Puerarin attenuates glutamate-induced neurofilament axonal transport impairment.
OBJECTIVE
Puerarin (Pur) is a primary component of the most functional extracts of Pueraria lobata used in traditional Chinese medicine for centuries. Since it has been postulated that Pur protects the brain against glutamate (Glu) neurotoxicity, we investigated the effects of Pur on Glu-induced axonal transport impairment in primary hippocampal neurons in this study.


METHODS
Primary hippocampal cultures were prepared from 2-day-old Sprague-Dawley rats. Intracellular calcium concentration [Ca(2+)](i), neurofilament (NF) phosphorylation and protein kinase activity for Cdk5 were measured. Time-lapse imaging technology was used to capture the NF axonal transport in the cultured neurons with transiently transfected fluorescence protein linked to the N-terminus of NF-M (EGFP-NFM).


RESULTS
The results showed that Pur significantly diminished the Glu-induced elevation of [Ca(2+)](i) in dose-dependent manner and antagonized the Glu-evoked increases in NF phosphorylation at protein levels. The neurons under the Glu treatment displayed the accumulation of immobile NF clusters in the cell body and the reduced rates of axonal transport of NFs by 72.8% compared to the control neurons. Intriguingly, Pur reversed the slowed rate of the axonal transport by 35.6%. Pur also remarkably attenuated Glu-evoked activation of Cdk5.


CONCLUSIONS
Pur may play a role in protecting against Glu-induced NF axonal transport impairment in rat primary hippocampal neurons by inhibiting the increased [Ca(2+)](i) and by impeding the activation of Cdk5.
Zhou
Jie
J
Department of Biochemistry and Molecular Biology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Wang
Hongxing
H
Xiong
Yufang
Y
Li
Zixi
Z
Feng
Youmei
Y
Chen
Juan
J
D000818:Animals; D000831:Animals, Newborn; D001370:Axonal Transport / Q000187:drug effects*; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects*; D007529:Isoflavones / Q000302:isolation & purification / Q000494:pharmacology*; D018613:Microscopy, Confocal; D015394:Molecular Structure; D016900:Neurofilament Proteins / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D010766:Phosphorylation; D029908:Pueraria / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
D007529:Isoflavones; D016900:Neurofilament Proteins; D018698:Glutamic Acid; D051360:Cyclin-Dependent Kinase 5; C495907:Cdk5 protein, rat; D002118:Calcium; C033607:puerarin