title: Neuroprotective effect of water extract of Panax ginseng on corticosterone-induced apoptosis in PC12 cells and its underlying molecule mechanisms.
abstract: BACKGROUND
  The root of Panax ginseng C.A. Meyer (Family Araliaceae) is an important medicinal plant which has been employed as a panacea for more than 2,000 years in China. It has the actions of invigorating primordial qi, recovering pulse and desertion, engendering liquid, and calming spirit. The water extract of Panax ginseng (WEG) has been used to treat kinds of central nervous system disorders, such as depression, insomnia, Alzheimer׳s disease and Parkinson׳s disease. Our previous work has demonstrated that WEG possessed antidepressant-like activities in both acute and chronic stress models of depression. Nevertheless, there are no studies on the cytoprotection and potential mechanisms of WEG on corticosterone-induced apoptosis. The present study focuses on cytoprotection against corticosterone-induced neurotoxicity in PC12 cells and its underlying molecule mechanisms of the antidepressant-like effect of WEG.
  
  
  METHODS
  The PC12 cells were treated with 250 μmol/L corticosterone in the absence or presence of WEG for 24h, then 3-(4,5-dimethy thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) detection, Hoechst33342 staining and TUNEL staining were investigated to confirm the neuroprotection of WEG. Then, mitochondrial permeability transition pore (mPTP), mitochondrial membrane potential (MMP), intracellular Ca(2+) ([Ca(2+)]i), reactive oxygen species (ROS) concentration, and the expression level of glucocorticoid receptor (GR), heat shock protein 90 (Hsp90), histone deactylase 6 (HDAC6), glucose-regulated protein 78 (GRP78), growth arrest and DNA damage inducible protein 153 (GADD153), X-box DNA-binding protein-1 (XBP-1), caspase-12, cytochrome C, inhibitor of caspase-activated deoxyribonuclease (ICAD), caspase-3 and caspase-9 were assessed by Western Blot analysis to understand the molecule mechanisms of neuroprotection of WEG.
  
  
  RESULTS
  WEG partly reversed corticosterone-induced damage in PC12 cells, which increased cell viability, decreased LDH release, and attenuated corticosterone-induced apoptosis as compared with the corticosterone-treated group. Mechanistically, compared with the corticosterone-treated group, WEG strongly attenuated [Ca(2+)]i overload and ROS level, and restored mitochondrial function, including mPTP and MMP. Furthermore, WEG strongly up-regulated the expression of GR and HDAC6, and down-regulated the expression of Hsp90, cytochrome C, ICAD, caspase-3, caspase-9 as well as endoplasmic reticulum (ER) stress-related proteins, such as GADD153, GRP78, XBP-1, and caspase-12.
  
  
  CONCLUSIONS
  WEG possessed neuroprotection against corticosterone-induced damage in PC12 cells, and the underlying molecule mechanisms was depended on the intervening of HDAC6 and HSP90 of the GR-related function proteins, and subsequent restoration of ER and mitochondria functions.
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Yumao
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Zongyang
authors.initials: Z
authors.lastname: Li
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Yamin
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Xinmin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Chang
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China.
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Liao
authors.affiliation: Institute of Medicinal Plant Development, Chinese Academy of Medical Science, Peking Union Medical College, Beijing 100193, China. Electronic address: rlpan@implad.ac.cn.
authors.forename: Ruile
authors.initials: R
authors.lastname: Pan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D003345:Corticosterone / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism; D059865:Endoplasmic Reticulum Stress / Q000187:drug effects*; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism; D000083162:Mitochondrial Permeability Transition Pore; D018696:Neuroprotective Agents / Q000494:pharmacology*; D016716:PC12 Cells; D005894:Panax; D010936:Plant Extracts / Q000494:pharmacology*; D018517:Plant Roots; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D011965:Receptors, Glucocorticoid / Q000378:metabolism*; D012997:Solvents / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D051017:Apoptosis Regulatory Proteins; D018841:HSP90 Heat-Shock Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000083162:Mitochondrial Permeability Transition Pore; D018696:Neuroprotective Agents; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D011965:Receptors, Glucocorticoid; D012997:Solvents; C109664:caspase-activated DNase inhibitor; D014867:Water; D045304:Cytochromes c; D007770:L-Lactate Dehydrogenase; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; C545556:HDAC6 protein, rat; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases; D002118:Calcium; D003345:Corticosterone
keywords: Endoplasmic reticulum stress; Glucocorticoid receptor; Heat shock protein 90; Histone deactylase 6; Mitochondria stress; Panax ginseng C.A. Meyer