Project description:Adult neurogenesis, found in two neurogenic regions of the brain, has profound roles in neural plasticity and brain function. A hallmark feature of neurodegeneration is neuroinflammation, which can either enhance or inhibit neurogenesis depending on the context of the brain microenvironment. The consequences of deficient DNA repair in adult neurogenesis and neuroinflammation are poorly understood despite their potential relevance for homeostasis. We previously reported that loss of NEIL1, an important DNA glycosylase involved in DNA base excision repair, is associated with deficiencies in spatial memory, olfaction, and protection against ischemic stroke in mice. Here, we show that Neil1-/- mice display an anxiety-mediated behavior in the open field test, a deficient recognitive memory in novel object recognition and increased neuroinflammatory response under basal conditions. Further, mice lacking NEIL1 have decreased neurogenesis and deficient resolution of neuroinflammation following gamma irradiation (IR)-induced stress compared to WT mice. Neil1-/- IR-exposed mice also exhibit increased DNA damage and apoptosis in the hippocampus. Interestingly, behavioral tests two weeks after IR showed impaired stress response in the Neil1-/- mice. Our data indicate that NEIL1 plays an important role in adult neurogenesis and in the resolution of neuroinflammation.
Project description:Neuroinflammation plays a role in the progression of several neurodegenerative disorders. We used a lipolysaccharide (LPS) model of neuroinflammation to characterize the gene expression changes underlying the inflammatory and behavioral effects of neuroinflammation. A single intracerebroventricular injection of LPS (5 ug) was administered into the lateral ventricle of mice and, 24 hours later, we examined gene expression in the cerebral cortex and hippocampus using microarray technology. Gene Ontology (GO) terms for inflammation and the ribosome were significantly enriched by LPS, whereas GO terms associated with learning and memory had decreased expression. We detected 224 changed transcripts in the cerebral cortex and 170 in the hippocampus. Expression of Egr1 (also known as Zif268) and Arc, two genes associated with learning and memory, was significantly lower in the cortex, but not hippocampus, of LPS-treated animals. Overall, altered expression of these genes may underlie some of the inflammatory and behavioral effects of neuroinflammation. Mice were given intracerebroventricular injections of saline vehicle (n = 4) or lipopolysaccharide (n = 4). Twenty-four hours later, we dissected the hippocampus and cerebral cortex and processed the tissue for microarray analysis. Gene expression changes observed in the microaray data were validated with quantitative real-time PCR.
Project description:Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.
Project description:A social-stress mouse model, involving exposure of an intruder (male C57BL/6) mouse to a resident aggressor (male SJL) mouse followed by exposure to trauma reminders with post-trauma periods, was used to simulate features of human PTSD. Transcriptome changes in blood, brain regions and spleen, and DNA methylome changes in hemi-brain of aggressor-exposed and control C57BL/6 mice were assayed at one, 10 and 42 days of post-trauma periods. Assessments of activation patterns for differentially expressed transcripts (overlapping among hemi-brain, blood and spleen), and differentially methylated promoter regions showed increased activations of inflammatory pathways, and inhibited pathways related to neurogenesis and synaptic plasticity at longer post-trauma days. In amygdala, hippocampus and medial pre-frontal cortext, these pathways were activated at earlier post-trauma periods. But at longer post-trauma periods, neurogenesis and synaptic plasticity were inhibited while lower level of activated inflammation persisted in hippocampus and medial pre-frontal cortex. Pathways implicated in diabetes, insulin signaling, metabolic disorder, mitochondrial dysfunctions, circadian disruption, oxidative stress and inhibited telomere maintenance were significantly enriched. Identification of brain – blood overlapping molecular signatures provide increased confidence in using blood as brain surrogate sample for clinical translation. Our findings suggest that stress-induced inflammation triggers impaired neurogenesis, cognitive decline, and chronic pain (physical complaints in PTSD patients). Signaling pathways implicated in neurogenesis and synaptic plasticity seem to be mediating the effect of neuroinflammation in the development and maintenance of behavioral manifestations of PTSD. While inflammation seems to be directly involved in tissue damage triggering, exacerbating or maintaining the somatic comorbid pathologies of PTSD.
Project description:By precisely dissected LC-MS/MS for proteomics and phosphoproteomics, we found that deletion of NRBF2 disrupts neurogenesis-related protein network in the DG, such as neurogenesis, cell development, cell morphogenesis, cellular homeostasis, and synaptic plasticity.
Project description:We propose that neuroinflammation and skeletal muscle interaction in intermittent restraint stress regulate skeletal muscle mass through a defined mechanism.