Akifusa S, Ohguchi M, Koseki T, Nara K, Semba I, Yamato K, Okahashi N, Merino R, Núñez G, Hanada N, Takehara T, Nishihara T
Department of Oral Science, National Institute of Infectious Diseases, Tokyo, Japan.
Exp Cell Res. 1998 Jan 10;238(1):82-9. doi: 10.1006/excr.1997.3848.
We have previously demonstrated that cell death of WEHI-231 cells induced by specific inhibitors of vacuolar type H(+)-ATPase (V-ATPase) occurs through apoptosis. CD40 is involved in regulating activation, differentiation, and apoptosis of B cells. Here we show that the CD40 ligation rescues WEHI-231 cells from apoptotic cell death induced by a specific V-ATPase inhibitor, concanamycin A. CD40 signaling with anti-CD40 antibody resulted in the induction of Bcl-2 and Bcl-XL proteins in WEHI-231 cells. Constitutive expression of Bcl-2 but not Bcl-XL inhibited concanamycin A-induced apoptosis. These findings suggest that the expression of Bcl-2 mediated through CD40 signaling rescues the apoptotic cell death induced by blockade of V-ATPase. Interestingly, the acidification of intracellular acidic compartments was completely inhibited when WEHI-231 cells were cultured with concanamycin A, even in the presence of anti-CD40 antibody. In addition, apoptosis in WEHI-231 cells induced by concanamycin A was strongly suppressed when cultured with imidazole, a cell-permeable base, suggesting that apoptosis induced by concanamycin A is preceded by intraacidification.
我们之前已经证明，液泡型H(+)-ATP酶（V-ATP酶）的特异性抑制剂诱导的WEHI-231细胞死亡是通过凋亡发生的。CD40参与调节B细胞的激活、分化和凋亡。在此我们表明，CD40连接可使WEHI-231细胞从特异性V-ATP酶抑制剂 concanamycin A诱导的凋亡性细胞死亡中获救。用抗CD40抗体进行CD40信号传导导致WEHI-231细胞中Bcl-2和Bcl-XL蛋白的诱导。Bcl-2而非Bcl-XL的组成型表达抑制了concanamycin A诱导的凋亡。这些发现表明，通过CD40信号传导介导的Bcl-2表达可使由V-ATP酶阻断诱导的凋亡性细胞死亡获救。有趣的是，当WEHI-231细胞用concanamycin A培养时，即使存在抗CD40抗体，细胞内酸性区室的酸化也被完全抑制。此外，当用咪唑（一种可透过细胞的碱）培养时，concanamycin A诱导的WEHI-231细胞凋亡被强烈抑制，这表明concanamycin A诱导的凋亡之前存在细胞内酸化。
