Synapse loss is well regarded as the underlying cause for the progressive decline of memory function over the course of Alzheimer's disease (AD) development. Recent observations suggest that the accumulation of the Wnt antagonist Dickkopf-1 (Dkk1) in the AD brain plays a critical role in triggering synaptic degeneration. Mechanistically, Dkk1 cooperates with Kremen1 (Krm1), its transmembrane receptor, to block the Wnt/β-catenin signaling pathway. Here, we show that silencing Krm1 with miR-431 prevents amyloid-β-mediated synapse loss in cortico-hippocampal cultures isolated from triple transgenic 3xTg-AD mice. Exposure to AβDDL (an amyloid-β derived diffusive ligand) or Dkk1 reduced the number of pre- and post-synaptic puncta in primary neuronal cultures, while treatment with miR-431 prevented synapse loss. In addition, treatment with miR-431 also prevented neurite degeneration. Our findings demonstrate that miR-431 protects synapses and neurites from Aβ-toxicity in an AD cell culture model and may be a promising therapeutic target.
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http://dx.doi.org/10.3389/fncel.2018.00087 | DOI Listing |
Cell Rep
January 2025
Department of Neurological Surgery, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA; The Brain Tumor Center, Siteman Cancer Center, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address:
Mutation or deletion of the deubiquitinase USP7 causes Hao-Fountain syndrome (HAFOUS), which is characterized by speech delay, intellectual disability, and aggressive behavior and highlights important unknown roles of USP7 in the nervous system. Here, we conditionally delete USP7 in glutamatergic neurons in the mouse forebrain, triggering disease-relevant phenotypes, including sensorimotor deficits, impaired cognition, and aggressive behavior. Although USP7 deletion induces p53-dependent neuronal apoptosis, most behavioral abnormalities in USP7 conditional knockout mice persist following p53 loss.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
January 2025
Department of Neurology, Jinshan Hospital, Fudan University, 201508 Shanghai, China.
Background: Neuronal cholesterol deficiency may contribute to the synaptopathy observed in Alzheimer's disease (AD). However, the underlying mechanisms remain poorly understood. Intact synaptic vesicle (SV) mobility is crucial for normal synaptic function, whereas disrupted SV mobility can trigger the synaptopathy associated with AD.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Inha University, Incheon 22332, Republic of Korea.
Gravitational changes have been shown to cause significant abnormalities in various body systems, including the cardiovascular, immune, vestibular, and musculoskeletal systems. While numerous studies have examined the response of the vestibular system to gravitational stimulation, research on functional changes in the peripheral inner ear remains limited. The inner ear comprises two closely related structures: the vestibule and cochlea.
View Article and Find Full Text PDFNeurobiol Dis
January 2025
Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada. Electronic address:
The consequences of non-pathogenic huntingtin (HTT) reduction in the mature brain are of substantial importance as clinical trials for numerous HTT-lowering therapies are underway; many of which are non-selective in that they reduce both mutant and wild type protein variants. In this study, we injected CaMKII-promoted AAV-Cre directly into the hippocampus of adult HTT floxed mice to explore the role of wild-type huntingtin (wtHTT) in adult hippocampal pyramidal neurons and the broader implications of its loss. Our findings reveal that wtHTT depletion results in profound macroscopic morphological abnormalities in hippocampal structure, accompanied by significant reactive gliosis.
View Article and Find Full Text PDFG3 (Bethesda)
January 2025
Department of Neurobiology, School of Biological Sciences, University of California San Diego, La Jolla, CA 92093.
The conserved MAP3K DLKs are widely known for their functions in synapse formation, axonal regeneration and degeneration, and neuronal survival, notably under traumatic injury and chronic disease conditions. In contrast, their roles in other neuronal compartments are much less explored. Through an unbiased forward genetic screening in C.
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