Using the NF-kB pathway to Determine CTMP Expression Changes for ALS

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the development of progressive muscle paralysis. It is known that a protein important for cell growth and survival, Akt, stops the transcription of specific ligases involved in the degeneration of muscle cells. The reasons why Akt signaling is diminished in muscle tissue in ALS is not clear. Carboxyl-terminal modulator protein (CTMP), which has been previously identified as a negative regulator of Akt, is significantly elevated in atrophied muscle during the final stages of ALS. Tumor Necrosis Factor-α (TNF-α) is an inflammatory molecule associated with muscle atrophy in ALS, and our previous research demonstrated that TNF-α stimulation of mouse muscle cells in cell culture increased CTMP expression. TNF-α also increases cellular nuclear factor kappa beta (NF-kB) activity and nuclear localization. In the present study, we hypothesized that TNF-α-mediated NF-kB activation leads to increased CTMP expression. We tested this hypothesis by treating mouse muscle cells with TNF-α while prohibiting NF-kB activity with a small molecule and examined CTMP expression with Western blot analysis. We found that TNF-α significantly increased NF-kB activity and nuclear localization in mouse muscle cells and that blocking NF-kB activity in TNF-α treated cells reduced CTMP expression.