Explore the role of AMPK activation in TDP-43 mislocalization and cell death

• Main Authors: Li-Ming Lee, 李俐旻
• Other Authors: Yijuang Chern
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/98471701202633910656

碩士 === 國立陽明大學 === 神經科學研究所 === 102 === Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, the main symptoms are muscle weakness, swollen difficulty and paralysis. The disease causing factors include genetic factors (familial ALS) and environmental factors (sporadic ALS). The common disease-causing genes are superoxide dismutase1 (SOD1), TAR DNA binding protein-43 (TDP-43) and close to 30 newly identified risk genes. The environmental factors are not clear, but there are a common pathological features, TDP-43 mislocalization in brain and spinal cord of ALS patients. Although the importance of TDP-43 in ALS, or in other neurodegenerative diseases had been mentioned, the detailed mechanism of TDP-43 mislocalization in neurodegenerative diseases is unclear. Using Western Blot and Immunocytometry, we found that activation of the AMP-activating protein kinase (AMPK) using an AMPK activator (5-aminoimidazole-4-carboxamide ribonucleoside, AICAR) caused TDP-43 mislocalization in a motor neuron-like cell line (NSC34). Activation of the adenosine 2A receptor (A2AR) prevented and rescued the TDP-43 mislocalization by reducing AMPK activation through the cAMP-dependent protein kinase A (PKA). A combination of AMPK activation and proteasome dysfunction also led to TDP-43 mislocalization in the ES- derived motor neurons. By using Immunohistochemistry, we demonstrated that AMPK activation using AICAR also led to TDP-43 mislcoalization in mice. Using the MTT assay, we found that AMPK activation induced by AICAR also led to decreased cell viability in NSC34 cells, while activating A2AR prevented the AMPK- mediated decrease of cell viability. However activating A2AR after AMPK activation evoked by AICAR did not restore cell viability decrease. Using Immunocytometry, we found that AMPK activation led to nuclear fragmentation in the ES- derived motor neurons, which is a feature during cell apoptosis. And by using Immunohistochemistry, we showed that the number of motor neurons decreased in a TDP-43 transgenic mice. Collectively, we found that AMPK activation may be an important factor implicated in both TDP-43 mislocalization and cell death in vitro and in vivo. In a motor neuron cell line model (NSC34), we found that activating A2AR prevented and rescued the AMPK- mediated TDP-43 mislocalization. These findings help us to have a closer look into the mechanism of TDP-43 mislocalization and the disease- causing factors.