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Pascale Nelson

Undergraduate Major:Biotechnology

Future Plans:Graduate program in Biotechnology

Pascale Nelson

Pascale Nelson was born and raised in Brooklyn, NY, Pascale has lived in Orlando, FL for seven years. Pascale is currently pursuing a degree in Biotechnology with a minor in Psychology. She is currently involved in research at UCF Biomedical College with a focus in ALS disease under the supervision of Dr. Alvaro G. Estevez. After graduation, Pascale aspires to earn a doctoral degree in Biotechnology.

Title: Nitrated Hsp90-induced PC12 cell apoptosis requires p38 and JNK MAP kinase activation

Conducted at the University of Central Florida as part of the McNair Scholars Program and the NSF funded UCF ICubed Program.

Mentor: Dr. Alvaro Estevez, University of Central Florida, Burnett School of Biomedical Science

Abstract: The oxidant peroxynitrite is formed by the diffusion-limited reaction of nitric acid and superoxide. Nitrotyrosine, footprint of peroxynitrite formation, is present in neurodegenerative diseases. Recently we have shown that tyrosine nitration plays a role in peroxynitrite-induced apoptosis. Peroxynitrite induces apoptosis in many cell lines, including PC12 cells. The incubation of PC12 cells with peroxynitrite leads to the activation of p38 and the c-Jun-N-terminal (JNK) MAP kinase pathways. A target of nitration in PC12 cells is the protein chaperone heat shock protein-90 (Hsp90), which when nitrated stimulates cell death. We hypothesize that nitration of Hsp90 mediates peroxynitrite toxicity. Peroxynitrite-treated Hsp90 delivered intracellularly using the membrane-permeating agent Chariot stimulates 39.9 +/- 4.9% PC12 cell death. Recombinant Hsp90 with nitrotyrosine in residues 33/56 (Hsp9033/56), produced by non-native amino acid incorporation, also stimulated 31.4 +/- 8.1% PC12 cell death. Inhibition of p38 and JNK MAP kinases prevented nitrated Hsp90-induced PC12 cell apoptosis. Caspase inhibitors also inhibited cell death. Like for peroxynitrite, nitrated Hsp90 stimulated the phosphorylation of p38 and JNK MAP kinases, which peaked 1 and 4 hours after intracellular delivery of the chaperone for JNK MAP kinases and p38 kinases respectively. Our results show that nitrated Hsp90 mimics the effects of peroxynitrite on the induction of apoptosis and the activation of MAP kinases.

Title: Construction of a Fork Head Responsive Element Reporter to monitor Signaling Pathways in Motor Neurons 

Conducted at the University of Central Florida as part of the Research and Mentoring Program

Mentor: Dr. Alvaro G. Estevez

Abstract: Geldanamycin is an inhibitor of the protein chaperone heat shock protein 90 (Hsp90). Hsp90 inhibitors are in clinical trials for cancer. In addition, geldanamycin protects against excitotoxicity in primary cortical cultures. We found that primary motor neuron cultures are 10-104 times more sensitive to inhibition of Hsp90 by geldanamycin than cultured cortical neurons at low and high-density, dissociated spinal cord cultures, and the differentiated and undifferentiated hybrid motor neuron cell line NSC34. In primary motor neurons, geldanamycin inhibition of Hsp90 activates Fas-dependent apoptosis. Upstream of Fas activation, incubation of motor neurons with geldanamycin induces Fas ligand expression. Expression of FasL is dependent on the translocation of nuclear factor Forkhead box O3a (FOXO3a) to the nucleus and binding to Fork Head Responsive Element (FHRE). Currently we have preliminary results showing that FOXO3a translocated to the nuclei. The luciferase reporter vector containing the FHRE will be use to demonstrate activation of the promoter by geldanamycin. We will also use a dominant negative FOXO3a to reverse the effects of geldanamycin. These results will provide incontrovertible evidence for the role of FOXO3a in the induction motor neuron apoptosis by geldanamycin.