Localization of phosphatidylinositol phosphate 5 kinase γ, phospholipase β3 and diacylglycerol kinase ζ in corneal epithelium in comparison with conjunctival epithelium of mice

• Published in: Experimental eye research Vol. 223; p. 109205
• Main Authors: Pakkarato, Sawetree, Sakagami, Hiroyuki, Goto, Kaoru, Watanabe, Masahiko, Kondo, Hisatake, Hipkaeo, Wiphawi, Chomphoo, Surang
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.10.2022
• Subjects: Conjunctiva; Cornea; DGKζ; Immunohistochemistry; Mice; PIP5Kγ; PLCβ3; Immunohistochemistry; Cornea; PLCβ3; Mice; PIP5Kγ; Conjunctiva; DGKζ
• ISSN: 0014-4835; 1096-0007
• DOI: 10.1016/j.exer.2022.109205

Based on the theory that the phosphoinositide (PI) signal is involved in the physiology of cornea and conjunctiva, we examined the localization in the mouse anterior ocular epithelia of immunoreactivities for phosphatidylinositol 4-phosphate 5-kinase (PIP5K), phospholipase C (PLC) and diacylglycerol kinase (DGK), enzymes that work sequentially in PI cycle. Immunoreactivity for PIP5Kγ in the corneal epithelium, including the limbus, was distinct in adults in contrast to faint or negligible immunoreactivity in the conjunctival epithelium in neonatal mice. This adult localization pattern was first recognized at the postnatal time of eyelid opening. Immunoreactivity for PLCβ3 was rather equally distinct throughout the entire corneal and conjunctival epithelia in adults. DGKζ-immunoreactive nuclei were mainly localized in the basal half domain of the corneal epithelium but in both basal and apical domains of the conjunctival epithelium in adults. This nuclear immunoreactivity was at weak or negligible levels in the peripheral and limbus cornea and in a considerable portion of the bulbar conjunctival epithelium continuous with the limbus. The adult patterns for PLCβ3 and DGKζ were already present at birth. The present findings suggest the following possibilities on the functional significance of the three enzyme molecules. PIP5Kγ is involved in cornea-specific functions such as bright-field vision, including corneal transparency, and in the stability of epithelial junctions, for which there seems to be a much higher requirement in the corneal epithelium than in the conjunctival epithelium. PLCβ3 is involved from birth in as-yet undefined functions exerted ubiquitously from birth in both corneal and conjunctival epithelia. DGKζ is involved in regulation from birth of the transcription in epithelial cells, including apoptosis as well as regulation of mitosis of epithelial cells in both cornea and conjunctiva, with the transcription involvement more apparent in the conjunctiva, although it does not work in stem cells of the corneal limbus. •PIP5Kγ localized in the corneal epithelium including the limbus at adult.•PLCβ3 localized throughout the corneal and conjunctival epithelia at adult.•DGKζ was in corneal basal epithelial cells and conjunctival basal and apical cells.•PIP5Kγ was first detected throughout the central cornea at P2W.•PLCβ3 and DGKζ were discerned in the corneal and conjunctival epithelia at P0W.