bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reprogramming T-cell metabolism to enhance adoptive cell therapies
Authors: Kates Meghan , Saibil Samuel D 
Published: February 2024

Abstract
Adoptive cell therapy (ACT) is an immunotherapeutic approach that involves isolating T cells from a patient, culturing them ex vivo, then reinfusing the cells back into the patient. Although this strategy has shown remarkable efficacy in hematological malignancies, the solid-tumour microenvironment (TME) has presented serious challenges for therapy efficacy. Particularly, the TME has immunosuppressive signalling and presents a metabolically challenging environment that leads to T-cell suppression. T-cell metabolism is an expanding field of research with a focus on understanding its inherent link to T-cell function. Here, we review the current model of T-cell metabolism from naïve cells through effector and memory life stages, as well as updates to the model from recent literature. These models of metabolism have provided us with the tools and understanding to explore T-cell metabolic and mitochondrial insufficiency in the TME. We discuss manipulations that can be made to these mitochondrial and metabolic pathways to enhance the persistence of infused T cells, overcome the metabolically challenging TME and improve the efficacy of therapy in ACT models. Further understanding and investigation of the impact of metabolic pathways on T-cell performance could contribute to improving therapy efficacy for patients.
A1 PRE-CLINICAL CROHN’S DISEASE MICROBIOME PROMOTES INFLAMMATION IN GNOTOBIOTIC RECIPIENT MICE
Authors: Dang C , Chen-Liaw A , Luchak A , Sandhu I , Mu K , Xue M , Lee S , Mogno I , Streutker C , Britton G J , Faith J J , Turpin W , Croitoru K 
Published: February 2024

Abstract

Background
Crohn’s disease (CD) is a chronic disorder of unknow etiology. We recently demonstrated that microbiome composition is associated with the risk of CD development; however, its potential causal effect remains unknown.

Aims
Given the fact that first-degree relatives (FDRs) that are sibling likely to share similar environmental and genetic makeup, we selected pairs of discordant siblings (one remaining healthy referred to as healthy matched control-HMC, and the other who developed CD later on referred to as pre-CD) to investigate whether the microbiome contributes to or triggers dysregulated immune response by transplanting microbiome from them into germ-free mice (GFM).

Methods
Faecal samples from discordant siblings, recruited as part of the CCC-GEM project, a cohort of prospectively followed healthy first-degree relatives, were transplanted into RAG1-/- GFM before T-cell transfer-induced colitis. Fecal Lipocalin-2 (LCN-2) was measured by ELISA to assess gut inflammation. Body weight was monitored for 6 weeks after T-cell transfer. Intestinal tissue damage was assessed by histology scoring (PMID: 8623920). Pro-inflammatory cytokine gene profile of ileum and colon tissue was measured by qPCR. R-software was used for statistical analysis.

Results
Our results showed that mouse recipients of pre-CD microbiota experienced more weight loss than HMC group, with a greater difference observed in the second week after inducing colitis (p=0.0019). LCN-2 of pre-CD mice was significantly higher after T-cell transfer for 3 weeks. Intriguingly, pre-CD stool recipient mice had higher histological damage score in the ileum (p=0.025). Histological analysis revealed that granulomatous inflammation, mucin depletion, crypt loss were greater in pre-CD group (p≤0.05). Pre-CD stool promoted the expression of selected pro-inflammatory cytokine genes in the ileum with significant increases of TNFα, IL-1β, IFNγ, IL10 and TGFβ compared to mice that received HMC microbiome. Colonic tissue showed significant increases in TNFα and TGFβ in the mice recipient of the pre-CD microbiome.

Conclusions
These results suggests that pre-CD microbiome can worsen T cell transfer colitis in mice compared to HMC microbiome. This suggests that microbiome or other constituents of stool from pre-CD subjects are major contributors to the onset of disease. Modulating pre-CD microbiome composition could lead to novel methods to prevent CD onset.

Funding Agencies
CCC, CIHRWeston Family Foundation, Helmsley, Biocodex
A3 INVESTIGATING MACROPHAGE-TISSUE CELL COMMUNICATION AXES IN THE GASTROINTESTINAL TRACT
Authors: Ngai L , Mortha A 
Published: February 2024

Abstract

Background
The gastrointestinal tract boasts the highest concentration of macrophages (MPs) in the body, acting as vital immune sentinels that oversee tissue balance. Three distinct subsets of MPs, namely CCR2+, Tim4+, and CCR2,Tim4 double-negative (DN) MPs, populate distinct gut niches. Their functional specialization suggests unique interactions within their non-hematopoietic tissue microenvironments. Despite their crucial roles, the intricacies of these interactions remain elusive. One recently discovered interaction involves a communication axis between MPs and neurons within the muscularis layer of the gut. Here, neurons secrete Colony Stimulating Factor 1 (CSF1), a survival factor for MPs. These MPs reciprocate by producing Bone Morphogenetic Protein 2 (BMP2), assisting neurons in regulating gut motility.

Aims
Based on the aforementioned interaction, we hypothesize that BMP2, derived from tissue-resident MPs, might influence functions of other tissue niches, subsequently prompting survival of MP via CSF1 production. Our aims are twofold: (1) Identify the role of BMP2 in gut macrophages; (2) Identify BMP2-responsive CSF1-producing tissue cells within the gut.

Methods
To discern the roles of MP subsets, we developed a conditional knockout mouse model, targeting Bmp2 expression in MPs. We validated successful Bmp2 deletion(BMP2 KO) through quantitative polymerase chain reaction (qPCR) and an in-situ hybridization immunofluorescence assay (RNAscope). Subsequently, single cell RNA (scRNAseq) was performed, combining samples from both control and KO small intestines. This was done to further confirm BMP2 KO and to identify BMP2-responsive CSF1-producing cells. Flow cytometry was then used to characterize the intestinal MPs in control and KO mice.

Results
Tim4+ MPs emerged as the primary source of BMP2. Comprehensive analysis using qPCR, RNAscope, and scRNAseq validated the complete KO of BMP2 across all macrophage subsets. The loss of MP-produced BMP2 led to a disruption in MP development. Notably, a marked reduction in DN and Tim4+ MPs was observed following deletion of Bmp2 in MPs, emphasizing the critical role of BMP2-driven CSF1 in sustaining these subsets. CSF1 producing cells co-expressing the cognate BMP receptor in the gut, were predominantly non-hematopoietic tissue cells. Among these, distinct fibroblast populations emerged as a potent but not the sole source of CSF1.

Conclusions
Our work underscores the involvement of multiple tissue cell populations, revealing an intricate network of interactions that extends beyond fibroblasts. This study unveils the multifaceted nature of tissue-MP interactions and their critical roles in maintaining gut homeostasis. Disturbances of these pathways may pave the way for disease by altering tissue homeostasis.

Funding Agencies
NSERC
A6 LYSOPHOSPHATIDYLCHOLINE (LPC) AND LYSOPHOSPHATIDIC ACID (LPA) INDUCE VISCERAL HYPERSENSITIVITY IN IRRITABLE BOWEL SYNDROME (IBS)
Authors: Pujo J , De Palma G , Lu J , Rueda G H , Hall-Bruce M , Nardelli A , Vicentini F A , Verdu E , Vanner S , Collins S , Bercik P 
Published: February 2024

Abstract

Background
Chronic abdominal pain is the key symptom in IBS. Gut microbiota produces a large variety of molecules that can regulate pain perception, including bioactive lipids. LPC and LPA are phospholipids, known to generate and maintain neurogenic pain in mammals, by directly activating multiple channels and G-protein coupled receptors on sensory neurons. LPC and LPA result from the conversion of phosphatidylcholine (PC), a major membrane-forming phospholipid in eucaryotes, as byproducts of inflammation. PC is also present in high concentration in eggs, meat and soybeans. It is unknown whether these two phospholipids play any role in chronic abdominal pain and whether they can be produced by the gut microbiota.

Aims
To investigate whether 1) LPC and LPA are increased in stool of IBS patients, and 2) whether microbiota from IBS patients can produce LPC and LPA and lead to visceral hypersensitivity.

Methods
Stool samples from 27 patients with IBS, collected both during periods of severe and minimal/no pain, were assessed for LPC and LPA levels by ELISA. Germ-free (GF) NIH Swiss and Swiss Webster mice (n=101) both sexes were colonized with fecal microbiota from IBS patients with either high or low fecal LPC and LPA levels, or microbiota from healthy controls. Mice were fed with control diet or diet enriched with PC diet (2g/kg of diet) for 5 weeks. Their visceral sensitivity was then assessed by measuring visceromotor responses to colorectal distension. The fecal samples were collected to measure the production of LPC and LPA

Results
The fecal concentrations of LPC and LPA were higher in IBS patients when experiencing severe abdominal pain, compared to periods of minimal or no pain. Mice colonized with fecal microbiota from IBS patients with high fecal LPC and/or LPA displayed visceral hypersensitivity compared to mice colonized with microbiota from healthy controls, or microbiota from patients with low fecal LPC and/or LPA levels. However, this increase in visceral sensitivity was only found in mice fed with diet enriched with PC. Furthermore, the increased pain responses to colorectal distension correlated with higher concentrations of fecal LPC and LPA.

Conclusions
Our data suggest that bacterial LPC and LPA is responsible for chronic abdominal pain in a subset of patients with IBS. Further studies are needed to identify the specific bacterial strains that produce these nociceptive phospholipids and precise mechanisms by which LPC and LPA induce visceral hypersensitivity.

Funding Agencies
CIHRThe W.Garfield Weston Foundation
A9 LOSS OF INTESTINAL EPITHELIAL NCOR1 INCREASES OXIDATIVE METABOLISM
Authors: Lecours M , Di Castro A , Herrera Pulido J , Gendreau M , Jones C , Perreault N , Boudreau F 
Published: February 2024

Abstract

Background
The nuclear co-repressor NCOR1 acts as a central platform of a complex that represses gene expression associated with inflammatory response. Literature also recently uncovered its possible role in oxidative metabolism in some tissues and organs. Although intestinal epithelial NCOR1 is crucial to restrict IBD symptoms during experimental colitis, its precise role in controlling intestinal epithelial cell biology has not been established.

Aims
We aimed to investigate the role of intestinal epithelial NCOR1 in oxidative metabolism.

Methods
Crossing Villin-Cre and Ncor1loxP/loxP mice was performed to delete Ncor1 in the whole intestinal epithelium conditionally. Crypts from control and NCOR1ΔIEC littermates were isolated to generate colonoids 3D cultures. Phenotypic, genotypic, and transcriptomic analyses were performed on those colonoids.

Results
Colonoids from NCOR1ΔIEC mice were phenotypically smaller but were found to display drastic higher intestinal stem cell propagation features during organoid clonogenic assays. A Gene Set Enrichment Analysis from RNA sequencing predicted an increase in oxidative metabolism in NCOR1ΔIEC colonoids. Several genes associated with oxidative metabolism were confirmed to be modulated in both NCOR1ΔIEC colonoids and the colon of NCOR1ΔIEC mice. Mitochondrial mass was also significantly increased in colonoids when NCOR1 was absent. Loss of the co-repressor did not affect the expression of PGC1-α, a known antagonist of NCOR1. However, transcripts of cytochrome c somatic (Cycs), a target gene of PGC1-α, were found higher in NCOR1ΔIEC colonoids, suggesting that the coactivator activity is increased in the absence of NCOR1.

Conclusions
Our results highlight a new role for NCOR1 in the oxidative metabolism of intestinal epithelial cells. Its action via PGC1-α activity could potentially be targeted as a therapeutic measure during inflammatory bowel diseases.

Funding Agencies
CIHR
A12 ROLE OF INTESTINAL EPITHELIAL HNF4A IN PROTECTING AGAINST ACUTE INFLAMMATORY STIMULI
Authors: Pupo Gómez D , Reyes Nicolas V , Marrero Cofino G , Perreault N , Menendez A , Boudreau F 
Published: February 2024

Abstract

Background
Inflammatory bowel disease is a group of chronic resulting from complex interactions between host susceptibility genes, the host microbiome, the immune system, and environmental triggers. The gastrointestinal epithelium acts as a barrier against harmful stimuli, and defects in its integrity are a precursor for the development of IBD. Our laboratory has shown that the conditional deletion of Hnf4a in the mouse intestinal epithelium leads to chronic intestinal inflammation. However, the functional role of HNF4A on epithelial barrier integrity is still controversial.

Aims
To evaluate the impact of Hnf4a deletion on barrier integrity during acute inflammation.

Methods
We used a tamoxifen-inducible CreER-loxP system to delete Hnf4a in the adult intestinal epithelium (Hnf4aΔIEC-ind). Intestinal permeability was assessed in Hnf4aΔIEC-ind and control mice in the collected serum after oral gavage of FITC-dextran. Mice were infected with an invasion-attenuated strain of Salmonella Typhimurium (SB103). S. Typhimurium loads were scored in the feces, liver, and spleen tissue. Histological analysis was carried out by various staining. Also, we used a model of T-cell-induced enteropathy triggered by a T-cell activating monoclonal anti-CD3ε Ab (145-2C11). Mice were assessed for clinical signs of enteropathy and sacrificed 1-, 3-, and 5 days post-injection. Gene expression of selected targets was studied by RT-qPCR.

Results
FITC-dextran assay showed a significant increase of the intestinal permeability in uninfected mutant mice compared to controls. In contrast, an oral infection with an invasion-deficient S. Typhimurium strain did not differentially impact in tissue bacterial loads or epithelial damage between groups. Likewise, the loss of epithelial HNF4A led to increased Muc2 transcripts expression in the ileum of infected mutant mice but not in the colon. Histological examinations at four days post-infection showed an elevated number and size of goblet cells in the ileal crypts of mutant mice. Bacterial localization using the general bacterial probe EUB388-cy3 (red) staining showed that infected mutant mice tended to enhance barrier mucus layer thickness compared to the controls. On the contrary, acute T cell activation with anti-CD3 mAb induced a significant increase of mRNA expression of Cxcl1 in the small intestine of mutant mice. H&E staining showed elongated ileal crypts in mutant mice compared to controls after anti-CD3 injection.

Conclusions
Altogether, these results support that HNF4A could play a crucial adaptive role in modulating the small intestine epithelial barrier function and controlling the immune system during acute inflammatory stress.

Funding Agencies
CCC, CIHR
A13 MICROBIOTA FROM PATIENTS WITH INFLAMMATORY BOWEL DISEASE (IBD) INDUCE ALTERED BEHAVIOUR AND VISCERAL HYPERSENSITIVITY IN MICROBIOTA-HUMANIZED MICE
Authors: Vicentini F A , Pujo J , Rueda G H , Nardelli A , De Palma G , Verdu E , Collins S , Bercik P 
Published: February 2024

Abstract

Background
IBD is characterized by relapsing episodes of tissue-damaging inflammation in the gastrointestinal tract. Abdominal pain is common in IBD and often persists in the absence of overt inflammation. The treatment has limited efficacy, in part due to our partial understanding of its pathophysiology, and thus commonly leads to dependency on opioids. Moreover, patients with IBD are more likely to develop psychiatric comorbidities (anxiety and depression), further impairing the disease course and quality of life. The gut microbiota has been shown to modulate pain, mood, and anxiety. Gut bacterial composition and function are altered in patients with IBD. However, whether IBD microbiota affects pain perception and emotional behaviour is unknown.

Aims
To determine whether microbiota from patients with IBD contributes to visceral hypersensitivity and behavioural abnormalities in a microbiota-humanized mouse model.

Methods
Adult germ-free C57BL/6 mice (n=65) of both sexes were colonized with fecal microbiota from 7 patients with IBD (Crohn’s Disease n=5, Ulcerative Colitis n=2) and 3 healthy controls (HC). Mice were fed with a human-like (Western) diet. Behavioural tests (light preference, open field, and tail suspension tests) were employed to assess anxiety- and depression-like behaviour. Visceral sensitivity was assessed by measuring visceromotor responses to colorectal distension.

Results
Compared to mice with HC microbiota, mice with IBD microbiota had reduced body weight gain. However, no differences in colon length were found, suggesting that IBD microbiota did not induce overt colonic inflammation. Mice with IBD microbiota displayed a reduced preference for the light chamber and increased immobility in the tail suspension test compared to HC mice, suggestive of anxiety- and depression-like behaviour, respectively. Importantly, no differences in overall locomotion were observed, thus ruling out sickness-like behaviour. When subjected to colorectal distension, mice with IBD microbiota had an overall higher visceromotor response (area under the curve) compared to HC mice. Furthermore, they displayed increased responses to non-noxious stimuli (100 μL distension), suggestive of visceral allodynia.

Conclusions
Our data demonstrate that microbiota from patients with IBD negatively affects the gut-brain axis, by inducing changes in emotionality-related behaviour and triggering visceral hypersensitivity. Uncovering the microbial products and molecular mechanisms underlying these abnormalities will guide the development of novel microbiota-based therapies for patients with IBD.

Funding Agencies
CCC, CIHRCrohn's and Colitis Foundation (USA)
A17 COMPARING ENDOSCOPIST DIAGNOSIS OF COLORECTAL POLYPS ASSISTED BY ARTIFICIAL INTELLIGENCE (CADX) VS CADX WITHOUT ENDOSCOPIST INPUT: A RANDOMIZED CONTROLLED TRIAL
Authors: Djinbachian R , Haumesser C , Taghiakbari M , Alj A , Barkun A , Liu J , Panzini B , Sidani S , von Renteln D 
Published: February 2024

Abstract

Background
Artificial intelligence-based optical diagnosis systems (CADx) have been developped to assist in eliminating the need for histologic diagnosis of diminutive colorectal polyps (resect-and-discard and diagnose-and-leave strategies). However, these systems have not yet been implemented in routine clinical practice.

Aims
We were interested in evaluating the performance of CADx without human input to diagnoses performed by endoscopists assisted by CADx.

Methods
We performed a randomized clinical trial of patients undergoing elective colonoscopies at the CHUM. Patients were randomized into two arms: 1) optical diagnosis of colorectal polyps using CADx without human input; 2) endoscopists performed optical diagnosis after consulting a real-time CADx diagnosis (Human in the Loop [HiL]). Primary outcome was accuracy in optical diagnosis for both arms.

Results
467 patients were randomized (229 in the CADx group, 238 in the HiL group). Overall accuracy for optical diagnosis was 76.3% in the CADx group and 70.5% in the HiL group (p=0.19). Sensitivity, specificity, PPV and NPV for adenoma diagnosis were 89.7%, 58.4%, 82.2%, and 72.5% respectively in the CADx group vs 85.3%, 69.6%, 81.8%, and 74.8% in the HiL group. Sensitivity, specificity, PPV and NPV did not differ significantly between the two groups.

Conclusions
Optical diagnosis of colorectal polyps had similar accuracy when using CADx without human input compared to endoscopist-based diagnosis assisted by CADx. Resect and discard and diagnose and leave strategies can therefore potentially be implemented without need for endoscopist optical diagnosis.

Funding Agencies
CAGFujifilm
A21 EFFECTS OF LYOPHILIZED FECAL FILTRATE COMPARED TO LYOPHILIZED DONOR STOOL IN THE TREATMENT OF RECURRENT CLOSTRIDIOIDES DIFFICILE INFECTION: A MULTI-CENTER RANDOMIZED TRIAL
Authors: Kao D , Wong K , Lee C , Steiner T , Franz R , McDougall C , Silva M , Yaskina M , Walter J , Loo V , Loebenberg R , Xu H , Louie T 
Published: February 2024

Abstract

Background
Fecal microbiota transplantation (FMT) is the most effective therapy in the treatment of recurrent Clostridioides difficile infection (rCDI), and can be offered in fresh, frozen or lyophilized formulation with similar efficacy. Microbial engraftment is thought to be one of the mechanisms mediating its efficacy. However, the importance of microbes has been questioned by two small preliminary clinical studies that showed sterile fecal filtrate could prevent C. difficile recurrence.

Aims
To establish whether lyophilized sterile fecal filtrate (LSFF) is noninferior to lyophilized FMT (LFMT) in efficacy

Methods
In this double-blind, non-inferiority study conducted in 4 academic centers in Alberta and British Columbia, we randomized rCDI patients with ≥ 3 CDI episodes to either LSFF or LFMT at a 1:1 ratio between 2019 and 2023.The non inferiority margin was 10%. Each treatment dose consisted of 15 oral capsules. Participants who failed the assigned treatments were offered open-label LFMT. An interim analysis was planned after reaching 50% of recruitment target (124/248 participants). Primary outcome was the proportion of participants without CDI recurrence 8 weeks following assigned treatment. Secondary outcomes included 1) the proportion of participants without CDI recurrence 24 weeks following assigned treatment, 2) serious adverse events (mortality, hospitalization and infections related to treatments), and 3) minor adverse events (nausea, vomiting, abdominal pain and fever). Exploratory outcomes included changes in quality of life, stool microbial composition analyses, as well as patient preferences.

Results
137 participants were randomized (mean [SD] age, 61.2 [18.6] years; 89 women [65.4%]; mean CDI episodes 3.8) to LFMT group (66 participants) and LSFF (71 participants) group. In per-protocol analysis, prevention of rCDI 8 weeks after assigned treatment was achieved in 63.8% of participants in LSFF group and 86.9% in LFMT group (difference, -23.1%), resulting in trial termination. Serious adverse events were infrequent: 4 hospitalizations deemed not related and 1 hospitalization possibly related, and 1 death from COVID deemed not related to assigned treatment. Minor adverse events were self-limited and infrequent: nausea (6), vomiting (2), abdominal discomfort (15) and fever (2).

Conclusions
Among adults with rCDI, LSFF was inferior to LFMT by oral capsules in preventing recurrent infection over 8 weeks. The result emphasizes the importance of microbes in mediating FMT efficacy. Preserving microbial viability in future development of microbial therapeutics is paramount.

Funding Agencies
CIHR