Prenatal Glucocorticoid Exposure and Congenital Abdominal Wall Defects: Involvement of CXCR4 - SDF-1 Signaling.

Abstract

Developmental defects of the ventral abdominal wall, such as gastroschisis, have been associated with prenatal stress exposure. To investigate this further, dexamethasone (DEX), a synthetic glucocorticoid, was administered to fertilized chicken eggs on day 1 of incubation to simulate stress, and embryonic development was subsequently analyzed through in-situ hybridization, immunohistochemistry, and histological methods. Significant developmental abnormalities were displayed by DEX-treated embryos, including open abdomens, reduced MYOG expression in the abdominal wall, and disrupted muscle fiber formation, as indicated by altered Myosin heavy chain patterns. Additionally, early markers of muscle development, such as Pax3, and the CXCR4-SDF-1 signaling axis, crucial for the migration of myogenic precursors of the dermomyotome, were markedly affected. Significant alterations in the expression of mesenchymal markers, including Vimentin and Fibronectin in the lateral plate mesoderm, were observed, alongside alterations in Pitx2, BMP4 and TFAP2A expression. Importantly, a downregulation of Glucocorticoid Receptors was identified, emphasizing the chronic stress exposure. These results provide critical insights into how DEX interferes with key developmental pathways, particularly those involving chemokines like CXCR4 and SDF-1, and other markers of mesodermal differentiation. An advancement in the understanding of the mechanisms underlying ventral abdominal wall defects in the context of prenatal stress is provided by this research, with potential implications for preventing these congenital anomalies.