Age-dependent transition from islet insulin hypersecretion to hyposecretion in mice with the long QT-syndrome loss-of-function mutation Kcnq1-A340V

Anniek F Lubberding, Jinyi Zhang, Morten Lundh, Thomas Svava Nielsen, Mathilde S Søndergaard, Maria Villadsen, Emil Z. Skovhøj, Geke A Boer, Jakob B Hansen, Morten B Thomsen, Jonas T Treebak, Jens J Holst, Jørgen K Kanters, Thomas Mandrup-Poulsen, Thomas Jespersen, Brice Emanuelli, Signe S Torekov

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Abstract

Loss-of-function (LoF) mutations in KCNQ1, encoding the voltage-gated K+ channel Kv7.1, lead to long QT syndrome 1 (LQT1). LQT1 patients also present with post-prandial hyperinsulinemia and hypoglycaemia. In contrast, KCNQ1 polymorphisms are associated with diabetes, and LQTS patients have a higher prevalence of diabetes. We developed a mouse model with a LoF Kcnq1 mutation using CRISPR-Cas9 and hypothesized that this mouse model would display QT prolongation, increased glucose-stimulated insulin secretion and allow for interrogation of Kv7.1 function in islets. Mice were characterized by electrocardiography and oral glucose tolerance tests. Ex vivo, islet glucose-induced insulin release was measured, and beta-cell area quantified by immunohistochemistry. Homozygous mice had QT prolongation. Ex vivo, glucose-stimulated insulin release was increased in islets from homozygous mice at 12-14 weeks, while beta-cell area was reduced. Non-fasting blood glucose levels were decreased at this age. In follow-up studies 8-10 weeks later, beta-cell area was similar in all groups, while glucose-stimulated insulin secretion was now reduced in islets from hetero- and homozygous mice. Non-fasting blood glucose levels had normalized. These data suggest that Kv7.1 dysfunction is involved in a transition from hyper- to hyposecretion of insulin, potentially explaining the association with both hypoglycemia and hyperglycemia in LQT1 patients.

Original languageEnglish
Article number12253
JournalScientific Reports
Volume11
Issue number1
Number of pages14
ISSN2045-2322
DOIs
Publication statusPublished - 2021

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