Development of Sjogren's syndrome in nonobese diabetic-derived autoimmune-prone C57BL/6.NOD-Aec1Aec2 mice is dependent on complement component-3

B Cells Dynamic in Aging and the Implications of Nutritional Regulation

Aging negatively affects B cell production, resulting in a decrease in B-1 and B-2 cells and impaired antibody responses. Age-related B cell subsets contribute to inflammation. Investigating age-related alterations in the B-cell pool and developing targeted therapies are crucial for combating autoimmune diseases in the elderly. Additionally, optimal nutrition, including carbohydrates, amino acids, vitamins, and especially lipids, play a vital role in supporting immune function and mitigating the age-related decline in B cell activity. Research on the influence of lipids on B cells shows promise for improving autoimmune diseases. Understanding the aging B-cell pool and considering nutritional interventions can inform strategies for promoting healthy aging and reducing the age-related disease burden.

Advances and prospects of platelet-rich plasma therapy in veterinary ophthalmology

In the recent decades, there has been a significant uptick on the use of platelet-rich plasma (PRP) as a better alternative for ophthalmologic therapies in pathologies, primarily of the ocular surface. PRP is a class of liquid platelet concentrate containing a supra-physiological concentration of platelets in a relatively small amount of plasma. Its potential to heal various tissues has piqued interest in its therapeutic application as a biomaterial in regenerative medicine. It is currently a popular therapeutic agent in plastic surgery, cardiothoracic surgery, reconstructive surgery, and even oral and maxillofacial surgery. Based on the data from in vitro and in vivo studies, it can be concluded that PRP possesses adequate therapeutic potential in ocular pathologies, especially those involving cornea. In addition, the high concentrations of growth factors (TGF-β, VEGF, EGF) present in the PRP accelerate the healing of the corneal epithelium. PRP has great therapeutic prospects in veterinary ophthalmology as a regenerative therapeutic modality. However, several variables are yet to be defined and standardized that can directly affect the efficacy of PRP application in different ophthalmic conditions. There is a shortage of research on the use of PRP in ocular surface defects compared to the number of studies and reports on the use of autologous and allogeneic serum eye drops. Therefore, a data-driven approach is required to generate consensus/guidelines for the preparation, characterization, and therapeutic use of PRP in veterinary ophthalmology. This review aims to inform readers of the latest research on PRP, including its preparation methods, physiological and biochemical properties, clinical applications in veterinary ophthalmology, and their safety and efficacy.

Marginal Zone B (MZB) Cells: Comparison of the Initial Identification of Immune Activity Leading to Dacryoadenitis and Sialadenitis in Experimental Sjögren's Syndrome

Although multiple mouse strains have been advanced as models for Sjögren's syndrome (SS), which is a human systemic autoimmune disease characterized primarily as the loss of lacrimal and salivary gland functions, the C57BL/6.NOD-Aec1Aec2 recombinant inbred (RI) mouse derived from the NOD/ShiLtJ line is considered one of the more appropriate models exhibiting virtually all the characteristics of the human disease. This mouse model, as well as other mouse models of SS, have shown that B lymphocytes are essential for the onset and development of observed clinical manifestations. Recently, studies carried out in the C57BL/6.IL14α transgenic mouse have provided clear evidence that the marginal zone B (MZB) cell population is directly involved in the early pathological events initiating the development of the clinical SS disease, as well as late-stage lymphomagenesis resulting in B-cell lymphomas. Since MZB cells are difficult to study in vivo and in vitro, we carried out a series of ex vivo investigations that utilize temporal global RNA transcriptomic analyses to profile differentially expressed genes exhibiting temporal upregulation during the initial onset and subsequent development of pathophysiological events within the lacrimal and salivary gland tissues per se or associated with the leukocyte cell migrations into these glands. The initial transcriptomic analyses revealed that while the upregulated gene expression profiles obtained from lacrimal and salivary glands overlap, multiple genetic differences exist between the defined activated pathways. In the current study, we present a concept suggesting that the initial pathological events differ between the two glands, yet the subsequent upregulated TLR4/TLR3 signal transduction pathway that activates the type-1 interferon signature appears to be identical in the two glands and indicates an autoimmune response against dsRNA, possibly a virus. Here, we attempt to put these findings into perspective and determine how they can impact the design of future therapeutic protocols.

Current experimental methods to investigate the impact of specialized pro-resolving lipid mediators on Sjögren's syndrome

Sjögren's syndrome is a chronic inflammatory autoimmune disease characterized by diminished secretory function of the exocrine glands. Although extensive investigation has been done to understand Sjögren's syndrome, the causes of the disease are as yet unknown and treatments remain largely ineffective, with established therapeutic interventions being limited to use of saliva substitutes with modest effectiveness. A primary feature of Sjögren's syndrome is uncontrolled inflammation of exocrine tissues and previous studies have demonstrated that lipid-based specialized pro-resolving mediators reduce inflammation and restores tissue integrity in salivary glands. However, these studies are limited to a single specialized pro-resolving lipid mediator's family member resolvin D1 or RvD1 and its aspirin-triggered epimer, AT-RvD1. Consequently, additional studies are needed to explore the potential benefits of other members of the specialized pro-resolving lipid mediator's family and related molecules (e.g., additional resolvin subtypes as well as lipoxins, maresins and protectins). In support of this goal, the current review aims to briefly describe the range of current experimental methods to investigate the impact of specialized pro-resolving lipid mediators on Sjögren's syndrome, including both strengths and weaknesses of each approach where this information is known. With this article, the possibilities presented by specialized pro-resolving lipid mediators will be introduced to a wider audience in immunology and practical advice is given to researchers who may wish to take up this work.

Optimization of a Plasma Rich in Growth Factors Membrane for the Treatment of Inflammatory Ocular Diseases

The main purpose of the present study is to develop an immunosafe fibrin membrane obtained by plasma rich in growth factors technology (is-mPRGF) with improved mechanical properties that could be applied in patients with inflammatory ocular diseases. Blood was drawn from three healthy donors and centrifuged, and the collected PRGF was activated and distributed into two groups: (i) mPRGF: a PRGF membrane maintained at 37 °C for 30 min; (ii) IS5+30: mPRGF incubated at 37 °C for 5 min and then incubated at 56 °C for 30 min. The content of both membranes was analyzed for several growth factors such as IgE and the complement activation, as well as biological activity on different ocular surface cells. Furthermore, the physical and mechanical characterizations were also evaluated. IS5+30 completely reduced the complement activity and decreased the IgE while preserving the concentration of the main growth factors. IS5+30 induced similar biological activity regarding mPRGF on the different ocular surface cells analyzed. Furthermore, no significant differences in release kinetics or fibrin degradation were observed between both membranes. Summarizing, IS5+30 totally reduces complement activity while preserving the concentration of most growth factors and their biological activity. Furthermore, the physical and mechanical properties of the fibrin membrane are preserved after heat inactivation.

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.

Effect of Myd88 deficiency on gene expression profiling in salivary glands of female non-obese diabetic (NOD) mice

OBJECTIVES

Sjögren's syndrome (SS) is a chronic autoimmune disease characterized by inflammatory lesions in the salivary and lacrimal glands, which are caused by distinct lymphocytic infiltrates. Female non-obese diabetic (NOD) mice spontaneously develop inflammatory lesions of the salivary glands with SS-like pathological features. Previous studies have shown that MyD88, a crucial adaptor protein that activates innate immune signaling, affects lymphocytic infiltration, but its detailed role remains unclear. In this study, we investigated the role of MyD88 through gene expression profiling in the early phase of pathogenesis in the salivary glands of female NOD mice.

METHODS

Submandibular glands collected from 10-week-old female wild-type and Myd88-deficient NOD mice were used for RNA preparation, followed by microarray analysis. The microarray dataset was analyzed to identify Myd88-dependent differentially expressed genes (DEGs). Data generated were used for GO enrichment, KEGG pathway, STRING database, and INTERFEROME database analyses.

RESULTS

Myd88 deficiency was found to affect 230 DEGs, including SS-associated genes, such as Cxcl9 and Bpifa2. Most of the DEGs were identified as being involved in immunological processes. KEGG pathway analysis indicated that the DEGs were putatively involved in autoimmune diseases, such as systemic lupus erythematosus and rheumatoid arthritis. Furthermore, the DEGs included 149 interferon (IFN)-regulated genes.

CONCLUSIONS

MyD88 is involved in the expression of specific genes associated with IFN-associated immunopathological processes in the salivary glands of NOD mice. Our findings are important for understanding the role of MyD88-dependent innate immune signaling in SS manifestation.

The Involvement of Innate and Adaptive Immunity in the Initiation and Perpetuation of Sjögren's Syndrome

Sjogren’s syndrome (SS) is a chronic autoimmune disease characterized by the infiltration of exocrine glands including salivary and lachrymal glands responsible for the classical dry eyes and mouth symptoms (sicca syndrome). The spectrum of disease manifestations stretches beyond the classical sicca syndrome with systemic manifestations including arthritis, interstitial lung involvement, and neurological involvement. The pathophysiology underlying SS is not well deciphered, but several converging lines of evidence have supported the conjuncture of different factors interplaying together to foster the initiation and perpetuation of the disease. The innate and adaptive immune system play a cardinal role in this process. In this review, we discuss the inherent parts played by both the innate and adaptive immune system in the pathogenesis of SS.

Development and optimization of a personalized fibrin membrane derived from the plasma rich in growth factors technology

PURPOSE

To develop and characterize a new type of plasma rich in growth factors (PRGF) membrane for patients in which immune system is involved in the disease etiology.

METHODS

Blood from three healthy donors was collected to obtain the different fibrin membranes by PRGF technology. PRGF obtained volumes were activated and divided into two groups: PRGF membrane (mPRGF) obtained after incubation at 37 °C for 30 min (control); and is-mPRGF: mPRGF obtained after incubation for 30 min at 56 °C. The concentration of several growth factors, proteins, immunoglobulin E and the complement activity was determined in the different mPRGF. The proliferative potential of heat-inactivated mPRGF were assayed on keratocytes (HK) and conjunctival fibroblasts (HConF). In addition, morphological and physical features of the inactivated mPRGF were evaluated in contrast to the control mPRGF.

RESULTS

Heat-inactivation of the mPRGF preserves the content of most of the growth factors involved in the ocular wound healing while reducing drastically the content of IgE and the complement activity. The heat-inactivated mPRGF conserve the morphological and physical characteristics of the fibrin meshwork in comparison with the control mPRGF. Furthermore, no significant differences were found in the biological activity of the control mPRGF regarding the heat-inactivated mPRGF (is-mPRGF) in any of both ocular cell types evaluated.

CONCLUSIONS

The heat-inactivation of the PRGF membranes (is-mPRGF) reduces drastically the content of IgE and complement activity while preserving the content of most of the proteins and morphogens involved in ocular wound healing. Furthermore, the morphological and physical features of the immunosafe mPRGF were also preserved after heat-inactivation.

Innate Immunity and Biological Therapies for the Treatment of Sjögren's Syndrome

Sjögren's syndrome (SS) is a systemic autoimmune disorder affecting approximately 3% of the population in the United States. This disease has a female predilection and affects exocrine glands, including lacrimal and salivary glands. Dry eyes and dry mouths are the most common symptoms due to the loss of salivary and lacrimal gland function. Symptoms become more severe in secondary SS, where SS is present along with other autoimmune diseases like systemic lupus erythematosus, systemic sclerosis, or rheumatoid arthritis. It is known that aberrant activation of immune cells plays an important role in disease progression, however, the mechanism for these pathological changes in the immune system remains largely unknown. This review highlights the role of different immune cells in disease development, therapeutic treatments, and future strategies that are available to target various immune cells to cure the disease.

Testosterone Influence on Gene Expression in Lacrimal Glands of Mouse Models of Sjögren Syndrome

Purpose

Sjögren syndrome is an autoimmune disorder that occurs almost exclusively in women and is associated with extensive inflammation in lacrimal tissue, an immune-mediated destruction and/or dysfunction of glandular epithelial cells, and a significant decrease in aqueous tear secretion. We discovered that androgens suppress the inflammation in, and enhance the function of, lacrimal glands in female mouse models (e.g., MRL/MpJ-Tnfrsf6^lpr [MRL/lpr]) of Sjögren syndrome. In contrast, others have reported that androgens induce an anomalous immunopathology in lacrimal glands of nonobese diabetic/LtJ (NOD) mice. We tested our hypothesis that these hormone actions reflect unique, strain- and tissue-specific effects, which involve significant changes in the expression of immune-related glandular genes.

Methods

Lacrimal glands were obtained from age-matched, adult, female MRL/lpr and NOD mice after treatment with vehicle or testosterone for up to 3 weeks. Tissues were processed for analysis of differentially expressed mRNAs using CodeLink Bioarrays and Affymetrix GeneChips. Data were analyzed with bioinformatics and statistical software.

Results

Testosterone significantly influenced the expression of numerous immune-related genes, ontologies, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in lacrimal glands of MRL/lpr and NOD mice. The nature of this hormone-induced immune response was dependent upon the autoimmune strain, and was not duplicated within lacrimal tissues of nonautoimmune BALB/c mice. The majority of immune-response genes regulated by testosterone were of the inflammatory type.

Conclusions

Our findings support our hypothesis and indicate a major role for the lacrimal gland microenvironment in mediating androgen effects on immune gene expression.

Submandibular gland-specific inflammaging-induced hyposalivation in the male senescence-accelerated mouse prone -1 line (SAM-P1)

Aging has pronounced effects on mammalian tissues and cells, but the impacts of aging on salivary gland function are relatively unknown. This study aims to evaluate the effects of aging on submandibular gland (SMG) and parotid gland (PG) functions in the male senescence-accelerated mouse. In vivo analysis at the systemic level revealed that salivary secretion induced by pilocarpine, a muscarinic agonist, from the SMG was significantly decreased in aged mice, whereas salivary secretion from the PG was not affected. To evaluate organ-level function, the SMG was perfused with the muscarinic agonists carbachol and calcium ionophore A23187 ex vivo to induce salivary secretion, and decreased saliva production was also observed in the aged SMG. Histological analysis revealed the presence of CD4-positive lymphocytes infiltrating the aged SMG. Furthermore, real-time PCR revealed that the aged SMG exhibited accelerated cell aging, increased levels of the inflammatory cytokine interleukin-6, and decreased mRNA levels of the water channel protein aquaporin-5 (AQP5). In summary, these results demonstrate that SMG function in aged mice was diminished, and that cell senescence, chronic inflammation, and the decreased gene expression of AQP5 are the likely causes of hyposalivation in the SMG of aged mice.

B cells in the pathogenesis of primary Sjögren syndrome

Primary Sjögren syndrome (pSS) is a prototypical autoimmune disease. The involvement of B cells in the pathogenesis of pSS has long been suspected on the basis of clinical observations that include the presence of serum autoantibodies, hypergammaglobulinaemia, increased levels of free light chains and increased risk of B cell lymphoma. Moreover, the composition of the B cell subset is altered in pSS. In this Review, we discuss the mechanisms that support the increased activation of B cells in pSS, including genetic and epigenetic factors and environmental triggers that promote B cell activation via the innate immune system. B cell activating factor (BAFF, also known as TNF ligand superfamily member 13B) is at the crossroads of this process. An important role also exists for the target tissue (exocrine glands, namely the salivary and lachrymal glands), which promotes local B cell activation. This continuous stimulation of B cells is the main driver of lymphomatous escape. Identification of the multiple steps that support B cell activation has led to the development of promising targeted therapies that will hopefully lead to the development of an efficient therapeutic strategy for pSS.

AT-RvD1 combined with DEX is highly effective in treating TNF-α-mediated disruption of the salivary gland epithelium

Sjögren's syndrome (SS) is an autoimmune disorder characterized by chronic inflammation and destruction of salivary and lacrimal glands leading to dry mouth and dry eyes, respectively. Currently, the etiology of SS is unknown and the current therapies have no permanent benefit; therefore, new approaches are necessary to effectively treat this condition. Resolvins are highly potent endogenous lipid mediators that are synthesized during the resolution of inflammation to restore tissue homeostasis. Previous studies indicate that the resolvin family member, RvD1, binds to the ALX/FPR2 receptor to block inflammatory signals caused by tumor necrosis factor-alpha (TNF-α) in the salivary epithelium. More recently, the corticosteroid, dexamethasone (DEX), was shown to be effective in reducing salivary gland inflammation. However, DEX, as with other corticosteroids, elicits adverse secondary effects that could be ameliorated when used in smaller doses. Therefore, we investigated whether the more stable aspirin-triggered (AT) epimer, AT-RvD1, combined with reduced doses of DEX is effective in treating TNF-α-mediated disruption of polarized rat parotid gland (Par-C10) epithelial cell clusters. Our results indicate that AT-RvD1 and DEX individually reduced TNF-α-mediated alteration in the salivary epithelium (i.e, maintained cell cluster formation, increased lumen size, reduced apoptosis, and preserved cell survival signaling responses) as compared to untreated cells. Furthermore, AT-RvD1 combined with a reduced dose of DEX produced stronger responses (i.e., robust salivary cell cluster formation, larger lumen sizes, further reduced apoptosis, and sustained survival signaling responses) as compared to those observed with individual treatments. These studies demonstrate that AT-RvD1 combined with DEX is highly effective in treating TNF-α-mediated disruption of salivary gland epithelium.

Myd88 is required for disease development in a primary Sjögren's syndrome mouse model

Sjögren's syndrome (SS) is an autoimmune disease that often results in diminished exocrine gland function. SS patients also experience systemic disease manifestations, including hypergammaglobulinemia and pulmonary and renal pathoses. MyD88 is a ubiquitously expressed adaptor molecule used by all immune cells that is required for IL-1 receptor (IL-1R), IL-18R, and most TLR signaling. The precise role of MyD88 in SS has not been evaluated, although this adaptor is critical for development of lupus, a related autoimmune disease. This study tested the hypothesis that Myd88-mediated signaling is required for local and systemic SS manifestations. To this end, we generated NOD.B10Sn-H2^b /J (NOD.B10) mice that are deficient in Myd88 (NOD.B10 ^Myd88-/- ). We found that NOD.B10 animals that lack Myd88 show reduced exocrine and extraglandular inflammation. Moreover, these animals are protected from loss of salivary flow. Splenocytes from NOD.B10 ^Myd88-/- mice did not up-regulate activation markers or secrete IL-6 in response to a Myd88-dependent agonist, although BCR signaling remained intact. Finally, IgM, IgG, and anti-nuclear autoantibodies were reduced in NOD.B10 ^Myd88-/- mice compared with the parental strain. These data demonstrate that Myd88 is a crucial mediator of local and systemic SS disease manifestations.

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.

Multiple Roles for B-Lymphocytes in Sjogren's Syndrome

Sjogren’s syndrome (SS) is a complex heterogeneous autoimmune disease resulting in loss of salivary gland and lacrimal gland function that may include multiple systemic manifestations including lymphoma. Multiple cell types participate in disease pathogenesis. This review discusses evidence for abnormal B cell subpopulations in patients with SS, critical roles of B cells in SS and the status of B cell–directed therapies in the management of patients with SS.

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.

Targeting of Ly9 (CD229) Disrupts Marginal Zone and B1 B Cell Homeostasis and Antibody Responses

Marginal zone (MZ) and B1 B cells have the capacity to respond to foreign Ags more rapidly than conventional B cells, providing early immune responses to blood-borne pathogens. Ly9 (CD229, SLAMF3), a member of the signaling lymphocytic activation molecule family receptors, has been implicated in the development and function of innate T lymphocytes. In this article, we provide evidence that in Ly9-deficient mice splenic transitional 1, MZ, and B1a B cells are markedly expanded, whereas development of B lymphocytes in bone marrow is unaltered. Consistent with an increased number of these B cell subsets, we detected elevated levels of IgG3 natural Abs and a striking increase of T-independent type II Abs after immunization with 2,4,6-trinitrophenyl-Ficoll in the serum of Ly9-deficient mice. The notion that Ly9 could be a negative regulator of innate-like B cell responses was supported by the observation that administering an mAb directed against Ly9 to wild-type mice selectively eliminated splenic MZ B cells and significantly reduced the numbers of B1 and transitional 1 B cells. In addition, Ly9 mAb dramatically diminished in vivo humoral responses and caused a selective downregulation of the CD19/CD21/CD81 complex on B cells and concomitantly an impaired B cell survival and activation in an Fc-independent manner. We conclude that altered signaling caused by the absence of Ly9 or induced by anti-Ly9 may negatively regulate development and function of innate-like B cells by modulating B cell activation thresholds. The results suggest that Ly9 could serve as a novel target for the treatment of B cell-related diseases.

Tear proteomic analysis of Sjögren syndrome patients with dry eye syndrome by two-dimensional-nano-liquid chromatography coupled with tandem mass spectrometry

We examined the tear film proteome of patients with Sjögren's syndrome (SS) and dry eye syndrome (group A), patients with dry eye symptoms (group B) and normal volunteers (group C). Tear samples were pooled from 8 subjects from each group and were subjected to two-dimensional-nano-liquid chromatography coupled with tandem mass spectrometry (2D-nano-LC-MS/MS). The tear breakup time for group A was significantly reduced compared with group B and C (P < 0.001). Group A (Schirmer I test, 2.13 ± 2.38 mm/5 min) had markedly lower tear volume than group B (5.94 ± 4.75 mm/5 min) and C (14.44 ± 6.57 mm/5 min) (P < 0.001). Group A had significantly higher normalized tear protein content (1.8291 ± 0.2241 μg/mm) than group B (1.0839 ± 0.1120 μg/mm) (P = 0.001) and C (0.2028 ± 0.0177 μg/mm) (P = 0.001). The 2D-nano-LC-MS/MS analysis identified a total of 435 proteins, including 182 (54.8%), 247 (74.4%) and 278 (83.7%) in group A, B, and C, respectively, with 56 (16.7%) proteins including defensin α1, clusterin and lactotransferrin unique to group A. In conclusion, dry eye syndrome in SS patients is associated with an altered proteomic profile with dysregulated expression of proteins involved in a variety of important cellular process including inflammation, immunity, and oxidative stress.

Innate immune signaling induces interleukin-7 production from salivary gland cells and accelerates the development of primary Sjögren's syndrome in a mouse model

Elevated IL-7 in the target tissues is closely associated with multiple autoimmune disorders, including Sjögren’s syndrome (SS). We recently found that IL-7 plays an essential role in the development and onset of primary SS (pSS) in C57BL/6.NOD-Aec1Aec2 mice, a well-defined mouse model of primary SS. However, environmental signals that cause excessive IL-7 production are not well-characterized. Innate immune signaling plays a critical role in shaping the adaptive immune responses including autoimmune responses. We and others have previously shown that innate immune signaling can induce IL-7 expression in lungs and intestines of C57BL/6 mice. In this study, we characterized the effects of poly I:C, a double-stranded RNA analog and toll-like receptor 3 agonist, on the induction of IL-7 expression in salivary glands and on pSS development. We showed that poly I:C administration to C57BL/6 mice rapidly induced IL-7 expression in the salivary glands in a type 1 IFN- and IFN-γ-dependent manner. Moreover, poly I:C-induced IL-7 contributed to the optimal up-regulation of CXCL9 in the salivary glands, which may subsequently promote recruitment of more IFN-γ-producing T cells. Repeated administration of poly I:C to C57BL/6.NOD-Aec1Aec2 mice accelerated the development of SS-like exocrinopathy, and this effect was abolished by the blockade of IL-7 receptor signaling with a neutralizing antibody. Finally, poly I:C or a combination of IFN-α and IFN-γ induced IL-7 gene expression and protein production in a human salivary gland epithelial cell line. Hence, we demonstrate that IL-7 expression in the salivary gland cells can be induced by poly I:C and delineate a crucial mechanism by which innate immune signals facilitate the development of pSS, which is through induction of IL-7 in the target tissues.

Interleukin-7 enhances the Th1 response to promote the development of Sjögren's syndrome-like autoimmune exocrinopathy in mice

OBJECTIVE

Although elevated interleukin-7 (IL-7) levels have been reported in patients with primary Sjögren's syndrome (SS), the role of IL-7 in this disease remains unclear. We undertook this study to characterize the previously unexplored role of IL-7 in the development and onset of primary SS using the C57BL/6.NOD-Aec1Aec2 (B6.NOD-Aec) mouse model, which recapitulates human primary SS.

METHODS

For gain-of-function studies, recombinant IL-7 or control phosphate buffered saline was injected intraperitoneally (IP) into 12-week-old B6.NOD-Aec mice for 8 weeks. For loss-of-function studies, anti-IL-7 receptor α-chain (anti-IL-7Rα) antibody or its isotype control IgG was administered IP into 16-week-old B6.NOD-Aec mice. Salivary flow measurement, histologic and flow cytometric analysis of salivary glands, and serum antinuclear antibody assay were performed to assess various disease parameters.

RESULTS

Administration of exogenous IL-7 accelerated the development of primary SS, whereas blockade of IL-7Rα signaling almost completely abolished the development of primary SS, based on salivary gland inflammation and apoptosis, autoantibody production, and secretory dysfunction. IL-7 positively regulated interferon-γ (IFNγ)-producing Th1 and CD8+ T cells in the salivary glands without affecting IL-17. Moreover, IL-7 enhanced the expression of CXCR3 ligands in a T cell- and IFNγ-dependent manner. Accordingly, IFNγ induced a human salivary gland epithelial cell line to produce CXCR3 ligands. IL-7 also increased the level of tumor necrosis factor α, another Th1-associated cytokine that can facilitate tissue destruction and inflammation.

CONCLUSION

IL-7 plays a pivotal pathogenic role in SS, which is underpinned by an enhanced Th1 response and IFNγ/CXCR3 ligand-mediated lymphocyte infiltration of target organs. These results suggest that targeting the IL-7 pathway may be a potential future strategy for preventing and treating SS.

Conjunctival inflammation in thrombospondin-1 deficient mouse model of Sjögren's syndrome

Lacrimal gland inflammation during autoimmune Sjögren's syndrome (SS) leads to ocular surface inflammation - Keratoconjunctivitis sicca (KCS). This condition afflicts both the cornea and conjunctiva that form the ocular surface. Thrombospondin-1 (TSP-1) deficiency in mice results in lacrimal gland and corneal inflammation that resembles the human disease. In this study we report conjunctival pathology in this mouse model of SS. We found that TSP-1 null mice develop inflammation in the conjunctiva and associated loss of goblet cell function similar to that seen in patients with SS. Increased expression of Th1 (IFN-γ, TNF-α) and Th17 (IL-6, IL-17A) inflammatory cytokines and related transcription factors (Tbet and RORγt) were detected in TSP-1 null conjunctiva as well as their draining lymph nodes (LNs). The conjunctival inflammation was also accompanied by an increase in local lymphatic vessels. Interestingly, migration of antigen-bearing dendritic cells (DCs) from the ocular surface to the LNs was dependent on the TSP-1 available in the tissue. These results not only reveal potential immunopathogenic mechanisms underlying KCS in SS but also highlight the therapeutic potential of TSP-1.

Transient depletion of CD4+ CD25+ regulatory T cells results in multiple autoimmune diseases in wild-type and B-cell-deficient NOD mice

Approximately 80% of female wild-type non-obese diabetic (WT NOD) mice spontaneously develop diabetes, whereas B-cell-deficient (B(-/-)) NOD mice are resistant to diabetes. B(-/-) mice are also resistant to other spontaneous and experimentally induced autoimmune diseases, including arthritis, systemic lupus erythematosus, Sjögren syndrome and thyroiditis. Under normal conditions, activation of self-reactive T cells in the periphery is limited by CD4(+) CD25(+) natural regulatory T (Treg) cells. B(-/-) NOD.H-2h4 mice, normally resistant to spontaneous autoimmune thyroiditis (SAT), develop SAT when Treg cells are depleted, suggesting that Treg cells are preferentially activated when autoantigen is initially presented by non-B-cell antigen-presenting cells. To test the hypothesis that increased Treg cell activity in B(-/-) mice contributes to their resistance to other autoimmune diseases, WT and B(-/-) NOD mice were given anti-CD25 to transiently deplete CD4(+) CD25(+) Treg cells. The WT and B(-/-) NOD mice given anti-CD25 developed diabetes much earlier than WT mice given rat IgG, whereas rat IgG-treated B(-/-) mice did not develop diabetes. Treg-cell-depleted mice had increased lymphocyte infiltration of the pancreas, salivary glands and thyroid compared with controls given rat IgG. These results are consistent with the hypothesis that resistance of B-cell-deficient NOD mice to several autoimmune diseases is due to the activity of Treg cells.

Intrinsic molecular factors cause aberrant expansion of the splenic marginal zone B cell population in nonobese diabetic mice

Marginal zone (MZ) B cells are an innate-like population that oscillates between MZ and follicular areas of the splenic white pulp. Differentiation of B cells into the MZ subset is governed by BCR signal strength and specificity, NF-κB activation through the B cell-activating factor belonging to the TNF family (BAFF) receptor, Notch2 signaling, and migration signals mediated by chemokine, integrin, and sphingosine-1-phosphate receptors. An imbalance in splenic B cell development resulting in expansion of the MZ subset has been associated with autoimmune pathogenesis in various murine models. One example is the NOD inbred mouse strain, in which MZ B cell expansion has been linked to development of type 1 diabetes and Sjögren's syndrome. However, the cause of MZ B cell expansion in this strain remains poorly understood. We have determined that increased MZ B cell development in NOD mice is independent of T cell autoimmunity, BCR specificity, BCR signal strength, and increased exposure to BAFF. Rather, mixed bone marrow chimeras showed that the factor(s) responsible for expansion of the NOD MZ subset is B cell intrinsic. Analysis of microarray expression data indicated that NOD MZ and precursor transitional 2-MZ subsets were particularly dysregulated for genes controlling cellular trafficking, including Apoe, Ccbp2, Cxcr7, Lgals1, Pla2g7, Rgs13, S1pr3, Spn, Bid, Cd55, Prf1, and Tlr3. Furthermore, these B cell subsets exhibited an increased steady state dwell time within splenic MZ areas. Our data therefore reveal that precursors of mature B cells in NOD mice exhibit an altered migration set point, allowing increased occupation of the MZ, a niche favoring MZ B cell differentiation.

Transcriptome analysis of the interferon-signature defining the autoimmune process of Sjögren's syndrome

Sjögren's syndrome (SS) of humans and SS-like (SjS-like) diseases in mouse models are characterized by chronic immune attacks against the salivary and lacrimal glands leading to exocrine dysfunction. One characteristic of SS and SjS-like diseases repeatedly observed is a strong upregulated expression of both the type I (α/β) and type II (γ) interferons (IFNs). In addition, recent global transcriptome studies have identified a variety of IFN-stimulated gene (ISG) transcripts differentially expressed in tissues of SS patients and mouse models exhibiting SjS-like disease. Analyses of these transcriptome databases indicate that the sets of differentially expressed genes are highly restricted, suggesting that there is a unique specificity in ISGs activated (or suppressed) during development and onset of disease. As a result, these observations have led to both SS and SjS-like diseases being designated as 'interferon-signature' diseases. While SS and SjS-like diseases may be designated as such, very little effort has been made to determine what an interferon-signature might signify relative to autoinflammation and whether it might point directly to an underlying etiopathological mechanism. Here, we review these limited data and provide a model of how the products of these genes interact molecularly and biologically to define critical details of SS pathology.

B-cell tolerance defects in the B6.Aec1/2 mouse model of Sjögren's syndrome

PURPOSE

Primary Sjögren's syndrome (SjS) is an autoimmune disorder characterized by lymphocytic infiltration of the salivary and lacrimal glands, B-cell clonal expansions and an increased risk of lymphoma. In order to understand the role of B cells in this disorder, the antibody repertoire and B-cell maturation were studied in a mouse model of SjS called B6.Aec1/2.

METHODS

B6.Aec1/2 serum was analyzed for antibodies by ELISA and immunoprecipitation, B-cell development by flow cytometry, and antibody gene rearrangements by CDR3 spectratyping and quantitative PCR. In order to test the functional consequences of the observed defects, B6.Aec1/2 mice were crossed with anti-dsDNA antibody heavy chain knock-in mice (B6.56R).

RESULTS

B6.Aec1/2 mice exhibit B-cell clonal expansions, have altered serum immunoglobulin levels and spontaneously produce multireactive autoantibodies. B6.Aec1/2 mice also have decreased numbers of bone marrow pre-B cells and decreased frequencies of kappa light chain gene deletion. These findings suggest that B6.Aec1/2 mice have a defective early B-cell tolerance checkpoint. B6.56R.Aec1/2 mice unexpectedly had lower anti-dsDNA antibody levels than B6.56R mice and less salivary gland infiltration than B6.Aec1/2 mice.

CONCLUSIONS

These data suggest that the early tolerance checkpoint defect in B6.Aec1/2 mice is not sufficient to promulgate disease in mice with pre-formed autoantibodies, such as B6.56R. Rather, B6.Aec1/2 mice may require a diverse B-cell repertoire for efficient T-B-cell collaboration and disease propagation. These findings imply that therapies aimed at reducing B-cell diversity or T-B interactions may be helpful in treating SjS.

Salivary PYY: a putative bypass to satiety

Peptide YY_3-36 is a satiation hormone released postprandially into the bloodstream from L-endocrine cells in the gut epithelia. In the current report, we demonstrate PYY_3-36 is also present in murine as well as in human saliva. In mice, salivary PYY_3-36 derives from plasma and is also synthesized in the taste cells in taste buds of the tongue. Moreover, the cognate receptor Y2R is abundantly expressed in the basal layer of the progenitor cells of the tongue epithelia and von Ebner's gland. The acute augmentation of salivary PYY_3-36 induced stronger satiation as demonstrated in feeding behavioral studies. The effect is mediated through the activation of the specific Y2 receptor expressed in the lingual epithelial cells. In a long-term study involving diet-induced obese (DIO) mice, a sustained increase in PYY_3-36 was achieved using viral vector-mediated gene delivery targeting salivary glands. The chronic increase in salivary PYY_3-36 resulted in a significant long-term reduction in food intake (FI) and body weight (BW). Thus this study provides evidence for new functions of the previously characterized gut peptide PYY_3-36 suggesting a potential simple and efficient alternative therapeutic approach for the treatment of obesity.

Microarray analysis of sexually dimorphic gene expression in human minor salivary glands

OBJECTIVE

We hypothesized that differential mRNA transcription between the sexes may be linked to the 9:1 female-to-male gender-related relative risk for the development of Sjögren's syndrome (SS), an autoimmune disease that leads to inflammation and dysfunction in the lachrymal and salivary glands.

SUBJECTS AND METHODS

RNA from minor salivary glands was collected from nine healthy volunteers (four men and five women) and analyzed using the Agilent 4 × 44K human microarray platform. Differential expression was confirmed by qRT-PCR.

RESULTS

Comparison of the transcriptome of minor salivary glands from normal male and female volunteers with that of salivary glands and secretory epithelia identified a number of gender, species, and tissue-specific gene expression patterns. These differences include, but are not limited to, a diverse set of genes involved in immune modulation, chemotactic control, inhibition of complement, metabolism, and neurogenesis.

CONCLUSION

Analysis of these changes provides insight into the protective and predisposing molecular factors that may be involved in the development of Sjögren's syndrome. Some of the gene changes observed in this study correlate with previously observed sexual dimorphisms in salivary gland function and also illustrate several new targets for further investigation.

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.

Dysfunction of lacrimal and salivary glands in Sjögren's syndrome: nonimmunologic injury in preinflammatory phase and mouse model

Sjögren's syndrome (SjS) is a chronic autoimmune disorder characterized by dry eyes and dry mouth due to dacryoadenitis and sialoadenitis with SS-A/Ro and/or SS-B/La autoantibodies in genetically predisposed individuals. Destruction of lacrimal and salivary glands by autoimmune reactions may lead to clinical manifestation. However, the mechanisms behind the decreased volume of secretions in tears and saliva are complex and are not fully understood. Exocrine gland dysfunction may precede autoimmunity (acquired immunity) or represent a process independent from inflammation in the pathogenesis of SjS. The preceded functional and morphologic changes of those tissues by nonimmunologic injury before the development of inflammation at the sites of target organs have been implicated. This paper focuses on the several factors and components relating to glandular dysfunction and morphologic changes by nonimmunologic injury during the preinflammatory phase in mouse model, including the factors which link between innate immunity and adaptive immunity.

IL17: potential therapeutic target in Sjögren's syndrome using adenovirus-mediated gene transfer

Sjögren's syndrome (SS) involves a chronic, progressive inflammation primarily of the salivary and lacrimal glands leading to decreased levels of saliva and tears that eventually result in dry mouth and dry eye diseases. T(H)17 cell populations secreting IL17A have been shown to have an important function in an increasing number of autoimmune diseases, including SS. In this study, we investigated the function of IL17A on SS development and onset. Adenovirus-5 vectors expressing either IL17R:fragment of crystallization (Fc) fusion protein or LacZ were injected through retrograde cannulation into the salivary glands of SS-susceptible (SS(S)) C57BL/6.NOD-Aec1Aec2 mice between 6 and 8 weeks of age (a pre-disease stage) or 15 and 17 weeks of age (a diseased stage). The mice were subsequently characterized for their SS phenotypes. Mice cannulated with the Ad5-IL17R:Fc viral vector at either 7 or 16 weeks of age exhibited a rapid temporal, yet persistent, decrease in the levels of serum IL17 as well as the overall numbers of CD4+IL17+T cells present in their spleens. Disease profiling indicated that these mice showed decreased lymphocytic infiltrations of their salivary glands, normalization of their antinuclear antibodies repertoire, and increased saliva secretion. In contrast, mice cannulated with the control Ad5-LacZ viral vector did not exhibit similar changes and progressed to the overt disease stage. The capacity of the Ad5-IL17R:Fc-blocking factor to reduce SS pathology in SS(S) mice strongly suggests that IL17 is an important inflammatory cytokine in salivary gland dysfunction. Thus, therapeutic approach targeting IL17 may be effective in preventing glandular dysfunction.

An NZW-derived interval on chromosome 7 moderates sialadenitis, but not insulitis in congenic nonobese diabetic mice

Autoimmune lymphocytic infiltration of the salivary glands, termed sialadenitis, is a pathologic feature of Sjögren's syndrome (SjS) that is also prominent in nonobese diabetic (NOD) mice. Genetic factors regulate sialadenitis, and a previous (NOD x NZW)F2 study detected linkage to murine chromosome (Chr) 7. The locus, subsequently annotated as Ssial3, maps to the distal end of Chr7 and overlaps a region associated with type 1 diabetes susceptibility in NOD mice. To examine whether Ssial3 could contribute to both diseases, or was specific for SjS, we generated a congenic mouse strain that harbored an NZW-derived Chr7 interval on the NOD genetic background. This congenic strain exhibited reduced sialadenitis compared with NOD mice and confirmed Ssial3. This reduction, however, did not ameliorate saliva abnormalities associated with SjS-like disease in NOD mice, nor were congenic mice protected against insulitis (lymphocytic infiltration of the pancreatic islets) or diabetes onset. Thus, the Ssial3 locus appears to have a tissue-specific effect for which the NZW allele is unable to prevent other autoimmune traits in the NOD mouse. Anomalous increases for antinuclear Ab production and frequency of marginal-zone B cells were also identified in congenic mice, indicating that the NZW-derived Chr7 interval has a complex effect on the NOD immune system.

Local expression of tumor necrosis factor-receptor 1:immunoglobulin G can induce salivary gland dysfunction in a murine model of Sjögren's syndrome

Introduction

Tumor necrosis factor is a pleiotropic cytokine with potent immune regulatory functions. Although tumor necrosis factor inhibitors have demonstrated great utility in treating other autoimmune diseases, such as rheumatoid arthritis, there are conflicting results in Sjögren's syndrome. The aim of this study was to assess the effect of a locally expressed tumor necrosis factor inhibitor on the salivary gland function and histopathology in an animal model of Sjögren's syndrome.

Methods

Using in vivo adeno associated viral gene transfer, we have stably expressed soluble tumor necrosis factor-receptor 1-Fc fusion protein locally in the salivary glands in the Non Obese Diabetic model of Sjögren's syndrome. Pilocarpine stimulated saliva flow was measured to address the salivary gland function and salivary glands were analyzed for focus score and cytokine profiles. Additionally, cytokines and autoantibody levels were measured in plasma.

Results

Local expression of tumor necrosis factor-receptor 1:immunoglobulin G fusion protein resulted in decreased saliva flow over time. While no change in lymphocytic infiltrates or autoantibody levels was detected, statistically significant increased levels of tumor growth factor-β1 and decreased levels of interleukin-5, interleukin-12p70 and interleukin -17 were detected in the salivary glands. In contrast, plasma levels showed significantly decreased levels of tumor growth factor-β1 and increased levels of interleukin-4, interferon-γ, interleukin-10 and interleukin-12p70.

Conclusions

Our findings suggest that expression of tumor necrosis factor inhibitors in the salivary gland can have a negative effect on salivary gland function and that other cytokines should be explored as points for therapeutic intervention in Sjögren's syndrome.

Pathogenesis of Sjögren's syndrome

PURPOSE OF REVIEW

To summarize recent developments in our understanding of the pathogenesis of Sjögren's syndrome with a focus on the relationship between inflammation and exocrine dysfunction.

RECENT FINDINGS

Animal models demonstrated the complex interactions between immunologic and nonimmunologic mechanisms in Sjögren's syndrome. Activation of the innate immune system can lead to exocrine dysfunction before or without significant inflammation, whereas in other models, salivary gland function is preserved despite intense inflammatory infiltrates. Primary or inflammation-related abnormalities in water channels contribute to the exocrinopathy. Activation of the innate immunity in patients is demonstrated by the upregulation of type-1 interferon-regulated genes (interferon signature) in peripheral blood and salivary glands and abnormal expression of B cell-activating factor and its receptors. Nonimmune mechanisms that may contribute to exocrine dysfunction include local and systemic androgen deficiency and autonomic nervous system dysfunction. Autoantibodies against the muscarinic acetylcholine receptors would provide a link between autoimmunity and exocrine dysfunction, but the data on the presence, frequency and physiologic affect of these antibodies remain controversial.

SUMMARY

Recent discoveries from studies in patients with Sjögren's syndrome and animal models suggest a complex interplay between genetic factors, environmental and stochastic events that involve innate and adaptive immunity, hormonal mechanisms and the autonomic nervous system. Some of these findings suggest that exocrine gland dysfunction may precede autoimmunity or represent a process independent from inflammation in the pathogenesis of Sjögren's syndrome.

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.

Cellular and humoral immune responses in the early stages of diabetic nephropathy in NOD mice

This study was designed to examine immunopathology of diabetic nephropathy in non-obese diabetic (NOD) mice and to investigate the involvement of cellular and humoral immunity at various time points after diabetes onset. We found that the glomeruli of diabetic NOD mice were infiltrated with T and B cells, as well as CD11c+ dendritic cells, which had close contact with CD4+ and CD8+ T cells in the infiltrates. We also found that IgG deposits in the glomeruli of diabetic NOD mice were accompanied by the presence of complement C3. Moreover, the serum from diabetic mice contained autoantibodies directed towards components of the glomeruli and these antibodies were not present in non-diabetic NOD mice. The immune changes in the kidney occurred together with increasing kidney weight and urinary albumin excretion along with duration of diabetes. We provide evidence that infiltrating lymphocytes and anti-kidney autoantibodies may be involved in diabetic nephropathy in autoimmune diabetes in the NOD mouse. Understanding the role that the immune system plays in the pathogenesis of diabetic nephropathy could lead to identification of new strategies and/or additional therapeutic targets for prevention and treatment of diabetic nephropathy.

Dry eye and designer ophthalmics

Expressed sequence tag (EST), proteomic, and antibody capture assays are revealing a level of tear film protein complexity far greater than previously appreciated. A systems biology approach will be needed to fully appreciate function as tear protein doses fluctuate in time through different conditions. Although consensus is growing on what fully constitutes the human tear proteome, questions remain about the source and significance of the approximately 256 tear proteins designated as "intracellular." Many of these may derive from normal cellular turnover and could therefore be informative. A further >183 are designated as "extracellular." Surprisingly, only 4 to 5% of these appear to be dysregulated in the three forms of dry eye preliminarily examined to date. Some differ and a couple overlap, suggesting that disease-specific signatures could be identified. Future dry eye treatment might include recombinant tear protein rescue as a personalized ophthalmic approach to ocular surface disease.

Biomarker profiles in serum and saliva of experimental Sjögren's syndrome: associations with specific autoimmune manifestations

INTRODUCTION

Sjögren's syndrome (SS) is a systemic autoimmune disease that mainly targets the exocrine glands. The aim of this study was to investigate the involvement of 87 proteins measured in serum and 75 proteins analyzed in saliva in spontaneous experimental SS. In addition, we intended to compute a model of the immunological situation representing the overt disease stage of SS.

METHODS

Nondiabetic, nonobese diabetic (NOD) mice aged 21 weeks were evaluated for salivary gland function, salivary gland inflammation and extraglandular disease manifestations. The analytes, comprising chemokines, cytokines, growth factors, autoantibodies and other biomarkers, were quantified using multi-analyte profile technology and fluorescence-activated cell sorting. Age-matched and sex-matched Balb/c mice served as a reference.

RESULTS

We found NOD mice to exhibit impaired salivary flow, glandular inflammation and increased secretory SSB (anti-La) levels. Thirty-eight biomarkers in serum and 34 in saliva obtained from NOD mice were significantly different from those in Balb/c mice. Eighteen biomarkers in serum and three chemokines measured in saliva could predict strain membership with 80% to 100% accuracy. Factor analyses identified principal components mostly correlating with one clinical aspect of SS and having distinct associations with components extracted from other families of proteins.

CONCLUSION

Autoimmune manifestations of SS are greatly independent and associated with various immunological processes. However, CD40, CD40 ligand, IL-18, granulocyte chemotactic protein-2 and anti-muscarinic M3 receptor IgG3 may connect the different aspects of SS. Processes related to the adaptive immune system appear to promote SS with a strong involvement of T-helper-2 related proteins in hyposalivation. This approach further established saliva as an attractive biofluid for biomarker analyses in SS and provides a basis for the comparison and selection of potential drug targets and diagnostic markers.