When and where do epithelia form in the embryonic kidney? There is an event called """"""""induction"""""""", the result of signaling from the ureteric bud that stimulates the mesenchyme to convert into epithelia. But is this one event or do multiple signals, working in series or in parallel drive cell conversion? We began looking for inductive factors by making a cell line from the ureteric bud. We grew 35,000 flasks and tested its fractions on mesenchyme taken from the rat when the UB hadjust invaded. We discovered 1. mesenchyme dies without the UB but 2.can be rescued by UB factors and 3. can be converted when two groups offactors are combined. We purified the following survival factors-FGF-2, TlMP-2, SHH and endostatin. The inductive factors included LIF, lipocalin-2 (Ngal, the most highly expressed factor in acute renal failure), a fragment of urokinase (unpublished) and a partially purified, powerful inducer we call ANX. The inducers act like switches?ifpresent for only 24 hrs, they drive a single mesenchyme to produce 100 tubules and recognizable nephrons. LIF was the first known purified nephron inducer. To further our search for molecules that control conversion, we isolated 1000 tips from stalks of the in vivo ureteric bud and we identified its secreted factors using two different species. Amazingly, one of the most expressed tip proteins was a chaperone for LIF-like molecules, known as CLF. In fact, the embryonic kidney likely expresses not only LIF but 2 novel cytokines, and there is good evidence for yet a third. Evaluation of the common receptor KO shows a hypoplastic phenotype that must now be further evaluated. This was an unexpected confirmation of our original work. We need now to define the response of the mesenchymeto the many inducers. We show by comparison, that a common pathway of conversion exists. We find unexpected Wnt regulators, transcription and growth factors downstream of the inducers, which we will analyze by applying newtechniques of gene expression and inhibition. Finally as we define the inductive pattern,we ask where do these processes really occur? Is polarity induced uniformly as designed by our bioassays,or have we only assayed one stage in a long pathway. We apply the basic ideas and tools of cell biologyto define the course of polarization and establish a fluorescent polarity mouse to evaluate the entire transition form mesenchyme to epithelia.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK058872-08
Application #
7393669
Study Section
Urologic and Kidney Development and Genitourinary Diseases Study Section (UKGD)
Program Officer
Hoshizaki, Deborah K
Project Start
2001-03-01
Project End
2011-03-31
Budget Start
2008-04-01
Budget End
2009-03-31
Support Year
8
Fiscal Year
2008
Total Cost
$317,509
Indirect Cost
Name
Columbia University (N.Y.)
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
621889815
City
New York
State
NY
Country
United States
Zip Code
10032
Correnti, Colin; Richardson, Vera; Sia, Allyson K et al. (2012) Siderocalin/Lcn2/NGAL/24p3 does not drive apoptosis through gentisic acid mediated iron withdrawal in hematopoietic cell lines. PLoS One 7:e43696
Paragas, Neal; Qiu, Andong; Zhang, Qingyin et al. (2011) The Ngal reporter mouse detects the response of the kidney to injury in real time. Nat Med 17:216-22
Sola-Del Valle, David A; Mohan, Sumit; Cheng, Jen-Tse et al. (2011) Urinary NGAL is a useful clinical biomarker of HIV-associated nephropathy. Nephrol Dial Transplant 26:2387-90
Bao, Guanhu; Clifton, Matthew; Hoette, Trisha M et al. (2010) Iron traffics in circulation bound to a siderocalin (Ngal)-catechol complex. Nat Chem Biol 6:602-9
Parravicini, Elvira; Nemerofsky, Sheri L; Michelson, Kenneth A et al. (2010) Urinary neutrophil gelatinase-associated lipocalin is a promising biomarker for late onset culture-positive sepsis in very low birth weight infants. Pediatr Res 67:636-40
Li, Jau Yi; Paragas, Neal; Ned, Renee M et al. (2009) Scara5 is a ferritin receptor mediating non-transferrin iron delivery. Dev Cell 16:35-46
Paragas, Neal; Nickolas, Thomas L; Wyatt, Christina et al. (2009) Urinary NGAL marks cystic disease in HIV-associated nephropathy. J Am Soc Nephrol 20:1687-92
Huynh, Trang K; Bateman, David A; Parravicini, Elvira et al. (2009) Reference values of urinary neutrophil gelatinase-associated lipocalin in very low birth weight infants. Pediatr Res 66:528-32
Schmidt-Ott, Kai M; Barasch, Jonathan (2008) WNT/beta-catenin signaling in nephron progenitors and their epithelial progeny. Kidney Int 74:1004-8
Nickolas, Thomas L; Barasch, Jonathan; Devarajan, Prasad (2008) Biomarkers in acute and chronic kidney disease. Curr Opin Nephrol Hypertens 17:127-32

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