WNT Mimetic-Induced Lacrimal Gland Regeneration Reverses Aqueous Tear Deficiency.

PURPOSE: Dry eye disease is characterized by abnormal tear film composition and inflammation. Disruptions in the presence or secretory function of acinar cells can result in dry eye, leading to discomfort, damage, and vision loss. Although tear replacement and anti-inflammatory treatments have been investigated thoroughly, a method to induce epithelial restoration is lacking. Here, we asked whether WNT signaling activation via an antibody-based WNT mimetic platform might activate lacrimal gland acinar cells and restore tear secretion. METHODS: Primary murine lacrimal gland cells were used to establish three-dimensional acinar cell organoids. Dry eye disease was modeled in mice using a lacrimal gland excretory duct ligation. Transcriptional and cellular changes were investigated using single-cell sequencing. RESULTS: Frizzled and LRP5/6 receptors, which are essential for WNT signal transduction, are expressed in glandular acinar cells in vivo. We showed that murine acinar cells can be expanded as organoids by using WNT signaling activation. Here, we demonstrate that WNT signaling is an essential factor for acinar cell proliferation ex vivo. In a mouse model of dry eye disease, and intra-lacrimal gland treatment with a WNT mimetic targeting FZD1, 2, and 7 reversed aqueous tear deficiency. After excretory duct ligation damage, WNT mimetic treatment promoted acinar cell restoration and increased detectable tear volume production. CONCLUSIONS: We demonstrate a role for WNT signaling in acinar cell proliferation. Our findings extend the potential for WNT pathway activation via a ligand mimetic platform to lacrimal gland regeneration. Pathway activation results in adult acinar cell proliferation in vitro and in vivo and tissue recovery. TRANSLATIONAL RELEVANCE: Our novel WNT mimetic platform offers a promising alternative to symptom-focused treatments by actively stimulating acinar cell proliferation and restoration.