Time course of cytokine upregulation in the lacrimal gland and presence of autoantibodies in a predisposed mouse model of Sjögren's Syndrome: The influence of sex hormones and genetic background

Abstract

Sjögren’s Syndrome (SS) is a chronic, inflammatory autoimmune disease characterized by lacrimal gland lymphocytic infiltration and epithelial cell death, as well as by the presence of serum autoantibodies. Although the symptoms of this syndrome are well characterized, patients are not diagnosed until 5–10 years into disease progression; furthermore, the early series of events leading to the initiation of SS are not well understood. In order to better understand the early events of the disease, we have been using ovariectomized (OVX) NOD.B10.H2b mice as a genetically predisposed model of SS. Previously, we have shown that removal of ovarian hormones through ovariectomy accelerated the symptoms of this disease, and in early events of SS in the lacrimal glands, lymphocytic infiltration preceded acinar cell apoptosis. To further elucidate the earlier events of this disease in the SS animal model, we investigated the expression and concentration of pro-inflammatory cytokines in the lacrimal glands as well as the presence of autoantibodies in both lacrimal glands and serum. Six weeks old NOD.B10.H2b and C57BL/10 control mice were either sham-operated, OVX, OVX and treated with 17β-estradiol (E2), or OVX and treated with dihydrotestosterone (DHT). Lacrimal glands were collected at 3, 7, 21, and 30 days after surgery and analyzed for cytokines IL-1β, TNF-α, IFN-γ, IL-10, and IL-4 gene expression by using quantitative RT-PCR and for cytokine levels using ELISA. Furthermore, anti-Ro/SSA and anti-La/SSB autoantibodies were measured in the serum and lacrimal glands supernatants using ELISA. The results of this study showed that OVX caused a significant increase in the expression and levels of the cytokines IL-1β, TNF-α, and IL-4 in the lacrimal glands of the NOD.B10.H2b mice starting at 3 days after OVX, while a significant increase of IL-10 gene expression and levels was observed only at later experimental time points. A small but significant increase in the expression of IL-1β and IL-4 was observed only at later experimental time points in the lacrimal glands of OVX C57BL/10 mice, while no significant changes in the expression of TNF-α and IL-10 were seen at any experimental times in this group. No significant differences were observed in the levels of the cytokines IL-1β, TNF-α, IL-4, and IL-10 in the lacrimal glands of the OVX C57BL/10 mice at any of the experimental times studied compared to the sham-operated group. IFN-γ was not detected in either mouse strains at the level of mRNA and protein. OVX in the NOD.B10.H2b mice also caused an increase in the levels of anti-Ro/SSA autoantibodies in the serum only, while no anti-La/SSB autoantibodies were found in the serum or lacrimal gland supernatants. Physiological doses of E2 or DHT at time of OVX prevented the upregulation of cytokines and the presence of anti-Ro/SSA autoantibodies in these animals. These results showed that a decrease in the concentrations of ovarian hormones in the genetically predisposed mice accelerated the onset of the disease by upregulating vario...

Association of Sjögren's Syndrome With Reduced Lifetime Sex Hormone Exposure: A Case–Control Study

“…Mouse models provide additional support for the protective effect of estrogen. Mice lacking aromatase have destruction of acinar cells of the major salivary glands with age (24), and normal mice that undergo ovariectomy develop apoptosis of the salivary gland epithelial cells (25). Additionally, retinoblastoma‐associated protein 48 induces apoptosis within exocrine glands, creating autoimmune lesions similar to those found in primary SS, and this process is dependent on estrogen absence (26).…”

Early Dry Eye Disease Onset in a NOD.H-2h4 Mouse Model of Sjögren's Syndrome

“…Proinflammatory marker expression correlates with the degree of inflammation in lacrimal glands of SS mouse models, including NOD strains. 53 , 54 , 94 , 95 IL-2, IL-6, TNF-α, and ICAM-1 levels were significantly higher in lacrimal glands of female and male NOD.H-2 h4 DKO than NOD.H-2 h4 mice ( Fig. 6 ).…”

Gender difference of primary Sjögren’s Syndrome in a Chinese cohort: Why do women suffer more?

“…A study [10] found enhanced B cell responses, higher levels of anti-SSA antibodies, anti-SSB antibodies, and B cell activation factor F (BAFF) in female NOD.H2(h4) mice of SS. However, another study found that anti-SSA antibodies in the serum of NOD.B10.H2(b) mice after ovariectomize (OVX) were increased, which can be antagonized by E2 or DHT replacement therapy [31]. A study found testosterone was positively correlated with ESR, serum protein, and focus score, while sex hormone-binding globulin (SHBG) was negatively correlated with anti-SSA and anti-SSB, and DHT was negatively correlated with Creactive protein (CRP) [50].…”

“…While cytokines such as the interleukin-1 receptor (IL-1R) can also act on cytokine receptors in classical hormone-producing tissues. Both estrogen and androgen can affect the antibody production of B cells [3,10,31]. Female patients with SS have been found to be de cient in androgens such as 5androstene-3beta, 5-diol, DHEA, DHT, ADT-G, and 3alpha-diol-G [32].…”