The transcriptional response of skin to fluorescent light exposure in viviparous (Xiphophorus) and oviparous (Danio, Oryzias) fishes

Abstract

Differences in light sources are common in animal facilities and potentially can impact experimental results. Here, the potential impact of lighting differences on skin transcriptomes has been tested in three aquatic animal models commonly utilized in biomedical research, (Xiphophorus maculatus (platyfish), Oryzias latipes (medaka) and Danio rerio (zebrafish). Analysis of replicate comparative RNA-Seq data showed the transcriptional response to commonly utilized 4100K or "cool white" fluorescent light (FL) is much greater in platyfish and medaka than in zebrafish. FL induces genes associated with inflammatory and immune responses in both medaka and zebrafish; however, the platyfish exhibit suppression of genes involved with immune/inflammation, as well as genes associated with cell cycle progression. Furthermore, comparative analyses of gene expression data from platyfish UVB exposures, with medaka and zebrafish after exposure to 4100K FL, show comparable effects on the same stress pathways. We suggest the response to light is conserved, but that long-term adaptation to species specific environmental niches has resulted in a shifting of the wavelengths required to incite similar "genetic" responses in skin. We forward the hypothesis that the "genetic perception" of light may have evolved differently than ocular perception and suggest that light type (i.e., wavelengths emitted) is an important parameter to consider in experimental design.

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.…”

Effects of photoperiod on growth performance and melanogenesis pathway for skin pigmentation of Malaysian red tilapia

“…Light produces specific wavelength bands, which affect genes and the transcription factors in the skin of fish (Chang et al, 2015;Gonzalez et al, 2017). The effect of light has been studied in model aquatic organisms such as platyfish, Xiphophorus maculatus, zebrafish, Danio rerio and Medaka, Oryzias latipes (Boswell et al, 2018). Skin is the first organ, which receives direct interaction with In this study, the mRNA expression of sox 10, tyr, slc7a11 and tyrp-1 genes in red tilapia was directly affected by light duration, similar to results obtained in Oreolalax rhodostigmatus .…”