurodegeneration characterized by the progressive loss of Purkinje cells. Chromatin immunoprecipitation sequencing and biochemical analyses show that Miz1 activates transcription upon binding to a non-palindromic sequence present in core promoters. Target genes of Miz1 encode regulators of autophagy and proteins involved in vesicular transport that are required for autophagy. Miz1M-NM-^TPOZ neuronal progenitors and fibroblasts show reduced autophagic flux. Consistently, polyubiquitinated proteins and p62/Sqtm1 accumulate in the cerebella of Miz1M-NM-^TPOZNes mice, characteristic features of defective autophagy. Our data suggest that Miz1 may link cell growth and ribosome biogenesis to the transcriptional regulation of vesicular transport and autophagy. ChIP-Seq with H190 and G18 on an Illumina Genome Analyzer IIx.
2013-09-27 | E-GEOD-48602 | biostudies-arrayexpress
Project description:Herpes simplex virus replicates and forms progeny in the nucleus where it must overcome host chromatin to establish a successful infection. During lytic infection, newly formed viral capsids navigate through heterochromatin channels at the nuclear periphery to egress out of the nucleus. In uninfected cells, specific histone marks such as trimethylation on histone H3 lysine 27 (H3K27me3) and the histone variant macroH2A1 delineate heterochromatin regions, or repressed chromatin, that are predominantly located in the nuclear periphery. We examined these markers during HSV-1 lytic infection in primary cells and discovered a striking increase in the levels of macroH2A1 and H3K27me3. Here, we demonstrate that the loss of macroH2A1 results in significantly lower viral titers but does not impair viral transcription, protein production, or replication. By inhibiting the deposition of H3K27me3 by EZH2, we further show that reduction of H3K27me3 also leads to a significant decrease in viral titers. Through chromatin profiling via Cleavage Under Targets and tagmentation (CUT&Tag) of macroH2A1 and H3K27me3, we define the specific chromatin regions that change dynamically during HSV-1 lytic infection and show that regions with increased macroH2A1 and H3K27me3 correlate with decreased host transcription as measured by RNA-seq. Furthermore, we find by electron microscopy that loss of macroH2A1 results in reduced heterochromatin at the nuclear periphery and significantly more viral capsids trapped in the nuclear compartment. Using both high and low shedding clinical isolates of HSV-1, we similarly find that HSV-1 titers are significantly reduced in the absence of macroH2A1. Our work demonstrates that HSV-1 takes advantage of the dynamic nature of host heterochromatin formation during infection for efficient viral egress from the nuclear compartment.
2023-07-01 | GSE209632 | GEO
Project description:Herpes simplex virus replicates and forms progeny in the nucleus where it must overcome host chromatin to establish a successful infection. During lytic infection, newly formed viral capsids navigate through heterochromatin channels at the nuclear periphery to egress out of the nucleus. In uninfected cells, specific histone marks such as trimethylation on histone H3 lysine 27 (H3K27me3) and the histone variant macroH2A1 delineate heterochromatin regions, or repressed chromatin, that are predominantly located in the nuclear periphery. We examined these markers during HSV-1 lytic infection in primary cells and discovered a striking increase in the levels of macroH2A1 and H3K27me3. Here, we demonstrate that the loss of macroH2A1 results in significantly lower viral titers but does not impair viral transcription, protein production, or replication. By inhibiting the deposition of H3K27me3 by EZH2, we further show that reduction of H3K27me3 also leads to a significant decrease in viral titers. Through chromatin profiling via Cleavage Under Targets and tagmentation (CUT&Tag) of macroH2A1 and H3K27me3, we define the specific chromatin regions that change dynamically during HSV-1 lytic infection and show that regions with increased macroH2A1 and H3K27me3 correlate with decreased host transcription as measured by RNA-seq. Furthermore, we find by electron microscopy that loss of macroH2A1 results in reduced heterochromatin at the nuclear periphery and significantly more viral capsids trapped in the nuclear compartment. Using both high and low shedding clinical isolates of HSV-1, we similarly find that HSV-1 titers are significantly reduced in the absence of macroH2A1. Our work demonstrates that HSV-1 takes advantage of the dynamic nature of host heterochromatin formation during infection for efficient viral egress from the nuclear compartment.
2023-07-01 | GSE208127 | GEO
Project description:Miz1 is a zinc finger protein that regulates expression of cell cycle inhibitors as part of a complex with Myc. Cell cycle-independent functions of Miz1 are poorly understood. Here, we use a Nestin-Cre transgene to delete an essential domain of Miz1 in the central nervous system (Miz1ΔPOZNes). Miz1ΔPOZNes mice display cerebellar neurodegeneration characterized by the progressive loss of Purkinje cells. Chromatin immunoprecipitation sequencing and biochemical analyses show that Miz1 activates transcription upon binding to a non-palindromic sequence present in core promoters. Target genes of Miz1 encode regulators of autophagy and proteins involved in vesicular transport that are required for autophagy. Miz1ΔPOZ neuronal progenitors and fibroblasts show reduced autophagic flux. Consistently, polyubiquitinated proteins and p62/Sqtm1 accumulate in the cerebella of Miz1ΔPOZNes mice, characteristic features of defective autophagy. Our data suggest that Miz1 may link cell growth and ribosome biogenesis to the transcriptional regulation of vesicular transport and autophagy.
2013-09-27 | GSE48602 | GEO
Project description:Inside cells, viruses build specialized compartments for replication and morphogenesis. We observed that virus release associates with specific structures found on the surface of mammalian cells. Cultured adherent cells were infected with a bunyavirus and processed for oriented sectioning and transmission electron microscopy. Imaging of cell basal regions showed sophisticated multilamellar structures (MLS) and extracellular filament bundles with attached viruses. Correlative light and electron microscopy confirmed that both MLS and filaments proliferated during the maximum egress of new viruses. MLS dimensions and structure were reminiscent of those reported for the nanostructures on gecko fingertips, which are responsible for the extraordinary attachment capacity of these lizards. As infected cells with MLS were more resistant to detachment than control cells, we propose an adhesive function for these structures, which would compensate for the loss of adherence during release of new virus progeny.
| S-EPMC3683019 | biostudies-literature
Project description:Doxorubicin (DOX) cardiotoxicity is an important factor of heart failure. The only clinically approved drug is dexrazoxane, while its side effect of secondary malignancies severely limited its application. It is urgent to find other alternative efficacious molecular for these chemotherapy patients. Colchicine is a safe and well tolerated anti-inflammation drug which also functions in attenuating the reactive oxygen species (ROS) generation. High dose of colchicine was reported block the autophagosome-lysosome fusion in cancer cells due to its destabilization effect to the microtubule system, while how colchicine affects the autophagic flux in cardiomyocytes is largely unknown. Recent years low dose of colchicine administration was reported helpful to the patients with pericarditis, postprocedural atrial fibrillation and coronary artery disease, most of the research attributed it to its anti-inflammation effect. Whether the autophagic flux regulated by colchicine also benefits to DOX induced heart failure remains unclear. Doxorubicin (DOX) administration was used to establish heart failure models in vivo and in vitro. Results showed that DOX blocked the autophagic vacuoles degradation, leading to damaged mitochondria and ROS accumulation. Heart failure characteristics were obviously improved after low dose of colchicine administration. Mechanistically, low dose of colchicine promoted the autolysosome degradation, cleared the damaged mitochondria, and ROS accumulation induced by the DOX and as a result attenuated DOX cardiotoxicity.
2024-06-20 | GSE247345 | GEO
Project description:The stimulation of autophagy or lysosomes has been considered therapeutic for neurodegenerative disorders because the accumulation of misfolded proteins is commonly observed in the brains of individuals with these diseases. Although zinc is known to play critical roles in the functions of lysosomes and autophagy, the mechanism behind this regulatory relationship remains unclear. Therefore, in this study, we examined which mechanism is involved in zinc-mediated activation of autophagy and lysosome. Exposure to zinc at a sub-lethal concentration activated autophagy in a concentration-dependent manner in mRFP-GFP-LC3-expressing H4 glioma cells. Zinc also rescued the blocking of autophagic flux arrested by pharmaceutical de-acidification. Co-treatment with zinc attenuated the chloroquine (CQ)-induced increase in the number and size of mRFP-GFP-LC3 puncta in H4 cells and accumulation of p62 by CQ or ammonium chloride in both H4 and mouse cerebrocortical cultures. Zinc rapidly induced the expression of cathepsin B (CTSB) and cathepsin D (CTSD), representative lysosomal proteases in neurons, which appeared likely to be mediated by transcription factor EB (TFEB). We observed the translocation of TFEB from neurite to nucleus and the dephosphorylation of TFEB by zinc. The addition of cycloheximide, a chemical inhibitor of protein synthesis, inhibited the activity of CTSB and CTSD at 8 h after zinc exposure but not at 1 h, indicating that only late lysosomal activation was dependent on the synthesis of CTSB and CTSD proteins. At the very early time point, the activation of cathepsins was mediated by an increased assembly of V-ATPase on lysosomes and resultant lysosomal acidification. Finally, considering that P301L mutation in tau protein causes frontotemporal dementia through aggressive tau accumulation, we investigated whether zinc reduces the accumulation of protein aggregates in SK-N-BE(2)-C neuroblastoma cells expressing wild-type tau or mutant P301L-tau. Zinc markedly attenuated the levels of phosphorylated tau and total tau as well as p62 in both wild-type and mutant tau-overexpressing cells. We also observed that zinc was more effective than rapamycin at inducing TFEB-dependent CTSB and CTSD expression and V-ATPase-dependent lysosomal acidification and CTSB/CTSD activation. These results suggest that the regulation of zinc homeostasis could be a new approach for developing treatments for neurodegenerative diseases, including Alzheimer's and Parkinson's.
| S-EPMC9558701 | biostudies-literature