Overexpression of vascular endothelial growth factor in the germinal matrix induces neurovascular proteases and intraventricular hemorrhage.

Intracranial hemorrhage in preterm neonates may result in neonatal mortality and functional disabilities, but its pathogenic mechanisms are poorly defined and better therapies are needed. We used a tetracycline-regulated transgenic system to test whether the induction of vascular endothelial growth factor (VEGF) in the germinal matrix leads to intracranial hemorrhage. This genetic strategy initially induced a dense network of loosely adjoined endothelial cells and pericytes near lateral ventricles, similar to the immature vascular rete in human fetal brains.

Lymphatic ontogeny and effect of hypoplasia in developing lung.

The pulmonary lymphatic vasculature plays a vital role in maintaining fluid homeostasis required for efficient gas exchange at capillary alveolar barriers and contributes to lung fluid clearance at birth. To further understanding of pulmonary lymphatic function at birth, lineage-tracing analysis of mouse lung was used. Lineage analysis confirmed that lymphatic endothelial cells (LEC) bud from extrapulmonary lymphatics and demonstrated that LEC migrate into developing lung along precise pathways.

Effects of increased renal tubular vascular endothelial growth factor (VEGF) on fibrosis, cyst formation, and glomerular disease.

The role of vascular endothelial growth factor (VEGF) in renal fibrosis, tubular cyst formation, and glomerular diseases is incompletely understood. We studied a new conditional transgenic mouse system [Pax8-rtTA/(tetO)(7)VEGF], which allows increased tubular VEGF production in adult mice. The following pathology was observed.

NFATc1 regulates lymphatic endothelial development.

NFATc1 transcription factor is critical for lineage selection in T-cell differentiation, cardiac valve morphogenesis and osteoclastogenesis. We identified a role for calcineurin-NFAT signaling in lymphatic development and patterning. NFATc1 was colocalized with lymphatic markers Prox-1, VEGFR-3 and podoplanin on cardinal vein as lymphatic endothelial cells (LEC) are specified and as they segregate into lymph sacs and mature lymphatics.

Lymphangiogenesis in the developing lung promoted by VEGF-A.

Understanding the basic processes of late-stage pulmonary vascular development is essential as this period corresponds to the stage when preterm infants have increased chance of survival. During this period, refinement of the gas exchange unit leads to close apposition of the capillary vasculature and airway epithelium through thinning of the mesenchyme, formation of alveolar septae and functional adaptation of endothelial cells into vessels including pulmonary lymphatics. The pulmonary lymphatic network promotes efficient gas exchange through maintaining interstitial fluid balance.

Vascular endothelial growth factor-A induces prenatal neovascularization and alters bronchial development in mice.

Pulmonary vascular development requires precise temporal and spatial expression of vascular endothelial growth factor-A (VEGF-A). Diminished expression of VEGF-A in preterm infants may contribute to the pathophysiology of respiratory distress syndrome. Because exogenous replacement of VEGF-A has been proposed as a therapeutic for respiratory distress syndrome, we used conditional activation of VEGF-A in bronchial epithelial cells to assess the effects of increase of VEGF-A on lung morphogenesis and survival in the developing mouse.

Slit and robo expression in the developing mouse lung.

Mammalian lung development is mediated through complex interactions between foregut endoderm and surrounding mesenchyme. As airway branching progresses, the mesenchyme undergoes dramatic remodeling and differentiation. Little is understood about the mechanisms that direct mesenchymal organization during lung development.

Temporal and spatial regulation of VEGF-A controls vascular patterning in the embryonic lung.

Vascular endothelial growth factor-A (VEGF-A) is required for vascular development throughout the embryo and has been proposed to play an important role in pulmonary vascular patterning. Expressed by the embryonic respiratory epithelium, VEGF-A signals endothelial cells within the splanchnic mesenchyme. To refine understanding of the spatial and temporal role of VEGF-A in lung morphogenesis, isoform VEGF164 was expressed under conditional control in distal and proximal airway epithelial cells.

Mesenchymal expression of vascular endothelial growth factors D and A defines vascular patterning in developing lung.

The lung has specific vascular patterning requirements for effective gas exchange at birth, including alignment of airways and blood vessels and lymphatic vessels. Vascular endothelial growth factors (VEGF) are potent effectors of vascular development. We examined the temporal and spatial expression of VEGF-D and specific VEGF-A isoforms at each stage of lung development.