RESUMEN
Pro-protein convertase subtilisin/kexin 5 (PC5, also known as PC6) is a member of the subtilisin-like superfamily of serine proteases implicated in the maturation of latent precursor proteins into their functionally active derivatives. To investigate the functional roles, we have cloned the cDNA sequences encoding two candidate zebrafish PC5 convertases (designated as PCSK5.1 and PCSK5.2) co-orthologous to the single PC5 encoding gene (PCSK5) found in mammals. Both display syntenic correspondence to the human PCSK5 gene. Overall gene architecture has been conserved across species. While PC5.1 mRNA expression is very discrete within the otic vesicle and lateral line neuromasts, PC5.2 transcripts are more ubiquitously expressed within the central nervous system together with specific localization in various organs including liver, intestine, and otic vesicle. Zebrafish PC5.1-deficient embryos display abnormal neuromast deposition within the lateral line system and lack a normal touch response, consistent with the known sensory role that the lateral line plays in spatial awareness and sensing the environment.
Asunto(s)
Proproteína Convertasa 5/química , Proproteína Convertasa 5/metabolismo , Proteínas de Pez Cebra/química , Proteínas de Pez Cebra/metabolismo , Secuencia de Aminoácidos , Animales , Northern Blotting , Western Blotting , Embrión no Mamífero/metabolismo , Humanos , Hibridación in Situ , Ratones , Datos de Secuencia Molecular , Proproteína Convertasa 5/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Homología de Secuencia de Aminoácido , Pez Cebra , Proteínas de Pez Cebra/genéticaRESUMEN
BACKGROUND: Progranulin is a secreted high molecular weight growth factor bearing seven and one half copies of the cysteine-rich granulin-epithelin motif. While inappropriate over-expression of the progranulin gene has been associated with many cancers, haploinsufficiency leads to atrophy of the frontotemporal lobes and development of a form of dementia (frontotemporal lobar degeneration with ubiquitin positive inclusions, FTLD-U) associated with the formation of ubiquitinated inclusions. Recent reports indicate that progranulin has neurotrophic effects, which, if confirmed would make progranulin the only neuroprotective growth factor that has been associated genetically with a neurological disease in humans. Preliminary studies indicated high progranulin gene expression in spinal cord motor neurons. However, it is uncertain what the role of Progranulin is in normal or diseased motor neuron function. We have investigated progranulin gene expression and subcellular localization in cultured mouse embryonic motor neurons and examined the effect of progranulin over-expression and knockdown in the NSC-34 immortalized motor neuron cell line upon proliferation and survival. RESULTS: In situ hybridisation and immunohistochemical techniques revealed that the progranulin gene is highly expressed by motor neurons within the mouse spinal cord and in primary cultures of dissociated mouse embryonic spinal cord-dorsal root ganglia. Confocal microscopy coupled to immunocytochemistry together with the use of a progranulin-green fluorescent protein fusion construct revealed progranulin to be located within compartments of the secretory pathway including the Golgi apparatus. Stable transfection of the human progranulin gene into the NSC-34 motor neuron cell line stimulates the appearance of dendritic structures and provides sufficient trophic stimulus to survive serum deprivation for long periods (up to two months). This is mediated at least in part through an anti-apoptotic mechanism. Control cells, while expressing basal levels of progranulin do not survive in serum free conditions. Knockdown of progranulin expression using shRNA technology further reduced cell survival. CONCLUSION: Neurons are among the most long-lived cells in the body and are subject to low levels of toxic challenges throughout life. We have demonstrated that progranulin is abundantly expressed in motor neurons and is cytoprotective over prolonged periods when over-expressed in a neuronal cell line. This work highlights the importance of progranulin as neuroprotective growth factor and may represent a therapeutic target for neurodegenerative diseases including motor neuron disease.
Asunto(s)
Supervivencia Celular/fisiología , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Neuronas Motoras/metabolismo , Médula Espinal/metabolismo , Animales , Apoptosis/genética , Apoptosis/fisiología , Western Blotting , Línea Celular , Proliferación Celular , Supervivencia Celular/genética , Células Cultivadas , Clonación Molecular , Técnica del Anticuerpo Fluorescente , Ganglios Espinales/metabolismo , Ganglios Espinales/ultraestructura , Aparato de Golgi/metabolismo , Aparato de Golgi/ultraestructura , Granulinas , Humanos , Hibridación in Situ , Péptidos y Proteínas de Señalización Intercelular/genética , Masculino , Ratones , Microscopía Confocal , Neuronas Motoras/ultraestructura , Progranulinas , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Médula Espinal/ultraestructura , TransfecciónRESUMEN
BACKGROUND: Chronic Venous Disease is characterized by morphological abnormalities of the venous system. Affected limbs are classified in increasing clinical severity with the Clinical Etiological Anatomical and Pathological system from C0 to C6. Limbs assessed at C3 through C6 meet the criteria of Chronic Venous Insufficiency. Chronic Venous Insufficiency of the Lower Limbs is a very common pathology affecting approximately ~40% of the world's population. This study observes the use of the LivRelief Varicose Vein Cream, a Natural Health Product that is licensed for sale by Health Canada, for use in the treatment of varicose veins. METHODS: An open label, single arm interventional, pilot study was conducted to determine the feasibility of recruitment and data collection in this population. To accomplish this, the cream was provided to all enrolled subjects. Subsequently, objective and subjective measures were performed at baseline and after 6 weeks of at-home use. Recruitment and data collection targets of at least 70% were established and the data collected at both timepoints were compared and analyzed using a paired t-test. Results were also reported as proportions where appropriate. RESULTS: A total of 32 subjects were enrolled. The pre-defined feasibility objectives for recruitment and data collection were met with the enrolment of 97% of all screened patients and the collection of 94% of all scheduled data. The most significant therapeutic improvement was seen in the results of the Venous Clinical Severity Score where 66% of the treated legs experienced a decrease in severity after 6 weeks of treatment. P values were <0.0001 and 0.0003 for the left and right leg, respectively. CONCLUSION: It is feasible to recruit and collect data with the chosen outcome assessments within this population. Preliminary results suggest that the product could improve some of the clinical symptoms associated with the presence varicose veins. These results warrant further exploration in a longer, randomized and placebo-controlled study. TRIAL REGISTRATION: Clinicaltrial.gov: NCT03653793.
Asunto(s)
Enfermedad Crónica/tratamiento farmacológico , Crema para la Piel/administración & dosificación , Várices/tratamiento farmacológico , Insuficiencia Venosa/tratamiento farmacológico , Adulto , Anciano , Canadá/epidemiología , Enfermedad Crónica/epidemiología , Femenino , Humanos , Extremidad Inferior/fisiopatología , Masculino , Persona de Mediana Edad , Várices/epidemiología , Várices/fisiopatología , Venas/efectos de los fármacos , Venas/fisiopatología , Insuficiencia Venosa/epidemiología , Insuficiencia Venosa/fisiopatologíaRESUMEN
The development of effective neuroprotective therapies for Parkinson's disease (PD) has been severely hindered by the notable lack of an appropriate animal model for preclinical screening. Indeed, most models currently available are either acute in nature or fail to recapitulate all characteristic features of the disease. Here, we present a novel progressive model of PD, with behavioural and cellular features that closely approximate those observed in patients. Chronic exposure to dietary phytosterol glucosides has been found to be neurotoxic. When fed to rats, ß-sitosterol ß-d-glucoside (BSSG) triggers the progressive development of parkinsonism, with clinical signs and histopathology beginning to appear following cessation of exposure to the neurotoxic insult and continuing to develop over several months. Here, we characterize the progressive nature of this model, its non-motor features, the anatomical spread of synucleinopathy, and response to levodopa administration. In Sprague Dawley rats, chronic BSSG feeding for 4 months triggered the progressive development of a parkinsonian phenotype and pathological events that evolved slowly over time, with neuronal loss beginning only after toxin exposure was terminated. At approximately 3 months following initiation of BSSG exposure, animals displayed the early emergence of an olfactory deficit, in the absence of significant dopaminergic nigral cell loss or locomotor deficits. Locomotor deficits developed gradually over time, initially appearing as locomotor asymmetry and developing into akinesia/bradykinesia, which was reversed by levodopa treatment. Late-stage cognitive impairment was observed in the form of spatial working memory deficits, as assessed by the radial arm maze. In addition to the progressive loss of TH+ cells in the substantia nigra, the appearance of proteinase K-resistant intracellular α-synuclein aggregates was also observed to develop progressively, appearing first in the olfactory bulb, then the striatum, the substantia nigra and, finally, hippocampal and cortical regions. The slowly progressive nature of this model, together with its construct, face and predictive validity, make it ideal for the screening of potential neuroprotective therapies for the treatment of PD.
Asunto(s)
Encéfalo/patología , Modelos Animales de Enfermedad , Actividad Motora/fisiología , Neuronas/patología , Enfermedad de Parkinson Secundaria/patología , Animales , Encéfalo/metabolismo , Encéfalo/fisiopatología , Neuronas/metabolismo , Enfermedad de Parkinson Secundaria/metabolismo , Enfermedad de Parkinson Secundaria/fisiopatología , Ratas , Ratas Sprague-Dawley , Sitoesteroles , alfa-Sinucleína/metabolismoRESUMEN
BACKGROUND: Progranulin (PGRN) encoded by the GRN gene, is a secreted glycoprotein growth factor that has been implicated in many physiological and pathophysiological processes. PGRN haploinsufficiency caused by autosomal dominant mutations within the GRN gene leads to progressive neuronal atrophy in the form of frontotemporal lobar degeneration (FTLD). This form of the disease is associated with neuronal inclusions that bear the ubiquitinated TAR DNA Binding Protein-43 (TDP-43) molecular signature (FTLD-U). The neurotrophic properties of PGRN in vitro have recently been reported but the role of PGRN in neurons is not well understood. Here we document the neuronal expression and functions of PGRN in spinal cord motoneuron (MN) maturation and branching in vivo using zebrafish, a well established model of vertebrate embryonic development. RESULTS: Whole-mount in situ hybridization and immunohistochemical analyses of zebrafish embryos revealed that zfPGRN-A is expressed within the peripheral and central nervous systems including the caudal primary (CaP) MNs within the spinal cord. Knockdown of zfPGRN-A mRNA translation mediated by antisense morpholino oligonucleotides disrupted normal CaP MN development resulting in both truncated MNs and inappropriate early branching. Ectopic over-expression of zfPGRN-A mRNA resulted in increased MN branching and rescued the truncation defects brought about by knockdown of zfPGRN-A expression. The ability of PGRN to interact with established MN developmental pathways was tested. PGRN over-expression was found to reverse the truncation defect resulting from knockdown of Survival of motor neuron 1 (smn1). This is involved in small ribonucleoprotein biogenesis RNA processing, mutations of which cause Spinal Muscular Atrophy (SMA) in humans. It did not reverse the MN defects caused by interfering with the neuronal guidance pathway by knockdown of expression of NRP-1, a semaphorin co-receptor. CONCLUSIONS: Expression of PGRN within MNs and the observed phenotypes resulting from mRNA knockdown and over-expression are consistent with a role in the regulation of spinal cord MN development and branching. This study presents the first in vivo demonstration of the neurotrophic properties of PGRN and suggests possible future therapeutic applications in the treatment of neurodegenerative diseases.