IL-38 inhibits osteoporosis via regulating PI3K/Akt/GSK3β/NFATc1 signaling pathway / 中国免疫学杂志

ABSTRACT

Objective:To investigate the role and mechanism of IL-38 in inhibiting osteoporosis.Methods:A total of 138 cases of patients with osteoporosis in our hospital from June 2014 to December 2016 were recruited.Another 120 cases of fracture surgery patients without osteoporosis were selected as control.Serum levels of IL-38 in different groups were determined using a commercially available sandwich ELISA (Enzyme-Linked ImmunoSorbent Assay).Construction of IL-38-C57BL/6J transgenic mice,the wild type and IL-38 transgenic mice were set to sham operation group (Sham),operation group (ovariectomy,group OVX) respectively.After 8 weeks of the operation,the serum level of alkaline phosphatase(ALP),calcium and phosphorus were detected.The bilateral femur and spine of mice were collected after sacrifice,the morphology and structure of the femur were analyzed,and the bone density was measured by bone density meter.The bone marrow stromal cells(BMSCs) were isolated and the invitro proliferation ability of BMSCs were meas-ured.Western blot were used to detect the phosphorylation level of PI3K,Akt,GSK3β and NFATc1 in BMSCs.After transfection of IL-38 into mouse osteoblast MC3T3-E1 cell,the phosphorylation level of PI3K,Akt,GSK3β and NFATc1 were detected by Western blot.Apoptosis of MC3T3-E1 cells were detected by flow cytometry.Results:The serum level of IL-38 in patients with osteoporosis were significant lower than control group(P<0.05).The serum level of estrogen,calcium and phosphorus in OVX group of wild type and IL-38 transgenic mice were significant lower than the sham operation group(P<0.05),while the level of ALP was significant higher than sham operation group (P<0.05),but the serum level of calcium and phosphorus in OVX group of IL-38 transgenic mice were significant higher than wild type mice(P<0.05).The pathological section of femur and spine BMD showed that the bone tissue in wild type mice and IL-38 transgenic mice in OVX group were damaged and the bone density decreased significantly,but IL-38 transgenic mice was significant better than wild type mice (P<0.05).The proliferation ability of BMSCs in OVX group of IL-38 transgenic mice was significant higher than wild type mice (P<0.05).The phosphorylation level of PI3K,Akt and NFATc1 in OVX group of IL-38 transgenic mice were significant lower than wild type mice(P<0.05),while the phosphorylation level of GSK3β was significant higher than wild type mice (P<0.05).After transfection of IL-38 into MC3T3-E1 cell,the phosphorylation level of PI3K,Akt and NFATc1 were significant decreased (P<0.05),while the phosphorylation level of GSK3β was significant increased (P<0.05).Flow cytometry assay showed that IL-38 transfection significant decreased the apoptosis of MC3T3-E1 cells(P<0.05).Conclusion:The serum level of IL-38 in patients with osteoporosis is decreased significantly.IL-38 may inhibit the proliferation of BMSCs and inhibit the apoptosis of osteoblasts by regulating the PI3K/Akt/GSK3β/NFATc1 signaling pathway.