Chenlei Zhu

Publications (2)5.93 Total impact

• Source

  Available from: PubMed Central

  Article: α7 nicotinic acetylcholine receptor-mediated neuroprotection against dopaminergic neuron loss in an MPTP mouse model via inhibition of astrocyte activation.

  Yuan Liu, Jun Hu, Jie Wu, Chenlei Zhu, Yujian Hui, Yaping Han, Zuhu Huang, Kevin Ellsworth, Weimin Fan
  [show abstract] [hide abstract]
  ABSTRACT: Although evidence suggests that the prevalence of Parkinson's disease (PD) is lower in smokers than in non-smokers, the mechanisms of nicotine-induced neuroprotection remain unclear. Stimulation of the α7 nicotinic acetylcholine receptor (α7-nAChR) seems to be a crucial mechanism underlying the anti-inflammatory potential of cholinergic agonists in immune cells, including astrocytes, and inhibition of astrocyte activation has been proposed as a novel strategy for the treatment of neurodegenerative disorders such as PD. The objective of the present study was to determine whether nicotine-induced neuroprotection in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model occurs via α7-nAChR-mediated inhibition of astrocytes. Both in vivo (MPTP) and in vitro (1-methyl-4-phenylpyridinium ion (MPP+) and lipopolysaccharide (LPS)) models of PD were used to investigate the role(s) of and possible mechanism(s) by which α7-nAChRs protect against dopaminergic neuron loss. Multiple experimental approaches, including behavioral tests, immunochemistry, and stereology experiments, astrocyte cell cultures, reverse transcriptase PCR, laser scanning confocal microscopy, tumor necrosis factor (TNF)-α assays, and western blotting, were used to elucidate the mechanisms of the α7-nAChR-mediated neuroprotection. Systemic administration of nicotine alleviated MPTP-induced behavioral symptoms, improved motor coordination, and protected against dopaminergic neuron loss and the activation of astrocytes and microglia in the substantia nigra. The protective effects of nicotine were abolished by administration of the α7-nAChR-selective antagonist methyllycaconitine (MLA). In primary cultured mouse astrocytes, pretreatment with nicotine suppressed MPP(+)-induced or LPS-induced astrocyte activation, as evidenced by both decreased production of TNF-α and inhibition of extracellular regulated kinase1/2 (Erk1/2) and p38 activation in astrocytes, and these effects were also reversed by MLA. Taken together, our results suggest that α7-nAChR-mediated inhibition of astrocyte activation is an important mechanism underlying the protective effects of nicotine.
  Journal of Neuroinflammation 05/2012; 9:98. · 3.83 Impact Factor
• Article: Dynamic alterations of gene expression of nicotinic acetylcholine receptor α7, α4 and β2 subunits in an acute MPTP-lesioned mouse model.

  Jun Hu, Chenlei Zhu, Yuan Liu, Fang Wang, Zuhu Huang, Weimin Fan, Jie Wu
  [show abstract] [hide abstract]
  ABSTRACT: Epidemiologic studies show that the prevalence of Parkinson's disease (PD) is lower in smokers than in nonsmokers. Nicotine, a potent agonist of nicotinic acetylcholine receptors (nAChRs), excites midbrain dopaminergic neurons and this may contribute to the anti-parkinsonian effects. However, the alterations in gene expression of nAChR subunits using an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse PD model remain unclear. In the present study, we profile the time course of nAChR α7, α4 and β2 subunit expression levels using a comparative RT-PCR approach after acute MPTP injection. The results fall into four categories. (1) MPTP treatment transiently increased nAChR α7 (after last injection of MPTP 3 and 24 h), α4 and β2 (24 h) mRNA expression in the substantia nigra (SN) and striatum. (2) Compared to cortical and hippocampal tissues, this transient increase of nAChR subunit expression specifically occurred in the SN and striatum. (3) In the acute MPTP model, time-courses of altered expression for nAChR α7, α4 and β2 subunits closely mirrored the deficits observed in animal motor activity. (4) Stereological data showed that after administration of MPTP for 24h, there was a robust astrogliosis in the SN associated with significant dopaminergic neurodegeneration. These changes followed or paralleled MPTP-induced elevation in the levels of α7, α4 and β2 mRNAs. Collectively, our results demonstrate that nAChRs are important targets in the MPTP neurotoxic process. These data suggest that therapeutic strategies targeted toward nAChR α7, α4 and β2 subunits may have potential for developing new treatments for PD.
  Neuroscience Letters 03/2011; 494(3):232-6. · 2.11 Impact Factor