Tan James-Kevin Y, Pham Binhan, Zong Yujin, Perez Camilo, Maris Don O, Hemphill Ashton, Miao Carol H, Matula Thomas J, Mourad Pierre D, Wei Hua, Sellers Drew L, Horner Philip J, Pun Suzie H
Department of Bioengineering, University of Washington, Seattle, WA 98195, USA; Molecular Engineering and Sciences Institute, University of Washington, Seattle, WA 98195, USA.
Center for Industrial and Medical Ultrasound, University of Washington, Seattle, WA 98195, USA; Department of Biomedical Engineering, Xian Jiaotong University, Xi'an, 710049, China.
J Control Release. 2016 Jun 10;231:86-93. doi: 10.1016/j.jconrel.2016.02.003. Epub 2016 Feb 6.
Neurons in the brain can be damaged or lost from neurodegenerative disease, stroke, or traumatic injury. Although neurogenesis occurs in mammalian adult brains, the levels of natural neurogenesis are insufficient to restore function in these cases. Gene therapy has been pursued as a promising strategy to induce differentiation of neural progenitor cells into functional neurons. Non-viral vectors are a preferred method of gene transfer due to potential safety and manufacturing benefits but suffer from lower delivery efficiencies compared to viral vectors. Since the neural stem and progenitor cells reside in the subventricular zone of the brain, intraventricular injection has been used as an administration route for gene transfer to these cells. However, the choroid plexus epithelium remains an obstacle to delivery. Recently, transient disruption of the blood-brain barrier by microbubble-enhanced ultrasound has been used to successfully improve drug delivery to the brain after intravenous injection. In this work, we demonstrate that microbubble-enhanced ultrasound can similarly improve gene transfer to the subventricular zone after intraventricular injection. Microbubbles of different surface charges (neutral, slightly cationic, and cationic) were prepared, characterized by acoustic flow cytometry, and evaluated for their ability to increase the permeability of immortalized choroid plexus epithelium monolayers in vitro. Based on these results, slightly cationic microbubbles were evaluated for microbubble and ultrasound-mediated enhancement of non-viral gene transfer in vivo. When coupled with our previously reported gene delivery vehicles, the slightly cationic microbubbles significantly increased ultrasound-mediated transfection of the murine brain when compared to commercially available Definity® microbubbles. Temporary disruption of the choroid plexus by microbubble-enhanced ultrasound is therefore a viable way of enhancing gene delivery to the brain and merits further research.
大脑中的神经元可能因神经退行性疾病、中风或创伤性损伤而受损或丢失。尽管成年哺乳动物大脑中会发生神经发生，但在这些情况下，自然神经发生的水平不足以恢复功能。基因治疗一直被视为一种有前景的策略，可诱导神经祖细胞分化为功能性神经元。由于潜在的安全性和生产优势，非病毒载体是基因传递的首选方法，但与病毒载体相比，其递送效率较低。由于神经干细胞和祖细胞位于脑室下区，脑室内注射已被用作将基因传递给这些细胞的给药途径。然而，脉络丛上皮仍然是递送的障碍。最近，微泡增强超声对血脑屏障的短暂破坏已被用于成功改善静脉注射后药物向大脑的递送。在这项工作中，我们证明微泡增强超声同样可以改善脑室内注射后基因向脑室下区的传递。制备了不同表面电荷（中性、轻度阳离子和阳离子）的微泡，通过声流式细胞术进行表征，并评估它们在体外增加永生化脉络丛上皮单层通透性的能力。基于这些结果，对轻度阳离子微泡在体内微泡和超声介导的非病毒基因传递增强方面进行了评估。与我们之前报道的基因递送载体相结合时，与市售的Definity®微泡相比，轻度阳离子微泡显著增加了超声介导的小鼠脑转染。因此，微泡增强超声对脉络丛的暂时破坏是增强基因向大脑递送的一种可行方法，值得进一步研究。
