Project description:We discovered SW033291 in a high throughput chemical screen aimed at identifying 15-prostaglandin dehydrogenase (15-PGDH) modulators. The compound exhibited inhibitory activity in in vitro biochemical and cell-based assays of 15-PGDH activity. We subsequently demonstrated that this compound, and several analogs thereof, are effective in in vivo mouse models of bone marrow transplant, colitis, and liver regeneration, where increased levels of PGE2 positively potentiate tissue regeneration. To better understand the binding of SW033291, we carried out docking studies for both the substrate, PGE2, and an inhibitor, SW033291, to 15-PGDH. Our models suggest similarities in the ways that PGE2 and SW033291 interact with key residues in the 15-PGDH-NAD+ complex. We carried out molecular dynamics simulations (MD) of SW033291 bound to this complex, in order to understand the dynamics of the binding interactions for this compound. The butyl side chain (including the sulfoxide) of SW033291 participates in crucial binding interactions that are similar to those observed for the C15-OH and the C16-C20 alkyl chain of PGE2. In addition, interactions with residues Ser138, Tyr151, and Gln148 play key roles in orienting and stabilizing SW033291 in the binding site and lead to enantioselectivity for the R-enantiomer. Finally, we compare the binding mode of (R)-S(O)-SW033291 with the binding interactions of published 15-PGDH inhibitors.
Project description:Malignant mesothelioma (MM) is a highly aggressive and resistant tumor. The prognostic role of key effectors of glycolytic metabolism in MM prompted our studies on the cytotoxicity of new inhibitors of glucose transporter type 1 (GLUT-1) and lactate dehydrogenase-A (LDH-A) in relation to ATP/NAD+ metabolism, glycolysis and mitochondrial respiration. The antiproliferative activity of GLUT-1 (PGL13, PGL14) and LDH-A (NHI-1, NHI-2) inhibitors, alone and in combination, were tested with the sulforhodamine-B assay in peritoneal (MESO-II, STO) and pleural (NCI-H2052 and NCI-H28) MM and non-cancerous (HMEC-1) cells. Effects on energy metabolism were measured by both analysis of nucleotides using RP-HPLC and evaluation of glycolysis and respiration parameters using a Seahorse Analyzer system. All compounds reduced the growth of MM cells in the µmolar range. Interestingly, in H2052 cells, PGL14 decreased ATP concentration from 37 to 23 and NAD+ from 6.5 to 2.3 nmol/mg protein. NHI-2 reduced the ATP/ADP ratio by 76%. The metabolic effects of the inhibitors were stronger in pleural MM and in combination, while in HMEC-1 ATP reduction was 10% lower compared to that of the H2052 cells, and we observed a minor influence on mitochondrial respiration. To conclude, both inhibitors showed cytotoxicity in MM cells, associated with a decrease in ATP and NAD+, and were synergistic in the cells with the highest metabolic modulation. This underlines cellular energy metabolism as a potential target for combined treatments in selected cases of MM.
Project description:Mitochondrial sn-glycerol 3-phosphate dehydrogenase (mGPDH) is a ubiquinone-linked enzyme in the mitochondrial inner membrane best characterized as part of the glycerol phosphate shuttle that transfers reducing equivalents from cytosolic NADH into the mitochondrial electron transport chain. Despite the widespread expression of mGPDH and the availability of mGPDH-null mice, the physiological role of this enzyme remains poorly defined in many tissues, likely because of compensatory pathways for cytosolic regeneration of NAD⁺ and mechanisms for glycerol phosphate metabolism. Here we describe a novel class of cell-permeant small-molecule inhibitors of mGPDH (iGP) discovered through small-molecule screening. Structure-activity analysis identified a core benzimidazole-phenyl-succinamide structure as being essential to inhibition of mGPDH while modifications to the benzimidazole ring system modulated both potency and off-target effects. Live-cell imaging provided evidence that iGPs penetrate cellular membranes. Two compounds (iGP-1 and iGP-5) were characterized further to determine potency and selectivity and found to be mixed inhibitors with IC₅₀ and K(i) values between ∼1-15 µM. These novel mGPDH inhibitors are unique tools to investigate the role of glycerol 3-phosphate metabolism in both isolated and intact systems.
Project description:In order to determine whether dis-regulation of a genetic pathway could explain the increased apoptosis of parp-2-/- double positive thymocytes, the gene expression profiles in double positive thymocytes derived from wild-type and parp-2-/- mice were analysed using Affymetrix oligonucleotide chips (mouse genome 430 2.0).
Project description:The enzyme 6-phosphogluconate dehydrogenase is a potential drug target for the parasitic protozoan Trypanosoma brucei, the causative organism of human African trypanosomiasis. This enzyme has a polar active site to accommodate the phosphate, hydroxyl and carboxylate groups of the substrate, 6-phosphogluconate. A virtual fragment screen was undertaken of the enzyme to discover starting points for the development of inhibitors which are likely to have appropriate physicochemical properties for an orally bioavailable compound. A virtual screening library was developed, consisting of compounds with functional groups that could mimic the phosphate group of the substrate, but which have a higher pKa. Following docking, hits were clustered and appropriate compounds purchased and assayed against the enzyme. Three fragments were identified that had IC50 values in the low micromolar range and good ligand efficiencies. Based on these initial hits, analogues were procured and further active compounds were identified. Some of the fragments identified represent potential starting points for a medicinal chemistry programme to develop potent drug-like inhibitors of the enzyme.
Project description:Impaired availability of the amino acid aspartate can be a metabolic constraint of cell proliferation in diverse biological contexts. However, the kinetics of aspartate depletion, and its ramifications on downstream metabolism and cell proliferation, remain poorly understood. Here, we deploy the aspartate biosensor jAspSnFR3 with live cell imaging to resolve temporal relationships between aspartate and cell proliferation from genetic, pharmacological, and nutritional manipulations. In cells with impaired aspartate acquisition from mitochondrial complex I inhibition or constrained uptake in aspartate auxotrophs, we find that the proliferation defects lag changes in aspartate levels and only manifest once aspartate levels fall below a critical threshold, supporting the functional link between aspartate levels and cell proliferation in these contexts. In another context of aspartate synthesis inhibition, impairing succinate dehydrogenase (SDH), we find a more complex metabolic interaction, with initial aspartate depletion followed by a rebound of aspartate levels over time. We find that this aspartate rebound effect results from SDH inhibition disproportionately impairing pyrimidine synthesis by inhibiting aspartate transcarbamoylase (ATCase) through the dual effect of diminishing aspartate substrate availability while accumulating succinate, which functions as a competitive inhibitor of aspartate utilization. Finally, we uncover that the nucleotide imbalance from SDH inhibition causes replication stress and introduces a vulnerability to ATR kinase inhibition. Altogether, these findings identify a mechanistic role for succinate in modulating nucleotide synthesis and demonstrate how cascading metabolic interactions can unfold to impact cell function.
Project description:Cryptosporidium parvum is a highly prevalent zoonotic and anthroponotic protozoan parasite that causes a diarrheal syndrome in children and neonatal livestock, culminating in growth retardation and mortalities. Despite the high prevalence of C. parvum, there are no fully effective and safe drugs for treating infections, and there is no vaccine. We have previously reported that the bacterial-like C. parvum lactate dehydrogenase (CpLDH) enzyme is essential for survival, virulence and growth of C. parvum in vitro and in vivo. In the present study, we screened compound libraries and identified inhibitors against the enzymatic activity of recombinant CpLDH protein in vitro. We tested the inhibitors for anti-Cryptosporidium effect using in vitro infection assays of HCT-8 cells monolayers and identified compounds NSC158011 and NSC10447 that inhibited the proliferation of intracellular C. parvum in vitro, with IC50 values of 14.88 and 72.65 μM, respectively. At doses tolerable in mice, we found that both NSC158011 and NSC10447 consistently significantly reduced the shedding of C. parvum oocysts in infected immunocompromised mice's feces, and prevented intestinal villous atrophy as well as mucosal erosion due to C. parvum. Together, our findings have unveiled promising anti-Cryptosporidium drug candidates that can be explored further for the development of the much needed novel therapeutic agents against C. parvum infections.
Project description:Ossification of the posterior longitudinal ligament (OPLL) is formed by heterogeneous ossification of posterior longitudinal ligament. The patho-mechanism of OPLL is still largely unknown. MicroRNAs are small nucleatides that function as regulators of gene expression in almost any biological process. However, few microRNAs are reported to have a role in the pathological process of OPLL. Therefore, we performed high-throughput microRNA sequencing and transcriptome sequencing of primary OPLL and PLL cells in order to decipher the interacting network of microRNAs in OPLL. MRNA and microRNA profiles were done using primary culture cells of human ossification of the posterior longitudinal ligament (OPLL) tissue and normal posterior longitudinal ligament (PLL) tissue.
Project description:Our study investigated the impact of CD47 gene deletion on protein acetylation and its regulatory effects on mitochondrial metabolism and function in the skeletal muscle of mice.
Project description:Fifteen novel pyridine carboxamide derivatives bearing a diarylamine-modified scaffold were designed, synthesized, and their antifungal activity was evaluated. Preliminary bioassay results showed that some of the synthesized compounds exhibited moderate to good in vitro antifungal activity. Further, compound 6-chloro-N-(2-(phenylamino)phenyl)nicotinamide (3f) displayed good in vivo antifungal activity against Botrytis cinerea. The enzymatic test on B. cinerea succinate dehydrogenase (SDH) showed that the inhibitory activity possessed by compound 3f equally matches that of thifluzamide. Molecular docking results demonstrated that compound 3f could commendably dock with the active site of SDH via stable hydrogen bonds and hydrophobic interactions, suggesting the possible binding modes of the title compounds with SDH. The results above revealed that the target compounds would be the leading fungicide compound for further investigation.