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:BACKGROUND Enteric glia contribute to the pathophysiology of various intestinal immune-driven diseases, such as postoperative ileus (POI), a motility disorder and common complication after abdominal surgery. Enteric gliosis of the intestinal muscularis externa (ME) has been identified as part of POI development. However, the glia-restricted responses and activation mechanisms are poorly understood. The sympathetic nervous system becomes rapidly activated by abdominal surgery. It modulates intestinal immunity, innervates all intestinal layers, and directly interfaces with enteric glia. We hypothesized that sympathetic innervation controls enteric glia reactivity in response to surgical trauma. METHODS Sox10iCreERT2/Rpl22HA/+ mice were subjected to a mouse model of laparotomy or intestinal manipulation to induce POI. Histological, protein, and transcriptomic analyses were performed to analyze glia-specific responses. Interactions between the sympathetic nervous system and enteric glia were studied in mice chemically depleted of TH+ sympathetic neurons and glial-restricted Sox10iCreERT2/JellyOPfl/+/Rpl22HA/+ mice, allowing optogenetic stimulation of β-adrenergic downstream signaling and glial-specific transcriptome analyses. A laparotomy model was used to study the effect of sympathetic signaling on enteric glia in the absence of intestinal manipulation. Mechanistic studies included adrenergic receptor expression profiling in vivo and in vitro and adrenergic agonism treatments of primary enteric glial cell cultures to elucidate the role of sympathetic signaling in acute enteric gliosis and POI. RESULTS With ~4000 differentially expressed genes, the most substantial enteric glia response occurs early after intestinal manipulation. During POI, enteric glia switch into a reactive state and continuously shape their microenvironment by releasing inflammatory and migratory factors. Sympathetic denervation reduced the inflammatory response of enteric glia in the early postoperative phase. Optogenetic and pharmacological stimulation of β-adrenergic downstream signaling triggered enteric glia reactivity. Finally, distinct adrenergic agonists revealed β-1/2 adrenoceptors as the molecular targets of sympathetic–driven enteric glial reactivity. CONCLUSIONS Enteric glia act as early responders during post-traumatic intestinal injury and inflammation. Intact sympathetic innervation and active β-adrenergic receptor signaling in enteric glia is a trigger of the immediate glial postoperative inflammatory response. With immune-activating cues originating from the sympathetic nervous system as early as the initial surgical incision, adrenergic signaling in enteric glia presents a promising target for preventing POI development.
Project description:Glial cells have been proposed as an endogenous source of progenitors for the treatment of neural deficits. However, the cellular and molecular mechanisms underpinning the neurogenic potential of certain populations of adult glial cells, are not known. Using single cell transcriptomic profiling, we show here that enteric glial cells represent a cell state attained by autonomic neural crest cells as they transition during development along a linear default differentiation trajectory that allows them to retain neurogenic potential while acquiring a gene expression profile associated with their role in neuronal support and immunomodulation. Key neurogenic loci in early enteric nervous system progenitors remain in open chromatin configuration in mature enteric glia, thus facilitating neuronal differentiation under appropriate conditions. Molecular profiling and gene targeting of enteric glial cells in a novel cell culture system of enteric neurogenesis and a gut injury model, demonstrated that neuronal differentiation of glia is driven by transcriptional programs employed in vivo by early progenitors. Our work provides mechanistic insight into the dynamic regulatory landscape underpinning the development of intestinal neural circuits and generates a platform for advancing glial cells as therapeutic agents for the treatment of neural deficits.
Project description:Glial cells have been proposed as an endogenous source of progenitors for the treatment of neural deficits. However, the cellular and molecular mechanisms underpinning the neurogenic potential of certain populations of adult glial cells, are not known. Using single cell transcriptomic profiling, we show here that enteric glial cells represent a cell state attained by autonomic neural crest cells as they transition during development along a linear default differentiation trajectory that allows them to retain neurogenic potential while acquiring a gene expression profile associated with their role in neuronal support and immunomodulation. Key neurogenic loci in early enteric nervous system progenitors remain in open chromatin configuration in mature enteric glia, thus facilitating neuronal differentiation under appropriate conditions. Molecular profiling and gene targeting of enteric glial cells in a novel cell culture system of enteric neurogenesis and a gut injury model, demonstrated that neuronal differentiation of glia is driven by transcriptional programs employed in vivo by early progenitors. Our work provides mechanistic insight into the dynamic regulatory landscape underpinning the development of intestinal neural circuits and generates a platform for advancing glial cells as therapeutic agents for the treatment of neural deficits.
Project description:Glial cells have been proposed as an endogenous source of progenitors for the treatment of neural deficits. However, the cellular and molecular mechanisms underpinning the neurogenic potential of certain populations of adult glial cells, are not known. Using single cell transcriptomic profiling, we show here that enteric glial cells represent a cell state attained by autonomic neural crest cells as they transition during development along a linear default differentiation trajectory that allows them to retain neurogenic potential while acquiring a gene expression profile associated with their role in neuronal support and immunomodulation. Key neurogenic loci in early enteric nervous system progenitors remain in open chromatin configuration in mature enteric glia, thus facilitating neuronal differentiation under appropriate conditions. Molecular profiling and gene targeting of enteric glial cells in a novel cell culture system of enteric neurogenesis and a gut injury model, demonstrated that neuronal differentiation of glia is driven by transcriptional programs employed in vivo by early progenitors. Our work provides mechanistic insight into the dynamic regulatory landscape underpinning the development of intestinal neural circuits and generates a platform for advancing glial cells as therapeutic agents for the treatment of neural deficits.
Project description:IL-1 signaling in enteric glia initiates acute intestinal inflamation and modulates postoperative motility disturbances by triggering a reactive glial phenotype named enteric gliosis. Enteric glia modulate macrophage function and activity in this reactive state by releasing a unique panel of chemokines and cytokines. An enteric glia-selective knockout of this pathway ameliorates acute postoperative inflammation and prevents postoperative ileus.
Project description:Glial cells have been proposed as an endogenous source of progenitors for the treatment of neural deficits. However, the cellular and molecular mechanisms underpinning the neurogenic potential of certain populations of adult glial cells, are not known. Using single cell transcriptomic profiling, we show here that enteric glial cells represent a cell state attained by autonomic neural crest cells as they transition during development along a linear default differentiation trajectory that allows them to retain neurogenic potential while acquiring a gene expression profile associated with their role in neuronal support and immunomodulation. Key neurogenic loci in early enteric nervous system progenitors remain in open chromatin configuration in mature enteric glia, thus facilitating neuronal differentiation under appropriate conditions. Molecular profiling and gene targeting of enteric glial cells in a novel cell culture system of enteric neurogenesis and a gut injury model, demonstrated that neuronal differentiation of glia is driven by transcriptional programs employed in vivo by early progenitors. Our work provides mechanistic insight into the dynamic regulatory landscape underpinning the development of intestinal neural circuits and generates a platform for advancing glial cells as therapeutic agents for the treatment of neural deficits.
Project description:C. elegans has served as a laboratory model organism due to its ease of manipulation and the availability of both forward and reverse genetics. In recent years, efforts to study host-pathogen interactions in C. elegans have increased. For example, analysis of infections by bacteria such as Pseudomonas, Salmonella or Serratia has revealed the existence of innate immune pathways in C. elegans that are also conserved in vertebrates. To date, there has been no natural virus infection reported in C. elegans or C. briggsae. Here we describe evidence of natural virus infection in wild isolates of both C. elegans and C. briggsae. Two highly divergent but related RNA viruses in the family Nodaviridae, tentatively named Orsay nodavirus and Santeuil nodavirus, were detected and their genomes partially sequenced. Infected worm lysates passed through 0.2 um filters could be used to infect uninfected worms, which could be further passaged for many generations. Furthermore, the viruses were subject to processing by the RNAi machinery as evidenced by the detection of virally derived small RNAs. Infection of mutant worms defective in small RNA pathways yielded more robust levels of viral RNA as compared to infection of isogenic N2 reference worms. These data demonstrate that nodaviruses are natural parasites of nematodes in the wild. Further study of the interactions between these viruses and nematodes is likely to provide insight into the natural ecology of nematodes and may reveal novel innate immune mechanisms that respond to viral infection.
Project description:C. elegans has served as a laboratory model organism due to its ease of manipulation and the availability of both forward and reverse genetics. In recent years, efforts to study host-pathogen interactions in C. elegans have increased. For example, analysis of infections by bacteria such as Pseudomonas, Salmonella or Serratia has revealed the existence of innate immune pathways in C. elegans that are also conserved in vertebrates. To date, there has been no natural virus infection reported in C. elegans or C. briggsae. Here we describe evidence of natural virus infection in wild isolates of both C. elegans and C. briggsae. Two highly divergent but related RNA viruses in the family Nodaviridae, tentatively named Orsay nodavirus and Santeuil nodavirus, were detected and their genomes partially sequenced. Infected worm lysates passed through 0.2 um filters could be used to infect uninfected worms, which could be further passaged for many generations. Furthermore, the viruses were subject to processing by the RNAi machinery as evidenced by the detection of virally derived small RNAs. Infection of mutant worms defective in small RNA pathways yielded more robust levels of viral RNA as compared to infection of isogenic N2 reference worms. These data demonstrate that nodaviruses are natural parasites of nematodes in the wild. Further study of the interactions between these viruses and nematodes is likely to provide insight into the natural ecology of nematodes and may reveal novel innate immune mechanisms that respond to viral infection. Two small RNA libraries (18-30 nt) from nodavirus-infected and cured C. elegans wild isolate JU1580 were sequenced on the Illumina Genome Analyzer II platform. Samples were treated with tobacco acid pyrophosphatase to allow cloning of small RNA molecules with 5'-triphosphates. Each sample was labelled with a unique four base pair barcode and libraries were multiplexed together with a third library (not included in this submission). The multiplexed libraries were sequenced in triplicate.
Project description:This study was undertaken to define the molecular subtypes of cells within enteric neurospheres. Methods: We performed single-cell RNA sequencing on 3-dimensional neurosphere cultures derived from the small intestines of Plp1::GFP mice. These data show profiling results from the PLP1::GFP negative cell fraction ancillary to the positive fraction in series GSE184981. Results: We identify populations of enteric neurons and fibroblasts in the PLP1::GFP negative cell fraction of enteric neurospheres.