Natalizumab-immunogenicity evaluation in patients with infusion related events or disease exacerbations.

Introduction: Natalizumab is a biologic drug for relapsing-remitting multiple sclerosis that may induce the generation of anti-drug antibodies in some patients. Anti-natalizumab antibodies (ANA) increase the risk of adverse events and reduce efficacy, being useful biomarkers for monitoring treatment response. Methods: Retrospective observational study including MS patients treated with natalizumab that experienced infusion-related events (IRE) or disease exacerbations (DE). ANA were tested by Elisa including a screening and a confirmation assay. Patients were further classified as transient (one positive result) or persistent (two or more positive results) ANA. Results: A total of 1251 MS patients were included and 153 (12.3%) had ANA with at least one single point determination, which were more frequent among patients with IRE compared to those with DE (21,6% vs.10.8%) during the first six infusions. Two or more determinations ANA were performed in 184 patients, being 31.5% permanently positive and 7.1% transiently positive. Interestingly, 26.1% of patients that experienced DE had persistent ANA, while 2.6% were transient. In contrast, 43% of patients with IRE had persistent ANA, and 9.3% had transient antibodies. Patients with persistent antibodies had more frequently high levels at the first sampling compared to patients with transient ANA. Conclusion: Real-world evidence shows that the presence of ANA is behind an important percentage of patients treated with natalizumab that experience IRE, as well as DE but in a lower degree. These findings support the need to systematically evaluate ANA towards a personalized management of these patients to avoid undesired complications.

A collection of three integration-free iPSCs derived from old male and female healthy subjects.

Here, we present the characterization of three iPSC lines derived from dermal fibroblasts of old healthy subjects. Fibroblasts were reprogrammed using Sendai viral vectors encoding OCT4, SOX2, KLF4 and c-MYC. The iPSCs expressed endogenous pluripotency markers, could generate the three germ layers (ectoderm, mesoderm and endoderm), maintained a stable karyotype, and were free from Sendai vectors and reprogramming factors. These integration-free iPSCs can serve for establishing control cell cultures in studies searching for phenotypes and mechanisms that could potentially be dysregulated in degenerative diseases.

An integration-free iPSC line, ICCSICi007-A, derived from a female Alzheimer's disease patient with the APOE-ε4/ε4 alleles.

The epsilon4 (ε4) allele of the APOE gene, which encodes the apolipoprotein E4 (ApoE4), is the strongest genetic risk factor known for late-onset Alzheimer´s disease (LOAD). Here, we present the characterization of an iPSC line generated from dermal fibroblasts of a female AD patient using Sendai viral vectors encoding the transcription factors OCT4, SOX2, KLF4 and c-MYC. The iPSCs maintained the original genotype, a normal karyotype, were free from Sendai viral vectors and reprogramming factors, presented a normal morphology, expressed endogenous pluripotency markers, and could be differentiated into ectodermal, mesodermal and endodermal cells, confirming its pluripotency.

Generation of an integration-free iPSC line, ICCSICi006-A, derived from a male Alzheimer's disease patient carrying the PSEN1-G206D mutation.

The familial form of Alzheimer's disease (FAD), which is caused by mutations in PRESENILIN 1 (PSEN1) and amyloid precursor protein (APP) genes, represents less than 5% of all AD cases and has an early-onset. We report the generation and characterization of an iPSC line derived from a FAD patient carrying the PSEN1-G206D mutation. The iPSC line maintained the original genotype, a normal karyotype, was free from Sendai viral vectors and reprogramming factors (OCT4, SOX2, KLF4 and c-MYC), presented a typical morphology, expressed endogenous pluripotency markers, and could be differentiated into ectodermal, mesodermal and endodermal cells, confirming its pluripotency.

Generation of an integration-free iPSC line, ICCSICi005-A, derived from a Parkinson's disease patient carrying the L444P mutation in the GBA1 gene.

The L444P mutation in the GBA1 gene which encodes ß-glucocerebrosidase-1, is a major risk factor for developing Parkinson's disease (PD) and dementia with Lewy bodies (DLB). We report the generation and characterization of an induced pluripotent stem cell (iPSC) line derived from a female PD patient carrying the L444P/wt mutation. The iPSC line presented a normal morphology, expressed endogenous pluripotency markers, could be differentiated into endodermal, mesodermal and ectodermal cells, was free from Sendai vectors and reprogramming factors, had a normal karyotype and maintained the original GBA1 genotype. Thus, this iPSC line can serve to establish cellular models of PD.

A collection of four integration-free iPSC lines derived from diagnosed sporadic Alzheimer's disease patients with different APOE alleles.

Genetic polymorphism of apolipoprotein E (APOE) confers differential susceptibility to late-onset Alzheimer's disease (LOAD). The ε3 allele of APOE, the most common isoform, does not represent a risk factor for LOAD. In contrast, the ε4 allele is the strongest genetic risk factor for this disease. Here, we present the characterization of four iPSC lines generated from dermal fibroblasts of diagnosed sporadic AD patients using Sendai viral vectors encoding OCT4, SOX2, KLF4 and c-MYC. The iPSCs expressed endogenous pluripotency markers, could be differentiated into the three germ layers, maintained the original genotypes, and were free from Sendai vectors and reprogramming factors.

A collection of integration-free iPSCs derived from Parkinson's disease patients carrying mutations in the GBA1 gene.

Mutations in the GBA1 gene, which encodes the lysosomal enzyme Glucocerebrosidase1 are major risk factors for Parkinson's disease (PD) and dementia with Lewy bodies (DLB). We have generated induced pluripotent stem cells (iPSCs) from fibroblasts of four PD patients carrying the N370S/wt or the L444P/wt heterozygous mutations in GBA1. The iPSCs presented a normal morphology, expressed endogenous pluripotency markers and could be differentiated into endodermal, mesodermal and ectodermal cells. These iPSCs were free from Sendai viral vectors and reprogramming factors, had a normal karyotype and maintained the original GBA1 genotype.

N370S-GBA1 mutation causes lysosomal cholesterol accumulation in Parkinson's disease.

BACKGROUND: Heterozygous mutations in the GBA1 gene, which encodes the lysosomal enzyme ß-glucocerebrosidase-1, increase the risk of developing Parkinson's disease, although the underlying mechanisms remain unclear. The aim of this study was to explore the impact of the N370S-GBA1 mutation on cellular homeostasis and vulnerability in a patient-specific cellular model of PD. METHODS: We isolated fibroblasts from 4 PD patients carrying the N370S/wild type GBA1 mutation and 6 controls to study the autophagy-lysosome pathway, endoplasmic reticulum stress, and Golgi apparatus structure by Western blot, immunofluorescence, LysoTracker and Filipin stainings, mRNA analysis, and electron microscopy. We evaluated cell vulnerability by apoptosis, reactive oxygen species and mitochondrial membrane potential with flow cytometry. RESULTS: The N370S mutation produced a significant reduction in ß-glucocerebrosidase-1 protein and enzyme activity and ß-glucocerebrosidase-1 retention within the endoplasmic reticulum, which interrupted its traffic to the lysosome. This led to endoplasmic reticulum stress activation and triggered unfolded protein response and Golgi apparatus fragmentation. Furthermore, these alterations resulted in autophagosome and p62/SQSTM1 accumulation. This impaired autophagy was a result of dysfunctional lysosomes, indicated by multilamellar body accumulation probably caused by increased cholesterol, enlarged lysosomal mass, and reduced enzyme activity. This phenotype impaired the removal of damaged mitochondria and reactive oxygen species production and enhanced cell death. CONCLUSIONS: Our results support a connection between the loss of ß-glucocerebrosidase-1 function, cholesterol accumulation, and the disruption of cellular homeostasis in GBA1-PD. Our work reveals new insights into the cellular pathways underlying PD pathogenesis, providing evidence that GBA1-PD shares common features with lipid-storage diseases. © 2017 International Parkinson and Movement Disorder Society.

Role of Nurr1 in the Generation and Differentiation of Dopaminergic Neurons from Stem Cells.

NURR1 is an essential transcription factor for the differentiation, maturation, and maintenance of midbrain dopaminergic neurons (DA neurons) as it has been demonstrated using knock-out mice. DA neurons of the substantia nigra pars compacta degenerate in Parkinson's disease (PD) and mutations in the Nurr1 gene have been associated with this human disease. Thus, the study of NURR1 actions in vivo is fundamental to understand the mechanisms of neuron generation and degeneration in the dopaminergic system. Here, we present and discuss findings indicating that NURR1 is a valuable molecular tool for the in vitro generation of DA neurons which could be used for modeling and studying PD in cell culture and in transplantation approaches. Transduction of Nurr1 alone or in combination with other transcription factors such as Foxa2, Ngn2, Ascl1, and Pitx3, induces the generation of DA neurons, which upon transplantation have the capacity to survive and restore motor behavior in animal models of PD. We show that the survival of transplanted neurons is increased when the Nurr1-transduced olfactory bulb stem cells are treated with GDNF. The use of these and other factors with the induced pluripotent stem cell (iPSC)-based technology or the direct reprogramming of astrocytes or fibroblasts into human DA neurons has produced encouraging results for the study of the cellular and molecular mechanisms of neurodegeneration in PD and for the search of new treatments for this disease.

Nurr1 blocks the mitogenic effect of FGF-2 and EGF, inducing olfactory bulb neural stem cells to adopt dopaminergic and dopaminergic-GABAergic neuronal phenotypes.

The transcription factor Nurr1 is expressed in the mouse olfactory bulb (OB), although it remains unknown whether it influences the generation of dopaminergic neurons (DA) (DA neurons) in cells isolated from this brain region. We found that expressing Nurr1 in proliferating olfactory bulb stem cells (OBSCs) produces a marked inhibition of cell proliferation and the generation of immature neurons immunoreactive for tyrosine hydroxylase (TH) concomitant with marked upregulations of Th, Dat, Gad, and Fgfr2 transcripts. In long-term cultures, these cells develop neurochemical and synaptic markers of mature-like mesencephalic DA neurons, expressing GIRK2, VMAT2, DAT, calretinin, calbindin, synapsin-I, and SV2. Concurring with the increase in both Th and Gad expression, a subpopulation of induced cells was both TH- and GAD-immunoreactive indicating that they are dopaminergic-GABAergic neurons. Indeed, these cells could mature to express VGAT, suggesting they can uptake and store GABA in vesicles. Remarkably, the dopamine D1 receptor agonist SKF-38393 induced c-Fos in TH(+) cells and dopamine release was detected in these cultures under basal and KCl-evoked conditions. By contrast, cotransducing the Neurogenin2 and Nurr1 transcription factors produced a significant decrease in the number of TH-positive neurons. Our results indicate that Nurr1 overexpression in OBSCs induces the formation of two populations of mature dopaminergic neurons with features of the ventral mesencephalon or of the OB, capable of responding to functional dopaminergic stimuli and of releasing dopamine. They also suggest that the accumulation of Fgfr2 by Nurr1 in OBSCs may be involved in the generation of DA neurons.