Regulation of hematopoiesis by sclerostin in specific niche cells in vivo

体内特定生态位细胞中硬化蛋白对造血的调节

• 批准号: 9489954
• 负责人: JENNIFER O MANILAY
• 金额: $ 10.14万
• 依托单位: UNIVERSITY OF CALIFORNIA, MERCED
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9489954
• 关键词: Activities of Daily Living; Adult; Adverse effects; Affect; Age; Aging; Animals; Antibodies; Behavior; Biological Assay; Biology; Blood; Bone Diseases; Bone Marrow; Bone Marrow Transplantation; Cell Cycle; Cell Differentiation process; Cell Maintenance; Cell division; Cell physiology; Cells; Characteristics; Clinical Treatment; Clinical Trials; Coculture Techniques; Communication; Data; Degenerative Disorder; Development; Endothelial Cells; Epigenetic Process; Experimental Models; Exposure to; Flow Cytometry; Future; Gene Expression Profiling; Genes; Genome; Goals; Hematopoiesis; Hematopoietic; Hematopoietic Stem Cell Transplantation; Hematopoietic System; Hematopoietic stem cells; Homeostasis; Human; Immune; Immune system; Immunity; In Vitro; Knock-out; Knockout Mice; Knowledge; Laboratories; Life; Maintenance; Measurement; Mediating; Mediator of activation protein; Mesenchymal Stem Cells; Minerals; Molecular; Osteoblasts; Osteoclasts; Osteocytes; Osteoporosis; Patients; Play; Population; Proteins; Regulation; Role; Skeletal bone; Skeletal system; Sorting - Cell Movement; Stem cells; Stromal Cells; Supporting Cell; System; Testing; Transplantation; WNT Signaling Pathway; bone; bone cell; bone mass; cell behavior; cell type; chemotherapy; differential expression; hematopoietic stem cell fate; in vivo; mouse model; novel; prevent; progenitor; public health relevance; self-renewal

 DESCRIPTION (provided by applicant): Crosstalk between cells of the bone microenvironment and hematopoietic cells affects each other's behavior, but a significant knowledge gap exists in the basic biology of the interactions and communication between osteolineage cells and hematopoietic stem cells (HSCs) in the adult. Filling this knowledge gap is important, as it has potential significance for understanding how healthy HSCs are maintained or altered in diseases of the bone and with ageing. The overall goal of this project is to identify the mechanisms that control HSC maintenance and differentiation in the bone marrow, and define which of these mechanisms are affected by cell-extrinsic changes in the bone. Sclerostin (abbreviated Sost for the gene, SOST for the protein) is a novel mediator of cellular communication between the skeletal and hematopoietic systems. SOST is a secreted protein that is produced primarily by osteocytes (OCYs), the mineralized bone cells embedded within the bone. SOST is a Wnt signaling antagonist that is critical for normal bone homeostasis. In Sost-knockout (SostKO) mice, the transition from osteoblasts to OCYs is uncontrolled, leading to massive increases in bone mass. Previous studies connected the misexpression of other secreted Wnt antagonists with dysregulated bone homeostasis and poor maintenance of long-term HSCs (LT-HSCs). However, the role of SOST on LT-HSC maintenance, cell cycling and differentiation still remains an open question. The adult bone marrow contains non-hematopoietic "niche" cells that support HSCs, such as mesenchymal stem cells (MSCs), osteoblasts (OBs) and endothelial cells (ECs). MSCs and OBs play dual roles as progenitors of OCYs and as niche cells for HSCs. SostKO mice display increased numbers of MSCs, OBs and ECs, but the effects the loss of Sost on their functional ability of maintain LT-HSCs are not known. The proposed studies will test the hypothesis that dysregulated bone homeostasis caused by Sost-depletion alters bone microenvironments in ways that directly affect the maintenance of LT-HSCs. The SostKO mouse model will be utilized as recipients in serial LT-HSC transplantation assays to discriminate between permanent or temporary changes of LT-HSC behavior after exposure to SostKO microenvironments. Cell-intrinsic characteristics of LT-HSCs that change due to the loss of Sost in the BM niche, such as altered LT-HSC cell division rates, levels of Wnt signaling activation, and evidence of epigenetic changes to the LT-HSC genome will be evaluated. In parallel, flow cytometric sorting will be used to dissect the distinct roles of SostKO MSCs, OBs, and ECs in the regulation of LT-HSC fate. Short-term in vitro co-culture assays will distinguish whether it is the interactions of LT-HSCs with MSCs, ECs, and/or OBs that influences LT-HSC fate, and gene expression analysis in sorted niche cell populations will identify differentially expressed genes that are involved in HSC maintenance. Taken together, the proposed studies will generate important new information on how Sost-deficiency affects LT-HSC maintenance and define the molecular and cellular players that are involved in HSC/niche crosstalk.

 描述（申请人提供）：骨微环境细胞和造血细胞之间的串扰影响彼此的行为，但成人骨系细胞和造血干细胞（HSC）之间相互作用和通讯的基础生物学方面存在显着的知识差距填补这一知识空白很重要，因为它对于了解健康的 HSC 在骨骼疾病和衰老过程中如何维持或改变具有潜在意义。该项目的总体目标是确定。 控制骨髓中 HSC 维持和分化的机制，并确定哪些机制受到骨骼中细胞外在变化的影响。 Sclerostin（基因缩写为 Sost，蛋白质缩写为 SOST）是一种新型的细胞通讯介质。 SOST 是一种分泌蛋白，主要由骨细胞 (OCY) 产生，嵌入骨骼内的矿化骨细胞中。在Sost敲除（SostKO）小鼠中，从成骨细胞到OCY的转变不受控制，导致骨量大量增加，之前的研究将其他分泌性Wnt拮抗剂的错误表达与骨稳态失调和不良联系起来。然而，SOST 在 LT-HSC 维持、细胞周期和分化中的作用仍然是一个悬而未决的问题。骨髓中含有支持 HSC 的非造血“生态位”细胞，例如间充质干细胞 (MSC)、成骨细胞 (OB) 和内皮细胞 (EC)，MSC 和 OB 发挥着 OCY 祖细胞和 HSC 生态位细胞的双重作用。 SostKO 小鼠表现出 MSC、OB 和 EC 数量增加，但失去 Sost 会影响其维持功能的能力LT-HSC 尚不清楚，拟议的研究将验证由 Sost 耗竭引起的骨稳态失调以直接影响 LT-HSC 维持的方式改变骨微环境的假设。SostKO 小鼠模型将用作连续 LT 的受体。 -HSC 移植测定可区分暴露于 SostKO 微环境后 LT-HSC 的细胞内在特征发生的永久性或暂时性变化。将评估 BM 生态位中 Sost 丢失的影响，例如 LT-HSC 细胞分裂率的改变、Wnt 信号激活水平以及 LT-HSC 基因组表观遗传变化的证据。同时，将使用流式细胞术分选。剖析不同的 SostKO MSC、OB 和 EC 在 LT-HSC 命运调节中的作用将区分 LT-HSC 与 MSC、EC 和/或 OB 的相互作用是否影响 LT。 -HSC 命运和分选的微环境细胞群中的基因表达分析将识别参与 HSC 维持的差异表达基因。总而言之，拟议的研究将产生关于如何维持的重要新信息。 Sost 缺乏会影响 LT-HSC 的维持，并定义参与 HSC/生态位串扰的分子和细胞参与者。

项目成果

Sclerostin Depletion Induces Inflammation in the Bone Marrow of Mice.

• DOI: 10.3390/ijms22179111
• 发表时间: 2021-08-24
• 期刊: International journal of molecular sciences
• 影响因子: 5.6
• 作者: Donham C;Chicana B;Robling AG;Mohamed A;Elizaldi S;Chi M;Freeman B;Millan A;Murugesh DK;Hum NR;Sebastian A;Loots GG;Manilay JO
• 通讯作者: Manilay JO