Highlights d Adult-born neuron (ABN) activity during sleep can be seen using Ca 2+ imaging d ABNs active after learning reactivate in subsequent rapid eye movement (REM) sleep d Optogenetic manipulation of ABN activity in REM sleep impairs memory consolidation d This effect may be mediated by ABN synaptic plasticity
Neural stem and progenitor cells continue to generate new neurons in particular regions of the brain during adulthood. One of these neurogenic regions is the dentate gyrus (DG) of the hippocampus, which plays an important role in cognition and emotion. By exploiting this innate neuronal regeneration mechanism in the DG, new technologies have the potential to promote resistance to or recovery from brain dysfunction or degeneration. However, a deeper understanding of how adult DG neurogenesis is regulated by factors such as sleep and epigenetic modifications of gene expression could lead to further breakthroughs in the clinical application of neural stem and progenitor cells. In this review, we discuss the functions of adult-born DG neurons, describe the epigenetic regulation of adult DG neurogenesis, identify overlaps in how sleep and epigenetic modifications impact adult DG neurogenesis and memory consolidation, and suggest ways of using sleep or epigenetic interventions as therapies for neurodegenerative and psychiatric disorders. By knitting together separate strands of the literature, we hope to trigger new insights into how the functions of adult-generated neurons are directed by interactions between sleep-related neural processes and epigenetic mechanisms to facilitate novel approaches to preventing and treating brain disorders such as depression, post-traumatic stress disorder, and Alzheimer's disease. STEM CELLS 2018; 00:000-000
SIGNIFICANCE STATEMENTNew technologies utilizing neural stem cells in the adult hippocampus could potentially be used to promote innate resistance to or recovery from brain dysfunction or degeneration. Accumulating evidence indicates that adult hippocampal neurogenesis contributes to cognitive and emotional processing and is regulated by sleep and epigenetic modification of gene expression. Therefore, a richer understanding of how the interplay between sleep and epigenetics impacts adult hippocampal neurogenesis and thereby influences hippocampal function can help advance efforts to employ behavioral sleep interventions, epigenetic drugs, and novel neural stem cell-based therapeutic strategies for preventing or treating neurodegenerative and psychiatric disorders.
The objective of this study was to evaluate the free radical scavenging potential and high performance thin layer chromatography (HPTLC) fingerprinting of Indigofera tinctoria (I. tinctoria). Phytochemical analysis was carried out using standard methods, and free radical scavenging activity of the plant was determined using 2,2-diphenyl-1-picrylhydrazy (DPPH), nitric oxide (NO) and superoxide anion (normalO2−) radical scavenging capacities. HPTLC plate was kept in CAMAG TLC Scanner 3 and the Rf values at fingerprint data were recorded by WINCATS software. Aqueous extract of I. tinctoria reliably showed the total phenolics (267.2±2.42 mg/g), flavonoids (75.43±3.36 mg/g) and antioxidants (349.11±8.04 mg/g). The extract was found to have DPPH (52.08%), NO (23.12%) and normalO2− (26.79%) scavenging activities at the concentration of 250 μg/mL and the results were statistically significant compared with ascorbic acid standard (p<0.05). HPTLC results confirmed that the extract contained several potential active components such as phenols, flavonoids, saponins and terpenoids as the slides revealed multi-colored bands of varying intensities. This study confirmed that the plant had multipotential antioxidant and free radicals scavenging activities.
In anticipation of the massive burden of neurodegenerative disease within super-aged societies, great efforts have been made to utilize neural stem and progenitor cells for regenerative medicine. The capacity of intrinsic neural stem and progenitor cells to regenerate damaged brain tissue remains unclear, due in part to the lack of knowledge about how these newly born neurons integrate into functional circuitry. As sizable integration of adult-born neurons naturally occurs in the dentate gyrus region of the hippocampus, clarifying the mechanisms of this process could provide insights for applying neural stem and progenitor cells in clinical settings. There is convincing evidence of functional correlations between adult-born neurons and memory consolidation and sleep; therefore, we describe some new advances that were left untouched in our recent review.
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