Selective suppression of α-Synuclein in monoaminergic neurons of mice by intranasal delivery of targeted small interfering RNA or antisense oligonucleotides: Potential therapy for Parkinson's disease

Póster presentado en: ACNP (American College of Neuropsychopharmacology) 52nd Annual Conference, celebrada del 8 al 12 de diciembre de 2013 en Hollywood, Florida (Estados Unidos)Abstract publicado en: Neuropsychopharmacology 38:S419-S420 (2013). ISSN: 0893-133X. eISSN: 1740-634X. DOI:10.1038/npp.2013.280α-Synuclein (α-Syn) appears to play a crucial role in the pathogenesis of several neurodegenerative disorders including Parkinson's disease (PD). The brains of Parkinson patients typically contain insoluble intracellular protein inclusions called Lewy bodies. Increased neuronal α-Syn levels represent a major component of Lewy bodies and therefore, the suppression of α-Syn expression provides a valid therapeutic target for PD. The goal of this study was to assess the ability of various small interfering RNA (siRNA) and antisense oligonucleotide (ASO) sequences directed against α-Syn to downregulate endogenous or overexpressed α-Syn mRNA levels in BE-M17 neuroblastoma cells. Moreover, we evaluated the feasibility of reducing α-Syn expression selectively in PD-vulnerable brain areas including substantia nigra pars compacta (SNc), ventral tegmental area (VTA), locus coeruleus (LC) and dorsal raphe nucleus (DR) of mice after the internalization of conjugated siRNA/ASO molecules into monoamine neurons following intranasal administration. Conclusions: These results set the stage for the testing of these molecules as potential disease-modifying agents in neurotoxin-based and genetic models of PD linked to pathogenic increases in α-Syn. In this study we have characterized conjugated siRNA and ASO molecules that actively reduce endogenous α-Syn expression in vivo using the intranasal route to deliver directly siRNA/ASO into the brainPeer Reviewe

Brain tyrosinase overexpression implicates age-dependent neuromelanin production in Parkinson's disease pathogenesis

Brain tyrosinase; Neuromelanin production; Parkinson’sTirosinasa cerebral; Producció de neuromelanina; ParkinsonTirosinasa cerebral; Producción de neuromelanina; ParkinsonIn Parkinson's disease (PD) there is a selective degeneration of neuromelanin-containing neurons, especially substantia nigra dopaminergic neurons. In humans, neuromelanin accumulates with age, the latter being the main risk factor for PD. The contribution of neuromelanin to PD pathogenesis remains unknown because, unlike humans, common laboratory animals lack neuromelanin. Synthesis of peripheral melanins is mediated by tyrosinase, an enzyme also present at low levels in the brain. Here we report that overexpression of human tyrosinase in rat substantia nigra results in age-dependent production of human-like neuromelanin within nigral dopaminergic neurons, up to levels reached in elderly humans. In these animals, intracellular neuromelanin accumulation above a specific threshold is associated to an age-dependent PD phenotype, including hypokinesia, Lewy body-like formation and nigrostriatal neurodegeneration. Enhancing lysosomal proteostasis reduces intracellular neuromelanin and prevents neurodegeneration in tyrosinase-overexpressing animals. Our results suggest that intracellular neuromelanin levels may set the threshold for the initiation of PD

Disease-specific phenotypes in dopamine neurons from human iPS-based models of genetic and sporadic Parkinson's disease

Induced pluripotent stem cells (iPSC) offer an unprecedented opportunity to model human disease in relevant cell types, but it is unclear whether they could successfully model age-related diseases such as Parkinson's disease (PD). Here, we generated iPSC lines from seven patients with idiopathic PD (ID-PD), four patients with familial PD associated to the G2019S mutation in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene (LRRK2-PD) and four age- and sex-matched healthy individuals (Ctrl). Over long-time culture, dopaminergic neurons (DAn) differentiated from either ID-PD- or LRRK2-PD-iPSC showed morphological alterations, including reduced numbers of neurites and neurite arborization, as well as accumulation of autophagic vacuoles, which were not evident in DAn differentiated from Ctrl-iPSC. Further induction of autophagy and/or inhibition of lysosomal proteolysis greatly exacerbated the DAn morphological alterations, indicating autophagic compromise in DAn from ID-PD- and LRRK2-PD-iPSC, which we demonstrate occurs at the level of autophagosome clearance. Our study provides an iPSC-based in vitro model that captures the patients' genetic complexity and allows investigation of the pathogenesis of both sporadic and familial PD cases in a disease-relevant cell type

High LRRK2 Levels Fail to Induce or Exacerbate Neuronal Alpha-Synucleinopathy in Mouse Brain

The G2019S mutation in the multidomain protein leucine-rich repeat kinase 2 (LRRK2) is one of the most frequently identified genetic causes of Parkinson’s disease (PD). Clinically, LRRK2(G2019S) carriers with PD and idiopathic PD patients have a very similar disease with brainstem and cortical Lewy pathology (α-synucleinopathy) as histopathological hallmarks. Some patients have Tau pathology. Enhanced kinase function of the LRRK2(G2019S) mutant protein is a prime suspect mechanism for carriers to develop PD but observations in LRRK2 knock-out, G2019S knock-in and kinase-dead mutant mice suggest that LRRK2 steady-state abundance of the protein also plays a determining role. One critical question concerning the molecular pathogenesis in LRRK2(G2019S) PD patients is whether α-synuclein (aSN) has a contributory role. To this end we generated mice with high expression of either wildtype or G2019S mutant LRRK2 in brainstem and cortical neurons. High levels of these LRRK2 variants left endogenous aSN and Tau levels unaltered and did not exacerbate or otherwise modify α-synucleinopathy in mice that co-expressed high levels of LRRK2 and aSN in brain neurons. On the contrary, in some lines high LRRK2 levels improved motor skills in the presence and absence of aSN-transgene-induced disease. Therefore, in many neurons high LRRK2 levels are well tolerated and not sufficient to drive or exacerbate neuronal α-synucleinopathy

Advances in parkinson's disease: 200 years later

When James Parkinson described the classical symptoms of the disease he could hardly foresee the evolution of our understanding over the next two hundred years. Nowadays, Parkinson's disease is considered a complex multifactorial disease in which genetic factors, either causative or susceptibility variants, unknown environmental cues, and the potential interaction of both could ultimately trigger the pathology. Noteworthy advances have been made in different fields from the clinical phenotype to the decoding of some potential neuropathological features, among which are the fields of genetics, drug discovery or biomaterials for drug delivery, which, though recent in origin, have evolved swiftly to become the basis of research into the disease today. In this review, we highlight some of the key advances in the field over the past two centuries and discuss the current challenges focusing on exciting new research developments likely to come in the next few years. Also, the importance of pre-motor symptoms and early diagnosis in the search for more effective therapeutic options is discussed

Disease-specific phenotypes in dopamine neurons from human iPS-based models of genetic and sporadic Parkinson's disease.

19nonenoneSánchez-Danés A; Richaud-Patin Y; Carballo-Carbajal I; Jiménez-Delgado S; Caig C; Mora S; Di Guglielmo C; Ezquerra M; Patel B; Giralt A; Canals JM; Memo M; Alberch J; López-Barneo J; Vila M; Cuervo AM; Tolosa E; Consiglio A; Raya A.Sánchez Danés, A; Richaud Patin, Y; Carballo Carbajal, I; Jiménez Delgado, S; Caig, C; Mora, S; Di Guglielmo, C; Ezquerra, M; Patel, B; Giralt, A; Canals, Jm; Memo, Maurizio; Alberch, J; López Barneo, J; Vila, M; Cuervo, Am; Tolosa, E; Consiglio, A; Raya, A

Aberrant epigenome in iPSC-derived dopaminergic neurons from Parkinson's disease patients

The epigenomic landscape of Parkinson's disease () remains unknown. We performed a genomewide methylation and a transcriptome studies in induced pluripotent stem cell ()-derived dopaminergic neurons (n) generated by cell reprogramming of somatic skin cells from patients with monogenic 2-associated (L2) or sporadic (), and healthy subjects. We observed extensive methylation changes in n, and of expression, which were common in L2 and . No significant methylation differences were present in parental skin cells, undifferentiated s nor -derived neural cultures not-enriched-in-n. These findings suggest the presence of molecular defects in somatic cells which manifest only upon differentiation into the n cells targeted in . The methylation profile from n, but not from controls, resembled that of neural cultures not-enriched-in-n indicating a failure to fully acquire the epigenetic identity own to healthy n in . The -associated hypermethylation was prominent in gene regulatory regions such as enhancers and was related to the and/or protein downregulation of a network of transcription factors relevant to (1, 3C1, 4A, and 2). Using a patient-specific -based n model, our study provides the first evidence that epigenetic deregulation is associated with monogenic and sporadic PD

Disease-specific phenotypes in dopamine neurons from human iPS-based models of genetic and sporadic Parkinson's disease

Induced pluripotent stem cells (iPSC) offer an unprecedented opportunity to model human disease in relevant cell types, but it is unclear whether they could successfully model age-related diseases such as Parkinson's disease (PD). Here, we generated iPSC lines from seven patients with idiopathic PD (ID-PD), four patients with familial PD associated to the G2019S mutation in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene (LRRK2-PD) and four age- and sex-matched healthy individuals (Ctrl). Over long-time culture, dopaminergic neurons (DAn) differentiated from either ID-PD- or LRRK2-PD-iPSC showed morphological alterations, including reduced numbers of neurites and neurite arborization, as well as accumulation of autophagic vacuoles, which were not evident in DAn differentiated from Ctrl-iPSC. Further induction of autophagy and/or inhibition of lysosomal proteolysis greatly exacerbated the DAn morphological alterations, indicating autophagic compromise in DAn from ID-PD- and LRRK2-PD-iPSC, which we demonstrate occurs at the level of autophagosome clearance. Our study provides an iPSC-based in vitro model that captures the patients' genetic complexity and allows investigation of the pathogenesis of both sporadic and familial PD cases in a disease-relevant cell type

Aberrant epigenome in -derived dopaminergic neurons from Parkinson's disease patients

The epigenomic landscape of Parkinson's disease () remains unknown. We performed a genomewide methylation and a transcriptome studies in induced pluripotent stem cell ()-derived dopaminergic neurons (n) generated by cell reprogramming of somatic skin cells from patients with monogenic 2-associated (L2) or sporadic (), and healthy subjects. We observed extensive methylation changes in n, and of expression, which were common in L2 and . No significant methylation differences were present in parental skin cells, undifferentiated s nor -derived neural cultures not-enriched-in-n. These findings suggest the presence of molecular defects in somatic cells which manifest only upon differentiation into the n cells targeted in . The methylation profile from n, but not from controls, resembled that of neural cultures not-enriched-in-n indicating a failure to fully acquire the epigenetic identity own to healthy n in . The -associated hypermethylation was prominent in gene regulatory regions such as enhancers and was related to the and/or protein downregulation of a network of transcription factors relevant to (1, 3C1, 4A, and 2). Using a patient-specific -based n model, our study provides the first evidence that epigenetic deregulation is associated with monogenic and sporadic PD