Excess Salt Intake Activates IL-21-Dominant Autoimmune Diabetogenesis via a Salt-Regulated Ste20-Related Proline/Alanine-Rich Kinase in CD4 T Cells.

The fundamental mechanisms by which a diet affects susceptibility to or modifies autoimmune diseases are poorly understood. Excess dietary salt intake acts as a risk factor for autoimmune diseases; however, little information exists on the impact of salt intake on type 1 diabetes. To elucidate the potential effect of high salt intake on autoimmune diabetes, nonobese diabetic (NOD) mice were fed a high-salt diet (HSD) or a normal-salt diet (NSD) from 6 to 12 weeks of age and monitored for diabetes development. Our results revealed that the HSD accelerated diabetes progression with more severe insulitis in NOD mice in a CD4+ T-cell-autonomous manner when compared with the NSD group. Moreover, expression of IL-21 and SPAK in splenic CD4+ T cells from HSD-fed mice was significantly upregulated. Accordingly, we generated T-cell-specific SPAK knockout (CKO) NOD mice and demonstrated that SPAK deficiency in T cells significantly attenuated diabetes development in NOD mice by downregulating IL-21 expression in CD4+ T cells. Furthermore, HSD-triggered diabetes acceleration was abolished in HSD-fed SPAK CKO mice when compared with HSD-fed NOD mice, suggesting an essential role of SPAK in salt-exacerbated T-cell pathogenicity. Finally, pharmacological inhibition of SPAK activity using a specific SPAK inhibitor (closantel) in NOD mice ameliorated diabetogenesis, further illuminating the potential of a SPAK-targeting immunotherapeutic approach for autoimmune diabetes. Here, we illustrate that a substantial association between salt sensitivity and the functional impact of SPAK on T-cell pathogenicity is a central player linking high-salt-intake influences to immunopathophysiology of diabetogenesis in NOD mice.

Blimp-1 molds the epigenetic architecture of IL-21-mediated autoimmune diseases through an autoregulatory circuit.

Positive regulatory domain 1 (PRDM1) encodes B lymphocyte-induced maturation protein 1 (BLIMP1), also known as a master regulator of T cell homeostasis. We observed a negative relationship between Blimp-1 and IL-21 based on our previous data that Blimp-1 overexpression in T cells suppresses autoimmune diabetes while Blimp-1-deficient T cells contribute to colitis in NOD mice. Reanalysis of published data sets also revealed an inverse correlation between PRDM1 and IL21 in Crohn's disease. Here, we illustrate that Blimp-1 repressed IL-21 by reducing chromatin accessibility and evicting an IL-21 activator, c-Maf, from the Il21 promoter. Moreover, Blimp-1 overexpression-mediated reduction in permissive chromatin structures at the Il21 promoter could override IL-21-accelerated autoimmune diabetogenesis in small ubiquitin-like modifier-defective c-Maf-transgenic mice. An autoregulatory feedback loop to harness IL-21 expression was unveiled by the evidence that IL-21 addition induced time-dependent Blimp-1 expression and subsequently enriched its binding to the Il21 promoter to suppress IL-21 overproduction. Furthermore, intervention of this feedback loop by IL-21 blockade, with IL-21R.Fc administration or IL-21 receptor deletion, attenuated Blimp-1 deficiency-mediated colitis and reinforced the circuit between Blimp-1 and IL-21 in the regulation of autoimmunity. We highlight the translation of Blimp-1-based epigenetic and transcriptomic profiles applicable to a personalized medicine approach in autoimmune diseases.

Gut Microbiota-Modulated Metabolomic Profiling Shapes the Etiology and Pathogenesis of Autoimmune Diseases.

Autoimmunity is a complex and multifaceted process that contributes to widespread functional decline that affects multiple organs and tissues. The pandemic of autoimmune diseases, which are a global health concern, augments in both the prevalence and incidence of autoimmune diseases, including type 1 diabetes, multiple sclerosis, and rheumatoid arthritis. The development of autoimmune diseases is phenotypically associated with gut microbiota-modulated features at the molecular and cellular levels. The etiology and pathogenesis of autoimmune diseases comprise the alterations of immune systems with the innate and adaptive immune cell infiltration into specific organs and the augmented production of proinflammatory cytokines stimulated by commensal microbiota. However, the relative importance and mechanistic interrelationships between the gut microbial community and the immune system during progression of autoimmune diseases are still not well understood. In this review, we describe studies on the profiling of gut microbial signatures for the modulation of immunological homeostasis in multiple inflammatory diseases, elucidate their critical roles in the etiology and pathogenesis of autoimmune diseases, and discuss the implications of these findings for these disorders. Targeting intestinal microbiome and its metabolomic associations with the phenotype of autoimmunity will enable the progress of developing new therapeutic strategies to counteract microorganism-related immune dysfunction in these autoimmune diseases.

Adipokine-Modulated Immunological Homeostasis Shapes the Pathophysiology of Inflammatory Bowel Disease.

Inflammatory colon diseases, which are a global health concern, include a variety of gastrointestinal tract disorders, such as inflammatory bowel disease and colon cancer. The pathogenesis of these colon disorders involves immune alterations with the pronounced infiltration of innate and adaptive immune cells into the intestines and the augmented expression of mucosal pro-inflammatory cytokines stimulated by commensal microbiota. Epidemiological studies during the past half century have shown that the proportion of obese people in a population is associated with the incidence and pathogenesis of gastrointestinal tract disorders. The advancement of understanding of the immunological basis of colon disease has shown that adipocyte-derived biologically active substances (adipokines) modulate the role of innate and adaptive immune cells in the progress of intestinal inflammation. The biomedical significance in immunological homeostasis of adipokines, including adiponectin, leptin, apelin and resistin, is clear. In this review, we highlight the existing literature on the effect and contribution of adipokines to the regulation of immunological homeostasis in inflammatory colon diseases and discuss their crucial roles in disease etiology and pathogenesis, as well as the implications of these results for new therapies in these disorders.

Post-Translational Modifications of Transcription Factors Harnessing the Etiology and Pathophysiology in Colonic Diseases.

Defects in mucosal immune balance can lead to colonic diseases such as inflammatory bowel diseases and colorectal cancer. With the advancement of understanding for the immunological and molecular basis of colonic disease, therapies targeting transcription factors have become a potential approach for the treatment of colonic disease. To date, the biomedical significance of unique post-translational modifications on transcription factors has been identified, including phosphorylation, methylation, acetylation, ubiquitination, SUMOylation, and O-GlcNAcylation. This review focuses on our current understanding and the emerging evidence of how post-translational regulations modify transcription factors involved in the etiology and pathophysiology of colonic disease as well as the implications of these findings for new therapeutic approaches in these disorders.

Interplay between Cytokine Circuitry and Transcriptional Regulation Shaping Helper T Cell Pathogenicity and Plasticity in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a chronic disorder manifested as Crohn's disease (CD) and ulcerative colitis (UC) characterized by intestinal inflammation and involves a dysregulated immune response against commensal microbiota through the activation of CD4 T helper cells. T helper cell differentiation to effector or regulatory phenotypes is controlled by cytokine networks and transcriptional regulators. Distinct polarized T helper cells are able to alter their phenotypes to adapt to diverse and fluctuating physiological environments. T helper cells exhibit intrinsic instability and flexibility to express cytokines of other lineages or transdifferentiate from one T helper cell type to another in response to various perturbations from physiological cytokine milieu as a means of promoting local immunity in response to injury or ensure tissue homeostasis. Furthermore, functional plasticity and diversity of T helper cells are associated with pathogenicity and are critical for immune homeostasis and prevention of autoimmunity. In this review, we provide deeper insights into the combinatorial extrinsic and intrinsic signals that control plasticity and transdifferentiation of T helper cells and also highlight the potential of exploiting the genetic reprogramming plasticity of T helper cells in the treatment of IBD.

SUMO-defective c-Maf preferentially transactivates Il21 to exacerbate autoimmune diabetes.

SUMOylation is involved in the development of several inflammatory diseases, but the physiological significance of SUMO-modulated c-Maf in autoimmune diabetes is not completely understood. Here, we report that an age-dependent attenuation of c-Maf SUMOylation in CD4+ T cells is positively correlated with the IL-21-mediated diabetogenesis in NOD mice. Using 2 strains of T cell-specific transgenic NOD mice overexpressing wild-type c-Maf (Tg-WTc) or SUMOylation site-mutated c-Maf (Tg-KRc), we demonstrated that Tg-KRc mice developed diabetes more rapidly than Tg-WTc mice in a CD4+ T cell-autonomous manner. Moreover, SUMO-defective c-Maf preferentially transactivated Il21 to promote the development of CD4+ T cells with an extrafollicular helper T cell phenotype and expand the numbers of granzyme B-producing effector/memory CD8+ T cells. Furthermore, SUMO-defective c-Maf selectively inhibited recruitment of Daxx/HDAC2 to the Il21 promoter and enhanced histone acetylation mediated by CREB-binding protein (CBP) and p300. Using pharmacological interference with CBP/p300, we illustrated that CBP30 treatment ameliorated c-Maf-mediated/IL-21-based diabetogenesis. Taken together, our results show that the SUMOylation status of c-Maf has a stronger regulatory effect on IL-21 than the level of c-Maf expression, through an epigenetic mechanism. These findings provide new insights into how SUMOylation modulates the pathogenesis of autoimmune diabetes in a T cell-restricted manner and on the basis of a single transcription factor.

The Modulatory Roles of N-glycans in T-Cell-Mediated Autoimmune Diseases.

Glycosylation is a ubiquitous posttranslational modification of proteins that occurs in the endoplasmic reticulum/Golgi. N-glycans and mucin-type O-glycans are achieved via a series of glycohydrolase- and glycosyltransferase-mediated reactions. Glycosylation modulates immune responses by regulating thymocyte development and T helper cell differentiation. Autoimmune diseases result from an abnormal immune response by self-antigens and subsequently lead to the destruction of the target tissues. The modification of N-glycans has been studied in several animal models of T-cell-mediated autoimmune diseases. This review summarizes and highlights the modulatory effects of N-glycosylation in several autoimmune diseases, including multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, and type 1 diabetes mellitus.

Glucosamine Modulates T Cell Differentiation through Down-regulating N-Linked Glycosylation of CD25.

Glucosamine has immunomodulatory effects on autoimmune diseases. However, the mechanism(s) through which glucosamine modulates different T cell subsets and diseases remain unclear. We demonstrate that glucosamine impedes Th1, Th2, and iTreg but promotes Th17 differentiation through down-regulating N-linked glycosylation of CD25 and subsequently inhibiting its downstream Stat5 signaling in a dose-dependent manner. The effect of glucosamine on T helper cell differentiation was similar to that induced by anti-IL-2 treatment, further supporting an IL-2 signaling-dependent modulation. Interestingly, excess glucose rescued this glucosamine-mediated regulation, suggesting a functional competition between glucose and glucosamine. High-dose glucosamine significantly decreased Glut1 N-glycosylation in Th1-polarized cells. This finding suggests that both down-regulated IL-2 signaling and Glut1-dependent glycolytic metabolism contribute to the inhibition of Th1 differentiation by glucosamine. Finally, glucosamine treatment inhibited Th1 cells in vivo, prolonged the survival of islet grafts in diabetic recipients, and exacerbated the severity of EAE. Taken together, our results indicate that glucosamine interferes with N-glycosylation of CD25, and thereby attenuates IL-2 downstream signaling. These effects suggest that glucosamine may be an important modulator of T cell differentiation and immune homeostasis.

Objective olfactory outcomes after revision endoscopic sinus surgery.

BACKGROUND: Patients who suffer from hyposmia and anosmia report a negative effect on their overall quality of life. Smell disturbance of patients with chronic rhinosinusitis (CRS) can improve after endoscopic sinus surgery (ESS). Although several studies have shown that 50-83% of patients may notice an improvement in olfactory function after ESS, the olfactory improvement after revision ESS (RESS), especially by objective measurements, is still lacking. METHODS: Olfactory function was assessed by the traditional Chinese version of the University of Pennsylvania Smell Identification Test (UPSIT-TC) preoperatively and postoperatively, recorded as smell identification test (SIT) score. Olfactory outcomes from anosmia to hyposmia/normosmia, or from hyposmia to normosmia, were considered as "improvement." Postoperative assessments were divided into two periods: period 1 (P1) is defined as >6 but <12 months postoperatively; period 2 (P2) is defined as >12 but <24 months postoperatively. RESULTS: Thirty-two patients with smell disturbance preoperatively (period 0 [P0]) and confirmed by UPSIT-TC were enrolled into this study. Mean SIT score at P0 was 13.3; mean SIT score at P1 was 18.6; mean SIT score at P2 was 20.4. The presence of nasal polyps blocking the olfactory cleft were associated with better olfaction improvements (p < 0.05) as was the degree of mucosal swelling. The overall improvement rates were 44.8 and 47.8% at P1 and P2, respectively. CONCLUSION: RESS resulted in objective evidence of olfactory improvement in approximately one-half of our cohort over 16 months of follow-up and offers a treatment option for an otherwise poor prognosis condition.

Endoscopic vidian neurectomy assisted by power instrumentation and coblation.

Vidian neurectomy has been used to manage intractable vasomotor rhinitis for decades. After the introduction of endoscopic sinus surgery in the 1980s, transnasal endoscopic vidian neurectomy (EVN) was subsequently reported. The most common problem in performing EVN was excessive bleeding from the pterygopalatine fossa. The complexity and vascularity of the pterygopalatine fossa can cause bloody surgical fields and prevent complete neurectomy. In response to this surgical problem, a procedure was developed to use powered instrumentation and coblation during EVN. There were eight cases of EVNs (16 neurectomies) assisted by power instrumentation and coblation from December 2011 to May 2012. The average blood loss of these cases was 37.5 mL (range, 25-50 mL). The average surgical time of each neurectomy was 27.4 minutes (range, 20-35 minutes). No complications occurred in any of the eight cases. Very limited bleeding and less thermal damage were noted while achieving a complete neurectomy.