Alterations in STriatal-Enriched protein tyrosine Phosphatase expression, activation, and downstream signaling in early and late stages of the YAC128 Huntington's disease mouse model
| Autor: | Jing Fan, Edward H. Y. Li, Clare M. Gladding, Liang Wang, Lily Y. J. Zhang, Paul J. Lombroso, Jian Xu, Lynn A. Raymond |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Huntingtin Excitotoxicity Apoptosis Mice Transgenic Protein tyrosine phosphatase medicine.disease_cause Biochemistry Gene Expression Regulation Enzymologic Article Mice 03 medical and health sciences Cellular and Molecular Neuroscience Organ Culture Techniques 0302 clinical medicine medicine Animals Humans Protein kinase A Chromosomes Artificial Yeast 030304 developmental biology 0303 health sciences biology Neurodegeneration Calpain Protein Tyrosine Phosphatases Non-Receptor medicine.disease Molecular biology Corpus Striatum Enzyme Activation Disease Models Animal Huntington Disease nervous system biology.protein Phosphorylation Signal transduction 030217 neurology & neurosurgery Signal Transduction |
| Zdroj: | Journal of Neurochemistry. 130:145-159 |
| ISSN: | 0022-3042 |
| DOI: | 10.1111/jnc.12700 |
| Popis: | Striatal neurodegeneration and synaptic dysfunction in Huntington's disease are mediated by the mutant huntingtin (mHtt) protein. MHtt disrupts calcium homeostasis and facilitates excitotoxicity, in part by altering NMDA receptor (NMDAR) trafficking and function. Pre-symptomatic (excitotoxin-sensitive) transgenic mice expressing full-length human mHtt with 128 polyglutamine repeats (YAC128 Huntington's disease mice) show increased calpain activity and extrasynaptic NMDAR (Ex-NMDAR) localization and signaling. Furthermore, Ex-NMDAR stimulation facilitates excitotoxicity in wild-type cortical neurons via calpain-mediated cleavage of STriatal-Enriched protein tyrosine Phosphatase 61 (STEP61). The cleavage product, STEP33, cannot dephosphorylate p38 mitogen-activated protein kinase (MAPK), thereby augmenting apoptotic signaling. Here, we show elevated extrasynaptic calpain-mediated cleavage of STEP61 and p38 phosphorylation, as well as STEP61 inactivation and reduced extracellular signal-regulated protein kinase 1/2 phosphorylation (ERK1/2) in the striatum of 6-week-old, excitotoxin-sensitive YAC128 mice. Calpain inhibition reduced basal and NMDA-induced STEP61 cleavage. However, basal p38 phosphorylation was normalized by a peptide disrupting NMDAR-post-synaptic density protein-95 (PSD-95) binding but not by calpain inhibition. In 1-year-old excitotoxin-resistant YAC128 mice, STEP33 levels were not elevated, but STEP61 inactivation and p38 and ERK 1/2 phosphorylation levels were increased. These results show that in YAC128 striatal tissue, enhanced NMDAR-PSD-95 interactions contributes to elevated p38 signaling in early, excitotoxin-sensitive stages, and suggest that STEP61 inactivation enhances MAPK signaling at late, excitotoxin-resistant stages. The YAC128 Huntington's disease mouse model shows early, enhanced susceptibility to NMDA receptor-mediated striatal apoptosis, progressing to late-stage excitotoxicity resistance. This study shows that elevated NMDA receptor-PSD-95 interactions as well as decreased extrasynaptic STriatal-Enriched protein tyrosine Phosphatase 61 (STEP61) activation may contribute to early enhanced apoptotic signaling. In late-stage YAC128 mice, reduced STEP61 levels and activity correlate with elevated MAPK signaling, consistent with excitotoxicity resistance. Solid and dotted arrows indicate conclusions drawn from the current study and other literature, respectively. |
| Databáze: | OpenAIRE |
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