p38 mitogen-activated protein kinase and calcium channels mediate signaling in depolarization-induced activation of peroxisome proliferator-activated receptor gamma coactivator-1alpha in neurons.
Peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha) coactivates a number of transcription factors critical for mitochondrial biogenesis. Previously, we found that the expression of PGC-1alpha is governed by neuronal activity, but the signaling mechanism is poorly understood. The present study aimed at testing our hypothesis that depolarizing activation of PGC-1alpha in neurons is mediated by p38 mitogen-activated protein kinase (MAPK) and calcium channels. Cultured primary neurons and N2a cells were depolarized with 20 mM KCl for varying times, and increases in PGC-1alpha mRNA and protein levels were found after 0.5 and 1 hr of stimulation, respectively. These levels returned to those of controls after the withdrawal of KCl. Significantly, 15 min of KCl stimulation induced an up-regulation of both p38 MAPK and phosphorylated p38 MAPK that were suppressed by 30 min of pretreatment with SB203580, a blocker of p38 MAPK that also blocked the up-regulation of PGC-1alpha by KCl. Likewise, 30 min of pretreatment with nifedipine, a calcium channel blocker, also prevented the up-regulation of PGC-1alpha mRNA and proteins by KCl. Furthermore, a knockdown of p38 MAPK with small interference hairpin RNA significantly suppressed PGC-1alpha mRNA and protein levels. Our results indicate that both p38 MAPK and calcium play important roles in mediating signaling in depolarization-induced activation of PGC-1alpha at the protein and message levels in neurons.
Liang
Huan Ling
HL
Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
Dhar
Shilpa S
SS
Wong-Riley
Margaret T T
MT
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D010766:Phosphorylation / Q000187:drug effects; D011189:Potassium Chloride / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects; D014793:Visual Cortex / Q000187:drug effects / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D015220:Calcium Channels; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; C501429:Ppargc1a protein, rat; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D011189:Potassium Chloride; D048051:p38 Mitogen-Activated Protein Kinases