Semaphorin 3a Lab Report

David Shabazi

BIOL476

Cindy Malone

11/1/17

Semaphorin Signaling Regulates Vascular and Hematopoietic Regeneration

Dr. Heather Himburg, Ph.D’s lab utilizes semaphorin 3A signaling to promote bone marrow and vascular recovery following radiation injury. Semaphorin 3A, or SEMA3A for short, is a protein that’s heavily involved in the regulation of patterns in normal neuronal development. Himburg focuses on treating radiation damage in particular because of the following reasons. 1.) Victims of radiation exposure can get the proper treatment they need, 2.) Proper techniques will develop to condition the victims that received bone marrow radiation damage (because they will need a bone marrow transplant in the near future), and 3.) therapies

This was a good target to pick for an additional reason: vascular endothelial cells

There was a control group and several experimental groups; each experimental group was exposed to radiation for a different amount of time, while the control group had no exposure. They found that each gene yielded different gene signatures at each time point, where some experimental groups had higher amount of cell apoptosis or even cell necrosis. This higher death was associated with higher SEMA3A expression, so it was found that SEMA3A upregulation induces EC apoptosis (endothelial cell apoptosis). Because of this finding, their next experiment was to observe the effects of SEMA3A upregulation, as a way to treat radiation injury more efficiently and prevent a high amount of cell apoptosis. They noticed interesting things about CDK5 which, like SEMA3A, also plays an important role in the nervous system. When an EC colony is exposed to radiation alone, CDK5 expression is induced. Later analysis revealed that the expression of SEMA3A also increases CDK5 expression, so it’s a chain