scholarly journals DDX24, a D-E-A-D box RNA helicase, is required for muscle fiber organization and anterior pole specification essential for head regeneration in planarians

2021 ◽  
Author(s):  
Souradeep R. Sarkar ◽  
Vinay Kumar Dubey ◽  
Anusha Jahagirdar ◽  
Vairavan Lakshmanan ◽  
Mohamed Mohamed Haroon ◽  
...  
Keyword(s):  
Muscle Fiber ◽  
Positional Information ◽  
Rna Helicase ◽  
Whole Body ◽  
Rnai Phenotype ◽  
Anterior Pole ◽  
80S Ribosome ◽  
Head Regeneration ◽  
Fiber Organization

ABSTRACTPlanarians have a remarkable ability to undergo whole-body regeneration. The timely establishment of polarity at the wound site followed by the specification of the organizing centers- the anterior pole and the posterior pole, are indispensable for successful regeneration. In planarians, polarity, pole, and positional-information determinants are predominantly expressed by muscles. The molecular toolkit that enables this functionality of planarian muscles however remains poorly understood. Here we report that SMED_DDX24, a D-E-A-D Box RNA helicase and the homolog of human DDX24, is critical for planarian head regeneration. DDX24 is enriched in muscles and its knockdown leads to defective muscle-fiber organization and failure to re-specify anterior pole/organizer. Overall, loss of DDX24 manifests into gross misregulation of many well-characterized positional-control genes and patterning-control genes, necessary for organogenesis and tissue positioning and tissue patterning. In addition, wound-induced Wnt signalling was also upregulated in ddx24 RNAi animals. Canonical WNT-βCATENIN signalling is known to suppress head identity throughout bilateria, including planarians. Modulating this Wnt activity by β-catenin-1 RNAi, the effector molecule of this pathway, partially rescues the ddx24 RNAi phenotype, implying that a high Wnt environment in ddx24 knockdown animals likely impedes their normal head regeneration. Furthermore, at a sub-cellular level, RNA helicases are known to regulate muscle mass and function by regulating their translational landscape. ddx24 knockdown leads to the downregulation of large subunit ribosomal RNA and the 80S ribosome peak, implying its role in ribosome biogenesis and thereby influencing the translational output. This aspect seems to be an evolutionarily conserved role of DDX24. In summary, our work demonstrates the role of a D-E-A-D box RNA helicase in whole-body regeneration through muscle fiber organization, and pole and positional-information re-specification, likely mediated through translation regulation.

scholarly journals activin-2 is required for regeneration of polarity on the planarian anterior-posterior axis

PLoS Genetics ◽  
2021 ◽  
Vol 17 (3) ◽  
pp. e1009466
Author(s):  
Jennifer K. Cloutier ◽  
Conor L. McMann ◽  
Isaac M. Oderberg ◽  
Peter W. Reddien
Keyword(s):  
Muscle Cells ◽  
Positional Information ◽  
Whole Body ◽  
Tail Regeneration ◽  
Activin Signaling ◽  
Wound Induction ◽  
Induced Genes ◽  
Asymmetric Activation ◽  
Head Regeneration ◽  
Anterior Posterior

Planarians are flatworms and can perform whole-body regeneration. This ability involves a mechanism to distinguish between anterior-facing wounds that require head regeneration and posterior-facing wounds that require tail regeneration. How this head-tail regeneration polarity decision is made is studied to identify principles underlying tissue-identity specification in regeneration. We report that inhibition of activin-2, which encodes an Activin-like signaling ligand, resulted in the regeneration of ectopic posterior-facing heads following amputation. During tissue turnover in uninjured planarians, positional information is constitutively expressed in muscle to maintain proper patterning. Positional information includes Wnts expressed in the posterior and Wnt antagonists expressed in the anterior. Upon amputation, several wound-induced genes promote re-establishment of positional information. The head-versus-tail regeneration decision involves preferential wound induction of the Wnt antagonist notum at anterior-facing over posterior-facing wounds. Asymmetric activation of notum represents the earliest known molecular distinction between head and tail regeneration, yet how it occurs is unknown. activin-2 RNAi animals displayed symmetric wound-induced activation of notum at anterior- and posterior-facing wounds, providing a molecular explanation for their ectopic posterior-head phenotype. activin-2 RNAi animals also displayed anterior-posterior (AP) axis splitting, with two heads appearing in anterior blastemas, and various combinations of heads and tails appearing in posterior blastemas. This was associated with ectopic nucleation of anterior poles, which are head-tip muscle cells that facilitate AP and medial-lateral (ML) pattern at posterior-facing wounds. These findings reveal a role for Activin signaling in determining the outcome of AP-axis-patterning events that are specific to regeneration.

280-LB: Role of A1 and A3 Adenosine Receptors in Whole Body Glucose Metabolism

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 280-LB ◽  
Author(s):  
SHANU JAIN ◽  
DILIP K. TOSH ◽  
MARC REITMAN ◽  
KENNETH A. JACOBSON
Keyword(s):  
Glucose Metabolism ◽  
Adenosine Receptors ◽  
Whole Body

Determinants of maximal whole-body fat oxidation in elite cross-country skiers: Role of skeletal muscle mitochondria

2018 ◽  
Vol 28 (12) ◽  
pp. 2494-2504 ◽  
Author(s):  
Sune Dandanell ◽  
Anne-Kristine Meinild-Lundby ◽  
Andreas B. Andersen ◽  
Paul F. Lang ◽  
Laura Oberholzer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Body Fat ◽  
Fat Oxidation ◽  
Whole Body ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria ◽  
Cross Country

scholarly journals Insights into the Structure of Dimeric RNA Helicase CsdA and Indispensable Role of Its C-Terminal Regions

Structure ◽  
2017 ◽  
Vol 25 (12) ◽  
pp. 1795-1808.e5 ◽  
Author(s):  
Ling Xu ◽  
Lijun Wang ◽  
Junhui Peng ◽  
Fudong Li ◽  
Lijie Wu ◽  
...  
Keyword(s):  
Rna Helicase

scholarly journals RNA Helicase A Regulates the Replication of RNA Viruses

Viruses ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 361
Author(s):  
Rui-Zhu Shi ◽  
Yuan-Qing Pan ◽  
Li Xing
Keyword(s):  
Virus Replication ◽  
Rna Binding ◽  
Rna Viruses ◽  
Rna Helicase ◽  
Rna Helicase A ◽  
Double Stranded Rna ◽  
Binding Domains ◽  
N Terminus

The RNA helicase A (RHA) is a member of DExH-box helicases and characterized by two double-stranded RNA binding domains at the N-terminus. RHA unwinds double-stranded RNA in vitro and is involved in RNA metabolisms in the cell. RHA is also hijacked by a variety of RNA viruses to facilitate virus replication. Herein, this review will provide an overview of the role of RHA in the replication of RNA viruses.

The Role of the Representative: Some Empirical Observations on the Theory of Edmund Burke

1959 ◽  
Vol 53 (3) ◽  
pp. 742-756 ◽  
Author(s):  
Heinz Eulau ◽  
John C. Wahlke ◽  
William Buchanan ◽  
Leroy C. Ferguson
Keyword(s):  
Decision Making ◽  
Political Theory ◽  
Empirical Research ◽  
Body Politic ◽  
Whole Body ◽  
Edmund Burke ◽  
Political Systems ◽  
General Consensus ◽  
History Of

The problem of representation is central to all discussions of the functions of legislatures or the behavior of legislators. For it is commonly taken for granted that, in democratic political systems, legislatures are both legitimate and authoritative decision-making institutions, and that it is their representative character which makes them authoritative and legitimate. Through the process of representation, presumably, legislatures are empowered to act for the whole body politic and are legitimized. And because, by virtue of representation, they participate in legislation, the represented accept legislative decisions as authoritative. But agreement about the meaning of the term “representation” hardly goes beyond a general consensus regarding the context within which it is appropriately used. The history of political theory is studded with definitions of representation, usually embedded in ideological assumptions and postulates which cannot serve the uses of empirical research without conceptual clarification.

scholarly journals Interactive effects of aging and aerobic capacity on energy metabolism–related metabolites of serum, skeletal muscle, and white adipose tissue

GeroScience ◽  
2021 ◽  
Author(s):  
Haihui Zhuang ◽  
Sira Karvinen ◽  
Timo Törmäkangas ◽  
Xiaobo Zhang ◽  
Xiaowei Ojanen ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Amino Acid ◽  
White Adipose Tissue ◽  
Aerobic Capacity ◽  
Amino Acid Metabolism ◽  
Acid Metabolism ◽  
Disease Risk ◽  
Whole Body ◽  
Whole Body Metabolism

AbstractAerobic capacity is a strong predictor of longevity. With aging, aerobic capacity decreases concomitantly with changes in whole body metabolism leading to increased disease risk. To address the role of aerobic capacity, aging, and their interaction on metabolism, we utilized rat models selectively bred for low and high intrinsic aerobic capacity (LCRs/HCRs) and compared the metabolomics of serum, muscle, and white adipose tissue (WAT) at two time points: Young rats were sacrificed at 9 months of age, and old rats were sacrificed at 21 months of age. Targeted and semi-quantitative metabolomics analysis was performed on the ultra-pressure liquid chromatography tandem mass spectrometry (UPLC-MS) platform. The effects of aerobic capacity, aging, and their interaction were studied via regression analysis. Our results showed that high aerobic capacity is associated with an accumulation of isovalerylcarnitine in muscle and serum at rest, which is likely due to more efficient leucine catabolism in muscle. With aging, several amino acids were downregulated in muscle, indicating more efficient amino acid metabolism, whereas in WAT less efficient amino acid metabolism and decreased mitochondrial β-oxidation were observed. Our results further revealed that high aerobic capacity and aging interactively affect lipid metabolism in muscle and WAT, possibly combating unfavorable aging-related changes in whole body metabolism. Our results highlight the significant role of WAT metabolism for healthy aging.

scholarly journals Mild DOCA-salt hypertension: sympathetic system and role of renal nerves

2011 ◽  
Vol 300 (5) ◽  
pp. H1781-H1787 ◽  
Author(s):  
Sachin S. Kandlikar ◽  
Gregory D. Fink
Keyword(s):  
Control Period ◽  
Whole Body ◽  
Renal Nerves ◽  
Experimental Hypertension ◽  
Sympathetic Activation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Salt Hypertension ◽  
Hypertension Development

Excess sympathetic nervous system activity (SNA) is linked to human essential and experimental hypertension. To test whether sympathetic activation is associated with a model of deoxycorticosterone acetate (DOCA)-salt hypertension featuring two kidneys and a moderate elevation of blood pressure, we measured whole body norepinephrine (NE) spillover as an index of global SNA. Studies were conducted in chronically catheterized male Sprague-Dawley rats drinking water containing 1% NaCl and 0.2% KCl. After a 7-day surgical recovery and a 3-day control period, a DOCA pellet (50 mg/kg) was implanted subcutaneously in one group of rats (DOCA), while the other group underwent sham implantation (Sham). NE spillover was measured on control day 2 and days 7 and 14 after DOCA administration or sham implantation. During the control period, mean arterial pressure (MAP) was similar in Sham and DOCA rats. MAP was significantly increased in the DOCA group compared with the Sham group after DOCA administration ( day 14: Sham = 109 ± 5.3, DOCA = 128 ± 3.6 mmHg). However, plasma NE concentration, clearance, and spillover were not different in the two groups at any time. To determine whether selective sympathetic activation to the kidneys contributes to hypertension development, additional studies were performed in renal denervated (RDX) and sham-denervated (Sham-DX) rats. MAP, measured by radiotelemetry, was similar in both groups during the control and DOCA treatment periods. In conclusion, global SNA is not increased during the development of mild DOCA-salt hypertension, and fully intact renal nerves are not essential for hypertension development in this model.

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