Analysis on the Effects of PPARγ Gene-silenced Human Bone Marrow Stromal Cells on Hematopoietic Function in Mice with Bone Marrow Suppression / 华中科技大学学报(医学版)

ABSTRACT

Objective To investigate the effects of peroxisome proliferator activated receptor-gamma(PPARγ)gene silen-cing in human bone marrow stromal cells(HS-5)on hematopoietic function in bone marrow-suppressed mice,and to explore the potential mechanisms involved.Methods A bone marrow-suppressed mouse model was established by whole-body X-ray irradi-ation.Two hours after modeling,the mice were randomly divided into three groupsexperimental group(intravenous injection of PPARγ RNAi-interfered HS-5 cells through the tail vein),control group(intravenous injection of PPARγ RNAi-uninterfered HS-5 cells through the tail vein),and blank group(intravenous injection of an equal amount of saline through the tail vein),with 5 mice in each group.Peripheral blood routine tests were performed before,24 hours after,1 week after,and 2 weeks after radio-therapy.In vitro osteogenic and adipogenic induction was performed in cells,and the cells were divided into experimental group(PPARγ RNAi-interfered HS-5 cells),control group(PPARγ-uninterfered HS-5 cells),and blank group(HS-5 cells without os-teogenic/adipogenic induction).Osteogenic/adipogenic staining was observed.The effects of PPARγ gene-silenced HS-5 cells on mouse bone marrow hematopoietic stem cells(HSCs)were detected by CCK-8 proliferation assay.The groups included experi-mental group(PPARγ RNAi-interfered HS-5 cells were co-cultured with mouse HSCs after 3 days of osteogenic induction dif-ferentiation),positive control group(HS-5 cells treated with 50 μmol/L PPARγ inhibitor were co-cultured with mouse HSCs af-ter 3 days of osteogenic induction differentiation),negative control group(PPARγ RNAi-uninterfered HS-5 cells were co-cul-tured with mouse HSCs after 3 days of osteogenic induction differentiation),and blank group(Mouse HSCs were cultured alone without co-culturing with HS-5 cells).Results After radiotherapy,the hematological parameters of mice in each group showed a decreasing trend initially,and then increased.One week after radiotherapy,there were significant differences in platelet and white blood cell levels among the three groups(experimental group＞control group＞blank group,all P＜0.05).Two weeks after radiotherapy,there were significant differences in the percentage of adipocyte vacuole area among the three groups(experi-mental group＜control group＜blank group,all P＜0.05).Pearson correlation analysis showed a negative correlation between hematological parameters and PPARγ expression levels(all P＜0.05),as well as a negative correlation between hematological parameters and the percentage of adipocyte vacuole area(all P＜0.05).After in vitro osteogenic/adipogenic induction differenti-ation,compared to the control group,the experimental group showed a significantly lower proportion of orange-red cells and a significantly higher proportion of red calcium nodules.After 3 days of osteogenic induction differentiation,the experimental group,positive control group,and negative control group of human bone marrow stromal cells were co-cultured with mouse HSCs,while HSCs were solely cultured in the blank group.The results showed that after 24 h,48 h and 72 h of co-culture,the A values of mouse HSC cells in the experimental group and positive control group were higher than those in the negative control group and blank group(all P＜0.05).Conclusion Silencing of the PPARγ gene in HS-5 cells implanted into bone marrow-sup-pressed mice contributes to enhanced hematopoietic function in mice.After interference and silencing of the PPARγ gene,the os-teogenic differentiation ability of HS-5 cells is enhanced,while the adipogenic differentiation ability is weakened.Furthermore,osteogenic-induced HS-5 cells can further enhance the proliferation capacity of mouse HSCs.