Discovery and Optimization of Novel SaFabI Inhibitors as Specific Therapeutic Agents for MRSA Infection.

As the rate-limiting enzyme in fatty acid biosynthesis, Staphylococcus aureus enoyl-acyl carrier protein reductase (SaFabI) emerges as a compelling target for combating methicillin-resistant S. aureus (MRSA) infections. Herein, compound 1, featuring a 4-(1H-benzo[d]imidazol-2-yl)pyrrolidin-2-one scaffold, was identified as a potent SaFabI inhibitor (IC50 = 976.8 nM) from an in-house library. Subsequent optimization yielded compound n31, with improved inhibitory efficacy on enzymatic activity (IC50 = 174.2 nM) and selective potency against S. aureus (MIC = 1-2 µg/mL). Mechanistically, n31 directly inhibited SaFabI in cellular contexts. Moreover, n31 exhibited favorable safety and pharmacokinetic profiles, and dose-dependently treated MRSA-induced skin infections, outperforming the approved drug, linezolid. The chiral separation of n31 resulted in (S)-n31, with superior activities (IC50 = 94.0 nM, MIC = 0.25-1 µg/mL) and in vivo therapeutic efficacy. In brief, our research proposes (S)-n31 as a promising candidate for SaFabI-targeted therapy, offering specific anti-S. aureus efficacy and potential for further development.

In vitro and in vivo enhancement effect of glabridin on the antibacterial activity of colistin, against multidrug resistant Escherichia coli strains.

BACKGROUND: The increase in antimicrobial resistance leads to complications in treatments, prolonged hospitalization, and increased mortality. Glabridin (GLA) is a hydroxyisoflavan from Glycyrrhiza glabra L. that exhibits multiple pharmacological activities. Colistin (COL), a last-resort antibiotic, is increasingly being used in clinic against Gram-negative bacteria. Previous reports have shown that GLA is able to sensitize first line antibiotics such as norfloxacin and vancomycin on Staphylococcus aureus, implying that the use of GLA as an antibiotic adjuvant is a promising strategy for addressing the issue of drug resistance. However, the adjuvant effect on other antibiotics, especially COL, on Gram-negative bacteria such as Escherichia coli has not been studied. PURPOSE: The objective of our study was to investigate the targets of GLA and the synergistic effect of GLA and COL in E. coli, and to provide further evidence for the use of GLA as an antibiotic adjuvant to alleviate the problem of drug resistance. METHODS: We first investigated the interaction between GLA and enoyl-acyl carrier protein reductase, also called "FabI", through enzyme inhibition assay, differential scanning fluorimetry, isothermal titration calorimetry and molecular docking assay. We tested the transmembrane capacity of GLA on its own and combined it with several antibiotics. The antimicrobial activities of GLA and COL were evaluated against six different susceptible and resistant E. coli in vitro. Their interactions were analyzed using checkerboard assay, time-kill curve and CompuSyn software. A series of sensitivity tests was conducted in E. coli overexpressing the fabI gene. The development of COL resistance in the presence of GLA was tested. The antimicrobial efficacy of GLA and COL in a mouse model of urinary tract infection was assessed. The anti-biofilm effects of GLA and COL were investigated. RESULTS: In this study, enzyme kinetic analysis and thermal analysis provided evidence for the interaction between GLA and FabI in E. coli. GLA enhanced the antimicrobial effect of COL and synergistically suppressed six different susceptible and resistant E. coli with COL. Overexpression experiments showed that targeted inhibition of FabI was a key mechanism by which GLA synergistically enhanced COL activity. The combination of GLA and COL slowed the development of COL resistance in E. coli. Combined GLA and COL treatment significantly reduced bacterial load and mitigated urinary tract injury in a mouse model of E. coli urinary tract infection. Additionally, GLA + COL inhibited the formation and eradication of biofilms and the synthesis of curli. CONCLUSION: Our findings indicate that GLA synergistically enhances antimicrobial activities of COL by targeting inhibition of FabI in E. coli. GLA is expected to continue to be developed as an antibiotic adjuvant to address drug resistance issues.

Mycobacterium tuberculosis: Pathogenesis and therapeutic targets.

Tuberculosis (TB) remains a significant public health concern in the 21st century, especially due to drug resistance, coinfection with diseases like immunodeficiency syndrome (AIDS) and coronavirus disease 2019, and the lengthy and costly treatment protocols. In this review, we summarize the pathogenesis of TB infection, therapeutic targets, and corresponding modulators, including first-line medications, current clinical trial drugs and molecules in preclinical assessment. Understanding the mechanisms of Mycobacterium tuberculosis (Mtb) infection and important biological targets can lead to innovative treatments. While most antitubercular agents target pathogen-related processes, host-directed therapy (HDT) modalities addressing immune defense, survival mechanisms, and immunopathology also hold promise. Mtb's adaptation to the human host involves manipulating host cellular mechanisms, and HDT aims to disrupt this manipulation to enhance treatment effectiveness. Our review provides valuable insights for future anti-TB drug development efforts.

Targeting caseinolytic protease P and its AAA1 chaperone for tuberculosis treatment.

Caseinolytic protease P with its AAA1 chaperone, known as Mycobacterium tuberculosis (Mtb)ClpP1P2 proteolytic machinery, maintains protein homeostasis in Mtb cells and is essential for bacterial survival. It is regarded as an important biological target with the potential to address the increasingly serious issue of multidrug-resistant (MDR) TB. Over the past 10 years, many MtbClpP1P2-targeted modulators have been identified and characterized, some of which have shown potent anti-TB activity. In this review, we describe current understanding of the substrates, structure and function of MtbClpP1P2, classify the modulators of this important protein machine into several categories based on their binding subunits or pockets, and discuss their binding details; Such information provides insights for use in candidate drug research and development of TB treatments by targeting MtbClpP1P2 proteolytic machinery.

Screening for obstructive sleep apnoea in patients with serious mental illness.

OBJECTIVE: Patients with serious mental illness (SMI) are at increased risk of obstructive sleep apnoea (OSA). Despite this, OSA is frequently under-recognised in the psychiatric population. This study describes the results of OSA screening in SMI patients. METHOD: Patients with SMI attending a metropolitan mental health clinic were screened for OSA using the OSA50, STOP-BANG Questionnaire (SBQ), Epworth Sleep Score (ESS) and the Pittsburgh Sleep Quality Index (PSQI). They were then offered diagnostic sleep testing via ResMed ApneaLinkTM and polysomnography. RESULTS: Of the 65 patients recruited, 65% had a primary diagnosis of schizophrenia or schizoaffective disorder, 85% were on antipsychotic medications and the majority were obese. Approximately 50% of patients reported poor sleep quality via the PSQI, in contrast to 12% with elevated daytime sleepiness via the ESS. 46% of our cohort were at risk of OSA due to an elevated OSA50 or SBQ. Of the five patients who agreed to proceed to diagnostic sleep testing, three were diagnosed with OSA. CONCLUSION: A high proportion of patients with psychiatric illness are at risk of sleep-disordered breathing. Sleep dissatisfaction is high. The low uptake of sleep investigation requires improved patient engagement to improve OSA diagnosis in this high-risk group.

Ribosome-targeting antibacterial agents: Advances, challenges, and opportunities.

Ribosomes, which synthesize proteins, are critical organelles for the survival and growth of bacteria. About 60% of approved antibiotics discovered so far combat pathogenic bacteria by targeting ribosomes. However, several issues, such as drug resistance and toxicity, have impeded the clinical use of ribosome-targeting antibiotics. Moreover, the complexity of the bacteria ribosome structure has retarded the discovery of new ribosome-targeting agents that are considered as the key to the drug-resistance and toxicity. To deal with these challenges, efforts such as medicinal chemistry optimization, combination treatment, and new drug delivery system have been developed. But not enough, the development of structural biology and new screening methods bring powerful tools, such as cryo-electron microscopy technology, advanced computer-aided drug design, and cell-free in vitro transcription/translation systems, for the discovery of novel ribosome-targeting antibiotics. Thus, in this paper, we overview the research on different aspects of bacterial ribosomes, especially focus on discussing the challenges in the discovery of ribosome-targeting antibacterial drugs and advances made to address issues such as drug-resistance and selectivity, which, we believe, provide perspectives for the discovery of novel antibiotics.

Tonsillectomy versus tonsillotomy for obstructive sleep-disordered breathing in children.

BACKGROUND: Obstructive sleep-disordered breathing (oSDB) is a condition encompassing breathing problems when asleep due to upper airway obstruction. In children, hypertrophy of the tonsils and/or adenoids is thought to be the commonest cause. As such, (adeno)tonsillectomy has long been the treatment of choice. A rise in partial removal of the tonsils over the last decade is due to the hypothesis that tonsillotomy is associated with lower postoperative morbidity and fewer complications. OBJECTIVES: To assess whether partial removal of the tonsils (intracapsular tonsillotomy) is as effective as total removal of the tonsils (extracapsular tonsillectomy) in relieving signs and symptoms of oSDB in children, and has lower postoperative morbidity and fewer complications. SEARCH METHODS: We searched the Cochrane ENT Trials Register; Central Register of Controlled Trials (CENTRAL); MEDLINE; EMBASE; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The search date was 22 July 2019. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing the effectiveness of (adeno)tonsillectomy with (adeno)tonsillotomy in children aged 2 to 16 years with oSDB. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods and assessed the certainty of the evidence for our pre-defined outcomes using GRADE. Our primary outcomes were disease-specific quality of life, peri-operative blood loss and the proportion of children requiring postoperative medical intervention (with or without hospitalisation). Secondary outcomes included postoperative pain, return to normal activity, recurrence of oSDB symptoms as a result of tonsil regrowth and reoperation rates. MAIN RESULTS: We included 22 studies (1984 children), with predominantly unclear or high risk of bias. Three studies used polysomnography as part of their inclusion criteria. Follow-up duration ranged from six days to six years. Although 19 studies reported on some of our outcomes, we could only pool the results from a few due both to the variety of outcomes and the measurement instruments used, and an absence of combinable data. Disease-specific quality of life Four studies (540 children; 484 (90%) analysed) reported this outcome; data could not be pooled due to the different outcome measurement instruments used. It is very uncertain whether there is any difference in disease-specific quality of life between the two surgical procedures in the short (0 to 6 months; 3 studies, 410 children), medium (7 to 13 months; 2 studies, 117 children) and long term (13 to 24 months; 1 study, 67 children) (very low-certainty evidence). Peri-operative blood loss We are uncertain whether tonsillotomy reduces peri-operative blood loss by a clinically meaningful amount (mean difference (MD) 14.06 mL, 95% CI 1.91 to 26.21 mL; 8 studies, 610 children; very low-certainty evidence). In sensitivity analysis (restricted to three studies with low risk of bias) there was no evidence of a difference between the groups. Postoperative complications requiring medical intervention (with or without hospitalisation) The risk of postoperative complications in the first week after surgery was probably lower in children who underwent tonsillotomy (4.9% versus 2.6%, risk ratio (RR) 1.75, 95% CI 1.06 to 2.91; 16 studies, 1416 children; moderate-certainty evidence). Postoperative pain Eleven studies (1017 children) reported this outcome. Pain was measured using various scales and scored by either children, parents, clinicians or study personnel. When considering postoperative pain there was little or no difference between tonsillectomy and tonsillotomy at 24 hours (10-point scale) (MD 1.09, 95% CI 0.88 to 1.29; 4 studies, 368 children); at two to three days (MD 0.93, 95% CI -0.14 to 2.00; 3 studies, 301 children); or at four to seven days (MD 1.07, 95% CI -0.40 to 2.53; 4 studies, 370 children) (all very low-certainty evidence). In sensitivity analysis (restricted to studies with low risk of bias), we found no evidence of a difference in mean pain scores between groups. Return to normal activity Tonsillotomy probably results in a faster return to normal activity. Children who underwent tonsillotomy were able to return to normal activity four days earlier (MD 3.84 days, 95% CI 0.23 to 7.44; 3 studies, 248 children; moderate-certainty evidence). Recurrence of oSDB and reoperation rates We are uncertain whether there is a difference between the groups in the short (RR 0.26, 95% CI 0.03 to 2.22; 3 studies, 186 children), medium (RR 0.35, 95% CI 0.04 to 3.23; 4 studies, 206 children) or long term (RR 0.21 95% CI 0.01 to 4.13; 1 study, 65 children) (all very low-certainty evidence). AUTHORS' CONCLUSIONS: For children with oSDB selected for tonsil surgery, tonsillotomy probably results in a faster return to normal activity (four days) and in a slight reduction in postoperative complications requiring medical intervention in the first week after surgery. This should be balanced against the clinical effectiveness of one operation over the other. However, this is not possible to determine in this review as data on the long-term effects of the two operations on oSDB symptoms, quality of life, oSDB recurrence and need for reoperation are limited and the evidence is of very low quality leading to a high degree of uncertainty about the results. More robust data from high-quality cohort studies, which may be more appropriate for detecting differences in less common events in the long term, are required to inform guidance on which tonsil surgery technique is best for children with oSDB requiring surgery.

Tonsillectomy or tonsillotomy? A systematic review for paediatric sleep-disordered breathing.

BACKGROUND: Recent evidence has challenged the practice of tonsillectomy in children with sleep-disordered breathing. Tonsillotomy (subtotal/partial/intracapsular tonsillectomy) has been proposed as an alternative with equivalent effectiveness and decreased post-operative morbidity, thus improving cost-effectiveness. OBJECTIVE: To systematically review the literature comparing clinical efficacy, post-operative morbidity, and cost-effectiveness of tonsillotomy and tonsillectomy in paediatric (<16yo) patients with sleep-disordered breathing. DATA SOURCES: A systematic search of MEDLINE, EMBASE, and CENTRAL (1984-July 2014) was conducted. Papers in English directly comparing post-operative outcomes in tonsillectomy and tonsillotomy in children undergoing surgery for sleep-disordered breathing were included. REVIEW METHODS: Two authors independently assessed abstracts for relevance, with disagreements resolved by a third author. Selected studies were independently assessed regarding inclusion and exclusion criteria. RESULTS: Thirty-two studies satisfied inclusion and exclusion criteria (19 randomised, 13 non-randomised). Patient satisfaction, quality-of-life, and polysomnographic improvement post-surgery did not vary between tonsillotomy and tonsillectomy. Tonsillotomy reduced the odds of a secondary haemorrhage by 79% (OR 0.21, 95% CI 0.17-0.27, p < 0.01), decreased post-operative pain and reduced return to normal oral intake by 2.8 days (95% CI 1.08-4.52, p < 0.01). The odds of readmission were decreased by 62% (OR 0.38, 95% CI 0.23-0.60, p < 0.01). Tonsillotomy had a slightly higher rate of symptom recurrence (4.51%) than tonsillectomy (2.55%), the long-term impact of which was unclear. CONCLUSION: Current evidence supports tonsillotomy in children with obstructive surgical indications. It is likely to reduce post-operative haemorrhage, pain, and facilitate a faster return to normal diet and activity. Healthcare burden is decreased due to fewer post-operative complications and reduced need for medical re-contact. More research is necessary to assess the risk of recurrence, and further classification of secondary haemorrhage severity is required to fully clarify the clinical benefit of tonsillotomy.

Phenylboronic acid modified silver nanoparticles for colorimetric dynamic analysis of glucose.

The development of advanced nanostructures that allow dynamic quantification of glucose level can contribute to tight glucose control in diabetes management and other medical/biological fields. In this paper, we demonstrated that the assemblies of the 5-amino-2-fluorophenylboronic acid modified silver nanoparticles (FPBA-AgNPs) can be employed for highly modulating, sensitive, and selective colorimetric sensing of glucose over a physiologically important concentration range of 0-20mM at a physiological pH of 7.4. The glucose-modulated assembly of the FPBA-AgNPs occurred by the regulable formation of interparticle linkages via the bridged binding of 1,2-cis-diols and 5,6-cis-diols (for furanose form; or 4,6-cis-diols for pyranose form), respectively, of a glucose molecule to two FPBA-AgNPs. The detection limit was 89.0 µM. The mean error of glucose detection in a macro-bio-system, blood serum of adult, was smaller than 10%. Furthermore, we show that the glucose level variations associated with a model biological reaction process can be monitored by using the FPBA-AgNPs, whilst with the reaction mechanism remaining nearly unchanged.

One-pot aqueous synthesis of sub-10 nm responsive nanogels.

A strategy involving free radical copolymerization of a difunctional oligomer and a small-molecule crosslinker to give sub-10 nm nanogels is proposed. These nanogels can adapt to surrounding temperatures and regulate the release of a preloaded model anticancer drug 5-fluorouracil.

Construction of near-infrared photonic crystal glucose-sensing materials for ratiometric sensing of glucose in tears.

Noninvasive monitoring of glucose in tears is highly desirable in tight glucose control. The polymerized crystalline colloidal array (PCCA) that can be incorporated into contact lens represents one of the most promising materials for noninvasive monitoring of glucose in tears. However, low sensitivity and slow time response of the PCCA reported in previous arts has limited its clinical utility. This paper presents a new PCCA, denoted as NIR-PCCA, comprising a CCA of glucose-responsive sub-micrometered poly(styrene-co-acrylamide-co-3-acrylamidophenylboronic acid) microgels embedded within a slightly positive charged hydrogel matrix of poly(acrylamide-co-2-(dimethylamino)ethyl acrylate). This newly designed NIR-PCCA can reflect near-infrared (NIR) light, whose intensity (at 1722 nm) would decrease evidently with increasing glucose concentration over the physiologically relevant range in tears. The lowest glucose concentration reliably detectable was as low as ca. 6.1 µg/dL. The characteristic response time τ(sensing) was 22.1±0.2s when adding glucose to 7.5 mg/dL, and the higher the glucose concentration is, the faster the time response. Such a rationally designed NIR-PCCA is well suited for ratiometric NIR sensing of tear glucose under physiological conditions, thereby likely to bring this promising glucose-sensing material to the forefront of analytical devices for diabetes.

One-pot synthesis of responsive catalytic Au@PVP hybrid nanogels.

Responsive catalytic hybrid nanogels with Au nanoparticle cores and a polyvinylpyrrolidone (PVP) based gel shell are prepared through a novel one-pot approach. The embedded Au nanoparticles demonstrate both a pH-modulated catalytic activity and anti-aggregation properties upon recycling.