Mitochondrial Dysfunction Contributes to Impaired Insulin Secretion in INS-1 Cells with Dominant-negative Mutations of HNF-1α and in HNF-1α-deficient Islets

Pongratz, Rebecca L.; Kibbey, Richard G.; Kirkpatrick, Clare L.; Zhao, Xiaojie; Pontoglio, Marco; Yaniv, Moshe; Wollheim, Claes B.; Shulman, Gerald I.; Cline, Gary W.

doi:10.1074/jbc.m807723200

Cited by 27 publications

(32 citation statements)

References 40 publications

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“…Previously, we demonstrated a reduction in expression of pyruvate kinase over this time scale after dominant-negative suppression of HNF1A function (8). Indeed, numerous other downstream target genes involved in energy metabolism have been shown to be downregulated 24 h after suppression (9). This study correlated expression of DN-HNF1A with a significant decrease in the level of glucose transporter glut2 mRNA (Fig.…”

Section: Expression Of Dn-hnf1a Causes Bioenergetic Dysfunction Inmentioning

confidence: 61%

“…In particular, the expressions of the Glut2 glucose transporter and pyruvate kinase have been consistently shown to be reduced by dominant-negative suppression of HNF1A function (2,3,8,9). Mitochondrial targets have also been identified, including decreased expression of the E1 subunit of 2-oxoglutarate dehydrogenase and increased levels of the uncoupling protein UCP2 (2,3).…”

mentioning

confidence: 96%

“…The ATP response to glucose in INS-1 cells is diminished by dominant-negative suppression of HNF1A function, with mitochondrial dysfunction thought to contribute to this effect (9). In this study, we examined the response of NAD(P)H autofluorescence to increased extracellular glucose in single cells, and in parallel we monitored the membrane potential response using TMRM.…”

Section: Expression Of Dn-hnf1a Causes Bioenergetic Dysfunction Inmentioning

confidence: 99%

“…Energy metabolism is intrinsically coupled to fuel-stimulated insulin secretion in beta cells with the intracellular ATP/ADP ratio serving as the primary messenger controlling the plasma membrane potential, which in turn regulates the insulin exocytotic machinery (10). Recent evidence indicates that mitochondrial dysfunction contributes to the impaired insulin secretion response to glucose (9), the primary defect in the pathogenesis of HNF1A-MODY.…”

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confidence: 99%

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AMP-activated Protein Kinase Mediates Apoptosis in Response to Bioenergetic Stress through Activation of the Pro-apoptotic Bcl-2 Homology Domain-3-only Protein BMF

Kilbride

Farrelly

Bonner

et al. 2010

Journal of Biological Chemistry

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Heterozygous loss-of-function mutations in the hepatocyte nuclear factor 1A (HNF1A) gene result in the pathogenesis of maturity-onset diabetes-of-the-young type 3, (HNF1A-MODY). This disorder is characterized by a primary defect in metabolism-secretion coupling and decreased beta cell mass, attributed to excessive beta cell apoptosis. Here, we investigated the link between energy stress and apoptosis activation following HNF1A inactivation. This study employed single cell fluorescent microscopy, flow cytometry, gene expression analysis, and gene silencing to study the effects of overexpression of dominant-negative (DN)-HNF1A expression on cellular bioenergetics and apoptosis in INS-1 cells. Induction of DN-HNF1A expression led to reduced ATP levels and diminished the bioenergetic response to glucose. This was coupled with activation of the bioenergetic stress sensor AMP-activated protein kinase (AMPK), which preceded the onset of apoptosis. Pharmacological activation of AMPK using aminoimidazole carboxamide ribonucleotide (AICAR) was sufficient to induce apoptosis in naive cells. Conversely, inhibition of AMPK with compound C or AMPK␣ gene silencing protected against DN-HNF1A-induced apoptosis. Interestingly, AMPK mediated the induction of the pro-apoptotic Bcl-2 homology domain-3-only protein Bmf (Bcl-2-modifying factor). Bmf expression was also elevated in islets of DN-HNF1A transgenic mice. Furthermore, knockdown of Bmf expression in INS-1 cells using siRNA was sufficient to protect against DN-HNF1A-induced apoptosis. Our study suggests that overexpression of DN-HNF1A induces bioenergetic stress and activation of AMPK. This in turn mediates the transcriptional activation of the pro-apoptotic Bcl-2-homology protein BMF, coupling prolonged energy stress to apoptosis activation.

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Section: Expression Of Dn-hnf1a Causes Bioenergetic Dysfunction Inmentioning

confidence: 61%

mentioning

confidence: 96%

Section: Expression Of Dn-hnf1a Causes Bioenergetic Dysfunction Inmentioning

confidence: 99%

mentioning

confidence: 99%

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AMP-activated Protein Kinase Mediates Apoptosis in Response to Bioenergetic Stress through Activation of the Pro-apoptotic Bcl-2 Homology Domain-3-only Protein BMF

Kilbride

Farrelly

Bonner

et al. 2010

Journal of Biological Chemistry

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“…MS analysis on an Applied Biosystems API4000 QTrap interfaced to a Shimadzu HPLC, as previously described (56).…”

Section: Assessment Of Contractile Dysfunction In Vivomentioning

confidence: 99%

Urocortin 2 autocrine/paracrine and pharmacologic effects to activate AMP-activated protein kinase in the heart

Qi²,

Cheng

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

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Urocortin 2 (Ucn2), a peptide of the corticotropin-releasing factor (CRF) family, binds with high affinity to type 2 CRF receptors (CRFR2) on cardiomyocytes and confers protection against ischemia/reperfusion. The mechanisms by which the Ucn2-CRFR2 axis mitigates against ischemia/reperfusion injury remain incompletely delineated. Activation of AMP-activated protein kinase (AMPK) also limits cardiac damage during ischemia/reperfusion. AMPK is classically activated by alterations in cellular energetics; however, hormones, cytokines, and additional autocrine/paracrine factors also modulate its activity. We examined the effects of both the endogenous cardiac Ucn2 autocrine/paracrine pathway and Ucn2 treatment on AMPK regulation. Ucn2 treatment increased AMPK activation and downstream acetyl-CoA carboxylase phosphorylation and glucose uptake in isolated heart muscles. These actions were blocked by the CRFR2 antagonist anti-sauvagine-30 and by a PKCe translocation-inhibitor peptide (eV1-2). Hypoxia-induced AMPK activation was also blunted in heart muscles by preincubation with either anti-sauvagine-30, a neutralizing anti-Ucn2 antibody, or eV1-2. Treatment with Ucn2 in vivo augmented ischemic AMPK activation and reduced myocardial injury and cardiac contractile dysfunction after regional ischemia/reperfusion in mice. Ucn2 also directly activated AMPK in ex vivo-perfused mouse hearts and diminished injury and contractile dysfunction during ischemia/reperfusion. Thus, both Ucn2 treatment and the endogenous cardiac Ucn2 autocrine/paracrine pathway activate AMPK signaling pathway, via a PKCe-dependent mechanism, defining a Ucn2-CRFR2-PKCe-AMPK pathway that mitigates against ischemia/reperfusion injury. metabolism | cardiac function

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Rapamycin protects against dominant negative-HNF1A-induced apoptosis in INS-1 cells

et al. 2011

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HNF1A-maturity onset diabetes of the young (HNF1A-MODY) is caused by mutations in Hnf1a gene encoding the transcription factor hepatocyte nuclear factor 1alpha (HNF1A). An increased rate of apoptosis has been associated with the decrease in beta-cell mass that is a hallmark of HNF1A-MODY and other forms of diabetes. In a cellular model of HNF1A-MODY, we have recently shown that signalling through mammalian target of rapamycin (mTOR) is decreased by the overexpression of a dominant-negative mutant of HNF1A (DN-HNF1A). mTOR is a protein kinase which has important roles in cell metabolism and growth, but also in cell survival, where it has been shown to be both protective and detrimental. Here, we show that pharmacological inhibition of mTOR activity with rapamycin protected INS-1 cells against DN-HNF1A-induced apoptosis. Rapamycin also prevented DN-HNF1A-induced activation of AMP-activated protein kinase (AMPK), an intracellular energy sensor which we have previously shown to mediate DN-HNF1A-induced apoptosis. Conversely, activation of mTOR with leucine potentiated DN-HNF1A-induced apoptosis. Gene silencing of raptor (regulatory associated protein of mTOR), a subunit of mTOR complex 1 (mTORC1), also conferred protection on INS-1 cells against DN-HNF1A-induced apoptosis, confirming that mTORC1 mediates the protective effect. The potential relevance of this effect with regards to the clinical use of rapamycin as an immunosuppressant in diabetics post-transplantation is discussed.

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Mitochondrial Dysfunction Contributes to Impaired Insulin Secretion in INS-1 Cells with Dominant-negative Mutations of HNF-1α and in HNF-1α-deficient Islets

Cited by 27 publications

References 40 publications

AMP-activated Protein Kinase Mediates Apoptosis in Response to Bioenergetic Stress through Activation of the Pro-apoptotic Bcl-2 Homology Domain-3-only Protein BMF

AMP-activated Protein Kinase Mediates Apoptosis in Response to Bioenergetic Stress through Activation of the Pro-apoptotic Bcl-2 Homology Domain-3-only Protein BMF

Urocortin 2 autocrine/paracrine and pharmacologic effects to activate AMP-activated protein kinase in the heart

Rapamycin protects against dominant negative-HNF1A-induced apoptosis in INS-1 cells

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