Ralvenius William T, Andresen Jason L, Huston Margaret M, Penney Jay, Bonner Julia Maeve, Fenton Owen S, Langer Robert, Tsai Li-Huei
Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Adv Mater. 2024 Feb;36(8):e2309225. doi: 10.1002/adma.202309225. Epub 2023 Dec 8.
Neuroinflammation is a hallmark of neurodegenerative disorders including Alzheimer's disease (AD). Microglia, the brain's immune cells, express many of the AD-risk loci identified in genome wide association studies and present a promising target for anti-inflammatory RNA therapeutics but are difficult to transfect with current methods. Here, several lipid nanoparticle (LNP) formulations are examined, and a lead candidate that supports efficient RNA delivery in cultures of human stem cell-derived microglia-like cells (iMGLs) and animal models of neuroinflammation is identified. The lead microglia LNP (MG-LNP) formulation shows minimal toxicity and improves delivery efficiency to inflammatory iMGLs, suggesting a preference for delivery into activated microglia. Intraperitoneal injection of the MG-LNP formulation generates widespread expression of the delivered reporter construct in all organs, whereas local intracisternal injection directly into the cerebrospinal fluid leads to preferential expression in the brain. It is shown that LNP-mediated delivery of siRNA targeting the PU.1 transcription factor, a known AD-risk locus, successfully reduces PU.1 levels in iMGLs and reduces neuroinflammation in mice injected with LPS and in CK-p25 mice that mimic the chronic neuroinflammation seen in AD patients. The LNP formulation represents an effective RNA delivery vehicle when applied intrathecally and can be broadly utilized to test potential neuroinflammation-directed gene therapies.
神经炎症是包括阿尔茨海默病（AD）在内的神经退行性疾病的一个标志。小胶质细胞作为大脑的免疫细胞，表达了全基因组关联研究中确定的许多AD风险位点，是抗炎RNA疗法的一个有前景的靶点，但目前的方法难以对其进行转染。在此，研究了几种脂质纳米颗粒（LNP）制剂，并确定了一种在人干细胞衍生的小胶质细胞样细胞（iMGLs）培养物和神经炎症动物模型中支持高效RNA递送的主要候选制剂。主要的小胶质细胞LNP（MG-LNP）制剂显示出最小的毒性，并提高了对炎性iMGLs的递送效率，表明其倾向于递送至活化的小胶质细胞。腹腔注射MG-LNP制剂可在所有器官中广泛表达所递送的报告基因构建体，而直接向脑脊液中进行局部脑池内注射则导致在脑中优先表达。结果表明，LNP介导的靶向已知AD风险位点PU.1转录因子的siRNA递送成功降低了iMGLs中PU.1的水平，并减轻了注射脂多糖的小鼠和模拟AD患者慢性神经炎症的CK-p25小鼠中的神经炎症。当鞘内应用时，LNP制剂是一种有效的RNA递送载体，可广泛用于测试潜在的针对神经炎症的基因疗法。
