title: Semaphorin3a inhibits ureteric bud branching morphogenesis.
abstract: Class 3 semaphorins are guidance proteins involved in axon pathfinding, vascular patterning and lung branching morphogenesis in the developing mouse embryo. Semaphorin3a (Sema3a) is expressed in renal epithelia throughout kidney development, including podocytes and ureteric bud cells. However, the role of Sema3a in ureteric bud branching is unknown. Here we demonstrate that Sema3a plays a role in patterning the ureteric bud tree in both metanephric organ cultures and Sema3a mutant mice. In vitro ureteric bud injection with Sema3a antisense morpholino resulted in increased branching, whereas recombinant SEMA3A inhibited ureteric bud branching and decreased the number of developing glomeruli. Additional studies revealed that SEMA3A effects on ureteric bud branching involve downregulation of glial cell-line derived neurotrophic factor (GDNF) signaling, competition with vascular endothelial growth factor A (VEGF-A) and decreased activity of Akt survival pathways. Deletion of Sema3a in mice is associated with increased ureteric bud branching, confirming its inhibitory role in vivo. Collectively, these data suggest that Sema3a is an endogenous antagonist of ureteric bud branching and hence, plays a role in patterning the renal collecting system as a negative regulator.
authors.affiliation: Department of Pediatrics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Forchheimer Building, Room 708, Bronx, NY 10461, USA. atufro@aecom.yu.edu
authors.forename: Alda
authors.initials: A
authors.lastname: Tufro
authors.forename: Jason
authors.initials: J
authors.lastname: Teichman
authors.forename: Craig
authors.initials: C
authors.lastname: Woda
authors.forename: Guillermo
authors.initials: G
authors.lastname: Villegas
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism; D001667:Binding, Competitive; D019521:Body Patterning; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D016376:Oligonucleotides, Antisense / Q000737:chemistry; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D040121:Semaphorin-3A / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction; D014513:Ureter / Q000196:embryology*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D051100:Glial Cell Line-Derived Neurotrophic Factor; D016376:Oligonucleotides, Antisense; D011994:Recombinant Proteins; C488217:Sema3a protein, mouse; D040121:Semaphorin-3A; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D051057:Proto-Oncogene Proteins c-akt