Cell-lineage specificity of primary cilia during epididymis post-natal development

Abstract

30Primary cilia are sensory organelles that orchestrate major signaling pathways during organ 31 development and homeostasis. By using a double Arl13b/mCherry-Cetn2/GFP transgenic mouse 32 model, we characterized the spatio-temporal localization of primary cilia in the epididymis, from 33 birth to adulthood. We report here a constitutive localisation of primary cilia in peritubular 34 myoid cells and a dynamic profiling in differentiated epithelial cells throughout post-natal 35 development. While primary cilia are present at the apical pole of the undifferentiated epithelial 36 cells from birth to puberty, they are absent from the apical pole of the epithelium in adults, 37where they appear exclusively associated with cytokeratin 5-positive basal cells. Exogenous 38 labeling of primary cilia marker Arl13b and IFT88 confirmed the cell lineage specific localization 39 of primary cilia in basal cells and myoid cells in human epididymides. From whole epididymis 40 tissues and serum-free cultures of DC2 murine epididymal principal cell lines we determined 41 that primary cilia from the epididymis are associated with the polycystic kidney disease-related 42 proteins polycystin 1 (PC1) and polycystin 2 (PC2), and Gli3 Hedgehog signaling transcription 43 factor. Thus, our findings unveil the existence of primary cilia sensory organelles, which have the 44 potential to mediate mechano/ chemo-signaling events in the epididymis. 45