ACS Infectious Diseases最新文献

High-throughput screening (HTS) of small molecules is a starting point for many drug development pipelines, including tuberculosis. These screens often result in multiple hits whose mechanisms of action remain unknown. From our initial HTS of the Molecular Libraries Small Molecule Repository (MLSMR), we cherry-picked 935 compounds that inhibited the growth of Mycobacterium tuberculosis and set out to provide an early assessment of their antimycobacterial properties and mechanism of action. To characterize the MLSMR Mtb growth inhibitors, a combination of cheminformatics and targeted mutant screening against mutants in katG, hadAB, and a mixed pool of mmpL3 mutants was used to characterize the hits. As a validation of this approach, we identified 101 isoniazid analogs that predictably lose all their antimycobacterial activities against the katG mutant. Interestingly, eight isoniazid analogs retain part of their activity against the mutant, suggesting an alternative KatG-independent mechanism. This approach also identified new compounds belonging to already known scaffolds that target HadAB or MmpL3. Additionally, we explored the nitro-containing compounds in our data set and discovered nitrofuranyl benzothiazoles that show enhanced activity against the mmpL3 and katG mutants, a phenomenon known as collateral sensitivity. Overall, this study will serve as an important resource for further follow-up studies of antitubercular small molecules in the MLSMR library and provide a well-characterized training set for artificial intelligence-driven antimycobacterial drug discovery.

High-throughput screening (HTS) of small molecules is a starting point for many drug development pipelines, including tuberculosis. These screens often result in multiple hits whose mechanisms of action remain unknown. From our initial HTS of the Molecular Libraries Small Molecule Repository (MLSMR), we cherry-picked 935 compounds that inhibited the growth of Mycobacterium tuberculosis and set out to provide an early assessment of their antimycobacterial properties and mechanism of action. To characterize the MLSMR Mtb growth inhibitors, a combination of cheminformatics and targeted mutant screening against mutants in katG, hadAB, and a mixed pool of mmpL3 mutants was used to characterize the hits. As a validation of this approach, we identified 101 isoniazid analogs that predictably lose all their antimycobacterial activities against the katG mutant. Interestingly, eight isoniazid analogs retain part of their activity against the mutant, suggesting an alternative KatG-independent mechanism. This approach also identified new compounds belonging to already known scaffolds that target HadAB or MmpL3. Additionally, we explored the nitro-containing compounds in our data set and discovered nitrofuranyl benzothiazoles that show enhanced activity against the mmpL3 and katG mutants, a phenomenon known as collateral sensitivity. Overall, this study will serve as an important resource for further follow-up studies of antitubercular small molecules in the MLSMR library and provide a well-characterized training set for artificial intelligence-driven antimycobacterial drug discovery.

Vaccine adjuvants are critical to improve the immunogenicity, efficacy, and durability of vaccines; however, their development has lagged behind that of vaccine antigens. Monophosphoryl lipid A (MPLA), a clinically approved adjuvant that stimulates Toll-like receptor 4 (TLR4), faces manufacturing challenges due to its complex and long synthesis. With the aim of simplifying the structure of MPLA while retaining its biological activity, we developed monosaccharide-based molecules FP18 and FP20Rha that activate TLR4 signaling. Both TLR4 agonists induced robust antibody activity against the model antigen, ovalbumin. Here, we report the potential of these TLR4 agonists to enhance the protective efficacy of the well-characterized OprF antigen against P. aeruginosa infection. OprF adjuvanted with FP18 showed reduced bacterial loads in lungs and spleens, relative to antigen alone in an acute P. aeruginosa pneumonia model. FP18-adjuvanted OprF also enhanced the production of anti-OprF antibodies and stimulated IFNγ and TNF in CD4⁺ T cells, suggesting a Th1-skewed cellular immune response. These adjuvants have promise for accelerating the development of effective vaccines against P. aeruginosa and other infectious diseases.

Vaccine adjuvants are critical to improve the immunogenicity, efficacy, and durability of vaccines; however, their development has lagged behind that of vaccine antigens. Monophosphoryl lipid A (MPLA), a clinically approved adjuvant that stimulates Toll-like receptor 4 (TLR4), faces manufacturing challenges due to its complex and long synthesis. With the aim of simplifying the structure of MPLA while retaining its biological activity, we developed monosaccharide-based molecules FP18 and FP20Rha that activate TLR4 signaling. Both TLR4 agonists induced robust antibody activity against the model antigen, ovalbumin. Here, we report the potential of these TLR4 agonists to enhance the protective efficacy of the well-characterized OprF antigen against P. aeruginosa infection. OprF adjuvanted with FP18 showed reduced bacterial loads in lungs and spleens, relative to antigen alone in an acute P. aeruginosa pneumonia model. FP18-adjuvanted OprF also enhanced the production of anti-OprF antibodies and stimulated IFNγ and TNF in CD4⁺ T cells, suggesting a Th1-skewed cellular immune response. These adjuvants have promise for accelerating the development of effective vaccines against P. aeruginosa and other infectious diseases.

Among the critical priority pathogens listed by the World Health Organization, Mycobacterium tuberculosis strains resistant to rifampicin present a significant global threat. Consequently, the study of the mechanisms of resistance to new antitubercular drugs and the discovery of new effective molecules are two crucial points in tuberculosis drug discovery. In this study, we discovered a compound named RCB18350, which is active against M. tuberculosis growth and exhibits a minimum inhibitory concentration (MIC) of 1.25 μg/mL. It was also effective against multidrug-resistant isolates. We deeply studied the mechanism of resistance/action of RCB18350 by using several approaches. We found that Rv3406, an iron- and α-ketoglutarate-dependent sulfate ester dioxygenase, is capable of metabolizing the compound into its inactive metabolite. This finding highlights the role of this enzyme in the mechanism of resistance to RCB18350.

Among the critical priority pathogens listed by the World Health Organization, Mycobacterium tuberculosis strains resistant to rifampicin present a significant global threat. Consequently, the study of the mechanisms of resistance to new antitubercular drugs and the discovery of new effective molecules are two crucial points in tuberculosis drug discovery. In this study, we discovered a compound named RCB18350, which is active against M. tuberculosis growth and exhibits a minimum inhibitory concentration (MIC) of 1.25 μg/mL. It was also effective against multidrug-resistant isolates. We deeply studied the mechanism of resistance/action of RCB18350 by using several approaches. We found that Rv3406, an iron- and α-ketoglutarate-dependent sulfate ester dioxygenase, is capable of metabolizing the compound into its inactive metabolite. This finding highlights the role of this enzyme in the mechanism of resistance to RCB18350.

Pneumonia caused by Staphylococcus aureus infection has consistently been a significant cause of morbidity and mortality worldwide. Extensive research to date indicates that N6-methyladenosine (m6A) modification plays a crucial role in the development and progression of various diseases. However, it remains unknown whether the m6A modification affects the progression of bacterial pneumonia. To explore this question, we assessed the levels of m6A as well as the expression of methyltransferases (METTL3 and METTL14), demethylase fat mass and obesity-related protein (FTO), and methylation reader proteins YTHDF1 and YTHDF2 in mice and MH-S cells during S. aureus infection. The levels of m6A and METTL3 were significantly upregulated in S. aureus-infected mice and MH-S cells. siMETTL3 knockdown resulted in more severe bacterial colonization, lung damage, increased inflammatory cytokines (IL-6, IL-1β, TNF-α), and mortality rates in mice as well as MH-S cells following the bacterial infection. Regulation of lung inflammation levels by METTL3 was associated with the activation of the MAPK/NF-κB/JAK2-STAT3 signaling pathway. Moreover, siMETTL3 mice exhibited an increased release of superoxides and exacerbated oxidative stress in the lungs following S. aureus infection, which was correlated with impaired mitochondrial autophagy mediated by the Pink1/Parkin pathway. Our findings provide previously unrecognized evidence of the protective role of METTL3 in S. aureus-induced acute pneumonia, indicating a potential therapeutic target for S. aureus infections.

Pneumonia caused by Staphylococcus aureus infection has consistently been a significant cause of morbidity and mortality worldwide. Extensive research to date indicates that N6-methyladenosine (m6A) modification plays a crucial role in the development and progression of various diseases. However, it remains unknown whether the m6A modification affects the progression of bacterial pneumonia. To explore this question, we assessed the levels of m6A as well as the expression of methyltransferases (METTL3 and METTL14), demethylase fat mass and obesity-related protein (FTO), and methylation reader proteins YTHDF1 and YTHDF2 in mice and MH-S cells during S. aureus infection. The levels of m6A and METTL3 were significantly upregulated in S. aureus-infected mice and MH-S cells. siMETTL3 knockdown resulted in more severe bacterial colonization, lung damage, increased inflammatory cytokines (IL-6, IL-1β, TNF-α), and mortality rates in mice as well as MH-S cells following the bacterial infection. Regulation of lung inflammation levels by METTL3 was associated with the activation of the MAPK/NF-κB/JAK2-STAT3 signaling pathway. Moreover, siMETTL3 mice exhibited an increased release of superoxides and exacerbated oxidative stress in the lungs following S. aureus infection, which was correlated with impaired mitochondrial autophagy mediated by the Pink1/Parkin pathway. Our findings provide previously unrecognized evidence of the protective role of METTL3 in S. aureus-induced acute pneumonia, indicating a potential therapeutic target for S. aureus infections.

Tuberculosis remains a major global health threat, with traditional antibiotic treatments facing challenges such as drug resistance. Host-directed therapy (HDT) has emerged as a promising approach to combat tuberculosis by enhancing the host immune response. CXCL14, a chemokine family member, plays a crucial role in regulating host antipathogenic immune responses. To elucidate the role of CXCL14 and its key regulatory molecules in mycobacterial infections, we identified new targets for host-directed therapy. RAW264.7 macrophages were pretreated with CXCL14 and infected with Mycobacterium smegmatis. CFU, ROS levels, and apoptosis were assessed. Cell RNA was extracted for high-throughput sequencing, and significantly differentially expressed genes were screened and identified. The effects of candidate genes were verified using knockdown and overexpression techniques. A mouse model of mycobacterial infection was established to validate the role of CXCL14 in vivo. CXCL14 pretreatment significantly reduced intracellular mycobacteria and increased ROS levels in macrophages without affecting apoptosis. Transcriptome analysis identified A20 as a key differentially expressed gene. A20 overexpression promoted ROS production and decreased intracellular mycobacteria, while A20 knockdown reversed these effects. The combination of CXCL14 and A20 overexpression effectively inhibited mycobacterial survival in macrophages. CXCL14 significantly inhibited mycobacterial survival in mice and reduced organ damage in vivo. CXCL14 promoted ROS production in macrophages by upregulating A20 expression, thereby inhibiting mycobacterial survival. In the mouse model, CXCL14 alleviated inflammatory responses and histopathological damage caused by mycobacterial infection. These findings suggest that CXCL14 is a promising new HDT molecule for the treatment of mycobacterial infections.

Antimicrobial resistance (AMR) poses a major threat to human health globally. Approximately 5 million deaths were attributed to AMR in 2019, and this figure is predicted to worsen, reaching 10 million deaths by 2050. In the search for new compounds that can tackle AMR, FtsZ inhibitors represent a valuable option. In the present study, a structure-based virtual screening is reported, which led to the identification of derivative C11 endowed with an excellent minimum inhibitory concentration value of 2 μg/mL against Staphylococcus aureus. Biochemical assays clarified that compound C11 targets FtsZ by inhibiting its polymerization process. C11 also showed notable antimicrobial activity against S. aureus cystic fibrosis isolates and methicillin-resistant S. aureus strains. Derivative C11 did not show cytotoxicity, while it had a synergistic effect with methicillin. C11 also showed increased survival in the Galleria mellonella infection model. Lastly, structure–activity relationship and binding mode analyses were reported.