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. Author manuscript; available in PMC: 2020 Apr 1.
Published in final edited form as: Mol Neurobiol. 2018 Jul 19;56(4):2314–2327. doi: 10.1007/s12035-018-1234-2

Figure 4. Nrf2-Keap1 pathway is involved in the protection effect of FGF21 against HG-IL1β induced endothelial monolayer permeability.

Figure 4.

The involvement of Nrf2 in FGF21 protection for BBB was examined using db/db mice and cultured HBMEC monolayer. (A) Nrf2 and pNrf2 protein levels measured by Western blot in nuclear extract of db/db mice brain after rFGF21 treatment (* p<0.05 vs. db/+; # p<0.05 vs. db/db; n=4); (B) Nrf2 and pNrf2 protein levels measured by Western blot in cultured HBMEC after HG-IL1β and rFGF21 treatment (* p<0.05 vs. norm; # p<0.05 vs. HG-IL1β; n=3). (C) Relative HBMEC monolayer permeability after treatment with HG-IL1β and rFGF21, with or without Trigonelline, the Nrf2 inhibitor (* p<0.05 vs. norm; # p<0.05 vs. HG-IL1β; & p<0.05 vs. HG-IL1β+F21; n=4). The roles of Nrf2-Keap1 interaction in BBB protection by FGF21 was further investigated using db/db mice and cultured HBMEC. (D) Representative Western blot images and quantification for Keap1 protein in db/db mice brain after FGF21 treatment; (E) Representative Western blot images and quantification for Nrf2 and pNrf2 detection after Co-IP with Keap1 antibody using the brain lysate of db/db mice after rFGF21 treatment (* p<0.05 vs. db/+; # p<0.05 vs. db/db; n=4). Keap1 and Nrf2 interaction was also measured in cultured HBMEC after HG-ΙL1β and rFGF21 treatment. (F) Keap1 Western blot and quantification in cultured HBMCE; (G) Co-IP was performed using Keap1 antibody with HBMCE lysate, and pNrf2 in the precipitate was assessed using Western blot (* p<0.05 vs. norm; # p<0.05 vs. HG- IL1β; n=3). (H) Representative Western blot images of Smad2, p-Smad2 and Snail in db/db mice after rFGF21 treatment.