Inhibition of Mitofusin-2 Promotes Cardiac Fibroblast Activation via the PERK/ATF4 Pathway and Reactive Oxygen Species

Figure 4

Mfn2 modulated ER stress through repression of the PERK/ATF4 pathway in activated cardiac fibroblasts. (a) Protein expressions of p-PERK, ATF4, p-IRE1α, Xbp1s, and c-ATF6 with TGF-β1 treatment in cardiac fibroblasts (); (b) protein expressions of p-PERK, ATF4, p-IRE1α, Xbp1s, and c-ATF6 in cardiac fibroblasts with siMfn2 transfection in the presence or absence of TGF-β1 (); (c) protein expressions of p-PERK, ATF4, p-IRE1α, Xbp1s, and c-ATF6 in cardiac fibroblasts with overexpression adenovirus transduction in the presence or absence of TGF-β1 (); (d) the protein level of the ER stress branch, the PERK/ATF4 pathway, after siMfn2 transfection (); siMfn2 transfection in the presence or absence of 4-PBA; (e) the protein levels of α-SMA, TGF-β, and CTGF in cardiac fibroblasts after transfection with siMfn2 (); siMfn2 transfection in the presence or absence of 4-PBA; (f) the proliferation rate of cardiac fibroblasts (the red fluorescence indicated EdU-incorporated cells and the blue fluorescence indicated the cell nucleus stained by DAPI, ) after transfection with siMfn2; siMfn2 transfection in the presence or absence of 4-PBA; (g) the protein level of the ER stress branch, the PERK/ATF4 pathway, after overexpression adenovirus transduction (); adenovirus transduction in the presence or absence of thapsigargin; (h) the protein levels of α-SMA, TGF-β, and CTGF in cardiac fibroblasts after transduction with overexpression adenovirus (); overexpression adenovirus transduction in the presence or absence of thapsigargin; (i) the proliferation rate of cardiac fibroblasts (the red fluorescence indicated EdU-incorporated cells and the blue fluorescence indicated the cell nucleus stained by DAPI, ) after transduction with adenovirus; overexpression adenovirus transduction in the presence or absence of thapsigargin; (j) protein expression of ATF4 with siMfn2 transfection followed with siATF4 transfection in the presence or absence of TGF-β1 in cardiac fibroblasts; (k) the protein levels of α-SMA, TGF-β, and CTGF in cardiac fibroblasts after siMfn2 transfection followed with siATF4 transfection in the presence or absence of TGF-β1 in cardiac fibroblasts; data in (a–k) are expressed as . indicates , indicates , and indicates vs. the NC or siMfn2 groups.

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