Cell-penetrating peptides (CPPs) can deliver payloads into cells by forming complexes with bioactive molecules via either covalent or non-covalent bonds. Previously, we reported polyhistidine (H16 peptide: HHHHHHHHHHHHHHHH-NH₂) as a new CPP. This peptide is anticipated to be a valuable new carrier for drug delivery to intracellular lysosomes; the peptide can transport macromolecules into these organelles. In the present study, we examined the application of the H16 peptide as a drug delivery system (DDS) to reverse to lysosomal storage disease (LSD) in cells in vitro. LSDs are metabolic disorders caused by the loss of specific lysosomal enzymes. The majority of lysosomal enzymes are acidic proteins and we utilized this common feature for our DDS. We synthesized a polylysine–polyhistidine fusion peptide (K10H16 peptide: KKKKKKKKKKGHHHHHHHHHHHHHHHH-NH₂) and developed a simple method for transporting acidic proteins into intracellular lysosomes via formation of complexes of enzymes with the K10H16 peptide by electrostatic interaction. First, we demonstrated our strategy using maltose-binding protein-fused green fluorescent protein (MBP–GFP) to model an acidic protein. The K10H16 peptide bound to MBP–GFP and transported it into intracellular lysosomes. Further, alpha-galactosidase A (GLA), one of the lysosomal enzymes associated with LSD, was also delivered to intracellular lysosomes by the peptide. The complex between K10H16 peptide and GLA restored typical proliferation to LSD cells, which otherwise grew more slowly than normal cells. These results suggest that K10H16 peptide replenished lysosomal enzyme deficiency in LSD cells. The K10H16 peptide may be useful as a DDS for LSD therapy.

细胞穿透肽（CPP）可以通过共价键或非共价键与生物活性分子形成复合物，从而将有效载荷传递到细胞中。以前，我们报道了多组氨酸（H16肽：HHHHHHHHHHHHHHHHHHH-NH ₂）作为新的CPP。预期该肽是用于药物递送至细胞内溶酶体的有价值的新载体。肽可以将大分子转运到这些细胞器中。在本研究中，我们研究了H16肽作为药物传递系统（DDS）在体外逆转溶酶体贮积病（LSD）的应用。LSD是由特异性溶酶体酶的损失引起的代谢性疾病。大多数溶酶体酶是酸性蛋白，我们在DDS中利用了这一共同特征。我们合成了聚赖氨酸-聚组氨酸融合肽（肽K10H16：KKKKKKKKKKGHHHHHHHHHHHHHHHH-NH ₂）和开发了一种简单的方法用于输送酸性蛋白质进入细胞内溶酶体通过形成与通过静电相互作用的K10H16肽酶复合物的。首先，我们展示了使用麦芽糖结合蛋白融合的绿色荧光蛋白（MBP – GFP）建模酸性蛋白的策略。与MBP结合的K10H16肽–GFP并将其转运到细胞内溶酶体中。此外，α-半乳糖苷酶A（GLA），一种与LSD相关的溶酶体酶，也被该肽递送至细胞内溶酶体。K10H16肽和GLA之间的复合物恢复了LSD细胞的典型增殖，否则LSD细胞的生长将比正常细胞慢。这些结果表明，K10H16肽补充了LSD细胞中的溶酶体酶缺乏症。K10H16肽可用作LSD治疗的DDS。