HuR Function and Translational State Analysis Following Global Brain Ischemia and Reperfusion

• Published in: Translational stroke research 2013-12, Vol.4 (6), p.589-603
• Main Authors: Szymanski, Jeffrey J., Wang, Haihui, Jamison, Jill T., DeGracia, Donald J.
• Format: Article
• Language: English
• Subjects: Adenine - metabolism; Animals; Biomedical and Life Sciences; Biomedicine; Blotting, Western; Brain; Brain Ischemia - metabolism; CA1 Region, Hippocampal - metabolism; CA3 Region, Hippocampal - metabolism; Cardiology; Carotid arteries; Dissection; ELAV Proteins - metabolism; Homogenization; HSP70 Heat-Shock Proteins - metabolism; Hypotension; Investigations; Ischemia; Laboratory animals; Male; Neurology; Neurons - metabolism; Neurosciences; Neurosurgery; Original Article; Proteins; Rats; Rats, Long-Evans; Regulation; Reperfusion Injury - metabolism; RNA, Messenger - metabolism; Uridine - metabolism; Vascular Surgery
• ISSN: 1868-4483; 1868-601X
• DOI: 10.1007/s12975-013-0273-2

Prolonged translation arrest in post-ischemic hippocampal CA1 pyramidal neurons precludes translation of induced stress genes and directly correlates with cell death. We evaluated the regulation of mRNAs containing adenine- and uridine-rich elements (ARE) by assessing HuR protein and hsp70 mRNA nuclear translocation, HuR polysome binding, and translation state analysis of CA1 and CA3 at 8 h of reperfusion after 10 min of global cerebral ischemia. There was no difference between CA1 and CA3 at 8 h of reperfusion in nuclear or cytoplasmic HuR protein or hsp70 mRNA, or HuR polysome association, suggesting that neither mechanism contributed to post-ischemic outcome. Translation state analysis revealed that 28 and 58 % of unique mRNAs significantly different between 8hR and NIC, in CA3 and CA1, respectively, were not polysome-bound. There was significantly greater diversity of polysome-bound mRNAs in reperfused CA3 compared to CA1, and in both regions, ARE-containing mRNAs accounted for 4–5 % of the total. These data indicate that posttranscriptional ARE-containing mRNA regulation occurs in reperfused neurons and contributes to post-ischemic outcome. Understanding the differential responses of vulnerable and resistant neurons to ischemia will contribute to the development of effective neuroprotective therapies.