On the right track: building the neural circuitry for feeding and swallowing

Sponsored by: Leica Microsystems

Speaker

Zahra Motahari, PhD

Postdoctoral Scientist, George Washington University, Laboratory of Drs. Anthony LaMantia and Sally Moody
BIOGRAPHY

Event Date & Time

DATE: October 16, 2018

TIME: 7:00am PDT, 10:00am EDT

Abstract

22q11 Deletion Syndrome (22q11DS) is a genomic disorder caused by a microdeletion of chromosome 22 that occurs with the prevalence of 1:4000 live births. 22q11DS patients have neurodevelopmental disabilities associated with feeding and swallowing difficulties that compromise their nutritional status and increase the risk of nasal, middle ear, and respiratory infections due to aspiration and reflux. Although the causes are unknown, studies in LgDel mouse model of 22q11DS suggest the aberrant development of several cranial nerves that are derived from cranial neural crest and placodes. Particularly affected is the trigeminal nerve (CNV) that provides sensory innervation to the face and oral cavity as well as motor innervation to the muscles of mastication.

To better assess CNV outgrowth and development in these animals, we used Alexa Flour 594 biocytin neural tracer to retrogradely label the axonal trajectories in whole moue embryos. Biocytin was injected into branchial arch 1B of E11.5 embryos with a broken glass micropipette under microscopic observation. Embryos were incubated in cell culture medium for an hour at 37C, fixed and then processed for 3D imaging.

Our results show that in wild type animal both sensory and motor CNV axons projects directly toward their final target. LgDel CNV axons, however, exhibits abnormal phenotype including looping, branching, misrouting, and sprouting suggesting that axonal pathfinding is compromised. Our innovative approach could determine if defective peripheral cues are at last partially responsible for abnormal CV development in LgDel embryos, thus contributing to their feeding difficulties after birth.

Learning Objectives: