Agonistic signaling through NK1R in BMDCs prevents apoptosis. (A) Number of viable CD11c⁺ BMDCs recovered 24 hours after culture in different conditions. ***P < .001. Means (± SD) of 6 independent experiments are shown. (B,C) Morphological and nuclear characteristics of apoptosis by BMDCs harvested 24 hours after culture in different conditions. (B) Morphological analysis of apoptosis as evaluated by cytospins of CD11c⁺ BMDCs stained with Hema-3. (C) Nuclear analysis of apoptosis as determined by cytospins of CD11c⁺ BMDCs stained with the nuclear dye DAPI (left panels) or suspensions of CD11c⁺ BMDCs stained with TUNEL (right panels). Withdrawal of GM-CSF (GM) and IL-4 (Medium) induces apoptosis of BMDCs characterized by surface membrane blebs (B top right panel, *), nuclear breakage (B top panel, →), chromatin condensation, and DNA fragmentation (C top panels, arrows), ×500; scale bar equals 20 μm. (D) Quantification of apoptosis in CD11c⁺ BMDCs by FACS analysis of annexin V and PI labeling. Numbers in dot-plots represent percentage of cells. Signaling via NK1R with SarSP (10⁻⁹ mol/L) prevents apoptosis of BMDCs to a similar extent as signaling via CD40 or addition of GM and IL-4 (positive controls). Data are representative of 10 independent experiments.