Kidney structural abnormalities are amongst the leading causes of pediatric chronic kidney disease, producing significant morbidity and mortality. Understanding how different kidney lineages develop and interact is critical for making an impact on structural kidney disease. While most of the field has focused on ureteric, nephrogenic and stromal lineages, few have interrogated the role of the vasculature in the process of kidney development, except as it relates to the glomerulus. Moreover, the origin of the kidney vasculature has been debated to come from either the nephrogenic mesenchyme (within the kidney) or invading vessels. Our preliminary data strongly suggests that the renal cortical stroma gives rise to a significant percentage of the endothelium in the kidney that is critical for kidney development. In transgenic mice, co-expression of stromal and endothelial markers was detected in subsets of kidney cells at different embryonic stages by fluorescent activated cell sorting (FACS) and immunofluorescence. FACS analysis of permanently tagged renal cortical stromal cells showed a significant proportion of the surviving cells were now endothelial cells in post-natal kidneys. Immunofluorescence revealed lineage tagged renal stromal-derived endothelial cells gave rise to a significant portion of the peritubular capillary network, but not glomerular capillaries. Functionally, embryonic stroma-positive cells differentiated into tubular networks that expressed endothelial markers in an in vitro endothelial tubulogenesis assay and endocytosed Acetylated Low density lipoprotein (a functional endothelial cell assay). To test whether renal stroma gives rise to renal endothelium in vivo, Flk1 (critical for endothelial development) was conditionally deleted in the renal stroma (Flk1ST-/- mice). Flk1ST-/- mice had a dramatic congenital kidney defect and dilated peritubular capillaries while containing normal-appearing glomerular capillaries. An apparent reduction in ureteric branching and nephron formation was also observed. Thus, the hypothesis is that a subset of renal cortical stromal cells are precursors to many of the renal peritubular endothelial cells and that this endothelial cell population is necessary for normal patterning of other lineages in the kidney. To test this hypothesis, the following aims are proposed:
Aim 1 : To determine the functional potential of the renal cortical stroma to develop into endothelium. Foxd1 stroma will be isolated by FACS and subjected to in vitro conditions to drive endothelial cell differentiation.
Aim 2 : Determine the fate of Foxd1/Flk1 cells and how deletion of these cells affects vascular development. A comprehensive histological, structural, and functional analysis of the endothelium and vasculature will be performed.
Aim 3 : To investigate the role of the FoxD1- derived endothelium in formation of the kidney. A thorough histological, structural and physiological assessment of the renal lineages of the Flk1ST-/- mice will be performed. These studies will provide new insights into the origins of renal endothelium and their contribution to renal development. Manipulation of this novel progenitor pool may therapeutically impact vascular related congenital kidney abnormalities and diseases.

Public Health Relevance

Kidney birth defects are the most common cause of kidney disease in children often leading to early death. We have mouse mutants that show how blood vessel cells are important in how the fetal kidney forms. A greater understanding of how blood vessel cells contribute to kidney birth defects will lead to new therapies for children with these diseases.

National Institute of Health (NIH)
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Research Scientist Development Award - Research & Training (K01)
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Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
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Rankin, Tracy L
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University of Pittsburgh
Schools of Medicine
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Galambos, Csaba; Sims-Lucas, Sunder; Ali, Noorjahan et al. (2015) Intrapulmonary vascular shunt pathways in alveolar capillary dysplasia with misalignment of pulmonary veins. Thorax 70:84-5
Stolz, Donna Beer; Sims-Lucas, Sunder (2015) Unwrapping the origins and roles of the renal endothelium. Pediatr Nephrol 30:865-72
Junttila, Sanna; Saarela, Ulla; Halt, Kimmo et al. (2015) Functional genetic targeting of embryonic kidney progenitor cells ex vivo. J Am Soc Nephrol 26:1126-37
Chu, Jessica Y S; Sims-Lucas, Sunder; Bushnell, Daniel S et al. (2014) Dicer function is required in the metanephric mesenchyme for early kidney development. Am J Physiol Renal Physiol 306:F764-72
Rymer, Christopher; Paredes, Jose; Halt, Kimmo et al. (2014) Renal blood flow and oxygenation drive nephron progenitor differentiation. Am J Physiol Renal Physiol 307:F337-45
Galambos, Csaba; Sims-Lucas, Sunder; Abman, Steven H (2014) Three-dimensional reconstruction identifies misaligned pulmonary veins as intrapulmonary shunt vessels in alveolar capillary dysplasia. J Pediatr 164:192-5
Hum, Stephanie; Rymer, Christopher; Schaefer, Caitlin et al. (2014) Ablation of the renal stroma defines its critical role in nephron progenitor and vasculature patterning. PLoS One 9:e88400
Galambos, Csaba; Sims-Lucas, Sunder; Abman, Steven H (2013) Histologic evidence of intrapulmonary anastomoses by three-dimensional reconstruction in severe bronchopulmonary dysplasia. Ann Am Thorac Soc 10:474-81
Sims-Lucas, Sunder; Schaefer, Caitlin; Bushnell, Daniel et al. (2013) Endothelial Progenitors Exist within the Kidney and Lung Mesenchyme. PLoS One 8:e65993