TNF-α-induced Inhibition of Protein Myristoylation Via Binding Between NMT1 and Sorbs2 in Osteoblasts.

BACKGROUND/AIM: Bone resolution due to tumor invasion often occurs on the surface of the jaw and is important for clinical prognosis. Although cytokines, such as TNF-α are known to impair osteoblasts, the underlying mechanism remains unclear. Protein myristoylation, a post-translational modification, plays an important role in the development of immune responses and cancerization of cells. A clear understanding of the mechanisms underlying this involvement will provide insights into molecular-targeted therapies. N-myristoyltransferase1 (NMT1), a specific enzyme involved in myristoylation, is expressed in cancer cells and in other normal cells, suggesting that changes in myristoylation may result from the regulation of NMT1 in cancer cells. MATERIALS AND METHODS: Using newly emerging state-of-the-art techniques such as the Click-it assay, RNA interference, mass spectrometry, immunoprecipitation, immunocytochemistry, and western blotting, the expression of myristoylated proteins and the role of TNF-α stimulation on NMT1 and Sorbs2 binding were evaluated in a murine osteoblastic cell line (MC3T3-E1). RESULTS: The expression of myristoylated proteins was detected; however, TNF-α stimulation resulted in their inhibition in MC3T3-E1 cells. The expression of NMT1 also increased. Immunoprecipitation and mass spectrometry identified Sorbs2 as a novel binding protein of NMT1, which upon TNF-α stimulation, inhibited myristoylation. CONCLUSION: The binding between NMT1 and Sorbs2 can regulate myristoylation, and NMT1 can be considered as a potential target molecule for tumor invasion.

Regulation of NF-kB Signalling Through the PR55ß-RelA Interaction in Osteoblasts.

BACKGROUND/AIM: Nuclear factor kappa B (NF-kB) signalling including the RelA subunit is activated upon fibroblast growth factor (FGF) stimulation. A clear understanding of the mechanisms underlying this action will provide insights into molecular targeting therapy. Furthermore, protein phosphatase 2A (PP2A) is involved in RelA dephosphorylation, but little is known about the underlying mechanism. MATERIALS AND METHODS: Because the regulatory subunits of PP2A drive NF-kB signalling via RelA, we used qRT-PCR and immunoblot analysis to investigate the expression of these subunits in MC3T3-E1 cells. We examined weather FGF2 interacts with NF-kB using immunocytochemistry (IC), immunoprecipitation (IP), and pull-down assay (PD) using recombinant proteins. RESULTS: PR55ß expression was increased, whereas activated RelA was dephosphorylated upon FGF2 stimulation. Further, the interaction of PR55ß with RelA was confirmed by IC, IP, and PD. CONCLUSION: FGF2-induced PR55ß directly interacts with RelA and regulates NF-kB signalling.

The diagnostic utility of submandibular gland sonography and labial salivary gland biopsy in IgG4-related dacryoadenitis and sialadenitis: Its potential application to the diagnostic criteria.

Objectives: In this study, we investigated the diagnostic utility of submandibular gland (SMG) sonography and labial salivary gland (LSG) biopsy as a less invasive procedure for diagnosing IgG4-related dacryoadenitis and sialadenitis (IgG4-DS)Methods: Sixty-eight patients with suspected IgG4-DS by presenting swelling of elevated serum IgG (>1747 mg/dl) and/or swelling glands underwent SMG sonography, LSG biopsy and measurement for serum IgG4. SMG sonographic diagnosis was determined by the following characteristic changes; 'hypoechoic areas of a nodal pattern with high vascularity' and/or 'hypoechoic areas of a reticular pattern in the superficial part'.Results: Thirty-one patients were diagnosed with IgG4-DS, 5 with IgG4-RD unaccompanied by lacrimal and salivary gland lesions, 28 with Sjögren's syndrome, and 4 with malignant lymphoma. The sensitivity, specificity, and accuracy of SMG sonography and LSG biopsy were 100%, 83.8%, 91.2% and 64.5%, 73.8%, 75.0%, respectively. Moreover, those of SMG sonography and LSG biopsy combined with serum IgG4 concentration (>135 mg/dl) were 100%, 94.6%, 97.1% and 64.5%, 91.9%, 79.4%, respectively.Conclusion: LSG biopsy needs to be extremely careful to diagnose IgG4-DS because of its low sensitivity. SMG sonography is sufficient for the diagnosis of IgG4-DS, especially when combined with serologic analysis. Thus, SMG sonography could adapt to the diagnostic criteria of IgG4-DS as a non-invasive method.

Impaired Junctions and Invaded Macrophages in Oral Epithelia With Oral Pain.

Recurrent or chronic oral pain is a great burden for patients. Recently, the links between epithelial barrier loss and disease were extended to include initiation and propagation. To explore the effects of pathohistological changes in oral epithelia on pain, we utilized labial mucosa samples in diagnostic labial gland biopsies from patients with suspected Sjögren's syndrome (SS), because they frequently experience pain and discomfort. In most labial mucosa samples from patients diagnosed with SS, disseminated epithelial cellular edema was prevalent as ballooning degeneration. The disrupted epithelia contained larger numbers of infiltrating macrophages in patients with oral pain than in patients without pain. Immunohistochemistry revealed that edematous areas were distinct from normal areas, with disarranged cell-cell adhesion molecules (filamentous actin, E-cadherin, ß-catenin). Furthermore, edematous areas were devoid of immunostaining for transient receptor potential channel vanilloid 4 (TRPV4), a key molecule in adherens junctions. In an investigation on whether impaired TRPV4 affect cell-cell adhesion, calcium stimulation induced intimate cell-cell contacts among oral epithelial cells from wild-type mice, while intercellular spaces were apparent in cells from TRPV4-knockout mice. The present findings highlight the relationship between macrophages and epithelia in oral pain processing, and identify TRPV4-mediated cell-cell contacts as a possible target for pain treatment.

Regulation of ß-Catenin Phosphorylation by PR55ß in Adenoid Cystic Carcinoma.

BACKGROUND/AIM: Adenoid cystic carcinoma (AdCC) is a rare cancer of the salivary gland with high risk of recurrence and metastasis. Wnt signalling is critical for determining tumor grade in AdCC, as it regulates invasion and migration. ß-catenin dephosphorylation plays an important role in the Wnt pathway, but its underlying molecular mechanism remains unclear. MATERIALS AND METHODS: Because the regulatory subunits of protein phosphatase 2A (PP2A) drive Wnt signalling via target molecules, including ß-catenin, we used qRT-PCR and immunoblot analysis to investigate the expression of these subunits in an AdCC cell line (ACCS) and a more aggressive subline (ACCS-M). RESULTS: PR55ß was highly expressed in ACCS-M, suggesting its functional importance. In addition, PR55ß expression was associated with tumor grade, with ACCS-M exhibiting higher PR55ß levels. More importantly, knockdown of PR55ß in ACCS-M cells significantly reduced invasiveness and metastatic ability. Furthermore, dephosphorylation and total levels of ß-catenin were dependent on PR55ß in ACCS-M. Finally, we confirmed a correlation between PR55ß staining intensity and histopathological type in human AdCC tissues. CONCLUSION: Our study provides new insight into the interaction between PR55ß and ß-catenin and suggests that PR55ß may be a target for the clinical treatment of AdCC.

Involvement of the T-box transcription factor Brachyury in early-stage embryonic mouse salivary gland.

The mouse submandibular gland (SMG) is important organ for embryonic development, and branching morphogenesis is regulated by many molecules containing transcription factors. Real-time reverse transcriptase polymerase chain reaction revealed that the expression of Brachyury increased in the SMG and peaked between E12.5-E13.5, concomitant with the early stage of branching morphogenesis. The expression of Brachyury in SMG rudiments between E12.5-E13.5 was confirmed by western blotting. In addition, fibronectin and Btbd7 (regulated by fibronectin), which are both essential for cleft formation, were expressed strongly during the same period. The Sox2 and Wnt3a, which regulate cell growth, were also expressed strongly during E12.5-E13.5. On the other hand, cleft formation and branching morphogenesis was suppressed by knockdown of Brachyury gene, suggesting that Brachyury plays a central role in regulating cell growth and cleft formation in early-stage embryonic mouse salivary gland development.

Efficient regulation of branching morphogenesis via fibroblast growth factor receptor 2c in early-stage embryonic mouse salivary glands.

Salivary gland (SG) defects have a wide range of health implications, including xerostomia, bacterial infections, and oral health issues. Branching morphogenesis is critical for SG development. A clear understanding of the mechanisms underlying this process will accelerate SG regeneration studies. Fibroblast growth factor receptor 2 (FGFR2) interacts with multiple fibroblast growth factors (FGFs), which promote development. FGFR2 consists of two isoforms, FGFR2b and FGFR2c. FGFR2b is critical for SG development, but little is known about the expression and function of FGFR2c. We investigated the expression of all FGFR family members in fetal SGs between embryonic day 12.5 (E12.5) and E18.5. Based on RT-PCR, we observed an increase in the expression of not only Fgfr2b, but also Fgfr2c in early-stage embryonic mouse SGs, suggesting that FGFR2c is related to SG development. The branch number decreased in response to exogenous FGF2 stimulation, and this effect was suppressed by a mouse anti-FGFR2c neutralizing antibody (NA) and siRNA targeting FGFR2c, whereas FGFR2b signaling was not inhibited. Moreover, the expression of marker genes related to EMT was induced by FGF2, and this expression was suppressed by the NA. These results suggested that branching morphogenesis in SGs is regulated by FGFR2c, in addition to FGFR2b. Interestingly, FGFR2c signaling also led to increased fgf10 expression, and this increase was suppressed by the NA. FGFR2c signaling regulates branching morphogenesis through the activation of FGFR2b signaling via increased FGF10 autocrine. These results provide new insight into the mechanisms by which crosstalk between FGFR2b and FGFR2c results in efficient branching morphogenesis.

The diagnostic utility of labial salivary gland biopsy in IgG4-related disease.

OBJECTIVE: For the definitive diagnosis of IgG4-related disease (IgG4-RD), biopsies of local lesions are recommended so as to exclude other diseases, including lymphoma and cancer. However, performing biopsies of underlying organs is technically difficult. In this study, we examined the diagnostic utility of labial salivary gland (LSG) biopsy as a less invasive procedure. METHODS: Sixty-six patients with suspected IgG4-RD by clinical findings or high serum IgG4 underwent LSG biopsy. We examined the relationship between the number of IgG4-positive plasma cells in LSG and clinical findings. RESULTS: The final diagnosis was 45 patients with IgG4-RD, 12 with Sjögren's syndrome, four with suspected Sjögren's syndrome, three with malignant lymphoma, one with systemic lupus erythematosus, and one with Warthin's tumor. The sensitivity, specificity, and accuracy of LSG biopsy were 55.6%, 100.0%, and 70.0%, respectively. Forty-five IgG4-RD patients were divided into two groups: 1) 25 with lesions of salivary glands (IgG4-RD S+) and 2) 20 without these lesions (IgG4-RD S-). Seventeen of 25 (68.0%) IgG4-RD S + and 8 of 20 (40.0%) IgG4-RD S - patients were positive for LSG biopsy. In the IgG4-RD S - patients, the mean number of affected organs and serum IgG4 in the positive cases for LSG biopsy were significantly higher than in the negative cases. CONCLUSION: A solo LSG biopsy is insufficient for the diagnosis of IgG4-RD because of its low sensitivity. However, LSG biopsy combined with clinical findings, including serum IgG4 and number of affected organs, may contribute towards a diagnosis of IgG4-RD patients with affected underlying organs.

Effectiveness of imaging modalities for screening IgG4-related dacryoadenitis and sialadenitis (Mikulicz's disease) and for differentiating it from Sjögren's syndrome (SS), with an emphasis on sonography.

INTRODUCTION: The aim of this study was to clarify the effectiveness of various imaging modalities and characteristic imaging features in the screening of IgG4-related dacryoadenitis and sialadenitis (IgG4-DS), and to show the differences in the imaging features between IgG4-DS and Sjögren's syndrome (SS). METHODS: Thirty-nine patients with IgG4-DS, 51 with SS and 36 with normal salivary glands were enrolled. Images of the parotid and submandibular glands obtained using sonography, 2-[(18)F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT), computed tomography (CT) and magnetic resonance imaging (MRI) were retrospectively analyzed. Six oral and maxillofacial radiologists randomly reviewed the arranged image sets under blinded conditions. Each observer scored the confidence rating regarding the presence of the characteristic imaging findings using a 5-grade rating system. After scoring various findings, diagnosis was made as normal, IgG4-DS or SS, considering all findings for each case. RESULTS: On sonography, multiple hypoechoic areas and hyperechoic lines and/or spots in the parotid glands and obscuration of submandibular gland configuration were detected mainly in patients with SS (median scores 4, 4 and 3, respectively). Reticular and nodal patterns were observed primarily in patients with IgG4-DS (median score 5). FDG-PET/CT revealed a tendency for abnormal (18)F-FDG accumulation and swelling of both the parotid and submandibular glands in patients with IgG4-DS, particularly in the submandibular glands. On MRI, SS had a high score regarding the findings of a salt-and-pepper appearance and/or multiple cystic areas in the parotid glands (median score 4.5). Sonography showed the highest values among the four imaging modalities for sensitivity, specificity and accuracy. There were significant differences between sonography and CT (p = 0.0001) and between sonography and FDG-PET/CT (p = 0.0058) concerning accuracy. CONCLUSIONS: Changes in the submandibular glands affected by IgG4-DS could be easily detected using sonography (characteristic bilateral nodal/reticular change) and FDG-PET/CT (abnormal (18)F-FDG accumulation). Even inexperienced observers could detect these findings. In addition, sonography could also differentiate SS. Consequently, we recommend sonography as a modality for the screening of IgG4-DS, because it is easy to use, involves no radiation exposure and is an effective imaging modality.

Cytokine profiles contribute to understanding the pathogenic difference between Good syndrome and oral lichen planus: two case reports and literature review.

We described and analyzed the pathogenic difference between Good syndrome (GS) and oral lichen planus (OLP) in oral mucosa. Good syndrome (GS) is a rare disease characterized by B and T cell immunodeficiency associated with hypogammaglobulinemia and thymoma. GS patients frequently develop oral lichenoid lesions with lymphocytic infiltration beneath the basal layer. Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa characterized by destruction of basal cells by Langerhans cells, macrophages, and T lymphocytes. Although the histological features of the lesions of both diseases are very similar, the pathogenesis of GS in the oral mucosa remains unknown. In this study, we thus investigated the expression of infiltrating lymphocyte subsets (CD3, CD20, CD4, and CD8) and T helper (Th) cytokines including interferon (IFN)-γ (Th1 type), interleukin (IL)-4 (Th2 type), IL-17 (Th17 type), and IL-10 (regulatory T cell type) by immunohistochemistry in buccal mucosa specimens from 2 GS patients compared with 15 OLP patients. All patients showed a predominance of CD3 T cells over CD20 B cells, and CD4 Th cells over CD8 cytotoxic T cells. This polarization was especially prominent in GS. IFN-γ and IL-10 were strongly detected in the infiltrating lymphocytes of all patients. However, IL-4 and IL-17 were detected in OLP patients only. These results suggest that the pathogenesis of GS is different from that of OLP. GS is a unique inflammatory disorder characterized by dysfunction of Th2 and Th17 immune reactions via abnormal T-B cell interaction.

Biological characterization and analysis of metastasis-related genes in cell lines derived from the primary lesion and lymph node metastasis of a squamous cell carcinoma arising in the mandibular gingiva.

Controlling metastatic lesions is an important part of improving cancer prognosis, in addition to controlling the primary lesion. There have been numerous histological studies on primary and metastatic lesions, but little basic research has been performed using cell lines from primary and metastatic lesions belonging to the same patient. In this study, we successfully established a cell line derived from lower gingival carcinoma (WK2) as well as a line derived from secondary cervical lymph node metastasis (WK3F) through primary cultures of tissue from a patient with oral squamous cell carcinoma. We then investigated the biological characteristics of the cancer cell lines from these primary and metastatic lesions and analyzed metastasis-related genes. Comparison of the biological characteristics in vitro showed that WK3F had higher cell proliferation ability and shorter cell doubling time than WK2. WK3F also had increased cell migratory ability and higher invasive and self-replication abilities. Heterotransplantation into nude mice resulted in high tumor formation rates in the tongue and high metastasis rates in the cervical lymph nodes. Changes in WK2 and WK3F gene expression were then comprehensively analyzed using microarrays. Genes with increased expression in WK3F compared to WK2 were extracted when the Z-score was ≥2.0 and the ratio was ≥5.0, while genes with reduced expression in WK3F compared to WK2 were extracted when the Z-score was ≤-2.0 and the ratio was ≤0.2; differences were found in 604 genes. From these, MAGEC1 (88.0-fold), MMP-7 (18.6-fold), SNAI1 (6.6-fold), MACC1 (6.2-fold), and HTRA1 (0.012-fold) were selected as metastasis-related candidate genes. The results suggest that these molecules could be important for clarifying the mechanisms that regulate metastasis and provide new therapeutic targets for inhibiting tumor invasion.

Clinical characteristics of Mikulicz's disease as an IgG4-related disease.

OBJECTIVES: Mikulicz's disease (MD) was considered to be a subtype of Sjögren's syndrome (SS), based on histopathological similarities. However, recent studies have indicated that patients with MD show high serum IgG4 concentration, and suggested that MD is one of "IgG4-related disease" and distinguishable from SS. Therefore, we clinically and histopathologically examined the disease states of MD and SS in detail. MATERIALS AND METHODS: Twenty patients with Mikulicz's disease and 18 with SS were comparatively studied to determine clinical characteristics in MD patients. RESULTS: Sialography in MD patients did not show the "apple-tree sign" typically seen in SS. Serologically, high serum IgG4 levels but not anti-SS-A or anti-SS-B antibodies were observed in MD. SS showed lymphocytic infiltration of various subsets with atrophy or severe destruction of the acini, while MD showed selective infiltration of IgG4+ plasma cells with hyperplastic germinal centers and mild acini destruction. Corticosteroid treatment of MD reduced IgG and IgG4 levels and improved salivary function. A negative correlation between disease duration and increasing rate of salivary flow was observed in MD. CONCLUSIONS: These results suggested that the pathogenesis of MD might be different from those of SS. CLINICAL RELEVANCE: early diagnosis and treatment of MD is important for the improvement of salivary function.

Expression analysis of the spi gene in the pock-forming plasmid pSA1.1 from Streptomyces azureus and localization of its product during differentiation.

The sporulation inhibitory gene spi in the pock-forming conjugative plasmid pSA1.1 of Streptomyces azureus was introduced into cells via a high or low copy number vector to examine the effect of gene dosage on the growth of Streptomyces lividans TK24 as a host. In transformants carrying a high spi copy number, nutrient mycelial growth was inhibited, as was morphological differentiation from substrate mycelium to aerial mycelium on solid media. The degree of inhibition depended on the spi gene dosage, but the presence of pSA1.1 imp genes, which encode negative repressor proteins for spi, relieved the inhibition. Confocal images of Spi tagged with enhanced green fluorescent protein in cells on solid media revealed that spi expression was initiated at the time of elongation of substrate mycelium, that its expression increased dramatically at septation in aerial hyphae, and that the expression was maximal during prespore formation. Expression of spi covered the whole of the hyphae, and the level of expression at the tip of the hyphae during prespore formation was about sixfold greater than during substrate mycelial growth and threefold greater than during aerial mycelial growth. Thus, localized expression of spi at particular times may inhibit sporulation until triggering imp expression to repress its inhibitory effects.

Regulated interaction of protein phosphatase 1 and protein phosphatase 2A with phospholipase C-related but catalytically inactive protein.

Protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) are major members of the protein serine/threonine phosphatase families. We have identified PP1 and PP2A as interacting partners of PRIP (phospholipase C-related but catalytically inactive protein), a protein isolated in our laboratory. We first investigated the interaction of PRIP with two phosphatases, using purified recombinant proteins. PRIP immobilized on beads pulled down the catalytic subunits of both PP1 and PP2A, indicating that the interactions were in a direct manner, and the binding of PP1 and the binding of PP2A to PRIP were mutually exclusive. Site-directed mutagenesis experiments revealed that the binding sites for PP1 and PP2A on PRIP were not identical, but similar. Phosphorylation of PRIP by protein kinase A (PKA) resulted in the weakened binding of PP1, but not PP2A. Rather, the dissociation of PP1 from PRIP by phosphorylation accompanied the strengthened binding of PP2A in in vitro experiments. This regulation of binding of PP1 and PP2A to PRIP by PKA-dependent phosphorylation was also observed in living cells treated with forskolin or isoproterenol. These results suggested that PRIP directly interacts with the catalytic subunits of two distinct phosphatases in a mutually exclusive manner and the interactions are regulated by phosphorylation, thus functioning as a scaffold to regulate the activities and subcellular localizations of both PP1 and PP2A in phospho-dependent cellular signaling.

Sonographic diagnosis for Mikulicz disease.

OBJECTIVE: The aim was to investigate the diagnostic imaging characteristics of Mikulicz disease (MD), especially sonographic ones, and to clarify the differences between them and those in Sjögren syndrome (SS), based on new criteria of MD. STUDY DESIGN: The sonographic and sialographic images, as well as clinical, histopathologic, and serologic findings of 9 patients satisfying the new criteria of MD were analyzed and compared with those in SS. RESULTS: All swollen submandibular glands showed bilateral nodal hypoechoic areas with high vascularization on sonograms and a parenchymal defect on sialograms, whereas parotid glands showed normal or slight change on both images. Nodal areas in submandibular gland sonograms were unclear on computerized tomography and on magnetic resonance imaging, but showed accumulation on gallium scintigraphy. CONCLUSION: Mikulicz disease showed a high rate of bilateral nodal change in submandibular glands, which was completely different from SS. For detection and follow-up of these changes, sonography may be the best imaging modality.

Inflammatory stimuli accelerate Sjögren's syndrome-like disease in (NZB x NZW)F1 mice.

OBJECTIVE: This study was undertaken to determine whether induction of systemic inflammation accelerates the development of Sjögren's syndrome (SS) in genetically susceptible mice. METHODS: Female (NZB x NZW)F1 mice were treated with either Freund's incomplete adjuvant (IFA) or phosphate buffered saline (PBS) at monthly intervals. Salivary gland function was monitored by measuring pilocarpine-induced saliva volume. Mice were killed at different time points and examined for sialadenitis and salivary gland-infiltrating cells. Sera were analyzed for autoantibodies to salivary gland antigens, nuclear antigens, and Ro60. RESULTS: While IFA-treated mice had significantly decreased salivary secretion 7 weeks after the initial treatment, salivary secretion did not decrease in PBS-treated controls until 17 weeks. At 7 weeks, the severity of sialadenitis and the number of T and B cells infiltrating the salivary glands did not differ between the 2 groups. However, at this time point IFA-treated mice showed significantly higher frequencies of CD11clow, B220+, Ly6C+, mouse PDCA-1+ dendritic cells (DCs) in the salivary glands. While levels of autoantibodies did not differ between the 2 groups at early time points, by late time points IFA-treated mice had higher levels. The gland dysfunction observed in IFA-treated mice at earlier time points did not correlate with the severity of sialadenitis or levels of autoantibodies. Instead, it was associated with increased frequency of plasmacytoid DCs in the gland. CONCLUSION: Our data suggest that generalized inflammatory stimuli can accelerate the development of SS-like disease in (NZB x NZW)F1 mice, and that gland dysfunction in SS can develop prior to the generation of a robust adaptive autoimmune response.

Sonographic diagnosis of Sjögren syndrome: evaluation of parotid gland vascularity as a diagnostic tool.

OBJECTIVE: To evaluate the usefulness of the vascularity in parotid glands in sonographic diagnosis for Sjögren syndrome. STUDY DESIGN: Sonographic images of 72 cases of previously suspected Sjögren syndrome (including 43 actual cases) were analyzed retrospectively for the abnormal vascularity in the parotid gland parenchyma. The relationships between the vascularity and the results of sialographic, serologic, and histopathologic examinations were analyzed. We also compared the diagnostic accuracy of B-mode only with that of B-mode plus Doppler-mode. RESULTS: Sjögren-positive cases showed significantly higher vascularity. As the grade of vascularity became higher, the rate of the Sjögren-negative cases became lower. The highest mean vascular score could be observed both in the initial stage and in the cavitary-destructive stage in the sialographic grades. Sensitivity and accuracy were markedly improved with vascular information. CONCLUSION: By using vascular information, sonographic diagnosis for Sjögren syndrome can be improved.

Severe focal sialadenitis and dacryoadenitis in NZM2328 mice induced by MCMV: a novel model for human Sjögren's syndrome.

The genetic and environmental factors that control the development of Sjögren's syndrome, an autoimmune disease mainly involving the salivary and lacrimal glands, are poorly understood. Viruses which infect the glands may act as a trigger for disease. The ability of sialotropic murine CMV (MCMV) to induce acute and chronic glandular disease was characterized in an autoimmune-prone mouse strain, NZM2328. MCMV levels were detectable in the salivary and lacrimal glands 14-28 days after i.p. infection and correlated with acute inflammation in the submandibular gland. After latency, virus was undetectable in the glands by PCR. At this stage, NZM2328 female mice developed severe chronic periductal inflammation in both submandibular and lacrimal glands in contrast to the much milder infiltrates found in female B6-lpr and male NZM2328. The focal infiltrates consisted of CD4+ and B220+ cells as opposed to diffuse CD4+, CD8+, and B220+ cells during acute infection. Salivary gland functional studies revealed a gender-specific progressive loss of secretory function between days 90 and 125 postinfection. Latent MCMV infection did not significantly affect the low incidence of autoantibodies to Ro/SSA and La/SSB Ags in NZM2328 mice. However, reactivities to other salivary and lacrimal gland proteins were readily detected. MCMV infection did not significantly alter the spontaneous onset of kidney disease in NZM2328. Thus, chronic inflammation induced by MCMV with decreased secretory function in NZM2328 mice resembles the disease manifestations of human Sjögren's syndrome.

Sonographic diagnostic criteria for screening Sjögren's syndrome.

OBJECTIVE: The objective of this study is to establish readily applied sonographic diagnostic criteria for Sjögren's syndrome. STUDY DESIGN: Sonographic images of 79 cases of previously suspected Sjögren's syndrome (including 43 actual cases) were analyzed retrospectively for the following characteristic features: (1) multiple hypoechoic areas, (2) multiple hyperechoic lines or spots, (3) multiple hypoechoic areas surrounded with hyperechoic lines or spots, and (4) obscuration of the gland configuration. Logistic regression analysis was used to extract valuable sonographic findings. Sonographic images of 80 prospective patients (of whom 48 proved to have Sjögren's syndrome) were scored prospectively using selected features to verify the usefulness of the established criteria. RESULTS: Three sonographic findings in parotid and submandibular glands were selected by logistic regression analysis and retrospective and prospective patients compared. Experienced observers could differentiate positive cases of Sjögren's syndrome from negative controls to a highly significant degree. Findings correlated very well with sialographic grading. CONCLUSION: Sonography can be substituted for sialography when applying the selected criteria in screening for Sjögren's syndrome.

Evidence for multiple shared antigenic determinants within Ro60 and other lupus-related ribonucleoprotein autoantigens in human autoimmune responses.

Ab responses directed against several ribonucleoprotein (RNP) Ags are a characteristic feature of systemic lupus erythematosus (SLE). Previous work in our laboratory using mouse model systems had revealed that both epitope spreading and inherent cross-reactivity between ribonucleoproteins contributes to the observed multiple specificities in autoimmune sera. We have now extended these studies to human autoimmune responses. Using purified polyclonal and mAbs derived from SLE patients, cross-reactivity between Ro60 and SmD was demonstrated. The cross-reactive epitope was mapped to nonhomologous regions on Ro60(481-505) and SmD(88-102). Five mAbs specifically recognized apoptotic cells, demonstrated variable levels of cross-reactivity toward other nonhomologous ribonucleoprotein targets and bound multiple, nonoverlapping and nonhomologous epitopes on Ro60. Our study demonstrates that cross-reactivity between frequently targeted autoantigens is an important aspect of human systemic autoimmune responses. The presence of multiple cross-reactive epitopes on Ro60 might be important for the generation of anti-Ro60 Ab in SLE patients and in normal individuals displaying no evidence of clinical disease.