A novel high-affinity peptide antagonist to the insulin receptor

Schäffer, Lauge; Brand, Christian; Hansen, Bent; Ribel, Ulla; Shaw, Andrew; Slaaby, Rita; Sturis, Jeppe

doi:10.1016/j.bbrc.2008.08.151

Cited by 139 publications

(170 citation statements)

References 6 publications

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“…A lack of detectable responses to exogenous insulin could also be caused by endogenous insulin occupying the insulin receptor. Thus, even under non-stimulatory conditions for mouse beta cells, the basal rates of insulin release measured in our experiments produced extracellular concentrations of 1 to 2 nmol/l in the incubation medium, more than sufficient to ensure occupation of the insulin receptor, whose IC 50 is about 20 to 30 pmol/l [41]. However, the lack of effect of endogenous insulin on somatostatin secretion was consistent with the lack of effect on glucose-induced somatostatin release of two pharmacological strategies to block intraislet insulin signalling.…”

Section: Discussionmentioning

confidence: 72%

Delta cell secretory responses to insulin secretagogues are not mediated indirectly by insulin

et al. 2012

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Aims/hypothesis Somatostatin from islet delta cells inhibits insulin and glucagon secretion, but knowledge of the regulation of pancreatic somatostatin release is limited. Some insulin secretagogues stimulate somatostatin secretion, and here we investigated whether delta cell secretory responses are indirectly regulated in a paracrine manner by insulin released from beta cells. Methods Hormone release from static incubations of primary mouse islets or somatostatin-secreting TGP52 cells was measured by RIA. mRNA expression was assessed by RT-PCR. Results Glucose and a range of other physiological and pharmacological agents stimulated insulin and somatostatin release, and insulin receptor mRNA was expressed in islets, MIN6 beta cells and TGP52 cells. However, exogenous insulin did not modulate basal or glucose-induced somatostatin secretion from islets, nor did pre-incubation with an antibody against the insulin receptor or with the insulin receptor tyrosine kinase inhibitor, HNMPA(AM) 3 . Glucose and tolbutamide stimulated somatostatin release from TGP52 cells, whereas a range of receptor-operating agents had no effect, the latter being consistent with a lack of corresponding receptor mRNA expression in these cells. Parasympathetic activation stimulated insulin, but inhibited somatostatin release from mouse islets in accordance with differences in muscarinic receptor mRNA expression in islets, MIN6 and TGP52 cells. The inhibitory effect on somatostatin secretion was reversed by pertussis toxin or the muscarinic receptor 2 antagonist, methoctramine. Conclusions/interpretations A number of insulin secretagogues have analogous effects on insulin and somatostatin release, but this similarity of response is not mediated by an indirect, paracrine action of insulin on delta cells.

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Section: Discussionmentioning

confidence: 72%

Delta cell secretory responses to insulin secretagogues are not mediated indirectly by insulin

et al. 2012

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“…1E). To address whether the stimulatory action of insulin was specifically mediated by IR, TRPM6-expressing HEK293T cells were incubated with 10 nM of S961, a specific IR antagonist (16). A subsaturating concentration of insulin (0.9 nM) was applied to minimize ligand competition between insulin and the antagonist.…”

Section: Resultsmentioning

confidence: 99%

Loss of insulin-induced activation of TRPM6 magnesium channels results in impaired glucose tolerance during pregnancy

Nair

Hocher

Verkaart

et al. 2012

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

126

137

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Hypomagnesemia affects insulin resistance and is a risk factor for diabetes mellitus type 2 (DM2) and gestational diabetes mellitus (GDM). Two single nucleotide polymorphisms (SNPs) in the epithelial magnesium channel TRPM6 (V 1393 I, K 1584 E) were predicted to confer susceptibility for DM2. Here, we show using patch clamp analysis and total internal reflection fluorescence microscopy, that insulin stimulates TRPM6 activity via a phosphoinositide 3-kinase and Rac1-mediated elevation of cell surface expression of TRPM6. Interestingly, insulin failed to activate the genetic variants TRPM6 (V 1393 I) and TRPM6(K 1584 E), which is likely due to the inability of the insulin signaling pathway to phosphorylate TRPM6(T 1391 ) and TRPM6(S 1583 ). Moreover, by measuring total glycosylated hemoglobin (TGH) in 997 pregnant women as a measure of glucose control, we demonstrate that TRPM6(V 1393 I) and TRPM6(K 1584 E) are associated with higher TGH and confer a higher likelihood of developing GDM. The impaired response of TRPM6(V 1393 I) and TRPM6(K 1584 E) to insulin represents a unique molecular pathway leading to GDM where the defect is located in TRPM6. G estational diabetes mellitus (GDM) is a condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy. Babies born to mothers with GDM are typically at increased risk of large for gestational age (LGA), low blood sugar, and jaundice (1). Women with GDM are at a higher risk for preeclampsia and Caesarean section (1) as well as developing diabetes mellitus type 2 (DM2) later in life (2). GDM affects 3-10% of pregnancies, depending on the population studied. No specific cause has been identified, but it is believed that in particular sex hormones (i.e., estrogen, progesterone, prolactin) produced during pregnancy increases a woman's resistance to insulin, resulting in impaired glucose tolerance (1, 3). Moreover, pregnant women are prone to lose magnesium (Mg 2+ ). Bardicef et al. (4) demonstrated that pregnancy itself is a condition of intracellular Mg 2+ depletion. This depletion was more pronounced in women affected by GDM. The elevation in female hormones as well as Mg 2+ deficiency during pregnancy impairs insulin sensitivity and these disturbances may even act synergistically.There is growing evidence suggesting that Mg 2+ deficiency is a significant risk factor for the development of insulin resistance and subsequently hypertension and DM2 (5-8), but the underlying molecular mechanism is unknown. The first evidence suggesting a direct connection between Mg 2+ deficiency and the occurrence of metabolic diseases came from the identification of a monogenic disease primarily characterized by significant hypomagnesemia that was caused by a mutation in a mitochondrial tRNA (9). Moreover, in a recent genome-wide association (GWA) study, it was demonstrated that certain SNPs nominally associated with hypomagnesemia also correlate with fasting glucose levels, again supporting the hypothesis of a direct link between Mg 2+ a...

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“…S961 was expressed in Escherichia coli as a fusion protein with an affinity tag and had the peptide sequence GSLDESFYDWFERQLGGGSGGSSLEEEWAQIQCEVWGRGCPSY with a disulfide bridge connecting the 2 cysteine residues (a gift from Novo Nordisk, Denmark) 18. We infused S961 dissolved in normal saline for 7 days at a rate of 12 μg/kg per hour via osmotic mini‐pumps (Alzet, Palo Alto, CA) implanted subcutaneously in male New Zealand White rabbits, weighing 2.2 to 2.6 kg while they were under general anesthesia.…”

Section: Methodsmentioning

confidence: 99%

“…The prevalence of type 2 diabetes is substantially higher than type 1, driven by the epidemics of obesity and insulin resistance,16 and is alarmingly on the rise with vascular pathophysiology being the major cause of morbidity and mortality. Since both disruption in insulin signaling17 and hyperglycemia16 are key pathophysiological mechanisms of type 2 diabetes–induced vascular dysfunction, we induced a hyperglycemic state by competitively blocking insulin signaling through continuous infusion of S961, a high‐affinity peptide inhibitor of insulin receptor 18. Moreover, pharmacology and physiological effects of the β 3 ARs in the cardiovascular system are highly species‐dependent, and since rabbits provide a relevant model for human β 3 AR,19 we characterized the metabolic and biochemical profile of S961‐induced hyperglycemia in rabbits.…”

Section: Introductionmentioning

confidence: 99%

β3 Adrenergic Stimulation Restores Nitric Oxide/Redox Balance and Enhances Endothelial Function in Hyperglycemia

Galougahi

Liu

García

et al. 2016

JAHA

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BackgroundPerturbed balance between NO and O2 •−. (ie, NO/redox imbalance) is central in the pathobiology of diabetes‐induced vascular dysfunction. We examined whether stimulation of β3 adrenergic receptors (β3 ARs), coupled to endothelial nitric oxide synthase (eNOS) activation, would re‐establish NO/redox balance, relieve oxidative inhibition of the membrane proteins eNOS and Na+‐K+ (NK) pump, and improve vascular function in a new animal model of hyperglycemia.Methods and ResultsWe established hyperglycemia in male White New Zealand rabbits by infusion of S961, a competitive high‐affinity peptide inhibitor of the insulin receptor. Hyperglycemia impaired endothelium‐dependent vasorelaxation by “uncoupling” of eNOS via glutathionylation (eNOS‐GSS) that was dependent on NADPH oxidase activity. Accordingly, NO levels were lower while O2 •− levels were higher in hyperglycemic rabbits. Infusion of the β3 AR agonist CL316243 (CL) decreased eNOS‐GSS, reduced O2 •−, restored NO levels, and improved endothelium‐dependent relaxation. CL decreased hyperglycemia‐induced NADPH oxidase activation as suggested by co‐immunoprecipitation experiments, and it increased eNOS co‐immunoprecipitation with glutaredoxin‐1, which may reflect promotion of eNOS de‐glutathionylation by CL. Moreover, CL reversed hyperglycemia‐induced glutathionylation of the β1 NK pump subunit that causes NK pump inhibition, and improved K+‐induced vasorelaxation that reflects enhancement in NK pump activity. Lastly, eNOS‐GSS was higher in vessels of diabetic patients and was reduced by CL, suggesting potential significance of the experimental findings in human diabetes.Conclusionsβ3 AR activation restored NO/redox balance and improved endothelial function in hyperglycemia. β3 AR agonists may confer protection against diabetes‐induced vascular dysfunction.

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A novel high-affinity peptide antagonist to the insulin receptor

Cited by 139 publications

References 6 publications

Delta cell secretory responses to insulin secretagogues are not mediated indirectly by insulin

Delta cell secretory responses to insulin secretagogues are not mediated indirectly by insulin

Loss of insulin-induced activation of TRPM6 magnesium channels results in impaired glucose tolerance during pregnancy

β3 Adrenergic Stimulation Restores Nitric Oxide/Redox Balance and Enhances Endothelial Function in Hyperglycemia

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