Tan-No K, Cebers G, Yakovleva T, Hoon Goh B, Gileva I, Reznikov K, Aguilar-Santelises M, Hauser K F, Terenius L, Bakalkin G
Section of Alcohol and Drug Addiction Research, Karolinska Institute, S-171 76 Stockholm, Sweden.
Exp Cell Res. 2001 Sep 10;269(1):54-63. doi: 10.1006/excr.2001.5309.
Dynorphin A, a prodynorphin-derived peptide, is able to induce neurological dysfunction and neuronal death. To study dynorphin cytotoxicity in vitro, prodynorphin-derived peptides were added into the culture medium of nonneuronal and neuronal cells or delivered into these cells by lipofection or electroporation. Cells were unaffected by extracellular exposure when peptides were added to the medium. In contrast, the number of viable cells was significantly reduced when dynorphin A or "big dynorphin," consisting of dynorphins A and B, was transfected into cells. Big dynorphin was more potent than dynorphin A, whereas dynorphin B; dynorphin B-29; [Arg(11,13)]-dynorphin A(-13)-Gly-NH-(CH(2))(5)-NH(2), a selective kappa-opioid receptor agonist; and poly-l-lysine, a basic peptide more positively charged than big dynorphin, failed to affect cell viability. The opioid antagonist naloxone did not prevent big dynorphin cytotoxicity. Thus, the toxic effects were structure selective but not mediated through opioid receptors. When big dynorphin was delivered into cells by lipofection, it became localized predominantly in the cytoplasm and not in the nuclei. Big dynorphin appeared to induce toxicity through an apoptotic mechanism that may involve synergistic interactions with the p53 tumor-suppressor protein. It is proposed that big dynorphin induces cell death by virtue of its net positive charge and clusters of basic amino acids that mimic (and thereby perhaps interfere with) basic domains involved in protein-protein interactions. These effects may be relevant for a pathophysiological role of dynorphins in the brain and spinal cord and for control of death of tumor cells, which express prodynorphin at high levels.
强啡肽A是一种源自前强啡肽的肽，能够诱发神经功能障碍和神经元死亡。为了在体外研究强啡肽的细胞毒性，将源自前强啡肽的肽添加到非神经元细胞和神经元细胞的培养基中，或者通过脂质转染或电穿孔法将其导入这些细胞。当将肽添加到培养基中时，细胞不受细胞外暴露的影响。相比之下，当将强啡肽A或由强啡肽A和B组成的“大强啡肽”转染到细胞中时，活细胞数量显著减少。大强啡肽比强啡肽A更具效力，而强啡肽B、强啡肽B-29、[精氨酸(11,13)]-强啡肽A(-13)-甘氨酰胺-(CH₂)₅-NH₂（一种选择性κ阿片受体激动剂）以及聚-L-赖氨酸（一种比大强啡肽带更多正电荷的碱性肽）均未影响细胞活力。阿片拮抗剂纳洛酮不能预防大强啡肽的细胞毒性。因此，毒性作用具有结构选择性，但并非通过阿片受体介导。当通过脂质转染将大强啡肽导入细胞时，它主要定位于细胞质而非细胞核。大强啡肽似乎通过一种凋亡机制诱导毒性，该机制可能涉及与p53肿瘤抑制蛋白的协同相互作用。有人提出，大强啡肽因其净正电荷和碱性氨基酸簇而诱导细胞死亡，这些碱性氨基酸簇模拟（从而可能干扰）参与蛋白质-蛋白质相互作用的碱性结构域。这些作用可能与强啡肽在脑和脊髓中的病理生理作用以及对高水平表达前强啡肽的肿瘤细胞死亡的控制有关。
