The Effects Of Protease Activated Receptor-1 (PAR-1) Activation On Motor Neuron Axon Extension In A 3-D Collagen Matrix Model

Noa Camp

School Name

South Carolina Governor's School for Science and Mathematics

Grade Level

12th Grade

Presentation Topic

Microbiology

Presentation Type

Mentored

Mentor

Mentor: Victoria Turgeon, Biology Department, Furman University

Abstract

Motor neurons are nerve cells that originate in the spinal cord and are responsible for muscular control. Axons extending into the periphery from these motor neurons are very prone to damage. This kind of damage often also results in breakdown of nearby blood vessels, releasing thrombin, an activator of protease-activated receptor-1 (PAR-1). Thrombin activates PAR-1 by cleaving off a receptor cap, exposing the 7-amino acid sequence SFLLRNP, which then binds to a site on its own receptor. Previous studies have shown that PAR-1 activation on motor neurons grown in 2D culture causes less overall branching off the neurons and shorter axons. This project examines how PAR-1 activation affects axon growth in a 3D collagen matrix. To ensure that the axons grow in the proper direction, a collagen matrix containing nerve growth factor was placed at the bottom of the chamber and then topped with a matrix seeded with chick embryo motor neurons. Test groups were treated with 100µM SFLLRNP; whereas controls received an equal volume of medium. Collagen matrices were collected at 24, 48, 72, and 96 hour time periods after treatment and processed for immunocytochemistry. Cells were stained with anti-vinculin for focal adhesion points, TRITC-phalloidin for the processes and DAPI for the nuclei. Stained cells were photographed and axon lengths were measured. Preliminary results suggest that motor neuron axon growth rate is hindered by PAR-1 activation in the presence of SFLLRNP.

Start Date

4-11-2015 10:00 AM

End Date

4-11-2015 10:15 AM

COinS
 
Apr 11th, 10:00 AM Apr 11th, 10:15 AM

The Effects Of Protease Activated Receptor-1 (PAR-1) Activation On Motor Neuron Axon Extension In A 3-D Collagen Matrix Model

Motor neurons are nerve cells that originate in the spinal cord and are responsible for muscular control. Axons extending into the periphery from these motor neurons are very prone to damage. This kind of damage often also results in breakdown of nearby blood vessels, releasing thrombin, an activator of protease-activated receptor-1 (PAR-1). Thrombin activates PAR-1 by cleaving off a receptor cap, exposing the 7-amino acid sequence SFLLRNP, which then binds to a site on its own receptor. Previous studies have shown that PAR-1 activation on motor neurons grown in 2D culture causes less overall branching off the neurons and shorter axons. This project examines how PAR-1 activation affects axon growth in a 3D collagen matrix. To ensure that the axons grow in the proper direction, a collagen matrix containing nerve growth factor was placed at the bottom of the chamber and then topped with a matrix seeded with chick embryo motor neurons. Test groups were treated with 100µM SFLLRNP; whereas controls received an equal volume of medium. Collagen matrices were collected at 24, 48, 72, and 96 hour time periods after treatment and processed for immunocytochemistry. Cells were stained with anti-vinculin for focal adhesion points, TRITC-phalloidin for the processes and DAPI for the nuclei. Stained cells were photographed and axon lengths were measured. Preliminary results suggest that motor neuron axon growth rate is hindered by PAR-1 activation in the presence of SFLLRNP.