Project description:Exploration and Characterization of the Antimalarial Activity of Cyclopropyl Carboxamides that Target the Mitochondrial Protein, Cytochrome b
Project description:Choline analogs represent a novel class of antimalarial compounds with strong potency against drug-sensitive and resistant P. falciparum. Although, these drugs are presumed to target proteins within lipid biosynthesis pathways; their complete mechanism of action and the parasite’s compensatory response remain to be elucidated. We have applied transcriptional profiling to characterize the global response to the choline analog T4 during the P. falciparum intraerythrocytic life cycle Keywords: Trascriptome analysis of Plasmodium falciparum in response to external stimuli using the affymetrix platform GPL3575
Project description:Malaria, caused by Plasmodium falciparum, remains a significant health burden. The barrier for developing anti-malarial drugs is the ability of the parasite to rapidly generate resistance. We previously demonstrated that Salinipostin A (SalA), a natural product, potently kills parasites by inhibiting multiple lipid metabolizing serine hydrolases, a mechanism with a low propensity for resistance. Given the difficulty of employing natural products as therapeutic agents, we synthesized a small library of lipidic mixed alkyl/aryl phosphonates as bioisosteres of SalA. Two constitutional isomers exhibited divergent anti-parasitic potencies which enabled the identification of therapeutically relevant targets. We also confirm that this compound kills parasites through a mechanism that is distinct from both SalA and the pan-lipase inhibitor, Orlistat. In addition, like SalA, our compound induces only weak resistance, attributable to mutations in a single protein involved in multidrug resistance. These data suggest that mixed alkyl/aryl phosphonates are a promising, synthetically tractable anti-malarials with a low-propensity to induce resistance.
Project description:GLABRA2 (GL2) is a class IV homeodomain leucine-zipper (HD-Zip IV) transcription factor that is critical for the differentiation of the epidermis in the plant model Arabidopsis. HD-Zip IV transcription factors are characterized by the presence of a lipid sensing domain known as START (for STeroidogenic Acute Regulatory (StAR)-related lipid Transfer). Genome-wide ChIP-seq assays were performed with seedlings expressing EYFP-tagged GL2 wild-type and mutant proteins to test whether the START domain is dispensible for DNA binding in vivo. These experiments included three START domain mutants (gl2_∆ST (listed here as gl2_dSTART), gl2_Amo, and gl2_E375G;R392M) as well as a mutant deleted for the six terminal amino acids of the HD and the entire leucine zipper (gl2_∆HD6;∆ZLZ (listed here as gl2_dZip)). Data analysis revealed DNA binding proficiency for wild-type GL2 and for all three START domain mutants whereas little or no binding was detected for gl2∆HD6;∆ZLZ and the gl2-5 null mutant control. Genomic distributions of the binding sites were similar for wild-type GL2 and the START domain mutants. Most of the ChIP-seq hits were mapped to promoter or intergenic regions, consistent with the role of GL2 as a transcriptional regulator. The relative positions of the binding sites to the transcription start sites were also similar. Gene ontology (GO) classification revealed overlapping functional classes of target genes bound by wild-type GL2 and the START domain mutants.
Project description:Lamtor1 is a protein that is required for amino acid sensing and activation of mechanistic target of rapamycin complex 1 (mTORC1) at lysosomes. The critical role of Lamtor1 in macrophage polarization has been clarified recently. However, the role of Lamtor1 in adaptive immune system has not been investigated. Here we show that Lamtor1-deficient T cells showed markedly reduced IL-2 production, decreased mTORC1 activity, and decreased expression of purine-synthesis and lipid-synthesis enzymes.
Project description:Melanoma patients with high mRNA levels of the HDL receptor SR-BI (SCARB1) reveal poor survival outcome. The aim of the study was to evaluate the role of SR-BI in cancer progression. Therefore, SR-BI was targeted either by siRNA or by using the SR-BI specific lipid transfer inhibitor BLT-1. The SR-BI knockdown specifically revealed reduced protein glycosylation, STAT5 target gene expression and EMT pathway activation. Thus, SR-BI target genes reflect the metastatic phenotype in melanoma cells. We used the transcriptome analysis to compare SR-BI depletion to BLT-1 treatment (which specifically blocks SR-BI mediated lipid transfer) in human melanoma cells.
Project description:Refinement of synaptic connections during development requires both the elimination of some inputs and the strengthening of others. It is well accepted that this competitive process takes place throughout the nervous system and relies on synaptic activity. However, the mechanisms that link activity to refinement remain largely unresolved. Here we demonstrate that refinement of preganglionic axons in sympathetic ganglia, a process that depends unequivocally on synaptic activity, involves eukaryotic initiation factor 4E binding protein (4E-BP), a protein that regulates cap-dependent translation. In mice lacking the 3 nicotinic receptor subunit, silent synapses between preganglionic axons and postsynaptic nicotinic neurons do not refine unless synaptic activity is restored, or surprisingly, when 4E-BP is absent. Our findings demonstrate that synapses can refine in the absence of synaptic activity during development and identify 4E-BP as a critical player in this process.