RESUMEN
Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are neurodegenerative disorders of the aging population characterized by the accumulation of α-synuclein (α-syn). The mechanisms triggering α-syn toxicity are not completely understood, however, c-terminus truncation of α-syn by proteases such as calpain may have a role. Therefore, inhibition of calpain may be of value. The main objective of this study was to evaluate the effects of systemically administered novel low molecular weight calpain inhibitors on α-syn pathology in a transgenic mouse model. For this purpose, non-tg and α-syn tg mice received the calpain inhibitors - Gabadur, Neurodur or a vehicle, twice a day for 30 days. Immunocytochemical analysis showed a 60% reduction in α-syn deposition using Gabadur and a 40% reduction using Neurodur with a concomitant reduction in c-terminus α-syn and improvements in neurodegeneration. Western blot analysis showed a 77% decrease in α-spectrin breakdown products (SBDPs) SBDPs with Gabadur and 63% reduction using Neurodur. There was a 65% reduction in the active calpain form with Gabadur and a 45% reduction with Neurodur. Moreover, treatment with calpain inhibitors improved activity performance of the α-syn tg mice. Taken together, this study suggests that calpain inhibition might be considered in the treatment of synucleinopathies.
Asunto(s)
Calpaína/antagonistas & inhibidores , Glicoproteínas/farmacología , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Modelos Animales de Enfermedad , Inmunohistoquímica , Enfermedad por Cuerpos de Lewy/tratamiento farmacológico , Enfermedad por Cuerpos de Lewy/etiología , Ratones , Ratones Transgénicos , Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Enfermedad de Parkinson/tratamiento farmacológico , Enfermedad de Parkinson/etiología , alfa-Sinucleína/químicaRESUMEN
After an acute ischemia/reperfusion of the rat retina, the activation of cytotoxic proteases, including calpain, results in necrosis and apoptosis of retinal ganglion cells resulting in their degeneration. Using a systemically administered calpain inhibitor that crosses the blood-retinal barrier would provide for novel systemic intervention that protects the retina from acute injury and loss of function. Herein, we study a novel calpain peptide inhibitor, cysteic-leucyl-argininal (CYLA), in an in-vivo rat model of retinal ischemia to determine functional protection using electroretinography. The CYLA prodrug was administered intraperitoneally before and/or after ischemia-reperfusion at concentrations of 20-40 mg/kg. We found that administering 20 mg/kg of CYLA only after ischemia provides significant preservation of retinal function.
Asunto(s)
Calpaína/antagonistas & inhibidores , Isquemia/tratamiento farmacológico , Leupeptinas/uso terapéutico , Enfermedades de la Retina/tratamiento farmacológico , Vasos Retinianos/efectos de los fármacos , Animales , Isquemia/fisiopatología , Leupeptinas/farmacología , Masculino , Ratas , Ratas Sprague-Dawley , Enfermedades de la Retina/fisiopatología , Vasos Retinianos/fisiopatologíaRESUMEN
Axonal injury is the major correlate of permanent disability in neurodegenerative diseases such as multiple sclerosis (MS), especially in secondary-progressive MS which follows relapsing-remitting disease course. Proteolytic enzyme, calpain, is a potential candidate for causing axonal injury. Most current treatment options only target the inflammatory component of MS. Previous work using calpain inhibitor CYLA in our laboratory showed significant reduction in clinical sign, demyelination and tissue calpain content in acute experimental autoimmune encephalomyelitis (EAE). Here we evaluated markers of axonal injury (amyloid precursor protein, Na(v)1.6 channels), neuronal calpain content and the effect of CYLA on axonal protection using histological methods in chronic EAE [myelin oligodendrocyte glycoprotein (MOG)-induced disease model of MS]. Intraperitoneal application of CYLA (2 mg/mouse/day) significantly reduced the clinical signs, tissue calpain content, demyelination and inflammatory infiltration of EAE. Similarly, markers for axonal injury were barely detectable in the treated mice. Thus, this novel drug, which markedly suppresses the disease course, axonal injury and its progression, is a candidate for the treatment of a neurodegenerative disease such as multiple sclerosis.
Asunto(s)
Axones/efectos de los fármacos , Encefalomielitis Autoinmune Experimental/tratamiento farmacológico , Encefalomielitis Autoinmune Experimental/patología , Glicoproteínas/uso terapéutico , Análisis de Varianza , Animales , Axones/patología , Calpaína/antagonistas & inhibidores , Calpaína/metabolismo , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/inducido químicamente , Encefalomielitis Autoinmune Experimental/complicaciones , Leupeptinas/uso terapéutico , Ratones , Ratones Endogámicos C57BL , Proteínas de la Mielina , Glicoproteína Asociada a Mielina , Glicoproteína Mielina-Oligodendrócito , Canal de Sodio Activado por Voltaje NAV1.6 , Proteínas del Tejido Nervioso/metabolismo , Fosfopiruvato Hidratasa/metabolismo , Índice de Severidad de la Enfermedad , Tinción con Nitrato de Plata , Canales de Sodio/metabolismoRESUMEN
Aberrant activation of calpain plays a key role in the pathophysiology of several neurodegenerative disorders. Calpain is increasingly expressed in inflammatory cells in EAE and is significantly elevated in the white matter of patients with multiple sclerosis, thus calpain inhibition could be a target for therapeutic intervention. The experiments reported here employed a myelin oligodendrocyte glycoprotein-induced disease model in C57Bl/6 mice (EAE) and a novel calpain inhibitor, targeted to nervous tissue. CYLA was found to reduce clinical signs of EAE and prevent demyelination and inflammatory infiltration in a dose- and time-dependent manner. Oral administration of the diacetal prodrug was equally effective.