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ATM mediates spermidine-induced mitophagy via PINK1 and Parkin regulation in human fibroblasts.

Qi Y, Qiu Q, Gu X, Tian Y, Zhang Y - Sci Rep (2016)

Bottom Line: Our results indicate that spermidine induces mitophagy by eliciting mitochondrial depolarization, which triggers the formation of mitophagosomes and mitolysosomes, thereby promoting the accumulation of PINK1 and translocation of Parkin to damaged mitochondria, finally leading to the decreased mitochondrial mass in GM00637 cells.These results suggest that ATM drives the initiation of the mitophagic cascade.These findings underscore the importance of a mitophagy regulatory network of ATM and PINK1/Parkin and elucidate a novel mechanism by which ATM influences spermidine-induced mitophagy.

View Article: PubMed Central - PubMed

Affiliation: Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.

ABSTRACT
The ATM (ataxia telangiectasia mutated) protein has recently been proposed to play critical roles in the response to mitochondrial dysfunction by initiating mitophagy. Here, we have used ATM-proficient GM00637 cells and ATM-deficient GM05849 cells to investigate the mitophagic effect of spermidine and to elucidate the role of ATM in spermdine-induced mitophagy. Our results indicate that spermidine induces mitophagy by eliciting mitochondrial depolarization, which triggers the formation of mitophagosomes and mitolysosomes, thereby promoting the accumulation of PINK1 and translocation of Parkin to damaged mitochondria, finally leading to the decreased mitochondrial mass in GM00637 cells. However, in GM05849 cells or GM00637 cells pretreated with the ATM kinase inhibitor KU55933, the expression of full-length PINK1 and the translocation of Parkin are blocked, and the colocalization of Parkin with either LC3 or PINK1 is disrupted. These results suggest that ATM drives the initiation of the mitophagic cascade. Our study demonstrates that spermidine induces mitophagy through ATM-dependent activation of the PINK1/Parkin pathway. These findings underscore the importance of a mitophagy regulatory network of ATM and PINK1/Parkin and elucidate a novel mechanism by which ATM influences spermidine-induced mitophagy.

No MeSH data available.


Related in: MedlinePlus

ATM is activated by spermidine in GM00637 cells.GM00637 cells with or without KU55933 pretreatment (a,b), and GM05849 cells (c) were exposed to 50 μM spermidine or CCCP, followed by immunofluorescence analyses of total and p-ATM on Ser-1981. The scale bar is 10 μm. Ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were presented (d). 20–45 cells/condition from three experiments were collected. Values are mean ± SD, *p < 0.05 vs. control.
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f4: ATM is activated by spermidine in GM00637 cells.GM00637 cells with or without KU55933 pretreatment (a,b), and GM05849 cells (c) were exposed to 50 μM spermidine or CCCP, followed by immunofluorescence analyses of total and p-ATM on Ser-1981. The scale bar is 10 μm. Ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were presented (d). 20–45 cells/condition from three experiments were collected. Values are mean ± SD, *p < 0.05 vs. control.

Mentions: Spermidine-induced mitophagy is dependent on ATM and mediated by the PINK1/Parkin pathway. Therefore, it is critical to determine how this process is regulated. To confirm the role of ATM in spermidine-induced mitophagy, we first examined the phosphorylation of ATM Ser-1981, a general marker of ATM pathway activation. Immunofluorescence analysis showed that p-ATM Ser-1981 levels increased substantially in both the cytoplasm and the nucleus of GM00637 cells (Fig. 4a). The ATM kinase inhibitor KU55933 greatly attenuated the phosphorylation of ATM Ser-1981 (Fig. 4b). Remarkably, ATM is marginally detectable in GM05849 cells (Fig. 4c). The ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were recorded (Fig. 4d).


ATM mediates spermidine-induced mitophagy via PINK1 and Parkin regulation in human fibroblasts.

Qi Y, Qiu Q, Gu X, Tian Y, Zhang Y - Sci Rep (2016)

ATM is activated by spermidine in GM00637 cells.GM00637 cells with or without KU55933 pretreatment (a,b), and GM05849 cells (c) were exposed to 50 μM spermidine or CCCP, followed by immunofluorescence analyses of total and p-ATM on Ser-1981. The scale bar is 10 μm. Ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were presented (d). 20–45 cells/condition from three experiments were collected. Values are mean ± SD, *p < 0.05 vs. control.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835770&req=5

f4: ATM is activated by spermidine in GM00637 cells.GM00637 cells with or without KU55933 pretreatment (a,b), and GM05849 cells (c) were exposed to 50 μM spermidine or CCCP, followed by immunofluorescence analyses of total and p-ATM on Ser-1981. The scale bar is 10 μm. Ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were presented (d). 20–45 cells/condition from three experiments were collected. Values are mean ± SD, *p < 0.05 vs. control.
Mentions: Spermidine-induced mitophagy is dependent on ATM and mediated by the PINK1/Parkin pathway. Therefore, it is critical to determine how this process is regulated. To confirm the role of ATM in spermidine-induced mitophagy, we first examined the phosphorylation of ATM Ser-1981, a general marker of ATM pathway activation. Immunofluorescence analysis showed that p-ATM Ser-1981 levels increased substantially in both the cytoplasm and the nucleus of GM00637 cells (Fig. 4a). The ATM kinase inhibitor KU55933 greatly attenuated the phosphorylation of ATM Ser-1981 (Fig. 4b). Remarkably, ATM is marginally detectable in GM05849 cells (Fig. 4c). The ratios of cells expressing p-ATM Ser-1981 to cells expressing total ATM were recorded (Fig. 4d).

Bottom Line: Our results indicate that spermidine induces mitophagy by eliciting mitochondrial depolarization, which triggers the formation of mitophagosomes and mitolysosomes, thereby promoting the accumulation of PINK1 and translocation of Parkin to damaged mitochondria, finally leading to the decreased mitochondrial mass in GM00637 cells.These results suggest that ATM drives the initiation of the mitophagic cascade.These findings underscore the importance of a mitophagy regulatory network of ATM and PINK1/Parkin and elucidate a novel mechanism by which ATM influences spermidine-induced mitophagy.

View Article: PubMed Central - PubMed

Affiliation: Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.

ABSTRACT
The ATM (ataxia telangiectasia mutated) protein has recently been proposed to play critical roles in the response to mitochondrial dysfunction by initiating mitophagy. Here, we have used ATM-proficient GM00637 cells and ATM-deficient GM05849 cells to investigate the mitophagic effect of spermidine and to elucidate the role of ATM in spermdine-induced mitophagy. Our results indicate that spermidine induces mitophagy by eliciting mitochondrial depolarization, which triggers the formation of mitophagosomes and mitolysosomes, thereby promoting the accumulation of PINK1 and translocation of Parkin to damaged mitochondria, finally leading to the decreased mitochondrial mass in GM00637 cells. However, in GM05849 cells or GM00637 cells pretreated with the ATM kinase inhibitor KU55933, the expression of full-length PINK1 and the translocation of Parkin are blocked, and the colocalization of Parkin with either LC3 or PINK1 is disrupted. These results suggest that ATM drives the initiation of the mitophagic cascade. Our study demonstrates that spermidine induces mitophagy through ATM-dependent activation of the PINK1/Parkin pathway. These findings underscore the importance of a mitophagy regulatory network of ATM and PINK1/Parkin and elucidate a novel mechanism by which ATM influences spermidine-induced mitophagy.

No MeSH data available.


Related in: MedlinePlus