Ionis Pharmaceuticals, Inc. 2855 Gazelle Court, Carlsbad, CA 92010, USA.
Nucleic Acids Res. 2020 May 7;48(8):4382-4395. doi: 10.1093/nar/gkaa164.
Conjugation of antisense oligonucleotide (ASO) with a variety of distinct lipophilic moieties like fatty acids and cholesterol increases ASO accumulation and activity in multiple tissues. While lipid conjugation increases tissue exposure in mice and reduces excretion of ASO in urine, histological review of skeletal and cardiac muscle indicates that the increased tissue accumulation of lipid conjugated ASO is isolated to the interstitium. Administration of palmitic acid-conjugated ASO (Palm-ASO) in mice results in a rapid and substantial accumulation in the interstitium of muscle tissue followed by relatively rapid clearance and only slight increases in intracellular accumulation in myocytes. We propose a model whereby increased affinity for lipid particles, albumin, and other plasma proteins by lipid-conjugation facilitates ASO transport across endothelial barriers into tissue interstitium. However, this increased affinity for lipid particles and plasma proteins also facilitates the transport of ASO from the interstitium to the lymph and back into circulation. The cumulative effect is only a slight (∼2-fold) increase in tissue accumulation and similar increase in ASO activity. To support this proposal, we demonstrate that the activity of lipid conjugated ASO was reduced in two mouse models with defects in endothelial transport of macromolecules: caveolin-1 knockout (Cav1-/-) and FcRn knockout (FcRn-/-).
将反义寡核苷酸（ASO）与各种不同的亲脂性部分（如脂肪酸和胆固醇）缀合，可以增加 ASO 在多种组织中的积累和活性。虽然脂质缀合增加了小鼠组织中的暴露量，并减少了 ASO 在尿液中的排泄，但对骨骼肌和心肌的组织学检查表明，脂质缀合的 ASO 增加的组织积累仅限于间质。在小鼠中给予棕榈酸缀合的 ASO（Palm-ASO）会导致间质中 ASO 的快速和大量积累，随后清除速度相对较快，仅在肌细胞中略微增加细胞内积累。我们提出了一种模型，即脂质缀合增加了对脂质颗粒、白蛋白和其他血浆蛋白的亲和力，从而促进 ASO 穿过内皮屏障进入组织间质。然而，这种对脂质颗粒和血浆蛋白的亲和力增加也促进了 ASO 从间质向淋巴和再循环的运输。累积效应仅导致组织积累略有增加（约 2 倍）和 ASO 活性相似增加。为了支持这一假设，我们证明了在两种内皮大分子转运缺陷的小鼠模型中，脂质缀合的 ASO 的活性降低：窖蛋白-1 敲除（Cav1-/-）和 FcRn 敲除（FcRn-/-）。
