title: Overexpression of Robo2 causes defects in the recruitment of metanephric mesenchymal cells and ureteric bud branching morphogenesis.
abstract: Roundabout 2 (Robo2) is a member of the membrane protein receptor family. The chemorepulsive effect of Slit2-Robo2 signaling plays vital roles in nervous system development and neuron migration. Slit2-Robo2 signaling is also important for maintaining the normal morphogenesis of the kidney and urinary collecting system, especially for the branching of the ureteric bud (UB) at the proper site. Slit2 or Robo2 mouse mutants exhibit multilobular kidneys, multiple ureters, and dilatation of the ureter, renal pelvis, and collecting duct system, which lead to vesicoureteral reflux. To understand the effect of Robo2 on kidney development, we used microinjection and electroporation to overexpress GFP-Robo2 in an in vitro embryonic kidney model. Our results show reduced UB branching and decreased glomerular number after in vitro Robo2 overexpression in the embryonic kidneys. We found fewer metanephric mesenchymal (MM) cells surrounding the UB but no abnormal morphology in the branching epithelial UB. Meanwhile, no significant change in MM proliferation or apoptosis was observed. These findings indicate that Robo2 is involved in the development of embryonic kidneys and that the normal expression of Robo2 can help maintain proper UB branching and glomerular morphogenesis. Overexpression of Robo2 leads to reduced UB branching caused by fewer surrounding MM cells, but MM cell apoptosis is not involved in this effect. Our study demonstrates that overexpression of Robo2 by microinjection in embryonic kidneys is an effective approach to study the function of Robo2.
authors.affiliation: Institute of Nephrology, State Key Laboratory of Kidney Disease (2011DAV00088), The Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Jiayao
authors.initials: J
authors.lastname: Ji
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Li
authors.forename: Yuansheng
authors.initials: Y
authors.lastname: Xie
authors.forename: Xueguang
authors.initials: X
authors.lastname: Zhang
authors.forename: Shaoyuan
authors.initials: S
authors.lastname: Cui
authors.forename: Suozhu
authors.initials: S
authors.lastname: Shi
authors.forename: Xiangmei
authors.initials: X
authors.lastname: Chen
mesh_terms: D000818:Animals; D017209:Apoptosis; D015820:Cadherins / Q000378:metabolism; D049109:Cell Proliferation; D018274:Electroporation; D007668:Kidney / Q000196:embryology; D007678:Kidney Glomerulus / Q000196:embryology; D008648:Mesoderm / Q000166:cytology* / Q000196:embryology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008845:Microinjections; D009024:Morphogenesis; D011971:Receptors, Immunologic / Q000096:biosynthesis* / Q000235:genetics; D014513:Ureter / Q000196:embryology* / Q000378:metabolism; D000097905:Roundabout Proteins
chemical_list: D015820:Cadherins; D011971:Receptors, Immunologic; C498888:Robo2 protein, mouse; D000097905:Roundabout Proteins