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. 2015 Jul 2;290(34):20934–20946. doi: 10.1074/jbc.M115.639237

FIGURE 4.

FIGURE 4.

Lkb1 deletion in β cells disrupts mitochondrial function. A, quantification of fluorescence intensity of TMRE (left) and MitoTracker Green (MTG, right) in islet cells from lox/lox and βLKB mice. Mice were 3 months of age, 2 months post-tamoxifen injection. The graph presents the mean of five mice in each genotype. 20–30 fields were imaged and averaged per mouse. The difference in fluorescence intensity of TMRE is translated to Δ 3 mV between lox/lox and βLKB cells. B, NAD(P)H production in response to 16.7 mm glucose. The plots represent the mean of NAD(P)H-derived fluorescence intensity in whole islets from lox/lox (n = 4) and βLKB (n = 4) mice measured by UV autofluorescence. Islets were perifused with 2.8 mm glucose for 12 min then with 16.7 mm for 15 min and back to 2.8 mm. Mice were 6 months old, 5 months post-tamoxifen injection. Right, mean of area under the curve (AUC) of the NAD(P)H plots. *, p < 0.05. C, cytosolic ATP/ADP ratio changes in islets in response to glucose. Glucose was changed during the experiment from 3 mm (G3) to 11 mm (G11). Note the significantly impaired response in βLKB1 islets. AU, arbitrary units. Data are from three wild type and three βLKB mice. D, amplitude of responsiveness presented in C. E, ATP/ADP ratio presented as % of islets responsive to glucose. *, p < 0.05. F, basal OCR measured by Seahorse XF24 analyzer in the presence of 2.8 mm glucose. ns, p > 0.05. G, OCR measured over time. Data are presented as -fold induction from basal OCR presented in F. Each plot represents the mean of 7 wells with 50 islets each from wild type (n = 3) or βLKB (n = 4) mice. Mice were 2.5 months old. Compounds injected at indicated times were glucose (20 mm), FCCP (1 μm), and rotenone plus antimycin A (R/A, 5 μm each). H, OCR in the presence of glutamine and leucine (Gln+Leu). Protocol is as described in G. Each plot represents the mean of 6 or 7 wells with 50 islets from wild type (n = 5) or βLKB (n = 4) mice. Mice were 6 month old. The assay were performed on Pdx1-CreERTM;LKB1 lox/lox mice, except for ATP measurements (C–E) that were performed on Ins1-Cre;LKB1lox/lox mice aged 10 weeks.