Pancreatic glycoprotein 2 is a first line of defense for mucosal protection in intestinal inflammation

Human cell surface-AAV interactomes identify LRP6 as blood-brain barrier transcytosis receptor and immune cytokine IL3 as AAV9 binder

Adeno-associated viruses (AAVs) are foundational gene delivery tools for basic science and clinical therapeutics. However, lack of mechanistic insight, especially for engineered vectors created by directed evolution, can hamper their application. Here, we adapt an unbiased human cell microarray platform to determine the extracellular and cell surface interactomes of natural and engineered AAVs. We identify a naturally-evolved and serotype-specific interaction between the AAV9 capsid and human interleukin 3 (IL3), with possible roles in host immune modulation, as well as lab-evolved low-density lipoprotein receptor-related protein 6 (LRP6) interactions specific to engineered capsids with enhanced blood-brain barrier crossing in non-human primates after intravenous administration. The unbiased cell microarray screening approach also allows us to identify off-target tissue binding interactions of engineered brain-enriched AAV capsids that may inform vectors' peripheral organ tropism and side effects. Our cryo-electron tomography and AlphaFold modeling of capsid-interactor complexes reveal LRP6 and IL3 binding sites. These results allow confident application of engineered AAVs in diverse organisms and unlock future target-informed engineering of improved viral and non-viral vectors for non-invasive therapeutic delivery to the brain.

The Pax transcription factor EGL-38 links EGFR signaling to assembly of a cell-type specific apical extracellular matrix in the Caenorhabditis elegans vulva

The surface of epithelial tissues is covered by an apical extracellular matrix (aECM). The aECMs of different tissues have distinct compositions to serve distinct functions, yet how a particular cell type assembles the proper aECM is not well understood. We used the cell-type specific matrix of the C. elegans vulva to investigate the connection between cell identity and matrix assembly. The vulva is an epithelial tube composed of seven cell types descending from EGFR/Ras-dependent (1°) and Notch-dependent (2°) lineages. Vulva aECM contains multiple Zona Pellucida domain (ZP) proteins, which are a common component of aECMs across life. ZP proteins LET-653 and CUTL-18 assemble on 1° cell surfaces, while NOAH-1 assembles on a subset of 2° surfaces. All three ZP genes are broadly transcribed, indicating that cell-type specific ZP assembly must be determined by features of the destination cell surface. The paired box (Pax) transcription factor EGL-38 promotes assembly of 1° matrix and prevents inappropriate assembly of 2° matrix, suggesting that EGL-38 promotes expression of one or more ZP matrix organizers. Our results connect the known signaling pathways and various downstream effectors to EGL-38/Pax expression and the ZP matrix component of vulva cell fate execution. We propose that dedicated transcriptional networks may contribute to cell-appropriate assembly of aECM in many epithelial organs.

Highlights

C. elegans vulva apical extracellular matrix is cell-type specific Broadly transcribed Zona Pellucida domain proteins assemble in specific matricesThe Pax2/5/8 homolog EGL-38 promotes assembly of the 1° vulva cell matrixEGL-38 expression and 1° cell matrix assembly depend on EGFR signaling.

Antimicrobial glycoprotein 2 (GP2) in gallstones, bile fluid and peribiliary glands of patients with primary sclerosing cholangitis

BACKGROUND

Glycoprotein-2 (GP2) IgA is a predictor of disease severity in primary sclerosing cholangitis (PSC). We examined GP2's occurrence in the biliary tract, the site of inflammation.

METHODS

GP2 was analyzed using ELISA, immunoblotting, mass spectrometry, and immunohistochemistry. The samples included: 20 bile and 30 serum samples from PSC patients, 23 bile and 11 serum samples from patients with gallstone disease (GD), 15 bile samples from healthy individuals undergoing liver-donation surgery (HILD), 20 extracts of gallstones (GE) obtained during cholecystectomy, and 101 blood-donor sera.

RESULTS

Biliary GP2 concentrations were significantly higher in patients with PSC and GD than in HILD (p < 0.0001). Serum GP2 levels were similar in PSC and GD patients, and controls, but lower than in bile (p < 0.0001). GP2 was detected in all 20 GEs. Mass spectrometry identified GP2 in the bile of 2 randomly selected GD and 2 PSC patients, and in none of 2 HILD samples. GP2 was found in peribiliary glands in 8 out of 12 PSC patients, showing morphological changes in acinar cells, but not in GD-gallbladders.

CONCLUSIONS

GP2 is present in bile of PSC and GD patients. It is synthesized in the peribiliary glands of PSC patients, supporting a pathogenic role for biliary GP2 in PSC.

Natural Adeno-Associated Virus Serotypes and Engineered Adeno-Associated Virus Capsid Variants: Tropism Differences and Mechanistic Insights

Today, adeno-associated virus (AAV)-based vectors are arguably the most promising in vivo gene delivery vehicles for durable therapeutic gene expression. Advances in molecular engineering, high-throughput screening platforms, and computational techniques have resulted in a toolbox of capsid variants with enhanced performance over parental serotypes. Despite their considerable promise and emerging clinical success, there are still obstacles hindering their broader use, including limited transduction capabilities, tissue/cell type-specific tropism and penetration into tissues through anatomical barriers, off-target tissue biodistribution, intracellular degradation, immune recognition, and a lack of translatability from preclinical models to clinical settings. Here, we first describe the transduction mechanisms of natural AAV serotypes and explore the current understanding of the systemic and cellular hurdles to efficient transduction. We then outline progress in developing designer AAV capsid variants, highlighting the seminal discoveries of variants which can transduce the central nervous system upon systemic administration, and, to a lesser extent, discuss the targeting of the peripheral nervous system, eye, ear, lung, liver, heart, and skeletal muscle, emphasizing their tissue and cell specificity and translational promise. In particular, we dive deeper into the molecular mechanisms behind their enhanced properties, with a focus on their engagement with host cell receptors previously inaccessible to natural AAV serotypes. Finally, we summarize the main findings of our review and discuss future directions.

From ASCA breakthrough in Crohn's disease and Candida albicans research to thirty years of investigations about their meaning in human health

Anti-Saccharomyces cerevisiae antibodies (ASCA) are human antibodies that can be detected using an enzyme-linked immunosorbent assay involving a mannose polymer (mannan) extracted from the cell wall of the yeast S. cerevisiae. The ASCA test was developed in 1993 with the aim of differentiating the serological response in two forms of inflammatory bowel disease (IBD), Crohn's disease and ulcerative colitis. The test, which is based on the detection of anti-oligomannosidic antibodies, has been extensively performed worldwide and there have been hundreds of publications on ASCA. The earlier studies concerned the initial diagnostic indications of ASCA and investigations then extended to many human diseases, generally in association with studies on intestinal microorganisms and the interaction of the micro-mycobiome with the immune system. The more information accumulates, the more the mystery of the meaning of ASCA deepens. Many fundamental questions remain unanswered. These questions concern the heterogeneity of ASCA, the mechanisms of their generation and persistence, the existence of self-antigens, and the relationship between ASCA and inflammation and autoimmunity. This review aims to discuss the gray areas concerning the origin of ASCA from an analysis of the literature. Structured around glycobiology and the mannosylated antigens of S. cerevisiae and Candida albicans, this review will address these questions and will try to clarify some lines of thought. The importance of the questions relating to the pathophysiological significance of ASCA goes far beyond IBD, even though these diseases remain the preferred models for their understanding.

Glycoprotein 2 as a gut gate keeper for mucosal equilibrium between inflammation and immunity

Glycoprotein 2 (GP2) is a widely distributed protein in the digestive tract, contributing to mucosal barrier maintenance, immune homeostasis, and antigen-specific immune response, while also being linked to inflammatory bowel disease (IBD) pathogenesis. This review sheds light on the extensive distribution of GP2 within the gastrointestinal tract and its intricate interplay with the immune system. Furthermore, the significance of GP2 autoantibodies in diagnosing and categorizing IBD is underscored, alongside the promising therapeutic avenues for modulating GP2 to regulate immunity and maintain mucosal balance.

Generation of β-like cell subtypes from differentiated human induced pluripotent stem cells in 3D spheroids

Since the identification of four different pancreatic β-cell subtypes and bi-hormomal cells playing a role in the diabetes pathogenesis, the search for in vitro models that mimics such cells heterogeneity became a key priority in experimental and clinical diabetology. We investigated the potential of human induced pluripotent stem cells to lead to the development of the different β-cells subtypes in honeycomb microwell-based 3D spheroids. The glucose-stimulated insulin secretion confirmed the spheroids functionality. Then, we performed a single cell RNA sequencing of the spheroids. Using a knowledge-based analysis with a stringency on the pancreatic markers, we extracted the β-cells INS+/UCN3+ subtype (11%; β1-like cells), the INS+/ST8SIA1+/CD9- subtype (3%, β3-like cells) and INS+/CD9+/ST8SIA1-subtype (1%; β2-like cells) consistently with literature findings. We did not detect the INS+/ST8SIA1+/CD9+ cells (β4-like cells). Then, we also identified four bi-hormonal cells subpopulations including δ-like cells (INS+/SST+, 6%), γ-like cells (INS+/PPY+, 3%), α-like-cells (INS+/GCG+, 6%) and ε-like-cells (INS+/GHRL+, 2%). Using data-driven clustering, we extracted four progenitors' subpopulations (with the lower level of INS gene) that included one population highly expressing inhibin genes (INHBA+/INHBB+), one population highly expressing KCNJ3+/TPH1+, one population expressing hepatocyte-like lineage markers (HNF1A+/AFP+), and one population expressing stem-like cell pancreatic progenitor markers (SOX2+/NEUROG3+). Furthermore, among the cycling population we found a large number of REST+ cells and CD9+ cells (CD9+/SPARC+/REST+). Our data confirm that our differentiation leads to large β-cell heterogeneity, which can be used for investigating β-cells plasticity under physiological and pathophysiological conditions.

The oral-gut axis: a missing piece in the IBD puzzle

Inflammatory bowel disease (IBD) is a multifactorial intractable intestinal disease. Focusing on only one facet of the pathogenesis of IBD is insufficient to fully capture the complexity of the disease, and results in limited advance in clinical management. Therefore, it is critical to dissect the interactions amongst the multifarious contributors to the pathogenesis to comprehensively understand its pathology and subsequently improve clinical outcomes. In this context, the systemic interactions between organs, particularly the oral-gut axis mediated by host immune cells and resident microorganisms, have garnered significant attention in IBD research. More specifically, periodontal disease such as periodontitis has been implicated in augmenting intestinal inflammation beyond the confines of the oral cavity. There is mounting evidence suggesting that potentially harmful oral resident bacteria, termed pathobionts, and pro-inflammatory immune cells from the oral mucosa can migrate to the gastrointestinal tract, thereby potentiating intestinal inflammation. This article aims to provide a holistic overview of the causal relationship between periodontal disease and intestinal inflammation. Furthermore, we will discuss potential determinants that facilitate the translocation of oral pathobionts into the gut, a key event underpinning the oral-gut axis. Unraveling the complex dynamics of microbiota and immunity in the oral-gut continuum will lead to a better understanding of the pathophysiology inherent in both oral and intestinal diseases and the development of prospective therapeutic strategies.

Polysaccharide from Smilax glabra Roxb Mitigates Intestinal Mucosal Damage by Therapeutically Restoring the Interactions between Gut Microbiota and Innate Immune Functions

Smilax glabra Roxb (S. glabra) is a conventional Chinese medicine that is mainly used for the reliability of inflammation. However, bioactive polysaccharides from S. glabra (SGPs) have not been thoroughly investigated. Here, we demonstrate for the first time that SGPs preserve the integrity of the gut epithelial layer and protect against intestinal mucosal injury induced by dextran sulfate sodium. Mechanistically, SGPs mitigated colonic mucosal injury by restoring the association between the gut flora and innate immune functions. In particular, SGPs increased the number of goblet cells, reduced the proportion of apoptotic cells, improved the differentiation of gut tight junction proteins, and enhanced mucin production in the gut epithelial layer. Moreover, SGPs endorsed the propagation of probiotic bacteria, including Lachnospiraceae bacterium, which strongly correlated with decreased pro-inflammatory cytokines via the blocking of the TLR-4 NF-κB and MyD88 pathways. Overall, our study establishes a novel use of SGPs for the treatment of inflammatory bowel disease (IBD)-associated mucosal injury and provides a basis for understanding the therapeutic effects of natural polysaccharides from the perspective of symbiotic associations between host innate immune mechanisms and the gut microbiome.

Quantitative TMT-based proteomics revealing host, dietary and microbial proteins in bovine faeces including barley serpin Z4, a prominent component in the head of beer

There has been little information about the proteome of bovine faeces or about the contribution to the faecal proteome of proteins from the host, the feed or the intestinal microbiome. Here, the bovine faecal proteome and the origin of its component proteins was assessed, while also determining the effect of treating barley, the major carbohydrate in the feed, with either ammonia (ATB) or sodium propionate (PTB) preservative. Healthy continental crossbreed steers were allocated to two groups and fed on either of the barley-based diets. Five faecal samples from each group were collected on Day 81 of the trial and analysed by quantitative proteomics using nLC-ESI-MS/MS after tandem mass tag labelling. In total, 281 bovine proteins, 199 barley proteins, 176 bacterial proteins and 190 archaeal proteins were identified in the faeces. Mucosal pentraxin, albumin and digestive enzymes were among bovine proteins identified. Serpin Z4 a protease inhibitor was the most abundant barley protein identified which is also found in barley-based beer, while numerous microbial proteins were identified, many originating bacteria from Clostridium, while Methanobrevibacter was the dominant archaeal genus. Thirty-nine proteins were differentially abundant between groups, the majority being more abundant in the PTB group compared to the ATB group. SIGNIFICANCE: Proteomic examination of faeces is becoming a valuable means to assess the health of the gastro-intestinal tract in several species, but knowledge on the proteins present in bovine faeces is limited. This investigation aimed to characterise the proteome of bovine faecal extracts in order to evaluate the potential for investigations of the proteome as a means to assess the health, disease and welfare of cattle in the future. The investigation was able to identify proteins in bovine faeces that had been (i) produced by the individual cattle, (ii) present in the barley-based feed eaten by the cattle or (iii) produced by bacteria and other microbes in the rumen or intestines. Bovine proteins identified included mucosal pentraxin, serum albumin and a variety of digestive enzymes. Barley proteins found in the faeces included serpin Z4, a protease inhibitor that is also found in beer having survived the brewing process. Bacterial and archaeal proteins in the faecal extracts were related to several pathways related to the metabolism of carbohydrates. The recognition of the range of proteins that can be identified in bovine faeces raises the possibility that non-invasive sample collection of this material could provide a novel diagnostic approach to cattle health and welfare.

Pancreatic Involvement in the Course of Inflammatory Bowel Disease in Children-A Multi-Center Study

The coexistence of inflammatory bowel disease (IBD) with pancreatic pathology is rare in children. A retrospective analysis of data from 1538 children diagnosed with IBD in 2014-2021 was conducted to determine the frequency and causes of pancreatitis and asymptomatic hyperlipasemia (HL) or hyperamylasemia (HA) in this group of patients. Among the 176 children (11.4%) with pancreatic involvement (PI), acute pancreatitis (AP) was diagnosed in 77 children (43.8%), and HA or HL was observed in 88 children (50.0%). Only a few patients were diagnosed with autoimmune or chronic pancreatitis (6.2%). PI was observed at the time of the IBD diagnosis in 26.1% of the cases. A total of 54.5% of the patients had moderate to severe IBD, and 96% had colonic involvement at the time of diagnosis of PI. Idiopathic PI was the most common (57%), followed by drug-induced PI (37%) and azathioprine (AZA). In patients with AZA-induced AP, the successful introduction of 6-mercaptopurine (6-MP) to therapy was noted in 62.5% of the children. Our results suggest that routine monitoring of pancreatic enzymes in patients with IBD should be performed, especially after the initiation of the AZA treatment. The presence of transient HA/HL in IBD does not necessarily indicate pancreatic pathology.

Cholesterol sulfate limits neutrophil recruitment and gut inflammation during mucosal injury

During mucosal injury, intestinal immune cells play a crucial role in eliminating invading bacteria. However, as the excessive accumulation of immune cells promotes inflammation and delays tissue repair, it is essential to identify the mechanism that limits the infiltration of immune cells to the mucosal-luminal interface. Cholesterol sulfate (CS) is the lipid product of the sulfotransferase SULT2B1 and suppresses immune reactions by inhibiting DOCK2-mediated Rac activation. In this study, we aimed to elucidate the physiological role of CS in the intestinal tract. We found that, in the small intestine and colon, CS is predominantly produced in the epithelial cells close to the lumen. While dextran sodium sulfate (DSS)-induced colitis was exacerbated in Sult2b1-deficient mice with increased prevalence of neutrophils, the elimination of either neutrophils or intestinal bacteria in Sult2b1-deficient mice attenuated disease development. Similar results were obtained when the Dock2 was genetically deleted in Sult2b1-deficient mice. In addition, we also show that indomethacin-induced ulcer formation in the small intestine was exacerbated in Sult2b1-deficient mice and was ameliorated by CS administration. Thus, our results uncover that CS acts on inflammatory neutrophils, and prevents excessive gut inflammation by inhibiting the Rac activator DOCK2. The administration of CS may be a novel therapeutic strategy for inflammatory bowel disease and non-steroidal anti-inflammatory drug-induced ulcers.

A new machine learning based computational framework identifies therapeutic targets and unveils influential genes in pancreatic islet cells

Pancreatic islets comprise a group of cells that produce hormones regulating blood glucose levels. Particularly, the alpha and beta islet cells produce glucagon and insulin to stabilize blood glucose. When beta islet cells are dysfunctional, insulin is not secreted, inducing a glucose metabolic disorder. Identifying effective therapeutic targets against the disease is a complicated task and is not yet conclusive. To close the wide gap between understanding the molecular mechanism of pancreatic islet cells and providing effective therapeutic targets, we present a computational framework to identify potential therapeutic targets against pancreatic disorders. First, we downloaded three transcriptome expression profiling datasets pertaining to pancreatic islet cells (GSE87375, GSE79457, GSE110154) from the Gene Expression Omnibus database. For each dataset, we extracted expression profiles for two cell types. We then provided these expression profiles along with the cell types to our proposed constrained optimization problem of a support vector machine and to other existing methods, selecting important genes from the expression profiles. Finally, we performed (1) an evaluation from a classification perspective which showed the superiority of our methods against the baseline; and (2) an enrichment analysis which indicated that our methods achieved better outcomes. Results for the three datasets included 44 unique genes and 10 unique transcription factors (SP1, HDAC1, EGR1, E2F1, AR, STAT6, RELA, SP3, NFKB1, and ESR1) which are reportedly related to pancreatic islet functions, diseases, and therapeutic targets.

Human glycoprotein-2 expressed in Brunner glands - A putative autoimmune target and link between Crohn's and coeliac disease

Glycoprotein 2 (GP2) is an autoantigen in Crohn's (CD) and coeliac disease (CeD). We assessed GP2-isoform (GP2_1-4)-expression in intestinal biopsies of paediatric patients with CD, CeD, ulcerative colitis (UC), and healthy children (HC). Transcription of GP2_1-4 was elevated in proximal small intestine in CeD and CD patients (only GP2_2/4) compared to jejunum (CeD/CD) and large bowel (CD). CeD patients demonstrated higher duodenal GP2_2/4-mRNA levels compared to HC/UC patients whereas CD patients showed higher GP2₄-mRNA levels compared to UC patients. Duodenal synthesis of only small GP2 isoforms (GP2_3/4) was demonstrated in epithelial cells in patients/HC and in Brunner glands (also large isoforms) with a more frequent apical location in CD/CeD patients. All four GP2 isoforms interacted with gliadin and phosphopeptidomannan. Gliadin digestion improved binding to GP2 isoforms. GP2_1-4 binding to CeD/CD-related antigens, elevated duodenal GP2_1-4-mRNA transcription, and GP2-protein secretion in Brunner glands of CeD/CD patients suggest an autoimmune CeD/CD link.

Transcriptome profiling Revealed the potential mechanisms of Shen Lin Bai Zhu San n-butanol extract on DSS induced Colitis in Mice and LC-MS analysis

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic and recurrent inflammatory disorder in gastrointestinal tract. Shen Ling Bai Zhu San (SLBZS), which has a long history of use in Traditional Chinese Medicine (TCM), has been widely used to treat gastrointestinal diseases. The isolated fractions of TCM have also been proved to possess an important potential for treating diseases, which are due to their effective components.

PURPOSE

In this study, we examined the possibility that SLBZS and its isolated active fractions may prevent DSS-induced colitis, and investigated the potential mechanisms by regulating genetic profile of colon.

METHODS

Colitis mice were induced by 2.5% DSS for 7 days, and then SLBZS and different SLBZS extracts were administrated to protect the mice for 7 days. Body weight, diarrhea, bleeding in stool, colon length, spleen weight, cytokines of serum and colon and pathology of colon were assessed. The level of Ginsenoside Rg1, Re and Rb1 in different SLBZS extracts and qualitative analysis of n-butanol extract of SLBZS (S-Nb) was performed by HPLC and LC-MS, respectively. And the effects of S-Nb on the transcriptome in colitis were investigated.

RESULTS

Our results showed that SLBZS and S-Nb significantly regained body weight, reduced DAI, splenomegaly and the length of colon and attenuated histological damage of the colon. Meanwhile, SLBZS and S-Nb markedly reduced the levels of TNF-α, IL-1β and IL-6 and increased the level of IL-10 in serum and colon. These effects may be associated with the high levels of Ginsenoside Rg1, Re and Rb1 and rich variety of compounds in S-Nb including 6 ginsenosides, glycyrrhizin, L-tryptophan, and so on. Transcriptome analysis revealed that S-Nb selectively regulated 103 differentially expressed genes (DEGs), 36 of which were changed in DSS-induced mice. And the genes of Per2, Per3, Npy and Serpina3m were closely related to colitis and also restored by S-Nb with different extent. Remarkably, these DEGs modulated the biological functions of colitis mice, including extracellular region, response to external stimulus, MAPK signaling pathway and arginine and proline metabolism.

CONCLUSIONS

These data indicated that SLBZS and S-Nb blunted DSS-induced colitis by modulating differentially expression gene profile and biological functions based on their ginsenosides and rich compounds.

Tumor resident microbiota and response to therapies: An insight on tissue bacterial microbiota

The role of the intestinal microbiota in the promotion, progression, and response to therapies is gaining importance, but recent studies confirm the presence of microbiota also in the tumor, thus becoming a component of the tumor microenvironment. There is not much knowledge on the characteristics and mechanisms of action of the tumor resident microbiota, but there are already indications of its involvement in conditioning the response to therapies. In this review, we discuss recent publications on the interaction between microbiota and anticancer treatments, mechanisms of resistance and possible strategies for manipulating the microbiota that could improve treatments in a personalized medicine perspective.

GP2-expressing cells: a new guardian with divergent functions in the intestine, eyes, and nose

GP (glycoprotein)-2, originally identified as a predominant membranous component of pancreatic acinar cells, has attracted the interest of researchers in mucosal immunology for its role as a functional molecule specific for antigen-sampling cells in the intestinal Peyer's patches. GP2 is involved in the detection of pathological bacteria and is also histologically useful for the identification of the M cell lineage and their differentiation in lymphoid tissues. Subsequent immunohistochemistry for GP2 has revealed a broad distribution of M cells and related cells in the nasopharyngeal lymphoid tissues, conjunctiva, tear duct, and airway. Especially, GP2 cells in the paranasal sinuses and tear duct have been identified as novel types of epithelial cells. The systematic administration of RANKL can induce extra-M cells in conventional epithelia of body. The production and release of GP2 by conjunctival goblet cells and several mucous glands suggests leading roles for mucous cells in protection, including the entrapment of microorganisms for infections. The ocular surface and conjunctiva are connected to the lacrimal sac, nasolacrimal duct, and further nasal cavity, comprising another canal that passes through the body. The broad distribution of GP2-expressingcells may indicate its function as a new guardian in the intestine, eyes, and nose, all of which are exposed to external milieu.

Symbiotic bacteria-dependent expansion of MR1-reactive T cells causes autoimmunity in the absence of Bcl11b

MHC class I-related protein 1 (MR1) is a metabolite-presenting molecule that restricts MR1-reactive T cells including mucosal-associated invariant T (MAIT) cells. In contrast to MAIT cells, the function of other MR1-restricted T cell subsets is largely unknown. Here, we report that mice in which a T cell-specific transcription factor, B-cell lymphoma/leukemia 11B (Bcl11b), was ablated in immature thymocytes (Bcl11b^∆iThy mice) develop chronic inflammation. Bcl11b^∆iThy mice lack conventional T cells and MAIT cells, whereas CD4⁺IL-18R⁺ αβ T cells expressing skewed Traj33 (Jα33)⁺ T cell receptors (TCR) accumulate in the periphery, which are necessary and sufficient for the pathogenesis. The disorders observed in Bcl11b^∆iThy mice are ameliorated by MR1-deficiency, transfer of conventional T cells, or germ-free conditions. We further show the crystal structure of the TCR expressed by Traj33⁺ T cells expanded in Bcl11b^∆iThy mice. Overall, we establish that MR1-reactive T cells have pathogenic potential.

Identification and characterization of murine glycoprotein 2-expressing intestinal dendritic cells

The intestinal lamina propria (LP) contains distinct subsets of classical dendritic cells (cDC), each playing key non-redundant roles in intestinal immune homeostasis. Here, we show that glycoprotein 2 (GP2), a GPI-anchored protein and receptor for bacterial type-I fimbriae, is selectively expressed by CD103+CD11b+ cDC in the murine small intestine (SI). GP2 expression was induced on CD103+CD11b+ cDC within the SI-LP and was regulated by IRF4, TGFβR1- and retinoic acid signalling. Mice selectively lacking Gp2 on CD103+CD11b+ cDC (huLang-Cre.gp2fl/fl mice) had normal numbers and proportions of innate and adaptive immune cells in the SI-LP suggesting that GP2 expression by CD103+CD11b+ cDC is not required for intestinal immune homoeostasis.

Diagnostic and prognostic role of pancreatic secretory granule membrane major glycoprotein 2 (GP2) immunohistochemistry: A TMA study on 27,681 tumors

Pancreatic secretory granule membrane major glycoprotein 2 (GP2) is a membrane component of zymogen granules which is abundantly secreted by pancreatic acinar cells. Because RNA based analyses suggest a strict limitation of GP2 expression to the pancreas in normal tissues, and a strong preference to pancreatic cancer among tumors, GP2 expression analysis might have diagnostic utility. To better understand the role of GP2 protein expression, GP2 was successfully analyzed in 27,965 tumor samples from 132 different tumor types and subtypes as well as 8 samples each of 76 different normal tissue types by immunohistochemistry in a tissue microarray format (TMA). GP2 immunostaining was seen in 14 of 16 (87.5 %) acinar cell carcinomas, 6 of 507 (1.2 %) ductal adenocarcinomas, and 3 of 99 neuroendocrine neoplasms of the pancreas (3.0 %). GP2 was also found in 23 extra-pancreatic tumor entities including several types of neuroendocrine neoplasms (14.3-58.8 %), prostatic adenocarcinomas (8.2-18.8 %), various other adenocarcinomas (0.1-7.7 %), and several categories of benign and malignant salivary gland tumors (2.3-3.1 %). A strong GP2 positivity was only seen in 6 tumor categories including 50 % of 16 pancreatic acinus cell carcinomas, 11.8 % of 17 neuroendocrine tumors of the lung, 1.3 % of 80 primary Gleason 4 + 4 % and 0.6 % of 181 recurrent prostate cancers, as well as 0.8 % of 133 adenocarcinomas of the lung. In a cohort of 14,747 prostate cancers with follow up data, GP2 immunostaining was strongly linked to advanced pT stage, high Gleason grade, lymph node metastasis, and recurrence free survival (p < 0.0001 each). The prognostic impact of GP2 positivity was independent of established parameters in TMPRSS2:ERG fusion-negative cancers (p < 0.0001). In summary, our data show that GP2 is preferentially expressed in acinar cell carcinomas of the pancreas but the glycoprotein can - rarely - also be expressed in a variety of other tumor entities.

Surfactin Mitigates a High-Fat Diet and Streptozotocin-Induced Type 2 Diabetes through Improving Pancreatic Dysfunction and Inhibiting Inflammatory Response

Surfactin from Bacillus amyloliquefaciens fmb50 was utilized to treat mice with type 2 diabetes (T2DM) induced by a high-fat diet/streptozotocin (HFD/STZ). Our group’s earlier research indicated that surfactin could lower blood glucose and mitigate liver dysfunction to further improve HFD/STZ-induced T2DM through modulating intestinal microbiota. Thus, we further investigated the effects of surfactin on the pancreas and colon in mice with T2DM to elucidate the detailed mechanism. In the present study, mice with HFD/STZ-induced T2DM had their pancreatic and colon inflammation, oxidative stress, and endoplasmic reticulum stress (ERS) reduced when given oral surfactin at a dose of 80 mg/kg body weight. According to further research, surfactin also improved glucose metabolism by activating the phosphatidylinositol kinase (PI3K)/protein kinase B (Akt) signaling pathway, further protecting islets β-cell, promoting insulin secretion, inhibiting glucagon release and mitigating pancreas dysfunction. Additionally, after surfactin treatment, the colon levels of the tight junction proteins Occludin and Claudin-1 of T2DM mice were considerably increased by 130.64% and by 36.40%, respectively. These findings revealed that surfactin not only ameliorated HFD/STZ-induced pancreas inflammation and dysfunction and preserved intestinal barrier dysfunction and gut microbiota homeostasis but also enhanced insulin sensitivity and glucose homeostasis in T2DM mice. Finally, in the further experiment, we were able to demonstrate that early surfactin intervention might delay the development of T2DM caused by HFD/STZ, according to critical biochemical parameters in serum.

Pathological features-based targeted delivery strategies in IBD therapy: A mini review

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by a complex and dysfunctional immune response. Currently, IBD is incurable, and patients with IBD often need to take drugs for life. However, as the traditional systemic treatment strategies for IBD do not target the site of inflammation, only limited efficacy can be obtained from them. Moreover, the possibility of serious side effects stemming from the systemic administration or redistribution of drugs in the body is high when conventional drug formulations are used. Therefore, a targeted drug-delivery system for IBD should be considered. Based on the pathological features related to IBD, the new targeted drug-delivery strategy can directly transfer the drug to the inflammatory site, thus enhancing the accumulation of the drugs and reducing side effects. This article reviews the pathological features of IBD and the application of the IBD-targeted delivery system based on different pathological features, and discusses the challenges and new prospects in this field.

Gut microbiota alternation under the intestinal epithelium-specific knockout of mouse Piga gene

Crosstalk between the gut microbiota and intestinal epithelium shapes the gut environment and profoundly influences the intestinal immune homeostasis. Glycosylphosphatidylinositol anchored proteins (GPI – APs) contribute to a variety of gut-associated immune functions, including microbial surveillance and defense, and epithelial cell polarity. Properly polarised epithelial cells are essential for the establishment of the barrier function of gut epithelia. The Piga gene is one among seven genes that encode for an enzyme which is involved in the first step of GPI-anchor biosynthesis. This is the first study reporting a knockout of the intestinal epithelial cell-specific Piga gene (Piga-/-) and its association with the gut microbiota in mice using a whole metagenome shotgun-based sequencing approach. An overall reduced microbiota diversity has been observed in the Piga-/- group as compared to the control group (ANOVA p = 0.34). The taxonomic biomarkers, namely: Gammaproteobacteria (class), Enterobacterales (order), Enterobacteriaceae (family), Escherichia (genus), Proteus (genus) and Escherichia coli (species), increased more in the Piga-/- mice as compared to in the control group. Further, the pathogenic E. coli strains, namely E. coli O157:H7 str. EDL 933 (EHEC), E. coli CFT073 (UPEC) and E. coli 536 (UPEC), were found in the Piga-/- mice which also harbored virulence factor transporters. In addition, the taxa responsible for short chain fatty acid production were decreased in the Piga-/- group. The Piga-/- mice gut harbored an increased number of microbial functions responsible for the survival of pathogens in the inflamed gut environment. Our observations clearly indicate that the Piga-/- mice gut might have an overall enhancement in pathogenic behaviour and reduced capabilities beneficial to health.

Specific Temporal Requirement of Prox1 Activity During Pancreatic Acinar Cell Development

BACKGROUND AND AIMS

An interactive regulatory network assembled through the induction and downregulation of distinct transcription factors governs acinar cell maturation. Understanding how this network is built is relevant for protocols of directed pancreatic acinar differentiation. The murine transcription factor Prox1 is highly expressed in multipotent pancreatic progenitors and in various mature pancreatic cell types except for acinar cells. In this study, we investigated when is Prox1 expression terminated in developing acinar cells and the potential involvement of its activity in acinar cell specification/differentiation. We also investigated the effects of sustained Prox1 expression in acinar maturation and maintenance.

METHODS

Prox1 acinar expression was analyzed by immunofluorescence and confocal microscopy. Prox1-null embryos (Prox1GFPCre/Δ), Prox1AcOE transgenic mice, histologic and immunostaining methods, transmission electron microscopy, functional assays, and quantitative RNA and RNA-sequencing methods were used to investigate the effects of Prox1 functional deficiency and sustained Prox1 expression in acinar maturation and homeostasis.

RESULTS

Immunostaining results reveal transient Prox1 expression in newly committed embryonic acinar cells. RNA-sequencing demonstrate precocious expression of multiple "late" acinar genes in the pancreas of Prox1GFPCre/Δ embryos. Prox1AcOE transgenic mice carrying sustained Prox1 acinar expression have relatively normal pancreas development. In contrast, Prox1AcOE adult mice have severe pancreatic alterations involving reduced acinar gene expression, abnormal acinar secretory granules, acinar atrophy, increased endoplasmic reticulum stress, and mild chronic inflammation.

CONCLUSION

Prox1 transient expression in early acinar cells is necessary for correct sequential gene expression. Prox1 expression is terminated in developing acinar cells to complete maturation and to preserve homeostasis.

Intestinal homeostasis and inflammation: gut microbiota at the crossroads of pancreas-intestinal barrier axis

The pancreas contains exocrine glands, which release enzymes (e.g., amylase, trypsin, and lipase) that are important for digestion and islets, which produce hormones. Digestive enzymes and hormones are secreted from the pancreas into the duodenum and bloodstream, respectively. Growing evidence suggests that the roles of the pancreas extend to not only the secretion of digestive enzymes and hormones but also to the regulation of intestinal homeostasis and inflammation (e.g., mucosal defense to pathogens and pathobionts). Organ crosstalk between the pancreas and intestine is linked to a range of physiological, immunological, and pathological activities, such as the regulation of the gut microbiota by the pancreatic proteins and lipids, the retroaction of the gut microbiota on the pancreas, the relationship between inflammatory bowel disease, and pancreatic diseases. We herein discuss the current understanding of the pancreas–intestinal barrier axis and the control of commensal bacteria in intestinal inflammation.

Structure of the decoy module of human glycoprotein 2 and uromodulin and its interaction with bacterial adhesin FimH

Glycoprotein 2 (GP2) and uromodulin (UMOD) filaments protect against gastrointestinal and urinary tract infections by acting as decoys for bacterial fimbrial lectin FimH. By combining AlphaFold2 predictions with X-ray crystallography and cryo-EM, we show that these proteins contain a bipartite decoy module whose new fold presents the high-mannose glycan recognized by FimH. The structure rationalizes UMOD mutations associated with kidney diseases and visualizes a key epitope implicated in cast nephropathy.

AlphaFold2 predictions, X-ray crystallography and cryo-EM analyses reveal how related human glycoproteins GP2 and uromodulin catch pathogenic bacteria by presenting a high-mannose glycan that acts as a decoy for fimbrial adhesin FimH.

[The role of the microbiome in diseases of the pancreas]

BACKGROUND

The human body is inhabited by diverse microorganisms. Together, this so-called microbiome exerts important metabolic functions and contributes to the maintenance of health. At the same time, shifts in the microbiome composition may lead to disease.

OBJECTIVES

Review of the current literature about the role of the microbiome in diseases of the pancreas.

MATERIALS AND METHODS

Literature search in PubMed and Embase.

RESULTS

The exocrine pancreas is a major factor determining the composition and stability of the intestinal microbiome even in healthy people without pancreatic disease. Inflammatory diseases of the pancreas such as acute or chronic pancreatitis lead to reduced microbial diversity, loss of gut barrier stabilizing bacteria and an increase in facultative pathogens like Escherichia or Enterococcus. Even pancreatic cancer tissue harbours microbiota and mice models have shown that the growth of pancreatic cancer can be inhibited by microbiota ablation.

CONCLUSIONS

Inflammatory diseases of the pancreas lead to gut microbiome dysbiosis and tumor microbiota probably play a role in the development of pancreatic cancer. Until now, however, there is no proof that therapeutic microbiota modulation in individuals with pancreatic disease can improve mortality or quality of life. At this point, the analysis of the microbiome in pancreatic disease should only be performed in scientific studies.

Adhesion of enteropathogenic, enterotoxigenic and commensal Escherichia coli to the Major Zymogen Granule Membrane Glycoprotein 2

Pathogenic bacteria, such as enteropathogenic Escherichia coli (EPEC) and enterotoxigenic E. coli (ETEC), cause diarrhea in mammals. In particular, E. coli colonizes and infects the gastrointestinal tract via type 1 fimbriae (T1F). Here, the major zymogen granule membrane glycoprotein 2 (GP2) acts as a host cell receptor. GP2 is also secreted by the pancreas and various mucous glands, interacting with luminal type 1 fimbriae-positive E. coli. It is unknown whether GP2 isoforms demonstrate specific E. coli pathotype binding. In this study, we investigated interactions of human, porcine, and bovine EPEC and ETEC, as well as commensal E. coli isolates with human, porcine, and bovine GP2. We first defined pathotype- and host-associated FimH variants. Second, we could prove that GP2 isoforms bound to FimH variants to various degrees. However, the GP2-FimH interactions did not seem to be influenced by the host specificity of E. coli. In contrast, soluble GP2 affected ETEC infection and phagocytosis rates of macrophages. Preincubation of the ETEC pathotype with GP2 reduced the infection of cell lines. Furthermore, preincubation of E. coli with GP2 improved the phagocytosis rate of macrophages. Our findings suggest that GP2 plays a role in the defense against E. coli infection and in the corresponding host immune response.

IMPORTANCE Infection by pathogenic bacteria, such as certain Escherichia coli pathotypes, results in diarrhea in mammals. Pathogens, including zoonotic agents, can infect different hosts or show host specificity. There are Escherichia coli strains which are frequently transmitted between humans and animals, whereas other Escherichia coli strains tend to colonize only one host. This host specificity is still not fully understood. We show that glycoprotein 2 is a selective receptor for particular Escherichia coli strains or variants of the adhesin FimH but not a selector for a species-specific Escherichia coli group. We demonstrate that GP2 is involved in the regulation of colonization and infection and thus represents a molecule of interest for the prevention or treatment of disease.

Amelioration of Alzheimer's Disease by Gut-Pancreas-Liver-Brain Interaction in an App Knock-In Mouse Model

In this study, we observed disease progression, changes in the gut microbiota, and interactions among the brain, liver, pancreas, and intestine in a mouse model of Alzheimer's disease (AD), in addition to attempting to inhibit disease progression through the dietary supplementation of L-arginine and limonoids. Wild-type mice (WC) and AD mice were fed a normal diet (AC), a diet supplemented with L-arginine and limonoids (ALA), or a diet containing only limonoids (AL) for 12-64 weeks. The normal diet-fed WC and AC mice showed a decrease in the diversity of the gut microbiota, with an increase in the Firmicutes/Bacteroidetes ratio, and bacterial translocation. Considerable bacterial translocation to the pancreas and intense inflammation of the pancreas, liver, brain, and intestinal tissues were observed in the AC mice from alterations in the gut microbiota. The ALA diet or AL diet-fed mice showed increased diversity of the bacterial flora and suppressed oxidative stress and inflammatory responses in hepatocytes and pancreatic cells, bacterial translocation, and neurodegeneration of the brain. These findings suggest that L-arginine and limonoids help in maintaining the homeostasis of the gut microbiota, pancreas, liver, brain, and gut in AD mice.

Glycoprotein 2 in health and disease: lifting the veil

In 2020, we discovered glycoprotein 2 (GP2) variants associated with pancreatic cancer susceptibility in a genome-wide association study involving the Japanese population. Individuals carrying a missense coding variant (rs78193826) in the GP2 gene resulting in a p.V432M substitution had an approximately 1.5-fold higher risk of developing pancreatic cancer than those without this variant. GP2 is expressed on the inner surface of zymogen granules in pancreatic acinar cells, which are responsible for the sorting, storage and secretion of digestive enzymes. Upon neuronal, hormonal, or other stimulation, GP2 is cleaved from the membrane of zymogen granules and then secreted into the pancreatic duct and intestinal lumen. While the functions of GP2 remain poorly understood, emerging evidence suggests that it plays an antibacterial role in the gastrointestinal tract after being secreted from pancreatic acinar cells. Impaired GP2 functions may facilitate the adhesion of bacteria to the intestinal mucosa. In this review article, we summarize the role of GP2 in health and disease, emphasizing its functions in the gastrointestinal tract, as well as genetic variations in the GP2 gene and their associations with disease susceptibility. We hope that its robust genetic associations with pancreatic cancer, coupled with its emerging role in gastrointestinal mucosal immunity, will spur renewed research interest in GP2, which has been understudied over the past 30 years compared with its paralog uromodulin (UMOD).

Dendrobium officinale Polysaccharide Alleviates Intestinal Inflammation by Promoting Small Extracellular Vesicle Packaging of miR-433-3p

Dendrobium officinale polysaccharide (DOP) attenuates inflammatory bowel disease (IBD), but its role in regulating cross-talk between intestinal epithelial cells (IEC) and macrophages against IBD is unclear. This study aimed to investigate DOP protective effects on the intestinal inflammatory response through regulation by miRNA in small extracellular vesicles (sEVs). Our results show that DOP interfered with the secretion of small extracellular vesicles (DIEs) by IEC, which reduced the levels of inflammatory mediators. Increased miR-433-3p expression in DIEs was identified as an important protector against intestinal inflammation. DOP regulated the loading of miR-433-3p by hnRNPA2B1 into the intestinal sEV to increase the abundance of miR-433-3p. DIEs delivered miR-433-3p to lipopolysaccharide-induced macrophages and targeted the MAPK8 gene, leading to inhibition of the MAPK signaling pathway and reduced production of inflammatory cytokines. One protective mechanism of DOP is mediated by intestinal sEV containing miR-433-3p, which is a potential therapeutic agent for the prevention of inflammatory factor accumulation from excessive intestinal macrophage activity and for restoring homeostasis in the intestinal microenvironment.

Pancreatic Associated Manifestations in Pediatric Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are chronic relapsing inflammatory conditions of the gastrointestinal tract, encompassing Crohn’s disease (CD), ulcerative colitis (UC) and inflammatory bowel disease unclassified (IBD-U). They are currently considered as systemic disorders determined by a set of genetic predispositions, individual susceptibility and environmental triggers, potentially able to involve other organs and systems than the gastrointestinal tract. A large number of patients experiences one or more extraintestinal manifestations (EIMs), whose sites affected are mostly represented by the joints, skin, bones, liver, eyes, and pancreas. Pancreatic abnormalities are not uncommon and are often underestimated, encompassing acute and chronic pancreatitis, autoimmune pancreatitis, exocrine pancreatic insufficiency and asymptomatic elevation of pancreatic enzymes. In most cases they are the result of environmental triggers. However, several genetic polymorphisms may play a role as precipitating factors or contributing to a more severe course. The aim of this paper is to provide an updated overview on the available evidence concerning the etiology, pathogenesis and clinical presentation of pancreatic diseases in IBD pediatric patients.

Pancreatic Disorders in Children with Inflammatory Bowel Disease

Background and Objectives: Inflammatory bowel disease (IBD) is a chronic condition and mainly affects the intestines, however, the involvement of the other organs of the gastrointestinal tract (upper part, pancreas, and liver) have been observed. The coexistence of IBD with pancreatic pathology is rare, however, it has been diagnosed more frequently during recent years in the pediatric population. This article reviews the current literature on the most common pancreatic diseases associated with IBD in the pediatric population and their relationship with IBD activity and treatment. Materials and Methods: We performed a systematic review of data from published studies on pancreatic disorders, also reported as extraintestinal manifestations (EIMs), among children with IBD. We searched PubMed and Web of Science to identify eligible studies published prior to 25 April 2020. Results: Forty-four papers were chosen for analysis after a detailed inspection, which aimed to keep only the research studies (case control studies and cohort studies) or case reports on children and only those which were written in English. The manifestations of IBD-associated pancreatic disorders range from asymptomatic increase in pancreatic enzymes activity to severe disease such as acute pancreatitis. Acute pancreatitis (AP) induced by drugs, mainly thiopurine, seems to be the most- often-reported pancreatic disease associated with IBD in children. AP associated with other than drug etiologies, and chronic pancreatitis (CP), are rarely observed in the course of pediatric IBD. The pancreatic involvement can be strictly related to the activity of IBD and can also precede the diagnosis of IBD in some pediatric patients. The course of AP is mild in most cases and may occasionally lead to the development of CP, mainly in cases with a genetic predisposition. Conclusions: The involvement of the pancreas in the course of IBD may be considered as an EIM or a separate co-morbid disease, but it can also be a side effect of IBD therapy, therefore a differential diagnosis should always be performed. As the number of IBD incidences with concomitant pancreatic diseases is constantly increasing in the pediatric population, it is important to include pancreatic enzymes level measurement in the workup of IBD.