Diabetic embryopathy is a well recognized, but poorly understood, complication of diabetes in which the early embryo of a diabetic method develops congenital malformations. The objective of the work proposed here is to study the regulation by diabetes of a critical development control gene, Pax-3, during the development of one of the most common diabetes- associated malformations, neural tube defects (NTD). Using a new mouse model that was developed in my laboratory, we have observed that the rate of NTD is about three-fold higher in the embryos of diabetic mice than in the embryos of non-diabetic mice. The high rate of NTD is correlated with reduced expression of Pax-3, an embryonic gene which encodes a DNA-binding transcription factor that is required for formation of the brain and spinal chord. Subsequent to the reduction in expression of Pax-3, and apparently as a consequence, cells forming the neural tube are seen to undergo unscheduled apoptosis. There are three specific aims of this proposal. In the first aim, we will test the hypothesis that glucose toxicity associated with maternal diabetes is responsible for abnormalities in embryonic gene expression, apoptosis, and NTD. This will be accomplished by (1) attempting to prevent glucose toxicity by lowering glucose levels in pregnant diabetic mice with insulin or phlorizin administration, (2) attempting to induce glucose toxicity in pregnant non-diabetic mice by a hyperglycemic glucose clamp procedure, (3) attempting to induce glucose toxicity during culture of post-implementation mouse embryos in media containing elevated levels of glucose, and (4) testing whether expression of the high Km GLUT-2 glucose transporter renders the early embryos sensitive to glucose toxicity during diabetic pregnancy. In the second aim, we will determine whether the reduction in Pax-3 mRNA observed in embryos of diabetic and non-diabetic mice is due to transcriptional or post-transcriptional control, and identify the Pax-3 control elements involved in inhibition by diabetes. In the third aim, we will test the hypothesis that mouse strains which fail to develop NTD during diabetic pregnancy are resistant to the inhibition of Pax-3 expression that occurs in strains which are susceptible to NTD. These experiments will reveal, in a way that has not been done in the past, the molecular mechanisms by which embryonic development is during diabetic pregnancy.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
1R01DK052865-01A1
Application #
2620475
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Program Officer
Linder, Barbara
Project Start
1998-08-01
Project End
2003-07-31
Budget Start
1998-08-01
Budget End
1999-07-31
Support Year
1
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Joslin Diabetes Center
Department
Type
DUNS #
071723084
City
Boston
State
MA
Country
United States
Zip Code
02215
Jung, Jin Hyuk; Iwabuchi, Kumiko; Yang, Zhihong et al. (2016) Embryonic Stem Cell Proliferation Stimulated By Altered Anabolic Metabolism From Glucose Transporter 2-Transported Glucosamine. Sci Rep 6:28452
Loeken, Mary R (2014) Intersection of complex genetic traits affecting maternal metabolism, fetal metabolism, and neural tube defect risk: looking for needles in multiple haystacks. Mol Genet Metab 111:415-7
Sanders, Kaitlyn; Jung, Jin Hyuk; Loeken, Mary R (2014) Use of a murine embryonic stem cell line that is sensitive to high glucose environment to model neural tube development in diabetic pregnancy. Birth Defects Res A Clin Mol Teratol 100:584-91
Jung, Jin Hyuk; Wang, Xiao Dan; Loeken, Mary R (2013) Mouse embryonic stem cells established in physiological-glucose media express the high KM Glut2 glucose transporter expressed by normal embryos. Stem Cells Transl Med 2:929-34
Loeken, Mary R (2012) A new role for pancreatic insulin in the male reproductive axis. Diabetes 61:1667-8
Wang, Xiao Dan; Morgan, Sarah C; Loeken, Mary R (2011) Pax3 stimulates p53 ubiquitination and degradation independent of transcription. PLoS One 6:e29379
Zabihi, Sheller; Loeken, Mary R (2010) Understanding diabetic teratogenesis: where are we now and where are we going? Birth Defects Res A Clin Mol Teratol 88:779-90
Chappell Jr, James H; Wang, Xiao Dan; Loeken, Mary R (2009) Diabetes and apoptosis: neural crest cells and neural tube. Apoptosis 14:1472-83
Morgan, Sarah C; Lee, Hyung-Yul; Relaix, Frederic et al. (2008) Cardiac outflow tract septation failure in Pax3-deficient embryos is due to p53-dependent regulation of migrating cardiac neural crest. Mech Dev 125:757-67
Morgan, Sarah C; Relaix, Frederic; Sandell, Lisa L et al. (2008) Oxidative stress during diabetic pregnancy disrupts cardiac neural crest migration and causes outflow tract defects. Birth Defects Res A Clin Mol Teratol 82:453-63

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