Zhang Haibao, Xu Shan, He Dalin, Wang Xinyang, Zhu Guodong
Department of Urology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China.
Oncology Research Lab, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, Xi'an, China.
Front Pediatr. 2021 Dec 22;9:765255. doi: 10.3389/fped.2021.765255. eCollection 2021.
Sonic hedgehog (SHH) signaling is important in bladder development. Mice with defective hedgehog signaling develop bladder anomalies. Clinically, urinary tract malformations are reported in human fetuses and infants with mutations of SHH and related signaling pathway genes. Information on the expression of SHH and associated signaling genes in normal human bladder development is fragmentary. This study determined the temporal and spatial expression patterns of SHH signaling pathway components in human fetal bladders by immunohistochemistry (IHC). Twenty-four bladder specimens from 16 male and 8 female human fetuses aged 12- to 36-week (wk) were obtained from the First Affiliated Hospital of Xi'an Jiaotong University. The tissue slides were processed for IHC staining with SHH, Patched1 (PTC-1), Patched2 (PTC-2), Smoothened (SMO), GLI1 and proliferating cell nuclear antigen (PCNA). The expression levels of each gene were analyzed by semi-quantitative histological scoring system. High intensity of SHH and SMO expression was detected in developing bladder urothelial cells, with no staining in lamina propria (LP), but with minimal expression of SMO in differentiating smooth muscle (SM) layers. The spatial distribution pattern of PTC1 and GLI1 was more complex with minimal expression in the LP layer, moderate expression in the SM layer, and high expression in the urothelium. PTC2 expression was mainly localized in the urothelium and LP, but no expression in the SM layer. All of the SHH signaling components were detected in fetal bladder tissues throughout the development, with expression peaks at 12- and 23-wk, coinciding with high cell proliferation as indicated by PCNA staining in the cell nuclei of urothelium and SM. The autocrine SHH signaling in the developing urothelium, and paracrine SHH signaling in the developing smooth muscle layer, mediated by SMO, PTC-1 and GLI1 were demonstrated during human bladder development. Expression of SHH signaling components peaked at 12-and 23-wk. The first expression peak at 12-wk may relate to urothelium growth, SM induction, and dilation of the bladder cavity. The second expression peaked at 23-wk may relate to urothelium and SM layer differentiation.
音猬因子（SHH）信号通路在膀胱发育过程中起着重要作用。刺猬信号通路存在缺陷的小鼠会出现膀胱异常。临床上，有报道称人类胎儿和婴儿中存在SHH及相关信号通路基因突变时会出现尿路畸形。关于SHH及相关信号基因在正常人类膀胱发育过程中的表达信息尚不完整。本研究通过免疫组织化学（IHC）方法确定了SHH信号通路成分在人类胎儿膀胱中的时空表达模式。从西安交通大学第一附属医院获取了16例男性和8例女性、年龄在12至36周（wk）的24个胎儿膀胱标本。将组织切片进行免疫组织化学染色，检测SHH、patched1（PTC-1）、patched2（PTC-2）、 smoothened（SMO）、GLI1和增殖细胞核抗原（PCNA）。通过半定量组织学评分系统分析每个基因的表达水平。在发育中的膀胱尿路上皮细胞中检测到SHH和SMO的高表达，固有层（LP）无染色，但在分化中的平滑肌（SM）层中SMO表达最低。PTC1和GLI1的空间分布模式更为复杂，在LP层表达最低，在SM层中度表达，在尿路上皮中高表达。PTC2表达主要定位于尿路上皮和LP，但在SM层无表达。在整个发育过程中，所有SHH信号通路成分均在胎儿膀胱组织中被检测到，在12周和23周时表达达到峰值，这与尿路上皮和SM细胞核中PCNA染色所示的高细胞增殖相一致。在人类膀胱发育过程中，证实了发育中的尿路上皮中的自分泌SHH信号通路以及由SMO、PTC-1和GLI1介导的发育中的平滑肌层中的旁分泌SHH信号通路。SHH信号通路成分的表达在12周和23周时达到峰值。12周时的第一个表达峰值可能与尿路上皮生长、SM诱导和膀胱腔扩张有关。23周时的第二个表达峰值可能与尿路上皮和SM层分化有关。
