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、伤害感受、热感觉和本体感觉信息。外周，然后由脊柱中不同群体的背侧中间神经元（dIs；dI1-dI6）集中转发我们的研究目标是了解在开发和部署过程中建立 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 群体具有修复受损感觉的潜力。我们专注于剖析骨骼的作用。 dI 命运规范中的形态发生蛋白 (BMP) 家族被广泛认为充当形态发生素，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）模式是腹侧脊髓，但我们最近的研究使用了小鼠、鸡和小鼠。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。表明 dI 命运是在一系列嵌套选择点中建立的，在我们的模型中，脊柱祖细胞是建立在一系列嵌套选择点上的。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 中评估如何实现。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 [2] R-Smads 反过来调节哪些因素来促进 dI 命运？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读他们的感官环境，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。