Publications by authors named "Kasey L Rivas"

Cryptosporidium is a leading cause of pediatric diarrhea worldwide. Currently, there is neither a vaccine nor a consistently effective drug available for this disease. Selective 5-aminopyrazole-4-carboxamide-based bumped-kinase inhibitors (BKIs) are effective in both in vitro and in vivo models of Cryptosporidium parvum.

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Article Synopsis
  • Bumped kinase inhibitors (BKIs) effectively inhibit Toxoplasma gondii calcium-dependent protein kinase 1, showing potential in treating toxoplasmosis.
  • Pyrazolopyrimidine and 5-aminopyrazole-4-carboxamide scaffolds have been tested in both acute and chronic models, with recent discoveries of new scaffolds like pyrrolopyrimidine enhancing potency against acute toxoplasmosis.
  • Structural modifications in the BKIs lead to varying plasma concentrations while ensuring low toxicity in human cell assays and mice, marking them as promising candidates for advanced anti-Toxoplasma therapies.
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Neospora caninum is one of the main causes of abortion in cattle, and recent studies have highlighted its relevance as an abortifacient in small ruminants. Vaccines or drugs for the control of neosporosis are lacking. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models.

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Improvements have been made to the safety and efficacy of bumped kinase inhibitors, and they are advancing toward human and animal use for treatment of cryptosporidiosis. As the understanding of bumped kinase inhibitor pharmacodynamics for cryptosporidiosis therapy has increased, it has become clear that better compounds for efficacy do not necessarily require substantial systemic exposure. We now have a bumped kinase inhibitor with reduced systemic exposure, acceptable safety parameters, and efficacy in both the mouse and newborn calf models of cryptosporidiosis.

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Bumped kinase inhibitors (BKIs) of Cryptosporidium parvum calcium-dependent protein kinase 1 (CpCDPK1) are leading candidates for treatment of cryptosporidiosis-associated diarrhea. Potential cardiotoxicity related to anti-human ether-à-go-go potassium channel (hERG) activity of the first-generation anti-Cryptosporidium BKIs triggered further testing for efficacy. A luminescence assay adapted for high-throughput screening was used to measure inhibitory activities of BKIs against C.

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Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, is a diarrheal disease that has produced a large global burden in mortality and morbidity in humans and livestock. There are currently no consistently effective parasite-specific pharmaceuticals available for this disease. Bumped kinase inhibitors (BKIs) specific for parasite calcium-dependent protein kinases (CDPKs) have been shown to reduce infection in several parasites having medical and veterinary importance, including Toxoplasma gondii, Plasmodium falciparum, and C.

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Article Synopsis
  • Researchers identified prolyl-tRNA synthetase (ProRS) in the malaria-causing parasite Plasmodium falciparum (Pf) as a promising drug target, but selective inhibitors for this target were previously unreported.
  • By screening around 40,000 compounds, the study discovered two new allosteric inhibitors that specifically target PfProRS with over 100 times more selectivity than the human version (HsProRS).
  • The findings, supported by X-ray crystallography, pave the way for further medicinal chemistry efforts to optimize these inhibitors for potential malaria treatments without the toxicity associated with existing drugs.
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Sarcocystis neurona is the most frequent cause of equine protozoal myeloencephalitis, a debilitating neurological disease of horses that can be difficult to treat. We identified SnCDPK1, the S. neurona homologue of calcium-dependent protein kinase 1 (CDPK1), a validated drug target in Toxoplasma gondii.

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Article Synopsis
  • New therapies are needed for toxoplasmosis caused by the Toxoplasma gondii parasite, necessitating the development of effective treatments.
  • Earlier developed compound 1 showed strong anti-Toxoplasma activity but posed a risk of cardiotoxicity due to its harmful effects on the hERG gene.
  • The newly identified optimized inhibitor 32 has no hERG liability, shows good pharmacokinetics in animals, and effectively reduces T. gondii infection in mouse models, making it a strong candidate for a new treatment.
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In 2010 the identities of thousands of anti-Plasmodium compounds were released publicly to facilitate malaria drug development. Understanding these compounds' mechanisms of action--i.e.

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Article Synopsis
  • Malaria is spread by mosquitoes, and blocking its transmission is essential for reducing infection rates, particularly in areas where it is common.
  • Researchers discovered a new class of compounds that inhibit a specific enzyme (CDPK4) in the malaria parasite, which is crucial for transmission, while sparing human kinases.
  • They demonstrated that these compounds effectively targeted the CDPK4 enzyme in genetically modified P. falciparum parasites and proposed combining these agents with existing antimalarials like artemisinin to better combat malaria transmission, including resistant strains.
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An established paradigm in current drug development is (i) to identify a single protein target whose inhibition is likely to result in the successful treatment of a disease of interest; (ii) to assay experimentally large libraries of small-molecule compounds in vitro and in vivo to identify promising inhibitors in model systems; and (iii) to determine whether the findings are extensible to humans. This complex process, which is largely based on trial and error, is risk-, time- and cost-intensive. Computational (virtual) screening of drug-like compounds simultaneously against the atomic structures of multiple protein targets, taking into account protein-inhibitor dynamics, might help to identify lead inhibitors more efficiently, particularly for complex drug-resistant diseases.

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New antimalarials are urgently needed. We have shown that tetrahydroquinoline (THQ) protein farnesyltransferase (PFT) inhibitors (PFTIs) are effective against the Plasmodium falciparum PFT and are effective at killing P. falciparum in vitro.

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