Intestinal microbiota imbalance resulted by anti-Toxoplasma gondii immune responses aggravate gut and brain injury.

BACKGROUND: Toxoplasma gondii infection affects a significant portion of the global population, leading to severe toxoplasmosis and, in immunocompromised patients, even death. During T. gondii infection, disruption of gut microbiota further exacerbates the damage to intestinal and brain barriers. Therefore, identifying imbalanced probiotics during infection and restoring their equilibrium can regulate the balance of gut microbiota metabolites, thereby alleviating tissue damage. METHODS: Vimentin gene knockout (vim-/-) mice were employed as an immunocompromised model to evaluate the influence of host immune responses on gut microbiota balance during T. gondii infection. Behavioral experiments were performed to assess changes in cognitive levels and depressive tendencies between chronically infected vim-/- and wild-type (WT) mice. Fecal samples were subjected to 16S ribosomal RNA (rRNA) sequencing, and serum metabolites were analyzed to identify potential gut probiotics and their metabolites for the treatment of T. gondii infection. RESULTS: Compared to the immunocompetent WT sv129 mice, the immunocompromised mice exhibited lower levels of neuronal apoptosis and fewer neurobehavioral abnormalities during chronic infection. 16S rRNA sequencing revealed a significant decrease in the abundance of probiotics, including several species of Lactobacillus, in WT mice. Restoring this balance through the administration of Lactobacillus murinus and Lactobacillus gasseri significantly suppressed the T. gondii burden in the intestine, liver, and brain. Moreover, transplantation of these two Lactobacillus spp. significantly improved intestinal barrier damage and alleviated inflammation and neuronal apoptosis in the central nervous system. Metabolite detection studies revealed that the levels of various Lactobacillus-related metabolites, including indole-3-lactic acid (ILA) in serum, decreased significantly after T. gondii infection. We confirmed that L. gasseri secreted much more ILA than L. murinus. Notably, ILA can activate the aromatic hydrocarbon receptor signaling pathway in intestinal epithelial cells, promoting the activation of CD8+ T cells and the secretion of interferon-gamma. CONCLUSION: Our study revealed that host immune responses against T. gondii infection severely disrupted the balance of gut microbiota, resulting in intestinal and brain damage. Lactobacillus spp. play a crucial role in immune regulation, and the metabolite ILA is a promising therapeutic compound for efficient and safe treatment of T. gondii infection.

Dietary algal-sourced zinc nanoparticles promote growth performance, intestinal integrity, and immune response of Nile tilapia (Oreochromis niloticus).

BACKGROUND: Trace elements play a crucial role in fish nutrition, with zinc (Zn) being one of the most important elements. BIO-sourced zinc nanoparticles were synthesized using the green microalga Pediastrum boryanum (BIO-ZnNPs, 29.35 nm). 30 or 60 mg/ kg dry feed of the BIO-ZnNPs (BIO-ZnNPs30 and BIO-ZnNPs60) were mixed with the Nile tilapia (Oreochromis niloticus) basal diet and fed to the fish for 8 weeks to evaluate their impact on fish growth, digestion, intestinal integrity, antioxidative status, and immunity. RESULTS: A significant enhancement was observed in all investigated parameters, except for the serum protein profile. BIO-ZnNPs at 60 mg/kg feed elevated the activities of reduced glutathione (GSH) and catalase (CAT), enzymatic antioxidants, but did not induce oxidative stress as reflected by no change in MDA level. Fish intestinal immunity was improved in a dose-dependent manner, in terms of improved morphometry and a higher count of acid mucin-producing goblet cells. Interleukin-8 (IL-8) was upregulated in BIO-ZnNPs30 compared to BIO-ZnNPs60 and control fish groups, while no significant expressions were noted in tumor necrosis factor-alpha (TNFα), nuclear factor kappa B (NFkB), and Caspase3 genes. CONCLUSION: Overall, BIO-ZnNPs inclusion at 60 mg/kg feed showed the most advantage in different scenarios, compared to BIO-ZnNPs at 30 mg/kg feed. The positive effects on growth and intestinal health suggest that BIO-ZnNPs supplementation of aquafeeds has many benefits for farmed fish.

CTLA-4-expressing ILC3s restrain interleukin-23-mediated inflammation.

Interleukin (IL-)23 is a major mediator and therapeutic target in chronic inflammatory diseases that also elicits tissue protection in the intestine at homeostasis or following acute infection1-4. However, the mechanisms that shape these beneficial versus pathological outcomes remain poorly understood. To address this gap in knowledge, we performed single-cell RNA sequencing on all IL-23 receptor-expressing cells in the intestine and their acute response to IL-23, revealing a dominance of T cells and group 3 innate lymphoid cells (ILC3s). Unexpectedly, we identified potent upregulation of the immunoregulatory checkpoint molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) on ILC3s. This pathway was activated by gut microbes and IL-23 in a FOXO1- and STAT3-dependent manner. Mice lacking CTLA-4 on ILC3s exhibited reduced regulatory T cells, elevated inflammatory T cells and more-severe intestinal inflammation. IL-23 induction of CTLA-4+ ILC3s was necessary and sufficient to reduce co-stimulatory molecules and increase PD-L1 bioavailability on intestinal myeloid cells. Finally, human ILC3s upregulated CTLA-4 in response to IL-23 or gut inflammation and correlated with immunoregulation in inflammatory bowel disease. These results reveal ILC3-intrinsic CTLA-4 as an essential checkpoint that restrains the pathological outcomes of IL-23, suggesting that disruption of these lymphocytes, which occurs in inflammatory bowel disease5-7, contributes to chronic inflammation.

Chicken intestinal organoids: a novel method to measure the mode of action of feed additives.

There is a rapidly growing interest in how the avian intestine is affected by dietary components and feed additives. The paucity of physiologically relevant models has limited research in this field of poultry gut health and led to an over-reliance on the use of live birds for experiments. The development of complex 3D intestinal organoids or "mini-guts" has created ample opportunities for poultry research in this field. A major advantage of the floating chicken intestinal organoids is the combination of a complex cell system with an easily accessible apical-out orientation grown in a simple culture medium without an extracellular matrix. The objective was to investigate the impact of a commercial proprietary blend of organic acids and essential oils (OA+EO) on the innate immune responses and kinome of chicken intestinal organoids in a Salmonella challenge model. To mimic the in vivo prolonged exposure of the intestine to the product, the intestinal organoids were treated for 2 days with 0.5 or 0.25 mg/mL OA+EO and either uninfected or infected with Salmonella and bacterial load in the organoids was quantified at 3 hours post infection. The bacteria were also treated with OA+EO for 1 day prior to challenge of the organoids to mimic intestinal exposure. The treatment of the organoids with OA+EO resulted in a significant decrease in the bacterial load compared to untreated infected organoids. The expression of 88 innate immune genes was investigated using a high throughput qPCR array, measuring the expression of 88 innate immune genes. Salmonella invasion of the untreated intestinal organoids resulted in a significant increase in the expression of inflammatory cytokine and chemokines as well as genes involved in intracellular signaling. In contrast, when the organoids were treated with OA+EO and challenged with Salmonella, the inflammatory responses were significantly downregulated. The kinome array data suggested decreased phosphorylation elicited by the OA+EO with Salmonella in agreement with the gene expression data sets. This study demonstrates that the in vitro chicken intestinal organoids are a new tool to measure the effect of the feed additives in a bacterial challenge model by measuring innate immune and protein kinases responses.

S1PR2 participates in intestinal injury in severe acute pancreatitis by regulating macrophage pyroptosis.

Background: Severe acute pancreatitis (SAP) is an inflammatory disorder affecting the gastrointestinal system. Intestinal injury plays an important role in the treatment of severe acute pancreatitis. In this study, we mainly investigated the role of S1PR2 in regulating macrophage pyroptosis in the intestinal injury of severe acute pancreatitis. Methods: The SAP model was constructed using cerulein and lipopolysaccharide, and the expression of S1PR2 was inhibited by JTE-013 to detect the degree of pancreatitis and intestinal tissue damage in mice. Meanwhile, the level of pyroptosis-related protein was detected by western blot, the level of related mRNA was detected by PCR, and the level of serum inflammatory factors was detected by ELISA. In vitro experiments, LPS+ATP was used to construct the pyroptosis model of THP-1. After knockdown and overexpression of S1PR2, the pyroptosis proteins level was detected by western blot, the related mRNA level was detected by PCR, and the level of cell supernatant inflammatory factors were detected by ELISA. A rescue experiment was used to verify the sufficient necessity of the RhoA/ROCK pathway in S1PR2-induced pyroptosis. Meanwhile, THP-1 and FHC were co-cultured to verify that cytokines released by THP-1 after damage could regulate FHC damage. Results: Our results demonstrated that JTE-013 effectively attenuated intestinal injury and inflammation in mice with SAP. Furthermore, we observed a significant reduction in the expression of pyroptosis-related proteins within the intestinal tissue of SAP mice upon treatment with JTE-013. We confirmed the involvement of S1PR2 in THP-1 cell pyroptosis in vitro. Specifically, activation of S1PR2 triggered pyroptosis in THP-1 cells through the RhoA/ROCK signaling pathway. Moreover, it was observed that inflammatory factors released during THP-1 cell pyroptosis exerted an impact on cohesin expression in FHC cells. Conclusion: The involvement of S1PR2 in SAP-induced intestinal mucosal injury may be attributed to its regulation of macrophage pyroptosis.

Practical diets for California yellowtail, Seriola dorsalis: Use of advanced soybean meal products on growth performance, body composition, intestinal morphology, and immune gene expression.

California yellowtail (CYT), Seriola dorsalis, is a promising candidate for aquaculture due to its rapid growth and high-quality flesh, particularly in markets like Japan, Australia, China, and the United States. Soy protein has shown success as a replacement for marine protein sources in CYT diets, reducing fishmeal levels, though concerns about potential intestinal inflammation persist with the inclusion of solvent-extracted soybean meal. To address this, processing strategies like fractionation, enzymatic treatment, heat treatment, and microbial fermentation have been employed to mitigate the negative impacts of soybean meal on fish nutrition and immune systems. This study focuses on optimizing soybean meal inclusion levels by incorporating advanced soy variants into CYT diets. The eight-week feeding trial, conducted in a recirculation system, featured six diets with sequential inclusion levels (0, 50, 100%) of high protein low oligosaccharide soybean meal (Bright Day, Benson Hill, St Louis, MO) and enzyme-treated soybean meal (HP 300, Hamlet Protein Inc., Findlay, OH), replacing solvent-extracted soybean. The study compares these formulations against a soy-free animal protein-based diet. At the end of the trial, fish were sampled for growth performance, body proximate composition, intestinal morphology, and immune response from gut samples. Results showed consistent FCR (P = 0.775), weight gain (P = 0.242), and high survival rate (99.4 ± 0.5%) among dietary treatments (P>0.05). Histological evaluations revealed no gut inflammation and gene expression analysis demonstrated no significant variations in immune, physiological, and digestive markers apn (P = 0.687), mga (P = 0.397), gpx1 (P = 0.279), atpase (P = 0.590), il1ß (P = 0.659). The study concludes that incorporating advanced soybean meal products, replacing up to 20% of fishmeal does not negatively affect CYT's growth and intestinal health. This suggests that all three soy sources, contributing 35% of total protein (15.4 g 100 g-1 diet), can be included in practical diets without compromising CYT's intestinal integrity or growth. These findings have positive implications for the commercial production of CYT and future research on the incorporation of plant-based proteins in aquaculture diets.

Intestinal cDC1s provide cues required for CD4+ T cell-mediated resistance to Cryptosporidium.

Cryptosporidium is an enteric pathogen and a prominent cause of diarrheal disease worldwide. Control of Cryptosporidium requires CD4+ T cells, but how protective CD4+ T cell responses are generated is poorly understood. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to understand the basis for CD4+ T cell priming and effector function. These studies revealed that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node but differentiate into Th1 cells in the gut to provide local parasite control. Although type 1 conventional dendritic cells (cDC1s) were dispensable for CD4+ T cell priming, they were required for CD4+ T cell gut homing and were a source of IL-12 at the site of infection that promoted local production of IFN-γ. Thus, cDC1s have distinct roles in shaping CD4+ T cell responses to an enteric infection: first, to promote gut homing from the mesLN, and second, to drive effector responses in the intestine.

Cell-Free Supernatant of Bacillus subtilis G2B9-Q Improves Intestinal Health and Modulates Immune Response to Promote Mouse Recovery in Clostridium perfringens Infection.

Clostridium perfringens is one of the critical causative agents causing diarrhea in piglets, with significant economic losses to the pig industry. Under normal gut microbiota homeostasis and well-managed barns, diarrhea caused by C. perfringens could be controlled. Some reports show that probiotics, such as Bacillus subtilis, are beneficial in preventing necrotic enteritis (NE) in chickens, but few reports on piglets. Clostridium perfringens was found in the piglets' diarrhea with intestinal microbiota dysbiosis in our survey. Bacillus subtilis G2B9-Q, which was isolated from the feces of healthy pigs, was found to have anti-Clostridium activity after screening. Clostridium perfringens was used to challenge mice by intraperitoneal injection for modeling to evaluate the anti-infective activity of cell-free supernatant (CFS) of B. subtilis G2B9-Q and different concentrations of B. subtilis G2B9-Q by oral administration. The results showed that G2B9-Q can mitigate intestinal lesions caused by C. perfringens infection, reduce inflammatory reactions, and modulate intestinal microbiota. The CFS of G2B9-Q can alleviate the pathological damage of intestinal tissues caused by C. perfringens infection, reduce the concentration of TNF-α and IL-10 in the sera of mice, as well as the relative expression levels of alpha toxin (CPA), perfringolysin O (PFO) toxin, IL-10, IL-22, and TNF-α in the jejunum and colon tissues, and alleviate the changes in gut microbiota structure caused by C. perfringens infection, which showed better therapeutic effects and indicated that the metabolites of G2B9-Q are essential mediators for their beneficial effects. Therefore, the CFS of G2B9-Q could potentially replace antibiotics in treating C. perfringens infection.

Neuroimmune Interactions in the Intestine.

Recent advances have contributed to a mechanistic understanding of neuroimmune interactions in the intestine and revealed an essential role of this cross talk for gut homeostasis and modulation of inflammatory and infectious intestinal diseases. In this review, we describe the innervation of the intestine by intrinsic and extrinsic neurons and then focus on the bidirectional communication between neurons and immune cells. First, we highlight the contribution of neuronal subtypes to the development of colitis and discuss the different immune and epithelial cell types that are regulated by neurons via the release of neuropeptides and neurotransmitters. Next, we review the role of intestinal inflammation in the development of visceral hypersensitivity and summarize how inflammatory mediators induce peripheral and central sensitization of gut-innervating sensory neurons. Finally, we outline the importance of immune cells and gut microbiota for the survival and function of different neuronal populations at homeostasis and during bacterial and helminth infection.

Comparative studies on the intestinal health of wild and cultured ricefield eel (Monopterus albus).

Fish intestinal health under intensive aquaculture mode plays an important role in growth, development, and immune function. The present study was aimed to systematically investigate the differences of intestinal health between wild and cultured Monopterus albus by biochemical parameters, histomorphology, and molecular biology. A total of 15 healthy M. albus per group, with an average body weight of 45 g, were sampled to analyze intestinal health parameters. Compared with wild fish, the cultured M. albus in the foregut had lower trypsin, lipase, SOD, CAT, T-AOC, and GSH-Px activities (P < 0.05) and higher amylase activity and MDA content (P < 0.05). The villus circumference and goblet cells in the cultured group were significantly lower than those in the wild group (P < 0.05). In addition, the cultured fish showed lower relative expression levels of occludin, zo-1, zo-2, claudin-12, claudin-15, mucin5, mucin15, lysozyme, complement 3, il-10, tgf-ß1, tgf-ß2, and tgf-ß3 (P < 0.05) and higher il-1ß, il-6, il-8, tnf-a, and ifnγ mRNA expressions than those of wild fish (P < 0.05). In terms of gut microbiota, the cultured group at the phylum level displayed higher percentages of Chlamydiae and Spirochaetes and lower percentages of Firmicutes, Bacteroidetes, Actinobacteria, Cyanobacteria, and Verrucomicrobia compared to the wild group (P < 0.05). At the genus level, higher abundances of Pseudomonadaceae_Pseudomonas and Spironema and lower abundances of Lactococcus and Cetobacterium were observed in the cultured group than in the wild group (P < 0.05). To our knowledge, this is the first investigation of the intestinal health status between wild and cultured M. albus in terms of biochemistry, histology, and molecular biology levels. Overall, the present study showed significant differences in intestinal health between wild and cultured M. albus and the main manifestations that wild M. albus had higher intestinal digestion, antioxidant capacity, and intestinal barrier functions than cultured M. albus. These results would provide theoretical basis for the subsequent upgrading of healthy aquaculture technology and nutrient regulation of intestinal health of cultured M. albus.

Crosstalk between CD8+ T cells and mesenchymal stromal cells in intestine homeostasis and immunity.

The intestine represents the most complex cellular network in the whole body. It is constantly faced with multiple types of immunostimulatory agents encompassing from food antigen, gut microbiome, metabolic waste products, and dead cell debris. Within the intestine, most T cells are found in three primary compartments: the organized gut-associated lymphoid tissue, the lamina propria, and the epithelium. The well-orchestrated epithelial-immune-microbial interaction is critically important for the precise immune response. The main role of intestinal mesenchymal stromal cells is to support a structural framework within the gut wall. However, recent evidence from stromal cell studies indicates that they also possess significant immunomodulatory functions, such as maintaining intestinal tolerance via the expression of PDL1/2 and MHC-II molecules, and promoting the development of CD103+ dendritic cells, and IgA+ plasma cells, thereby enhancing intestinal homeostasis. In this review, we will summarize the current understanding of CD8+ T cells and stromal cells alongside the intestinal tract and discuss the reciprocal interactions between T subsets and mesenchymal stromal cell populations. We will focus on how the tissue residency, migration, and function of CD8+ T cells could be potentially regulated by mesenchymal stromal cell populations and explore the molecular mediators, such as TGF-ß, IL-33, and MHC-II molecules that might influence these processes. Finally, we discuss the potential pathophysiological impact of such interaction in intestine hemostasis as well as diseases of inflammation, infection, and malignancies.

T-bet deficiency and Hic1 induction override TGF-ß-dependency in the formation of CD103+ intestine-resident memory CD8+ T cells.

Transforming growth factor ß (TGF-ß) represents a well-established signal required for tissue-resident memory T cell (TRM) formation at intestinal surfaces, regulating the expression of a large collection of genes coordinately promoting intestinal TRM differentiation. The functional contribution from each TGF-ß-controlled transcription factor is not entirely known. Here, we find that TGF-ß-induced T-bet downregulation and Hic1 induction represent two critical events during intestinal TRM differentiation. Importantly, T-bet deficiency significantly rescues intestinal TRM formation in the absence of the TGF-ß receptor. Hic1 induction further strengthens TRM maturation in the absence of TGF-ß and T-bet. Our results reveal that provision of certain TGF-ß-induced molecular events can partially replace TGF-ß signaling to promote the establishment of intestinal TRMs, which allows the functional dissection of TGF-ß-induced transcriptional targets and molecular mechanisms for TRM differentiation.

Association between oral nutrition and inflammation after intestinal transplantation.

Intestinal transplantation (Itx) can be a life-saving treatment for certain patient populations, including those patients with intestinal failure (IF) who develop life-threatening complications due to the use of parenteral nutrition (PN). Most patients who have undergone Itx are eventually able to tolerate a full oral diet. However, little guidance or consensus exists regarding optimizing the specific components of an oral diet for Itx patients, including macronutrients, micronutrients and dietary patterns. While oral dietary prescriptions have moved to the forefront of primary and preventive care, this movement has yet to occur across the field of organ transplantation. Evidence to date points to the role of systemic chronic inflammation (SCI) in a wide variety of chronic diseases as well as post-transplant graft dysfunction. This review will discuss current trends in oral nutrition for Itx patients and also offer novel insights into nutritional management techniques that may help to decrease SCI and chronic disease risk as well as optimize graft function.

Cellular evidence and spatial distribution of endosomal biosynthesis and autophagy in intestinal immune barrier cells of crucian carp (Carassiuscarassius).

Crucian carp (Carassius carassius) is an important aquatic economic animal, and the immune barrier function of its intestine has been a focus of research into oral vaccines and drugs. However, the histological structures of the intestinal barrier and its adjacent areas have not been clearly established, and little subcellular evidence is available to elucidate the spatial distribution of intracellular biological processes. In this study, the spatial distribution of autophagy and endosome formation in the intestinal epithelial cells (IECs) of crucian carp were analyzed. These two biological activities are closely related to intestinal homeostasis, immunity, and cell communication. Periodic acid-Schiff (PAS) and Masson's trichrome staining were employed to elucidate the distinctive histological framework of the Crucian carp's myoid cell network, which resides within the subepithelial layer and is characterized by gap junctions. Transmission electron microscopy (TEM), immunohistochemistry (IHC), and immunofluorescence (IF) were used to detect the structural and functional aspects of the IEC in different intestinal segments. TEM and immunohistochemical analyses captured the biogenesis and maturation of early and late endosomes as well as multivesicular bodies (MVBs), as well as the initiation and progression of autophagy, including macroautophagy and mitophagy. The endosome and MVBs-specific marker CD63 and autophagy-related protein LC3 were highly expressed in IECs and were correlated with autophagy and endosome biosynthesis in the apical and basal regions of individual cells, and differed between different intestinal segments. In summary, this study elucidated the ubiquity and morphological characteristics of autophagy and endosome formation across different intestinal segments of crucian carp. A unique myoid cell network beneath the intestinal epithelium in crucian carp was also identified, expanding the histological understanding of this animal's intestinal tract.

Effects of feeding chicken egg yolk antibodies on intestinal cell apoptosis, oxidative stress and microbial flora of tilapia (Oreochromis niloticus) infected with Streptococcus agalactiae.

Streptococcosis, the most common bacterial disease of fish in recent years, is highly infectious and lethal, and has become an important factor hindering the healthy and sustainable development of aquaculture. Chicken egg yolk antibody (IgY) has the advantages of high antigen specificity, inexpensive and easy to obtain, simple preparation, no toxic side effects, and in line with animal welfare, which is a green and safe alternative to antibiotics. In this study, the potential of specific IgY in the treatment of gastrointestinal pathogens was explored by observing the effects of specific IgY on intestinal flora, pathological tissue, apoptosis, oxidative stress, and inflammatory response of tilapia. We used the specific IgY prepared in the early stage to feed tilapia for 10 days, and then the tilapia was challenged with Streptococcus agalactiae. The results showed that feeding IgY before challenge had a small effect on the intestinal flora, and after challenge specific IgY decreased the proportion of Streptococcus and increased the diversity of the intestinal flora; in histopathology, specific IgY decreased tissue damage and maintained the integrity of tissue structure. Further study found that specific IgY can reduce intestinal epithelial cell apoptosis and reduce caspase activity; at the same time, the content of MDA was decreased, and the activities of SOD, CAT, GSH-Px and GR were increased. In addition, specific IgY can down-regulate the expression levels of IL-8 and TNF-α genes and up-regulate the expression levels of IL-10 and TGF-ß. The results of this study showed that specific IgY could improve the intestinal flora of tilapia infected with Streptococcus agalactiae, reduce intestinal cell apoptosis, oxidative stress injury and inflammatory response, thereby reducing tissue damage and protecting the health of tilapia. Overall, specific IgY can be further explored as a potential antibiotic alternative for gastrointestinal pathogen infections.

Dietary cholesterol intervention could alleviate the intestinal injury of Oreochromis niloticus induced by plant-based diet via the intestinal barriers.

This study aims to explore the effects of supplementing cholesterol in plant-based feed on intestinal barriers (including physical barrier, chemical barrier, immune barrier, biological barrier) of GIFT strain tilapia (Oreochromis niloticus). Four isonitrogenous and isolipidic diets were prepared as follows: plant-based protein diet (Con group) containing corn protein powder, soybean meal, cottonseed meal, and rapeseed meal, with the addition of cholesterol at a level of 0.6 % (C0.6 % group), 1.2 % (C1.2 % group), and 1.8 % (C1.8 % group), respectively. A total of 360 fish (mean initial weight of (6.08 ± 0.12) g) were divided into 12 tanks with 30 fish per tank, each treatment was set with three tanks and the feeding period lasted 9 weeks. Histological analysis revealed that both the C0.6 % and C1.2 % groups exhibited a more organized intestinal structure, with significantly increased muscle layer thickness compared to the Con group (P < 0.05). Furthermore, in the C1.2 % group, there was a significant up-regulation of tight junction-related genes (claudin-14, occludin, zo-1) compared to the Con group (P < 0.05). 5-ethynyl-2'-deoxyuridine staining results also demonstrated a notable enhancement in intestinal cell proliferation within the C1.2 % group (P < 0.05). Regarding the intestinal chemical barrier, trypsin and lipase activities were significantly elevated in the C1.2 % group (P < 0.05), while hepcidin gene expression was considerably down-regulated in this group but up-regulated in the C1.8 % group (P < 0.05). In terms of the intestinal immune barrier, inflammation-related gene expression levels (tnf-α, il-1ß, caspase 9, ire1, perk, atf6) were markedly reduced in the C1.2 % group (P < 0.05). Regarding the intestinal biological barrier, the composition of the intestinal microbiota indicated that compared to the Con group, both the 0.6 % and 1.2 % groups showed a significant increase in Shannon index (P < 0.05). Additionally, there was a significant increase in the abundance of Firmicutes and Clostridium in the C1.2 % group (P < 0.05). In summary, supplementation of 1.2 % cholesterol in the plant-based diet exhibits the potential to enhance intestinal tight junction function and improve the composition of intestinal microbiota, thereby significantly promoting tilapia's intestinal health.

TREM2 deficiency reprograms intestinal macrophages and microbiota to enhance anti-PD-1 tumor immunotherapy.

The gut microbiota and tumor-associated macrophages (TAMs) affect tumor responses to anti-programmed cell death protein 1 (PD-1) immune checkpoint blockade. Reprogramming TAM by either blocking or deleting the macrophage receptor triggering receptor on myeloid cells 2 (TREM2) attenuates tumor growth, and lack of functional TREM2 enhances tumor elimination by anti-PD-1. Here, we found that anti-PD-1 treatment combined with TREM2 deficiency in mice induces proinflammatory programs in intestinal macrophages and a concomitant expansion of Ruminococcus gnavus in the gut microbiota. Gavage of wild-type mice with R. gnavus enhanced anti-PD-1-mediated tumor elimination, recapitulating the effect occurring in the absence of TREM2. A proinflammatory intestinal environment coincided with expansion, increased circulation, and migration of TNF-producing CD4+ T cells to the tumor bed. Thus, TREM2 remotely controls anti-PD-1 immune checkpoint blockade through modulation of the intestinal immune environment and microbiota, with R. gnavus emerging as a potential probiotic agent for increasing responsiveness to anti-PD-1.

Rosmarinic acid mitigates intestinal inflammation and oxidative stress in bullfrogs (Lithobates catesbeiana) fed high soybean meal diets.

High proportions of soybean meal in aquafeed have been confirmed to induce various intestinal pathologies. This study aims to investigate the regulatory effects of rosmarinic acid (RA), an antioxidant with anti-inflammatory and antimicrobial properties, when added to high soybean meal feeds in different doses, (0, 0.5, 1, and 4 g/kg). During the 56-day feeding trial, results indicated that, compared to the control group without RA (0 g/kg), the 1 g/kg and 4 g/kg RA groups increased bullfrog survival rates and total weight gain while reducing feed coefficient. Additionally, these doses markedly suppressed the expression of key intestinal inflammatory markers (tlr5, myd88, tnfα, il1ß, cxcl8, cxcl12) and the activity and content of intestinal antioxidants (CAT, MDA, GSH, GPX). Concurrently, RA significantly downregulated the transcription levels of antioxidant-related genes (cat, gpx5, cyba, cybb, mgst, gclc, gsta, gstp), suggesting RA's potential to alleviate intestinal inflammation and oxidative stress induced by high soybean meal and to help downregulate and restore normal expression of antioxidant enzyme genes. However, the 0.5 g/kg RA group did not show a significant improvement in survival rates; instead, it upregulated the transcription of some antioxidant genes (cat, gpx5, cyba, cybb), revealing the complexity and dose-dependency of RA's antioxidant action. Furthermore, RA supplementation significantly reshaped the intestinal microbial community structure and relative abundance in bullfrogs, particularly affecting the genera Hafnia, Phascolarctobacterium, and Lactococcus. Notably, high doses of RA (1 g/kg, 4 g/kg) were able to downregulate pathways associated with the enrichment of gut microbiota in diseases such as Parkinson's, Staphylococcus aureus infection, and Systemic lupus erythematosus, suggesting its potential in anti-inflammatory action and health maintenance to prevent potential diseases.

Intestinal CXCR6+ ILC3s migrate to the kidney and exacerbate renal fibrosis via IL-23 receptor signaling enhanced by PD-1 expression.

Group 3 innate lymphoid cells (ILC3s) regulate inflammation and tissue repair at mucosal sites, but whether these functions pertain to other tissues-like the kidneys-remains unclear. Here, we observed that renal fibrosis in humans was associated with increased ILC3s in the kidneys and blood. In mice, we showed that CXCR6+ ILC3s rapidly migrated from the intestinal mucosa and accumulated in the kidney via CXCL16 released from the injured tubules. Within the fibrotic kidney, ILC3s increased the expression of programmed cell death-1 (PD-1) and subsequent IL-17A production to directly activate myofibroblasts and fibrotic niche formation. ILC3 expression of PD-1 inhibited IL-23R endocytosis and consequently amplified the JAK2/STAT3/RORγt/IL-17A pathway that was essential for the pro-fibrogenic effect of ILC3s. Thus, we reveal a hitherto unrecognized migration pathway of ILC3s from the intestine to the kidney and the PD-1-dependent function of ILC3s in promoting renal fibrosis.

Winners vs. losers: Schistosoma mansoni intestinal and liver eggs exhibit striking differences in gene expression and immunogenicity.

The eggs of the blood fluke Schistosoma mansoni are the main cause of the clinical manifestations of chronic schistosomiasis. After laying, the egg "winners" attach to the endothelium of the mesenteric vein and, after a period of development, induce the growth of a small granuloma, which facilitates their passage to the intestinal lumen. Egg "losers" carried by the bloodstream to non-specific tissues also undergo full development and induce large granuloma formation, but their life ends there. Although these trapped eggs represent a dead end in the parasite life cycle, the vast majority of studies attempting to describe the biology of the S. mansoni eggs have studied these liver-trapped "losers" instead of migrating intestinal "winners". This raises the fundamental question of how these eggs differ. With robust comparative transcriptomic analysis performed on S. mansoni eggs isolated 7 weeks post infection, we show that gene expression is critically dependent on tissue localization, both in the early and late stages of development. While mitochondrial genes and venom allergen-like proteins are significantly upregulated in mature intestinal eggs, well-described egg immunomodulators IPSE/alpha-1 and omega-1, together with micro-exon genes, are predominantly expressed in liver eggs. In addition, several proteases and protease inhibitors previously implicated in egg-host interactions display clear tissue-specific gene expression patterns. These major differences in gene expression could be then reflected in the observed different ability of liver and intestinal soluble egg antigens to elicit host immune responses and in the shorter viability of miracidia hatched from liver eggs. Our comparative analysis provides a new perspective on the biology of parasite's eggs in the context of their development and tissue localization. These findings could contribute to a broader and more accurate understanding of parasite eggs interactions with the host, which have historically been often restricted to liver eggs and sometimes inaccurately generalized.