Insulin-Like Growth Factor I Prevents Cellular Aging via Activation of Mitophagy

Figure 3

IGF-1 upregulated mitophagy. P5 and P20 SMC were exposed to 10 ng/ml IGF-1 for 12 h and stained with Mtphagy and Lyso dyes using the Mitophagy Detection Kit (a, b). Mtphagy dye emits a high fluorescence when mitochondria fuse with lysosome, and this signal was detected by 594 nm filter; Lyso dye signal was assessed by 488 nm filter. Overlapping signal of Mtphagy and Lyso dyes (merge) was localized exclusively in the perinuclear region of a cell. A number of vacuoles double-positive for Mtphagy and Lyso was quantified per cell and shown in the graph. P20 cells were treated with IGF-1, or Baf, or with combination of IGF-1 + Baf; mitochondrial fraction was isolated, and mitochondrial LC3 II/I ratio was quantified by immunoblotting/densitometry (c). for untreated P20 vs. untreated P5 SMC. ^# for cells treated with IGF-1 or Baf or combination of IGF-1 and Baf vs. untreated SMC. Empty bars, P5 SMC; solid bars, P20 SMC. Scale bar, 100 μm.

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