In vivo analysis of TrkA function in chicken embryos

• Grant number: 23/04849-2
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: August 01, 2023
• End date: July 31, 2024
• Field of knowledge: Biological Sciences - Morphology - Embryology
• Principal Investigator: Deborah Schechtman
• Grantee: Felipe Monteleone Vieceli
• Supervisor: Marcos Simões Costa
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Harvard University, Boston, United States
• Associated to the scholarship: 20/13929-1 - Effects of CIPA-associated mutations in TrkA on the pain signaling pathways and development of nociceptive neurons, BP.PD

Abstract

Pain signaling is conducted by nociceptors, which derive from the neural crest and reside in dorsal root ganglia. Inflammatory pain relies on activation of TrkA receptors by NGF, which initiates signaling pathways that trigger action potentials. TrkA activation by NGF also promotes neuronal survival and differentiation during development. Mutations in NTRK1, which encodes TrkA, cause congenital insensitivity to pain due to developmental loss of nociceptors or incomplete differentiation and sub-optimal pain signaling. Although NTRK1 mutations have been studied in vitro, it has remained elusive how these results recapitulate what happens in vivo. In this project, we set out to generate chicken models of TrkA-caused congenital insensitivity to pain. Preliminary results suggest that TrkA may also regulate neural crest migration and target colonization. Although cell survival phenotypes may be addressed with analysis of immunostained cross sections, comprehensive analyses of neural crest migration and nociceptor differentiation in vivo by live imaging and/or 3D reconstruction, ideally by light-sheet fluorescence microscopy, require availability of specific equipment and software not readily available in Brazil. Further, our project would greatly benefit from the identification of nociceptor enhancers capable of driving cell type-specific transgene expression. To achieve these goals, we propose a one-year internship at Dr. Simões-Costa's laboratory at the Harvard Medical School, where state-of-the-art microscopes are available for frequent use and single-cell RNA-Seq and ATAC-Seq data from developing sensorial neurons is currently being generated. With these results, we hope to determine how TrkA mutants differently affect its downstream pathways and developmental functions. (AU)