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Virus-Host Interactions at the Maternal-Fetal Interface

Delorme-Axford, Elizabeth (2013) Virus-Host Interactions at the Maternal-Fetal Interface. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Strategies to protect against viral infections are essential during pregnancy. Maternal-fetal transmission can have serious pathological outcomes, including fetal infection, growth restriction, birth defects, and/or death. Throughout pregnancy, the placenta (composed of polarized trophoblasts amid stromal and vascular arrangements) is an indispensable tissue that forms a barrier at the maternal-fetal interface. Viruses have likely evolved specific mechanisms to exploit the protective functions of placental trophoblasts to initiate fetal infection. Despite the severity of pathologic disease associated with fetal viral infection, little is known regarding virus-host interactions at the maternal-fetal interface. In this work, we have examined the mechanisms by which – 1) placental trophoblasts protect against invading viruses and 2) coxsackievirus B (CVB), a virus associated with fetal pathology, gains entry into polarized trophoblasts. As a model, we have used cultured primary human trophoblasts (PHTs) and immortalized human (BeWo) trophoblasts.

We have found that PHTs are highly resistant to infection by six disparate viruses. PHTs transfer this resistance to non-placental recipient cells through exosome-mediated delivery of select placental microRNAs (miRNAs). We show that members of the chromosome 19 miRNA cluster (C19MC), which are almost exclusively expressed in the primate placenta, are packaged within trophoblast-derived exosomes, and attenuate viral replication in recipient cells by inducing autophagy.

To study CVB entry into placental trophoblasts, we have merged virological and cell biological techniques, combined with pharmacological inhibitors and siRNAs directed against diverse cellular endocytic and signaling components, to characterize the pathways hijacked by CVB to promote its entry into human trophoblasts. We found the kinetics of CVB entry and uncoating in placental trophoblasts similar to those described in polarized intestinal epithelial cells. CVB entry into placental trophoblasts requires decay accelerating factor (DAF) binding, and is associated with the relocalization of virus from the apical surface to intercellular tight junctions. We have identified a divergent mechanism for CVB entry that is independent of clathrin, caveolae, and dynamin II but is dependent on lipid-rafts and Src family tyrosine kinase signaling. Our studies model viral transmission and infection at the maternal-fetal interface, and have the therapeutic potential for preventing prenatal infections, pre-term labor, and birth defects.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Delorme-Axford, Elizabethebd7@pitt.eduEBD7
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Thesis AdvisorCoyne , COYNEC2
Committee ChairWeisz, Ora Aweisz@pitt.eduWEISZ
Committee MemberSadovsky , Yoel ysadovsky@mwri.magee.eduYOS14
Committee MemberCondon-Jeyasuria , Jennnifer
Date: 2 April 2013
Date Type: Publication
Defense Date: 14 March 2013
Approval Date: 2 April 2013
Submission Date: 1 April 2013
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 157
Institution: University of Pittsburgh
Schools and Programs: School of Medicine > Cell Biology and Molecular Physiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Placenta, Trophoblast, C19MC, Autophagy, Coxsackievirus B, miRNAs
Date Deposited: 02 Apr 2013 15:02
Last Modified: 19 Dec 2016 14:40


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