作者: Meyers, David J. ; Ranjit, Arina ; Bockley, Kimberly M. ; Rais, Rana ; Ensign, Laura M. ; Serrano-Diaz, Erika ; Freel Meyers, Caren L. ; Paule, James ; DeColli, Alicia A.

ABSTRACT:

Metabolic processes required for bacterial pathogens to adapt in the host are potential targets for the development of much-needed new antimicrobial agents. The bacterial central metabolic enzyme 1-deoxy- d -xylulose 5-phosphate synthase (DXPS) is required for the synthesis of essential isoprenoids, thiamin diphosphate (ThDP), and pyridoxal phosphate (PLP) and is believed to function in bacterial adaptations requiring these metabolites. DXPS inhibition impairs a PLP-dependent adaptation of Uropathogenic Escherichia coli (UPEC) to d -serine, a bacteriostatic host metabolite in urine that inhibits pantothenate production in Coenzyme A (CoA) biosynthesis. CoA is required for a functioning tricarboxylic acid (TCA cycle, which is critical for UPEC survival in the urinary tract. Accordingly, inhibition of DXPS also sensitizes UPEC to N -pentylpantothenamide (N5-Pan, 1 ), an inhibitor of CoA synthesis. However, 1 is enzymatically hydrolyzed by pantetheinases, presenting challenges for its use in in vivo studies. We sought to identify a pantothenamide inhibitor candidate for studies to explore the in vivo efficacy of inhibitor combinations targeting DXPS and CoA syntheses. Here, we describe studies that highlight a truncated analog of 1 , pantetheinase-resistant N5-α-Pan ( 6 ), as a promising candidate for in vivo studies. Analog 6 exhibited comparable antimicrobial activity with 1 against UPEC grown in nutrient-limited culture conditions, including urine, and displayed enhanced activity in the presence of a DXPS inhibitor. In contrast to 1 , analog 6 was stable in the presence of mouse plasma and liver enzymes, making it suitable for studies to investigate an inhibitor combination targeting DXPS and CoA synthesis in UPEC by the in vivo ascending UTI assay.

IMPORTANCE:

New approaches are needed to control the emergence of drug resistance in bacterial pathogens that cause life-threatening infections. Targeting DXPS-dependent synthesis of vitamins is a promising approach to prevent pathogen metabolic adaptation. Metabolic processes requiring DXPS-dependent synthesis of pyridoxal phosphate (PLP) or thiamin diphosphate (ThDP) can become particularly vulnerable in a specific pathogen and/or host environment, under conditions of DXPS inhibition. We previously observed that UPEC grown in urine is particularly sensitive to an inhibitor combination targeting DXPS and CoA synthesis; however, the CoA inhibitor is readily hydrolyzed by a host pantetheinase. This study is significant, as it identifies a pantothenamide inhibitor of CoA synthesis, N5-α-Pan ( 6 ), that is stable to mouse plasma and liver enzymes and whose activity is enhanced in the presence of a DXPS inhibitor. Thus, 6 is suitable for studies to explore how a pathogen can become sensitized in vivo under conditions of DXPS inhibition.

2018-05-11·ACS infectious diseases2区 · 医学

Developing Pantetheinase-Resistant Pantothenamide Antibacterials: Structural Modification Impacts on PanK Interaction and Mode of Action

2区 · 医学

Article

作者: van Otterlo, Willem A. L. ; Barnard, Leanne ; Strauss, Erick ; Mostert, Konrad J.

Pantothenamides (PanAms) are analogues of pantothenate, the biosynthetic precursor of coenzyme A (CoA), and show potent antimicrobial activity against several bacteria and the malaria parasite in vitro. However, pantetheinase enzymes that normally degrade pantetheine in human serum also act on the PanAms, thereby reducing their potency. In this study, we designed analogues of the known antibacterial PanAm N-heptylpantothenamide (N7-Pan) to be resistant to pantetheinase by using three complementary structural modification strategies. We show that, while two of these are effective in imparting resistance, the introduced modifications have an impact on the analogues' interaction with pantothenate kinase (PanK, the first CoA biosynthetic enzyme), which acts as a metabolic activator and/or target of the PanAms. This, in turn, directly affects their mode of action. Importantly, we discover that the phosphorylated version of N7-Pan shows pantetheinase resistance and antistaphylococcal activity, providing a lead for future studies in the ongoing search of PanAm analogues that show in vivo efficacy.

2016-09-09·ACS infectious diseases2区 · 医学

Discovery of Potent Pantothenamide Inhibitors of Staphylococcus aureus Pantothenate Kinase through a Minimal SAR Study: Inhibition Is Due to Trapping of the Product

2区 · 医学

Article

作者: Park, Hee-Won ; Tempel, Wolfram ; Vedadi, Masoud ; Hong, Bum Soo ; Antoshchenko, Tetyana ; Barnard, Leanne ; Hughes, Scott J. ; Strauss, Erick ; Allali-Hassani, Abdellah ; Smil, David ; Mottaghi, Katayoun

The potent antistaphylococcal activity of N-substituted pantothenamides (PanAms) has been shown to at least partially be due to the inhibition of Staphylococcus aureus's atypical type II pantothenate kinase (SaPanK_II), the first enzyme of coenzyme A biosynthesis. This mechanism of action follows from SaPanK_II having a binding mode for PanAms that is distinct from those of other PanKs. To dissect the molecular interactions responsible for PanAm inhibitory activity, we conducted a mini SAR study in tandem with the cocrystallization of SaPanK_II with two classic PanAms (N5-Pan and N7-Pan), culminating in the synthesis and characterization of two new PanAms, N-Pip-PanAm and MeO-N5-PanAm. The cocrystal structures showed that all of the PanAms are phosphorylated by SaPanK_II but remain bound at the active site; this occurs primarily through interactions with Tyr240' and Thr172'. Kinetic analysis showed a strong correlation between k_cat (slow PanAm turnover) and IC₅₀ (inhibition of pantothenate phosphorylation) values, suggesting that SaPanK_II inhibition occurs via a delay in product release. In-depth analysis of the PanAm-bound structures showed that the capacity for accepting a hydrogen bond from the amide of Thr172' was a stronger determinant for PanAm potency than the capacity to π-stack with Tyr240'. The two new PanAms, N-Pip-PanAm and MeO-N5-PanAm, effectively combine both hydrogen bonding and hydrophobic interactions, resulting in the most potent SaPanK_II inhibition described to date. Taken together, our results are consistent with an inhibition mechanism wherein PanAms act as SaPanK_II substrates that remain bound upon phosphorylation. The phospho-PanAm-SaPanK_II interactions described herein may help future antistaphylococcal drug development.

项与 MMV-689258 相关的新闻（医药）

2024-11-29

·CPHI制药在线

抗疟疾药物研发进展

关注并星标CPHI制药在线在全球健康的版图中，疟疾一直是一块难以攻克的“顽疾”。据世界卫生组织（WHO）统计，2021年全球约有2.47亿疟疾病例，61.9万人因此失去生命，其中95%的病例和96%的死亡发生在撒哈拉以南非洲地区。疟疾不仅严重威胁人类健康，还对经济发展造成巨大阻碍，每年导致该地区约120亿美元的经济损失。今天，就让我们深入了解疟疾的现状、抗疟药物的研发进展，以及未来面临的挑战与希望。 1、现有抗疟疗法及耐药困境（1）常用药物与疗法当前，治疗非重症恶性疟原虫疟疾，主要依靠以青蒿素为基础的联合疗法（ACTs）。其中，蒿甲醚 - 苯芴醇（artemether lumefantrine，AL）在非洲市场占据了75%的份额，青蒿琥酯 - 阿莫地喹（artesunate amodiaquine）则作为二线选择，拥有24%的市场占有率。这些药物在一定程度上有效控制了疟疾的发展，但它们也面临着日益严峻的耐药问题。除了ACTs，还有双氢青蒿素 - 哌喹（dihydroartemisinin piperaquine，DHA - PPQ）、阿托伐醌 - 氯胍（atovaquone proguanil，Malarone）等药物组合，但使用相对较少。对于重症疟疾，静脉注射青蒿琥酯（artesunate）是首选治疗方法，金鸡纳霜（quinine）也可作为替代选择。而针对间日疟原虫疟疾的根治，氯喹（Chloroquine）与伯氨喹（primaquine）或他非诺喹（tafenoquine）的联合使用是常见方案；孕期间歇性预防治疗则采用磺胺多辛 - 乙胺嘧啶（sulfadoxine-pyrimethamine，SP）；在非洲的季节性疟疾高发地区，对于6个月至5岁（部分国家至10岁）的儿童，每月使用SP和阿莫地喹进行季节性疟疾化学预防（SMC）（图1）。（2）药物耐药性问题疟原虫耐药问题由来已久，20世纪初有对奎宁耐药的报告，50年代起氯喹和SP耐药性在疟疾流行区扩散，致死亡人数上升。21世纪ACTs虽为一线疗法，但耐药问题仍存。东南亚大部分地区DHA - PPQ因耐药失效，非洲大陆AL虽仍有效，但卢旺达已现青蒿素部分耐药，乌干达恶性疟原虫临床分离株对咯萘啶（pyronaridine）和DHA敏感性降低，这些耐药现象严重威胁全球疟疾防控成效。图1.在疟原虫生命周期下的疟疾治疗来源：出自参考文献【1】 2、抗疟药物研发进展（1）传统与现代的研发策略在抗疟药物研发的漫长历程中，传统策略主要包括从天然产物中分离和修饰活性成分，以及筛选化合物库、设计已知靶点抑制剂等。然而，这种基于天然产物的研发方式面临着诸多挑战，如供应不稳定、成分多变、生物测定引导分馏后复杂混合物相关的实际挑战。此外，对现有天然产物进行改进以克服耐药性的难度较大，这使得研发人员不得不寻求新的方法。随着科学技术的发展，现代抗疟药物研发主要采用表型筛选和基于靶点和虚拟药效团的方法。表型筛选：通过对全细胞寄生虫培养进行大规模化学库筛选，可发现具有新颖作用模式的化合物，许多在研药物由此发现，但靶点未知会给后续优化带来困难。基于靶点和虚拟药效团方法：基于靶点的方法可开发新的生化测定，合理设计化合物，但可能成本高且存在耐药风险；虚拟筛选虽初期成本低，但需大量后续工作确认化合物与靶点的结合及对寄生虫的功能抑制，目前尚未产生具有强细胞活性的新化合物。（2）新靶点及治疗药物为了开发更有效的抗疟药物，科学家们已经发现了一些具有潜力的靶点，如细胞色素B（CytB）、二氢蝶酸合成酶（DHPS）、二氢叶酸还原酶 - 胸苷酸合成酶（DHFR - TS）和血红素等，这些都是已有的临床验证靶点（图2）。此外，还有一些较新的靶点，如ATP酶4（ATP4）、延伸因子2（eEF2）、脯氨酰tRNA合成酶（PRS）和磷脂酰肌醇4 - 激酶（PI4K）等。图2.具有临床验证的抗疟靶点来源：出自参考文献【1】在抗疟药物的研发进程中，众多药物处于不同的研究阶段（图3），给我们带来了新的希望。患者探索阶段： ZY - 19489是一种快速杀伤无性血液阶段寄生虫且耐药倾向低的化合物，在志愿者感染研究中，其安全性、药代动力学和抗疟活性表现优异，支持其进一步开发。 ferroquine是一种含二茂铁基环的4 - 氨基喹啉类药物，具有快速杀伤和长半衰期的特点，与ZY - 19489组合使用，有望实现儿童疟疾的单剂量治疗，为应对ACTs耐药性提供了潜在解决方案。 cabamiquine对寄生虫无性肝、血和性阶段均有活性，但其耐药性发展较快，因此与咯萘啶联用，以增强疗效并延缓耐药性的产生。 ganaplacide对无性肝、血和性阶段的恶性疟原虫均有强效作用，与优化配方的苯芴醇联用，在临床研究中取得了积极结果，有望成为自2000年以来首个非ACT治疗药物。 cipargamin可使寄生虫僵化并快速清除，对传播阻断也有效，但由于存在耐药风险，目前正在探索注射用新配方，以确保其长期有效性。临床I期阶段： atoguanil是阿托伐醌 - 氯胍的新配方，旨在提高药物的疗效和安全性。 MMV688533是通过基于同源性的筛选策略发现的TCP - 1候选药物，其作用机制虽尚未完全明确，但耐药风险低，在实验室条件下难以产生耐药性，目前正在进行临床I期研究。 INE963是诺华发现的快速杀伤化合物，对无性血液阶段寄生虫具有高效作用，且耐药倾向低，近期已进入临床I期试验，后续还将在治疗组合的II期试验中进行评估。临床前阶段：共有11种候选小分子和1种抗体正在深入研究。其中， MMV183是一种抑制AcAS的抗代谢物，具有显著的传播阻断和无性血液阶段活性； GSK701是酰基辅酶A合成酶ACS10和ACS11的新型抑制剂，具有TCP - 1活性特征； WM382和BRD5018分别是 plasmepsins IX和X以及FRS的抑制剂，具有多阶段活性，对寄生虫的多个生命周期阶段均有作用； SC83288是一种新型注射候选药物，用于治疗重症疟疾，但其作用机制尚不清楚； GSK484和IWY357是通过表型筛选发现的快速杀伤化合物，具有低耐药倾向，虽然其结构和作用机制尚未公布，但在抗疟药物研发中具有潜在价值； MMV371是阿托伐醌前药，ELQ - 331是ELQ - 300的口服前药，两者均通过抑制寄生虫CytB发挥作用； S011 - 1793是下一代4 - 氨基喹啉，能够克服氯喹和PPQ耐药性； MMV1793609是PfATP4抑制剂，具有低剂量高效的特点，是2022年发现的备选药物。图3.抗疟药物研发进展和研发管线来源：出自参考文献【1】 3、抗疟之路的未来挑战与展望疟疾防控工作面临着诸多复杂的挑战，疟原虫耐药机制研究复杂，实验室研究多基于单基因变化，但实际临床分离株往往涉及多个突变，且寄生虫遗传背景对耐药性产生的影响机制尚不明确，不同地区疟原虫的遗传差异也导致耐药性表现和传播方式各异。此外，药物递送与药代动力学也存在难题，例如长效注射剂面临疗效持续时间、体积和安全性等挑战，不同人群对药物代谢和反应的差异也增加了研发复杂性...... 尽管挑战重重，但过去15年在疟疾防控方面取得了一定成果，新靶点不断被发现，候选药物进入研发管线，新治疗方法如首个疟疾疫苗获批问世。这些成绩的取得离不开全球各方的紧密合作，未来仍需进一步加强合作，整合资源、加大研发投入、鼓励创新，通过共享数据、技术和经验来加速抗疟药物研发进程，实现疟疾的有效控制和消除。疟疾防控是全球性持久战，每一次突破都使我们向战胜疟疾的目标更近一步，我们应共同关注和支持抗疟工作，期待人类能早日摆脱疟疾威胁。参考文献 [1]Siqueira-Neto, Jair L et al. “Antimalarial drug discovery: progress and approaches.” Nature reviews. Drug discovery vol. 22,10 (2023): 807-826. doi:10.1038/s41573-023-00772-9 [2]Carter, Richard, and Kamini N Mendis. “Evolutionary and historical aspects of the burden of malaria.” Clinical microbiology reviews vol. 15,4 (2002): 564-94. doi:10.1128/CMR.15.4.564-594.2002 [3]Rasmussen, Charlotte et al. “Current and emerging strategies to combat antimalarial resistance.” Expert review of anti-infective therapy vol. 20,3 (2022): 353-372. doi:10.1080/14787210.2021.1962291 END 【智药研习社近期直播预告】来源：CPHI制药在线声明：本文仅代表作者观点，并不代表制药在线立场。本网站内容仅出于传递更多信息之目的。如需转载，请务必注明文章来源和作者。投稿邮箱：Kelly.Xiao@imsinoexpo.com ▼更多制药资讯，请关注CPHI制药在线▼ 点击阅读原文，进入智药研习社~

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