铁蓄积引起骨量下降与骨髓造血细胞自噬功能改变的研究  

Study on the iron accumulation-induced bone loss and hematopoietic autophagy dysfunction

作　　者：袁晔 方艺璇[3] 刘功稳[4] 高焱 沈光思 刘志鹏[2] 朱柯雨[2] 郑苗 毕擎 赵晨 徐又佳[2,6] Yuan Ye;Fang Yixuan;Liu Gongwen;Gao Yan;Shen Guangsi;Liu Zhipeng;Zhu Keyu;Zheng Miao;Bi Qing;Zhao Chen;Xu Youjia(Department of Orthopaedics,Zhejiang Provincial People′s Hospital,People′s Hospital of Hangzhou Medical College,Hangzhou 310014,China;Department of Orthopaedics,the Second Affiliated Hospital of Soochow University,Suzhou 215004,China;Hematology Center of Cyrus Tang Medical Institute,Soochow University School of Medicine,Suzhou 215123,China;Department of Orthopaedics and Traumatology,Suzhou Hospital of Traditional Chinese Medicine,Suzhou 215009,China;Department of Orthopaedics,Kunshan First People′s Hospital,Kunshan 215300,China;Osteoporosis Clinical Center,the Second Affiliated Hospital of Soochow University,Suzhou 215004,China)

机构地区：[1]浙江省人民医院(杭州医学院附属人民医院)骨科,310014 [2]苏州大学附属第二医院骨科,215004 [3]苏州大学唐仲英医学研究院血液学研究中心,215123 [4]苏州市中医医院骨伤科,215009 [5]昆山市第一人民医院骨科,215300 [6]苏州大学附属第二医院骨质疏松症临床中心,215004

出　　处：《中华内分泌代谢杂志》2021年第5期472-476,共5页Chinese Journal of Endocrinology and Metabolism

基　　金：国家自然科学基金(82072474);江苏省临床医学重点(BE2019661);江苏省研究生科研与实践创新计划项目(KYCX18_2531);浙江省医药卫生科技计划项目(2019327519);浙江省医药卫生科技计划项目(2020373261);浙江省人民医院优秀科研启动基金(ZRY2020B005)。

摘　　要：目的铁蓄积与绝经后骨质疏松症发生相关,髋部骨质疏松骨折存在骨髓造血细胞自噬异常;本研究希望了解铁蓄积导致骨量下降与造血细胞自噬功能之间相关性,探索骨质疏松症新的危险因素。方法使用雄性小鼠腹腔注射枸橼酸铁铵构建铁蓄积小鼠模型,ELISA检测血清铁蛋白和骨生成指标I型前胶原氨基末端肽(P1NP),micro-CT检测股骨骨密度,通过流式细胞仪分析小鼠股骨和胫骨骨髓造血干祖细胞比例和细胞凋亡,流式成像检测骨髓造血干祖细胞自噬溶酶体形成;使用造血细胞条件性敲除Atg7基因小鼠Atg7^(flox/flox);Vav-Cre(本文以Atg^(7-/-)表示)对Atg^(7-/-)小鼠股骨进行micro-CT扫描、股骨和胫骨骨髓造血干祖细胞进行转录组测序。结果两组比较后铁蓄积组显示:血清铁蛋白升高、血清骨生成指标P1NP表达减低、股骨骨密度下降(P<0.05),骨髓造血干祖细胞比例异常升高(P<0.05)且伴随细胞凋亡比例增加(P<0.05),骨髓造血干祖细胞自噬溶酶体形成受抑制;在Atg^(7-/-)小鼠中,骨髓转录组测序结果提示:铁代谢活动增强,铁载体相关基因Lcn2、膜铁转运相关基因Tfr2,Slc40a1(Fpn1)、Steap3、线粒体亚铁血红素生成通路中酶的调控基因Cpox的mRNA表达均升高,Atg^(7-/-)小鼠骨量下降(P<0.05)。结论铁蓄积导致骨量下降可能与骨髓造血细胞自噬功能抑制相关;骨髓造血细胞自噬异常与骨量下降存在相关性。Objective Iron accumulation is related to the occurrence of postmenopausal osteoporosis.Meanwhile,autophagy abnormality of bone marrow hematopoietic cells is observed in hip osteoporotic fracture.This study is performed to investigate correlation between iron accumulation induced bone loss and hematopoietic autophagy dysfunction to explore the new risk factor of osteoporosis.Methods Male iron accumulation mice model was established by intraperitoneally injecting ferric ammonium citrate.Serum ferritin and osteogenic indicator P1NP were tested by ELISA.Bone mineral density was measured by micro-CT.Femur and tibia bone marrows were collected for hematopoietic stem and progenitor cells proportion and cell apoptosis analysis.Autolysosome formation was measured by image flow cytometry.We used conditional mouse model Atg7^(flox/flox);Vav-Cre(Atg^(7-/-))in which Atg7 had been genetically deleted in the hematopoietic system.Bone marrow hematopoietic stem and progenitor cells were collected for RNA sequence.micro-CT scan was conducted for Atg^(7-/-)femur.Results Ferritin level of iron accumulation mice was significantly higher than control group(P<0.05).Iron accumulation inhibited P1NP and induced decreased bone mineral density(P<0.05).Iron accumulation bone marrow displayed enhanced hematopoietic stem and progenitor cells proportion(P<0.05),with more cell apoptosis(P<0.05).Hematopoietic autophagy was deteriorated in iron accumulation bone marrow.Transcriptomic profiling showed up-regulation of iron activity in Atg^(7-/-)mice,with increased iron homeostasis and iron membrane transporter genes,including Lcn2,Tfr2,Slc40a1(Fpn1),Steap3,and Cpox.micro-CT revealed severe bone loss and decreased bone mineral density in Atg^(7-/-)mice(P<0.05).Conclusion Iron accumulation induced bone loss is related to inhibition of hematopoietic cells.Hematopoietic autophagy dysfunction is associated with bone loss.

关 键 词：铁蓄积 骨量下降 造血细胞 自噬 

分 类 号：R580[医药卫生—内分泌]