Abstract: The epidemiology of cryptosporidiosis in southern Africa is largely unknown. The disease is associated with diarrhea and nutritional deficiencies, leading to severe morbidity and mortality among immune-compr...
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Abstract: The epidemiology of cryptosporidiosis in southern Africa is largely unknown. The disease is associated with diarrhea and nutritional deficiencies, leading to severe morbidity and mortality among immune-compromised patients. This study aimed to assess the pooled prevalence of Cryptosporidium spp. infection among immune-compromised humans in southern Africa over the past 20 years. Reports of Cryptosporidium spp. infection in humans published between 2000 and 2020 using Google Scholar, PubMed, Ovid Medline, African Journal Online (AJOL), and Web of Science literature databases were obtained. Inclusion criteria of sorted articles for Cryptosporidium spp. infection were standardized using preferred reporting items for systematic reviews and meta-analyses (PRISMA) checklist. A total of 22 eligible studies were sorted for meta-analysis. Overall prevalence of Cryptosporidium spp. infection in southern African countries with reports was 16.8% (95% CI 9.7–25.3). Sub-group analysis showed a pooled prevalence of 25.2, 20.5, and 17.9% among HIV/AIDS patients, children, and diarrhoeic individuals, respectively. Pooled prevalence was highest in South Africa and lowest in Zimbabwe across examined individuals. The pooled prevalence of Cryptosporidium spp. infections in diarrhoeic patients was highest in individuals from Botswana (17.6%) which is significantly different (Χ2 = 9.337;P = 0.002) from South Africans (12.7%). South African individuals with HIV/AIDS showed the highest pooled prevalence of Cryptosporidium infections than other countries. The high prevalence of Cryptosporidium spp. infections among immune-compromised patients in southern Africa showed that the pathogen is of significant importance in this region. Continuous studies on the genetic characterization of Cryptosporidium spp. isolates and associated risk factors are needed across southern Africa to identify the predominant subtypes in humans. Graphic abstract: [Figure not available: see fullte
Targeting undruggable proteins and challenging binding sites, such as protein–protein interaction (PPI) interfaces and allosteric pockets, using small-molecule inhibitors is often infeasible. Peptide-based irreversib...
Targeting undruggable proteins and challenging binding sites, such as protein–protein interaction (PPI) interfaces and allosteric pockets, using small-molecule inhibitors is often infeasible. Peptide-based irreversible inhibitors are promising emerging strategies for the treatment of such targets. However, there is currently no systematic in silico protocol for the rational design of peptide-based covalent inhibitors. We developed a streamlined computational framework for the de novo design of peptide-based irreversible inhibitors. Key considerations include peptide sequence optimization for binding, selection of electrophilic warheads, peptide folding, target specificity, and pharmacokinetic and toxicity profiles. Binding affinities were estimated using covalent molecular dynamics (MDcov) simulations and thermodynamic binding free energy calculations. Using KRASG12C, a strategic drug target traditionally considered undruggable, as a case study, the protocol identified top-hit peptide inhibitors (RVKDX, HVKXR, and XLKDH) with binding free energies (BFEs) of -48.84, -48.93, and -48.67 kcal/mol, respectively. These values are comparable to sotorasib (-50.63 kcal/mol) and lower than adagrasib (-71.73 kcal/mol), both FDA-approved KRASG12C inhibitors. Benchmarking against BTK481C using zanubrutinib, an FDA-approved therapeutic agent for B-cell malignancies, further validated the protocol. Peptide inhibitors XDYMA, XDYVL, and QDWXL demonstrated BFEs of -83.40, -76.69, and -62.40 kcal/mol, outperforming zanubrutinib (-57.00 kcal/mol), acalabrutinib (-54.19 kcal/mol), and ibrutinib (-55.09 kcal/mol). These findings underscore the robustness and adaptability of our protocol, offering a systematic, multifaceted approach that can be integrated into drug discovery workflows to design novel peptide-based irreversible inhibitors.
After decades of leaving patients with limited treatment options due to the ‘undruggability’ of Kirsten rat sarcoma, the kernel was finally cracked with the discovery of Sotorasib. This novel drug binds to a small p...
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Mutations in isocitrate dehydrogenase enzymes 1 and 2 (mIDH1/2) results in an aberrant accumulation of (R)-2-hydroxyglutarate (2-HG), excess of which has been shown to inhibit alpha ketoglutarate (αKG)-dependent enzy...
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The effort to eradicate malaria has not yet been achieved, and the parasitic infection remains a global challenge. The burden stems from the worldwide dissemination of parasites resistant to commonly used chemotherape...
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The effort to eradicate malaria has not yet been achieved, and the parasitic infection remains a global challenge. The burden stems from the worldwide dissemination of parasites resistant to commonly used chemotherapeutics and the scarcity of the malaria vaccine, Mosquirix. In the quest to augment malaria treatment, current focus has been geared towards plasmepsin (P). These classes of aspartic acid proteases are expressed at multiple stages of the parasite's life cycle and are implicated in host haemoglobin degradation and parasite dissemination in vivo;elaborating their essentiality as therapeutic targets. Our earlier research examined the structural dynamics of WM382, a novel antimalarial compound, in relation to its enzyme inhibitory mechanism on plasmepsin IX (PMIX) and plasmepsin X (PMX). WM382 inflicts structural compactness on both proteases. The pharmacophoric moieties of WM382 were used in the present study to search the Zinc database for WM382 derivatives. The leads, ZINC06868602, ZINC09431717 and ZINC13367223 formed strong intermolecular bonds with the catalytic dyad Asp32 and Asp281. The flap regions generally move away from the binding pocket, divulging the active site to the inhibitor and keeping it near to the catalytic dyad. However, upon binding of the leads, the flap residues wrapped inward to surround the inhibitors, further restricting the characteristic twist motion of these proteases for enzyme activity. Likewise, for the experimental drug candidate WM382, the identified leads displayed high affinity for PMIX, with total binding free energies of leads estimated to be −33.45 kcal/mol, −30.33 kcal/mol and −29.67 kcal/mol, respectively. Evaluation of per residue energy composition indicated the catalytic dyad contributes immensely towards ligand binding. Results from our study suggest these compounds have better inhibitory prowess against PMIX. The potency of these chemicals should further be tested in the experimental laboratory to evaluate thei
Hunteria umbellate (K. Schum.) Hallier f. (Apocynaceae) is a tropical rainforest tree commonly found in sub-Saharan region of Africa. It is a useful and very popular plant among the locals due to the outstanding anti-...
Hunteria umbellate (K. Schum.) Hallier f. (Apocynaceae) is a tropical rainforest tree commonly found in sub-Saharan region of Africa. It is a useful and very popular plant among the locals due to the outstanding anti-diabetic activity of the seeds. A comprehensive literature search on articles published on phytochemical analysis and various pharmacological activities of Hunteria umbellate was carried out using search engines such as Google Scholar, PubMed and Science Direct. In this review, it was deduced that H. umbellate is employed in folk medicine as an elixir for obesity, fever, leprosy sores, menstrual pain, infertility, yaws, intestinal worms, abdominal discomfort and stomach ache. Due to their durability and immunity against termites, the stems are coveted and desired as timbers in the construction of houses, while the bark has been reportedly exported to Europe for medicinal uses. Pharmacological activities such as fertility enhancing, aphrodisiac, hypoglycemic, anti-inflammatory, has been ascribed to the different morphological organs of H. umbellate. Moreover, compounds belonging to important classes of secondary metabolites with biological activities such as triterpenoids, flavonoids, tannins, alkaloids, quinic acids have been identified and characterized from the plant. From this review, it can be inferred that, numerous and bioactive principles with known biological usefulness are present in the extracts of H. umbellate and might be responsible for the observed biological and pharmacological activities.
Dihydrofolate reductase (DHFR) enzyme regulates de-novo folate synthesis in Plasmodium falciparum, hence considered a critical malaria drug target. Pyrimethamine inhibits DHFR, but resistance and lack of cross-species...
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The unprecedented occurrence of malaria and the increase rate of parasite resistance to current therapeutics have over the past decade elicited researchers’ interest in probing novel drug targets and unabatedly searc...
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The unprecedented occurrence of malaria and the increase rate of parasite resistance to current therapeutics have over the past decade elicited researchers’ interest in probing novel drug targets and unabatedly searching for competitive inhibitors. Plasmepsin (PM) family of aspartic proteases has recently been at the forefront in this pursuit to augment malaria treatment. In malaria infections engineered by P. falciparum, PMIX and PMX are highlighted as mediators of egress, invasion and spread of the infection in humans. Despite these proteases' druggability, there is currently no authorized inhibitor. WM382, a small molecule inhibitor, has been demonstrated to have dual inhibitory properties against both proteases, which is promising. However, the structural dynamics associated with the dual inhibition mechanism remain unclear. As such, we employed integrative computer-assisted atomistic techniques to provide thorough structural dynamic insights. The binding WM382 confers structural stability on both proteases through a mesh of hydrogen and hydrophobic interactions with binding site residues. The overall binding energies of PMIX and PMX were estimated to be −27.27 kcal/mol and −23.95 kcal/mol respectively, however, the trademark aspartic acid residues in the binding pocket of these proteases contributed minimally to this effect. WM382 increased structural flexibility creating excessively loose conformation that distorts the characteristic “twist motion” of the members of the plasmepsin family. These assimilated conformations further affect the biological role of both proteases. Energy decomposition analysis proved that Phe77/Phe75 contributed significantly to the overall binding of WM382 within the binding pockets of both PMIX and PMX eliciting strong intermolecular interactions, thus favouring binding affinity. The stable orientations of WM382 within the respective hydrophobic pockets allowed favorable interactions with binding site residues which accounted for it
Chronic stress is a risk factor for depression and is characterized by elevated levels of brain monoamine oxidase A (MAOA). Mounting evidence has shown that MAOA is a biochemical link between stress and depression. Ap...
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Genomic techniques such as next-generation sequencing and microarrays have facilitated the identification and classification of molecular signatures inherent in cells upon viral infection, for possible therapeutic tar...
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