Abstract
Purpose :
We previously reported that neurotrophin (NT) production decreased in mouse corneas in dry eye disease (DED). Since corneal leukocytes are in close proximity with nerves and participate in neuronal maintenance, we aimed to determine NT production in corneal leukocyte populations, including plasmacytoid dendritic cells (pDC), conventional DCs (cDC), and macrophages (MØ) in naive and DED corneas.
Methods :
Mice were placed in a DED chamber with low humidity and high air flow and received injection of 0.5mg scopolamine for 14 days, monitored for signs of DED. Corneal single cell suspension was stained with antibodies for markers of pDC, cDC, MØ, and for nerve growth factor (NGF), brain-derived NF (BDNF), NT3, and NT4, analyzed with a flow cytometer.
Results :
DED mice developed clinical signs of DED. Higher percentages of pDCs produced NTs than the cDCs and MØs: NGF (average 76% vs 30% vs 34% for pDCs, cDCs, and MØs, respectively, naïve corneas; 62% vs 22% vs 20% DED corneas), BDNF (86% vs 31% vs 46% naïve corneas; 62% vs 22% vs 20%, DED corneas), NT3 (75% vs 10% vs 17% naïve corneas; 62% vs 15% vs 18% DED corneas), NT4 (84% vs 19% vs 28% naïve corneas, 78% vs 18% vs 16% DED corneas) (all p<0.001). Also, individual pDCs produced more NTs than the cDCs and MØs in naïve corneas: NGF (2.6 and 2.1 fold (F) to cDCs and MØ, respectively), BDNF (2.6 and 2.2 F), NT3 (2.1 and 1.6 F), NT4 (3.0 and 3.3 F) (all p<0.01), and in DED corneas, more NGF than cDCs (1.9 F), more BDNF than cDCs and MØs (2.0 and 1.6 F), more NT3 (2.1 and 2.1 F), and more NT4 (2.9 and 2.8 F) (all p<0.001). Interestingly, SiglecH+ pDCs produced less NGF (75% of the SiglecH- pDC NGF production), NT3 (54%), and NT4 (61%) (all p<0.05) than SiglecH- pDCs in naïve corneas. SiglecH+ pDCs also produced less NGF (74%), and NT3 (56%), (all p<0.05) than SiglecH- pDCs in DED corneas. Production of NGF and BDNF by individual pDCs in DED corneas decreased as compared with that in naïve corneas (to 70% and 69%, respectively, p<0.01).
Conclusions :
pDCs are the major source of NTs in naïve and in DED corneas, compared with cDCs and MØs, with a decrease in pDC NT production in DED corneas. This is consistent with our previous observation that production of NGF and BDNF decreased in DED corneas. SiglecH+ pDCs produced less NTs than the SiglecH- pDCs in both naïve and DED corneas.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.