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Male-Specific Alleviation of Iron-Induced Striatal Injury by Inhibition of Autophagy.

Wang LF, Yokoyama KK, Chen TY, Hsiao HW, Chiang PC, Hsieh YC, Lo S, Hsu C - PLoS ONE (2015)

Bottom Line: Pre-treatment of FC-infused females with rapamycin increased the FC-induced behavioral deficit and DRD2 neuron death.These results suggest that autophagy in FC-infusion males is overactive with maladaptive consequences and inhibition of autophagy decreases the severity of FC-induced striatal injury in males.These findings present prospects for male-specific therapeutic strategy that targets autophagy in patients suffering from iron overload.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Men exhibit a worse survival rate than premenopausal women after intracerebral hemorrhage (ICH), however, no sex-specific management has been concerned. In a rat model involving infusion of ferrous citrate (FC) that simulates iron accumulation after hemorrhage, a higher degree of autophagy associated with higher injury severity was observed in striatum of males than in females. Since the imbalance between the levels of autophagy and energy demand may lead to cell death, we proposed that FC-induced autophagy is detrimental in a male specific manner and autophagy modulation affects injury severity in a sex-dependent manner. Rapamycin, an autophagy inducer, and conditional knockout gene of autophagy-related protein 7 (Atg7) in dopamine receptor D2 (DRD2) neurons were used to test our hypothesis using a mouse model with striatal FC infusion. The result showed that the levels of autophagic cell death and injury severity were higher in male than in female mice. Pre-treatment of FC-infused females with rapamycin increased the FC-induced behavioral deficit and DRD2 neuron death. However, DRD2 neuron-specific knockout of Atg7 decreased FC-induced injury severity and the number of TUNEL(+) DRD2 neurons in males. These results suggest that autophagy in FC-infusion males is overactive with maladaptive consequences and inhibition of autophagy decreases the severity of FC-induced striatal injury in males. These findings present prospects for male-specific therapeutic strategy that targets autophagy in patients suffering from iron overload.

No MeSH data available.


Related in: MedlinePlus

Rapamycin increased FC-induced DNA fragmentation in the DRD2 neurons of female mice.(A) Representative images of TUNEL(+) DRD2 immunoreactive cells. The images were captured using TissueFAXS. The merged bright yellow dots depict DRD2 neurons with DNA fragmentation, as indicated by the arrows. (B) DRD2 neurons in total cells. (C) TUNEL(+) cells in total nuclei. (D) TUNEL(+) DRD2 neurons in total nuclei. The tissue sections were scanned using a TissueFax cytometer, and the number of TUNEL(+) and/or DRD2 immunoreactive neurons were analyzed by TissueQuest. The data are expressed as the means ± SDs (n = 6). *p<0.05 compared with FC-infusion male; #p<0.05 compared with female mice without rapamycin pre-treatment.
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pone.0131224.g004: Rapamycin increased FC-induced DNA fragmentation in the DRD2 neurons of female mice.(A) Representative images of TUNEL(+) DRD2 immunoreactive cells. The images were captured using TissueFAXS. The merged bright yellow dots depict DRD2 neurons with DNA fragmentation, as indicated by the arrows. (B) DRD2 neurons in total cells. (C) TUNEL(+) cells in total nuclei. (D) TUNEL(+) DRD2 neurons in total nuclei. The tissue sections were scanned using a TissueFax cytometer, and the number of TUNEL(+) and/or DRD2 immunoreactive neurons were analyzed by TissueQuest. The data are expressed as the means ± SDs (n = 6). *p<0.05 compared with FC-infusion male; #p<0.05 compared with female mice without rapamycin pre-treatment.

Mentions: To examine whether the increase in autophagic activity correlates with cell death in neurons, we examined LC3 staining along with neutron marker (NeuN) staining, while the result showed that LC3 immunoreactivity exhibited in both neuron and glial cells and the LC3 antibody reacted with both LC3-I and LC3-II (S2 Fig). Moreover, TUNEL staining along with neutron marker (NeuN) or astrocyte marker (GFAP) staining were performed. The result showed that DNA fragmentation also exhibited in both neuron and astrocyte (S3 Fig). Therefore, we quantified the number of TUNEL positive DRD2 neuron that is more correlative to behavioral deficit due to striatal injury using automated TissueFAXS followed by TissueQuest analysis. The results revealed that FC infusion increased the numbers of TUNEL(+) DRD2 neurons in the striatums of both the male and female mice (Fig 4A). Rapamycin did not change the percentages of DRD2 neurons in the total nuclei of either male or female mice (Fig 4B). Whereas, rapamycin increased the percentages of TUNEL(+) cells and TUNEL(+) DRD2 neurons by 63% and 73%, respectively, in the striatum of the FC infusion female mice but not in males following FC infusion (Fig 4C & 4D).


Male-Specific Alleviation of Iron-Induced Striatal Injury by Inhibition of Autophagy.

Wang LF, Yokoyama KK, Chen TY, Hsiao HW, Chiang PC, Hsieh YC, Lo S, Hsu C - PLoS ONE (2015)

Rapamycin increased FC-induced DNA fragmentation in the DRD2 neurons of female mice.(A) Representative images of TUNEL(+) DRD2 immunoreactive cells. The images were captured using TissueFAXS. The merged bright yellow dots depict DRD2 neurons with DNA fragmentation, as indicated by the arrows. (B) DRD2 neurons in total cells. (C) TUNEL(+) cells in total nuclei. (D) TUNEL(+) DRD2 neurons in total nuclei. The tissue sections were scanned using a TissueFax cytometer, and the number of TUNEL(+) and/or DRD2 immunoreactive neurons were analyzed by TissueQuest. The data are expressed as the means ± SDs (n = 6). *p<0.05 compared with FC-infusion male; #p<0.05 compared with female mice without rapamycin pre-treatment.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492841&req=5

pone.0131224.g004: Rapamycin increased FC-induced DNA fragmentation in the DRD2 neurons of female mice.(A) Representative images of TUNEL(+) DRD2 immunoreactive cells. The images were captured using TissueFAXS. The merged bright yellow dots depict DRD2 neurons with DNA fragmentation, as indicated by the arrows. (B) DRD2 neurons in total cells. (C) TUNEL(+) cells in total nuclei. (D) TUNEL(+) DRD2 neurons in total nuclei. The tissue sections were scanned using a TissueFax cytometer, and the number of TUNEL(+) and/or DRD2 immunoreactive neurons were analyzed by TissueQuest. The data are expressed as the means ± SDs (n = 6). *p<0.05 compared with FC-infusion male; #p<0.05 compared with female mice without rapamycin pre-treatment.
Mentions: To examine whether the increase in autophagic activity correlates with cell death in neurons, we examined LC3 staining along with neutron marker (NeuN) staining, while the result showed that LC3 immunoreactivity exhibited in both neuron and glial cells and the LC3 antibody reacted with both LC3-I and LC3-II (S2 Fig). Moreover, TUNEL staining along with neutron marker (NeuN) or astrocyte marker (GFAP) staining were performed. The result showed that DNA fragmentation also exhibited in both neuron and astrocyte (S3 Fig). Therefore, we quantified the number of TUNEL positive DRD2 neuron that is more correlative to behavioral deficit due to striatal injury using automated TissueFAXS followed by TissueQuest analysis. The results revealed that FC infusion increased the numbers of TUNEL(+) DRD2 neurons in the striatums of both the male and female mice (Fig 4A). Rapamycin did not change the percentages of DRD2 neurons in the total nuclei of either male or female mice (Fig 4B). Whereas, rapamycin increased the percentages of TUNEL(+) cells and TUNEL(+) DRD2 neurons by 63% and 73%, respectively, in the striatum of the FC infusion female mice but not in males following FC infusion (Fig 4C & 4D).

Bottom Line: Pre-treatment of FC-infused females with rapamycin increased the FC-induced behavioral deficit and DRD2 neuron death.These results suggest that autophagy in FC-infusion males is overactive with maladaptive consequences and inhibition of autophagy decreases the severity of FC-induced striatal injury in males.These findings present prospects for male-specific therapeutic strategy that targets autophagy in patients suffering from iron overload.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicinal and Applied Chemistry, College of Life Science, Kaohsiung Medical University, Kaohsiung, Taiwan.

ABSTRACT
Men exhibit a worse survival rate than premenopausal women after intracerebral hemorrhage (ICH), however, no sex-specific management has been concerned. In a rat model involving infusion of ferrous citrate (FC) that simulates iron accumulation after hemorrhage, a higher degree of autophagy associated with higher injury severity was observed in striatum of males than in females. Since the imbalance between the levels of autophagy and energy demand may lead to cell death, we proposed that FC-induced autophagy is detrimental in a male specific manner and autophagy modulation affects injury severity in a sex-dependent manner. Rapamycin, an autophagy inducer, and conditional knockout gene of autophagy-related protein 7 (Atg7) in dopamine receptor D2 (DRD2) neurons were used to test our hypothesis using a mouse model with striatal FC infusion. The result showed that the levels of autophagic cell death and injury severity were higher in male than in female mice. Pre-treatment of FC-infused females with rapamycin increased the FC-induced behavioral deficit and DRD2 neuron death. However, DRD2 neuron-specific knockout of Atg7 decreased FC-induced injury severity and the number of TUNEL(+) DRD2 neurons in males. These results suggest that autophagy in FC-infusion males is overactive with maladaptive consequences and inhibition of autophagy decreases the severity of FC-induced striatal injury in males. These findings present prospects for male-specific therapeutic strategy that targets autophagy in patients suffering from iron overload.

No MeSH data available.


Related in: MedlinePlus