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Autophagy prevents irradiation injury and maintains stemness through decreasing ROS generation in mesenchymal stem cells.

Hou J, Han ZP, Jing YY, Yang X, Zhang SS, Sun K, Hao C, Meng Y, Yu FH, Liu XQ, Shi YF, Wu MC, Zhang L, Wei LX - Cell Death Dis (2013)

Bottom Line: Stem cells were characterized by their stemness: self-renewal and pluripotency.Autophagy induced by starvation or rapamycin can reduce ROS accumulation-associated DNA damage and maintain stemness in MSCs.Further, inhibition of autophagy leads to augment of ROS accumulation and DNA damage, which results in the loss of stemness in MSCs.

View Article: PubMed Central - PubMed

Affiliation: 1] Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Surgery Hospital, the Second Military Medical University, Shanghai, China [2] Department of Pharmacy, Changhai Hospital, The Second Military Medical University, Shanghai, China.

ABSTRACT
Stem cells were characterized by their stemness: self-renewal and pluripotency. Mesenchymal stem cells (MSCs) are a unique type of adult stem cells that have been proven to be involved in tissue repair, immunoloregulation and tumorigenesis. Irradiation is a well-known factor that leads to functional obstacle in stem cells. However, the mechanism of stemness maintenance in human MSCs exposed to irradiation remains unknown. We demonstrated that irradiation could induce reactive oxygen species (ROS) accumulation that resulted in DNA damage and stemness injury in MSCs. Autophagy induced by starvation or rapamycin can reduce ROS accumulation-associated DNA damage and maintain stemness in MSCs. Further, inhibition of autophagy leads to augment of ROS accumulation and DNA damage, which results in the loss of stemness in MSCs. Our results indicate that autophagy may have an important role in protecting stemness of MSCs from irradiation injury.

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Related in: MedlinePlus

Examination of autophagy in MSCs pretreated with starvation or rapamycin exposed to irradiation. (a) Total protein extracts were analyzed by western blotting with antibody against LC3. GAPDH expression was used as control. (b) Electron micrographs exhibited numerous vacuoles with cytoplasmic content in irradiated MSCs pretreated with starvation or rapamycin; most of them were clearly identified as being autophagosomes. Scale bar: 2 μm
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fig3: Examination of autophagy in MSCs pretreated with starvation or rapamycin exposed to irradiation. (a) Total protein extracts were analyzed by western blotting with antibody against LC3. GAPDH expression was used as control. (b) Electron micrographs exhibited numerous vacuoles with cytoplasmic content in irradiated MSCs pretreated with starvation or rapamycin; most of them were clearly identified as being autophagosomes. Scale bar: 2 μm

Mentions: Subsequently, we investigated the autophagy in irradiated MSCs pretreated with starvation or rapamycin, a well-described inducer of autophagy. Microtubule-associated protein light chain 3 (LC3) expression is the most commonly used marker for autophagosome formation. Autophagy induction leading to LC3 is cleaved to produce LC3-I, which is localized on the membrane of autophagosomes. LC3-II is a lipidated form of LC3-I. We examined the expression of LC3-I (18 kDa) and LC3-II (16 kDa) in MSCs after irradiation by western blotting. The level of LC3-II increased slightly in irradiated MSCs and in rapamycin-pretreated groups. Meanwhile, the amount of LC3-II increased significantly in the irradiated MSCs pretreated with starvation than that in the control group (Figure 3a). Electron microscopic analysis was employed to observe autophagsome formation. The results showed the presence of characteristic double-membrane organelles in irradiated MSCs pretreated with starvation or rapamycin (Figure 3b). All of these results suggested that starvation or rapamycin induces autophagy in irradiated MSCs.


Autophagy prevents irradiation injury and maintains stemness through decreasing ROS generation in mesenchymal stem cells.

Hou J, Han ZP, Jing YY, Yang X, Zhang SS, Sun K, Hao C, Meng Y, Yu FH, Liu XQ, Shi YF, Wu MC, Zhang L, Wei LX - Cell Death Dis (2013)

Examination of autophagy in MSCs pretreated with starvation or rapamycin exposed to irradiation. (a) Total protein extracts were analyzed by western blotting with antibody against LC3. GAPDH expression was used as control. (b) Electron micrographs exhibited numerous vacuoles with cytoplasmic content in irradiated MSCs pretreated with starvation or rapamycin; most of them were clearly identified as being autophagosomes. Scale bar: 2 μm
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3824648&req=5

fig3: Examination of autophagy in MSCs pretreated with starvation or rapamycin exposed to irradiation. (a) Total protein extracts were analyzed by western blotting with antibody against LC3. GAPDH expression was used as control. (b) Electron micrographs exhibited numerous vacuoles with cytoplasmic content in irradiated MSCs pretreated with starvation or rapamycin; most of them were clearly identified as being autophagosomes. Scale bar: 2 μm
Mentions: Subsequently, we investigated the autophagy in irradiated MSCs pretreated with starvation or rapamycin, a well-described inducer of autophagy. Microtubule-associated protein light chain 3 (LC3) expression is the most commonly used marker for autophagosome formation. Autophagy induction leading to LC3 is cleaved to produce LC3-I, which is localized on the membrane of autophagosomes. LC3-II is a lipidated form of LC3-I. We examined the expression of LC3-I (18 kDa) and LC3-II (16 kDa) in MSCs after irradiation by western blotting. The level of LC3-II increased slightly in irradiated MSCs and in rapamycin-pretreated groups. Meanwhile, the amount of LC3-II increased significantly in the irradiated MSCs pretreated with starvation than that in the control group (Figure 3a). Electron microscopic analysis was employed to observe autophagsome formation. The results showed the presence of characteristic double-membrane organelles in irradiated MSCs pretreated with starvation or rapamycin (Figure 3b). All of these results suggested that starvation or rapamycin induces autophagy in irradiated MSCs.

Bottom Line: Stem cells were characterized by their stemness: self-renewal and pluripotency.Autophagy induced by starvation or rapamycin can reduce ROS accumulation-associated DNA damage and maintain stemness in MSCs.Further, inhibition of autophagy leads to augment of ROS accumulation and DNA damage, which results in the loss of stemness in MSCs.

View Article: PubMed Central - PubMed

Affiliation: 1] Tumor Immunology and Gene Therapy Center, Eastern Hepatobiliary Surgery Hospital, the Second Military Medical University, Shanghai, China [2] Department of Pharmacy, Changhai Hospital, The Second Military Medical University, Shanghai, China.

ABSTRACT
Stem cells were characterized by their stemness: self-renewal and pluripotency. Mesenchymal stem cells (MSCs) are a unique type of adult stem cells that have been proven to be involved in tissue repair, immunoloregulation and tumorigenesis. Irradiation is a well-known factor that leads to functional obstacle in stem cells. However, the mechanism of stemness maintenance in human MSCs exposed to irradiation remains unknown. We demonstrated that irradiation could induce reactive oxygen species (ROS) accumulation that resulted in DNA damage and stemness injury in MSCs. Autophagy induced by starvation or rapamycin can reduce ROS accumulation-associated DNA damage and maintain stemness in MSCs. Further, inhibition of autophagy leads to augment of ROS accumulation and DNA damage, which results in the loss of stemness in MSCs. Our results indicate that autophagy may have an important role in protecting stemness of MSCs from irradiation injury.

Show MeSH
Related in: MedlinePlus