scholarly journals Altered actin filament dynamics in theDrosophilamushroom bodies lead to fast acquisition of alcohol consumption preference

2019 ◽  
Author(s):  
Andrew R. Butts ◽  
Shamsideen A. Ojelade ◽  
Alexandra Seguin ◽  
Collin B. Merrill ◽  
Aylin R. Rodan ◽  
...  
Keyword(s):  
Alcohol Consumption ◽  
Alcohol Use ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
The United States ◽  
Alcohol Preference ◽  
Dominant Negative ◽  
Actin Dynamics ◽  
Self Administration

AbstractAlcohol use is highly prevalent in the United States and across the world, and every year millions of people suffer from alcohol use disorders (AUDs). While the genetic contribution to developing AUDs is estimated to be 50-60%, many of the underlying molecular mechanisms remain unclear. Previous studies from our lab revealed thatDrosophilalacking RhoGAP18B and Ras Suppressor 1 (Rsu1) display reduced sensitivity to ethanol-induced sedation. Both Rsu1 and RhoGAP18B are negative regulators of the small Rho-family GTPase, Rac1, a modulator of actin dynamics. Here we investigate the role of Rac1 and its downstream target, the actin-severing protein cofilin, in alcohol consumption preference. We show that these two regulators of actin dynamics can alter experience-dependent alcohol preference in a bidirectional manner: expressing either activated Rac1 or dominant-negative cofilin in the mushroom bodies (MB) abolishes experience-dependent alcohol preference. Conversely, dominant-negative Rac1 or activated cofilin MB expression lead to faster acquisition of alcohol preference. Our data show that Rac1 and cofilin activity are key to determining the rate of acquisition of alcohol preference, revealing a critical role of actin dynamics regulation in the development of voluntary self-administration inDrosophila.Significance StatementThe risks for developing an alcohol use disorder (AUD) are strongly determined by genetic factors. Understanding the genes and molecular mechanisms that contribute to that risk is therefore a necessary first step for the development of targeted therapeutic intervention. Here we show that regulators of actin cytoskeleton dynamics can bidirectionally determine the acquisition rate of alcohol self-administration, highlighting this process as a key mechanism contributing to the risk of AUD development.

ADF/n-cofilin–dependent actin turnover determines platelet formation and sizing

Blood ◽  
2010 ◽  
Vol 116 (10) ◽  
pp. 1767-1775 ◽  
Author(s):  
Markus Bender ◽  
Anita Eckly ◽  
John H. Hartwig ◽  
Margitta Elvers ◽  
Irina Pleines ◽  
...  
Keyword(s):  
Actin Filament ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Actin Dynamics ◽  
Complex Process ◽  
First Time ◽  
Late Stages ◽  
Platelet Formation

Abstract The cellular and molecular mechanisms orchestrating the complex process by which bone marrow megakaryocytes form and release platelets remain poorly understood. Mature megakaryocytes generate long cytoplasmic extensions, proplatelets, which have the capacity to generate platelets. Although microtubules are the main structural component of proplatelets and microtubule sliding is known to drive proplatelet elongation, the role of actin dynamics in the process of platelet formation has remained elusive. Here, we tailored a mouse model lacking all ADF/n-cofilin–mediated actin dynamics in megakaryocytes to specifically elucidate the role of actin filament turnover in platelet formation. We demonstrate, for the first time, that in vivo actin filament turnover plays a critical role in the late stages of platelet formation from megakaryocytes and the proper sizing of platelets in the periphery. Our results provide the genetic proof that platelet production from megakaryocytes strictly requires dynamic changes in the actin cytoskeleton.

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.

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.

Alcohol Dependence Conceptualized as a Stress Disorder

2019 ◽  
pp. 198-220
Author(s):  
Leandro F. Vendruscolo ◽  
George F. Koob
Keyword(s):  
Prefrontal Cortex ◽  
Alcohol Use ◽  
Alcohol Dependence ◽  
Glucocorticoid Receptors ◽  
Critical Role ◽  
Emotional States ◽  
Brain Circuits ◽  
Negative Emotional State ◽  
Alcohol Alcohol

Alcohol use disorder is a chronically relapsing disorder that involves (1) compulsivity to seek and take alcohol, (2) difficulty in limiting alcohol intake, and (3) emergence of a negative emotional state (e.g., dysphoria, anxiety, irritability) in the absence of alcohol. Alcohol addiction encompasses a three-stage cycle that becomes more intense as alcohol use progresses: binge/intoxication, withdrawal/negative affect, and preoccupation/anticipation. These stages engage neuroadaptations in brain circuits that involve the basal ganglia (reward hypofunction), extended amygdala (stress sensitization), and prefrontal cortex (executive function disorder). This chapter discusses key neuroadaptations in the hypothalamic and extrahypothalamic stress systems and the critical role of glucocorticoid receptors. These neuroadaptations contribute to negative emotional states that powerfully drive compulsive alcohol drinking and seeking. These changes in association with a disruption of prefrontal cortex function that lead to cognitive deficits and poor decision making contribute to the chronic relapsing nature of alcohol dependence.

scholarly journals The laterodorsal tegmentum-ventral tegmental area circuit controls depression-like behaviors by activating ErbB4 in DA neurons

2021 ◽  
Author(s):  
Hongsheng Wang ◽  
Wanpeng Cui ◽  
Wenbing Chen ◽  
Fang Liu ◽  
Zhaoqi Dong ◽  
...  
Keyword(s):  
Ventral Tegmental Area ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Coping With Stress ◽  
Chemical Genetic ◽  
Chronic Social Defeat Stress ◽  
Ventral Tegmental ◽  
Laterodorsal Tegmentum ◽  
Specific Deletion

AbstractDopamine (DA) neurons in the ventral tegmental area (VTA) are critical to coping with stress. However, molecular mechanisms regulating their activity and stress-induced depression were not well understood. We found that the receptor tyrosine kinase ErbB4 in VTA was activated in stress-susceptible mice. Deleting ErbB4 in VTA or in DA neurons, or chemical genetic inhibition of ErbB4 kinase activity in VTA suppressed the development of chronic social defeat stress (CSDS)-induced depression-like behaviors. ErbB4 activation required the expression of NRG1 in the laterodorsal tegmentum (LDTg); LDTg-specific deletion of NRG1 inhibited depression-like behaviors. NRG1 and ErbB4 suppressed potassium currents of VTA DA neurons and increased their firing activity. Finally, we showed that acute inhibition of ErbB4 after stress attenuated DA neuron hyperactivity and expression of depression-like behaviors. Together, these observations demonstrate a critical role of NRG1-ErbB4 signaling in regulating depression-like behaviors and identify an unexpected mechanism by which the LDTg-VTA circuit regulates the activity of DA neurons.

scholarly journals Suppression of eNOS-derived superoxide by caveolin-1: a biopterin-dependent mechanism

2011 ◽  
Vol 301 (3) ◽  
pp. H903-H911 ◽  
Author(s):  
Kanchana Karuppiah ◽  
Lawrence J. Druhan ◽  
Chun-an Chen ◽  
Travis Smith ◽  
Jay L. Zweier ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Oxidase Activity ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Caveolin 1 ◽  
Calcium Calmodulin Dependent ◽  
Enos Uncoupling ◽  
Nadph Oxidation ◽  
Interfering Rna

In the vasculature, nitric oxide (NO) is generated by endothelial NO synthase (eNOS) in a calcium/calmodulin-dependent reaction. In the absence of the requisite eNOS cofactor tetrahydrobiopterin (BH4), NADPH oxidation is uncoupled from NO generation, leading to the production of superoxide. Although this phenomenon is apparent with purified enzyme, cellular studies suggest that formation of the BH4 oxidation product, dihydrobiopterin, is the molecular trigger for eNOS uncoupling rather than BH4 depletion alone. In the current study, we investigated the effects of both BH4 depletion and oxidation on eNOS-derived superoxide production in endothelial cells in an attempt to elucidate the molecular mechanisms regulating eNOS oxidase activity. Results demonstrated that pharmacological depletion of endothelial BH4 does not result in eNOS oxidase activity, whereas BH4 oxidation gave rise to significant eNOS-oxidase activity. These findings suggest that the endothelium possesses regulatory mechanisms, which prevent eNOS oxidase activity from pterin-free eNOS. Using a combination of gene silencing and pharmacological approaches, we demonstrate that eNOS-caveolin-1 association is increased under conditions of reduced pterin bioavailability and that this sequestration serves to suppress eNOS uncoupling. Using small interfering RNA approaches, we demonstrate that caveolin-1 gene silencing increases eNOS oxidase activity to 85% of that observed under conditions of BH4 oxidation. Moreover, when caveolin-1 silencing was combined with a pharmacological inhibitor of AKT, BH4 depletion increased eNOS-derived superoxide to 165% of that observed with BH4 oxidation. This study identifies a critical role of caveolin-1 in the regulation of eNOS uncoupling and provides new insight into the mechanisms through which disease-associated changes in caveolin-1 expression may contribute to endothelial dysfunction.

scholarly journals The Emerging Role of Glucagon-like Peptide-1 Receptor Agonists for the Management of NAFLD

2021 ◽  
Author(s):  
Chandani Patel Chavez ◽  
Kenneth Cusi ◽  
Sushma Kadiyala
Keyword(s):  
Evidence Synthesis ◽  
Clinical Care ◽  
Treatment Options ◽  
Critical Role ◽  
Risk Groups ◽  
The United States ◽  
Multidisciplinary Teams ◽  
Consensus Statements ◽  
Meta Analyses

Abstract Context The burden of cirrhosis from NAFLD is reaching epidemic proportions in the United States. This calls for greater awareness among endocrinologists, who often see but may miss the diagnosis in adults with obesity or type 2 diabetes mellitus (T2D) who are at the highest risk. At the same time, recent studies suggest that GLP-1RAs are beneficial versus steatohepatitis (NASH) in this population. This minireview aims to assist endocrinologists to recognize the condition and recent work on the role of GLP-1RAs in NAFLD/NASH. Evidence acquisition Evidence from observational studies, randomized controlled trials, and meta-analyses. Evidence Synthesis Endocrinologists should lead multidisciplinary teams to implement recent consensus statements on NAFLD that call for screening and treatment of clinically significant fibrosis to prevent cirrhosis, especially in the high-risk groups (i.e., people with obesity, prediabetes or T2D). With no FDA-approved agents, weight loss is central to their successful management, with pharmacological treatment options limited today to vitamin E (in people without T2D) and diabetes medications that reverse steatohepatitis, such as pioglitazone or GLP-1RA. Recently the benefit of GLP-1RAs in NAFLD, suggested from earlier trials, has been confirmed in adults with biopsy-proven NASH. In 2021, the FDA also approved semaglutide for obesity management. Conclusion A paradigm change is developing between the endocrinologist’s greater awareness about their critical role to curve the epidemic of NAFLD and new clinical care pathways that include a broader use of GLP-1RAs in the management of these complex patients.

scholarly journals Single-Cell Transcriptomic Analysis Revealed a Critical Role of SPP1/CD44-Mediated Crosstalk Between Macrophages and Cancer Cells in Glioma

2021 ◽  
Vol 9 ◽  
Author(s):  
Cong He ◽  
Luoyan Sheng ◽  
Deshen Pan ◽  
Shuai Jiang ◽  
Li Ding ◽  
...  
Keyword(s):  
Single Cell ◽  
Tumor Heterogeneity ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Cell Communication ◽  
High Grade Glioma ◽  
Sequencing Analysis ◽  
High Grade ◽  
Cellular Components

High-grade glioma is one of the most lethal human cancers characterized by extensive tumor heterogeneity. In order to identify cellular and molecular mechanisms that drive tumor heterogeneity of this lethal disease, we performed single-cell RNA sequencing analysis of one high-grade glioma. Accordingly, we analyzed the individual cellular components in the ecosystem of this tumor. We found that tumor-associated macrophages are predominant in the immune microenvironment. Furthermore, we identified five distinct subpopulations of tumor cells, including one cycling, two OPC/NPC-like and two MES-like cell subpopulations. Moreover, we revealed the evolutionary transition from the cycling to OPC/NPC-like and MES-like cells by trajectory analysis. Importantly, we found that SPP1/CD44 interaction plays a critical role in macrophage-mediated activation of MES-like cells by exploring the cell-cell communication among all cellular components in the tumor ecosystem. Finally, we showed that high expression levels of both SPP1 and CD44 correlate with an increased infiltration of macrophages and poor prognosis of glioma patients. Taken together, this study provided a single-cell atlas of one high-grade glioma and revealed a critical role of macrophage-mediated SPP1/CD44 signaling in glioma progression, indicating that the SPP1/CD44 axis is a potential target for glioma treatment.

scholarly journals Maternal Hepcidin Suppression Is Essential for Healthy Pregnancy

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 43-44
Author(s):  
Veena Sangkhae ◽  
Tomas Ganz ◽  
Elizabeta Nemeth
Keyword(s):  
Iron Deficiency ◽  
Molecular Mechanisms ◽  
Hematological Parameters ◽  
Critical Role ◽  
Physiological Mechanism ◽  
Deficiency Anemia ◽  
Private Company ◽  
Iron Stores ◽  
Primary Mouse

Iron is essential for maternal and fetal health during pregnancy, and iron requirements increase substantially in the second half of gestation1. However, the molecular mechanisms ensuring increased iron availability during pregnancy are not well understood. Hepcidin is the key iron-regulatory hormone and functions by occluding and degrading the iron exporter ferroportin (FPN) to inhibit dietary iron absorption and mobilization of iron from stores. In healthy human and rodent pregnancies, maternal hepcidin decreases starting in the second trimester and is nearly undetectable by late pregnancy2,3 (Figure A). We explored the role of maternal and embryo hepcidin in regulating embryo iron endowment using mouse models. By generating combinations of dams and embryos lacking hepcidin or not, we showed that in normal mouse pregnancy, only maternal but not embryo or placental hepcidin determines embryo iron endowment4. Maternal hepcidin was inversely related to embryo iron stores, and embryos from hepcidin-deficient dams had significantly higher hepatic iron stores regardless of their own hepcidin genotype. When maternal hepcidin was elevated during the second half of pregnancy in mice by administering a hepcidin mimetic, this led to dose-dependent embryo iron deficiency, anemia, and in severe cases, embryo death4. Embryos were particularly sensitive to maternal iron restriction as they developed iron deficiency in the liver and the brain even when maternal hematological parameters were unaffected. These data highlight the critical role of maternal hepcidin suppression for heathy pregnancy. Yet, the physiological mechanism of maternal hepcidin suppression remains unknown. We showed in mice that maternal hepcidin decreases prior to a significant decrease in liver iron and without any changes in serum iron, suggesting that maternal hepcidin suppression is not driven solely by iron deficiency. Using an in vitro model, we determined that the placenta secretes a hepcidin-suppressing factor. Exposure of primary mouse hepatocytes to supernatants from cultured human placenta cells, but not control media, suppressed hepcidin mRNA more than 10-fold (Figure B) and for up to 48hrs. The suppressive factor in the supernatant was >100kDa in size and not associated with exosomes. Studies to identify the placenta-derived hepcidin suppressor are ongoing. In summary, suppression of maternal hepcidin is essential to ensure adequate iron supply for transfer to the fetus and for the increase in maternal red blood cell mass2, and a placenta-derived hepcidin suppressor likely plays an important role in this adaptation. 1Fisher AL and Nemeth E, Am J Clin Nutr, 2017 2Sangkhae V et al, JCI, 2020 3van Santen S et al, Clin Chem Lab Med, 2013 4Sangkhae V et al, Blood, 2020 Figure 1 Disclosures Ganz: Global Blood Therapeutics: Consultancy; Ionis Pharmaceuticals: Consultancy; American Regent: Consultancy; Rockwell: Consultancy; Vifor: Consultancy; Astellas: Consultancy; Akebia: Consultancy; Gossamer Bio: Consultancy; Silarus Therapeutics: Current equity holder in private company; Sierra Oncology: Consultancy; Ambys: Consultancy; Disc Medicine: Consultancy; Intrinsic LifeSciences: Current equity holder in private company. Nemeth:Intrinsic LifeSciences: Current equity holder in private company; Silarus Therapeutics: Current equity holder in private company; Ionis Pharmaceuticals: Consultancy; Protagonist: Consultancy; Vifor: Consultancy.

Sign in / Sign up

Export Citation Format

Share Document