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1.
Int J Nurs Pract ; 30(3): e13229, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38123157

RESUMEN

BACKGROUND: A skin tear is a traumatic wound that occurs in up to one in five hospitalized patients. Nursing care includes application of a dressing to create a moist wound healing environment. AIM: To compare the effectiveness of two standard dressings (adhesive silicone foam vs. meshed silicone interface) to heal hospital-acquired skin tear. METHODS: An intention-to-treat pilot study was designed using a randomized, non-inferiority trial in an Australian tertiary hospital setting. Consenting participants (n = 52) had acquired a skin tear within the previous 24 h and had agreed to a 3-week follow-up. Data were collected between 2014 and 2020. The primary outcome measure was wound healing at 21 days. RESULTS: Baseline characteristics were similar in both arms. Per protocol, 86% of skin tears were fully healed at 3 weeks in the adhesive silicone foam group, compared to 59% in the meshed silicone interface group. Greater healing was observed across all skin tear categories in the adhesive silicone foam dressing group. In the intention-to-treat sample, healing was 69% and 42%, respectively. CONCLUSIONS: Results suggest the adhesive silicone foam dressing may be superior, as it produced clinically significant healing of skin tears at 3 weeks compared to the meshed silicone interface dressing. Accounting for potential loss to follow-up, a sample of at least 103 participants per arm would be required to power a definitive study.


Asunto(s)
Vendajes , Siliconas , Cicatrización de Heridas , Humanos , Proyectos Piloto , Masculino , Femenino , Estudios Prospectivos , Persona de Mediana Edad , Piel/lesiones , Anciano , Adulto , Laceraciones/terapia
2.
Int Wound J ; 19(6): 1418-1427, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34951125

RESUMEN

Hospital-acquired skin tear prevalence is under-reported; thus, the aim of this study was to analyse skin tear point prevalence and characteristics in a tertiary acute care hospital in Queensland, Australia, over a 10-year period. All consenting adult inpatients received a full skin inspection and skin tear category, site, cause, treatment, and whether it was documented as hospital- or community-acquired were recorded. Eleven prevalence audits were analysed with a total sample of 3626 patients. An overall pooled prevalence of 8.9% (95% confidence interval [CI] 7.5-10.4) with an associated hospital-acquired pooled prevalence of 5.5% (95% CI 4.5-6.7) was found. In total, 616 skin tears were reported, of which 374 (60.7%) were hospital-acquired. Over a third of patients (38.7%) had multiple skin tears and most patients (84.8%) with at least one skin tear were aged ≥70 years. The largest proportion of skin tears (40.1%) was those with no skin flap. Of those documented, most were caused by falls or collisions, suggesting combined skin tear and falls prevention strategies may be effective. Over a decade, there was a downward trend in hospital-acquired skin tear, which is encouraging. Skin tear prevalence is recommended as a measure of care quality with an emphasis on good quality documentation.


Asunto(s)
Laceraciones , Traumatismos de los Tejidos Blandos , Adulto , Australia , Hospitales , Humanos , Pacientes Internos , Laceraciones/epidemiología , Prevalencia
3.
Neurobiol Dis ; 134: 104632, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31678406

RESUMEN

ARFGEF1 encodes a guanine exchange factor involved in intracellular vesicle trafficking, and is a candidate gene for childhood genetic epilepsies. To model ARFGEF1 haploinsufficiency observed in a recent Lennox Gastaut Syndrome patient, we studied a frameshift mutation (Arfgef1fs) in mice. Arfgef1fs/+ pups exhibit signs of developmental delay, and Arfgef1fs/+ adults have a significantly decreased threshold to induced seizures but do not experience spontaneous seizures. Histologically, the Arfgef1fs/+ brain exhibits a disruption in the apical lining of the dentate gyrus and altered spine morphology of deep layer neurons. In primary hippocampal neuron culture, dendritic surface and synaptic but not total GABAA receptors (GABAAR) are reduced in Arfgef1fs/+ neurons with an accompanying decrease in the number of GABAAR-containing recycling endosomes in cell body. Arfgef1fs/+ neurons also display differences in the relative ratio of Arf6+:Rab11+:TrfR+ recycling endosomes. Although the GABAAR-containing early endosomes in Arfgef1fs/+ neurons are comparable to wildtype, Arfgef1fs/+ neurons show an increase in the number of GABAAR-containing lysosomes in dendrite and cell body. Together, the altered endosome composition and decreased neuronal surface GABAAR results suggests a mechanism whereby impaired neuronal inhibition leads to seizure susceptibility.


Asunto(s)
Endosomas/metabolismo , Factores de Intercambio de Guanina Nucleótido/metabolismo , Neuronas/metabolismo , Receptores de GABA-A/metabolismo , Convulsiones/metabolismo , Animales , Encéfalo/metabolismo , Preescolar , Factores de Intercambio de Guanina Nucleótido/genética , Haploinsuficiencia , Humanos , Lactante , Síndrome de Lennox-Gastaut/genética , Masculino , Proteínas de la Membrana , Ratones , Ratones Noqueados
4.
Mol Ther ; 27(1): 87-101, 2019 01 02.
Artículo en Inglés | MEDLINE | ID: mdl-30446391

RESUMEN

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease selectively targeting motor neurons in the brain and spinal cord. The reasons for differential motor neuron susceptibility remain elusive. We developed a stem cell-based motor neuron assay to study cell-autonomous mechanisms causing motor neuron degeneration, with implications for ALS. A small-molecule screen identified cyclopiazonic acid (CPA) as a stressor to which stem cell-derived motor neurons were more sensitive than interneurons. CPA induced endoplasmic reticulum stress and the unfolded protein response. Furthermore, CPA resulted in an accelerated degeneration of motor neurons expressing human superoxide dismutase 1 (hSOD1) carrying the ALS-causing G93A mutation, compared to motor neurons expressing wild-type hSOD1. A secondary screen identified compounds that alleviated CPA-mediated motor neuron degeneration: three kinase inhibitors and tauroursodeoxycholic acid (TUDCA), a bile acid derivative. The neuroprotective effects of these compounds were validated in human stem cell-derived motor neurons carrying a mutated SOD1 allele (hSOD1A4V). Moreover, we found that the administration of TUDCA in an hSOD1G93A mouse model of ALS reduced muscle denervation. Jointly, these results provide insights into the mechanisms contributing to the preferential susceptibility of ALS motor neurons, and they demonstrate the utility of stem cell-derived motor neurons for the discovery of new neuroprotective compounds.


Asunto(s)
Neuronas Motoras/citología , Células Madre/metabolismo , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Estrés del Retículo Endoplásmico/efectos de los fármacos , Estrés del Retículo Endoplásmico/genética , Humanos , Indoles/farmacología , Ratones , Neuronas Motoras/efectos de los fármacos , Neuronas Motoras/metabolismo , Mutación , Células Madre/efectos de los fármacos , Superóxido Dismutasa-1/genética , Superóxido Dismutasa-1/metabolismo , Ácido Tauroquenodesoxicólico/farmacología
6.
Int Wound J ; 15(4): 527-533, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29797534

RESUMEN

Skin tears cause pain, increased length of stay, increased costs, and reduced quality of life. Minimal research reports the association between skin tears, and malnutrition using robust measures of nutritional status. This study aimed to articulate the association between malnutrition and skin tears in hospital inpatients using a yearly point prevalence of inpatients included in the Queensland Patient Safety Bedside Audit, malnutrition audits and skin tear audits conducted at a metropolitan tertiary hospital between 2010 and 2015. Patients were excluded if admitted to mental health wards or were <18 years. A total of 2197 inpatients were included, with a median age of 71 years. The overall prevalence of skin tears was 8.1%. Malnutrition prevalence was 33.5%. Univariate analysis demonstrated associations between age (P ˂ .001), body mass index (BMI) (P < .001) and malnutrition (P ˂ .001) but not gender (P = .319). Binomial logistic regression analysis modelling demonstrated that malnutrition diagnosed using the Subjective Global Assessment was independently associated with skin tear incidence (odds ratio, OR: 1.63; 95% confidence interval, CI: 1.13-2.36) and multiple skin tears (OR 2.48 [95% CI 1.37-4.50]). BMI was not independently associated with skin tears or multiple skin tears. This study demonstrated independent associations between malnutrition and skin tear prevalence and multiple skin tears. It also demonstrated the limitations of BMI as a nutritional assessment measure.


Asunto(s)
Laceraciones/etiología , Laceraciones/fisiopatología , Desnutrición/complicaciones , Desnutrición/fisiopatología , Adulto , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Pacientes Internos/estadística & datos numéricos , Laceraciones/epidemiología , Masculino , Desnutrición/epidemiología , Persona de Mediana Edad , Estado Nutricional , Oportunidad Relativa , Prevalencia , Queensland/epidemiología , Adulto Joven
7.
J Neurosci ; 36(48): 12243-12258, 2016 11 30.
Artículo en Inglés | MEDLINE | ID: mdl-27903732

RESUMEN

Mutations in the gene encoding Parkin, an E3 ubiquitin ligase, lead to juvenile-onset Parkinson's disease by inducing the selective death of midbrain dopaminergic neurons. Accumulating evidence indicates that Parkin also has an important role in excitatory glutamatergic neurotransmission, although its precise mechanism of action remains unclear. Here, we investigate Parkin's role at glutamatergic synapses of rat hippocampal neurons. We find that Parkin-deficient neurons exhibit significantly reduced AMPA receptor (AMPAR)-mediated currents and cell-surface expression, and that these phenotypes result from decreased postsynaptic expression of the adaptor protein Homer1, which is necessary for coupling AMPAR endocytic zones with the postsynaptic density. Accordingly, Parkin loss of function leads to the reduced density of postsynaptic endocytic zones and to impaired AMPAR internalization. These findings demonstrate a novel and essential role for Parkin in glutamatergic neurotransmission, as a stabilizer of postsynaptic Homer1 and the Homer1-linked endocytic machinery necessary for maintaining normal cell-surface AMPAR levels. SIGNIFICANCE STATEMENT: Mutations in Parkin, a ubiquitinating enzyme, lead to the selective loss of midbrain dopaminergic neurons and juvenile-onset Parkinson's disease (PD). Parkin loss of function has also been shown to alter hippocampal glutamatergic neurotransmission, providing a potential explanation for PD-associated cognitive impairment. However, very little is known about Parkin's specific sites or mechanisms of action at glutamatergic synapses. Here, we show that Parkin deficiency leads to decreased AMPA receptor-mediated activity due to disruption of the postsynaptic endocytic zones required for maintaining proper cell-surface AMPA receptor levels. These findings demonstrate a novel role for Parkin in synaptic AMPA receptor internalization and suggest a Parkin-dependent mechanism for hippocampal dysfunction that may explain cognitive deficits associated with some forms of PD.


Asunto(s)
Endocitosis/fisiología , Ácido Glutámico/metabolismo , Neuronas/fisiología , Receptores AMPA/metabolismo , Transmisión Sináptica/fisiología , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Femenino , Masculino , Inhibición Neural/fisiología , Neurotransmisores/metabolismo , Ratas , Ratas Sprague-Dawley , Ratas Transgénicas , Ubiquitina-Proteína Ligasas/genética
8.
J Neurosci ; 33(2): 574-86, 2013 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-23303937

RESUMEN

Human pluripotent stem cells are a promising source of differentiated cells for developmental studies, cell transplantation, disease modeling, and drug testing. However, their widespread use even for intensely studied cell types like spinal motor neurons is hindered by the long duration and low yields of existing protocols for in vitro differentiation and by the molecular heterogeneity of the populations generated. We report a combination of small molecules that within 3 weeks induce motor neurons at up to 50% abundance and with defined subtype identities of relevance to neurodegenerative disease. Despite their accelerated differentiation, motor neurons expressed combinations of HB9, ISL1, and column-specific markers that mirror those observed in vivo in human embryonic spinal cord. They also exhibited spontaneous and induced activity, and projected axons toward muscles when grafted into developing chick spinal cord. Strikingly, this novel protocol preferentially generates motor neurons expressing markers of limb-innervating lateral motor column motor neurons (FOXP1(+)/LHX3(-)). Access to high-yield cultures of human limb-innervating motor neuron subtypes will facilitate in-depth study of motor neuron subtype-specific properties, disease modeling, and development of large-scale cell-based screening assays.


Asunto(s)
Extremidades/inervación , Neuronas Motoras/fisiología , Células-Madre Neurales/fisiología , Animales , Axones/fisiología , Calcio/fisiología , Señalización del Calcio/fisiología , Diferenciación Celular/fisiología , Células Cultivadas , Embrión de Pollo , ADN Complementario/biosíntesis , ADN Complementario/genética , Femenino , Factores de Transcripción Forkhead/biosíntesis , Factores de Transcripción Forkhead/genética , Proteínas de Homeodominio/genética , Humanos , Inmunohistoquímica , Proteínas con Homeodominio LIM/genética , Masculino , Ratones , Neuronas Motoras/metabolismo , Células-Madre Neurales/metabolismo , Técnicas de Placa-Clamp , Complejo Silenciador Inducido por ARN , Proteínas Represoras/biosíntesis , Proteínas Represoras/genética , Médula Espinal/citología , Médula Espinal/embriología , Trasplante de Células Madre/métodos , Factores de Transcripción/genética
9.
Cell Chem Biol ; 31(7): 1324-1335.e20, 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-38729162

RESUMEN

The ability to optically stimulate and inhibit neurons has revolutionized neuroscience research. Here, we present a direct, potent, user-friendly chemical approach for optically silencing neurons. We have rendered saxitoxin (STX), a naturally occurring paralytic agent, transiently inert through chemical protection with a previously undisclosed nitrobenzyl-derived photocleavable group. Exposing the caged toxin, STX-bpc, to a brief (5 ms) pulse of light effects rapid release of a potent STX derivative and transient, spatially precise blockade of voltage-gated sodium channels (NaVs). We demonstrate the efficacy of STX-bpc for parametrically manipulating action potentials in mammalian neurons and brain slice. Additionally, we show the effectiveness of this reagent for silencing neural activity by dissecting sensory-evoked swimming in larval zebrafish. Photo-uncaging of STX-bpc is a straightforward method for non-invasive, reversible, spatiotemporally precise neural silencing without the need for genetic access, thus removing barriers for comparative research.


Asunto(s)
Neuronas , Pez Cebra , Animales , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Saxitoxina/farmacología , Saxitoxina/metabolismo , Saxitoxina/química , Potenciales de Acción/efectos de los fármacos , Humanos , Conducta Animal/efectos de los fármacos , Larva/efectos de los fármacos , Larva/metabolismo , Luz , Ratones
10.
Front Cell Neurosci ; 17: 1175895, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37275776

RESUMEN

De novo mutations in GNB1, encoding the Gß1 subunit of G proteins, cause a neurodevelopmental disorder with global developmental delay and epilepsy, GNB1 encephalopathy. Here, we show that mice carrying a pathogenic mutation, K78R, recapitulate aspects of the disorder, including developmental delay and generalized seizures. Cultured mutant cortical neurons also display aberrant bursting activity on multi-electrode arrays. Strikingly, the antiepileptic drug ethosuximide (ETX) restores normal neuronal network behavior in vitro and suppresses spike-and-wave discharges (SWD) in vivo. ETX is a known blocker of T-type voltage-gated Ca2+ channels and G protein-coupled potassium (GIRK) channels. Accordingly, we present evidence that K78R results in a gain-of-function (GoF) effect by increasing the activation of GIRK channels in cultured neurons and a heterologous model (Xenopus oocytes)-an effect we show can be potently inhibited by ETX. This work implicates a GoF mechanism for GIRK channels in epilepsy, identifies a new mechanism of action for ETX in preventing seizures, and establishes this mouse model as a pre-clinical tool for translational research with predicative value for GNB1 encephalopathy.

11.
Commun Biol ; 5(1): 779, 2022 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-35918471

RESUMEN

Mutations in HNF1A cause Maturity Onset Diabetes of the Young (HNF1A-MODY). To understand mechanisms of ß-cell dysfunction, we generated stem cell-derived pancreatic endocrine cells with hypomorphic mutations in HNF1A. HNF1A-deficient ß-cells display impaired basal and glucose stimulated-insulin secretion, reduced intracellular calcium levels in association with a reduction in CACNA1A expression, and accumulation of abnormal insulin granules in association with SYT13 down-regulation. Knockout of CACNA1A and SYT13 reproduce the relevant phenotypes. In HNF1A deficient ß-cells, glibenclamide, a sulfonylurea drug used in the treatment of HNF1A-MODY patients, increases intracellular calcium, and restores insulin secretion. While insulin secretion defects are constitutive in ß-cells null for HNF1A, ß-cells heterozygous for hypomorphic HNF1A (R200Q) mutations lose the ability to secrete insulin gradually; this phenotype is prevented by correction of the mutation. Our studies illuminate the molecular basis for the efficacy of treatment of HNF1A-MODY with sulfonylureas, and suggest promise for the use of cell therapies.


Asunto(s)
Diabetes Mellitus Tipo 2 , Insulina , Calcio/metabolismo , Diabetes Mellitus Tipo 2/genética , Factor Nuclear 1-alfa del Hepatocito/genética , Factor Nuclear 1-alfa del Hepatocito/metabolismo , Humanos , Insulina/metabolismo , Insulina Regular Humana , Células Madre/metabolismo , Sinaptotagminas
12.
Curr Protoc ; 1(6): e141, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34102035

RESUMEN

It is essential to generate isolated populations of human neuronal subtypes in order to understand cell-type-specific roles in brain function and susceptibility to disease pathology. Here we describe a protocol for in-parallel generation of cortical glutamatergic (excitatory) and GABAergic (inhibitory) neurons from human pluripotent stem cells (hPSCs) by using the neurogenic transcription factors Ngn2 and a combination of Ascl1 and Dlx2, respectively. In contrast to the majority of neural transdifferentiation protocols that use transient lentiviral infection, the use of stable hPSC lines carrying doxycycline-inducible transcription factors allows neuronal differentiation to be initiated by addition of doxycycline and neural medium. This article presents a method to generate lentivirus from cultured mammalian cells and establish stable transcription factor-expressing cell lines (Basic Protocol 1), followed by a method for monolayer excitatory and inhibitory neuronal differentiation from the established lines (Basic Protocol 2). The resulting neurons reproducibly exhibit properties consistent with human cortical neurons, including the expected morphologies, expression of glutamatergic and GABAergic genes, and functional properties. Our approach enables the scalable and rapid production of human neurons suitable for modeling human brain diseases in a subtype-specific manner and examination of differential cellular vulnerability. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Lentivirus production and generation of stable hPSC lines Support Protocol 1: Expansion and maintenance of hPSCs Basic Protocol 2: Differentiation of EX- and IN-neurons Support Protocol 2: Experimental methods for validation of EX- and IN-neurons.


Asunto(s)
Células Madre Pluripotentes , Animales , Diferenciación Celular , Células Cultivadas , Humanos , Neurogénesis , Neuronas
13.
J Clin Invest ; 131(8)2021 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-33630762

RESUMEN

Bardet-Biedl syndrome (BBS) is a rare autosomal recessive disorder caused by mutations in genes encoding components of the primary cilium and is characterized by hyperphagic obesity. To investigate the molecular basis of obesity in human BBS, we developed a cellular model of BBS using induced pluripotent stem cell-derived (iPSC-derived) hypothalamic arcuate-like neurons. BBS mutations BBS1M390R and BBS10C91fsX95 did not affect neuronal differentiation efficiency but caused morphological defects, including impaired neurite outgrowth and longer primary cilia. Single-cell RNA sequencing of BBS1M390R hypothalamic neurons identified several downregulated pathways, including insulin and cAMP signaling and axon guidance. Additional studies demonstrated that BBS1M390R and BBS10C91fsX95 mutations impaired insulin signaling in both human fibroblasts and iPSC-derived neurons. Overexpression of intact BBS10 fully restored insulin signaling by restoring insulin receptor tyrosine phosphorylation in BBS10C91fsX95 neurons. Moreover, mutations in BBS1 and BBS10 impaired leptin-mediated p-STAT3 activation in iPSC-derived hypothalamic neurons. Correction of the BBS mutation by CRISPR rescued leptin signaling. POMC expression and neuropeptide production were decreased in BBS1M390R and BBS10C91fsX95 iPSC-derived hypothalamic neurons. In the aggregate, these data provide insights into the anatomic and functional mechanisms by which components of the BBSome in CNS primary cilia mediate effects on energy homeostasis.


Asunto(s)
Síndrome de Bardet-Biedl/metabolismo , Chaperoninas/metabolismo , Hipotálamo/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Proteínas Asociadas a Microtúbulos/metabolismo , Mutación Missense , Neuronas/metabolismo , Sistemas de Mensajero Secundario , Sustitución de Aminoácidos , Animales , Síndrome de Bardet-Biedl/genética , Chaperoninas/genética , AMP Cíclico/genética , AMP Cíclico/metabolismo , Femenino , Células HEK293 , Humanos , Masculino , Ratones , Ratones Transgénicos , Proteínas Asociadas a Microtúbulos/genética
14.
Cell Rep ; 33(4): 108303, 2020 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-33113364

RESUMEN

Gain-of-function (GOF) variants in K+ channels cause severe childhood epilepsies, but there are no mechanisms to explain how increased K+ currents lead to network hyperexcitability. Here, we introduce a human Na+-activated K+ (KNa) channel variant (KCNT1-Y796H) into mice and, using a multiplatform approach, find motor cortex hyperexcitability and early-onset seizures, phenotypes strikingly similar to those of human patients. Although the variant increases KNa currents in cortical excitatory and inhibitory neurons, there is an increase in the KNa current across subthreshold voltages only in inhibitory neurons, particularly in those with non-fast-spiking properties, resulting in inhibitory-neuron-specific impairments in excitability and action potential (AP) generation. We further observe evidence of synaptic rewiring, including increases in homotypic synaptic connectivity, accompanied by network hyperexcitability and hypersynchronicity. These findings support inhibitory-neuron-specific mechanisms in mediating the epileptogenic effects of KCNT1 channel GOF, offering cell-type-specific currents and effects as promising targets for therapeutic intervention.


Asunto(s)
Potenciales de Acción/genética , Epilepsia/genética , Neuronas GABAérgicas/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Canales de potasio activados por Sodio/metabolismo , Convulsiones/genética , Animales , Modelos Animales de Enfermedad , Humanos , Ratones
15.
Theranostics ; 9(5): 1232-1246, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30867827

RESUMEN

The study of human neuromuscular diseases has traditionally been performed in animal models, due to the difficulty of performing studies in human subjects. Despite the unquestioned value of animal models, inter-species differences hamper the translation of these findings to clinical trials. Tissue-engineered models of the neuromuscular junction (NMJ) allow for the recapitulation of the human physiology in tightly controlled in vitro settings. Methods: Here we report the first human patient-specific tissue-engineered model of the neuromuscular junction (NMJ) that combines stem cell technology with tissue engineering, optogenetics, microfabrication and image processing. The combination of custom-made hardware and software allows for repeated, quantitative measurements of NMJ function in a user-independent manner. Results: We demonstrate the utility of this model for basic and translational research by characterizing in real time the functional changes during physiological and pathological processes. Principal Conclusions: This system holds great potential for the study of neuromuscular diseases and drug screening, allowing for the extraction of quantitative functional data from a human, patient-specific system.


Asunto(s)
Modelos Teóricos , Enfermedades Neuromusculares/patología , Enfermedades Neuromusculares/fisiopatología , Optogenética/métodos , Ingeniería de Tejidos/métodos , Humanos , Células Madre Pluripotentes Inducidas/fisiología , Unión Neuromuscular/patología , Unión Neuromuscular/fisiología , Unión Neuromuscular/fisiopatología
16.
J Pharmacol Exp Ther ; 324(1): 342-51, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17940199

RESUMEN

GPR35 is a G protein-coupled receptor recently "de-orphanized" using high-throughput intracellular calcium measurements in clonal cell lines expressing a chimeric G-protein alpha-subunit. From these screens, kynurenic acid, an endogenous metabolite of tryptophan, and zaprinast, a synthetic inhibitor of cyclic guanosine monophosphate-specific phosphodiesterase, emerged as potential agonists for GPR35. To investigate the coupling of GPR35 to natively expressed neuronal signaling pathways and effectors, we heterologously expressed GPR35 in rat sympathetic neurons and examined the modulation of N-type (Ca(V)2.2) calcium channels. In neurons expressing GPR35, calcium channels were inhibited in the absence of overt agonists, indicating a tonic receptor activity. Application of kynurenic acid or zaprinast resulted in robust voltage-dependent calcium current inhibition characteristic of Gbetagamma-mediated modulation. Both agonist-independent and -dependent effects of GPR35 were blocked by Bordetella pertussis toxin pretreatment indicating the involvement of G(i/o) proteins. In neurons expressing GPR35a, a short splice variant of GPR35, zaprinast was more potent (EC(50) = 1 microM) than kynurenic acid (58 microM) but had a similar efficacy (approximately 60% maximal calcium current inhibition). Expression of GPR35b, which has an additional 31 residues at the N terminus, produced similar results but with much greater variability. Both GPR35a and GPR35b appeared to have similar expression patterns when fused to fluorescent proteins. These results suggest a potential role for GPR35 in regulating neuronal excitability and synaptic release.


Asunto(s)
Canales de Calcio Tipo N/fisiología , Neuronas/fisiología , Receptores Acoplados a Proteínas G/fisiología , Ganglio Cervical Superior/fisiología , Animales , Bloqueadores de los Canales de Calcio/farmacología , ADN Complementario/genética , Células HeLa , Humanos , Ácido Quinurénico/farmacología , Masculino , Toxina del Pertussis , Isoformas de Proteínas/agonistas , Isoformas de Proteínas/genética , Isoformas de Proteínas/fisiología , Purinonas/farmacología , Ratas , Ratas Wistar , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/genética
17.
Travel Med Infect Dis ; 6(5): 259-75, 2008 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-18760249

RESUMEN

BACKGROUND: Practitioners are often fearful of giving vaccinations and prophylactic medications to pregnant travelers. And yet pregnancy is often a time of heightened danger from travel-related infections and illnesses. METHOD: Literature search and communication with researchers. RESULTS: With a few exceptions, there is little systematic research regarding the use of prophylactic medications and vaccines during pregnancy. Case reports and small studies do, however, indicate an increased risk in pregnancy from many of the preventable illnesses, and there is some data to support the use of preventive measures. CONCLUSIONS: The authors present some non-medical interventions that may be used to limit exposure to a number of disease processes. They then review the available information regarding the safety and efficacy of routine and travel-related vaccines as well as prophylactic medications for malaria, diarrhea, motion sickness and altitude sickness. When there are no obstetrical or medical contraindications, travel-related illness can usually be safely prevented during pregnancy in much the same ways as in the non-pregnant state.


Asunto(s)
Complicaciones Infecciosas del Embarazo/prevención & control , Viaje , Vacunas/uso terapéutico , Mal de Altura/prevención & control , Diarrea/prevención & control , Femenino , Humanos , Malaria/prevención & control , Mareo por Movimiento/prevención & control , Embarazo , Vacunas/efectos adversos
18.
Transl Psychiatry ; 8(1): 85, 2018 04 18.
Artículo en Inglés | MEDLINE | ID: mdl-29666363

RESUMEN

Given its high penetrance, clearly delineated and evolutionary conserved genomic structure, mouse models of the 22q11.2 deletion provide an ideal organism-based and cell-based model of this well-established disease mutation for schizophrenia. In this study we examined the development of changes in intrinsic properties, action potential firing and synaptic transmission using whole-cell patch-clamp recordings of cultured embryonic cortical neurons from Df(16)A +/- and WT mice at DIV7 and DIV14, respectively. Compared to neurons from the WT littermates, significantly increased input resistance and decreased rising rate of action potential was observed in Df(16)A +/- mice at DIV7 but not at DIV14 indicative of delayed neuronal maturation. Neurons from Df(16)A +/- mice also showed significantly higher cellular excitability at both DIV7 and DIV14. Evaluation of Ca2+ homeostasis perturbation caused by 22q11.2 deletion using calcium imaging revealed a significantly lower amplitude of calcium elevation and a smaller area under the curve after depolarization in neurons from Df(16)A +/- mice at both DIV7 and DIV14. Furthermore, the properties of inhibitory synaptic events were significantly altered in Df(16)A +/- mice. We identified changes in mRNA expression profiles, especially in ion channels, receptors, and transporters that may underlie the neurophysiological effects of this mutation. Overall, we show a number of alterations in electrophysiological and calcium homeostatic properties of embryonic cortical neurons from a 22q11.2 deletion mouse model at different culture times and provide valuable insights towards revealing disease mechanisms and discovery of new therapeutic compounds.


Asunto(s)
Corteza Cerebral/embriología , Corteza Cerebral/fisiopatología , Cromosomas Humanos Par 22/genética , Neuronas/fisiología , Esquizofrenia/fisiopatología , Potenciales de Acción , Animales , Calcio/metabolismo , Modelos Animales de Enfermedad , Potenciales Postsinápticos Excitadores , Eliminación de Gen , Expresión Génica , Humanos , Ratones Transgénicos , Cultivo Primario de Células , Esquizofrenia/genética
19.
Neuron ; 97(4): 853-868.e6, 2018 02 21.
Artículo en Inglés | MEDLINE | ID: mdl-29398366

RESUMEN

Neuronal maturation requires dramatic morphological and functional changes, but the molecular mechanisms governing this process are not well understood. Here, we studied the role of Rbfox1, Rbfox2, and Rbfox3 proteins, a family of tissue-specific splicing regulators mutated in multiple neurodevelopmental disorders. We generated Rbfox triple knockout (tKO) ventral spinal neurons to define a comprehensive network of alternative exons under Rbfox regulation and to investigate their functional importance in the developing neurons. Rbfox tKO neurons exhibit defects in alternative splicing of many cytoskeletal, membrane, and synaptic proteins, and display immature electrophysiological activity. The axon initial segment (AIS), a subcellular structure important for action potential initiation, is diminished upon Rbfox depletion. We identified an Rbfox-regulated splicing switch in ankyrin G, the AIS "interaction hub" protein, that regulates ankyrin G-beta spectrin affinity and AIS assembly. Our data show that the Rbfox-regulated splicing program plays a crucial role in structural and functional maturation of postmitotic neurons.


Asunto(s)
Empalme Alternativo , Segmento Inicial del Axón/metabolismo , Factores de Empalme de ARN/metabolismo , Médula Espinal/embriología , Células 3T3 , Animales , Ancirinas/metabolismo , Proteínas de Unión al ADN , Células Madre Embrionarias/metabolismo , Regulación del Desarrollo de la Expresión Génica , Ratones , Ratones Noqueados , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nucleares/metabolismo , Médula Espinal/metabolismo
20.
Diabetes ; 67(1): 26-35, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28931519

RESUMEN

ß-Cells derived from stem cells hold great promise for cell replacement therapy for diabetes. Here we examine the ability of nuclear transfer embryonic stem cells (NT-ESs) derived from a patient with type 1 diabetes to differentiate into ß-cells and provide a source of autologous islets for cell replacement. NT-ESs differentiate in vitro with an average efficiency of 55% into C-peptide-positive cells, expressing markers of mature ß-cells, including MAFA and NKX6.1. Upon transplantation in immunodeficient mice, grafted cells form vascularized islet-like structures containing MAFA/C-peptide-positive cells. These ß-cells adapt insulin secretion to ambient metabolite status and show normal insulin processing. Importantly, NT-ES-ß-cells maintain normal blood glucose levels after ablation of the mouse endogenous ß-cells. Cystic structures, but no teratomas, were observed in NT-ES-ß-cell grafts. Isogenic induced pluripotent stem cell lines showed greater variability in ß-cell differentiation. Even though different methods of somatic cell reprogramming result in stem cell lines that are molecularly indistinguishable, full differentiation competence is more common in ES cell lines than in induced pluripotent stem cell lines. These results demonstrate the suitability of NT-ES-ß-cells for cell replacement for type 1 diabetes and provide proof of principle for therapeutic cloning combined with cell therapy.


Asunto(s)
Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/terapia , Células Madre Embrionarias/citología , Células Secretoras de Insulina/citología , Animales , Glucemia/metabolismo , Diferenciación Celular/fisiología , Línea Celular , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/inmunología , Células Madre Embrionarias/fisiología , Femenino , Citometría de Flujo , Glucosa/farmacología , Proteínas de Homeodominio/metabolismo , Humanos , Huésped Inmunocomprometido , Inmunohistoquímica , Insulina/metabolismo , Células Secretoras de Insulina/fisiología , Factores de Transcripción Maf de Gran Tamaño/metabolismo , Masculino , Ratones
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