Expression of DPP6 in human islets and EndoC-βH1 cells and other tissues evaluated by qPCR and histology. (A) Quantitative RT-PCR (qPCR) of DPP6 mRNA expression (detecting a shared sequence among all DPP6 splice variants) in EndoC-βH1 cells (n = 5) and human pancreatic islets (n = 4) that were exposed or not to cytokines (IL-1β + IFN-γ) for 48 h, as compared to pancreatic exocrine tissue (n = 6), two exocrine cell lines (Capan-2 (n = 3) and PANC (n = 3)), and 14 other non-pathological human tissues (n = 1). (B) Immunoblot of EndoC-βH1 cells under control conditions or following a 48h exposure to cytokines (IL-1β and IFN-γ), with alpha-tubulin as a reference protein. A representative figure is shown at the top and densitometric analysis at the bottom (n = 5), this figure displays a cropped blot, the full-length version is included in supplementary figure 8; (C–F) Immunocytochemistry of EndoC-βH1 cells. (C) An overlay with cells stained with an anti-DPP6 monoclonal antibody (mAb, red), co-stained for insulin (green) and Hoechst in blue. The separate channels are displayed in (D) insulin (green) and (E) DPP6 (red) (n = 3). The mostly surface localization of DPP6 (red) can be observed in (F) (n = 4), with blue signals indicating Hoechst staining. The negative staining control of EndoC-βH1 cells (without the DPP6 antibody) is placed in the top right corner of panel F. White scale bar represents 1 µm. RT-qPCR and the western blot data are presented as means ± SEM. Paired and unpaired two-way ANOVA (indicated with * and $, respectively), and unpaired one-way ANOVA (indicated with #) with Šídák correction for multiple comparisons; *, $ and # p ≤ 0.05 as indicated by bars.