Department of Chemistry & Biochemistry, University of California San Diego, 9500 Gilman Drive, CA, 92093, La Jolla, United States.
Department of Chemistry, Hamilton College, 198 College Hill Road, NY 13323, Clinton, United States.
Chemistry. 2022 Jan 24;28(5):e202103438. doi: 10.1002/chem.202103438. Epub 2021 Dec 16.
Recently, we presented a strategy for packaging peptides as side-chains in high-density brush polymers. For this globular protein-like polymer (PLP) formulation, therapeutic peptides were shown to resist proteolytic degradation, enter cells efficiently and maintain biological function. In this paper, we establish the role charge plays in dictating the cellular uptake of these peptide formulations, finding that peptides with a net positive charge will enter cells when polymerized, while those formed from anionic or neutral peptides remain outside of cells. Given these findings, we explored whether cellular uptake could be selectively induced by a stimulus. In our design, a cationic peptide is appended to a sequence of charge-neutralizing anionic amino acids through stimuli-responsive cleavable linkers. As a proof-of-concept study, we tested this strategy with two different classes of stimuli, exogenous UV light and an enzyme (a matrix metalloproteinase) associated with the inflammatory response. The key finding is that these materials enter cells only when acted upon by the stimulus. This approach makes it possible to achieve delivery of the polymers, therapeutic peptides or an appended cargo into cells in response to an appropriate stimulus.
最近，我们提出了一种将肽作为侧链包装在高密度刷状聚合物中的策略。对于这种类似球状蛋白的聚合物（PLP）制剂，研究表明治疗性肽能抵抗蛋白水解降解，有效地进入细胞并保持生物功能。在本文中，我们确定了电荷在决定这些肽制剂的细胞摄取中的作用，发现当聚合物化时带有净正电荷的肽会进入细胞，而由阴离子或中性肽形成的肽则留在细胞外。基于这些发现，我们探讨了细胞摄取是否可以通过刺激选择性地诱导。在我们的设计中，通过响应性可切割连接子将阳离子肽附加到电荷中和的阴离子氨基酸序列上。作为概念验证研究，我们用两种不同类型的刺激物（外源性紫外光和与炎症反应相关的酶（基质金属蛋白酶））测试了这种策略。关键发现是，只有在受到刺激时，这些材料才会进入细胞。这种方法使得有可能在适当的刺激下实现聚合物、治疗性肽或附加货物的递送到细胞中。
