Screening of plant-based natural compounds as an inhibitor of FtsZ from Salmonella Typhi using the computational, biochemical and in vitro cell-based studies

Identification of potential inhibitors of tropomyosin receptor kinase B targeting CNS-related disorders and cancers

Tropomyosin receptor kinase B (TrkB), also known as neurotrophic tyrosine kinase receptor type 2 (NTRK2), is a protein that belongs to the family of receptor tyrosine kinases (RTKs). NTRK2 plays a crucial role in regulating the development and maturation of the central nervous system (CNS) and peripheral nervous system (PNS). Elevated TrkB expression levels observed in different pathological conditions make it a potential target for therapeutic interventions against neurological disorders, including depression, anxiety, Alzheimer's disease, Parkinson's disease, and certain types of cancer. Targeting TrkB using small molecule inhibitors is a promising strategy for the treatment of a variety of neurological disorders. In this research, a systematic virtual screening was carried out on phytoconstituents found in the IMPPAT library to identify compounds potentially inhibiting TrkB. The retrieved compounds from the IMPPAT library were first filtered using Lipinski's rule of five. The compounds were then sorted based on their docking score and ligand efficiency. In addition, PAINS, ADMET, and PASS evaluations were carried out for selecting drug-like compounds. Finally, in interaction analysis, we found two phytoconstituents, Wedelolactone and 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (DMCA), which possessed considerable docking scores and specificity on the TrkB ATP-binding pocket. The selected compounds were further assessed employing molecular dynamics (MD) simulations and essential dynamics. The results revealed that the elucidated compounds bind well with the TrkB binding pocket and lead to fewer conformations fluctuations. This study highlighted using phytoconstituents, Wedelolactone and DMCA as starting leads in developing novel TrkB inhibitors.Communicated by Ramaswamy H. Sarma.

Streptothricin-F Inhibition of FtsZ Function: A Promising Approach for Controlling Pseudomonas syringae pv. actinidiae

Pseudomonas syringae pv. actinidiae (Psa) is a significant pathogenic bacterium affecting the kiwifruit industry. This study investigated the target sites of streptothricin-F (ST-F), produced by Streptomyces lavendulae gCLA4. The inhibition of ST-F on Psa was examined by the microscopic structural differences of Psa before and after treatment with ST-F, as well as the interaction between ST-F and cell division-related proteins. The results revealed filamentation of Psa after ST-F treatment, and fluorescence microscopy showed that ST-F inhibited the formation of the Z-ring composed of FtsZ protein. In vitro experiments and molecular docking demonstrated that ST-F can bind to FtsZ with a binding energy of 0.4 μM and inhibit FtsZ's GTP-dependent polymerization reaction. In addition, ST-F does not exert inhibitory effects on cell division in Psa strains overexpressing ftsZ. In conclusion, FtsZ is one of the target sites for ST-F inhibition of Psa, highlighting its potential as a therapeutic target for controlling Psa-induced kiwifruit bacterial canker.

Targeting neuroblastoma by small-molecule inhibitors of human ALYREF protein: mechanistic insights using molecular dynamics simulations

Neuroblastoma is a tumour of the sympathetic nervous system mainly prevalent in children. Many strategies have been employed to target several drug-targetable proteins for the clinical management of neuroblastoma. However, the heterogeneous nature of neuroblastoma presents serious challenges in drug development for its treatment. Albeit numerous medications have been developed to target various signalling pathways in neuroblastoma, the redundant nature of the tumour pathways makes its suppression unsuccessful. Recently, the quest for neuroblastoma therapy resulted in the identification of human ALYREF, a nuclear protein that plays an essential role in tumour growth and progression. Therefore, this study used the structure-based drug discovery method to identify the putative inhibitors targeting ALYREF for the Neuroblastoma treatment. Herein, a library of 119 blood-brain barrier crossing small molecules from the ChEMBL database was downloaded and docked against the predicted binding pocket of the human ALYREF protein. Based on docking scores, the top four compounds were considered for intermolecular interactions and molecular dynamics simulation analysis, which revealed CHEMBL3752986 and CHEMBL3753744 with substantial affinity and stability with the ALYREF. These results were further supported by binding free energies and essential dynamics analysis of the respective complexes. Hence, this study advocates the sorted compounds targeting ALYREF for further in vitro and in vivo assessment to develop a drug against neuroblastoma.Communicated by Ramaswamy H. Sarma.

Unrealized targets in the discovery of antibiotics for Gram-negative bacterial infections

Advances in areas that include genomics, systems biology, protein structure determination and artificial intelligence provide new opportunities for target-based antibacterial drug discovery. The selection of a 'good' new target for direct-acting antibacterial compounds is the first decision, for which multiple criteria must be explored, integrated and re-evaluated as drug discovery programmes progress. Criteria include essentiality of the target for bacterial survival, its conservation across different strains of the same species, bacterial species and growth conditions (which determines the spectrum of activity of a potential antibiotic) and the level of homology with human genes (which influences the potential for selective inhibition). Additionally, a bacterial target should have the potential to bind to drug-like molecules, and its subcellular location will govern the need for inhibitors to penetrate one or two bacterial membranes, which is a key challenge in targeting Gram-negative bacteria. The risk of the emergence of target-based drug resistance for drugs with single targets also requires consideration. This Review describes promising but as-yet-unrealized targets for antibacterial drugs against Gram-negative bacteria and examples of cognate inhibitors, and highlights lessons learned from past drug discovery programmes.

Antioxidative and ROS-dependent apoptotic effects of Cuscuta reflexa Roxb. stem against human lung cancer: network pharmacology and in vitro experimental validation

Lung cancer remains a formidable global health challenge, necessitating the exploration of novel therapeutic approaches. This study investigates the potential of Cuscuta reflexa Roxb. stem extract as an anticancer agent against human lung cancer, focusing on its antioxidative and ROS-dependent apoptotic effects. Utilizing a combination of network pharmacology and in-vitro experimental validation, we delineate the multifaceted molecular mechanisms underlying the observed effects. The antioxidant potential of C. reflexa stem extract was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH•), 2,2-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS•+) and ferric reducing/antioxidant power (FRAP), hydroxyl free radical scavenging, reactive nitrogen oxide scavenging and super oxide anion radical scavenging assays. Furthermore, the antiproliferative and proapoptotic effect of C. reflexa stem extract was evaluated against A549 lung adenocarcinoma cell line using the consecrated sulforhodamine B (SBR) and Annexin V-PI assays. Additionally, the mitochondrial membrane potential (MMP) and the total reactive oxygen species (ROS) estimation assays were performed. As a result, network pharmacology analysis revealed a complex interaction network between the bioactive constituents of C. reflexa and key proteins implicated in lung cancer progression. The C. reflexa stem extract showed dose-dependent antioxidant activity against DPPH• (IC50 - 87.38 µg/mL), reactive nitrogen oxide (IC50 - 318.34 µg/mL), FRAP (IC50 - 359.96 µg/mL), hydroxy free radicals (IC50 - 526.12 µg/mL) than ABTS●+ (IC50 - 698.45 µg/mL) and super oxide anion (IC50 - 892.71 µg/mL) as well as cytotoxic activity against A549 cells (IC50 - 436.80 µg/mL). Observations of morphological features in treated cells have revealed hallmark of apoptosis properties. Furthermore, as a result of treatment with C. reflexa stem extract, ROS generation and mitochondrial depolarization were increased in A549 cells, suggesting that this treatment has significant apoptotic properties. . These findings highlight the potential utility of this natural extract as an innovative therapeutic strategy for lung cancer treatment. The integration of network pharmacology and experimental validation enhances our understanding of the underlying mechanisms and provide the way for further translational research.Communicated by Ramaswamy H. Sarma.

Myricetin 3-rhamnoside retards the proliferation of hormone-independent breast cancer cells by targeting hyaluronidase

Breast cancer is the second-leading cause of cancer-related death in women and the most often diagnosed malignancy. As the majority of chemotherapeutic medications are associated with recurrence, drug resistance, and side effects, scientists are shifting to beneficial agents for prevention and treatment, such as natural molecules. Myricetin 3-rhamnoside, a natural flavonol glycoside is known for diverse pharmacological activities but fewer reports describe the antiproliferative ability. The study aims to investigate the antiproliferative efficacy and target [hyaluronidase (HYAL) and ornithine decarboxylase (ODC), two poor breast cancer prognostic markers] modulatory potential of myricetin 3-rhamnoside on breast cancer cell lines using cytotoxicity assays and in silico docking, molecular dynamics analysis, cell-free and cell-based test methods. Myricetin 3-rhamnoside significantly retard the growth of MDA-MB-231 cells in SRB (IC50 88.64 ± 7.14 µM) and MTT (56.26 ± 8.50 µM) assay. It suppressed the transition of cells to the S-phase by inducing arrest in the G0/G1 phase with a fold change of 1.10. It shows robust binding interaction with ODC (-7.90 kcal/mol) and HYAL (-9.46 kcal/mol) and inhibits ODC (15.22 ± 2.61 µM) and HYAL (11.92 ± 2.89 µM) activity, but in a cell-based assay, the prominent response was observed against HYAL (21.46 ± 4.03 µM). Besides, it shows a 1.38 fold-down regulation of HYAL and forms a stable complex with HYAL. The binding pocket for myricetin 3-rhamnoside and the simulation pocket during the simulation are identical, indicating that myricetin 3-rhamnoside is actively blocking hyaluronidase. The computational prediction suggests it is a safe molecule. These observations imply that myricetin 3-rhamnoside could be used as a pharmacophore to design and synthesize a novel and safe agent for managing hormone-independent breast cancer.Communicated by Ramaswamy H. Sarma.

Identification of potential Escherichia coli DNA gyrase B inhibitors targeting antibacterial therapy: an integrated docking and molecular dynamics simulation study

The alarming rise in the rate of antibiotic resistance is a matter of significant concern. DNA gyrase B (GyrB), a critical bacterial enzyme involved in DNA replication, transcription, and recombination, has emerged as a promising target for antibacterial agents. Inhibition of GyrB disrupts bacterial DNA replication, leading to cell death, making it an attractive candidate for antibiotic development. Although several classes of antibiotics targeting GyrB are currently in clinical use, the emergence of antibiotic resistance necessitates the exploration of novel inhibitors. In this study, we aimed to identify potential Escherichia coli GyrB inhibitors from a database of phytoconstituents sourced from Indian medicinal plants. Utilizing virtual screening, we performed a rigorous search to identify compounds with the most promising inhibitory properties against GyrB. Two compounds, namely Zizogenin and Cucurbitacin S, were identified based on their favorable drug likeliness and pharmacokinetic profiles. Employing advanced computational techniques, we analyzed the binding interactions of Zizogenin and Cucurbitacin S with the ATP-binding site of GyrB through molecular docking simulations. Both compounds exhibited robust binding interactions, evidenced by their high docking energy scores. To assess the stability of these interactions, we conducted extensive 100 ns molecular dynamics (MD) simulations, which confirmed the stability of Zizogenin and Cucurbitacin S when bound to GyrB. In conclusion, our study highlights Zizogenin and Cucurbitacin S as promising candidates for potential antibacterial agents targeting GyrB. Experimental validation of these compounds is warranted to further explore their efficacy and potential as novel antibiotics to combat antibiotic-resistant bacteria.Communicated by Ramaswamy H. Sarma.

Identification of berberine as a potential therapeutic strategy for kidney clear cell carcinoma and COVID-19 based on analysis of large-scale datasets

Background

Regarding the global coronavirus disease 2019 (COVID)-19 pandemic, kidney clear cell carcinoma (KIRC) has acquired a higher infection probability and may induce fatal complications and death following COVID-19 infection. However, effective treatment strategies remain unavailable. Berberine exhibits significant antiviral and antitumour effects. Thus, this study aimed to provide a promising and reliable therapeutic strategy for clinical decision-making by exploring the therapeutic mechanism of berberine against KIRC/COVID-19.

Methods

Based on large-scale data analysis, the target genes, clinical risk, and immune and pharmacological mechanisms of berberine against KIRC/COVID-19 were systematically investigated.

Results

In total, 1,038 and 12,992 differentially expressed genes (DEGs) of COVID-19 and KIRC, respectively, were verified from Gene Expression Omnibus and The Cancer Genome Atlas databases, respectively, and 489 berberine target genes were obtained from official websites. After intersecting, 26 genes were considered potential berberine therapeutic targets for KIRC/COVID-19. Berberine mechanism of action against KIRC/COVID-19 was revealed by protein-protein interaction, gene ontology, and Kyoto Encyclopedia of Genes and Genomes with terms including protein interaction, cell proliferation, viral carcinogenesis, and the PI3K/Akt signalling pathway. In COVID-19 patients, ACOX1, LRRK2, MMP8, SLC1A3, CPT1A, H2AC11, H4C8, and SLC1A3 were closely related to disease severity, and the general survival of KIRC patients was closely related to ACOX1, APP, CPT1A, PLK1, and TYMS. Additionally, the risk signature accurately and sensitively depicted the overall survival and patient survival status for KIRC. Numerous neutrophils were enriched in the immune system of COVID-19 patients, and the lives of KIRC patients were endangered due to significant immune cell infiltration. Molecular docking studies indicated that berberine binds strongly to target proteins.

Conclusion

This study demonstrated berberine as a potential treatment option in pharmacological, immunological, and clinical practice. Moreover, its therapeutic effects may provide potential and reliable treatment options for patients with KIRC/COVID-19.

The Use of Star Anise-Cinnamon Essential Oil as an Alternative Antibiotic in Prevention of Salmonella Infections in Yellow Chickens

Salmonella is capable of harming human and animal health, and its multidrug resistance (MDR) has always been a public health problem. In addition, antibiotic-free or antibiotic-reduced policies have been implemented in poultry production. Therefore, the search for antibiotic alternatives is more urgent than ever before. The aim of this study was to assess the antibacterial activity of star anise-cinnamon essential oil (SCEO) in vitro and its prophylactic effect against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in vivo. The results demonstrated that SCEO is effective against Salmonella pullorum, Salmonella give, and Salmonella kentucky in vitro. Supplementation with SCEO could significantly decrease the infections of Salmonella pullorum and Salmonella give, whereas it could slightly but not significantly decrease the infection of Salmonella kentucky, while also significantly alleviating the body weight (BW) loss caused by the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens. The SCEO had the best prophylactic effect against the infection of Salmonella give in Yellow chickens, followed by the infection of Salmonella pullorum and the infection of Salmonella kentucky. The SCEO, used as an antibiotic alternative, could be an effective prevention strategy against the infections of Salmonella pullorum, Salmonella give, and Salmonella kentucky in Yellow chickens.