Mode of action studies for a novel anti-leishmania compound
ABSTRACT: We describe the development of a novel anti-leishmanial drug-like chemical series based on a pyrazolopyrimidine scaffold. The leading compound is efficacious in a mouse model of visceral leishmaniasis, and has suitable physicochemical, pharmacokinetic and toxicological properties for further development and has been declared a preclinical candidate. Detailed mode of action studies indicate that compounds from this series act principally by inhibiting the parasite protein kinases.
Project description:As a test of trypanosome transcriptome responsiveness, we analysed the effects of over-expression of the early endosome small GTPase Rab5A in procyclic form T.brucei, which results in significant augmentation of fluid phase and receptor-mediated endocytic activity (Pal et al. 2002).<br><br>part 1: 2 PCFWT and 2 PCF5AWT-OE (PCF cell lines over-expressing a wildtype version of RAB5A) biological replicates, as well as dye swaps were used.<br><br>part 2: 2 PCFWT and 2 PCF5AQL-OE (PCF cell lines over-expressing a mutant version of RAB5A locked in the GTP-bound state) biological replicates, as well as dye swaps were used.<br><br>part 3: 2 PCFWT and 2 PCF5BQL-OE (PCF cell lines over-expressing a mutant version of RAB5B locked in the GTP-bound state) biological replicates, as well as dye swaps were used.
Project description:T. brucei PF cells were treated with several chemical reagents and anti-trypanosomatid drugs. The effect of each chemical perturbation on the transcriptome of T. brucei was examined by transcript profiling of treated vs. control cells. The results indicated widespread changes, suggesting that the transcriptome of T. brucei is highly responsive to environmental factors that perturb its metabolic and biological pathways. 11 chemical perturbations, each co-hybridized with a common reference RNA from control non-treated cells. One array per treatment.
Project description:Fusobacterium nucleatum is a Gram negative oral bacterial species associated with periodontal disease progression. This species is perhaps best known for its ability to adhere to a vast array of other bacteria and eukaryotic cells. Numerous studies of F. nucleatum have examined various coaggregation partners and inhibitors, but it is largely unknown whether these interactions induce a particular genetic response. We tested coaggregation between F. nucleatum ATCC strain 25586 and various species of Streptococcus in the presence of a semi-defined growth medium containing saliva. We found that this condition could support efficient coaggregation, but surprisingly also stimulated a similar degree of autoaggregation. We further characterized the autoaggregation response, since few reports have examined this in F. nucleatum. After screening several common coaggregation inhibitors, we identified L-lysine as a competitive inhibitor of autoaggregation. We performed a microarray analysis of the planktonic vs. autoaggregated cells and found nearly 100 genes that were affected after only about 60 min. of aggregation. We tested a subset of these genes via real-time RT-PCR and confirmed the validity of the microarray results. Some of these genes were also found to be inducible in cell pellets created by centrifugation. Based upon these data, it appears that autoaggregation activates a genetic program that may be utilized for growth in a high cell density environment, such as the oral biofilm. The study aims to determine the effect of autoaggregation upon the transcriptome. The study contains 2 separate experiments that both measure dispersed (i.e. non-aggregated) vs. aggregated cells and each experiment was performed in duplicate. Samples with no added components other than medium were dispersed, samples containing 25% saliva were aggregated, and samples containing 25% saliva + 50mM L-lysine remained dispersed.
Project description:Small non-coding RNA biogenesis typically involves cleavage of structured precursors by RNase III-like endonucleases. However, guide RNAs that direct U-insertion/deletion mRNA editing in mitochondria of trypanosomes maintain 5′ triphosphate characteristic of transcription start site and possess U-tail indicative of 3′ processing and uridylation. Here, we identified a protein complex composed of RET1 TUTase and 3′-5′ DSS1 exonuclease, and three additional subunits. This complex, termed mitochondrial 3′ processome (MPsome), is responsible for primary uridylation of ~800-nt gRNA precursors, their processive degradation to a mature length of 50-60 nt, and secondary U-tail addition. Both strands of gRNA gene are transcribed giving rise to sense and antisense precursors of similar size. Head-to-head hybridization of these transcripts blocks symmetrical 3′-5′ degradation at the fixed distance from the double-stranded region. Together, our findings suggest a model in which gRNA is derived from the 5′ extremity of a primary molecule by uridylation-induced, antisense transcription-controlled exonucleolytic degradation. 1. we first sequenced guide RNA precursor (Gel-fractioned total cellular RNA 600-1500nt was used) transcripts from three replicates to study the their tail features and also validate observation of sense/antisense accumulation upon perturbation of pre-processing complex based on few cases. 2. we then sequenced mitochondrial small RNA and built a reference for small RNAs using our custom algorithm. We then took the mitochondrial small RNA data and uncovered the sense/antisense pair. 3. We then used CLIP-Seq data to investigate in vivo binding sites and, together with RNA IP-Seq data to understand what determine the relative abundance of sense and antisense pair of the duplex. 4. We used sequenced small mitochondrial RNA in different RNAi experiments (For RNAi experiments, 30-70nt RNA fraction was gel-isolated from total cellular RNAs) to understand which protein will affect the Utail length in mature small mitochondrial RNA.
Project description:Whole genome comparison of RNA levels for both protein coding genes and structural RNAs in five different life cycle stages: in vivo slender bloodstream form, in vivo stumpy bloodstream form, cultured bloodstream form, log-phase procyclic culture form and stationary-phase procyclic culture form RNA from three independent biological replicates from five different life cycle stages were hybridized to Nimblegen arrays (Madison,WI USA) that contained 8 probes per open reading frame and 3 probes per structural RNA spotted three times per array
Project description:The cell division cycle of the unicellular eukaryote Trypanosome brucei is tightly regulated despite the paucity of transcriptional control that results from the arrangement of genes in polycistronic units and lack of dynamically regulated transcription factors. To identify the contribution of dynamic phosphorylation to T. brucei cell cycle control we have combined cell cycle synchronisation by centrifugal elutriation with SILAC quantitative phosphoproteomic analysis. Cell cycle regulated changes in phosphorylation site abundance (917 sites, average 5-fold change) were more widespread and of a larger magnitude than changes in protein abundance (443 proteins, average 2-fold change) and were mostly independent of each other. Hierarchical clustering of co-regulated phosphorylation sites according to their cell cycle profile revealed a bulk increase in phosphorylation occurs across the cell cycle, with a significant enrichment of known cell cycle regulators and RNA binding proteins (RBPs) within the largest clusters. Cell cycle regulated changes in essential cell cycle kinases is temporally co-ordinated with differential phosphorylation of components of the kinetochore and eukaryotic initiation factors, along with many RBPs not previously linked to the cell cycle such as eight PSP1-C terminal domain containing proteins. The temporal profiles demonstrate the importance of dynamic phosphorylation in co-ordinating progression through the cell cycle, and provides evidence that RBPs play a central role in post-transcriptional gene regulation of the T. brucei cell cycle.
Project description:A tagged ectopic version of the ELAV-like protein Tb927.8.6650 of T. brucei was expressed in stable cell lines and pulled down. Co-purifying transcripts were analyzed by sequencing to identify RNAs associated with Tb927.8.6650. Stable procyclic form cell lines expressing tetracycline-inducible TAP-tagged Tb927.8.6650 were created. Cells were harvested 48h after tet-induction, followed by tandem affinity purification of Tb927.8.6650, extraction of co-purified RNA, and sequencing.
Project description:Rhinovirus causes the common cold and drives exacerbation in asthma and COPD, leading to substantial morbidity and healthcare cost. The single positive strand RNA genome of this non-enveloped virus is translated into a single polyprotein that is processed by virus 3C protease to form three structural capsid proteins VP0, VP1 and VP3, and other proteins required for viral life cycle completion. Capsid proteins assemble into the 5S capsid protomer, five of which form a 14S pentamer, and 12 pentamers then assemble to form the 150S icosahedral provirion into which the viral genome is incorporated. During the final step of viral maturation, VP0 is cleaved into VP2 and VP4. VP4 is encoded at the N-terminus of the viral polyprotein, and in many Picornaviruses is N-myristoylated by host cell N-myristoyltransferase (NMT). We have explored the impact of IMP-1088 (the first sub-nanomolar IC50 dual inhibitor of human N-myristoyl transferases HsNMT1 and HsNMT2) on HRV capsid myristoylation in cells. Global identification of proteins for which myristoylation is selectively inhibited by IMP-1088 was performed by quantitative chemical proteomic analysis of YnMyr-tagged proteins in HeLa cells infected with RV16 treated with 50 nM IMP-1088 or vehicle (DMSO). Proteins were subjected to ligation to AzRB, an azide capture reagent bearing a trypsin-cleavable linker and biotin dual label followed by affinity enrichment on Neutravidin beads, on-bead digestion with trypsin, nanoLC-MS/MS analysis of tryptic peptides, and data processing by label-free protein quantification (LFQ) in MaxQuant. 60 N-myristoylated proteins were identified, including the RV16 polyprotein which responded to IMP-1088 inhibition, with no significant change in protein abundances across the whole proteome in the presence of inhibitor. The majority of viral capsid peptides identified in the pull-down mapped to the VP0 domain of the polyprotein, and the N-terminal YnMyr-tagged peptide was readily identified by MS/MS. These data provide the first direct evidence for HRV capsid myristoylation in human cells, and demonstrate that this lipid modification is highly susceptible to inhibition by a selective NMT inhibitor.
Project description:Sulforaphane is a small molecule isothiocyanate which exhibits anticancer potential, yet its biological targets remain poorly understood. Here we employ a competition-based chemical proteomics strategy to profile sulforaphane’s targets and identify over 500 targets along with their relative affinities. These targets provide a new set of mediators for sulforaphane’s bioactivity, and aid understanding of its complex mode of action.