H2S-producing enzymes in anoxia-tolerant vertebrates: Effects of cold acclimation, anoxia exposure and reoxygenation on gene and protein expression

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 2020-06, Vol.243-244, p.110430, Article 110430
• Main Authors: Melleby, Arne O., Sandvik, Guro K., Couturier, Christine S., Nilsson, Göran E., Stecyk, Jonathan A.W.
• Format: Article
• Language: English
• Subjects: 3-mercaptopyruvate sulfurtransferase; Carassius carassius; Crucian carp; Cystathionine β-synthase; Cystathionine γ-lyase; Red-eared slider; Trachemys scripta
• ISSN: 1096-4959; 1879-1107
• DOI: 10.1016/j.cbpb.2020.110430

To lend insight into the potential role of the gasotransmitter hydrogen sulfide (H2S) in facilitating anoxia survival of anoxia-tolerant vertebrates, we quantified the gene expression of the primary H2S-synthesizing enzymes, 3-mercaptopyruvate sulfurtransferase (3MST), cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS), in ventricle and brain of normoxic, anoxic and reoxygenated 21 °C- and 5 °C-acclimated freshwater turtles (Trachemys scripta) and 10 °C-acclimated crucian carp (Carassius carassius). Semi-quantitative Western blotting analysis was also conducted to assess 3MST and CBS protein abundance in ventricle and brain of 5 °C turtles and 10 °C crucian carp subjected to normoxia, anoxia and reoxygenation. We hypothesized that if H2S was advantageous for anoxia survival, expression levels would remain unchanged or be upregulated with anoxia and/or reoxygenation. Indeed, for both species, gene and protein expression were largely maintained with anoxia exposure (24 h, 21 °C; 5 d, 10 °C; 14 d, 5 °C). With reoxygenation, 3MST expression was increased in turtle and crucian carp brain at the protein and gene level, respectively. Additionally, the effect of cold acclimation on gene expression was assessed in several tissues of the turtle. Expression levels were maintained in most tissues, but decreased in others. The maintenance of gene and protein expression of the H2S-producing enzymes with anoxia exposure and the up-regulation of 3MST with reoxygenation suggests that H2S may facilitate anoxic survival of the two champions of vertebrate anoxia survival. The differential effects of cold acclimation on H2S enzyme expression may influence blood flow to different tissues during winter anoxia. [Display omitted] •The red-eared slider turtle and the crucian carp are two of the champions of vertebrate anoxia survival.•Effects of oxygenation state on gene and protein expression of H2S-producing enzymes in ventricle and brain were examined.•For both species, gene and protein expression were largely maintained with anoxia exposure and reoxygenation.•Endogenous production of H2S by 3MST, CSE and CBS in the turtle and crucian carp may be important for anoxia survival.