Homocysteine intensifies embryonic LIM3 expression in migratory neural crest cells: A quantitative confocal microscope study

Elevated levels of homocysteine in maternal blood and amniotic fluid are associated with cardiovascular, renal, skeletal, and endocrine diseases and also with embryonic malformations related to neural crest cells. Neural crest cells are necessary for the formation of tissues and organs throughout the body of vertebrate animals. The migration of neural crest cells is essential for proper development of the target tissues. When migration is disrupted, abnormalities may occur. Migration is affected by transcriptional factor LIM3 protein, which regulates the dynamic components of the neural crest cell cytoskeleton. The objective of this study was to test the hypothesis that exogenous homocysteine would induce greater LIM3 protein expression in neural crest cells. We predicted homocysteine increases the expression of LIM3 protein in migrating neural crest cells, causing improper assembly and organization of actin filaments during cellular migration. We dissected homocysteine treated and control chick embryos at developmental stage 15. The explants were immunostained and sectioned on to slides. We found that the expression of LIM3 protein was significantly enhanced in the areas surrounding the neural tube, the pharynx, and in the periocular mesenchyme of embryos that were subjected to elevated plasma homocysteine when compared to control embryos. Our results support that homocysteine can enhance or alter the migration and behavior or neural crest cells by affecting the cytoskeleton regulation of LIM3 protein.