Fluorescent Light Incites a Conserved Immune and Inflammatory Genetic Response within Vertebrate Organs (Danio rerio, Oryzias latipes and Mus musculus)

Abstract

Fluorescent light (FL) has been utilized for ≈60 years and has become a common artificial light source under which animals, including humans, spend increasing amounts of time. Although the solar spectrum is quite dissimilar in both wavelengths and intensities, the genetic consequences of FL exposure have not been investigated. Herein, we present comparative RNA-Seq results that establish expression patterns within skin, brain, and liver for Danio rerio, Oryzias latipes, and the hairless mouse (Mus musculus) after exposure to FL. These animals represent diurnal and nocturnal lifestyles, and ≈450 million years of evolutionary divergence. In all three organisms, FL induced transcriptional changes of the acute phase response signaling pathway and modulated inflammation and innate immune responses. Our pathway and gene clustering analyses suggest cellular perception of oxidative stress is promoting induction of primary up-stream regulators IL1B and TNF. The skin and brain of the three animals as well as the liver of both fish models all exhibit increased inflammation and immune responses; however, the mouse liver suppressed the same pathways. Overall, the conserved nature of the genetic responses observed after FL exposure, among fishes and a mammal, suggest the presence of light responsive genetic circuitry deeply embedded in the vertebrate genome.

“Photobiomics”: Can Light, Including Photobiomodulation, Alter the Microbiome?

“…It is also apparent that blue light-emitting diode (LED) screens and lights used at night can suppress melatonin secretion and affect circadian rhythms with consequent effects on health 26 and it has also been demonstrated that red light (morning light) in humans can influence both leptin and ghrelin concentrations, 27 which play a role in energy homeostasis, hunger, and satiety. Recently, Basha and colleagues 28 have shown that fluorescent lighting can affect the oxidative stress of rats and Boswell and colleagues have shown that fluorescent lighting can have effects on gene regulation and inflammatory processes, 29 which have the potential to affect the microbiome.…”

Deconvoluting Wavelengths Leading to Fluorescent Light Induced Inflammation and Cellular Stress in Zebrafish (Danio rerio)

“…Waveband responses in skin. As previously reported, the FL response in zebrafish skin, brain and liver is controlled through the IL1B regulator and conserved up-modulation of the Acute Phase Response signaling pathway (APR 1,2 ). This pathway and others promote a conserved inflammatory and immune response throughout the animal.…”

“…FL exposure (35 kJ/m 2 ) was performed as previously detailed. All protocols were carried out as previously described 1,2 . Prior to light exposure, fish were placed individually into 100 mL of filtered home aquaria water and kept in the dark for 14 hrs.…”

“…FL exposure occurred in UV-transparent cuvettes (9 cm × 7.5 cm × 1.5 cm) in 90 mL of water. The exposure cuvettes were suspended 10 cm between two banks of two (total of 4 lights) unfiltered 4,100 K fluorescent lights (Philips F 20T12/CW 20 watts, Alto) mounted horizontally on each side of a wooden box exposure chamber 1,2 . After FL exposure, all fish were returned to the dark in 100 mL filtered aquaria water for 6 hrs and then euthanized and dissected for RNA isolation.…”

“…These experiments [1][2][3][4] and others [5][6][7] were the first to characterize the genetic response of an intact animal to various light sources and/or specific wavelengths. However, they do not directly address the question of how FL induces highly conserved inflammatory and cellular immune responses initiated by the IL1B regulator, in both a direct light receiving organ and internal organs.…”