Fig. 5.

Mutant SOD1 causes biochemical alteration of TDP-43 in NSC-34 cells and primary cortical neurons. a NSC-34 cells were transfected with wild-type (WT) SOD1 or mutant (MT) SOD1, and the change in TDP-43 (C-terminal) protein was examined using immunoblotting. MTSOD1 transfected cells had significantly higher level of TDP-35 and TDP-25. b Western blots with anti-GFP or anti-TDP-43 showing reciprocal co-immunoprecipitation of SOD1 (anti-V5). We found that SOD1-TDP-43 interactions were significantly increased in MTSOD1 transfected cells. c SOD1 small interfering RNA (siRNAs) downregulated the levels of TDP-43, TDP-35, and TDP-25 in MTSOD1 transfected NSC-34 cells. d NSC-34 cells were co-transfected with flag-TDP-43, flag-TDP-35, and flag-TDP-25 or V5-WTSOD1 or V5-MTSOD1. Co-transfection with V5-MTSOD1 and flag-TDP-43, flag-TDP-35, or flag-TDP-25 additively increased cleaved caspase-3 levels at 48 h after transfection. e WT and G93A-SOD1 mice primary cortical neurons in DIV10 were transfected with GFP or GFP-TDP-43, its fragments GFP-TDP-35 or GFP-TDP-25 for 48 h. TDP-43, TDP-35, and TDP-25 increased G93A-SOD1 mice primary neuronal cell death. Values are mean ± SEM, n = 4; *P < 0.05, **P < 0.01, *** P < 0.001