scholarly journals A Drosophila model of Fragile X syndrome exhibits defects in phagocytosis by innate immune cells

2017 ◽  
Vol 216 (3) ◽  
pp. 595-605 ◽  
Author(s):  
Reed M. O’Connor ◽  
Elizabeth F. Stone ◽  
Charlotte R. Wayne ◽  
Emily V. Marcinkevicius ◽  
Matt Ulgherait ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Immune Cells ◽  
Rna Binding ◽  
Fragile X ◽  
The Body ◽  
Innate Immune ◽  
Drosophila Model ◽  
A Cell ◽  
Increased Sensitivity ◽  
The Brain

Fragile X syndrome, the most common known monogenic cause of autism, results from the loss of FMR1, a conserved, ubiquitously expressed RNA-binding protein. Recent evidence suggests that Fragile X syndrome and other types of autism are associated with immune system defects. We found that Drosophila melanogaster Fmr1 mutants exhibit increased sensitivity to bacterial infection and decreased phagocytosis of bacteria by systemic immune cells. Using tissue-specific RNAi-mediated knockdown, we showed that Fmr1 plays a cell-autonomous role in the phagocytosis of bacteria. Fmr1 mutants also exhibit delays in two processes that require phagocytosis by glial cells, the immune cells in the brain: neuronal clearance after injury in adults and the development of the mushroom body, a brain structure required for learning and memory. Delayed neuronal clearance is associated with reduced recruitment of activated glia to the site of injury. These results suggest a previously unrecognized role for Fmr1 in regulating the activation of phagocytic immune cells both in the body and the brain.

scholarly journals Pioglitazone improves deficits of Fmr1-KO mouse model of Fragile X syndrome by interfering with excessive diacylglycerol signaling

2020 ◽  
Author(s):  
Andréa Geoffroy ◽  
Karima Habbas ◽  
Boglarka Zambo ◽  
Laetitia Schramm ◽  
Arnaud Duchon ◽  
...  
Keyword(s):  
Mouse Model ◽  
Fragile X Syndrome ◽  
Rna Binding ◽  
Fragile X ◽  
Loss Of Function ◽  
Behavioral Alterations ◽  
Specific Proteins ◽  
The Brain

AbstractFragile X syndrome (FXS), the leading cause of familial intellectual disability, is an uncured disease caused by the absence or loss of function of the FMRP protein. FMRP is an RNA binding protein that controls the translation of specific proteins in neurons. A main target of FMRP in neurons is diacylglycerol kinase kappa (DGKk) and the loss of FMRP leads to a loss of DGK activity causing a diacylglycerol excess in the brain. Excessive diacylglycerol signaling could be a significant contributor to the pathomechanism of FXS. Here we tested the contribution of DAG-signaling in Fmr1-KO mouse model of FXS and we show that pioglitazone, a widely prescribed drug for type 2 diabetes, has ability to correct excessive DAG signaling in the brain and rescue behavioral alterations of the Fmr1-KO mouse. This study highlights the role of lipid signaling homeostasis in FXS and provides arguments to support the testing of pioglitazone for treatment of FXS.

Involvement of Phosphodiesterase 2A Activity in the Pathophysiology of Fragile X Syndrome

2018 ◽  
Vol 29 (8) ◽  
pp. 3241-3252 ◽  
Author(s):  
Thomas Maurin ◽  
Francesca Melancia ◽  
Marielle Jarjat ◽  
Liliana Castro ◽  
Lara Costa ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Translational Regulation ◽  
Rna Binding ◽  
Fragile X ◽  
The Social ◽  
Mental Retardation Protein ◽  
Camp And Cgmp ◽  
The Brain

Abstract The fragile X mental retardation protein (FMRP) is an RNA-binding protein involved in translational regulation of mRNAs that play key roles in synaptic morphology and plasticity. The functional absence of FMRP causes the fragile X syndrome (FXS), the most common form of inherited intellectual disability and the most common monogenic cause of autism. No effective treatment is available for FXS. We recently identified the Phosphodiesterase 2A (Pde2a) mRNA as a prominent target of FMRP. PDE2A enzymatic activity is increased in the brain of Fmr1-KO mice, a recognized model of FXS, leading to decreased levels of cAMP and cGMP. Here, we pharmacologically inhibited PDE2A in Fmr1-KO mice and observed a rescue both of the maturity of dendritic spines and of the exaggerated hippocampal mGluR-dependent long-term depression. Remarkably, PDE2A blockade rescued the social and communicative deficits of both mouse and rat Fmr1-KO animals. Importantly, chronic inhibition of PDE2A in newborn Fmr1-KO mice followed by a washout interval, resulted in the rescue of the altered social behavior observed in adolescent mice. Altogether, these results reveal the key role of PDE2A in the physiopathology of FXS and suggest that its pharmacological inhibition represents a novel therapeutic approach for FXS.

scholarly journals Power Failure of Mitochondria and Oxidative Stress in Neurodegeneration and Its Computational Models

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 229
Author(s):  
JunHyuk Woo ◽  
Hyesun Cho ◽  
YunHee Seol ◽  
Soon Ho Kim ◽  
Chanhyeok Park ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Dysfunction ◽  
Computational Models ◽  
Neuronal Damage ◽  
Living Organism ◽  
The Body ◽  
Mitochondrial Functions ◽  
A Cell ◽  
The Brain ◽  
And Oxidative Stress

The brain needs more energy than other organs in the body. Mitochondria are the generator of vital power in the living organism. Not only do mitochondria sense signals from the outside of a cell, but they also orchestrate the cascade of subcellular events by supplying adenosine-5′-triphosphate (ATP), the biochemical energy. It is known that impaired mitochondrial function and oxidative stress contribute or lead to neuronal damage and degeneration of the brain. This mini-review focuses on addressing how mitochondrial dysfunction and oxidative stress are associated with the pathogenesis of neurodegenerative disorders including Alzheimer’s disease, amyotrophic lateral sclerosis, Huntington’s disease, and Parkinson’s disease. In addition, we discuss state-of-the-art computational models of mitochondrial functions in relation to oxidative stress and neurodegeneration. Together, a better understanding of brain disease-specific mitochondrial dysfunction and oxidative stress can pave the way to developing antioxidant therapeutic strategies to ameliorate neuronal activity and prevent neurodegeneration.

scholarly journals Fragile X syndrome patient-derived neurons developing in the mouse brain show FMR1 -dependent phenotypes

2021 ◽  
Author(s):  
Marine A Krzisch ◽  
Hao A Wu ◽  
Bingbing Yuan ◽  
Troy W. Whitfield ◽  
X. Shawn Liu ◽  
...  
Keyword(s):  
Fragile X Syndrome ◽  
Neuronal Development ◽  
Fragile X ◽  
In Vitro Models ◽  
Synaptic Activity ◽  
Human Neurons ◽  
Induced Pluripotent ◽  
And Function ◽  
The Brain

Abnormal neuronal development in Fragile X syndrome (FXS) is poorly understood. Data on FXS patients remain scarce and FXS animal models have failed to yield successful therapies. In vitro models do not fully recapitulate the morphology and function of human neurons. Here, we co-injected neural precursor cells (NPCs) from FXS patient-derived and corrected isogenic control induced pluripotent stem cells into the brain of neonatal immune-deprived mice. The transplanted cells populated the brain and a proportion differentiated into neurons and glial cells. Single-cell RNA sequencing of transplanted cells revealed upregulated excitatory synaptic transmission and neuronal differentiation pathways in FXS neurons. Immunofluorescence analyses showed accelerated maturation of FXS neurons after an initial delay. Additionally, increased percentages of Arc- and Egr1-positive FXS neurons and wider dendritic protrusions of mature FXS striatal medium spiny neurons pointed to an increase in synaptic activity and synaptic strength as compared to control. This transplantation approach provides new insights into the alterations of neuronal development in FXS by facilitating physiological development of cells in a 3D context, and could be used to test new therapeutic compounds correcting neuronal development defects in FXS.

scholarly journals Drosophila immune cells extravasate from vessels to wounds using Tre1 GPCR and Rho signaling

2018 ◽  
Vol 217 (9) ◽  
pp. 3045-3056 ◽  
Author(s):  
Leila Thuma ◽  
Deborah Carter ◽  
Helen Weavers ◽  
Paul Martin
Keyword(s):  
Immune Cells ◽  
Immune Cell ◽  
Innate Immune ◽  
Murine Models ◽  
Pupal Development ◽  
Epithelial Migration ◽  
Drosophila Model ◽  
Rate Limiting ◽  
Insight Into

Inflammation is pivotal to fight infection, clear debris, and orchestrate repair of injured tissues. Although Drosophila melanogaster have proven invaluable for studying extravascular recruitment of innate immune cells (hemocytes) to wounds, they have been somewhat neglected as viable models to investigate a key rate-limiting component of inflammation—that of immune cell extravasation across vessel walls—due to their open circulation. We have now identified a period during pupal development when wing hearts pulse hemolymph, including circulating hemocytes, through developing wing veins. Wounding near these vessels triggers local immune cell extravasation, enabling live imaging and correlative light-electron microscopy of these events in vivo. We show that RNAi knockdown of immune cell integrin blocks diapedesis, just as in vertebrates, and we uncover a novel role for Rho-like signaling through the GPCR Tre1, a gene previously implicated in the trans-epithelial migration of germ cells. We believe this new Drosophila model complements current murine models and provides new mechanistic insight into immune cell extravasation.

scholarly journals The RNA-binding fragile-X mental retardation protein and its role beyond the brain

2020 ◽  
Vol 12 (4) ◽  
pp. 903-916 ◽  
Author(s):  
Cassandra Malecki ◽  
Brett D. Hambly ◽  
Richmond W. Jeremy ◽  
Elizabeth N. Robertson
Keyword(s):  
Mental Retardation ◽  
Rna Binding ◽  
Fragile X ◽  
Fragile X Mental Retardation ◽  
Mental Retardation Protein ◽  
The Brain

scholarly journals IMMU-39. RNA LOADED LIPID-NANOPARTICLES FUNCTION AS CUSTOMIZABLE IMMUNOTHERAPEUTIC VEHICLES AGAINST MALIGNANT GLIOMAS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi127-vi127
Author(s):  
Adam Grippin ◽  
Brandon Wummer ◽  
Hector Mendez-Gomez ◽  
Brian Stover ◽  
Jianping Huang ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Tumor Microenvironment ◽  
Immune Cells ◽  
Lipid Nanoparticles ◽  
Lymphoid Organs ◽  
Innate Immune ◽  
T Cell Immunity ◽  
Innate Immune Cells ◽  
Cell Immunity ◽  
The Brain

Abstract BACKGROUND While dendritic cell (DC) vaccine therapy has shown considerable promise for glioblastoma (GBM) patients (Mitchell et al. Nature, 2015), their advancement into human clinical trials has been fraught with challenges in the development, manufacturing, and marketing of successful cancer immunotherapies. To circumvent the challenges associated with cell therapy, we have developed a new platform technology consisting of tumor derived mRNA complexed into lipid-nanoparticles (RNA-NPs) for systemic delivery to DCs in vivo and induction of antigen specific T cell immunity against GBM. OBJECTIVES/ METHODS We sought to assess if surface and charge modifications to our custom lipid-NP could facilitate its localization to lymphoid organs and the brain tumor microenvironment. RESULTS We demonstrate that intravenous administration of our unmodified custom RNA-NPs mediate systemic activation of DCs; these include activation of CD11c+ cells in the brains of animals with intact blood brain-barriers (BBBs). RNA-NPs mediate antigen specific T cell immunity and anti-tumor efficacy with increased tumor infiltrating lymphocytes against a NF-1/p53 mutant glioma that recapitulates features of human GBM in immunocompetent mice. Modification of surface charge could direct these RNA-NPs to lymphoid organs (e.g. spleen, lymph nodes) while modification of the lipid backbone (with cholesterol) enhances localization to innate immune cells in NF-1/p53 mutant and GL261 gliomas. We therefore assessed if this customizable lipid-NP could be leveraged for delivery of immune checkpoint inhibitors (ICIs) (i.e. PD-L1 siRNA) to the brain tumor microenvironment. Compared with scrambled siRNA-NPs in combination with ICIs, surface modified siRNA-NPs (antagonizing PD-L1) in combination with ICIs mediated significant antitumor efficacy with 37% long term survivors in an otherwise fatal brain tumor model. CONCLUSION We designed multifunctional RNA-NPs with a simple, scalable synthesis method that enables delivery of nucleic acids to innate immune cells in lymphoid organs and brain tumors.

Acamprosate rescues neuronal defects in the Drosophila model of Fragile X Syndrome

Life Sciences ◽  
2018 ◽  
Vol 195 ◽  
pp. 65-70 ◽  
Author(s):  
Russell L. Hutson ◽  
Rachel L. Thompson ◽  
Andrew P. Bantel ◽  
Charles R. Tessier
Keyword(s):  
Fragile X Syndrome ◽  
Fragile X ◽  
Drosophila Model
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