Chuard Nicolas, Poblador-Bahamonde Amalia I, Zong Lili, Bartolami Eline, Hildebrandt Jana, Weigand Wolfgang, Sakai Naomi, Matile Stefan
Department of Organic Chemistry , University of Geneva , Geneva , Switzerland . Email:
Institute of Inorganic and Analytical Chemistry , Friedrich-Schiller University Jena , Germany.
Chem Sci. 2018 Jan 17;9(7):1860-1866. doi: 10.1039/c7sc05151d. eCollection 2018 Feb 21.
The emerging power of thiol-mediated uptake with strained disulfides called for a move from sulfur to selenium. We report that according to results with fluorescent model substrates, cellular uptake with 1,2-diselenolanes exceeds uptake with 1,2-dithiolanes and epidithiodiketopiperazines with regard to efficiency as well as intracellular localization. The diselenide analog of lipoic acid performs best. This 1,2-diselenolane delivers fluorophores efficiently to the cytosol of HeLa Kyoto cells, without detectable endosomal capture as with 1,2-dithiolanes or dominant escape into the nucleus as with epidithiodiketopiperazines. Diselenolane-mediated cytosolic delivery is non-toxic (MTT assay), sensitive to temperature but insensitive to inhibitors of endocytosis (chlorpromazine, methyl-β-cyclodextrin, wortmannin, cytochalasin B) and conventional thiol-mediated uptake (Ellman's reagent), and to serum. Selenophilicity, the extreme CSeSeC dihedral angle of 0° and the high but different acidity of primary and secondary selenols might all contribute to uptake. Thiol-exchange affinity chromatography is introduced as operational mimic of thiol-mediated uptake that provides, in combination with rate enhancement of DTT oxidation, direct experimental evidence for existence and nature of the involved selenosulfides.
硫醇介导的含张力二硫化物摄取的新兴力量促使人们从硫转向硒。我们报告称，根据荧光模型底物的结果，就效率以及细胞内定位而言，1,2-二硒戊环的细胞摄取超过了1,2-二硫戊环和环二硫代二酮哌嗪。硫辛酸的二硒化物类似物表现最佳。这种1,2-二硒戊环能将荧光团高效递送至HeLa Kyoto细胞的细胞质中，不会像1,2-二硫戊环那样被检测到内体捕获，也不会像环二硫代二酮哌嗪那样大量逃逸到细胞核中。二硒戊环介导的细胞质递送无毒（MTT法），对温度敏感，但对内吞作用抑制剂（氯丙嗪、甲基-β-环糊精、渥曼青霉素、细胞松弛素B）、传统硫醇介导的摄取（埃尔曼试剂）和血清不敏感。亲硒性、0°的极端CSeSeC二面角以及伯硒醇和仲硒醇的高酸度但不同的酸度可能都有助于摄取。引入硫醇交换亲和色谱作为硫醇介导摄取的操作模拟，结合二硫苏糖醇氧化速率的提高，为所涉及的硒硫化物的存在和性质提供了直接的实验证据。
