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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.

项目概要体感系统使我们能够通过以下方式感知环境并对环境做出反应：包括触觉、痛觉、热觉和本体觉。接收体感信息外周，然后由脊髓中不同群体的背侧中间神经元（dIs；dI1-dI6）集中转发绳索。我们的研究目标是了解在开发和生产过程中建立 dIs 的机制然后应用这些原则来设计分化方案以指导特定的形成来自多能干细胞的 dIs 群体。这些细胞有潜力修复受损的感觉电路并充当药物筛选平台的底物。我们重点剖析骨骼的作用 dI 命运规范中的形态发生蛋白 (BMP) 家族。人们普遍认为 BMP 具有形态发生素的作用，以浓度依赖性机制形成背侧脊髓图案，类似于声波的方式刺猬 (Shh) 塑造腹侧脊髓。然而，我们最近使用小鼠、鸡和小鼠胚胎干细胞 (mESC) 模型发现没有证据表明 BMP 具有形态发生素的作用。相反，BMP 具有信号特异性活性，具有指导背侧祖细胞 (dP) 模式的不同能力和/或通过特定的 I 型 BMP 受体进行分化。我们最近的体内和体外研究也表明 dI 命运是建立在一系列嵌套选择点中的。在我们的模型中，脊柱祖细胞是通过视黄酸 (RA) 进行背侧化，通过 BMP 信号将其细分为多能 dP 亚组，然后解析为特定的 dI 命运。由于对这个模式化过程知之甚少，我们将在目标 1 中评估如何多潜能 dP 命运首先由 RA 和 BMP 信号传导建立，并确定指导机制将多潜能 dP 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 推动 dP 走向不同的 DI 身份，解决两个未解决的问题：[1] 是典型受体调节 (R)-Smads，以 BMP 特异性方式激活，从而产生不同的图案活动？ [2] R-Smads 又会调节哪些因素来促进 dI 命运？这些研究共同将研究发育生物学中长期存在的问题，即了解具体结果如何由共同信号产生，并揭示了 dIs 的规范，即允许瘫痪所需的细胞类型患者再次解释他们的感官环境。我们的具体目标如下：目标 1：确定建立多潜能 dP 并将其分配给各个 dI 命运的机制。假设：RA±BMP4 直接形成多能 dP 亚群，并分解为特定的 dI 命运通过其他内源信号通路（例如 Wnt 通路）的不对称激活。目标 2：评估 Smad 和 Id 家族在 BMP 诱导的 dI 命运规范中的作用。假设：BMP 差异性激活 Smad1 和/或 Smad5，以调节 Id 家族成员的活性。