Figure 5. FGF21-KLB signaling is dysregulated in ALS motor neurons.

(A) FGF21 were measured in iPSC-derived motor neurons obtained from healthy controls and ALS patients carrying either C9orf72 or SOD1 mutations (Supplementary Table 1). *P = 0.012; two-tailed Mann Whitney test. (B) KLB mRNA levels were similarly measured in iPSC motor neurons. *P = 0.018; two-tailed Mann Whitney test. (C) NSC-34 motor neuron-like cells were transfected with FLAG-tagged WT and SOD1^G93A expression plasmids and lysates were assessed by western blot using the antibodies indicated. Bands were quantitated by densitometry and a ratio to the loading control, vinculin, was calculated (shown between the two blots). (D) KLB and (E) FGF21 mRNA levels were measured in the same lysates. *P = 0.018, ***P = 0.0002, unpaired two-tailed t-test. (F) FGF21 protein was measured in the CM of transfected NSC-34 cells. (G) FGF21 or (H) KLB mRNA levels were quantified from NSC-34 cells exposed to methionine-cystine (MetCys)-deprived media or treated with 100μM H₂O₂ for 24 h. *P = 0.048, ****P < 0.0001; one-way ANOVA followed by Tukey’s multiple comparisons test. Data points represent biological replicates and bars are the mean ± SD.