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Found 37769 matches. Displaying 1751-1760
Woods C, Marques-Lopes J, Contoreggi NH, Milner TA, Pickel VM, Wang G, Glass MJ
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Tumor Necrosis Factor alpha Receptor Type 1 Activation in the Hypothalamic Paraventricular Nucleus Contributes to Glutamate Signaling and Angiotensin II-Dependent Hypertension

JOURNAL OF NEUROSCIENCE 2021 FEB 10; 41(6):1349-1362
There are significant neurogenic and inflammatory influences on blood pressure, yet the role played by each of these processes in the development of hypertension is unclear. Tumor necrosis factor alpha (TNF alpha) has emerged as a critical modulator of blood pressure and neural plasticity; however, the mechanism by which TNF alpha signaling contributes to the development of hypertension is uncertain. We present evidence that following angiotensin H (AngII) infusion the TNF alpha type 1 receptor (TNFR1) plays a key role in heightened glutamate signaling in the hypothalamic paraventricular nucleus (PVN), a key central coordinator of blood pressure control. Fourteen day administration of a slow-pressor dose of AngII in male mice was associated with transcriptional and post-transcriptional (increased plasma membrane affiliation) regulation of TNFR1 in the PVN. Further, TNFR1 was shown to be critical for elevated NMDA-mediated excitatory currents in sympathoexcitatory PVN neurons following AngII infusion. Finally, silencing PVN TNFR1 prevented the increase in systolic blood pressure induced by AngII. These findings indicate that TNFR1 modulates a cellular pathway involving an increase in NMDA-mediated currents in the PVN following AngII infusion, suggesting a mechanism whereby TNFR1 activation contributes to hypertension via heightened hypothalamic glutamate-dependent signaling.
Anderson TL, Sheppard LW, Walter JA, Rolley RE, Reuman DC
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Synchronous effects produce cycles in deer populations and deer-vehicle collisions

ECOLOGY LETTERS 2021; 24(2):337-347
Population cycles are fundamentally linked with spatial synchrony, the prevailing paradigm being that populations with cyclic dynamics are easily synchronised. That is, population cycles help give rise to spatial synchrony. Here we demonstrate this process can work in reverse, with synchrony causing population cycles. We show that timescale-specific environmental effects, by synchronising local population dynamics on certain timescales only, cause major population cycles over large areas in white-tailed deer. An important aspect of the new mechanism is specificity of synchronising effects to certain timescales, which causes local dynamics to sum across space to a substantial cycle on those timescales. We also demonstrate, to our knowledge for the first time, that synchrony can be transmitted not only from environmental drivers to populations (deer), but also from there to human systems (deer-vehicle collisions). Because synchrony of drivers may be altered by climate change, changes to population cycles may arise via our mechanism.
Shonkoff JP, Boyce WT, Levitt P, Martinez FD, McEwen B
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Leveraging the Biology of Adversity and Resilience to Transform Pediatric Practice

PEDIATRICS 2021 FEB; 147(2):? Article e20193845
Advances in science are fundamentally changing the way we understand how inextricable interactions among genetic predispositions, physical and social environments, and developmental timing influence early childhood development and the foundations of health and how significant early adversity can lead to a lifetime of chronic health impairments. This article and companion article illustrate the extent to which differential outcomes are shaped by ongoing interactive adaptations to context that begin at or even before conception and continue throughout life, with increasing evidence pointing to the importance of the prenatal period and early infancy for the developing brain, the immune system, and metabolic regulation. Although new discoveries in the basic sciences are transforming tertiary medical care and producing breakthrough outcomes in treating disease, this knowledge is not being leveraged effectively to inform new approaches to promoting whole-child development and preventing illness. The opportunity for pediatrics to serve as the leading edge of science-based innovation across the early childhood ecosystem has never been more compelling. In this article, we present a framework for leveraging the frontiers of scientific discovery to inform new strategies in pediatric practice and advocacy to protect all developing biological systems from the disruptive effects of excessive early adversity beyond providing information on child development for parents and enriched learning experiences for young children.
Scotchman E, Kume K, Navarro FJ, Nurse P
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Identification of mutants with increased variation in cell size at onset of mitosis in fission yeast

JOURNAL OF CELL SCIENCE 2021 FEB; 134(3):? Article jcs251769
Fission yeast cells divide at a similar cell length with little variation about the mean. This is thought to be the result of a control mechanism that senses size and corrects for any deviations by advancing or delaying onset of mitosis. Gene deletions that advance cells into mitosis at a smaller size or delay cells entering mitosis have led to the identification of genes potentially involved in this mechanism. However, the molecular basis of this control is still not understood. In this work, we have screened for genes that when deleted increase the variability in size of dividing cells. The strongest candidate identified in this screen was mga2. The mga2 deletion strain shows a greater variation in cell length at division, with a coefficient of variation (CV) of 15-24%, while the wild-type strain has a CVof 5-8%. Furthermore, unlike wild-type cells, the mga2 deletion cells are unable to correct cell size deviations within one cell cycle. We show that the mga2 gene genetically interacts with nem1 and influences the nuclear membrane and the nuclear-cytoplasmic transport of CDK regulators.
Ostadi V, Sherkat R, Migaud M, Modaressadeghi SM, Casanova JL, Puel A, Nekooie-Marnany N, Ganjalikhani-Hakemi M
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Functional analysis of two STAT1 gain-of-function mutations in two Iranian families with autosomal dominant chronic mucocutaneous candidiasis

MEDICAL MYCOLOGY 2021 FEB; 59(2):180-188
Candidiasis is characterized by susceptibility to recurrent or persistent infections caused by Candida spp., typically Candida albicans, of cutaneous and mucosal surfaces. In this report, function and frequency of Th17 cells as well as genetics of patients susceptible to mucocutaneous candidiasis were studied. For patients, T-cell proliferation tests in response to Candida antigen, Th17 cell proportions, and STAT1 phosphorylation were evaluated through flow cytometry. Expression of IL17A, IL17F and IL22 genes were measured by real-time quantitative PCR. At the same time, whole exome sequencing was performed for all patients. We identified two heterozygous substitutions, one: c.821G > A (p. R274Q) was found in a multiplex family with three individuals affected, the second one: c.812A > C (p. Q271P) was found in a sporadic case. Both mutations are located in the coiled-coil domain (CCD) of STAT1. The frequency of Th17 cells, IL17A, IL17F, and IL22 gene expression in patients' peripheral blood mononuclear cells (PBMCs), and T-cell proliferation to Candida antigens were significantly reduced in the patients as compared to healthy controls. An increased STAT1 phosphorylation was observed in patients' PBMCs upon interferon (IFN)-gamma stimulation as compared to healthy controls. We report two different but neighboring heterozygous mutations, located in exon 10 of the STAT1 gene, in four Iranian patients with CMC, one of whom also had hypothyroidism. These mutations were associated with impaired T cell proliferation to Candida antigen, low Th17 cell proportions, and increased STAT1 phosphorylation upon IFN-gamma. We suggest that interfering with STAT1 phosphorylation might be a promising way for potential therapeutic measurements for such patients.
Zhang YX, Daday C, Gu RX, Cox CD, Martinac B, de Groot BL, Walz T
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Visualization of the mechanosensitive ion channel MscS under membrane tension

NATURE 2021 FEB 18; 590(7846):509-514
Mechanosensitive channels sense mechanical forces in cell membranes and underlie many biological sensing processes(1-3). However, how exactly they sense mechanical force remains under investigation(4). The bacterial mechanosensitive channel of small conductance, MscS, is one of the most extensively studied mechanosensitive channels(4-8), but how it is regulated by membrane tension remains unclear, even though the structures are known for its open and closed states(9-11). Here we used cryo-electron microscopy to determine the structure of MscS in different membrane environments, including one that mimics a membrane under tension. We present the structures of MscS in the subconducting and desensitized states, and demonstrate that the conformation of MscS in a lipid bilayer in the open state is dynamic. Several associated lipids have distinct roles in MscS mechanosensation. Pore lipids are necessary to prevent ion conduction in the closed state. Gatekeeper lipids stabilize the closed conformation and dissociate with membrane tension, allowing the channel to open. Pocket lipids in a solvent-exposed pocket between subunits are pulled out under sustained tension, allowing the channel to transition to the subconducting state and then to the desensitized state. Our results provide a mechanistic underpinning and expand on the 'force-from-lipids' model for MscS mechanosensation(4,11). The authors report the structural characterization of the mechanically activated channel MscS in different membrane environments and show how the mechanosensation of MscS can be visualized.
Boyce WT, Levitt P, Martinez FD, McEwen BS, Shonkoff JP
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Genes, Environments, and Time: The Biology of Adversity and Resilience

PEDIATRICS 2021 FEB; 147(2):? Article e20201651
Exposures to adverse environments, both psychosocial and physicochemical, are prevalent and consequential across a broad range of childhood populations. Such adversity, especially early in life, conveys measurable risk to learning and behavior and to the foundations of both mental and physical health. Using an interactive gene-environment-time (GET) framework, we survey the independent and interactive roles of genetic variation, environmental context, and developmental timing in light of advances in the biology of adversity and resilience, as well as new discoveries in biomedical research. Drawing on this rich evidence base, we identify 4 core concepts that provide a powerful catalyst for fresh thinking about primary health care for young children: (1) all biological systems are inextricably integrated, continuously "reading" and adapting to the environment and "talking back" to the brain and each other through highly regulated channels of cross-system communication; (2) adverse environmental exposures induce alterations in developmental trajectories that can lead to persistent disruptions of organ function and structure; (3) children vary in their sensitivity to context, and this variation is influenced by interactions among genetic factors, family and community environments, and developmental timing; and (4) critical or sensitive periods provide unmatched windows of opportunity for both positive and negative influences on multiple biological systems. These rapidly moving frontiers of investigation provide a powerful framework for new, science-informed thinking about health promotion and disease prevention in the early childhood period. Advances in biology provide a platform for fresh thinking about health promotion and disease prevention in the early childhood period.
Nagai J, Yu XZ, Papouin T, Cheong EJ, Freeman MR, Monk KR, Hastings MH, Haydon PG, Rowitch D, Shaham S, Khakh BS
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Behaviorally consequential astrocytic regulation of neural circuits

NEURON 2021 FEB 17; 109(4):576-596
Astrocytes are a large and diverse population of morphologically complex cells that exist throughout nervous systems of multiple species. Progress over the last two decades has shown that astrocytes mediate developmental, physiological, and pathological processes. However, a long-standing open question is how astrocytes regulate neural circuits in ways that are behaviorally consequential. In this regard, we summarize recent studies using Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, and Mus musculus. The data reveal diverse astrocyte mechanisms operating in seconds or much longer timescales within neural circuits and shaping multiple behavioral outputs. We also refer to human diseases that have a known primary astrocytic basis. We suggest that including astrocytes in mechanistic, theoretical, and computational studies of neural circuits provides new perspectives to understand behavior, its regulation, and its disease-related Astrocytes are a large and diverse population of morphologically complex cells that exist throughout nervous systems of multiple species. Progress over the last two decades has shown that astrocytes mediate developmental, physiological, and pathological processes. However, a long-standing open question is how astrocytes regulate neural circuits in ways that are behaviorally consequential. In this regard, we summarize recent studies using Caenorhabditis elegans, Drosophila melanogaster, Danio rerio, and Mus musculus. The data reveal diverse astrocyte mechanisms operating in seconds or much longer timescales within neural circuits and shaping multiple behavioral outputs. We also refer to human diseases that have a known primary astrocytic basis. We suggest that including astrocytes in mechanistic, theoretical, and computational studies of neural circuits provides new perspectives to understand behavior, its regulation, and its disease-related manifestations.
Sahasrabudhe A, Begum F, Guevara CA, Morrison C, Hsiao KF, Kezunovic N, Bozdagi-Gunal O, Benson DL
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Cyfip1 Regulates SynGAP1 at Hippocampal Synapses

FRONTIERS IN SYNAPTIC NEUROSCIENCE 2021 FEB 5; 12(?):? Article 581714
In humans, copy number variations in CYFIP1 appear to have sweeping physiological and structural consequences in the brain, either producing or altering the severity of intellectual disability, autism, and schizophrenia. Independently, SynGAP1 haploinsufficiency produces intellectual disability and, frequently, autism. Cyfip1 inhibits protein translation and promotes actin polymerization, and SynGAP1 is a synaptically localized Ras/Rap GAP. While these proteins are clearly distinct, studies investigating their functions in mice have shown that each regulates the maturation of synapses in the hippocampus and haploinsufficiency for either produces an exaggerated form of mGluR-dependent long-term depression, suggesting that some signaling pathways converge. In this study, we examined how Cyfip1 haploinsufficiency impacts SynGAP1 levels and localization, as well as potential sites for mechanistic interaction in mouse hippocampus. The data show that synaptic, but not total, levels of SynGAP1 in Cyfip1(+/-) mice were abnormally low during early postnatal development and in adults. This may be in response to a shift in the balance of kinases that activate SynGAP1 as levels of Cdk5 were reduced and those of activated CaMKII were maintained in Cyfip1(+/-) mice compared to wild-type mice. Alternatively, this could reflect altered actin dynamics as Rac1 activity in Cyfip1(+/-) hippocampus was boosted significantly compared to wild-type mice, and levels of synaptic F-actin were generally enhanced due in part to an increase in the activity of the WAVE regulatory complex. Decreased synaptic SynGAP1 coupled with a CaMKII-mediated bias toward Rap1 inactivation at synapses is also consistent with increased levels of synaptic GluA2, increased AMPA receptor-mediated responses to stimulation, and increased levels of synaptic mGluR1/5 compared to wild-type mice. Collectively, our data suggest that Cyfip1 regulates SynGAP1 and the two proteins work coordinately at synapses to appropriately direct actin polymerization and GAP activity.
Moura-Assis A, Friedman JM, Velloso LA
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Gut-to-brain signals in feeding control

AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM 2021 FEB; 320(2):E326-E332
Interoceptive signals from gut and adipose tissue and sensory cues from the environment are integrated by hubs in the brain to regulate feeding behavior and maintain homeostatic control of body weight. In vivo neural recordings have revealed that these signals control the activity of multiple layers of hunger neurons and eating is not only the result of feedback correction to a set point, but can also be under the influence of anticipatory regulations. A series of recent technical developments have revealed how peripheral and sensory signals, in particular, from the gut are conveyed to the brain to integrate neural circuits. Here, we describe the mechanisms involved in gastrointestinal stimulation by nutrients and how these signals act on the hindbrain to generate motivated behaviors. We also consider the organization of multidirectional intra- and extrahypothalamic circuits and how this has created a framework for understanding neural control of feeding.