Teratogenic Effects of Serotonin Receptor 2B Disruption on the Migration and Cardiac Derivatives of the Cardiac Neural Crest

Abstract

Background: Cardiac neural crest cells (cNCCs) are critical for heart development, and their disruption can result in congenital heart defects. Serotonin (5-HT) signaling, specifically via 5-HT2B and 5-HT2C receptors, regulates diverse physiological processes, including neural crest migration. This study investigates how modulation of 5-HT2B and 5-HT2C receptor activity impacts cNCC migration and the development of their derivatives, with relevance to serotonergic drug safety during pregnancy. Methods: Chicken embryos at HH8 were treated with 50 μL of 20 μM 1-Methylpsilocin (1-MP), an inverse agonist of 5-HT2B and agonist of 5-HT2C, and collected at HH14 to assess cNCC migration. Embryos were pre-treated with SB242084, a selective 5-HT2C antagonist, to isolate receptor-specific contributions before 1-MP application. Phenotypic outcomes were assessed at HH32 and HH36 for structural heart defects. Results: 1-MP disrupted cNCC migration at HH14, evidenced by abnormal shortening of the circumpharyngeal neural crest (CirNCC) stream. Pre-treatment with SB242084 did not rescue the phenotype, implicating 5-HT2B as the primary driver, though potential contributions from 5-HT2C cannot be excluded. At HH32, 1-MP-treated embryos displayed gaps in the aorticopulmonary septum. By HH36, interventricular septal defects and delayed development further supported the role of 5-HT2B in cNCC migration and differentiation. Conclusion: These findings reveal that 5-HT2B receptor activity is critical for cNCC migration and heart development. They underscore the potential teratogenic risks of serotonergic drugs targeting 5-HT2B/5-HT2C receptors during pregnancy, with implications for drug safety and heart morphogenesis.