The primary objective of this project is to study disease mechanisms of newly identified genes for vesicoureteral reflux (VUR) using a combined in vivo and in vitro molecular genetics approach. VUR is one of the commonest congenital anomalies of the kidney and urinary tract (CAKUT) in children. It is characterized by reflux of urine from the bladder into the kidney and is commonly associated with abnormal renal tract development, including defects in ureteric bud (UB) outgrowth and ureterovesical junction formation, and abnormal ureter development and peristalsis. Despite the high incidence of VUR in children, the genetic/molecular basis and disease mechanisms of VUR remain largely unclear. ROBO2 is one of few VUR/CAKUT genes that cause VUR phenotype in both human and animal model with many identified disease- causing mutations. Our recent studies show that mutations in SLIT2 and SRGAP1, two components of ROBO2 signaling pathway, can also result in CAKUT phenotype. However, the pathogenesis of SLIT2-ROBO2 signaling in VUR and CAKUT patients remain unclear. To test disease mechanisms and establish causality for ROBO2 mutations in human VUR, we will perform functional studies to determine if ROBO2 mutations disrupt interactions with known CAKUT-causing genes/proteins and if ROBO2 mutation knock-in mice also develop CAKUT and VUR phenotype (Aim 1). Since a recent study shows that ROBO2 controls UB outgrowth by regulating the separation of early Wolffian duct and nephrogenic cord, we will also study SLIT2 and SRGAP1 knockout mice to determine if they also play a role in early Wolffian duct and nephrogenic cord separation and if loss of SLIT2-ROBO2 signaling causes renal mesenchymal cell adhesion and migration defects (Aim 2). ZEB2 is a transcription factor that plays an import role in maintaining mesenchymal cells and promotes epithelial-mesenchymal transition via a BMP/SMAD/ZEB signaling network during development. Because we have recently found that deletion of ZEB2 gene can result in VUR phenotype in patients and ureter specific knockout of Zeb2 in mice causes abnormal ureter development, hydroureter, hydronephrosis and renal failure, we will also examine the role of Zeb2 in early ureteral mesenchymal cell development and determine if loss of Zeb2 in mouse ureter disrupts ureteral smooth muscle function and peristaltic machinery leading to VUR (Aim 3). Collectively, this research proposal will help us to understand disease mechanisms of newly identified VUR genes and define their molecular functions during urinary tract development. Results from this project will provide new knowledge in the molecular pathogenesis of VUR and assist us to identify novel therapeutic strategies for human VUR.

Public Health Relevance

Vesicoureteral reflux (VUR) is a common birth defect in childhood that causes substantial morbidity and mortality and originates from abnormal urinary tract development. A significant proportion of patients with VUR will develop progressive chronic kidney disease and eventually kidney failure, and will need dialysis or kidney transplantation for survival. Understanding the disease mechanisms of VUR genes will provide novel approaches to detect patients at risk and identify new therapeutic strategies.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK078226-06A1
Application #
9174929
Study Section
Special Emphasis Panel (ZRG1-DKUS-G (90)S)
Program Officer
Hoshizaki, Deborah K
Project Start
2008-08-01
Project End
2019-06-30
Budget Start
2016-09-15
Budget End
2017-06-30
Support Year
6
Fiscal Year
2016
Total Cost
$261,000
Indirect Cost
$111,000
Name
Boston Medical Center
Department
Type
DUNS #
005492160
City
Boston
State
MA
Country
United States
Zip Code
02118
van der Ven, Amelie T; Connaughton, Dervla M; Ityel, Hadas et al. (2018) Whole-Exome Sequencing Identifies Causative Mutations in Families with Congenital Anomalies of the Kidney and Urinary Tract. J Am Soc Nephrol 29:2348-2361
Tumelty, Kathleen E; Higginson-Scott, Nathan; Fan, Xueping et al. (2018) Identification of direct negative cross-talk between the SLIT2 and bone morphogenetic protein-Gremlin signaling pathways. J Biol Chem 293:3039-3055
van der Ven, Amelie T; Kobbe, Birgit; Kohl, Stefan et al. (2018) A homozygous missense variant in VWA2, encoding an interactor of the Fraser-complex, in a patient with vesicoureteral reflux. PLoS One 13:e0191224
Vivante, Asaf; Mann, Nina; Yonath, Hagith et al. (2017) A Dominant Mutation in Nuclear Receptor Interacting Protein 1 Causes Urinary Tract Malformations via Dysregulation of Retinoic Acid Signaling. J Am Soc Nephrol 28:2364-2376
Havasi, Andrea; Lu, Weining; Cohen, Herbert T et al. (2017) Blocking peptides and molecular mimicry as treatment for kidney disease. Am J Physiol Renal Physiol 312:F1016-F1025
Gore, Bryan B; Miller, Samara M; Jo, Yong Sang et al. (2017) Roundabout receptor 2 maintains inhibitory control of the adult midbrain. Elife 6:
Rasouly, Hila Milo; Kumar, Sudhir; Chan, Stefanie et al. (2016) Loss of Zeb2 in mesenchyme-derived nephrons causes primary glomerulocystic disease. Kidney Int 90:1262-1273
Fan, Xueping; Yang, Hongying; Kumar, Sudhir et al. (2016) SLIT2/ROBO2 signaling pathway inhibits nonmuscle myosin IIA activity and destabilizes kidney podocyte adhesion. JCI Insight 1:e86934
Vivante, Asaf; Kleppa, Marc-Jens; Schulz, Julian et al. (2015) Mutations in TBX18 Cause Dominant Urinary Tract Malformations via Transcriptional Dysregulation of Ureter Development. Am J Hum Genet 97:291-301
Hwang, Daw-Yang; Kohl, Stefan; Fan, Xueping et al. (2015) Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 confer risk for congenital anomalies of the kidney and urinary tract. Hum Genet 134:905-16

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