Recombinant High-Mobility Group Box 1 (rHMGB1) Promotes NRF2-Independent Mitochondrial Fusion through CXCR4/PSMB5-Mediated Drp1 Degradation in Endothelial Cells

Figure 4

Blocking CXCR4 reversed rHMGB1-induced downregulation of Drp1 and mitochondrial fusion. (a–d) Representative immunoblotting bands of Drp1 of cells pretreated with C29, TAK-242, FPS-ZM1, and AMD3100 and the matching internal standard GAPDH. (e–h) The densitometric analysis of relative Drp1 expression of cells pretreated with C29, TAK-242, FPS-ZM1, and AMD3100 referenced to respective matching GAPDH. (i) The representative TEM images of mitochondrial morphology of cells preexposed to TAK-242, AMD3100, and subsequent rHMGB1. (j) The average mitochondrial area (μm²) changes under TEM of cells preexposed to TAK-242, AMD3100, and subsequent rHMGB1. (k) The mitochondrial number changes under TEM in cells preexposed to TAK-242, AMD3100, and subsequent rHMGB1. (l) Mitochondrial morphology of cells preexposed to C29, TAK-242, FPS-ZM1, AMD3100, and subsequent rHMGB1. Cells were subjected to fluorescent staining with MitoTracker Green FM and observed by a Leica SP8 confocal laser scanning microscope. Scale bar: 10 μm. GAPDH: glyceraldehyde-3-phosphate dehydrogenase; TEM: transmission electron microscopy. Data were expressed as the . For comparison of the average mitochondrial area, at least 30 mitochondria of 10 cells per group were calculated; for comparison of mitochondrial number, at least 10 cells per group were counted. , , , and .

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