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GDNF promotes tubulogenesis of GFRalpha1-expressing MDCK cells by Src-mediated phosphorylation of Met receptor tyrosine kinase.

Popsueva A, Poteryaev D, Arighi E, Meng X, Angers-Loustau A, Kaplan D, Saarma M, Sariola H - J. Cell Biol. (2003)

Bottom Line: However, GDNF does not immunoprecipite Met, making a direct interaction between GDNF and Met highly improbable.The GDNF-induced branching of MDCK cells requires Src activation, whereas the HGF-induced branching does not.Our data show a mechanism for the GDNF-induced branching morphogenesis in non-Ret signaling.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology, Institute of Biomedicine, University of Helsinki, FIN-00014 Helsinki, Finland.

ABSTRACT
Glial cell line-derived neurotrophic factor (GDNF) and hepatocyte growth factor (HGF) are multifunctional signaling molecules in embryogenesis. HGF binds to and activates Met receptor tyrosine kinase. The signaling receptor complex for GDNF typically includes both GDNF family receptor alpha1 (GFRalpha1) and Ret receptor tyrosine kinase. GDNF can also signal independently of Ret via GFRalpha1, although the mechanism has remained unclear. We now show that GDNF partially restores ureteric branching morphogenesis in ret-deficient mice with severe renal hypodysplasia. The mechanism of Ret-independent effect of GDNF was therefore studied by the MDCK cell model. In MDCK cells expressing GFRalpha1 but no Ret, GDNF stimulates branching but not chemotactic migration, whereas both branching and chemotaxis are promoted by GDNF in the cells coexpressing Ret and GFRalpha1, mimicking HGF/Met responses in wild-type MDCK cells. Indeed, GDNF induces Met phosphorylation in several ret-deficient/GFRalpha1-positive and GFRalpha1/Ret-coexpressing cell lines. However, GDNF does not immunoprecipite Met, making a direct interaction between GDNF and Met highly improbable. Met activation is mediated by Src family kinases. The GDNF-induced branching of MDCK cells requires Src activation, whereas the HGF-induced branching does not. Our data show a mechanism for the GDNF-induced branching morphogenesis in non-Ret signaling.

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Exogenous GDNF partially restores ureteric branching of ret-deficient kidneys. (A–D) Urogenital block explants including the Wolffian duct (wd), mesonephros (meso), and metanephros (meta) from E11 ret−/− (A and B), ret+/− (C), and ret+/+ (D) mouse embryos. The urogenital blocks from each embryo were separately cultured for 4 d, one side without GDNF (A, C and D) and the other one with 50 ng/ml of GDNF (B). The explants were fixed and immunolabeled as whole mounts with pan-cytokeratin antibodies. Bar, 200 μm. (E) The number of ureteric branches of ret−/−, ret+/−, and ret+/+ kidneys with or without GDNF supplementation. The results represent the means ± SEM. GDNF significantly increases ureteric branch number in ret−/− explants compared with the control media (P < 0.01).
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fig1: Exogenous GDNF partially restores ureteric branching of ret-deficient kidneys. (A–D) Urogenital block explants including the Wolffian duct (wd), mesonephros (meso), and metanephros (meta) from E11 ret−/− (A and B), ret+/− (C), and ret+/+ (D) mouse embryos. The urogenital blocks from each embryo were separately cultured for 4 d, one side without GDNF (A, C and D) and the other one with 50 ng/ml of GDNF (B). The explants were fixed and immunolabeled as whole mounts with pan-cytokeratin antibodies. Bar, 200 μm. (E) The number of ureteric branches of ret−/−, ret+/−, and ret+/+ kidneys with or without GDNF supplementation. The results represent the means ± SEM. GDNF significantly increases ureteric branch number in ret−/− explants compared with the control media (P < 0.01).

Mentions: To analyze the possible role of Ret-independent, GFRα1-mediated signaling in ureteric budding and branching during nephrogenesis, we tested the ability of exogenous GDNF to induce ureteric budding or sustain its branching in ret-deficient mice. Embryonic day (E)11 ret−/− urogenital blocks including kidney rudiments were cultured for 4 d without or with 50 ng/ml of GDNF (Fig. 1) . As expected, the ureteric buds of ret−/− mice did not branch or branched rudimentarily in the control media (Schuchardt et al., 1996). When the culture medium was supplemented with GDNF, the number of ureteric bud tips in the hypodysplastic kidneys of ret-deficient mice was increased but not to the level seen in wild-type kidneys (Fig. 1, B and D). Exogenous GDNF increased the number of ureteric bud tips in ret−/−, ret+/−, and wild-type kidney explants (Fig. 1 E). However, with or without exogenous GDNF the number of ret−/− urogenital explants completely lacking a ureteric bud remained the same (Table I). Thus, Ret-independent signaling by GDNF has an apparent role in the ureteric branching but may be less significant in the primary bud formation.


GDNF promotes tubulogenesis of GFRalpha1-expressing MDCK cells by Src-mediated phosphorylation of Met receptor tyrosine kinase.

Popsueva A, Poteryaev D, Arighi E, Meng X, Angers-Loustau A, Kaplan D, Saarma M, Sariola H - J. Cell Biol. (2003)

Exogenous GDNF partially restores ureteric branching of ret-deficient kidneys. (A–D) Urogenital block explants including the Wolffian duct (wd), mesonephros (meso), and metanephros (meta) from E11 ret−/− (A and B), ret+/− (C), and ret+/+ (D) mouse embryos. The urogenital blocks from each embryo were separately cultured for 4 d, one side without GDNF (A, C and D) and the other one with 50 ng/ml of GDNF (B). The explants were fixed and immunolabeled as whole mounts with pan-cytokeratin antibodies. Bar, 200 μm. (E) The number of ureteric branches of ret−/−, ret+/−, and ret+/+ kidneys with or without GDNF supplementation. The results represent the means ± SEM. GDNF significantly increases ureteric branch number in ret−/− explants compared with the control media (P < 0.01).
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2172872&req=5

fig1: Exogenous GDNF partially restores ureteric branching of ret-deficient kidneys. (A–D) Urogenital block explants including the Wolffian duct (wd), mesonephros (meso), and metanephros (meta) from E11 ret−/− (A and B), ret+/− (C), and ret+/+ (D) mouse embryos. The urogenital blocks from each embryo were separately cultured for 4 d, one side without GDNF (A, C and D) and the other one with 50 ng/ml of GDNF (B). The explants were fixed and immunolabeled as whole mounts with pan-cytokeratin antibodies. Bar, 200 μm. (E) The number of ureteric branches of ret−/−, ret+/−, and ret+/+ kidneys with or without GDNF supplementation. The results represent the means ± SEM. GDNF significantly increases ureteric branch number in ret−/− explants compared with the control media (P < 0.01).
Mentions: To analyze the possible role of Ret-independent, GFRα1-mediated signaling in ureteric budding and branching during nephrogenesis, we tested the ability of exogenous GDNF to induce ureteric budding or sustain its branching in ret-deficient mice. Embryonic day (E)11 ret−/− urogenital blocks including kidney rudiments were cultured for 4 d without or with 50 ng/ml of GDNF (Fig. 1) . As expected, the ureteric buds of ret−/− mice did not branch or branched rudimentarily in the control media (Schuchardt et al., 1996). When the culture medium was supplemented with GDNF, the number of ureteric bud tips in the hypodysplastic kidneys of ret-deficient mice was increased but not to the level seen in wild-type kidneys (Fig. 1, B and D). Exogenous GDNF increased the number of ureteric bud tips in ret−/−, ret+/−, and wild-type kidney explants (Fig. 1 E). However, with or without exogenous GDNF the number of ret−/− urogenital explants completely lacking a ureteric bud remained the same (Table I). Thus, Ret-independent signaling by GDNF has an apparent role in the ureteric branching but may be less significant in the primary bud formation.

Bottom Line: However, GDNF does not immunoprecipite Met, making a direct interaction between GDNF and Met highly improbable.The GDNF-induced branching of MDCK cells requires Src activation, whereas the HGF-induced branching does not.Our data show a mechanism for the GDNF-induced branching morphogenesis in non-Ret signaling.

View Article: PubMed Central - PubMed

Affiliation: Developmental Biology, Institute of Biomedicine, University of Helsinki, FIN-00014 Helsinki, Finland.

ABSTRACT
Glial cell line-derived neurotrophic factor (GDNF) and hepatocyte growth factor (HGF) are multifunctional signaling molecules in embryogenesis. HGF binds to and activates Met receptor tyrosine kinase. The signaling receptor complex for GDNF typically includes both GDNF family receptor alpha1 (GFRalpha1) and Ret receptor tyrosine kinase. GDNF can also signal independently of Ret via GFRalpha1, although the mechanism has remained unclear. We now show that GDNF partially restores ureteric branching morphogenesis in ret-deficient mice with severe renal hypodysplasia. The mechanism of Ret-independent effect of GDNF was therefore studied by the MDCK cell model. In MDCK cells expressing GFRalpha1 but no Ret, GDNF stimulates branching but not chemotactic migration, whereas both branching and chemotaxis are promoted by GDNF in the cells coexpressing Ret and GFRalpha1, mimicking HGF/Met responses in wild-type MDCK cells. Indeed, GDNF induces Met phosphorylation in several ret-deficient/GFRalpha1-positive and GFRalpha1/Ret-coexpressing cell lines. However, GDNF does not immunoprecipite Met, making a direct interaction between GDNF and Met highly improbable. Met activation is mediated by Src family kinases. The GDNF-induced branching of MDCK cells requires Src activation, whereas the HGF-induced branching does not. Our data show a mechanism for the GDNF-induced branching morphogenesis in non-Ret signaling.

Show MeSH
Related in: MedlinePlus