Fig. 4

Blocking of N-cadherin but not of ICAM-1 decreased the MSC-enhanced insulin secretion. Antibodies against N-cadherin, ICAM-1, and isotype control were added to the culture of islets (islets), islets and MSC in coculture with cell–cell contact (islets MSC contact) and islets and MSC in culture without contact (islets MSC no contact) for 24 h prior to the insulin secretion assay. Cells were incubated in basal glucose (2.8 mM, white bars), high glucose concentration (16.7 mM, striped bars), and high glucose plus theophylline (16.7 and 5 mM, respectively, black bars) for 1 h. Data are presented as in Fig. 1. a Cells cultured alone and with the addition of 25 μg/ml anti-N-cadherin antibody and isotype control. b Cells cultured alone and with the addition of 25 μg/ml anti-ICAM-1 antibody. Values of secreted insulin are normalized to the total amount of insulin and expressed as fold increase where the basal level was set at 1. Human islets from four and three different donors used for N-cadherin and ICAM-1 blocking experiments, respectively. For each donor the experiment was performed in triplicate. Each graph represents mean ± SEM. Mann–Whitney test: *p < 0.05, **p < 0.01, ***p < 0.001