Publications by authors named "Ryan Choi"

Article Synopsis
  • Drug development for congenital toxoplasmosis is challenging due to high adverse effects and poor efficacy of first-line therapies; bumped kinase inhibitors (BKIs) like BKI-1748 may offer a new treatment option.
  • In a study involving 19 pregnant sheep, those treated with BKI-1748 after infection showed lower fever and immunological responses compared to untreated counterparts.
  • The treated group had a higher percentage of healthy lambs at delivery and showed no evidence of congenital transmission of the parasite, unlike the untreated group where parasite DNA was detectable.
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Griselimycin, a cyclic depsidecapeptide produced by Streptomyces griseus, is a promising lead inhibitor of the sliding clamp component of bacterial DNA polymerases (β-subunit of Escherichia coli DNA pol III). It was previously shown to inhibit the Mycobacterium tuberculosis β-clamp with remarkably high affinity and selectivity - the peptide lacks any interaction with the human sliding clamp. Here, we used a structural genomics approach to address the prospect of broader-spectrum inhibition, in particular of β-clamps from Gram-negative bacterial targets.

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  • - Atherosclerosis is an inflammatory disease leading to heart issues, and enhancing the process of efferocytosis (cell removal by macrophages) is being explored as a potential treatment.
  • - Blocking CD47, which signals cells not to be engulfed, reduces plaque buildup but can also cause anemia due to red blood cell clearance.
  • - A new macrophage-specific nanotherapy was developed to promote efferocytosis without causing anemia, proving effective in early atherosclerosis models in pigs, showing promise for future treatments.
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A phospholamban mutation is a rare genetic cause of dilated cardiomyopathy (DCM). Our case describes a young service member who presented with advanced heart failure and was found to have a familial DCM from an autosomal dominant phospholamban mutation. He ultimately underwent a successful heart transplant just 23 days after his initial presentation.

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Article Synopsis
  • Toxoplasma gondii and Neospora caninum are significant pathogens causing health issues globally, and Bumped Kinase Inhibitors (BKIs) represent a promising class of drugs targeted at combating these infections.
  • BKI-1708, a specific BKI, has shown strong in vitro potency against these pathogens while maintaining high safety for human cells, indicated by its minimal effect on human foreskin fibroblast viability.
  • In animal studies, BKI-1708 demonstrated an ability to reduce parasite loads in pregnant mice without affecting their pregnancy outcomes, highlighting its potential as a treatment for these infections.
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Article Synopsis
  • Researchers have identified calcium-dependent protein kinase 1 (CDPK1) in the protozoan responsible for cryptosporidiosis as a promising target for new therapies.
  • A specific compound, a pyridopyrimidinone, was found to effectively inhibit CdPK1 and prevent the growth of various strains of the parasite in host cells.
  • Although the compound showed low systemic exposure after oral dosing, it achieved high concentrations in the gastrointestinal tract and demonstrated some effectiveness in animal models of the disease.
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  • - The study investigates the association between genetic variations on the X chromosome and sporadic thoracic aortic aneurysm and dissection (TAD) in male patients, based on three European descent cohorts.
  • - For common variants, no significant results were found in the initial Discovery cohort, but a variant near SPANXN1 showed significance in the Replication cohort, with ZNF182 emerging as a notable candidate in the combined analysis.
  • - Although many findings were statistically insignificant, this research represents the most thorough examination of X-linked variations related to sporadic TAD thus far.
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  • Metastatic castration-resistant prostate cancer is still incurable, despite recent treatments, and tumors show increased glycolysis as they progress.
  • The study introduces BKIDC-1553, a new small-molecule compound that inhibits glycolysis specifically in prostate cancer cells without causing severe toxicity, and demonstrates promising results in preclinical models.
  • BKIDC-1553 shows effective growth inhibition in various prostate cancer models and has safety and pharmacokinetic properties that suggest it’s ready for clinical trials to treat advanced prostate cancer.
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Thiamin and its phosphate derivatives are ubiquitous molecules involved as essential cofactors in many cellular processes. The biosynthesis of thiamin employs the parallel synthesis of 4-methyl-5-(2-hydroxyethyl)thiazole (THZ-P) and 4-amino-2-methyl-5(diphosphooxymethyl) pyrimidine (HMP) pyrophosphate (HMP-PP), which are coupled to generate thiamin phosphate. Most organisms that can biosynthesize thiamin employ a kinase (HMPK or ThiD) to generate HMP-PP.

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Article Synopsis
  • Congenital toxoplasmosis is a significant issue in both humans and animals, causing abortion and fetal abnormalities.
  • The CDPK1 inhibitor BKI-1748 demonstrated safety in humans and effectiveness against Toxoplasma gondii in lab studies and mouse models.
  • In sheep infected during pregnancy, BKI-1748 treatment began 48 hours post-infection successfully prevented abortion and congenital infection, with treated sheep showing minimal symptoms compared to untreated ones.
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SARS-CoV-2, the etiologic agent of the COVID-19 pandemic, has had an enduring impact on global public health. However, SARS-CoV-2 is only one of multiple pathogenic human coronaviruses (CoVs) to have emerged since the turn of the century. CoVs encode for several nonstructural proteins (nsps) that are essential for viral replication and pathogenesis.

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Whipple's Disease (WD) is a rare disease caused by the infection of Tropheryma whipplei. It can lead to immunosuppression and a multitude of effects on different organ systems, resulting in a constellation of seemingly unrelated findings. Although treatment may appear straightforward, T.

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Article Synopsis
  • Metastatic castration-resistant prostate cancer remains largely untreatable, but this study focuses on a new small molecule, BKIDC-1553, that inhibits glycolysis in cancer cells without significant toxicity.
  • Researchers tested BKIDC-1553 across various prostate cancer models and found it effectively inhibits cell proliferation and shows promising results in preclinical trials, comparable to existing treatments like enzalutamide.
  • The findings suggest that BKIDC-1553 has the potential for safe use in human clinical trials, paving the way for new treatment options for advanced prostate cancer patients.
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  • There's a significant need for effective treatments for giardiasis, a disease caused by the parasite Giardia lamblia, especially since many current drugs are becoming ineffective due to resistance.
  • This study screened natural products and fungal extracts, discovering new classes of compounds that inhibit G. lamblia growth, suggesting potential alternative therapies.
  • The findings advocate for developing inexpensive, nature-derived drugs to address giardiasis, particularly in impoverished communities where it causes severe health issues in children.
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Recent advances on the development of bumped kinase inhibitors for treatment of cryptosporidiosis have focused on the 5-aminopyrazole-4-carboxamide scaffold, due to analogs that have less hERG inhibition, superior efficacy, and strong safety profiles. Three compounds, BKI-1770, -1841, and -1708, showed strong efficacy in C. parvum infected mice.

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  • Researchers combined computational design and experimental testing to explore how to improve membrane permeability and oral bioavailability in macrocycles.
  • They designed 184 macrocycles and confirmed the structures of 35, finding that many closely match their predictions and establishing that specific hydrogen bonding in the molecular structure is key to enhancing permeability.
  • Their findings suggest that by carefully manipulating hydrogen bonding interactions, they can develop peptides that efficiently cross membranes and could lead to more effective therapeutic options in the future.
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This paper analyzes an incentive contract for new vaccine research and development (R&D) under pandemic situations such as COVID-19, considering the R&D contract's adaptability to the pandemic. We study how the public sector (government) designs the adaptive R&D contract and offers it to pharmaceutical enterprises. An agency-theoretic model is employed to explore the contract whose terms are an upfront grant as a fixed fee and a sales tax credit as an incentive tool, examining how the values of related parameters affect contract term determinations.

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Article Synopsis
  • - A phenotypic screen of the ReFRAME compound library pinpointed 85 cell-active compounds for treating giardiasis, yielding a hit rate of 0.72% from Giardia lamblia, GS clone H7.
  • - Mavelertinib, a third-generation EGFR tyrosine kinase inhibitor, was identified as a promising therapeutic agent due to its effectiveness against metronidazole-resistant strains and a unique binding mechanism distinct from traditional EGFR-TKIs.
  • - In murine infection models, mavelertinib showed significant efficacy at doses ranging from 5 to 50 mg/kg, prompting consideration for its repurposing in giardiasis clinical trials while further development of its analogues continues.
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  • - Understanding how biogeochemical cycles of carbon, nitrogen, and phosphorus interact is crucial, especially as human activities impact climate and these cycles, particularly in dryland ecosystems which cover over 40% of Earth's land surface.
  • - Research on the Colorado Plateau tested how water, carbon, nitrogen, and phosphorus influence soil carbon cycling. Results indicated that water, carbon, and nitrogen collectively support carbon cycling, with water being a key factor in generating a significant response when combined with carbon.
  • - The study revealed that nitrogen alone doesn't affect soil carbon cycling but enhances carbon cycling rates when combined with water and carbon, while phosphorus showed no impact. These findings highlight the complex interplay of resource limitations in dryland ecosystems.
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The Neospora caninum Calcium-dependent protein kinase 1 (NcCDPK1) inhibitor BKI-1294 had demonstrated excellent efficacy in a pregnant mouse model of neosporosis, and was also highly efficacious in a pregnant sheep model of toxoplasmosis. In this work, we present the efficacy of BKI-1294 treatment (dosed 5 times orally every 48 h) starting 48 h after intravenous infection of sheep with 10 Nc-Spain7 tachyzoites at mid-pregnancy. In the dams, BKI-1294 plasma concentrations were above the IC for N.

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The apicomplexan parasite Neospora caninum is an important causative agent of congenital neosporosis, resulting in abortion, birth of weak offspring and neuromuscular disorders in cattle, sheep, and many other species. Among several compound classes that are currently being developed, two have been reported to limit the effects of congenital neosporosis: (i) bumped kinase inhibitors (BKIs) target calcium dependent protein kinase 1 (CDPK1), an enzyme that is encoded by an apicoplast-derived gene and found only in apicomplexans and plants. CDPK1 is essential for host cell invasion and egress; (ii) endochin-like quinolones (ELQs) are inhibitors of the cytochrome bc complex of the mitochondrial electron transport chain and thus inhibit oxidative phosphorylation.

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Article Synopsis
  • - Bumped kinase inhibitors (BKIs), specifically BKI-1748, effectively inhibit the growth of apicomplexan parasites like Neospora caninum and Toxoplasma gondii, showing significant activity at low concentrations (ECs of 165 nM and 43 nM, respectively) when tested on fibroblast cells.
  • - Treatment with BKI-1748 led to the formation of multinucleated schizont-like complexes in infected cells, preventing the parasites from becoming infectious and egressing, and displayed no detrimental effects on zebrafish embryos or pregnant mice.
  • - In mouse models, BKI-1748 improved pup survival and reduced the transmission of N. caninum and T. gond
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SARS-CoV-2 has caused a global pandemic, and has taken over 1.7 million lives as of mid-December, 2020. Although great progress has been made in the development of effective countermeasures, with several pharmaceutical companies approved or poised to deliver vaccines to market, there is still an unmet need of essential antiviral drugs with therapeutic impact for the treatment of moderate-to-severe COVID-19.

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Article Synopsis
  • New drugs are urgently needed to treat infections in malnourished children under 2 and individuals with weakened immune systems in developing countries.
  • Researchers screened bioactive compounds from the Tres-Cantos GSK library, identifying 19 compounds and narrowing them down to four clusters for further testing in a mouse infection model.
  • Only one compound, an imidazole-pyrimidine, showed significant effectiveness in clearing the infection, demonstrating good safety and activity at low doses, and it targets calcium-dependent protein kinase 1, suggesting potential for future therapeutic development.
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Article Synopsis
  • * The new compound BKI-1649, featuring a unique pyrrolopyrimidine scaffold, has demonstrated better effectiveness in mouse models at lower doses than earlier pyrazolopyrimidine variants.
  • * Two derivatives, BKI-1812 and BKI-1814, were tested and showed enhanced potency compared to previous BKIs, while maintaining similar levels of toxicity and efficacy as their pyrazolopyrimidine counterparts.
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