scholarly journals Multiplexed biosensors for precision bacteria tropism in vivo

2019 ◽  
Author(s):  
Tiffany Chien ◽  
Tetsuhiro Harimoto ◽  
Benjamin Kepecs ◽  
Kelsey Gray ◽  
Courtney Coker ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastrointestinal Tract ◽  
Bacterial Growth ◽  
Essential Gene ◽  
Logic Gate ◽  
Control Mechanisms ◽  
Lower Gastrointestinal Tract

AbstractThe engineering of microbes spurs biotechnological innovations, but requires control mechanisms to confine growth within defined environments for translation. Here we engineer bacterial growth tropism to sense and grow in response to specified oxygen, pH, and lactate signatures. Coupling biosensors to drive essential gene expression reveals engineered bacterial localization within upper or lower gastrointestinal tract. Multiplexing biosensors in an AND logic-gate architecture reduced bacterial off-target colonization in vivo.

scholarly journals Transcriptomic profiling of high-density Giardia foci encysting in the murine proximal intestine

2017 ◽  
Author(s):  
JK Pham ◽  
C Nosala ◽  
EY Scott ◽  
KF Nguyen ◽  
KD Hagen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastrointestinal Tract ◽  
Diarrheal Disease ◽  
Axenic Culture ◽  
Laboratory Culture ◽  
High Density ◽  
Live Animal ◽  
Mammalian Cell Lines ◽  
Proximal Intestine

AbstractGiardiais a highly prevalent, understudied protistan parasite causing significant diarrheal disease worldwide. Its life cycle consists of two stages: infectious cysts ingested from contaminated food or water sources, and motile trophozoites that colonize and attach to the gut epithelium, later encysting to form new cysts that are excreted into the environment. Current understanding of parasite physiology in the host is largely inferred from transcriptomic studies usingGiardiagrown axenically or in co-culture with mammalian cell lines. The dearth of information about the diversity of host-parasite interactions occurring within distinct regions of the gastrointestinal tract has been exacerbated by a lack of methods to directly and non-invasively interrogate disease progression and parasite physiology in live animal hosts. By visualizingGiardiainfections in the mouse gastrointestinal tract using bioluminescent imaging (BLI) of tagged parasites, we recently showed that parasites colonize the gut in high-density foci that may cause localized pathology to the epithelium. Encystation is also initiated in these foci throughout the entire course of infection, yet how the physiology of parasites within high-density foci in the host gut differs from that of cells in laboratory culture is unclear. Here we use BLI to precisely select parasite samples from high-density foci in the proximal intestine to interrogatein vivo Giardiagene expression in the host. Relative to axenic culture, we noted significantly higher expression (> 10-fold) of oxidative stress, membrane transporter, and metabolic and structural genes associated with encystation in the high-density foci. These differences in gene expression within parasite foci in the host may reflect physiological changes associated with high-density growth in localized regions of the gut. We also identified and verified six novel cyst-specific proteins, including new components of the cyst wall that were highly expressed in these foci. Ourin vivotranscriptome data support an emerging view that parasites encyst early in localized regions in the gut, possibly as a consequence of nutrient limitation, and also impact local metabolism and physiology.

scholarly journals In vivo near-infrared dual-axis confocal microendoscopy in the human lower gastrointestinal tract

2012 ◽  
Vol 17 (02) ◽  
pp. 1 ◽  
Author(s):  
Wibool Piyawattanametha ◽  
Hyejun Ra ◽  
Kevin E. Loewke ◽  
Michael J. Mandella ◽  
Christopher H. Contag ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Near Infrared ◽  
Lower Gastrointestinal Tract

scholarly journals The Nestin neural enhancer is essential for normal levels of endogenous Nestin in neuroprogenitors but is not required for embryo development

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0258538
Author(s):  
Ella Thomson ◽  
Ruby Dawson ◽  
Chee Ho H’ng ◽  
Fatwa Adikusuma ◽  
Sandra Piltz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Embryonic Development ◽  
Large Scale ◽  
Cultured Cells ◽  
Essential Gene ◽  
Protein Localization ◽  
Regulatory Elements ◽  
Vast Number ◽  
Enhancer Region

Enhancers are vitally important during embryonic development to control the spatial and temporal expression of genes. Recently, large scale genome projects have identified a vast number of putative developmental regulatory elements. However, the proportion of these that have been functionally assessed is relatively low. While enhancers have traditionally been studied using reporter assays, this approach does not characterise their contribution to endogenous gene expression. We have studied the murine Nestin (Nes) intron 2 enhancer, which is widely used to direct exogenous gene expression within neural progenitor cells in cultured cells and in vivo. We generated CRISPR deletions of the enhancer region in mice and assessed their impact on Nes expression during embryonic development. Loss of the Nes neural enhancer significantly reduced Nes expression in the developing CNS by as much as 82%. By assessing NES protein localization, we also show that this enhancer region contains repressor element(s) that inhibit Nes expression within the vasculature. Previous reports have stated that Nes is an essential gene, and its loss causes embryonic lethality. We also generated 2 independent Nes null lines and show that both develop without any obvious phenotypic effects. Finally, through crossing of null and enhancer deletion mice we provide evidence of trans-chromosomal interaction of the Nes enhancer and promoter.

scholarly journals Advances in In-Vivo Imaging of Inflammatory Bowel Disease Mediators

2018 ◽  
Author(s):  
Nicole Dmochowska ◽  
Hannah R. Wardill ◽  
Patrick A. Hughes
Keyword(s):  
Inflammatory Bowel Disease ◽  
Immune Response ◽  
Gastrointestinal Tract ◽  
Inflammatory Mediators ◽  
Bowel Disease ◽  
Lower Gastrointestinal Tract ◽  
Recent Developments ◽  
Inflammatory Bowel ◽  
Environmental Antigen

Inflammatory Bowel Disease (IBD) is characterized by chronic remitting and relapsing inflammation of the lower gastrointestinal tract. The etiology underlying IBD remains unknown but is thought to involve a hypersensitive immune response to environmental antigen, including the microbiota. Diagnosis and monitoring of disease is heavily reliant on endoscopy, which is invasive and does not provide information regarding specific mediators. This review describes recent developments in imaging of IBD with a focus on PET and SPECT imaging of inflammatory mediators, and how this may be applied to the microbiota.

scholarly journals The Nestin neural enhancer is essential for normal levels of endogenous Nestin in neuroprogenitors but is not required for embryo development

2021 ◽  
Author(s):  
Ella Thomson ◽  
Ruby Dawson ◽  
Chee Ho H'ng ◽  
Fatwa Adikusuma ◽  
Sandra Piltz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Embryonic Development ◽  
Large Scale ◽  
Cultured Cells ◽  
Essential Gene ◽  
Protein Localization ◽  
Regulatory Elements ◽  
Vast Number ◽  
Enhancer Region

Enhancers are vitally important during embryonic development to control the spatial and temporal expression of genes. Recently, large scale genome projects have identified a vast number of putative developmental regulatory elements. However, the proportion of these that have been functionally assessed is relatively low. While enhancers have traditionally been studied using reporter assays, this approach does not characterise their contribution to endogenous gene expression. We have studied the murine Nestin (Nes) intron 2 enhancer, which is widely used to direct exogenous gene expression within neural progenitor cells in cultured cells and in vivo. We generated CRISPR deletions of the enhancer region in mice and assessed their impact on Nes expression during embryonic development. Loss of the Nes neural enhancer significantly reduced Nes expression in the developing CNS by as much as 82%. By assessing NES protein localization, we also show that this enhancer region contains repressor element(s) that inhibit Nes expression within the vasculature. Previous reports have stated that Nes is an essential gene, and its loss causes embryonic lethality. We also generated 2 independent Nes null lines and show that both develop without any obvious phenotypic effects. Finally, through crossing of null and enhancer deletion mice we provide evidence of trans-chromosomal interaction of the Nes enhancer and promoter.

scholarly journals Development of a porcine model for assessment of mucosal repair following endoscopic resection of the lower gastrointestinal tract

2017 ◽  
Vol 05 (10) ◽  
pp. E1014-E1019 ◽  
Author(s):  
Nicolas Etchepare ◽  
Jérémy Bregeon ◽  
Lucille Quénéhervé ◽  
Sami Haddara ◽  
Yann Touchefeu ◽  
...  
Keyword(s):  
Wound Healing ◽  
Gastrointestinal Tract ◽  
Porcine Model ◽  
Colorectal Polyps ◽  
Lower Gastrointestinal Tract ◽  
Mucosal Repair ◽  
Histological Data ◽  
Fibrin Deposit ◽  
Mucosal Wound

Abstract Background and aims Endoscopic mucosal resection (EMR) is widely performed for the treatment of colorectal polyps. However, the pathophysiological mechanisms of mucosal repair, including in situations at high risk of post-polypectomy bleeding, remain largely unknown. The objective of our study was to develop a porcine model of EMR in the lower gastrointestinal tract to monitor mucosal wound healing over time. Methods Under general anesthesia, five large wounds were created in the lower gastrointestinal tract at different times, i. e. at day 0, 3, 7, 10, and 14, by multiband EMR, in each of the six pigs in the study. A colorectal resection was performed at day 14 and the animal euthanized. Repeated endoscopic and endomicroscopic examination, and histological analysis were performed. Results No complications occurred and all animals reached the study end point. The endoscopic aspect of wound healing evolved into different phases with first a fibrin deposit covering the wounds which then gave way to granulomatous tissue. The size of the wound regressed significantly as early as day 3. Re-epithelialization of the wound started from day 7, and neo-mucosal crypts appeared from day 10. The endomicroscopic analysis described a ‘ground glass appearance’ from day 3 and irregular crypts from day 10, which was consistent with histological data. Good agreement between macroscopic, endomicroscopic, and histological parameters of mucosal wound healing was observed in vivo. Conclusion This study demonstrates for the first time the feasibility of an experimental in vivo porcine model of lower gastrointestinal endoscopic resections to monitor tissue repair. This model might be helpful to document pharmacological approaches for preventing complications of endoscopic procedures performed in humans.

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