Soluble Adenylyl Cyclase Regulates Bile Salt-Induced Apoptosis in Human Cholangiocytes.
Soluble Adenylyl Cyclase Regulates Bile Salt-Induced Apoptosis in Human Cholangiocytes.
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DOI：
10.1002/hep.28550
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发表时间：
2016-08
期刊：
影响因子：
13.5
通讯作者：
Elferink, Ronald Oude
中科院分区：
文献类型：
--
作者：
Chang, Jung-Chin;Go, Simei;de Waart, Dirk R.;Munoz-Garrido, Patricia;Beuers, Ulrich;Paulusma, Coen C.;Elferink, Ronald Oude
阴离子交换器2（AE 2）是人类胆道系统中的主要碳酸氢盐分泌物，在原发性胆管炎中下调。AE 2产生一个“碳酸氢盐保护伞”，通过保持胆盐去质子化来保护胆管细胞免受胆盐的促凋亡作用。我们观察到，AE 2的敲低不仅使永生化H69人胆管细胞对胆盐诱导的凋亡（BSIA）敏感，而且使依托泊苷诱导的凋亡敏感。由于依托泊苷的毒性不依赖于pH值，因此AE 2耗竭的胆管细胞对凋亡刺激物的敏感性可能存在更普遍的机制。我们发现，AE 2缺乏导致细胞内碳酸氢盐积累和可溶性腺苷酸环化酶（sAC），进化保守的碳酸氢盐传感器的表达和活性增加。因此，我们假设sAC调节BSIA。以H69胆管细胞和原代小鼠胆管细胞为模型。sAC特异性抑制剂KH 7不仅逆转了AE 2耗尽的H69胆管细胞对BSIA的致敏作用，甚至完全预防了BSIA。四环素诱导的短发夹RNA敲低sAC也可预防BSIA。此外，sAC抑制逆转了BSIA膜起泡、核浓缩和DNA片段化。此外，sAC抑制也防止了原代小鼠胆管细胞中的BSIA。从机制上讲，sAC抑制阻止了BSIA期间Thr 167处的Bax磷酸化和Bax的线粒体易位以及细胞色素c释放，但不能阻止c-Jun N-末端激酶活化。最后，BSIA在H69胆管细胞被抑制细胞内钙离子螯合，加剧毒胡萝卜素，和细胞外钙的去除不受影响。结论：BSIA受sAC调节，依赖于细胞内Ca 2+储存，并由内源性凋亡途径介导;原发性胆管炎中AE 2的下调通过激活sAC使胆管细胞对凋亡损伤敏感，这可能在疾病发病机制中起关键作用。（肝病学2016;64：522 - 534）
Anion exchanger 2 (AE2), the principal bicarbonate secretor in the human biliary tree, is down‐regulated in primary biliary cholangitis. AE2 creates a “bicarbonate umbrella” that protects cholangiocytes from the proapoptotic effects of bile salts by maintaining them deprotonated. We observed that knockdown of AE2 sensitized immortalized H69 human cholangiocytes to not only bile salt‐induced apoptosis (BSIA) but also etoposide‐induced apoptosis. Because the toxicity of etoposide is pH‐independent, there could be a more general mechanism for sensitization of AE2‐depleted cholangiocytes to apoptotic stimuli. We found that AE2 deficiency led to intracellular bicarbonate accumulation and increased expression and activity of soluble adenylyl cyclase (sAC), an evolutionarily conserved bicarbonate sensor. Thus, we hypothesized that sAC regulates BSIA. H69 cholangiocytes and primary mouse cholangiocytes were used as models. The sAC‐specific inhibitor KH7 not only reversed sensitization to BSIA in AE2‐depleted H69 cholangiocytes but even completely prevented BSIA. sAC knockdown by tetracycline‐inducible short hairpin RNA also prevented BSIA. In addition, sAC inhibition reversed BSIA membrane blebbing, nuclear condensation, and DNA fragmentation. Furthermore, sAC inhibition also prevented BSIA in primary mouse cholangiocytes. Mechanistically, sAC inhibition prevented Bax phosphorylation at Thr167 and mitochondrial translocation of Bax and cytochrome c release but not c‐Jun N‐terminal kinase activation during BSIA. Finally, BSIA in H69 cholangiocytes was inhibited by intracellular Ca2+ chelation, aggravated by thapsigargin, and unaffected by removal of extracellular calcium. Conclusions: BSIA is regulated by sAC, depends on intracellular Ca2+ stores, and is mediated by the intrinsic apoptotic pathway; down‐regulation of AE2 in primary biliary cholangitis sensitizes cholangiocytes to apoptotic insults by activating sAC, which may play a crucial role in disease pathogenesis. (Hepatology 2016;64:522‐534)
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影响因子：
4.8
作者：
Litvin, TN;Kamenetsky, M;Levin, LR
通讯作者：
Levin, LR
影响因子：
29
作者：
Di Benedetto, Giulietta;Scalzotto, Elisa;Pozzan, Tullio
通讯作者：
Pozzan, Tullio
影响因子：
4.8
作者：
Kim, Bong-Jo;Ryu, Seung-Wook;Song, Byoung-Joon
通讯作者：
Song, Byoung-Joon
影响因子：
4.8
作者：
Mardones, Pablo;Medina, Juan F.;Elferink, Ronald P. J. Oude
通讯作者：
Elferink, Ronald P. J. Oude
影响因子：
4
作者：
Chang JC;Oude-Elferink RP
通讯作者：
Oude-Elferink RP