Proceedings of The Physiological Society

Mitochondria: Form and function (London, UK) (2017) Proc Physiol Soc 38, C10

Oral Communications

Evaluation of a novel mitochondria-targeted peptide based H2S donor compound (RTP-10) in hyperglycaemia-induced microvascular endothelial cell dysfunction

R. Torregrossa1, A. Waters1, D. Gero2, A. Perry1, S. Webb3, C. Rush3, M. Wood1, M. Whiteman1

1. University of Exeter, Exeter, Devon, United Kingdom. 2. Institute of Pathophysiology, Faculty of Medicine, Semmelweis University, Semmelweis, Hungary. 3. ISCA Biochemicals, Exeter, Exeter, Devon, United Kingdom.

An overproduction of mitochondrial reactive oxygen species (ROS) in endothelial cells, is a major contributor to vascular endothelial dysfunction (VED) and angiopathy in diabetes [1]. Hyperglycaemia (HG) induces metabolic changes in mitochondria, notably superoxide production, membrane hyperpolarisation and loss of ATP synthesis [2]. Supplementation of cells and diabetic animals with sources of hydrogen sulfide (H2S) has been shown to protects mitochondria from the detrimental effects of oxidative stress (e.g. in hypoxia/ischaemia-reperfusion injury, diabetic angiopathy, stroke etc.) as well as reverse vascular damage in animal models of diabetes in vivo [3]. Moreover H2S has been shown to prevent HG-induced metabolic changes in vascular endothelial cells. Given the predominantly mitochondrial effects of H2S against diabetic vascular damage, we previously described two mitochondria-targeted H2S (mtH2SD) donor organic compounds based around a triphenylphosphonium (TPP+) targeting scaffold, AP39 [4] and AP123 [5]. These compounds have shown significant efficacy in animal models of mitochondrial dysfunction at very low doses (7-300 µg / kg). In this current study, we have used an alternative approach to target H2S to mitochondria using a novel H2S donor derivative of D-Arg-L-Tyr-L-Lys-L-Phe-NH2 (RTP-10). This approach may be advantageous over TPP+-based scaffolds as mitochondrial accumulation is not dependent on mitochondrial ΔΨm. We therefore exposed murine B.End3 brain microvascular endothelial cells to hyperglycaemia (HG) and after 7 days added RTP-10 and measured the reversal of HG-induced metabolic changes, specifically mitochondrial ΔΨm (JC-1), mitochondrial superoxide (mitosox), ATP synthesis (by luminescence). RTP-10 caused a concentration-dependent (0.1-30 µM) increase in mitochondrial H2S levels and reversed HG-induced mitochondrial hyperpolarisation and oxidant production, and restored ATP synthesis. Our study further suggests that targeting H2S to mitochondria may be a useful therapeutic strategy for preventing/inhibiting HG-induced VED and angiopathy.

Where applicable, experiments conform with Society ethical requirements