Assessment of H2S in vivo using the newly developed mitochondria-targeted mass spectrometry probe MitoA

Abstract

Hydrogen sulfide (H2S) is produced endogenously in vivo and has multiple effects on signaling pathways and cell function. Mitochondria can be both an H2S source and sink, and many of the biological effects of H2S relate to its interactions with mitochondria. However, the significance of mitochondrial H2S is uncertain, in part due to the difficulty of assessing changes in its concentration in vivo. Although a number of fluorescent H2S probes have been developed these are best suited to cells in culture and cannot be used in vivo. To address this unmet need we have developed a mitochondria-targeted H2S probe, MitoA, which can be used to assess relative changes in mitochondrial H2S levels in vivo. MitoA comprises a lipophilic triphenylphosphonium (TPP) cation coupled to an aryl azide. The TPP cation leads to the accumulation of MitoA inside mitochondria within tissues in vivo. There, the aryl azido group reacts with H2S to form an aryl amine (MitoN). The extent of conversion of MitoA to MitoN thus gives an indication of the levels of mitochondrial H2S in vivo. Both compounds can be detected sensitively by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis of the tissues, and quantified relative to deuterated internal standards. Here we describe the synthesis and characterization of MitoA and show that it can be used to assess changes in mitochondrial H2S levels in vivo. As a proof of principle we used MitoA to show that H2S levels increase in vivo during myocardial ischemia.

Convergent evolution of conserved mitochondrial pathways underlies repeated adaptation to extreme environments

“…1 C ; habitat × H 2 S: P < 0.001 in SI Appendix , Table S5 ), likely helping fish from sulfidic habitats to maintain H 2 S homeostasis during environmental exposure. To test this prediction in vivo, we used a novel mitochondria-specific H 2 S-probe (MitoA) that allows for the monitoring of relative H 2 S levels inside the mitochondria of living organisms ( 16 ). We measured mitochondrial H 2 S concentrations in this manner using laboratory-reared fish that were exposed to varying levels of environmental H 2 S. Because laboratory-reared fish were not available for the population pair from Pich, only two population pairs were used for this analysis.…”

Strain-specificity in the hydrogen sulphide signalling network following dietary restriction in recombinant inbred mice

“…In addition, it will also be interesting to investigate precisely how H 2 S production varies in different tissues and in different cellular locations following DR. These approaches may be made more feasible with the advent of novel chemical probes to determine H 2 S in vivo (Arndt et al 2017;Lau et al 2019). However, irrespective of these caveats, we have shown that endogenous H 2 S levels and associated signalling pathways differ significantly depending on genetic background in mice under both AL and DR conditions.…”

Extended hypoxia‐mediated H2S production provides for long‐term oxygen sensing

“…This hypothesis has been supported by numerous observations in a variety of vertebrates that have shown; (1) hypoxia and H 2 S produce identical responses in a wide variety of physiological systems, (2) compounds that stimulate or inhibit H 2 S production often stimulate or inhibit hypoxic responses, (3) failure of H 2 S oxidation occurs at physiologically relevant P o 2 thereby increasing tissue H 2 S concentration and (4) O 2 ‐sensitive H 2 S metabolism occurs in the mitochondria (reviewed in). Furthermore, hypoxia has recently been shown to increase H 2 S concentration in mitochondria of myocardial cells furthering the case for mitochondrially mediated H 2 S production in O 2 sensing.…”