Compositions and methods for enhanced fluorine-19 magnetic resonance imaging cell tracking

对于细胞疗法的临床开发者，如免疫细胞和干细胞，一个共同的需求是非- 侵入性意味着观察注射后细胞的命运。细胞运输的成像可以提供关键的 关于持久性、运动性、最佳递送途径和治疗剂量的反馈。该项目旨在 合成和生物学评估创新的新型成像探针，用于敏感的体内细胞跟踪， 氟-19（19 F）磁共振成像（MRI）。我们将推进一种引人注目的配方科学， 新型“金属-全氟化碳”（MPFC）纳米乳液成像探针。这些探员将是关键 元件，以多管齐下的策略，将细胞检测灵敏度提高一个数量级， 19 F MRI细胞检测技术。总体而言，在19 F细胞追踪中，感兴趣的细胞群最初标记在19 F细胞中。 使用全氟化碳纳米乳液培养。在转移至受试者后，使用细胞培养仪在体内追踪细胞。 19F MRI。细胞内的氟产生细胞特异性图像，没有背景信号。之一 阻止更广泛地采用基于19 F的小区跟踪的瓶颈是对稀疏小区数量的敏感性限制。 该技术的灵敏度可以通过三管齐下的方法来提高：（1）分子设计和 合成以提高分子信号发生器的固有灵敏度和（2）纳米乳液探针 具有细胞靶向以增强细胞内递送和摄取的制剂，以及（3）采用MRI数据 具有更有效的每采集时间信噪比（SNR/t）的采集方案。最近的结果 已经证明了通过分子设计极大地增强了氟MRI的灵敏度。我们创建了一个 一类新型分子，将高度氟化的纳米乳液与金属的磁性结合起来，联合收割机 溶解到氟相中。溶解的顺磁性金属离子提供了显著的降低， 19 F自旋-晶格弛豫时间，从而提高SNR/t和细胞检测灵敏度。人们发现 铁是增强氟MRI信号最有效的金属。根据这些初步结果， 该提案有四个具体目标：目标1。MPFC的螯合策略。我们将评估一系列合适的 螯合分子和合成策略，以稳定地将金属离子引入PFC。增强型小区 使用细胞穿透肽（CPP）递送MPFC纳米乳液。成功的MRI检测细胞 关键地需要离体乳化MPFC的最佳细胞内递送。我们将开发新型MPFC 结合了连接到纳米乳液表面活性剂的CPP的纳米乳液制剂， 标记细胞用于细胞跟踪。目标3：“智能”体内靶向纳米乳剂。作为一个探索性的延伸， 工作，我们设计了MPFC纳米乳液，靶向体内肿瘤。目标4。跟踪的体内成像方法 免疫调节T细胞在癌症中的作用为了评估新的MPFC纳米乳液探针，我们将标记T细胞， 将其传递给免疫癌症模型。为了对这些模型进行成像，稀疏采样MRI采集 方法（例如，压缩感测）将被实现并针对MPFC代理进行优化以最大化SNR/t。

A common need for clinical developers of cell therapies, such as immunotherapeutic and stem cells, is a non- invasive means to visualize the fate of cells following injection. Imaging of cell trafficking can provide critical feedback regarding the persistence, motility, optimal routes of delivery and therapeutic doses. This project aims to synthesize and biologically evaluate innovative new imaging probes for sensitive in vivo cell tracking using fluorine-19 (19F) magnetic resonance imaging (MRI). We will advance the formulation science of a compelling new class of ‘metallo-perfluorocarbon’ (MPFC) nanoemulsion imaging probes. These agents will be a key element to a multi-pronged strategy to advance cell detection sensitivity by an order of magnitude over current 19F MRI cell detection technologies. Overall, in 19F cell tracking, cell populations of interest are initially labeled in culture using perfluorocarbon nanoemulsions. Following transfer to the subject, cells are tracked in vivo using 19F MRI. The fluorine inside the cells yields cell-specific images, with no background signal. One of the bottlenecks preventing the broader adoption of 19F based cell tracking is sensitivity limits to sparse cell numbers. The sensitivity of this technology can be improved by a three-pronged approach: (1) molecular design and synthesis to improve the intrinsic sensitivity of the molecular signal generator and (2) nanoemulsion probe formulation with cell targeting to enhance intracellular delivery and uptake, and (3) employing MRI data acquisition schemes that have a more efficient signal-to-noise ratio per acquisition time (SNR/t). Recent results have demonstrated dramatically-enhanced sensitivity of fluorine MRI by molecular design. We have created a new class of molecules that combine highly fluorinated nanoemulsions with the magnetic properties of metals that are solubilized into the fluorous phase. Solubilized paramagnetic metal ions provide a dramatic reduction in the 19F spin-lattice relaxation time thereby enhancing SNR/t and cell detection sensitivity. It was discovered that iron is most effective metal at enhancing the fluorine MRI signal. Building on these preliminary results, the proposal has four Specific Aims: Aim 1. Chelation strategies for MPFCs. We will evaluate a range of suitable chelate molecules and synthesis strategies to stably incorporate metal ions into PFC. Aim 2. Enhanced cell delivery of MPFC nanoemulsion using cell penetrating peptides (CPPs). Successful MRI detection of cells critically requires optimal intracellular delivery of emulsified MPFC ex vivo. We will develop novel MPFC nanoemulsion formulations incorporating CPPs attached to the nanoemulsion surfactant to rapidly and optimally label cells for cell tracking. Aim 3. “Smart” in vivo targeted nanoemulsions. As an exploratory extension of this work, we devise MPFC nanoemulsions that target tumors in vivo. Aim 4. In vivo imaging methods to track immunotherapeutic T cells in cancer. To evaluate new MPFC nanoemulsion probes, we will label T cells and deliver these to immunotherapeutic cancer models. To image these models, sparse sampling MRI acquisition methods (e.g., compressed sensing) will be implemented and optimized for MPFC agents to maximize SNR/t.