Lytic Epstein-Barr virus infection in epithelial cells but not in B-lymphocytes is dependent on Blimp1.

Epstein-Barr virus (EBV) replicates in superficial differentiated cells of oral hairy leukoplakia (OHL). Differentiation of squamous epithelial cells depends on B-lymphocyte-induced maturation protein 1 (Blimp1). Here we show that expression of the EBV immediate-early protein BZLF1 is restricted to Blimp1-positive epithelial cells in OHL. Luciferase assays revealed Blimp1-dependent induction of the BZLF1 promoter Zp in epithelial cell lines. Expression of ZEB1, a negative regulator of Zp, and of Xbp-1, which mediates the Blimp1 effect on Zp in B-cells, was not affected by enforced Blimp1 expression. Moreover, Xbp-1 protein expression was not detected in differentiated epithelial cells of OHL. Thus, Blimp1 induces BZLF1 expression in epithelial cells independently of ZEB1 and Xbp-1. In contrast to epithelial cells of OHL, BZLF1 expression was also observed in Blimp1-negative lymphoid cells in infectious mononucleosis tonsils, suggesting that EBV replication in B-cells may be induced independently of terminal differentiation.

Candida albicans strain-dependent modulation of pro-inflammatory cytokine release by in vitro oral and vaginal mucosal models.

Candida albicans is a commensal organism at several sites and is a versatile, opportunistic pathogen. The underlying factors of pathogen and host associated with commensalism and pathogenicity in C. albicans are complex and their importance is largely unknown. We aimed to study the responses of oral epithelial (OEM) and vaginal epithelial models (VEM) to infection by oral and vaginal C. albicans strains to obtain evidence of inter-strain differences in pathogenicity and of site-specificity. Following inoculation of models, proinflammatory cytokines IL-1α, IL-1ß, IL-6, IL-8 and prostaglandin E2 (PGE2) release were monitored and histological staining undertaken. Striking differences in strain behaviour and epithelial responses were observed. IL-1α, IL-1ß and IL-8 release were significantly increased from the OEM in response to denture stomatitis strain NCYC 1467. Increased IL-8 release also followed infection of the OEM with both vaginal strains. Overall the VEM was relatively unresponsive to infection with either oral or vaginal strains under these conditions. Adherence and hyphal development were observed for all strains on both models although extensive, uniform tissue penetration was seen only with stomatitis strain NCYC 1467 on the OEM. Candidal strains were assayed for phospholipase (PL) and secreted aspartyl proteinase (SAP) activities where phospholipase (PL) activity was highest for strain NCYC 1467 although highest SAP activity was observed for vaginal strain NCPF 8112 in this assay. This is the first study to concurrently investigate cytokine production from oral and epithelial models using candidal strains originating from these respective mucosal sites from healthy and disease states. These data demonstrate significant differences in inflammatory responses of host epithelia to individual C. albicans strains.

An altered keratinocyte phenotype in oral submucous fibrosis: correlation of keratin K17 expression with disease severity.

Oral submucous fibrosis (OSF) is characterized by abnormal collagen metabolism in the submucosal connective tissue. Its influence on the overlying epithelium is not known but about 14% of OSF cases undergo malignant transformation to squamous cell carcinoma indicating association with abnormality of the epithelium. Here, we have defined the keratin expression profile, by immunohistochemistry and quantitative image analysis, using a panel of 22 anti-keratin monoclonal antibodies on 28 OSF samples. We observed an increase of K1 and K10 in the suprabasal layers, induction of K6 in the basal layer and complete loss of K19 in the epithelium. Furthermore, there was increased K17 expression in the suprabasal layers, which correlated with disease severity. In a subset of the most severe OSF cases (14%), K17 expression was completely lost in the basal layer which might define them to be at most risk to undergo malignant transformation. There was no detectable expression of K8, K18, K7 and K9 and the expression of K4, K13, K14, K15 and K16 did not change in OSF. We propose that the altered keratin profiles could be useful as histological diagnostic markers and provide important insights into the pathogenesis of the disease and its predisposition to malignancy.

Electrically induced transport of macromolecules through oral buccal mucosa.

OBJECTIVE: To investigate the feasibility of iontophoretic delivery of large molecules across buccal mucosa, and to establish its potential for enhanced drug delivery. METHODS: Qualitative (6h) and quantitative (8 and 36 h) assessment of porcine buccal mucosa, using a diffusion cell in vitro model, was carried out by fluorescent microscopy and UV/Vis spectroscopy respectively, with four fluorescently-labeled model species (3 and 10 kDa dextrans, 12 kDa parvalbumin and 66 kDa bovine serum albumin, BSA). Passive and iontophoresis parameters were obtained. The experimental iontophoresis data were compared with theoretical predictions. RESULTS: The two dextrans and parvalbumin showed enhanced permeation through buccal mucosa after anodal iontophoresis (1-6h). Passive diffusion and cathodal iontophoresis resulted in minimal permeation. BSA could not be measured by either mode. Iontophoretic delivery profiles compared to passive delivery, had reduced time lags (30-50 versus ~270 min) and increased flux (~37 times faster). Time lag factor/enhancement ratio (TLF/ER) data confirmed that iontophoresis significantly enhanced permeation. The diffusion coefficients (D, passive) for dextrans were significantly higher than for parvalbumin, with the converse obtained for solubility (C0); permeability coefficients (P) were similar for all three species. Potential differences (V) for the two higher kDa species were significantly higher than for the lowest kDa species. Experimental and theoretical data were in reasonable agreement. SIGNIFICANCE: The experimental and theoretical data, confirming enhanced delivery of the model species via iontophoresis, gave a suitable basis for its potential application in the mouth, in a clinical setting and opens pathways to further research for delivering precious drugs topically and systemically.

Delivery of macromolecules across oral mucosa from polymeric hydrogels is enhanced by electrophoresis (iontophoresis).

OBJECTIVE: To develop polymeric hydrogel delivery systems for iontophorseis transfer of large molecules across buccal (porcine) mucosa. METHODS: Three hydrogels (PVA, HPMC and PVA/HPMC) were prepared as stable gels (7 mm diameter/1.5 mm thick). Quantitative (8 and 36 h) assessment of porcine buccal mucosa and the three hydrogel delivery systems, using a diffusion cell in vitro model, was carried out by UV/vis spectroscopy with three model agents (3 and 10 kDa dextrans and 12 kDa parvalbumin). Passive and iontophoresis parameters were obtained. Experimental and theoretical data were compared. RESULTS: Iontophoresis (30 min, 1-8 h) significantly enhanced the delivery of all model agents across four single systems (hydrogels and buccal mucosa) and three sandwich systems (hydrogels on top of buccal mucosa), as confirmed by time lag factor/enhancement ratio (TLF/ER) data. The diffusion coefficients of model agents across buccal mucosa (×10(-13) m(2) s(-1)) were ~100 times lower than across single hydrogels (2.97-4.80×10(-11) m(2) s(-1)). Solubility values of all agents across hydrogels were similar, but lower across buccal mucosa. Permeability of parvalbumin was highest across PVA, and for both dextrans across PVA/HPMC. In sandwich systems TLFs were similar for all hydrogels, but significantly lower, and ERs significantly higher, than tissue alone. Experimental and theoretical TLF data were in reasonable agreement. SIGNIFICANCE: The in vitro data show that iontophoresis enhanced the delivery of large molecules across polymeric hydrogel systems and buccal mucosa. This creates the opportunity of new approaches to drug delivery and opens pathways to further research for delivering therapeutic agents topically and systemically.