Ciobanasu Corina, Dragomir Isabela, Apetrei Aurelia
Institute for Interdisciplinary Research, Science Research Department, Alexandru I. Cuza University, Iaşi, Romania.
Department of Physics, Alexandru I. Cuza University, Iasi, Romania.
J Pept Sci. 2019 Mar;25(3):e3145. doi: 10.1002/psc.3145. Epub 2018 Dec 27.
Cell-penetrating peptides (CPPs) have the property to cross the plasma membrane and enhance its permeability. CPPs were successfully used to deliver numerous cargoes such as drugs, proteins, nucleic acids, imaging and radiotherapeutic agents, gold and magnetic nanoparticles, or liposomes inside cells. Although CPPs were intensively investigated over the past 20 years, the exact molecular mechanisms of translocation across membranes are still controversial and vary from passive to active mechanisms. LyP-1 is a cyclic 9-amino-acids homing peptide that specifically binds to p32 receptors overexpressed in tumor cells. tLyP-1 peptide is the linear truncated form of LyP-1 and recognizes neuropilin (NRP) receptors expressed in glioma tumor tissue. Here, we investigate the interaction of the cyclic LyP-1 peptide and linear truncated tLyP-1 peptide with model plasma membrane in order to understand their passive, energy-independent mechanism of uptake. The experiments reveal that internalization of tLyP-1 peptides depends on membrane lipid composition. Inclusion of negatively charged phosphatidylserine (PS) or cone-shaped phosphatidylethanolamine (PE) lipids in the composition of giant unilamellar vesicles facilitates the membrane adsorption and direct penetration but without inducing pore formation in membranes. In contrast, cyclic LyP-1 peptide mostly accumulates on the membrane, with very low internalization, regardless of the lipid composition. Thus, the linear tLyP-1 peptide has enhanced penetrating properties compared with the cyclic LyP-1 peptide. Development of a mutant peptide containing higher number of arginine amino acids and preserving the homing properties of tLyP-1 may be a solution for new permeable peptides that facilitate the internalization in cells and further the endosomal escape as well.
细胞穿透肽（CPPs）具有穿过质膜并增强其通透性的特性。CPPs已成功用于在细胞内递送多种物质，如药物、蛋白质、核酸、成像和放射治疗剂、金和磁性纳米颗粒或脂质体。尽管在过去20年中对CPPs进行了深入研究，但跨膜转运的确切分子机制仍存在争议，涵盖从被动到主动的多种机制。LyP-1是一种环状九氨基酸归巢肽，它特异性结合在肿瘤细胞中过表达的p32受体。tLyP-1肽是LyP-1的线性截短形式，可识别在胶质瘤肿瘤组织中表达的神经纤毛蛋白（NRP）受体。在此，我们研究环状LyP-1肽和线性截短的tLyP-1肽与模型质膜的相互作用，以了解它们被动的、不依赖能量的摄取机制。实验表明，tLyP-1肽的内化取决于膜脂质组成。在巨型单层囊泡的组成中包含带负电荷的磷脂酰丝氨酸（PS）或锥形磷脂酰乙醇胺（PE）脂质有助于膜吸附和直接穿透，但不会在膜中诱导形成孔。相比之下，无论脂质组成如何，环状LyP-1肽大多积聚在膜上，内化程度非常低。因此，与环状LyP-1肽相比，线性tLyP-1肽具有更强的穿透特性。开发一种含有更多精氨酸氨基酸且保留tLyP-1归巢特性的突变肽，可能是开发新型可渗透肽的一种解决方案，这种肽有助于细胞内化以及进一步实现内体逃逸。
