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Jagasia, R.

Publications and source records attributed to Jagasia, R..

3 recordsLinked to original sources
bioRxiv2022

Angelman syndrome patient neuron screen identifies a potent and selective clinical ASO targeting UBE3A-ATS with long lasting effect in cynomolgus monkey

Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by the loss of neuronal E3 ligase UBE3A with no available treatment. Restoring UBE3A levels via downregulation of the paternally cis-acting long non-coding antisense transcript (UBE3A-ATS) is a potential disease modifying. Developing molecules targeting human UBE3A-ATS is challenging because it is expressed only in neurons and lacks animal species sequence conservation. To overcome this, we performed a library screen of locked-nucleic acid (LNA)-modified antisense oligonucleotides (ASOs) on AS patient-derived neurons, identifying initial sequences. Further optimization led to the identification of the ASO, RO7248824, which selectively and potently reduces UBE3A-ATS, while concomitantly upregulating the UBE3A mRNA and protein. These properties held true in both human AS patient- and neurotypical-, as well as cynomolgus monkey-derived neurons. In vivo use of tool molecules in wild-type (WT) and AS Ube3am-/p+ mice, revealed a steep relationship between UBE3A-ATS knock-down and UBE3A mRNA/protein upregulation, whereby an almost 90% downregulation was needed to achieve a 50% upregulation, respectively. This relationship was confirmed in cynomolgus monkeys. Whereby, repeated lumbar intrathecal administrations of RO7248824 was well tolerated without adverse in-life effects or tissue pathology and produced a robust, long lasting (up to 3 months) paternal reactivation of UBE3A mRNA/protein across key monkey brain regions. Our results demonstrate that AS human pluripotent stem cell neurons serve as an excellent translational tool and furthermore LNA-modified ASOs exhibit excellent drug-like properties. Sustained efficacy translated to infrequent, intrathecal dosing and serves as the basis for the ongoing clinical development of RO7248824 for AS. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=131 SRC="FIGDIR/small/495066v1_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@1c2a97eorg.highwire.dtl.DTLVardef@1059954org.highwire.dtl.DTLVardef@95835aorg.highwire.dtl.DTLVardef@1e2adea_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical abstract.C_FLOATNO From AS patient blood to a neuronal screen, identifies clinical ASO with excellent in vivo properties. (1) Patients were recruited. (2) Whereby blood was reprogrammed into hIPSC and subsequently differentiated into neurons. (3) ASOs were designed and screened on human neurons to downregulate the UBE3A-ATS likely via directed RNase H Cleavage of Nascent Transcripts. (4a) RO7248824 was identified that potently and selective reduces UBE3A-ATS, concomitantly with upregulating the UBE3A sense transcript and protein which was used for in vitro pk/pd. (4b) In parallel tool murine ASO were used demonstrate in vivo POC.(5) Pivotal nonhuman primate studies to monitor safety and predict the human dose. (6) RO7248824 is in AS clinical trial. C_FIG One Sentence SummaryFrom angelman syndrome human neuron screen to cynomolgus monkey proof of concept identifies the clinical molecule RO7248824

neuroscience↗
bioRxiv2022

Downregulating α-synuclein in iPSC-derived dopaminergic neurons mimics electrophysiological phenotype of the A53T mutation

Parkinsons disease (PD) is a common debilitating neurodegenerative disorder, characterized by a progressive loss of dopaminergic (DA) neurons. Mutations, gene dosage increase, and single nucleotide polymorphisms in the -synuclein-encoding gene SNCA either cause or increase the risk for PD. However, neither the function of -synuclein in health and disease, nor its role throughout development is fully understood. Here, we introduce DeePhys, a new tool that allows for data-driven functional phenotyping of neuronal cell lines by combining electrophysiological features inferred from high-density microelectrode array (HD-MEA) recordings with a robust machine learning workflow. We apply DeePhys to human induced pluripotent stem cell (iPSC)-derived DA neuron-astrocyte co-cultures harboring the prominent SNCA mutation A53T and an isogenic control line. Moreover, we demonstrate how DeePhys can facilitate the assessment of cellular and network-level electrophysiological features to build functional phenotypes and to evaluate potential treatment interventions. We find that electrophysiological features across all scales proved to be highly specific for the A53T phenotype, enabled to predict the genotype and age of individual cultures with high accuracy, and revealed a mutant-like phenotype after downregulation of -synuclein.

neuroscience↗
bioRxiv2022

Homophilic wiring principles underpin neuronal network topology in vitro

Economic efficiency has been a popular explanation for how networks self-organize within the developing nervous system. However, the precise nature of the economic negotiations governing this putative organizational principle remains unclear. Here, we address this question further by combining large-scale electrophysiological recordings, to characterize the functional connectivity of developing neuronal networks in vitro, with a generative modeling approach capable of simulating network formation. We find that the best fitting model uses a homophilic generative wiring principle in which neurons form connections to other neurons which are spatially proximal and have similar connectivity patterns to themselves. Homophilic generative models outperform more canonical models in which neurons wire depending upon their spatial proximity either alone or in combination with the extent of their local connectivity. This homophily-based mechanism for neuronal network emergence accounts for a wide range of observations that are described, but not sufficiently explained, by traditional analyses of network topology. Using rodent and human monolayer and organoid cultures, we show that homophilic generative mechanisms can accurately recapitulate the topology of emerging cellular functional connectivity, representing an important wiring principle and determining factor of neuronal network formation in vitro.

neuroscience↗