Biology subjects

Manole, A.

Publications and source records attributed to Manole, A..

5 recordsLinked to original sources

bioRxiv2026

iPSC-derived extracellular vesicles rescue deficits in human and mouse models of Parkinsons disease

Parkinsons disease (PD) pathogenesis often involves progressive -synuclein (-Syn)-mediated neuronal dysfunction, yet the earliest cellular events that link -Syn pathology to circuit failure remain poorly defined. Here, we used human induced pluripotent stem cell (iPSC)-derived dopaminergic (DA) neurons from patients carrying the familial A53T SNCA mutation to reconstruct a temporal course of dysfunction in vitro. We identified a biphasic trajectory with an early phase of hyperexcitability, characterized by elevated spontaneous firing, followed by a progressive transition into hypoexcitability as the neurons mature, accompanied by reduced network activity, synaptic dysfunction, and -Syn accumulation. Transcriptomic profiling at the critical transition point revealed a dual transcriptional signature, with upregulation of stress-inflammatory pathways (p53, JAK-STAT, apoptosis) coupled with systematic downregulation of metabolic and synaptic maintenance genes. This molecular profile preceded functional collapse, linking early hyperactivity-driven metabolic stress to subsequent neuronal exhaustion. To counteract this pathology, we used extracellular vesicles (EVs), small membrane-bound particles carrying intercellular signals, as a cell-free treatment approach. Strikingly, treatment with EVs derived from healthy iPSCs completely rescued both electrophysiological deficits and pathological -Syn accumulation, restoring normal firing patterns, synaptic function, and network activity. Consistent with these observations, EV treatment reduced -Syn aggregation and improved motor responses in -Syn fibril-injected mice, which are characterized by pathological -Syn accumulation and motor deficits. Overall, these findings demonstrate that EVs derived from healthy iPSCs can reverse PD-related phenotypes in human and mouse models.

neuroscience↗

bioRxiv2023

Synaptic dysfunction and dysregulation of extracellular matrix-related genes in dopaminergic neurons derived from Parkinson's disease sporadic patients and with GBA1 mutations

Parkinsons disease (PD) is a neurodegenerative disease with both genetic and sporadic origins. In this study, we investigated the electrophysiological properties, synaptic activity, and gene expression differences in dopaminergic (DA) neurons derived from induced pluripotent stem cells (iPSCs) of healthy controls, sporadic PD (sPD) patients, and PD patients with GBA1 mutations. Our results demonstrate reduced sodium currents and synaptic activity in DA neurons derived from PD patients with GBA1 mutations, suggesting a potential contribution to PD pathophysiology. We also observed distinct electrophysiological alterations in sPD DA neurons that were dependent on the age of disease onset. RNA sequencing analysis revealed unique dysregulated pathways in early and late-onset sPD neurons, further supporting the notion that molecular mechanisms driving PD may be different between PD patients. In agreement with our previous reports, ECM and focal adhesion genes were the top dysregulated pathways in DA neurons from sPD patients and from patients with GBA1 mutations. Overall, this study gives further confirmation that the convergent functional phenotypes of DA neurons derived from PD patients are synaptic abnormalities and at the transcriptome level, ECM and focal adhesion pathways are highly involved in PD pathology across multiple PD-associated mutations as well as sPD.

neuroscience↗

bioRxiv2022

Upregulated extracellular matrix-related genes and impaired synaptic activity in dopaminergic and hippocampal neurons derived from Parkinson's disease patients with PINK1 and PARK2 mutations

Parkinsons disease (PD) is the second most prevalent neurodegenerative disease. Primary symptoms of PD arise with the loss of dopaminergic (DA) neurons in the Substantia Nigra Pars Compacta, but it affects the hippocampus and cortex also, usually in its later stage. Approximately 15% of PD cases familial with a genetic mutation. Two of the most associated genes with autosomal recessive (AR) early-onset familial PD are PINK1 and PARK2. There is a need for in-vitro studies of these genetic mutations in order to understand the neurophysiological changes in patients neurons that may contribute to neurodegeneration. In this work, we generated and differentiated DA and hippocampal neurons from iPSCs derived from two patients with a double mutation in their PINK1 and PARK2 (one homozygous and one heterozygous) genes and assessed their neurophysiology compared to two healthy controls. We showed that the synaptic activity of PD neurons generated from patients with the PINK1 and PARK2 mutations is impaired in the hippocampus and dopaminergic neurons. Mutant dopaminergic neurons had enhanced excitatory post-synaptic activity. In addition, DA neurons with the homozygous mutation of PINK1 exhibited more pronounced electrophysiological differences compared to the control neurons. Signaling network analysis of RNA sequencing results revealed that Focal adhesion and ECM receptor pathway were the top 2 upregulated pathways in the mutant PD neurons. These phenotypes are reversed to PD phenotypes of other mutations, suggesting that the interaction of the two mutations may yield different mechanisms of PD.

neuroscience↗

bioRxiv2022

Reduced synaptic activity and dysregulated extracellular matrix pathways are common phenotypes in midbrain neurons derived from sporadic and mutation-associated Parkinson's disease patients

Several mutations that cause Parkinsons disease (PD) have been identified over the past decade. These account for 15-25% of PD cases; the rest of the cases are considered sporadic. Currently, it is accepted that PD is not a single monolithic disease but rather a constellation of diseases with some common phenotypes. While rodent models exist for some of the PD-causing mutations, research on the sporadic forms of PD is lagging due to a lack of cellular models. In our study, we differentiated PD patient-derived dopaminergic (DA) neurons from induced pluripotent stem cells (iPSCs) of several PD-causing mutations as well as from sporadic PD patients. Strikingly, we observed a common neurophysiological phenotype: Neurons derived from PD patients had a severe reduction in the rate of synaptic currents compared to those derived from healthy controls. While the relationship between mutations in genes such as the SNCA and LRRK2 and a reduction in synaptic transmission has been investigated before, here we show evidence that the pathogenesis of the synapses in neurons is a general phenotype in PD. Analysis of RNA sequencing results displayed changes in gene expression in different synaptic mechanisms as well as other affected pathways such as extracellular matrix-related pathways. Some of these dysregulated pathways are common to all PD patients (monogenic or idiopathic). Our data, therefore, shows changes that are central and convergent to PD and suggests a strong involvement of the tetra-partite synapse in PD pathophysiology.

neuroscience↗

bioRxiv2017

Mitochondrial impairment and rescue in riboflavin responsive neuropathy

Brown-Vialetto-Van Laere syndrome (BVVLS) represents a phenotypic spectrum of motor, sensory, and cranial nerve neuropathy, often with ataxia, optic atrophy and respiratory problems leading to ventilator-dependence. Loss-of-function mutations in two riboflavin transporter (RFVT) genes, SLC52A2 and SLC52A3, have recently been linked to BVVLS. However, the genetic frequency, neuropathology and downstream consequences of RFVT mutations have previously been undefined. By screening a large cohort of 132 patients with early-onset severe sensory, motor and cranial nerve neuropathy we confirmed the strong genetic link between RFVT mutations and BVVLS, identifying twenty-two pathogenic mutations in SLC52A2 and SLC52A3, fourteen of which were novel. Brain and spinal cord neuropathological examination of two cases with SLC52A3 mutations showed classical symmetrical brainstem lesions resembling pathology seen in mitochondrial disease, including severe neuronal loss in the lower cranial nerve nuclei, anterior horns and corresponding nerves, atrophy of the spinothalamic and spinocerebellar tracts and posterior column-medial lemniscus pathways. Mitochondrial dysfunction has previously been implicated in an array of neurodegenerative disorders. Since riboflavin metabolites are critical components of the mitochondrial electron transport chain (ETC), we hypothesized that reduced riboflavin transport would result in impaired mitochondrial activity, and confirmed this using in vitro and in vivo models. ETC complex I and complex II activity were decreased in SLC52A2 patient fibroblasts, while global knockdown of the single Drosophila RFVT homologue revealed reduced levels of riboflavin, downstream metabolites, and ETC complex I activity. RFVT knockdown in Drosophila also resulted in severely impaired locomotor activity and reduced lifespan, mirroring patient pathology, and these phenotypes could be partially rescued using a novel esterified derivative of riboflavin. Our findings indicate mitochondrial dysfunction as a downstream consequence of RFVT gene defects in BVVLS and validate riboflavin esters as a potential therapeutic strategy.

neuroscience↗