Fig. 7.

Effects of hTrx1 on macrophage migration towards pancreatic islets. Cell migration assays were performed with primary murine macrophages cultured for 48 h in transwell plates using pancreatic islet culture medium as chemotactic stimulus in the presence or absence of reduced hTrx1 (final concentration 30, 60, 90 μg/ml), calcein-labelled migrated cells were counted. After 48 h of culture, islets were collected and washed three times with serum-free CMRL 1066 (PAA, Pasching, Austria). They were subsequently cultured for 48 h in serum-free CMRL 1066 supplemented with 2,5 mM l-Glutamine, 1 mM sodium pyruvate, 2 mg/ml glucose solution, 10 mM nicotinamide, Penicillin-Streptomycin and 200 mg Ciprofloxacin. The supernatant was collected for migration assay. As negative control, culture medium without islets was used. In addition, cells moving towards the islets' supernatant in the presence of 90 μg/ml denatured Trx1 (dhTrx1), redox-inactive hTrx1 C32S (C32S), or hTrx1 with 100 μM Polymyxin B were analyzed. The presence of 60 and 90 μg/ml hTrx1 significantly inhibited macrophage migration in contrast to dhTrx1 and C32S, which had no effect. Addition of Polymyxin B did not affect migration, ruling out LPS-mediated effects. ***p < 0.0001 (one-way ANOVA), n = 6.