二氟甲基鸟氨酸(DFMO)和 AMXT1501 抑制肺炎球菌荚膜生物合成。
Difluoromethylornithine (DFMO) and AMXT 1501 inhibit capsule biosynthesis in pneumococci.
机构信息
Department of Comparative Biomedical Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA.
Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, USA.
出版信息
Sci Rep. 2022 Jul 12;12(1):11804. doi: 10.1038/s41598-022-16007-7.
Polyamines are small cationic molecules that have been linked to various cellular processes including replication, translation, stress response and recently, capsule regulation in Streptococcus pneumoniae (Spn, pneumococcus). Pneumococcal-associated diseases such as pneumonia, meningitis, and sepsis are some of the leading causes of death worldwide and capsule remains the principal virulence factor of this versatile pathogen. α-Difluoromethyl-ornithine (DFMO) is an irreversible inhibitor of the polyamine biosynthesis pathway catalyzed by ornithine decarboxylase and has a long history in modulating cell growth, polyamine levels, and disease outcomes in eukaryotic systems. Recent evidence shows that DFMO can also target arginine decarboxylation. Interestingly, DFMO-treated cells often escape polyamine depletion via increased polyamine uptake from extracellular sources. Here, we examined the potential capsule-crippling ability of DFMO and the possible synergistic effects of the polyamine transport inhibitor, AMXT 1501, on pneumococci. We characterized the changes in pneumococcal metabolites in response to DFMO and AMXT 1501, and also measured the impact of DFMO on amino acid decarboxylase activities. Our findings show that DFMO inhibited pneumococcal polyamine and capsule biosynthesis as well as decarboxylase activities, albeit, at a high concentration. AMXT 1501 at physiologically relevant concentration could inhibit both polyamine and capsule biosynthesis, however, in a serotype-dependent manner. In summary, this study demonstrates the utility of targeting polyamine biosynthesis and transport for pneumococcal capsule inhibition. Since targeting capsule biosynthesis is a promising way for the eradication of the diverse and pathogenic pneumococcal strains, future work will identify small molecules similar to DFMO/AMXT 1501, which act in a serotype-independent manner.
多胺是小分子阳离子,与多种细胞过程有关,包括复制、翻译、应激反应,最近还与肺炎链球菌(Spn,肺炎球菌)的荚膜调节有关。肺炎球菌相关疾病,如肺炎、脑膜炎和败血症,是全球一些主要的死亡原因,荚膜仍然是这种多功能病原体的主要毒力因子。α-二氟甲基鸟氨酸(DFMO)是鸟氨酸脱羧酶催化的多胺生物合成途径的不可逆抑制剂,在调节真核系统中的细胞生长、多胺水平和疾病结果方面有着悠久的历史。最近的证据表明,DFMO 还可以靶向精氨酸脱羧酶。有趣的是,DFMO 处理的细胞通常通过从细胞外来源增加多胺摄取来逃避多胺耗竭。在这里,我们研究了 DFMO 潜在的荚膜削弱能力以及多胺转运抑制剂 AMXT 1501 对肺炎球菌的可能协同作用。我们描述了肺炎球菌代谢物对 DFMO 和 AMXT 1501 的反应变化,还测量了 DFMO 对氨基酸脱羧酶活性的影响。我们的研究结果表明,DFMO 抑制了肺炎球菌多胺和荚膜的生物合成以及脱羧酶活性,但需要高浓度。在生理相关浓度下,AMXT 1501 可以抑制多胺和荚膜的生物合成,但具有血清型依赖性。总之,这项研究表明,针对多胺生物合成和运输来抑制肺炎球菌荚膜是可行的。由于针对荚膜生物合成是消除多种致病性肺炎球菌菌株的有前途的方法,未来的工作将确定类似于 DFMO/AMXT 1501 的小分子,它们以与血清型无关的方式发挥作用。