Mitochondria mediated intercellular metabolic coupling in bone marrow regeneration

摘要 造血干细胞和祖细胞（HSPC）移植（HSCT）常规用于治疗骨髓增生异常综合征。 治疗先天性错误。离体基因编辑/治疗正在成为治疗癌症的成功工具。 骨髓（BM）衰竭（BMF）和免疫缺陷患者。然而，完整的 在这些患者中植入HSC需要大于预期的细胞剂量和HSC移植 可用于改善骨质疏松症等骨疾病。这些意想不到的观察 还没有进行严格的机理分析。 线粒体是众所周知的代谢传感器，其桥接转录特征和细胞信号。 功能协调发展的HSC的线粒体含量升高，但优先利用糖酵解和低 大量实验数据支持HSC中的线粒体活性表明， HSC的线粒体呼吸比它们的细胞后代的线粒体呼吸更慢。 我们的初步数据表明，线粒体转移存在于造血细胞和它们的 周围微环境对造血和间充质细胞的功能影响 骨髓消融后的再生。我们的数据表明，存在精细的配置， 线粒体命运定义HSC和再生骨髓中的微环境命运， 由两个主要分子节点控制的代谢偶联。我们假设HSPC线粒体 HSPC和BM的MSC/P之间的代谢偶联需要转移。这个目标 建议是定义控制线粒体内容和从线粒体转移的机制。 造血移植细胞及其对BM间充质再生的影响。我们将阐明 BM生态位中线粒体转移的机制及其功能相关性， 功能获得和丧失的药理学工具， HSC生态位中线粒体运输的生化后果。线粒体转移 重新编程受体BM MSC/P的代谢组，这种重新编程对于 间充质增殖和BM以及骨的间充质生态位的重建 骨髓消融后BM的再生。我们将确定a）负调节作用是否 线粒体转移中的Cx43依赖于细胞与细胞的接触; B）从BM的线粒体转移 HSPC到BM MSC/P诱导间充质微环境的代谢重编程 导致造血再生;和，c）防止AMPK活化是BM 间充质和造血再生。这一提议将在分子基础上提供光， 移植后造血依赖性间充质再生，并将确定的作用， 造血Cx43和宿主AMPK活性对骨髓代谢偶联的影响。

ABSTRACT Hematopoietic stem and progenitor cell (HSPC) transplantation (HSCT) is routinely used for the treatment of inborn errors. Ex vivo gene editing/therapy is becoming a successful tool for treatment of patients with bone marrow (BM) failure (BMF) and immunodeficiencies. However, the complete engraftment of HSC in these patients requires larger-than-expected cell doses and HSC transplantation is useful in ameliorating bone diseases like osteogenesis imperfecta. These unexpected observations have not been followed by a stringent mechanistic analysis. Mitochondria are well known metabolic sensors that bridge transcriptional signatures and cellular functions. The mitochondrial content of HSC is elevated but the preferential use of glycolysis and low mitochondrial activity in HSC as supported by a large cohort of experimental data suggest that mitochondrial respiration is more dispensable for HSC than for their cell progeny. Our preliminary data indicate that mitochondrial transfer exists between hematopoietic cells and their surrounding microenvironment with functional consequences on hematopoietic and mesenchymal regeneration after myeloablation. Our data suggests the existence of refined configuration of the mitochondrial fate defining the HSC and microenvironment fate in the regenerating bone marrow by metabolic coupling controlled by two major molecular nodes. We hypothesize that HSPC mitochondria transfer is required for metabolic coupling between HSPC and MSC/P of the BM. The goal of this proposal is to define the mechanisms that control the mitochondrial content and transfer from hematopoietic engrafting cells and their impact on BM mesenchymal regeneration. We will elucidate the mechanisms of mitochondrial transfer in the BM niche and their functional relevance using genetic and pharmacological tools of gain- and loss-of-function and enumeration and functional analysis of biochemical consequences of the traffic of mitochondria in the HSC niche. The mitochondrial transfer reprograms the metabolome of recipient BM MSC/P and this reprogramming is necessary for mesenchymal proliferation and reconstitution of the mesenchymal niche of the BM as well as bone regeneration of the BM after myeloablation. We will determine whether a) the negative regulator role of Cx43 in mitochondrial transfer depends on cell-to-cell contact; b) the mitochondrial transfer from BM HSPC to BM MSC/P induces metabolic reprogramming of the mesenchymal microenvironment resulting in hematopoietic regeneration; and, c) the prevention of AMPK activation is required for BM mesenchymal and hematopoietic regeneration. This proposal will provide light on the molecular basis of hematopoietic-dependent mesenchymal regeneration after transplantation and will identify the role of hematopoietic Cx43 and host AMPK activity on bone marrow metabolic coupling.