IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France.
IRSD, Université de Toulouse, INSERM, INRAE, ENVT, UPS, Toulouse, France
mSphere. 2020 Dec 16;5(6):e01195-20. doi: 10.1128/mSphere.01195-20.
Colibactin induces DNA damage in mammalian cells and has been linked to the virulence of and the promotion of colorectal cancer (CRC). By looking for mutants attenuated in the promoter activity of encoding one of the key enzymes for the production of colibactin, we found that a mutant of the gene coding for the polyphosphate kinase (PPK) produced less colibactin than the parental strain. We observed this phenotype in different strains ranging from pathogens responsible for meningitis, urinary tract infection, or mouse colon carcinogenesis to the probiotic Nissle 1917. We confirmed the role of PPK by using an inhibitor of PPK enzymatic activity, mesalamine (also known as 5-aminosalicylic acid). Interestingly, mesalamine has a local anti-inflammatory effect on the epithelial cells of the colon and is used to treat inflammatory bowel disease (IBD). Upon treatment with mesalamine, a decreased genotoxicity of colibactin-producing was observed both on epithelial cells and directly on purified DNA. This demonstrates the direct effect of mesalamine on bacteria independently from its anti-inflammatory effect on eukaryotic cells. Our results suggest that the mechanisms of action of mesalamine in treating IBD and preventing CRC could also lie in the inhibition of colibactin production. All in all, we demonstrate that PPK is required for the promoter activity of and the production of colibactin, which suggests that PPK is a promising target for the development of anticolibactin and antivirulence strategies. Colibactin-producing induces DNA damage in eukaryotic cells and promotes tumor formation in mouse models of intestinal inflammation. Recent studies have provided strong evidence supporting the causative role of colibactin in human colorectal cancer (CRC) progression. Therefore, it is important to understand the regulation of the production of this genotoxin. Here, we demonstrate that polyphosphate kinase (PPK) is required for the promoter activity of and the production of colibactin. Interestingly, PPK is a multifunctional player in bacterial virulence and stress responses and has been proposed as a new target for developing antimicrobial medicine. We observed inhibition of colibactin production by using a previously identified PPK inhibitor (i.e., mesalamine, an anti-inflammatory drug commonly prescribed for inflammatory bowel diseases). These data brought us a new perspective on the regulatory network of colibactin production and provided us a clue for the development of anticolibactin strategies for CRC treatment/prophylaxis.
产黏菌素诱导哺乳动物细胞的 DNA 损伤，与 毒力和促进结直肠癌 (CRC) 有关。通过寻找编码产生黏菌素的关键酶之一的 基因启动子活性减弱的突变体，我们发现编码多聚磷酸激酶 (PPK) 的基因的突变体产生的黏菌素比亲本菌株少。我们在不同的菌株中观察到这种表型，这些菌株包括引起脑膜炎、尿路感染或小鼠结肠癌的病原体，以及益生菌 Nissle 1917。我们通过使用 PPK 酶活性抑制剂（美沙拉嗪，也称为 5-氨基水杨酸）来证实 PPK 的作用。有趣的是，美沙拉嗪对结肠上皮细胞具有局部抗炎作用，用于治疗炎症性肠病 (IBD)。在用美沙拉嗪治疗后，在大肠黏菌素产生菌的上皮细胞和纯化的 DNA 上直接观察到细胞毒性降低。这表明美沙拉嗪直接作用于细菌，而与对真核细胞的抗炎作用无关。我们的结果表明，美沙拉嗪治疗 IBD 和预防 CRC 的作用机制也可能在于抑制黏菌素的产生。总之，我们证明 PPK 是 基因启动子活性和黏菌素产生所必需的，这表明 PPK 是开发抗黏菌素和抗病毒策略的有前途的靶标。产黏菌素的 诱导真核细胞的 DNA 损伤，并促进小鼠肠道炎症模型中的肿瘤形成。最近的研究提供了强有力的证据支持黏菌素在人类结直肠癌 (CRC) 进展中的因果作用。因此，了解这种遗传毒素产生的调节非常重要。在这里，我们证明多聚磷酸激酶 (PPK) 是 基因启动子活性和黏菌素产生所必需的。有趣的是，PPK 是细菌毒力和应激反应的多功能参与者，已被提议作为开发抗菌药物的新靶标。我们观察到使用先前鉴定的 PPK 抑制剂（即美沙拉嗪，一种常用于治疗炎症性肠病的抗炎药）抑制黏菌素的产生。这些数据为我们提供了产黏菌素调节网络的新视角，并为开发用于 CRC 治疗/预防的抗黏菌素策略提供了线索。
