M.S. - Developmental and Reproductive Biology
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ItemExocyst Dysfunction Impairs Urothelial Development Resulting in Congenital Ureter Obstruction([Honolulu] : [University of Hawaii at Manoa], [August 2016], 2016-08)Hydronephrosis is the most commonly detected abnormality in prenatal ultrasounds. The most Prevalent cause of prenatal hydronephrosis is congenital obstructive nephropathy, with obstructions at the ureteropelvic junction (UPJ) region as the most common site for obstruction. The cause and developmental process of obstruction formation at the UPJ is poorly understood. We developed a Sec10 conditional knockout (Sec10-CKO) mouse model where Sec10, a critical subunit of the exocyst complex, has been knocked out in the urothelium that lines the ureter. Sec10-CKO embryos develop complete bilateral UPJ obstructions and hydronephrosis by day 18.5 of gestation (E18.5). Using this model, we were able to study the development of prenatal hydronephrosis. We determined that the urothelium lining the ureters of Sec10-CKO mice fails to differentiate, with the earliest evidence of this starting at E16.5. Loss of key terminal differentiation markers, including uroplakins, weakens the urothelial barrier that prevents urine from permeating into ureter tissues. Our data suggests that a luminal wound healing response at the UPJ starts at E17.5, which would correspond with the time point urine first starts to flow. We measured three characteristics consistent with a fibrotic wound healing response: (1) increased expression of TGFβ1, a key regulator of wound healing and fibrosis, (2) gene expression profiles consistent with myofibroblast activation, with increased proliferation at the site of obstruction, and (3) evidence of stromal remodeling. Our findings support a model where prenatal UPJ obstructions may be caused by an impaired urothelial barrier that allows urine to permeate and damage tissues lining the lumen, inducing a fibrotic wound healing response.
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ItemCell Survival Characterization of Human Amnion Mesenchymal Cells Grown in Novel 3D Culture System and Gene Expression Comparison to 2D Culture([Honolulu] : [University of Hawaii at Manoa], [August 2015], 2015-08)
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ItemThe Teratogenic Effects of Anti-Diabetic Drugs: In Vitro Assays Using Embryoid Body Morphogenesis([Honolulu] : [University of Hawaii at Manoa], [May 2015], 2015-05)Many adults take some form of medication to treat chronic conditions, however little is known about their effects on embryogenesis and pregnancy. With the increase in fertility problems society is facing and the increase in use of medications, it is important to understand what effects pharmaceuticals have on the developing embryo to ensure that future generations are not adversely affected by teratogenic compounds that can lead to birth defects. In this study, teratogenicity of anti-diabetic compounds was examined using the in vitro P19C5 embryoid body (EB) elongation morphogenesis model. As the EB model recapitulates key embryological events crucial for body patterning and axis formation, adverse impact of drugs on EB growth and elongation implicates their potential teratogenicity. Of the 31 anti-diabetic compounds examined, 27 decreased EB size and 11 either decreased or increased EB elongation at a given concentration. Morphogenetic impact of four specific anti-diabetic drugs, dapagliflozin, phenformin HCl, manidipine 2HCl, and resveratrol, was further examined by investigating expression patterns of key developmental regulators. Each drug exhibited a unique effect on gene expression patterns. Notably, dapagliflozin significantly reduced the level of the Wnt3 gene, a crucial regulator of the primitive streak formation. The Wnt-inhibiting effect of dapagliflozin was also confirmed by the TOPFLASH reporter assay. Furthermore, it was revealed that the drug impact on EB size was likely mediated by adverse effect on cell proliferation. These results suggest that anti-diabetic compounds impact EB morphogenesis by perturbing key developmental regulators, cellular signaling, and proliferation. The present research should lay the foundation for further investigations, including animal and human studies, to determine teratogenicity of specific anti-diabetes medications.