Background

Iron overload could cause the damage of bone morrow mesenchymal stem cells (BMMSCs) through up-regulation of the ROS levels. However, the special mechanism is not fully understood. Many studies have shown that ROS can injure the mitochondrial energy metabolism and lead to the activation of AMP-activated proteins kinase α (AMPKα), which is involved in the mitochondrial fission through enhancing the function of mitochondrial fission factor/dynamin-related protein 1 (MFF/Drp1). In this study, we aim to investigate the role of AMPKα/MFF/Drp1 signaling pathway in the function of BMMSCs from myelodysplastic syndromes (MDS) patients with iron overload.

Methods

Iron overload model was set up with ferric ammonium citrate (FAC) in HS-27a cell line in vitro and BMMSCs were cultivated from MDS patients. Cell apoptosis, cell viability, ROS levels, ATP levels, mitochondrial morphology, cell autophagy, and the activation of electronic respiratory chain complex I/III (ETC I/III) and AMPKα/MFF/Drp1 signaling pathway were analyzed. Additionally, CRISPR/Cas9 AMPKα and MFF shRNA were used to further determine the role of AMPKα/MFF/Drp1 signaling pathway.

Results

We found that iron overload down-regulated the levels of ATP through increasing ROS levels and inhibiting the activation of ETC I/III, then lead to the activation of AMPKα/MFF/Drp1 signaling pathway in HS-27a cells. And as shown in viral experiment, the activation of AMPKα/MFF/Drp1 signaling pathway was involved in the up-regulation of cell apoptosis, mitochondrial fission and cell autophagy, and down-regulation of cell viability in HS-27a cells. More importantly, AMPKα/MFF/Drp1 signaling pathway was also activated in BMMSCs from low risk MDS patients with iron overload, accompanied by ROS levels increased, ETC I/III inhibited, ATP levels inhibited, and cell apoptosis up-regulated, mitochondrial fission enhanced, cell autophagy increased and cell viability weakened. Furthermore, we found that desferrioxamine (DFO) and N-acetyl-L-cysteine (NAC) could improve the cell function caused by iron overload through regulating the AMPKα/MFF/Drp1 signaling pathway in BMMSCs.

Conclusion

AMPKα/MFF/Drp1 signaling pathway may play a key role in the damage of BMMSCs function caused by iron overload in MDS patients.

Disclosures

No relevant conflicts of interest to declare.

Topics:
iron overload, signal pathway, signal transduction pathways, stem cell, mesenchymal, acetylcysteine, citrates, deferoxamine, myelodysplastic syndrome, phosphotransferases, dynamin

Author notes

*

Asterisk with author names denotes non-ASH members.

© 2017 by The American Society of Hematology
2017
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