Background Large animal models, such as the dog, are increasingly being used for studying diseases including gastrointestinal (GI) disorders. Dogs share similar environmental, genomic, anatomical, and intestinal physiologic features with humans. To bridge the gap between commonly used animal models, such as rodents, and humans, and expand the translational potential of the dog model, we developed a three-dimensional (3D) canine GI organoid (enteroid and colonoid) system. Organoids have recently gained interest in translational research as this model system better recapitulates the physiological and molecular features of the tissue environment in comparison with two-dimensional cultures. Results Organoids were derived from tissue of more than 40 healthy dogs and dogs with GI conditions, including inflammatory bowel disease (IBD) and intestinal carcinomas. Adult intestinal stem cells (ISC) were isolated from whole jejunal tissue as well as endoscopically obtained duodenal, ileal, and colonic biopsy samples using an optimized culture protocol. Intestinal organoids were comprehensively characterized using histology, immunohistochemistry, RNA in situ hybridization, and transmission electron microscopy, to determine the extent to which they recapitulated the in vivo tissue characteristics. Physiological relevance of the enteroid system was defined using functional assays such as optical metabolic imaging (OMI), the cystic fibrosis transmembrane conductance regulator (CFTR) function assay, and Exosome-Like Vesicles (EV) uptake assay, as a basis for wider applications of this technology in basic, preclinical and translational GI research. We have furthermore created a collection of cryopreserved organoids to facilitate future research. Conclusions We establish the canine GI organoid systems as a model to study naturally occurring intestinal diseases in dogs and humans, and that can be used for toxicology studies, for analysis of host-pathogen interactions, and for other translational applications. Electronic supplementary material The online version of this article (10.1186/s12915-019-0652-6) contains supplementary material, which is available to authorized users.

Recreational and medical use of cannabis among human immunodeficiency virus (HIV)-infected individuals has increased in recent years. In simian immunodeficiency virus (SIV)-infected macaques, chronic administration of ⌬9 -tetrahydrocannabinol (⌬ 9 -THC) inhibited viral replication and intestinal inflammation and slowed disease progression. Persistent gastrointestinal disease/inflammation has been proposed to facilitate microbial translocation and systemic immune activation and promote disease progression. Cannabinoids including ⌬ 9 -THC attenuated intestinal inflammation in mouse colitis models and SIV-infected rhesus macaques. To determine if the anti-inflammatory effects of ⌬ 9 -THC involved differential microRNA (miRNA) modulation, we profiled miRNA expression at 14, 30, and 60 days postinfection (days p.i.) in the intestine of uninfected macaques receiving ⌬ 9 -THC (n ‫؍‬ 3) and SIV-infected macaques administered either vehicle (VEH/ SIV; n ‫؍‬ 4) or THC (THC/SIV; n ‫؍‬ 4). Chronic ⌬ 9 -THC administration to uninfected macaques significantly and positively modulated intestinal miRNA expression by increasing the total number of differentially expressed miRNAs from 14 to 60 days p.i. At 60 days p.i., ϳ28% of miRNAs showed decreased expression in the VEH/SIV group compared to none showing decrease in the THC/SIV group. Furthermore, compared to the VEH/SIV group, THC selectively upregulated the expression of miR-10a, miR-24, miR-99b, miR-145, miR-149, and miR-187, previously been shown to target proinflammatory molecules. NOX4, a potent reactive oxygen species generator, was confirmed as a direct miR-99b target. A significant increase in NOX4 ؉ crypt epithelial cells was detected in VEH/SIV macaques compared to the THC/SIV group. We speculate that miR-99b-mediated NOX4 downregulation may protect the intestinal epithelium from oxidative stress-induced damage. These results support a role for differential miRNA induction in THC-mediated suppression of intestinal inflammation. Whether similar miRNA modulation occurs in other tissues requires further investigation. IMPORTANCE Gastrointestinal (GI) tract disease/inflammation is a hallmark of HIV/SIV infection. Previously, we showed that chronic treatment of SIV-infected macaques with ⌬9 -tetrahydrocannabinol (⌬ 9 -THC) increased survival and decreased viral replication and infection-induced gastrointestinal inflammation. Here, we show that chronic THC administration to SIV-infected macaques induced an anti-inflammatory microRNA expression profile in the intestine at 60 days p.i. These included several miRNAs bioinformatically predicted to directly target CXCL12, a chemokine known to regulate lymphocyte and macrophage trafficking into the intestine. Specifically, miR-99b was significantly upregulated in THC-treated SIV-infected macaques and confirmed to directly target NADPH oxidase 4 (NOX4), a reactive oxygen species generator known to damage intestinal epithelial cells. Elevated miR-99b expression was associated with a significantly decreased number of NOX4...

HIV replication and the cellular miRNA machinery interconnect at several post-transcriptional levels. To understand their regulatory role in the intestine, a major site of HIV/SIV replication, dissemination and CD4+ T cell depletion we profiled miRNA expression in colon following SIV infection (10-Acute-SIV, 5-uninfected). Nine (4-up and 5-down) miRNAs showed statistically significant differential expression. Most notably, miR-190b expression showed high statistical significance (Adjusted p=0.0032), the greatest fold change and was markedly elevated in colon and jejunum throughout SIV infection. Additionally, miR-190b upregulation was detected before peak viral replication and the nadir of CD4+ T cell depletion predominantly in lamina propria leukocytes. Interestingly non-SIV-infected macaques with diarrhea and colitis failed to upregulate miR-190b suggesting that its upregulation was neither inflammation nor immune-activation driven. SIV infection of in vitro cultured CD4+ T cells and primary intestinal macrophages conclusively identified miR-190b upregulation to be driven in response to viral replication. Further miR-190b expression levels in colon and jejunum positively correlated with tissue viral loads. In contrast, mRNA expression of MTMR6, a negative regulator of CD4+ T cell activation/proliferation significantly decreased in SIV-infected macrophages. Luciferase reporter assays confirmed MTMR6 as a direct miR-190b target. This first report describing dysregulated miRNA expression in the intestine identifies a potentially significant role for miR-190b in HIV/SIV pathogenesis. More importantly, miR-190b mediated MTMR6 downregulation suggests an important mechanism that could keep infected cells in an activated state thereby promoting viral replication. In future, the mechanisms driving miR-190b upregulation including other cellular processes it regulates in SIV-infected cells needs determination.

Diabetes mellitus (DM) in humans has recently been associated with altered intestinal microbiota. The consequences of intestinal dysbiosis, such as increased intestinal permeability and altered microbial metabolites, are suspected to contribute to the host inflammatory state and peripheral insulin resistance. Human diabetics have been shown to have changes in bile acid (BA) metabolism which may be detrimental to glycemic control. The purpose of this study was to examine BA metabolism in dogs with naturally-occurring, insulin-dependent DM and to relate these findings to changes in the intestinal microbiota. A prospective observational study of adult dogs with a clinical diagnosis of DM ( n = 10) and healthy controls (HC, n = 10) was performed. The fecal microbiota were analyzed by 16S rRNA gene next-generation (Illumina) sequencing. Concentrations of fecal unconjugated BA (fUBA) were measured using gas chromatography and mass spectrometry. Analysis of bacterial communities showed no significant difference for any of the alpha-diversity measures between DM vs. HC dogs. Principal coordinate analysis based on unweighted Unifrac distance metric failed to show significant clustering between dog groups (ANOSIM Unweighted : R = 0.084; p = 0.114). However, linear discriminate analysis effects size (LEfSe) detected differentially abundant bacterial taxa (α = 0.01, LDA score >2.0) on various phylogenetic levels. While Enterobacteriaceae was overrepresented in dogs with DM, the proportions of Erysipelotrichia, Mogibacteriaceae , and Anaeroplasmataceae were increased in HC dogs. Dogs with DM had increased concentration of total primary fUBA compared to HC dogs ( p = 0.028). The concentrations of cholic acid and the cholic acid percentage of the total fUBA were increased ( p = 0.028 and p = 0.035, respectively) in the feces of DM dogs relative to HC dogs. The levels of lithocholic acid (both absolute value and percentage of the total fUBA) were decreased ( p = 0.043 and p < 0.01, respectively) in DM dogs vs. HC dogs. Results indicate that dogs with DM have both intestinal dysbiosis and associated fUBA alterations. The pattern of dysbiosis and altered BA composition is similar to that seen in humans with Type 2 DM. The dog represents a novel large animal model for advancing translational medicine research efforts (e.g., investigating pathogenesis and therapeutics) in DM affecting humans.

Lipopolysaccharide (LPS) is associated with chronic intestinal inflammation and promotes intestinal cancer progression in the gut. While the interplay between LPS and intestinal immune cells has been well-characterized, little is known about LPS and the intestinal epithelium interactions. In this study, we explored the differential effects of LPS on proliferation and the transcriptome in 3D enteroids/colonoids obtained from dogs with naturally occurring gastrointestinal (GI) diseases including inflammatory bowel disease (IBD) and intestinal mast cell tumor. The study objective was to analyze the LPS-induced modulation of signaling pathways involving the intestinal epithelia and contributing to colorectal cancer development in the context of an inflammatory (IBD) or a tumor microenvironment. While LPS incubation resulted in a pro-cancer gene expression pattern and stimulated proliferation of IBD enteroids and colonoids, downregulation of several cancer-associated genes such as Gpatch4, SLC7A1, ATP13A2, and TEX45 was also observed in tumor enteroids. Genes participating in porphyrin metabolism (CP), nucleocytoplasmic transport (EEF1A1), arachidonic acid, and glutathione metabolism (GPX1) exhibited a similar pattern of altered expression between IBD enteroids and IBD colonoids following LPS stimulation. In contrast, genes involved in anion transport, transcription and translation, apoptotic processes, and regulation of adaptive immune responses showed the opposite expression patterns between IBD enteroids and colonoids following LPS treatment. In brief, the crosstalk between LPS/TLR4 signal transduction pathway and several metabolic pathways such as primary bile acid biosynthesis and secretion, peroxisome, renin–angiotensin system, glutathione metabolism, and arachidonic acid pathways may be important in driving chronic intestinal inflammation and intestinal carcinogenesis.

No abstract

No abstract

1 Background: Large animal models, such as the dog, are increasingly being used over 2 rodent models for studying naturally occurring diseases including gastrointestinal (GI) 3 disorders. Dogs share similar environmental, genomic, anatomical, and intestinal 4 physiologic features with humans. To bridge the gap between currently used animal 5 models (e.g. mouse) and humans, and expand the translational potential of the dog 6 model, we developed a three dimensional (3D) canine GI organoid (enteroid and 7 colonoid) system. Organoids have recently gained interest in translational research as 8 this model system better recapitulates the physiological and molecular features of the 9 tissue environment in comparison with two-dimensional cultures.