NADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islets (PIs) of β-cells through an as yet unknown mechanism. We found NADPH oxidase isoform 4 (NOX4) to be the main producer of cytosolic H2O2, which is essential for GSIS; an increase in ATP alone was insufficient for GSIS. The fast GSIS phase was absent from PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (though not from NOX2 knockout mice) and from NOX4-silenced or catalase-overexpressing INS-1E cells. Lentiviral NOX4 overexpression or H2O2 rescued GSIS in PIs from NOX4βKO mice. NOX4 silencing suppressed Ca2+ oscillations, and the patch-clamped KATP channel opened more frequently when glucose was high. Mitochondrial H2O2, decreasing upon GSIS, provided alternative redox signaling when 2-oxo-isocaproate or fatty acid oxidation formed superoxides through electron-transfer flavoprotein:Q-oxidoreductase. Unlike GSIS, such insulin secretion was blocked with mitochondrial antioxidant SkQ1. Both NOX4 knockout and NOX4βKO mice exhibited impaired glucose tolerance and peripheral insulin resistance. Thus, the redox signaling previously suggested to cause β-cells to self-check hypothetically induces insulin resistance when it is absent. In conclusion, increases in ATP and H2O2 constitute an essential signal that switches on insulin exocytosis for glucose and branched-chain oxoacids as secretagogues (it does so partially for fatty acids). Redox signaling could be impaired by cytosolic antioxidants; hence, those targeting mitochondria should be preferred for clinical applications to treat (pre)diabetes at any stage.

Department of Mitochondrial Physiology No 75 Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic

Institut für Kardiovaskuläre Physiologie Goethe Universität Frankfurt Germany

Institute of Clinical and Experimental Medicine Prague Czech Republic

Klinik für Neurologie Universität Magdeburg Magdeburg Germany

000      

00000naa a2200000 a 4500

001      

bmc20028045

003      

CZ-PrNML

005      

20210114152851.0

007      

ta

008      

210105s2020 xxu f 000 0|eng||

009      

AR

024    7_

$a 10.2337/db19-1130 $2 doi

035    __

$a (PubMed)32245800

040    __

$a ABA008 $b cze $d ABA008 $e AACR2

041    0_

$a eng

044    __

$a xxu

100    1_

$a Plecitá-Hlavatá, Lydie $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

245    10

$a Glucose-Stimulated Insulin Secretion Fundamentally Requires H2O2 Signaling by NADPH Oxidase 4 / $c L. Plecitá-Hlavatá, M. Jabůrek, B. Holendová, J. Tauber, V. Pavluch, Z. Berková, M. Cahová, K. Schröder, RP. Brandes, D. Siemen, P. Ježek,

520    9_

$a NADPH facilitates glucose-stimulated insulin secretion (GSIS) in pancreatic islets (PIs) of β-cells through an as yet unknown mechanism. We found NADPH oxidase isoform 4 (NOX4) to be the main producer of cytosolic H2O2, which is essential for GSIS; an increase in ATP alone was insufficient for GSIS. The fast GSIS phase was absent from PIs from NOX4-null, β-cell-specific knockout mice (NOX4βKO) (though not from NOX2 knockout mice) and from NOX4-silenced or catalase-overexpressing INS-1E cells. Lentiviral NOX4 overexpression or H2O2 rescued GSIS in PIs from NOX4βKO mice. NOX4 silencing suppressed Ca2+ oscillations, and the patch-clamped KATP channel opened more frequently when glucose was high. Mitochondrial H2O2, decreasing upon GSIS, provided alternative redox signaling when 2-oxo-isocaproate or fatty acid oxidation formed superoxides through electron-transfer flavoprotein:Q-oxidoreductase. Unlike GSIS, such insulin secretion was blocked with mitochondrial antioxidant SkQ1. Both NOX4 knockout and NOX4βKO mice exhibited impaired glucose tolerance and peripheral insulin resistance. Thus, the redox signaling previously suggested to cause β-cells to self-check hypothetically induces insulin resistance when it is absent. In conclusion, increases in ATP and H2O2 constitute an essential signal that switches on insulin exocytosis for glucose and branched-chain oxoacids as secretagogues (it does so partially for fatty acids). Redox signaling could be impaired by cytosolic antioxidants; hence, those targeting mitochondria should be preferred for clinical applications to treat (pre)diabetes at any stage.

650    _2

$a zvířata $7 D000818

650    _2

$a vápník $x metabolismus $7 D002118

650    _2

$a kultivované buňky $7 D002478

650    _2

$a glukosa $x farmakologie $7 D005947

650    _2

$a peroxid vodíku $x metabolismus $7 D006861

650    _2

$a inzulinová rezistence $7 D007333

650    12

$a sekrece inzulinu $7 D000078790

650    _2

$a myši $7 D051379

650    _2

$a myši inbrední C57BL $7 D008810

650    _2

$a NADPH-oxidasa 4 $x fyziologie $7 D000074663

650    _2

$a draslíkové kanály $x fyziologie $7 D015221

650    _2

$a signální transdukce $x fyziologie $7 D015398

655    _2

$a časopisecké články $7 D016428

655    _2

$a práce podpořená grantem $7 D013485

700    1_

$a Jabůrek, Martin $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

700    1_

$a Holendová, Blanka $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

700    1_

$a Tauber, Jan $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

700    1_

$a Pavluch, Vojtěch $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic.

700    1_

$a Berková, Zuzana $u Institute of Clinical and Experimental Medicine, Prague, Czech Republic.

700    1_

$a Cahová, Monika $u Institute of Clinical and Experimental Medicine, Prague, Czech Republic.

700    1_

$a Schröder, Katrin $u Institut für Kardiovaskuläre Physiologie, Goethe-Universität, Frankfurt, Germany.

700    1_

$a Brandes, Ralf P $u Institut für Kardiovaskuläre Physiologie, Goethe-Universität, Frankfurt, Germany.

700    1_

$a Siemen, Detlef $u Klinik für Neurologie, Universität Magdeburg, Magdeburg, Germany.

700    1_

$a Ježek, Petr $u Department of Mitochondrial Physiology, No. 75, Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic jezek@biomed.cas.cz.

773    0_

$w MED00001379 $t Diabetes $x 1939-327X $g Roč. 69, č. 7 (2020), s. 1341-1354

856    41

$u https://pubmed.ncbi.nlm.nih.gov/32245800 $y Pubmed

910    __

$a ABA008 $b sig $c sign $y a $z 0

990    __

$a 20210105 $b ABA008

991    __

$a 20210114152849 $b ABA008

999    __

$a ok $b bmc $g 1608380 $s 1119225

BAS    __

$a 3

BAS    __

$a PreBMC

BMC    __

$a 2020 $b 69 $c 7 $d 1341-1354 $e 20200403 $i 1939-327X $m Diabetes $n Diabetes $x MED00001379

LZP    __

$a Pubmed-20210105