Downregulation of PEBP1 in Rat Brain Cortex in Hypoxia

Abstract

In order to understand dementia and other ailments associated with high altitude hypoxia, adult Sprague Dawley male rats were exposed to simulated conditions of high altitude (7,500 m above sea level, 59 mmHg) for a period of 5 days and analyzed for changes in neuronal proteome by 2-D sodium dodecyl sulfate polyacrylamide gel electrophoresis. Protein extracts obtained from the brain cortex and hippocampus of the hypoxic rats were separated by 2-D gel electrophoresis. Differentially expressed proteins (analysis by 2-D gel analysis software, Bio-2D, Vilber-Lourmat, France and Delta2d, Decodon, Germany) were subjected to matrix-assisted laser desorption/ionization time-of-flight analysis. Among the proteins identified, the spot corresponding to pI 5.4 and molecular weight 21 kDa, identified as phosphatidylethanolamine binding protein (PEBP1), was consistently lowered (54%) in hypoxic cortex samples. PEBP1, also known as Raf kinase inhibitor protein, is a precursor of hippocampus cholinergic neurostimulatory peptide (HCNP). Western blot analysis revealed elevated phospho-extracellular signal-regulated kinase in hypoxic rat cortex samples, indicating activation of Raf/mitogen-activated protein kinase pathway under hypoxia. Lowered HCNP levels leading to 23% decrease in choline acetyltransferase and 63% increase in acetylcholinesterase activity were detected in hypoxic rat brain cortex, while no significant change was noted in hippocampus. Since PEBP1 is lowered in a number of neurological disorders associated with dementia, we speculate that lowered expression of PEBP1 might be responsible for dementia associated with high-altitude hypoxia. Further studies targeting PEBP1 might give clues about signaling pathways associated with hypoxia and dementia.

Comparison between the effect of human Wharton’s jelly–derived mesenchymal stem cells and levetiracetam on brain infarcts in rats

“…Peroxynitrite mediates NO-induced blood brain barrier (BBB) damage and mediate apoptotic cell death. 52 Overexpression of Cu/ZnSOD attenuates neuronal death when focal brain ischemia confers neuroprotection. The effects of LEV and WJ-MSCs may be due to the increased expression of the neurotrophic factors BDNF, GDNF, and PEBP1 and antioxidant molecule Cu/ZnSOD in the brain tissue of treated animals, as they protect neurons from mechanisms related to ischemic insult.…”

β‐N‐Oxalyl‐l‐α,β‐diaminopropionic acid regulates mitogen‐activated protein kinase signaling by down‐regulation of phosphatidylethanolamine‐binding protein 1

“…1999, 2001). Previous work from our laboratory indicated PEBP1 to be down‐regulated in hypoxia (Burgula et al. 2009), a condition where HIF‐1α is stabilized.…”

“…1999, 2000). Furthermore, results from our previous study indicated PEBP1 to be down‐regulated under hypoxia (Burgula et al. 2009).…”

“…As a preliminary study, we analyzed important transcriptional factors NFκB, AP‐1 and HIF‐1α in response to l ‐ODAP treatment and found HIF‐1α to be preferentially activated and translocated to the nucleus in response to l ‐ODAP whereas NFκB and AP‐1 showed no detectable nuclear localization and DNA‐binding activity. Previous studies indicated no significant change in PEBP1 levels (Burgula et al. 2009) upon induction of hypoxia mimicking conditions using Cobalt chloride and Desferroxamine (Shrivastava et al.…”

“…Cloning of Rat PEBP1 gene into bacterial expression vector pGEX4T‐1 was performed previously in our laboratory (Burgula et al. 2009).…”