Untersuchungen zur Bürstenzell-spezifischen Expression des murinen Norovirus, sowie der Rezeptoren CD300LF und Siglec-F im intestinalen und biliären System der Maus
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A number of surface receptors have been identified for tuft cells, a rare type of chemosensory cell. The receptor profile influences which stimuli can activate the tuft cell and to what extent. Components of certain pathogens, including viruses, can also bind to the tuft cell in this way. Activation leads to the secretion of messenger substances into the surrounding tissue and influences immunological processes in the organism via activating or inhibiting processes. Tuft cells therefore play an important role in epithelial immune defense.
Murine norovirus (MNoV), a virus from the norovirus group, is the most common pathogen among laboratory mice and causes persistent infections with highly variable courses. To date, there is no reliable method for identifying virus-excreting mice that is suitable for screening live laboratory animals. Tuft cells have been described as target cells for murine norovirus, with binding occurring via the CD300LF receptor according to current knowledge.
Sialic acid-binding lectin F (Siglec-F), one of the lectins belonging to the immunoglobulin superfamily, is also expressed in tuft cells, but cell-specific detection in different tissues has not yet been performed.
This study aimed to investigate the expression profile of the CD300LF and Siglec-F receptors with regard to tuft cells. Furthermore, we sought to visualize MNoV at the mRNA level in a possible cell-specific distribution in tissue and to investigate the infection status of individual laboratory mice. Using in situ hybridization on different tissues in which tuft cells are present, we examined the mRNA expression of MNoV, the receptor Cd300lf, and Siglecf for possible tuft cell specificity. In addition, immunohistochemical detection at the protein level was performed for CD300LF.
For MNoV, it was found that in situ hybridization was not suitable as a detection method in our experiment and no specific signals could be generated. At the same time, the infection status of individual mice was examined using reverse transcriptase PCR (RT-PCR) with stool and blood samples. The viral RNA sought was detected in many, but not all, of the stool samples examined; there was no evidence of viremia caused by MNoV. This showed that RT-PCR is suitable for virus detection from stool samples, at least as a complementary method for rapid, non-invasive detection of MNoV in order to identify animals that are excreting the virus.
For Cd300lf, mRNA was detected in a cell-specific manner in intestinal and biliary tissue, with co-labeling demonstrating brush cell specificity. Colocalization was also demonstrated in the tongue in the area of the papilla vallata, but not in thymus tissue. Tuft cell specificity was also supported at the protein level by antibody-based immunohistochemistry. Overall, the results suggest that CD300LF is a tuft cell-specific receptor in intestinal and biliary tissues of the mouse and is also present in tissues outside of these areas in a tuft cell-specific manner.
These findings expand our understanding of tuft cells as target cells of MNoV and provide new approaches for characterizing their role in mucosal immune defense.
Clear, cell-limited signals were also observed for Siglecf in in situ hybridization in the mucosa of the examined sections of the intestinal tract and biliary tissue. The signals coexisted in a double labeling with enhanced green fluorescent protein (eGFP), a tuft cell-specific marker. Based on the results, we therefore assume that Siglecf is cell-specific for tuft cells in these tissues. In other tissues examined, namely the tongue with papilla vallata in section and the thymus, no specific signals could be generated with the generated antisense probe against Siglecf, meaning that cell specificity or the presence in tuft cells could not be demonstrated there. Overall, the results on the detection of Siglecf expand our knowledge of the surface profile of tuft cells and thus contribute to a deeper understanding of their immunological functions.
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Issued: 2026-05-04
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FB20:Medizin
Language
de
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Norovirus
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Mahnke, Julia: Untersuchungen zur Bürstenzell-spezifischen Expression des murinen Norovirus, sowie der Rezeptoren CD300LF und Siglec-F im intestinalen und biliären System der Maus. : 2026-05-04. DOI: https://doi.org/10.17192/openumr/682.
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