Figure 4.

Distinct changes of human α-Pal^NRF1 and TFAM in HepG2-derived hNfe2l1α^−/− and hNfe2l2^−/− cell lines. (a) Distinct protein levels of human Nfe2l1, Nfe2l2, α-Pal^NRF1, and TFAM as well as other relevant proteins were determined by Western blotting of hNfe2l1α^−/−, hNfe2l2^−/−, and wild-type HepG2 cells. (b) Basal mRNA expression levels of Nfe2l1, Nfe2l2, α-Pal^NRF1, TFAM, and other indicated genes were examined by real-time qPCR of hNfe2l1α^−/−, hNfe2l2^−/−, and wild-type HepG2 cells. The resultant data are shown as mean ± SEM (n = 3 × 3) with significant decreases (^∗p < 0.01, ^∗∗p < 0.001) or significant increases ($, p < 0.01; $$, p < 0.001). (c) The FPKM (Reads Per Kilobase per Million mapped reads) value of Nfe2l1, Nfe2l2, α-Pal^NRF1, TFAM, and other indicated genes were obtained by RNA-sequencing of hNfe2l1α^−/−, hNfe2l2^−/−, hNfe2l1α^−/−+siNfe2l2, and hNfe2l1/2^+/+. (d) Different protein levels of Nfe2l1, α-Pal^NRF1, and TFAM were examined in HepG2 cells that had been transfected with an hNfe2l1 expression construct or empty pcDNA3.1. (e) Distinct inducible alterations in abundances of Nfe2l1, Nfe2l2, α-Pal^NRF1, TFAM, HO-1, GCLM, and SOD1 were determined by Western blotting of hNfe2l1α^+/+ or hNfe2l1α^−/− that had been or not been treated with 50μmol/L tBHQ. (f, g) Distinct inducible mRNA levels of Nfe2l1, Nfe2l2, α-Pal^NRF1, HO-1, GCLM, TFAM, COX5a, and SOD1 were revealed by real-time qPCR of between tBHQ-stimulated lines of hNfe2l1α^+/+ cells (f) and hNfe2l1α^−/− cells (g). The resultant data are shown as mean ± SEM (n = 3 × 3) with significant increases (^∗p < 0.01, ^∗∗p < 0.001). (h) A model is assumed to present cross-talks between human Nfe2l1 and Nfe2l2, along with distinct effects on human α-Pal^NRF1, TFAM, and other gene expression, particularly upon stimulation by tBHQ.