Glutathione S-Transferase Protein Expression in Different Life Stages of Zebrafish (Danio rerio)

Abstract

Zebrafish is a widely used animal model in biomedical sciences and toxicology. Although evidence for the presence of phases I and II xenobiotic defense mechanisms in zebrafish exists on the transcriptional and enzyme activity level, little is known about the protein expression of xenobiotic metabolizing enzymes. Given the important role of glutathione S-transferases (GSTs) in phase II biotransformation, we analyzed cytosolic GST proteins in zebrafish early life stages and different organs of adult male and female fish, using a targeted proteomics approach. The established multiple reaction monitoring-based assays enable the measurement of the relative abundance of specific GST isoenzymes and GST classes in zebrafish through a combination of proteotypic peptides and peptides shared within the same class. GSTs of the classes alpha, mu, pi and rho are expressed in zebrafish embryo as early as 4 h postfertilization (hpf). The majority of GST enzymes are present at 72 hpf followed by a continuous increase in expression thereafter. In adult zebrafish, GST expression is organ dependent, with most of the GST classes showing the highest expression in the liver. The expression of a wide range of cytosolic GST isoenzymes and classes in zebrafish early life stages and adulthood supports the use of zebrafish as a model organism in chemical-related investigations.

Mapping glutathione utilization in the developing zebrafish (Danio rerio) embryo

“…To determine that MCB conjugation was Gst mediated in zebrafish embryos, and consequently, representative of the glutathione utilization, we treated 48 hpf embryos with 100 μM ethacrynic acid (ETA) for 30 min or 1 h prior to MCB staining and imaging. ETA is a specific Gstπ inhibitor; Gstπ is the predominant isozyme in zebrafish at these early embryonic stages, with two paralogs Gstπ1 & Gstπ2 [24,49]. A 30-min treatment with ETA was insufficient to cause any significant changes in glutathione utilization across all measured structures (Supp.…”

“…GSTs conjugate GSH to xenobiotics; these GS-conjugates can often be readily excreted, providing living systems with an efficient method to combat toxic insults. GST expression however, is highly spatiotemporally divergent in vertebrates, leading to differential susceptibilities and sensitivities of organ systems during development [[24], [25], [26], [27]]. Furthermore, disruptions in the GSH E h during organogenesis cause altered glutathionylation of spliceosome related proteins leading to dysregulation of normal signaling in rat fetuses; these alterations occur to different degrees in different embryonic compartments, underscoring the need to better characterize spatiotemporal glutathione redox dynamics during embryogenesis [28].…”

“…Previous studies have compared various small thiol dyes and found that MCB displays greater specificity for GSH than other thiol dyes [47,48]. In the zebrafish, the Gst isozyme superfamily has been well-characterized both during development and in adult fish [24]. MCB is known to be a substrate for all the known zebrafish GST isozymes, with Gstτ1a having the lowest affinity and Gstπ1 having the highest affinity [49].…”

MGST1, a GSH transferase/peroxidase essential for development and hematopoietic stem cell differentiation

“…In addition, an enhanced sensitivity to pro-oxidants has been described at 72 hpf [44] , in zebrafish, an observation that fits well with the noted MGST1 decline. With few exceptions, other GSTs do not show a developmental peak in zebrafish development [45] .…”

Proteomic Responses Under Cold Stress Reveal Unique Cold Tolerance Mechanisms in the Pacific White Shrimp (Litopenaeus vannamei)

“…Our results indicate that free radical stress scavenging enzymes played key roles in white shrimp under cold stress in these experiments, consistent with studies in other species. For example, cold treatment has been shown to cause significant changes in GST ( Tierbach et al, 2018 ), LRR domains, tetraspanin CD63 ( Li G. et al, 2014 ; Chaiyadet et al, 2017 ), m7GpppX pyrophosphatase ( Malys et al, 2004 ), zinc proteinase ( Loewy et al, 1993 ), and different types of lectin protein families (Figures 5 , 6 ). GSTs play important roles in insecticide/drug resistance and stress response in insects ( Sookrung et al, 2018 ), rats ( Wang et al, 2018 ; Yang et al, 2018 ), and the plant species Arabidopsis thaliana ( Banday and Nandi, 2018 ).…”