Characterization of the ligand binding of PGRP-L in half-smooth tongue sole (Cynoglossus semilaevis) by molecular dynamics and free energy calculation

Background: Peptidoglycan (PGN) recognition proteins (PGRPs) are important pattern recognition receptors of the host innate immune system that are involved in the immune defense against bacterial pathogens. PGRPs have been characterized in several fish species. The PGN-binding ability is important for the function of PGRPs. However, the PGRP-PGN interaction mechanism in fish remains unclear. In the present study, the 3-D model of a long PGRP of half-smooth tongue sole (Cynoglossus semilaevis) (csPGRP-L), a marine teleost with great economic value, was constructed through the comparative modeling method, and the key amino acids involved in the interaction with Lys-type PGNs and Dap-type PGNs were analyzed by molecular dynamics and molecular docking methods. Results: csPGRP-L possessed a typical PGRP structure, consisting of five ß-sheets and four α-helices. Molecular docking showed that the van der Waals forces had a slightly larger contribution than Coulombic interaction in the csPGRP-L-PGN complex. Moreover, the binding energies of csPGRP-L-PGNs computed by MM-PBSA method revealed that csPGRP-L might selectively bind both types of MTP-PGNs and MPP-PGNs. In addition, the binding energy of each residue of csPGRP-L was also calculated, revealing that the residues involved in the interaction with Lys-type PGNs were different from that with Dap-type PGNs. Conclusions: The 3-D structure of csPGRP-L possessed typical PGRP structure and might selectively bind both types of MTP- and MPP-PGNs, which provided useful insights to understanding the functions of fish PGRPs.

Reduction of immunity in HIV-infected individuals: can fibrosis induce hypoplasia in palatine and lingual tonsils of individuals with HIV infection?

The role of tonsils in oral immunity has been described. However, the pathogenesis of HIV infection in these organs is still unclear. The aim of this study is to perform histological and immunohistochemical analysis of the palatine and lingual tonsils of autopsied individuals with or without HIV infection. Twenty-six autopsied individuals with HIV infection (HI) (n=13) and without HIV infection (CO) (n=13) were selected. Palatine and lingual tonsil fragments were collected for histological and immunohistochemical analysis. We found in the HI group a higher frequency of hyaline degeneration in both palatine and lingual tonsils; smaller follicle areas, and a higher percentage of collagen in comparison with the CO group. In the HI group, there was higher density of blood vessels in palatine tonsils than in the CO group. In the HI group, there were significant positive correlations between palatine and lingual tonsils and the area of lymphoid follicles, and between the percentage of blood vessels and collagen in palatine tonsils. In addition, there was a significant negative correlation between the percentage of collagen and lymphoid follicle area in both palatine and lingual tonsils in the HI group. These findings suggest that the immune functions of these tonsils are prejudiced by fibrosis. Therapies to reduce the neoformation of collagen are required to improve immune function of organs against pathogens.

Preparation of polyclonal antibody against porcine beta defensin 2 and identification of its distribution in tissues of pig.

Porcine ß-defensin 2 (pBD2) is an antimicrobial peptide in pigs that plays an important role in the immune system by preventing bacterial invasion. To produce an anti-pBD2 antibody, which is not commercially available, we expressed and purified a soluble, his-tagged version of pBD2 (his-pBD2). Purified pBD2 was injected into New Zealand white rabbits to generate polyclonal antiserum. Anti-pBD2 antibodies were purified by ammonium sulfate precipitation, followed by diethylaminoethyl cellulose ion-exchange chromatography. The purified polyclonal antibody showed high sensitivity, with a titer as high as 204,800 by enzyme-linked immunosorbent assay, and it also showed high specificity for both his-pBD2 and native pBD2, as assessed by western blotting. Furthermore, immunohistochemistry analysis using the purified antibody revealed that pBD2 protein is distributed in the tongue, liver, kidney, small intestine, and large intestine of pigs. These results indicate that the prepared polyclonal antibody will be a useful tool for further studies of the function and mechanism of pBD2.

Inflammation and glandular duct dilatation of the tongue from patients with chronic Chagas disease.

The purpose of this study was to evaluate morphologically the tongue of individuals with chronic Chagas disease (CD) in comparison to the non-chagasic ones. Twenty-four protocol cases of autopsies were selected. They were subdivided into CD patients (10 cases) and non-chagasic ones (14 cases). The morphometric analysis was accomplished for the tongue muscle and salivary glands duct lumen area. In three CD patients, perineuritis was found, and two of them showed megaesophagus and megacolon. The intensity of the inflammation in the von Ebner's glands, the tongue muscles, and the salivary glands duct lumen area was significantly higher in the CD patients. We concluded that the CD patients show salivary glands duct dilatation, which probably would have a relation with alterations in the autonomic nervous system. The inflammation found in CD patients is in accordance with that described in comparative studies on the digestive tract and heart. These morphological findings suggest that the histopathological analysis of the tongue associated with other organs, or even in an isolated manner, can add in the diagnosis and pathogenesis of the CD chronic phase.

Matrilisinas e B-catenina em carcinoma de células escamosas de língua - relação com o potencial metastático tumoral / Matrilisinas and B-catenina in carcinoma of escamos cells of language - relation with the tumoral metastatico potential

O carcinoma de células escamosas (CCE figura entre aslesões de maior interesse da região bucal e quando presente em língua exibe aspecto mais infiltrativo, curso clínico agressivo e prognóstico desfavorável, o que pode estar associado com maior potencial metastático. O presente trabalho investigou a expressão da B-catenina, metaloproteinase-7 (MMP-7) e da 26 (MMP-26) em CCE de língua e divididos em dois grupos: grupo metástico (n=12) e grupo sem metástase (n=12) os quais foram submetidos a marcação imunohistoquímica. Realizou-se uma análise semi-quantitativa no fronte invasivo tumoral e a imunoexpressão das proteínas foi categorizada como sendo negativa, positiva e fortemente positiva, atribuindo-se escores, 0 + e ++, respectivamente. A expressão para B-catenina demonstrou que 33 por cento dos casos foram escore "0", 50 por cento escore "+" e 17 por cento escore "++" no grupo metastatico; 42 por cento com escore "0", 33 por cento escore "+" e 25 por cento escore "++" no grupo sem metástase. Alem disso, a B-catenina demonstrou marcação ora restrita à membrana ora citoplasmática ou nuclear e, ainda, associação destas. Com relação à MMP-7, os resultados demonstraram padrão de marcaço idêntico nos dois grupos, onde 17 por cento dos casos exibiram escore "0, 50 por cento "+" e 33 por cento "++". Tratando-se de MMP-26, observaram-se 25 por cento com escore "0", 8 por cento "+" e 67 por cento escore "++" no grupo metatástico; 8 por cento com escore "0", 50 por cento "+" e 42 por cento escore "++" no grupo sem metástase. A análise estatística através dos testes U de Mann e Whitney e correlação de Spearmam não demonstrou nunhuma diferença significativa entre a expressão das proteínas nos dois grupos e, tampouco, correlação entre a expressão das mesmas. Diante destes dados, conclui-se que a expressão da B-catenina, MMP-7 e MMP-26 não constitui um método eficaz isolado para predizer o potencial metastatico dos CCE em língua

Mast cell Fc epsilonRI expression in the rat intestinal mucosa and tongue is enhanced during Nippostrongylus brasiliensis infection and can be up-regulated by in vivo administration of IgE.

The activation of rodent and human mast cells can occur through the cross-linking of tetrameric IgE receptors each containing single alpha- and beta- and two gamma-subunits. However, the factors that regulate the in vivo expression of Fc epsilonRI are poorly understood. We have examined the expression of the Fc epsilonRI beta-subunit in the Nippostrongylus brasiliensis (Nb)-induced mode l of rat intestinal inflammation. We developed a double-staining technique for mast cell granules (Alcian blue) and the beta-subunit of Fc epsilonRI. The intensity of immunohistochemical staining per mast cell was quantified using an image analysis system. Jejunal and tongue mast cells of Lewis rats were visible by Alcian blue staining before Nb infection, but they expressed very low levels of beta-subunit as assessed by immunohistochemical staining. These levels were increased by day 11 postinfection and reached a maximum at day 14. Since serum IgE levels correlated well with the degree of beta-subunit expression, we investigated whether the observed enhancement of receptor expression might occur through the stabilization of receptor complexes by IgE. Therefore, Lewis rats were treated with myeloma IgE, and beta-subunit expression was examined. In both tongue and jejunal tissue, a significant rise in beta-subunit expression was observed in response to IgE injection, although levels of beta-subunit expression were not as high as those observed in Nb-infected animals. The increase in beta-subunit expression was accompanied by an increase in the amount of mast cell-associated IgE. These observations may have important implications for the regulation of IgE receptor expression during disease.

Organ-specific circulating heart autoantibodies in Chagas' cardiomyopathy: exploratory study.

Chagas' disease can evolve to a chronic phase with cardiomyopathy that may include autoimmune mechanisms, among others. Recently an organ-specific anti-heart muscle antibody was detected in idiopathic cardiomyopathy, using human heart muscle as antigen. We decide to standardize an indirect immunofluorescence assay using rat organs in order to evaluate frequency of organ-specific anti-heart antibodies in chagasic cardiomyopathy. We tested 18 patients with chagasic cardiomyopathy for serum organ-specific anti-heart muscle antibodies. Nine patients were positive for organ-specific anti-heart antibodies (positive in heart muscle but negative in tongue muscle) and one was positive for non-organ-specific anti-heart muscle antibodies (positive in both heart and tongue muscle). We conclude that organ-specific anti-heart muscle antibodies can be detected using rat organs as antigens. Organ-specific anti-heart muscle antibodies are present in patients with chagasic cardiomyopathy.