PDF(Pubmed)
Abstract：
UNASSIGNED: Microglial cell iron load and inflammatory activation are significant hallmarks of late-stage Alzheimer\'s disease (AD). In vitro, microglia preferentially upregulate the iron importer, divalent metal transporter 1 (DMT1, gene name Slc11a2) in response to inflammatory stimuli, and excess iron can augment cellular inflammation, suggesting a feed-forward loop between iron import mechanisms and inflammatory signaling. However, it is not understood whether microglial iron import mechanisms directly contribute to inflammatory signaling and chronic disease in vivo. These studies determined the effects of microglial-specific knockdown of Slc11a2 on AD-related cognitive decline and microglial transcriptional phenotype.
UNASSIGNED: In vitro experiments and RT-qPCR were used to assess a role for DMT1 in amyloid-β-associated inflammation. To determine the effects of microglial Slc11a2 knockdown on AD-related phenotypes in vivo, triple-transgenic Cx3cr1 Cre - ERT2 ;Slc11a2 flfl;APP/PS1 + or - mice were generated and administered corn oil or tamoxifen to induce knockdown at 5-6 months of age. Both sexes underwent behavioral analyses to assess cognition and memory (12-15 months of age). Hippocampal CD11b + microglia were magnetically isolated from female mice (15-17 months) and bulk RNA-sequencing analysis was conducted.
UNASSIGNED: DMT1 inhibition in vitro robustly decreased Aβ-induced inflammatory gene expression and cellular iron levels in conditions of excess iron. In vivo, Slc11a2 KD APP/PS1 female, but not male, mice displayed a significant worsening of memory function in Morris water maze and a fear conditioning assay, along with significant hyperactivity compared to control WT and APP/PS1 mice. Hippocampal microglia from Slc11a2 KD APP/PS1 females displayed significant increases in Enpp2, Ttr, and the iron-export gene, Slc40a1, compared to control APP/PS1 cells. Slc11a2 KD cells from APP/PS1 females also exhibited decreased expression of markers associated with disease-associated microglia (DAMs), such as Apoe, Ctsb, Csf1, and Hif1α.
UNASSIGNED: This work suggests a sex-specific role for microglial iron import gene Slc11a2 in propagating behavioral and cognitive phenotypes in the APP/PS1 model of AD. These data also highlight an association between loss of a DAM-like phenotype in microglia and cognitive deficits in Slc11a2 KD APP/PS1 female mice. Overall, this work illuminates an iron-related pathway in microglia that may serve a protective role during disease and offers insight into mechanisms behind disease-related sex differences.
UNASSIGNED: In vitro experiments and RT-qPCR were used to assess a role for DMT1 in amyloid-β-associated inflammation. To determine the effects of microglial Slc11a2 knockdown on AD-related phenotypes in vivo, triple-transgenic Cx3cr1 Cre - ERT2 ;Slc11a2 flfl;APP/PS1 + or - mice were generated and administered corn oil or tamoxifen to induce knockdown at 5-6 months of age. Both sexes underwent behavioral analyses to assess cognition and memory (12-15 months of age). Hippocampal CD11b + microglia were magnetically isolated from female mice (15-17 months) and bulk RNA-sequencing analysis was conducted.
UNASSIGNED: DMT1 inhibition in vitro robustly decreased Aβ-induced inflammatory gene expression and cellular iron levels in conditions of excess iron. In vivo, Slc11a2 KD APP/PS1 female, but not male, mice displayed a significant worsening of memory function in Morris water maze and a fear conditioning assay, along with significant hyperactivity compared to control WT and APP/PS1 mice. Hippocampal microglia from Slc11a2 KD APP/PS1 females displayed significant increases in Enpp2, Ttr, and the iron-export gene, Slc40a1, compared to control APP/PS1 cells. Slc11a2 KD cells from APP/PS1 females also exhibited decreased expression of markers associated with disease-associated microglia (DAMs), such as Apoe, Ctsb, Csf1, and Hif1α.
UNASSIGNED: This work suggests a sex-specific role for microglial iron import gene Slc11a2 in propagating behavioral and cognitive phenotypes in the APP/PS1 model of AD. These data also highlight an association between loss of a DAM-like phenotype in microglia and cognitive deficits in Slc11a2 KD APP/PS1 female mice. Overall, this work illuminates an iron-related pathway in microglia that may serve a protective role during disease and offers insight into mechanisms behind disease-related sex differences.
摘要：
背景小胶质细胞铁负荷和炎症激活是晚期阿尔茨海默病(AD)的重要标志。体外，小胶质细胞优先上调铁进口商，二价金属转运蛋白1（DMT1，基因名称Slc11a2）响应炎症刺激，过量的铁可以增加细胞炎症，提示铁输入机制和炎症信号之间存在前馈回路。然而,目前尚不清楚小胶质细胞铁输入机制是否直接导致体内炎症信号传导和慢性疾病.这些研究确定了Slc11a2的小胶质细胞特异性敲低对AD相关认知下降和小胶质细胞转录表型的影响。方法体外实验和RT-qPCR用于评估DMT1在淀粉样β相关炎症中的作用。为了确定体内小胶质细胞Slc11a2敲低对AD相关表型的影响，三转基因Cx3cr1Cre-ERT2;Slc11a2flfl;产生APP/PS1+或-小鼠,并给予玉米油或他莫昔芬以在5-6月龄时诱导敲低。两种性别都接受了行为分析以评估认知和记忆（12-15个月大）。从雌性小鼠（15-17个月）中磁性分离海马CD11b小胶质细胞，并进行大量RNA测序分析。结果在铁过量的条件下，体外DMT1抑制强烈降低了Aβ诱导的炎症基因表达和细胞铁水平。在体内,Slc11a2KDAPP/PS1女性，但不是男性,小鼠在Morris水迷宫中表现出明显的记忆功能恶化和恐惧条件测定，与对照WT和APP/PS1小鼠相比,伴随着显著的过度活跃。来自Slc11a2KDAPP/PS1雌性的海马小胶质细胞显示Enpp2，Ttr显着增加，和铁输出基因，Slc40a1,与对照APP/PS1细胞相比。来自APP/PS1雌性的Slc11a2KD细胞也表现出与疾病相关的小胶质细胞（DAMs）相关的标志物表达降低，比如Apoe,CTSB,Csf1,和Hif1α。结论这项工作表明，在AD的APP/PS1模型中，小胶质铁导入基因Slc11a2在传播行为和认知表型方面具有性别特异性作用。这些数据还强调了小胶质细胞中DAM样表型的丧失与Slc11a2KDAPP/PS1雌性小鼠中的认知缺陷之间的关联。总的来说,这项工作阐明了小胶质细胞中与铁相关的通路,该通路可能在疾病期间发挥保护作用,并提供了对疾病相关性别差异背后机制的洞察.
