Identification of possible candidate genes regulating Sjögren's syndrome-associated autoimmunity: a potential role for TNFSF4 in autoimmune exocrinopathy

Multiomics2Targets identifies targets from cancer cohorts profiled with transcriptomics, proteomics, and phosphoproteomics

The availability of data from profiling of cancer patients with multiomics is rapidly increasing. However, integrative analysis of such data for personalized target identification is not trivial. Multiomics2Targets is a platform that enables users to upload transcriptomics, proteomics, and phosphoproteomics data matrices collected from the same cohort of cancer patients. After uploading the data, Multiomics2Targets produces a report that resembles a research publication. The uploaded matrices are processed, analyzed, and visualized using the tools Enrichr, KEA3, ChEA3, Expression2Kinases, and TargetRanger to identify and prioritize proteins, genes, and transcripts as potential targets. Figures and tables, as well as descriptions of the methods and results, are automatically generated. Reports include an abstract, introduction, methods, results, discussion, conclusions, and references and are exportable as citable PDFs and Jupyter Notebooks. Multiomics2Targets is applied to analyze version 3 of the Clinical Proteomic Tumor Analysis Consortium (CPTAC3) pan-cancer cohort, identifying potential targets for each CPTAC3 cancer subtype. Multiomics2Targets is available from https://multiomics2targets.maayanlab.cloud/.

A MZB Cell Activation Profile Present in the Lacrimal Glands of Sjögren's Syndrome-Susceptible C57BL/6.NOD-Aec1Aec2 Mice Defined by Global RNA Transcriptomic Analyses

The C57BL/6.NOD-Aec1Aec2 mouse has been extensively studied to define the underlying cellular and molecular basis for the onset and development of Sjögren's syndrome (SS), a human systemic autoimmune disease characterized clinically as the loss of normal lacrimal and salivary gland functions leading respectively to dry eye and dry mouth pathologies. While an overwhelming majority of SS studies in both humans and rodent models have long focused primarily on pathophysiological events and the potential role of T lymphocytes in these events, recent studies in our murine models have indicated that marginal zone B (MZB) lymphocytes are critical for both development and onset of SS disease. Although migration and function of MZB cells are difficult to study in vivo and in vitro, we have carried out ex vivo investigations that use temporal global RNA transcriptomic analyses to track early cellular and molecular events in these exocrine glands of C57BL/6.NOD-Aec1Aec2 mice. In the present report, genome-wide transcriptome analyses of lacrimal glands indicate that genes and gene-sets temporally upregulated during early onset of disease define the Notch2/NF-kβ14 and Type1 interferon signal transduction pathways, as well as identify chemokines, especially Cxcl13, and Rho-GTPases, including DOCK molecules, in the cellular migration of immune cells to the lacrimal glands. We discuss how the current results compare with our recently published salivary gland data obtained from similar studies carried out in our C57BL/6.NOD-Aec1Aec2 mice, pointing out both similarities and differences in the etiopathogeneses underlying the autoimmune response within the two glands. Overall, this study uses the power of transcriptomic analyses to identify temporal molecular bioprocesses activated during the preclinical covert pathogenic stage(s) of SS disease and how these findings may impact future intervention therapies as the disease within the two exocrine glands may not be identical.

Upregulated Chemokine and Rho-GTPase Genes Define Immune Cell Emigration into Salivary Glands of Sjögren's Syndrome-Susceptible C57BL/6.NOD-Aec1Aec2 Mice

The C57BL/6.NOD-Aec1Aec2 mouse is considered a highly appropriate model of Sjögren's Syndrome (SS), a human systemic autoimmune disease characterized primarily as the loss of lacrimal and salivary gland functions. This mouse model, as well as other mouse models of SS, have shown that B lymphocytes are essential for the development and onset of observed clinical manifestations. More recently, studies carried out in the C57BL/6.IL14α transgenic mouse have indicated that the marginal zone B (MZB) cell population is responsible for development of SS disease, reflecting recent observations that MZB cells are present in the salivary glands of SS patients and most likely initiate the subsequent loss of exocrine functions. Although MZB cells are difficult to study in vivo and in vitro, we have carried out an ex vivo investigation that uses temporal global RNA transcriptomic analyses to profile differentially expressed genes known to be associated with cell migration. Results indicate a temporal upregulation of specific chemokine, chemokine receptor, and Rho-GTPase genes in the salivary glands of C57BL/6.NOD-Aec1Aec2 mice that correlate with the early appearance of periductal lymphocyte infiltrations. Using the power of transcriptomic analyses to better define the genetic profile of lymphocytic emigration into the salivary glands of SS mice, new insights into the underlying mechanisms of SS disease development and onset begin to come into focus, thereby establishing a foundation for further in-depth and novel investigations of the covert and early overt phases of SS disease at the cellular level.

GPA33 is expressed on multiple human blood cell types and distinguishes CD4+ central memory T cells with and without effector function

The Ig superfamily protein glycoprotein A33 (GPA33) has been implicated in immune dysregulation, but little is known about its expression in the immune compartment. Here, we comprehensively determined GPA33 expression patterns on human blood leukocyte subsets, using mass and flow cytometry. We found that GPA33 was expressed on fractions of B, dendritic, natural killer and innate lymphoid cells. Most prominent expression was found in the CD4⁺ T cell compartment. Naïve and CXCR5⁺ regulatory T cells were GPA33^high, and naïve conventional CD4⁺ T cells expressed intermediate GPA33 levels. The expression pattern of GPA33 identified functional heterogeneity within the CD4⁺ central memory T cell (Tcm) population. GPA33⁺ CD4⁺ Tcm cells were fully undifferentiated, bona fide Tcm cells that lack immediate effector function, whereas GPA33^– Tcm cells exhibited rapid effector functions and may represent an early stage of differentiation into effector/effector memory T cells before loss of CD62L. Expression of GPA33 in conventional CD4⁺ T cells suggests a role in localization and/or preservation of an undifferentiated state. These results form a basis to study the function of GPA33 and show it to be a useful marker to discriminate between different cellular subsets, especially in the CD4⁺ T cell lineage.

Clinical evaluation of germline polymorphisms associated with capecitabine toxicity in breast cancer: TBCRC-015

PURPOSE

Capecitabine is important in breast cancer treatment but causes diarrhea and hand-foot syndrome (HFS), affecting adherence and quality of life. We sought to identify pharmacogenomic predictors of capecitabine toxicity using a novel monitoring tool.

METHODS

Patients with metastatic breast cancer were prospectively treated with capecitabine (2000 mg/m²/day, 14 days on/7 off). Patients completed in-person toxicity questionnaires (day 1/cycle) and automated phone-in assessments (days 8, 15). Correlation of genotypes with early and overall toxicity was the primary endpoint.

RESULTS

Two hundred and fifty-nine patients were enrolled (14 institutions). Diarrhea and HFS occurred in 52% (17% grade 3) and 69% (9% grade 3), respectively. Only 29% of patients completed four cycles without dose reduction/interruption. In 39%, the highest toxicity grade was captured via phone. Three single nucleotide polymorphisms (SNPs) associated with diarrhea-DPYD*5 (odds ratio [OR] 4.9; P = 0.0005), a MTHFR missense SNP (OR 3.3; P = 0.02), and a SNP upstream of MTRR (OR 3.0; P = 0.03). GWAS elucidated a novel HFS SNP (OR 3.0; P = 0.0007) near TNFSF4 (OX40L), a gene implicated in autoimmunity including autoimmune skin diseases never before implicated in HFS. Genotype-gene expression analyses of skin tissues identified rs11158568 (associated with HFS via GWAS) with expression of CHURC1, a transcriptional activator controlling fibroblast growth factor (beta = - 0.74; P = 1.46 × 10^-23), representing a previously unidentified mechanism for HFS.

CONCLUSIONS

This is the first cancer pharmacogenomic study to use phone-in self-reporting, permitting augmented toxicity characterization. Three germline toxicity SNPs were replicated, and several novel SNPs/genes having strong functional relevance were discovered. If further validated, these markers could permit personalized capecitabine dosing.

Epidermal Fatty Acid-Binding Protein: A Novel Marker in the Diagnosis of Dry Eye Disease in Sjögren Syndrome

Purpose: Sjögren syndrome (SS) is a chronic inflammatory autoimmune disease of the lacrimal and salivary glands. This study compared the concentrations of epidermal fatty-acid binding protein (E-FABP) in the saliva, serum, and tears of SS patients with dry eye and dry mouth, with those of healthy adults to investigate the usefulness of E-FABP as a diagnostic marker for SS. Design: Prospective, observational case series. Participants: The subjects were 11 new patients with untreated Sjogren syndrome and 12 healthy control individuals. Methods: The diagnosis of SS was in accordance with the Ministry of Health, Labour and Welfare (Japan) Diagnostic Criteria (1999). Saliva, serum, and tear specimens were collected during internal medicine, dental, and ophthalmological examinations. The ophthalmological tests included the Dry Eye-related Quality of life Score (DEQS), tear break-up time (BUT), vital staining with fluorescein (FS) and lissamine green (LG), and the Schirmer test-1. The E-FABP concentration in the tears, saliva, and serum was measured by enzyme-linked immunosorbent assay (ELISA). Main outcome measure: The E-FABP concentrations were compared between patients and controls. Results: There were significant differences between the patient and healthy control groups in all ophthalmological test results. There were no significant differences between the groups in the E-FABP concentrations in the saliva (p = 0.1513) or the serum (p = 0.4799), but the E-FABP concentration in the tears significantly differed between groups. The E-FABP concentration in tears tended to be significantly lower in patients with SS (mean, 323.5 ± 325.6 pg/mL) than healthy control subjects (mean, 4076 pg/mL; p = 0.0136). The E-FABP concentration in tears significantly correlated with the results of dry eye parameters. Conclusion: The E-FABP concentration in tears appears to be related to ocular surface epithelial damage and tear stability and may be a promising novel biomarker in the diagnosis of SS.

Pathological Analysis of Ocular Lesions in a Murine Model of Sjögren's Syndrome

Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by severe inflammation of exocrine glands such as the salivary and lacrimal glands. When it affects the lacrimal glands, many patients experience keratoconjunctivitis due to severely dry eyes. This study investigated the pathological and immunological characteristics of ocular lesions in a mouse model of SS. Corneal epithelial injury and hyperplasia were confirmed pathologically. The number of conjunctival mucin-producing goblet cells was significantly decreased in the SS model mice compared with control mice. Expression levels of transforming growth factor (TGF)-β, interleukin (IL)-6, tumor necrosis factor (TNF)-α, and C-X-C motif chemokine (CXCL) 12 were significantly higher in the corneal epithelium of the SS model mice than in control mice. Inflammatory lesions were observed in the Harderian, intraorbital, and extraorbital lacrimal glands in the SS model mice, suggesting that the ocular glands were targeted by an autoimmune response. The lacrimal glands of the SS model mice were infiltrated by cluster of differentiation (CD)4⁺ T cells. Real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed significantly increased mRNA expression of TNF-α, TGF-β, CXCL9, and lysozyme in the extraorbital lacrimal glands of the SS model mice compared with control mice. These results add to the understanding of the complex pathogenesis of SS and may facilitate development of new therapeutic strategies.

What can Sjögren's syndrome-like disease in mice contribute to human Sjögren's syndrome?

For decades, Sjögren's syndrome (SS) and Sjögren's syndrome-like (SS-like) disease in patients and mouse models, respectively, have been intensely investigated in attempts to identify the underlying etiologies, the pathophysiological changes defining disease phenotypes, the nature of the autoimmune responses, and the propensity for developing B cell lymphomas. An emerging question is whether the generation of a multitude of mouse models and the data obtained from their studies is actually important to the understanding of the human disease and potential interventional therapies. In this brief report, we comment on how and why mouse models can stimulate interest in specific lines of research that apparently parallel aspects of human SS. Focusing on two mouse models, NOD and B6·Il14α, we present the possible relevance of mouse models to human SS, highlighting a few selected disease-associated biological processes that have baffled both SS and SS-like investigations for decades.

Age-related Defects in Ocular and Nasal Mucosal Immune System and the Immunopathology of Dry Eye Disease

Dry eye disease (DED) is a prevalent public health concern that affects up to 30% of adults and is particularly chronic and severe in the elderly. Two interconnected mechanisms cause DED: (1) an age-related dysfunction of lacrimal and meibomian glands, which leads to decreased tear production and/or an increase in tear evaporation; and (2) an age-related uncontrolled inflammation of the surface of the eye triggered by yet-to-be-determined internal immunopathological mechanisms, independent of tear deficiency and evaporation. In this review we summarize current knowledge on animal models that mimic both the severity and chronicity of inflammatory DED and that have been reliably used to provide insights into the immunopathological mechanisms of DED, and we provide an overview of the opportunities and limitations of the rabbit model in investigating the role of both ocular and nasal mucosal immune systems in the immunopathology of inflammatory DED and in testing novel immunotherapies aimed at delaying or reversing the uncontrolled age-related inflammatory DED.

Glycoprotein A33 deficiency: a new mouse model of impaired intestinal epithelial barrier function and inflammatory disease

The cells of the intestinal epithelium provide a selectively permeable barrier between the external environment and internal tissues. The integrity of this barrier is maintained by tight junctions, specialised cell-cell contacts that permit the absorption of water and nutrients while excluding microbes, toxins and dietary antigens. Impairment of intestinal barrier function contributes to multiple gastrointestinal disorders, including food hypersensitivity, inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). Glycoprotein A33 (GPA33) is an intestinal epithelium-specific cell surface marker and member of the CTX group of transmembrane proteins. Roles in cell-cell adhesion have been demonstrated for multiple CTX family members, suggesting a similar function for GPA33 within the gastrointestinal tract. To test a potential requirement for GPA33 in intestinal barrier function, we generated Gpa33^−/− mice and subjected them to experimental regimens designed to produce food hypersensitivity, colitis and CAC. Gpa33^−/− mice exhibited impaired intestinal barrier function. This was shown by elevated steady-state immunosurveillance in the colonic mucosa and leakiness to oral TRITC-labelled dextran after short-term exposure to dextran sodium sulphate (DSS) to injure the intestinal epithelium. Gpa33^−/− mice also exhibited rapid onset and reduced resolution of DSS-induced colitis, and a striking increase in the number of colitis-associated tumours produced by treatment with the colon-specific mutagen azoxymethane (AOM) followed by two cycles of DSS. In contrast, Gpa33^−/− mice treated with AOM alone showed no increase in sporadic tumour formation, indicating that their increased tumour susceptibility is dependent on inflammatory stimuli. Finally, Gpa33^−/− mice displayed hypersensitivity to food allergens, a common co-morbidity in humans with IBD. We propose that Gpa33^−/− mice provide a valuable model to study the mechanisms linking intestinal permeability and multiple inflammatory pathologies. Moreover, this model could facilitate preclinical studies aimed at identifying drugs that restore barrier function.

Highlighted Article: We show that GPA33, an intestine-specific cell surface protein, plays a role in the maintenance of intestinal barrier function and the prevention of intestinal pathologies such as food hypersensitivity, inflammatory bowel disease and colitis-associated cancer.

Monocytes from Sjögren's syndrome patients display increased vasoactive intestinal peptide receptor 2 expression and impaired apoptotic cell phagocytosis

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by salivary and lacrimal gland dysfunction. Clinical observations and results from animal models of SS support the role of aberrant epithelial cell apoptosis and immune homeostasis loss in the glands as triggering factors for the autoimmune response. Vasoactive intestinal peptide (VIP) promotes potent anti-inflammatory effects in several inflammatory and autoimmune disease models, including the non-obese diabetic (NOD) mouse model of SS. With the knowledge that VIP modulates monocyte function through vasoactive intestinal peptide receptors (VPAC) and that immune homeostasis maintenance depends strongly upon a rapid and immunosuppressant apoptotic cell clearance by monocytes/macrophages, in this study we explored VPAC expression on monocytes from primary SS (pSS) patients and the ability of VIP to modulate apoptotic cell phagocytic function and cytokine profile. Monocytes isolated from individual pSS patients showed an increased expression of VPAC2 subtype of VIP receptors, absent in monocytes from control subjects, with no changes in VPAC1 expression. VPAC2 receptor expression could be induced further with lipopolysaccharide (LPS) in pSS monocytes and VIP inhibited the effect. Moreover, monocytes from pSS patients showed an impaired phagocytosis of apoptotic epithelial cells, as evidenced by reduced engulfment ability and the failure to promote an immunosuppressant cytokine profile. However, VIP neither modulated monocyte/macrophage phagocytic function nor did it reverse their inflammatory profile. We conclude that monocytes from pSS patients express high levels of VPAC2 and display a deficient clearance of apoptotic cells that is not modulated by VIP.

Pathogenetic role of an autoimmune susceptibility locus derived from MRL/MpJ strain chromosome 1 in chronic pancreas inflammation

We examined the role of Mag, an autoimmune susceptibility locus encoded by the telomeric region of MRL/MpJ mouse chromosome 1, in the pathogenesis of autoimmune exocrinopathy. At nine to 12 months of age, strain-specific differences were observed in the pancreas of the animals. B- and T-cell-containing periductal/perivascular cell infiltrations in the pancreases of MRL/MpJ and B6.MRLc1 congenic C57BL/6-background Mag-carrying strains were more severe than were those of C57BL/6. Pancreatic periductal/perivascular cell infiltration was observed frequently in A/J, AKR/N, B6.MRLc1, C57BL/6, and MRL/MpJ, moderately in DBA/1 and DBA/2, and rarely in BALB/c and C3H/He strains. Females tended to have greater pancreatic periductal/perivascular cell infiltration than males. C57BL/6 mice possessed defined borders between cell infiltrations and acini, but borders were indistinct in MRL/MpJ and B6.MRLc1 mice. We attributed this to the invasion of inflammatory cells between each acinus and the disruption of acinar cells around cell infiltrations in the latter strains. No strain-specific differences were observed in the appearance of fibrotic lesions and high endothelial venules in the cell infiltrates. The levels of serum anti-dsDNA antibodies and amylase, and mRNA expression of tumor necrosis factor-α and Fc gamma receptor III (encoded on Mag) in the pancreases, were elevated in MRL/MpJ- and B6.MRLc1-strain mice relative to C57BL/6. These results emphasized the crucial roles of Mag in the molecular and genetic pathogenesis of autoimmune-mediated pancreatitis.

The value of animal models to study immunopathology of primary human Sjögren's syndrome symptoms

Sjögren's syndrome (SjS) is a complex chronic autoimmune disease of multifactorial etiology that results in eventual loss of secretory function in the exocrine glands. The challenges towards finding a therapeutic prevention or treatment for SjS are due primarily to a lack of understanding in the pathophysiological and clinical progression of the disease. In order to circumnavigate this problem, there is a need for appropriate animal models that resemble the major phenotypes of human SjS and deliver a clear underlying biological or molecular mechanism capable of defining various aspects for the disease. Here, we present an overview of SjS mouse models that are providing insight into the autoimmune process of SjS and advance our focus on potential diagnostic and therapeutic targets.

Candidate chromosome 1 disease susceptibility genes for Sjogren's syndrome xerostomia are narrowed by novel NOD.B10 congenic mice

Sjogren's syndrome (SS) is characterized by salivary gland leukocytic infiltrates and impaired salivation (xerostomia). Cox-2 (Ptgs2) is located on chromosome 1 within the span of the Aec2 region. In an attempt to demonstrate that COX-2 drives antibody-dependent hyposalivation, NOD.B10 congenic mice bearing a Cox-2flox gene were generated. A congenic line with non-NOD alleles in Cox-2-flanking genes failed manifest xerostomia. Further backcrossing yielded disease-susceptible NOD.B10 Cox-2flox lines; fine genetic mapping determined that critical Aec2 genes lie within a 1.56 to 2.17Mb span of DNA downstream of Cox-2. Bioinformatics analysis revealed that susceptible and non-susceptible lines exhibit non-synonymous coding SNPs in 8 protein-encoding genes of this region, thereby better delineating candidate Aec2 alleles needed for SS xerostomia.

Interstitial lung diseases-can pathologists arrive at an etiology-based diagnosis? A critical update

Interstitial lung diseases (ILD) encompass a group of diseases with a wide range of etiologies and a variety of tissue reactions within the lung. In many instances, a careful evaluation of the tissue reactions will result in a specific diagnosis or at least in a narrow range of differentials, which will assist the clinician to arrive at a definite diagnosis, when combining our interpretation with the clinical presentation of the patient and high-resolution computed tomography. In this review, we will exclude granulomatous pneumonias as well as vascular diseases (primary arterial pulmonary hypertension and vasculitis); however, pulmonary hypertension as a complication of interstitial processes will be mentioned. Few entities of pneumoconiosis presenting as an interstitial process will be included, whereas those with granulomatous reactions will be excluded. Drug reactions will be touched on within interstitial pneumonias, but will not be a major focus. In contrast to the present-day preferred descriptive pattern recognition, it is the author's strong belief that pathologists should always try to dig out the etiology from a tissue specimen and not being satisfied with just a pattern description. It is the difference of sorting tissue reactions into boxes by their main pattern, without recognizing minor or minute reactions, which sometimes will guide one to the correct etiology-oriented interpretation. In the author's personal perspective, tissue reactions can even be sorted by their timeliness, and therefore, ordered by the time of appearance, providing an insight into the pathogenesis and course of a disease. Also, underlying immune mechanisms will be discussed briefly as far as they are essential to understand the disease.

Vasoactive intestinal peptide/vasoactive intestinal peptide receptor relative expression in salivary glands as one endogenous modulator of acinar cell apoptosis in a murine model of Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by a progressive oral and ocular dryness that correlates poorly with the autoimmune damage of the glands. It has been proposed that a loss of homeostatic equilibrium in the glands is partly responsible for salivary dysfunction with acinar cells involved actively in the pathogenesis of SS. The non-obese diabetic (NOD) mouse model of Sjögren's syndrome develops secretory dysfunction and early loss of glandular homeostatic mechanisms, with mild infiltration of the glands. Based on the vasodilator, prosecretory and trophic effects of the vasoactive intestinal peptide (VIP) on acini as well as its anti-inflammatory properties we hypothesized that the local expression of VIP/vasoactive intestinal peptide receptor (VPAC) system in salivary glands could have a role in acinar cell apoptosis and macrophage function thus influencing gland homeostasis. Here we show a progressive decline of VIP expression in submandibular glands of NOD mice with no changes in VPAC receptor expression compared with normal mice. The deep loss of endogenous VIP was associated with a loss of acinar cells through apoptotic mechanisms that could be induced further by tumour necrosis factor (TNF)-α and reversed by VIP through a cyclic adenosine-5'-monophosphate (cAMP)/protein kinase A (PKA)-mediated pathway. The clearance of apoptotic acinar cells by macrophages was impaired for NOD macrophages but a shift from inflammatory to regulatory phenotype was induced in macrophages during phagocytosis of apoptotic acinar cells. These results support that the decline in endogenous VIP/VPAC local levels might influence the survival/apoptosis intracellular set point in NOD acinar cells and their clearance, thus contributing to gland homeostasis loss.

Sjögren's syndrome: studying the disease in mice

Sjögren's syndrome (SS), a systemic autoimmune disease, is characterized by inflammation of exocrine tissues accompanied by a significant loss of their secretory function. Clinical symptoms develop late and there are no diagnostic tests enabling early diagnosis of SS. Thus, particularly to study these covert stages, researchers turn to studying animal models where mice provide great freedom for genetic manipulation and testing the effect of experimental intervention. The present review summarizes current literature pertaining to both spontaneous and extrinsic-factor induced SS-like diseases in mouse models, discussing advantages and disadvantages related to the use of murine models in SS research.

Defective feedback regulation of NF-kappaB underlies Sjogren's syndrome in mice with mutated kappaB enhancers of the IkappaBalpha promoter

Feedback regulation of transcription factor NF-kappaB by its inhibitor IkappaBalpha plays an essential role in control of NF-kappaB activity. To understand the biological significance of IkappaBalpha-mediated feedback regulation of NF-kappaB, we generated mice harboring mutated kappaB enhancers in the promoter of the IkappaBalpha gene (IkappaBalpha(M/M)) to inhibit NF-kappaB-regulated IkappaBalpha expression. Here, we report that these mutant mice are defective in NF-kappaB-induced expression of IkappaBalpha. This defective feedback regulation of NF-kappaB by IkappaBalpha not only altered activity of NF-kappaB, but also the expression of NF-kappaB-regulated genes. As a result, IkappaBalpha(M/M), the homozygous knock-in mice with mutated kappaB enhancers in the IkappaBalpha promoter, acquire shorten life span, hypersensitivity to septic shock, abnormal T-cell development and activation, and Sjögren's Syndrome. These findings therefore demonstrate that the IkappaBalpha-mediated feedback regulation of NF-kappaB has an essential role in controlling T-cell development and functions, provide mechanistic insight into the development of Sjögren's Syndrome, and suggest the potential of NF-kappaB signaling as a therapeutic target for Sjögren's Syndrome and other autoimmune diseases.

Differential gene expression in the salivary gland during development and onset of xerostomia in Sjögren's syndrome-like disease of the C57BL/6.NOD-Aec1Aec2 mouse

INTRODUCTION

Recently, we reported the development of the C57BL/6.NOD-Aec1Aec2 mouse that carries two genetic intervals derived from the non-obese diabetic (NOD) mouse capable of conferring Sjögren's syndrome (SjS)-like disease in SjS-non-susceptible C57BL/6 mice. In an attempt to define the molecular bases underlying the onset of stomatitis sicca (xerostomia) in this C57BL/6.NOD-Aec1Aec2 mouse model, we have carried out a study using genomic microarray technology.

METHODS

By means of oligonucleotide microarrays, gene expression profiles of salivary glands at 4, 8, 12, 16, and 20 weeks of age were generated for C57BL/6.NOD-Aec1Aec2 male mice. Using Linear Models for Microarray Analysis and B-statistics software, 480 genes were identified as being differentially expressed (P < 0.01 and Q < 0.0001) during the development of SjS-like disease in the salivary glands.

RESULTS

The 480 genes could be arranged into four clusters, with each cluster defining a unique pattern of temporal expression, while the individual genes within each cluster could be grouped according to related biological functions. By means of pair-wise analysis, temporal changes in transcript expressions provided profiles indicating that many additional genes are differentially expressed at specific time points during the development of disease. Multiple genes reportedly showing an association with autoimmunity and/or SjS, in either humans or mouse models, were found to exhibit differential expressions, both quantitatively and temporally. Selecting various families of genes associated with specific functions (for example, antibody production, complement, and chemokines), we noted that only a limited number of family members showed differential expressions and these correlated with specific phases of disease.

CONCLUSIONS

Taking advantage of known functions of these genes, investigators can construct interactive gene pathways, leading to modeling of possible underlying events inducing salivary gland dysfunction. Thus, these different approaches to analyzing microarray data permit the identification of multiple sets of genes of interest whose expressions and expression profiles may correlate with molecular mechanisms, signaling pathways, and/or immunological processes involved in the development and onset of SjS.

Vasoactive intestinal peptide inhibits TNF-alpha-induced apoptotic events in acinar cells from nonobese diabetic mice submandibular glands

Introduction

The role of apoptotic secretory epithelium as a pro-inflammatory triggering factor of exocrine dysfunction is currently explored in Sjogren's syndrome patients and in the nonobese diabetic (NOD) mouse model. Vasoactive intestinal peptide (VIP) has anti-inflammatory effects in various models of chronic inflammation. Our goal was to analyse the effect of TNF-α on apoptotic mediators in isolated acinar cells from NOD submandibular gland and their modulation by VIP.

Methods

Acinar cells were isolated from submandibular glands of 16-week-old NOD females with salivary flow decline. Age-matched BALB/c females or eight-week-old NOD females were used as controls. Apoptotic mediators and TNF-α receptor expression were assessed by immunoblotting and RT-PCR, caspase 3 activity was assessed by optical density at 405 nm with Ac-DEVD-pNA as a substrate and chromatin condensation by Hoechst stain. They were evaluated in resting conditions and after a 3.5 or 6 hours of culture with TNF-α. VIP effects in acinar cells were assessed at 100 nM in TNF-α-treated cultures and VIP receptor functional assays by radio immunoassay (cAMP) or enzymatic detection (amylase).

Results

NOD acinar cells at 16 weeks present an increased expression of TNF-α receptor1 together with increased Bax, tumour protein 53-induced nuclear protein1α (TP53INP1α), caspase 3 activity and chromatin condensation. Acini from NOD mice were more sensitive to TNF-α-induced increases of apoptotic mediators than control cells. VIP inhibited TNF-α-induced apoptotic events through functional VPAC1 receptors coupled to the protein kinase A (PKA) signalling pathway.

Conclusions

Our results indicate that acinar cells isolated from submandibular glands of NOD mice with salivary dysfunction are more sensitive to apoptosis induced by TNF-α which could be prevented by VIP through a PKA-mediated pathway.

Sjögren's syndrome: an old tale with a new twist

Sjögren's syndrome (SjS) is chronic autoimmune disease manifested by the loss of saliva and/or tear secretion by salivary and/or lacrimal glands, respectively. The pathogenesis of the disease remains elusive, perhaps due to the multiple triggers of the disease. However, substantial advances have been made in attempting to resolve the complexity of SjS using both animal models and human subjects. The primary objectives of this review are to provide a better understanding of the disease processes with major emphasis on the use of mouse models, how genetic predisposition plays a role in the natural history of the disease, as well as a presentation of new findings pertaining to the role of T(H)1, T(H)2, and T(H)17 cells in the pathogenesis of SjS.

Genetic control of disease in an experimental model for Sjögren's syndrome

Sjögren's syndrome is an autoimmune disease with a complex etiology depending on hereditary and environmental factors. The disease is characterized by lymphocytic infiltration and inflammation in the salivary and lacrimal glands, leading to oral and ocular dryness. To understand the genetic susceptibility in Sjögren's syndrome, studies of disease phenotypes have been performed in the non-obese diabetic (NOD) mouse. By the identification of genetic regions controlling development of autoimmune exocrinopathy in the NOD mouse and by reducing one of these regions considerably, Nguyen et al. in a recent issue of Arthritis Research and Therapy propose candidate genes for development of Sjögren's syndrome.