This F32 postdoctoral award includes a three year plan of mentoring, courses and research that will facilitate my growth to become an independent clinician-scientist and be eligible for moving into an assistant professor position. My primary interest is in decreasing the number of children born with cleft lip/cleft palate (CLP), the most common craniofacial birth defect (1/750 live births). Although it is well known that maternal cigarette smoking is a risk factor for facial cleft defects, the underlying mechanism and genes involved have been not identified. The central hypothesis of this application is that maternal and fetal genetic background influences growth and development genes and in some individuals nicotine disturbs the Tgf23 pathway essential for palatal development. The long term goal of this project is to detect genes that are influenced by nicotine and may affect palate development. Also, we will determine the potential effect of counteracting nicotine effects with antioxidants such as ferulic acid. The following two aims are proposed:
Aim 1 : Determine whether ferulic acid can alter the genetic changes caused by nicotine exposure to prevent the development of a cleft palate. Previous studies determine that ND4 mice are more resistant to nicotine than C57B6J mice. Pregnant mice will be exposed to nicotine through an osmotic pump. RNA from fetal palate tissues will be analyzed by a microarray for specific genes involved in development and palatal fusion. Ferulic acid will be included in the diet of pregnant mice to determine if its protective effect can prevent cleft palate.
Aim 2 : Establish whether nicotine interferes with palatal shelf fusion by down regulating Tgf23 signals and determine if ferulic acid can counteract those effects. Previous experiments demonstrated that nicotine inhibited palatal fusion in vitro in a dose dependent manner. We have also shown that Tgf23 is an essential growth factor during palate fusion. This growth factor stimulates the expression of the transcription factors: Twist1 and Snail1. We will compare nicotine treated palates to untreated palates to determine if the susceptible animals down regulate the signaling pathways or transcription factors essential for palate closure. Also we will determine if ferulic acid can counteract the effect of nicotine by changing the levels of important signaling molecules. The proposed work is significant because it will provide translational data for future human studies. The results will provide evidence of genes that are influenced by nicotine and will also identify the signal transduction pathways that can be targeted for intervention and supplements that may counteract the nicotine effects on fetal development and birth defects. In addition, the results from this study would address one of the main goals of NIDCR in the public health area, which is the prevention of craniofacial defects.
Relevance of this research to public health. (mission of the agency) We have known for years that smoking has a deleterious effect on fetal growth and craniofacial development. However, we do not know which genes make some individuals more susceptible than another. We have identified an animal model that also shows variability in response to nicotine and will use it to identify candidate genes that promote resistance to nicotine. In addition, we will determine if a dietary supplement as ferulic acid can counteract the effects of nicotine in palatal fusion.
