Correlation between salivary and serum anti-desmoglein 1 and 3 antibody titres using ELISA and between anti-desmoglein levels and disease severity in pemphigus vulgaris.

ELISA for anti-desmoglein antibodies (Dsg) is commonly used for diagnosis and assessment of treatment response in pemphigus vulgaris (PV). The present study was conducted to assess the relationship between salivary and serum Dsg1 and Dsg3 levels, and whether salivary Dsg1 and Dsg3 levels correlate with clinical disease severity of oral mucosal lesions in PV. In total 43, patients with PV with predominantly mucosal involvement were recruited. Both serum and salivary samples were collected from the cases, and salivary samples were also collected from five controls. There was a statistically significant correlation between serum and salivary Dsg1 levels and between serum and salivary Dsg3 levels. There was no correlation between serum or salivary Dsg1 and Dsg3 levels with the objective component of the oral mucosal Autoimmune Bullous Skin Disorder Intensity Score (ABSIS). Serum Dsg1 levels significantly correlated with cutaneous ABSIS, but there was no correlation between cutaneous ABSIS and either salivary Dsg1, salivary Dsg3 or serum Dsg3. As salivary Dsg titres correlate with serum levels, saliva can serve as a simple and noninvasive alternative to serum for Dsg ELISA.

Prognostic significance of DSG3 in rectal adenocarcinoma treated with preoperative chemoradiotherapy.

AIM: This study aimed to investigate the prognostic significance of DSG3 and its association with response to neoadjuvant concurrent chemoradiotherapy (CCRT) in rectal cancer. MATERIALS & METHODS: Data mining of a publicly available dataset was performed to find genes associated with CCRT response. Immunohistochemistry was applied to evaluate DSG3 expression. The relationships between DSG3 expression and various clinicopathological parameters and survival were analyzed. RESULTS: The DSG3 gene was significantly associated with CCRT response. The expression of DSG3 negatively correlated with poorer tumor regression (p < 0.001) and had an independent negative impact on disease-specific survival (p = 0.011), local recurrence-free survival (p = 0.031) and metastasis-free survival (p = 0.029). CONCLUSION: DSG3 was a key prognostic factor and predictor for CCRT response in rectal cancer patients.

E-cadherin and Src associate with extradesmosomal Dsg3 and modulate desmosome assembly and adhesion.

Desmosomes provide strong intercellular cohesion essential for the integrity of cells and tissues exposed to continuous mechanical stress. For desmosome assembly, constitutively synthesized desmosomal cadherins translocate to the cell-cell border, cluster and mature in the presence of Ca(2+) to stable cell contacts. As adherens junctions precede the formation of desmosomes, we investigated in this study the relationship between the classical cadherin E-cadherin and the desmosomal cadherin Desmoglein 3 (Dsg3), the latter of which is indispensable for cell-cell adhesion in keratinocytes. By using autoantibodies from patients with the blistering skin disease pemphigus vulgaris (PV), we showed in loss of function studies that E-cadherin compensates for effects of desmosomal disassembly. Overexpression of E-cadherin reduced the loss of cell cohesion induced by PV autoantibodies and attenuated activation of p38 MAPK. Silencing of E-cadherin abolished the localization of Dsg3 at the membrane and resulted in a shift of Dsg3 from the cytoskeletal to the non-cytoskeletal protein pool which conforms to the notion that E-cadherin regulates desmosome assembly. Mechanistically, we identified a complex consisting of extradesmosomal Dsg3, E-cadherin, ß-catenin and Src and that the stability of this complex is regulated by Src. Moreover, Dsg3 and E-cadherin are phosphorylated on tyrosine residues in a Src-dependent manner and Src activity is required for recruiting Dsg3 to the cytoskeletal pool as well as for desmosome maturation towards a Ca(2+)-insensitive state. Our data provide new insights into the role of E-cadherin and the contribution of Src signaling for formation and maintenance of desmosomal junctions.

Desmoglein 3 and p40 immunoreactivity in neoplastic and nonneoplastic thymus: a potential adjunct to help resolve selected diagnostic and staging problems.

The potential usefulness of the squamous markers p40 and desmoglein 3 (DSG-3) for the diagnosis and staging of selected thymic lesions is uncertain. We investigated their expression and distribution pattern in 66 thymomas, 12 thymic squamous carcinomas, 6 undifferentiated thymic carcinomas, 5 hyperplastic thymi, and 5 normal thymi. p40 nuclear and DSG-3 cytoplasmic/membranous immunoreactivity in greater than or equal to 10% of thymic epithelial cells was interpreted as positive, and DSG-3 distribution pattern was classified as organotypic and nonorganotypic. All nonneoplastic thymic tissues, 100% of thymic squamous carcinomas, 97% of thymomas, and 50% of undifferentiated thymic carcinomas were positive for p40. Expression of p40 in almost all thymomas and in 50% of undifferentiated carcinomas that lacked squamous features suggests that p40 is not a good marker for the diagnosis of thymic squamous carcinoma. All normal and hyperplastic thymi, 51.5% of thymomas, and 0% of thymic squamous carcinomas expressed DSG-3 in an organotypic pattern, and 13.6% of thymomas and 83% of thymic squamous carcinomas were DSG-3 positive in a nonorganotypic pattern. Findings suggest that nonorganotypic DSG-3 expression favors the diagnosis of squamous cell carcinoma over thymoma. In 26 (60.5%) of the 43 cases where neoplastic and nonneoplastic thymus were present on the same slide, the presence/absence or distribution pattern of DSG-3 immunoreactivity was different in the 2 components, suggesting that this marker can be helpful in staging thymomas with incomplete encapsulation. The presence of DSG-3-positive and DSG-3-negative thymomas raises the possibility that these tumors may originate from 2 different types of thymic epithelial cells.

[D-penicillamine-induced pemphigus: changes in anti-32-2B immunostaining patterns]. / Autonomisation d'un pemphigus induit par la D-pénicillamine: évolution de l'immunomarquage par l'anticorps anti-32-2B.

BACKGROUND: It has been reported that D-penicillamine causes pemphigus that is typically superficial. Immunostaining with monoclonal anti-32-2B antibody targeting desmoglein 1 and 3 can help differentiate between drug-induced and classical auto-immune pemphigus. Absence of specific staining militates in favour of drug-induced pemphigus whilst positive staining suggests an auto-immune aetiology that is ongoing despite discontinuation of drug therapy. PATIENTS AND METHODS: A 59-year-old male patient was referred for management of superficial pemphigus 1 year after starting D-penicillamine treatment for scleroderma. The diagnosis of pemphigus was confirmed histologically (intra-epidermal cleavage, acantholysis and perikeratinocytes, deposition of IgG and complement C3). Immunochemical staining with anti-32-2B antibody was initially normal, in keeping with drug-induced pemphigus. Despite discontinuation of D-penicillamine, pemphigus recurred in 2008. A further skin biopsy was undertaken and anti-32-2B staining was abnormal, which is consistent with auto-immune pemphigus. DISCUSSION: Numerous cases of drug-induced pemphigus have been described in the literature. In approximately half of all cases, the pemphigus recedes after cessation of the causative drug. However, there have been no previous reports that changes over time in the immunostaining with anti-32-2B antibodies can mirror a change in form of pemphigus from a drug-induced type to an idiopathic type as well as the associated clinical feature of persistence after drug withdrawal. CONCLUSION: Normal staining with anti-32-2B antibody is associated with a favourable prognosis as regards resolution of drug-induced pemphigus. When, as in this case, status changes to abnormal staining, there is a risk that the pemphigus may become chronic despite discontinuation of therapy.

Comparative Transcriptome Analysis Identifies Desmoglein-3 as a Potential Oncogene in Oral Cancer Cells.

The role of desmoglein-3 (DSG3) in oncogenesis is unclear. This study aimed to uncover molecular mechanisms through comparative transcriptome analysis in oral cancer cells, defining potential key genes and associated biological processes related to DSG3 expression. Four mRNA libraries of oral squamous carcinoma H413 cell lines were sequenced, and 599 candidate genes exhibited differential expression between DSG3-overexpressing and matched control lines, with 12 genes highly significantly differentially expressed, including 9 upregulated and 3 downregulated. Genes with known implications in cancer, such as MMP-13, KRT84, OLFM4, GJA1, AMOT and ADAMTS1, were strongly linked to DSG3 overexpression. Gene ontology analysis indicated that the DSG3-associated candidate gene products participate in crucial cellular processes such as junction assembly, focal adhesion, extracellular matrix formation, intermediate filament organisation and keratinocyte differentiation. Validation of RNA-Seq was performed through RT-qPCR, Western blotting and immunofluorescence analyses. Furthermore, using transmission electron microscopy, we meticulously examined desmosome morphology and revealed a slightly immature desmosome structure in DSG3-overexpressing cells compared to controls. No changes in desmosome frequency and diameter were observed between the two conditions. This study underscores intricate and multifaceted alterations associated with DSG3 in oral squamous carcinoma cells, implying a potential oncogenic role of this gene in biological processes that enable cell communication, motility and survival.

Pemphigus vulgaris antigen mRNA quantification for the staging of sentinel lymph nodes in head and neck cancer.

BACKGROUND: Molecular diagnosis has been proposed to enhance the intra-operative diagnosis of sentinel lymph node (SLN) invasion in head and neck squamous cell carcinoma (HNSCC). Although cytokeratin (CK) mRNA quantification with real-time reverse transcriptase-PCR (QRT-PCR) has produced encouraging results, the more discriminating markers remain to be identified. METHODS: Pemphigus vulgaris antigen (PVA), squamous cell carcinoma antigen (SCCA), and CK17 mRNA were quantified using QRT-PCR, and the results were compared with an extensive histopathological examination of the entire SLNs on 78 SLNs harvested from 22 patients with HNSCC. RESULTS: SCCA and CK17 quantification showed significantly higher mRNA values for macrometastases (MAs) than for either negative or isolated tumour cell (ITC) SLNs (P<0.01). Pemphigus vulgaris antigen allowed the discrimination of all MAs and micrometastases from both negative and ITC SLNs (P<0.001). For the neck staging of patients, considering metastatic vs non-metastatic status, receiver-operating characteristic curve analysis found areas under the curve of 93.8, 97.9, and 100% for CK17, SCCA, and PVA, respectively. With PVA, a cutoff value of 562 copies per 100 ng of cDNA permitted the correct distinction between patients with positive as opposed to negative neck nodes in all cases. CONCLUSION: PVA seems to be a highly promising marker for accurate intra-operative SLN staging in HNSCC by QRT-PCR.

Searching for foreign antigens as possible triggering factors of autoimmunity: Torque Teno virus DNA prevalence is elevated in sera of patients with bullous pemphigoid.

OBJECTIVE: The Torque Teno virus (TTV), a member of virus genus Anellovirus has been shown to be commonly present in humans, yet without detectable pathogenicity. Recent studies imply that TTV may contribute to provoke autoimmune progresses in systemic lupus erythematosus and idiopathic inflammatory myopathies. We aimed to study the presence of TTV in a group of patients with autoimmune bullous diseases with a further goal to identify long-lasting foreign antigen, such as TTV as possible triggers of skin-specific autoimmunity. PATIENTS AND METHODS: We performed in silico research to study similarities between known TTV sequences and antigens of bullous pemphigoid (BP), pemphigus vulgaris (PV) and dermatitis herpetiformis (DH). Basic Local Alignment Search Tool results showed matching regions for the major BP antigens BP180 and BP230, PV antigen desmoglein 3 and DH antigen transglutaminase 3 and disclosed overlapping, antigen-predicted sequences only for BP180 regions. We also assessed the prevalence of TTV in these disorders and compared them with the results from two healthy blood donor groups (group 1: sex- and age-matched for the general bullous group, n = 95; group 2: sex- and age-matched for BP, n = 50). Furthermore, we assayed lymphocytes from four TTV DNA and BP180 NC16A blot-positive BP patients and three controls in a standard lymphocyte transformation test with a TTV peptide from the conserved ORF(Open Reading Frame)1/N22 region. RESULTS: We found that the detection rate of TTV was comparable with that in healthy controls in the group of PV (19/33); whereas detection rates in DH showed a slight, but not significant tendency for elevation (17/20). Contrary, the TTV prevalence in BP patients was significantly elevated (group 1: 36/40 vs group 2: 31/50, P < 0.032). Lymphocytes from all four virus-positive BP patients heavily reacted to TTV peptide while two of the three healthy controls have shown not to recognize the viral sequences. Only the TTV carrier healthy control had a minor reaction at lowest peptide concentration. The combined in silico, polymerse chain reaction and in vitro cell assay data of the present study indicate that a TTV persistence may contribute to the pathogenesis of BP.

Nikolsky's sign on the gingival mucosa: a clinical tool for oral health practitioners.

BACKGROUND: Nikolsky's sign is a clinical sign which is elicited by a horizontal, tangential pressure to the mucosa and/or skin resulting in blisters extending and separating or peeling away. Few data are currently available in the literature about its usefulness, specificity, and sensitivity in the diagnosis of either oropharyngeal or cutaneous bullous diseases. The purpose of this study was to determine the sensitivity and specificity of the gingival Nikolsky's sign in the identification of an autoimmune blistering disease. METHODS: Over a period of 13 years, we recruited 566 patients with autoimmune oral bullous and non-bullous diseases who possessed either maxillary or mandibular gingival mucosal lesions. All patients were subjected to a test causing a gingival Nikolsky's sign at their first visit during the diagnostic algorithm and in the active disease phase before commencing treatment. RESULTS: A total of 566 patients (184 with and 382 without bullous lesions) had at least gingival involvement. A positive gingival Nikolsky's sign resulted in 100 (17.7%) of 566 patients: 86 patients with bullous lesions (53 with pemphigus vulgaris, eight with mucous membrane pemphigoid, 22 with bullous/mixed lichenoid lesions, and three with erythema multiforme) and 14 with non-bullous lesions (12 with non-bullous lichenoid lesions and two with systemic lupus erythematous/mixed connective tissue disease). Thus, the specificity of Nikolsky's sign was higher (96.3%) than the sensitivity (46.7%). CONCLUSION: The results of this study support the use of Nikolsky's sign of the gingival mucosa as a viable test to establish the presence of oral bullous diseases.

Desmoglein 3 as a prognostic factor in lung cancer.

Desmoglein 3 is a desmosomal protein of the cadherin family. Our cDNA expression profile demonstrated that desmoglein 3 was highly expressed in squamous cell carcinoma of the lung but not detected in pulmonary adenocarcinoma or normal lung. To investigate the clinical significance of desmoglein 3 in lung cancer, we surveyed its expression in primary non-small-cell lung cancers and neuroendocrine tumors. We used immunohistochemical analysis to examine the expression of desmoglein 3 by using tissue microarrays containing samples from 300 surgical non-small-cell lung cancer and 183 lung neuroendocrine tumor. Staining status was determined based on the sum of the distribution score (0, 1, or 2) and the intensity score (0, 1, 2, or 3) of the staining signal. Follow-up was available for 346 cases (median follow-up of 2.8 years). We determined the survival statistical significance of desmoglein 3 by using the log-rank test, and we plotted Kaplan-Meier curves. Negative immunohistochemical staining with desmoglein 3 was associated with shorter survival for all lung cancer patients regardless of the histologic subtype (5-year survival of 20.9% versus 49.5%, P < .001) in our series. In patients with atypical carcinoid tumors, lacking desmoglein 3 expression showed a 5-year survival of 0% compared with 36.8% for desmoglein 3-positive cases (P < .001). Desmoglein 3 status indicated a poor prognosis in lung cancers and portends a more aggressive behavior for atypical carcinoid tumors.

Paraneoplastic pemphigus mimicking erosive mucosal lichen planus associated with primary hepatocellular carcinoma.

A 58-year-old Japanese male visited us with painful lesions on the lower lip, oral mucosa and genital region of an 8-month duration. Histological features of the genital lesion were almost consistent with lichenoid tissue reaction. A few intraepidermal acantholytic keratinocytes were also seen in the suprabasal clefts. Direct immunofluorescence exhibited cell surface immunoglobulin (Ig)G deposition and linear deposition of fibrinogen at the dermoepidermal junction. IgG anti-desmoglein (Dsg)3 antibody, but not anti-Dsg1 antibody, was detected in the patient's serum by enzyme-linked immunosorbent assay. Immunoblotting using normal human epidermal extract detected the 210-kD envoplakin, 190-kD periplakin and 130-kD Dsg3. The diagnosis of paraneoplastic pemphigus (PNP) was made. Subsequent investigation revealed a large space-occupying lesion in the liver. Histological findings from liver biopsy specimen were consistent with hepatocellular carcinoma. The patient has been alive 38 months after the diagnosis of PNP was made, although the liver mass has slowly enlarged. Our case is clinically and histologically similar to erosive mucosal lichen planus. Immunological studies confirmed the diagnosis of PNP. The results of negative Dsg1 and positive Dsg3 were consistent with clinical features showing severe mucosal involvement without cutaneous erosion. In PNP, the association with non-hematological solid tumor is extremely rare.

Four cases of mucous membrane pemphigoid with clinical features of oral lichen planus.

BACKGROUND: Mucous membrane pemphigoid (MMP) and oral lichen planus (OLP) show similar clinical features on the oral mucosa. As clinical manifestations of oral mucosal lesions, MMP shows blisters and erosions, whereas OLP shows lace-like whitish lesions in an annular arrangement with erythema and erosions. Histopathologically, MMP shows subepithelial bullae with infiltrates of lymphocytes and neutrophils, whereas OLP shows band-like interface infiltration of lymphocytes with damage in basal cells. However, these two diseases are frequently difficult to distinguish both clinically and histopathologically. OBJECTIVES: We report four patients with oral MMP who showed OLP-like clinical and histopathological lesions. METHODS: We performed direct immunofluorescence, indirect immunofluorescence of normal human skin and 1 m NaCl-split skin, enzyme-linked immunosorbent assays for BP180, BP230, and desmogleins 1 and 3, and immunoblotting of normal human epidermal and dermal extracts, recombinant proteins of BP180-NC16a and -C-terminal domains, concentrated culture supernatant of HaCaT cells, and purified laminin-332. RESULTS: The results of various immunological studies suggested the diagnoses of various types of MMP for all four patients. CONCLUSIONS: Because MMP and OLP require different treatments, all dentists and dermatologists should have knowledge about the disease entity and the serological diagnostic methods for various types of MMP.

The value of trichoscopy in the differential diagnosis of scalp lesions in pemphigus vulgaris and pemphigus foliaceus.

BACKGROUND: Trichoscopy is becoming increasingly popular in diagnosing hair and scalp diseases. Scalp involvement in pemphigus is common. The scalp may be the first or only site of clinical manifestation of the disease. OBJECTIVE: The aim of this study was to analyze whether trichoscopy may be useful in aiding differential diagnosis of scalp lesions in patients with pemphigus vulgaris and pemphigus foliaceus. METHODS: Trichoscopy was performed in 19 patients with scalp lesions in the course of pemphigus (9 patients with pemphigus vulgaris and 10 with pemphigus foliaceus). In all patients, the diagnosis of scalp pemphigus was confirmed by histopathology. The working magnification was 20-fold and 70-fold. RESULTS: The most frequently observed trichoscopy features of pemphigus lesions were: extravasations (18/19; 94.7%) and yellow hemorrhagic crusts (11/19; 57.9%). Yellow dots with whitish halo were observed in 6/19 (31.6%) patients with pemphigus. White polygonal structures were observed in pemphigus foliaceus (6/10; 60%), but not in pemphigus vulgaris. Vascular abnormalities were more frequent in pemphigus vulgaris, when compared to pemphigus foliaceus, and were associated with a severe course of disease. Linear serpentine vessels were the most frequent vascular abnormality in patients with pemphigus vulgaris and pemphigus foliaceus (77.8% and 30%, respectively). CONCLUSION: Trichoscopy may serve as a useful supplementary method in the differential diagnosis of pemphigus, especially in cases of desquamative or exudative lesions limited to the scalp. Extravasations, yellow hemorrhagic crusts, yellow dots with whitish halo, white polygonal structures and linear serpentine vessels are trichoscopy features which may suggest the diagnosis of pemphigus.

Tissue-engineered mucosa is a suitable model to quantify the acute biological effects of ionizing radiation.

The aim of this study was to evaluate the suitability of tissue-engineered mucosa (TEM) as a model for studying the acute effects of ionizing radiation (IR) on the oral mucosa. TEM and native non-keratinizing oral mucosa (NNOM) were exposed to a single dose of 16.5Gy and harvested at 1, 6, 24, 48, and 72h post-irradiation. DNA damage induced by IR was determined using p53 binding protein 1 (53BP1), and DNA repair was determined using Rad51. Various components of the epithelial layer, basement membrane, and underlying connective tissue were analyzed using immunohistochemistry. The expression of cytokines interleukin-1ß (IL-1ß) and transforming growth factor beta 1 (TGF-ß1) was analyzed using an enzyme-linked immunosorbent assay. The expression of DNA damage protein 53BP1 and repair protein Rad51 were increased post-irradiation. The expression of keratin 19, vimentin, collage type IV, desmoglein 3, and integrins α6 and ß4 was altered post-irradiation. Proliferation significantly decreased at 24, 48, and 72h post-irradiation in both NNOM and TEM. IR increased the secretion of IL-1ß, whereas TGF-ß1 secretion was not altered. All observed IR-induced alterations in TEM were also observed in NNOM. Based on the similar response of TEM and NNOM to IR we consider our TEM construct a suitable model to quantify the acute biological effects of IR.

Assessment of desmosomal components (desmoglein 1-3, plakoglobin) in cardia mucosa in relation to gastroesophageal reflux disease and Helicobacter pylori infection.

Gastroesophageal reflux disease is associated with impaired epithelial barrier function and abnormal expression of proteins forming cell-cell contacts by tight junctions and desmosomes in distal esophageal squamous mucosa. Although gastroesophageal reflux disease and Helicobacter pylori are both associated with chronic inflammation of the adjacent cardia mucosa, it is not known whether these lead to derangements of the desmosomal complexes. Here, we assessed the expression of 4 proteins (plakoglobin and desmoglein 1, 2, and 3) forming epithelial desmosomal complexes by quantitative reverse transcription polymerase chain reaction and immunohistochemistry in biopsies from 67 patients with gastroesophageal reflux disease and 23 gastroesophageal reflux disease-negative controls. Plakoglobin and desmoglein 2 were ubiquitously expressed in all samples, whereas desmoglein 1 and 3 were not expressed in cardia mucosa. Gastroesophageal reflux disease was specifically associated with elevated transcript levels of desmoglein 2 and plakoglobin. These were significantly increased from 2.0- to 2.7-fold in patients with gastroesophageal reflux disease compared with controls (P < .01), and significantly increased immunohistochemical scores for both proteins were observed (P < .05) as well. The combined presence of gastroesophageal reflux disease and Helicobacter pylori infection had no additional effect on desmosomal gene expression. Taken together, the up-regulation of plakoglobin and desmoglein 2 in cardia mucosa of patients with gastroesophageal reflux disease supports the concept that the "transition zone" between distal esophagus and proximal stomach is affected by gastroesophageal reflux disease as well, and architectural and molecular changes in the desmosomal compartment contribute to the pathogenesis of gastroesophageal reflux disease in the cardia mucosa.

Quantitative analysis of human keratinocyte cell elasticity using atomic force microscopy (AFM).

We present the use of atomic force microscopy (AFM) to visualize and quantify the dynamics of epithelial cell junction interactions under physiological and pathophysiological conditions at the nanoscale. Desmosomal junctions are critical cellular adhesion components within epithelial tissues and blistering skin diseases such as Pemphigus are the result in the disruption of these components. However, these structures are complex and mechanically inhomogeneous, making them difficult to study. The mechanisms of autoantibody mediated keratinocyte disassembly remain largely unknown. Here, we have used AFM technology to image and measure the mechanical properties of living skin epithelial cells in culture. We demonstrate that force measurement data can distinguish cells cultured with and without autoantibody treatment. Our demonstration of the use of AFM for in situ imaging and elasticity measurements at the local, or tissue level opens potential new avenues for the investigation of disease mechanisms and monitoring of therapeutic strategies in blistering skin diseases.

Desmoglein 3 is overexpressed in inverted papilloma and squamous cell carcinoma of sinonasal cavity.

OBJECTIVES/HYPOTHESIS: We sought to investigate the role of desmoglein 3 in pathogenesis of sinonasal inverted papilloma (IP) and its malignant transformation. METHODS: Fifteen subjects with sinonasal IP and 15 subjects of normal sphenoid sinus mucosa were enrolled. Each specimen was divided into two portions: one for mRNA expression analysis by real-time polymerase chain reaction, and the other for detection of targeted proteins by immunohistochemistry analysis. In addition, another 10 cases of IP with squamous cell carcinoma (SCC) were added for immunohistochemistry analysis. RESULTS: The mRNA expression level of desmoglein 3 was significantly higher in IP tissues than in the normal sinus mucosa (P < .001). In immunohistochemistry study, desmoglein 3 was detected in plasma membrane areas of IP and IP with SCC tissues, but no obvious expression was found in normal sinus mucosa (total score; both P < .001). Positive desmoglein 3 staining was strongly present in nearly all malignant transformation areas of IP with SCC cases (90%), but only in scattered areas of some cases of IP (53%) (total score; P < .001). CONCLUSIONS: Desmoglein 3 was overexpressed in IP and IP with SCC, and the overexpression was correlated with malignant transformation of IP. It may provide valuable insight into the pathobiology of this disease, and can potentially provide a venue to predict malignant transformation in sinonasal IP.

Pathophysiology of nasal polyposis: the role of desmosomal junctions.

BACKGROUND: Many mucosal inflammatory conditions are associated with alterations in epithelial intercellular junctions and barrier function; however, little is known about the role of intercellular junctions in inflammatory diseases of the upper airways. In this study, we examined nasal polyps for altered intercellular junctions and protein expression. METHODS: Biopsy specimens of nasal polyps and normal tissue were obtained intraoperatively from 11 patients and 6 controls. Tissue was analyzed for expression of intercellular junctional proteins by immunofluorescence. In parallel, cultured human bronchial epithelial (HBE) cells were treated with tumor necrosis factor (TNF) alpha, interferon (IFN) gamma, and IL-13 to simulate inflammatory conditions followed by assessment for changes in junctional proteins by immunofluorescence and Western blot. RESULTS: Of the intercellular junctional proteins analyzed, including proteins comprising tight and adherens junctions, the only alterations observed were in desmosomal proteins in nasal polyp epithelium compared with normal controls. Specifically, expression of desmosomal proteins DSG2 and DSG3 were significantly decreased in polyps versus controls (0.53 pixel/microm2 versus 1.09 pixel/microm2 [p = 0.009], and 0.29 pixel/microm2 versus 1.11 pixel/microm2 [p = 0.0078], respectively). In vitro experiments involving exposure of cultured HBE cells with inflammatory cytokines revealed that TNF-alpha treatment resulted in internalization and decreased expression of DSG2 by immunofluorescence and Western blotting. Treatment with IFN-gamma resulted in increased expression of DSG2 and evidence of protein cleavage by Western blot. IL-13 exposure resulted in down-regulation of DSG2 expression and evidence of protein cleavage. CONCLUSION: These results indicate that nasal polyps express decreased levels of DSG2 and DSG3 components of desmosomal junctions. This is likely linked to the mucosal inflammatory response. Exposure of a respiratory cell line to Th1/Th2 cytokines results in similar expressional alterations in DSG2, suggesting protein internalization and cleavage. We speculate that weakened desmosomal junctions in nasal mucosa secondary to inflammatory cytokines may contribute to the formation of nasal polyposis.

P120-catenin is a novel desmoglein 3 interacting partner: identification of the p120-catenin association site of desmoglein 3.

P120-catenin (p120ctn) is an armadillo-repeat protein that directly binds to the intracytoplasmic domains of classical cadherins. p120ctn binding promotes the stabilization of cadherin complexes on the plasma membrane and thus positively regulates the adhesive activity of cadherins. Using co-immunoprecipitation, we show here that p120ctn associates to desmogleins (Dsg) 1 and 3. To determine which region is involved in the association between Dsg3 and p120ctn, we constructed mutant Dsg3 proteins, in which various cytoplasmic subdomains were removed. The tailless Dsg3 constructs Delta IA:AA1-641Dsg3 and Delta 641-714Dsg3, which do not contain the intracellular anchor (IA) region, did not coprecipitate with p120cn, nor did they colocalize at the plasma membrane. Immunocytochemical analysis revealed that p120ctn does not localize to desmosomes, but colocalizes with Dsg3 at the cell surface. A biotinylation assay for Dsg3 showed that biotinylated Delta 641-714Dsg3 was turned over more rapidly than wild-type Dsg3. These results indicate that the membrane proximal region (corresponding to residues 641-714) in the IA region of Dsg3 is necessary for complex formation with p120ctn, and to maintain free Dsg3 at the cell surface before it is integrated into desmosomes. In summary, we show that p120ctn is a novel interactor of the Dsg proteins, and may play a role in desmosome remodeling.