Huntington’s disease is an autosomal-dominant neurodegenerative disease caused by CAG expansion in exon 1 of the huntingtin (HTT) gene. Since mutant huntingtin (mHTT) protein is the root cause of Huntington’s disease, oligonucleotide-based therapeutic approaches using small interfering RNAs (siRNAs) and antisense oligonucleotides designed to specifically silence mHTT may be novel therapeutic strategies for Huntington’s disease. Unfortunately, the lack of an effective in vivo delivery system remains a major obstacle to realizing the full potential of oligonucleotide therapeutics, especially regarding the delivery of oligonucleotides to the cortex and striatum, the most severely affected brain regions in Huntington’s disease. In this study, we present a synthetic biology strategy that integrates the naturally existing exosome-circulating system with artificial genetic circuits for self-assembly and delivery of mHTT-silencing siRNA to the cortex and striatum. We designed a cytomegalovirus promoter-directed genetic circuit encoding both a neuron-targeting rabies virus glycoprotein tag and an mHTT siRNA. After being taken up by mouse livers after intravenous injection, this circuit was able to reprogramme hepatocytes to transcribe and self-assemble mHTT siRNA into rabies virus glycoprotein-tagged exosomes. The mHTT siRNA was further delivered through the exosome-circulating system and guided by a rabies virus glycoprotein tag to the cortex and striatum. Consequently, in three mouse models of Huntington’s disease treated with this circuit, the levels of mHTT protein and toxic aggregates were successfully reduced in the cortex and striatum, therefore ameliorating behavioural deficits and striatal and cortical neuropathologies. Overall, our findings establish a convenient, effective and safe strategy for self-assembly of siRNAs in vivo that may provide a significant therapeutic benefit for Huntington’s disease.

This study showed that a series of neuropathological changes reflected by oculomotor abnormalities appeared preferentially in preclinical stage of SCA3. Accordingly, objective oculomotor preclinical signs may be useful to detect the optimum time-point for therapeutic interventions in future clinical trials of SCA3. Larger and longitudinal data are warranted to confirm our results.

Wilson disease (WD) is characterized by the accumulation of copper arising from a mutation in the ATP7B gene. Penicillamine (PA) makes 10–50% of the patients with neurologic symptoms neurologically worse at the early stage of administration. The aim of this study was to determine how the copper metabolism changes and whether the change impairs the brain of toxic milk (tx) mice, an animal model of WD, during the PA administration. The free copper and protein-bound copper concentrations in the serum, cortex and basal ganglia of tx mice with PA administration for 3 days, 10 days and 14 days, respectively, were investigated. The expression of copper transporters, ATP7A and CTR1,was analyzed by real-time quantitative PCR, immunofluorescence and Western blot. Then SOD, MDA and GSH/GSSG were detected to determine whether the oxidative stress changed correspondingly. The results revealed the elevated free copper concentrations in the serum and brain, and declined protein-bound copper concentrations in the brain of tx mice during PA administration. Meanwhile, transiently increased expression of ATP7A and CTR1 was observed generally in the brain parenchyma by immunofluorescence, real-time quantitative PCR and Western blot. Additionally, ATP7A and CTR1 were observed to locate mainly at Golgi apparatus and cellular membrane respectively. Intense staining of ATP7A in the choroid plexus was found in tx mice on the 3rd and 10th day of PA treatment, but rare staining of ATP7A and CTR1 in the blood-brain barrier (BBB). Decreased GSH/GSSG and increased MDA concentrations were also viewed in the cortex and basal ganglia. Our results suggested the elevated free copper concentrations in the brain might lead to the enhanced oxidative stress during PA administration. The increased free copper in the brain might come from the copper mobilized from brain parenchyma cells but not from the serum according to the ATP7A and CTR1 expression analysis.

Objectives: There are limited pharmacological treatments for patients with neurological Wilson's disease (WD) and a history of copper-chelating treatment failure. Methods: We retrospectively evaluated the clinical records of 38 patients with WD who were treated with sodium dimercaptopropanesulfonate (DMPS) and zinc (group 1) or zinc alone (group 2). All patients had a history of neurological deterioration during their previous treatment with D-penicillamine (DPA). Results: Twenty-one patients were treated with intravenous DMPS for 4 weeks, followed by zinc gluconate for 6 months, and the treatment protocol was repeated twice. Relative to the baseline, repeated DMPS therapy and zinc maintenance therapy decreased neurological scores continuously (p < 0.01). Sixteen patients (76.2%) demonstrated neurological improvements after 1 year of therapy and four patients (19.0%) exhibited neurological deterioration at the follow-up session. In addition, 17 patients were treated with zinc monotherapy for 12 months. Two patients (11.8%) demonstrated neurological improvements and five patients (29.4%) exhibited neurological deterioration. Compared with the patients in group 2, a greater improvement ratio (p < 0.01) and lower deterioration ratio (p < 0.01) were observed in the patients in group 1 after 1 year of therapy. Conclusions: Our findings indicate that the safety and efficacy of combined treatment of DMPS and zinc is superior to those of zinc monotherapy in patients with neurological WD with a history of DPA treatment failure.

Objectives: None of the previous studies have focused on the genetic effect on neurological worsening in neurological Wilson’s disease (WD) patients following chelator therapy. We aimed to evaluate the clinical and genetic role in the occurrence of neurological worsening.Methods: We retrospectively reviewed the medical records of neurological WD patients who received initial chelator therapy and genetic test. Clinical, laboratory, and genetic data were collected. The genotype was classified into two types: 1) severe mutation genotype: patients who carried at least one of the following three types of mutations: frameshift mutation, splicing mutation, or nonsense mutation; 2) non-severe mutation genotype: patients who only carried missense mutations. Then, the clinical features and genotype of the patients with and without neurological worsening were investigated.Results: Forty-seven neurological WD patients were identified with a median age at onset of 16.17 years (range 7.75–47 years) and 35 (74.5%) males. The mean interval from onset to diagnosis was 0.6 years (range: 0.5 months-6.25 years). Neurological deterioration was observed in 29 patients (61.7%) and the other 18 patients (38.3%) were stable or improved during anti-copper treatment. The neurological worsening was completely irreversible in 6 cases (20.7%) and partially irreversible in 16 cases (55.2%). The common deteriorated symptoms were as follows: rigidity in 20 cases (69%), speech difficulties in 20 cases (69%)), walking difficulties in 13 cases (44.8%), dysphagia in 9 cases (31%), and salivation in 9 cases (31%). The patients with neurological worsening had significantly younger age (p = 0.028), shorter delayed diagnosis time (p = 0.011), higher rate of dystonia (p = 0.003), and severe mutation genotype (p = 0.036), compared to those without neurological worsening.Conclusion: We found that younger age of onset, the presence of dystonia, and genotype with severe mutations may be predictive of neurological worsening in the neurological WD patients that received chelator therapy. For those patients, chelator therapy should be given with caution and needs closer observation during follow-up.

ObjectiveTo evaluate different injury factors and pathological characteristics of the brain at different disease stages in toxic milk (TX) mice, an animal model of Wilson's disease (WD).MethodsThirty TX mice (10 each at 3, 6 and 12 months old) and 30 age‐matched C57 mice were used in this study. Corrected phase (CP) values were determined from susceptibility‐weighted images. Myelin content was determined by measuring inhibition optical density values of Luxol fast blue‐stained sections. Neurofilament protein 68 kDa (NF68), β‐amyloid precursor protein (β‐APP), and myelin basic protein (MBP) levels, as well as copper and iron content, in brain nuclei of the TX mouse were evaluated. Gene amplification ratios for catalase (CAT), GSH peroxidase (GSH‐PX), nitric oxide synthase (NOS), and superoxide dismutase (SOD) in mouse brain were also determined.ResultsCompared with C57 mice, neuronal cell counts were decreased in 12‐months‐old TX mice (p = .011). Myelin content was decreased in the lenticular nucleus (p = .029), thalamus (p = .030), and brainstem (p = .034) of 6‐months‐old TX mice; decreases in the corresponding nuclei (p = .044, .037, and .032, respectively) were also found in 12‐months‐old TX mice. MBP values were lower in the lenticular nucleus and thalamus (p = .027 and .016, respectively) of 6‐months‐old TX mice and in the corresponding nuclei (p = .24 and .040) of 12‐months‐old TX mice. NF‐68 values were lower in the lenticular nucleus and thalamus (p = .034 and .037, respectively) of 6‐months‐old TX mice and in the corresponding nuclei (p = .006 and .012) of 12‐months‐old TX mice. β‐APP values were higher in the thalamus of 6‐months‐old (p = .037) and 12‐months‐old (p = .012) TX mice. Iron content was higher in the lenticular nucleus, thalamus, and cerebellum (p = .044, .038, and .029, respectively) of 6‐months‐old TX mice and in the corresponding nuclei (p = .017, .024, and .029) of 12‐months‐old TX mice. The NOS gene amplification multiple was higher (p = .039), whereas the SOD1 gene amplification multiple was lower (p = .041) in 12‐months‐old TX mice. There was no correlation between metal content or oxidation index and pathological index.ConclusionsThe pathological characteristics of the brains of TX mice may differ at different ages. Different pathogenic factors, including copper and iron deposition and abnormal oxidative stress, are present at different stages.

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