ACS Infectious Diseases最新文献

Neutrophils, the first cells to arrive at infection sites, release neutrophil extracellular traps (NETs) comprising nuclear and/or mitochondrial DNA webs decorated with proteins. Similar to other parasites, Leishmania infantum induces NET extrusion. However, our understanding of NET formation and neutrophil fate after NET release in a Leishmania infection context is limited. Our study aimed to determine the DNA origin of the NET scaffolds released by human neutrophils in response to chemical or L. infantum stimulation. Neutrophils were incubated with PMA, PHA, LPS, or L. infantum, followed by DNA and elastase activity quantification; additionally, we evaluated the source of DNA that composes NETs. Neutrophil viability was evaluated by annexin-V/7AAd labeling. Expression of IL6, TNFA, IL10, CXCL1, CXCL8, and FPR1 in response to the L. infantum interaction was assessed. Neutrophils incubated with chemicals or L. infantum released NETs. However, neutrophils stimulated by the chemicals showed lower viability after 1 h in comparison to neutrophils incubated with parasites. NETs from chemically stimulated neutrophils were mainly composed of nuclear DNA. Conversely, the NET induced by the parasites was of mitochondrial DNA origin and had no leishmanicidal activity. After 4 h of parasite stimulation, neutrophils peak the expression of genes such as IL6, TNFA, CXCL1, CXCL8, and FPR1. Our study demonstrates that neutrophils produce NETs after chemical or L. infantum exposure. Although they are not toxic to the parasite, NETs are released as danger signals. These findings support the role of neutrophils in releasing signaling molecules, which influence the inflammatory environment in which the infectious process occurs.

Alphaviruses, a genus of vector-borne viruses in the Togaviridae family, encode a small ion-channel-forming protein, 6K, and its transframe variant (TF) during infections. Although 6K/TF have vital roles in glycoprotein transport, virus assembly, and budding, there is no mechanistic explanation for these functions. We investigated the distinct biochemical functionalities of 6K and TF from the mosquito-borne alphavirus, Chikungunya Virus. We show that like 6K, TF is also capable of forming ion channels in bilayer membranes. The assemblies formed by 6K in membranes are structurally more complex and potentially more ion-restrictive than those formed by TF. Both 6K and TF show strong affinity toward the ER membranes, indicating that the localization of these components at the plasma membrane, as previously reported, is either linked to post-translational modification or mediated through interaction with binding partners. These structural and functional insights may elucidate the distinct roles of 6K and TF in the alphavirus life cycle.

The type II NADH-dehydrogenase enzyme in Mycobacterium tuberculosis plays a critical role in the efficient functioning of the oxidative phosphorylation pathway. It acts as the entry point for electrons in the electron transport chain, which is essential for fulfilling the energy requirements of both replicating and nonreplicating mycobacterial species. Due to the absence of the type II NADH-dehydrogenase enzyme in mammalian mitochondria, targeting the type II NADH-dehydrogenase enzyme for antitubercular drug discovery could be a vigilant approach. Utilizing type II NADH-dehydrogenase inhibitors in antitubercular therapy led to bactericidal response, even in monotherapy. However, the absence of the cryo-EM structure of Mycobacterium tuberculosis type II NADH-dehydrogenase has constrained drug discovery efforts to rely on high-throughput screening methods, limiting the use of structure-based drug discovery. Here, we have delineated the literature-reported Mycobacterium tuberculosis type II NADH-dehydrogenase inhibitors and the rationale behind selecting this specific enzyme for antitubercular drug discovery, along with shedding light on the architecture of the enzyme structure and functionality. The gap in the current research and future research direction for TB treatment have been addressed.

The emergence of azole resistance and tolerance in pathogenic fungi has emerged as a significant public health concern, emphasizing the urgency for innovative strategies to bolster the efficacy of azole-based treatments. Drug repurposing stands as a promising and practical avenue for advancing antifungal therapy, with the potential for swift clinical translation. This review offers a comprehensive overview of azole synergistic agents uncovered through drug repurposing strategies, alongside an in-depth exploration of the mechanisms by which these agents augment azole potency. Drawing from these mechanisms, we delineate strategies aimed at enhancing azole effectiveness, such as inhibiting efflux pumps to elevate azole concentrations within fungal cells, intensifying ergosterol synthesis inhibition, mitigating fungal cell resistance to azoles, and disrupting biological processes extending beyond ergosterol synthesis. This review is beneficial for the development of these potentiators, as it meticulously examines instances and provides nuanced discussions on the mechanisms underlying the progression of azole potentiators through drug repurposing strategies.

Schistosomiasis is the infection caused by Schistosoma mansoni and constitutes a worldwide public health problem. The parasitological recommended method and serological methods can be used for the detection of eggs and antibodies, respectively. However, both have limitations, especially in low endemicity areas. Thus, new approaches for the diagnosis of schistosomiasis are essential. In this study, a six-amino acid peptide and derived sequences from SmATPDase1 were synthesized for the evaluation of immunogenicity. SmATPDase1 is included in a protein group in S. mansoni tegument; therefore, its peptides could be potential candidates for diagnostic antigens. In the hypothetical SmATPDase1 three-dimensional structure, peptides are located in a region exposed and accessible to antibody binding. In addition, peptide amino acid sequences are conserved in the most relevant Schistosoma species and have low identity with human NTPDases isoforms. Swiss mice immunization resulted in significant anti-peptide polyclonal antibodies production, which recognized a 63 kDa protein in tegument and adult worm preparations. By immunofluorescence microscopy, polyclonal antibodies also identified this enzyme in cercariae. Sera of infected animals presented high seropositivity in ELISA-peptides, with an area under curve (AUC) greater than 0.96 for all peptides. In mice with low parasite burden, we observed a seropositivity AUC > 0.9. Reactivity in the prepatent period exhibited AUC values greater than 0.94 for all peptides. Anti-P1425 monoclonal antibodies were successfully produced, and mAbs recognized the integral protein in ELISA and Western blots. The data indicate that peptides from SmATPDase1 are potential biomarkers for schistosomiasis, and anti-peptide antibodies are interesting tools for the detection of the infection.

Plants provide an abundant source of potential therapeutic agents, including a diverse array of compounds, such as cyclotides, which are peptides known for their antimicrobial activity. Cyclotides are multifaceted molecules with a wide range of biological activities. Their unique topology forms a head-to-tail cyclic structure reinforced by a cysteine knot, which confers chemical and thermal stability. These molecules can directly target membranes of infectious agents by binding to phosphatidylethanolamine in lipid membranes, leading to membrane permeabilization. Additionally, they function as carriers and cell-penetrating molecules, demonstrating antiviral, antibacterial, antifungal, and nematicidal properties. The structure of cyclotides is also amenable to chemical synthesis, facilitating drug design through residue substitutions or grafting of bioactive epitopes within the cyclotide scaffold to enhance peptide stability. In this review, we explore the multifunctionality of these biomolecules as anti-infective agents, emphasizing their potential as a novel class of antimicrobial drugs.

The complete tricarboxylic acid (TCA) cycle, comprising a series of 8 oxidative reactions, occurs in most eukaryotes in the mitochondria and in many prokaryotes. The net outcome of these 8 chemical reactions is the release of the reduced electron carriers NADH and FADH₂, water, and carbon dioxide. The parasites of the Plasmodium spp., belonging to the phylum Apicomplexa, have all the genes for a complete TCA cycle. The parasite completes its life cycle across two hosts, the insect vector mosquito and a range of vertebrate hosts including humans. As the niches that the parasite invades and occupies in the two hosts vary dramatically in their biochemical nature and availability of nutrients, the parasite's energy metabolism has been accordingly adapted to its host environment. One such pathway that shows extensive metabolic plasticity in parasites of the Plasmodium spp. is the TCA cycle. Recent studies using isotope-tracing targeted-metabolomics have highlighted conserved and parasite-specific features in the TCA cycle. This Review provides a comprehensive summary of what is known of this central pathway in the Plasmodium spp.

Developing new classes of drugs that are active against infections caused by Mycobacterium tuberculosis is a priority for treating and managing this deadly disease. Here, we describe screening a small library of 20 DNA gyrase inhibitors and identifying new lead compounds. Three structurally diverse analogues were identified with minimal inhibitory concentrations of 0.125 μg/mL against both drug-susceptible and drug-resistant strains of M. tuberculosis. These lead compounds also demonstrated antitubercular activity in ex vivo studies using infected THP-1 macrophages with minimal cytotoxicity in THP-1, HeLa, and HepG2 cells (IC₅₀ ≥ 128 μg/mL). The molecular target of the lead compounds was validated through biochemical studies of select analogues with purified M. tuberculosis gyrase and the generation of resistant mutants. The lead compounds were assessed in combination with bedaquiline and pretomanid to determine the clinical potential, and the select lead (158) demonstrated in vivo efficacy in an acute model of TB infection in mice, reducing the lung bacterial burden by approximately 3 log₁₀ versus untreated control mice. The advancement of DNA gyrase inhibitors expands the field of innovative therapies for tuberculosis and may offer an alternative to fluoroquinolones in future therapeutic regimens.