Establishment and characterization of day 30 equine chorionic girdle and allantochorion cell lines

Salman, Saleh M., author
Bruemmer, Jason E., advisor
Bouma, Gerrit, advisor
Magee, Christianne, committee member
Pinedo, Pablo, committee member
Winger, Quinton, committee member
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Establishing cell lines is a good model for experimental applications to study molecular mechanisms and cell-specific gene expression. A human resistant telomerase reverse transcriptase (hTERT) lentivirus was utilized to establish stable equine embryonic cell lines. Equids have a diffuse epitheliochorial placenta, where the invasive trophoblast is represented by the chorionic girdle (CG) and the noninvasive trophoblast are the allantochorion (AC). Embryonic CG cells are unique to horses compared to other farm animals' embryos. The CG cells are the predecessor of endometrial cups (EC) that differentiate, proliferate, and invade the endometrium by day 38 of pregnancy, yet morphologically, both have similar characteristics supporting the fetal origin for EC. The CG cells have a crucial role in equine chorionic gonadotropin (eCG) production and maintenance of pregnancy during the first trimester. This study has three objectives: 1) establishing a stable cell line from day 30 CG cells and AC using lentivirus encoding hTERT; 2) Characterization of day 30 CG cells and AC cell morphology and expression of eCG alpha (eCGα) and beta (eCGβ) subunits, major histocompatibility complex class II (MHC II), and Kisspeptin receptor (KISS1R) in CG and AC cells; 3) investigating eCG protein production in vitro from day 30 CG and AC cells. Reverse transcriptase (RT) PCR was used to study gene expression in cells and radioimmunoassay (RIA) was used to investigate protein presence in the media. We established a hygromycin-resistant day 30 CG and AC cell lines that express eCGα, eCGβ, and hTERT and confirmed using RT-PCR yielding the predicted bands. The cell lines were maintained for 16 passages, 10 of which were cultured after the lentiviral infection steps. Also, we characterized CG cells as fast-growing, large, binucleated, and epithelioid, and AC cells as rapid-growing showing smaller, squamous, mononucleate, epithelioid, and elongated fibroblastic cells. The RT-PCR results showed eCGα and eCGβ subunits are expressed by both day 30 CG and AC cells, but MHC II and KISS1R genes were not expressed in either of cells. Moreover, RIA results showed that day 30 CG cells did produce eCG protein in vitro earlier than what previous literature has shown. However, day 30 AC cells did not produce eCG protein in vitro, and both CG and AC cell lines stopped secreting eCG in the media after the lentiviral infection.
2019 Spring.
Includes bibliographical references.
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