Biology subjects

Schneider, B. L.

Publications and source records attributed to Schneider, B. L..

10 recordsLinked to original sources

bioRxiv2025

NATO3 protects dopaminergic neurons in mouse in vivo and human in vitro Parkinson's disease models

Parkinsons disease (PD) is a devastating neurodegenerative disorder primarily characterized by the progressive and unstoppable loss of dopaminergic (DA) neurons in the substantia nigra. We previously identified NATO3 (FERD3L), a conserved developmental transcription factor, as essential for maintaining DA neuron function during aging. Here, we show that AAV-mediated Nato3 gene transfer into the mouse substantia nigra prevents DA neuron degeneration in both MPTP-induced and -synuclein (-Syn) overexpression PD models. This neuroprotective effect is achieved by improving autophagic flux and -Syn clearance. Furthermore, lentiviral-mediated NATO3 overexpression in human midbrain DA neurons, derived from induced pluripotent stem cells carrying the pathological -Syn A53T mutation, effectively reversed key disease hallmarks. These include -Syn accumulation, aberrant mitochondrial morphology, autophagic impairments, and compromised neurite structure. Collectively, these in vivo and in vitro findings highlight NATO3s role in safeguarding DA neurons against pathological cellular events, positioning NATO3 as a therapeutic target for PD.

neuroscience↗

bioRxiv2025

Highly frequent undesired insertional mutagenesis during Drosophila genome editing

CRISPR/Cas9 based genome editing employing Homology Directed Repair (HDR) from template vector sequences is a widely used technique to enable precise insertions, deletions or modifications to genes. Here, we describe an undesired and highly frequent editing event when using conventional CRISPR/Cas9 plus HDR methods for Drosophila melanogaster germline genome editing. We find that the template vector employed for HDR repair unwantedly and commonly inserts into the genome. We observe this deviation from the desired edit at multiple genomic locations, with different HDR vectors and with multiple genome editing designs. To avoid these events, we have generated a novel HDR template vector that enables animals with these undesired insertions to be identified and excluded. Our results suggest that HDR based genome edited animals must be carefully screened for unwanted vector template genomic integration in order to avoid misleading interpretations of genome editing outcomes.

molecular biology↗

bioRxiv2025

Mifepristone alone and in combination with scAAV9-SMN1 gene therapy improves disease phenotypes in Smn2B/- spinal muscular atrophy mice

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by deletions or mutations in the survival motor neuron 1 (SMN1) gene. SMA is characterised by alpha motor neuron loss in the spinal cord and subsequent muscle atrophy. There are currently three approved SMN-directed therapies for SMA patients. While these therapies have transformed what was once a life-limiting condition into one that can be managed and even improved, they are unfortunately not cures, highlighting the need for additional supporting second-generation therapies. These should not only target the neuromuscular system but also peripheral and metabolic perturbations that are present in both SMA models and patients. Kruppel-like factor 15 (Klf15) is a transcription factor that maintains metabolic homeostasis and is involved in the glucocorticoid-glucocorticoid receptor (GR) signalling pathway, in several peripheral and metabolic tissues in SMA mice. Here, we used murine and human cellular models as well as SMA mice and Caenorhabditis Elegans (C. elegans) to assess the therapeutic potential of reducing Klf15 activity with mifepristone, a glucocorticoid antagonist, combined with SMN-targeted gene therapy. We report that mifepristone reduces Klf15 expression across several in vitro models, ameliorates neuromuscular pathology in SMA smn-1(ok355) C. elegans and improves survival of SMA Smn2B/- mice. Furthermore, we show that combining mifepristone with an approved SMN-directed gene therapy (scAAV9-SMN1) results in improved tissue- and sex-specific responses to treatment. Our study demonstrates that a multi-tissue targeting SMN-independent drug, alone and in combination with an approved SMN-dependent therapy, has the potential to improve SMA disease pathology.

pharmacology and toxicology↗

bioRxiv2022

Rapid ex vivo reverse genetics identifies the essential determinants of prion protein toxicity

The cellular prion protein PrPC mediates the neurotoxicity of prions and other protein aggregates through poorly understood mechanisms. Antibody-derived ligands against the globular domain of PrPC (GDL) can also initiate neurotoxicity by inducing an intramolecular R208-H140 hydrogen bond ("H-latch") between the 2-3 and {beta}2-2 loops of PrPC. Importantly, GDL that suppress the H-latch prolong the life of prion-infected mice, suggesting that GDL toxicity and prion infections exploit convergent pathways. To define the structural underpinnings of these phenomena, we transduced nineteen individual PrPC variants to PrPC-deficient cerebellar organotypic cultured slices using adenovirus-associated viral vectors (AAV). We report that GDL toxicity requires a single N-proximal cationic residue (K27 or R27) within PrPC. Alanine substitution of K27 also prevented the toxicity of PrPC mutants that induce Shmerling syndrome, a neurodegenerative disease that is suppressed by co-expression of wild-type PrPC. K27 may represent an actionable target for compounds aimed at preventing prion-related neurodegeneration.

neuroscience↗

bioRxiv2022

Mitofusin-2 in nucleus accumbens D2-MSNs regulates social dominance and neuronal function

The nucleus accumbens (NAc) is a brain hub regulating motivated behaviors, including social competitiveness. Mitochondrial function in the NAc is critically implicated in the association between anxiety and social competitiveness, and the mitochondrial fusion protein mitofusin 2 (Mfn2) in NAc neurons has been shown to regulate anxiety-related behaviors. However, it remains unexplored whether accumbal Mfn2 levels also affect social behavior and whether Mfn2 actions in the emotional and social domain are driven by distinct cell types. Here, we found that subordinate-prone highly anxious rats show reduced accumbal Mfn2 levels and that Mfn2 overexpression promotes dominant behavior. In mice, selective Mfn2 downregulation in NAc dopamine D2 receptor-expressing medium spiny neurons (D2-MSNs) induced social subordination, accompanied by reduced mitochondrial function and decreased neuronal excitability. Instead, D1-MSN-targeted Mfn2 downregulation affected competitive ability only transiently mainly by increases in anxiety-like behaviors. Our results assign dissociable cell-type specific roles to Mfn2 in the NAc in modulating social dominance and anxiety.

neuroscience↗

bioRxiv2022

Differential effect of Fas activation on spinal muscular atrophy motoneuron death and induction of axonal growth

Amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA) are the most common motoneuron diseases affecting adults and infants, respectively. ALS and SMA are both characterized by the selective degeneration of motoneurons. Although different in their genetic etiology, growing evidence indicate that they share molecular and cellular pathogenic signatures that constitute potential common therapeutic targets. We previously described a motoneuron-specific death pathway elicited by the Fas death receptor, whereby vulnerable ALS motoneurons show an exacerbated sensitivity to Fas activation. However, the mechanisms that drive the loss of SMA motoneurons remains poorly understood. Here, we describe an in vitro model of SMA-associated degeneration using primary motoneurons derived from Smn2B/- SMA mice and show that Fas activation selectively triggers death of the proximal motoneurons. Fas-induced death of SMA motoneurons has the molecular signature of the motoneuron-selective Fas death pathway that requires activation of p38 kinase, caspase-8, -9 and -3 as well as upregulation of collapsin response mediator protein 4 (CRMP4). In addition, Rho Kinase (ROCK) is required for Fas recruitment. Remarkably, we found that exogenous activation of Fas also promotes axonal elongation in both wildtype and SMA motoneurons. Axon outgrowth of motoneurons promoted by Fas requires the activity of ERK, ROCK and caspases. This work defines a dual role of Fas signaling in motoneurons that can elicit distinct responses from cell death to axonal growth.

neuroscience↗

bioRxiv2021

Central and peripheral delivery of AAV9-SMN target different pathomechanisms in a mouse model of spinal muscular atrophy

Spinal muscular atrophy (SMA) is a neuromuscular disease caused by loss of the SMN1 gene. Although lower motor neurons are a primary target, there is evidence that peripheral organ defects contribute to SMA. Current SMA gene therapy uses a single, high titre intravenous bolus of AAV9-SMN resulting in impressive, yet limited amelioration of the clinical phenotype. However, risks of this treatment include liver toxicity. Intrathecal administration is under clinical trial but was interrupted due to safety concerns in a concomitant animal study. As there is no direct comparison between the different delivery strategies while avoiding high dose toxicity, we injected SMA mice with low dose scAAV9-cba-SMN either intravenously (IV) for peripheral SMN restoration or intracerebroventricularly (ICV) for CNS-focused SMN restoration. Here, IV injections restored SMN in peripheral tissues but not CNS, while ICV injections mildly increased SMN in the periphery and the CNS. Consequently, only ICV treatment rescued motor neuron degeneration. Surprisingly, both treatments resulted in an impressive rescue of survival, weight, motor function, and peripheral phenotypes including liver and pancreas pathology. Our work highlights independent contributions of peripheral organs to SMA pathology and suggests that treatments should not be restricted to the motor neuron. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=148 SRC="FIGDIR/small/467795v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@1e4e882org.highwire.dtl.DTLVardef@15ccf93org.highwire.dtl.DTLVardef@3fe393org.highwire.dtl.DTLVardef@75cc20_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2021

Expression of a miRNA targeting mutated SOD1 in astrocytes induces motoneuron plasticity and improves neuromuscular function in ALS mice

In amyotrophic lateral sclerosis (ALS) caused by SOD1 gene mutations, both cell-autonomous and non-cell-autonomous mechanisms lead to the selective degeneration of motoneurons. Here, we evaluate the therapeutic potential of gene therapy targeting mutated SOD1 in mature astrocytes using mice expressing the mutated SOD1G93A protein. An AAV-gfaABC1D vector encoding an artificial microRNA is used to deliver RNA interference against mutated SOD1 selectively in astrocytes. The treatment leads to the progressive rescue of neuromuscular junction occupancy, to the recovery of the compound muscle action potential in the gastrocnemius muscle, and significantly improves neuromuscular function. In the spinal cord, gene therapy targeting astrocytes protects a small pool of fast-fatigable motoneurons until disease end stage. In the gastrocnemius muscle of the treated SOD1G93A mice, the fast-twitch type IIb muscle fibers are preserved from atrophy. Axon collateral sprouting is observed together with muscle fiber type grouping indicative of denervation/re-innervation events. The transcriptome profiling of spinal cord motoneurons shows changes in the expression levels of factors regulating the dynamics of microtubules. Gene therapy delivering RNA interference against mutated SOD1 in astrocytes provides therapeutic effects enhancing motoneuron plasticity and improving neuromuscular function in ALS mice.

neuroscience↗

bioRxiv2020

PARKIN REGULATES DRUG TAKING-BEHAVIOR IN RAT MODEL OF METHAMPHETAMINE USE DISORDER

There is no FDA-approved medication for Methamphetamine (METH) Use Disorder. New therapeutic approaches are needed, especially for people who use METH heavily and are at high risk for overdose. This study used genetically engineered rats to evaluate PARKIN as a potential target for METH Use Disorder. PARKIN knockout, PARKIN-overexpressing and wild-type young adult male Long Evans rats were trained to self-administer high doses of METH using an extended-access METH self-administration paradigm. Reinforcing/rewarding properties of METH were assessed by quantifying drug-taking behavior and time spent in a METH-paired environment. PARKIN knockout rats self-administered more METH and spent more time in the METH-paired environment than wild-type rats. Wild-type rats overexpressing PARKIN self-administered less METH and spent less time in the METH-paired environment. PARKIN knockout rats overexpressing PARKIN self-administered less METH during the first half of drug self-administration days than PARKIN-deficient rats. The results indicate that rats with PARKIN excess or PARKIN deficit are useful models for studying neural substrates underlying "resilience" or vulnerability to METH Use Disorder, and identify PARKIN as a novel potential drug target to treat heavy use of METH.

neuroscience↗

bioRxiv2020

A mouse model for spinal muscular atrophy provides insights into non-alcoholic fatty liver disease pathogenesis

Background & aims Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder leading to paralysis and death in children. SMA patients are more susceptible to dyslipidemia as well as liver steatosis, features reproduced in SMA mouse models. As current pre-clinical models of NAFLD are invariably imperfect and generally take a long time to develop, the rapid development of liver steatosis in SMA mice provides a means to identify molecular markers of non-alcoholic fatty liver disease (NAFLD). Here, we investigated whether Smn2B/- mice, a model of severe SMA, display typical features of NAFLD/non-alcoholic steatohepatitis (NASH).Methods Biochemical, histological, electron microscopy, proteomic, and high-resolution respirometry were used.Results The Smn2B/- mice develop steatohepatitis early in life. The consequent liver damage arises from mitochondrial reactive oxygen species production and results in impaired hepatic function including alterations in protein output, complement, coagulation, iron homeostasis, and IGF-1 metabolism. The steatohepatitis is reversible by AAV9-SMN gene therapy. The NAFLD phenotype is likely due to non-esterified fatty acid (NEFA) overload from peripheral lipolysis, subsequent to hyperglucagonemia compounded by reduced muscle use. Mitochondrial β-oxidation contributed to hepatic damage as we observed enhanced hepatic mitochondrial β-oxidation and reactive oxygen species production. Hepatic mitochondrial content, however, was decreased. In contrast to typical NAFLD/NASH, the Smn2B/- mice lose weight due to their neurological condition, develop hypoglycemia and do not develop hepatic fibrosis.Conclusion The Smn2B/- mice represent a good model of microvesicular steatohepatitis. Like other models, it is not representative of the complete NAFLD/NASH spectrum. Nevertheless, it offers a reliable, low-cost, early onset model that is not dependent on diet to identify molecular players in NAFLD pathogenesis and can serve as one of the very few models of microvesicular steatohepatitis for both adult and pediatric populations.Competing Interest StatementMarc-Olivier Deguise received honoraria and travel accommodations from Biogen for speaking engagements at the SMA Summit 2018 held in Montreal, Canada and SMA Academy 2019 held in Toronto, Canada. Rashmi Kothary received honoraria and travel accommodations from Roche as an invited speaker at their global and national board meetings in 2019. RK and the Ottawa Hospital Research Institute have a licensing agreement with Biogen for the Smn2B/- mouse model. Thomas H. Gillingwater has served on global and UK advisory boards for Roche. These COI are outside the scope of this study. All other authors have no competing interests to declare.List of abbreviationsAGCautomatic gain controlALPalkaline phosphataseALTalanine aminotransferaseASTaspartate aminotransferaseBaxBCL2 associated X proteinDAVIDThe Database for Annotation, Visualization and Integrated DiscoveryESEnrichment ScoreFasRFas receptorH&EHematoxylin & eosinHFDhigh fat dietIGF-1insulin-like growth factor 1IGFbp1insulin like growth factor binding protein 1IGF1Rinsulin like growth factor 1 receptorigfalsinsulin like growth factor binding protein acid labile subunitIPAingenuity pathway analysisMCDmethionine and choline deficient dietMCLMarkov Clustering AlgorithmNAFLDnon-alcoholic fatty liver diseaseNASHnon-alcoholic steatohepatitisNEFAnon-esterified fatty acidPpostnatal dayp21cyclin dependent kinase inhibitor 1Ap53tumor protein p53PASPeriodic acid-SchiffSMAspinal muscular atrophySMN1Survival motor neuron 1TMTTandem Mass TaggingTNFR1TNF receptor superfamily member 1AView Full Text

pathology↗