Fragment-Based De Novo Design Reveals a Small-Molecule Inhibitor ofHelicobacter PyloriHtrA

Molecular dynamics simulation-driven focused virtual screening and experimental validation of Fisetin as an inhibitor of Helicobacter pylori HtrA protease

Helicobacter pylori (H. pylori, Hp) is a primary contributor to various stomach diseases, including gastritis and gastric cancer. This bacterium can colonize gastric epithelial cells, compromising their integrity and leading to the development of these conditions. While antibiotics are the mainstay of treatment for H. pylori infections, their widespread use has led to serious issues with drug resistance. High-temperature requirement A (HtrA) protein is an active serine protease secreted by H. pylori, which can destroy gastric epithelium, thus helping H. pylori to colonize gastric mucosa efficiently. In this study, we identified three compounds-Quercetin, Fisetin, and Geniposide-as potential natural compounds that might specifically interact with the HtrA protein, based on molecular docking and molecular dynamics simulations (MDs). The casein hydrolysis experiment indicated that Fisetin could inhibit the activity of HtrA in hydrolyzing casein at the concentration of 50 μM m. Additionally, our in vitro antibacterial experiments further showed that Fisetin could effectively inhibit the growth of H. pylori in a concentration-dependent manner, with an inhibition rate of 80% achieved at a concentration of 10 μM. In summary, these results suggest that Fisetin has an inhibitory effect on the growth of H. pylori, and this study may be the first to reveal its obviously inhibitory effect on HtrA protein. Our findings imply that Fisetin could be a potential candidate for further research as a therapeutic agent targeting protein HtrA, providing a new direction for the exploration of lead compounds and potential drugs against H. pylori infections.

A comprehensive review on human disease-causing bacterial proteases and their impeding agents

Proteases are enzymes that catalyze the amide bond dissociation in polypeptide and protein peptide units. They are categorized into seven families and are responsible for a wide spectrum of human ailments, such as various types of cancers, skin infections, urinary tract infections etc. Specifically, the bacterial proteases cause a huge impact in the disease progression. Extracellular bacterial proteases break down the host defense proteins, while intracellular proteases are essential for pathogens virulence. Due to its involvement in disease pathogenesis and virulence, bacterial proteases are considered to be potential drug targets. Several studies have reported potential bacterial protease inhibitors in both Gram-positive and Gram-negative disease causing pathogens. In this study, we have comprehensively reviewed about the various human disease-causing cysteine, metallo, and serine bacterial proteases as well as their potential inhibitors.

Molecular Targets in Campylobacter Infections

Human campylobacteriosis results from foodborne infections with Campylobacter bacteria such as Campylobacter jejuni and Campylobacter coli, and represents a leading cause of bacterial gastroenteritis worldwide. After consumption of contaminated poultry meat, constituting the major source of pathogenic transfer to humans, infected patients develop abdominal pain and diarrhea. Post-infectious disorders following acute enteritis may occur and affect the nervous system, the joints or the intestines. Immunocompromising comorbidities in infected patients favor bacteremia, leading to vascular inflammation and septicemia. Prevention of human infection is achieved by hygiene measures focusing on the reduction of pathogenic food contamination. Molecular targets for the treatment and prevention of campylobacteriosis include bacterial pathogenicity and virulence factors involved in motility, adhesion, invasion, oxygen detoxification, acid resistance and biofilm formation. This repertoire of intervention measures has recently been completed by drugs dampening the pro-inflammatory immune responses induced by the Campylobacter endotoxin lipo-oligosaccharide. Novel pharmaceutical strategies will combine anti-pathogenic and anti-inflammatory effects to reduce the risk of both anti-microbial resistance and post-infectious sequelae of acute enteritis. Novel strategies and actual trends in the combat of Campylobacter infections are presented in this review, alongside molecular targets applied for prevention and treatment strategies.

Function, molecular mechanisms, and therapeutic potential of bacterial HtrA proteins: An evolving view

Members of the high temperature requirement A (HtrA) protein family are widely distributed amongst prokaryotic and eukaryotic species. HtrA proteins have ATP-independent dual chaperone-protease activity and mediate protein quality control. Emerging evidence indicates that HtrA family members are vital for establishing infections and bacterial survival under stress conditions. Bacterial HtrA proteins are increasingly thought of as important new targets for antibacterial drug development. Recent literature suggests that HtrA protein AlgW from Pseudomonas aeruginosa has distinct structural, functional, and regulatory characteristics. The novel dual-signal activation mechanism seen in AlgW is required to modulate stress and drug responses in bacteria, prompting us to review our understanding of the many HtrA proteins found in microorganisms. Here, we describe the distribution of HtrA gene orthologues in pathogenic bacteria, discuss their structure–function relationships, outline the molecular mechanisms exhibited by different bacterial HtrA proteins in bacteria under selective pressure, and review the significance of recently developed small molecule inhibitors targeting HtrA in pathogenic bacteria.

Emerging therapeutic targets for gastric cancer from a host-Helicobacter pylori interaction perspective

INTRODUCTION

Gastric cancer (GC) has the higher genetic, cytologic, and architectural heterogeneity compared to other gastrointestinal cancers. By inducing gastric inflammation, Helicobacter pylori (HP) may lead to GC through combining bacterial factors with host factors. In this regard, identification of the major therapeutic targets against the host-HP interactions plays a critical role in GC prevention, diagnosis, and treatment.

AREAS COVERED

This study offers new insights into the promising therapeutic targets against the angiogenesis, invasion, or metastasis of GC from a host-HP interaction perspective. To this end, MEDLINE, EMBASE, LILACS, AIM, and IndMed databases were searched for relevant articles since 1992.

EXPERT OPINION

Wnt signaling and COX pathway have a well-documented history in the genesis of GC by HP and might be considered as the most promising targets for early GC treatment. Destroying HP may decrease the risk of GC, but it cannot fully hinder the GC development induced by HP infection. Therefore, targeting HP-activated pathways, especially COX-2/Wnt/beta-catenin/VEGF, TLR2/TLR9/COX-2, COX2-PGE2, and NF-κB/COX-2, as well as EPHA2, MMPs, and miR-543/SIRT1 axis, can be an effective measure in the early treatment of GC. However, different clinical trials and large, multi-center cohorts are required to validate these potentially effective targets for GC therapy.

Automated De Novo Drug Design: Are We Nearly There Yet?

Medicinal chemistry and, in particular, drug design have often been perceived as more of an art than a science. The many unknowns of human disease and the sheer complexity of chemical space render decision making in medicinal chemistry exceptionally demanding. Computational models can assist the medicinal chemist in this endeavour. Provided here is an overview of recent examples of automated de novo molecular design, a discussion of the concepts and computational approaches involved, and the daring prediction of some of the possibilities and limitations of drug design using machine intelligence.