Interleukin 1 receptor contributes to methamphetamine- and sleep deprivation-induced hypersomnolence
ABSTRACT Methamphetamine-induced wakefulness is dependent on monoamine transporter blockade. Subsequent to methamphetamine-induced wakefulness, the amount of time spent asleep and the depth of sleep are increased relative to baseline sleep. The mechanisms that drive methamphetamine-induced hypersomnolence are not fully understood. We recently observed that methamphetamine exposure elevates the expression of the sleep-promoting cytokine, interleukin-1β in CD11b-positive monocytes within the brain. Here, we sought to determine whether activation of the interleukin 1 receptor (IL1R) drives the increase in the depth and amount of sleep that occurs subsequent to methamphetamine-induced wakefulness. IL1R-deficient mice and wild type control mice were subjected to systemic methamphetamine (1 and 2mg/kg) and saline treatments. The wake-promoting effect of methamphetamine was modestly potentiated by IL1R-deficiency. Additionally, the increase in time spent in NREMS subsequent to methamphetamine-induced wakefulness in wild type mice was abolished in IL1R-deficient mice. The increase in time spent asleep after 3h of behaviorally enforced wakefulness was also abolished in IL1R-deficient mice. Increases in EEG slow wave activity triggered by methamphetamine and sleep deprivation were of equal magnitude in IL1R-deficient and wild type mice. These data demonstrate that IL1R activation contributes to hypersomnolence that occurs after sleep loss, whether that sleep loss is triggered pharmacologically by methamphetamine or through behavioral sleep deprivation.
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ABSTRACT: Hepatic encephalopathy (HE) is a frequent complication of liver cirrhosis and is seen as the clinical manifestation of a low grade cerebral edema associated with oxidative-nitrosative stress. However, comprehensive data on HE-associated molecular derangements in human brain are lacking. In the present study we used a whole human genome micro-array approach for gene expression profiling in post mortem brain samples from cirrhotic patients with or without HE and non-cirrhotic controls. Altered expression levels were found for a total of 1012 genes in liver cirrhotic patients without and with HE and HE-characteristic gene expression changes were identified. Genes with altered expression pattern in HE were related to oxidative stress, microglia activation, receptor signalling, inflammatory pathways, cell proliferation and apoptosis. Despite an up-regulation of genes associated with microglia activation, pro-inflammatory cytokine mRNA profiles remained unchanged in the brain of patients with liver cirrhosis and HE as compared to controls. Interestingly, many genes counteracting pro-inflammatory signalling and inflammatory cytokine expression were up-regulated in the cerebral cortex of patients with liver cirrhosis and HE. It is concluded that pathogenetic mechanisms of HE deduced from cell culture and animal experiments, such as oxidative stress, altered Zn(2+) -homeostasis and microglia activation also apply to human brain from patients with liver cirrhosis and HE. The study also revealed a not yet recognized increased expression of genes antagonizing pro-inflammatory signalling and inflammatory cytokine expression. (HEPATOLOGY 2013.).Hepatology 06/2013; 57(6). DOI:10.1002/hep.26265 · 11.19 Impact Factor
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ABSTRACT: Experimental advances in the study of neuroglia signaling have been greatly accelerated by the generation of transgenic mouse models. In particular, an elegant manipulation that interferes with astrocyte vesicular release of gliotransmitters via overexpression of a dominant-negative domain of vesicular SNARE (dnSNARE) has led to documented astrocytic involvement in processes that were traditionally considered strictly neuronal, including the sleep-wake cycle, LTP, cognition, cortical slow waves, depression, and pain. A key premise leading to these conclusions was that expression of the dnSNARE was specific to astrocytes. Inconsistent with this premise, we report here widespread expression of the dnSNARE transgene in cortical neurons. We further demonstrate that the activity of cortical neurons is reversibly suppressed in dnSNARE mice. These findings highlight the need for independent validation of astrocytic functions identified in dnSNARE mice and thus question critical evidence that astrocytes contribute to neurotransmission through SNARE-dependent vesicular release of gliotransmitters. Copyright © 2014 the authors 0270-6474/14/3416594-11$15.00/0.The Journal of Neuroscience : The Official Journal of the Society for Neuroscience 12/2014; 34(50):16594-16604. DOI:10.1523/JNeurosci.2585-14.2014 · 6.75 Impact Factor
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ABSTRACT: Interactions between sleep and immune function are bidirectional. Although the mechanisms that govern these interactions are not fully elucidated, the pro-inflammatory cytokine, interleukin-1β (IL-1), is a known regulator of sleep and mediator of immune responses. To further clarify the underlying substrates of sleep and immune interactions, we engineered two transgenic mouse lines that express interleukin-1 receptor 1 (IL1R1) only in the central nervous system (CNS) and selectively on neurons (NSE-IL1R1) or astrocytes (GFAP-IL1R1). During spontaneous sleep, compared to wild type (WT) animals, NSE-IL1R1 and GFAP-IL1R1 mice have more rapid eye movement sleep (REMS) that is characterized by reduced theta power in the electroencephalogram (EEG) spectra. The non-REM sleep (NREMS) EEG of each of the IL1R1 transgenic mouse strains also is characterized by enhanced power in the delta frequency band. In response to 6 h of sleep deprivation, sleep of both IL1R1 transgenic mouse strains is more consolidated than that of WT animals. Additionally, the NREMS EEG of NSE-IL1R1 mice contains less delta power after sleep deprivation, suggesting astroglial IL1R1 activity may modulate sleep homeostasis. Intracerebroventricular injection of IL-1 fails to alter sleep or brain temperature of NSE-IL1R1 or GFAP-IL1R1 mice. These data suggest that selective IL1R1 expression on neurons or on astrocytes is not sufficient for centrally-administered IL-1 to induce sleep or fever. Lack of sleep and febrile responses to IL-1 in these IL1R1 transgenic mouse strains may be due to their inability to produce IL-6 in brain. Overall, these studies demonstrate, through the use of novel transgenic mice, that IL1R1 on neurons and astrocytes differentially mediates aspects of sleep under physiological conditions and in response to central IL-1 administration. Copyright © 2015 Elsevier Inc. All rights reserved.Brain Behavior and Immunity 04/2015; DOI:10.1016/j.bbi.2015.03.014 · 6.13 Impact Factor