Extracellular vesicle-based delivery of silencing sequences for the treatment of Machado-Joseph disease/spinocerebellar ataxia type 3.

Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominantly inherited ataxia worldwide. It is caused by an over-repetition of the trinucleotide CAG within the ATXN3 gene, which confers toxic properties to ataxin-3 (ATXN3) species. RNA interference technology has shown promising therapeutic outcomes but still lacks a non-invasive delivery method to the brain. Extracellular vesicles (EVs) emerged as promising delivery vehicles due to their capacity to deliver small nucleic acids, such as microRNAs (miRNAs). miRNAs were found to be enriched into EVs due to specific signal motifs designated as ExoMotifs. In this study, we aimed at investigating whether ExoMotifs would promote the packaging of artificial miRNAs into EVs to be used as non-invasive therapeutic delivery vehicles to treat MJD/SCA3. We found that miRNA-based silencing sequences, associated with ExoMotif GGAG and ribonucleoprotein A2B1 (hnRNPA2B1), retained the capacity to silence mutant ATXN3 (mutATXN3) and were 3-fold enriched into EVs. Bioengineered EVs containing the neuronal targeting peptide RVG on the surface significantly decreased mutATXN3 mRNA in primary cerebellar neurons from MJD YAC 84.2 and in a novel dual-luciferase MJD mouse model upon daily intranasal administration. Altogether, these findings indicate that bioengineered EVs carrying miRNA-based silencing sequences are a promising delivery vehicle for brain therapy.

Extracellular vesicles: Novel promising delivery systems for therapy of brain diseases.

Extracellular vesicles (EVs) are cell-derived membrane vesicles virtually secreted by all cells, including brain cells. EVs are a major term that includes apoptotic bodies, microvesicles and exosomes. The release of EVs has been recognized as an important modulator in cross-talking between neurons, astrocytes, microglia and oligodendrocytes, not only in central nervous system (CNS) physiology but also in neurodegenerative and neuroinflammatory disease states as well as in brain tumors, such as glioma. EVs are able to cross the blood brain barrier (BBB), spread to body fluids and reach distant tissues. This prominent spreading ability has suggested that EVs can be exploited into several different clinical applications ranging from biomarkers to therapeutic carriers. Exosomes, the well-studied group of EVs, have been emerging as a promising tool for therapeutic delivery strategies due to their intrinsic features, such as the stability, biocompatibility and stealth capacity when circulating in bloodstream, the ability to overcome natural barriers and inherent targeting properties. Over the last years, it became apparent that EVs can be loaded with specific cargoes directly in isolated EVs or by modulation of producer cells. In addition, the engineering of its membrane for targeting purposes is expected to allow generating carriers with unprecedented abilities for delivery in specific organs or tissues. Nevertheless, some challenges remain regarding the loading and targeting of EVs for which more research is necessary, and will be discussed in this review. Recently-emerged promising derivations are also discussed, such as exosome associated with adeno-associated virus (AAV) vectors (vexosomes), enveloped protein nanocages (EPNs) and exosome-mimetic nanovesicles. This article provides an updated review of this fast-progressing field of EVs and their role in brain diseases, particularly focusing in their therapeutic applications.

Doença de Behçet na infância / Behcet's disease in childhood

Objetivo: conscientizar os pediatras sobre o fato de que, mesmo sendo uma vascullite de ocorrência rara na infância, a Doença de Behçet deve ser lembrada no diagnóstico diferencial de estomatites recorrentes. Casuística e método: foram avaliados, retrospectivamente, os prontuários de 7 pacientes atendidos no ambulatório de Reumatologia Pediátrica da UNIFESP-EPM, no período de junho de 1996 a dezembro de 2000. Foram estudados os dados epidemiológicos, clínicos, laboratoriais, de evoluçäo e de tratamento.Resultados: dos 7 pacientes, 5 eram do sexo feminino (71,4 por cento), 4 da raça näo caucasóide (57,1 por cento), com idade média de início de doença de 8 anos e 11 meses (variaçäo de 6 meses a 13 anos e 8 meses), tempo médio de diagnóstico de 2 anos e 3 meses (variaçäo de 2 meses a 8 anos) e tempo médio de evoluçäo de 4 anos e 2 meses (3 pacientes sem seguimento). Os critérios maiores de diagnóstico foram: úlceras orais em 7 pacientes (100 por cento), úlceras genitais em 3 pacientes (42,8 por cento), alteraçöes oftalmológicas em 4 pacientes (57,1 por cento), vasculite cutânea em 1 paciente (14,2 por cento) e teste de patergia positivo em 1 paciente (14,2 por cento). Os critérios menores de diagnóstico foram: artralgia/artrite em 5 pacientes (71,4 por cento), história familiar em 2 pacientes (28,5 por cento) e trombose do seio sagital em 1 paciente (14,2 por cento). Os sintomas iniciais incluíram estomatites recorrentes (mais de 3 episódios de aftas dolorosas no período de 1 ano), úlceras genitais, artralgias, febre e perda de peso. Os achados laboratoriais mostraram discreta anemia em 1/6 pacientes, VHS>25 em 3/6 pacientes, hipergamaglobulina em 2/4 pacientes, presença do antígeno de histocompatibilidade B5 em apenas 2/7 pacientes. O tratamento constou de corticoesteróides em 5/7 pacientes (4 VO, 1 EV e 1 uso tópico), talidomida em 4/7 pacientes, colchicina em 2/7 pacientes e dapsona em 1/7 pacientes. A resposta foi favorável em 4/6, porém recorrente em 3/6 pacientes.Conclusäo: nossos resultados confirmam a importância de considerar o diagnóstico de doença de Behçet em regiöes com úlceras orais e genitais, especialmente úlceras orais recorrentes

[Behçet's disease in childhood]. / Doença de Behçet na infância.

OBJECTIVE: To make Pediatricians aware of the fact that they must investigate Behçet's disease while performing differential diagnosis of recurrent aphthous stomatitis, even though it is a vasculitis of rare occurrence in early life. METHODS: Between June 1996 and December 2000, we retrospectively evaluated seven patients of our Pediatric Rheumatology Unit. Demographic, clinical, and laboratory data as well as data regarding treatment and follow-up were presented. RESULTS: Five out of seven patients were female (71.4%), four were non-Caucasian (57.1%), the mean age at onset was 8 years and 11 months (variation of 6 months to 13 years and 8 months), the mean period until diagnosis was 2 years and 3 months (variation of 2 months to 8 years) and the mean follow-up period was 4 years and 2 months (three patients without follow-up). The major criteria of diagnosis were: oral ulcers in seven patients (100%), genital ulcers in three patients (42.8%), ophthalmic alterations in four patients (57.1%) cutaneous vasculitis in one patient (14.2%) and positive pathology test in one patient (14.2%). The minor criteria were: arthralgia/arthritis in five patients (71.4%), family history in two patients (28.5%), and sagittal sinus thrombosis in one patient (14.2%). The initial symptoms included recurrent aphthous stomatitis (more than three painful aphthous ulcers episodes in the period of 1 year), genital ulcers, arthralgia, fever and weight loss. The laboratory findings were: mild anemia in 1/6 patients, ESR>25 in 3/6 patients, increased serum gammaglobulin level in 2/4 patients, B5 histocompatibility antigen in 2/7 patients. The treatment included corticosteroids for 5/7 patients (4 oral, 1 intravenous and one local use), thalidomide for 4/7 patients, colchicine for 2/7 patients and dapsone for 1/7 patient. The outcome was favorable in 4/6, and 3/6 patients presented relapse. CONCLUSION: Our results confirm the importance of considering the diagnosis of Behçet's disease in patients with recurrent oral and genital ulcers.