Fig. 7: BCR engagement and subsequent Lyn kinase activities counteracted BAFF-induced inflammasome activities and cell death. | Cell Death & Disease

Fig. 7: BCR engagement and subsequent Lyn kinase activities counteracted BAFF-induced inflammasome activities and cell death.

From: BAFF-driven NLRP3 inflammasome activation in B cells

Fig. 7: BCR engagement and subsequent Lyn kinase activities counteracted BAFF-induced inflammasome activities and cell death.The alternative text for this image may have been generated using AI.

a Maturation of caspase-1 and IL-1β was induced by BAFF, which was then attenuated by pre-incubation with anti-BCR antibodies (1 μg/ml; IgG for SU-DHL-4 cells, IgD + IgM for primary B cells), PP1 (10 μM), and/or MLR1023 (10 μM), in SU-DHL-4 cells transduced with empty vector (EV), comparing to that in stable LYN-KD cells. b Primary circulating B cells underwent the same treatments as in a, except that LYN expression was silenced using its siRNA. c The activities of the key signaling components in the BAFF–BAFFR axis was assessed using phospho-specific antibodies against SRC (Y416) and SRC(Y527) in BAFF-treated B cells. Blots were then stripped and reprobed with antibodies against total-SRC. Parental SU-DHL-4 and LYN-KD SU-DHL-4 cells were treated with BAFF alone or were pre-incubated with anti-BCR antibodies or MLR1023. d Primary B cells underwent treatments as in c. No experiments were performed in JM1 cells as they lack expression of mature BCR. e The representative images of untreated, BAFF-treated, BAFF/anti-BCR-treated, or BAFF/CASP1-KD-treated B cells stained for ASC specks/PI and DAPI were shown (×40 magnification). Scale bar, 30 μm. f The percentages of speck-positive and PI-positive cells. For each sample, 500 cells were counted, and ~20 images were analyzed. The data were calculated from three experiments. **p < 0.01, ***p < 0.001 (Student’s t-test). The results were presented as mean ± SEM. g Western blot analyses of full-length (FL) and cleaved GSDMD (p30) of cell lysates. Parental cells or CASP1-KD cells were left untreated or treated with BAFF with BAFF for 8-h in the absence or presence with anti-BCR antibodies. h A proposed model of NLRP3 inflammasome activation triggered by BAFF. As a control for the pharmacological inhibitors and activator, the equivalent volume of dimethyl sulfoxide (DMSO) was used. Rabbit anti-caspase-1, and anti-LYN antibodies were used to evaluate the KD effects (data not shown).

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