Journal: Diabetologia

Article Title: Presence of immunogenic alternatively spliced insulin gene product in human pancreatic delta cells

doi: 10.1007/s00125-023-05882-y

Figure Lengend Snippet: IDE is not expressed in delta cells and cleaves INS-splice. ( a ) Pancreatic IDE protein expression was determined by immunohistochemistry of human pancreas sections by staining for proinsulin (green), IDE (white) and somatostatin (red). IDE was expressed ubiquitously in the exocrine and endocrine pancreas except in delta cells. Scale bar, 10 μm. Nuclei were visualised by Hoechst staining (blue). ( b ) Co-localisation of IDE with insulin and IDE with somatostatin was quantified using MCC (QuPath). Thirty-six islets from six pancreas donors were analysed. Data are shown as mean ± SD and statistical analysis was performed using a paired two-tailed Student’s t test (*** p <0.001). ( c ) Coomassie staining of INS-splice after IDE cleavage assay. Absence or presence of IDE is indicated by − or +, respectively. Full-length recombinant INS-splice is 14 kDa. INS, insulin; M, protein marker; SST, somatostatin

Article Snippet: Recombinant alternatively spliced insulin product (INS-splice; 0.25 μg/μl) was incubated with recombinant human IDE (0.05 μg/μl, 2496-ZN; R&D Systems, USA) in cleavage buffer (50 mmol/l Tris, 1 mol/l NaCl, pH 7.5) at 37°C for 48 h, following the manufacturer’s recommendations.

Techniques: Expressing, Immunohistochemistry, Staining, Two Tailed Test, Cleavage Assay, Recombinant, Marker

Journal: Metabolism: clinical and experimental

Article Title: Hepatic insulin-degrading enzyme regulates glucose and insulin homeostasis in diet-induced obese mice

doi: 10.1016/j.metabol.2020.154352

Figure Lengend Snippet: Hepatic IDE gain-of-function improves glucose metabolism and insulin sensitivity in high-fat induced obesity. Four-week-old male C57BL/6J mice were fed a high-fat diet (HFD) for 4 weeks. Mice were then stratified by body weight and assigned randomly to two groups (n = 7–10 per group), and human Ide cDNA or control vector were delivered by adenovirus-mediated gene transfer to the liver of mice. Mice were maintained on the HFD for another 2 weeks (a total of 6 weeks on HFD), and glucose homeostasis was assessed at the time points indicated below. (A) Hepatic IDE levels (2-weeks after adenoviruses delivery). Upper panel : Representative samples have been used for the final arrangement of the figure. Lower panel : Quantification of the ratio of IDE vs. GAPDH in control (Ad.null) and IDE (Ad.IDE) vector treated mice. Data are mean ± SEM. n = 7–10 per group. * p value <0.05 vs. control-vector treated mice by Student’s t -test. In addition, glucose tolerance (1-week after adenovirus delivery) and insulin sensitivity (2-weeks after adenovirus delivery) were assessed in these mice. (B) IP-GTT and area under the curve (C). (D) IP-ITT, and area under the curve (E). HOMA index (F). Fasting (G) and non-fasting blood glucose (H). Body weight (I), food intake (J), and epididymal fat pad mass (K). Data are mean ± SEM. n = 7–10 per group. * p value <0.05 by Student’s t -test.

Article Snippet: Human Ide cDNA was purchased from ImaGenes GmbH (Berlin, Germany).

Techniques: Control, Plasmid Preparation