scholarly journals Glial Cell Responses to constant low Light exposure in Rat Retina.

2021 ◽  
Author(s):  
Manuel Gaston Bruera ◽  
Maria Mercedes Benedetto ◽  
Mario Eduardo Guido ◽  
Alicia Laura Degano ◽  
Maria Ana Contin
Keyword(s):  
Glial Cells ◽  
Time Course ◽  
Light Exposure ◽  
Outer Nuclear Layer ◽  
Constant Light ◽  
Early Event ◽  
Mrna Levels ◽  
Low Light ◽  
Expression Levels ◽  
Low Intensity

Retinal damage promoted by constant illumination of low intensity resulted in a diminution in classical photoreceptors cells. Glial cells exert profound effects on neurons, vasculature and other glial cells. Macroglia and microglia with specific morphological, physiological, and antigenic characteristics may play an essential role in both the maintenance and control of retinal homeostasis, or to exert mechanisms that promote cell death. The role of glial cells and immune function in the pathogenesis promoted by low light is poorly understood. We performed glial cells characterization along the time-course of retinal degeneration induced by chronic exposure to low intensity of light in Wistar rats. We exposed the animals at constant light from 2 to 8 days and assessed the retinal glia. After 6 days of light exposure, retinas presented increased levels of GFAP, a macroglia marker and microglia markers Iba1 and CD68 displayed increased mRNA levels after 6 days. The number of Iba1 positive cells increased in the outer nuclear layer, showing ameboid morphology with thicker processes characteristic of microglial activated cells. The expression levels of immune mediators TNF-𝜶 and IL-6 were also significantly increased after 6 days. Finally, chemokines analysis showed that CX3CR1 and CCL2 expression levels were significantly elevated after 6 days. Hence, all the events of glial activation occurred after 5-6 days of constant light exposure, when the number of cells of the outer nuclear layer has already decreased significantly. Herein we demonstrated that glial and immune activation are secondary to neurodegeneration; in this scenario, our results suggest that photoreceptor death is an early event that may be induced by phototransduction-dependent mechanisms.

scholarly journals The Role of Interleukin-6 (IL-6) in Human Sulfur Mustard (HD) Toxicology

2001 ◽  
Vol 20 (5) ◽  
pp. 281-296 ◽  
Author(s):  
Carmen M. Arroyo ◽  
Clarence A. Broomfield ◽  
Brennie E. Hackley
Keyword(s):  
Interleukin 6 ◽  
Time Course ◽  
Structural Changes ◽  
Sulfur Mustard ◽  
Skin Irritation ◽  
Epidermal Keratinocytes ◽  
Early Event ◽  
Mrna Levels ◽  
Human Epidermal Keratinocytes

The authors applied in vitro models of controlled damage to human epidermal keratinocytes (HEKs), human skin fibroblasts (HSFs), and human breast skin tissue (HBST) to examine the mechanism responsible for sulfur mustard (HD)-induced interleukin-6 (IL-6) alterations. Treatment with 100 μM HD for 24 hours resulted in a significant increased amount of IL-6 being secreted by HEKs (HD-exposed to control ratio [E/C] = 4.15 ± 0.07) and by HSFs (E/C = 7.66 ± 0.04). Furthermore, the HD-induced secretion of IL-6 in HEKs was neutralized with monoclonal human IL-6 antibodies. The secretion of IL-6 in HBST supernatant exposed to HD produced conflicting results. Although an increase of IL-6 was observed in control superfusion media from HBST, IL-6 levels were observed to decrease as the concentration of HD increased. Time course of IL-6 mRNA levels were performed using a competitive polymerase chain reaction (PCR) and human IL-6 mRNA assay detection kit in control and HD (100 μM)-treated HEKs cells. IL-6 mRNA transcripts in HD-exposed HEKs were first observed within 2 hours, dropped at 5 to 6 hours, and increased by ® 2.2-fold and 8.5-fold at 24 to 48 hours after HD exposure, respectively, as detected by the Xplore mRNA Quantification System. Surface-enhanced laser desorption ionization (SELDI) mass spectrometry was also applied to study the secretion pattern of IL-6 on lysate preparations of HBST. A peak in the area of 23,194 to 23,226 Da was detected using antibody coupled to the chip. This peak was assigned to correspond to the mass of the IL-6 glycoprotein. Recombinant human IL-6 (rhIL-6) exposed to HD lacked the second disulfide bridge and was partially unfolded, as determined by nuclear magnetic resonance-nuclear Overhauser enhancement and exchange spectroscopy (NMR-NOESY). The disappearance of the resonance peak at 3.54 ppm and the appearance of a new chemical shift at 1.85 ppm suggested that a change in structure had occurred in the presence of HD. From the data, the possibility cannot be excluded that IL-6 might be involved in the early event of structural changes of the signal transducer glycoprotein that indirectly initiates the cascade of events such as skin irritation and blister formation observed in the pathophysiology of HD injury.

scholarly journals Photoperiodically driven transcriptome-wide changes in the hypothalamus reveal transcriptional differences between physiologically contrasting seasonal life-history states in migratory songbirds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aakansha Sharma ◽  
Subhajit Das ◽  
Sayantan Sur ◽  
Jyoti Tiwari ◽  
Khushboo Chaturvedi ◽  
...  
Keyword(s):  
Life History ◽  
Time Course ◽  
Light Exposure ◽  
Degradation Pathway ◽  
Apolipoprotein A1 ◽  
Mrna Levels ◽  
Rna Seq ◽  
Transcriptional Responses ◽  
Migratory Songbirds ◽  
Short Days

AbstractWe investigated time course of photoperiodically driven transcriptional responses in physiologically contrasting seasonal life-history states in migratory blackheaded buntings. Birds exhibiting unstimulated winter phenotype (photosensitive state; responsive to photostimulation) under 6-h short days, and regressed summer phenotype (photorefractory state; unresponsiveness to photostimulation) under 16-h long days, were released into an extended light period up to 22 h of the day. Increased tshβ and dio2, and decreased dio3 mRNA levels in hypothalamus, and low prdx4 and high il1β mRNA levels in blood confirmed photoperiodic induction by hour 18 in photosensitive birds. Further, at hours 10, 14, 18 and 22 of light exposure, the comparison of hypothalamus RNA-Seq results revealed transcriptional differences within and between states. Particularly, we found reduced expression at hour 14 of transthyretin and proopiomelanocortin receptor, and increased expression at hour 18 of apolipoprotein A1 and carbon metabolism related genes in the photosensitive state. Similarly, valine, leucine and isoleucine degradation pathway genes and superoxide dismutase 1 were upregulated, and cocaine- and amphetamine-regulated transcript and gastrin-releasing peptide were downregulated in the photosensitive state. These results show life-history-dependent activation of hypothalamic molecular pathways involved in initiation and maintenance of key biological processes as early as on the first long day.

Abstract TP346: Pge2 Ep1-4 Temporospatial Expression Level Changes in the Brain After Intracerebral Hemorrhage in Young, Aged, and Ep1 Deficient Mice Suggests Cross-talk Interactions

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Jenna L Leclerc ◽  
Andrew R Fadool ◽  
Julie C Bailes ◽  
Chase Chambers ◽  
Sylvain Doré
Keyword(s):  
Intracerebral Hemorrhage ◽  
Cross Talk ◽  
Time Course ◽  
Expression Profiles ◽  
Receptor Expression ◽  
Prostaglandin E ◽  
Mrna Levels ◽  
Expression Levels ◽  
Ep Receptors ◽  
Ep Receptor

Intracerebral hemorrhage (ICH) is the most severe form of stroke with the highest mortality. Neuroinflammation contributes to ICH-induced brain injury and the upregulation of prostaglandin E 2 (PGE 2 ) has been implicated in modulating these deleterious pathways. PGE 2 acts mainly on four G-protein-coupled E Prostanoid (EP) receptors, EP1-4, each having different downstream pathways, tissue distributions, and expression profiles. Our previous studies demonstrate that EP1 receptor deletion promotes injury following ICH; whereas, deletion of EP2 and EP3 is neuroprotective in an equivalent approach. Here, we aimed to investigate the time course, brain sub-region expression profile, and relative level of EP1-4 mRNA expression in young (5-7mo) and aged (12-13mo) wildtype (WT) and EP1-/- mice. Following ICH or sham surgery, EP1-4 mRNA levels were assessed by RT-qPCR whereby the relative fold change of the gene of interest were determined using the reference gene Tbp and the 2 -ΔΔCT method relative to the control. Minimal EP1-4 expression changes are seen at 24h after ICH; although, EP2 (p=0.036) and EP4 (p=0.066) are 1.6X increased in the cortex of young WT mice. At 72h post-ICH, EP1 is 3.9x elevated in the cortex (p=0.0003) and 4.6x in the striatum (p=0.012). EP3 is also 1.6x elevated in the cortex (p=0.044). In the contralateral hemisphere, a mean 2.4x increase of EP1-4 (p<0.01) expression is seen. In contrast, at 72h after ICH, EP1-/- mice have 0.53x reduced EP3 in the cortex (p=0.030) and 0.68x and 0.71x decreased EP3 (p=0.016) and EP4 (p=0.049), respectively, in the contralateral. Aged EP1 -/- mice show significantly decreased expression levels of EP2-4 in nearly all areas. Due to the contralateral differences, basal expression levels of EP2-4 were investigated in the EP1-/- mice, where EP2 is 2.6x, 3.4x, and 3.8x increased in the cortex, hippocampus, and cerebellum; whereas, EP3 trended oppositely. These data indicate a cross talk between EP1 and the other EP receptors pre- and post-ICH and an association between age and EP receptor expression levels. A better understanding of EP receptor localization and dynamic expression levels after ICH will spark the development of effective pharmacological treatments. Funding: NIH F31NS086441 (JLL) and R01NS046400 (SD)

Constant light exposure impairs immune tolerance development in mice

2017 ◽  
Vol 86 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Hiromi Mizutani ◽  
Risa Tamagawa-Mineoka ◽  
Yoichi Minami ◽  
Kazuhiro Yagita ◽  
Norito Katoh
Keyword(s):  
Immune Tolerance ◽  
Light Exposure ◽  
Constant Light ◽  
Tolerance Development

scholarly journals Methylobacterium oryzae Influences Isoepoxydon Dehydrogenase Gene Expression and Patulin Production by Penicillium expansum

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1427
Author(s):  
Tiago Barros Afonso ◽  
Lúcia Chaves Simões ◽  
Nelson Lima
Keyword(s):  
Gene Expression ◽  
Distribution Systems ◽  
Water Distribution ◽  
Penicillium Expansum ◽  
Transcriptional Level ◽  
Positive Trend ◽  
Mrna Levels ◽  
Expression Levels ◽  
Production Values ◽  
Methylobacterium Oryzae

Biofilms can be considered the main source of microorganisms in drinking water distribution systems (DWDS). The ecology of a biofilm is dependent on a variety of factors, including the presence of microbial metabolites excreted by its inhabitants. This study reports the effect of the Gram-negative bacteria Methylobacterium oryzae on the idh gene expression levels and patulin production of Penicillium expansum mature biofilms. For this purpose, a RT-qPCR method to quantify idh mRNA levels was applied. In addition, the idh expression levels were compared with the patulin production. The results obtained revealed that the effect of the bacterium on pre-established P. expansum biofilms is dependent on the time of interaction. More mature P. expansum biofilms appear to be more resistant to the inhibitory effect that M. oryzae causes towards idh gene expression and patulin production. A positive trend was observed between the idh expression and patulin production values. The results indicate that M. oryzae affects patulin production by acting at the transcriptional level of the idh gene.

scholarly journals Compensation Mechanism of the Photosynthetic Apparatus in Arabidopsis thaliana ch1 Mutants

2020 ◽  
Vol 22 (1) ◽  
pp. 221
Author(s):  
Joanna Wójtowicz ◽  
Adam K. Jagielski ◽  
Agnieszka Mostowska ◽  
Katarzyna B. Gieczewska
Keyword(s):  
Light Stress ◽  
Photosynthetic Apparatus ◽  
Protein Composition ◽  
Mrna Levels ◽  
Chlorophyll B ◽  
Low Light ◽  
Plant Acclimation ◽  
Chlorophyll B Deficiency ◽  
Composition Changes

The origin of chlorophyll b deficiency is a mutation (ch1) in chlorophyllide a oxygenase (CAO), the enzyme responsible for Chl b synthesis. Regulation of Chl b synthesis is essential for understanding the mechanism of plant acclimation to various conditions. Therefore, the main aim of this study was to find the strategy in plants for compensation of low chlorophyll content by characterizing and comparing the performance and spectral properties of the photosynthetic apparatus related to the lipid and protein composition in four selected Arabidopsis ch1 mutants and two Arabidopsis ecotypes. Mutation in different loci of the CAO gene, viz., NW41, ch1.1, ch1.2 and ch1.3, manifested itself in a distinct chlorina phenotype, pigment and photosynthetic protein composition. Changes in the CAO mRNA levels and chlorophyllide a (Chlide a) content in ecotypes and ch1 mutants indicated their significant role in the adjustment mechanism of the photosynthetic apparatus to low-light conditions. Exposure of mutants with a lower chlorophyll b content to short-term (1LL) and long-term low-light stress (10LL) enabled showing a shift in the structure of the PSI and PSII complexes via spectral analysis and the thylakoid composition studies. We demonstrated that both ecotypes, Col-1 and Ler-0, reacted to high-light (HL) conditions in a way remarkably resembling the response of ch1 mutants to normal (NL) conditions. We also presented possible ways of regulating the conversion of chlorophyll a to b depending on the type of light stress conditions.

A laboratory study of vertical migration

1955 ◽  
Vol 144 (916) ◽  
pp. 329-354 ◽  
Keyword(s):  
Light Intensity ◽  
Vertical Migration ◽  
Time Course ◽  
Tap Water ◽  
Low Light ◽  
Overhead Light ◽  
Light Intensities ◽  
Orientation Response ◽  
Reduced Light ◽  
Characteristic Maximum

In a tank filled with a suspension of indian ink in tap water, a population of Daphnia magna will undergo a complete cycle of vertical migration when an overhead light source is cycli­cally varied in intensity. A ‘dawn rise’ to the surface at low intensity is followed by the descent of the animals to a characteristic maximum depth. The animals rise to the surface again as the light decreases, and finally show a typical midnight sinking. The light intensities at the level of the animals in this experiment are of the same order as those which have been reported in field observations; the time course of the movement also repeats the natural conditions in the field. The process is independent of the duration of the cycle and is related only to the variation in overhead light intensity. At low light intensity the movement of the animal is determined solely by positive photo-kinesis; the dawn rise is a manifestation of this, and is independent of the direction of the light. At high light intensities there is an orientation response which is superimposed upon an alternating positive (photokinetic) phase and a negative phase during which movement is inhibited. The fully oriented animal shows a special type of positive and negative phototaxis, moving towards the light at reduced light intensities and away from it when the light intensity is increased. In this condition it follows a zone of optimum light intensity with some exactness. Experiments show that an animal in this fully oriented condition will respond to the slow changes of intensity characteristic of the diurnal cycle, while being little affected by tran­sient changes of considerable magnitude.

Dynamic changes in conduction velocity and gap junction properties during development of pacing-induced heart failure

2007 ◽  
Vol 293 (2) ◽  
pp. H1223-H1230 ◽  
Author(s):  
Fadi G. Akar ◽  
Robert D. Nass ◽  
Samuel Hahn ◽  
Eugenio Cingolani ◽  
Manish Shah ◽  
...  
Keyword(s):  
Heart Failure ◽  
Conduction Velocity ◽  
Connexin 43 ◽  
Time Course ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Early Event ◽  
Mechanical Function ◽  
Dynamic Changes ◽  
End Stage

End-stage heart failure (HF) is characterized by changes in conduction velocity (CV) that predispose to arrhythmias. Here, we investigate the time course of conduction changes with respect to alterations in connexin 43 (Cx43) properties and mechanical function during the development of HF. We perform high-resolution optical mapping in arterially perfused myocardial preparations from dogs subjected to 0, 3, 7, 14, and 21 days of rapid pacing to produce variable degrees of remodeling. CV is compared with an index of mechanical function [left ventricular end-diastolic pressure (LVEDP)] and with dynamic changes in the expression, distribution, and phosphorylation of Cx43. In contrast to repolarization, CV was preserved during early stages of remodeling (3 and 7 days) and significantly reduced at later stages, which were associated with marked increases in LVEDP. Measurements of differentially phosphorylated Cx43 isoforms revealed early, sustained downregulation of pan-Cx43 that preceded changes in CV and LVEDP, a gradual rise in a dephosphorylated Cx43 isoform to over twofold baseline levels in end-stage HF, and a late abrupt increase in pan-Cx43, but not dephosphorylated Cx43, lateralization. These data demonstrate that 1) CV slowing occurs only at advanced stages of remodeling, 2) total reduction of pan-Cx43 is an early event that precedes mechanical dysfunction and CV slowing, 3) changes in Cx43 phosphorylation are more closely associated with the onset of HF, and 4) Cx43 lateralization is a late event that coincides with marked CV reduction. These data reveal a novel paradigm of remodeling based on the timing of conduction abnormalities relative to changes in Cx43 isoforms and mechanical dysfunction.

scholarly journals Gene Expression of Nucleic Acid-Sensing Pattern Recognition Receptors in Children Hospitalized for Respiratory Syncytial Virus-Associated Acute Bronchiolitis

2009 ◽  
Vol 16 (6) ◽  
pp. 816-823 ◽  
Author(s):  
Carolina Scagnolari ◽  
Fabio Midulla ◽  
Alessandra Pierangeli ◽  
Corrado Moretti ◽  
Enea Bonci ◽  
...  
Keyword(s):  
Gene Expression ◽  
Pattern Recognition ◽  
Viral Load ◽  
Respiratory Syncytial Virus ◽  
Pattern Recognition Receptors ◽  
Mrna Levels ◽  
Acute Bronchiolitis ◽  
Expression Levels ◽  
Rsv Infection ◽  
Syncytial Virus

ABSTRACT Given the critical role of pattern recognition receptors (PRRs) in acid nucleic recognition in the initiation of innate immunity and the orchestration of adaptive immunity, the aim of this study was to determine whether any heterogeneity of PRR expression in the airway tracts of infants with respiratory syncytial virus (RSV) infection might explain the broad clinical spectrum of RSV-associated bronchiolitis in infants. For this purpose, the levels of melanoma differentiation-associated protein-5 (MDA-5), retinoic acid inducible gene-1 (RIG-1), and Toll-like receptor 3 (TLR-3), TLR-7, TLR-8, and TLR-9 mRNAs were evaluated, using TaqMan quantitative reverse transcription-PCR, in cells from nasopharyngeal washes collected from 157 infants suffering from acute bronchiolitis whether or not they were associated with respiratory viruses. High interindividual variability was observed in both virus-positive and -negative infants; however, the relative gene expression levels of MDA-5, RIG-1, TLR-7, and TLR-8 were significantly higher in the virus-infected group, whereas the expression levels of TLR-3 and TLR-9 were not significantly different. The differences in the gene expression of MDA-5, RIG-1, TLR-7, and TLR-8 were more evident in infants with RSV infection than in those with bocavirus or rhinovirus infection. In RSV-infected infants, PRR-mRNA levels also were analyzed in relation to interferon protein levels, viral load, clinical severity, days of hospitalization, age, and body weight. A significant positive correlation was observed only between RSV viral load and RIG-1 mRNA levels. These findings provide the first direct evidence that, in infants with respiratory virus-associated bronchiolitis, especially RSV, there are substantial changes in PRR gene expression; this likely is an important determinant of the clinical outcome of bronchiolitis.

Sign in / Sign up

Export Citation Format

Share Document