The Role of ACAID and CD4+CD25+FOXP3+ Regulatory T Cells on CTL Function Against MHC Alloantigens

Purpose: Anterior chamber associated immune deviation (ACAID) is an antigen-specific form of peripheral immune tolerance that is induced to exogenous antigens placed in the ocular anterior chamber, which leads to a suppression in delayed-type hypersensitivity (DTH). Considerable work has been done on ACAID induction to major histocompatibility (MHC) alloantigens. However, its role on cytotoxic T lymphocyte (CTL) activity is currently unknown. Methods: C57BL/6 (H-2b) mice received an intracameral (IC) inoculation with BALB/c (H-2d) splenocytes. Splenic CD4+ and CD8+ T cell populations were characterized by flow cytometry and proliferation assays during induction and expression phases of ACAID. Percentages of CD4+CD25+FoxP3+ T regulatory cells (Treg) were also followed. Lastly, CTL function was measured at various time points during ACAID expression, and Treg were added to identify potential alterations in CTL function. Results: CD4+ and CD8+ T cell percentages and proliferation increased in the spleen during ACAID induction but then sharply decreased in response to an allospecific immunization. Expression of ACAID also exhibited a significant drop in CTL function. However, while Treg expansion was observed, these cells did not directly mediate the CTL inhibition. Conclusions: ACAID mediates an inhibition of CTL function against MHC alloantigens. Furthermore, we found that ACAID induction leads to the expansion and proliferation of CD4+ and CD8+ T cells while ACAID expression is associated with a diminishment in T cell percentages due to proliferation impairment. Lastly, Treg also expand during ACAID induction. However, our data suggest that Treg do not directly inhibit CTL activity

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

Introduction Sjögren's 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. Methods Adenovirus 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. Results Disease 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. Conclusions Induction 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.National Institute of Dental and Craniofacial Research (U.S.) (PHS Grants K99DE018958)National Institute of Allergy and Infectious Diseases (U.S.) (R21AI081952)Sjogren's Syndrome FoundationUniversity of Florida. Center for Orphaned Autoimmune DisordersNational Institute of Dental and Craniofacial Research (U.S.) (Intramural research grant)National Institutes of Health (U.S.

Systems analysis of primary Sjögren's syndrome pathogenesis in salivary glands identifies shared pathways in human and a mouse model

Introduction: Primary Sjogren's syndrome (pSS) is a chronic autoimmune disease with complex etiopathogenesis. Despite extensive studies to understand the disease process utilizing human and mouse models, the intersection between these species remains elusive. To address this gap, we utilized a novel systems biology approach to identify disease-related gene modules and signaling pathways that overlap between humans and mice. Methods: Parotid gland tissues were harvested from 24 pSS and 16 non-pSS sicca patients and 25 controls. For mouse studies, salivary glands were harvested from C57BL/6.NOD-Aec1Aec2 mice at various times during development of pSS-like disease. RNA was analyzed with Affymetrix HG U133+2.0 arrays for human samples and with MOE430+2.0 arrays for mouse samples. The images were processed with Affymetrix software. Weighted-gene co-expression network analysis was used to identify disease-related and functional pathways. Results: Nineteen co-expression modules were identified in human parotid tissue, of which four were significantly upregulated and three were downregulated in pSS patients compared with non-pSS sicca patients and controls. Notably, one of the human disease-related modules was highly preserved in the mouse model, and was enriched with genes involved in immune and inflammatory responses. Further comparison between these two species led to the identification of genes associated with leukocyte recruitment and germinal center formation. Conclusion: Our systems biology analysis of genome-wide expression data from salivary gland tissue of pSS patients and from a pSS mouse model identified common dysregulated biological pathways and molecular targets underlying critical molecular alterations in pSS pathogenesis

The Interferon-signature of Sjögren’s Syndrome: How Unique Biomarkers Can Identify Underlying Inflammatory and Immunopathological Mechanisms of Specific Diseases

Innate immune responses direct the nature and specificity of downstream adaptive responses in autoimmune diseases. One of the strongest markers of innate immunity is the up-regulated expression of interferon (IFN) and IFN-responsive/stimulated genes (IRGs/ISGs). While multiple IRGs are induced during the innate phase of host responses, transcriptome data suggest unique IRG-signatures for different diseases. Sjögren’s syndrome (SjS) is characterized by chronic immune attacks against exocrine glands leading to exocrine dysfunction, plus strong up-regulated expressions of IFN IRG transcripts. Genome-wide transcriptome analyses indicate that differentially-expressed IRGs are restricted during disease development and therefore define underlying etiopathological mechanisms. Here we review the innate immune-associated IFN-signature of SjS and show how differential gene expressions of IRG/ISG sets interact molecularly and biologically to identify critical details of SjS etiopathogenesis

A Temporal Comparative RNA Transcriptome Profile of the Annexin Gene Family in the Salivary versus Lacrimal Glands of the Sjögren’s Syndrome-Susceptible C57BL/6.NOD-<i>Aec1Aec2</i> Mouse

A generally accepted hypothesis for the initial activation of an immune or autoimmune response argues that alarmins are released from injured, dying and/or activated immune cells, and these products complex with receptors that activate signal transduction pathways and recruit immune cells to the site of injury where the recruited cells are stimulated to initiate immune and/or cellular repair responses. While there are multiple diverse families of alarmins such as interleukins (IL), heat-shock proteins (HSP), Toll-like receptors (TLR), plus individual molecular entities such as Galectin-3, Calreticulin, Thymosin, alpha-Defensin-1, RAGE, and Interferon-1, one phylogenetically conserved family are the Annexin proteins known to promote an extensive range of biomolecular and cellular products that can directly and indirectly regulate inflammation and immune activities. For the present report, we examined the temporal expression profiles of the 12 mammalian annexin genes (Anxa1-11 and Anxa13), applying our temporal genome-wide transcriptome analyses of ex vivo salivary and lacrimal glands from our C57BL/6.NOD-Aec1Aec2 mouse model of Sjögren’s Syndrome (SS), a human autoimmune disease characterized primarily by severe dry mouth and dry eye symptoms. Results indicate that annexin genes Anax1-7 and -11 exhibited upregulated expressions and the initial timing for these upregulations occurred as early as 8 weeks of age and prior to any covert signs of a SS-like disease. While the profiles of the two glands were similar, they were not identical, suggesting the possibility that the SS-like disease may not be uniform in the two glands. Nevertheless, this early pre-clinical and concomitant upregulated expression of this specific set of alarmins within the immune-targeted organs represents a potential target for identifying the pre-clinical stage in human SS as well, a fact that would clearly impact future interventions and therapeutic strategies

Sjögren’s syndrome: studying the disease in mice

Sjögren’s syndrome (SS), a systemic autoimmune disease, is characterized by infl ammation of exocrine tissues accompanied by a signifi cant 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 eff ect 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 Covert Appearance of Marginal Zone B Cells in Salivary Glands of Sjögren′s Syndrome-Susceptible Mice: Initiators of Subsequent Overt Clinical Disease

The C57BL/6.NOD-Aec1Aec2 mouse model has been extensively studied to define the underlying cellular and molecular bioprocesses critical in the onset of primary Sjögren’s Syndrome (pSS), a human systemic autoimmune disease characterized clinically as the loss of lacrimal and salivary gland functions leading to dry eye and dry mouth pathologies. This mouse model, together with several gene knockout mouse models of SS, has indicated that B lymphocytes, especially marginal zone B (MZB) cells, are necessary for development and onset of clinical manifestations despite the fact that destruction of the lacrimal and salivary gland cells involves a classical T cell-mediated autoimmune response. Because migrations and functions of MZB cells are difficult to study in vivo, we have carried out ex vivo investigations that use temporal global RNA transcriptomic analyses to profile autoimmunity as it develops within the salivary glands of C57BL/6.NOD-Aec1Aec2 mice. Temporal profiles indicate the appearance of Notch2-positive cells within the salivary glands of these SS-susceptible mice concomitant with the early-phase appearance of lymphocytic foci (LF). Data presented here identify cellular bioprocesses occurring during early immune cell migrations into the salivary glands and suggest MZB cells are recruited to the exocrine glands by the upregulated Cxcl13 chemokine where they recognize complement (C’)-decorated antigens via their sphingosine-1-phosphate (S1P) and B cell (BC) receptors. Based on known MZB cell behavior and mobility, we propose that MZB cells activated in the salivary glands migrate to splenic follicular zones to present antigens to follicular macrophages and dendritic cells that, in turn, promote a subsequent systemic cell-mediated and autoantibody-mediated autoimmune T cell response that targets exocrine gland cells and functions. Overall, this study uses the power of transcriptomic analyses to provide greater insight into several molecular events defining cellular bioprocesses underlying SS that can be modelled and more thoroughly studied at the cellular level