Colon Samples Research Articles

A novel oral formulation of the melanocortin-1 receptor agonist PL8177 resolves inflammation in preclinical studies of inflammatory bowel disease and is gut restricted in rats, dogs, and humans.

PL8177 is a potent and selective agonist of the melanocortin 1 receptor (MC1R). PL8177 has shown efficacy in reversing intestinal inflammation in a cannulated rat ulcerative colitis model. To facilitate oral delivery, a novel, polymer-encapsulated formulation of PL8177 was developed. This formulation was tested in 2 rat ulcerative colitis models and evaluated for distribution, in vivo, in rats, dogs, and humans. The rat models of colitis were induced by treatment with 2,4-dinitrobenzenesulfonic acid or dextran sulfate sodium. Single nuclei RNA sequencing of colon tissues was performed to characterize the mechanism of action. The distribution and concentration of PL8177 and the main metabolite within the GI tract after a single oral dose of PL8177 was investigated in rats and dogs. A phase 0 clinical study using a single microdose (70 µg) of [14C]-labeled PL8177 investigated the release of PL8177 in the colon of healthy men after oral administration. Rats treated with 50 µg oral PL8177 demonstrated significantly lower macroscopic colon damage scores and improvement in colon weight, stool consistency, and fecal occult blood vs the vehicle without active drug. Histopathology analysis resulted in the maintenance of intact colon structure and barrier, reduced immune cell infiltration, and increased enterocytes with PL8177 treatment. Transcriptome data show that oral PL8177 50 µg treatment causes relative cell populations and key gene expressions levels to move closer to healthy controls. Compared with vehicle, treated colon samples show negative enrichment of immune marker genes and diverse immune-related pathways. In rats and dogs, orally administered PL8177 was detected at higher amounts in the colon vs upper GI tract. [14C]-PL8177 and the main metabolite were detected in the feces but not in the plasma and urine in humans. This suggests that the parent drug [14C]-PL8177 was released from the polymer formulation and metabolized within the GI tract, where it would be expected to exert its effect. Collectively, these findings support further research into the oral formulation of PL8177 as a possible therapeutic for GI inflammatory diseases in humans.

Gut virome-colonising Orthohepadnavirus genus is associated with ulcerative colitis pathogenesis and induces intestinal inflammation in vivo

ObjectivesUlcerative colitis (UC) is a chronic inflammatory disorder of unknown aetiology. Gut virome dysbiosis is fundamental in UC progression, although its role in the early phases of the disease is...

Long-term 1,2-dimethylhydrazine triggers pathological remodeling of colon mucosa through repression of sestrin2, nuclear factor (erythroid-derived 2)-like 2, and sirtuin4 stimulating mitochondrial stress and metabolic reprogramming.

1,2-Dimethylhydrazine (DMH) is a plant toxicant that enters the food web through the diet. It is biotransformed into azoxymethane, a colon carcinogen, during the first hepatic passage. In mice, this study assessed the role of glutamate dehydrogenase (GDH), a key glutaminolysis enzyme in DMH-induced colorectal cancer (CRC). Colon samples were taken from mice given 6 or 15 weekly doses of 20mg/kg DMH and serially sacrificed. Repeated DMH doses induced early aberrant crypt foci that evolved into irreversible adenocarcinomas over 24weeks, along with an increase in GDH and lactate dehydrogenase activities (+ 122%, + 238%, P < 0.001), indicating a switch to aerobic glycolysis and glutaminolysis. Transcriptional downregulation of the endogenous GDH inhibitor, sirtuin4, and two redox regulators, mitochondrial sestrin2 and nuclear factor (erythroid derivative 2)-like 2 (- 26% and - 22%, P < 0, 05; and - 30%, P < 0.01), exacerbated mitochondrial stress by boosting mitochondrial superoxide dismutase activity (+ 240% (P < 0.001) while depressing catalase activity and GSH levels (- 57% and - 60%, P < 0.001). In vitro, allosteric GDH inhibition by 50µM epigallocatechin gallate decreased human carcinoma (HCT-116) cells' viability, clonogenicity, and migration (- 43% and - 57%, P < 0.001, 41%, P < 0.05), while stimulating ROS release (+ 57%, P < 0.001). Dimethylfumarate (DMF), a linear electrophile and mitochondrial fumarate analog, rebalanced ROS levels (- 34%, P < 0.05) and improved GDH activity, cell viability, and tumorogenic capacity (+ 20%, 20%, P < 0.001; and 33%, P < 0.05). Thus, the pathological remodeling of colon mucosa is supported by metabolic reprogramming bypassing uncoupled mitochondria. DMF highlights the critical role of electrophile response elements in modulating redox mithormesis and redox homeostasis during CRC.

Colorectal endoscopic submucosal dissection using a concealable robotic add-on device: A comparative in vivo feasibility study.

128 Background: Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe colonic endoscopic submucosal dissection (ESD). In this preclinical ex vivo and in vivo animal study, we developed a concealable robotic-assisted traction device and evaluated its performance in colorectal ESD. Methods: An experienced endoscopist performed ESD on an ex vivo porcine colon 18 times using our robot and 18 times using the conventional method. The outcome measures were procedure time, dissection speed, procedure-related adverse events, and blind dissection rate. We also conducted an in vivo feasibility study in live pigs. Robotic ESD was performed by experienced and novice endoscopist groups (n = 2, each). The outcomes included time to complete each ESD step, total procedure time, size of the dissected mucosa, rate of en bloc resection, and major adverse events. Results: Thirty-six colonic lesions were resected from ex vivo porcine colon samples. The total procedure time was significantly shorter in robotic ESD (RESD) than in conventional ESD (CESD) (20.1±4.1 vs. 34.3±8.3; P &lt; 0.05). The submucosal dissection speed was significantly higher in the RESD group than in the CESD group (36.8±9.2 vs. 18.1±4.7; P &lt; 0.05). The blind dissection rate was also significantly lower in the robotic group (12.8±3.4% vs. 35.1±3.9%; P &lt; 0.05). In an in vivo feasibility study, the robot was attached to the colonoscope and successfully inserted into the proximal colon without damaging the colonic wall, and ESD was successfully performed. There was no significant difference in the submucosal dissection speed between the groups (P = 0.465). Conclusions: When the concealable robot assisted the colonic ESD procedure, the dissection speed and safety profile improved significantly. Thus, our robotic device can provide a simple, effective, and safe multidirectional traction during colonic ESD. When the robot was assisting in the ESD procedure, the dissection speed improved significantly, especially in the novice endoscopists.

Influence of Butyrate on Impaired Gene Expression in Colon from Patients with High Blood Pressure.

Hypertension (HTN) is associated with gut dysbiosis and the depletion of butyrate-producing bacteria in animal models and people. Furthermore, fecal material transfer from donor hypertensive patients increases blood pressure in normotensive recipient animals and ameliorates HTN-associated pathophysiology. These observations have implications in the impaired interactions between the gut and gut microbiota in HTN. Although this concept is supported in animal models, little is known about human HTN. Therefore, our objective for this study was to compare gene expression with transcriptomics and its potential to influence microbiota in subjects with normal and high blood pressure (HBP). Colon samples from reference subjects with normal blood pressure (REF) and HBP were used for RNA-seq to analyze their transcriptomes. We observed the significant downregulation of gene sets governing immune responses (e.g., SGK1 and OASL), gut epithelial function (e.g., KRT20 and SLC9A3R1), gut microbiota (e.g., PPARG and CIDEC) and genes associated with cardiovascular and gut diseases (e.g., PLAUR and NLN) in HBP subjects; the expression of genes within these pathways correlated with blood pressure. Potential drug targets in the gut epithelium were identified using the Drug Gene International Database for possible use in HTN. They include peroxisome proliferator-activated receptor gamma (PPRG), active serum/glucocorticoid regulated kinase 1 (SGK1) and 3 beta-hydroxysteroid isomerase type II inhibitor (HSD3B). Finally, butyrate, a microbiota-derived short-chain fatty acid, restored the disrupted expression of certain functional genes in colonic organoids from HBP subjects. Patients with HBP exhibit a unique transcriptome that could underlie impaired gut-microbiota interactions. Targeting these interactions could provide a promising new therapeutic intervention for hypertension management.

P110 activation protein is strongly expressed in intestinal fibrosis in inflammatory bowel disease patients

Abstract Background Intestinal fibrosis is a common complication of inflammatory bowel disease (IBD) with limited diagnostic modalities to detect and determine the degree of fibrosis. Fibroblast activation protein alpha (FAP) is a protein with both dipeptidyl peptidase and endopeptidase properties which is virtually absent in healthy tissues and has increased expression in chronic inflammatory and fibrotic diseases. In this study, we investigated the presence of FAP in intestinal fibrosis caused by Crohn’s disease (CD) and ulcerative colitis (UC). Methods For this study, transmural surgical resection specimens were retrieved from the Tytgat institute IBD biobank located at Amsterdam University Medical Center. IBD patients undergoing an ileocecal resection for stricturing CD or a subtotal colectomy for therapy-refractory disease, and patients undergoing a right-sided hemicolectomy or ileocecal resection for dysplasia or non-metastasized colorectal cancer (CRC), were included. All patients had an established diagnosis of (CD, UC, dysplasia or CRC) by previous endoscopy and biopsies and had provided informed consent prior to surgery. FAP protein and gene expression levels were determined using immunohistochemistry staining and quantitative polymerase chain reaction (qPCR). Mass cytometry was used to identify FAP–expressing cells. Results In total, 59 ileal and 35 colonic samples were stained and quantified to asses FAP expression (figure 1). A 1.7-fold and 1.9-fold increase of FAP protein expression was seen in inflamed (mean 22.3, p=0.0069); and stenotic (mean 25.5 p=0.0002) CD ileum compared to healthy non-IBD tissue (mean 13.1). Inflamed UC colon (mean 26.8, p = 0.0406) showed a 1.4-fold increase compared to healthy colon (mean 19.2). For the gene expression, 66 ileal and 42 colonic samples were processed and used for qPCR analysis. A 5-fold and 6.4-fold increase of FAP was found in inflamed (mean 0.011, p=0.0475) and stenotic (mean 0.014, p=0.0042) CD ileum, and a 1.7-fold increase was seen in inflamed UC colon (mean 0.278, p=0.0195) compared to controls (means: ileum 0.002; colon 0.165). Conclusion This is the first study reporting the potential of FAP as a fibrotic biomarker not only in stricturing CD, but also in therapy-refractory UC. Significantly increased FAP protein and gene expression is found in inflamed and stenotic ileum in CD and inflamed colon in UC. Additionally, CD90+GP38+ cells have been identified as the most present FAP expressing cells.

OP30 Human umbilical cord mesenchymal stem cells derived exosomes alleviate Ulcerative Colitis by inhibiting macrophage ferroptosis via miR-23b-3p/Nrf2 pathway

Abstract Background Human umbilical cord mesenchymal stem cell derived exosomes (HucMSC-Exo) have broad application prospects in treatment of various disease, including ulcerative colitis (UC). Macrophages can trigger intestinal mucosal inflammation thereby participating in the onset and development of UC. As a newly discovered iron-dependent cell death pathway, ferroptosis has also been found accompanied by inflammatory response in recent studies. We speculated that there could be relationship between macrophage ferroptosis and inflammatory response in UC. Furthermore, the role of macrophage ferroptosis in the process of HucMSC-Exo alleviating UC remains undefined. This study aims to explore the therapeutic effect and mechanism of HucMSC-Exo on UC by regulating macrophage ferroptosis. Methods The gene expression of ferroptosis-related proteins was assessed in colon samples from healthy controls and UC patients to explore the relationship between ferroptosis and UC. In vivo, colitis was induced by dextran sulfate sodium in mice. HucMSC-Exo was administered intravenously to estimate its curative effect, and its gut homing was evaluated by animal live imaging analysis. In vitro, HucMSC-Exo were cocultured with ferroptosis inducer RSL3-treated bone marrow-derived macrophages (BMDMs), RAW264.7 cell line, followed by examining the effect of HucMSC-Exo. Transfection of microRNA mimics and gene knockdown were used to confirm the role of miR-23b-3p in HucMSC-Exo regulating of macrophage ferroptosis. Results Compared with healthy individuals, ferroptosis may be involved in the mucosal inflammation of UC patients. HucMSC-Exo were found to successfully target damaged colon tissues in vivo. HucMSC-Exo treatment significantly improved the pathological damage of colon tissue, increased the expression of glutathione peroxidase 4 (GPX4), while markedly decreasing the levels of iron and lipid ROS, and reducing the secretion of interleukin (IL)-1β and IL-6, and then relieved macrophage ferroptosis to alleviate murine colitis. In vitro experiments showed that HucMSC-Exo could be effectively absorbed by macrophages and rescued RSL3-induced ferroptosis, which was consistent with the effect of ferrostatin-1, a ferroptosis-specifific inhibitor. Mechanismly, HucMSC-exo could inhibit macrophage ferroptosis by delivering its highly expressed miR-23b-3p to activate Nrf2 pathway. Additionally, the protection of HucMSC-exo for UC was attenuated by decreasing the expression of miR-23b-3p or inhibiting Nrf2 pathway. Conclusion HucMSC-Exo could activate Nrf2 antioxidant pathway and abrogate macrophage ferroptosis by delivering miR-23b-3p and ultimately ameliorate colitis.

DOP51 Mucosa-associated microbial signatures associate with objective response prior to the start of anti-TNFα but not vedolizumab or ustekinumab in Crohn’s disease patients

Abstract Background Crohn’s disease (CD) is a complex immune-mediated disease of the gastrointestinal tract where the gut microbiome plays an important role. Current biological treatment options in CD include the anti-TNFα agents adalimumab (ADA) and infliximab (IFX), vedolizumab (VDZ), and ustekinumab (USTE). Finding biomarkers to predict therapy response is still a clinical unmet need, as the majority of CD patients fail to reach endoscopic remission within 1 year of treatment. While the majority of studies focus on fecal samples, mucosa-adherent bacterial signature could bring forth stable biomarkers. In this study, we sought to identify signatures of the adherent microbiome in intestinal biopsies aimed at differentiating responders (R) from non-responders (NR), prior to the start of biological treatment. Methods We prospectively collected paired ileal and colonic biopsies (stored snapfrozen in -80 ºC) from adult CD patients scheduled to start anti-TNFα (IFX and ADA), VDZ and USTE treatment during baseline endoscopies. After 6-12 months of follow-up, patients were classified as either R or NR based on endoscopic response (≥50% reduction in SES-CD score) in combination with steroid-free clinical response (≥3 point drop in HBI or HBI ≤4) and/or biochemical response (≥50% reduction in C-reactive protein (CRP) and fecal calprotectin or a basal CRP ≤5 g/mL and fecal calprotectin ≤250 µg/g). Microbiome composition of the biopsies was determined using 16S RNA gene V3V4 amplicon sequencing. Results For the anti-TNFα cohort, we included in total 36 CD patients (21R and 18 NR), for VDZ cohort a total of 44 patients (28 R and 16 NR) and for USTE cohort a total of 40 patients (20R and 20 NR).When comparing α-diversity and β-diversity between R and NR, we did not find significant differences in ileal and colonic samples at baseline for the VDZ and USTE cohorts. Notable, for the anti-TNFα cohort (table 1), we obtained significant differences when comparing α-diversity (p=0.028) and β-diversity between R and NR. We demonstrated differences between colonic R and NR in taxa abundance for ASVs associated with the phyla Bacteroidetes, Firmicutes, Fusobacteria, Proteobacteria (figure 1). Furthermore, ASVs associated with Firmicutes, Bacteroidetes, Actinobacteria are different in abundance between ileal R and NR (figure 2). Figure 1: Differential taxa abundance colonic R vs NR anti-TNFα Figure 2: Differential taxa abundance ileal R vs NR anti-TNFα Figure 3: graphical summary Conclusion Here, we investigated the microbial signature of R and NR before the start of treatment of three separate cohorts and we demonstrated that the mucosa-associated microbiome differentiates R and NR to anti-TNFα therapy. Further analyses as part of the EPIC Pioneer study, are ongoing.

OP32 The gut virome-colonizing Orthohepadnavirus genus is associated with ulcerative colitis pathogenesis and induces intestinal inflammation in vivo

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory disorder with an unknown etiology1. Over recent years, a growing body of evidence has been pinpointing gut virome dysbiosis as a fundamental component in its progression2, although its role during the early phases of chronic inflammation is far from being fully defined. Therefore, we sought to investigate the role of a virome-associated protein encoded by the Orthohepadnavirus genus, the Hepatitis B virus X protein (HBx)3, during UC aetiopathogenesis. Methods HBx positivity of UC patient-derived blood and gut mucosa was assessed by RT-PCR and Sanger sequencing correlated with clinical characteristics by multivariate analysis. Transcriptomics was performed on HBx-overexpressing endoscopic biopsies from healthy donors. C57BL/6 mice underwent intramucosal injections of liposome-conjugated HBx-encoding plasmids or the control. Multidimensional flow cytometry analysis was performed on colonic samples from HBx-treated and control animals. Transepithelial electrical resistance measurement, proliferation assay, ChIP-Seq, and RNA-Seq were performed on in vitro models of the gut barrier. Results HBx was detected in about 45% of patients with UC (Figure 1) and found to induce colonic inflammation in mice (Figure 2A-2D), while its silencing reverted the colitis phenotype in vivo (Figure 2E-2H). HBx acts as a transcriptional regulator in epithelial cells (Figure 3), provoking barrier leakage and altering inflammatory response (Figures 3 and 4). Conclusion This study paves the way for the understanding of the aetiopathogenesis of UC and provides a brand-new standpoint that looks at the virome as a target for tailored treatments, possibly leading to an entirely new approach to therapeutic intervention.

P036 Analysis of intestinal tissue from newly diagnosed patients with inflammatory bowel disease reveals distinct proteomic profiles

Abstract Background Inflammatory bowel disease (IBD) is a complex multi-factorial disease characterized by chronic inflammation of the gastrointestinal tract. Despite significant efforts to understand the pathogenetic mechanisms of IBD, the elucidation of its etiopathology and progression is far from fully understood. The direct analysis of the intestinal tissue from the endoscopy which leads to IBD diagnosis (before starting any treatment) would be the ideal sample to elucidate IBD pathogenesis. Methods High-throughput mass-spectrometry-based quantitative proteomic analysis was performed using formalin-fixed paraffin-embedded human intestinal samples from newly diagnosed patients to elucidate the potential mechanisms responsible for gut inflammation in Crohn′s disease (CD) and ulcerative colitis (UC). For this purpose, 192 formalin-fixed paraffin-embedded samples from 40 active UC patients, 67 active CD patients and 46 normal biopsies from healthy controls (HC) were analyzed (Figure 1). Proteins with p-value &amp;lt; 0.05 were considered as significantly dysregulated. Moreover, we used Ingenuity Pathway Analysis (IPA) to analyze the pathways and functions in different locations of the gut (ileum or left colon) that could be related to IBD pathogenesis. Results A total of 2,903 proteins were identified, of which 1,010 were differentially expressed between left colon from CD patients and HC. 1,242 proteins were differentially expressed between left colon from UC patients and HC, and 952 differential proteins discriminated between left colon from CD and UC patients. In the comparative study of ileum biopsies from Crohn’s disease patients and healthy controls, 956 proteins were differentially expressed (Figure 2). IPA revealed multiple canonical pathways, including EIF2 signaling, regulation of eIF4 and serine/threonine kinase P7056K signaling, mitochondrial dysfunction, and oxidative phosphorylation altered in ileum biopsies from CD patients compared to HC (Figure 3). Regarding the proteomic study in left colon samples, the main canonical pathways enrichment in the comparison of UC and CD with HC were the following: neutrophil extracellular trap signaling pathways, fatty acid oxidation, sirtuin signaling pathway, tRNA charging, and mitochondrial dysfunction (Figure 4). Conclusion The proteomic results revealed dysregulated proteins and pathways in ileum and left colon biopsies from patients with active CD and UC compared to HC that may unravel key mechanisms contributing to the pathogenesis of these diseases. The results of the study serve as a starting point for hypotheses to understand the pathogenesis and search for therapeutic targets.

P037 Enhancing the efficacy of cannabidiol using protein nanoparticles to treat inflammatory bowel disease

Abstract Background Inflammatory bowel disease (IBD) is a global health burden and approximately 30% of the patients with severe IBD require surgery following treatments, leaving an unmet need of new and safe therapies. Cannabidiol (CBD) is one of the major non-psychoactive and water-insoluble constituents of medicinal cannabis, known for its anti-inflammatory properties in epilepsy. The compound is safe at high doses and doesn’t have the psychotropic effects of delta-9-tetrahydrocannabinol. Therefore, this study investigated the therapeutic potential of CBD in controlling intestinal inflammation. Methods CBD was loaded in the protein nanoparticles (PNP-CBD) and tested for its water solubility. Primary intestinal epithelial cells (IECs; organoids) and bone marrow-derived macrophages (BMDM) were isolated from C57BL/6 mice and treated with IL-1β and LPS, respectively. Stimulated cells were treated with ±CBD and checked for downstream signalling through inflammatory gene expression using qRT PCR. Conditioned media from LPS-treated BMDM was also harvested to treat mIECs to check link between macrophage activation and intestinal inflammation. Accordingly, we assessed the efficacy of CBD in suppressing intestinal inflammation using dextran sulfate sodium (DSS)-induced acute experimental colitis in the C57BL/6J mice. At the end, blood samples were collected for hematology and serum analyses, mesenteric lymph nodes for immune cell signatures, colon samples for histological analysis and qRT PCR analysis for inflammatory genes. Results CBD loading in the protein nanoparticles (PNP-CBD) increased its water solubility up to 60 times. In the mIECs, CBD did not have any effects on cytokine-induced inflammation; however, it significantly dampened LPS-induced BMDM activation and inflammatory cytokine production. The results also showed that inhibition of CB2 but not CB1 receptor can completely abolish the anti-inflammatory potential of CBD in the BMDM. Transferring conditioned media from BMDM to mIECs showed macrophage-specific targeting alleviated inflammation in the mIECs. These have also been observed in the acute DSS colitis model where not CBD alone but PNP-CBD improved disease severity index including body weight loss, diarrhoea, shorter colon length, and inflammatory gene expression in the colon. PNP-CBD also reduced histological colitis and increased goblet cell mucin production in the DSS-treated colon. Conclusion Encapsulation of CBD increased water solubility and efficacy in alleviating intestinal inflammation in ulcerative colitis. These data also demonstrated that CB2 receptor targeting of macrophage activation is the primary mechanism of CBD’s effect.

P043 ALI culture derived from human organoids recapitulates cell composition during intestinal crypt formation

Abstract Background The ALI (air liquid-interface) culture derived from human primary intestinal epithelium is generating considerable interest for closely reproducing the mature cell features of the differentiated epithelium in a 2D configuration. However, the phenotypic changes occurring in the human ALI culture during cell differentiation have thus far not been explored in depth. Here, we aimed to characterize the cell composition of human ALI culture over time. Methods 3D epithelial organoids (n=3) were expanded from human colonic samples and organoid-derived single cells were seeded on a Transwell. After reaching confluence, the submerged 2D was switched to ALI and maintained for 7 days. The ALI culture was analysed every 24h by qPCR, membrane staining (H&amp;E and immunofluorescence) and trans-epithelial resistance (TER) (Figure 1). Results The confluent pre-ALI (TER&amp;gt;200 Ω*cm2) showed high mRNA expression of stem cell markers (i.e., LGR5, AXIN2), while several differentiation markers (i.e., ZG16, CLCA1, ANPEP, AQP8, BEST4, CHGA) were almost undetectable, thus resembling the stem cell niche compartment. Air exposure of the 2D culture induced an early and transient (limited to ALI-day 1) transcriptional up-regulation of proliferation markers (i.e., MKI67, CDCA7) and OLFM4, followed by a concomitant marked downregulation of stem cell markers, thus mimicking the Transit Amplifying compartment. OLFM4 protein, as observed by immunofluorescence, showed an early cytoplasmic accumulation followed by secretion at later time points (from ALI-day 5). Differentiation towards absorptive and secretory lineages increased gradually from ALI-day 5 and ALI-day 7 onward, respectively, at both the transcriptional and protein level. Expression changes were accompanied by the progressive transition of the ALI monolayer from a squamous to a columnar morphology. In parallel, TER promptly increased upon ALI switch, thus indicating the early establishment of cell-cell junctions. Conclusion By recapitulating the cell composition identified along the crypt, the ALI culture holds promise to be a versatile in vitro model for studying how the different epithelial cell compartments respond to specific environmental stimuli, like those present during an inflammatory flare.

A NOVEL DRUG THERAPY INDUCES MITOCHONDRIAL BIOGENESIS AND ATTENUATES COLITIS

Abstract Mitochondrial dysfunction is a characteristic feature of intestinal epithelium cells (IEC) in IBD patients, associated with oxidative stress and impaired ATP production. We posit that disrupted mitochondrial bioenergetics impairs ulcer healing in IBD. In the current study, we tested a novel gold-based compound (AuPhos) that improves mitochondrial function by increasing mitochondrial biogenesis and antioxidant enzymes in IEC and human colonic biopsies. METHODS: Normal human colonic epithelial cells (NCM460) were used to evaluate the effect of AuPhos on mitochondrial proteins and anti-oxidant proteins by western blotting in the presence or absence of low-dose TNF (1ng/ml). To model mitochondrial deficiency, TFAM (mitochondrial transcriptional factor A) was silenced (shTFAM) in NCM460 cells. These cells were treated with low-dose TNF to mimic inflammatory conditions in the human intestine. The mitochondrial mass was assessed by flow cytometry using mito tracker green. The transcriptional activity of genes associated with mitochondrial biogenesis, mitochondrial complexes, and anti-oxidants was evaluated using RT-qPCR in AuPhos or vehicle-treated (overnight) cells with or without TNF. Human colonic biopsy samples were collected in Allprotect, treated ex-vivo with vehicle or AuPhos (3h, 4oC), and processed for RNA isolation followed by RT-qPCR. RESULTS: Biochemical and mass spectrometry analyses revealed that AuPhos localizes to the mitochondria. We show here that AuPhos increases mitochondrial mass and mRNA for mitochondrial complexes [complex IV (Cox6A1) and complex V (ATP5A1)] in NCM460 cells in TNF or vehicle-treated cells. Similarly, AuPhos increased protein levels of upstream regulators of mitochondrial biogenesis such as TFAM, PGC-1α, and Nrf2 compared to nontreated cells. Further protein analysis of AuPhos-treated cells showed that AuPhos increases downstream antioxidant markers such as manganese superoxide dismutase (MnSOD), peroxidane 3 (Prd3), glutathione peroxidase 4 (GPX4), thioredoxin reductase2 (Trx2), and catalase expression when compared to the TNF or control samples. Interestingly, expression of genes associated with mitochondria-specific (MnSOD) and cytoplasmic superoxide dismutase (CuZnSOD) were also significantly increased in AuPhos-treated shTFAM NCM cells compared to vehicle or TNF-treated cells. AuPhos substantially upregulates the expression of mtCO1, mtCO2, Cox6A1, ATP5A1, NRF1, MnSOD, GPX, PRDX-2,-4, and -6, in ex vivo treated human colonic biopsies compared to vehicle or TNF-treated samples. CONCLUSIONS: The current data suggest that the AuPhos compound improves mitochondrial function by promoting the expression of mitochondrial-associated proteins and antioxidant enzymes (Figure 1). We believe AuPhos can be used as a potential therapeutic in treating ulcerative colitis and Crohn’s disease by restoring mitochondrial biogenesis.

AUPHOS, A NOVEL DRUG THAT IMPROVES COLITIS BY MICROBIOME INDUCED METABOLIC CHANGES

Abstract BACKGROUND Dysbiotic intestinal microbiomes dominated by facultative anaerobes are strongly associated with inflammatory bowel disease (IBD). More recently, data from Baumler and colleagues support a model where mitochondrial dysfunction causes disease-associated dysbiosis by increasing oxygen (O2) availability to the microbiome. We posit that the restoration of epithelial mitochondrial respiration contributes to the restoration of a healthy microbiome dominated by facultative anaerobes such as Firmicutes [that produce short chain fatty acids (SCFA)]. Here, we tested a novel compound (AuPhos) that increases an O2 consumption in intestinal epithelial cells (IECs) thereby reducing O2 availability to the microbiome and promotes a healthy anaerobic environment (and blooms of firmicutes). METHOD Inbred C57BL/6 mice (n=3) were given oral vehicle (0.5% DMSO/Tween-80) or AuPhos (2.5 or 25mg/Kg;q3d) for two weeks, and colon and stool samples were extracted at day-15 sacrifice. Microbial DNA was isolated from stool samples using PoweFecal kit followed by 16S rRNA metagenomic sequencing. Linear Discriminant Analysis (LDA) and PICRUST2 were performed to reveal differentially abundant bacterial species and functional potentials of bacterial communities, respectively. Similar microbial profiling was performed on AuPhos-fed acute colitis mice (2% DSS-7d; Recovery-16d). Effect of AuPhos on microbial metabolism was determined by 1H NMR for detecting SCFA synthesis by gut microbiota in stool samples (n=3) collected after 3 consecutive doses. AuPhos-induced hypoxia in IECs was assessed by Hypoxyprobe-1 kit. RESULT Metagenomic analysis showed reduction in relative abundance of (O2 consuming) Proteobacteria and facultatively anaerobic Enterobacteriaceae in the gut, in AuPhos-fed mice. Conversely, AuPhos treatment dose- dependently increased the relative abundance of signature anaerobic bacteria e.g. Firmicutes including Clostridia (Faecalibacterium prausnitzii, Roseburia sp.), Bifidobacterium, etc. PICRUST2 and LDA revealed that AuPhos decreased bacterial LPS biosynthetic pathway and increased overall fatty acid biosynthesis pathways. AuPhos increased butyrate and propionate levels by &amp;gt;35% and acetate by 60% (n=3) compared to stools from vehicle-treated mice. In DSS-colitis mice, AuPhos reduced the relative abundance of inflammatory Proteobacteria, which includes facultative anaerobic Enterobacteriaceae family and increased Firmicutes over time (p&amp;lt;0.05). Interestingly, hypoxia staining showed AuPhos-induced O2 utilization in colonic surface IECs, facilitating obligate anaerobe-promoting environment in the gut. CONCLUSION These finding suggest that AuPhos is a “first-in-class” oral therapeutic that has a potential to correct microbial dysbiosis in IBD by reducing epithelial oxygenation and thereby promoting a healthy microbiome dominated by obligate anaerobes.

Selection and Evaluation of mRNA and miRNA Reference Genes for Expression Studies (qPCR) in Archived Formalin-Fixed and Paraffin-Embedded (FFPE) Colon Samples of DSS-Induced Colitis Mouse Model.

The choice of appropriate reference genes is essential for correctly interpreting qPCR data and results. However, the majority of animal studies use a single reference gene without any prior evaluation. Therefore, many qPCR results from rodent studies can be misleading, affecting not only reproducibility but also translatability. In this study, the expression stability of reference genes for mRNA and miRNA in archived FFPE samples of 117 C57BL/6JOlaHsd mice (males and females) from 9 colitis experiments (dextran sulfate sodium; DSS) were evaluated and their expression analysis was performed. In addition, we investigated whether normalization reduced/neutralized the influence of inter/intra-experimental factors which we systematically included in the study. Two statistical algorithms (NormFinder and Bestkeeper) were used to determine the stability of reference genes. Multivariate analysis was made to evaluate the influence of normalization with different reference genes on target gene expression in regard to inter/intra-experimental factors. Results show that archived FFPE samples are a reliable source of RNA and imply that the FFPE procedure does not change the ranking of stability of reference genes obtained in fresh tissues. Multivariate analysis showed that the histological picture is an important factor affecting the expression levels of target genes.

Bacterial species-specific antimicrobial efficacies of three different body embalming solutions for anatomical studies.

While body decompensation is mainly facilitated by bacteria, investigating the antimicrobial properties of body preservation methods is still a neglected research area. We performed microbiological sampling for potentially pathogenic bacteria species of brain, lung, liver, colon, and subcutis samples obtained from bodies perfused with embalming solutions of variable composition with emphasis on variable formaldehyde concentrations. We, thereby, identified spore-forming aerobic and anaerobic bacteria mainly in the samples obtained from the colon of ethanol- and lower-concentrated formaldehyde formulation embalmed bodies. Moreover, we could identify Enterococcus species in bodies preserved with the latter method. Tissue samples of the subcutis remained sterile. Long-term incubation of special mycobacteria growth indicator tubes revealed no growth of mycobacteria in all 60 samples analyzed. Overall, we show survival of bacterial genera known to be especially environmentally resistant but also include potentially pathogenic members. Knowledge of bactericidal capacities of embalming solutions are therefore critical to assess risk and apply appropriate disinfection routines while working with human bodies. Moreover, new formulations to reduce potentially toxic substances for embalming needs to be evaluated regarding their bactericidal capacities.

Microbiome and Metabolome Variation as Indicator of Social Stress in Female Prairie Voles.

Social isolation is detrimental to the health of social mammals inducing neurochemical and hormonal changes related to depression and anxiety, as well as impairments of cardiovascular and immune functioning. Likewise, perceptions of loneliness are increasingly recognized as detrimental to human psychological well-being, cognitive functioning, and physical health. Few studies, however, have examined the impact of social isolation on the intestinal microbiome and metabolome. To better understand the impact of social isolation on these systems, intestinal microbiota, and the systemic impact via the gut-brain axis, we employed prairie voles. Physiological stress on female prairie voles (n = 22) either with a same-sex sibling (n = 11) or in isolation (n = 11) for four weeks demonstrated behavioral indicators of increased anxiety and depression in isolated voles (p ≤ 0.01). Bacterial DNA from fecal and colon samples, collected at five time points (T0-4), were sequenced for all nine hypervariable regions of the 16S rRNA gene. Microbiome analyses revealed several differences in gut communities of paired and isolated voles with greater differences at T4. Notably, several taxa associated with host health including Anaerostipes and Lactobacillaceae were more prevalent in paired voles, whereas several taxa associated with known pathogens (e.g., Staphylococcaceae and Enterococcus) or disease were elevated in isolated animals. Similarly, metabolome analyses suggested isolated voles, when compared to paired animals, exhibited differences in metabolites associated with diabetes and colitis. These findings further contribute to our understanding of the harmful effects of social isolation, which cause perturbations in the gut microbiome and serum metabolites.

The Importance of Endoscopy with Biopsy: Real-World Evidence of Gastrointestinal Involvement in Primary Immunodeficiency in Two Main Northern Italian Centres.

Inborn errors of immunity (IEI) represent a heterogeneous group of diseases in which the true prevalence of GI involvement is not well-known. This study evaluates the prevalence of lower GI manifestations in patients with common variable immunodeficiency (CVID), analysing the histologic findings in colonic samples and assessing any correlations with biochemical abnormalities. A retrospective study was performed by collecting the data of IEI adult patients followed up at two main Northern Italian centres. Demographic and clinical data, and blood tests were collected. A colonoscopy with multiple biopsies in standard sites, in addition to a biopsy for any macroscopic lesion, was performed. The gastrointestinal Symptom Rating Scale for Irritable Bowel Syndrome (GSRS-IBS) and the short Inflammatory Bowel Disease Questionnaire (sIBDQ) were used to assess GI symptoms. 141 patients were included: 121 (86.5%) with CVID, 17 (12.1%) with IgG subclass deficiency, and 2 (1.4%) with X-linked agammaglobulinemia. Of the patients, 72 (51%) complained of GI symptoms. No differences were seen between patients receiving or not IgRT. GI infections were found in 9 patients (6.4%). No significant correlations were found between gut infections and symptoms or leukocyte infiltrates. Colonoscopy alterations were present in 79 patients (56%), and the most common were colon polyps (42%). Microscopical abnormalities were seen in 60 histologic samples (42.5%) and the most frequent was nodular lymphoid hyperplasia (40%). A leukocyte infiltrate was present in 67 samples (47.5%), and the most common was a lymphocyte infiltrate (33%). No correlation was found between GI symptoms and macroscopic alterations, whereas a positive correlation between symptoms and microscopic alterations was detected. GI symptoms and microscopic alterations in colon samples are closely related; hence, it is important to carry out serial colonic biopsies in every CVID patient, even in the absence of macroscopic lesions.

Acute infection with Brachyspira hyodysenteriae affects mucin expression, glycosylation, and fecal MUC5AC.

Infection with strongly β-hemolytic strains of Brachyspira hyodysenteriae leads to swine dysentery (SD), a production-limiting disease that causes mucohemorrhagic diarrhea and typhlocolitis in pigs. This pathogen has strong chemotactic activity toward mucin, and infected pigs often have a disorganized mucus layer and marked de novo expression of MUC5AC, which is not constitutively expressed in the colon. It has been shown that fucose is chemoattractant for B. hyodysenteriae, and a highly fermentable fiber diet can mitigate and delay the onset of SD. We used lectins targeting sialic acids in α-2,6 or α-2,3 linkages, N-acetylglucosamine (GlcNAc), α-linked L-fucose, and an immunohistochemical stain targeting N-glycolylneuraminic acid (NeuGc) to investigate the local expression of these mucin glycans in colonic tissues of pigs with acute SD. We used a commercial enzyme-linked immunosorbent assay (ELISA) to quantify fecal MUC5AC in infected pigs and assess its potential as a diagnostic monitoring tool and RNA in situ hybridization to detect IL-17A in the colonic mucosa. Colonic mucin glycosylation during SD has an overall increase in fucose, a spatially different distribution of GlcNAc with more expression within the crypt lumens of the upper colonic mucosa, and decreased expression or a decreased trend of sialic acids in α-2,6 or α-2,3 linkages, and NeuGc compared to the controls. The degree of increased fucosylation was less in the colonic mucosa of pigs with SD and fed the highly fermentable fiber diet. There was a significant increase in MUC5AC in fecal and colonic samples of pigs with SD at the endpoint compared to the controls, but the predictive value for disease progression was limited. Fucosylation and the impact of dietary fiber may play important roles in the pathogenesis of SD. The lack of predictive value for fecal MUC5AC quantification by ELISA is possibly due to the presence of other non-colonic sources of MUC5AC in the feces. The moderate correlation between IL-17A, neutrophils and MUC5AC confirms its immunoregulatory and mucin stimulatory role. Our study characterizes local alteration of mucin glycosylation in the colonic mucosa of pigs with SD after B. hyodysenteriae infection and may provide insight into host-pathogen interaction.

Purification methods to reduce interference by dextran sodium sulfate with quantification of gene expression in intestinal tissue samples from a piglet model of colitis.

Dextran sodium sulfate (DSS) is commonly used to induce intestinal (i.e., colonic) inflammation in a variety of animal models. However, DSS is known to cause interference when using quantitative-real time polymerase chain reaction (qRT-PCR) methods, thereby invalidating accurate and precise measurement of tissue gene expression. Therefore, the goal of this study was to determine whether different mRNA purification methods would reduce DSS-interference. Colonic tissue samples were collected at postnatal days (PND) 27 or 28 from pigs that had not been administered DSS (Control), and two independent groups of pigs that received 1.25 g of DSS/kg of BW/d (DSS-1 and DSS-2) from PND 14 to 18. Tissue samples collected were subsequently stratified into three purification methods (i.e., 9 total treatment × method combinations), including: 1) no purification, 2) purification with lithium chloride (LiCl), or 3) purification using spin column filtration. All data were analyzed using a one-way ANOVA in the Mixed procedure of SAS. The average RNA concentrations across all treatments were between 1,300 and 1,800 μg/μL for all three in vivo groups. Although there were statistical differences among purification methods, the 260/280 and 260/230 ratios fell between acceptable limits of 2.0 to 2.1 and 2.0 to 2.2, respectively, for all treatment groups. This confirms the RNA quality was adequate and not influenced by purification method in addition to suggesting the absence of phenol, salts, and carbohydrate contamination. For pigs in the Control group that did not receive DSS, qRT-PCR Ct values of four cytokines were achieved, though these values were not altered by purification method. For pigs that had undergone DSS dosing, those tissues subjected to either no purification or purification using LiCl did not generate applicable Ct values. However, when tissues derive from DSS-treated pigs underwent spin column purification, half of the samples from DSS-1 and DSS-2 groups generated appropriate Ct estimates. Therefore, spin column purification appeared to be more effective than LiCl purification, but no method was 100% effective, so caution should be exercised when interpreting gene expression results from studies where animals are exposed to DSS-induced colitis.