Synergism and Antagonism of Two Distinct, but Confused, Nrf1 Factors in Integral Regulation of the Nuclear-to-Mitochondrial Respiratory and Antioxidant Transcription Networks

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 () with significant decreases (, ) or significant increases ($, ; $$, ). (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 () with significant increases (, ). (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.

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