ABC transporters and xenobiotic defense systems in early life stages of rainbow trout (Oncorhynchus mykiss)

Abstract

Embryos of oviparous fish, in contrast to (ovo) viviparous species, develop in the aquatic environment, and therefore need solute transport systems at their body surfaces for maintaining internal homeostasis and defending against potentially harmful substances. We hypothesized that solute transporters undergo changes in tissue distribution from the embryo to the larval stage. We therefore studied the mRNA profiles of eight ABC transporters (abcb1a, abcb1b, abcc1, abcc2, abcc3, abcc4, abcc5, abcg2) and three solute carriers (oatp1d, putative oatp2 putative, mate1) in different body regions (head, yolk sac epithelium, abdominal viscera, skin/muscles) of developing rainbow trout. Additionally, we investigated mRNA levels of phase I (cyp1a, cyp3a) and phase II (gstp, putative ugt1, putative ugt2) biotransformation enzymes. The study covered the developmental period from the eleuthero-embryo stage to the first-feeding larval stage (1-20days post-hatch, dph). At 1dph, transcripts of abcc2, abcc4, abcg2, cyp3a, gstp, putative mate1, and putative oatp2 occurred primarily in the yolk sac epithelium, whereas at later stages expression of these genes was predominantly observed in the abdominal viscera. The functional activity of ABC transporters in fish early life stages was assessed by rhodamine B accumulation assays. Finally, we investigated the potential impact of xenobiotics (clotrimazole, clofibric acid) on the ABC and biotransformation systems of trout early life stages. While clofibric acid had no effect, clotrimazole lead to an increased rhodamine B accumulation. The results provide evidence that the transition from the eleuthero-embryo to the larval stage is accompanied by a major alteration in tissue expression of ABC transporters.

Effects of diclofenac on the expression of Nrf2 and its downstream target genes in mosquito fish (Gambusia affinis)

“…No significant change was observed for UGTs at 24 h under DCF exposure. Kropf et al also found the mRNA expression of UGTs had changes but no significant differences in early life stages of rainbow trout (Kropf et al, 2016), similar to the UGT performance in the present study. But with the prolonged exposure time, UGT gene expression exhibited inverted "U"-shape change pattern with rising concentrations at 168 h, and similar changes was observed in the livers of Nile tilapia (Thummabancha et al, 2016).…”

Rhodamine B degradation by nanosized zeolitic imidazolate framework-8 (ZIF-8)

“…Additionally, RhB is detrimental to the environment with evidence of long lasting effects to aquatic life. 22 Despite being known as a carcinogenic compound, it is used illegally as a food dye in many countries. 23 Moreover, RhB is stable in water in a wide pH range and not biodegradable; therefore, it should be fully removed or decomposed before releasing RhB-containing wastewater to the environment.…”

Expression and Function of ABC Proteins in Fish Intestine

“…Reports on fish Abcg1 are available only for zebrafish lipid metabolism and related human diseases (atherosclerosis and angiogenesis) ( Fang et al, 2013 , 2014 for a review). Abcg2 is the most studied member of this subfamily in fish as an essential protein concerning xenobiotics detoxification ( Paetzold et al, 2009 ; Kropf et al, 2016 ; Zaja et al, 2016 , among others). ( Zhang L. et al, 2020 ) characterized zebrafish abcg5 and abcg8.…”