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Nagoshi, E.

Publications and source records attributed to Nagoshi, E..

11 recordsLinked to original sources

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↗

Circadian control of dopaminergic signaling to the mushroom body regulates sleep through rhythmic Pka-C1 transcription in Drosophila

Despite the progress in understanding the circadian pacemaker, the specific mechanism by which it regulates sleep remains incompletely understood. We have previously demonstrated that a substantial number of genes are rhythmically expressed in the mushroom body (MB) Kenyon cells (KCs), including Pka-C1, which encodes the catalytic subunit of protein kinase A (PKA). PKA-C1 plays a crucial role in promoting daytime wakefulness; however, the underlying mechanism remains elusive. Here, we show that the {gamma}-lobe is the primary site of rhythmic Pka-C1 expression using a newly developed in vivo luciferase reporter. Through a combination of in silico analysis, CRISPR mutagenesis, and chromatin immunoprecipitation, we identify the transcription factor Onecut as a regulator of Pka-C1 transcriptional rhythms in {gamma}-KCs. Furthermore, genetic trans-synaptic connectivity mapping and neuronal activity imaging reveal that the dorsal Lateral clock Neurons (LNds) provide inhibitory input to a subset of dopaminergic (DA) neurons in the protocerebral anterior medial (PAM) cluster, PAM-{gamma}5, rhythmically modulating their activity. This, in turn, rhythmically activates MB {gamma}-KCs via excitatory Dop1R signaling. Resulting {gamma}-neuron activity rhythms drive Pka-C1 transcriptional rhythms through Onecut. Furthermore, these PKA-C1 rhythms reinforce neuronal activity rhythms, creating a feedback cycle between transcriptional and neural activity rhythms that promote daytime wakefulness. Our findings highlight the conserved role of DA in promoting wakefulness and offer mechanistic insights into its complex regulation. More generally, this work provides a mechanistic framework for how circadian rhythms are translated into neural activity to orchestrate complex behaviors like sleep.

neuroscience↗

Characterization of the Post-Mating Responses of Drosophila hydei, a species that lacks Sex-Peptide.

Female post-mating responses (PMRs) in Drosophila melanogaster rely on proteins made by the male that are transferred to the female upon mating to modify her behavior and physiology. Many of the most characterized responses are initiated by a single protein produced by the male accessory gland called the Sex Peptide (SP). Yet many Drosophila species, even those living in similar environments, do not have SP. As PMRs are thought to be mechanisms used to maximize reproductive success, we wondered if PMRs are similar in species living in the same environment and how PMRs might be achieved in species that lack SP. Here, we investigate the post-mating responses of D. hydei. D. hydei is a Drosophilid that lacks SP, but is often found cohabitating with D. melanogaster. We show that the PMR in D. hydei is markedly different from that found in D. melanogaster; D. hydei do not increase egg production, nor do they limit remating to additional males or change their diet after mating. Instead, hydei seem to display only subtle PMRs related to activity patterns, in a way distinct from those characterized in D. melanogaster. These changes seem to have impacted things like lifespan and sperm selection, and demonstrate the wide variety of choices that species can make and be successful in a given environment.

evolutionary biology↗

Drosophila Video-assisted Activity Monitor (DrosoVAM): a versatile method for behavior monitoring

Drosophila melanogaster has been a pioneering model system for investigations into the genetic bases of behavior. Studies of circadian activity were some of the first behaviors investigated in flies. The DAM system by TriKinetics played a key role in establishing the fundamental feedback loop of the circadian clock. Although this method has many time proven to be extremely useful, it suffers from its simplification of activity to the interruption of an infrared beam. It is blind to fly movements not disrupting the beam and any modifications to this assay to achieve better resolution often requires the purchase of new and expensive modules. We required a relatively high-throughput system to explore the potential post-mating activity changes of larger Drosophila species. Rather than investing in a larger and more-complex DAM system, we designed a new monitoring system that is more versatile, economic and sensitive than DAM. This new system, called DrosoVAM (Drosophila Video-assisted Activity Monitoring), is simple to implement and cost efficient, using a Raspberry Pi-controlled infrared, digital video system to record multiple chambers and Python scripts that drives the deep learning software DeepLabCut, to track fly activity over multiple days.

animal behavior and cognition↗

Examining the potential involvement of NONO in TDP-43 proteinopathy in Drosophila

The misfolding and aggregation of TAR DNA binding protein-43 (TDP-43), leading to the formation of cytoplasmic inclusions, emerge as a key pathological feature in a spectrum of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD). TDP-43 shuttles between the nucleus and cytoplasm but forms nuclear bodies (NBs) in response to stress. These NBs partially colocalize with nuclear speckles and paraspeckles that sequester RNAs and proteins, thereby regulating many cellular functions. The laboratory of Steven Brown has recently found that the non-POU domain-containing octamer-binding protein (NONO), a component of paraspeckles, forms novel nuclear speckle-like structures in mouse cortical neurons in response to stress and sleep deprivation. These findings suggest the possibility of a functional link between NONO and TDP-43, potentially contributing to TDP-43 proteinopathy. Here, we demonstrate that loss of function in the Drosophila homolog of NONO, no on or off transient A (NonA), exacerbates pathological phenotypes caused by TDP-43 gain of function, leading to locomotor defects and life span shortening. These results provide supporting evidence for the functional link between NONO and TDP-43 and lay the foundation for dissecting underlying mechanisms.

neuroscience↗

Evolution of circadian behavioral plasticity through cis-regulatory divergence of a neuropeptide gene

Widely-distributed species experience substantial environmental variation, which they often accommodate through behavioral plasticity. Although this ability is integral to fitness, we have little understanding of the mechanistic basis by which plasticity evolves. One factor that varies seasonally and by latitude is photoperiod (day length). Many organisms, including the cosmopolitan Drosophila melanogaster display circadian plasticity, adjusting to fluctuating photoperiod by varying the timing of their activity to coincide with changing dawn/dusk intervals1. Here, we compare D. melanogaster with the closely-related ecological specialist Drosophila sechellia, an equatorial island endemic that experiences minimal photoperiod variation, to investigate the molecular-genetic basis of circadian plasticity evolution2,3. We discover that D. sechellia displays exceptionally little circadian plasticity compared to D. melanogaster and other non-equatorial drosophilids. Through a screen of circadian mutants in D. melanogaster/D. sechellia hybrids, we identify a role of the neuropeptide Pigment-dispersing factor (Pdf) in this loss. While the coding sequence of Pdf is conserved, we show that Pdf has undergone cis-regulatory divergence in these drosophilids. We document species-specific temporal dynamic properties of Pdf RNA and protein expression, as well as Pdf neuron morphological plasticity, and demonstrate that modulating Pdf expression in D. melanogaster can influence the degree of behavioral plasticity. Furthermore, we find that the Pdf regulatory region exhibits signals of selection across populations of D. melanogaster from different latitudes. Finally, we provide evidence that plasticity confers a selective advantage for D. melanogaster at higher latitudes, while D. sechellia likely suffers fitness costs through reduced copulation success outside its range. Our work defines Pdf as a locus of evolution for circadian plasticity, which might have contributed to both D. melanogasters global distribution and D. sechellias habitat specialization. Moreover, together with spatial changes in Pdf expression reported in high-latitude drosophilid species4,5, our findings highlight this neuropeptide gene as a hotspot for circadian plasticity evolution.

evolutionary biology↗

The utility and caveat of split-GAL4s in the study of neurodegeneration

Parkinsons disease (PD) is the second most common neurodegenerative disorder, afflicting over 1% of the population of age 60 years and above. The loss of dopaminergic (DA) neurons is the substantia nigra pars compacta (SNpc) is the primary cause of its characteristic motor symptoms. Studies using Drosophila melanogaster and other model systems have provided much insight into the pathogenesis of PD. However, little is known why certain cell types are selectively susceptible to degeneration in PD. Here we describe an approach to identify vulnerable subpopulations of neurons in the genetic background linked to PD in Drosophila, using the split-GAL4 divers that enable genetic manipulation of a small number of defined cell population. We identify a subtype of DA neurons selectively vulnerable in the model of the leucine-rich repeat kinase 2 (LRRK2)-linked familial PD, demonstrating the utility of this approach. We also show an unexpected caveat of the split-GAL4 system in aging-related research: the age-dependent increase in the number of GAL4-labeled cells.

neuroscience↗

Circadian clock disruption promotes the degeneration of dopaminergic neurons

Sleep and circadian rhythm disruptions are frequent comorbidities of Parkinsons disease (PD), a disorder characterized by the progressive loss of dopaminergic (DA) neurons in the substantia nigra. Although sleep/circadian disturbances can be observed years before diagnosing PD, it remains unclear whether circadian clocks have a causal role in the degenerative process. We demonstrated here that circadian clocks regulate the rhythmicity and magnitude of the vulnerability of DA neurons to oxidative stress in Drosophila. Circadian pacemaker neurons are presynaptic to a subset of DA neurons and rhythmically modulate their susceptibility to degeneration. The arrhythmic period (per) gene null mutation exacerbates the age-dependent loss of DA neurons and, in combination with brief oxidative stress, causes premature animal death. These findings suggest that circadian clock disruption promotes dopaminergic neurodegeneration.

neuroscience↗

Rhythmic expression of Neurofibromin 1 in mushroom body neurons mediates circadian wake drive through activating cAMP-PKA signaling

Various behavioral and cognitive states exhibit circadian variations in animals across phyla including Drosophila, in which only [~]0.1% of the entire brain neurons contain circadian clocks. This suggests that clock neurons communicate with a plethora of non-clock neurons to transmit the timing information to gate various behavioral outputs in Drosophila. Here, we address the molecular underpinning of this phenomenon by performing circadian RNA-seq analysis of non-clock neurons that constitute the mushroom body (MB), the center of information processing and sleep regulation. We identify hundreds of genes rhythmically expressed in the MB, including the Drosophila ortholog of Neurofibromin 1 (Nf1), the gene responsible for neurofibromatosis type 1 (NF1). Rhythmic expression of Nf1 promotes daytime wakefulness by activating cAMP-PKA signaling and increasing excitability of the MB. These findings reveal the pervasive, non-cell-autonomous circadian regulation of gene expression in the brain and its role in sleep, with implications in the pathology of NF1.

neuroscience↗

Maintenance of mitochondrial integrity in midbrain dopaminergic neurons governed by a conserved developmental transcription factor

The degeneration of dopaminergic (DA) neurons in the substantia nigra is a hallmark of Parkinsons disease (PD). Dysregulation of developmental transcription factors is implicated in dopaminergic neurodegeneration, but the underlying molecular mechanisms remain largely unknown. Drosophila Fer2 is a prime example of a developmental transcription factor required for the birth and maintenance of midbrain DA neurons. Using an approach combining ChIP-seq, RNA-seq, and genetic epistasis experiments with PD-linked genes, here we demonstrate that Fer2 controls a transcriptional network to maintain mitochondrial structure and function, and thus confers dopaminergic neuroprotection against genetic and oxidative insults. We further show that conditional ablation of Nato3, a mouse homolog of Fer2, in differentiated DA neurons results in locomotor impairments and mitochondrial abnormality in aged mice. Our results reveal the essential and conserved role of Fer2 homologs in the mitochondrial maintenance of midbrain DA neurons, opening new perspectives for modelling and treating PD.

neuroscience↗

Nitric Oxide Mediates Neuro-Glial Interaction that Shapes Drosophila Circadian Behavior

Drosophila circadian behavior relies on the network of heterogeneous groups of clock neurons. Short -and long-range signaling within the pacemaker circuit coordinates molecular and neural rhythms of clock neurons to generate coherent behavioral output. The neurochemistry of circadian behavior is complex and remains incompletely understood. Here we demonstrate that the gaseous messenger nitric oxide (NO) is a signaling molecule linking circadian pacemaker to rhythmic locomotor activity. We show that two independent mutants lacking nitric oxide synthase (NOS) have severely disturbed locomotor behavior both in light-dark cycles and constant darkness, although molecular clocks in the main pacemaker neurons are unaffected. Behavioral phenotypes are due in part to the malformation of neurites of the main pacemaker neurons, s-LNvs. Using cell-type selective and stage-specific gain -and loss-of-function of NOS, we demonstrate that NO secreted from diverse cellular clusters non-cell-autonomously affect molecular and behavioral rhythms. We further identify glia as a major source of NO that regulates circadian locomotor output. These results reveal for the first time the critical role of NO signaling in the Drosophila circadian system and highlight the importance of neuro-glial interaction in the neural circuit output.\n\nAuthor summaryCircadian rhythms are daily cycles of physiological and behavioral processes found in most plants and animals on our planet from cyanobacteria to humans. Circadian rhythms allow organisms to anticipate routine daily and annual changes of environmental conditions and efficiently adapt to them. Fruit fly Drosophila melanogaster is an excellent model to study this phenomenon, as its versatile toolkit enables the study of genetic, molecular and neuronal mechanisms of rhythm generation. Here we report for the first time that gasotransmitter nitric oxide (NO) has a broad, multi-faceted impact on Drosophila circadian rhythms, which takes place both during the development and the adulthood. We also show that one of the important contributors of NO to circadian rhythms are glial cells. The second finding highlights that circadian rhythms of higher organisms are not simply controlled by the small number of pacemaker neurons but are generated by the system that consists of many different players, including glia.

neuroscience↗