The Journal of neuroscience : the official journal of the Society for Neuroscience
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Loss-of-function mutations in progranulin, a lysosomal glycoprotein, cause neurodegenerative disease. Progranulin haploinsufficiency causes frontotemporal dementia (FTD) and complete progranulin deficiency causes CLN11 neuronal ceroid lipofuscinosis (NCL). Progranulin replacement is a rational therapeutic strategy for these disorders, but there are critical unresolved mechanistic questions about a progranulin gene therapy approach, including its potential to reverse existing pathology. ⋯ Its beneficial effects were sortilin independent. AAV-derived progranulin was delivered to lysosomes and corrected lysosomal abnormalities. These data provide in vivo support for the efficacy of progranulin-boosting therapies for FTD and NCL.
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Environmental events are processed on multiple timescales via hierarchical organization of temporal receptive windows (TRWs) in the brain. The dependence of neural timescales and TRWs on altered states of consciousness is unclear. States of reduced consciousness are marked by a shift toward slowing of neural dynamics (<1 Hz) in EEG/ECoG signals. ⋯ Here, we demonstrate for the first time that sedation with propofol is accompanied by the prolongation of the timescales of intrinsic BOLD signals presumably reflecting enlarged TRWs. We show that this is accomplished by an increase of local and regional signal synchronization, effects that may disrupt information exchange among distant brain regions. Furthermore, we show that the timescales of intrinsic BOLD signals exhibit distinct dynamic signatures in sedation, deep anesthesia, and disorders of consciousness.
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Systemic fentanyl induces hyperalgesic priming, long-lasting neuroplasticity in nociceptor function characterized by prolongation of inflammatory mediator hyperalgesia. To evaluate priming at both nociceptor terminals, we studied, in male Sprague Dawley rats, the effect of local administration of agents that reverse type I (protein translation) or type II [combination of Src and mitogen-activated protein kinase (MAPK)] priming. At the central terminal, priming induced by systemic, intradermal, or intrathecal fentanyl was reversed by the combination of Src and MAPK inhibitors, but at the peripheral terminal, it was reversed by the protein translation inhibitor. ⋯ SIGNIFICANCE STATEMENT Fentanyl, acting at the μ-opioid receptor (MOR), induces hyperalgesia and hyperalgesic priming at both the central and peripheral terminal of nociceptors and this is mediated by endoplasmic reticulum Ca2+ signaling. Priming in the central terminal is type II, whereas that in the peripheral terminal is type I. Our findings may provide useful information for the design of drugs with improved therapeutic profiles, selectively disrupting individual MOR signaling pathways, to maintain an adequate long-lasting control of pain.
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Adult hippocampal neurogenesis has been shown to be required for certain types of cognitive function. For example, studies have shown that these neurons are critical for pattern separation, the ability to store similar experiences as distinct memories. Although traumatic brain injury (TBI) has been shown to cause the loss of newborn hippocampal neurons, the signaling pathway(s) that triggers their death is unknown. ⋯ However, the mechanism(s) that causes the loss of these cells after TBI is poorly understood. We show that endoplasmic reticulum (ER) stress pathways are activated in newborn neurons after TBI, and that manipulation of the CHOP cascade improves newborn neuron survival and cognitive outcome. These results suggest that treatments that prevent/resolve ER stress may be beneficial in treating TBI-triggered memory dysfunction.
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In the CNS, myelination and remyelination depend on the successful progression and maturation of oligodendroglial lineage cells, including proliferation and differentiation of oligodendroglial progenitor cells (OPCs). Previous studies have reported that Sox2 transiently regulates oligodendrocyte (OL) differentiation in the embryonic and perinatal spinal cord and appears dispensable for myelination in the postnatal spinal cord. However, the role of Sox2 in OL development in the brain has yet to be defined. ⋯ SIGNIFICANCE STATEMENT Promoting myelin formation and repair has translational significance in treating myelin-related neurological disorders, such as periventricular leukomalacia and multiple sclerosis in which brain developmental myelin formation and myelin repair are severely affected, respectively. In this report, analyses of a series of genetic conditional knock-out systems targeting different oligodendrocyte stages reveal a previously unappreciated role of Sox2 in coordinating upstream proliferation and downstream differentiation of oligodendroglial lineage cells in the mouse brain during developmental myelination and CNS remyelination. Our study points to the potential of manipulating Sox2 and its downstream pathways to promote oligodendrocyte regeneration and CNS myelin repair.