East Tennessee State University
Southern, Timothy Robert.
Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro.
Degree: PhD, Biomedical Sciences, 2007, East Tennessee State University
Microsporidia are obligate intracellular pathogens that cause severe disease in immunocompromised humans. While albendazole is the treatment of choice, no therapy exists that effectively treats all forms or causes of human microsporidiosis. Recent studies show that the microsporidian Encephalitozoon intestinalis binds glycosaminoglycans (GAGs) associated with the host cell surface, and that the divalent cations manganese (Mn2+) and magnesium (Mg2+) augment spore adherence to host cells by activating a constituent on the spore surface. These studies also illustrate a direct relationship between spore adherence and host cell infection; inhibition of spore adherence leads to reduced host cell infection while augmentation of spore adherence increases host cell infection. In light of recent studies, microsporidia spore adherence has become a promising target for the development of novel therapeutics to treat or even prevent human microsporidiosis. The goal of this study was to further characterize the molecular mechanisms governing spore adherence by identifying specific constituents on microsporidia spores that participate in spore adherence with host cells. A 40 kDa Encephalitozoon cuniculi host cell binding protein was discovered and identified as ECU01_0820, hereafter known as Encephalitozoon cuniculi microsporidia spore adherence protein (EcMsAP). The gene encoding EcMsAP has multiple heparin-binding motifs and an integrin-binding domain, which are characteristic of proteins that interact with constituents on the cell surface. Immuno-transmission electron microscopy reveals that native EcMsAP is located on the plasma membrane, endospore, exospore, and the anchoring disk of microsporidia spores. Recombinant EcMsAP and antibodies to recombinant EcMsAP both inhibit spore adherence and host cell infection. However, the deletion of heparin-binding motif1 from the EcMsAP gene results in the loss of ability to inhibit spore adherence and infection. Host cell-binding assays reveal that recombinant EcMsAP binds Vero and CHO cell lines, but exhibits attenuated binding to glycan-deficient CHO cell lines. Finally, biomolecular interactions analysis provides direct evidence that EcMsAP is a glycan binding protein. This study not only identifies a potential microsporidial vaccine candidate, it further supports the assertion that microsporidia spore adherence is a critical step in the host cell infection process.
Subjects/Keywords: MsAP; Microsporidia Attachment Protein; Infectivity; Adherence; Encephalitozoon cuniculi; Encephalitozoon intestinalis; Microsporidia; Biochemistry, Biophysics, and Structural Biology; Life Sciences; Molecular Biology
to Zotero / EndNote / Reference
APA (6th Edition):
Southern, T. R. (2007). Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro. (Doctoral Dissertation). East Tennessee State University. Retrieved from https://dc.etsu.edu/etd/2081
Chicago Manual of Style (16th Edition):
Southern, Timothy Robert. “Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro.” 2007. Doctoral Dissertation, East Tennessee State University. Accessed May 10, 2021.
MLA Handbook (7th Edition):
Southern, Timothy Robert. “Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro.” 2007. Web. 10 May 2021.
Southern TR. Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro. [Internet] [Doctoral dissertation]. East Tennessee State University; 2007. [cited 2021 May 10].
Available from: https://dc.etsu.edu/etd/2081.
Council of Science Editors:
Southern TR. Examination of Microsporidia Spore Adherence and Host Cell Infection In Vitro. [Doctoral Dissertation]. East Tennessee State University; 2007. Available from: https://dc.etsu.edu/etd/2081