A Molecular Mechanism for Ibuprofen-Mediated RhoA Inhibition in Neurons

作者:Dill John; Patel Ankur R; Yang Xiao Li; Bachoo Robert; Powell Craig M; Li Shuxin*
来源:Journal of Neuroscience, 2010, 30(3): 963-972.
DOI:10.1523/JNEUROSCI.5045-09.2010

摘要

Ibuprofen is a nonsteroidal anti-inflammatory drug widely used to relieve pain and inflammation in many disorders via inhibition of cyclooxygenases. Recently, we have demonstrated that ibuprofen inhibits intracellular signaling of RhoA and promotes significant axonal growth and functional recovery following spinal cord lesions in rodents. In addition, another study suggests that ibuprofen reduces generation of amyloid-beta 42 peptide via inactivation of RhoA signaling, although it may also regulate amyloid-beta 42 formation by direct inhibition of the gamma-secretase complex. The molecular mechanisms by which ibuprofen inhibits the RhoA signal in neurons, however, remain unclear. Here, we report that the transcription factor peroxisome proliferator-activated receptor gamma (PPAR gamma) is essential for coupling ibuprofen to RhoA inhibition and subsequent neurite growth promotion in neurons. Ibuprofen activates PPAR gamma in neuron-like PC12 and B104 cells. Activation of PPAR gamma with traditional agonists mimics the RhoA-inhibiting properties of ibuprofen in PC12 cells and, like ibuprofen, promotes neurite elongation in primary cultured neurons exposed to axonal growth inhibitors. Protein knockdown with small interfering RNA specific for PPAR gamma blocks RhoA suppression of PPAR gamma agonists in PC12 cells. Moreover, the effect of ibuprofen on RhoA activity and neurite growth in neuronal cultures is prevented by selective PPAR gamma inhibition. These findings support that PPAR gamma plays an essential role in mediating the RhoA-inhibiting effect of ibuprofen. Elucidation of the novel molecular mechanisms linking ibuprofen to RhoA inhibition may provide additional therapeutic targets to the disorders characterized by RhoA activation, including spinal cord injuries and Alzheimer's disease.

  • 出版日期2010-1-20