Role of TGFbeta2 in cardiac neural crest cells

Neural crest cells (NC) are multi-potent cells which originate in the dorsal neural tube and migrate to the mammalian heart during embryonic development. Defective migration of NC results in defects in the outflow tract region of the heart at birth (i.e., congenital heart defects, CHD). In this project, genetically engineered mice embryos with selected loss of transforming growth factor beta2 (TGFβ2) gene in the NC (i.e., Tgfb2 CKO) were used and compared with wildtype (i.e., normal TGFβ2 gene) to determine the role of TGFβ2 in NC migration and heart development. The NC were genetically tagged (by combining with mT/mG+/- reporter transgenic mice) by a green-fluorescent protein (GFP) in both Tgfb2 CKO and wildtype embryos to track NC migration and quantification in the heart during embryonic development. Fluorescent microscopic images of serial tissue sections of multiple embryos (three or more embryos/group) from Tgfb2 CKO and wildtype embryos. These images were captured by using GFP filters (green color) in a fluorescent microscope. The amount of GFP fluorescence (green color) was quantified by NIH Image J (Fiji) software. The data showed that the number of GFP-positive NC was significantly increased, and more NC were present in both outflow tract and inflow tract regions in Tgfb2 CKO embryos. In conclusion, the results indicate that TGFβ2 is required for a controlled cardiac NC migration, survival, and proliferation in the heart during embryonic development. This information will lead to a better understanding of the mechanisms involved in congenital heart disease