Development
Abstract
Congenital obstructive nephropathy is the principal cause of renal failure in infants and children. The underlying molecular and cellular mechanisms of this disease, however, remain largely undetermined. We generated a mouse model of congenital obstructive nephropathy that resembles ureteropelvic junction obstruction in humans. In these mice, calcineurin function is removed by the selective deletion of Cnb1 in the mesenchyme of the developing urinary tract using the Cre/lox system. This deletion results in reduced proliferation in the smooth muscle cells and other mesenchymal cells in the developing urinary tract. Compromised cell proliferation causes abnormal development of the renal pelvis and ureter, leading to defective pyeloureteral peristalsis, progressive renal obstruction, and, eventually, fatal renal failure. Our study demonstrates that calcineurin is an essential signaling molecule in urinary tract development and is required for normal proliferation of the urinary tract mesenchymal cells in a cell-autonomous manner. These studies also emphasize the importance of functional obstruction, resulting from developmental abnormality, in causing congenital obstructive nephropathy.
Authors
Ching-Pin Chang, Bradley W. McDill, Joel R. Neilson, Heidi E. Joist, Jonathan A. Epstein, Gerald R. Crabtree, Feng Chen
Abstract
Embryo liver morphogenesis takes place after gastrulation and starts with a ventral foregut evagination that reacts to factor signaling from both cardiac mesoderm and septum transversum mesenchyme. Current knowledge of the progenitor stem cell populations involved in this early embryo liver development is scarce. We describe here a population of 11-day postcoitus c-Kitlow(CD45/TER119)– liver progenitors that selectively expressed hepatospecific genes and proteins in vivo, was self-maintained in vitro by long-term proliferation, and simultaneously differentiated into functional hepatocytes and bile duct cells. Purified c-Kitlow(CD45/TER119)– liver cells cocultured with cell-depleted fetal liver fragments engrafted and repopulated the hepatic cell compartments of the latter organoids, suggesting that they may include the embryonic stem cells responsible for liver development.
Authors
Susana Minguet, Isabel Cortegano, Pilar Gonzalo, José-Alberto Martínez-Marin, Belén de Andrés, Clara Salas, David Melero, Maria-Luisa Gaspar, Miguel A.R. Marcos
Abstract
Kidney disease affects over 20 million people in the United States alone. Although the causes of renal failure are diverse, the glomerular filtration barrier is often the target of injury. Dysregulation of VEGF expression within the glomerulus has been demonstrated in a wide range of primary and acquired renal diseases, although the significance of these changes is unknown. In the glomerulus, VEGF-A is highly expressed in podocytes that make up a major portion of the barrier between the blood and urinary spaces. In this paper, we show that glomerular-selective deletion or overexpression of VEGF-A leads to glomerular disease in mice. Podocyte-specific heterozygosity for VEGF-A resulted in renal disease by 2.5 weeks of age, characterized by proteinuria and endotheliosis, the renal lesion seen in preeclampsia. Homozygous deletion of VEGF-A in glomeruli resulted in perinatal lethality. Mutant kidneys failed to develop a filtration barrier due to defects in endothelial cell migration, differentiation, and survival. In contrast, podocyte-specific overexpression of the VEGF-164 isoform led to a striking collapsing glomerulopathy, the lesion seen in HIV-associated nephropathy. Our data demonstrate that tight regulation of VEGF-A signaling is critical for establishment and maintenance of the glomerular filtration barrier and strongly supports a pivotal role for VEGF-A in renal disease.
Authors
Vera Eremina, Manish Sood, Jody Haigh, András Nagy, Ginette Lajoie, Napoleone Ferrara, Hans-Peter Gerber, Yamato Kikkawa, Jeffrey H. Miner, Susan E. Quaggin
Abstract
Preadipocyte factor-1 (Pref-1) is a transmembrane protein highly expressed in preadipocytes. Pref-1 expression is, however, completely abolished in adipocytes. The extracellular domain of Pref-1 undergoes two proteolytic cleavage events that generate 50 and 25 kDa soluble products. To understand the function of Pref-1, we generated transgenic mice that express the full ectodomain corresponding to the large cleavage product of Pref-1 fused to human immunoglobulin-γ constant region. Mice expressing the Pref-1/hFc transgene in adipose tissue, driven by the adipocyte fatty acid–binding protein (aP2, also known as aFABP) promoter, showed a substantial decrease in total fat pad weight. Moreover, adipose tissue from transgenic mice showed reduced expression of adipocyte markers and adipocyte-secreted factors, including leptin and adiponectin, whereas the preadipocyte marker Pref-1 was increased. Pref-1 transgenic mice with a substantial, but not complete, loss of adipose tissue exhibited hypertriglyceridemia, impaired glucose tolerance, and decreased insulin sensitivity. Mice expressing the Pref-1/hFc transgene exclusively in liver under the control of the albumin promoter also showed a decrease in adipose mass and adipocyte marker expression, suggesting an endocrine mode of action of Pref-1. These findings demonstrate the inhibition of adipogenesis by Pref-1 in vivo and the resulting impairment of adipocyte function that leads to the development of metabolic abnormalities.
Authors
Kichoon Lee, Josep A. Villena, Yang Soo Moon, Kee-Hong Kim, Sunjoo Lee, Chulho Kang, Hei Sook Sul
Abstract
Research Article
Authors
Akiyoshi Uemura, Minetaro Ogawa, Masanori Hirashima, Takashi Fujiwara, Shinji Koyama, Hitoshi Takagi, Yoshihito Honda, Stanley J. Wiegand, George D. Yancopoulos, Shin-Ichi Nishikawa
Abstract
Research Article
Authors
Christine Fritsch, Elzbieta A. Swietlicki, Olivier Lefebvre, Michele Kedinger, Hristo Iordanov, Marc S. Levin, Deborah C. Rubin
Abstract
Research Article
Authors
Lydie Cassard, Joël F.G. Cohen-Solal, Annie Galinha, Xavier Sastre-Garau, Claire Mathiot, Jérôme Galon, Thierry Dorval, Alain Bernheim, Wolf H. Fridman, Catherine Sautès-Fridman
Abstract
Research Article
Authors
Wolfgang E. Gallwitz, Theresa A. Guise, Gregory R. Mundy
Abstract
Research Article
Authors
Dipak Panigrahy, Samuel Singer, Lucy Q. Shen, Catherine E. Butterfield, Deborah A. Freedman, Emy J. Chen, Marsha A. Moses, Susan Kilroy, Stefan Duensing, Christopher Fletcher, Jonathan A. Fletcher, Lynn Hlatky, Philip Hahnfeldt, Judah Folkman, Arja Kaipainen
UV-induction of keratinocyte endothelin-1 downregulates E-cadherin in melanocytes and melanoma cells
Abstract
Research Article
Authors
Sumayah Jamal, Robert J. Schneider
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