Chemical Induced Hypoxia Differentially Affects Gene Expression in Human Neuronal Cells

<p>Previously, our laboratory used desferoxamine (DFO), to generate hypoxic conditions (a low oxygen condition) which decreased human neuronal cell viability, but some cells still survived. These surviving neurons showed no morphological changes when compared to the non-treated group. However, the alteration of several intracellular events were detected, such as an increase of hypoxia inducible factor 1 (HIF-1) mRNA levels, a decrease of human mu opioid receptor (hMOR) message, and no change of human delta opioid receptor (hDOR) receptor message. Western blot analysis showed the Janus kinase (JAK)/ Signal Transducers and Activators of Transcription (STAT) pathway was activated and an increase in STAT3 (P-STAT3) levels at was observed at 12 and 24 hour treatment. Heavy metal compounds such as cobalt chloride (CoCl₂) can also cause hypoxia in cells. To investigate adaptive responses of human neuronal cells under CoCl₂versus DFO induced hypoxic conditions, we examined the expression of several opioid receptor genes. Preliminary results of RT-PCR showed a decrease in hMOR message levels, no change in hDOR message levels and a significant increase in hKOR message levels. Taken together, these results showed that similar adaptive responses were developed under DFO or CoCl₂ induced hypoxia, suggesting that opioid receptor expression may be linked to neuronal survival. The JAK/STAT pathway was also examined using confocal analysis. DFO treated cells showed an increase in P-STAT3 levels in the nucleus after 24 hours, while CoCl₂ treated cells showed a decrease in P-STAT3 levels after 24 hours. Collectively, these two compounds activated the JAK/STAT pathway at different times, implicating that JAK/STAT may have a differential role when different compounds (DFO or CoCl₂) are used to induce hypoxic conditions. Further understanding these mechanisms will assist to identify potential therapeutic targets in the future.</p>

Name thesis:degree_name

MS Biology

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Biology

Year dc:date.available

2014

Author dc:creator

• Pavlichko, Natasha V.

Contributors dc:contributor

• Jane L. Ko, PhD
• Edward Tall, PhD
• Angela V. Klaus, PhD

• Chemical-Induced Hypoxia
• Gene Expression
• Neuronal Cells
• Biology
• Cell Biology

Repository record dc:identifier

https://scholarship.shu.edu/dissertations/1975

OAI identifier oai:identifier

oai:scholarship.shu.edu:dissertations-2989