Calcium sensors for molecular fMRI

用于分子功能磁共振成像的钙传感器

• 批准号: 8934224
• 负责人: Alan Jasanoff
• 金额: $ 38.21万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-30 至 2017-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8934224
• 关键词: Achievement; Acids; Animals; Area; BRAIN initiative; Blood - brain barrier anatomy; Brain; Buffers; Calcium; Calcium Binding; Cell Culture Techniques; Cells; Characteristics; Chelating Agents; Chemicals; Complex; Contrast Media; Development; Diagnosis; Esterification; Esters; Ethane; Family; Family suidae; Functional Imaging; Functional Magnetic Resonance Imaging; Funding; Human; Image; Imaging Techniques; In Vitro; Individual; Injection of therapeutic agent; Ionomycin; Iron; Label; Life; Liver; Magnetic Resonance Imaging; Manganese; Maps; Measures; Mediating; Membrane; Metals; Methodology; Methods; Modeling; Molecular; Neuroglia; Neurons; Neurosciences; Neurotransmitters; Optics; Pattern; Permeability; Population; Rattus; Research; Resolution; Rodent; Specificity; Techniques; Testing; Ultrasonography; Validation; Weight; Work; base; blood oxygen level dependent; carboxylate; cell type; chemical group; chemical property; design; esterase; in vivo; innovation; minimally invasive; nervous system disorder; neural circuit; neuroimaging; neurotransmission; neurotransmitter release; next generation; non-invasive imaging; novel; novel strategies; public health relevance; relating to nervous system; research study; sensor; signal processing; somatosensory

 DESCRIPTION (provided by applicant): The development of minimally invasive direct readouts of neural activity is one of the greatest challenges facing neuroscience today. Our recent work has shown that it is possible to perform high resolution functional magnetic resonance imaging (fMRI) of molecular-level phenomena using MRI contrast agents sensitive to hallmarks of neurotransmitter release. An even more valuable contribution would be the creation of calcium sensors suitable for molecular fMRI of intracellular neural signaling processes. Functional imaging performed with these sensors would combine the noninvasiveness and whole-brain coverage of MRI with the molecular specificity and broad applicability of established optical calcium neuroimaging techniques. Calcium-dependent fMRI will be a breakthrough technique for analysis of neural circuits in animals, with potential longer term applications in humans. The technique could achieve cellular resolution in conjunction with ultrahigh field MRI scanners and cell labeling techniques. A major hurdle in realizing this advance is the creation of effective calcium-dependent MRI contrast agents, however. This proposal describes strategies for creating novel MRI calcium probes suitable for molecular fMRI, as well as initial experiments that validate the approach in animals. Innovations include the rational design of membrane permeable probes themselves as well as approaches for in vivo calcium imaging and genetically targeted applications. In Aim 1, we synthesize MRI calcium sensors based on paramagnetic cell-permeable aromatic chelates and characterize them in vitro. In Aim 2, we form acetomethoxy derivatives of the calcium probes and validate them first in cell culture and then in rats, using a somatosensory stimulation paradigm. Results of Aim 2 will direct further refinement of the probes, if necessary. In Aim 3, we adapt the calcium sensors for intracellular trapping by selective esterases that will promote probe accumulation in genetically targeted cells. This technique will provide a means for cell type-specific and in some cases individual cell-specific functional imaging of dynamic calcium levels in the brain. Potential impact of the project and preliminary achievements of the research team make this next-generation neuroimaging project particularly suitable for BRAIN Initiative funding under RFA-NS-14-007.

 描述（由申请人提供）：神经活动的微创直接读数的发展是当今神经科学面临的最大挑战之一，我们最近的工作表明，可以对分子进行高分辨率功能磁共振成像（fMRI）。使用对神经递质释放特征敏感的 MRI 造影剂来观察水平现象，更有价值的贡献是创建适用于细胞内神经信号传导过程的分子 fMRI 的钙传感器，将无创性和功能性成像结合起来。 MRI 的全脑覆盖以及已建立的光学钙神经成像技术的分子特异性和广泛适用性将成为分析动物神经回路的突破性技术，该技术可能会在人类中实现长期应用。分辨率与超高场 MRI 扫描仪和细胞标记技术相结合，实现这一进步的一个主要障碍是创建有效的钙依赖性 MRI 造影剂，然而，该提案描述了创建适用于分子 fMRI 的新型 MRI 钙探针的策略。以及在动物身上验证该方法的初步实验。创新包括膜渗透性探针本身的合理设计以及体内钙成像和基因靶向应用的方法。在目标 1 中，我们合成了基于顺磁性细胞渗透性的 MRI 钙传感器。在目标 2 中，我们形成了钙探针的乙酰甲氧基衍生物，并首先在细胞培养物中进行验证，然后在大鼠中使用体感刺激范例进行验证。如有必要，目标 2 将指导探针的进一步细化。在目标 3 中，我们通过选择性酯酶调整钙传感器，以促进探针在遗传靶向细胞中的积累。在某些情况下，该项目的潜在影响和研究团队的初步成果使该下一代神经影像项目特别适合 BRAIN Initiative 资助。 RFA-NS-14-007。