Project description:SARS-CoV-2 pandemic has caused a dramatic health, social and economic crisis worldwide. To better understand the host-virus interactions and identify potentially targetable host factors, we have conducted CRISPR-Cas9 genetic screens using SARS-CoV-2 pseudotyped lentiviruses on human lung cancer cells. Our results recapitulate many findings from previous screens that used full SARS-CoV-2 viruses, but also unveil two novel critical host factors: SPNS1 and PLAC8. Functional experiments with full SARS-CoV-2 viruses have confirmed that loss-of-function of these genes impairs viral entry. Importantly, we have found that PLAC8 is a key limiting host factor whose overexpression boosts viral infection in eight different human lung cancer cell lines. Using single-cell RNA-Seq data analyses, we demonstrate that PLAC8 is highly expressed in ciliated and secretory cells from the respiratory tract and in gut enterocytes, cell types that are highly susceptible to SARS-CoV-2 infection. Finally, proteomics and cell biology studies suggest that SPNS1 and PLAC8 affect viral entry through regulation of autophagy and lysosomal function.
Project description:The marine diatom Guinardia delicatula is a cosmopolitan species that dominates seasonal blooms in the English Channel and the North Sea. Several eukaryotic parasites are known to induce the mortality of this key-stone species. Here, we report the isolation and the characterization of the first viruses that infect G. delicatula. Viruses were isolated from the Western English Channel (SOMLIT-ASTAN station) during the late summer bloom decline of G. delicatula. A combination of laboratory approaches revealed that these lytic viruses (GdelRNAV) are small untailed particles of 35-38 nm in diameter that replicated in the host cytoplasm where both unordered particles and crystalline arrays were formed. GdelRNAV displayed a linear single-stranded RNA genome of ~9 kb, including two open reading frames encoding for replication and structural polyproteins. Phylogenetic relationships based on the RNA-dependent-RNA-polymerase gene marker showed that GdelRNAV were new members of the Bacillarnavirus, a monophyletic genus belonging to the order Picornavirales. GdelRNAV were specific to several strains of G. delicatula, they were produced rapidly (< 12h) and in numbers (9.34 x 104 virions per host cell). We recorded a substantial delay (72 h) between virions release and host cell lysis. Our analysis points to variable viral susceptibilities of the host during the early exponential growth phase. Interestingly, we consistently failed to isolate viruses during spring and early summer while G. delicatula developed rapid and massive blooms. While our study suggests that viruses do contribute to the decline of G. delicatula late summer bloom, they may not be the primary mortality agents during the remaining blooms at SOMLIT-ASTAN. Future studies should focus on the relative contribution of the viral and eukaryotic pathogens to the control of Guinardia blooms to understand the fate of these prominent organisms in marine systems.
Project description:No vaccines or antivirals are approved against Venezuelan equine encephalitis virus (VEEV) infection in humans. To improve our understanding of VEEV-host interactions, we simultaneously profiled host transcriptome and viral RNA (vRNA) in thousands of single cells during infection of human astrocytes. Host transcription was suppressed, and “superproducer cells” with extreme vRNA abundance and altered transcriptome emerged during the first viral life cycle. Cells with increased structural-to-nonstructural transcript ratio demonstrated upregulation of trafficking genes at later time points. Loss- and gain-of-function experiments confirmed pro- and antiviral host factors. Single-cell deep sequencing analysis identified a viral E3 protein mutation altering host gene expression. Lastly, comparison with data from other viruses highlighted common and unique pathways perturbed by infection across evolutionary scales. This study provides a high-resolution characterization of the cellular response to VEEV infection, identifies candidate targets for antivirals, and establishes a comparative single-cell approach to study the evolution of virus-host interactions.
Project description:Contributions of the viral component of the microbiome, the virome, to the development of innate and adaptive immunity are largely unknown. In this study, we systematically defined the tissue host response to a panel of eukaryotic enteric viruses inducing asymptomatic infection in mice. Small intestinal and colon transcriptomes from GF mice were compared to the ones from germ-free mice mono-infected with each of the viruses in the panel. This transcriptional profiling unveiled general adaptations by the host as well as numerous viral strain-specific responses that persist.
Project description:A single hematopoietic stem cell can give rise to all blood cells with remarkable fidelity. Here, we define the chromatin accessibility and transcriptional landscape controlling this process in thirteen primary cell types that traverse the hematopoietic hierarchy. Exploiting the finding that enhancer landscapes better reflect cell identity than mRNA levels, we enable "enhancer cytometry" for accurate enumeration of pure cell types from complex populations. We further reveal the lineage ontogeny of genetic elements linked to diverse human diseases. In acute myeloid leukemia, chromatin accessibility reveals distinctive regulatory evolution in pre-leukemic HSCs (pHSCs), leukemia stem cells, and leukemic blasts. These leukemic cells demonstrate unique lineage infidelity, confirmed by single cell regulomes. We further show that pHSCs have a competitive advantage that is conferred by reduced chromatin accessibility at HOXA9 targets and is associated with adverse patient outcomes. Thus, regulome dynamics can provide diverse insights into human hematopoietic development and disease. Single-cell ATAC-seq of LMPPs, Monocytes, LSCs and Luekemic blast cells.
Project description:Purpose: Next-generation transcriptome sequencing was done to understand host and eukaryotic microbiome changes in gene expression in association with defined insecticide selection pressures. The specific goal of this research was to understand whole-body physiological responses in German cockroaches and associated microbiota, at the metatranscriptome level, to defined insecticide selection pressures. Methods: We used the insecticide indoxacarb as the selecting insecticide, which is an important bait active ingredient for cockroach control. Six generations of selection with indoxacarb bait produced a strain with substantial (>20x) resistance relative to inbred control lines originating from the same parental stock. Results: Metatranscriptome sequencing revealed 1123 significantly differentially expressed genes in > two of three statistical models (81 upregulated and 1042 downregulated; FDR p<0.001; log2FC of +/- 1). The majority of upreglated genes were from the host cockroach while the majority of downregulated genes were from associated viruses and the eukaryotic microbiome. Conclusions: We show here significant impacts by insecticide selection on not only host stress-respnses like detoxification, but also on clearace of microbial parasites, pathogens, commensals and/or symbionts.
Project description:Extra-chromosomal selfish DNA elements can evade the risk of being lost at every generation by behaving as chromosome appendages, thereby ensuring high fidelity segregation and stable persistence in host cell populations. The yeast 2-micron plasmid and episomes of the mammalian gammaherpes and papilloma viruses that tether to chromosomes and segregate by hitchhiking on them exemplify this strategy. We document for the first time the utilization of a SWI/SNF type chromatin remodeling complex as a conduit for chromosome association by a selfish element. One principal mechanism for chromosome tethering by the 2-micron plasmid is the bridging interaction of the plasmid partitioning proteins (Rep1 and Rep2) with the yeast RSC2 complex and the plasmid partitioning locus STB. We substantiate this model by multiple lines of evidence derived from genomics, cell biology and in vivo and in vitro interaction analyses. We describe a Rep-STB bypass system in which a plasmid non-covalently associated with the RSC complex mimics segregation by chromosome hitchhiking. Given the ubiquitous prevalence of SWI/SNF family chromatin remodeling complexes among eukaryotes, it is likely that the 2-micron plasmid paradigm or analogous ones will be encountered among other eukaryotic selfish elements.
Project description:Microbial genome-wide association studies (GWAS) have uncovered numerous host genetic variants associated with gut microbiota. However, links between host genetics, the gut microbiome and specific cellular context remains unclear. Here, we use a computational framework, scBPS (single-cell Bacteria Polygenic Score), to integrate existing microbial GWAS and single-cell RNA-sequencing profiles of 24 human organs, including the liver, pancreas, lung, and intestine, to identify host tissues and cell types relevant to gut microbes. Analyzing 207 microbial taxa and 254 host cell types, scBPS-inferred cellular enrichments confirmed known biology such as dominant communications between gut microbes and the digestive tissue module and liver epithelial cell compartment. scBPS also identified a robust association between Collinsella and central-veinal hepatocyte subpopulation. We experimentally validated the causal effects of Collinsella on cholesterol metabolism in mice through single-nuclei RNA sequencing on liver tissue to identify relevant cell subpopulations. Mechanistically, oral gavage of Collinsella modulated cholesterol pathway gene expression in central-veinal hepatocytes. We further validated our approach using independent microbial GWAS data, alongside single-cell and bulk transcriptomic analyses, demonstrating its robustness and reproducibility. Together, scBPS enables a systematic mapping of the host-microbe crosstalk by linking cell populations to their interacting gut microbes.
Project description:This SuperSeries is composed of the following subset Series: GSE35462: Genome-wide analysis of histone methylation reveals chromatin state-based regulation of host cellular gene expression induced by hepatitis B viruses (ChIP-Seq dataset) GSE35464: Genome-wide analysis of histone methylation reveals chromatin state-based regulation of host cellular gene expression induced by hepatitis B viruses (DGE dataset) Refer to individual Series
Project description:A single hematopoietic stem cell can give rise to all blood cells with remarkable fidelity. Here, we define the chromatin accessibility and transcriptional landscape controlling this process in thirteen primary cell types that traverse the hematopoietic hierarchy. Exploiting the finding that enhancer landscapes better reflect cell identity than mRNA levels, we enable "enhancer cytometry" for accurate enumeration of pure cell types from complex populations. We further reveal the lineage ontogeny of genetic elements linked to diverse human diseases. In acute myeloid leukemia, chromatin accessibility reveals distinctive regulatory evolution in pre-leukemic HSCs (pHSCs), leukemia stem cells, and leukemic blasts. These leukemic cells demonstrate unique lineage infidelity, confirmed by single cell regulomes. We further show that pHSCs have a competitive advantage that is conferred by reduced chromatin accessibility at HOXA9 targets and is associated with adverse patient outcomes. Thus, regulome dynamics can provide diverse insights into human hematopoietic development and disease. ATAC-seq profiles of hematopoietic and leukemic cell types, across 13 normal hematopoietic cell types and 3 acute myeloid leukemia cell types. The complete data set contains a total of 132 samples.