Detection of changes in mitochondrial hydrogen sulfide i n vivo in the fish model Poecilia mexicana (Poeciliidae).

Gigi Y Lau,Nicholas Barts,Michael Tobler,Michael P Murphy,Sabine Arndt,Richard C Hartley,Jeffrey G Richards

doi:10.1242/bio.041467

Abstract

ABSTRACTIn this paper, we outline the use of a mitochondria-targeted ratiometric mass spectrometry probe, MitoA, to detect in vivo changes in mitochondrial hydrogen sulfide (H2S) in Poecilia mexicana (family Poeciliidae). MitoA is introduced via intraperitoneal injection into the animal and is taken up by mitochondria, where it reacts with H2S to form the product MitoN. The MitoN/MitoA ratio can be used to assess relative changes in the amounts of mitochondrial H2S produced over time. We describe the use of MitoA in the fish species P. mexicana to illustrate the steps for adopting the use of MitoA in a new organism, including extraction and purification of MitoA and MitoN from tissues followed by tandem mass spectrometry. In this proof-of-concept study we exposed H2S tolerant P. mexicana to 59 µM free H2S for 5 h, which resulted in increased MitoN/MitoA in brain and gills, but not in liver or muscle, demonstrating increased mitochondrial H2S levels in select tissues following whole-animal H2S exposure. This is the first time that accumulation of H2S has been observed in vivo during whole-animal exposure to free H2S using MitoA. This article has an associated First Person interview with the first author of the paper.

Highlights

Before the rise in atmospheric oxygen (O2) levels ∼800 million years ago, oceans were euxinic; that is, both anoxic and sulfidic
Our optimization and proof-of-principle studies showed that MitoA could be used in P. mexicana exposed to high environmental H2S to detect in vivo changes in mitochondrial H2S
Part 1: optimizing use of MitoA in P. mexicana The goal of this initial 28 h time course experiment was to determine if P. mexicana tissues showed MitoA uptake and whether the probe would be retained for H2S exposure experiments of 4 h duration

Summary

Introduction

Before the rise in atmospheric oxygen (O2) levels ∼800 million years ago, oceans were euxinic; that is, both anoxic and sulfidic. The rise in O2 was associated with an increased abundance of cyanobacteria and plants that are thought to have eliminated sulphide, which was an abundant energy source (Olson and Straub, 2016). Hydrogen sulfide (H2S) still retained an important role in cellular function, G.Y.L., 0000-0002-0448-5071; M.P.M., 0000-0003-1115-9618; S.A., 0000-00026728-0479. The pathway for H2S regulation is highly conserved across modern taxa (Olson and Straub, 2016)

Methods

Results

Conclusion