The focus of this project is the peripheral non-myelinating glia that ensheath the majority of sensory axons. Unmyelinated axons are often damaged and/or lost in neuropathies. The non-myelinating glia are thought to play key roles in the repair, degeneration and/or regeneration of the affected nerves. We have chosen to focus on the response to degeneration of sensory axons, one feature common to many neuropathies. To gain a better understanding of the mechanisms involved in the glial response to axonal damage/degeneration, we developed an inducible model of peripheral sensory nerve degeneration in zebrafish. This model permits the conditional and selective ablation of peripheral sensory neurons and their axons. In our initial studies, we have found evidence that upon axon degeneration, peripheral glia are critical to the removal of axonal debris and recruitment of immune cells to sites of the involved nerves. The hypothesis that will be tested in this proposal is that axonal damage and degeneration induces glia to alter their gene expression, resulting in phagocytic behaviors and signaling to the immune system. In this application, we propose two aims: (1) identify genes involved in the response of peripheral glia to sensory neurodegeneration and (2) to validate the candidate genes identified in Aim 1. This will be achieved through transcriptome analysis of control and metronidazole- treated fish. Validation of candidate genes will be performed using qPCR, in situ hybridization and CRISPR/Cas9 mediated deletion analysis. Identification of involved genes will provide an important foundation for future investigations into the mechanisms by which peripheral glia react to death and degeneration of sensory circuits, and can be used as the starting points for directed studies in higher vertebrates, with the eventual goal of developing new directions in clinical efforts to treat this aspect of many debilitating sensory neuropathies.

Public Health Relevance

Millions of people worldwide suffer degraded health and quality of life issues due to disorders involving the peripheral sensory nervous system. Currently, treatment of such disorders is limited by the lack of clinically useful tools. The principal goal of this project is to provide a springboard for the development of new approaches to the treatment of these diseases by identifying cellular mechanisms involved in the glial response to peripheral sensory neuron degeneration.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21NS087574-01A1
Application #
8970506
Study Section
Cellular and Molecular Biology of Glia Study Section (CMBG)
Program Officer
Morris, Jill A
Project Start
2015-05-01
Project End
2017-04-30
Budget Start
2015-05-01
Budget End
2016-04-30
Support Year
1
Fiscal Year
2015
Total Cost
$227,250
Indirect Cost
$77,250
Name
Saint Louis University
Department
Pharmacology
Type
Schools of Medicine
DUNS #
050220722
City
Saint Louis
State
MO
Country
United States
Zip Code
63103
Allen, James R; Bhattacharyya, Kiran D; Asante, Emilia et al. (2017) Role of branchiomotor neurons in controlling food intake of zebrafish larvae. J Neurogenet 31:128-137
Cox, Jane A; Zhang, Bo; Pope, Holly M et al. (2016) Transcriptome Analysis of Chemically-Induced Sensory Neuron Ablation in Zebrafish. PLoS One 11:e0148726