Radial Glial Cell-Derived VCAM1 Regulates Cortical Angiogenesis Through Distinct Enrichments in the Proximal and Distal Radial Processes

Endothelial-derived angiocrine factors as instructors of embryonic development

Blood vessels are well-known to play roles in organ development and repair, primarily owing to their fundamental function in delivering oxygen and nutrients to tissues to promote their growth and homeostasis. Endothelial cells however are not merely passive conduits for carrying blood. There is now evidence that endothelial cells of the vasculature actively regulate tissue-specific development, morphogenesis and organ function, as well as playing roles in disease and cancer. Angiocrine factors are growth factors, cytokines, signaling molecules or other regulators produced directly from endothelial cells to instruct a diverse range of signaling outcomes in the cellular microenvironment, and are critical mediators of the vascular control of organ function. The roles of angiocrine signaling are only beginning to be uncovered in diverse fields such as homeostasis, regeneration, organogenesis, stem-cell maintenance, cell differentiation and tumour growth. While in some cases the specific angiocrine factor involved in these processes has been identified, in many cases the molecular identity of the angiocrine factor(s) remain to be discovered, even though the importance of angiocrine signaling has been implicated. In this review, we will specifically focus on roles for endothelial-derived angiocrine signaling in instructing tissue morphogenesis and organogenesis during embryonic and perinatal development.

Preclinical neurorehabilitation with environmental enrichment confers cognitive and histological benefits in a model of pediatric asphyxial cardiac arrest

Pediatric asphyxial cardiac arrest (ACA) often leaves children with physical, cognitive, and emotional disabilities that affect overall quality of life, yet rehabilitation is neither routinely nor systematically provided. Environmental enrichment (EE) is considered a preclinical model of neurorehabilitation and thus we sought to investigate its efficacy in our established model of pediatric ACA. Male Sprague-Dawley rat pups (post-natal day 16-18) were randomly assigned to ACA (9.5 min) or Sham injury. After resuscitation, the rats were assigned to 21 days of EE or standard (STD) housing during which time motor, cognitive, and anxiety-like (i.e., affective) outcomes were assessed. Hippocampal CA1 cells were quantified on post-operative day-22. Both ACA + STD and ACA + EE performed worse on beam-balance vs. Sham controls (p < 0.05) and did not differ from one another overall (p > 0.05); however, a single day analysis on the last day of testing revealed that the ACA + EE group performed better than the ACA + STD group (p < 0.05) and did not differ from the Sham controls (p > 0.05). Both Sham groups performed better than ACA + STD (p < 0.05) but did not differ from ACA + EE (p > 0.05) in the open field test. Spatial learning and declarative memory were improved and CA1 neuronal loss was attenuated in the ACA + EE vs. ACA + STD group (p < 0.05). Collectively, the data suggest that providing rehabilitation after pediatric ACA can reduce histopathology and improve motor and cognitive ability.

Reciprocal Interaction between Vascular Filopodia and Neural Stem Cells Shapes Neurogenesis in the Ventral Telencephalon

Angiogenesis and neurogenesis are tightly coupled during embryonic brain development. However, little is known about how these two processes interact. We show that nascent blood vessels actively contact dividing neural stem cells by endothelial filopodia in the ventricular zone (VZ) of the murine ventral telencephalon; this association is conserved in the human ventral VZ. Using mouse mutants with altered vascular filopodia density, we show that this interaction leads to prolonged cell cycle of apical neural progenitors (ANPs) and favors early neuronal differentiation. Interestingly, pharmacological experiments reveal that ANPs induce vascular filopodia formation by upregulating vascular endothelial growth factor (VEGF)-A in a cell-cycle-dependent manner. This mutual relationship between vascular filopodia and ANPs works as a self-regulatory system that senses ANP proliferation rates and rapidly adjusts neuronal production levels. Our findings indicate a function of vascular filopodia in fine-tuning neural stem cell behavior, which is the basis for proper brain development.