Neuropeptide Y functions as a facilitator of GDNF-induced budding of the Wolffian duct

Abstract

Ureteric bud (UB) emergence from the Wolffian duct (WD), the initiating step in metanephric kidney morphogenesis, is dependent on GDNF; however, GDNF by itself is generally insufficient to induce robust budding of the isolated WD in culture. Thus, additional factors, presumably peptides or polypeptide growth factors, might be involved. Microarray data from in vivo budding and nonbudding conditions were analyzed using non-negative matrix factorization followed by gene ontology filtering and network analysis to identify sets of genes that are highly regulated during budding. These included the GDNF co-receptors GFR1 and RET, as well as neuropeptide Y (NPY). By using ANOVA with pattern matching, NPY was also found to correlate most significantly to the budded condition with a high degree of connectedness to genes with developmental roles. Exogenous NPY [as well as its homolog, peptide YY (PYY)] augmented GDNF-dependent budding in the isolated WD culture; conversely, inhibition of NPY signaling or perturbation of NPY expression inhibited budding, confirming that NPY facilitates this process. NPY was also found to reverse the decreased budding, the downregulation of RET expression, the mislocalization of GFR1, and the inhibition of AKT phosphorylation that resulted from the addition of BMP4 to the isolated WD cultures, suggesting that NPY acts through the budding pathway and is reciprocally regulated by GDNF and BMP4. Thus, the outgrowth of the UB from the WD might result from a combination of the upregulation of the GDNF receptors together with genes that support GDNF signaling in a feed-forward loop and/or counteraction of the inhibitory pathway regulated by BMP4.

Characterization of neuropeptide Y in snakeskin gourami and the change in its expression due to feeding status and melanocortin 4 receptor expression

“…NPY has been reported to be involved in multiple physiological processes [10,49], and its expression was observed in the peripheral tissues of mammals [13]. In contrast, the expression of NPY was confined to the brain in chicken, sea bass, Japanese flounder, and channel catfish [2,4,23,26].…”

“…Its mature peptide form consists of 36 amino acids, and it was first discovered in the pig brain [48]. It has been reported to be a key neuropeptide in the control of food intake and energy homeostasis, as well as in a variety of other physiological processes [10,49]. A daily rhythm and prandial variation in NPY expression were demonstrated in the rat, goldfish and tiger puffer [18,36,55].…”

GDNF-independent ureteric budding: role of PI3K-independent activation of AKT and FOSB/JUN/AP-1 signaling

“…These so called “semi-clean” WDs were cultured on top of Transwell filters (0.4 µm pore size; Costar, Cambridge, MA) for up to 7 days in DMEM/F12 supplemented with 10% FBS in the absence or presence of various growth factors and/or inhibitors as indicated (Maeshima et al, 2007; Rosines et al, 2007; Choi et al, 2009; Tee et al, 2010). …”

“…Embryos were genotyped (Schuchardt et al, 1994) and kidneys were visually inspected for the presence of a ureteric bud before processing for microarray analysis. Wild-type and mutant kidneys were lysed, total RNA was extracted (RNEasy Micro kit; Qiagen, Germantown, MD), processed and hybridized to the GeneChip Mouse Genome 430 2.0 microarray (Affymetrix) by the UCSD genechip core by as previously described (Choi et al, 2009; Tee et al, 2010). GeneSpring GX 11.5 (Agilent, Santa Clara, CA) was used to analyze fold-change data.…”

Cell Biology of Ureter Development

“…An autocrine loop involving neuropeptide Y may enhance the commitment of these ND cells to budding. 21 ND budding is preceded by increased epithelial proliferation 22 and thickening to a pseudostratified epithelium. 23 RET signaling leads to rearrangement of ND cells such that those with the greatest ERK/PI3K/PLC activation move together and produce the bud.…”