Cortical synaptic loss has emerged as an early abnormality in Alzheimer's disease (AD) with a strong relationship to cognitive performance. However, the status of synapses in frontotemporal lobar degeneration (FTLD) has received meager experimental attention. The purpose of this study was to investigate changes in cortical synaptic proteins in FTLD with tar DNA binding protein-43 (TDP-43) proteinopathy. A second aim was to study phagocytosis of synaptic proteins by microglia as a surrogate for synaptic pruning. Western blot analysis in frozen tissue from the middle frontal gyrus revealed decreased levels of the presynaptic protein synaptophysin, but slightly increased levels of the postsynaptic density protein 95 (PSD95) in FTLD-TDP. Levels of the dendritic spine protein spinophilin displayed the largest decrease. Double immunofluorescent staining visualized aggregate or punctate synaptic protein immunoreactivity in microglia. Overall, the proportion of microglia containing synaptic proteins was larger in FTLD-TDP when compared with normal controls. The increase in PSD95 levels may represent reactive upregulation of this protein, as suggested in AD. While greater numbers of microglia containing synaptic proteins is consistent with loss of synapses in FTLD-TDP, it may also be an indication of abnormal synaptic pruning by microglia.
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http://dx.doi.org/10.1016/j.neuint.2024.105719 | DOI Listing |
Sci Adv
January 2025
Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
The pathophysiology of neurodevelopmental disorders involves vulnerable neural populations, including striatal circuitry, and convergent molecular nodes, including chromatin regulation and synapse function. Despite this, how epigenetic regulation regulates striatal development is understudied. Recurrent de novo mutations in are associated with intellectual disability and autism.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Neurology, the Second Affiliated Hospital, Neuroscience Research Center, Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an 710000, China.
Neurotransmitters and neuromodulators can be released via either action potential (AP)-evoked transient or AP-independent continuous neurotransmission. The elevated AP-evoked neurotransmission in the primary sensory neurons plays crucial roles in hyperalgesia. However, whether and how the AP-independent continuous neurotransmission contributes to hyperalgesia remains largely unknown.
View Article and Find Full Text PDFJ Gerontol A Biol Sci Med Sci
January 2025
Centro de Investigación Clínica Avanzada (CICA), Hospital Clínico Universidad de Chile.
Postoperative delirium (POD), an acute cognitive dysfunction linked to morbidity and mortality, is characterized by memory impairments and disturbances in consciousness, particularly in patients aged 65 and older. Neuroinflammation and NAD+ imbalance are key mechanisms behind POD, leading to synaptic and cognitive deterioration. However, how surgery contributes to POD and neuroinflammation remains unclear, and effective treatments are lacking.
View Article and Find Full Text PDFSubcell Biochem
January 2025
Faculty of Medicine and Faculty of Life Sciences, Institute of Biomedical Sciences (ICB), Universidad Andres Bello, Santiago, Chile.
In animals, memory formation and recall are essential for their survival and for adaptations to a complex and often dynamically changing environment. During memory formation, experiences prompt the activation of a selected and sparse population of cells (engram cells) that undergo persistent physical and/or chemical changes allowing long-term memory formation, which can last for decades. Over the past few decades, important progress has been made on elucidating signaling mechanisms by which synaptic transmission leads to the induction of activity-dependent gene regulation programs during the different phases of learning (acquisition, consolidation, and recall).
View Article and Find Full Text PDFJ Neurol
January 2025
Centre de Génétique Humaine, Centre Hospitalier Universitaire de Besançon, Besançon, France.
Introduction: The MAPT gene encodes Tau, a protein mainly expressed by neurons. Tau protein plays an important role in cerebral microtubule polymerization and stabilization, in axonal transport and synaptic plasticity. Heterozygous pathogenic variation in MAPT are involved in a spectrum of autosomal dominant neurodegenerative diseases known as taupathies, including Alzheimer's disease, Pick's disease, fronto-temporal dementia, cortico-basal degeneration and progressive supranuclear palsy.
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