Figure 1.

Human vascular SMC, in contrast to EC, do not process recombinant IL-1β precursor. Recombinant IL-1α or IL-1β precursor (10 μg/ml, 15 μl) was incubated (37°C, 15 min) with processing buffer alone (pIL-1α/pIL-1β), culture supernatants (SN; 15 μl), or cell lysates (Ly; 2.5 × 10⁴ cells/μl, 15 μl) of unstimulated (−) or TNF-α–stimulated (+; 50 ng/ml) vascular SMC or unstimulated EC. The products were separated by SDS-PAGE and analyzed by Western blot with the respective antibody (IL-1β: Fib 3, 1:1,000; IL-1α: L4, 1:500). For control, the recombinant mature IL-1 isoforms (mIL-1α/ mIL-1β) were included. Similar results were obtained in four independent experiments.