Analysing the essential proteins set of Plasmodium falciparum PF3D7 for novel drug targets identification against malaria.

BACKGROUND: Plasmodium falciparum is an obligate intracellular parasite of humans that causes malaria. Falciparum malaria is a major public health threat to human life responsible for high mortality. Currently, the risk of multi-drug resistance of P. falciparum is rapidly increasing. There is a need to address new anti-malarial therapeutics strategies to combat the drug-resistance threat. METHODS: The P. falciparum essential proteins were retrieved from the recently published studies. These proteins were initially scanned against human host and its gut microbiome proteome sets by comparative proteomics analyses. The human host non-homologs essential proteins of P. falciparum were additionally analysed for druggability potential via in silico methods to possibly identify novel therapeutic targets. Finally, the PfAp4AH target was prioritized for pharmacophore modelling based virtual screening and molecular docking analyses to identify potent inhibitors from drug-like compounds databases. RESULTS: The analyses identified six P. falciparum essential and human host non-homolog proteins that follow the key druggability features. These druggable targets have not been catalogued so far in the Drugbank repository. These prioritized proteins seem novel and promising drug targets against P. falciparum due to their key protein-protein interactions features in pathogen-specific biological pathways and to hold appropriate drug-like molecule binding pockets. The pharmacophore features based virtual screening of Pharmit resource predicted a lead compound i.e. MolPort-045-917-542 as a promising inhibitor of PfAp4AH among prioritized targets. CONCLUSION: The prioritized protein targets may worthy to test in malarial drug discovery programme to overcome the anti-malarial resistance issues. The in-vitro and in-vivo studies might be promising for additional validation of these prioritized lists of drug targets against malaria.

Potential druggable proteins and chimeric vaccine construct prioritization against Brucella melitensis from species core genome data.

The Brucella melitensis chronic infection and drug resistance emerged as a severe health problem in humans and domestic cattle. The pathogens fast genome sequences availability fetched the possibility to address novel therapeutics targets in a rationale way. We acquired the core genes set from 56 B. melitensis publically available complete genome sequences. A stringent bioinformatics layout of comparative genomics and reverse vaccinology was followed to identify potential druggable proteins and multi-epitope vaccine constructs from core genes. The 23 proteins were shortlisted as novel druggable targets based on their role in pathogen-specific metabolic pathways, non-homologous to human and human gut microbiome proteins and their druggability potential. Furthermore, potential chimeric vaccine constructs were generated from lead T and B-cell overlapped epitopes in combination with immune enhancer adjuvants and linkers sequences. The molecular docking and MD simulation analyses ensured stable molecular interaction of a finally prioritized vaccine construct with human immune cells receptors.

Population genetic structure of domain I of apical membrane antigen-1 in Plasmodium falciparum isolates from Hazara division of Pakistan.

BACKGROUND: The Plasmodium falciparum apical membrane antigen-1 (PfAMA1) is considered as an ideal vaccine candidate for malaria control due to its high level of immunogenicity and essential role in parasite survival. Among the three domains of PfAMA1 protein, hyper-variable region (HVR) of domain I is the most immunogenic. The present study was conducted to evaluate the extent of genetic diversity across HVR domain I of the pfama1 gene in P. falciparum isolates from Hazara division of Pakistan. METHODS: The HVR domain I of the pfama1 was amplified and sequenced from 20 P. falciparum positive cases from Hazara division of Pakistan. The sequences were analysed in context of global population data of P. falciparum from nine malaria endemic countries. The DNA sequence reads quality assessment, reads assembling, sequences alignment/phylogenetic and population genetic analyses were performed using Staden, Lasergene v. 7.1, MEGA7 and DnaSP v.5 software packages respectively. RESULTS: Total 14 mutations were found in Pakistani isolates with 12 parsimony informative sites. During comparison with global isolates, a novel non-synonymous mutation (Y240F) was found specifically in a single Pakistani sample with 5% frequency. The less number of mutations, haplotypes, recombination and low pairwise nucleotide differences revealed tightly linked uniform genetic structure with low genetic diversity at HVR domain I of pfama1 among P. falciparum isolates from Hazara region of Pakistan. This uniform genetic structure may be shaped across Pakistani P. falciparum isolates by bottleneck or natural selection events. CONCLUSION: The Pakistani P. falciparum isolates were found to maintain a distinct genetic pattern at HVR pfama1 with some extent of genetic relationship with geographically close Myanmar and Indian samples. However, the exact pattern of gene flow and demographic events may infer from whole genome sequence data with large sample size of P. falciparum collected from broad area of Pakistan.

Core-genome-mediated promising alternative drug and multi-epitope vaccine targets prioritization against infectious Clostridium difficile.

Prevention of Clostridium difficile infection is challenging worldwide owing to its high morbidity and mortality rates. C. difficile is currently being classified as an urgent threat by the CDC. Devising a new therapeutic strategy become indispensable against C. difficile infection due to its high rates of reinfection and increasing antimicrobial resistance. The current study is based on core proteome data of C. difficile to identify promising vaccine and drug candidates. Immunoinformatics and vaccinomics approaches were employed to construct multi-epitope-based chimeric vaccine constructs from top-ranked T- and B-cell epitopes. The efficacy of the designed vaccine was assessed by immunological analysis, immune receptor binding potential and immune simulation analyses. Additionally, subtractive proteomics and druggability analyses prioritized several promising and alternative drug targets against C. difficile. These include FMN-dependent nitroreductase which was prioritized for pharmacophore-based virtual screening of druggable molecule databases to predict potent inhibitors. A MolPort-001-785-965 druggable molecule was found to exhibit significant binding affinity with the conserved residues of FMN-dependent nitroreductase. The experimental validation of the therapeutic targets prioritized in the current study may worthy to identify new strategies to combat the drug-resistant C. difficile infection.

Chlamydia trachomatis core genome data mining for promising novel drug targets and chimeric vaccine candidates identification.

Chlamydia trachomatis is involved in most sexually transmitted diseases. The species has emerged as a major public health threat due to its multidrug-resistant capabilities, and new therapeutic target inferences have become indispensable to combat its pathogenesis. However, no commercial vaccine is yet available to treat the C. trachomatis infection. In this study, we used the publicly available complete genome sequences of C. trachomatis and performed comparative proteomics and reverse vaccinology analyses to explore novel drug and vaccine targets against this devastating pathogen. We identified 713 core proteins from 71 C. trachomatis complete genome sequences and prioritized them based on their cellular essentiality, virulence, and available antibiotic resistance. The analyses led to the identification of 16 pathogen-specific proteins with no resolved 3D structures, though holding significant druggable potential. The sequences of the three shortlisted candidates' membrane proteins were used for designing vaccine constructs. The antigenicity, toxicity, and solubility profile-based lead epitopes were prioritized for multi-epitope-based vaccine constructs in combination with specific linkers, PADRE sequences, and molecular adjuvants for immunogenicity enhancement. The molecular-level interactions of the prioritized vaccine construct with human immune cells HLA and TLR4/MD were validated by molecular docking and molecular dynamic simulation analyses. Furthermore, the cloning and expression potential of the lead vaccine construct was predicted in the E. coli cloning vector system. Additional testing and experimental validation of these multi-epitope constructs appear promising against C. trachomatis-mediated infection.

The In Silico Characterization of a Salicylic Acid Analogue Coding Gene Clusters in Selected Pseudomonas fluorescens Strains.

BACKGROUND: The microbial genome sequences provide solid in silico framework for interpretation of their drug-like chemical scaffolds biosynthetic potentials. Pseudomonas fluorescens strains are metabolically versatile and producing therapeutically important natural products. OBJECTIVES: The key objective of the present study was to mine the publically available data of P. fluorescens strains genomes for putative drug-like metabolites identification. MATERIALS AND METHODS: We implemented the computational biology resources of AntiSMASH and BAGEL3 for the secondary metabolites prediction from P. fluorescens strains genome sequences. The predicted secondary metabolites were evaluated using drug discovery chemoinformatics resources, like Drugbank database search and molecular docking inspection. RESULTS: The analyses unveiled a wide array of chemical scaffolds biosynthesis in different P. fluorescens strains. Subsequently, the drug-like potential evaluation of these metabolites identified few strains, including P. fluorescens PT14, P. fluorescens A5O6, and P. fluorescens FW300-N2E3 that harbor the biosynthetic gene clusters for salicylic acid-like metabolite biosynthesis. The molecular docking inspection of this metabolite against human cyclooxygenase and aldo-keto reductase targets revealed its feasible inhibitory potentials like other salicylate compounds. CONCLUSION: The computational biology and drug discovery analyses identified different gene clusters in P. fluorescens genomes coding for salicylic acid-like chemotypes biosynthesis. These gene clusters may worthy to target through metabolic engineering for the massive production of salicylates-like chemical scaffolds from microbial resources.