POWRE: Vesicle Trafficking in Hippocampal Astrocytes

University Of Colorado At Denver, Aurora CO

Investigators

Abstract

There are two main types of cells in the brain: neurons and glia. Traditionally glia have been thought to be passive cells whose main function is to provide support for neurons. Recent studies, however, indicate that glial cells form a vast network that is actively involved in transfer of information over relatively long distances. This project has two main aims: 1. How do one kind of glial cells, the astrocytes, communicate with each other? Preliminary data indicate that astrocytes can secrete neurotransmitters and growth factors when stimulated. This project will examine the nature of vesicles that store these chemicals in the cell. Vesicle trafficking in astrocytes will be examined using fluorescent dyes to specifically label vesicle membranes. Astrocytes will then be imaged using sensitive CCD cameras and vesicles followed over time. Changes that occur upon stimulation of the cell will be recorded. 2. Are there specialized areas between astrocytes and neurons that facilitate communication between the two cell types? The hypothesis is that if there are such areas and stimulation of astrocytes should reveal microdomains of increased activity. In addition, these "hot-spots" should be in close proximity to processes of neurons. This will be studied in two ways (a.) Since calcium is essential for communication between cells, increases in calcium concentration (as indicated by calcium sensitive dyes) in well-defined areas of the cell upon stimulation will indicate the presence of hot-spots. (b.) Examination of cells under an electron microscope will expose the ultra-microscopic architecture of astrocytes revealing the presence of any intimate association with neuronal cells. In summary, the aim of this project is to examine the basic cell biology of communication between cells in the brain, especially how astrocytes modulate brain function. Funding of this POWRE project will also enable a beginning investigator to acquire preliminary data towards a larger proposal, and enhance her credentials and opportunities for an independent academic position.