Cellular migration is necessary for proper embryonic development as well as maintenance of adult health. Cells can migrate individually or in groups in a process known as collective cell migration. These cohorts of cells maintain cell-cell contact, group polarization and exhibit coordinated behavior. Collective cell migration is important in numerous processes during development including blood vessel branching and neural crest cell migration as well as in adulthood in wound healing. Additionally, this process is misappropriated during cancer cell invasion. During individual and collective cellular migration, cells must extend protrusions to interact with the extracellular environment, sense chemotactic cues, and act as points of attachment. The mechanisms and regulators of protrusive behavior have been widely studied in populations of cells that migrate individually; however, how protrusive behavior is regulated throughout collectives is not well understood. Specifically, it has been difficult to define protrusive behavior of cells inside the collective, as these cells are tightly packed. I am using the zebrafish posterior lateral line primordium (pLLP) as a model of collective cell migration in order to examine the regulation of protrusive behavior during collective cell migration. The pLLP is a cluster of around 100 cells that migrates along both lateral sides of the zebrafish, depositing groups of cells that will become sensory organs. These sensory organs make up the posterior lateral line (pLL), a mechanosensory system responsible for sensing changes in water current.
I aim to use advantages of this system, including amenity to live imaging and genetic approaches, to define protrusive behavior throughout the pLLP and identify factors that regulate this behavior during collective cell migration. Towards this goal, I have performed mosaic analysis to sparsely label small numbers of cells in the pLLP with a transgene that marks filamentous actin. This approach revealed an abundance of brush-like actin-based protrusions in multiple cells across the pLLP. To identify genes that regulate protrusive behavior, I have examined expression of candidate genes, including those that are regulated by canonical Wnt signaling. Within the pLLP, canonical Wnt signaling is important for a number of cellular behaviors including migration. In the absence of Wnt signaling, the pLLP migrates abnormally, resulting in truncation of the pLL. We have found a number of Wnt target genes that regulate actin dynamics and thus might regulate protrusive behavior. Moreover, my preliminary data show that a subset of these genes is expressed in specific regions of the pLLP, and their expression pattern is perturbed under Wnt- deficient conditions. Based on this preliminary data, I will: define protrusive behavior throughout the pLLP and determine the role of Wnt signaling in regulating this behavior (Aim 1); and identify regulators of protrusive behavior during collective cell migration (Aim 2). Further elucidation of the regulation of protrusive behavior during collective cell migration could define new mechanisms of organ development as well as how these mechanisms are misappropriated during cancer cell invasion.

Public Health Relevance

Collective cell migration is necessary for many biological processes both during development and in adulthood, and is often misappropriated during cancer cell invasion. In order for proper migration collectives must regulate protrusive behavior, however, the regulation of this behavior during collective cell migration is not well understood. This project aims to understand how protrusive behavior is regulated during collective cell migration in hopes of elucidating mechanisms of organ development as well as shed light on potential mechanisms used by invasive cancer cells.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Predoctoral Individual National Research Service Award (F31)
Project #
1F31HD095606-01A1
Application #
9681839
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Mukhopadhyay, Mahua
Project Start
2018-11-01
Project End
2021-10-31
Budget Start
2018-11-01
Budget End
2019-10-31
Support Year
1
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Oregon Health and Science University
Department
Neurosciences
Type
Overall Medical
DUNS #
096997515
City
Portland
State
OR
Country
United States
Zip Code
97239