scholarly journals Sleep regulates the glial engulfment receptor Draper to promote Wallerian degeneration

2019 ◽  
Author(s):  
Bethany A. Stahl ◽  
James B. Jaggard ◽  
Alex C. Keene
Keyword(s):  
Sleep Deprivation ◽  
Brain Function ◽  
Wallerian Degeneration ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Fruit Fly ◽  
Glial Activation ◽  
List Type ◽  
Toxic Substances ◽  
Activation Markers

SummarySleep, a universal behavior, is critical for diverse aspects of brain function. Chronic sleep disturbance is associated with numerous health consequences, including neurodegenerative disease and cognitive decline. Neurite damage due to apoptosis, trauma, or genetic factors is a common feature of aging, and clearance of damaged neurons is essential for maintenance of brain function. In the central nervous system, damaged neurites are cleared by Wallerian degeneration, in which activated microglia and macrophages engulf damaged neurons. The fruit fly Drosophila melanogaster provides a powerful model for investigating the relationship between sleep and Wallerian degeneration. Several lines of evidence suggest that glia influence sleep duration, sleep-mediated neuronal homeostasis, and clearance of toxic substances during sleep, raising the possibility that glial engulfment of damaged axons is regulated by sleep. To explore this possibility, we axotomized olfactory receptor neurons and measured the effects of sleep loss or gain on the clearance of damaged neurites. Mechanical sleep deprivation impaired the clearance of damaged neurites, whereas the sleep-promoting drug gaboxadol accelerated clearance. In sleep-deprived animals, multiple markers of glial activation were delayed, including activation of the JAK/STAT pathway, upregulation of the cell corpse engulfment receptor Draper, and innervation of the antennal lobe by glial membranes. These markers were all enhanced when sleep was induced in gaboxadol-treated flies. Taken together, these findings reveal a critical role for sleep in regulation glial activation and engulfment following axotomy, providing a platform for further investigations of the molecular mechanisms underlying sleep-dependent modulation of glial function and neurite clearance.HighlightsSleep deprivation impairs Wallerian degeneration in fruit flies.Pharmacological induction of sleep accelerates Wallerian degeneration.Sleep promotes innervation surrounding damaged neurites by phagocytic glia.Sleep increases levels of the glial activation markers Draper and Stat92E.

scholarly journals AANAT1 functions in astrocytes to regulate sleep homeostasis

2019 ◽  
Author(s):  
Sejal Davla ◽  
Gregory Artiushin ◽  
Daryan Chitsaz ◽  
Sally Li ◽  
Amita Sehgal ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Critical Role ◽  
Cholinergic Neurons ◽  
Adult Brain ◽  
List Type ◽  
Sleep Regulation ◽  
Control Functions ◽  
The Brain

SummaryCharacteristic features of sleep are conserved among species [1], and from humans to insects sleep is influenced by neural circuits involving monoamines such as serotonin and dopamine [2]. Glial cells have been increasingly implicated in mechanisms of baseline and homeostatic sleep regulation in mammals and flies [3–11], but it remains unknown whether and how glia might influence monoaminergic control of sleep. Sleep is regulated by circadian rhythms and a homeostatic drive to compensate for prolonged wakefulness, and growing evidence suggests that neural mechanisms controlling homeostatic sleep can be discriminated from those controlling baseline sleep [12–15]. In Drosophila, mutants of arylalkylamine N-acetyltransferase 1 (AANAT1lo) have normal baseline amounts of sleep and motor activity, but increased rebound sleep following deprivation [16]. AANAT1 can acetylate and inactivate monoamines in vitro [17], but the role of AANAT1 in vivo remains poorly understood. We find AANAT1 to be expressed in astrocytes and subsets of neurons in the adult Drosophila brain, with levels in astrocytes declining markedly overnight. In sleep-deprived AANAT1 mutant flies, heightened rebound sleep is accompanied by increased serotonin and dopamine levels in the brain. In neurons, AANAT1 functions to limit the quantity and consolidation of nighttime sleep, but in astrocytes AANAT1 constrains the amount of rebound sleep that flies take in response to sleep deprivation. These findings distinguish sleep-control functions of AANAT1 in neurons and astrocytes, and identify a critical role for astrocytes in the regulation of monoamine bioavailability and calibration of the response to sleep need.HighlightsThe monoamine catabolic enzyme arylalkylamine N-acetyltransferase 1 (AANAT1) is expressed by astrocytes and subsets of serotonergic, glutamatergic, GABAergic and cholinergic neurons in the adult brain of Drosophila.AANAT1 limits accumulation of serotonin and dopamine in the brain upon sleep deprivation.Loss of AANAT1 from astrocytes, but not from neurons, causes flies to increase their daytime rebound sleep in response to overnight sleep deprivation.

scholarly journals Multi-influential interactions alters behaviour and cognition through six main biological cascades in Down syndrome mouse models

2020 ◽  
Author(s):  
Arnaud Duchon ◽  
Maria del Mar Muñiz Moreno ◽  
Sandra Martin Lorenzo ◽  
Márcia Priscilla Silva de Souza ◽  
Claire Chevalier ◽  
...  
Keyword(s):  
Gene Expression ◽  
Down Syndrome ◽  
Mouse Models ◽  
Brain Function ◽  
Molecular Mechanisms ◽  
Chromosome 21 ◽  
List Type ◽  
Depth Analysis ◽  
Altered Gene

AbstractDown syndrome (DS) is the most common genetic form of intellectual disability caused by the presence of an additional copy of human chromosome 21. To provide novel insights into genotype–phenotype correlations, we screened the in vivo DS mouse library with standardized behavioural tests, magnetic resonance imaging (MRI) and hippocampal gene expression. Altogether this approach brings novel insights into the field. First, we unravelled several genetic interactions between different regions of the chromosome 21 and how they importantly contribute in altering the outcome of the phenotypes in brain function and structure. Then, in depth analysis of misregulated expressed genes involved in synaptic dysfunction highlitghed 6 biological cascades centered around DYRK1A, GSK3β, NPY, SNARE, RHOA and NPAS4. Finally, we provide a novel vision of the existing altered gene-gene crosstalk and molecular mechanisms targeting specific hubs in DS models that should become central to advance in our understanding of DS and therapies development.HighlightsBrain function and morphology changes in DS mouse models result from multiple genetic lociEach combination of loci induces specific alteration of gene expression profile in mouse modelsAltered gene expression converges to a few functional pathwys in DS mouse hippocampiThe synaptic pathway analysis leads to six connected biological cascades and defines a specific DS disease network

Mediterranean fruit fly genes exhibit different expression patterns between heat and cold treatments

2021 ◽  
pp. 1-7
Author(s):  
Kay Anantanawat ◽  
Alexie Papanicolaou ◽  
Kelly Hill ◽  
Wei Xu
Keyword(s):  
Candidate Genes ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Insect Pest ◽  
Expression Patterns ◽  
Critical Role ◽  
Cold Treatment ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Molecular Response

Abstract Invasive Tephritid fruit flies are a global threat to both agriculture and horticulture industries. Biosecurity has played a critical role in reducing their damage but becomes more and more challenging after several key chemical pesticides were banned or withdrawn for health or environmental reasons. This has led to non-chemical approaches including heat and cold treatments being broadly utilized to get rid of fruit fly infestation. However, the molecular mechanisms to kill the flies underlying these stressors are not clear yet. This knowledge will certainly help refine current post-harvest treatment strategies and develop more efficient, cost-effective and environmentally friendly approaches for fruit fly management. Previously, the molecular response of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) to heat was examined thoroughly, in which 31 key genes were identified with significant changes in expression levels and their high-resolution expression timeline was constructed across 11 timepoints. However, whether these candidate genes respond to cold in the same way was unknown. Here, a temperature bioassay was conducted and the expression profiles of these genes were investigated across the same 11 timepoints using cold treatment. The results showed that most of candidate genes exhibited divergent expression profiles compared to heat treatment, suggesting that the fly molecular response to cold may be different from those to heat. This study provides new knowledge of Tephritid fruit fly response to cold at a molecular level, which could aid in improving current fruit fly management and facilitate the development of new strategies to control this serious horticultural insect pest.

The Role of the Endothelium in Premature Atherosclerosis: Molecular Mechanisms

2020 ◽  
Vol 27 (7) ◽  
pp. 1041-1051 ◽  
Author(s):  
Michael Spartalis ◽  
Eleftherios Spartalis ◽  
Antonios Athanasiou ◽  
Stavroula A. Paschou ◽  
Christos Kontogiannis ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Low Density Lipoprotein ◽  
Critical Role ◽  
Density Lipoprotein ◽  
Number Of Genes ◽  
Causes Of Mortality ◽  
Artery Disease ◽  
Genetic And Environmental Factors ◽  
Made In

Atherosclerotic disease is still one of the leading causes of mortality. Atherosclerosis is a complex progressive and systematic artery disease that involves the intima of the large and middle artery vessels. The inflammation has a key role in the pathophysiological process of the disease and the infiltration of the intima from monocytes, macrophages and T-lymphocytes combined with endothelial dysfunction and accumulated oxidized low-density lipoprotein (LDL) are the main findings of atherogenesis. The development of atherosclerosis involves multiple genetic and environmental factors. Although a large number of genes, genetic polymorphisms, and susceptible loci have been identified in chromosomal regions associated with atherosclerosis, it is the epigenetic process that regulates the chromosomal organization and genetic expression that plays a critical role in the pathogenesis of atherosclerosis. Despite the positive progress made in understanding the pathogenesis of atherosclerosis, the knowledge about the disease remains scarce.

Molecular Mechanisms of Complement System Proteins and Matrix Metalloproteinases in the Pathogenesis of Age-Related Macular Degeneration

2019 ◽  
Vol 19 (10) ◽  
pp. 705-718 ◽  
Author(s):  
Naima Mansoor ◽  
Fazli Wahid ◽  
Maleeha Azam ◽  
Khadim Shah ◽  
Anneke I. den Hollander ◽  
...  
Keyword(s):  
Matrix Metalloproteinases ◽  
Macular Degeneration ◽  
Complement System ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Age Related Macular Degeneration ◽  
Genetic Changes ◽  
Complement System Proteins ◽  
Age Related ◽  
Common Genetic Variants

: Age-related macular degeneration (AMD) is an eye disorder affecting predominantly the older people above the age of 50 years in which the macular region of the retina deteriorates, resulting in the loss of central vision. The key factors associated with the pathogenesis of AMD are age, smoking, dietary, and genetic risk factors. There are few associated and plausible genes involved in AMD pathogenesis. Common genetic variants (with a minor allele frequency of >5% in the population) near the complement genes explain 40–60% of the heritability of AMD. The complement system is a group of proteins that work together to destroy foreign invaders, trigger inflammation, and remove debris from cells and tissues. Genetic changes in and around several complement system genes, including the CFH, contribute to the formation of drusen and progression of AMD. Similarly, Matrix metalloproteinases (MMPs) that are normally involved in tissue remodeling also play a critical role in the pathogenesis of AMD. MMPs are involved in the degradation of cell debris and lipid deposits beneath retina but with age their functions get affected and result in the drusen formation, succeeding to macular degeneration. In this review, AMD pathology, existing knowledge about the normal and pathological role of complement system proteins and MMPs in the eye is reviewed. The scattered data of complement system proteins, MMPs, drusenogenesis, and lipofusogenesis have been gathered and discussed in detail. This might add new dimensions to the understanding of molecular mechanisms of AMD pathophysiology and might help in finding new therapeutic options for AMD.

LncRNA SNHG12 Improves Cerebral Ischemic-reperfusion Injury by Activating SIRT1/FOXO3a Pathway through I nhibition of Autophagy and Oxidative Stress

2020 ◽  
Vol 17 (4) ◽  
pp. 394-401
Author(s):  
Yuanhua Wu ◽  
Yuan Huang ◽  
Jing Cai ◽  
Donglan Zhang ◽  
Shixi Liu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Molecular Mechanisms ◽  
Ischemia Reperfusion ◽  
Critical Role ◽  
Cell Activity ◽  
Ht22 Cells ◽  
Cerebral Ischemic ◽  
Cerebral Ischemic Reperfusion ◽  
And Oxidative Stress

Background: Ischemia/reperfusion (I/R) injury involves complex biological processes and molecular mechanisms such as autophagy. Oxidative stress plays a critical role in the pathogenesis of I/R injury. LncRNAs are the regulatory factor of cerebral I/R injury. Methods: This study constructs cerebral I/R model to investigate role of autophagy and oxidative stress in cerebral I/R injury and the underline regulatory mechanism of SIRT1/ FOXO3a pathway. In this study, lncRNA SNHG12 and FOXO3a expression was up-regulated and SIRT1 expression was down-regulated in HT22 cells of I/R model. Results: Overexpression of lncRNA SNHG12 significantly increased the cell viability and inhibited cerebral ischemicreperfusion injury induced by I/Rthrough inhibition of autophagy. In addition, the transfected p-SIRT1 significantly suppressed the release of LDH and SOD compared with cells co-transfected with SIRT1 and FOXO3a group and cells induced by I/R and transfected with p-SNHG12 group and overexpression of cells co-transfected with SIRT1 and FOXO3 further decreased the I/R induced release of ROS and MDA. Conclusion: In conclusion, lncRNA SNHG12 increased cell activity and inhibited oxidative stress through inhibition of SIRT1/FOXO3a signaling-mediated autophagy in HT22 cells of I/R model. This study might provide new potential therapeutic targets for further investigating the mechanisms in cerebral I/R injury and provide.

Toxicology

2017 ◽  
Author(s):  
Robert Laumbach ◽  
Michael Gochfeld
Keyword(s):  
Molecular Mechanisms ◽  
Molecular Targets ◽  
Toxicity Testing ◽  
The Body ◽  
Toxic Substances ◽  
Basic Principles ◽  
Practical Applications ◽  
Mechanisms Of Toxicity ◽  
Body Distribution ◽  
Threshold Doses

This chapter describes the basic principles of toxicology and their application to occupational and environmental health. Topics covered include pathways that toxic substances may take from sources in the environment to molecular targets in the cells of the body where toxic effects occur. These pathways include routes of exposure, absorption into the body, distribution to organs and tissues, metabolism, storage, and excretion. The various types of toxicological endpoints are discussed, along with the concepts of dose-response relationships, threshold doses, and the basis of interindividual differences and interspecies differences in response to exposure to toxic substances. The diversity of cellular and molecular mechanisms of toxicity, including enzyme induction and inhibition, oxidative stress, mutagenesis, carcinogenesis, and teratogenesis, are discussed and the chapter concludes with examples of practical applications in clinical evaluation and in toxicity testing.

scholarly journals Mechanosensation and Mechanotransduction by Lymphatic Endothelial Cells Act as Important Regulators of Lymphatic Development and Function

2021 ◽  
Vol 22 (8) ◽  
pp. 3955
Author(s):  
László Bálint ◽  
Zoltán Jakus
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Cell Fate ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Mechanical Forces ◽  
Lymphatic Endothelial Cells ◽  
Lymphatic Development ◽  
And Function ◽  
The Impact

Our understanding of the function and development of the lymphatic system is expanding rapidly due to the identification of specific molecular markers and the availability of novel genetic approaches. In connection, it has been demonstrated that mechanical forces contribute to the endothelial cell fate commitment and play a critical role in influencing lymphatic endothelial cell shape and alignment by promoting sprouting, development, maturation of the lymphatic network, and coordinating lymphatic valve morphogenesis and the stabilization of lymphatic valves. However, the mechanosignaling and mechanotransduction pathways involved in these processes are poorly understood. Here, we provide an overview of the impact of mechanical forces on lymphatics and summarize the current understanding of the molecular mechanisms involved in the mechanosensation and mechanotransduction by lymphatic endothelial cells. We also discuss how these mechanosensitive pathways affect endothelial cell fate and regulate lymphatic development and function. A better understanding of these mechanisms may provide a deeper insight into the pathophysiology of various diseases associated with impaired lymphatic function, such as lymphedema and may eventually lead to the discovery of novel therapeutic targets for these conditions.

scholarly journals The AF-6 Homolog Canoe Acts as a Rap1 Effector During Dorsal Closure of the Drosophila Embryo

Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 159-169
Author(s):  
Benjamin Boettner ◽  
Phoebe Harjes ◽  
Satoshi Ishimaru ◽  
Michael Heke ◽  
Hong Qing Fan ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Genetic Interaction ◽  
Critical Role ◽  
Adherens Junction ◽  
Small Gtpases ◽  
Drosophila Embryo ◽  
Dorsal Closure ◽  
Cell Sheets ◽  
Jnk Pathway

Abstract Rap1 belongs to the highly conserved Ras subfamily of small GTPases. In Drosophila, Rap1 plays a critical role in many different morphogenetic processes, but the molecular mechanisms executing its function are unknown. Here, we demonstrate that Canoe (Cno), the Drosophila homolog of mammalian junctional protein AF-6, acts as an effector of Rap1 in vivo. Cno binds to the activated form of Rap1 in a yeast two-hybrid assay, the two molecules colocalize to the adherens junction, and they display very similar phenotypes in embryonic dorsal closure (DC), a process that relies on the elongation and migration of epithelial cell sheets. Genetic interaction experiments show that Rap1 and Cno act in the same molecular pathway during DC and that the function of both molecules in DC depends on their ability to interact. We further show that Rap1 acts upstream of Cno, but that Rap1, unlike Cno, is not involved in the stimulation of JNK pathway activity, indicating that Cno has both a Rap1-dependent and a Rap1-independent function in the DC process.

scholarly journals Histatin-1 Attenuates LPS-Induced Inflammatory Signaling in RAW264.7 Macrophages

2021 ◽  
Vol 22 (15) ◽  
pp. 7856
Author(s):  
Sang Min Lee ◽  
Kyung-No Son ◽  
Dhara Shah ◽  
Marwan Ali ◽  
Arun Balasubramaniam ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Cytokine Production ◽  
Inflammatory Responses ◽  
Critical Role ◽  
Mapk Signaling ◽  
Response To Treatment ◽  
No Production ◽  
Inflammatory Signaling ◽  
Raw264.7 Macrophages ◽  
Inflammatory Mediator Production

Macrophages play a critical role in the inflammatory response to environmental triggers, such as lipopolysaccharide (LPS). Inflammatory signaling through macrophages and the innate immune system are increasingly recognized as important contributors to multiple acute and chronic disease processes. Nitric oxide (NO) is a free radical that plays an important role in immune and inflammatory responses as an important intercellular messenger. In addition, NO has an important role in inflammatory responses in mucosal environments such as the ocular surface. Histatin peptides are well-established antimicrobial and wound healing agents. These peptides are important in multiple biological systems, playing roles in responses to the environment and immunomodulation. Given the importance of macrophages in responses to environmental triggers and pathogens, we investigated the effect of histatin-1 (Hst1) on LPS-induced inflammatory responses and the underlying molecular mechanisms in RAW264.7 (RAW) macrophages. LPS-induced inflammatory signaling, NO production and cytokine production in macrophages were tested in response to treatment with Hst1. Hst1 application significantly reduced LPS-induced NO production, inflammatory cytokine production, and inflammatory signaling through the JNK and NF-kB pathways in RAW cells. These results demonstrate that Hst1 can inhibit LPS-induced inflammatory mediator production and MAPK signaling pathways in macrophages.

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