Suppression of tumor necrosis factor alpha-induced matrix metalloproteinase 9 production by the introduction of a super-repressor form of inhibitor of nuclear factor kappaBalpha complementary DNA into immortalized human salivary gland acinar cells. Prevention of the destruction of the acinar structure in Sjögren's syndrome salivary glands

Emerging biologic frontiers for Sjogren's syndrome: Unveiling novel approaches with emphasis on extra glandular pathology

Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by exocrine gland dysfunction, leading to dry eyes and mouth. Despite growing interest in biologic therapies for pSS, FDA approval has proven challenging due to trial complications. This review addresses the absence of a molecular-target-based approach to biologic therapy development and highlights novel research on drug targets and clinical trials. A literature search identified potential pSS treatment targets and recent advances in molecular understanding. Overlooking extraglandular symptoms like fatigue and depression is a notable gap in trials. Emerging biologic agents targeting cytokines, signal pathways, and immune responses have proven efficacy. These novel therapies could complement existing methods for symptom alleviation. Improved grading systems accounting for extraglandular symptoms are needed. The future of pSS treatment may involve gene, stem-cell, and tissue-engineering therapies. This narrative review offers insights into advancing pSS management through innovative biologic interventions.

Regulation of MMP9 transcription by ETS1 in immortalized salivary gland epithelial cells of patients with salivary hypofunction and primary Sjögren's syndrome

Primary Sjögren’s syndrome (pSS) patients exhibit enhanced degradation of the salivary epithelium initially through MMP9 overexpression. We assessed the expression of MMP9 and an associated transcription factor, ETS1, in primary salivary gland epithelial cells (SGECs) and investigated potential regulatory mechanism(s) in immortalized SGECs. SGECs and iSGECs were derived from pSS and/or xerostomic “sicca” patients. siRNA knockdown of ETS1 in iSGECs was performed to determine MMP9 mRNA (qRT-PCR) and protein expression (ELISA). ETS1 binding to MMP9 promoter was assessed by luciferase activity and binding confirmed by mutagenesis and ChIP. Effects of ETS1 overexpression on progenitor and Epithelial-Mesenchymal transition (EMT) associated markers were determined by Western blot. Expression of ETS1 and its phosphorylated form in iSGECs was determined by immunofluorescence microscopy. ETS1 and MMP9 were overexpressed in SGECs of pSS and non-pSS sicca patients with salivary gland lymphocytic infiltration compared to non-pSS sicca patients without infiltration. ETS1 siRNA knockdown reduced both MMP9 mRNA and protein levels. ETS1 overexpression affected the expression of EMT and progenitor cell markers. Lastly, ETS1 bound the MMP9 promoter within the DNA region of −296 bp to −339 bp. ETS1 may impair salivary function through direct transcriptional control of the MMP9 promoter. ETS1 upregulation may also affect other factors involved in repair of the dysfunctional pSS salivary epithelium.

Biologic therapy in Sjögren's syndrome

Sjögren's syndrome (SS) is a chronic autoimmune disease with complex and diverse clinical manifestations. It is characterized by lymphocyte infiltration of exocrine glands such as the salivary gland and lacrimal gland leading to insufficient secretion of the gland, manifested as dry mouth and dry eyes. In addition, it can involve extraglandular organs and cause systemic damage. The pathogenesis of SS is still unclear. At present, symptomatic treatment is the mainstay and there is a lack of effective therapy. With the development of molecular pathways underlying the pathogenesis of SS, more and more novel biological agents are used to treat SS. We summarized and analyzed the existing evidences on the efficacy of biological treatment of SS and their targets. Analysis of the efficacy of biological therapy and improvement of treatment strategies can help to give full play to its therapeutic advantages.

MMP-9 Inhibition Suppresses Interferon-γ-Induced CXCL10 Production in Human Salivary Gland Ductal Cells

Gene expression profiling of lip salivary gland (LSG) has shown that C-X-C motif chemokine 10 (CXCL10) and matrix metalloproteinase 9 (MMP9) expression is upregulated in primary Sjögren's syndrome (pSS) patients. Although CXCL10 and MMP-9 are both associated with pSS pathogenesis, the potential relationship between these two factors has not been investigated. In this study, we used LSG sections from pSS patients and human salivary gland cell lines to investigate the relationship between CXCL10 and MMP-9. Immunofluorescence analyses revealed that CXCL10 and MMP-9 were co-expressed in the LSG of pSS patients, particularly in expanded ductal cells. Furthermore, RT-qPCR analyses on human salivary gland ductal NS-SV-DC cells confirmed that CXCL10 expression was induced by interferon (IFN)-γ, whereas that of MMP9 was stimulated by IFN-α, tumor necrosis factor-α, and interleukin-1β. Remarkably, MMP-9 inhibition in IFN-γ-stimulated NS-SV-DC cells significantly decreased CXCL10 mRNA and secreted protein levels. Further analyses established that MMP-9 inhibition in IFN-γ-stimulated NS-SV-DC cells decreased STAT1 phosphorylation and hence suppressed IFN-γ signaling. Collectively, these results suggest that in addition to its reported role in the destruction of acinar structures, MMP-9 is involved in the IFN-γ-induced production of CXCL10 in pSS lesions. We believe that our findings open the door to the development of novel treatments for pSS, based on the modulation of MMP-9 activity.

Differential immunohistochemical expression of type I collagen and matrix metalloproteinase 2 among major salivary glands of young and geriatric mice

Objective

This study aimed to demonstrate the immunohistochemical changes associated with MMP-2 and type 1 collagen separately for the first time in the major salivary glands (the parotid, submaxillary, and sublingual glands) that occur with aging in mice.

Material and Methods

Fourteen Balb/c white mice (50-80 g) were used in this study. The animals were divided into two equal groups. Group I consisted of young animals (2-month-old) (n=7) and Group II consisted of older animals (18-month-old) (n=7). After routine histological follow-ups, Hematoxylin-eosin (H&E), Masson’s Trichrome staining and immunohistochemical staining was performed for type I collagen and MMP-2.

Results

We observed that there were age-related decreases in the number of acinar cells, increase in eosinophilic zymogen granules in cells, collagen accumulation in fibrotic areas and dilatation in interlobular ducts. Also, while type I collagen and MMP-2 immunoreactivity were moderate in the salivary glands of the young mice, they were high in the salivary glands of the old mice (p=0.001). In the H-score assessment, MMP-2 immunoreactivity was lower at a significant level in young mice than in old mice (p=0.001).

Conclusions

This study showed that anatomical, physiological and morphological abnormalities occur in all three major salivary glands as a natural consequence of aging.

Potential Role of Free Fatty Acids in the Pathogenesis of Periodontitis and Primary Sjögren's Syndrome

Clinical studies have shown that metabolic disorders such as type 2 diabetes and dyslipidemia are associated with increased risk of oral-related diseases, such as periodontitis and Sjögren’s syndrome. Although changes in the immune system are critical in both of these metabolic disorders and oral-related diseases, the mechanism underlying the interaction between these diseases remains largely unknown. Obesity and type 2 diabetes are known to be associated with higher concentrations of free fatty acids in blood. Among free fatty acids, saturated fatty acids such as palmitic acid have been demonstrated to induce inflammatory responses mainly via the innate immune systems, and to be involved in the pathogenesis of type 2 diabetes in tissues such as adipose tissue, liver, pancreas, and skeletal muscle. Here, we highlight recent advances in evidence for the potential involvement of palmitic acid in the pathogenesis of periodontitis and Sjögren’s syndrome, and discuss the possibility that improvement of the lipid profile could be a new strategy for the treatment of these diseases.

ALX/FPR2 receptor for RvD1 is expressed and functional in salivary glands

Sjögren's syndrome (SS) is an autoimmune disorder characterized by chronic inflammation and destruction of salivary and lacrimal glands, leading to dry mouth, dry eyes, and the presence of anti-nuclear antibodies. Despite modern advances, the current therapies for SS have no permanent benefit. A potential treatment could involve the use of resolvins, which are highly potent endogenous lipid mediators that are synthesized during the resolution of inflammation to restore tissue homeostasis. Our previous studies indicate that ALX/FPR2, the receptor for RvD1, is expressed and active in the rat parotid cell line Par-C10. Specifically, activation of ALX/FPR2 with RvD1 blocked inflammatory signals caused by TNF-α and enhanced salivary epithelial integrity. The goal of this study was to investigate RvD1 receptor expression and signaling pathways in primary salivary cells. Additionally, we determined the role of the aspirin-triggered 17R analog (AT-RvD1, a more chemically stable RvD1 epimeric form) in prevention of TNF-α-mediated salivary inflammation in mouse submandibular glands (mSMG). Our results indicate that ALX/FPR2 is expressed in mSMG and is able to elicit intracellular Ca2+ responses and phosphorylation of Erk1/2, as well as Akt. Given that these signaling pathways are linked to cell survival, we investigated whether AT-RvD1 was able to prevent programmed cell death in mSMG. Specifically, we determined that AT-RvD1 prevented TNF-α-mediated caspase-3 activation. Finally, we show that ALX/FPR2 is expressed in human minor salivary glands with and without SS, indicating the potential therapeutic use of AT-RvD1 for this condition.

Targeting TNF-α suppresses the production of MMP-9 in human salivary gland cells

OBJECTIVE

Tumour necrosis factor-α (TNF-α) is a pleiotropic cytokine that plays an essential role in inflammation and apoptosis. Our previous study suggested that TNF-α-induced activation of matrix metalloproteinase-9 (MMP-9) resulted in the destruction of acinar tissue in the salivary glands of patients with Sjögren's syndrome (SS) via disruption of the acinar cell-basement membrane. Recently, a wide array of biological agents has been designed to inhibit TNF, including etanercept and adalimumab. In this study, we demonstrate the suppressive effect of anti-TNF agents on TNF-α-induced MMP-9 production in NS-AV-AC, an immortalized human salivary gland acinar cell line.

MATERIALS AND METHODS

NS-AV-AC cells were treated with etanercept or adalimumab after TNF-α treatment. MMP-9 production and enzymatic activity were, respectively, visualized by real-time PCR and ELISA assay, and evaluated by gelatin zymography, and apoptosis was evaluated by DNA fragmentation assay.

RESULTS

TNF-α induced the production of MMP-9 in NS-SV-AC cells. However, this production was greatly inhibited by treatment with etanercept or adalimumab. In addition, TNF-α-induced DNA fragmentation was prevented by treatment with etanercept or adalimumab.

CONCLUSIONS

These results may indicate that anti-TNF agents would have therapeutic efficacy for preventing destruction of the acinar structure in the salivary glands of patients with SS.

TNF-α inhibits aquaporin 5 expression in human salivary gland acinar cells via suppression of histone H4 acetylation

Sjögren's syndrome is a systemic autoimmune disease characterized by reductions in salivary and lacrimal secretions. The mechanisms underlying these reductions remain unclear. We have previously shown that TNF-α plays an important role in the destruction of acinar structures. Here we examined TNF-α's function in the expression of aquaporin (AQP) 5 in human salivary gland acinar cells. Immortalized human salivary gland acinar (NS-SV-AC) cells were treated with TNF-α, and then the expression levels of AQP5 mRNA and protein were analysed. In addition, the mechanisms underlying the reduction of AQP5 expression by TNF-α treatment were investigated. TNF-α-treatment of NS-SV-AC cells significantly suppressed the expression levels of AQP5 mRNA and protein, and reduced the net fluid secretion rate. We examined the expression and activation levels of DNA methyltransferases (Dnmts) in NS-SV-AC cells treated with TNF-α. However, no significant changes were observed in the expression or activation levels of Dnmt1, Dnmt3a or Dnmt3b. Although we also investigated the role of NF-κB activity in the TNF-α-induced suppression of AQP5 expression in NS-SV-AC cells, we detected similar TNF-α suppression of AQP5 expression in non-transfected cells and in a super-repressor form of IκBα cDNA-transfected cell clones. However, interestingly, chromatin immunoprecipitation analysis demonstrated a remarkable decrease in levels of acetylated histone H4 associated with the AQP5 gene promoter after treatment with TNF-α in NS-SV-AC cells. Therefore, our results may indicate that TNF-α inhibition of AQP5 expression in human salivary gland acinar cells is due to the epigenetic mechanism by suppression of acetylation of histone H4.

T lymphocytes in Sjögren's syndrome: contributors to and regulators of pathophysiology

Sjögren's syndrome is a chronic autoimmune disorder characterized by lymphocytic infiltration and malfunction of the exocrine glands, resulting in dry mouth and eyes. This multigenic and multifunctional disease can present as primary Sjögren's syndrome or secondary to an underlying connective tissue disease. Immune activation subsequent to activation or apoptosis of glandular epithelial cells in genetically predisposed individuals may expose autoantigens, which engage self-perpetuating T cell dependent autoimmune sequelae. The cellular and molecular context of this immune response may drive proinflammatory (Th1 and Th17) and restrain inhibitory (Treg) pathways. Inability to suppress the immune response results in persistent tissue damage and compromised function of salivary and lacrimal glands. Defining the contributions of participating T cells may unravel strategies for therapeutic intervention.

Effectiveness of low-dose doxycycline (LDD) on clinical symptoms of Sjögren's syndrome: a randomized, double-blind, placebo controlled cross-over study

BACKGROUND

Matrix metalloproteinases (MMPs) are proteolytic enzymes that may contribute to tissue destruction in Sjögren's syndrome (SS). Low-dose doxycycline (LDD) inhibits MMPs. We evaluated the efficacy of LDD for the subjective symptoms in primary SS patients. This was a randomized, double blind, placebo controlled cross-over study. 22 patients were randomly assigned to receive either 20 mg LDD or matching placebo twice a day for 10 weeks. The first medication period was followed by 10-week washout period, after which the patient received either LDD or placebo, depending on the first drug received, followed by the second washout period. Stimulated saliva flow rates and pH were measured before and after one and ten weeks of each medication and after washout periods. VAS scale was used to assess the effect of LDD and placebo on following six subjective symptoms: xerostomia; xerophtalmia; difficulty of swallowing; myalgia; arthralgia; and fatigue. The effect was evaluated for each medication and washout period separately.

RESULTS

Overall, the effects of medications on subjective symptoms were minor. Wilcoxon test demonstrated increased fatigue with LDD during medication (p < 0.05). The differences may, however, reflect normal fluctuation of symptoms in SS patients.

CONCLUSION

LDD may not be useful in reducing the primary SS symptoms.

Increased serum levels of macrophage migration inhibitory factor in patients with primary Sjögren's syndrome

The objective of this study was to analyse levels of the proinflammatory cytokine macrophage migration inhibitory factor (MIF) in patients with primary Sjögren's syndrome (pSS) and to examine associations of MIF with clinical, serological and immunological variables. MIF was determined by ELISA in the sera of 76 patients with pSS. Further relevant cytokines (IL-1, IL-6, IL-10, IFN-γ and TNF-α) secreted by peripheral blood mononuclear cells (PBMC) were determined by ELISPOT assay. Lymphocytes and monocytes were examined flow-cytometrically for the expression of activation markers. Results were correlated with clinical and laboratory findings as well as with the HLA-DR genotype. Healthy age- and sex-matched volunteers served as controls. We found that MIF was increased in patients with pSS compared with healthy controls (p < 0.01). In particular, increased levels of MIF were associated with hypergammaglobulinemia. Further, we found a negative correlation of MIF levels with the number of IL-10-secreting PBMC in pSS patients (r = -0.389, p < 0.01). Our data indicate that MIF might participate in the pathogenesis of primary Sjögren's syndrome. MIF may contribute to B-cell hyperactivity indicated by hypergammaglobulinemia. The inverse relationship of IL-10 and MIF suggests that IL-10 works as an antagonist of MIF in pSS.

Primary Sjogren's syndrome: current and prospective therapies

OBJECTIVE

To summarize data on existing and experimental therapies for primary Sjogren's syndrome (pSS), referring both to sicca syndrome and to other systemic disease manifestations.

METHODS

Relevant English and non-English articles acquired through Medline were reviewed.

RESULTS

pSS usually has a benign clinical course, centered on sicca features and general musculoskeletal manifestations, and is managed symptomatically. However, a subset of patients develops more severe extraglandular disease that warrants close monitoring and aggressive treatment. For dry eyes and mouth, nonpharmacologic measures to preserve secretions, and tear and saliva substitutes, offer some symptomatic relief. Muscarinic agonists and topical cyclosporine yield well-documented improvement in ocular sicca features. Although traditional antirheumatic drugs are used empirically for polyarthritis and other Sjogren's symptoms, their efficacy in pSS overall and as disease-modifying agents is limited. For the potential severe, nonexocrine manifestations complicating pSS, standard high-dose immunosuppression is used. Among the biologic agents already examined in pSS, those targeting tumor necrosis factor (TNF)-alpha failed to demonstrate significant benefit. Nonetheless, rituximab and other B-cell-depleting therapies appear promising.

CONCLUSIONS

Treatment of pSS patients with severe extraglandular disease should differ from that of patients with predominantly sicca features and/or general muscoloskeletal manifestations. pSS treatment is mainly symptomatic, primarily directed against sicca complaints. The traditional anti-rheumatic agents show limited efficacy in the systemic process and use of systemic TNF-alpha inhibitors has been very disappointing. B cell depleting treatments and other newer biologic therapies appear more promising.

The future of biologic agents in the treatment of Sjögren's syndrome

The gain in knowledge regarding the cellular mechanisms of T and B lymphocyte activity in the pathogenesis of Sjögren's syndrome (SS) and the current availability of various biological agents (anti-TNF-alpha, IFN- alpha, anti-CD20, and anti-CD22) have resulted in new strategies for therapeutic intervention. In SS, various phase I and II studies have been performed to evaluate these new strategies. Currently, B cell-directed therapies seem to be more promising than T cell-related therapies. However, large, randomized, placebo-controlled clinical trials are needed to confirm the promising results of these early studies. When performing these trials, special attention has to be paid to prevent the occasional occurrence of the severe side effects.

Pathophysiology of Sjögren's syndrome

The term Sjögren's syndrome refers to keratoconjunctivitis sicca and xerostomia due to lymphocytic infiltrates of lachrymal and salivary glands. The current used criteria for diagnosis of primary Sjögren's syndrome is the American-European consensus. Primary Sjögren's syndrome is an autoimmune disorder characterized by lymphocytic infiltrates and destruction of the salivary and lachrymal glands and systemic production of autoantibodies to the ribonucleoprotein particles SS-A/Ro and SS-B/La. The infiltrating cells (T- and B-cells, dendritic cells) interfere with glandular function at several points: destruction of glandular elements by cell-mediated mechanisms; secretion of cytokines that activate pathways bearing the signature of type 1 and 2 interferons; production of autoantibodies that interfere with muscarinic receptors; and secretion of metalloproteinases (MMPs) that interfere with the interaction of the glandular cell with its extracellular matrix, which is necessary for efficient glandular function. As the process progresses, the mucosal surfaces become sites of chronic inflammation and the start of a vicious circle. Despite extensive study of the underlying cause of Sjögren's syndrome, the pathogenesis remains obscure. In broad terms, pathogenesis is multifactorial; environmental factors are thought to trigger inflammation in individuals with a genetic predisposition to the disorder.

Autoantibodies from Sjögren's syndrome induce activation of both the intrinsic and extrinsic apoptotic pathways in human salivary gland cell line A-253

Sjögren's syndrome (SS) is an autoimmune rheumatic disease that targets salivary and lachrymal glands, characterized by a high concentration of serum autoantibodies directed against nuclear and cytoplasmic antigens. It is known that autoantibodies can enter viable cells and this phenomenon has functional consequences including activation of apoptotic process. The objective of this work was to explore whether autoantibodies contained in IgG purified from Sjögren sera trigger apoptotic process in an experimental model represented by the human salivary gland cell line A-253. To define if the intrinsic or extrinsic pathways are activated, we examined which caspases are critical for inducing cell death. The results have demonstrated that morphological changes and DNA laddering, consistent with apoptotic cell death, occurred in A-253 cells treated with IgG from Sjögren sera. Sjögren IgG induced cleavage and activation of the effector caspase-3 and degradation of the caspase-3 substrate poly(ADP-ribose)polymerase. Both the intrinsic and extrinsic apoptotic pathways were activated, since both caspase-8 and caspase-9 cleavages occurred. In conclusion, autoantibodies contained in IgG purified from Sjögren sera mediate apoptosis of the A-253 cell line in a caspase-dependent manner.

Expression of aquaporin-5 in and fluid secretion from immortalized human salivary gland ductal cells by treatment with 5-aza-2'-deoxycytidine: a possibility for improvement of xerostomia in patients with Sjögren's syndrome

The aim of the present study was to investigate the possibility that ductal cells, which preferentially survive and/or proliferate in Sjögren's syndrome (SS) salivary glands of patients with SS, could acquire the functional expression of membrane water channel aquaporin-5 (AQP5). Thus, in this study, we demonstrate that an immortalized normal human salivary gland ductal cell (NS-SV-DC) line, lacking the expression of AQP5, acquires AQP5 gene expression in response to treatment with 5-aza-2'-deoxycytidine (5-Aza-CdR), a DNA demethylating agent. Confocal microscopic analysis revealed the localization of AQP5 expression mainly at the apical and lateral sides of the plasma membrane. The expressed AQP5 protein was functionally active because AQP5 expression resulted in a significant increase in the osmotically directed net fluid rate across monolayers of NS-SV-DC cells. By the analysis of bisulfite sequencing of CpG islands in the AQP5 promoter, hypermethylation within the consensus Sp1-binding sites was commonly observed in parental cell clones, whereas demethylation at the CGs, one in the second consensus Sp1 element and the other outside of the third consensus Sp1 element in the AQP5 promoter, was detected in NS-SV-DC cells after treatment with 5-Aza-CdR. By analyzing the luciferase activity of transfected AQP5 promoter vectors, it became evident that demethylation at the CGs cooperatively functions between these two sites to induce AQP5 expression. Our data, therefore, suggest that treatment of ductal cells with 5-Aza-CdR could result in the expression of the AQP5 gene, thereby leading to increased fluid secretion from ductal cells in SS salivary glands.

Segment-specific but pathologic laminin isoform profiles in human labial salivary glands of patients with Sjogren's syndrome

OBJECTIVE

To assess the laminins in basement membrane of the labial salivary glands of patients with Sjogren's syndrome (SS) and healthy controls.

METHODS

Labeling of laminin alpha1-alpha5, beta1, beta2, gamma1, and gamma2 chains was performed using immunohistochemistry with chain-specific monoclonal antibodies and pattern recognition analysis of the labeled specimens.

RESULTS

Laminin alpha1, alpha2, and alpha4 chains were detected exclusively in the acinar basement membranes, whereas laminin alpha3, alpha5, beta1, gamma1, and gamma2 chains were also detected in ductal basement membranes. Laminin beta2 chain was not found. In patients with SS, laminin alpha1 and alpha2 chains were weakly labeled, but laminin alpha4 labeling was also intense in areas not infiltrated by lymphocytes. Pattern recognition analysis suggested that laminin alpha1, alpha2, and alpha4 chains were associated with acinar cells, myoepithelial cells, and tissue damage/repair, respectively.

CONCLUSION

All salivary gland basement membranes signal through laminin 5, laminin 6, and laminin 10 trimers, but acinar basement membranes also signal through laminin 1, laminin 2, and laminin 8 trimers. Laminin alpha1 chain/laminin 1 may play a central role in the maintenance of acinar cells in healthy glands. This possibility was supported by the finding of variable expression of laminin alpha1 chain/laminin 1 in acinar basement membrane and its weak expression in SS with acinar cell atrophy. The impairment of myoepithelial laminin alpha2 chain/laminin 2 in patients with SS indicates a double defect in the acinar compartment and pathologic extracellular matrix-to-cell signaling, which may contribute to structural deterioration and functional abnormality of the exocrine glands.

Etanercept in Sjögren's syndrome: a twelve-week randomized, double-blind, placebo-controlled pilot clinical trial

OBJECTIVE

To assess the safety and potential efficacy of etanercept in the treatment of Sjögren's syndrome (SS).

METHODS

This pilot study was a 12-week randomized, double-blind, placebo-controlled trial of etanercept, with 14 subjects in each group. Patients received 25 mg of etanercept or placebo (vehicle) by twice-weekly subcutaneous injection. Patients met the American-European Consensus Group criteria for SS. The primary outcome required at least 20% improvement from baseline values for at least 2 of the following 3 domains: subjective or objective measures of dry mouth, subjective or objective measures of dry eyes, and IgG level or erythrocyte sedimentation rate (ESR).

RESULTS

Of the 14 patients taking etanercept, 11 had primary SS and 3 had SS secondary to rheumatoid arthritis. Baseline measures did not differ between the 2 groups. Three etanercept-treated patients and 1 placebo-treated patient did not complete the trial. Five etanercept-treated patients and 3 placebo-treated patients showed improvement from baseline in the primary outcome variable at 12 weeks, but the difference was not statistically significant. There were no significant differences between the groups for changes in subjective measures of oral or ocular symptoms (by visual analog scale), the IgG level, Schirmer I test result, van Bijsterveld score, or salivary flow. At 12 weeks, the ESR had decreased in the etanercept group compared with baseline (P = 0.004); however, the mean reduction was only 18.6%.

CONCLUSION

We found no evidence to suggest that treatment with etanercept at a dosage of 25 mg twice weekly for 12 weeks was clinically efficacious in SS. A larger trial will be necessary to definitively address the efficacy of etanercept in the treatment of SS.

Increase in the ratio of matrix metalloproteinase-9 to tissue inhibitor of metalloproteinase-1 in saliva from patients with primary Sjögren's syndrome

BACKGROUND

To investigate the ratio of matrix metalloproteinase (MMP) to tissue inhibitor of metalloproteinase (TIMP) in primary Sjögren's syndrome (PSS), patients and healthy subjects MMP-2, 9 and TIMP-1, 2 levels were measured in saliva.

METHODS

Stimulated whole-mixed saliva was collected from 32 patients and 26 healthy subjects. MMP-2, 9 and TIMP-1, 2 levels were measured using enzyme-linked immunosorbent assay (ELISA) and the sandwich enzyme immunoassay (sandwich EIA). Zymography and reverse zymography were used to identify MMPs and TIMPs.

RESULTS

MMP-9 (gelatinase-B) level in saliva was significantly increased in the patients. MMP-9 (ng/ml): patients 231.02 +/- 151.77 (mean +/- S.D.), healthy subjects 145.87 +/- 111.65 (p < 0.05). MMP-2 levels were not detected with this system kit in either healthy subjects or patients. The differences in TIMPs were only trends and not statistically significant (p > 0.05). Accordingly, MMP-9/TIMP-1 was greatly increased in the patients (2.60 +/- 1.18) than in the healthy subjects (1.28 +/- 1.11) (p < 0.01).

CONCLUSION

This study found that MMP-9/TIMP-1 and MMP-9 levels in the saliva were significantly higher in pSS patients than those in healthy subjects. Our results indicate that the increase in MMP-9/TIMP-1, rather than the increase in MMP-9, in pSS patients' saliva is strongly involved in destruction of glandular and salivary duct tissues.

Inefficacy of infliximab in primary Sjögren's syndrome: results of the randomized, controlled Trial of Remicade in Primary Sjögren's Syndrome (TRIPSS)

OBJECTIVE

There is no effective treatment for patients with primary Sjögren's syndrome (SS). Since tumor necrosis factor alpha (TNF alpha) could be a key element in the pathogenesis of primary SS, we conducted a multicenter, randomized, double-blind, placebo-controlled trial to evaluate the effect of infliximab in primary SS.

METHODS

A total of 103 patients with primary SS were randomly assigned to receive infliximab infusions (5 mg/kg) or placebo at weeks 0, 2, and 6 and were followed up for 22 weeks. All patients fulfilled the new American-European Consensus Group criteria for SS and had active disease as assessed by values >50 mm on 2 of 3 visual analog scales (VAS) (0-100 mm) that evaluated joint pain, fatigue, and buccal, ocular, skin, vaginal, or bronchial dryness. A favorable overall response was defined as the patient having > or =30% improvement between weeks 0 and 10 in the values on 2 of the 3 VAS. Secondary end points were values on each VAS separately, the number of tender and swollen joints, the basal salivary flow rate, results of the Schirmer test for lacrimal gland function, the focus score on labial salivary gland biopsy, the level of C-reactive protein, and the erythrocyte sedimentation rate evaluated at weeks 0, 10, and 22, as well as quality of life evaluated by use of the generic Short Form 36 questionnaire administered at weeks 0, 10, and 22.

RESULTS

At week 10, 26.5% of patients receiving placebo and 27.8% of patients treated with infliximab had a favorable overall response (P = 0.89), and at week 22, 20.4% of the placebo group and 16.7% of the infliximab group had a favorable response (P = 0.62). In addition, the 2 groups did not differ in any of the secondary end points over the 22 weeks of the trial. Severe adverse events reported in the infliximab group did not differ from those observed in previous studies.

CONCLUSION

This randomized, double-blind, placebo-controlled study of an anti-TNF agent did not show any evidence of efficacy of infliximab in primary SS.

Expression of matrix metalloproteinases MMP-2, MMP-9 and their tissue inhibitors TIMP-1, -2, and -3 in benign and malignant tumours of the salivary gland

AIMS

The balance between matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) is involved in the morphogenesis of the normal salivary gland as well as in mechanisms of tumour invasion and metastasis. Our aim was to analyse protein and mRNA expression of MMPs and TIMPs in normal salivary gland tissue and in various salivary gland neoplasms.

METHODS AND RESULTS

Immunohistochemistry for MMP-2, MMP-9, TIMP-1, -2 and -3 was performed in 20 malignant and six benign salivary gland tumours. The immunoscores of MMP-2 were significantly higher in carcinomas compared with adenomas (P = 0.0028). The MMP/TIMP ratio was significantly higher in carcinomas than in adenomas (P = 0.0097). In mucoepidermoid carcinomas MMP-2 expression was preferentially observed in the intermediate cell type. Neoplastic acinar cells of acinic cell carcinoma demonstrated de novo expression of MMP-2, MMP-9, TIMP-1, and TIMP-2. Immunoscores of TIMP-3 were not decreased in malignant tumours compared with adenomas. In accordance with the immunostaining of MMP-2 and -9, gelatinolytic activity could be demonstrated by in-situ zymography. The mRNA expression of MMPs and TIMPs analysed by real-time reverse transcriptase-polymerase chain reaction in three malignant and two benign tumours and their corresponding normal tissue did not generally correlate with their protein expression.

CONCLUSIONS

Our findings suggest a disturbed balance between MMP and TIMP in malignant salivary gland tumours. MMP-2 expression in particular seems to be related to the invasive properties and the malignant potential of these tumours.

New approaches to the treatment of Sjögren's syndrome: soon beyond symptomatic relief?

Sjögren's syndrome (SS) is a common autoimmune disease characterized by destruction and dysfunction of the salivary and lachrymal glands. Systemic manifestations occur in almost one third of patients with SS. Treatment of SS has been long considered as disappointing, being mainly restricted to local management with artificial tears and oral lubricants or to the use of immunosuppression-based therapies for systemic disease. Better knowledge of the pathogenesis of SS, including the role of retroviruses and cytokines and the discovery of aquaporins, provides new perspectives for the local and systemic management of this disease. Our goal is to focus on these recent therapeutic progresses.

Effect of ubiquitin-proteasome pathway on mouse blastocyst implantation and expression of matrix metalloproteinases-2 and -9

Previous studies have documented that ubiquitin-related proteins are present in human, baboon, rhesus monkey, cow, sheep, and mouse pregnant uteri, indicating that the ubiquitin-proteasome pathway (UPP) may be involved in the extensive uterine remodeling during mammalian early pregnancy, but there is still no direct evidence. A mouse intrauterine injection model was employed to study the direct effect of the UPP on mouse embryo implantation and its possible mechanisms. On Day 3 of pregnancy in each mouse, one of the uterine horns in each mouse was injected with different concentrations of lactacystin, a specific proteasome inhibitor, or anti-ubiquitin antibody, and the other side was used as a control. On days 5, 6, and 7, the number of implanted embryos was counted and the expression and gelatinolytic activities of matrix metalloproteinase-2 (MMP-2) and MMP-9 were studied. Results presented here illustrate that injection of lactacystin and anti-ubiquitin antibody significantly inhibited mouse embryo implantation. Further investigations by reverse transcription-polymerase chain reaction and gelatin zymography showed that MMP-2 and MMP-9 mRNA expression, as well as the gelatinolytic activity of MMP-9 in the lactacystin-treated uterine horn, significantly decreased, whereas the activity of MMP-2 was not significantly affected. The results obtained from this study, together with previous reports, suggest that the UPP is involved in mouse embryo implantation, and UPP's effect on embryo implantation is achieved at least in part by regulating MMP-2 and MMP-9 mRNA expression and the gelatinolytic activity of MMP-9.

Cisplatin induces apoptosis in oral squamous carcinoma cells by the mitochondria-mediated but not the NF-kappaB-suppressed pathway

Cisplatin (CDDP) is a potent DNA-damaging anticancer agent, and its cytotoxic action is exerted by the induction of apoptosis. However, activation of the transcription factor NF-kappaB results in protection against apoptosis. We examined the molecular mechanisms involved in the induction of apoptosis by CDDP as regards both suppression of NF-kappaB and activation of caspases. Human oral squamous carcinoma cells (B88) were employed in this study. We found that CDDP treatment affected neither NF-kappaB activity nor the expression levels of antiapoptotic proteins, including TRAF-1, TRAF-2, and cFLIP, in B88 cells. However, two apoptosome molecules, cytochrome c and Apaf-1, were significantly augmented in the cytoplasm by CDDP treatment. Further, the activation of caspase-9 and caspase-3, downstream molecules leading to mitochondria-mediated apoptosis, were detected after treatment with CDDP. Finally, apoptosis was also clearly observed, as evidenced by cleavage of PARP through the activation of caspase-3. These findings suggest that CDDP exerts its apoptotic action by the mitochondria-mediated activation of caspases but not by the activation of caspases due to the inhibition of NF-kappaB activity that follows the suppression of antiapoptotic proteins.

The role of transcription factors in allergic inflammation

The induction of allergic inflammation and the expression of allergic disorders are dependent on the coordinated regulation of numerous genes. The products of these genes determine lymphocyte phenotype, immunologic responsiveness, eosinophil and mast cell development, activation, migration and life span, adhesion molecule expression, cytokine synthesis, cell-surface receptor display, and processes governing fibrosis and tissue repair. Although the expression of gene products involved in these processes is regulated at multiple levels (eg, transcription, mRNA processing, translation, phosphorylation, and degradation), transcription represents an essential and often the most important determinant of their contribution to cellular function. Signal-dependent and cell type-specific regulation of gene expression is generally achieved by means of combinatorial interactions between sequence-specific transcription factors that recruit chromatin remodeling machinery and general transcription factors to promoter and enhancer regions of RNA polymerase II-dependent genes. As targets of signal-transduction pathways, transcription factors integrate the response of the cell to the myriad of inputs it receives. This integration can be accomplished by the effect of signaling cascades on the activation status or subcellular locus of transcription factors or by transcription factor dimerization induced by means of ligand binding. This review will identify the major families of transcription factors important in allergic mechanisms and discuss their interactions, their mechanisms of action, and their interrelated and competitive actions, as well as implications for therapy of allergic disorders.

NF-kappa B: arresting a major culprit in cancer

Nuclear factor-kappa B (NF-kappa B) has long been known to play a central role in the immune system by regulating the expression of key genes. Moreover, activation of this transcription factor helps a wide variety of cell types survive damage induced by pro-apoptotic stimuli. Because of its crucial role in the regulation of pro-inflammatory genes, NF-kappa B is a promising target for the discovery of anti-inflammatory drugs. More recently, NF-kappa B has also emerged as a major culprit in a variety of human cancers mainly because of its ability to protect transformed cells from apoptosis. The pharmaceutical industry should, therefore, seriously consider testing inhibitors of NF-kappa B, identified as part of their anti-inflammatory drug discovery programs, in combination with other chemotherapeutic drugs in models of cancer.

Current and potential treatments for primary Sjögren's syndrome

A precise definition of primary Sjögren's syndrome resting on 'revised' or 'international' criteria has been accepted by most experts. This is important because the symptoms of primary Sjögren's syndrome, namely, dryness, fatigue, and pain, are common in the population at large and can occur in the absence of autoimmune disease as a result of medication use, anxiety and depression, or normal aging. This widely accepted definition is particularly valuable as a tool for obtaining homogenous patient populations for trials of new therapeutic agents. In this review article, before discussing treatments for complications and current hopes about second-line drugs, we present an update on available treatments forthe symptomatic triad (dryness, fatigue, and diffuse pain) seen in autoimmune Sjögren's syndrome and in some cases of isolated sicca syndrome. These very bothersome and permanent symptoms have a negative effect on quality of life. The most recent data show that systemic cholinergic agonists (pilocarpine and cevimiline) are effective in the symptomatic treatment of dryness, that cyclosporine eye drops may relieve ocular symptoms, and that TNFalpha inhibitors may find a new indication in Sjögren's syndrome.

Suppression of tumor necrosis factor alpha-induced matrix metalloproteinase 9 production in human salivary gland acinar cells by cepharanthine occurs via down-regulation of nuclear factor kappaB: a possible therapeutic agent for preventing the destruction of the acinar structure in the salivary glands of Sjögren's syndrome patients

OBJECTIVE

Our previous results suggested that suppression of tumor necrosis factor alpha (TNFalpha)-induced matrix metalloproteinase 9 (MMP-9) could prevent the destruction of acinar tissue in the salivary glands of patients with Sjögren's syndrome (SS). The present study was undertaken to investigate the effect of cepharanthine on the suppression of TNFalpha-induced MMP-9 production in NS-SV-AC, an SV40-immortalized normal human acinar cell clone.

METHODS

After pretreatment with or without cepharanthine, NS-SV-AC cells were treated with TNFalpha alone or with a combination of TNFalpha and cepharanthine. The expression of MMP-9 was then examined at the protein and messenger RNA levels. In addition, the effect of cepharanthine on the morphogenetic behavior of NS-SV-AC cells cultured on type IV collagen-coated dishes in the presence of TNFalpha was examined.

RESULTS

Although TNFalpha induced the production of MMP-9 in NS-SV-AC cells, this production was greatly suppressed when cells were pretreated with cepharanthine, followed by treatment with both TNFalpha and cepharanthine. In addition, cepharanthine suppressed the TNFalpha-stimulated NF-kappaB activity by partly preventing the degradation of IkappaBalpha protein in NS-SV-AC cells. When NS-SV-AC cells were seeded on type IV collagen-coated dishes in the presence of both TNFalpha and plasmin, type IV collagen interaction with the cells was lost and the cells entered apoptosis. However, pretreatment with cepharanthine restored the aberrant in vitro morphogenesis of the NS-SV-AC cells.

CONCLUSION

These results may indicate a molecular mechanism by which cepharanthine is able to protect against the destruction of the acinar structure in salivary glands from patients with SS.

Role of nuclear factor kappaB in synovial inflammation

The evaluation of molecular pathways has revealed novel insights into the pathophysiology of rheumatoid arthritis in the last several years. Gene transcription factors such as nuclear factor kB (NFkB) are activated by extracellular signals or cell-to-cell interactions that are converted into intracellular activation signals through receptor molecules located in the cell membrane. The number of known genes being translated after NFkB activation is increasing steadily. These genes includes cytokines, chemokines, growth factors, cellular ligands, and adhesion molecules. Because many of these genes are part of the pathogenesis of RA, there is considerable interest in the evaluation of the synovium-specific effects of NFkB to unveil its potential for future therapeutic strategies. The goal is to evolve these strategies from the therapies that have a wide spectrum of effects and side effects into rheumatoid arthritis-specific therapies designed to inhibit distinct molecular pathways within the synovium.

Stable inhibition of NF-kappa B in salivary gland cells does not enhance sensitivity to TNF-alpha-induced apoptosis due to upregulation of TRAF-1 expression

The transcription factor NF-kappa B inhibits the apoptotic response induced by TNF-alpha. However, in salivary gland cell clones (ACMT-6 and ACMT-7) in which NF-kappa B activation was suppressed by introduction of a super-repressor form of I kappa B-alpha cDNA, TNF-alpha did not cause apoptosis. Thus, to investigate the molecular mechanism involved in the unresponsiveness of these cell clones to TNF-alpha-induced apoptosis, we examined the effect of TNF-alpha on the expression of antiapoptotic proteins, including TNF receptor-associated factor (TRAF)-1, TRAF-2, cellular inhibitor of apoptosis protein (cIAP)-1, and cIAP-2. Here we show that expression of TRAF-1 was commonly detected by treatment with TNF-alpha in ACMT-6, ACMT-7, and an empty vector-transfected cell clone (ACpRc-1) and that downregulation of TRAF-1 protein by either treatment with an antisense oligonucleotide or introduction of an antisense plasmid resulted in the induction of apoptosis in these cell clones. Our results, therefore, suggest that one of the mechanisms by which cells acquire resistance to TNF-alpha-induced apoptosis is a TNF-alpha induction of TRAF-1.

Infliximab in patients with primary Sjögren's syndrome: a pilot study

OBJECTIVE

Tumor necrosis factor alpha (TNFalpha) is a proinflammatory cytokine involved in the pathogenesis of Sjögren's syndrome (SS), and blockade of TNFalpha may reduce the activity of the disease. The purpose of this study was to evaluate the safety and potential efficacy of infliximab, a chimeric human-mouse anti-TNFalpha monoclonal antibody, in patients with active primary SS.

METHODS

This was a single-center, open-label pilot study. Sixteen patients with active primary SS received 3 infusions of infliximab (3 mg/kg) at 0, 2, and 6 weeks. Standard clinical assessment, complete ophthalmologic testing, and functional evaluation of salivary flow were performed at baseline and at weeks 2, 6, 10, and 14.

RESULTS

All patients completed the study. There was statistically significant improvement in all clinical and functional parameters, including global assessments (patient's global assessment, patient's assessment of pain and fatigue, physician's global assessment), erythrocyte sedimentation rate, salivary flow rate, the Schirmer I test, tender joint count, fatigue score, and dry eyes and dry mouth. This clinical benefit was observed at week 2 and was maintained throughout the study and the 2-month followup period. The treatment was well tolerated in all patients, and no significant adverse events were seen. No lupus-like syndrome was observed, and no anti-double-stranded DNA antibodies were observed that were attributable to infliximab therapy.

CONCLUSION

In patients with active primary SS, a loading-dose regimen of 3 infusions of infliximab provided a fast and significant clinical benefit without major adverse reactions. It was possible to maintain statistically significant improvement for up to 8 weeks after the third infusion.