LKB1 couples glucose metabolism to insulin secretion in mice.

Diabetologia (2015-04-16)
Accalia Fu, Karine Robitaille, Brandon Faubert, Courtney Reeks, Xiao-Qing Dai, Alexandre B Hardy, Krishana S Sankar, Svetlana Ogrel, Osama Y Al-Dirbashi, Jonathan V Rocheleau, Michael B Wheeler, Patrick E MacDonald, Russell Jones, Robert A Screaton
ABSTRACT

Precise regulation of insulin secretion by the pancreatic beta cell is essential for the maintenance of glucose homeostasis. Insulin secretory activity is initiated by the stepwise breakdown of ambient glucose to increase cellular ATP via glycolysis and mitochondrial respiration. Knockout of Lkb1, the gene encoding liver kinase B1 (LKB1) from the beta cell in mice enhances insulin secretory activity by an undefined mechanism. Here, we sought to determine the molecular basis for how deletion of Lkb1 promotes insulin secretion. To explore the role of LKB1 on individual steps in the insulin secretion pathway, we used mitochondrial functional analyses, electrophysiology and metabolic tracing coupled with by gas chromatography and mass spectrometry. Beta cells lacking LKB1 surprisingly display impaired mitochondrial metabolism and lower ATP levels following glucose stimulation, yet compensate for this by upregulating both uptake and synthesis of glutamine, leading to increased production of citrate. Furthermore, under low glucose conditions, Lkb1(-/-) beta cells fail to inhibit acetyl-CoA carboxylase 1 (ACC1), the rate-limiting enzyme in lipid synthesis, and consequently accumulate NEFA and display increased membrane excitability. Taken together, our data show that LKB1 plays a critical role in coupling glucose metabolism to insulin secretion, and factors in addition to ATP act as coupling intermediates between feeding cues and secretion. Our data suggest that beta cells lacking LKB1 could be used as a system to identify additional molecular events that connect metabolism to cellular excitation in the insulin secretion pathway.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Chloroform, anhydrous, ≥99%, contains 0.5-1.0% ethanol as stabilizer
Sigma-Aldrich
Chloroform, anhydrous, contains amylenes as stabilizer, ≥99%
Sigma-Aldrich
Tetramethylrhodamine ethyl ester perchlorate, suitable for fluorescence, ≥90% (HPCE)
Sigma-Aldrich
Chloroform, ≥99%, PCR Reagent, contains amylenes as stabilizer
Supelco
Chloroform, suitable for HPLC, ≥99.8%, contains 0.5-1.0% ethanol as stabilizer
Sigma-Aldrich
Chloroform, ACS reagent, ≥99.8%, contains 0.5-1.0% ethanol as stabilizer
Sigma-Aldrich
Chloroform, ACS reagent, ≥99.8%, contains amylenes as stabilizer
Supelco
Chloroform, suitable for HPLC, ≥99.8%

Social Media

LinkedIn icon
Twitter icon
Facebook Icon
Instagram Icon

MilliporeSigma

Research. Development. Production.

We are a leading supplier to the global Life Science industry with solutions and services for research, biotechnology development and production, and pharmaceutical drug therapy development and production.

© 2021 Merck KGaA, Darmstadt, Germany and/or its affiliates. All Rights Reserved.

Reproduction of any materials from the site is strictly forbidden without permission.