Seminars by the course instructors:

Donald Sakaguchi
Associate Professor
Department of Zoology and Genetics
Chair, Neuroscience Program
Iowa State University

Seminar title: "Differential expression of SNARE complex proteins SNAP-25, Syntaxin and VAMP during development of the mammalian retina"

Summary:

SNARE complex proteins have critical functions during regulated vesicular release of neurotransmitter. In addition, they play critical roles during neurite outgrowth and synaptogenesis. While it is clear that the function of any one SNARE complex protein during release of neurotransmitter is dependent upon its association with other members of the complex, it is less certain if their function during development and differentiation is dependent upon interaction with one another. Previously, we have observed transient high levels of SNARE complex protein SNAP-25 in developing cholinergic amacrine cells. In addition, we detected, high levels of SNAP-25 in developing and mature photoreceptors. Our results describing these patterns of expression will be discussed. In addition, I will desribe our results on the characteriztion of the changing patterns of immunoreactivity for the three SNARE complex proteins during the development and differentiation of the mammalian retina. We have compared the pattern of expression of the core SNARE complex proteins in the Brazilian opossum, Monodelphis domestica and in the rat and found common patterns of expression between these diverse mammalian species. We observed temporal differences in the onset of immunoreactivity between these three proteins, and differences in their localization within synaptic layers in the developing and mature mammalian retina. The differential distribution of SNAP-25, Syntaxin, and VAMP may indicate additional roles for these proteins during vesicle trafficking events, which are independent of their association with one another.

Suggested Reference:

West Greenlee, M.H., Roosevelt, C.R., and Sakaguchi, D.S. (2001) Differential Localization of SNARE Complex Proteins SNAP-25, Syntaxin, and VAMP During Development of the Mammalian Retina. J. Comp. Neurol. 430, No. 3: 306-320.

Michael Young
Assistant Scientist
Department of Ophthalmology
Harvard Medical School
Schepens Eye Research Institute

Seminar title: "CNS Stem Cell Transplants in Animal Models of Retinal Degeneration"

Summary:

Stem cells derived from the central nervous system are a new source for cells that may someday be used to repair the damaged brain, spinal cord, and retina. While stem cells offer great opportunities for CNS repair, there are many questions that must be addressed before they can be used in a clinical setting. These include an understanding of (and control over) differentiation, migration, immunogenicity, and proliferation. At present we know very little about any of these key factors of stem cell behavior. I will address the following questions:

1) What controls the differentiation of stem cells following grafting to sites in the CNS?
Does the local microenvironment influence the development of cell phenotype?
Brain and spinal cord vs. retina
Extraocular vs. intraocular
Can cells of specific lineage (e.g. hematopoetic stem cells) alter cell fate and trans-differentiate into cell types distinct from their respective lineage?

2) Can stem cells replace lost neurons in the diseased CNS?
What level of "replacement" can be achieved (i.e. morphological vs. functional)?

3) Do stem cells respond to injury?
If so, what might these cues be?

4) Are stem cells an immune privileged tissue?
Are they more "privileged" than conventional neural tissue?
Transplantation to conventional vs. privilege sites
Syngeneic vs. allogeneic. vs. xenogeneic

5) What surface antigens are expressed on neural stem cells?

Suggested References:

Young, M.J. , J. Ray, S.J.O. Whiteley, H.J. Klassen, F.H. Gage. 2000.
Integration of transplanted neural progenitor cells into the retina of immature and mature dystrophic rats. Molecular and Cellular Neuroscience 16: 197-205

Multipotent stem cells from the brain and retina of green mice (2001) M. A. Shatos, K. Mizumoto, H. Mizumoto, Y. Kurimoto, H. Klassen and M. J. Young e-biomed. vol. 2: 2001

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