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1.
PLoS Pathog ; 20(5): e1011835, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38758969

RESUMO

A novel group of biocidal compounds are the Crystal 3D (Cry) and Cytolytic (Cyt) proteins produced by Bacillus thuringiensis (Bt). Some Bt Cry proteins have a selective nematocidal activity, with Cry5B being the most studied. Cry5B kills nematode parasites by binding selectively to membrane glycosphingolipids, then forming pores in the cell membranes of the intestine leading to damage. Cry5B selectively targets multiple species of nematodes from different clades and has no effect against mammalian hosts. Levamisole is a cholinergic anthelmintic that acts by selectively opening L-subtype nicotinic acetylcholine receptor ion-channels (L-AChRs) that have been found on muscles of nematodes. A synergistic nematocidal interaction between levamisole and Cry5B at the whole-worm level has been described previously, but the location, mechanism and time-course of this synergism is not known. In this study we follow the timeline of the effects of levamisole and Cry5B on the Ca2+ levels in enterocyte cells in the intestine of Ascaris suum using fluorescence imaging. The peak Ca2+ responses to levamisole were observed after approximately 10 minutes while the peak responses to activated Cry5B were observed after approximately 80 minutes. When levamisole and Cry5B were applied simultaneously, we observed that the responses to Cry5B were bigger and occurred sooner than when it was applied by itself. It is proposed that the synergism is due to the cytoplasmic Ca2+ overload that is induced by the combination of levamisole opening Ca2+ permeable L-subtype nAChRs and the Ca2+ permeable Cry5B toxin pores produced in the enterocyte plasma membranes. The effect of levamisole potentiates and speeds the actions of Cry5B that gives rise to bigger Ca2+ overloads that accelerates cell-death of the enterocytes.


Assuntos
Ascaris suum , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias , Endotoxinas , Proteínas Hemolisinas , Levamisol , Levamisol/farmacologia , Animais , Toxinas de Bacillus thuringiensis/farmacologia , Endotoxinas/farmacologia , Endotoxinas/metabolismo , Proteínas Hemolisinas/farmacologia , Proteínas Hemolisinas/metabolismo , Proteínas de Bactérias/metabolismo , Ascaris suum/efeitos dos fármacos , Anti-Helmínticos/farmacologia , Intestinos/efeitos dos fármacos , Intestinos/parasitologia , Sinergismo Farmacológico , Antinematódeos/farmacologia , Bacillus thuringiensis/efeitos dos fármacos
2.
Proc Natl Acad Sci U S A ; 119(34): e2111932119, 2022 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-35969762

RESUMO

Glutamate-gated chloride channels (GluCls) are unique to invertebrates and are targeted by macrocyclic lactones. In this study, we cloned an AVR-14B GluCl subunit from adult Brugia malayi, a causative agent of lymphatic filariasis in humans. To elucidate this channel's pharmacological properties, we used Xenopus laevis oocytes for expression and performed two-electrode voltage-clamp electrophysiology. The receptor was gated by the natural ligand L-glutamate (effective concentration, 50% [EC50] = 0.4 mM) and ivermectin (IVM; EC50 = 1.8 nM). We also characterized the effects of nodulisporic acid (NA) on Bma-AVR-14B and NA-produced dual effects on the receptor as an agonist and a type II positive allosteric modulator. Here we report characterization of the complex activity of NA on a nematode GluCl. Bma-AVR-14B demonstrated some unique pharmacological characteristics. IVM did not produce potentiation of L-glutamate-mediated responses but instead, reduced the channel's sensitivity for the ligand. Further electrophysiological exploration showed that IVM (at a moderate concentration of 0.1 nM) functioned as an inhibitor of both agonist and positive allosteric modulatory effects of NA. This suggests that IVM and NA share a complex interaction. The pharmacological properties of Bma-AVR-14B indicate that the channel is an important target of IVM and NA. In addition, the unique electrophysiological characteristics of Bma-AVR-14B could explain the observed variation in drug sensitivities of various nematode parasites. We have also shown the inhibitory effects of IVM and NA on adult worm motility using Worminator. RNA interference (RNAi) knockdown suggests that AVR-14 plays a role in influencing locomotion in B. malayi.


Assuntos
Brugia Malayi , Canais de Cloreto , Indóis , Animais , Brugia Malayi/efeitos dos fármacos , Brugia Malayi/genética , Brugia Malayi/metabolismo , Canais de Cloreto/efeitos dos fármacos , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Ácido Glutâmico/metabolismo , Indóis/farmacologia , Ivermectina/farmacologia , Ligantes
3.
Antimicrob Agents Chemother ; 67(10): e0041923, 2023 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-37728916

RESUMO

Filarial nematode infections are a major health concern in several countries. Lymphatic filariasis is caused by Wuchereria bancrofti and Brugia spp. affecting over 120 million people. Heavy infections can lead to elephantiasis, which has serious effects on individuals' lives. Although current anthelmintics are effective at killing microfilariae in the bloodstream, they have little to no effect against adult parasites found in the lymphatic system. The anthelmintic diethylcarbamazine is one of the central pillars of lymphatic filariasis control. Recent studies have reported that diethylcarbamazine can open transient receptor potential (TRP) channels in the muscles of adult female Brugia malayi, leading to contraction and paralysis. Diethylcarbamazine has synergistic effects in combination with emodepside on Brugia, inhibiting motility: emodepside is an anthelmintic that has effects on filarial nematodes and is under trial for the treatment of river blindness. Here, we have studied the effects of diethylcarbamazine on single Brugia muscle cells by measuring the change in Ca2+ fluorescence in the muscle using Ca2+-imaging techniques. Diethylcarbamazine interacts with the transient receptor potential channel, C classification (TRPC) ortholog receptor TRP-2 to promote Ca2+ entry into the Brugia muscle cells, which can activate Slopoke (SLO-1) Ca2+-activated K+ channels, the putative target of emodepside. A combination of diethylcarbamazine and emodepside leads to a bigger Ca2+ signal than when either compound is applied alone. Our study shows that diethylcarbamazine targets TRP channels to promote Ca2+ entry that is increased by emodepside activation of SLO-1 K+ channels.


Assuntos
Anti-Helmínticos , Brugia Malayi , Filariose Linfática , Canais de Potencial de Receptor Transitório , Animais , Adulto , Feminino , Humanos , Dietilcarbamazina/farmacologia , Dietilcarbamazina/uso terapêutico , Brugia Malayi/fisiologia , Filariose Linfática/tratamento farmacológico , Filariose Linfática/parasitologia , Canais de Potencial de Receptor Transitório/farmacologia , Canais de Potencial de Receptor Transitório/uso terapêutico , Anti-Helmínticos/farmacologia , Músculos
4.
PLoS Pathog ; 16(4): e1008396, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32243475

RESUMO

Nematode parasites infect approximately 1.5 billion people globally and are a significant public health concern. There is an accepted need for new, more effective anthelmintic drugs. Nicotinic acetylcholine receptors on parasite nerve and somatic muscle are targets of the cholinomimetic anthelmintics, while glutamate-gated chloride channels in the pharynx of the nematode are affected by the avermectins. Here we describe a novel nicotinic acetylcholine receptor on the nematode pharynx that is a potential new drug target. This homomeric receptor is comprised of five non-α EAT-2 subunits and is not sensitive to existing cholinomimetic anthelmintics. We found that EAT-18, a novel auxiliary subunit protein, is essential for functional expression of the receptor. EAT-18 directly interacts with the mature receptor, and different homologs alter the pharmacological properties. Thus we have described not only a novel potential drug target but also a new type of obligate auxiliary protein for nAChRs.


Assuntos
Antinematódeos/farmacologia , Ascaris suum/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Helminto/metabolismo , Faringe/metabolismo , Receptores Nicotínicos/metabolismo , Acetilcolina/farmacologia , Animais , Ascaris suum/efeitos dos fármacos , Ascaris suum/genética , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/genética , Proteínas de Helminto/genética , Faringe/efeitos dos fármacos , Receptores Nicotínicos/genética
5.
Genet Med ; 24(4): 798-810, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35065883

RESUMO

Re-analyzing genomic information from a patient suspected of having an underlying genetic condition can improve the diagnostic yield of sequencing tests, potentially providing significant benefits to the patient and to the health care system. Although a significant number of studies have shown the clinical potential of re-analysis, less work has been performed to characterize the mechanisms responsible for driving the increases in diagnostic yield. Complexities surrounding re-analysis have also emerged. The terminology itself represents a challenge because "re-analysis" can refer to a range of different concepts. Other challenges include the increased workload that re-analysis demands of curators, adequate reimbursement pathways for clinical and diagnostic services, and the development of systems to handle large volumes of data. Re-analysis also raises ethical implications for patients and families, most notably when re-classification of a variant alters diagnosis, treatment, and prognosis. This review highlights the possibilities and complexities associated with the re-analysis of existing clinical genomic data. We propose a terminology that builds on the foundation presented in a recent statement from the American College of Medical Genetics and Genomics and describes each re-analysis process. We identify mechanisms for increasing diagnostic yield and provide perspectives on the range of challenges that must be addressed by health care systems and individual patients.


Assuntos
Genômica , Humanos , Estados Unidos
6.
BMC Cancer ; 22(1): 85, 2022 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-35057759

RESUMO

BACKGROUND: Circulating cell-free DNA (cfDNA) in the plasma of cancer patients contains cell-free tumour DNA (ctDNA) derived from tumour cells and it has been widely recognized as a non-invasive source of tumour DNA for diagnosis and prognosis of cancer. Molecular profiling of ctDNA is often performed using targeted sequencing or low-coverage whole genome sequencing (WGS) to identify tumour specific somatic mutations or somatic copy number aberrations (sCNAs). However, these approaches cannot efficiently detect all tumour-derived genomic changes in ctDNA. METHODS: We performed WGS analysis of cfDNA from 4 breast cancer patients and 2 patients with benign tumours. We sequenced matched germline DNA for all 6 patients and tumour samples from the breast cancer patients. All samples were sequenced on Illumina HiSeqXTen sequencing platform and achieved approximately 30x, 60x and 100x coverage on germline, tumour and plasma DNA samples, respectively. RESULTS: The mutational burden of the plasma samples (1.44 somatic mutations/Mb of genome) was higher than the matched tumour samples. However, 90% of high confidence somatic cfDNA variants were not detected in matched tumour samples and were found to comprise two background plasma mutational signatures. In contrast, cfDNA from the di-nucleosome fraction (300 bp-350 bp) had much higher proportion (30%) of variants shared with tumour. Despite high coverage sequencing we were unable to detect sCNAs in plasma samples. CONCLUSIONS: Deep sequencing analysis of plasma samples revealed higher fraction of unique somatic mutations in plasma samples, which were not detected in matched tumour samples. Sequencing of di-nucleosome bound cfDNA fragments may increase recovery of tumour mutations from plasma.


Assuntos
Neoplasias da Mama/genética , DNA Tumoral Circulante/sangue , Análise Mutacional de DNA/métodos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Sequenciamento Completo do Genoma/métodos , Adulto , Biomarcadores Tumorais/genética , Neoplasias da Mama/sangue , Feminino , Humanos , Mutação , Prognóstico
7.
Bioorg Med Chem Lett ; 74: 128942, 2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-35973549

RESUMO

The discovery of a dual MAO-B/SSAO inhibitor PXS-5131 is reported. The compound offers a compact and rigid three-dimensional structure with superior selectivity over MAO-A. Potency and selectivity are linked to both the double bond geometry and stereochemistry of the allylamine moiety, highlighting the importance of optimal set up of these features in the class of amine oxidase inhibitors. PXS-5131 possesses an attractive preclinical pharmacokinetic profile and has anti-inflammatory properties in models of acute inflammation and neuroinflammation.


Assuntos
Amina Oxidase (contendo Cobre) , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Monoaminoxidase , Inibidores da Monoaminoxidase/farmacologia
8.
Nature ; 538(7626): 477-482, 2016 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-27760111

RESUMO

Avoidance of apoptosis is critical for the development and sustained growth of tumours. The pro-survival protein myeloid cell leukemia 1 (MCL1) is overexpressed in many cancers, but the development of small molecules targeting this protein that are amenable for clinical testing has been challenging. Here we describe S63845, a small molecule that specifically binds with high affinity to the BH3-binding groove of MCL1. Our mechanistic studies demonstrate that S63845 potently kills MCL1-dependent cancer cells, including multiple myeloma, leukaemia and lymphoma cells, by activating the BAX/BAK-dependent mitochondrial apoptotic pathway. In vivo, S63845 shows potent anti-tumour activity with an acceptable safety margin as a single agent in several cancers. Moreover, MCL1 inhibition, either alone or in combination with other anti-cancer drugs, proved effective against several solid cancer-derived cell lines. These results point towards MCL1 as a target for the treatment of a wide range of tumours.


Assuntos
Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Modelos Biológicos , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Tiofenos/farmacologia , Tiofenos/uso terapêutico , Animais , Antineoplásicos/administração & dosagem , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Feminino , Humanos , Leucemia/tratamento farmacológico , Leucemia/metabolismo , Leucemia/patologia , Linfoma/tratamento farmacológico , Linfoma/metabolismo , Linfoma/patologia , Masculino , Camundongos , Modelos Moleculares , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Neoplasias/metabolismo , Pirimidinas/administração & dosagem , Tiofenos/administração & dosagem , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
9.
Nature ; 531(7592): 47-52, 2016 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-26909576

RESUMO

Integrated genomic analysis of 456 pancreatic ductal adenocarcinomas identified 32 recurrently mutated genes that aggregate into 10 pathways: KRAS, TGF-ß, WNT, NOTCH, ROBO/SLIT signalling, G1/S transition, SWI-SNF, chromatin modification, DNA repair and RNA processing. Expression analysis defined 4 subtypes: (1) squamous; (2) pancreatic progenitor; (3) immunogenic; and (4) aberrantly differentiated endocrine exocrine (ADEX) that correlate with histopathological characteristics. Squamous tumours are enriched for TP53 and KDM6A mutations, upregulation of the TP63∆N transcriptional network, hypermethylation of pancreatic endodermal cell-fate determining genes and have a poor prognosis. Pancreatic progenitor tumours preferentially express genes involved in early pancreatic development (FOXA2/3, PDX1 and MNX1). ADEX tumours displayed upregulation of genes that regulate networks involved in KRAS activation, exocrine (NR5A2 and RBPJL), and endocrine differentiation (NEUROD1 and NKX2-2). Immunogenic tumours contained upregulated immune networks including pathways involved in acquired immune suppression. These data infer differences in the molecular evolution of pancreatic cancer subtypes and identify opportunities for therapeutic development.


Assuntos
Genes Neoplásicos/genética , Genoma Humano/genética , Genômica , Mutação/genética , Neoplasias Pancreáticas/classificação , Neoplasias Pancreáticas/genética , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Carcinoma Ductal Pancreático/classificação , Carcinoma Ductal Pancreático/genética , Carcinoma Ductal Pancreático/imunologia , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Metilação de DNA , Proteínas de Ligação a DNA/genética , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Fator 3-beta Nuclear de Hepatócito/genética , Fator 3-gama Nuclear de Hepatócito/genética , Histona Desmetilases/genética , Proteína Homeobox Nkx-2.2 , Proteínas de Homeodomínio/genética , Humanos , Camundongos , Proteínas Nucleares/genética , Neoplasias Pancreáticas/imunologia , Neoplasias Pancreáticas/metabolismo , Neoplasias Pancreáticas/patologia , Prognóstico , Receptores Citoplasmáticos e Nucleares/genética , Análise de Sobrevida , Transativadores/genética , Fatores de Transcrição/genética , Transcrição Gênica , Transcriptoma , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/genética , Proteínas de Peixe-Zebra
10.
PLoS Pathog ; 15(9): e1008041, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31553770

RESUMO

Filariae are parasitic nematodes that are transmitted to their definitive host as third-stage larvae by arthropod vectors like mosquitoes. Filariae cause diseases including: lymphatic filariasis with distressing and disturbing symptoms like elephantiasis; and river blindness. Filarial diseases affect millions of people in 73 countries throughout the topics and sub-tropics. The drugs available for mass drug administration, (ivermectin, albendazole and diethylcarbamazine), are ineffective against adult filariae (macrofilariae) at the registered dosing regimen; this generates a real and urgent need to identify effective macrofilaricides. Emodepside, a veterinary anthelmintic registered for treatment of nematode infections in cats and dogs, is reported to have macrofilaricidal effects. Here, we explore the mode of action of emodepside using adult Brugia malayi, one of the species that causes lymphatic filariasis. Whole-parasite motility measurement with Worminator and patch-clamp of single muscle cells show that emodepside potently inhibits motility by activating voltage-gated potassium channels and that the male is more sensitive than the female. RNAi knock down suggests that emodepside targets SLO-1 K channels. We expressed slo-1 isoforms, with alternatively spliced exons at the RCK1 (Regulator of Conductance of Potassium) domain, heterologously in Xenopus laevis oocytes. We discovered that the slo-1f isoform, found in muscles of males, is more sensitive to emodepside than the slo-1a isoform found in muscles of females; and selective RNAi of the slo-1a isoform in female worms increased emodepside potency. In Onchocerca volvulus, that causes river blindness, we found two isoforms in adult females with homology to Bma-SLO-1A and Bma-SLO-1F at the RCK1 domain. In silico modeling identified an emodepside binding pocket in the same RCK1 region of different species of filaria that is affected by these splice variations. Our observations show that emodepside has potent macrofilaricidal effects and alternative splicing in the RCK1 binding pocket affects potency. Therefore, the evaluation of potential sex-dependent effects of an anthelmintic compound is of importance to prevent any under-dosing of one or the other gender of nematodes once given to patients.


Assuntos
Brugia Malayi/efeitos dos fármacos , Brugia Malayi/fisiologia , Depsipeptídeos/farmacologia , Filaricidas/farmacologia , Canais de Potássio Ativados por Cálcio de Condutância Alta/metabolismo , Processamento Alternativo , Sequência de Aminoácidos , Animais , Sítios de Ligação/genética , Brugia Malayi/genética , Feminino , Filariose/tratamento farmacológico , Filariose/parasitologia , Técnicas de Silenciamento de Genes , Humanos , Canais de Potássio Ativados por Cálcio de Condutância Alta/química , Canais de Potássio Ativados por Cálcio de Condutância Alta/genética , Masculino , Modelos Moleculares , Movimento/efeitos dos fármacos , Movimento/fisiologia , Músculos/efeitos dos fármacos , Músculos/fisiologia , Peptídeos/farmacologia , Bloqueadores dos Canais de Potássio/farmacologia , Homologia de Sequência de Aminoácidos , Fatores Sexuais
11.
Nature ; 518(7540): 495-501, 2015 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-25719666

RESUMO

Pancreatic cancer remains one of the most lethal of malignancies and a major health burden. We performed whole-genome sequencing and copy number variation (CNV) analysis of 100 pancreatic ductal adenocarcinomas (PDACs). Chromosomal rearrangements leading to gene disruption were prevalent, affecting genes known to be important in pancreatic cancer (TP53, SMAD4, CDKN2A, ARID1A and ROBO2) and new candidate drivers of pancreatic carcinogenesis (KDM6A and PREX2). Patterns of structural variation (variation in chromosomal structure) classified PDACs into 4 subtypes with potential clinical utility: the subtypes were termed stable, locally rearranged, scattered and unstable. A significant proportion harboured focal amplifications, many of which contained druggable oncogenes (ERBB2, MET, FGFR1, CDK6, PIK3R3 and PIK3CA), but at low individual patient prevalence. Genomic instability co-segregated with inactivation of DNA maintenance genes (BRCA1, BRCA2 or PALB2) and a mutational signature of DNA damage repair deficiency. Of 8 patients who received platinum therapy, 4 of 5 individuals with these measures of defective DNA maintenance responded.


Assuntos
Análise Mutacional de DNA , Genoma Humano/genética , Genômica , Mutação/genética , Neoplasias Pancreáticas/genética , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/genética , Animais , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/genética , Reparo do DNA/genética , Feminino , Genes BRCA1 , Genes BRCA2 , Marcadores Genéticos/genética , Instabilidade Genômica/genética , Genótipo , Humanos , Camundongos , Neoplasias Pancreáticas/classificação , Neoplasias Pancreáticas/tratamento farmacológico , Platina/farmacologia , Mutação Puntual/genética , Inibidores de Poli(ADP-Ribose) Polimerases , Ensaios Antitumorais Modelo de Xenoenxerto
12.
J Pharmacol Exp Ther ; 374(3): 489-498, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32576599

RESUMO

Facioscapulohumeral muscular dystrophy (FSHD) is caused by the loss of repression at the D4Z4 locus leading to aberrant double homeobox 4 (DUX4) expression in skeletal muscle. Activation of this early embryonic transcription factor results in the expression of its target genes causing muscle fiber death. Although progress toward understanding the signals driving DUX4 expression has been made, the factors and pathways involved in the transcriptional activation of this gene remain largely unknown. Here, we describe the identification and characterization of p38α as a novel regulator of DUX4 expression in FSHD myotubes. By using multiple highly characterized, potent, and specific inhibitors of p38α/ß, we show a robust reduction of DUX4 expression, activity, and cell death across patient-derived FSHD1 and FSHD2 lines. RNA-seq profiling reveals that a small number of genes are differentially expressed upon p38α/ß inhibition, the vast majority of which are DUX4 target genes. Our results reveal a novel and apparently critical role for p38α in the aberrant activation of DUX4 in FSHD and support the potential of p38α/ß inhibitors as effective therapeutics to treat FSHD at its root cause. SIGNIFICANCE STATEMENT: Using patient-derived facioscapulohumeral muscular dystrophy (FSHD) myotubes, we characterize the pharmacological relationships between p38α/ß inhibition, double homeobox 4 (DUX4) expression, its downstream transcriptional program, and muscle cell death. p38α/ß inhibition results in potent and specific DUX4 downregulation across multiple genotypes without significant effects in the process of myogenesis in vitro. These findings highlight the potential of p38α/ß inhibitors for the treatment of FSHD, a condition that today has no approved therapies.


Assuntos
Proteínas de Homeodomínio/metabolismo , Distrofia Muscular Facioescapuloumeral/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Morte Celular/fisiologia , Linhagem Celular , Regulação da Expressão Gênica/fisiologia , Humanos , Células Musculares/metabolismo , Músculo Esquelético/metabolismo
13.
Proc Natl Acad Sci U S A ; 114(21): 5539-5544, 2017 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-28487481

RESUMO

Many techniques for studying functional genomics of important target sites of anthelmintics have been restricted to Caenorhabditis elegans because they have failed when applied to animal parasites. To overcome these limitations, we have focused our research on the human nematode parasite Brugia malayi, which causes elephantiasis. Here, we combine single-cell PCR, whole muscle cell patch clamp, motility phenotyping (Worminator), and dsRNA for RNAi for functional genomic studies that have revealed, in vivo, four different muscle nAChRs (M-, L-, P-, and N-). The cholinergic anthelmintics had different selectivities for these receptors. We show that motility and patch-clamp responses to levamisole and pyrantel, but not morantel or nicotine, require the unc-38 and/or unc-29 genes. Derquantel behaved as a competitive antagonist and distinguished M-nAChRs activated by morantel (Kb 13.9 nM), P-nAChRs activated by pyrantel (Kb 126 nM), and L-nAChRs activated by levamisole (Kb 0.96 µM) and bephenium. Derquantel was a noncompetitive antagonist of nicotine, revealing N-type nAChRs. The presence of four diverse nAChRs on muscle is perhaps surprising and not predicted from the C. elegans model. The diverse nAChRs represent distinguishable drug targets with different functions: Knockdown of unc-38+unc-29 (L- and/or P-receptors) inhibited motility but knockdown of acr-16+acr-26 (M- and/or N-receptors) did not.


Assuntos
Antinematódeos/farmacologia , Brugia Malayi/efeitos dos fármacos , Receptores Nicotínicos/metabolismo , Aminoacetonitrila/análogos & derivados , Animais , Brugia Malayi/genética , Brugia Malayi/metabolismo , Filariose Linfática/parasitologia , Feminino , Técnicas de Silenciamento de Genes , Indóis , Levamisol , Locomoção/efeitos dos fármacos , Músculos/metabolismo , Agonistas Nicotínicos , Antagonistas Nicotínicos , Oxepinas , Pirantel , Análise de Célula Única
14.
Nucleic Acids Res ; 45(5): e34, 2017 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-27903916

RESUMO

Accurate identification of copy number alterations is an essential step in understanding the events driving tumor progression. While a variety of algorithms have been developed to use high-throughput sequencing data to profile copy number changes, no tool is able to reliably characterize ploidy and genotype absolute copy number from tumor samples that contain less than 40% tumor cells. To increase our power to resolve the copy number profile from low-cellularity tumor samples, we developed a novel approach that pre-phases heterozygote germline single nucleotide polymorphisms (SNPs) in order to replace the commonly used 'B-allele frequency' with a more powerful 'parental-haplotype frequency'. We apply our tool-sCNAphase-to characterize the copy number and loss-of-heterozygosity profiles of four publicly available breast cancer cell-lines. Comparisons to previous spectral karyotyping and microarray studies revealed that sCNAphase reliably identified overall ploidy as well as the individual copy number mutations from each cell-line. Analysis of artificial cell-line mixtures demonstrated the capacity of this method to determine the level of tumor cellularity, consistently identify sCNAs and characterize ploidy in samples with as little as 10% tumor cells. This novel methodology has the potential to bring sCNA profiling to low-cellularity tumors, a form of cancer unable to be accurately studied by current methods.


Assuntos
Aneuploidia , Variações do Número de Cópias de DNA , Haplótipos , Software , Algoritmos , Contagem de Células , Linhagem Celular Tumoral , Dosagem de Genes , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Análise de Sequência de DNA
15.
J Pharmacol Exp Ther ; 358(1): 125-37, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27189974

RESUMO

The amyloid-ß peptide (Aß)-in particular, the 42-amino acid form, Aß1-42-is thought to play a key role in the pathogenesis of Alzheimer's disease (AD). Thus, several therapeutic modalities aiming to inhibit Aß synthesis or increase the clearance of Aß have entered clinical trials, including γ-secretase inhibitors, anti-Aß antibodies, and amyloid-ß precursor protein cleaving enzyme inhibitors. A unique class of small molecules, γ-secretase modulators (GSMs), selectively reduce Aß1-42 production, and may also decrease Aß1-40 while simultaneously increasing one or more shorter Aß peptides, such as Aß1-38 and Aß1-37. GSMs are particularly attractive because they do not alter the total amount of Aß peptides produced by γ-secretase activity; they spare the processing of other γ-secretase substrates, such as Notch; and they do not cause accumulation of the potentially toxic processing intermediate, ß-C-terminal fragment. This report describes the translation of pharmacological activity across species for two novel GSMs, (S)-7-(4-fluorophenyl)-N2-(3-methoxy-4-(3-methyl-1H-1,2,4-triazol-1-yl)phenyl)-N4-methyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine-2,4-diamine (BMS-932481) and (S,Z)-17-(4-chloro-2-fluorophenyl)-34-(3-methyl-1H-1,2,4-triazol-1-yl)-16,17-dihydro-15H-4-oxa-2,9-diaza-1(2,4)-cyclopenta[d]pyrimidina-3(1,3)-benzenacyclononaphan-6-ene (BMS-986133). These GSMs are highly potent in vitro, exhibit dose- and time-dependent activity in vivo, and have consistent levels of pharmacological effect across rats, dogs, monkeys, and human subjects. In rats, the two GSMs exhibit similar pharmacokinetics/pharmacodynamics between the brain and cerebrospinal fluid. In all species, GSM treatment decreased Aß1-42 and Aß1-40 levels while increasing Aß1-38 and Aß1-37 by a corresponding amount. Thus, the GSM mechanism and central activity translate across preclinical species and humans, thereby validating this therapeutic modality for potential utility in AD.


Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Compostos de Anilina/farmacologia , Compostos de Anilina/farmacocinética , Encéfalo/efeitos dos fármacos , Hidrocarbonetos Aromáticos com Pontes/farmacologia , Hidrocarbonetos Aromáticos com Pontes/farmacocinética , Pirimidinas/farmacologia , Pirimidinas/farmacocinética , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Peptídeos beta-Amiloides/genética , Compostos de Anilina/química , Animais , Encéfalo/enzimologia , Encéfalo/metabolismo , Hidrocarbonetos Aromáticos com Pontes/química , Linhagem Celular , Cães , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Macaca fascicularis , Pirimidinas/química , Ratos Sprague-Dawley , Receptores Notch/metabolismo , Especificidade da Espécie , Distribuição Tecidual
16.
PLoS Pathog ; 10(6): e1004181, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24945827

RESUMO

Acetylcholine is the canonical excitatory neurotransmitter of the mammalian neuromuscular system. However, in the trematode parasite Schistosoma mansoni, cholinergic stimulation leads to muscle relaxation and a flaccid paralysis, suggesting an inhibitory mode of action. Information about the pharmacological mechanism of this inhibition is lacking. Here, we used a combination of techniques to assess the role of cholinergic receptors in schistosome motor function. The neuromuscular effects of acetylcholine are typically mediated by gated cation channels of the nicotinic receptor (nAChR) family. Bioinformatics analyses identified numerous nAChR subunits in the S. mansoni genome but, interestingly, nearly half of these subunits carried a motif normally associated with chloride-selectivity. These putative schistosome acetylcholine-gated chloride channels (SmACCs) are evolutionarily divergent from those of nematodes and form a unique clade within the larger family of nAChRs. Pharmacological and RNA interference (RNAi) behavioral screens were used to assess the role of the SmACCs in larval motor function. Treatment with antagonists produced the same effect as RNAi suppression of SmACCs; both led to a hypermotile phenotype consistent with abrogation of an inhibitory neuromuscular mediator. Antibodies were then generated against two of the SmACCs for use in immunolocalization studies. SmACC-1 and SmACC-2 localize to regions of the peripheral nervous system that innervate the body wall muscles, yet neither appears to be expressed directly on the musculature. One gene, SmACC-1, was expressed in HEK-293 cells and characterized using an iodide flux assay. The results indicate that SmACC-1 formed a functional homomeric chloride channel and was activated selectively by a panel of cholinergic agonists. The results described in this study identify a novel clade of nicotinic chloride channels that act as inhibitory modulators of schistosome neuromuscular function. Additionally, the iodide flux assay used to characterize SmACC-1 represents a new high-throughput tool for drug screening against these unique parasite ion channels.


Assuntos
Canais de Cloreto/antagonistas & inibidores , Agonistas Colinérgicos/farmacologia , Atividade Motora/efeitos dos fármacos , Antagonistas Nicotínicos/farmacologia , Schistosoma mansoni/metabolismo , Acetilcolina/metabolismo , Animais , Anti-Helmínticos/uso terapêutico , Linhagem Celular , Canais de Cloreto/genética , Canais de Cloreto/metabolismo , Células HEK293 , Humanos , Atividade Motora/genética , Praziquantel/uso terapêutico , Interferência de RNA , RNA Interferente Pequeno , Receptores Colinérgicos/genética , Receptores Nicotínicos/genética , Schistosoma mansoni/genética , Esquistossomose/tratamento farmacológico , Esquistossomose/patologia
17.
PLoS Pathog ; 10(1): e1003870, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24497826

RESUMO

Nicotinic acetylcholine receptors (nAChRs) of parasitic nematodes are required for body movement and are targets of important "classical" anthelmintics like levamisole and pyrantel, as well as "novel" anthelmintics like tribendimidine and derquantel. Four biophysical subtypes of nAChR have been observed electrophysiologically in body muscle of the nematode parasite Oesophagostomum dentatum, but their molecular basis was not understood. Additionally, loss of one of these subtypes (G 35 pS) was found to be associated with levamisole resistance. In the present study, we identified and expressed in Xenopus oocytes, four O. dentatum nAChR subunit genes, Ode-unc-38, Ode-unc-63, Ode-unc-29 and Ode-acr-8, to explore the origin of the receptor diversity. When different combinations of subunits were injected in Xenopus oocytes, we reconstituted and characterized four pharmacologically different types of nAChRs with different sensitivities to the cholinergic anthelmintics. Moreover, we demonstrate that the receptor diversity may be affected by the stoichiometric arrangement of the subunits. We show, for the first time, different combinations of subunits from a parasitic nematode that make up receptors sensitive to tribendimidine and derquantel. In addition, we report that the recombinant levamisole-sensitive receptor made up of Ode-UNC-29, Ode-UNC-63, Ode-UNC-38 and Ode-ACR-8 subunits has the same single-channel conductance, 35 pS and 2.4 ms mean open-time properties, as the levamisole-AChR (G35) subtype previously identified in vivo. These data highlight the flexible arrangements of the receptor subunits and their effects on sensitivity and resistance to the cholinergic anthelmintics; pyrantel, tribendimidine and/or derquantel may still be effective on levamisole-resistant worms.


Assuntos
Anti-Helmínticos/farmacologia , Proteínas de Helminto/metabolismo , Indóis/farmacologia , Nematoides/metabolismo , Oxepinas/farmacologia , Fenilenodiaminas/farmacologia , Receptores Nicotínicos/metabolismo , Animais , Proteínas de Helminto/genética , Nematoides/genética , Receptores Nicotínicos/genética , Xenopus laevis
18.
Parasitol Res ; 114(8): 3059-68, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25944741

RESUMO

Essential plant oils (or their active principles) are safe to use and a potentially attractive alternative to current antiparasitic drugs. In the present study, we tested the effects of carvacrol on the isolated tissues of Ascaris suum and investigated potential interactions with other antiparasitic drugs. We used somatic muscle flaps for contraction assays, as well as for electrophysiological investigations. Carvacrol 300 µM highly significantly inhibited contractions caused by 1, 3, 10, 30, and 100 µM of ACh (p = 0.0023, p = 0.0002, p = 0.0002, p < 0.0001, and p < 0.0001). The control EC50 for acetylcholine was 8.87 µM (log EC50 = 0.95 ± 0.26), while R max was 2.53 ± 0.24 g. The EC50 of acetylcholine in the presence of 300 µM of carvacrol was 27.71 µM (log EC50 = 1.44 ± 0.28) and the R max decreased to 1.63 ± 0.32 g. Furthermore, carvacrol highly significant potentiates inhibitory effect of GABA and piperazine on the contractions induced by ACh. However, carvacrol (100 and 300 µM), did not produce any changes in the membrane potential or conductance of the A. suum muscle cell. While, 300 µM of carvacrol showed a significant inhibitory effect on ACh-induced depolarization response. The mean control depolarization was 13.58 ± 0.66 mV and decreased in presence of carvacrol to 4.50 ± 1.02 mV (p < 0.0001). Mean control Δg was 0.168 ± 0.017 µS, while in the presence of 300 µM of carvacrol, Δg significantly decreased to 0.060 ± 0.018 ΔS (p = 0.0017). The inhibitory effect on contractions may be the explanation of the antinematodal potential of carvacrol. Moreover, inhibition of depolarizations caused by ACh and reduction of conductance changes directly points to an interaction with the nAChR in A. suum.


Assuntos
Antinematódeos/farmacologia , Ascaris suum/efeitos dos fármacos , Monoterpenos/farmacologia , Receptores de GABA/metabolismo , Receptores Nicotínicos/metabolismo , Acetilcolina/metabolismo , Animais , Antinematódeos/química , Cimenos , Potenciais da Membrana/efeitos dos fármacos , Monoterpenos/química , Músculos/efeitos dos fármacos
19.
JMIR Bioinform Biotechnol ; 5: e55632, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38935958

RESUMO

Health care is at a turning point. We are shifting from protocolized medicine to precision medicine, and digital health systems are facilitating this shift. By providing clinicians with detailed information for each patient and analytic support for decision-making at the point of care, digital health technologies are enabling a new era of precision medicine. Genomic data also provide clinicians with information that can improve the accuracy and timeliness of diagnosis, optimize prescribing, and target risk reduction strategies, all of which are key elements for precision medicine. However, genomic data are predominantly seen as diagnostic information and are not routinely integrated into the clinical workflows of electronic medical records. The use of genomic data holds significant potential for precision medicine; however, as genomic data are fundamentally different from the information collected during routine practice, special considerations are needed to use this information in a digital health setting. This paper outlines the potential of genomic data integration with electronic records, and how these data can enable precision medicine.

20.
Sci Rep ; 14(1): 7717, 2024 04 02.
Artigo em Inglês | MEDLINE | ID: mdl-38565608

RESUMO

Despite the significant advances in understanding the genetic architecture of epilepsy, many patients do not receive a molecular diagnosis after genomic testing. Re-analysing existing genomic data has emerged as a potent method to increase diagnostic yields-providing the benefits of genomic-enabled medicine to more individuals afflicted with a range of different conditions. The primary drivers for these new diagnoses are the discovery of novel gene-disease and variants-disease relationships; however, most decisions to trigger re-analysis are based on the passage of time rather than the accumulation of new knowledge. To explore how our understanding of a specific condition changes and how this impacts re-analysis of genomic data from epilepsy patients, we developed Vigelint. This approach combines the information from PanelApp and ClinVar to characterise how the clinically relevant genes and causative variants available to laboratories change over time, and this approach to five clinical-grade epilepsy panels. Applying the Vigelint pipeline to these panels revealed highly variable patterns in new, clinically relevant knowledge becoming publicly available. This variability indicates that a more dynamic approach to re-analysis may benefit the diagnosis and treatment of epilepsy patients. Moreover, this work suggests that Vigelint can provide empirical data to guide more nuanced, condition-specific approaches to re-analysis.


Assuntos
Epilepsia , Humanos , Epilepsia/diagnóstico , Epilepsia/genética , Genômica , Testes Genéticos
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