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. Author manuscript; available in PMC: 2022 Jan 1.
Published in final edited form as: Ocul Surf. 2020 Apr 29;19:104–114. doi: 10.1016/j.jtos.2020.04.008

Figure 1: SPMs maintain ocular surface health and restore tissue homeostasis.

Figure 1:

During ocular homeostasis tears, cornea, conjunctiva and lymph nodes contain a basal tone of SPMs. SPMs can be produced by corneal epithelial cells and potentially tear neutrophils, which express required biosynthetic enzymes 5-LOX and 15-LOX. Cognate SPM receptors (not shown) are expressed on corneal and conjunctival epithelium, DC, fibroblasts, neutrophil, APC and lymphocytes. Following corneal injury or infection, activated neutrophil are rapidly recruited to the ocular surface and amplify formation of SPMs, which can inhibit DC maturation, myofibroblast proliferation and IL-1β and TGFβ production. SPMs also promote corneal wound healing by enhancing re-epithelialization, heme-oxygenase expression and corneal nerve regeneration. Mesenchymal stem cells (MSC), which have immune-regulatory and wound healing properties can produce SPMs. In the healthy conjunctiva, SPMs promote normal mucin secretion by goblet cells, however, during allergic responses exogenous SPM treatment reduces histamine mediated production of mucins. In draining lymph nodes SPM control APC interaction with lymphocytes and directly act on effector T cells to inhibit Th1 and Th17 and enhance Treg responses.