Autophagy Level Of Bone Marrow Mononuclear Cells Was Abnormal In Patients With Myelodysplastic Syndromes

Background and objectiveTo explore the change of autophagy and its significance in the myelodysplastic syndrome(MDS) patients by detecting the expression level of Beclin 1,mTOR,LC3 in bone marrow mononuclear cells(BMMNC). Materials and methodsThirty-eight patients with MDS and 26 non-malignant anemia patients were enrolled in this study. The iron content of BMMNC was detected by iron stainning. The level of reactive oxygen species(ROS) was detected by flow cytometry. The quantity of autophagic vacuoles were detected by transmission electron microscopy(TEM) and monodansylcadaverine(MDC) staining. The LC3 protein positive cells were cunted by immunofluorescence assays.The expression of Beclin 1,LC3 A,mTOR mRNA were measured by real time PCR.At the same time,the Western blotting was used to analyze the expression of Beclin 1 and LC3 proteins. Results(1) The iron particles appeared more in MDS patients when viewed under a microscope and the intracellular iron content of MDS patients was also higher than that of controls.(2) The ROS level of MDS patients was significantly higher than that of controls(1352.41±667.51 vs.596.46±233.99,P<0.05).(3) The autophgic vacuoles of double membrane that surrounds lysosomes appeared in MDS patients.(4) The percentage of MDC positive cells was significantly higher in MDS patients than that of controls(9.75%±2.63% vs. 2.90%±0.89%, P<0.05).(5) The percentage of LC3 protein cells was also increased in MDS patients(6.13%±1.03% vs. 1.5%±0.58%, P<0.05).(6) The expression of Beclin 1,LC3 A mRNA in low-risk and intermediate-1 MDS were higher compared with controls(3.61±3.02 vs. 1.55±1.03 and 6.56±3.97 vs. 1.21±0.95 respectively,both P < 0.05). The expression of mTOR mRNA was down-regulated in in low-risk and intermediate-1 MDS compared with controls(0.39±0.37 vs. 1.50±1.03, P < 0.05). There were no significant difference in expression of Beclin 1 and mTOR mRNA among the intermediate-2 and high-risk MDS and the controls.(7) The expression of Beclin 1 protein and LC3 B were higher in MDS patients than that of controls. Conclusions:The enhanced autophagy in low-risk and intermediate-1MDS might be considered as a cell protective mechanism. The relatively defective autophagy in intermediate-2 and high-risk MDS might contribute to its progress to AML.