MicroRNAs (miRNAs) are endogenously expressed small, non-coding transcripts that regulate protein expression. Substantial evidences suggest that miRNAs are enriched in central nervous system, where they are hypothesized to play pivotal roles during neural development. In the present study, we analyzed miRNAs expression in mice cerebral cortex and hippocampus at different developmental stages and found miR-29a increased dramatically at postnatal stages. In addition, we provided strong evidences that miR-29a is enriched in mature neurons both in vitro and in vivo. Further investigation demonstrated that the activation of glutamate receptors induced endogenous miR-29a level in primary neurons. Moreover, we showed that miR-29a directly regulated its target protein Doublecortin (DCX) expression, which further modulated axon branching in primary culture. Together, our results suggested that miR-29a play an important role in neuronal development of mice cerebrum.
Animals ; Axons ; metabolism ; physiology ; Hippocampus ; growth & development ; metabolism ; Mice ; MicroRNAs ; genetics ; metabolism ; Microtubule-Associated Proteins ; genetics ; Neurogenesis ; Neurons ; metabolism ; Neuropeptides ; genetics ; Primary Cell Culture

The current epidemic of obesity and its associated metabolic syndromes impose unprecedented challenges to our society. Despite intensive research on obesity pathogenesis, an effective therapeutic strategy to treat and cure obesity is still lacking. Exciting studies in last decades have established the importance of the leptin neural pathway in the hypothalamus in the regulation of body weight homeostasis. Important hypothalamic neuropeptides have been identified as critical neurotransmitters from leptin-sensitive neurons to mediate leptin action. Recent research advance has significantly expanded the list of neurotransmitters involved in body weight-regulating neural pathways, including fast-acting neurotransmitters, gamma-aminobutyric acid (GABA) and glutamate. Given the limited knowledge on the leptin neural pathway for body weight homeostasis, understanding the function of neurotransmitters released from key neurons for energy balance regulation is essential for delineating leptin neural pathway and eventually for designing effective therapeutic drugs against the obesity epidemic.
Animals ; Energy Metabolism ; Gene Expression ; Humans ; Hunger ; Hypothalamus ; metabolism ; physiology ; Leptin ; metabolism ; physiology ; Neural Pathways ; metabolism ; Neuropeptides ; genetics ; metabolism ; Obesity ; metabolism

1-Alkyl-2-acetylglycerophosphocholine Esterase ; genetics ; Chromosome Aberrations ; Humans ; Infant ; Infant, Newborn ; Ion Channels ; physiology ; Melanocyte-Stimulating Hormones ; genetics ; Microtubule-Associated Proteins ; genetics ; Mutation ; Neurons ; physiology ; Neuropeptides ; genetics ; Spasms, Infantile ; etiology ; genetics ; Tumor Suppressor Proteins ; genetics

Rac1 belongs to the family of Rho GTPases, and plays important roles in the brain function. It affects the cell migration and axon guidance via regulating the cytoskeleton and cellular morphology. However, the effect of its dynamic activation in regulating physiological function remains unclear. Recently, a photoactivatable analogue of Rac1 (PA-Rac1) has been developed, allowing the activation of Rac1 by the specific wavelength of light in living cells. Thus, we constructed recombinant adeno-associated virus (AAV) of PA-Rac1 and its light-insensitive mutant PA-Rac1-C450A under the control of the mouse glial fibrillary acidic protein (mGFAP) promoter to manipulate Rac1 activity in astrocytes by optical stimulation. Primary culture of hippocampal astrocytes was infected with the recombinant AAV-PA-Rac1 or AAV-PA-Rac1-C450A. Real-time fluorescence imaging showed that the cell membrane of the astrocyte expressing PA-Rac1 protruded near the light spot, while the astrocyte expressing PA-Rac1-C450A did not. We injected AAV-PA-Rac1 and AAV-PA-Rac1-C450A into dorsal hippocampus to investigate the role of the activation of Rac1 in regulating the associative learning. With optical stimulation, the PA-Rac1 group, rather than the PA-Rac1-C450A group, showed slower learning curve during the fear conditioning compared with the control group, indicating that activating astrocytic Rac1 blocks the formation of contextual memory. Our data suggest that the activation of Rac1 in dorsal hippocampal astrocyte plays an important role in the associative learning.
Animals ; Astrocytes ; physiology ; Cell Membrane ; Cell Movement ; Conditioning, Classical ; Cytoskeleton ; Dependovirus ; Fear ; Hippocampus ; physiology ; Memory ; Mice ; Mice, Inbred C57BL ; Neuropeptides ; genetics ; physiology ; Optogenetics ; rac1 GTP-Binding Protein ; genetics ; physiology

BACKGROUNDSleep/wake disturbances in patients with amyotrophic lateral sclerosis (ALS) are well-documented, however, no animal or mechanistic studies on these disturbances exist. Orexin is a crucial neurotransmitter in promoting wakefulness in sleep/wake regulation, and may play an important role in sleep disturbances in ALS. In this study, we used SOD1-G93A transgenic mice as an ALS mouse model to investigate the sleep/wake disturbances and their possible mechanisms in ALS.

METHODSElectroencephalogram/electromyogram recordings were performed in SOD1-G93A transgenic mice and their littermate control mice at the ages of 90 and 120 days, and the samples obtained from these groups were subjected to quantitative reverse transcriptase-polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay.

RESULTSFor the first time in SOD1-G93A transgenic mice, we observed significantly increased wakefulness, reduced sleep time, and up-regulated orexins (prepro-orexin, orexin A and B) at both 90 and 120 days. Correlation analysis confirmed moderate to high correlations between sleep/wake time (total sleep time, wakefulness time, rapid eye movement [REM] sleep time, non-REM sleep time, and deep sleep time) and increase in orexins (prepro-orexin, orexin A and B).

CONCLUSIONSleep/wake disturbances occur before disease onset in this ALS mouse model. Increased orexins may promote wakefulness and result in these disturbances before and after disease onset, thus making them potential therapeutic targets for amelioration of sleep disturbances in ALS. Further studies are required to elucidate the underlying mechanisms in the future.

Amyotrophic Lateral Sclerosis ; genetics ; metabolism ; Animals ; Female ; Intracellular Signaling Peptides and Proteins ; genetics ; metabolism ; Male ; Mice ; Mice, Transgenic ; Neuropeptides ; genetics ; metabolism ; Orexins ; Reverse Transcriptase Polymerase Chain Reaction ; Sleep ; physiology ; Superoxide Dismutase ; genetics ; metabolism ; Superoxide Dismutase-1 ; Wakefulness ; physiology

OBJECTIVETo explore the effect of soy isoflavone on obesity in the light of hypothalamus and peripheral orexigenic gene regulation.

METHODSFifty-four female rats were randomly assigned to 6 groups: one sham-operated group (SHAM), one ovariectomized (OVX) control group, three OVX groups fed with 400 ppm (L-SI), 1200 ppm (M-SI) and 3600 ppm (H-SI) isoflavone respectively, and one OVX group receiving 0.45 ppm diethylstilbestrol (EC). All rats were allowed to take high-fat diet for 4 weeks. Some neuropeptides were measured by RT-PCR. These neuropeptides included NPY, pro-opiomelanocortin (POMC), cocaine and amphetamine regulated transcript (CART), orexin, melanin-concentrating hormone (MCH), melanin-concentrating hormone precursor (P-MCH), ghrelin, and leptin.

RESULTSCompared with the OVX control group, the body weight and food intake in the H-SI group were reduced significantly and there was a significant dose-dependent manner in the 3 isoflavone groups. The results of RT-PCR showed that the NPY level in the 3 isoflavone groups was significantly increased and the POMC/CART gene expression decreased significantly in rats' hypothalamus compared with that in the OVX control group. However, the expression of orexin, MCH and P-MCH had no change. The peripheral grelin mRNA expression was higher in the 3 isoflavone groups, while leptin gene expression in the fat was not consistent.

CONCLUSIONSThis research showed that isoflavone could prevent obesity induced by high-fat diet and ovariectomy through regulating hypothalamus and peripheral orexigenic gene expressions associated with food intake.

Animals ; Dietary Fats ; pharmacology ; Feeding Behavior ; drug effects ; physiology ; Female ; Gene Expression Regulation ; drug effects ; Hypothalamus ; Isoflavones ; chemistry ; pharmacology ; Neuropeptides ; genetics ; metabolism ; Obesity ; Ovariectomy ; RNA, Messenger ; genetics ; metabolism ; Rats ; Soybeans ; chemistry

Homer protein was identified based on its rapid induction in rat hippocampal granule cell neurons following excitatory synaptic activity. Although the presence of the Homer gene in the peripheral tissues has been observed in previous reports, the physiological function of the Homer protein in these tissues has not been noted. In this experiment, a Homer-2a cDNA fragment was successfully amplified by RTPCR in the involuting phase of human hemangioma but not in the human vascular malformation and normal vessel. After isolation of full Homer cDNA in a mouse liver cDNA library, E1-deleted recombinant adenovirus expressing the Homer protein (Adv.CMV.mHomer-2a) was constructed to determine its physiological function in peripheral tissues. Adv.CMV.mHomer2a, but not Adv.CMV.LacZ (recombinant adenovirus expressing beta-galactosidase), strongly inhibited the growth rate of HUVECs (human umbilical vein endothelial cells) probably via inducing apoptosis determined by acridine orange/ethidium bromide (AO/EB) staining methods. This study suggests that the Homer gene is present in human specimens in the involuting phase of hemangioma, and it might be involved in the growth control.
Adolescent ; Adult ; Animals ; Apoptosis ; Base Sequence ; Blood Vessels/*abnormalities ; Carrier Proteins/genetics/*physiology ; Cells, Cultured ; Child ; Child, Preschool ; DNA, Complementary/genetics ; Endothelium, Vascular/cytology ; Female ; Hemangioma/blood supply/*genetics ; Humans ; Male ; Mice ; Middle Aged ; Neuropeptides/genetics/*physiology ; Rats ; Reverse Transcriptase Polymerase Chain Reaction ; Skin/blood supply ; Skin Neoplasms/blood supply/*genetics