Book of Abstracts - New Frontiers 2022

Abstracts of poster presentations

DICHLOROACETATE AND REDUCED OXYGEN UTILIZATION IN THE HEART: REGULATION OF THE MITOCHONDRIAL PROTEOME

N. Andelova 1 , I. Waczulikova 2 , I. Talian 3 , T. Ravingerova 1 , M. Ferko 1

1 Centre of Experimental Medicine, Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovakia; 2 Comenius University, Department of Nuclear Physics & Biophysics, Faculty of Mathematics, Physics and Informatics, Bratislava, Slovakia; 3 Safarik University, Department of Medical and Clinical Biophysics, Faculty of Medicine, Kosice, Slovakia Myocardial compensatory mechanisms stimulated by reduced oxygen utilization caused by streptozotocin induced diabetes mellitus (D) and treated with the metabolic modulator dichloroacetate (DCA) are presumably associated with the regulation of mitochondria. Processes of inhibiting mitochondrial permeability transition pores (mPTP) opening lead to the maintenance of adequate ATP production and so represent an essential and beneficial cardioprotective strategy. Here we aimed to expand knowledge about key signaling pathways linked to regulation of mPTP opening, ROS and calcium signaling in the conditions of D treated with the DCA. Isolated Wistar rat heart mitochondria were used for fluorescence-spectroscopy measurements and quantitative label-free LC-MS/MS proteomic analysis focused on the proteins forming and regulating mPTP complex and proteins linked to ROS production. The acute 8-day D model (65 mg/kg streptozotocin i.p.) was exposed to DCA administered to animals (150 mg/kg and 75 mg/kg i.p.) 60 minutes and 15 minutes before heart excision. We revealed significantly upregulated protein amine oxidase [flavin-containing] A (AOFA) in D mitochondria, indicative of oxidative damage. DCA in diabetic animals (D+DCA) downregulated AOFA and stimulated thioredoxin-dependent peroxide reductase, a protein with antioxidant function. D group exhibited stimulation to the highest aggregated abundance of the mPTP proteins. Furthermore, the D condition was associated with mitochondrial resistance to calcium-overload through mPTP regulation, despite an increased protein level of voltage-dependent anion-selective protein (VDAC1). In contrast, D+DCA influenced ROS levels and downregulated VDAC1 and VDAC3 when compared to D alone. Characterization of the combined effect of D+DCA is a novel finding showing that DCA acted as an effector of calcium uptake regulation and ROS production. Overall, the achieved results expanded the available knowledge about mitochondrial signaling pathways in the rat heart that can lead to cardioprotection during reduced oxygen utilization induced by D.

Keywords: cardiac mitochondrial proteome, cardioprotective signaling, reduced oxygen utilization, mPTP, dichloroacetate

Funding:This study was supported by APVV 15-0119, APVV 19-0540, VEGA 2/0121/18, VEGA 2/0141/18, VEGA 1/0016/20 and ITMS 26230120009.

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