A multivalent peptide library approach identifies a novel Shiga toxin inhibitor that induces aberrant cellular transport of the toxin
A multivalent peptide library approach identifies a novel Shiga toxin inhibitor that induces aberrant cellular transport of the toxin
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DOI：
10.1096/fj.06-6572fje
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发表时间：
2006-12-01
期刊：
影响因子：
4.8
通讯作者：
Natori, Yasuhiro
中科院分区：
文献类型：
--
作者：
Nishikawa, Kiyotaka;Watanabe, Miho;Natori, Yasuhiro
感染产滋贺毒素（Stx）的大肠杆菌O 157：H7可引起人类出血性腹泻和出血性结肠炎，有时会导致致命的全身并发症。在已知的Stx家族成员中，Stx 2是导致最严重疾病的原因。Stx 2通过其B亚基五聚体和globotriaosyl神经酰胺之间的多价相互作用结合靶细胞。结合后，它首先逆行转运到高尔基体，然后转运到内质网（ER）。使用多价肽库的方法，我们确定了四价肽，表现出高亲和力的Stx 2 B-亚基五聚体（KD = 0.13 μ M），并显着抑制Stx 2细胞毒性。四价肽通过诱导Stx 2的异常细胞转运发挥其抑制作用。虽然四价肽/Stx 2复合物被纳入细胞和易位到高尔基体，这个过程之后的有效降解Stx 2在酸性区室，而不是通过其转移到ER。这种肽完全保护小鼠免受致命剂量的E。大肠杆菌O 157：H7，即使在建立感染后给药。因此，多价肽文库方法使得能够鉴定基于肽的Stx 2抑制剂，其具有显著的治疗效力并且似乎通过诱导Stx 2的异常细胞转运和降解而起作用。
Infection with Shiga toxin (Stx)-producing Escherichia coli O157:H7 causes bloody diarrhea and hemorrhagic colitis in humans, sometimes resulting in fatal systemic complications. Among the known Stx family members, Stx2 is responsible for the most severe forms of disease. Stx2 binds to target cells via multivalent interactions between its B-subunit pentamer and globotriaosyl ceramide. After binding, it is first retrogradely transported to the Golgi and then to the endoplasmic reticulum (ER). Using a multivalent peptide library approach, we identified a tetravalent peptide that exhibits a high affinity for the Stx2 B-subunit pentamer (K-D = 0.13 mu M) and markedly inhibits Stx2 cytotoxicity. The tetravalent peptide exerted its inhibitory effects by inducing aberrant cellular transport of Stx2. Although the tetravalent peptide/Stx2 complex was incorporated into cells and translocated to the Golgi, this process was followed by the effective degradation of Stx2 in an acidic compartment rather than by its transfer to the ER. This peptide thoroughly protected mice from a fatal dose of E. coli O157:H7 even when administered after an established infection. Thus, the multivalent peptide library approach enabled the identification of a peptide-based Stx2 inhibitor that has remarkable therapeutic potency and appears to function by inducing aberrant cellular transport and degradation of Stx2.