为了提高β-环糊精(β-CD)-螺纹酸可降解聚轮烷(β-CDPRXs)在胆固醇相关代谢紊乱中的治疗潜力,我们研究了β-CDPRXs羧化对细胞内摄取的影响。在这项研究中,建立了羧基烷基氨基甲酸酯在β-CDPRXs上不降解修饰的合成方法,合成了三个系列具有不同烷基间隔长度的羧基烷基氨基甲酸酯基团修饰的β-CDPRXs。羧甲基氨基甲酸酯(CMC)的改性,羧基乙基氨基甲酸酯(CEC),与2-(2-羟基乙氧基)氨基甲酸乙酯(HEE-PRX)的修饰相比,β-CDPRX上的羧基丙基氨基甲酸酯(CPC)略微降低了PRX与脂质层模型的相互作用,这是在我们以前的研究中使用的。然而,与HEE-PRX相比,所有羧化β-CDPRX与蛋白模型的相互作用明显更强.羧化β-CDPRX显示显著高的细胞内摄取,通过巨噬细胞清道夫受体A(MSR-A)介导的内吞作用,在MSR-A阳性RAW264.7细胞中与HEE-PRX相比。有趣的是,与HEE-PRX相比,即使在MSR-A阴性细胞中,羧化β-CDPRX也显示出明显更高的细胞内摄取。羧基化β-CDPRX被认为与其他膜蛋白强烈相互作用,导致高的细胞内摄取。烷基间隔区的长度影响羧化PRX的细胞内摄取水平,然而,这种关系对于不同的细胞类型是不同的。此外,在RAW264.7和NIH/3T3细胞中没有一个羧化的β-CDPRX表现出细胞毒性。总之,β-CDPRX的羧化是用于其治疗应用的有前途的化学修饰方法,因为羧化的β-CDPRX在MSR-A阴性细胞中表现出高的细胞内化效率和可忽略的毒性。
To improve the therapeutic potential of β-cyclodextrin (β-CD)-threaded acid-degradable polyrotaxanes (β-CD PRXs) in cholesterol-related metabolic disorders, we investigated the effect of carboxylation of β-CD PRXs on intracellular uptake. In this study, we established a synthetic method for the modification of carboxylalkyl carbamates on β-CD PRXs without degradation and synthesized three series of carboxyalkyl carbamate group-modified β-CD PRXs with different alkyl spacer lengths. The modification of carboxymethyl carbamate (CMC), carboxyethyl carbamate (CEC), and carboxypropyl carbamate (CPC) on the β-CD PRXs slightly reduced the interaction of the PRXs with the lipid layer model compared with the modification of 2-(2-hydroxyethoxy)ethyl carbamate (HEE-PRX), which was used in our previous studies. However, all the carboxylated β-CD PRXs showed a significantly stronger interaction with a protein model compared with HEE-PRX. The carboxylated β-CD PRXs showed significantly high intracellular uptake, through macrophage scavenger receptor A (MSR-A)-mediated endocytosis, in MSR-A-positive RAW 264.7 cells compared with HEE-PRX. Interestingly, the carboxylated β-CD PRXs also showed significantly higher intracellular uptake even in MSR-A-negative cells compared with HEE-PRX. Carboxylated β-CD PRXs are considered to strongly interact with other membrane proteins, resulting in high intracellular uptake. The length of the alkyl spacer affected the intracellular uptake levels of carboxylated PRXs, however, this relationship was varied for different cell types. Furthermore, none of the carboxylated β-CD PRXs exhibited cytotoxicity in the RAW 264.7 and NIH/3T3 cells. Altogether, carboxylation of β-CD PRXs is a promising chemical modification approach for their therapeutic application because carboxylated β-CD PRXs exhibit high cellular internalization efficiency in MSR-A-negative cells and negligible toxicity.