Background
Epigenetic studies, particularly research on microRNA (miRNA), have flourished. The abnormal expression of miRNA contributes to the development of hematologic malignancies. miR-765 has been reported to inhibit cell proliferation by downregulating proteolipid protein 2 (PLP2), which causes apoptosis. We investigated miR-765 dysregulation in myelodysplastic syndromes (MDS).
Methods
We compared the expression profiles of miR-765 in 65 patients with MDS and 11 controls. Cell proliferation and apoptosis assays were performed to determine the in vitro effects of miR-765 on leukemia cells transfected with the miR-765 mimic. Reverse transcription quantitative PCR (RT-qPCR) and western blotting were performed to examine the targets of miR-765.
Results
We found that miR-765 levels were upregulated 10.2-fold in patients with MDS compared to controls. In refractory cytopenia with multilineage dysplasia, the percentage of patients with elevated miR-765 levels was significantly higher than in other forms of MDS. Experiments with leukemia cells revealed that transfection with a miR-765 mimic inhibited cell proliferation and induced apoptosis. RT-qPCR and western blotting demonstrated that the target of miR-765 was PLP2.
Conclusion
These findings imply that upregulation of miR-765 induces apoptosis via downregulation of PLP2 and may have a role in MDS pathogenesis.

Keywords: MDS, microRNA, Deregulation, Apoptosis, Pathogenesis