scholarly journals Blue light induces neuronal-activity-regulated gene expression in the absence of optogenetic proteins

2019 ◽  
Author(s):  
Kelsey M. Tyssowski ◽  
Jesse M. Gray
Keyword(s):  
Blue Light ◽  
Neuronal Activity ◽  
Cortical Neurons ◽  
Light Exposure ◽  
Green Light ◽  
Neuronal Firing ◽  
Light Stimulation ◽  
Cellular Functions ◽  
Regulated Gene Expression ◽  
Optogenetic Control

Optogenetics is widely used to control diverse cellular functions with light, requiring experimenters to expose cells to bright light. Because extended exposure to visible light can be toxic to cells, it is important to characterize the effects of light stimulation on cellular function in the absence of exogenous optogenetic proteins. Here we exposed cultured mouse cortical neurons that did not express optogenetic proteins to several hours of flashing blue, red, or green light. We found that exposing neurons to as short as one hour of blue, but not red or green, light results in the induction of neuronal-activity-regulated genes without inducing neuronal activity. Our findings suggest blue light stimulation is ill-suited to long-term optogenetic experiments, especially those that measure transcription.Significance StatementOptogenetics is widely used to control cellular functions using light. In neuroscience, channelrhodopsins, exogenous light-sensitive channels, are used to achieve light-dependent control of neuronal firing. This optogenetic control of neuronal firing requires exposing neurons to high-powered light. We ask how this light exposure, in the absence of channelrhodopsin, affects the expression of neuronal-activity-regulated genes, i.e., the genes that are transcribed in response to neuronal stimuli. Surprisingly, we find that neurons without channelrhodopsin express neuronal-activity-regulated genes in response to as short as an hour of blue, but not red or green, light exposure. These findings suggest that experimenters wishing to achieve longer-term (an hour or more) optogenetic control over neuronal firing should avoid using systems that require blue light.

scholarly journals Blue light-induced gene expression alterations in cultured neurons are the result of phototoxic interactions with neuronal culture media

2019 ◽  
Author(s):  
Corey G. Duke ◽  
Katherine E. Savell ◽  
Robert A. Phillips ◽  
Jeremy J. Day
Keyword(s):  
Gene Expression ◽  
Blue Light ◽  
Cortical Neurons ◽  
Clock Genes ◽  
Culture Media ◽  
Light Exposure ◽  
Neuronal Culture ◽  
Gene Expression Alterations

Blue waveform light is used as an optical actuator in numerous optogenetic technologies employed in neuronal systems. However, the potential side effects of blue waveform light in neurons has not been thoroughly explored, and recent reports suggest that neuronal exposure to blue light can induce transcriptional alterations in vitro and in vivo. Here, we examined the effects of blue waveform light in cultured primary rat cortical neurons. Exposure to blue light (470nm) resulted in upregulation of several immediate early genes (IEGs) traditionally used as markers of neuronal activity, including Fos and Fosb, but did not alter the expression of circadian clock genes Bmal1, Cry1, Cry2, Clock, or Per2. IEG expression was increased following 4 hours of 5% duty cycle light exposure, and IEG induction was not dependent on light pulse width. Elevated levels of blue light exposure induced a loss of cell viability in vitro, suggestive of overt phototoxicity. Changes in gene expression induced by blue waveform light were prevented when neurons were cultured in a photoinert media supplemented with a photostable neuronal supplement instead of commonly utilized neuronal culture media and supplements. Together, these findings suggest that light-induced gene expression alterations observed in vitro stem from a phototoxic interaction between commonly used media and neurons, and offer a solution to prevent this toxicity when using photoactivatable technology in vitro.

scholarly journals Light-Dependent Effects of Prefrontal rTMS on Emotional Working Memory

2021 ◽  
Vol 11 (4) ◽  
pp. 446
Author(s):  
Anne Weigand ◽  
Lisa Edelkraut ◽  
Markus Conrad ◽  
Simone Grimm ◽  
Malek Bajbouj
Keyword(s):  
Working Memory ◽  
Blue Light ◽  
Brain Stimulation ◽  
Light Exposure ◽  
Green Light ◽  
State Dependency ◽  
Brain Functions ◽  
Non Invasive ◽  
Resting Motor Threshold ◽  
The Impact

Growing evidence suggests that colored light exposure can affect several brain functions in addition to conscious visual perception. Blue as compared to green light has especially been shown to enhance alertness and vigilance, as well as cognitive functions. However, the role of light exposure in studies using non-invasive brain stimulation remains unclear. Here, we examined the impact of light on cognitive-emotional effects of prefrontal repetitive transcranial magnetic stimulation (rTMS). In a randomized within-subjects design, twenty participants (12 males, 26 ± 4 years) were exposed to blue or green light prior and concomitant to active or sham rTMS (1Hz, 15min, 110% of the resting motor threshold), applied over the right dorsolateral prefrontal cortex (DLPFC). In each condition, an emotional working memory task (EMOBACK) was presented pre- and post-intervention. Stimuli of the EMOBACK task were positive, negative and neutral words. Our results revealed valence-specific stimulation effects in dependence of colored light exposure. More specifically, task accuracy was significantly increased for positive stimuli under blue light and for negative stimuli under green light exposure. Our findings highlight the importance of state-dependency in studies using non-invasive brain stimulation and show blue light exposure to be a potential adjunctive technique to rTMS for enhancing cognitive-emotional modulation.

scholarly journals LIGHT-INDUCED EFFICIENCY AND PIGMENT ALTERATIONS IN RED ALGAE

1958 ◽  
Vol 41 (6) ◽  
pp. 1113-1117 ◽  
Author(s):  
C. S. Yocum ◽  
L. R. Blinks
Keyword(s):  
Blue Light ◽  
Red Algae ◽  
Photosynthetic Efficiency ◽  
High Efficiency ◽  
Light Exposure ◽  
Action Spectrum ◽  
Green Light ◽  
Chromatic Adaptation ◽  
Carotenoid Pigments ◽  
Low Efficiency

The low photosynthetic efficiency of chlorophyll in freshly collected red algae, can, in the case of Porphyra perforata, P. nereocystis, and Porphyridium cruentum, be increased by growing the algae for 10 days in red or blue light. Exposure to darkness or to green light maintains the algae in their originally low efficiency with respect to chlorophyll, while retaining the high efficiency of phycobilins. Red- or blue-adapted algae are rapidly reversed by exposure to green light, the chlorophyll efficiency dropping to low values again in a few hours. This is assumed to account for the action spectrum of freshly gathered plants. Some pigment changes were observed, but not in the direction of "chromatic adaptation;" and the carotenoid pigments were not activated, even by blue light, but remained as photosynthetically inactive shading filters. The higher red algae (Florideae) did not show activation of chlorophyll by red or blue light.

Nighttime Blue Light Exposure and Breast Cancer

2021 ◽  
pp. 30-33
Author(s):  
David Jaynes ◽  
Paul Switzer
Keyword(s):  
Breast Cancer ◽  
Risk Factor ◽  
Blue Light ◽  
Shift Work ◽  
Light Exposure ◽  
Night Shift ◽  
Background Information ◽  
Common Disease ◽  
Essential Information ◽  
Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

scholarly journals α-Synuclein-induced dysregulation of neuronal activity contributes to murine dopamine neuron vulnerability

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Abeer Dagra ◽  
Douglas R. Miller ◽  
Min Lin ◽  
Adithya Gopinath ◽  
Fatemeh Shaerzadeh ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Neuronal Activity ◽  
Dopaminergic Neurons ◽  
Prolonged Exposure ◽  
D2 Receptor ◽  
Neuronal Firing ◽  
Dopamine Neurons ◽  
Loss Of Function ◽  
Therapeutic Implications

AbstractPathophysiological damages and loss of function of dopamine neurons precede their demise and contribute to the early phases of Parkinson’s disease. The presence of aberrant intracellular pathological inclusions of the protein α-synuclein within ventral midbrain dopaminergic neurons is one of the cardinal features of Parkinson’s disease. We employed molecular biology, electrophysiology, and live-cell imaging to investigate how excessive α-synuclein expression alters multiple characteristics of dopaminergic neuronal dynamics and dopamine transmission in cultured dopamine neurons conditionally expressing GCaMP6f. We found that overexpression of α-synuclein in mouse (male and female) dopaminergic neurons altered neuronal firing properties, calcium dynamics, dopamine release, protein expression, and morphology. Moreover, prolonged exposure to the D2 receptor agonist, quinpirole, rescues many of the alterations induced by α-synuclein overexpression. These studies demonstrate that α-synuclein dysregulation of neuronal activity contributes to the vulnerability of dopaminergic neurons and that modulation of D2 receptor activity can ameliorate the pathophysiology. These findings provide mechanistic insights into the insidious changes in dopaminergic neuronal activity and neuronal loss that characterize Parkinson’s disease progression with significant therapeutic implications.

scholarly journals Artificial complementary chromatic acclimation gene expression system in Escherichia coli

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Dwi Ariyanti ◽  
Kazunori Ikebukuro ◽  
Koji Sode
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Light Exposure ◽  
Expression System ◽  
Red Light ◽  
Green Light ◽  
Light Illumination ◽  
Multiple Gene ◽  
Gene Expression System ◽  
Chromatic Acclimation

Abstract Background The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the PtrcΔLacO promoter. Results One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the PtrcΔLacO promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed. Conclusion An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.

Effects of pre-bedtime blue-light exposure on ratio of deep sleep in healthy young men

2021 ◽  
Author(s):  
Masao Ishizawa ◽  
Takuya Uchiumi ◽  
Miki Takahata ◽  
Michiyasu Yamaki ◽  
Toshiaki Sato
Keyword(s):  
Blue Light ◽  
Light Exposure ◽  
Young Men ◽  
Deep Sleep
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