Sara Ahlgren, PhD Assistant Professor Pediatrics, CMRC Craniofacial growth and development Curricula: Developmental Biology Molecular Biology and Genetics E-mail:   s-ahlgren@northwestern.edu

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My lab studies the processes that regulate the early development of the embryo, including cell movements, survival, proliferation, and differentiation.  We focus on a number of proteins which are linked to human birth defects, to try to understand these abnormalities.  In order to observe changes in cells and gene expression, we model human birth defects in both chicken and zebrafish embryos.  This combination of systems allows us to have rapid interrogation of developing embryos as well as large supplies of tissues for comparative studies.  We focus on the Sonic Hedgehog signaling pathway, which plays multiple roles in establishing cell fates, as well as regulating cell numbers by controlling both proliferation and survival.

Current studies in my lab include exploring the gene expression changes produced by embryonic exposure to ethanol, and developing novel therapeutics that can restore normal development without causing harm to non-affected embryos.  We are also studying the role that Shh signaling plays in ethanol-induced abnormalities.

Human patients with loss of one copy of SHH have a birth defect known as holoprosencephaly, which is a failure of the forebrain to split into two halves. While primarily diagnosed as a brain abnormality, patients with holoprosencephaly typically have abnormal craniofacial features as well, suggesting a link between brain and face development.  While a complete loss of Sonic hedgehog signaling results in an embryo with almost no craniofacial features, we use a less severe mutant which retains 40% of normal levels of shh signaling to understand, in context, the role that this pathway plays in regulating normal development.  Part of this project also involves creating novel transgenic lines of zebrafish to better track individual cells and regions of gene expression during normal and abnormal development.

Selected Publications:

Loucks, E.J., Ahlgren S.C. (2009) Deciphering the role of Shh signaling in axial defects produced by ethanol exposure.  Birth Defects Research A: Clinical and Molecular Teratology 85:556-67.

Ahlgren, S. (2008) Cell division, differentiation, and death in avian embryos.  Methods in Cell Biology, 87:153-65.

Loucks, E.J., Schwend, T., Ahlgren, S.C. (2007) Molecular changes associated with teratogen-induced cyclopia.  Birth Defects Research A: Clinical and Molecular Teratology, 79(9):642-51

S.C. Ahlgren, P.K. Vogt and M. Bronner-Fraser (2003) Excess FoxG1 causes overgrowth of the neural tube. Journal of Neurobiology 57:337-349.

S.C. Ahlgren, V. Thakur, and M. Bronner-Fraser (2002) Sonic hedgehog rescues neural crest from cell death induced by ethanol exposure. Proceedings of the National Academy of Sciences, U.S.A. 99:10476-10481.

S.C. Ahlgren and M. Bronner-Fraser (1999) Inhibition of Sonic hedgehog signaling in vivo results in craniofacial neural crest cell death. Current Biology 9:1304-1314.

View Publications by Sara Ahlgren listed in the National Library of Medicine (PubMed).