title: Mucin-type O-glycosylation in Mesocestoides vogae (syn. corti).
abstract: Protein glycosylation is an important post-translational modification underlying host-parasite interactions, which may determine the outcome of infection. Although Mesocestoides vogae represents an important model for investigating the various aspects of cestode biology, virtually no information is available about the structure and synthesis of glycans in this parasite. In this work, focused on the initiation pathway of mucin-type O-glycosylation in M. vogae, we characterized O-glycoproteins bearing the simple mucin-type cancer-associated Tn and sialyl-Tn antigens, and the expression and activity of ppGalNAc-T, the key enzyme responsible for the first step of mucin-type O-glycosylation. Using immunohistochemistry, Tn and sialyl-Tn antigens were detected mainly in the tegument (microtriches) and in parenchymal cells. Tn expression was also observed in lateral nerve cords. Both Tn and sialyl-Tn antigens were detected in in vitro cultured parasites. Based on their electrophoretic mobility, Tn- and sialyl-Tn-bearing glycoproteins from M. vogae were separated into several components of 22 to 60 kDa. The observation that Tn and sialyl-Tn glycoproteins remained in the 0.6N perchloric acid-soluble fraction suggested that they could be good candidates for characterizing mucin-type glycosylation in this parasite. O-glycoproteins were purified and initially characterized using a proteomic approach. Immunohistochemical analysis of the tissue distribution of ppGalNAc-T revealed that this enzyme is expressed in the sub-tegumental region and in the parenchyma of the parasite. In M. vogae cultured in vitro, ppGalNAc-T was mainly detected in the suckers. Using a panel of 8 acceptor substrate synthetic peptides, we found that M. vogae ppGalNAc-T preferentially glycosylate threonine residues, the best substrates being peptides derived from human mucin MUC1 and from Trypanosoma cruzi mucin. These results suggest that M. vogae might represent a useful model to study O-glycosylation, and provide new research avenues for future studies on the glycopathobiology of helminth parasites.
authors: Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
authors: Andrea
authors: A
authors: Medeiros
authors: María Laura
authors: ML
authors: Chiribao
authors: Luis
authors: L
authors: Ubillos
authors: María Florencia
authors: MF
authors: Festari
authors: Jenny
authors: J
authors: Saldaña
authors: Carlos
authors: C
authors: Robello
authors: Laura
authors: L
authors: Domínguez
authors: Juan José
authors: JJ
authors: Calvete
authors: Eduardo
authors: E
authors: Osinaga
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000032:analysis / Q000378:metabolism*; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000378:metabolism; D015153:Blotting, Western; D002240:Carbohydrate Sequence; D002590:Cestode Infections / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006790:Host-Parasite Interactions; D007150:Immunohistochemistry; D008645:Mesocestoides / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D009077:Mucins / Q000378:metabolism; D017350:N-Acetylgalactosaminyltransferases / Q000032:analysis; D010274:Parasitology / Q000379:methods; D000097763:Polypeptide N-acetylgalactosaminyltransferase
chemical_list: D000947:Antigens, Helminth; D015295:Antigens, Tumor-Associated, Carbohydrate; D009077:Mucins; D017350:N-Acetylgalactosaminyltransferases; D000097763:Polypeptide N-acetylgalactosaminyltransferase; C040286:Tn antigen; C055491:sialosyl-Tn antigen