Abstract
Purpose :
Dry eye is a multifactorial disease impacting the ocular surface and tear film, with over 344 million people worldwide affected. Patients experience itching, recurrent conjunctivitis, and visual impairments, leading to blindness in severe cases. Hypovolemic dry eye, resulting from lacrimal gland insufficiency, is associated with the most severe disease progression. Various animal models have demonstrated that the lacrimal gland possesses a lifelong regenerative capacity and can fully recover after acute damage. However, the underlying mechanisms remain unclear. Therefore, we aim to uncover the intrinsic regeneration mechanisms of the lacrimal gland to derive therapeutic options for patients with aqueous-deficient dry eye (ADDE).
Methods :
Primary lacrimal gland acinar epithelial cells (LGEC) were obtained as explants of neonatal mice. Characterization involved the confirmation of lacrimal gland-specific markers while excluding fibroblastic and myoepithelial markers by PCR and immunocytochemistry. Additionally, the secretory capacity of the murine LGEC (mLGEC) was assessed using a hexosaminidase assay, measuring the enzymatic activity indicative of lysosomal exocytosis. Subsequently, the intrinsic regeneration mechanisms of mLGEC were determined through transcriptome analysis. The signal pathways involved in regeneration according to KEGG were analysed, and promising proteins were further investigated.
Results :
LGEC marker such as FOXC1, PAX6, and LTF, as well as acinar cell markers like AQP5 and SOX10 were maintained in mLGECs. The concentrations of fibroblast and myoepithelial cell markers correspond to native tissue. Stimulation with carbachol and dbcamp, both of which induce secretion in mLGECs, revealed the secretory potential of the cells. After injury, initial signs of regeneration were observed within one hour. Transcriptome analysis showed that the TNF-, the IL-17-, and the MAPK signaling pathway are responsive and various growth factors were upregulated.
Conclusions :
We successfully have established an in vitro model for lacrimal gland injury and demonstrated spontaneous regeneration. Furthermore, our project revealed key pathways involved in the intrinsic regenerative mechanisms of LGECs. Subsequent experiments with the identified growth factors will show how they affect the regenerative potential of the lacrimal gland. This knowledge may help to derive therapeutic options for patients with ADDE.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.