Purchase this article with an account.
Anna Marmalidou, Yihe Chen, Chunyi Shao, Takeshi Nakao, Sunil Chauhan, Reza Dana; Substance P Mediates Dysfunction of NK1R+ Tregs in Dry Eye Disease. Invest. Ophthalmol. Vis. Sci. 2017;58(8):466.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Dysfunction of regulatory T (Treg) cells has been implicated in the pathogenesis of dry eye disease (DED). Substance P (SP) is a neuropeptide involved in modulation of immune responses. Recent studies have shown the expression of SP and its receptor NK1R by immune cells. However, the role of SP in the pathogenesis of DED is mostly unknown. The aim of this study was to investigate the expression levels of SP, NK1R+ Treg frequencies, and their Foxp3 expression in a mouse model of DED.
Wild-type (WT) C57BL/6 mice were exposed to desiccating stress using a low humidity contolled environment chamber for 14 days to induce DED. Mice were then housed in a standard environment with normal humidity for additional 7 days. Expression levels of SP were quantified by real-time PCR of samples harvested from draining lymph nodes, corneas, and conjunctivas of WT (n=7) and DED (n=21) mice at days 7, 14, and 21. Frequencies of NK1R+ Tregs and their Foxp3 expression (mean fluorescein intensity, MFI) were assessed by flow cytometry analysis of NK1R+ Tregs derived from the draining lymph nodes of WT (n=6) and DED (n=18) mice at days 7, 14, and 21.
Our RT-PCR data demonstrated that expression of SP increases on day 21 in the draining lymph nodes, on days 7, 14, and 21 in the cornea, and on days 2 and 4 in the conjunctiva of mice with DED. Analysis of the draining lymph nodes of DED mice showed significantly increased frequencies of NK1R+ Tregs on day 21 (WT: 27.84% ± 2; DED: 41.9% ± 4; P < 0.05). In addition, expression of Foxp3 (a master regulator of Treg function) was significantly suppressed in NK1R+ Tregs on days 14 and 21 compared to WT mice (MFI=4027 ± 330 vs. 5363 ± 933 on day 14, and 3746 ± 473 vs. 5363 ± 933 on day 21; P < 0.05).
Our data demonstrate increased levels of SP, increased frequencies of NK1R+ Tregs, and decreased Foxp3 expression by NK1R+ Tregs in mice with DED, suggesting that high levels of SP could be associated with Treg dysfunction in DED.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only