Repression of the aryl-hydrocarbon receptor prevents oxidative stress and ferroptosis of intestinal intraepithelial lymphocytes.

The aryl-hydrocarbon receptor (AHR) is a ligand-activated transcription factor that buoys intestinal immune responses. AHR induces its own negative regulator, the AHR repressor (AHRR). Here, we show that AHRR is vital to sustaining intestinal intraepithelial lymphocytes (IELs). AHRR deficiency reduced IEL representation in a cell-intrinsic fashion. Single-cell RNA sequencing revealed an oxidative stress profile in Ahrr-/- IELs. AHRR deficiency unleashed AHR-induced expression of CYP1A1, a monooxygenase that generates reactive oxygen species, increasing redox imbalance, lipid peroxidation, and ferroptosis in Ahrr-/- IELs. Dietary supplementation with selenium or vitamin E to restore redox homeostasis rescued Ahrr-/- IELs. Loss of IELs in Ahrr-/- mice caused susceptibility to Clostridium difficile infection and dextran sodium-sulfate-induced colitis. Inflamed tissue of inflammatory bowel disease patients showed reduced Ahrr expression that may contribute to disease. We conclude that AHR signaling must be tightly regulated to prevent oxidative stress and ferroptosis of IELs and to preserve intestinal immune responses.

Nurturing the phenotype: Environmental signals and transcriptional regulation of intestinal γδ T cells.

The intestinal epithelium harbours a unique lymphocyte population, the intraepithelial lymphocytes (IELs). A large fraction of IELs is represented by γδ T cells. Their role in epithelial homeostasis and immune response is well documented, but a conclusive view of their developmental pathway is still missing. In this review, we discuss the existing literature as well as recent advances regarding the tissue adaptation of γδ IELs, both for the characteristic cytotoxic subset and the newly described noncytotoxic subset. We particularly highlight the environmental cues and the transcriptional regulation that equip γδ T cells with their IEL phenotype.

Extracellular CIRP induces CD4CD8αα intraepithelial lymphocyte cytotoxicity in sepsis.

BACKGROUND: In sepsis, intestinal barrier dysfunction is often caused by the uncontrolled death of intestinal epithelial cells (IECs). CD4CD8αα intraepithelial lymphocytes (IELs), a subtype of CD4+ T cells residing within the intestinal epithelium, exert cytotoxicity by producing granzyme B (GrB) and perforin (Prf). Extracellular cold-inducible RNA-binding protein (eCIRP) is a recently identified alarmin which stimulates TLR4 on immune cells to induce proinflammatory responses. Here, we hypothesized that eCIRP enhances CD4CD8αα IEL cytotoxicity and induces IEC death in sepsis. METHODS: We subjected wild-type (WT) and CIRP-/- mice to sepsis by cecal ligation and puncture (CLP) and collected the small intestines to isolate IELs. The expression of GrB and Prf in CD4CD8αα IELs was assessed by flow cytometry. IELs isolated from WT and TLR4-/- mice were challenged with recombinant mouse CIRP (eCIRP) and assessed the expression of GrB and Prf in CD4CD8αα by flow cytometry. Organoid-derived IECs were co-cultured with eCIRP-treated CD4CD8αα cells in the presence/absence of GrB and Prf inhibitors and assessed IEC death by flow cytometry. RESULTS: We found a significant increase in the expression of GrB and Prf in CD4CD8αα IELs of septic mice compared to sham mice. We found that GrB and Prf levels in CD4CD8αα IELs were increased in the small intestines of WT septic mice, while CD4CD8αα IELs of CIRP-/- mice did not show an increase in those cytotoxic granules after sepsis. We found that eCIRP upregulated GrB and Prf in CD4CD8αα IELs isolated from WT mice but not from TLR4-/- mice. Furthermore, we also revealed that eCIRP-treated CD4CD8αα cells induced organoid-derived IEC death, which was mitigated by GrB and Prf inhibitors. Finally, histological analysis of septic mice revealed that CIRP-/- mice were protected from tissue injury and cell death in the small intestines compared to WT mice. CONCLUSION: In sepsis, the cytotoxicity initiated by the eCIRP/TLR4 axis in CD4CD8αα IELs is associated with intestinal epithelial cell (IEC) death, which could lead to gut injury.

MHC Class I on murine hematopoietic APC selects Type A IEL precursors in the thymus.

TCRαß+ CD8α+ CD8ß- intestinal intraepithelial lymphocytes (CD8αα IEL) are gut T cells that maintain barrier surface homeostasis. Most CD8αα IEL are derived from thymic precursors (IELp) through a mechanism referred to as clonal diversion. In this model, self-reactive thymocytes undergo deletion in the presence of CD28 costimulation, but in its absence undergo diversion to the IEL fate. While previous reports showed that IELp were largely ß2m dependent, the APC that drive the development of these cells are poorly defined. We found that both CD80 and CD86 restrain IELp development, and conventional DCs play a prominent role. We sought to define a CD80/86 negative, MHCI positive APC that supports the development to the IEL lineage. Chimera studies showed that MHCI needs to be expressed on hematopoietic APC for selection. As thymic hematopoietic APC are heterogeneous in their expression of MHCI and costimulatory molecules, we identified four thymic APC types that were CD80/86neg/low and MHCI+ . However, selective depletion of ß2m in individual APC suggested functional redundancy. Thus, while hematopoietic APC play a critical role in clonal diversion, no single APC subset is specialized to promote the CD8αα IEL fate.

Oral typhoid vaccine Ty21a elicits antigen-specific resident memory CD4+ T cells in the human terminal ileum lamina propria and epithelial compartments.

BACKGROUND: Salmonella enterica serovar Typhi (S. Typhi) is a highly invasive bacterium that infects the human intestinal mucosa and causes ~ 11.9-20.6 million infections and ~ 130,000-223,000 deaths annually worldwide. Oral typhoid vaccine Ty21a confers a moderate level of long-lived protection (5-7 years) in the field. New and improved vaccines against enteric pathogens are needed but their development is hindered by a lack of the immunological correlates of protection especially at the site of infection. Tissue resident memory T (TRM) cells provide immediate adaptive effector immune responsiveness at the infection site. However, the mechanism(s) by which S. Typhi induces TRM in the intestinal mucosa are unknown. Here, we focus on the induction of S. Typhi-specific CD4+TRM subsets by Ty21a in the human terminal ileum lamina propria and epithelial compartments. METHODS: Terminal ileum biopsies were obtained from consenting volunteers undergoing routine colonoscopy who were either immunized orally with 4 doses of Ty21a or not. Isolated lamina propria mononuclear cells (LPMC) and intraepithelial lymphocytes (IEL) CD4+TRM immune responses were determined using either S. Typhi-infected or non-infected autologous EBV-B cell lines as stimulator cells. T-CMI was assessed by the production of 4 cytokines [interferon (IFN)γ, interleukin (IL)-2, IL-17A and tumor necrosis factor (TNF)α] in 36 volunteers (18 vaccinees and 18 controls volunteers). RESULTS: Although the frequencies of LPMC CD103+ CD4+TRM were significant decreased, both CD103+ and CD103- CD4+TRM subsets spontaneously produced significantly higher levels of cytokines (IFNγ and IL-17A) following Ty21a-immunization. Importantly, we observed significant increases in S. Typhi-specific LPMC CD103+ CD4+TRM (IFNγ and IL-17A) and CD103- CD4+TRM (IL-2 and IL-17A) responses following Ty21a-immunization. Further, differences in S. Typhi-specific responses between these two CD4+TRM subsets were observed following multifunctional analysis. In addition, we determined the effect of Ty21a-immunization on IEL and observed significant changes in the frequencies of IEL CD103+ (decrease) and CD103- CD4+TRM (increase) following immunization. Finally, we observed that IEL CD103- CD4+TRM, but not CD103+ CD4+TRM, produced increased cytokines (IFNγ, TNFα and IL-17A) to S. Typhi-specific stimulation following Ty21a-immunization. CONCLUSIONS: Oral Ty21a-immunization elicits distinct compartment specific immune responses in CD4+TRM (CD103+ and CD103-) subsets. This study provides novel insights in the generation of local vaccine-specific responses. Trial registration This study was approved by the Institutional Review Board and registered on ClinicalTrials.gov (identifier NCT03970304, Registered 29 May 2019-Retrospectively registered, http://www.ClinicalTrials.gov/NCT03970304).

Shear stress and aneurysms: a review.

Wall shear stress, the frictional force of blood flow tangential to an artery lumen, has been demonstrated in multiple studies to influence aneurysm formation and risk of rupture. In this article, the authors review the ways in which shear stress may influence aneurysm growth and rupture through changes in the vessel wall endothelial cells, smooth-muscle cells, and surrounding adventitia, and they discuss shear stress-induced pathways through which these changes occur.

Role of matrix metalloproteinases in the pathogenesis of intracranial aneurysms.

Intracranial aneurysms (IAs) are a result of complex interactions between biochemical and mechanical forces and can lead to significant morbidity if they rupture and cause subarachnoid hemorrhage. This review explores the role of matrix metalloproteinases (MMPs) in the pathogenesis and progression of IAs. In addition to providing a review of the normal function of MMPs, it is intended to explore the interaction between inflammation and abnormal blood flow and the resultant pathological vascular remodeling processes seen in the development and rupture of IAs. Also reviewed is the potential for the use of MMPs as a diagnostic tool for assessment of aneurysm development and progression.

The biophysical role of hemodynamics in the pathogenesis of cerebral aneurysm formation and rupture.

The pathogenesis of intracranial aneurysms remains complex and multifactorial. While vascular, genetic, and epidemiological factors play a role, nascent aneurysm formation is believed to be induced by hemodynamic forces. Hemodynamic stresses and vascular insults lead to additional aneurysm and vessel remodeling. Advanced imaging techniques allow us to better define the roles of aneurysm and vessel morphology and hemodynamic parameters, such as wall shear stress, oscillatory shear index, and patterns of flow on aneurysm formation, growth, and rupture. While a complete understanding of the interplay between these hemodynamic variables remains elusive, the authors review the efforts that have been made over the past several decades in an attempt to elucidate the physical and biological interactions that govern aneurysm pathophysiology. Furthermore, the current clinical utility of hemodynamics in predicting aneurysm rupture is discussed.

Flow-induced, inflammation-mediated arterial wall remodeling in the formation and progression of intracranial aneurysms.

OBJECTIVE: Unruptured intracranial aneurysms (UIAs) are relatively common lesions that may cause devastating intracranial hemorrhage, thus producing considerable suffering and anxiety in those affected by the disease or an increased likelihood of developing it. Advances in the knowledge of the pathobiology behind intracranial aneurysm (IA) formation, progression, and rupture have led to preclinical testing of drug therapies that would prevent IA formation or progression. In parallel, novel biologically based diagnostic tools to estimate rupture risk are approaching clinical use. Arterial wall remodeling, triggered by flow and intramural stresses and mediated by inflammation, is relevant to both. METHODS: This review discusses the basis of flow-driven vessel remodeling and translates that knowledge to the observations made on the mechanisms of IA initiation and progression on studies using animal models of induced IA formation, study of human IA tissue samples, and study of patient-derived computational fluid dynamics models. RESULTS: Blood flow conditions leading to high wall shear stress (WSS) activate proinflammatory signaling in endothelial cells that recruits macrophages to the site exposed to high WSS, especially through macrophage chemoattractant protein 1 (MCP1). This macrophage infiltration leads to protease expression, which disrupts the internal elastic lamina and collagen matrix, leading to focal outward bulging of the wall and IA initiation. For the IA to grow, collagen remodeling and smooth muscle cell (SMC) proliferation are essential, because the fact that collagen does not distend much prevents the passive dilation of a focal weakness to a sizable IA. Chronic macrophage infiltration of the IA wall promotes this SMC-mediated growth and is a potential target for drug therapy. Once the IA wall grows, it is subjected to changes in wall tension and flow conditions as a result of the change in geometry and has to remodel accordingly to avoid rupture. Flow affects this remodeling process. CONCLUSIONS: Flow triggers an inflammatory reaction that predisposes the arterial wall to IA initiation and growth and affects the associated remodeling of the UIA wall. This chronic inflammation is a putative target for drug therapy that would stabilize UIAs or prevent UIA formation. Moreover, once this coupling between IA wall remodeling and flow is understood, data from patient-specific flow models can be gathered as part of the diagnostic workup and utilized to improve risk assessment for UIA initiation, progression, and eventual rupture.

The progression of coeliac disease: its neurological and psychiatric implications.

The aim of the paper is to show the various neurological and psychiatric symptoms in coeliac disease (CD). CD is a T cell-mediated, tissue-specific autoimmune disease which affects genetically susceptible individuals after dietary exposure to proline- and glutamine-rich proteins contained in certain cereal grains. Genetics, environmental factors and different immune systems, together with the presence of auto-antigens, are taken into account when identifying the pathogenesis of CD. CD pathogenesis is related to immune dysregulation, which involves the gastrointestinal system, and the extra-intestinal systems such as the nervous system, whose neurological symptoms are evidenced in CD patients. A gluten-free diet (GFD) could avoid cerebellar ataxia, epilepsy, neuropathies, migraine and mild cognitive impairment. Furthermore, untreated CD patients have more symptoms and psychiatric co-morbidities than those treated with a GFD. Common psychiatric symptoms in untreated CD adult patients include depression, apathy, anxiety, and irritability and schizophrenia is also common in untreated CD. Several studies show improvement in psychiatric symptoms after the start of a GFD. The present review discusses the state of the art regarding neurological and psychiatric complications in CD and highlights the evidence supporting a role for GFD in reducing neurological and psychiatric complications.

Endovascular management of fusiform aneurysms in the posterior circulation: the era of flow diversion.

Fusiform aneurysms are uncommon compared with their saccular counterparts, yet they remain very challenging to treat and are associated with high rates of rebleeding and morbidity. Lack of a true aneurysm neck renders simple clip reconstruction or coil embolization usually impossible, and more advanced techniques are required, including bypass, stent-assisted coiling, and, more recently, flow diversion. In this article, the authors review posterior circulation fusiform aneurysms, including pathogenesis, natural history, and endovascular treatment, including the role of flow diversion. In addition, the authors propose an algorithm for treatment based on their practice.

Fish oil enhances intestinal barrier function and inhibits corticotropin-releasing hormone/corticotropin-releasing hormone receptor 1 signalling pathway in weaned pigs after lipopolysaccharide challenge.

Stress induces injury in intestinal barrier function in piglets. Long-chain n-3 PUFA have been shown to exhibit potential immunomodulatory and barrier protective effects in animal models and clinical trials. In addition, corticotropin-releasing hormone (CRH)/CRH receptor (CRHR) signalling pathways play an important role in stress-induced alterations of intestinal barrier function. We hypothesised that fish oil could affect intestinal barrier function and CRH/CRHR signalling pathways. In total, thirty-two weaned pigs were allocated to one of four treatments. The experiment consisted of a 2×2 factorial design, and the main factors included immunological challenge (saline or lipopolysaccharide (LPS)) and diet (5 % maize oil or 5 % fish oil). On d 19 of the trial, piglets were treated with saline or LPS. At 4 h after injection, all pigs were killed, and the mesenteric lymph nodes (MLN), liver, spleen and intestinal samples were collected. Fish oil decreased bacterial translocation incidence and the number of translocated micro-organisms in the MLN. Fish oil increased intestinal claudin-1 protein relative concentration and villus height, as well as improved the intestinal morphology. In addition, fish oil supplementation increased intestinal intraepithelial lymphocyte number and prevented elevations in intestinal mast cell and neutrophil numbers induced by LPS challenge. Moreover, fish oil tended to decrease the mRNA expression of intestinal CRHR1, CRH and glucocorticoid receptors. These results suggest that fish oil supplementation improves intestinal barrier function and inhibits CRH/CRHR1 signalling pathway and mast cell tissue density.

Oral delivery of IL-27 recombinant bacteria attenuates immune colitis in mice.

BACKGROUND & AIMS: Treatment of inflammatory bowel disease would benefit from specific targeting of therapeutics to the intestine. We developed a strategy for localized delivery of the immunosuppressive cytokine interleukin (IL)-27, which is synthesized actively in situ by the food-grade bacterium Lactococcus lactis (LL-IL-27), and tested its ability to reduce colitis in mice. METHODS: The 2 genes encoding mouse IL-27 were synthesized with optimal codon use for L lactis and joined with a linker; a signal sequence was added to allow for product secretion. The construct was introduced into L lactis. Colitis was induced via transfer of CD4(+)CD45RB(hi) T cells into Rag(-/-) mice to induce colitis; 7.5 weeks later, LL-IL-27 was administered to mice via gavage. Intestinal tissues were collected and analyzed. RESULTS: LL-IL-27 administration protected mice from T-cell transfer-induced enterocolitis and death. LL-IL-27 reduced disease activity scores, pathology features of large and small bowel, and levels of inflammatory cytokines in colonic tissue. LL-IL-27 also reduced the numbers of CD4(+) and IL-17(+) T cells in gut-associated lymphoid tissue. The effects of LL-IL-27 required production of IL-10 by the transferred T cells. LL-IL-27 was more effective than either LL-IL-10 or systemic administration of recombinant IL-27 in reducing colitis in mice. LL-IL-27 also reduced colitis in mice after administration of dextran sodium sulfate. CONCLUSIONS: LL-IL-27 reduces colitis in mice by increasing the production of IL-10. Mucosal delivery of LL-IL-27 could be a more effective and safer therapy for inflammatory bowel disease.

Modulation of the intestinal microbiota and morphology of tilapia, Oreochromis niloticus, following the application of a multi-species probiotic.

The intestinal microbiota and morphology of tilapia (Oreochromis niloticus) were investigated after the application of a multi-species probiotic containing Lactobacillus reuteri, Bacillus subtilis, Enterococcus faecium and Pediococcus acidilactici (AquaStar(®) Growout). Tilapia (55.03 ± 0.44 g) were fed either a control diet or a probiotic diet (control diet supplemented with AquaStar(®) Growout at 5 g kg(-1)). After four and eight weeks, culture-dependent analysis showed higher levels of lactic acid bacteria (LAB), enterococci and Bacillus spp. in the mucosa and digesta of fish fed AquaStar(®) Growout. At week four, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) revealed a higher similarity within the probiotic fed replicates than replicates of the control group; after eight weeks, the compositional dissimilarity of the microbiome profiles between the groups was greater than the dissimilarities within each group (P < 0.05). High-throughput sequencing revealed that the probiotic treatment significantly reduced the number of operational taxonomic units and species richness in the digesta. Significantly higher proportions of reads belonging to Proteobacteria and Cyanobacteria were detected in the control group whereas the probiotic-fed fish displayed a significantly higher abundance of reads assigned to the Firmicutes (which accounted for >99 % of reads). Bacillus, Cetobacterium and Mycobacterium were the dominant genera in the digesta of control fish whereas Bacillus, Enterococcus and Pediococcus were the largest constituents in probiotic-fed fish. The addition of AquaStar(®) Growout to tilapia diets led to increased populations of intraepithelial leucocytes, a higher absorptive surface area index and higher microvilli density in the intestine. These data suggest that AquaStar(®) Growout can modulate both the intestinal microbiota and morphology of tilapia.

Intraepithelial Lymphogram in the Diagnosis of Celiac Disease in Adult Patients: A Validation Cohort.

BACKGROUND: Celiac disease is a gluten-related pathology, highly prevalent and heterogeneous in its clinical presentation, which leads to delays in diagnosis and misdiagnosis. The analysis of duodenal intraepithelial lymphocytes (IELs) by flow cytometry (lymphogram) is emerging as a discriminative tool in the diagnosis of various forms of celiac disease (CD). AIMS: The aim of this study was to validate IEL lymphogram performance in the largest adult series to our knowledge, in support of its use as a diagnostic tool and as a biomarker of the dynamic celiac process. METHODS: This was a retrospective study including 768 adult patients (217 with active CD, 195 on a gluten-free diet, 15 potential CD patients, and 411 non-celiac controls). The IEL subset cut-off values were established to calculate the diagnostic accuracy of the lymphogram. RESULTS: A complete celiac lymphogram profile (≥14% increase in T cell receptor [TCR]γδ IELs and simultaneous ≤4% decrease in surface-negative CD3 [sCD3-] IELs) was strongly associated with active and potential forms in over 80% of the confirmed patients with CD, whereas the remaining patients with CD had partial lymphogram profiles (≥14% increase in TCRγδ or ≤4% decrease in sCD3- IELs), with lower diagnostic certainty. None of these patients had a non-celiac lymphogram. Quantifying the TCRγδ versus sCD3- imbalance as a ratio (≥5) is a discriminative index to discard or suspect CD at diagnosis. CONCLUSIONS: We have validated the IEL lymphogram's diagnostic efficiency (79% sensitivity, 98% specificity), with an LR+ accuracy of 36.2. As expected, the increase in TCRγδ IELs is a reliable marker for celiac enteropathy, while changes in sCD3- IEL levels throughout the dynamic CD process are useful biomarkers of mucosal lesions.

Glutamine alleviates intestinal injury in a murine burn sepsis model by maintaining intestinal intraepithelial lymphocyte homeostasis.

Intestinal intraepithelial lymphocytes (IELs) play a sentinel role in the mucosal immune system because of their unique anatomical location in the epithelial layer. The disruption of IEL homeostasis is implicated in driving the intestinal injury of many typical inflammatory disorders, such as inflammatory bowel disease (IBD) and sepsis. Therefore, it is meaningful to alleviate intestinal injury by restoring IEL homeostasis in disease conditions. This study explores the effects of glutamine on intestinal IEL homeostasis in a murine model of burn sepsis. We report that glutamine inhibits inflammatory response and reduces injury in the small intestine of burn septic mice. This effect is attributed to the maintaining of IEL homeostasis by suppressing apoptosis and restoring the disrupted subpopulation balance induced by burn sepsis. Mechanistically, we show that glutamine does not affect the IL-15 dependent mechanisms that drive the maintenance and differentiation of IELs. Instead, glutamine sustains IEL homeostasis by upregulate aryl hydrocarbon receptor (AHR) and interleukin (IL)-22 transcription and expression. Consistently, the protective roles of glutamine in burn septic mice were repressed by further supplement with an AHR antagonist CH-223191. Collectively, our study reveals a new role of glutamine to maintain IEL homeostasis by activating the AHR signaling pathway, which in turn ameliorates intestinal injury in burn sepsis.

Commensal bacteria maintain a Qa-1b-restricted unconventional CD8+ T population in gut epithelium.

Intestinal intraepithelial lymphocytes (IELs) are characterized by an unusual phenotype and developmental pathway, yet their specific ligands and functions remain largely unknown. Here by analysis of QFL T cells, a population of CD8+ T cells critical for monitoring the MHC I antigen processing pathway, we established that unconventional Qa-1b-restricted CD8+ T cells are abundant in intestinal epithelium. We found that QFL T cells showed a Qa-1b-dependent unconventional phenotype in the spleen and small intestine of naïve wild-type mice. The splenic QFL T cells showed innate-like functionality exemplified by rapid response to cytokines or antigens, while the gut population was refractory to stimuli. Microbiota was required for the maintenance, but not the initial gut homing of QFL T cells. Moreover, monocolonization with Pediococcus pentosaceus, which expresses a peptide that cross-activated QFL T cells, was sufficient to maintain QFL T cells in the intestine. Thus, microbiota is critical for shaping the Qa-1b-restricted IEL landscape.

Low dietary fiber intake impairs small intestinal Th17 and intraepithelial T cell development over generations.

Dietary fiber strongly impacts the microbiota. Here, we show that a low-fiber diet changes the small intestinal (SI) microbiota and impairs SI Th17, TCRαß+CD8αß+ and TCRαß+CD8αα+ intraepithelial T cell development. We restore T cell development with dietary fiber supplementation, but this defect becomes persistent over generations with constant low-fiber diets. Offspring of low-fiber diet-fed mice have reduced SI T cells even after receiving a fiber-rich diet due to loss of bacteria important for T cell development. In these mice, only a microbiota transplant from a fiber-rich diet-fed mouse and a fiber-rich diet can restore T cell development. Low-fiber diets reduce segmented filamentous bacteria (SFB) abundance, impairing its vertical transmission. SFB colonization and a fiber-rich diet partially restore T cell development. Finally, we observe that low-fiber diet-induced T cell defects render mice more susceptible to Citrobacter rodentium infection. Together, these results demonstrate the importance of fiber to microbiota vertical transmission and host immune system development.

MicroRNA-223 Inhibits Soybean Glycinin- and ß-Conglycinin-Induced Apoptosis of IPEC-J2 Cells by Targeting NLRP-3 in the IEL/IPEC-J2 Co-culture System.

The apoptosis of intestinal porcine epithelial cells induced by soybean antigen protein allergy is one of the most important mechanisms responsible for enteritis. MicroRNAs (miRNAs) affect the cellular and physiological functions of all multicellular organisms. We hypothesize that microRNA-223 inhibits soybean glycinin- and ß-conglycinin-induced apoptosis of intestinal porcine enterocytes (IPEC-J2) by targeting the NLR family pyrin domain containing 3 (NLRP-3). Using the intestinal interepithelial lymphocyte (IEL)/IPEC-J2 co-culture system as an in vitro model, we investigate the role of microRNA-223 in the regulation of soybean glycinin- and ß-conglycinin-induced apoptosis. In co-cultured IEL/IPEC-J2 cells incubated with glycinin or ß-conglycinin, microRNA-223 decreased NLRP-3, ASC, caspase-1, caspase-3, FAS, BCL-2, and APAF-1 expressions in IPEC-J2 cells; decreased cytokine and cyclooxygenase-2 levels; significantly increased cell activity; and inhibited apoptosis. These data supported a novel antiallergic mechanism to mitigate the sensitization of soybean antigenic protein, which involves the upregulation of microRNA-223-targeting NLRP-3.

The promiscuous development of an unconventional Qa1b-restricted T cell population.

MHC-E restricted CD8 T cells show promise in vaccine settings, but their development and specificity remain poorly understood. Here we focus on a CD8 T cell population reactive to a self-peptide (FL9) bound to mouse MHC-E (Qa-1b) that is presented in response to loss of the MHC I processing enzyme ERAAP, termed QFL T cells. We find that mature QFL thymocytes are predominantly CD8αß+CD4-, show signs of agonist selection, and give rise to both CD8αα and CD8αß intraepithelial lymphocytes (IEL), as well as memory phenotype CD8αß T cells. QFL T cells require the MHC I subunit ß-2 microglobulin (ß2m), but do not require Qa1b or classical MHC I for positive selection. However, QFL thymocytes do require Qa1b for agonist selection and full functionality. Our data highlight the relaxed requirements for positive selection of an MHC-E restricted T cell population and suggest a CD8αß+CD4- pathway for development of CD8αα IELs.