Cuong Q. Nguyen

Salivary gland tissue expression of interleukin-23 and interleukin-17 in Sjogren's syndrome: findings in humans and mice.

OBJECTIVE Recently, the Th1/Th2 paradigm has been expanded by the discovery of Th17 cells, a subset of CD4+ memory T cells characterized by their unique ability to secrete interleukin-17 (IL-17) family cytokines. Importantly, Th17 cells appear to be intimately involved in autoimmunity. We undertook the present study to investigate whether the Th17/IL-23 system is up-regulated in Sjögrens syndrome (SS). METHODS Sera, saliva, and salivary glands from C57BL/6.NOD-Aec1Aec2 mice (a model for primary SS), as well as sera, saliva, and salivary gland biopsy specimens obtained from patients with primary SS, were evaluated for IL-17 and IL-23 expression by immunohistochemistry, real-time polymerase chain reaction, and the Luminex system. RESULTS Immunohistochemical stainings of submandibular glands from C57BL/6.NOD-Aec1Aec2 mice and of salivary gland biopsy specimens from SS patients revealed strong positive staining for both IL-17 and IL-23 within lymphocytic foci and diffuse staining on epithelial tissues. Temporal expression of IL-17 and IL-23 in submandibular glands of C57BL/6.NOD-Aec1Aec2 mice correlated with expression of retinoic acid-related orphan receptor gammat, the Th17 cell master control gene. While IL-17 could not be detected in saliva from 4-20-week-old C57BL/6.NOD-Aec1Aec2 mice, this cytokine was present in the blood of mice up to age 16 weeks. This contrasted with sera and saliva from SS patients, in which IL-17 and IL-6 were present at varying levels. CONCLUSION These results suggest that the Th17/IL-23 system is up-regulated in C57BL/6.NOD-Aec1Aec2 mice and SS patients at the time of disease. A correlation between up-regulated IL-17/IL-23 expression and specific clinical manifestations of SS has yet to be identified.

Unraveling the Pathophysiology of Sjogren Syndrome-Associated Dry Eye Disease

Sjogren syndrome (SS) is one of the most common autoimmune diseases. Early clinical manifestations of SS are primarily decreased tear and saliva secretion, leading to dry eye and dry mouth syndromes, but in its later stages, it can become systemic, even resulting in B cell lymphomas. The use of new animal models, coupled with new technologies, is providing exciting insights into the pathogenesis, genetic predisposition, and, possibly, early diagnosis of SS. This article reviews newly described features of SS identified in experimental animal models and their relationship to human disease. New technologies, such as genomics and proteomics, may permit identification of potential candidate genes and biomarkers for disease diagnosis. Current studies using appropriate animal models in parallel with studies of human subjects are rapidly establishing a foundation for new intervention strategies that go beyond merely treating symptoms.

A chemical genetic roadmap to improved tomato flavor

Looking for lost flavor in tomatoes Commercially available tomatoes are renowned these days for sturdiness, but perhaps not for flavor. Heirloom varieties, on the other hand, maintain the richer flavors and sweeter tomatoes of years past. Tieman et al. combined tasting panels with chemical and genomic analyses of nearly 400 varieties of tomatoes. They identified some of the flavorful components that have been lost over time. Identification of the genes that have also gone missing provides a path forward for reinstating flavor to commercially grown tomatoes. Science, this issue p. 391 Genomic analysis shows what genes to put back to reinstate flavor in tomatoes. Modern commercial tomato varieties are substantially less flavorful than heirloom varieties. To understand and ultimately correct this deficiency, we quantified flavor-associated chemicals in 398 modern, heirloom, and wild accessions. A subset of these accessions was evaluated in consumer panels, identifying the chemicals that made the most important contributions to flavor and consumer liking. We found that modern commercial varieties contain significantly lower amounts of many of these important flavor chemicals than older varieties. Whole-genome sequencing and a genome-wide association study permitted identification of genetic loci that affect most of the target flavor chemicals, including sugars, acids, and volatiles. Together, these results provide an understanding of the flavor deficiencies in modern commercial varieties and the information necessary for the recovery of good flavor through molecular breeding.

Pathogenic effect of interleukin-17A in induction of Sjögren's syndrome-like disease using adenovirus-mediated gene transfer

IntroductionSjögrens syndrome (SS) involves a chronic, progressive inflammation primarily of the salivary and lacrimal glands leading to decreased levels of saliva and tears resulting in dry mouth and dry eye diseases. Seminal findings regarding TH17 cell populations that secrete predominantly interleukin (IL)-17A have been shown to play an important role in an increasing number of autoimmune diseases, including SS. In the present study, we investigated the function of IL-17A on the development and onset of SS.MethodsAdenovirus serotype 5 (Ad5) vectors expressing either IL-17A or LacZ were infused via retrograde cannulation into the salivary glands of C57BL/6J mice between 6 and 8 weeks of age or between 15 and 17 weeks of age. The mice were characterized for SS phenotypes.ResultsDisease profiling indicated that SS-non-susceptible C57BL/6J mice whose salivary glands received the Ad5-IL17A vector developed a SS-like disease profile, including the appearance of lymphocytic foci, increased cytokine levels, changes in antinuclear antibody profiles, and temporal loss of saliva flow.ConclusionsInduction of SS pathology by IL-17A in SS-non-susceptible mice strongly suggests that IL-17A is an important inflammatory cytokine in salivary gland dysfunction. Thus, localized anti-IL17 therapy may be effective in preventing glandular dysfunction.

Sjögren's syndrome: studying the disease in mice

Sjögrens 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.

Early pathogenic events associated with Sjögren's syndrome (SjS)-like disease of the nod mouse using microarray analysis

Recently, we reported development of the C57BL/6.NOD-Aec1Aec2 mouse carrying two genetic intervals derived from the NOD mouse. These two genetic regions confer full Sjögrens syndrome (SjS)-like disease in SjS-non-susceptible C57BL/6 mice. The current study was undertaken to apply microarray technology to define the molecular basis underlying onset of SjS-disease in C57BL/6.NOD-Aec1Aec2 mice. Using oligonucleotide microarrays, gene expression profiles of submandibular glands derived from 8- to 12-week-old C57BL/6.NOD-Aec1Aec2 mice and 8-week-old C57BL/6 mice were performed for comparison. Significant differential expressions were determined using the Mann–Whitney U test. Hybridizations using submandibular cDNA probes revealed 75 differentially expressed genes at 8 weeks and 105 differentially expressed genes at 12 weeks of age in C57BL/6.NOD-Aec1Aec2 mice compared to 8-week-old C57BL/6 mice. These genes were related generally to basic cellular activities such as transcription, translation, DNA replication, and protein folding. During the predisease phase, genes upregulated encode proteins associated with the IFN-gamma signal-transduction-pathway (Jak/Stat1), TLR-3 (Irf3 and Traf6) and apoptosis (casp11 and casp3), indicative of chronic proinflammatory stimuli, especially IL-1. Between 8 and 12 weeks of age, sets of clustered genes were upregulated that are associated with adaptive immune responses, especially B cell activation, proliferation and differentiation (Baffr, Taci, Bcma, Blys, April, CD70, CD40L, Traf1, Traf3, Pax5, c-Jun, Elk1 and Nf-kB), and neural receptors (Taj/Troy). Altered gene expressions of TLR3 and TNF-superfamily-receptors and ligands during this early phase of SjS suggest a possible viral etiology in the altered glandular homeostasis with an upregulated, possibly overstimulated, B-lymphocyte activation in the early autoimmune response present in the submandibular glands. The importance of NF-κB as a critical signal transduction pathway is also suggested but its link is not yet clear.

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

Sjögrens 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. TH17 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 (SSS) 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 SSS 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.

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 TH1, TH2, and TH17 cells in the pathogenesis of SjS.

IL-4-STAT6 Signal Transduction-Dependent Induction of the Clinical Phase of Sjögren’s Syndrome-Like Disease of the Nonobese Diabetic Mouse

NOD.B10-H2b and NOD/LtJ mice manifest, respectively, many features of primary and secondary Sjögren’s syndrome (SjS), an autoimmune disease affecting primarily the salivary and lacrimal glands leading to xerostomia (dry mouth) and xerophthalmia (dry eyes). B lymphocytes play a central role in the onset of SjS with clinical manifestations dependent on the appearance of autoantibodies reactive to multiple components of acinar cells. Previous studies with NOD.IL4−/− and NOD.B10-H2b.IL4−/− mice suggest that the Th2 cytokine, IL-4, plays a vital role in the development and onset of SjS-like disease in the NOD mouse model. To investigate the molecular mechanisms by which IL-4 controls SjS development, a Stat6 gene knockout mouse, NOD.B10-H2b.C-Stat6−/−, was constructed and its disease profile was defined and compared with that of NOD.B10-H2b.C-Stat6+/+ mice. As the NOD.B10-H2b.C-Stat6−/− mice aged from 4 to 24 wk, they exhibited leukocyte infiltration of the exocrine glands, produced anti-nuclear autoantibodies, and showed loss and gain of saliva-associated proteolytic enzymes, similar to NOD.B10-H2b.C-Stat6+/+ mice. In contrast, NOD.B10-H2b.C-Stat6−/− mice failed to develop glandular dysfunction, maintaining normal saliva flow rates. NOD.B10-H2b.C-Stat6−/− mice were found to lack IgG1 isotype-specific anti-muscarinic acetylcholine type-3 receptor autoantibodies. Furthermore, the IgG fractions from NOD.B10-H2b.C-Stat6−/− sera were unable to induce glandular dysfunction when injected into naive recipient C57BL/6 mice. NOD.B10-H2b.C-Stat6−/− mice, like NOD.B10-H2b.IL4−/− mice, are unable to synthesize IgG1 Abs, an observation that correlates with an inability to develop end-stage clinical SjS-like disease. These data imply a requirement for the IL-4/STAT6-pathway for onset of the clinical phase of SjS-like disease in the NOD mouse model.

Current Concepts: Mouse Models of Sjögren's Syndrome

Sjögrens syndrome (SjS) is a complex chronic autoimmune disease of unknown etiology which primarily targets the exocrine glands, resulting in eventual loss of secretory function. The disease can present as either primary SjS or secondary SjS, the latter of which occurs concomitantly with another autoimmune disease such as rheumatoid arthritis, systemic lupus erythematosus, scleroderma, or primary biliary cirrhosis. Current advancements in therapeutic prevention and treatment for SjS are impeded by lack of understanding in the pathophysiological and clinical progression of the disease. Development of appropriate mouse models for both primary and secondary SjS is needed in order to advance knowledge of this disease. This paper details important features, advantages, and pitfalls of current animal models of SjS, including spontaneous, transgenic, knockout, immunization, and transplantation chimera mouse models, and emphasizes the need for a better model in representing the human SjS phenotype.