AUTHOR=Rieke Johanna Magdalena , Zhang Rong , Braun Doreen , Yilmaz Öznur , Japp Anna S. , Lopes Filipa M. , Pleschka Michael , Hilger Alina C. , Schneider Sophia , Newman William G. , Beaman Glenda M. , Nordenskjöld Agneta , Ebert Anne-Karoline , Promm Martin , Rösch Wolfgang H. , Stein Raimund , Hirsch Karin , Schäfer Frank-Mattias , Schmiedeke Eberhard , Boemers Thomas M. , Lacher Martin , Kluth Dietrich , Gosemann Jan-Hendrik , Anderberg Magnus , Barker Gillian , Holmdahl Gundela , Läckgren Göran , Keene David , Cervellione Raimondo M. , Giorgio Elisa , Di Grazia Massimo , Feitz Wouter F. J. , Marcelis Carlo L. M. , Van Rooij Iris A. L. M. , Bökenkamp Arend , Beckers Goedele M. A. , Keegan Catherine E. , Sharma Amit , Dakal Tikam Chand , Wittler Lars , Grote Phillip , Zwink Nadine , Jenetzky Ekkehart , Brusco Alfredo , Thiele Holger , Ludwig Michael , Schweizer Ulrich , Woolf Adrian S. , Odermatt Benjamin , Reutter Heiko TITLE=SLC20A1 Is Involved in Urinary Tract and Urorectal Development JOURNAL=Frontiers in Cell and Developmental Biology VOLUME=8 YEAR=2020 URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2020.00567 DOI=10.3389/fcell.2020.00567 ISSN=2296-634X ABSTRACT=

Previous studies in developing Xenopus and zebrafish reported that the phosphate transporter slc20a1a is expressed in pronephric kidneys. The recent identification of SLC20A1 as a monoallelic candidate gene for cloacal exstrophy further suggests its involvement in the urinary tract and urorectal development. However, little is known of the functional role of SLC20A1 in urinary tract development. Here, we investigated this using morpholino oligonucleotide knockdown of the zebrafish ortholog slc20a1a. This caused kidney cysts and malformations of the cloaca. Moreover, in morphants we demonstrated dysfunctional voiding and hindgut opening defects mimicking imperforate anus in human cloacal exstrophy. Furthermore, we performed immunohistochemistry of an unaffected 6-week-old human embryo and detected SLC20A1 in the urinary tract and the abdominal midline, structures implicated in the pathogenesis of cloacal exstrophy. Additionally, we resequenced SLC20A1 in 690 individuals with bladder exstrophy-epispadias complex (BEEC) including 84 individuals with cloacal exstrophy. We identified two additional monoallelic de novo variants. One was identified in a case-parent trio with classic bladder exstrophy, and one additional novel de novo variant was detected in an affected mother who transmitted this variant to her affected son. To study the potential cellular impact of SLC20A1 variants, we expressed them in HEK293 cells. Here, phosphate transport was not compromised, suggesting that it is not a disease mechanism. However, there was a tendency for lower levels of cleaved caspase-3, perhaps implicating apoptosis pathways in the disease. Our results suggest SLC20A1 is involved in urinary tract and urorectal development and implicate SLC20A1 as a disease-gene for BEEC.