So Juhoon, Ningappa Mylarappa, Glessner Joseph, Min Jun, Ashokkumar Chethan, Ranganathan Sarangarajan, Higgs Brandon W, Li Dong, Sun Qing, Schmitt Lori, Biery Amy C, Dobrowolski Steven, Trautz Christine, Fuhrman Leah, Schwartz Molly Christine, Klena Nikolai Thomas, Fusco Joseph, Prasadan Krishna, Adenuga Morayooluwa, Mohamed Nada, Yan Qi, Chen Wei, Horne William, Dhawan Anil, Sharif Khalid, Kelly Deirdre, Squires Robert H, Gittes George K, Hakonarson Hakon, Morell Victor, Lo Cecilia, Subramaniam Shankar, Shin Donghun, Sindhi Rakesh
Department of Developmental Biology, McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
Hillman Center for Pediatric Transplantation of the Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, United States.
Front Physiol. 2020 Oct 30;11:538701. doi: 10.3389/fphys.2020.538701. eCollection 2020.
BACKGROUND/AIMS: Infectious and genetic factors are invoked, respectively in isolated biliary atresia (BA), or syndromic BA, with major extrahepatic anomalies. However, isolated BA is also associated with minor extrahepatic gut and cardiovascular anomalies and multiple susceptibility genes, suggesting common origins.
We investigated novel susceptibility genes with genome-wide association, targeted sequencing and tissue staining in BA requiring liver transplantation, independent of BA subtype. Candidate gene effects on morphogenesis, developmental pathways, and ciliogenesis, which regulates left-right patterning were investigated with zebrafish knockdown and mouse knockout models, mouse airway cell cultures, and liver transcriptome analysis.
Single nucleotide polymorphisms in Mannosidase-1-α-2 () were significantly associated with BA and with other polymorphisms known to affect expression but were not differentially enriched in either BA subtype. In zebrafish embryos, knockdown caused poor biliary network formation, ciliary dysgenesis in Kupffer's vesicle, cardiac and liver heterotaxy, and dysregulated and other developmental genes. Suboptimal knockdown synergized with suboptimal EGFR signaling or suboptimal knockdown of the EGFR pathway gene, adenosine-ribosylation-factor-6, which had minimal effects individually, to reproduce biliary defects but not heterotaxy. In cultured mouse airway epithelium, knockdown arrested ciliary development and motility. mice, which experience respiratory failure, also demonstrated portal and bile ductular inflammation. Human BA liver and liver exhibited reduced expression and dysregulated ciliary genes, known to cause multisystem human laterality defects.
BA requiring transplantation associates with sequence variants in . regulates laterality, in addition to hepatobiliary morphogenesis, by regulating ciliogenesis in zebrafish and mice, providing a novel developmental basis for multisystem defects in BA.
背景/目的：感染因素和遗传因素分别被认为与孤立性胆道闭锁（BA）或伴有主要肝外异常的综合征性BA有关。然而，孤立性BA也与轻微的肝外肠道和心血管异常以及多个易感基因有关，提示存在共同的起源。
我们在需要肝移植的BA患者中，不考虑BA亚型，通过全基因组关联研究、靶向测序和组织染色来研究新的易感基因。利用斑马鱼基因敲低模型、小鼠基因敲除模型、小鼠气道细胞培养和肝脏转录组分析，研究候选基因对形态发生、发育途径以及调节左右模式的纤毛发生的影响。
甘露糖苷酶-1-α-2（）中的单核苷酸多态性与BA以及已知影响表达的其他多态性显著相关，但在两种BA亚型中均未差异富集。在斑马鱼胚胎中，基因敲低导致胆管网络形成不良、库普弗小泡中的纤毛发育不全、心脏和肝脏异位以及和其他发育基因的失调。次优的基因敲低与次优的表皮生长因子（EGFR）信号传导或EGFR途径基因腺苷核糖基化因子-6的次优敲低协同作用，单独作用时影响极小，但能重现胆管缺陷但不能重现异位。在培养的小鼠气道上皮细胞中，基因敲低使纤毛发育和运动停滞。经历呼吸衰竭的小鼠也表现出门静脉和胆管炎症。人类BA肝脏和肝脏表现出表达降低和纤毛基因失调，已知这些基因会导致人类多系统偏侧性缺陷。
需要移植的BA与基因中的序列变异有关。通过调节斑马鱼和小鼠的纤毛发生，除了肝胆形态发生外，还调节偏侧性，为BA中的多系统缺陷提供了新的发育基础。
