Biophysics in oviduct: Planar cell polarity, cilia, epithelial fold and tube morphogenesis, egg dynamics

Abstract

Organs and tissues in multi-cellular organisms exhibit various morphologies. Tubular organs have multi-scale morphological features which are closely related to their functions. Here we discuss morphogenesis and the mechanical functions of the vertebrate oviduct in the female reproductive tract, also known as the fallopian tube. The oviduct functions to convey eggs from the ovary to the uterus. In the luminal side of the oviduct, the epithelium forms multiple folds (or ridges) well-aligned along the longitudinal direction of the tube. In the epithelial cells, cilia are formed orienting toward the downstream of the oviduct. The cilia and the folds are supposed to be involved in egg transportation. Planar cell polarity (PCP) is developed in the epithelium, and the disruption of the Celsr1 gene, a PCP related-gene, causes randomization of both cilia and fold orientations, discontinuity of the tube, inefficient egg transportation, and infertility. In this review article, we briefly introduce various biophysical and biomechanical issues in the oviduct, including physical mechanisms of formation of PCP and organized cilia orientation, epithelial cell shape regulation, fold pattern formation generated by mechanical buckling, tubulogenesis, and egg transportation regulated by fluid flow. We also mention about possible roles of the oviducts in egg shape formation and embryogenesis, sinuous patterns of tubes, and fold and tube patterns observed in other tubular organs such as the gut, airways, etc.

Spatiotemporal transcriptional dynamics of the cycling mouse oviduct

“…4E). The PCP system is essential for normal polarized ciliary beating in the oviduct, so most PCP genes are expressed in the oviduct (Koyama et al, 2019; Shi et al, 2014). Strikingly however, none displayed enrichment along the AP axis (Fig.…”

Planar cell polarity governs the alignment of the nasopharyngeal epithelium in mammals

“…Coordinated cilia orientation was another manifestation of PCP [4,16,18,19]. For concerted, directional movement, the basal feet of cilia were uniformly aligned within individual cells and among neighbouring cells along the long axis of tissue [5,7]. This type of ciliary alignment along the plane of the epithelium is termed PCP.…”

“…Multiciliated epithelial cells in brain ventricles also have marked planar polarisation, which determines the orientation of ciliary beating and the propulsion of the cerebrospinal fluid [6]. Disruption of the PCP pathway leads to randomisation of cilia, discontinuity of oviduct tubes, inefficient egg transportation and infertility [7].…”

Celsr1 and CAMSAP3 differently regulate intercellular and intracellular cilia orientation in oviduct multiciliated cells

“…In epithelial cells, in addition to apicobasal polarity, planar cell polarity (PCP) runs perpendicular to the apicobasal plane within the plane of the epithelium (Butler and Wallingford, 2017;Henderson et al, 2018;Aw and Devenport, 2017). For example, in the oviduct, the axis of the epithelial PCP lies along the longitudinal axis of the oviduct, and the morphological polarities extend over multiple cells, such as the folded structure formed by the epithelial sheet, the elongation of the apical surface of MCCs, and the orientation of multicilia (Shi et al, 2014;Koyama et al, 2016;Koyama et al, 2019). PCP factors are proteins involved in regulating PCP that were initially identified by genetic screens performed in Drosophila melanogaster; many are conserved in vertebrates (Butler and Wallingford, 2017;Devenport 2014;Yang and Mlodzik, 2015;Hale and Strutt, 2015;Boutin et al, 2012;Shi et al, 2013;Shi et al, 2016a).…”