Browsing by Subject "Piperidines"

Now showing 1 - 5 of 5
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    The cytoplasmic prolyl-tRNA synthetase of the malaria parasite is a dual-stage target of febrifugine and its analogs
    (American Association for the Advancement of Science, 2015-05) Herman, Jonathan D.; Pepper, Lauren R.; Cortese, Joseph F.; Estiu, Guillermina; Galinsky, Kevin; Zuzarte-Luis, Vanessa; Derbyshire, Emily R.; Ribacke, Ulf; Lukens, Amanda K.; Santos, Sofia A.; Patel, Vishal; Clish, Clary B.; Sullivan, William J., Jr.; Zhou, Huihao; Bopp, Selina E.; Schimmel, Paul; Lindquist, Susan; Clardy, Jon; Mota, Maria M.; Keller, Tracy L.; Whitman, Malcolm; Wiest, Olaf; Wirth, Dyann F.; Mazitschek, Ralph; Department of Pharmacology and Toxicology, IU School of Medicine
    The emergence of drug resistance is a major limitation of current antimalarials. The discovery of new druggable targets and pathways including those that are critical for multiple life cycle stages of the malaria parasite is a major goal for developing next-generation antimalarial drugs. Using an integrated chemogenomics approach that combined drug resistance selection, whole-genome sequencing, and an orthogonal yeast model, we demonstrate that the cytoplasmic prolyl-tRNA (transfer RNA) synthetase (PfcPRS) of the malaria parasite Plasmodium falciparum is a biochemical and functional target of febrifugine and its synthetic derivative halofuginone. Febrifugine is the active principle of a traditional Chinese herbal remedy for malaria. We show that treatment with febrifugine derivatives activated the amino acid starvation response in both P. falciparum and a transgenic yeast strain expressing PfcPRS. We further demonstrate in the Plasmodium berghei mouse model of malaria that halofuginol, a new halofuginone analog that we developed, is active against both liver and asexual blood stages of the malaria parasite. Halofuginol, unlike halofuginone and febrifugine, is well tolerated at efficacious doses and represents a promising lead for the development of dual-stage next-generation antimalarials.
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    Discordant regulation of eIF2 kinase GCN2 and mTORC1 during nutrient stress
    (Oxford University Press, 2021-06-04) Misra, Jagannath; Holmes, Michael J.; Mirek, Emily T.; Langevin, Michael; Kim, Hyeong-Geug; Carlson, Kenneth R.; Watford, Malcolm; Dong, X. Charlie; Anthony, Tracy G.; Wek, Ronald C.; Biochemistry and Molecular Biology, School of Medicine
    Appropriate regulation of the Integrated stress response (ISR) and mTORC1 signaling are central for cell adaptation to starvation for amino acids. Halofuginone (HF) is a potent inhibitor of aminoacylation of tRNAPro with broad biomedical applications. Here, we show that in addition to translational control directed by activation of the ISR by general control nonderepressible 2 (GCN2), HF increased free amino acids and directed translation of genes involved in protein biogenesis via sustained mTORC1 signaling. Deletion of GCN2 reduced cell survival to HF whereas pharmacological inhibition of mTORC1 afforded protection. HF treatment of mice synchronously activated the GCN2-mediated ISR and mTORC1 in liver whereas Gcn2-null mice allowed greater mTORC1 activation to HF, resulting in liver steatosis and cell death. We conclude that HF causes an amino acid imbalance that uniquely activates both GCN2 and mTORC1. Loss of GCN2 during HF creates a disconnect between metabolic state and need, triggering proteostasis collapse.
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    Management of hypertension in advanced kidney disease
    (Wolters Kluwer, 2022) Georgianos, Panagiotis I.; Agarwal, Rajiv; Medicine, School of Medicine
    Purpose of review: The aim of this study was to present recent developments in pharmacotherapy of hypertension in patients with advanced chronic kidney disease (CKD). Recent findings: In the AMBER trial, compared with placebo, the potassium-binder patiromer mitigated the risk of hyperkalaemia and enabled more patients with uncontrolled resistant hypertension and stage 3b/4 CKD to tolerate and continue spironolactone treatment; add-on therapy with spironolactone provoked a clinically meaningful reduction of 11-12 mmHg in unattended automated office SBP over 12 weeks of follow-up. In the BLOCK-CKD trial, the investigational nonsteroidal mineralocorticoid-receptor-antagonist (MRA) KBP-5074 lowered office SBP by 7-10 mmHg relative to placebo at 84 days with a minimal risk of hyperkalaemia in patients with advanced CKD and uncontrolled hypertension. The CLICK trial showed that the thiazide-like diuretic chlorthalidone provoked a placebo-subtracted reduction of 10.5 mmHg in 24-h ambulatory SBP at 12 weeks in patients with stage 4 CKD and poorly controlled hypertension. Summary: Enablement of more persistent spironolactone use with newer potassium-binding agents, the clinical development of novel nonsteroidal MRAs with a more favourable benefit-risk profile and the recently proven blood pressure lowering action of chlorthalidone are three therapeutic opportunities for more effective management of hypertension in high-risk patients with advanced CKD.
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    Short-duration splice promoting compound enables a tunable mouse model of spinal muscular atrophy
    (EMBO Press, 2021-01) Rietz, Anne; Hodgetts, Kevin J.; Lusic, Hrvoje; Quist, Kevin M.; Osman, Erkan Y.; Lorson, Christian L.; Androphy, Elliot J.; Dermatology, School of Medicine
    Spinal muscular atrophy (SMA) is a motor neuron disease and the leading genetic cause of infant mortality. SMA results from insufficient survival motor neuron (SMN) protein due to alternative splicing. Antisense oligonucleotides, gene therapy and splicing modifiers recently received FDA approval. Although severe SMA transgenic mouse models have been beneficial for testing therapeutic efficacy, models mimicking milder cases that manifest post-infancy have proven challenging to develop. We established a titratable model of mild and moderate SMA using the splicing compound NVS-SM2. Administration for 30 d prevented development of the SMA phenotype in severe SMA mice, which typically show rapid weakness and succumb by postnatal day 11. Furthermore, administration at day eight resulted in phenotypic recovery. Remarkably, acute dosing limited to the first 3 d of life significantly enhanced survival in two severe SMA mice models, easing the burden on neonates and demonstrating the compound as suitable for evaluation of follow-on therapies without potential drug-drug interactions. This pharmacologically tunable SMA model represents a useful tool to investigate cellular and molecular pathogenesis at different stages of disease.
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    The Association Between the Occurrence of Common Treatment-Emergent Adverse Events and Efficacy Outcomes After Lasmiditan Treatment of a Single Migraine Attack: Secondary Analyses from Four Pooled Randomized Clinical Trial
    (Springer, 2022) Doty, Erin G.; Hauck, Paula M.; Krege, John H.; Komori, Mika; Hake, Ann M.; Dong, Yan; Lipton, Richard B.; Neurology, School of Medicine
    Background: In controlled clinical trials, compared with placebo, a significantly greater proportion of participants using lasmiditan to treat a migraine attack achieved 2-h pain freedom (PF) and experienced ≥ 1 treatment-emergent adverse event (TEAE). Objective: To better inform clinicians about treatment expectations by evaluating the association between TEAEs and efficacy outcomes after lasmiditan treatment. Methods: Pooled data from SAMURAI, SPARTAN, MONONOFU, and CENTURION were analyzed. A common TEAE (CTEAE) was defined as occurring in ≥ 2% in the overall population. Central nervous system (CNS)-CTEAEs were based on Medical Dictionary for Regulatory Activities. Results: At 2 h, a significantly higher percentage of lasmiditan 200 mg-treated participants who achieved PF experienced ≥ 1 CTEAE than non-responders who continued to experience moderate/severe pain (48.2% vs. 28.7%, respectively). Correspondingly, a significantly higher percentage of lasmiditan 200 mg-treated participants who experienced ≥ 1 CTEAE achieved PF at 2 h than those who did not (39.0% vs. 30.2%, respectively). Similar results were generally observed with individual CNS-CTEAEs, but for non-CNS-CTEAEs, this pattern was less evident or in the opposite direction. No consistent differences were observed for migraine-related functional disability freedom. The percentage of participants with improved patient global impression of change (PGIC) was greater with a CNS-CTEAE versus no CNS-CTEAE. Conclusions: Those who had PF at 2 h were more likely to experience a CNS-CTEAE, and those with CNS-CTEAEs were more likely to experience PF. The occurrence of CTEAEs did not seem to negatively affect disability freedom or PGIC.