-
International Journal of Molecular... Jun 2020Chagas disease, caused by (), affects nearly eight million people worldwide. There are currently only limited treatment options, which cause several side effects and...
Chagas disease, caused by (), affects nearly eight million people worldwide. There are currently only limited treatment options, which cause several side effects and have drug resistance. Thus, there is a great need for a novel, improved Chagas treatment. Bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) has emerged as a promising pharmacological target. Moreover, some human dihydrofolate reductase (DHFR) inhibitors such as trimetrexate also inhibit DHFR-TS (DHFR-TS). These compounds serve as a starting point and a reference in a screening campaign to search for new DHFR-TS inhibitors. In this paper, a novel virtual screening approach was developed that combines classical docking with protein-ligand interaction profiling to identify drug repositioning opportunities against infection. In this approach, some food and drug administration (FDA)-approved drugs that were predicted to bind with high affinity to DHFR-TS and whose predicted molecular interactions are conserved among known inhibitors were selected. Overall, ten putative DHFR-TS inhibitors were identified. These exhibited a similar interaction profile and a higher computed binding affinity, compared to trimetrexate. Nilotinib, glipizide, glyburide and gliquidone were tested on epimastigotes and showed growth inhibitory activity in the micromolar range. Therefore, these compounds could lead to the development of new treatment options for Chagas disease.
Topics: Chagas Disease; Computer Simulation; Drug Repositioning; Folic Acid Antagonists; Glipizide; Glyburide; Humans; Ligands; Molecular Docking Simulation; Molecular Structure; Pyrimidines; Structure-Activity Relationship; Sulfonylurea Compounds; Trypanocidal Agents; Trypanosoma cruzi
PubMed: 32560043
DOI: 10.3390/ijms21124270 -
Viruses May 2023During the COVID-19 pandemic, drug repurposing represented an effective strategy to obtain quick answers to medical emergencies. Based on previous data on methotrexate...
During the COVID-19 pandemic, drug repurposing represented an effective strategy to obtain quick answers to medical emergencies. Based on previous data on methotrexate (MTX), we evaluated the anti-viral activity of several DHFR inhibitors in two cell lines. We observed that this class of compounds showed a significant influence on the virus-induced cytopathic effect (CPE) partly attributed to the intrinsic anti-metabolic activity of these drugs, but also to a specific anti-viral function. To elucidate the molecular mechanisms, we took advantage of our EXSCALATE platform for in-silico molecular modelling and further validated the influence of these inhibitors on nsp13 and viral entry. Interestingly, pralatrexate and trimetrexate showed superior effects in counteracting the viral infection compared to other DHFR inhibitors. Our results indicate that their higher activity is due to their polypharmacological and pleiotropic profile. These compounds can thus potentially give a clinical advantage in the management of SARS-CoV-2 infection in patients already treated with this class of drugs.
Topics: Humans; SARS-CoV-2; COVID-19; Pandemics; Molecular Docking Simulation; Antiviral Agents; Drug Repositioning
PubMed: 37243214
DOI: 10.3390/v15051128 -
Bioorganic & Medicinal Chemistry Letters Aug 2019Pneumocystis pneumonia (PCP) caused by Pneumocystis jirovecii (pj) can lead to serious health consequences in patients with an immunocompromised system. Trimethoprim...
Pneumocystis pneumonia (PCP) caused by Pneumocystis jirovecii (pj) can lead to serious health consequences in patients with an immunocompromised system. Trimethoprim (TMP), used as first-line therapy in combination with sulfamethoxazole, is a selective but only moderately potent pj dihydrofolate reductase (pjDHFR) inhibitor, whereas non-clinical pjDHFR inhibitors, such as, piritrexim and trimetrexate are potent but non-selective pjDHFR inhibitors. To meet the clinical needs for a potent and selective pjDHFR inhibitor for PCP treatment, fourteen 6-substituted pyrido[3,2-d]pyrimidines were developed. Comparison of the amino acid residues in the active site of pjDHFR and human DHFR (hDHFR) revealed prominent amino acid differences which could be exploited to structurally design potent and selective pjDHFR inhibitors. Molecular modeling followed by enzyme assays of the compounds revealed 15 as the best compound of the series with an IC of 80 nM and 28-fold selectivity for inhibiting pjDHFR over hDHFR. Compound 15 serves as the lead analog for further structural variations to afford more potent and selective pjDHFR inhibitors.
Topics: Folic Acid Antagonists; Humans; Models, Molecular; Pneumocystis; Pneumocystis carinii; Pyrimidines; Structure-Activity Relationship; Trimethoprim
PubMed: 31176699
DOI: 10.1016/j.bmcl.2019.06.004 -
The Journal of Biological Chemistry Dec 2019The endoplasmic reticulum-associated degradation (ERAD) pathway mediates the endoplasmic reticulum-to-cytosol retrotranslocation of defective proteins through protein...
The endoplasmic reticulum-associated degradation (ERAD) pathway mediates the endoplasmic reticulum-to-cytosol retrotranslocation of defective proteins through protein complexes called retrotranslocons. Defective proteins usually have complex conformations and topologies, and it is unclear how ERAD can thread these conformationally diverse protein substrates through the retrotranslocons. Here, we investigated the substrate conformation flexibility necessary for transport via retrotranslocons on the ERAD-L, ERAD-M, and HIV-encoded protein Vpu-hijacked ERAD branches. To this end, we appended various ERAD substrates with specific domains whose conformations were tunable in flexibility or tightness by binding to appropriate ligands. With this technique, we could define the capacity of specific retrotranslocons in disentangling very tight, less tight but well-folded, and unstructured conformations. The Hrd1 complex, the retrotranslocon on the ERAD-L branch, permitted the passage of substrates with a proteinase K-resistant tight conformation, whereas the E3 ligase gp78-mediated ERAD-M allowed passage only of nearly completely disordered but not well-folded substrates and thus may have the least unfoldase activity. Vpu-mediated ERAD, containing a potential retrotranslocon, could unfold well-folded substrates for successful retrotranslocation. However, substrate retrotranslocation in Vpu-mediated ERAD was blocked by enhanced conformational tightness of the substrate. On the basis of these findings, we propose a mechanism underlying polypeptide movement through the endoplasmic reticulum membrane. We anticipate that our biochemical system paves the way for identifying the factors necessary for the retrotranslocation of membrane proteins.
Topics: Endoplasmic Reticulum; Endoplasmic Reticulum-Associated Degradation; HEK293 Cells; Human Immunodeficiency Virus Proteins; Humans; Leupeptins; Proteasome Endopeptidase Complex; Protein Unfolding; Receptors, Autocrine Motility Factor; Substrate Specificity; Trimetrexate; Ubiquitin-Protein Ligases; Viral Regulatory and Accessory Proteins
PubMed: 31748412
DOI: 10.1074/jbc.RA119.010019