Chemogenetic activation of astrocytes modulates sleep-wakefulness states in a brain region-dependent manner.

Study Objectives: Astrocytes change their intracellular calcium (Ca) concentration during sleep/wakefulness states in mice. Furthermore, the Ca dynamics in astrocytes vary depending on the brain region. However, it remains unclear whether alterations in astrocyte activity can affect sleep-wake states and cortical oscillations in a brain region-dependent manner.

Region-Specific and State-Dependent Astrocyte Ca Dynamics during the Sleep-Wake Cycle in Mice.

Neural activity is diverse, and varies depending on brain regions and sleep/wakefulness states. However, whether astrocyte activity differs between sleep/wakefulness states, and whether there are differences in astrocyte activity among brain regions remain poorly understood. Therefore, in this study, we recorded astrocyte intracellular calcium (Ca) concentrations of mice during sleep/wakefulness states in the cortex, hippocampus, hypothalamus, cerebellum, and pons using fiber photometry.

Intracellular ATP levels in mouse cortical excitatory neurons varies with sleep-wake states.

Whilst the brain is assumed to exert homeostatic functions to keep the cellular energy status constant under physiological conditions, this has not been experimentally proven. Here, we conducted in vivo optical recordings of intracellular concentration of adenosine 5'-triphosphate (ATP), the major cellular energy metabolite, using a genetically encoded sensor in the mouse brain. We demonstrate that intracellular ATP levels in cortical excitatory neurons fluctuate in a cortex-wide manner depending on the sleep-wake states, correlating with arousal.

Segmented Iba1-Positive Processes of Microglia in Autism Model Marmosets.

Autism spectrum disorder (ASD) is one of the most widespread neurodevelopmental disorders, characterized by impairment in social interactions, and restricted stereotyped behaviors. Using immunohistochemistry and positron emission tomography (PET), several studies have provided evidence of the existence of activated microglia in ASD patients. Recently, we developed an animal model of ASD using the new world monkey common marmoset () and demonstrated ASD-like social impairment after the administration of valproic acid (VPA).

Identification of two novel Shank3 transcripts in the developing mouse neocortex.

SHANK3 is a synaptic scaffolding protein enriched in the post-synaptic density of excitatory synapses. Since several SHANK3 mutations have been identified in a particular phenotypic group of patients with autism spectrum disorder (ASD), SHANK3 is strongly suspected of being involved in the pathogenesis and neuropathology of ASD. Several SHANK3 isoforms are known to be produced in the developing brain, but they have not been fully investigated.

Involvement of activated microglia in increased vulnerability of motoneurons after facial nerve avulsion in presymptomatic amyotrophic lateral sclerosis model rats.

Activated microglia are observed in various neurodegenerative diseases and are thought to be involved in the processes of neuronal cell death. Motoneuron damage in the facial nuclei after facial nerve avulsion is accelerated in presymptomatic transgenic rats expressing human mutant Cu(2+) /Zn(2+) superoxide dismutase 1 (SOD1), compared with that in wild-type rats. To reveal the functional role of microglia in motoneuronal death, we investigated the microglial response after facial nerve avulsion in presymptomatic mutant SOD1(H46R) (mSOD1(H46R) ) rats.

Adenosine A3 receptor is involved in ADP-induced microglial process extension and migration.

The extension of microglial processes toward injured sites in the brain is triggered by the stimulation of the purinergic receptor P2Y(12) by extracellular ATP. We recently showed that P2Y(12) stimulation by ATP induces microglial process extension in collagen gels. In the present study, we found that a P2Y(12) agonist, 2-methylthio-ADP (2MeSADP), failed to induce the process extension of microglia in collagen gels and that co-stimulation with adenosine, a phosphohydrolytic derivative of ATP, and 2MeSADP restored the chemotactic process extension.

Appearance of phagocytic microglia adjacent to motoneurons in spinal cord tissue from a presymptomatic transgenic rat model of amyotrophic lateral sclerosis.

Microglial activation occurs early during the pathogenesis of amyotrophic lateral sclerosis (ALS). Recent evidence indicates that the expression of mutant Cu(2+)/Zn(2+) superoxide dismutase 1 (SOD1) in microglia contributes to the late disease progression of ALS. However, the mechanism by which microglia influence the neurodegenerative process and disease progression in ALS remains unclear.

Adenoviral gene delivery of pigment epithelium-derived factor protects striatal neurons from quinolinic acid-induced excitotoxicity.

The 50-kDa secreted glycoprotein pigment epithelium-derived factor (PEDF) is neuroprotective for various types of cultured neurons, but whether it is neuroprotective for neurons in vivo is not known. We examined the effects of adenovirus-mediated gene transfer of PEDF on quinolinic acid (QA)-induced neurotoxicity in rats. Adenoviral vector containing the human PEDF gene (Ad.

P2Y12 receptor-mediated integrin-beta1 activation regulates microglial process extension induced by ATP.

Microglia are the primary immune surveillance cells in the brain, and when activated they play critical roles in inflammatory reactions and tissue repair in the damaged brain. Microglia rapidly extend their processes toward the damaged areas in response to stimulation of the metabotropic ATP receptor P2Y(12) by ATP released from damaged tissue. This chemotactic response is a highly important step that enables microglia to function properly at normal and pathological sites in the brain.

Gene transfer of PEDF attenuates ischemic brain damage in the rat middle cerebral artery occlusion model.

Pigment epithelium-derived factor (PEDF) is a 50-kDa glycoprotein that protects various types of cultured neurons against neurotoxic stimuli, but its precise role in the CNS is not fully understood. In this study, we used rats whose brains were transfected to over-express human PEDF in order to elucidate the neuroprotective effect of PEDF following transient middle cerebral artery occlusion (MCAO). A replication-defective adenoviral vector containing the human PEDF gene (Ad.

Changes in pigment epithelium-derived factor expression following kainic acid induced cerebellar lesion in rat.

Pigment epithelium-derived factor (PEDF) is a potent and broad-acting neurotrophic factor that protects various types of cultured neurons against glutamate excitotoxicity and induced apoptosis. The expression pattern and functions of PEDF in the central nervous system (CNS) remain largely undetermined. In this study, we analyzed the spatial and temporal expression of PEDF in normal and kainic acid (KA)-induced lesioned rat cerebellum using immunoblotting, immunohistochemistry and fluorescent in situ hybridization techniques.

The regulation of pro-inflammatory gene expression induced by pigment epithelium-derived factor in rat cultured microglial cells.

Pigment epithelium-derived factor (PEDF) is a potent and broadly acting neurotrophic factor that protects various cultured neurons against apoptotic stimuli. To investigate whether PEDF acts not only on neurons, but also glial cells, we analyzed the effects of recombinant human PEDF (rhPEDF) on cytokine mRNA levels, transcription factors, and signal transduction pathways in cultured microglial cells. RT-PCR analysis revealed that pro-inflammatory genes such as IL-1beta, IL-6, and TNFalpha were induced in rhPEDF-treated cultured microglial cells.

Pigment epithelium-derived factor induces pro-inflammatory genes in neonatal astrocytes through activation of NF-kappa B and CREB.

Pigment epithelium-derived factor (PEDF) is a potent and broadly acting neurotrophic factor that protects neurons in various types of cultured neurons against glutamate excitotoxicity and induced-apoptosis. Some of the effects of PEDF reflect specific changes in gene expression, mediated via activation of the transcription factor NF-kappa B in neurons. To investigate whether PEDF also modulates gene expression in astrocytes, we employed the use of RT-PCR to analyze the gene expression of certain pro-inflammatory genes and found that genes such as IL-1 beta, IL-6, TNF-alpha, MIP1 alpha, and MIP3 alpha were induced in PEDF-treated cultured neonatal astrocytes, but not in adult astrocytes.