Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/7/2009
Publication Date: 7/15/2009
Citation: Li, R.W., Li, C., Elsasser, T.H., Liu, G., Garrett, W.M., Gasbarre, L.C. 2009. Mucin biosynthesis in the bovine goblet cell induced by Cooperia oncophora infection. Veterinary Parasitology. PMID 19647371.
Interpretive Summary: Forty one different species of nematodes have been described as parasites in the gastrointestinal tract in cattle. These parasites are the cause of considerable economical loss to the American cattle industry. Parasitic nematode infection elicits drastic changes in gene expression patterns in host cells. In this study, we examined cell-specific expression of seven mucins and seven enzymes involved in O-linked glycosylation in mucin biosynthesis at mRNA levels using laser capture microdissection (LCM). Some of our results were further verified by Western blot analysis and immunohistochemistry. Our results provided insight into the roles that mucins play in protective immunity against nematode infection in the bovine gastrointestinal tract.
Technical Abstract: Mucin hypersecretion is considered to be one of the most common components of the immune response to gastrointestinal nematode infection. However, investigations have not been conducted in the Cattle-Cooperia oncophora system to verify the findings largely derived from murine models. In this study, we examined the expression of 7 mucins and 7 enzymes in the mucin biosynthesis pathway involved in O-linked glycosylation in the bovine small intestine including goblet cells that were enriched using laser capture microdissection during Cooperia oncophora infection. At the mRNA level, MUC 2 expression was significantly higher in both lamina propria and goblet cells at 28 days post infection (dpi) compared to the naïve control. MUC5B expression at the mRNA level was also higher in lamina propria at 28dpi. Expression of MUC1, MUC4, MUC5AC, and MUC6 was extremely low or not detectable in goblet cells, columnar epithelial cells, and lamina propria from both naïve control and infected animals. Among the 7 enzymes involved in post-translational O-link glycosylation of mucins, GCNT3, which may represent one of the key rate-limiting steps in mucin biosynthesis, was up-regulated in goblet cells, columnar epithelial cells, lamina propria, and gross small intestine tissue during the course of infection. Western blot analysis revealed that MUC2 glycoprotein was strongly induced by infection in both gross small intestine tissue and its mucosal layer. In contrast, the higher MUC5B protein expression was observed only in the mucosal layer. Immunohistochemistry provided further evidence of the mucin glycoprotein production and localization. Our results provided insight into regulation of mucin biosynthesis in various cell types in the bovine small intestine during gastrointestinal nematode infection and will facilitate our understanding of mucins and their role in immune response against parasitic nematodes.