Division of Molecular Pharmaceutics and Center for Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, USA.
Division of Molecular Pharmaceutics and Center for Nanotechnology in Drug Delivery, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, USA.
J Control Release. 2013 Nov 28;172(1):179-189. doi: 10.1016/j.jconrel.2013.08.015. Epub 2013 Aug 23.
A novel recombinant protein tetra-H2A (TH) derived from histone H2A has been developed to replace protamine as a conditionally reversible, nucleic acid condensing agent. The novel protein will address the insufficient release of nucleic acid therapeutics, which is captured by protamine for siRNA delivery. TH is composed of 4 tandem repeats of the histone H2A N-terminal sequence, intervened by the cathepsin D cleavage site. The repeating H2A sequence enhances the binding affinity to anionic nucleic acids, forming more stable condensates, as demonstrated by the binding affinity assay. The TH/siRNA condensates are formulated into a core-membrane structured liposomal nanoparticle (NP). The endosomes of cancer cells are rich in cathepsin D, allowing on-site degradation of TH and facilitating the intracellular release of siRNA. The NPs assembled with TH produced a higher silencing efficiency of target genes in vitro and in vivo than the NPs assembled with protamine as the nucleic acid condensing agent. The exploitation of TH in the NP formulation exhibited a biocompatibility profile similar to that of protamine, with minimal immunostimulating and systemic toxicity observed after repeated administration.
一种新型重组蛋白四聚体 H2A（TH）已被开发出来，以替代鱼精蛋白作为一种条件可逆的核酸缩合剂。这种新型蛋白将解决核酸治疗剂的释放不足的问题，因为鱼精蛋白会捕获这些核酸治疗剂用于 siRNA 的递送。TH 由组蛋白 H2A N 端序列的 4 个串联重复组成，中间插入组织蛋白酶 D 切割位点。重复的 H2A 序列增强了与阴离子核酸的结合亲和力，形成更稳定的凝聚物，如结合亲和力测定所示。TH/siRNA 凝聚物被制成具有核-膜结构的脂质体纳米颗粒（NP）。癌细胞的内体富含组织蛋白酶 D，允许 TH 在原位降解，促进 siRNA 的细胞内释放。与使用鱼精蛋白作为核酸缩合剂组装的 NP 相比，与 TH 组装的 NPs 在体外和体内对靶基因的沉默效率更高。TH 在 NP 配方中的应用表现出与鱼精蛋白相似的生物相容性特征，在重复给药后观察到最小的免疫刺激和全身毒性。
