Data from: Upregulation of NLRP3 inflammasome in the tears and ocular surface of dry eye patients

Purpose: To evaluate the mRNA and protein expressions of NLRP3
inflammasome and its downstream inflammatory factors in human dry eye.
Methods: We recruited 54 patients with Sjögren’s syndrome dry eye (SSDE),
50 patients with non-Sjögren’s syndrome dry eye (NSSDE), and 46 healthy
controls. Tear film breakup time (TBUT), Schirmer I test, and fluorescein
staining (FL) were performed on all subjects. Tear samples were obtained
to analyze the inflammatory cytokine levels of IL-1β and IL-18 via
enzyme-linked immunosorbent (ELISA). Conjunctival impression cytology
(CIC) specimens were collected to detect the mRNA expression of NLRP3,
caspase-1, IL-1β, and IL-18 using quantitative RT-PCR, and the protein
expression of NLRP3 and caspase-1 by Western blotting. Results: NLRP3 mRNA
expression showed higher levels in both dry eye groups compared with
controls, with a comparably significant elevation in the SSDE group
(relative 2.47-fold upregulation, p<0.05). NLRP3 protein expression
was also increased in SSDE group (relative1.94-fold upregulation) compared
with the controls. mRNA expression of caspase-1 was significantly
upregulated in both SSDE (relative 1.44-fold upregulation, p<0.05)
and NSSDE (relative 1.32-fold upregulation, p<0.05). Procaspase-1
protein level was increased in SSDE (relative 1.84-fold upregulation) and
NSSDE (relative 1.12-fold upregulation) versus controls; and caspase-1
protein expression was also increased in SSDE (relative 1.49-fold
upregulation) and NSSDE (relative 1.17-fold upregulation) compared with
the controls. The patients with SSDE and NSSDE had higher IL-1β and IL-18
mRNA values and protein expressions than the controls did. The relative
mRNA expression of IL-1β upregulated 3.59-fold (p<0.001) in SSDE
and 2.13-fold (p<0.01) in NSSDE compared with the controls. IL-1β
protein level also showed significant upregulation in SSDE (p=0.01; vs.
controls groups). IL-18 mRNA expression levels were significantly
upregulated in the SSDE (relative 2.97-fold upregulation, p=0.001) and
NSSDE (relative 2.05-fold upregulation, p=0.001) groups compared with the
controls; tear IL-18 concentrations were also significantly increased in
the SSDE (p<0.001) and NSSDE (p<0.05) groups. Conclusions:
In the current study, we found that mRNA and protein expressions of NLRP3
inflammasome were upregulated in human dry eyes, especially in SSDE; the
downstream inflammatory factors caspase-1, IL-1β, and IL-18 were also
elevated in dry eye patients. These observations suggest the involvement
of NLRP3 inflammasome in the onset and development of the inflammation in
dry eye.