Extraction of characteristic serum microRNAs and prediction of target genes in IgG4-related dacryoadenitis and sialadenitis.

OBJECTIVES: To identify the specific microRNAs (miRNAs) in IgG4-related dacryoadenitis and sialadenitis (IgG4-DS) and predict the targeted genes. METHODS: miRNAs in the serum of nine patients with IgG4-DS, three patients with primary Sjögren's syndrome, and three healthy controls were analysed using the human miRNA chip, and miRNAs that exhibited significant fluctuation in expression in IgG4-DS patients were extracted. The respective target genes were predicted using an existing database, and expression of the target genes was evaluated in actual submandibular gland tissues affected by IgG4-DS. RESULTS: Serum miR-125a-3p and miR-125b-1-3p levels were elevated in IgG4-DS. Six candidate target genes (glypican 4, forkhead box C1, protein tyrosine phosphatase non-receptor type 3, hydroxycarboxylic acid receptor 1, major facilitator superfamily domain containing 11, and tumour-associated calcium signal transducer 2) were downregulated in the affected submandibular gland tissue. CONCLUSION: Overexpression of miR-125a-3p and miR-125b-1-3p is a hallmark of IgG4-DS. These miRNAs appear to be involved in the pathogenesis of IgG4-DS.

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.

The underlying mechanisms and strategies of DNA damage and repair in radiation sialadenitis.

Radiation therapy is a critical strategy for the treatment of malignant tumors. X-ray external radiation has been successfully used to treat head and neck cancer. On the other hand, 131 I internal radiation has been effective in managing differentiated thyroid cancer. However, these therapies cause radiation damage to salivary glands. Radiation sialadenitis is the most common complication associated with radiotherapy applied to the head and neck and it severely affects patients' quality of life. Since DNA is the main intracellular target of radiation, and the integrity of the DNA structure is critical to genomic stability and the cellular survival of salivary glands, regulating radiation-induced DNA damage offers great promise in preventing and managing radiation sialadenitis. In this review, we summarize recent progress in DNA damage and repair in irradiated salivary glands.

McH-lpr/lpr-RA1 mice: A novel spontaneous mouse model of autoimmune sialadenitis.

Many studies of the autoimmune disease Sjögren's syndrome have been performed using spontaneous mouse models. In the present study, we describe the characteristics of McH/lpr-RA1 mice and propose their use as a novel murine model of autoimmune sialadenitis. The McH/lpr-RA1 mouse is a recombinant congenic strain derived from generation F54 or more of MRL-Faslpr x (MRL- Faslpr x C3H- Faslpr) F1. We show for the first time that this mouse spontaneously develops autoimmune sialadenitis and vasculitis in submandibular gland tissues. Sialadenitis was accompanied by extensive inflammatory cell infiltration and tissue destruction. Immunohistochemical studies revealed that the salivary gland lesions strongly expressed four sialadenitis-related molecules: SSA and SSB (autoantigens of Sjögren's syndrome), gp91phox (an accelerator of reactive oxygen species production) and single strand DNA (a marker of apoptotic cells). In contrast, expression of aquaporin-5 (AQP5), which stimulates salivary secretion was weak or negligible. Statistical correlation analyses indicated that the apoptosis of salivary gland cells provoked by oxidative stress contributed to the severe sialadenitis and reduced expression of AQP5. Our study has demonstrated that McH/lpr-RA1 mice spontaneously develop the pathognomonic features of autoimmune sialadenitis and thus could be used as a new animal model of Sjögren's syndrome.

Acute Sialadenitis in Children With Acute Leukemia During Chemotherapy: A Case Series Study.

Complications and toxicities of chemotherapy are the significant causes of morbidity and mortality during the treatment of childhood leukemias. Respiratory viral infections are the most common cause of febrile neutropenia episodes and rarely spread to the salivary glands. We submitted 4 patients with acute leukemia who got diagnosed with acute sialadenitis during their chemotherapy period.

Association of a dysbiotic oral microbiota with the development of focal lymphocytic sialadenitis in IκB-ζ-deficient mice.

Mice lacking IκB-ζ, a protein encoded by the Nfkbiz gene, spontaneously develop a Sjögren's syndrome-like disease involving the lachrymal glands, but no salivary gland symptoms have been reported. We found that Nfkbiz-/- female mice presented a significantly reduced salivary flow rate, focal lymphocytic sialadenitis (FLS), and a dysbiotic oral microbiota at week 24. To dissect the contributions of genetic and environmental factors to the salivary gland phenotype, Nfkbiz+/+ and Nfkbiz-/- mice were cohoused after weaning and evaluated at week 20. Cohousing alleviated the salivary gland phenotype of Nfkbiz-/- mice but did not induce any disease phenotype in Nfkbiz+/+ mice. Additionally, the oral microbiota in the cohoused mice was synchronized toward that in Nfkbiz+/+ mice. In conclusion, IκB-ζ-deficient mice developed hyposalivation and FLS, in which a dysbiotic oral microbiota played an important role. This finding suggests that the dysbiotic oral microbiota could be a therapeutic target.

Pathophysiology of IgG4-related disease: A T follicular helper cells disease?

IgG4-related disease is a chronic inflammatory disease characterized by clinical, biological and pathological unifying findings. Because these criteria are not always all together available in patients and because biological and pathological markers are not totally specific, the diagnosis should be retained after exclusion of mimickers. Since the individualization of IgG4-RD, several studies have allowed to better characterize immunological abnormalities associated with this particular condition. B and T cell oligoclonal activation is associated with T helper 2 cytokine production leading to IgG4 production and profibrotic cytokine release. A central role for T follicular helper 2 cells is suggested from recent findings. We summarize here recent advances in understanding of immune abnormalities in IgG4-related disease.

Targeted TNF-α Overexpression Drives Salivary Gland Inflammation.

Chronic inflammation of the salivary glands from pathologic conditions such as Sjögren's syndrome can result in glandular destruction and hyposalivation. To understand which molecular factors may play a role in clinical cases of salivary gland hypofunction, we developed an aquaporin 5 (AQP5) Cre mouse line to produce genetic recombination predominantly within the acinar cells of the glands. We then bred these mice with the TNF-αglo transgenic line to develop a mouse model with salivary gland-specific overexpression of TNF-α; which replicates conditions seen in sialadenitis, an inflammation of the salivary glands resulting from infection or autoimmune disorders such as Sjögren's syndrome. The resulting AQP5-Cre/TNF-αglo mice display severe inflammation in the salivary glands with acinar cell atrophy, fibrosis, and dilation of the ducts. AQP5 expression was reduced in the salivary glands, while tight junction integrity appeared to be disrupted. The immune dysregulation in the salivary gland of these mice led to hyposalivation and masticatory dysfunction.

Up-regulation of activation-induced cytidine deaminase and its strong expression in extra-germinal centres in IgG4-related disease.

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is a systemic disorder involving benign mass formation due to fibrosis and intense lymphoplasmacytosis; the chronic inflammation associated with the disease might also contribute to oncogenesis. Activation-induced cytidine deaminase (AID), normally expressed in germinal centre activated B-cells, is an enzyme that edits DNA/RNA and induces somatic hypermutation and Ig class switching. AID expression is strictly controlled under physiological conditions; however, chronic inflammation and some infectious agents induce its up-regulation. AID is overexpressed in various cancers and may be important in chronic inflammation-associated oncogenesis. We examined AID expression in IgG4-related sialadenitis (n = 14), sialolithiasis (non-specific inflammation, n = 13), and normal submandibular glands (n = 13) using immunohistochemistry and quantitative real-time polymerase chain reaction (qPCR). Immunohistochemistry revealed significantly more AID-expressing cells in IgG4-related sialadenitis than in sialolithiasis or normal submandibular gland samples (P = 0.02 and P < 0.01, respectively); qPCR yielded similar results. Thus, AID was significantly more up-regulated and had higher expression in extra-germinal centres in IgG4-RD than in non-specific inflammation or normal conditions. This report suggests that IgG4-RD has several specific causes of AID up-regulation in addition to inflammation. Furthermore, chronic inflammation-associated AID-mediated oncogenesis is possible in IgG4-RD.

The synergistic effect of NOD2 and TLR4 on the activation of autophagy in human submandibular gland inflammation.

BACKGROUND: Sialadenitis is a nonneoplastic disease that causes salivary dysfunction. Autophagy may be involved in helping protect salivary function when the salivary gland is impaired; this process is primarily activated by sensors of innate immunity, such as Toll-like receptors and nucleotide-binding oligomerization domain (NOD)-like receptors. The role of these pattern recognition receptors (PRRs) in the regulation of salivary gland tissue defense and homeostasis has been underappreciated. This study hypothesized that NOD2 and TLR4 have a synergistic effect on the activation of autophagy in human submandibular gland (HSG) inflammation. METHODS: Submandibular gland inflammation was modeled by treating HSG cell lines in vitro with muramyl dipeptide (MDP) and lipopolysaccharide (LPS) for 24 hours. The mRNA and protein expression of NOD2, TLR4 and autophagy-related proteins (ATG5, LC3, Beclin1) were evaluated by real-time PCR and Western blot. Immunohistochemistry and double immunofluorescence were used to analyze the presence, distribution and colocalization of the aforementioned indicators in HSG tissues. RESULT: The mRNA and protein expression of autophagy-related proteins were significantly increased in HSG cells costimulated with LPS and MDP for 24 hours. NOD2, TLR4 and the autophagy-related proteins were also highly expressed in residual acini and dilated ducts of chronic submandibular sialadenitis tissues. In addition, PRRs and autophagy markers were obviously colocalized in chronic submandibular sialadenitis tissues and HSG cells. CONCLUSION: TLR4 and NOD2 have unique expression sites in salivary glands, and they may synergistically activate autophagy in salivary glands under conditions of inflammation.

MyD88 signaling causes autoimmune sialadenitis through formation of high endothelial venules and upregulation of LTß receptor-mediated signaling.

Autoimmune sialadenitis (AS), chronic inflammation of the salivary glands (SGs) with focal lymphocyte infiltration, appears in autoimmune diseases such as SjÓ§gren's syndrome. The pathological role of MyD88-dependent innate immune signaling in autoimmune diseases including AS has been studied using mouse models, such as NOD mice. Although AS development in NOD mice was reported to be suppressed by Myd88 deficiency, its specific role remains unclear. Here, we determined the potent suppressive effects of Myd88 deficiency on AS development in lupus-prone B6/lpr mice, which have lymphoproliferation abnormalities, and also in NOD mice, which have no lymphoproliferation abnormalities. This indicates that MyD88 signaling triggers AS through both lymphoproliferation-dependent and -independent mechanisms. To address the MyD88-dependent lymphoproliferation-independent AS manifestation, SGs from C57BL/6 mice were analyzed. Remarkable upregulation of Glycam1 and high endothelial venule (HEV)-associated changes were unexpectedly found in Myd88+/+ mice, compared with Myd88-/- mice. MyD88-dependent HEV-associated changes were also observed in NOD mice. Additionally, Lta, Ltb, and Ltbr in SGs of NOD mice were lowered by Myd88 deficiency. Interestingly, LTßR-induced HEV-associated gene expression in cultured cells was impaired by Myd88 deficiency. Our findings highlight novel roles for MyD88 in AS development, which imply the existence of MyD88-dependent HEV formation in ectopic lymphoid neogenesis.

Low miR200b-5p levels in minor salivary glands: a novel molecular marker predicting lymphoma development in patients with Sjögren's syndrome.

OBJECTIVES: Development of non-Hodgkin's lymphoma (NHL) is the major adverse outcome of Sjögren's syndrome (SS) affecting both morbidity and mortality. Preliminary evidence suggested that, although not deregulated compared with sicca controls, miR200b-5p levels are decreased in the minor salivary glands (MSGs) of SS patients with NHL. The aim of the current study was to evaluate the MSG expression of miR200b-5p in SS-associated NHLs and its potential predictive value for the identification of patients with SS susceptible to develop NHL. METHODS: miR200b-5p expression was investigated in MSG tissues of patients with SS who were at: (A) low risk and did not develop NHL during follow-up (n=27; median follow-up time on biopsy performance, range: 8.9 years, 1.33-14 years), (B) high-risk and diagnosed with NHL during follow-up (prelymphoma; n=17; median follow-up to until lymphoma diagnosis, range: 3.67 years, 0.42-8.5 years) and (C) had NHL (n=35), as well as non-SS sialadenitis controls (sarcoidosis and hepatitis C virus (HCV) infection, four each). The differential miR200b-5p expression, correlations with disease features and its discriminative/predictive value, was evaluated by appropriate statistical approaches. RESULTS: The MSG levels of miR200b-5p were significantly downregulated in patients with SS who will develop or have NHL and strongly discriminated (p<0.0001) them from those without lymphoma or non-SS sialadenitis. Furthermore, they were reduced long before clinical onset of lymphoma, did not significantly change on transition to lymphoma and, importantly, were proved strong independent predictors of patients who will develop NHL (p<0.0001). CONCLUSIONS: These findings support that miR200b-5p levels in MSGs represent a novel predictive and possibly pathogenetic mechanism-related factor for the development of SS-associated NHL, since its expression is impaired years before lymphoma clinical onset.

P2Y2 R deletion ameliorates sialadenitis in IL-14α-transgenic mice.

OBJECTIVE: Interleukin-14α-transgenic (IL-14αTG) mice develop an autoimmune exocrinopathy with characteristics similar to Sjögren's syndrome, including sialadenitis and hyposalivation. The P2Y2 receptor (P2Y2 R) for extracellular ATP and UTP is upregulated during salivary gland inflammation (i.e., sialadenitis) where it regulates numerous inflammatory responses. This study investigated the role of P2Y2 Rs in autoimmune sialadenitis in the IL-14αTG mouse model of Sjögren's syndrome. MATERIALS AND METHODS: IL-14αTG mice were bred with P2Y2 R-/- mice to generate IL-14αTG × P2Y2 R-/- mice. P2Y2 R expression, lymphocytic focus scores, B- and T-cell accumulation, and lymphotoxin-α expression were evaluated in the submandibular glands (SMG) along with carbachol-stimulated saliva secretion in IL-14αTG, IL-14αTG × P2Y2 R-/- , and C57BL/6 control mice at 9 and 12 months of age. RESULTS: Genetic ablation of P2Y2 Rs in IL-14αTG mice significantly reduced B and T lymphocyte infiltration of SMGs. However, reduced sialadenitis did not restore saliva secretion in IL-14αTG × P2Y2 R-/- mice. Decreased sialadenitis in IL-14αTG × P2Y2 R-/- mice correlated with decreased lymphotoxin-α levels, a critical proinflammatory cytokine associated with autoimmune pathology in IL-14αTG mice. CONCLUSIONS: The results of this study suggest that P2Y2 Rs contribute to the development of salivary gland inflammation in IL-14αTG mice and may also contribute to autoimmune sialadenitis in humans.

Lesional CD4+ IFN-γ+ cytotoxic T lymphocytes in IgG4-related dacryoadenitis and sialoadenitis.

OBJECTIVES: IgG4-related disease (IgG4-RD) is a chronic, systemic, inflammatory condition of unknown aetiology. We have recently described clonally expanded circulating CD4+ cytotoxic T lymphocytes (CTLs) in IgG4-RD that infiltrate affected tissues where they secrete interleukin (IL)-1ß and transforming growth factor -ß1 (TGF-ß1). In this study, we sought to examine the role of CD4+ CTLs in the pathogenesis of IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS) and to determine whether these cells secrete interferon-gamma (IFN-γ) at lesional sites. METHODS: Salivary glands of 25 patients with IgG4-DS, 22 patients with Sjögren's syndrome (SS), 12 patients with chronic sialoadenitis (CS) and 12 healthy controls were analysed in this study. Gene expression analysis was performed on submandibular glands (SMGs) from five patients with IgG4-DS, three with CS and three healthy controls. Infiltrating CD4+ CTLs were examined by quantitative multicolour imaging in tissue samples from 20 patients with IgG4-DS, 22 patients with SS, 9 patients with CS and 9 healthy controls. RESULTS: In IgG4-DS tissues, nine genes associated with CD4+ CTLs were overexpressed. The expression of granzyme A (GZMA) mRNA was significantly higher in samples from patients with IgG4-RD compared with corresponding tissues from SS and healthy controls. Quantitative imaging showed that infiltrating CD4+ GZMA+ CTLs were more abundant in patients with IgG4-DS than in the other groups. The ratio of CD4+GZMA+ CTLs in SMGs from patients with IgG4-DS correlated with serum IgG4 concentrations and the number of affected organs. A large fraction of CD4+GZMA+ CTLs in SMGs from patients with IgG4-DS secreted IFN-γ. CONCLUSIONS: The pathogenesis of IgG4-DS is associated with tissue infiltration by CD4+GZMA+ CTLs that secrete IFN-γ.

A Mouse Model for Dietary Xenosialitis: ANTIBODIES TO XENOGLYCAN CAN REDUCE FERTILITY.

Humans can incorporate the xenoglycan N-glycolylneuraminic acid (Neu5Gc) from the diet into reproductive tissues and secretions. Most humans also have circulating antibodies specific for this dietary xenoglycan. The potential for inflammation induced by incorporated Neu5Gc and circulating anti-Neu5Gc antibodies, termed xenosialitis, has been discussed as a factor influencing several human diseases. Potential effects of xenosialitis on human fertility remain unknown. Here, we investigate possible adverse effects of the presence of Neu5Gc on sperm or endometrium combined with anti-Neu5Gc antibodies in semen or uterine secretions in a mouse model. We use Cmah(-/-) mice, humanized for Neu5Gc deficiency. We find that the viability, migration, and capacitation of sperm with incorporated Neu5Gc are negatively affected when these are exposed to anti-Neu5Gc antibodies. In addition, we find that after copulation, activated uterine neutrophils and macrophages show increased phagocytosis of sperm in the presence of anti-Neu5Gc antibodies via the complement receptor 3 (C3R) and Fcγ I/II/III (Fc receptor). Furthermore, Neu5Gc in endometrial cells combined with the presence of anti-Neu5Gc antibodies alters the receptivity and decidualization of endometrial explants. These studies provide mechanistic insights on how Neu5Gc on sperm and/or endometrium combined with anti-Neu5Gc antibodies in semen and uterine fluid might contribute to unexplained human infertility.

Epigenetic Signatures of Salivary Gland Inflammation in Sjögren's Syndrome.

OBJECTIVE: Sjögren's syndrome (SS) is a complex multisystem autoimmune disease that results in progressive destruction of the exocrine glands. The purpose of this study was to characterize epigenetic changes in affected gland tissue and describe the relationship of these changes to known inflammatory processes. METHODS: A genome-wide DNA methylation study was performed on human labial salivary gland (LSG) biopsy samples obtained from 28 female members of the Sjögren's International Collaborative Clinical Alliance (SICCA) Registry. Gland tissue was methylotyped using the Illumina HumanMethylation450 BeadChip platform, followed by rigorous probe-filtering and data-normalization procedures. RESULTS: A genome-wide case-control study of 26 of the 28 subjects revealed 7,820 differentially methylated positions (DMPs) associated with disease status, including 5,699 hypomethylated and 2,121 hypermethylated DMPs. Further analysis identified 57 genes that were enriched for DMPs in their respective promoters; many are involved in immune response, including 2 previously established SS genetic risk loci. Bioinformatics analysis highlighted an extended region of hypomethylation surrounding PSMB8 and TAP1, consistent with an increased frequency of antigen-presenting cells in LSG tissue from the SS cases. Transcription factor motif enrichment analysis revealed the specific nature of the genome-wide methylation differences, demonstrating colocalization of SS-associated DMPs with stress- and immune response-related motifs. CONCLUSION: Our findings underscore the utility of CpG methylotyping as an independent probe of active disease processes in SS, offering unique insights into the composition of disease-relevant tissue. Methylation profiling implicated several genes and pathways previously thought to be involved in disease-related processes, as well as a number of new candidates.

Mobilization of lymphatic endothelial precursor cells and lymphatic neovascularization in primary Sjögren's syndrome.

Although lymphatic neovascularization may be a key feature of chronic inflammation, it is almost unexplored in primary Sjögren's syndrome (pSS). A recent study revealed a pro-lymphangiogenic function of interleukin (IL)-17, a leading player in pSS pathogenesis. The aims of the study were to investigate lymphangiogenic mediators and lymphatic vasculature in pSS, as well as their possible association with IL-17. Circulating lymphatic endothelial precursor cells (LEPCs) and Th17 cells were enumerated in pSS patients and healthy donors. VEGF-C and IL-17 levels were assessed in paired serum samples. Lymphatic vasculature, VEGF-C/VEGF receptor (VEGFR)-3 and IL-17 were evaluated in pSS minor salivary glands (MSGs) and compared with normal and non-specific chronic sialadenitis (NSCS) MSGs. Circulating LEPCs were expanded in pSS and correlated with circulating Th17 cells, IL-17 and VEGF-C. In pSS MSGs, a newly formed lymphatic capillary network was found within periductal inflammatory infiltrates and the number of interlobular lymphatic vessels was significantly increased compared with normal and NSCS MSGs. Strong VEGF-C expression was detected in pSS ductal epithelial cells and periductal inflammatory cells. Numerous VEGFR-3(+) infiltrating mononuclear cells were exclusively observed in pSS MSGs. VEGFR-3 expression was strongly increased in lymphatic capillaries of pSS MSGs. IL-17(+) inflammatory cells were preferentially observed around lymphatic vessels in pSS MSGs. This study supports the notion that lymphvasculogenesis and lymphangiogenesis are active in pSS, thereby unmasking a novel aspect of disease pathogenesis. In addition, our results suggest another possible pathogenic role of IL-17 in pSS, further supporting its therapeutic targeting in this disease.

Inducing Specific Immune Tolerance to Prevent Type 1 Diabetes in NOD Mice.

OBJECTIVES: Proinsulin is the first autoantigen in type 1 diabetes (T1D). We reasoned that coupling hematopoietic stem cells (HSCs) transplantation with ex vivo transduction of syngeneic HSCs with lentiviral vectors to express proinsulin II could prevent T1D in nonobese diabetic (NOD) mice. METHODS: Hematopoietic stem cells were isolated from 6- to 8-week-old NOD female mice and transduced in vitro with lentiviral vectors encoding proinsulin II. Preconditioned 3- to 4-week-old female NOD mice were transplanted with transduced or nontransduced HSCs and compared with age-matched unmanipulated control. The insulitis, T1D development, and immune reconstitution were assessed. RESULTS: The mean (SD) insulitis score was significantly reduced (1.156 [0.575] vs 2.156 [0.892] or 3.043 [0.728], P = 0.009 or <0.001), and diabetes was nearly completely prevented (1/13 vs 5/12 or 4/9, P = 0.031 or 0.013) in recipients of transduced HSCs expressing proinsulin II as compared with recipients of nontransduced HSCs or unmanipulated control. Sialitis, reconstitution of peripheral blood leukocytes, and in vitro recall responses to ovalbumin were not different between 3 groups of mice. CONCLUSIONS: Syngeneic transplantation of HSCs transduced ex vivo with lentiviral vectors to encode proinsulin II is a novel strategy to prevent T1D.

Interleukin (IL)-22 receptor 1 is over-expressed in primary Sjogren's syndrome and Sjögren-associated non-Hodgkin lymphomas and is regulated by IL-18.

The aim of this study was to elucidate more clearly the role of interleukin (IL)-18 in modulating the IL-22 pathway in primary Sjögren's syndrome (pSS) patients and in pSS-associated lymphomas. Minor salivary glands (MSGs) from patients with pSS and non-specific chronic sialoadenitis (nSCS), parotid glands biopsies from non-Hodgkin lymphomas (NHL) developed in pSS patients, were evaluated for IL-18, IL-22, IL-22 receptor 1 (IL-22R1), IL-22 binding protein (IL-22BP) and signal transducer and activator of transcription-3 (STAT-3) expression. MSGs IL-22R1-expressing cells were characterized by confocal microscopy and flow cytometry in pSS, nSCS and healthy controls . The effect of recombinant IL-18 and IL-22 on peripheral blood mononuclear cells (PBMCs) from pSS and nSCS was studied by flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR). MSGs of pSS and NHL were characterized by an imbalance between IL-22 and IL-22BP protein expression, with IL-18 and IL-22BP being expressed in a mutually exclusive manner and IL-18 and IL-22R1 being correlated directly. Aberrant expression of IL-22R1, induced by IL-18, was observed only among tissue and circulating myeloid cells of pSS patients and macrophages of NHL tissues of pSS patients, but not nSCS. IL-22R1 expression on PBMC of pSS was functional, as its stimulation with recombinant IL-22 significantly up-regulated the expression of STAT-3, IL-17 and IL-22. An IL-18-dependent aberrant expression of IL-22R1 on cells of haematopoietic origin seems to be a specific immunological signature of patients with pSS and pSS-associated lymphomas.

Epigallocatechin gallate stimulates the neuroreactive salivary secretomotor system in autoimmune sialadenitis of MRL-Fas(lpr) mice via activation of cAMP-dependent protein kinase A and inactivation of nuclear factor κB.

The water channel aquaporin 5 (AQP5) plays a crucial role in regulating salivary flow rates. Xerostomia is often observed in patients with Sjögren's syndrome, and this is attributed to reduced AQP5 expression in the salivary glands. Recently, anti-type 3 muscarinic cholinergic receptors (M3R) autoantibodies and nuclear factor κB (NF-κB) have been found to be negative regulators of AQP5 expression in the salivary gland. Anti-M3R autoantibodies desensitize M3R to salivary secretagogues in Sjögren's syndrome, while activated NF-κB translocates to nuclei and binds to the AQP5 gene promoter, resulting in the suppression of AQP5 expression. We previously documented that epigallocatechin gallate (EGCG), which is a robust antioxidant contained in green tea, ameliorates oxidative stress-induced tissue damage to the salivary glands of MRL/MpJ-lpr/lpr (MRL-Fas(lpr)) mice, which are widely used as a model of Sjögren's syndrome. Reactive oxygen species (ROS) can activate NF-κB and inactivate protein kinase A (PKA), which is a key driver of AQP5 expression. In this study, we examined the effects of administering EGCG to MRL-Fas(lpr) mice with autoimmune sialadenitis on the levels of AQP5, activated NF-κB p65 subunit, activated PKA, activated c-Jun N-terminal kinase (JNK) (an activator of NF-κB), inhibitor κB (IκB) and histone deacetylase 1 (HDAC1) (an inhibitor of NF-κB). In EGCG-treated mice, intense aster-like immunostaining for AQP5 was observed on the apical plasma membranes (APMs) of submandibular gland acinar cells. Likewise, PKA, IκB and HDAC1 were highly expressed in salivary gland tissues, whereas the expression of JNK and NF-κB p65 was negligible. Rank correlation and partial correlation analyses revealed that treatment with EGCG upregulated AQP5 expression on the APM of acinar cells through activation of PKA and inactivation of NF-κB, while IκB and HDAC1 played a pivotal role in the induction of AQP5 expression by PKA. Our study indicates that EGCG may have therapeutic potential for Sjögren's syndrome patients.