Mitochondrial Superoxide Production Decreases on Glucose-Stimulated Insulin Secretion in Pancreatic beta Cells Due to Decreasing Mitochondrial Matrix NADH/NAD(+) Ratio

0532352 - FGÚ 2021 RIV US eng J - Článek v odborném periodiku
Plecitá-Hlavatá, Lydie - Engstová, Hana - Holendová, Blanka - Tauber, Jan - Špaček, Tomáš - Petrásková, Lucie - Křen, Vladimír - Špačková, Jitka - Gotvaldová, Klára - Ježek, Jan - Dlasková, Andrea - Smolková, Katarína - Ježek, Petr
Mitochondrial Superoxide Production Decreases on Glucose-Stimulated Insulin Secretion in Pancreatic beta Cells Due to Decreasing Mitochondrial Matrix NADH/NAD(+) Ratio.
Antioxidants & Redox Signaling. Roč. 33, č. 12 (2020), s. 789-815. ISSN 1523-0864. E-ISSN 1557-7716
Grant CEP: GA ČR(CZ) GA16-06700S; GA ČR(CZ) GA17-01813S; GA ČR(CZ) GA20-00408S
Institucionální podpora: RVO:67985823 ; RVO:61388971
Klíčová slova: mitochondrial superoxide generation * pancreatic beta cells * glucose-stimulated insulin secretion * Complex I * NADH/NAD(+) ratio * fluorescence lifetime imaging
Obor OECD: Endocrinology and metabolism (including diabetes, hormones); Analytical chemistry (MBU-M)
Impakt faktor: 8.401, rok: 2020
Způsob publikování: Open access
https://www.liebertpub.com/doi/10.1089/ars.2019.7800

Aims:Glucose-stimulated insulin secretion (GSIS) in pancreatic beta cells was expected to enhance mitochondrial superoxide formation. Hence, we elucidated relevant redox equilibria. Results:Unexpectedly, INS-1E cells at transitions from 3 (11 mM, pancreatic islets from 5 mM) to 25 mM glucose decreased matrix superoxide release rates (MitoSOX Red monitoring validated by MitoB) and H2O2(mitoHyPer, subtracting mitoSypHer emission). Novel double-channel fluorescence lifetime imaging, approximating free mitochondrial matrix NADH(F,)indicated its similar to 20% decrease. Matrix NAD(F)(+)increased on GSIS, indicated by the FAD-emission lifetime decrease, reflecting higher quenching of FAD by NAD(F)(+). The participation of pyruvate/malate and pyruvate/citrate redox shuttles, elevating cytosolic NADPH(F)(iNAP1 fluorescence monitoring) at the expense of matrix NADH(F), was indicated, using citrate (2-oxoglutarate) carrier inhibitors and cytosolic malic enzyme silencing: All changes vanished on these manipulations.C-13-incorporation from C-13-L-glutamine into C-13-citrate reflected the pyruvate/isocitrate shuttle. Matrix NADPH(F)(iNAP3 monitored) decreased. With decreasing glucose, the suppressor of Complex III site Q electron leak (S3QEL) suppressor caused a higher Complex I I(F)site contribution, but a lower superoxide fraction ascribed to the Complex III site IIIQo. Thus, the diminished matrix NADH(F)/NAD(F)(+) decreased Complex I flavin site I(F)superoxide formation on GSIS. Innovation:Mutually validated methods showed decreasing superoxide release into the mitochondrial matrix in pancreatic beta cells on GSIS, due to the decreasing matrix NADH(F)/NAD(F)(+) (NADPH(F)/NADP(F)(+)) at increasing cytosolic NADPH(F) levels. The developed innovative methods enable real-time NADH/NAD(+)and NADPH/NADP(+) monitoring in any distinct cell compartment. Conclusion:The export of reducing equivalents from mitochondria adjusts lower mitochondrial superoxide production on GSIS, but it does not prevent oxidative stress in pancreatic beta cells.
Trvalý link: http://hdl.handle.net/11104/0310854