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1.
Neurochem Int ; 126: 19-26, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-30831216

RESUMEN

Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease caused by selective motor neuron death. Mutations in the gene encoding copper/zinc superoxide dismutase (SOD1) belong to one of the four major mutation clusters responsible for pathogenesis of ALS. Toxic gain-of-function (not loss-of-function) of SOD1 mutants causes motor neuron degeneration. Aberrant protein-protein interactions (PPI) between mutant SOD1 and other proteins are involved in this toxic gain-of-function. Therefore, PPI inhibitors of mutant SOD1 not only increase understanding of ALS pathogenesis, but can also be used as novel therapeutics for ALS. Although it is challenging to identify PPI inhibitors, prior knowledge of the binding site can increase success probability. We have previously reported that tubulin interacts with N-terminal residues 1-23 of mutant SOD1. In the present study, we performed virtual screening by docking simulation of 32,791 compounds using this N-terminal binding site as prior knowledge. An established assay system for interaction inhibition between mutant SOD1-tubulin was used as an in-house model system to identify mutant SOD1 PPI inhibitors, with the goal of developing novel therapeutics for ALS. Consequently, five of six assay-executable compounds among top-ranked compounds during docking simulation inhibited the mutant SOD1-tubulin interaction in vitro. Binding mode analysis predicted that some inhibitors might bind the tubulin binding site of G85R SOD1 by pi electron interaction with the aromatic ring of the Trp32 residue of G85R SOD1. Our screening methods may contribute to the identification of lead compounds for treating ALS.


Asunto(s)
Mutación/fisiología , Superóxido Dismutasa-1/química , Superóxido Dismutasa-1/metabolismo , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Animales , Células COS , Chlorocebus aethiops , Evaluación Preclínica de Medicamentos/métodos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/metabolismo , Inhibidores Enzimáticos/farmacología , Humanos , Mutación/efectos de los fármacos , Unión Proteica/fisiología , Estructura Secundaria de Proteína , Superóxido Dismutasa-1/antagonistas & inhibidores , Superóxido Dismutasa-1/genética , Tubulina (Proteína)/genética
2.
PLoS Comput Biol ; 15(2): e1006800, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30817762

RESUMEN

Pollen provides an excellent system to study pattern formation at the single-cell level. Pollen surface is covered by the pollen wall exine, whose deposition is excluded from certain surface areas, the apertures, which vary between the species in their numbers, positions, and morphology. What determines aperture patterns is not understood. Arabidopsis thaliana normally develops three apertures, equally spaced along the pollen equator. However, Arabidopsis mutants whose pollen has higher ploidy and larger volume develop four or more apertures. To explore possible mechanisms responsible for aperture patterning, we developed a mathematical model based on the Gierer-Meinhardt system of equations. This model was able to recapitulate aperture patterns observed in the wild-type and higher-ploidy pollen. We then used this model to further explore geometric and kinetic factors that may influence aperture patterns and found that pollen size, as well as certain kinetic parameters, like diffusion and decay of morphogens, could play a role in formation of aperture patterns. In conjunction with mathematical modeling, we also performed a forward genetic screen in Arabidopsis and discovered two mutants with aperture patterns that had not been previously observed in this species but were predicted by our model. The macaron mutant develops a single ring-like aperture, matching the unusual ring-like pattern produced by the model. The doughnut mutant forms two pore-like apertures at the poles of the pollen grain. Further tests on these novel mutants, motivated by the modeling results, suggested the existence of an area of inhibition around apertures that prevents formation of additional apertures in their vicinity. This work demonstrates the ability of the theoretical model to help focus experimental efforts and to provide fundamental insights into an important biological process.


Asunto(s)
Arabidopsis , Modelos Biológicos , Morfogénesis , Mutación , Polen , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Arabidopsis/fisiología , Biología Computacional , Simulación por Computador , Cinética , Morfogénesis/genética , Morfogénesis/fisiología , Mutación/genética , Mutación/fisiología , Polen/genética , Polen/crecimiento & desarrollo , Polen/fisiología
3.
Neuroscience ; 386: 91-107, 2018 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-29949744

RESUMEN

The Na+/K+/Cl- cotransporter-1 (NKCC1) and the K+/Cl- cotransporter-2 (KCC2) set the transmembrane Cl- gradient in the brain, and are implicated in epileptogenesis. We studied the postnatal distribution of NKCC1 and KCC2 in wild-type (WT) mice, and in a mouse model of sleep-related epilepsy, carrying the mutant ß2-V287L subunit of the nicotinic acetylcholine receptor (nAChR). In WT neocortex, immunohistochemistry showed a wide distribution of NKCC1 in neurons and astrocytes. At birth, KCC2 was localized in neuronal somata, whereas at subsequent stages it was mainly found in the somatodendritic compartment. The cotransporters' expression was quantified by densitometry in the transgenic strain. KCC2 expression increased during the first postnatal weeks, while the NKCC1 amount remained stable, after birth. In mice expressing ß2-V287L, the KCC2 amount in layer V of prefrontal cortex (PFC) was lower than in the control littermates at postnatal day 8 (P8), with no concomitant change in NKCC1. Consistently, the GABAergic excitatory to inhibitory switch was delayed in PFC layer V of mice carrying ß2-V287L. At P60, the amount of KCC2 was instead higher in mice bearing the transgene. Irrespective of genotype, NKCC1 and KCC2 were abundantly expressed in the neuropil of most thalamic nuclei since birth. However, KCC2 expression decreased by P60 in the reticular nucleus, and more so in mice expressing ß2-V287L. Therefore, a complex regulatory interplay occurs between heteromeric nAChRs and KCC2 in postnatal forebrain. The pathogenetic effect of ß2-V287L may depend on altered KCC2 amounts in PFC during synaptogenesis, as well as in mature thalamocortical circuits.


Asunto(s)
Epilepsia/metabolismo , Prosencéfalo/metabolismo , Receptores Nicotínicos/metabolismo , Sueño/fisiología , Miembro 2 de la Familia de Transportadores de Soluto 12/biosíntesis , Simportadores/biosíntesis , Animales , Animales Recién Nacidos , Epilepsia/genética , Femenino , Expresión Génica , Masculino , Ratones , Ratones Transgénicos , Mutación/fisiología , Neocórtex/metabolismo , Subunidades de Proteína/genética , Subunidades de Proteína/metabolismo , Receptores Nicotínicos/genética , Miembro 2 de la Familia de Transportadores de Soluto 12/genética , Simportadores/genética , Tálamo/metabolismo , Cotransportadores de K Cl
4.
Muscle Nerve ; 56(3): 479-485, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-27935074

RESUMEN

INTRODUCTION: c.250G>A (p.Ala84Thr) in ETFDH is the most common mutation that causes later-onset multiple acyl-coenzyme A dehydrogenase deficiency (MADD) in the southern Chinese population. No functional study has targeted this mutation. METHODS: Using cells expressing ETFDH-wild-type (WT) or ETFDH-mutant (p.Ala84Thr), reactive oxygen species (ROS) production and neurite length were analyzed, followed by pathomechanism exploration and drug screening. RESULTS: Increased ROS production and marked neurite shortening were observed in the cells expressing the ETFDH-mutant, compared with WT. Further studies demonstrated that suberic acid, an accumulated intermediate metabolite in MADD, could significantly impair neurite outgrowth of NSC34 cells, but neurite shortening could be restored by supplementation with carnitine, riboflavin, or Coenzyme Q10. CONCLUSIONS: Neurite shortening caused by the c.250G>A mutation in ETFDH suggests that neural defects could be underdiagnosed in human patients with MADD. This impairment might be treatable with mitochondrial cofactor supplementation. Muscle Nerve 56: 479-485, 2017.


Asunto(s)
Flavoproteínas Transportadoras de Electrones/biosíntesis , Flavoproteínas Transportadoras de Electrones/genética , Proteínas Hierro-Azufre/biosíntesis , Proteínas Hierro-Azufre/genética , Mitocondrias/genética , Mitocondrias/metabolismo , Mutación/fisiología , Proyección Neuronal/fisiología , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/biosíntesis , Oxidorreductasas actuantes sobre Donantes de Grupo CH-NH/genética , Línea Celular , Humanos , Deficiencia Múltiple de Acil Coenzima A Deshidrogenasa/genética , Deficiencia Múltiple de Acil Coenzima A Deshidrogenasa/metabolismo , Neuritas/metabolismo , Proyección Neuronal/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Ubiquinona/análogos & derivados , Ubiquinona/farmacología
6.
J Gen Physiol ; 144(4): 311-20, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25225552

RESUMEN

Cystic fibrosis (CF), one of the most common lethal genetic diseases, is caused by loss-of-function mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes a chloride channel that, when phosphorylated, is gated by ATP. The third most common pathogenic mutation, a glycine-to-aspartate mutation at position 551 or G551D, shows a significantly decreased open probability (Po) caused by failure of the mutant channel to respond to ATP. Recently, a CFTR-targeted drug, VX-770 (Ivacaftor), which potentiates G551D-CFTR function in vitro by boosting its Po, has been approved by the FDA to treat CF patients carrying this mutation. Here, we show that, in the presence of VX-770, G551D-CFTR becomes responsive to ATP, albeit with an unusual time course. In marked contrast to wild-type channels, which are stimulated by ATP, sudden removal of ATP in excised inside-out patches elicits an initial increase in macroscopic G551D-CFTR current followed by a slow decrease. Furthermore, decreasing [ATP] from 2 mM to 20 µM resulted in a paradoxical increase in G551D-CFTR current. These results suggest that the two ATP-binding sites in the G551D mutant mediate opposite effects on channel gating. We introduced mutations that specifically alter ATP-binding affinity in either nucleotide-binding domain (NBD1 or NBD2) into the G551D background and determined that this disease-associated mutation converts site 2, formed by the head subdomain of NBD2 and the tail subdomain of NBD1, into an inhibitory site, whereas site 1 remains stimulatory. G551E, but not G551K or G551S, exhibits a similar phenotype, indicating that electrostatic repulsion between the negatively charged side chain of aspartate and the γ-phosphate of ATP accounts for the observed mutational effects. Understanding the molecular mechanism of this gating defect lays a foundation for rational drug design for the treatment of CF.


Asunto(s)
Adenosina Trifosfato/metabolismo , Adenosina Trifosfato/farmacología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/antagonistas & inhibidores , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Sustitución de Aminoácidos , Animales , Células CHO , Cricetinae , Cricetulus , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , ADN Complementario/genética , Ligandos , Modelos Moleculares , Mutación/fisiología , Técnicas de Placa-Clamp , Conformación Proteica
7.
Antimicrob Agents Chemother ; 58(7): 3626-35, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24733467

RESUMEN

Candidemia is the fourth most common kind of microbial bloodstream infection, with Candida albicans being the most common causative species. Echinocandins are employed as the first-line treatment for invasive candidiasis until the fungal species is determined and confirmed by clinical diagnosis. Echinocandins block the FKS glucan synthases responsible for embedding ß-(1,3)-d-glucan in the cell wall. The increasing use of these drugs has led to the emergence of antifungal resistance, and elevated MICs have been associated with single-residue substitutions in specific hot spot regions of FKS1 and FKS2. Here, we show for the first time the caspofungin-mediated in vivo selection of a double mutation within one allele of the FKS1 hot spot 1 in a clinical isolate. We created a set of isogenic mutants and used a hematogenous murine model to evaluate the in vivo outcomes of echinocandin treatment. Heterozygous and homozygous double mutations significantly enhance the in vivo resistance of C. albicans compared with the resistance seen with heterozygous single mutations. The various FKS1 hot spot mutations differ in the degree of their MIC increase, substance-dependent in vivo response, and impact on virulence. Our results demonstrate that echinocandin EUCAST breakpoint definitions correlate with the in vivo response when a standard dosing regimen is used but cannot predict the in vivo response after a dose escalation. Moreover, patients colonized by a C. albicans strain with multiple mutations in FKS1 have a higher risk for therapeutic failure.


Asunto(s)
Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Candida albicans/genética , Candidemia/tratamiento farmacológico , Candidemia/microbiología , Farmacorresistencia Fúngica/genética , Equinocandinas/farmacología , Equinocandinas/uso terapéutico , Proteínas Fúngicas/genética , Glucosiltransferasas/genética , Mutación/genética , Mutación/fisiología , Adulto , Animales , Candida albicans/metabolismo , Quitina/metabolismo , Dermatoglifia del ADN , Femenino , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Polimorfismo de Nucleótido Simple/genética , Virulencia/genética
8.
Antimicrob Agents Chemother ; 58(7): 3646-9, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24733474

RESUMEN

It has been argued that the in vitro activity of caspofungin (CSP) is not a good predictor of the outcome of echinocandin treatment in vivo. We evaluated the in vitro activity of CSP and the presence of FKS mutations in the hot spot 1 (HS1) region of the FKS1 and FKS2 genes in 17 Candida glabrata strains with a wide range of MICs. The efficacy of CSP against systemic infections from each of the 17 strains was evaluated in a murine model. No HS1 mutations were found in the eight strains showing MICs for CSP of ≤ 0.5 µg/ml, but they were present in eight of the nine strains with MICs of ≥ 1 µg/ml, i.e., three in the FKS1 gene and five in the FKS2 gene. CSP was effective for treating mice infected with strains with MICs of ≤ 0.5 µg/ml, showed variable efficacy in animals challenged with strains with MICs of 1 µg/ml, and did not work in those with strains with MICs of >1 µg/ml. In addition, mutations, including one reported for the first time, were found outside the HS1 region in the FKS2 gene of six strains with different MICs, but their presence did not influence drug efficacy. The in vitro activity of CSP was compared with that of another echinocandin, anidulafungin, suggesting that the MICs of both drugs, as well as mutations in the HS1 regions of the FKS1 and FKS2 genes, are predictive of outcome.


Asunto(s)
Antifúngicos/farmacología , Candida glabrata/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Equinocandinas/farmacología , Proteínas Fúngicas/genética , Glucosiltransferasas/genética , Mutación/fisiología , Animales , Candida glabrata/genética , Candidiasis/microbiología , Caspofungina , Farmacorresistencia Fúngica/genética , Riñón/microbiología , Lipopéptidos , Masculino , Ratones , Pruebas de Sensibilidad Microbiana , Tasa de Supervivencia
9.
Pflugers Arch ; 466(4): 719-34, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24519464

RESUMEN

Absence epilepsy accompanies the paroxysmal oscillations in the thalamocortical circuit referred as spike and wave discharges (SWDs). Low-threshold burst firing mediated by T-type Ca(2+) channels highly expressed in both inhibitory thalamic reticular nuclei (TRN) and excitatory thalamocortical (TC) neurons has been correlated with the generation of SWDs. A generally accepted view has been that rhythmic burst firing mediated by T-type channels in both TRN and TC neurons are equally critical in the generation of thalamocortical oscillations during sleep rhythms and SWDs. This review examined recent studies on the T-type channels in absence epilepsy which leads to an idea that even though both TRN and TC nuclei are required for thalamocortical oscillations, the contributions of T-type channels to TRN and TC neurons are not equal in the genesis of sleep spindles and SWDs. Accumulating evidence revealed a crucial role of TC T-type channels in SWD generation. However, the role of TRN T-type channels in SWD generation remains controversial. Therefore, a deeper understanding of the functional consequences of modulating each T-type channel subtype could guide the development of therapeutic tools for absence seizures while minimizing side effects on physiological thalamocortical oscillations.


Asunto(s)
Potenciales de Acción/fisiología , Canales de Calcio Tipo T/fisiología , Epilepsia Tipo Ausencia/fisiopatología , Tálamo/fisiopatología , Animales , Electroencefalografía/tendencias , Epilepsia Tipo Ausencia/diagnóstico , Epilepsia Tipo Ausencia/genética , Humanos , Mutación/fisiología
10.
J Neurosci ; 33(26): 10661-6, 2013 Jun 26.
Artículo en Inglés | MEDLINE | ID: mdl-23804089

RESUMEN

Hearing over a wide range of sound intensities is thought to require complementary coding by functionally diverse spiral ganglion neurons (SGNs), each changing activity only over a subrange. The foundations of SGN diversity are not well understood but likely include differences among their inputs: the presynaptic active zones (AZs) of inner hair cells (IHCs). Here we studied one candidate mechanism for causing SGN diversity-heterogeneity of Ca(2+) influx among the AZs of IHCs-during postnatal development of the mouse cochlea. Ca(2+) imaging revealed a change from regenerative to graded synaptic Ca(2+) signaling after the onset of hearing, when in vivo SGN spike timing changed from patterned to Poissonian. Furthermore, we detected the concurrent emergence of stronger synaptic Ca(2+) signals in IHCs and higher spontaneous spike rates in SGNs. The strengthening of Ca(2+) signaling at a subset of AZs primarily reflected a gain of Ca(2+) channels. We hypothesize that the number of Ca(2+) channels at each IHC AZ critically determines the firing properties of its corresponding SGN and propose that AZ heterogeneity enables IHCs to decompose auditory information into functionally diverse SGNs.


Asunto(s)
Señalización del Calcio/fisiología , Calcio/metabolismo , Nervio Coclear/fisiología , Células Ciliadas Auditivas Internas/fisiología , Audición/fisiología , Animales , Canales de Calcio/fisiología , Cóclea/crecimiento & desarrollo , Cóclea/inervación , Nervio Coclear/crecimiento & desarrollo , Núcleo Coclear/citología , Núcleo Coclear/fisiología , Simulación por Computador , Fenómenos Electrofisiológicos , Femenino , Inmunohistoquímica , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía Confocal , Modelos Neurológicos , Mutación/fisiología , Proteínas del Tejido Nervioso/genética , Técnicas de Placa-Clamp , Receptores Presinapticos/fisiología , Ganglio Espiral de la Cóclea/citología , Ganglio Espiral de la Cóclea/crecimiento & desarrollo , Ganglio Espiral de la Cóclea/fisiología , Fracciones Subcelulares/fisiología
11.
J Neurosci ; 33(25): 10459-70, 2013 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-23785158

RESUMEN

Regulation of sexual reproduction and energy homeostasis are closely interconnected, but only few efforts were made to explore the impact of gonadotropic neurons on metabolic processes. We have used Nscl-2 mutant mice suffering from adult onset of obesity and hypogonadotropic hypogonadism to study effects of gonadotropin releasing hormone (GnRH) neurons on neuronal circuits controlling energy balance. Inactivation of Nscl-2 in GnRH neurons but not in pro-opiomelanocortin (POMC) neurons reduced POMC neurons and increased visceral fat mass, suggesting a critical role of GnRH cells in the regulation of POMC neurons. In contrast, absence of POMC processing in the majority of Nscl-2-deficient POMC neurons had no effect on energy homeostasis. Finally, we investigated the cellular basis of the reduction of GnRH neurons in NSCL-2 mutants using a lineage tracing approach. We found that loss of Nscl-2 results in aberrant migration of GnRH neurons in Nscl-2 mutant mice causing a lineage switch of ectopically located GnRH neurons.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/fisiología , Hormona Liberadora de Gonadotropina/genética , Hormona Liberadora de Gonadotropina/fisiología , Hipotálamo/fisiología , Neuronas/fisiología , Obesidad/genética , Proopiomelanocortina/fisiología , Tejido Adiposo/crecimiento & desarrollo , Tejido Adiposo/fisiología , Hormona Adrenocorticotrópica/metabolismo , Hormona Adrenocorticotrópica/fisiología , Animales , Western Blotting , División Celular/fisiología , Estradiol/sangre , Femenino , Homeostasis/genética , Homeostasis/fisiología , Hipotálamo Posterior/fisiología , Infertilidad/genética , Ratones , Ratones Noqueados , Mutación/genética , Mutación/fisiología , Área Preóptica/fisiología , Proopiomelanocortina/biosíntesis , Proopiomelanocortina/genética , Reproducción/genética , Reproducción/fisiología
12.
J Neurol Sci ; 330(1-2): 45-51, 2013 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-23639391

RESUMEN

BACKGROUND: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebral small vessel disease, clinically characterized by migraine, recurrent transient ischemic attacks or strokes, psychiatric disorders and cognitive decline. Strokes are typically ischemic, while hemorrhagic events have been only sporadically described. However, cerebral microbleeds have been found in 31-69% of CADASIL patients. METHODS: We describe four unrelated CADASIL patients who had hemorrhagic strokes. We also briefly review the literature on intracerebral hemorrhage (ICH) in CADASIL. RESULTS: Three patients had a thalamo-capsular hemorrhage (age at onset: 54, 67, 77) and one of these had a second hemispheric cerebellar hemorrhage. Another patient experienced an interpeduncular cistern subarachnoid hemorrhage when he was 39. None of these patients was receiving antiplatelets, anticoagulants or statins at the time of hemorrhage; all were hypertensive. NOTCH3 gene analysis revealed mutations on exons 14, 22 (two patients presenting the same mutation), and 24. MRI signs of previous hemorrhages were present in all these patients. CONCLUSIONS: Hemorrhagic stroke can occur in CADASIL similarly to sporadic cerebral small vessel diseases; this finding expands the phenotype of the disease. A diagnosis of CADASIL should probably be considered also in patients with ICH. These data bear potential implications in terms of need of better control of risk factors, particularly hypertension, and raise relevant questions about the use of antiplatelets as prevention measures in CADASIL patients.


Asunto(s)
CADASIL/complicaciones , Hemorragias Intracraneales/etiología , Adulto , Anciano , CADASIL/genética , Femenino , Hemiplejía/etiología , Humanos , Cápsula Interna/patología , Hemorragias Intracraneales/genética , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Mutación/genética , Mutación/fisiología , Receptor Notch3 , Receptores Notch/genética , Accidente Cerebrovascular/etiología , Hemorragia Subaracnoidea/etiología , Tálamo/patología , Tomografía Computarizada por Rayos X
13.
Anesthesiology ; 119(1): 111-8, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23459219

RESUMEN

BACKGROUND: Mutations within the gene encoding the skeletal muscle calcium channel ryanodine receptor can result in malignant hyperthermia. Although it is important to characterize the functional effects of candidate mutations to establish a genetic test for diagnosis, ex vivo methods are limited because of the low incidence of the disorder and sample unavailability. More than 250 candidate mutations have been identified, but only a few mutations have been functionally characterized. METHODS: The human skeletal muscle ryanodine receptor complementary DNA was cloned with or without a disease-related variant. Wild-type and mutant calcium channel proteins were transiently expressed in human embryonic kidney-293 cells expressing the large T-antigen of simian virus 40, and functional analysis was carried out using calcium imaging with fura-2 AM. Six human malignant hyperthermia-related mutants such as R44C, R163C, R401C, R533C, R533H, and H4833Y were analyzed. Cells were stimulated with a specific ryanodine receptor agonist 4-chloro-m-cresol, and intracellular calcium mobility was analyzed to determine the functional aspects of mutant channels. RESULTS: Mutant proteins that contained a variant linked to malignant hyperthermia showed higher sensitivity to the agonist. Compared with the wild type (EC50=453.2 µM, n=18), all six mutants showed a lower EC50 (21.2-170.4 µM, n=12-23), indicating susceptibility against triggering agents. CONCLUSIONS: These six mutations cause functional abnormality of the calcium channel, leading to higher sensitivity to a specific agonist, and therefore could be considered potentially causative of malignant hyperthermia reactions.


Asunto(s)
Hipertermia Maligna/genética , Mutación/genética , Canal Liberador de Calcio Receptor de Rianodina/efectos de los fármacos , Canal Liberador de Calcio Receptor de Rianodina/genética , Calcio/metabolismo , ADN Complementario/genética , ADN Complementario/metabolismo , Técnica del Anticuerpo Fluorescente , Células HEK293 , Humanos , Hipertermia Maligna/fisiopatología , Mutación/fisiología , Neuroimagen , Canal Liberador de Calcio Receptor de Rianodina/fisiología
14.
Neuroscience ; 235: 119-28, 2013 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-23333676

RESUMEN

Iron abnormalities within the brain are associated with several rare but severe neurodegenerative conditions. There is growing evidence that more common systemic iron loading disorders such as hemochromatosis can also have important effects on the brain. To identify features that are common across different forms of hemochromatosis, we used microarray and real-time reverse transcription polymerase chain reaction (RT-PCR) to assess brain transcriptome profiles of transferrin receptor 2 mutant mice (Tfr2(mut)), a model of a rare type of hereditary hemochromatosis, relative to wildtype control mice. The results were compared with our previous findings in dietary iron-supplemented wildtype mice and Hfe(-/-) mice, a model of a common type of hereditary hemochromatosis. For transcripts showing significant changes relative to controls across all three models, there was perfect (100%) directional concordance (i.e. transcripts were increased in all models or decreased in all models). Comparison of the two models of hereditary hemochromatosis, which showed more pronounced changes than the dietary iron-supplemented mice, revealed numerous common molecular effects. Pathway analyses highlighted changes for genes relating to long-term depression (6.8-fold enrichment, p=5.4×10(-7)) and, to a lesser extent, long-term potentiation (3.7-fold enrichment, p=0.01), with generalized reductions in transcription of key genes from these pathways, which are involved in modulating synaptic strength and efficacy and are essential for memory and learning. The agreement across the models suggests the findings are robust and strengthens previous evidence that iron loading disorders affect the brain. Perturbations of brain phenomena such as long-term depression and long-term potentiation might partly explain neurologic symptoms reported for some hemochromatosis patients.


Asunto(s)
Química Encefálica/genética , Química Encefálica/fisiología , Hemocromatosis/genética , Hemocromatosis/patología , Hierro/toxicidad , Potenciación a Largo Plazo/fisiología , Plasticidad Neuronal/fisiología , Receptores de Transferrina/genética , Receptores de Transferrina/fisiología , Transcriptoma/genética , Animales , Western Blotting , Ferritinas/metabolismo , Glioma/metabolismo , Glioma/patología , Proteína de la Hemocromatosis , Antígenos de Histocompatibilidad Clase I/genética , Antígenos de Histocompatibilidad Clase I/fisiología , Hierro de la Dieta/farmacología , Hígado/metabolismo , Proteínas de la Membrana/genética , Proteínas de la Membrana/fisiología , Ratones , Ratones Noqueados , Análisis por Micromatrices , Mutación/genética , Mutación/fisiología , Mutación Missense/genética , Mutación Missense/fisiología , Reacción en Cadena en Tiempo Real de la Polimerasa , Espectrofotometría Atómica
15.
Int J Gynecol Cancer ; 22(9): 1517-26, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23060048

RESUMEN

OBJECTIVE: The fibroblast growth factor (FGF) family of signaling molecules has been associated with chemoresistance and poor prognosis in a number of cancer types, including lung, breast, ovarian, prostate, and head and neck carcinomas. Given the identification of activating mutations in the FGF receptor 2 (FGFR2) receptor tyrosine kinase in a subset of endometrial tumors, agents with activity against FGFRs are currently being tested in clinical trials for recurrent and progressive endometrial cancer. Here, we evaluated the effect of FGFR inhibition on the in vitro efficacy of chemotherapy in endometrial cancer cell lines. METHODS: Human endometrial cancer cell lines with wild-type or activating FGFR2 mutations were used to determine any synergism with concurrent use of the pan-FGFR inhibitor, PD173074, and the chemotherapeutics, doxorubicin and paclitaxel, on cell proliferation and apoptosis. RESULTS: FGFR2 mutation status did not alter sensitivity to either chemotherapeutic agent alone. The combination of PD173074 with paclitaxel or doxorubicin showed synergistic activity in the 3 FGFR2 mutant cell lines evaluated. In addition, although nonmutant cell lines were resistant to FGFR inhibition alone, the addition of PD173074 potentiated the cytostatic effect of paclitaxel and doxorubicin in a subset of FGFR2 wild-type endometrial cancer cell lines. CONCLUSIONS: Together these data suggest a potential therapeutic benefit to combining an FGFR inhibitor with standard chemotherapeutic agents in endometrial cancer therapy particularly in patients with FGFR2 mutation positive tumors.


Asunto(s)
Carcinoma Endometrioide/patología , Doxorrubicina/farmacología , Neoplasias Endometriales/patología , Paclitaxel/farmacología , Pirimidinas/farmacología , Receptores de Factores de Crecimiento de Fibroblastos/antagonistas & inhibidores , Antineoplásicos/administración & dosificación , Antineoplásicos/farmacología , Carcinoma Endometrioide/tratamiento farmacológico , Carcinoma Endometrioide/genética , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Doxorrubicina/administración & dosificación , Evaluación Preclínica de Medicamentos , Resistencia a Antineoplásicos/efectos de los fármacos , Resistencia a Antineoplásicos/genética , Sinergismo Farmacológico , Neoplasias Endometriales/tratamiento farmacológico , Neoplasias Endometriales/genética , Femenino , Humanos , Mutación/fisiología , Paclitaxel/administración & dosificación , Pirimidinas/administración & dosificación , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 2 de Factor de Crecimiento de Fibroblastos/metabolismo , Receptores de Factores de Crecimiento de Fibroblastos/genética , Células Tumorales Cultivadas
16.
J Clin Endocrinol Metab ; 97(9): E1791-7, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22745233

RESUMEN

CONTEXT: Mutations within the PROP1 gene represent one of the main causes of familial combined pituitary hormone deficiency (CPHD). However, most of the cases are sporadic with an unknown genetic cause. OBJECTIVE: The aim of this study was the search for low penetrance variations within and around a conserved regulatory element in the intron 1 of PROP1, contributing to a multifactorial form of the disease in sporadic patients. METHODS AND PATIENTS: A fragment of 570 bp encompassing the conserved region was sequenced in 107 CPHD patients and 294 controls, and an association study was performed with the four identified variants, namely c.109+435G>A (rs73346254), c.109+463C>T (rs4498267), c.109+768C>G (rs4431364), and c.109+915_917ins/delTAG (rs148607624). The functional role of the associated polymorphisms was evaluated by luciferase reporter gene expression analyses and EMSA. RESULTS: A statistically significant increased frequency was observed in the patients for rs73346254A (P = 5 × 10(-4)) and rs148607624delTAG (P = 0.01) alleles. Among all the possible allele combinations, only the haplotype bearing both risk alleles showed a significantly higher frequency in the patients vs. controls (P = 4.7 × 10(-4)) and conferred a carrier risk of 4.19 (P = 1.2 × 10(-4)). This haplotype determined a significant decrease of the luciferase activity in comparison with a basal promoter and the other allelic combinations in GH4C and MCF7 cells (P = 4.6 × 10(-6); P = 5.5 × 10(-4), respectively). The EMSA showed a differential affinity for nuclear proteins for the alternative alleles of the two associated variations. CONCLUSIONS: Variations with a functional significance conferring susceptibility to CPHD have been identified in the PROP1 gene, indicating a multifactorial origin of this disorder in sporadic cases.


Asunto(s)
Proteínas de Homeodominio/genética , Hormona de Crecimiento Humana/deficiencia , Adolescente , Edad de Inicio , Células Cultivadas , Niño , Preescolar , Secuencia Conservada , Ensayo de Cambio de Movilidad Electroforética , Femenino , Variación Genética , Vectores Genéticos , Hormonas/sangre , Humanos , Hipotálamo/patología , Lactante , Factor I del Crecimiento Similar a la Insulina/deficiencia , Intrones/genética , Luciferasas/genética , Imagen por Resonancia Magnética , Masculino , Mutación/genética , Mutación/fisiología , Penetrancia , Hipófisis/patología , Hormonas Hipofisarias/sangre , Polimorfismo de Nucleótido Simple/genética , Transfección , Adulto Joven
19.
Int J Med Sci ; 9(2): 148-56, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22253562

RESUMEN

OBJECTIVE: To establish a rapid detection method for identifying rpoB mutations associated with rifampin (RIF) resistance in sputum specimens. METHODS: We detected rpoB mutations directly in 90 sputum specimens collected from suspected tuberculosis patients using PCR-based denaturing gradient gel electrophoresis (DGGE) and compared these results with those obtained by rpoB sequencing and conventional drug susceptibility testing. RESULTS: The positive detection rate of Mycobacterium tuberculosis (M. tuberculosis) was 52.2% by Acid-Fast Bacilli staining and 72.2% by conventional mycobacterial culture. In contrast, the positive rate was significantly higher (93.3%) by PCR-based detection of the rpoB gene in the same specimens. Furthermore, 75% of the tested specimens presented abnormal patterns compared with the wild-type pattern (standard H37Rv strain) analysed by DGGE. A total of 12 different patterns, representing 12 different rpoB mutations, were observed in the 63 abnormal patterns. The match rate of rpoB mutations detected by DGGE reached 96.9% when compared to DNA sequencing. CONCLUSION: Our findings indicate that PCR-based DGGE is a rapid and reliable bio-technique for direct detection of rpoB mutations associated with RIF resistance in the sputum of suspected tuberculosis patients.


Asunto(s)
Proteínas Bacterianas/genética , Análisis Mutacional de ADN/métodos , Electroforesis en Gel de Gradiente Desnaturalizante/métodos , Farmacorresistencia Microbiana/genética , Mycobacterium tuberculosis/genética , Rifampin/uso terapéutico , Esputo/microbiología , Proteínas Bacterianas/análisis , ADN Bacteriano/genética , ADN Bacteriano/aislamiento & purificación , ARN Polimerasas Dirigidas por ADN , Humanos , Pruebas de Sensibilidad Microbiana , Mutación/fisiología , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Esputo/química , Esputo/metabolismo
20.
Cardiovasc Ther ; 30(5): e234-41, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21884024

RESUMEN

The aim of this review is to provide useful information not only for studying the effect of OATP1B1 and/or BCRP gene mutation on pharmacokinetics of novle statins of pitavastatin and rosuvastatin but also for studying drug-drug interactions (DDI) between the novle statins and other substrates of OATP1B1 and/or BCRP. Intra- and inter-ethnic differences in pharmacokinetic profiles of clinically relevant drugs are important issues reported in many papers not only for scenes of appropriate drug used in clinical settings but also for those of the drug development. Pharmacogenomics is extremely useful for understanding these racial differences. Recent pharmacogenetics study have disclosed important roles of drug transporters in the pharmacokinetic (PK) profiles of some clinically relevant drugs. In this presentation, we introduce single nucleotide polymorphisms (SNPs) of OATP1B1 and BCRP and review the contribution of genetic polymorphisms of the transporters to the pharmacokinetics of dual substrates as pitavastatin and rosuvastatin from recent study. At the same time, the DDIs between pitavastatin or rosuvastatin and other drug have been extensively concerned because of inhibiting OATP1B1-mediated hepatic uptake or BCRP-mediated hepatic efflux of pitavastatin and rosuvastatin. This review summarized the current studies about the role of OATP1B1 and BCRP in DDIs between pitavastatin or rosuvastatin and other clinically relevant drugs. The role of OATP1B1 and BCRP gene mutation can affect the PK profiles of pitavastatin and rosuvastatin. The DDIs between the novle statins and other substrates of OATP1B1 or BCRP may occur and cause change in the pharmacokinetic of the novle statins.


Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacocinética , Proteínas de Neoplasias/metabolismo , Transportadores de Anión Orgánico/metabolismo , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2 , Transportadoras de Casetes de Unión a ATP/genética , Animales , Antihipertensivos/efectos adversos , Interacciones Farmacológicas , Humanos , Transportador 1 de Anión Orgánico Específico del Hígado , Mutación/genética , Mutación/fisiología , Proteínas de Neoplasias/genética , Transportadores de Anión Orgánico/genética , Preparaciones de Plantas , Polimorfismo Genético/genética
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