Assessing the distribution of tanycyte processes and their vascular contacts within the basal hypothalamus of mice

URIARTE M; REGGIANI PC; DE FRANCESCO PN; REYNALDO M; PERELLÓ M; CRESPO T; GOYA RG

Congreso; XXXV Congreso Anual de la Sociedad Argentina de Investigación en Neurociencia; 2020

Sociedad Argentina de Investigación en Neurociencia (SAN)

Hypothalamic tanycytes are specialized ependymal cells that line thefloor of the third ventricle and emit processes into the surroundinghypothalamic parenchyma. Given their strategic location, these cells arebelieved to play several key functions, including energy homeostasis, nutrientsensing, and hormonal transport and regulation. Here, we used an adenoviralvector expressing GFP (Rad-GFP) to label the ependymal walls, includingtanycytes and their processes, providing fine structural detail throughoutthese structures. By imaging a series of consecutive brain slices we obtained acollection of fluorescence z-stacks which we later re-combined into acontinuous volume spanning the basal hypothalamus. This was accomplished byapplying a global elastic registration procedure guided by local inter-stacklandmark pairs, using an image analysis pipeline we developed for the softwarepackage Fiji and its plugin TrakEM2. Following this procedure, we were able tomap the three-dimensional distribution of tanycyte processes throughout thesampled volume, as well as to describe and quantify several parameters,including the type and percentage of processes that extend to the differenthypothalamic nuclei, their overall morphology and orientation, and thedistribution of contact classes based on morphological criteria. Altogether,our results provide valuable insights for the further understanding of theseintriguing cells and their putative roles in the hypothalamic physiology.