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