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Assessing the mechanisms directing cell fate in the dorsal spinal cord

评估背侧脊髓细胞命运的机制

基本信息

批准号：
10615870
负责人：
SAMANTHA J BUTLER
金额：
$ 45.09万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-05-01 至 2027-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10615870
关键词：
Address Adopted Aftercare BMP4 Bone Morphogenetic Proteins Cell model Cells ChIP-seq Chicken Model Chickens Complex Data Development Developmental Biology Disease Dorsal Drug Modulation Drug Screening ES Cell Line Environment Family Family member Gene Expression Profiling Genetic Transcription Germ Cells Growth Factor In Vitro Individual Injury Interneurons Ligands Light Logic Mediating Medical Modality Modeling Mus Nature Nociception Outcome Pain Paralysed Pathway interactions Patients Pattern Peripheral Pluripotent Stem Cells Population Process Production Proliferating Proprioception Protein Family Protocols documentation Pruritus Reaction Research Resolution Role SHH gene Second Messenger Systems Sensory Series Signal Pathway Signal Transduction Signaling Protein Specific qualifier value Spinal Spinal Cord Spinal cord damage Subgroup System Touch sensation Translating Tretinoin Vertebral column WNT Signaling Pathway Well in self bone morphogenetic protein receptor type I cell type design differentiation protocol drug testing embryonic stem cell in vivo knock-down member morphogens motor control mouse model nerve stem cell neural progenitor receptor repaired response small molecule inhibitor somatosensory stem cell differentiation stem cell model transcription factor transcriptome transcriptomics

项目摘要

Project Summary The somatosensory system permits us to perceive and react to the environment through modalities that include touch, nociception, thermosensation and proprioception. Somatosensory information is received peripherally and then relayed centrally by different populations of dorsal interneurons (dIs; dI1-dI6) in the spinal cord. Our research objectives are to understand the mechanisms that establish dIs during development and then apply these principles towards designing differentiation protocols to direct the formation of specific populations of dIs from pluripotent stem cells. These cells have the potential to repair damaged sensory circuits and act as substrates for drug screening platforms. We have focused on dissecting the role of the bone morphogenetic protein (BMP) family in dI fate specification. BMPs were widely assumed to act as morphogens, patterning the dorsal spinal cord in a concentration-dependent mechanism similar to the manner in which sonic hedgehog (Shh) patterns the ventral spinal cord. However, our recent studies using mouse, chicken, and mouse embryonic stem cell (mESC) models have found that no evidence that BMPs act as morphogens. Rather, BMPs have signal-specific activities, with differential abilities to direct dorsal progenitor (dP) patterning and/or differentiation through specific type I BMP receptors. Our recent in vivo and in vitro studies have also suggested that dI fates are established in a series of nested choice points. In our model, spinal progenitors are dorsalized by retinoic acid (RA), subdivided into multipotential dP subgroups by BMP signaling, and then resolve into specific dI fates. Since little is known about this patterning process, we will assess in Aim 1 how multipotential dP fates are first established by RA and BMP signaling and identify the mechanisms directing multipotential dPs into specific dI identities. In Aim 2, we will determine the nature of the intracellular response that permits specific BMPs to drive dPs towards different dI identities, addressing two unresolved questions: [1] are canonical receptor regulated (R)-Smads activated in a BMP-specific manner to result in distinct patterning activities? And [2] what factors do the R-Smads in turn regulate to promote dI fates? Together, these studies will investigate a long-standing problem in developmental biology, i.e., understanding how specific outcomes arise from a common signal, and shed light on the specification of dIs, cell types needed to permit paralyzed patients to again interpret their sensory environment. Our specific aims are as follows: Aim 1: Identify the mechanism(s) that establish multipotential dPs and assign them into individual dI fates. Hypothesis: RA±BMP4 direct the formation of multipotential dP subgroups, which resolve into specific dI fates by the asymmetric activation of additional endogenous signaling pathways, such as the Wnt pathway. Aim 2: Assess the role of the Smad and Id families in BMP-induced dI fate specification. Hypothesis: BMPs differentially activate Smad1 and/or Smad5, to regulate the activity of Id family members.

项目摘要躯体感觉系统使我们能够感知环境，并对环境做出反应，包括触觉、伤害感受、温度感受和本体感受。体感信息被接收然后由脊髓中不同的背侧中间神经元（dIs; dI 1-dI 6）群体集中中继线.我们的研究目标是了解在发育过程中建立dIs的机制，然后将这些原则应用于设计分化方案，来自多能干细胞的dI群体。这些细胞具有修复受损感觉神经的潜力。电路和作为药物筛选平台的基板。我们着重分析了骨骼的作用形态发生蛋白（BMP）家族在dI命运规范中的作用。BMP被广泛认为是形态发生素，以浓度依赖性机制对脊髓背侧形成图案，类似于声波刺猬（Shh）图案腹侧脊髓。然而，我们最近的研究使用小鼠，鸡，小鼠胚胎干细胞（mESC）模型已经发现没有证据表明BMP作为形态发生剂。相反，BMP具有信号特异性活性，具有指导背侧祖细胞（dP）模式形成的不同能力和/或通过特异性I型BMP受体分化。我们最近的体内和体外研究也建议dI命运建立在一系列嵌套的选择点。在我们的模型中，由视黄酸（RA）背侧化，通过BMP信号转导细分为多能dP亚组，然后分解成特定的dI命运。由于我们对这种模式化过程知之甚少，我们将在目标1中评估如何多能dP命运首先通过RA和BMP信号传导建立，并确定了指导多能dPs转化为特定的dI身份。在目标2中，我们将确定细胞内反应的性质允许特定的BMP驱动dPs朝向不同的dI身份，解决了两个未解决的问题：[1] 是典型的受体调节的（R）-Smads，以BMP特异性方式激活，导致不同的模式活动？[2] R-Smads反过来又调节哪些因素来促进dI命运？这些研究一起将研究发育生物学中一个长期存在的问题，即，了解具体的结果从一个共同的信号，并阐明了规格的dIs，细胞类型需要允许瘫痪患者再次解释他们的感觉环境。我们的具体目标如下：目的1：确定建立多能dPs的机制，并将其分配到单个dI命运中。假设：RA± BMP 4指导多能dP亚群的形成，这些亚群分解为特定的dI命运通过不对称激活额外的内源性信号传导途径，如Wnt途径。目的2：评估Smad和Id家族在BMP诱导的dI命运特化中的作用。假设：BMP差异激活Smad 1和/或Smad 5，以调节Id家族成员的活性。