scholarly journals Mammalian Neuronal mRNA Transport Complexes: The Few Knowns and the Many Unknowns

2021 ◽  
Vol 15 ◽  
Author(s):  
Elsa C. Rodrigues ◽  
Julia Grawenhoff ◽  
Sebastian J. Baumann ◽  
Nicola Lorenzon ◽  
Sebastian P. Maurer
Keyword(s):  
Motor Proteins ◽  
Indirect Evidence ◽  
Transport Processes ◽  
Current Evidence ◽  
Messenger Rnas ◽  
Mrna Transport ◽  
Future Strategy ◽  
The Many ◽  
Local Protein

Hundreds of messenger RNAs (mRNAs) are transported into neurites to provide templates for the assembly of local protein networks. These networks enable a neuron to configure different cellular domains for specialized functions. According to current evidence, mRNAs are mostly transported in rather small packages of one to three copies, rarely containing different transcripts. This opens up fascinating logistic problems: how are hundreds of different mRNA cargoes sorted into distinct packages and how are they coupled to and released from motor proteins to produce the observed mRNA distributions? Are all mRNAs transported by the same transport machinery, or are there different adaptors or motors for different transcripts or classes of mRNAs? A variety of often indirect evidence exists for the involvement of proteins in mRNA localization, but relatively little is known about the essential activities required for the actual transport process. Here, we summarize the different types of available evidence for interactions that connect mammalian mRNAs to motor proteins to highlight at which point further research is needed to uncover critical missing links. We further argue that a combination of discovery approaches reporting direct interactions, in vitro reconstitution, and fast perturbations in cells is an ideal future strategy to unravel essential interactions and specific functions of proteins in mRNA transport processes.

scholarly journals Conditional power of antidepressant network meta-analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Lisa Holper
Keyword(s):  
Meta Analysis ◽  
Indirect Evidence ◽  
Dropout Rate ◽  
Conclusive Evidence ◽  
Effect Sizes ◽  
Current Evidence ◽  
Hamilton Depression Scale ◽  
Conditional Power ◽  
Sample Sizes ◽  
Antidepressant Treatments

Abstract Background Conditional power of network meta-analysis (NMA) can support the planning of randomized controlled trials (RCTs) assessing medical interventions. Conditional power is the probability that updating existing inconclusive evidence in NMA with additional trial(s) will result in conclusive evidence, given assumptions regarding trial design, anticipated effect sizes, or event probabilities. Methods The present work aimed to estimate conditional power for potential future trials on antidepressant treatments. Existing evidence was based on a published network of 502 RCTs conducted between 1979-2018 assessing acute antidepressant treatment in major depressive disorder (MDD). Primary outcomes were efficacy in terms of the symptom change on the Hamilton Depression Scale (HAMD) and tolerability in terms of the dropout rate due to adverse events. The network compares 21 antidepressants consisting of 231 relative treatment comparisons, 164 (efficacy) and 127 (tolerability) of which are currently assumed to have inconclusive evidence. Results Required sample sizes to achieve new conclusive evidence with at least 80% conditional power were estimated to range between N = 894 - 4190 (efficacy) and N = 521 - 1246 (tolerability). Otherwise, sample sizes ranging between N = 49 - 485 (efficacy) and N = 40 - 320 (tolerability) may require stopping for futility based on a boundary at 20% conditional power. Optimizing trial designs by considering multiple trials that contribute both direct and indirect evidence, anticipating alternative effect sizes or alternative event probabilities, may increase conditional power but required sample sizes remain high. Antidepressants having the greatest conditional power associated with smallest required sample sizes were identified as those on which current evidence is low, i.e., clomipramine, levomilnacipran, milnacipran, nefazodone, and vilazodone, with respect to both outcomes. Conclusions The present results suggest that conditional power to achieve new conclusive evidence in ongoing or future trials on antidepressant treatments is low. Limiting the use of the presented conditional power analysis are primarily due to the estimated large sample sizes which would be required in future trials as well as due to the well-known small effect sizes in antidepressant treatments. These findings may inform researchers and decision-makers regarding the clinical relevance and justification of research in ongoing or future antidepressant RCTs in MDD.

scholarly journals Substrate Stiffness and Stretch Regulate Profibrotic Mechanosignaling in Pulmonary Arterial Adventitial Fibroblasts

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1000
Author(s):  
Ariel Wang ◽  
Shulin Cao ◽  
Jennifer C. Stowe ◽  
Daniela Valdez-Jasso
Keyword(s):  
Transforming Growth Factor ◽  
Substrate Stiffness ◽  
Messenger Rnas ◽  
Ang Ii ◽  
Integrin Β3 ◽  
Custom Made ◽  
Adventitial Fibroblasts ◽  
Pulmonary Arterial ◽  
Six Genes

Pulmonary arterial adventitial fibroblasts (PAAFs) are important regulators of fibrotic vascular remodeling during the progression of pulmonary arterial hypertension (PAH), a disease that currently has no effective anti-fibrotic treatments. We conducted in-vitro experiments in PAAFs cultured on hydrogels attached to custom-made equibiaxial stretchers at 10% stretch and substrate stiffnesses representing the mechanical conditions of mild and severe stages of PAH. The expression of collagens α(1)I and α(1)III and elastin messenger RNAs (Col1a1, Col3a1, Eln) were upregulated by increased stretch and substrate stiffness, while lysyl oxidase-like 1 and α-smooth muscle actin messenger RNAs (Loxl1, Acta2) were only significantly upregulated when the cells were grown on matrices with an elevated stiffness representative of mild PAH but not on a stiffness representative of severe PAH. Fibronectin messenger RNA (Fn1) levels were significantly induced by increased substrate stiffness and transiently upregulated by stretch at 4 h, but was not significantly altered by stretch at 24 h. We modified our published computational network model of the signaling pathways that regulate profibrotic gene expression in PAAFs to allow for differential regulation of mechanically-sensitive nodes by stretch and stiffness. When the model was modified so that stiffness activated integrin β3, the Macrophage Stimulating 1 or 2 (MST1\2) kinases, angiotensin II (Ang II), transforming growth factor-β (TGF-β), and syndecan-4, and stretch-regulated integrin β3, MST1\2, Ang II, and the transient receptor potential (TRP) channel, the model correctly predicted the upregulation of all six genes by increased stiffness and the observed responses to stretch in five out of six genes, although it could not replicate the non-monotonic effects of stiffness on Loxl1 and Acta2 expression. Blocking Ang II Receptor Type 1 (AT1R) with losartan in-vitro uncovered an interaction between the effects of stretch and stiffness and angiotensin-independent activation of Fn1 expression by stretch in PAAFs grown on 3-kPa matrices. This novel combination of in-vitro and in-silico models of PAAF profibrotic cell signaling in response to altered mechanical conditions may help identify regulators of vascular adventitial remodeling due to changes in stretch and matrix stiffness that occur during the progression of PAH in-vivo.

scholarly journals Prion Diseases: A Unique Transmissible Agent or a Model for Neurodegenerative Diseases?

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 207
Author(s):  
Diane L. Ritchie ◽  
Marcelo A. Barria
Keyword(s):  
Public Health ◽  
Neurodegenerative Diseases ◽  
Prion Protein ◽  
Neurodegenerative Disorders ◽  
Prion Diseases ◽  
Experimental Models ◽  
Misfolded Proteins ◽  
Current Evidence

The accumulation and propagation in the brain of misfolded proteins is a pathological hallmark shared by many neurodegenerative diseases such as Alzheimer’s disease (Aβ and tau), Parkinson’s disease (α-synuclein), and prion disease (prion protein). Currently, there is no epidemiological evidence to suggest that neurodegenerative disorders are infectious, apart from prion diseases. However, there is an increasing body of evidence from experimental models to suggest that other pathogenic proteins such as Aβ and tau can propagate in vivo and in vitro in a prion-like mechanism, inducing the formation of misfolded protein aggregates such as amyloid plaques and neurofibrillary tangles. Such similarities have raised concerns that misfolded proteins, other than the prion protein, could potentially transmit from person-to-person as rare events after lengthy incubation periods. Such concerns have been heightened following a number of recent reports of the possible inadvertent transmission of Aβ pathology via medical and surgical procedures. This review will provide a historical perspective on the unique transmissible nature of prion diseases, examining their impact on public health and the ongoing concerns raised by this rare group of disorders. Additionally, this review will provide an insight into current evidence supporting the potential transmissibility of other pathogenic proteins associated with more common neurodegenerative disorders and the potential implications for public health.

scholarly journals Expression of Hyaluronan Synthases and CD44 Messenger RNAs in Porcine Cumulus-Oocyte Complexes During In Vitro Maturation1

2002 ◽  
Vol 66 (3) ◽  
pp. 707-717 ◽  
Author(s):  
Naoko Kimura ◽  
Yoshiaki Konno ◽  
Kazuchika Miyoshi ◽  
Hiromichi Matsumoto ◽  
Eimei Sato
Keyword(s):  
Messenger Rnas ◽  
Hyaluronan Synthases

scholarly journals Tobacco Mosaic Virus Movement Protein Functions as a Structural Microtubule-Associated Protein

2006 ◽  
Vol 80 (17) ◽  
pp. 8329-8344 ◽  
Author(s):  
Jamie Ashby ◽  
Emmanuel Boutant ◽  
Mark Seemanpillai ◽  
Adrian Sambade ◽  
Christophe Ritzenthaler ◽  
...  
Keyword(s):  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Movement Protein ◽  
Cell Extract ◽  
Transport Processes ◽  
In Vitro Assays ◽  
Protein Functions ◽  
Intercellular Spread

ABSTRACT The cell-to-cell spread of Tobacco mosaic virus infection depends on virus-encoded movement protein (MP), which is believed to form a ribonucleoprotein complex with viral RNA (vRNA) and to participate in the intercellular spread of infectious particles through plasmodesmata. Previous studies in our laboratory have provided evidence that the vRNA movement process is correlated with the ability of the MP to interact with microtubules, although the exact role of this interaction during infection is not known. Here, we have used a variety of in vivo and in vitro assays to determine that the MP functions as a genuine microtubule-associated protein that binds microtubules directly and modulates microtubule stability. We demonstrate that, unlike MP in whole-cell extract, microtubule-associated MP is not ubiquitinated, which strongly argues against the hypothesis that microtubules target the MP for degradation. In addition, we found that MP interferes with kinesin motor activity in vitro, suggesting that microtubule-associated MP may interfere with kinesin-driven transport processes during infection.

scholarly journals Muscle-specific microRNA miR-206 promotes muscle differentiation

2006 ◽  
Vol 174 (5) ◽  
pp. 677-687 ◽  
Author(s):  
Hak Kyun Kim ◽  
Yong Sun Lee ◽  
Umasundari Sivaprasad ◽  
Ankit Malhotra ◽  
Anindya Dutta
Keyword(s):  
Antisense Oligonucleotide ◽  
Small Interfering Rna ◽  
Degradation Process ◽  
Microrna Target ◽  
C2c12 Myoblasts ◽  
Target Sites ◽  
The Many ◽  
Interfering Rna ◽  
In Vitro Transfection

Three muscle-specific microRNAs, miR-206, -1, and -133, are induced during differentiation of C2C12 myoblasts in vitro. Transfection of miR-206 promotes differentiation despite the presence of serum, whereas inhibition of the microRNA by antisense oligonucleotide inhibits cell cycle withdrawal and differentiation, which are normally induced by serum deprivation. Among the many mRNAs that are down-regulated by miR-206, the p180 subunit of DNA polymerase α and three other genes are shown to be direct targets. Down-regulation of the polymerase inhibits DNA synthesis, an important component of the differentiation program. The direct targets are decreased by mRNA cleavage that is dependent on predicted microRNA target sites. Unlike small interfering RNA–directed cleavage, however, the 5′ ends of the cleavage fragments are distributed and not confined to the target sites, suggesting involvement of exonucleases in the degradation process. In addition, inhibitors of myogenic transcription factors, Id1-3 and MyoR, are decreased upon miR-206 introduction, suggesting the presence of additional mechanisms by which microRNAs enforce the differentiation program.

scholarly journals Observations on the Growth of Meningococciin vitroin Relation to Virulence: A Report to the Medical Research Council on Work Carried out at the University of Cambridge pathological laboratory and field Laboratories

1924 ◽  
Vol 23 (1) ◽  
pp. 23-63 ◽  
Author(s):  
E. G. D. Murray ◽  
R. Ayrton
Keyword(s):  
Medical Research ◽  
Research Council ◽  
Medical Research Council ◽  
Culture Media ◽  
University Of Cambridge ◽  
The Many ◽  
The University ◽  
Growth Of Bacteria

Every bacteriologist is only too well aware of the many problems presented by the preparation of culture media for the growth of bacteriain vitro.

scholarly journals Food and Food Groups in Inflammatory Bowel Disease (IBD): The Design of the Groningen Anti-Inflammatory Diet (GrAID)

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1067
Author(s):  
Marjo J. E. Campmans-Kuijpers ◽  
Gerard Dijkstra
Keyword(s):  
Inflammatory Bowel Disease ◽  
Bowel Disease ◽  
Food Group ◽  
Dietary Guidelines ◽  
Current Evidence ◽  
Group Level ◽  
Food Groups ◽  
Inflammatory Bowel ◽  
Anti Inflammatory

Diet plays a pivotal role in the onset and course of inflammatory bowel disease (IBD). Patients are keen to know what to eat to reduce symptoms and flares, but dietary guidelines are lacking. To advice patients, an overview of the current evidence on food (group) level is needed. This narrative review studies the effects of food (groups) on the onset and course of IBD and if not available the effects in healthy subjects or animal and in vitro IBD models. Based on this evidence the Groningen anti-inflammatory diet (GrAID) was designed and compared on food (group) level to other existing IBD diets. Although on several foods conflicting results were found, this review provides patients a good overview. Based on this evidence, the GrAID consists of lean meat, eggs, fish, plain dairy (such as milk, yoghurt, kefir and hard cheeses), fruit, vegetables, legumes, wheat, coffee, tea and honey. Red meat, other dairy products and sugar should be limited. Canned and processed foods, alcohol and sweetened beverages should be avoided. This comprehensive review focuses on anti-inflammatory properties of foods providing IBD patients with the best evidence on which foods they should eat or avoid to reduce flares. This was used to design the GrAID.

The location and mechanism of hyperosmotic fluid secretion in the rectum of the saline-water mosquito larvae Aedes taeniorhynchus

1977 ◽  
Vol 66 (1) ◽  
pp. 111-126
Author(s):  
T. J. Bradley ◽  
J. E. Phillips
Keyword(s):  
Saline Water ◽  
Fluid Secretion ◽  
Opposite Polarity ◽  
Posterior Segment ◽  
Transport Processes ◽  
Cell Border ◽  
Experimental Conditions ◽  
Ultrastructural Studies ◽  
Aedes Taeniorhynchus

1. Ligation between the anterior and posterior segments of the rectum in vitro was used to demonstrate that the posterior rectum is the site of hyperosmotic secretion to the lumen side. Observations were consistent with a reabsorptive function for the anterior rectum. These results support predictions from ultrastructural studies of these two segments. 2. The initial potential of the rectal lumen, relative to the haemocoel side, was of opposite polarity in the anterior (−10 mV) and posterior (+ 10 mV) segments and these values decreased to −2 and +6 mV respectively in ligated recta which had secreted for 2 h. 3. A comparison of these potential difference measurements with concentration differences developed across the rectal epithelium under the same experimental conditions indicates that Na+, K+, Mg2+, and Cl- are all actively transported by the posterior segment to the lumen side. 4. The influence of different haemolymph concentrations of Na+, K+, and Cl- on the potential differences across the basal cell border and across the whole rectal epithelium are reported. Based on this and previous data, we propose a model for the organization of transport processes within the single celltype present in the posterior rectal epithelium.

Direct effect of parathyroid hormone on insulin secretion from pancreatic islets

1990 ◽  
Vol 258 (6) ◽  
pp. E975-E984 ◽  
Author(s):  
G. Z. Fadda ◽  
M. Akmal ◽  
L. G. Lipson ◽  
S. G. Massry
Keyword(s):  
Insulin Secretion ◽  
Parathyroid Hormone ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Direct Effect ◽  
Indirect Evidence ◽  
Cytosolic Calcium ◽  
Dependent Manner ◽  
Stimulation Of

Indirect evidence indicates that parathyroid hormone (PTH) interacts with pancreatic islets and modulates their insulin secretion. This property of PTH has been implicated in the genesis of impaired insulin release in chronic renal failure. We examined the direct effect of PTH-(1-84) and PTH-(1-34) on insulin release using in vitro static incubation and dynamic perifusion of pancreatic islets from normal rats. Both moieties of the hormone stimulated in a dose-dependent manner glucose-induced insulin release but higher doses inhibited glucose-induced insulin release. This action of PTH was modulated by the calcium concentration in the media. The stimulatory effect of PTH was abolished by its inactivation and blocked by its antagonist [Tyr-34]bPTH-(7-34)NH2. PTH also augmented phorbol ester (TPA)-induced insulin release, stimulated adenosine 3',5'-cyclic monophosphate (cAMP) generation by pancreatic islets, and significantly increased (+50 +/- 2.7%, P less than 0.01) their cytosolic calcium. Verapamil inhibited the stimulatory effect of PTH on insulin release. The data show that 1) pancreatic islets are a PTH target and may have PTH receptors, 2) stimulation of glucose-induced insulin release by PTH is mediated by a rise in cytosolic calcium, 3) stimulation of cAMP production by PTH and a potential indirect activation of protein kinase C by PTH may also contribute to the stimulatory effect on glucose-induced insulin release, and 4) this action of PTH requires calcium in incubation or perifusion media.

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