Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
Hum Pathol. 2014 May;45(5):1057-64. doi: 10.1016/j.humpath.2014.01.002. Epub 2014 Jan 23.
Although physiologic jaundice of neonates is common, persistent neonatal cholestasis is life-threatening and has multiple etiologies. Among these etiologies, biliary atresia (BA) requires rapid diagnosis and treatment. In diagnosing BA, the surgical pathologist must recognize subtle histologic changes, often with only a small core liver biopsy. To aid in the differential diagnosis of neonatal cholestasis, we investigated Yes-associated protein (YAP), a regulator of organ size and bile duct development. We examined whether a YAP immunostain can highlight emerging hepatobiliary epithelium in BA (n = 28) versus other causes of persistent cholestasis (non-BA; n = 15) and thus serve as a useful diagnostic marker in persistent neonatal jaundice. We show significantly (P < .01) more high-grade (<2) fibrosis and ductular proliferation among BA versus non-BA cases. Likewise, there was significantly more high-grade (2-3/3) cytoplasmic and nuclear YAP staining in BA (97% and 89%) versus non-BA (20% and 13%). High-grade nuclear YAP staining was both sensitive (88%) and specific (87%) for the diagnosis of BA. In contrast to neonatal cholestasis, the differences in YAP localization in cholestatic/obstructed versus nonobstructed adult livers were not significant. Lastly, we found that pharmacologic inhibition of the YAP complex in both cholangiocyte and cholangiocarcinoma cell lines blocked compensatory bile duct proliferation, an early marker of BA that requires nuclear YAP expression, in a time- and dose-dependent manner. In summary, we show that YAP expression modulates both bile duct proliferation and liver damage/fibrosis while acting as a sensitive and specific marker in the differential diagnosis of persistent neonatal cholestasis.
尽管新生儿生理性黄疸很常见，但持续性新生儿胆汁淤积症具有生命威胁，且病因众多。其中，胆道闭锁（BA）需要快速诊断和治疗。在诊断 BA 时，外科病理学家必须识别细微的组织学变化，通常仅进行小的核心肝活检。为了帮助鉴别新生儿胆汁淤积症的病因，我们研究了 Yes 相关蛋白（YAP），这是一种调节器官大小和胆管发育的蛋白。我们研究了 YAP 免疫染色是否可以突出 BA（n = 28）与其他持续性胆汁淤积症（非 BA；n = 15）之间新出现的肝胆上皮细胞，从而作为持续性新生儿黄疸的有用诊断标志物。我们发现 BA 组的高级别（<2 级）纤维化和胆管增生显著高于非 BA 组（P <.01）。同样，BA 组的细胞质和核 YAP 染色的高级别（2-3/3 级）也显著高于非 BA 组（97%和 89% vs. 20%和 13%）。高级别核 YAP 染色对 BA 的诊断具有敏感性（88%）和特异性（87%）。与新生儿胆汁淤积症不同，在胆管扩张/阻塞与非阻塞的成人肝脏中，YAP 定位的差异并不显著。最后，我们发现，在胆管细胞和胆管癌细胞系中，YAP 复合物的药物抑制以时间和剂量依赖的方式阻断了代偿性胆管增生，这是 BA 的早期标志物，需要核 YAP 表达。总之，我们发现 YAP 表达调节胆管增生和肝损伤/纤维化，同时作为持续性新生儿胆汁淤积症鉴别诊断的敏感和特异性标志物。
