Wang Wei, Wu Sudong, Wang Jingyun, Li Zhen, Cui Hongyan, Lin Shuseng, Zhu Jingyi, Chen Qixian
State Key Laboratory of Fine Chemicals , Dalian University of Technology , No. 2 Linggong Road , Dalian 116024 , China . Email:
School of Life Science and Biotechnology , Dalian University of Technology , No. 2 Linggong Road , Dalian 116024 , China.
Chem Sci. 2019 Mar 11;10(16):4476-4485. doi: 10.1039/c8sc04160a. eCollection 2019 Apr 28.
The development of molecular biology has led to the identification of protein-based therapeutics as an intriguing approach for the treatment of a wide range of diseases. To manufacture transcellular protein delivery shuttles, we attempted charge reversal chemistry on native proteins [, superoxide dismutase (SOD): an enzyme capable of scavenging detrimental reactive oxygen species] by the selective conversion of the positively charged amino residues of native SOD to conjugated negatively charged citraconic moieties, eliciting overall negatively charged polyelectrolytes for the subsequent electrostatic self-assembly with cationic metal-organic framework (MOF) derivatives into protein delivery systems. Please note that the charge conversion was reversible, restoring the original amino groups in intracellular acidic endosome compartments (pH 5), which afforded facile charge reversible functions to reclaim the active SOD in the cell interior. In particular, the strategic manufacture of dendritic MOF supramolecular architectures as transcellular shuttles for the aforementioned charge-reversible SOD derivatives is noteworthy. The MOF was surface-functionalized with several polycationic segments, thus contributing to the hyper-charged architecture for the easy accommodation of the negatively charged SOD derivatives. Consequently, the SOD derivatives managed to internalize into cells by hitchhiking endocytosis of the positively charged MOF. Once they resided in the acidic endosomes, the charge reversal of the SOD derivatives could occur smoothly and result in reduced interactions between the charged-reversed SOD and MOF, leading to the release of active SOD. Simultaneously, the dendritic MOF due to protein release presented a highly positive-charged architecture to provoke endosome membrane disruption, consequently spurring the translocation of SOD to the cytosol for the execution of its enzymatic activities. Herein, the intracellular ROS level of the activated macrophages was validated to be markedly suppressed by our proposed transcellular SOD shuttles, thereby indicating their wide availability to diverse functional proteins for biomedical applications.
分子生物学的发展使基于蛋白质的疗法成为治疗多种疾病的一种引人关注的方法。为了制造跨细胞蛋白质递送载体，我们尝试通过将天然超氧化物歧化酶（SOD，一种能够清除有害活性氧的酶）带正电荷的氨基残基选择性转化为共轭的带负电荷的柠康酸部分，对天然蛋白质进行电荷反转化学修饰，从而产生带负电荷的聚电解质，以便随后与阳离子金属有机框架（MOF）衍生物进行静电自组装形成蛋白质递送系统。请注意，电荷转化是可逆的，在细胞内酸性内涵体区室（pH 5）中恢复原始氨基，这赋予了便捷的电荷可逆功能，以便在细胞内部回收活性SOD。特别值得注意的是，作为上述电荷可逆SOD衍生物的跨细胞载体，树枝状MOF超分子结构的策略性制造。MOF用几个聚阳离子片段进行表面功能化，从而形成高电荷结构，便于容纳带负电荷的SOD衍生物。因此，SOD衍生物通过搭乘带正电荷MOF的内吞作用进入细胞。一旦它们位于酸性内涵体中，SOD衍生物的电荷反转可以顺利发生，并导致电荷反转后的SOD与MOF之间的相互作用减少，从而释放活性SOD。同时，由于蛋白质释放，树枝状MOF呈现出高正电荷结构，引发内涵体膜破裂，并因此促使SOD转运到细胞质中以执行其酶活性。在此，我们提出的跨细胞SOD载体被证实可显著抑制活化巨噬细胞的细胞内ROS水平，从而表明它们在生物医学应用中对多种功能蛋白具有广泛适用性。
