New Concepts in the Pathogenesis of Sjögren's Syndrome

The circular RNA hsa_circ_0045800 serves as a favorable biomarker in pathogenesis of sjögren's syndrome

BACKGROUND

Circular RNAs (circRNAs) play various roles in the development of many autoimmune diseases. However, their expression profiles and specific function in Sjögren's Syndrome remains largely unknown.

OBJECTIVES

We aimed to investigate circRNAs potential diagnostic value in primary Sjögren's syndrome (pSS) and contribution to the pathogenesis of pSS.

METHODS

This study included 102 subjects, 51 pSS patients and 51 healthy controls. The concentration of hsa_circ_0045800 was analyzed in peripheral blood mononuclear cells obtained from 51 pSS patients and 51 healthy controls by qRT-PCR. We established a receiver operating characteristic curve (ROC) to assess the biological diagnostic value of hsa_circ_0045800 for pSS. In addition, we analyzed the correlation between hsa_circ_0045800 and disease activity in Sjogren's syndrome. A differential analysis was also conducted on the concentration of hsa_circ_0045800 in patients in pSS patients before and after treatment. We studied the downstream mechanism of hsa_circ_0045800 through bioinformatics analysis and confirmed it using luciferase reporter gene assay.

RESULTS

We confirmed that the concentration of hsa_circ_0045800 was elevated 10.4-fold in peripheral blood mononuclear cells of pSS patients than in healthy controls (p = 0.00). In the pSS active disease group, the concentration of hsa_circ_0045800 is 2.5-fold higher compared to the pSS non-active disease group (p = 0.04). The concentration of hsa_circ_0045800 after treatment was decreased by 80% compared with that before treatment (p = 0.037), suggesting its utility as a potential marker for monitoring treatment efficacy. ROC curve analysis showed that the diagnostic value of hsa_circ_0045800 in pSS patients was significantly higher than that in healthy controls, with an area under the curve of 0.865, a sensitivity of 74%, and a specificity of 92%. The concentration of hsa_circ_0045800 is correlated with various clinical factors: the concentration of hsa_circ_0045800 is positively associated with age (r = 0.328, P = 0.019), oral dryness (r = 0.331, P = 0.017), while it is negatively correlated with HGB (r = -0.435, P = 0.001) and and hypothyroidism (r = -0.318, P = 0.023). Bioinformatics predictions and luciferase assays indicated that hsa_circ_0045800 acts as a molecular sponge for miR-1247-5p, with SMAD2 being a target gene of miR-1247-5p.

CONCLUSION

Our study results show that hsa_circ_0045800 potentially contributes to the development and progression of pSS via the miR-1247-5p/SMAD2 pathway. Peripheral blood mononuclear cells are directly involved in the pathogenesis of pSS, and the discovery of hsa_circ_0045800 in peripheral blood mononuclear cells highlights its potential as a novel biomarker for disease activity and diagnosis in patients with pSS. Key Points • The concentration of hsa_circ_0045800 was higher in peripheral blood mononuclear cells of pSS patients. • Hsa_circ_0045800 promoted pSS progression through miR-1247-5p-SMAD2 axis. • Hsa_circ_0045800 is a potential biomarker for pSS.

Carbon quantum dots as immune modulatory therapy in a Sjögren's syndrome mouse model

OBJECTIVES

The objective of the study was to evaluate the therapeutic effects of carbon quantum dots (CQDs) in immunomodulation on non-obese diabetic (NOD) mice, as the model for Sjögren's syndrome (SS).

METHODS

Carbon quantum dots were generated from Setaria viridis via a hydrothermal process. Their toxic effects were tested by cell viability and blood chemistry analysis, meanwhile therapeutic effects were investigated in NOD mice in the aspects of saliva flow, histology, and immune cell distribution.

RESULTS

Carbon quantum dots, with rich surface chemistry and unique optical properties, showed non-cytotoxicity in vitro or no damage in vivo. Intravenously applied CQDs alleviated inflammation in the submandibular glands in NOD mice after 6-week treatments. The inflammatory area index and focus score were significantly decreased in CQD-treated mice. Besides, the levels of anti-SSA and anti-SSB were decreased in the presence of CQDs. The stimulated saliva flow rates and weight of submandibular glands were significantly increased in CQD-treated mice by reducing the apoptosis of cells. The CD3+ and CD4+ T cells distributed around the ducts of submandibular glands were significantly decreased, while the percentage of Foxp3+ cells was higher in CQD-treated mice than that in the control group.

CONCLUSIONS

Our findings suggest that CQDs may ameliorate the dysregulated immune processes in NOD mice.

Exploring the relationship between oxidative stress status and inflammatory markers during primary Sjögren's syndrome: A new approach for patient monitoring

INTRODUCTION

Primary Sjögren's syndrome (pSS) is a chronic inflammatory disease primarily affects exocrine glands dysfunction. Oxidative stress (OS) is a phenomenon occurring as a result of an imbalance between the generation of free radicals and antioxidant defense system. Hence, we aimed to establish the status of OS and inflammatory response according to the pSS disease activity index. In this context, we investigated malondialdehyde (MDA), and antioxidant enzymes during pSS. The possible association between MDA and nitric oxide (NO) levels and between MDA and some pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33).

METHODS

The study has been conducted on 53 pSS patients. The antioxidant enzymes, represented by glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD), were estimated by a colorimetric activity kit. Whereas, MDA value was assessed by measuring thiobarbituric acid reactive substances. Moreover, pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and IL-33) and NO were respectively quantified by enzyme-linked immunosorbent assays (ELISA) and the modified Griess.

RESULTS

Interestingly, we report a notable reduction in our pSS patients' antioxidant enzyme activity, while NO, MDA and proinflammatory cytokines values were significantly increased. pSS patients with higher disease activity had much stronger increases in NO and MDA levels. No significant difference was assessed in CRP level. Additionally, substantial significant correlations between plasmatic NO and MDA levels and between MDA, NO and IL-1β, IL-6, TNF-α cytokines were reported. However, no significant association was found between NO, MDA and IL-33 concentrations.

CONCLUSION

Collectively, our data showed altered oxidant-antioxidant balance in pSS patients. MDA, NO, IL-1β, IL-6, TNF-α seem to be good indicators in monitoring disease activity. Oxidative stress was closely related to inflammation in pSS. Exploiting this relationship might provide valuable indicators in the follow-up and prognosis of pSS with a potential therapeutic value.

Efficacy and safety of platelet-rich plasma and autologous-serum eye drops for dry eye in primary Sjögren's syndrome: a randomized trial

We compared the efficacy and safety of autologous-serum (AS) and platelet-rich plasma (PRP) eye drops for dry eye (DE) treatment in primary Sjögren's syndrome (SS). This prospective, randomized, double-blinded clinical study included patients diagnosed with primary SS DE. Thirty-eight participants were randomly assigned to the AS or PRP groups. Corneal and conjunctival staining scores, Schirmer I test, tear film break-up time (TBUT), and ocular surface disease index (OSDI) scores were evaluated at 4 and 12 weeks. Conjunctival impression cytology (CIC) metaplasia grade and goblet cell density grade at 12 weeks were compared with those at baseline. Corneal and conjunctival staining scores and TBUT significantly improved at 4 and 12 weeks in both groups (all p < 0.005). No significant difference between the AS and PRP groups was observed at 4 and 12 weeks. The Schirmer I values, OSDI scores, CIC metaplasia grade, and goblet cell density grade did not significantly change at 4 and 12 weeks in either group. Both AS and PRP eye drops are effective for primary SS DE without a significant difference. Considering that the preparation time of PRP is shorter than that of AS, PRP can be a good alternative treatment for primary SS DE.

Melatonin: a potential therapeutic approach for the management of primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is an autoimmune disease that primarily affects the exocrine glands and is mainly characterized by sicca symptoms of the eyes and mouth. Approximately 30-50% of pSS patients develop systemic multi-organ disorders including malignant lymphoma. The etiology of pSS is not well understood; growing evidence suggests that uncontrolled immune/inflammatory responses, excessive oxidative stress, defected apoptosis, dysregulated autophagy, exosomes, and exogenous virus infections may participate in the pathogenesis of pSS. There is no ideal therapeutic method for pSS; the management of pSS is mainly palliative, which aims to alleviate sicca symptoms. Melatonin, as the main secretory product of the pineal gland, has been evidenced to show various physiological functions, including effects of immunoregulation, capability of antioxidation, moderation of autophagy, suppressive activities of apoptosis, regulative capacity of exosomes, properties of anti-infection, and improvement of sleep. The beneficial effects of melatonin have been already validated in some autoimmune diseases such as multiple sclerosis (MS), type 1 diabetes mellitus (T1DM), systemic lupus erythematosus (SLE), and inflammatory bowel disease (IBD). However, our previous research firstly revealed that melatonin might inhibit pathogenic responses of peripheral Th17 and double-negative (DN) T cells in pSS. More importantly, melatonin administration alleviated the development of pSS in animal models with reduced infiltrating lymphocytes, improved functional activity of salivary gland, and decreased production of inflammatory factors as well as autoantibodies. Owing to the important biological properties reported in melatonin are characteristics closely related to the treatment of pSS; the potential role and underlying mechanisms of melatonin in the administration of pSS are certainly worth further investigations. Consequently, the aim of this review is to give a deep insight to the therapeutic potency of melatonin for pSS.

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.

Supra-lacrimal protein-based carriers for cyclosporine A reduce Th17-mediated autoimmunity in murine model of Sjögren's syndrome

Sjögren's syndrome (SS) is a multifactorial autoimmune disease with principal symptoms including inflammation and loss of function of lacrimal glands (LG) and salivary glands. While glandular infiltrates includes both B- and T-cells, CD4+ T cells are strongly implicated. Utilizing the male non-obese diabetic (NOD) mouse model of SS, this work: 1) identifies clinically-relevant elevations in cytokines (IL-17A, IL-2) in LG-derived CD4+ T cells; and 2) explores tissue-specific immunosuppression of SS using a novel protein-based drug carrier to concentrate cyclosporine A (CsA) directly in the LG. As a potent immunosuppressant, topical ophthalmic CsA is approved for dry eye disorders; however, it cannot effectively resolve inflammation due to limited accumulation in the LG. Systemic CsA has dose-limiting side effects that also limit its ability to block LG inflammation. Using elastin-like polypeptides (ELPs) fused genetically to cyclophilin, the intracellular cognate receptor of CsA, this manuscript reports a sustained-release formulation of CsA that maintains therapeutic drug concentrations in the LG and extends intervals between doses. This formulation blocked both in vitro Th17 cell differentiation and IL-17A secretion. In vivo treatment significantly decreased the abundance of Th17.1 cells, a helper cell population sharing phenotypes of both Th17 and Th1, in the LG of diseased NOD mice. Treatment with even a single dose of the sustained-release formulation was effective enough to improve basal levels of tear production. Thus, this sustained-release formulation suppressed local LG inflammation driven through IL-17 dependent pathways, while improving ocular surface function.

Specialized pro-resolving receptors are expressed in salivary glands with Sjögren's syndrome

Our previous studies demonstrated that resolvin D1 (RvD1) and its aspirin-trigged (AT) form AT-RvD1, are effective in decreasing inflammation while restoring saliva flow rates in a Sjögren's syndrome (SS)-like mouse model before and after disease onset. Resolvins are specialized pro-resolving mediators (SPM) that actively regulate inflammation. However, we only have extensive data within the salivary glands for RvD1 and AT-RvD1, both of which bind to the receptor ALX/FPR2. As such, the presence of other SPM receptors is unknown within salivary glands. Therefore, the goal of this study was to determine the expression of SPM receptors in non-SS and SS patients. For this purpose, six human minor salivary glands from female subjects were analyzed by H&E using the Chisholm and Mason classification to determine the degree of lymphocytic infiltration. Next, confocal immunofluorescence analysis was performed to determine the presence and distribution of different SPM receptors in mucous acini and striated ducts. We observed diffuse presence of lymphocytic infiltration and clinical data were consistent with SS diagnosis in three patients. Moreover, confocal immunofluorescence analysis indicated the presence of the receptors ALX/FPR2, BLT1 and CMKLR1 in the mucous acini and striated ducts of both non-SS and SS patients. GPR32 was absent in SS and non-SS minor salivary glands. In summary, our results showed that various SPM receptors are expressed in non-SS and SS minor salivary glands, all of which may pose as potential targets for promoting pro-epithelial and anti-inflammatory/pro-resolution signaling on SS patients.

Sjögren's Syndrome and Viral Infections

Sjögren's syndrome (SS) is a systemic autoimmune disease, characterized by lymphocytic infiltration of the secretory glands. This leads to dryness of the main mucosal surfaces such as the mouth, eyes, nose, larynx, pharynx, and vagina. Although there is little morbidity data at the initial diagnosis, SS may be a serious disease, with extra mortality caused by hematological cancer. The cause of SS is unknown, but factors postulated to play a role include genetic and environmental factors, hormonal abnormality, and viral infection. Under the influence of these factors, the immune system becomes abnormal and the tissue is damaged. In this study, we summarize recent developments in our understanding of the relationship between SS and viral infections, including Epstein-Barr virus (EBV), hepatitis C virus (HCV), human T cell lymphotropic virus type 1 (HTLV-1), cytomegalovirus (CMV), and human immunodeficiency virus (HIV).

TAZ inhibits acinar cell differentiation but promotes immature ductal cell proliferation in adult mouse salivary glands

There are currently no treatments for salivary gland diseases, making it vital to understand signaling mechanisms operating in acinar and ductal cells so as to develop regenerative therapies. To date, little work has focused on elucidating the signaling cascades controlling the differentiation of these cell types in adult mammals. To analyze the function of the Hippo-TAZ/YAP1 pathway in adult mouse salivary glands, we generated adMOB1DKO mice in which both MOB1A and MOB1B were TAM-inducibly deleted when the animals were adults. Three weeks after TAM treatment, adMOB1DKO mice exhibited smaller submandibular glands (SMGs) than controls with a decreased number of acinar cells and an increased number of immature dysplastic ductal cells. The mutants suffered from reduced saliva production accompanied by mild inflammatory cell infiltration and fibrosis in SMGs, similar to the Sjogren's syndrome. MOB1-deficient acinar cells showed normal proliferation and apoptosis but decreased differentiation, leading to an increase in acinar/ductal bilineage progenitor cells. These changes were TAZ-dependent but YAP1-independent. Biochemically, MOB1-deficient salivary epithelial cells showed activation of the TAZ/YAP1 and β-catenin in ductal cells, but reduced SOX2 and SOX10 expression in acinar cells. Thus, Hippo-TAZ signaling is critical for proper ductal and acinar cell differentiation and function in adult mice.

Gene expression alterations in salivary gland epithelia of Sjögren's syndrome patients are associated with clinical and histopathological manifestations

Sjögren's syndrome (SS) is a complex autoimmune disease associated with lymphocytic infiltration and secretory dysfunction of salivary and lacrimal glands. Although the etiology of SS remains unclear, evidence suggests that epithelial damage of the glands elicits immune and fibrotic responses in SS. To define molecular changes underlying epithelial tissue damage in SS, we laser capture microdissected (LCM) labial salivary gland epithelia from 8 SS and 8 non-SS controls for analysis by RNA sequencing (RNAseq). Computational interrogation of gene expression signatures revealed that, in addition to a division of SS and non-SS samples, there was a potential intermediate state overlapping clustering of SS and non-SS samples. Differential expression analysis uncovered signaling events likely associated with distinct SS pathogenesis. Notable signals included the enrichment of IFN-γ and JAK/STAT-regulated genes, and the induction of genes encoding secreted factors, such as LTF, BMP3, and MMP7, implicated in immune responses, matrix remodeling and tissue destruction. Identification of gene expression signatures of salivary epithelia associated with mixed clinical and histopathological characteristics suggests that SS pathology may be defined by distinct molecular subtypes. We conclude that gene expression changes arising in the damaged salivary epithelia may offer novel insights into the signals contributing to SS development and progression.

The Association of Serum Vitamin D Level With the Severity of Dry Eye Parameters in Primary Sjögren Syndrome

PURPOSE

To analyze the relationship between serum 25(OH)D3 level and dry eye parameters in primary Sjögren syndrome (SS).

METHODS

This study included 74 eyes of 74 patients diagnosed with primary SS. Dry eye parameters included tear breakup time, Schirmer I value, corneal staining score, conjunctival staining score, and Ocular Surface Disease Index. The serum concentration of 25(OH)D3 was evaluated.

RESULTS

The mean serum 25(OH)D3 level was 20.4 ± 8.0 ng/mL. There were strong negative correlations between serum 25(OH)D3 level and corneal staining score (P < 0.001, r = -0.446) and conjunctival staining score (P < 0.001, r = -0.455). The Schirmer I value and tear breakup time showed significant positive correlations with serum 25(OH)D3 level (P = 0.038, r = 0.261 and P = 0.003, r = 0.352, respectively). The Ocular Surface Disease Index did not show any significant correlation with serum 25(OH)D3 level.

CONCLUSIONS

This study demonstrates that serum 25(OH)D3 level might be associated with dry eye severity in primary SS.

Pathophysiologic role of Interleukin-33/ST2 in Sjögren's syndrome

Interleukin-33 (IL-33) is a member of the IL-1 family and has dual functions as a nuclear factor as well as a cytokine. The pivotal role of IL-33 as an active player contributing to aberrant local and systemic damage has been highlighted in several inflammatory and autoimmune diseases. Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by dry eyes and mouth syndrome due to local dysfunctions of exocrine glands, but also accompanied with systemic manifestations. The pathophysiology of pSS has been advocated as a conjecture of activated B and T cells as well as the production of inflammatory cytokines and autoantibodies, driving epithelial tissue damage and disease progression. In pSS, IL-33 is released in the extracellular space from damaged salivary cells upon pro-inflammatory stimuli and/or dysfunction of epithelial barrier. Counter-regulatory mechanisms are initiated to limit the pro-inflammatory actions of IL-33 as portrayed by an increase in the decoy receptor for IL-33, the soluble form of ST2 (sST2). In pSS and associated diseases, the levels of IL-33 are significantly elevated in the serum or tears of patients. Mechanistically, IL-33 acts in synergy with IL-12 and IL-23 on NK and NKT cells to boost the production of IFN-γ contributing to inflammation. TNF-α, IL-1β and IFN-γ in turn further increase the activation of IL-33/ST2 pathway, thereby constituting a vicious inflammatory loop leading to disease exacerbation. IL-33/ST2 axis is involved in Sjögren's syndrome and opens new perspectives as therapeutic target of one of the culprits in the inflammatory perpetuation.

Childhood Sjogren's syndrome: An Italian case series and a literature review-based cohort

OBJECTIVE

Sjogren's syndrome (SS) is a chronic autoimmune disease with a highly variable presentation. This study aims to describe childhood SS (cSS) features to help guide clinicians in their consideration of and workup for cSS.

METHODS

We retrospectively reviewed medical records of patients with cSS referred to three Italian pediatric rheumatology centers from 2015 to 2019 and we conducted a literature review of cSS. Statistical analysis was performed to detect associations between clinical/laboratory features.

RESULTS

We reviewed 12 cases (9 female) followed in 3 Italian centers and 240 cases (191 female) in the published literature reporting individual information. The median age at disease onset was 10 years for both cohorts. The most frequently reported clinical SS-specific feature was parotitis in both cohorts (67% each). Extraglandular manifestations were very common and joint involvement was the most frequent. In the cluster analysis, we identified a significant association between parotitis and younger patients (< 11 years). We verified the presence of the main SS features (exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies) in the Italian cohort and the literature review-based cohort: 92% and 80% of the cohorts, respectively, had at least 2/3 main characteristics.

CONCLUSION

We described cSS features with relative frequencies and we found that parotid involvement was related to cSS in younger patients. The majority of patients showed various combinations of exocrine gland inflammation, exocrine gland dysfunction, and presence of autoantibodies giving a theoretical basis for future research to pave the way for the development of cSS specific diagnostic criteria.

Current State of Knowledge on Primary Sjögren's Syndrome, an Autoimmune Exocrinopathy

Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune rheumatic disease characterized by lymphoplasmacytic infiltration of the salivary and lacrimal glands, whereby sicca syndrome and/or systemic manifestations are the clinical hallmarks, associated with a particular autoantibody profile. pSS is the most frequent connective tissue disease after rheumatoid arthritis, affecting 0.3-3% of the population. Women are more prone to develop pSS than men, with a sex ratio of 9:1. Considered in the past as innocent collateral passive victims of autoimmunity, the epithelial cells of the salivary glands are now known to play an active role in the pathogenesis of the disease. The aetiology of the "autoimmune epithelitis" still remains unknown, but certainly involves genetic, environmental and hormonal factors. Later during the disease evolution, the subsequent chronic activation of B cells can lead to the development of systemic manifestations or non-Hodgkin's lymphoma. The aim of the present comprehensive review is to provide the current state of knowledge on pSS. The review addresses the clinical manifestations and complications of the disease, the diagnostic workup, the pathogenic mechanisms and the therapeutic approaches.

EBV and CMV viral load in rheumatoid arthritis and their role in associated Sjögren's syndrome

INTRODUCTION

The role of viral infections in the pathogenesis of autoimmune diseases has long been suggested, but little evidence is available.

OBJECTIVE

This study aimed to evaluate an association between EBV and CMV and the presence of rheumatoid arthritis and its association with Sjögren's Syndrome.

PATIENTS AND METHOD

A case-control study was performed with 227 patients divided in RA (n = 99), RA/SS (n = 20), and C (n = 128). Resting salivary flow rate and Schirmer's test were performed; minor salivary gland biopsy was indicated in the case of suspected Sjögren's syndrome. CMV and EBV viral loads were quantified in peripheral blood, and their presence in glandular tissue samples was evaluated by in situ hybridization (EBV) and immunohistochemistry (CMV).

RESULTS

EBV was more frequent in RA and RA/SS than in C (P < .000007). No correlation with clinical markers (P > .05) or between RA and RA/SS was found (P > .05). A higher number of EBV/DNA copies were found in RA (158.52 copies/μL) and RA/SS (99.24 copies/μL) (P = .739). EBV/DNA was associated with the Schirmer test (P = .0231). CMV was detected in one patient of the RA group. None of the viruses were detected in biopsies of minor salivary glands.

CONCLUSIONS

Detection of EBV/DNA in peripheral blood was associated with RA regardless of the presence of SS.

Evaluation of the Efficacy and Safety of A Novel 0.05% Cyclosporin A Topical Nanoemulsion in Primary Sjögren's Syndrome Dry Eye

Purpose: To evaluate the efficacy and safety of a novel topical cyclosporin A 0.05% nanoemulsion in comparison with a conventional emulsion in primary Sjögren's syndrome dry eyes.Methods: Prospective, randomized, double-blinded study was conducted.Results: Corneal and conjunctival staining score was improved in both groups, with a faster change noted in the nanoemulsion group at 12 weeks (p < 0.05). Tear film break-up time was significantly improved in the nanoemulsion group at 12 weeks (p < 0.05), while ocular surface disease index score was improved in both groups without a difference at 12 weeks. Schirmer I value and goblet cell grade did not change in both groups. IL-6 and MMP-9 were significantly decreased in both groups at 12 weeks.Conclusions: Both nanoemulsion and conventional cyclosporin A improved ocular signs, symptoms, and conjunctival inflammation. However, the novel cyclosporin A nanoemulsion showed faster improvement of ocular surface staining scores than the conventional emulsion.

Comparison of Meibomian Gland Imaging Findings and Lipid Layer Thickness between Primary Sjögren Syndrome and Non-Sjögren Syndrome Dry Eyes

Purpose: To compare meibomian gland (MG) imaging findings and lipid layer thickness (LLT) between patients with primary Sjögren syndrome (SS) dry eyes (DE) and non-SS DE.Methods: A total of 60 patients-30 with SS DE and 30 with non-SS DE were evaluated. Infrared image findings of MGs and LLT were assessed using the LipiView II interferometer.Results: The maximum LLT was significantly lower in the SS DE group. SS DE exhibited significantly higher MG dropout compared to the non-SS DE. Average and maximal LLT showed significant negative correlations with MG dropout in both groups (p<0.05). Conjunctival staining scores showed significant correlations with average and maximum LLT and MG dropout values in the SS DE group (p<0.05).Conclusion: These findings suggest that the new interferometer will be useful in understanding the pathophysiology of SS DE.

Salivary adiponectin, but not adenosine deaminase, correlates with clinical signs in women with Sjögren's syndrome: a pilot study

OBJECTIVES

To evaluate salivary adiponectin and adenosine deaminase (ADA) in women suffering from Sjögren's syndrome (SS).

METHODS

Salivary adiponectin and ADA were measured in patients with SS (n = 17) and compared to their values in healthy controls (n = 13) and patients suffering from drug-induced xerostomia (non-SS sicca group; n = 19). A clinical history was made for each patient, patients were examined clinically, and xerostomia inventory (XI) was performed.

RESULTS

Salivary adiponectin corrected by total protein was higher in patients with SS than in healthy individuals (P < 0.05) or patients with non-SS sicca (P < 0.01) and correlated with XI (r = 0.555; P < 0.05). Salivary ADA was higher in patients with SS and non-SS sicca compared to controls (P < 0.05 in both cases).

CONCLUSION

The results of the present study indicate that adiponectin and ADA are increased in the saliva of patients with SS.

CLINICAL RELEVANCE

Salivary adiponectin corrected by total protein can be a potential biomarker of SS.

TRIAL REGISTRATION

NCT03156569.

Detection of salivary protein biomarkers of saliva secretion disorder in a primary Sjögren syndrome murine model

Saliva secretion disorder is one of the most common symptoms in primary Sjögren syndrome (pSS). Salivary biomarkers related to saliva secretion disorder were identified in a pSS murine model, NOD/ShiLtJ mouse, using differential proteomic analysis. Candidate biomarkers were screened with Kyoto Encyclopedia of Genes and Genomes pathway analysis and validated in saliva and salivary glands by western blotting and immunohistochemistry (IHC). Biological functions were detected using ingenuity pathway analysis (IPA). We identified 1101 salivary proteins from NOD/ShiLtJ mice and BALB/c mice (control). Catenin alpha-3 (CTNNA3), tyrosine-protein phosphatase non-receptor type 6 (PTPN6), Ras-related C3 botulinum toxin substrate (RAC2), and intermediate conductance calcium-activated potassium channel protein 4 (KCNN4) were screened as candidate biomarkers from 225 significantly dysregulated salivary proteins. These proteins participated in adherens junction or saliva secretion pathway and may be related to saliva secretion disorder. Proteomic analysis revealed that CTNNA3, PTPN6, and RAC2 were dysregulated in saliva and salivary glands and showed satisfactory sensitivity and specificity in receiver-operating characteristic curve; KCNN4 showed no statistical difference. IHC and IPA indicated that CTNNA3 may regulate acinar cell morphology, while PTPN6 and RAC2 promoted lymphocyte adhesion in salivary glands. Thus, CTNNA3, PTPN6, and RAC2 may be related to saliva secretion disorder in pSS.

Elevation of autophagy markers in Sjögren syndrome dry eye

Autophagy is known to be implicated in the pathogenesis of Sjögren syndrome (SS), but evidences are limited. We aimed to examine the levels of autophagy markers in tear film and conjunctival epithelial cells from SS dry eye patients, and analyze their correlations with clinical features. Patients with SS dry eye exhibited lower Schirmer values, lower tear breakup time, and higher ocular staining scores. In tears, ATG5 and LC3B-II/I levels were significantly higher in SS dry eye. ATG5 and LC3B-II mRNA in the conjunctiva were also elevated in SS dry eye compared with non-SS dry eye. The immunostaining of conjunctival epithelium showed a punctate pattern of ATG5 and LC3B-II in SS dry eye. These staining patterns were also observed in the lacrimal gland of SS animal models. ATG5 levels in tears and the conjunctival epithelium strongly correlated with ocular staining scores, and one month of topical corticosteroid treatment reduced both ATG5 and LC3B-II/I levels in tear film and the conjunctival epithelium of patients with SS dry eye. Our results suggest that autophagy is enhanced or dysregulated in SS and autophagy markers may be serve as both diagnostic and therapeutic biomarkers in SS dry eye.

Clinical evaluation of a nutraceutical diet as an adjuvant to pharmacological treatment in dogs affected by Keratoconjunctivitis sicca

Background

Canine keratoconjunctivitis sicca (cKCS) is an inflammatory eye condition related to a deficiency in the tear aqueous fraction. Etiopathogenesis of such disease is substantially multifactorial, combining the individual genetic background with environmental factors that contribute to the process of immunological tolerance disruption and, as a consequence, to the emergence of autoimmunity disease. In this occurrence, it is of relevance the role of the physiological immune-dysregulation that results in immune-mediated processes at the basis of cKCS. Current therapies for this ocular disease rely on immunosuppressive treatments. Clinical response to treatment frequently varies from poor to good, depending on the clinical-pathological status of eyes at diagnosis and on individual response to therapy. In the light of the variability of clinical response to therapies, we evaluated the use of an anti-inflammatory/antioxidant nutraceutical diet with potential immune-modulating activity as a therapeutical adjuvant in cKCS pharmacological treatment. Such combination was administered to a cohort of dogs affected by cKCS in which the only immunosuppressive treatment resulted poorly responsive or ineffective in controlling the ocular symptoms.

Results

Fifty dogs of different breeds affected by immune-mediated cKSC were equally distributed and randomly assigned to receive either a standard diet (control, n = 25) or the nutraceutical diet (treatment group, n = 25) both combined with standard immunosuppressive therapy over a 60 days period. An overall significant improvement of all clinical parameters (tear production, conjunctival inflammation, corneal keratinization, corneal pigment density and mucus discharge) and the lack of food-related adverse reactions were observed in the treatment group (p < 0.0001).

Conclusions

Our results showed that the association of traditional immune-suppressive therapy with the antioxidant/anti-inflammatory properties of the nutraceutical diet resulted in a significant amelioration of clinical signs and symptoms in cKSC. The beneficial effects, likely due to the presence of supplemented nutraceuticals in the diet, appeared to specifically reduce the immune-mediated ocular symptoms in those cKCS-affected dogs that were poorly responsive or unresponsive to classical immunosuppressive drugs. These data suggest that metabolic changes could affect the immune response orchestration in a model of immune-mediated ocular disease, as represented by cKSC.

Resveratrol improves salivary dysfunction in a non-obese diabetic (NOD) mouse model of Sjögren's syndrome

Resveratrol is a natural polyphenol produced by plants in response to environmental stress. This compound has been shown to have pharmacological effects against a wide range of diseases including neurological, hepatic, cardiovascular and autoimmune conditions. The non-obese diabetic (NOD) mouse, in which loss of lacrimal and salivary gland function occurs, has been studied as an animal model for Sjögren’s syndrome. In this study, we confirmed that administration of resveratrol results in increased secretion of saliva in NOD mice. Although resveratrol enhanced Sirt1 activity, inflammatory cell infiltration was not affected. Moreover, expression of the anti-inflammatory cytokine IL-10 in salivary glands was enhanced in the resveratrol-administered group. Thus, we confirmed a novel therapeutic effect for resveratrol on salivary dysfunction in Sjögren’s syndrome.

Periodontitis prevalence and serum antibody reactivity to periodontal bacteria in primary Sjögren's syndrome: a pilot study

AIMS

The aims of this study were as follows: (i) To assess the prevalence of periodontitis among patients with primary Sjögren's syndrome (pSS) and comparator groups of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). (ii) To perform a pilot study to compare serum antibody responses to 10 oral/periodontal bacteria in these patient groups and a historical comparator group of patients with periodontitis.

MATERIALS AND METHODS

Standard clinical periodontal assessments were performed on 39 pSS, 36 RA and 23 OA patients and "In-house" antibody ELISAs for serum antibodies against 10 oral/periodontal bacteria were performed in these groups.

RESULTS

Forty-six percent of the pSS group, 64% of the RA group and 48% of the OA group had moderate/severe periodontitis. These frequencies did not reach statistical significance between groups. Raised antibody levels to Prevotella denticola were found in the pSS, RA and periodontitis groups compared to the OA group. Significant between group differences were seen for Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Campylobacter showae. None of these differences were specifically associated with pSS.

CONCLUSION

This study showed no increase in periodontitis in pSS patients. Although the P. denticola data are of interest, identifying bacterial triggering factors for pSS will likely require alternative strategies including modern techniques such as microbiome analysis.

High fidelity between saliva proteomics and the biologic state of salivary glands defines biomarker signatures for primary Sjögren's syndrome

OBJECTIVE

Dependence on invasive procedures for classification of patients with Sjögren's syndrome (SS) hampers timely diagnosis and suitable patient followup. The aim of this study was to recapitulate the diagnosis of SS through noninvasive means and to define the biologic state of SS patients' salivary glands.

METHODS

Using a 187-plex capture antibody-based assay, salivary proteomic biomarker profiles were generated from patients with primary SS, patients with rheumatoid arthritis, and asymptomatic controls. Discriminant function analyses and Gene Ontology-based network analyses allowed data analyses with a reductionist approach and with a focus on systems biology.

RESULTS

Characterized by significant changes in 61 and 55 proteins, respectively, the salivary proteome of SS patients appeared profoundly altered compared to that of individuals without SS. On this basis, 4-plex and 6-plex biomarker signatures, both including interleukin-4 (IL-4), IL-5, and clusterin, achieved accurate prediction of an individual's group membership for at least 94% of cases. Of note, all misclassified SS patients presented with ectopic germinal center-like structures. Systematic inference of biologic meaning identified SS-related protein patterns delineating B cell-dominated immune responses, macrophage differentiation, and signs of T cell chemotaxis. In addition, proteomic Multi-Analyte Profiles provided insight about proteins related to collagen, cytokine, and growth factor synthesis as well as lipid transport.

CONCLUSION

The SS-related molecular landscape conveyed by saliva showed great congruence with histopathologic features found in SS and advances understanding of this disease at a molecular level. Such salivary biomarker signatures harbor great potential for improving timeliness of SS diagnosis and enabling suitable patient followup.

Calcium signaling and cell volume regulation are altered in Sjögren's Syndrome

OBJECTIVE

Sjögren's Syndrome (SS) is a chronic autoimmune disease, leading to deficient secretion from salivary and lacrimal glands. Saliva production is normally increased by cholinergic innervation, giving rise to intracellular calcium signaling and water transport through water channels (aquaporins, AQPs). The aim of this study was to investigate possible pathophysiological changes in cell volume regulation, AQP expression and localization, and intracellular calcium signaling in glandular cells from SS patients compared to controls.

MATERIALS AND METHODS

A total of 35 SS patients and 41 non-SS controls were included. Real time qPCR was combined with immunohistochemistry to analyze the mRNA expression and cellular distribution of AQP1, 3 and 5. Cell volume regulation and intracellular calcium signaling were examined in fresh acinar cells.

RESULTS

We show for the first time a reduced mRNA expression of AQP1 and 5 in SS compared to controls, accompanied by a decrease in staining intensity of AQP1, 3 and 5 in areas adjacent to local lymphocytic infiltration. Furthermore, we observed that the SS cells' capacity for volume regulation was abnormal. Similarly, the calcium response after parasympathetic agonist (carbachol) stimulation was markedly decreased in SS cells.

CONCLUSIONS

It is concluded that mRNA expression of AQP1 and 5, protein distribution of AQP1, 3 and 5, glandular cell volume regulation and intracellular calcium signaling are all altered in SS, pointing to possible pathophysiological mechanisms in SS.

Clinical and laboratorial profile and histological features on minor salivary glands from patients under investigation for Sjögren's syndrome

Diagnosis of Sjögren’s syndrome (SS) is complex and the usefulness of labial minor salivary glands biopsy in this process remains controversial. Objectives: to evaluate the clinical and laboratorial profile and histological features on labial minor salivary glands from patients under investigation of SS. Study Design: clinical charts from 38 patients under suspicion of SS and submitted to labial minor salivary glands biopsies were reviewed. Clinical and laboratorial data were retrieved from the clinical files and the HE-stained histological slides were reviewed under light microscopy. Results: mean age of the patients was 56.5 years and 97% were females; histological analysis showed that 42% of the cases showed ductal dilatation, lymphocytic foci were found in 52.6% and, from this group, 80% of the cases presented a foci/lobules ratio above 0.8. Acinar/ductal ratio was considered diminished in 39.5% of the samples. Thirty six (95%) and 32 (84%) patients, respectively, complained about xerostomia and xerophthalmia. A study of the time interval of the symptoms that led to SS investigation showed a mean of 116 months. Moreover, sixty-six percent of the patients had already been submitted to immunosuppressive therapy prior to the labial minor salivary gland biopsy. Age of the patients, scintigraphic alterations on salivary function, antinuclear factor (ANF), anti-Ro and anti-La did not show statistical significant association with the histological features. Lobules/foci ratio above 0.8 was the only histological parameter statistically associated with Sjögren’s syndrome diagnosis (p<0.0001). Conclusions: in the studied sample, lymphocytic foci on salivary glands were the only histological parameter associated to the diagnosis of SS. Early indication of labial minor salivary gland biopsy to patients under investigation of SS could limit the effects of immunosuppressive therapy on the histological features associated with the evolution of salivary gland involvement in SS.

Key words:Sjögren syndrome, minor salivary glands, biopsy, lymphocytic foci.

NCR3/NKp30 contributes to pathogenesis in primary Sjogren's syndrome

Primary Sjögren's syndrome (pSS) is a chronic autoimmune disease characterized by a lymphocytic exocrinopathy. However, patients often have evidence of systemic autoimmunity, and they are at markedly increased risk for the development of non- Hodgkin's lymphoma. Similar to other autoimmune disorders, a strong interferon (IFN) signature is present among subsets of pSS patients, although the precise etiology remains uncertain. NCR3/NKp30 is a natural killer (NK)-specific activating receptor regulating the cross talk between NK and dendritic cells and type II IFN secretion. We performed a case-control study of genetic polymorphisms of the NCR3/NKp30 gene and found that rs11575837 (G>A) residing in the promoter was associated with reduced gene transcription and function as well as protection to pSS. We also demonstrated that circulating levels of NCR3/NKp30 were significantly increased among pSS patients compared with controls and correlated with higher NCR3/NKp30 but not CD16-dependent IFN-γ secretion by NK cells. Excess accumulation of NK cells in minor salivary glands correlated with the severity of the exocrinopathy. B7H6, the ligand of NKp30, was expressed by salivary epithelial cells. These findings suggest that NK cells may promote an NKp30-dependent inflammatory state in salivary glands and that blockade of the B7H6/NKp30 axis could be clinically relevant in pSS.

The Hippo signaling pathway is required for salivary gland development and its dysregulation is associated with Sjogren's syndrome

Sjogren's syndrome (SS) is a complex autoimmune disease that primarily affects salivary and lacrimal glands and is associated with high morbidity. Although the prevailing dogma is that immune system pathology drives SS, increasing evidence points to structural defects, including defective E-cadherin adhesion, to be involved in its etiology. We have shown that E-cadherin has pivotal roles in the development of the mouse salivary submandibular gland (SMG) by organizing apical-basal polarity in acinar and ductal progenitors and by signaling survival for differentiating duct cells. Recently, E-cadherin junctions have been shown to interact with effectors of the Hippo signaling pathway, a core pathway regulating the organ size, cell proliferation, and differentiation. We now show that Hippo signaling is required for SMG-branching morphogenesis and is involved in the pathophysiology of SS. During SMG development, a Hippo pathway effector, TAZ, becomes increasingly phosphorylated and associated with E-cadherin and α-catenin, consistent with the activation of Hippo signaling. Inhibition of Lats2, an upstream kinase that promotes TAZ phosphorylation, results in dysmorphogenesis of the SMG and impaired duct formation. SMGs from non-obese diabetic mice, a mouse model for SS, phenocopy the Lats2-inhibited SMGs and exhibit a reduction in E-cadherin junctional components, including TAZ. Importantly, labial specimens from human SS patients display mislocalization of TAZ from junctional regions to the nucleus, coincident with accumulation of extracellular matrix components, fibronectin and connective tissue growth factor, known downstream targets of TAZ. Our studies show that Hippo signaling has a crucial role in SMG-branching morphogenesis and provide evidence that defects in this pathway are associated with SS in humans.

Analysis of tear cytokines and clinical correlations in Sjögren syndrome dry eye patients and non-Sjögren syndrome dry eye patients

PURPOSE

To compare concentrations of tear cytokines in 3 groups composed of Sjögren syndrome (SS) dry eye, non-Sjögren syndrome (non-SS) dry eye, and normal subjects. Correlations between ocular surface parameters and tear cytokines were also investigated.

DESIGN

Prospective cross-sectional study.

METHODS

SS dry eye patients (n = 24; 40 eyes) were diagnosed with primary SS according to the criteria set by the American-European Consensus Group. Non-SS dry eye patients (n = 25; 40 eyes) and normal subjects (n = 21; 35 eyes) were also enrolled. Tear concentrations of interleukin (IL)-17, IL-6, IL-10, IL-4, IL-2, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α) were measured by a multiplex immunobead assay. Ocular Surface Disease Index (OSDI), tear film breakup time (TBUT), Schirmer I test, and fluorescein staining scores were obtained from dry eye patients.

RESULTS

All cytokine levels except for IL-2 were highest in the SS group, followed by non-SS dry eye group and control subjects. Concentrations of IL-17, TNF-α, and IL-6 were significantly different among the 3 groups (IL-17: SS > control P < .001, non-SS > control P = .042, SS > non-SS P < .001; TNF-α: SS > control P = .006, non-SS > control P = .034, SS > non-SS P = .029; IL-6: SS > control P = .002, non-SS > control P = .032, SS > non-SS P = .002). IL-17 was significantly correlated with TBUT (R = -0.22, P = .012) and Schirmer I test (R = -0.36, P = .027) scores in the SS group. IL-6 was significantly correlated only with TBUT (R = -0.38, P = .02) in the non-SS group.

CONCLUSIONS

Differences in tear cytokine levels and correlation patterns between SS dry eye and non-SS dry eye patients suggest the involvement of different inflammatory processes as causes of dry eye syndrome.

Type I interferons in Sjögren's syndrome

Sjögren's syndrome is a chronic autoimmune disease characterized by lymphocytic infiltration of the salivary and lachrymal glands resulting in dry eyes and mouth. Genetic predisposition, pathogenic infections and hormones have been implicated in the pathogenesis of the disease. Studies in the last several years have revealed marked over-expression of the type I interferon (IFN)-inducible genes in the peripheral blood and salivary glands of patients with Sjögren's syndrome. The expression of the type I IFN-inducible genes in Sjögren's syndrome also positively correlates to titers of anti-Ro and anti-La autoantibodies, which are typical for this disease. Plasmacytoid dendritic cells (pDC) are the major source of type I IFN production and activated pDC are detected in minor salivary gland biopsies from patients with primary Sjögren's syndrome. In addition, polymorphisms in genes important both for the production and response to type I IFN are associated to increased risk for Sjögren's syndrome. Because type I IFN bears a variety of biological functions, such as defense against viral infections and activation of the immune system, these results suggest that the type I IFN system has an important role in the pathogenesis of Sjögren's syndrome. A variety of mechanisms causing an activation of the type I IFN system are discussed in this review. Given the pivotal role of type I IFN in the disease process, therapeutic interventions targeting the type I IFN signaling pathway have the potential to benefit the patients with elevated type I IFN status and such hypothesis needs to be carefully evaluated in clinical development.

STIM1 and STIM2 protein deficiency in T lymphocytes underlies development of the exocrine gland autoimmune disease, Sjogren's syndrome

Primary Sjögren's Syndrome (pSS) is an autoimmune disease involving salivary and other exocrine glands that leads to progressive lymphocytic infiltration into the gland, tissue damage, and secretory defects. The mechanism underlying this disease remains poorly understood. Here we report that mice with T-cell-targeted deletion of Stromal Interaction Molecule (STIM) 1 and STIM2 [double-knockout (DKO)] mice develop spontaneous and severe pSS-like autoimmune disease, displaying major hallmarks of the disease. In DKO mice, diffuse lymphocytic infiltration was seen in submandibular glands, a major target of pSS, by age 6 wk, progressing to severe inflammation by age 12 wk. Sjögren's syndrome-specific autoantibodies (SSA/Ro and SSB/La) were detected in the serum, and progressive salivary gland destruction and loss of fluid secretion were also seen. Importantly, we report that peripheral blood mononuclear cells as well as lymphocytic infiltrates in submandibular glands from patients with pSS demonstrated significant reductions in STIM1 and STIM2 proteins. Store-operated calcium entry was also reduced in peripheral blood mononuclear cells from pSS patients compared with those from healthy controls. Thus, deficiency of STIM1 and STIM2 proteins in T cells, and consequent defects in Ca(2+) signaling, are associated with salivary gland autoimmunopathy in DKO mice and pSS patients. These data reveal a previously unreported link between STIM1 and STIM2 proteins and pSS.

Proteomic analysis of saliva: a unique tool to distinguish primary Sjögren's syndrome from secondary Sjögren's syndrome and other sicca syndromes

Introduction

A growing interest has arisen in salivary proteomics as a tool for the identification of biomarkers for primary Sjögren's syndrome (pSS). Nonetheless, only a limited number of preclinical validation studies have been performed, limiting the possibility of translating proteomic results into clinical practice. The primary aim of this study was to refine the diagnostic power of a panel of candidate salivary biomarkers described in pSS with respect to both healthy volunteers and pathological controls. We also explored the pathogenetic function of the detected putative biomarkers both in the local exocrinopathy and in the systemic inflammatory processes of SS.

Methods

One hundred and eighty patients were included in the study overall. In the first "exploratory phase", we enrolled 40 females with pSS, 40 sex- and age-matched healthy volunteers, 10 patients with sicca non-SS and 15 secondary SS (sSS) patients. The testing cohort of the second "challenge phase" of the study was represented by 75 unselected, consecutive subjects: 19 pSS, 21 healthy volunteers, 10 sicca non-SS and 25 sSS patients. Salivary proteomic analysis was performed combining two-dimensional electrophoresis (2DE) and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Western blot (WB) analysis and enzyme-linked immunosorbent assay (ELISA) were employed to validate 2DE results. Ingenuity Pathway Analysis (IPA) Knowledge base was adopted to associate candidate biomarkers in a signalling pathogenetic network.

Results

A total of 28, 6, 7 and 12 protein spots were found to be significantly different in pSS samples with respect to healthy volunteers, non-SS sicca syndrome, SSc-sSS and rheumatoid arthritis-sSS, leading to the identification of 15 differently expressed proteins. Among them, α-amylases precursor, carbonic anhydrase VI, β-2 microglobulin, glyceraldehydes-3-phosphate dehydrogenase (G3PDH), epidermal fatty acid binding protein (E-FABP) and immunoglobulin k light chain (IGK-light chain) apparently showed the most significant differences in pSS when compared to healthy volunteers and non-SS pathological controls. On the other hand, as expected, pSS and sSS salivary profiles shared a great number of similarities.

Conclusions

This study demonstrated that salivary fluid might represent a novel ideal milieu for the detection of a diagnostic panel of candidate biomarkers for pSS, and to gain an insight into the pathogenetic processes underlying glandular and systemic autoimmune disorders.

Decreased salivary sulphotransferase activity correlated with inflammation and autoimmunity parameters in Sjogren's syndrome patients

OBJECTIVES

To determine the expression and enzymatic activities of sulphotransferases involved in mucin hyposulphation in labial salivary glands (LSGs) from SS patients and to correlate sulphotransferase activity with clinical parameters such as secretion, inflammation and serology.

METHODS

LSG from 31 SS patients and 31 control subjects were studied. Relative mRNA and protein levels of Gal3-O-sulphotransferases (Gal3STs) and β1,3-galactosyltransferase-5 (β3GalT5) were determined by quantitative RT-PCR and western blotting, respectively. Enzymatic activities were quantified using radioactively labelled donor substrates and specific acceptor substrates. Products were purified by chromatography. Spearman's correlation analysis was used to compare data.

RESULTS

The levels of Gal3ST activity were significantly decreased in SS patients, without changes in mRNA and protein levels, while the enzymatic activities of glycosyltransferases involved in mucin glycosylation were similar in both groups. An inverse correlation was observed between Gal3ST activity and glandular function measured by scintigraphy, but not with unstimulated salivary flow. Gal3ST activity was inversely correlated with focus score, TNF-α levels and presence of the autoantibodies Ro/SS-A and La/SS-B.

CONCLUSION

The decrease in sulphotransferase activity provides an explanation for mucin hyposulphation observed in the LSGs from SS patients. The decrease in Gal3STs activity was not a consequence of reduced gene expression, but probably due to alterations in the enzyme activity regulation. Interestingly, the levels of sulphotransferase activity detected correlated well with secretory function, inflammation and serology. Finally, we postulate that pro-inflammatory cytokines induced by autoantibodies, such as Ro/SS-A and La/SS-B in SS patients, may modulate Gal3ST activity, thereby altering mucin quality and leading to mouth dryness.

Gene expression profiling of early-phase Sjögren's syndrome in C57BL/6.NOD-Aec1Aec2 mice identifies focal adhesion maturation associated with infiltrating leukocytes

PURPOSE

Despite considerable efforts, the molecular and cellular events in lacrimal gland tissues initiating inflammatory responses leading to keratoconjunctivitis sicca (KCS), autoimmunity, and Sjögren's syndrome (SjS) have yet to be defined. To determine whether altered glandular homeostasis occurs before the onset of autoimmunity, a temporal transcriptome study was carried out in an animal model of primary SjS.

METHODS

Using oligonucleotide microarrays, gene expression profiles were generated for lacrimal glands of C57BL/6.NOD-Aec1Aec2 mice 4 to 20 weeks of age. Pairwise analyses identified genes differentially expressed, relative to their 4-week expression, during the development of SjS-like disease. Statistical analyses defined differentially and coordinately expressed gene sets. The PANTHER (Protein ANalysis THrough Evolutionary Relationships) classification system was used to define annotated biological processes or functions.

RESULTS

Temporal transcript expression profiles of C57BL/6.NOD-Aec1Aec2 lacrimal glands before, or concomitant with, the first appearance of inflammatory cells revealed a highly restricted subset of differentially expressed genes encoding interactive extracellular matrix proteins, fibronectin, integrins, and syndecans. In contrast, genes encoding interepithelial junctional complex proteins defined alterations in tight junctions (TJ), adherens, desmosomes, and gap junctions, suggesting perturbations in the permeability of the paracellular spaces between epithelial barriers. Correlating with this were gene sets defining focal adhesion (FA) maturation and Ras/Raf-Mek/Erk signal transduction. Immunohistochemically, FAs were associated with infiltrating leukocytes and not with lacrimal epithelial cells.

CONCLUSIONS

For the first time, FA maturations are implicated as initial biomarkers of impending autoimmunity in lacrimal glands of SjS-prone mice. Changes in TJ complex genes support an increased movement of cells through paracellular spaces.

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.

Peripheral nervous system manifestations of Sjögren syndrome: clinical patterns, diagnostic paradigms, etiopathogenesis, and therapeutic strategies

Sjögren syndrome is among the most common autoimmune diseases affecting adults in the United States, and is frequently regarded as an immune-mediated exocrinopathy exclusively causing dry eyes and dry mouth. However, as a systemic rheumatic disease, there can be various "extraglandular" complications. The eclectic permutation of peripheral nervous system (PNS) syndromes which occur in Sjögren patients are among the most common and severe extraglandular complications. This review article highlights the evaluation, differential diagnosis, immunopathogenic mechanisms, and potential treatment options of these PNS complications encountered by neurologists. The sensory neuropathies constitute the most frequent PNS complication. Sjögren patients can suffer from severe neuropathic pain, with small-fiber neuropathy causing lancinating or burning pain which can disproportionately affect the proximal torso or extremities, and the face (ie, in a "non-length-dependent distribution"). The technique of skin biopsy, assessing for the intraepidermal nerve fiber density of unmyelinated nerves, provides a useful technique for neurologists to diagnose small-fiber neuropathies, especially when there is such a non-length-dependent distribution. Other diagnostic techniques (ie, electromyography/nerve-conduction studies, evoked potentials, nerve and muscle biopsy) may be useful in specific subtypes of neuropathies. A rational approach to treatment requires a careful appraisal of the clinical subtype of the neuropathy, as well as a familiarity with such discriminating immunopathogenic mechanisms. The application of the traditional armamentarium used for neuropathic pain can be especially challenging. Sjögren patients can suffer from debilitating fatigue, sicca symptoms, and autonomic findings; as such manifestations can be complications of various neuropathic agents, neurologists should understand how to minimize such iatrogenic complications. Therefore, this article will empower neurologists to more effectively collaborate with rheumatologists, in the diagnosis and treatment of Sjögren patients with PNS complications.