RESUMEN
Hepatopancreatic microsporidiosis (HPM), caused by the microsporidium Ecytonucleospora hepatopenaei (EHP) leads to retarded growth and enhanced susceptibility to other diseases in shrimp resulting in a major loss for the shrimp industry worldwide. It is little understood how EHP infects its host and hijacks its cellular machinery to replicate and exert clinical manifestations in infected shrimp. Since the initial record of HPM, histopathology and polymerase chain reaction (PCR)-based assays were developed for the detection of EHP to prevent spread of the disease. Availability of an antibody-based detection method would complement these existing diagnostic tools and be useful in studying EHP pathogenesis. We describe here an immunofluorescence assay (IFA) for detecting EHP using monoclonal antibodies (mAbs) that were originally developed against Cryptosporidium parvum, a coccidian parasite that infects calves (Bos taurus), other agriculturally important animals, and humans. Forty-one mAbs were screened and two mAbs, 3E2 and 3A12, were found to detect EHP successfully. The utility of these mAbs in detecting EHP was further assessed by testing 36 experimentally challenged EHP-infected shrimp (Penaeus vannamei). EHP-detection data from infected shrimp were compared by Hematoxylin and Eosin (H&E) histology, real-time PCR, and immunofluorescence. The data show IFA using mAbs 3E2 and 3A12 could successfully detect EHP and that the sensitivity of detection is comparable to H&E histology and quantitative PCR. Availability of mAbs that can detect EHP is expected to be immensely beneficial in HPM diagnosis. Since the pathobiology of C. parvum has been so widely studied, these cross-reactive mAbs may also aid in gaining some insight into EHP pathogenesis and disease.
RESUMEN
Recent advances in the in vitro cultivation of Cryptosporidium parvum using hollow fiber bioreactor technology (HFB) have permitted continuous growth of parasites that complete all life cycle stages. The method provides access to all stages of the parasite and provides a method for non-animal production of oocysts for use in clinical trials. Here we examined the effect of long-term (>20 months) in vitro culture on virulence-factors, genome conservation, and in vivo pathogenicity of the host by in vitro cultured parasites. We find low-level sequence variation that is consistent with that observed in calf-passaged parasites. Further using a calf model infection, oocysts obtained from the HFB caused diarrhea of the same volume, duration and oocyst shedding intensity as in vivo passaged parasites.
Asunto(s)
Criptosporidiosis , Cryptosporidium parvum , Cryptosporidium , Animales , Cryptosporidium parvum/genética , Virulencia , Criptosporidiosis/parasitología , Oocistos , Genómica , HecesRESUMEN
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 in vitro safety profiles. Three compounds, BKI-1770, -1841, and -1708, showed strong efficacy in C. parvum infected mice. Both BKI-1770 and BKI-1841 had efficacy in the C. parvum newborn calf model, reducing diarrhea and oocyst excretion. However, both compounds caused hyperflexion of the limbs seen as dropped pasterns. Toxicity experiments in rats and calves dosed with BKI-1770 showed enlargement of the epiphyseal growth plate at doses only slightly higher than the efficacious dose. Mice were used as a screen to check for bone toxicity, by changes to the tibia epiphyseal growth plate, or neurological causes, by use of a locomotor activity box. These results showed neurological effects from both BKI-1770 and BKI-1841 and bone toxicity in mice from BKI-1770, indicating one or both effects may be contributing to toxicity. However, BKI-1708 remains a viable treatment candidate for further evaluation as it showed no signs of bone toxicity or neurological effects in mice.
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Antineoplásicos , Antiprotozoarios , Criptosporidiosis , Cryptosporidium parvum , Animales , Bovinos , Ratones , Ratas , Criptosporidiosis/tratamiento farmacológico , Antiprotozoarios/farmacología , Antineoplásicos/farmacología , Inhibidores de Proteínas Quinasas/farmacología , OocistosRESUMEN
Infection with Cryptosporidium spp. can cause severe diarrhea, leading to long-term adverse impacts and even death in malnourished children and immunocompromised patients. The only FDA-approved drug for treating cryptosporidiosis, nitazoxanide, has limited efficacy in the populations impacted the most by the diarrheal disease, and safe, effective treatment options are urgently needed. Initially identified by a large-scale phenotypic screening campaign, the antimycobacterial therapeutic clofazimine demonstrated great promise in both in vitro and in vivo preclinical models of Cryptosporidium infection. Unfortunately, a phase 2a clinical trial in HIV-infected adults with cryptosporidiosis did not identify any clofazimine treatment effect on Cryptosporidium infection burden or clinical outcomes. To explore whether clofazimine's lack of efficacy in the phase 2a trial may have been due to subtherapeutic clofazimine concentrations, a pharmacokinetic/pharmacodynamic modeling approach was undertaken to determine the relationship between clofazimine in vivo concentrations and treatment effects in multiple preclinical infection models. Exposure-response relationships were characterized using Emax and logistic models, which allowed predictions of efficacious clofazimine concentrations for the control and reduction of disease burden. After establishing exposure-response relationships for clofazimine treatment of Cryptosporidium infection in our preclinical model studies, it was unmistakable that the clofazimine levels observed in the phase 2a study participants were well below concentrations associated with anti-Cryptosporidium efficacy. Thus, despite a dosing regimen above the highest doses recommended for mycobacterial therapy, it is very likely the lack of treatment effect in the phase 2a trial was at least partially due to clofazimine concentrations below those required for efficacy against cryptosporidiosis. It is unlikely that clofazimine will provide a remedy for the large number of cryptosporidiosis patients currently without a viable treatment option unless alternative, safe clofazimine formulations with improved oral absorption are developed. (This study has been registered in ClinicalTrials.gov under identifier NCT03341767.).
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Antiprotozoarios , Criptosporidiosis , Cryptosporidium , Adulto , Antiprotozoarios/farmacología , Antiprotozoarios/uso terapéutico , Niño , Clofazimina/farmacología , Clofazimina/uso terapéutico , Criptosporidiosis/tratamiento farmacológico , Diarrea/tratamiento farmacológico , HumanosRESUMEN
This is a review of the development of bumped-kinase inhibitors (BKIs) for the therapy of One Health parasitic apicomplexan diseases. Many apicomplexan infections are shared between humans and livestock, such as cryptosporidiosis and toxoplasmosis, as well as livestock only diseases such as neosporosis. We have demonstrated proof-of-concept for BKI therapy in livestock models of cryptosporidiosis (newborn calves infected with Cryptosporidium parvum), toxoplasmosis (pregnant sheep infected with Toxoplasma gondii), and neosporosis (pregnant sheep infected with Neospora caninum). We discuss the potential uses of BKIs for the treatment of diseases caused by apicomplexan parasites in animals and humans, and the improvements that need to be made to further develop BKIs.
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Antiparasitarios/farmacología , Criptosporidiosis/tratamiento farmacológico , Salud Única , Piperidinas/farmacología , Pirimidinas/farmacología , Quinolinas/farmacología , Animales , Apicomplexa , HumanosRESUMEN
The protozoan parasite Cryptosporidium sp. is a leading cause of diarrheal disease in those with compromised or underdeveloped immune systems, particularly infants and toddlers in resource-poor localities. As an enteric pathogen, Cryptosporidium sp. invades the apical surface of intestinal epithelial cells, where it resides in close proximity to metabolites in the intestinal lumen. However, the effect of gut metabolites on susceptibility to Cryptosporidium infection remains largely unstudied. Here, we first identified which gut metabolites are prevalent in neonatal mice when they are most susceptible to Cryptosporidium parvum infection and then tested the isolated effects of these metabolites on C. parvum invasion and growth in intestinal epithelial cells. Our findings demonstrate that medium or long-chain saturated fatty acids inhibit C. parvum growth, perhaps by negatively affecting the streamlined metabolism in C. parvum, which is unable to synthesize fatty acids. Conversely, long-chain unsaturated fatty acids enhanced C. parvum invasion, possibly by modulating membrane fluidity. Hence, gut metabolites, either from diet or produced by the microbiota, influence C. parvum growth in vitro and may also contribute to the early susceptibility to cryptosporidiosis seen in young animals.IMPORTANCECryptosporidium sp. occupies a unique intracellular niche that exposes the parasite to both host cell contents and the intestinal lumen, including metabolites from the diet and produced by the microbiota. Both dietary and microbial products change over the course of early development and could contribute to the changes seen in susceptibility to cryptosporidiosis in humans and mice. Consistent with this model, we show that the immature gut metabolome influenced the growth of Cryptosporidium parvumin vitro Interestingly, metabolites that significantly altered parasite growth were fatty acids, a class of molecules that Cryptosporidium sp. is unable to synthesize de novo The enhancing effects of polyunsaturated fatty acids and the inhibitory effects of saturated fatty acids presented in this study may provide a framework for future studies into this enteric parasite's interactions with exogenous fatty acids during the initial stages of infection.
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Bacterias/metabolismo , Criptosporidiosis/parasitología , Cryptosporidium parvum/fisiología , Microbioma Gastrointestinal , Mucosa Intestinal/microbiología , Mucosa Intestinal/parasitología , Animales , Animales Recién Nacidos/metabolismo , Animales Recién Nacidos/microbiología , Animales Recién Nacidos/parasitología , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Criptosporidiosis/metabolismo , Criptosporidiosis/microbiología , Cryptosporidium parvum/genética , Modelos Animales de Enfermedad , Células Epiteliales/metabolismo , Células Epiteliales/microbiología , Células Epiteliales/parasitología , Ácidos Grasos/metabolismo , Femenino , Humanos , Mucosa Intestinal/metabolismo , Masculino , Ratones , Ratones Endogámicos ICRRESUMEN
Apicomplexan parasites cause severe disease in both humans and their domesticated animals. Since these parasites readily develop drug resistance, development of new, effective drugs to treat infection caused by these parasites is an ongoing challenge for the medical and veterinary communities. We hypothesized that invertebrate-bacterial symbioses might be a rich source of anti-apicomplexan compounds because invertebrates are susceptible to infections with gregarines, parasites that are ancestral to all apicomplexans. We chose to explore the therapeutic potential of shipworm symbiotic bacteria as they are bona fide symbionts, are easily grown in axenic culture and have genomes rich in secondary metabolite loci [1,2]. Two strains of the shipworm symbiotic bacterium, Teredinibacter turnerae, were screened for activity against Toxoplasma gondii and one strain, T7901, exhibited activity against intracellular stages of the parasite. Bioassay-guided fractionation identified tartrolon E (trtE) as the source of the activity. TrtE has an EC50 of 3 nM against T. gondii, acts directly on the parasite itself and kills the parasites after two hours of treatment. TrtE exhibits nanomolar to picomolar level activity against Cryptosporidium, Plasmodium, Babesia, Theileria, and Sarcocystis; parasites representing all branches of the apicomplexan phylogenetic tree. The compound also proved effective against Cryptosporidium parvum infection in neonatal mice, indicating that trtE may be a potential lead compound for preclinical development. Identification of a promising new compound after such limited screening strongly encourages further mining of invertebrate symbionts for new anti-parasitic therapeutics.
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Antiprotozoarios , Apicomplexa/crecimiento & desarrollo , Bivalvos/microbiología , Gammaproteobacteria/metabolismo , Simbiosis , Animales , Antiprotozoarios/metabolismo , Antiprotozoarios/farmacología , Ratones , Infecciones por Protozoos/tratamiento farmacológicoRESUMEN
Copy number alterations (CNAs) play an important role in molding the genomes of breast cancers and have been shown to be clinically useful for prognostic and therapeutic purposes. However, our knowledge of intra-tumoral genetic heterogeneity of this important class of somatic alterations is limited. Here, using single-cell sequencing, we comprehensively map out the facets of copy number alteration heterogeneity in a cohort of breast cancer tumors. Ou/var/www/html/elife/12-05-2020/backup/r analyses reveal: genetic heterogeneity of non-tumor cells (i.e. stroma) within the tumor mass; the extent to which copy number heterogeneity impacts breast cancer genomes and the importance of both the genomic location and dosage of sub-clonal events; the pervasive nature of genetic heterogeneity of chromosomal amplifications; and the association of copy number heterogeneity with clinical and biological parameters such as polyploidy and estrogen receptor negative status. Our data highlight the power of single-cell genomics in dissecting, in its many forms, intra-tumoral genetic heterogeneity of CNAs, the magnitude with which CNA heterogeneity affects the genomes of breast cancers, and the potential importance of CNA heterogeneity in phenomena such as therapeutic resistance and disease relapse.
Cells in the body remain healthy by tightly preventing and repairing random changes, or mutations, in their genetic material. In cancer cells, however, these mechanisms can break down. When these cells grow and multiply, they can then go on to accumulate many mutations. As a result, cancer cells in the same tumor can each contain a unique combination of genetic changes. This genetic heterogeneity has the potential to affect how cancer responds to treatment, and is increasingly becoming appreciated clinically. For example, if a drug only works against cancer cells carrying a specific mutation, any cells lacking this genetic change will keep growing and cause a relapse. However, it is still difficult to quantify and understand genetic heterogeneity in cancer. Copy number alterations (or CNAs) are a class of mutation where large and small sections of genetic material are gained or lost. This can result in cells that have an abnormal number of copies of the genes in these sections. Here, Baslan et al. set out to explore how CNAs might vary between individual cancer cells within the same tumor. To do so, thousands of individual cancer cells were isolated from human breast tumors, and a technique called single-cell genome sequencing used to screen the genetic information of each of them. These experiments confirmed that CNAs did differ sometimes dramatically between patients and among cells taken from the same tumor. For example, many of the cells carried extra copies of well-known cancer genes important for treatment, but the exact number of copies varied between cells. This heterogeneity existed for individual genes as well as larger stretches of DNA: this was the case, for instance, for an entire section of chromosome 8, a region often affected in breast and other tumors. The work by Baslan et al. captures the sheer extent of genetic heterogeneity in cancer and in doing so, highlights the power of single-cell genome sequencing. In the future, a finer understanding of the genetic changes present at the level of an individual cancer cell may help clinicians to manage the disease more effectively.
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Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Variaciones en el Número de Copia de ADN , Dosificación de Gen , Heterogeneidad Genética , Genómica , Análisis de la Célula Individual , Secuenciación Completa del Genoma , Neoplasias de la Mama/mortalidad , Neoplasias de la Mama/patología , Neoplasias de la Mama/terapia , Ensayos Clínicos Fase II como Asunto , Femenino , Predisposición Genética a la Enfermedad , Humanos , Fenotipo , Pronóstico , RNA-SeqRESUMEN
Bumped Kinase Inhibitors, targeting Calcium-dependent Protein Kinase 1 in apicomplexan parasites with a glycine gatekeeper, are promising new therapeutics for apicomplexan diseases. Here we will review advances, as well as challenges and lessons learned regarding efficacy, safety, and pharmacology that have shaped our selection of pre-clinical candidates.
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Apicomplexa/efectos de los fármacos , Coccidiosis/tratamiento farmacológico , Inhibidores de Proteínas Quinasas , Animales , Apicomplexa/metabolismo , Criptosporidiosis/tratamiento farmacológico , Cryptosporidium/efectos de los fármacos , Cryptosporidium/metabolismo , Humanos , Inhibidores de Proteínas Quinasas/efectos adversos , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/efectos de los fármacos , Proteínas Quinasas/metabolismo , Toxoplasma/efectos de los fármacos , Toxoplasma/metabolismo , Toxoplasmosis/tratamiento farmacológicoRESUMEN
Cryptosporidiosis, caused by the apicomplexan parasite Cryptosporidium parvum, is a moderate-to-severe diarrheal disease now recognized as one of the leading causes of morbidity and mortality in livestock globally, and in humans living in resource-limited parts of the world, particularly those with AIDS or malnourished individuals. This recognition has fueled efforts for the discovery of effective therapeutics. While recent progress in drug discovery has been encouraging, there are presently no acceptably effective parasite-specific drugs for the disease. The urgent need for new drug discovery or drug repurposing has also increased the need for refined animal models of clinical disease for therapeutic efficacy evaluation. Here, we describe an acute model of cryptosporidiosis using newborn calves to evaluate well-defined clinical and parasitological parameter outcomes, including the effect on diarrhea severity and duration, oocyst numbers produced, and multiple measures of clinical health. The model is highly reproducible and provides unequivocal direct measures of treatment efficacy on diarrhea severity and parasite replication.
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Enfermedades de los Bovinos/tratamiento farmacológico , Criptosporidiosis/tratamiento farmacológico , Cryptosporidium parvum/efectos de los fármacos , Diarrea/veterinaria , Modelos Animales de Enfermedad , Oocistos/efectos de los fármacos , Animales , Bovinos , Enfermedades de los Bovinos/parasitología , Enfermedades de los Bovinos/patología , Enfermedades de los Bovinos/orina , Criptosporidiosis/parasitología , Criptosporidiosis/patología , Criptosporidiosis/orina , Cryptosporidium parvum/crecimiento & desarrollo , Cryptosporidium parvum/parasitología , Diarrea/tratamiento farmacológico , Diarrea/parasitología , Diarrea/patología , Heces/parasitología , Humanos , Recién Nacido , Oocistos/crecimiento & desarrollo , Oocistos/aislamiento & purificación , Oocistos/metabolismo , Flujo de TrabajoRESUMEN
Stem-cell-derived organoids recapitulate in vivo physiology of their original tissues, representing valuable systems to model medical disorders such as infectious diseases. Cryptosporidium, a protozoan parasite, is a leading cause of diarrhoea and a major cause of child mortality worldwide. Drug development requires detailed knowledge of the pathophysiology of Cryptosporidium, but experimental approaches have been hindered by the lack of an optimal in vitro culture system. Here, we show that Cryptosporidium can infect epithelial organoids derived from human small intestine and lung. The parasite propagates within the organoids and completes its complex life cycle. Temporal analysis of the Cryptosporidium transcriptome during organoid infection reveals dynamic regulation of transcripts related to its life cycle. Our study presents organoids as a physiologically relevant in vitro model system to study Cryptosporidium infection.
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Criptosporidiosis/genética , Cryptosporidium/patogenicidad , Perfilación de la Expresión Génica/métodos , Organoides/parasitología , Criptosporidiosis/parasitología , Cryptosporidium/crecimiento & desarrollo , Regulación de la Expresión Génica , Humanos , Intestino Delgado/parasitología , Pulmón/parasitología , Modelos Biológicos , Técnicas de Cultivo de Órganos , Análisis de Secuencia de ARN , Análisis Espacio-TemporalRESUMEN
A distinction between indolent and aggressive disease is a major challenge in diagnostics of prostate cancer. As genetic heterogeneity and complexity may influence clinical outcome, we have initiated studies on single tumor cell genomics. In this study, we demonstrate that sparse DNA sequencing of single-cell nuclei from prostate core biopsies is a rich source of quantitative parameters for evaluating neoplastic growth and aggressiveness. These include the presence of clonal populations, the phylogenetic structure of those populations, the degree of the complexity of copy-number changes in those populations, and measures of the proportion of cells with clonal copy-number signatures. The parameters all showed good correlation to the measure of prostatic malignancy, the Gleason score, derived from individual prostate biopsy tissue cores. Remarkably, a more accurate histopathologic measure of malignancy, the surgical Gleason score, agrees better with these genomic parameters of diagnostic biopsy than it does with the diagnostic Gleason score and related measures of diagnostic histopathology. This is highly relevant because primary treatment decisions are dependent upon the biopsy and not the surgical specimen. Thus, single-cell analysis has the potential to augment traditional core histopathology, improving both the objectivity and accuracy of risk assessment and inform treatment decisions.Significance: Genomic analysis of multiple individual cells harvested from prostate biopsies provides an indepth view of cell populations comprising a prostate neoplasm, yielding novel genomic measures with the potential to improve the accuracy of diagnosis and prognosis in prostate cancer. Cancer Res; 78(2); 348-58. ©2017 AACR.
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Biomarcadores de Tumor/genética , Genómica/métodos , Neoplasias de la Próstata/diagnóstico , Análisis de la Célula Individual/métodos , Anciano , Anciano de 80 o más Años , Humanos , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , Filogenia , Prostatectomía , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/cirugía , Medición de RiesgoRESUMEN
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. Potential cardiotoxicity is the limiting safety parameter to monitor for this bumped kinase inhibitor. This compound is a promising pre-clinical lead for cryptosporidiosis therapy in animals and humans.
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Criptosporidiosis/tratamiento farmacológico , Cryptosporidium parvum/efectos de los fármacos , Inhibidores de Proteínas Quinasas/uso terapéutico , Administración Oral , Animales , Animales Recién Nacidos , Bovinos , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Corazón/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Interferón gamma/genética , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Pruebas de Mutagenicidad , Embarazo , Unión Proteica , Inhibidores de Proteínas Quinasas/administración & dosificación , Inhibidores de Proteínas Quinasas/sangre , Inhibidores de Proteínas Quinasas/toxicidad , SeguridadRESUMEN
Cryptosporidium parvum calcium-dependent protein kinase 1 (CpCDPK1) is a promising target for drug development against cryptosporidiosis. We report a series of low-nanomolar CpCDPK1 5-aminopyrazole-4-carboxamide (AC) scaffold inhibitors that also potently inhibit C. parvum growth in vitro Correlation between anti-CpCDPK1 and C. parvum growth inhibition, as previously reported for pyrazolopyrimidines, was not apparent. Nonetheless, lead AC compounds exhibited a substantial reduction of parasite burden in the neonatal mouse cryptosporidiosis model when dosed at 25 mg/kg.
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Antiprotozoarios/farmacología , Criptosporidiosis/tratamiento farmacológico , Cryptosporidium parvum/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Quinasas/metabolismo , Animales , Antiprotozoarios/química , Criptosporidiosis/parasitología , Cryptosporidium parvum/crecimiento & desarrollo , Ratones , Proteínas Protozoarias/metabolismo , Pirazoles/química , Pirazoles/farmacologíaRESUMEN
There is a substantial need for novel therapeutics to combat the widespread impact caused by Crytosporidium infection. However, there is a lack of knowledge as to which drug pharmacokinetic (PK) characteristics are key to generate an in vivo response, specifically whether systemic drug exposure is crucial for in vivo efficacy. To identify which PK properties are correlated with in vivo efficacy, we generated physiologically based PK models to simulate systemic and gastrointestinal drug concentrations for a series of bumped kinase inhibitors (BKIs) that have nearly identical in vitro potency against Cryptosporidium but display divergent PK properties. When BKI concentrations were used to predict in vivo efficacy with a neonatal model of Cryptosporidium infection, these concentrations in the large intestine were the sole predictors of the observed in vivo efficacy. The significance of large intestinal BKI exposure for predicting in vivo efficacy was further supported with an adult mouse model of Cryptosporidium infection. This study suggests that drug exposure in the large intestine is essential for generating a superior in vivo response, and that physiologically based PK models can assist in the prioritization of leading preclinical drug candidates for in vivo testing.
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Criptosporidiosis/tratamiento farmacológico , Tracto Gastrointestinal/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacocinética , Animales , Cryptosporidium parvum/efectos de los fármacos , Cryptosporidium parvum/aislamiento & purificación , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Tracto Gastrointestinal/metabolismo , Concentración 50 Inhibidora , Ratones , Ratones Noqueados , Modelos Teóricos , Naftalenos/farmacocinética , Piperidinas/farmacocinética , Inhibidores de Proteínas Quinasas/sangre , Pirazoles/farmacocinéticaRESUMEN
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. parvum in vitro. Furthermore, neonatal and interferon γ knockout mouse models of C. parvum infection identified BKIs with in vivo activity. Additional iterative experiments for optimum dosing and selecting BKIs with minimum levels of hERG activity and frequencies of other safety liabilities included those that investigated mammalian cell cytotoxicity, C. parvum proliferation inhibition in vitro, anti-human Src inhibition, hERG activity, in vivo pharmacokinetic data, and efficacy in other mouse models. Findings of this study suggest that fecal concentrations greater than parasite inhibitory concentrations correlate best with effective therapy in the mouse model of cryptosporidiosis, but a more refined model for efficacy is needed.
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Antiprotozoarios/administración & dosificación , Criptosporidiosis/tratamiento farmacológico , Cryptosporidium parvum/efectos de los fármacos , Inhibidores de Proteínas Quinasas/administración & dosificación , Administración Oral , Animales , Diarrea/tratamiento farmacológico , Modelos Animales de Enfermedad , Femenino , Ratones , Ratones Noqueados , Ratones SCIDRESUMEN
Many life-cycle processes in parasites are regulated by protein phosphorylation. Hence, disruption of essential protein kinase function has been explored for therapy of parasitic diseases. However, the difficulty of inhibiting parasite protein kinases to the exclusion of host orthologues poses a practical challenge. A possible path around this difficulty is the use of bumped kinase inhibitors for targeting calcium-dependent protein kinases that contain atypically small gatekeeper residues and are crucial for pathogenic apicomplexan parasites' survival and proliferation. In this article, we review efficacy against the kinase target, parasite growth in vitro, and in animal infection models, as well as the relevant pharmacokinetic and safety parameters of bumped kinase inhibitors.
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Antiprotozoarios/farmacología , Apicomplexa/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/antagonistas & inhibidores , Infecciones por Protozoos/tratamiento farmacológico , Animales , Antiprotozoarios/uso terapéutico , Apicomplexa/enzimología , Bencimidazoles/química , Humanos , Imidazoles/química , Inhibidores de Proteínas Quinasas/uso terapéutico , Infecciones por Protozoos/prevención & control , Piridinas/químicaRESUMEN
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. parvum In the present study, BKIs were screened for efficacy against C. parvum infection in the neonatal mouse model. Three BKIs were then selected for safety and clinical efficacy evaluation in the calf model for cryptosporidiosis. Significant BKI treatment effects were observed for virtually all clinical and parasitological scoring parameters, including diarrhea severity, oocyst shedding, and overall health. These results provide proof of concept for BKIs as therapeutic drug leads in an animal model for human cryptosporidiosis.
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Antiprotozoarios/administración & dosificación , Enfermedades de los Bovinos/tratamiento farmacológico , Criptosporidiosis/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/administración & dosificación , Animales , Animales Recién Nacidos , Antiprotozoarios/efectos adversos , Bovinos , Cryptosporidium parvum/efectos de los fármacos , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Ratones Endogámicos BALB C , Inhibidores de Proteínas Quinasas/efectos adversos , Resultado del TratamientoRESUMEN
Glucokinase enhances glucose conversion to glucose-6-phosphate, causing glucose-stimulated insulin secretion from pancreatic ß cells and increased hepatic glucose uptake. PF-04937319 is a partial glucokinase activator designed to maintain efficacy with reduced hypoglycemia risk. In this randomized, double-blind, double-dummy, 3-period crossover phase 1b study, patients aged 18-70 years with type 2 diabetes mellitus and on metformin received once-daily PF-04937319 (300 mg), split-dose PF-04937319 (150+100 mg; breakfast+lunch), or sitagliptin (100 mg once daily). The primary end point was day 14 weighted mean daily glucose (WMDG) change from period-specific baseline. Secondary end points included change from baseline in fasting plasma glucose, premeal C-peptide and insulin, and safety, including hypoglycemia frequency. Mean decrease from baseline in observed WMDG (mg/dL) was greater for PF-04937319 (split-dose, -31.24; once daily, -31.33) versus sitagliptin (-19.24). Using the integrated glucose red-cell HbA1c model, the observed WMDG effect with both PF-04937319 dosing regimens was projected to yield a clinically superior effect on mean glycated hemoglobin (HbA1c ; split-dose, -0.88%; once daily, -0.94%) compared with sitagliptin (-0.63%). There was no difference in premeal C-peptide or insulin levels, and although the effect on WMDG with both PF-04937319 regimens was similar, the split-dose regimen appeared to offer some advantage in safety and tolerability.
Asunto(s)
Benzofuranos/uso terapéutico , Glucemia/metabolismo , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Activadores de Enzimas/uso terapéutico , Glucoquinasa/metabolismo , Hipoglucemiantes/uso terapéutico , Pirimidinas/uso terapéutico , Adulto , Anciano , Benzofuranos/efectos adversos , Benzofuranos/farmacocinética , Estudios Cruzados , Diabetes Mellitus Tipo 2/sangre , Método Doble Ciego , Determinación de Punto Final , Activadores de Enzimas/efectos adversos , Activadores de Enzimas/farmacocinética , Femenino , Glucoquinasa/efectos de los fármacos , Hemoglobina Glucada , Humanos , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/farmacocinética , Insulina/sangre , Masculino , Metformina/uso terapéutico , Persona de Mediana Edad , Pirimidinas/efectos adversos , Pirimidinas/farmacocinética , Fosfato de Sitagliptina/uso terapéuticoRESUMEN
BACKGROUND: Alloimmunization or the development of alloantibodies to Red Blood Cell (RBC) antigens is considered one of the major complications after RBC transfusions in patients with sickle cell disease (SCD) and can lead to both acute and delayed hemolytic reactions. It has been suggested that polymorphisms in HLA genes, may play a role in alloimmunization. We conducted a retrospective study analyzing the influence of HLA-DRB1 and DQB1 genetic diversity on RBC-alloimmunization. STUDY DESIGN: Two-hundred four multi-transfused SCD patients with and without RBC-alloimmunization were typed at low/medium resolution by PCR-SSO, using IMGT-HLA Database. HLA-DRB1 and DQB1 allele frequencies were analyzed using logistic regression models, and global p-value was calculated using multiple logistic regression. RESULTS: While only trends towards associations between HLA-DR diversity and alloimmunization were observed, analysis of HLA-DQ showed that HLA-DQ2 (p=0.02), -DQ3 (p=0.02) and -DQ5 (p=0.01) alleles were significantly higher in non-alloimmunized patients, likely behaving as protective alleles. In addition, multiple logistic regression analysis showed both HLA-DQ2/6 (p=0.01) and HLA-DQ5/5 (p=0.03) combinations constitute additional predictor of protective status. CONCLUSION: Our data suggest that particular HLA-DQ alleles influence the clinical course of RBC transfusion in patients with SCD, which could pave the way towards predictive strategies.