The rapid emergence and spread of multidrug-resistant bacterial pathogens require the development of antibacterial agents that are robustly effective while inducing no toxicity or resistance development. In this context, we designed and synthesized amphiphilic dendrimers as antibacterial candidates. We report the promising potent antibacterial activity shown by the amphiphilic dendrimer , composed of a long hydrophobic alkyl chain and a tertiary amine-terminated poly(amidoamine) dendron, against a panel of Gram-negative bacteria, including multidrug-resistant and exhibited effective activity against drug-resistant bacterial infections in vivo.
View Article and Find Full Text PDFUnlabelled: (pneumococcus) causes a wide range of important human infectious diseases, including pneumonia, pneumonia-derived sepsis, otitis media, and meningitis. Pneumococcus produces numerous secreted proteins that are critical for normal physiology and pathogenesis. The membrane targeting and translocation of these secreted proteins are partly mediated by the signal recognition particle (SRP) complex, which consists of 4.
View Article and Find Full Text PDFInfections caused by Gram-negative pathogens are increasingly prevalent and are typically treated with broad-spectrum antibiotics, resulting in disruption of the gut microbiome and susceptibility to secondary infections. There is a critical need for antibiotics that are selective both for Gram-negative bacteria over Gram-positive bacteria, as well as for pathogenic bacteria over commensal bacteria. Here we report the design and discovery of lolamicin, a Gram-negative-specific antibiotic targeting the lipoprotein transport system.
View Article and Find Full Text PDFCompetence development in (pneumococcus) is tightly intertwined with virulence. In addition to genes encoding genetic transformation machinery, the competence regulon also regulates the expression of allolytic factors, bacteriocins, and cytotoxins. Pneumococcal competence system has been extensively interrogated where the short transient competent state upregulates the expression of three distinct phases of "early," "late," and "delayed" genes.
View Article and Find Full Text PDFModern medicine continues to struggle against antibiotic-resistant bacterial pathogens. Among the pathogens of critical concerns are the multidrug-resistant (MDR) , and . These pathogens are major causes of nosocomial infections among immunocompromised individuals, involving major organs such as lung, skin, spleen, kidney, liver, and bloodstream.
View Article and Find Full Text PDFCell Mol Gastroenterol Hepatol
January 2024
Indiscriminate use of antibiotics has imposed a selective pressure for the rapid rise in bacterial resistance, creating an urgent need for novel therapeutics for managing bacterial infectious diseases while counteracting bacterial resistance. Carbapenem-resistant strains have become a major challenge in modern medicine due to their ability to cause an array of severe infections. Recently, we have shown that the 20-mer random peptide mixtures are effective therapeutics against three ESKAPEE pathogens.
View Article and Find Full Text PDFInhibition of overexpressed enzymes is among the most promising approaches for targeted cancer treatment. However, many cancer-expressed enzymes are "nonlethal," in that the inhibition of the enzymes' activity is insufficient to kill cancer cells. Conventional antibody-based therapeutics can mediate efficient treatment by targeting extracellular nonlethal targets but can hardly target intracellular enzymes.
View Article and Find Full Text PDFSubverting the host immune system is a major task for any given pathogen to assure its survival and proliferation. For the opportunistic human pathogen (Bc), immune evasion enables the establishment of potent infections. In various species of the Bc group, the pleiotropic regulator PlcR and its cognate cell-cell signaling peptide PapR regulate virulence gene expression in response to fluctuations in population density, i.
View Article and Find Full Text PDFThe prevalence of orthopedic implants is increasing with an aging population. These patients are vulnerable to risks from periprosthetic infections and instrument failures. Here, we present a dual-functional smart polymer foil coating compatible with commercial orthopedic implants to address both septic and aseptic failures.
View Article and Find Full Text PDFBackground And Aims: NASH, characterized by inflammation and fibrosis, is emerging as a leading etiology of HCC. Lipidomics analyses in the liver have shown that the levels of polyunsaturated phosphatidylcholine (PC) are decreased in patients with NASH, but the roles of membrane PC composition in the pathogenesis of NASH have not been investigated. Lysophosphatidylcholine acyltransferase 3 (LPCAT3), a phospholipid (PL) remodeling enzyme that produces polyunsaturated PLs, is a major determinant of membrane PC content in the liver.
View Article and Find Full Text PDFGenomic studies and experiments with permeability-deficient strains have revealed a variety of biological targets that can be engaged to kill Gram-negative bacteria. However, the formidable outer membrane and promiscuous efflux pumps of these pathogens prevent many candidate antibiotics from reaching these targets. One such promising target is the enzyme FabI, which catalyzes the rate-determining step in bacterial fatty acid biosynthesis.
View Article and Find Full Text PDFThe competence regulon of (pneumococcus) is a quorum-sensing circuitry that regulates the ability of this pathogen to acquire antibiotic resistance or perform serotype switching, leading to vaccine-escape serotypes, via horizontal gene transfer, as well as initiate virulence. Induction of the competence regulon is centered on binding of the competence-stimulating peptide (CSP) to its cognate receptor, ComD. We have recently synthesized multiple dominant-negative peptide analogs capable of inhibiting competence induction and virulence in .
View Article and Find Full Text PDF(pneumococcus) is a prevalent human pathogen that utilizes the competence regulon quorum sensing circuitry to acquire antibiotic resistance and initiate its attack on the human host. Therefore, targeting the competence regulon can be applied as an anti-infective approach with minimal pressure for resistance development. Herein, we report the construction of a library of urea-bridged cyclic dominant-negative competence-stimulating peptide (dnCSP) derivatives and their evaluation as competitive inhibitors of the competence regulon.
View Article and Find Full Text PDFAntibiotic resistance is one of the greatest crises in human medicine. Increased incidents of antibiotic resistance are linked to clinical overuse and overreliance on antibiotics. Among the ESKAPE pathogens, , especially carbapenem-resistant isolates, has emerged as a significant threat in the context of blood, urinary tract, lung, and wound infections.
View Article and Find Full Text PDFAntibiotic resistance is a daunting challenge in modern medicine, and novel approaches that minimize the emergence of resistant pathogens are desperately needed. Antimicrobial peptides are newer therapeutics that attempt to do this; however, they fall short because of low to moderate antimicrobial activity, low protease stability, susceptibility to resistance development, and high cost of production. The recently developed random peptide mixtures (RPMs) are promising alternatives.
View Article and Find Full Text PDFFusidic acid (FA) is a potent steroidal antibiotic that has been used in Europe for more than 60 years to treat a variety of infections caused by Gram-positive pathogens. Despite its clinical success, FA requires significantly elevated dosing (3 g on the first day, 1.2 g on subsequent days) to minimize resistance, as FA displays a high resistance frequency, and a large shift in minimum inhibitory concentration is observed for resistant bacteria.
View Article and Find Full Text PDFInfections by intracellular pathogens are difficult to treat because of the poor accessibility of antibiotics to the pathogens encased by host cell membranes. As such, a strategy that can improve the membrane permeability of antibiotics would significantly increase their efficiency against the intracellular pathogens. Here, we report the design of an adaptive, metaphilic cell-penetrating polypeptide (CPP)-antibiotic conjugate (VPP-G) that can effectively eradicate the intracellular bacteria both and .
View Article and Find Full Text PDFPulmonary mycoses are difficult to treat and detrimental to patients. Fungal infections modulate the lung immune response, induce goblet cell hyperplasia and metaplasia, and mucus hypersecretion in the airways. Excessive mucus clogs small airways and reduces pulmonary function by decreasing oxygen exchange, leading to respiratory distress.
View Article and Find Full Text PDFThe virulence behaviors of many Gram-negative bacterial pathogens are governed by quorum-sensing (QS), a hierarchical system of gene regulation that relies on population density by producing and detecting extracellular signaling molecules. Although extensively studied under conditions, adaptation of QS system to physiologically relevant host environment is not fully understood. In this study, we investigated the influence of lung environment on the regulation of virulence factors by QS in a mouse model of acute pneumonia.
View Article and Find Full Text PDFMultidrug-resistant Gram-negative (GN) infections for which there are few available treatment options are increasingly common. The development of new antibiotics for these pathogens is challenging because of the inability of most small molecules to accumulate inside GN bacteria. Using recently developed predictive guidelines for compound accumulation in , we have converted the antibiotic Ribocil C, which targets the flavin mononucleotide (FMN) riboswitch, from a compound lacking whole-cell activity against wild-type GN pathogens into a compound that accumulates to a high level in , is effective against Gram-negative clinical isolates, and has efficacy in mouse models of GN infections.
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