RESUMEN

Antimicrobial resistance poses a significant threat to humanity, and the development of new antibiotics is urgently needed. Our research has focused on thiopeptide antibiotics such as micrococcin P2 (MP2) and derivatives thereof as new anti-infective agents. Thiopeptides are sulfur-rich, structurally complex substances that exhibit potent activity against Gram-positive pathogens and Mycobacteria species, including clinically resistant strains. The clinical development of thiopeptides has been hampered by the lack of efficient synthetic platforms to conduct detailed structure-activity relationship studies of these natural products. The present contribution touches upon efficient synthetic routes to MP2 that laid the groundwork for clinical translation. The medicinal chemistry campaign on MP2 has been guided by computational molecular dynamic simulations and parallel investigations to improve drug-like properties, such as enhancing the aqueous solubility and optimizing antibacterial activity. Such endeavors have enabled identification of promising lead compounds, AJ-037 and AJ-206, against Mycobacterium avium complex (MAC). Extensive in vitro studies revealed that these compounds exert potent activity against MAC species, a subspecies of non-tuberculous mycobacteria (NTM) that proliferate inside macrophages. Two additional pre-clinical candidates have been identified: AJ-024, for the treatment of Clostridioides difficile infections, and AJ-147, for methicillin-resistant Staphylococcus aureus impetigo. Both compounds compare quite favorably with current first-line treatments. In particular, the ability of AJ-147 to downregulate pro-inflammatory cytokines adds a valuable dimension to its clinical use. In light of above, these new thiopeptide derivatives are well-poised for further clinical development.

Asunto(s)

Antibacterianos , Bacteriocinas , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Antibacterianos/química , Bacteriocinas/farmacología , Bacteriocinas/química , Humanos , Relación Estructura-Actividad , Simulación de Dinámica Molecular , Péptidos/farmacología , Péptidos/química , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Clostridioides difficile/efectos de los fármacos

RESUMEN

Hydrogen sulfide (H2S) has emerged as an endogenous signaling molecule that functions in many physiological and pathological processes of human cells in health and disease, including neuromodulation and neuroprotection, inflammation, angiogenesis, and vasorelaxation. The limited clinical applications of current H2S donors have led to the development of H2S donor hybrid compounds that combine current H2S donors with bioactive molecules. Finely tuned multi-targeting hybrid molecules have been shown to have complementary neuroprotective effects against reactive oxygen species (ROS)-induced oxidative stress. In this study, we developed hybrid molecules combining a dithiolethione-based slow-releasing H2S donor that exerts neuroprotective effects, with the tripeptides glycyl-L-histidyl-l-lysine (GHK) and L-alanyl-L-cystinyl-l-glutamine (ACQ), two natural products that exhibit powerful antioxidant effects. In particular, a hybrid combination of a dithiolethione-based slow-releasing H2S donor and ACQ exhibited significant neuroprotective effects against glutamate-induced oxidative damage in HT22 hippocampal neuronal cells. This hybrid remarkably suppressed Ca2+ accumulation and ROS production. Furthermore, it efficiently inhibited apoptotic neuronal cell death by blocking apoptosis-inducing factor release and its translocation to the nucleus. These results indicate that the hybrid efficiently inhibited apoptotic neuronal cell damage by complementary neuroprotective actions.

Asunto(s)

Sulfuro de Hidrógeno , Fármacos Neuroprotectores , Humanos , Fármacos Neuroprotectores/farmacología , Especies Reactivas de Oxígeno/metabolismo , Estrés Oxidativo , Péptidos/farmacología , Hipocampo/metabolismo , Sulfuro de Hidrógeno/metabolismo

RESUMEN

The US Centers for Disease Control and Prevention (CDC) lists Clostridioides difficile as an urgent bacterial threat. Yet, only two drugs, vancomycin and fidaxomicin, are approved by the FDA for the treatment of C. difficile infections as of this writing, while the global pipeline of new drugs is sparse at best. Thus, there is a clear and urgent need for new antibiotics against that organism. Herein, we disclose that AJ-024, a nitroimidazole derivative of a 26-membered thiopeptide, is a promising anti-C. difficile lead compound. Despite their unique mode of action, thiopeptides remain largely unexploited as anti-infective agents. AJ-024 combines potent in vitro activity against various strains of C. difficile with a noteworthy safety profile and desirable pharmacokinetic properties. Its time-kill kinetics against a hypervirulent C. difficile ribotype 027 and in vivo (mouse) efficacy compare favorably to vancomycin, and they define AJ-024 as a valuable platform for the development of new anti-C. difficile antibiotics.