Research Description

Comparative Analysis between Neuroprotection by Estrogen and Neuroprotection by Engineered Protein

Glucocorticoids are steroids that are released during stress and are often found in excess after brain injury. At high levels, they activate the wildtype glucocorticoid receptor (GR) and compromise neuronal survival after injury. The harmful effects of glucocorticoids are partially mediated through the translocation of the activated GR to the nucleus, where it exerts its transcription effects. In contrast, estrogen plays a neuroprotective role after brain injury. In the presence of estrogen, the activated the estrogen receptor (ER) translocates to the nucleus and upregulates the production of Brain Derived Nerve Growth Factor (BDNF), a neurotrophin that aids in neuronal survival. Kaufer et al. developed two methods to help limit the deleterious effects of glucocorticoids. One was the ER/GR chimeric receptor (ER/GR). The ER/GR, in addition to blocking the translocation of GR into the nucleus, also transduces the glucocorticoid signal to an estrogenic response.

The main goal of this study is to determine whether the presence of the ER/GR offers an enhanced neuroprotective effect in comparison to that of the ER alone. The first step is to develop a quantitative translocation assay to see how the ER/GR affects the translocation of the wildtype GR and ER receptors. To do this assay, I will first study the translocation of wildtype GR and ER in the presence of glucocorticoids and estrogen. This assay would then be followed by a quantitative assay of the translocation of wildtype GR and ER in the presence ER/GR. It is expected ER/GR will block the translocation of wildtype GR. However, its effect on the translocation of ER are unknown. If it is shown that ER/GR does not block the translocation of ER, the next step is to study the effect of ER/GR on the production of BDNF. The final step of this study will be to compare the neuroprotective effect of ER/GR to the neuroprotective effect of ER alone. Here, the hippocampal cells will be treated with Kainic Acid (KA), an excitotoxin that injures neurons. The survival of neurons after treatment with KA in the presence of ER/GR or ER will then be determined.