The high glucose and high mannitol stimulated cells treated with anti-TLR2 (A) and anti-TLR4 (B) antibodies and stained by Cy3 and DAPI dihydrochloride. western blot analysis confirmed that the protein expression of TLR2 and TLR4 was downregulated in response to high glucose. The result of ELISA also showed that the release of IL-6 and IL-8 can be inhibited by high glucose, but these inhibitions were partly counteracted after pretreatment with anti-TLR2 and/or anti-TLR4 monoclonal antibody. The results also showed that the osmotic control did not affect the expression of TLR2, TLR4, and IL-6, 8. == Conclusions == High glucose may decrease the innate immune through TLRs in cornea epithelium. == Introduction == With rapid increases in the prevalence of diabetes mellitus (DM) worldwide, ocular complications have become a leading cause of blindness in the world [1]. In addition to abnormalities of the retina (diabetic retinopathy) and the lens (cataract), various types of corneal epithelial disorders are also relatively common in persons with DM [2]. Abnormalities of the cornea include defects in epithelium-basement membrane adhesion and altered epithelial functions such as basal cell degeneration [3], superficial punctate keratitis [4], breakdown of barrier function [5], fragility [6], recurrent erosions, and persistent epithelial defects [7]. Epithelial defect may also result in sight-threatening complications, such as stromal opacification, surface irregularity, and microbial keratitis [8]. The cornea epithelial cells constitute the first line of defense against microbial pathogens, possess the ability to detect their presence [9-11], and play an important role in inflammatory responses by releasing various mediators, such as cytokines and chemokines [12,13]. Recently, Toll-like receptors (TLRs) have proven essentialin triggering the innate immune response by recognizing pathogen-associated molecular patterns (PAMP) and stimulating SAG the activity of host immune cells against several microbial products [14]. TLRs are activated by both endogenous and exogenous agonists of microbial and nonmicrobial origin. TLR activation by their agonists triggers a signaling cascade, leading to cytokine production and initiation of an adaptive immune response [15]. TLR2 and TLR4 bind to components of the Gram-positive and -negative bacteria, respectively [15]. They are expressed in multiple cells and tissues, including in corneas. The interactionsbetween inflammation and diabetes have clear implications for the immune system. Mohammad et al. [16] reported increased TLR2 and TLR4 expression in type 1 diabetic non-obese diabetic (NOD) mice, correlating with increased nuclear factor -kappa-B (NF-B) activation in response to endotoxin, and increased proinflammatory cytokines. Using TLR2/, TLR4/knockouts, and NOD mice, Kim et al. [17] demonstrated that TLR2 senses -cell death and contributes to the instigation of autoimmune diabetes. Devaraj et al. [18] showed increased TLR2 and TLR4 expression, intracellular signaling, and TLR-mediated inflammation in monocytes SAG with significant correlation to HbA1c (A1C) levels in type 1 diabetic patients. Also, Creely et al. [19] showed increased TLR2 expression in the adipose tissue SAG of type 2 diabetic patients with strong correlates to endotoxin levels. Taken together, these observations suggest a potential role for TLR2 and TLR4 in the pathology of diabetes. However, data examining the mechanism of TLR2 and TLR4 expression and function of cornea in diabetes are unknown. Therefore, this study aimed to test the ability of high glucose, one of the key abnormalities of the diabetic condition, to induce TLRs expression in human corneal epithelium. == Methods == == Reagents and antibodies == Dulbecco’s Modified Eagle Medium (DMEM), F12, fetal bovine serum (FBS), glucose, and phosphate-buffered saline (PBS) were obtained from Invitrogen-Gibco (New York, NY). All media and cytokines used for cell culture were endotoxin minimized. Tissue culture dishes and SAG six-well chamber slides were from BD (New York, NY). Affinity purified, monoclonal, antihuman TLR2 and TLR4 and normal mouse immunoglobulin G (IgG) Rabbit polyclonal to VDAC1 were from eBioscience (San Diego, CA). The second antibody was cy3 from Beyotime Biotechnology (Beyotime, China). 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride (DAPI dihydrochloride) was used to dye the nuclear (Beyotime Biotechnology). Paired antibodies for human IL-6 and IL-8 enzyme-linked immunosorbent assays (EIA) were from BD. RNeasy Mini kit was from Qiagen (Valencia, CA) was used for RNA extraction. RNA PCR kits were from Promega (Fitchburg, WI), Ethidium bromide, DNA molecular size markers and agarose were from Gene Tech (Shanghai, China). SYBR Green PCR Kit was from Applied Biosystems (Foster City, CA). == Culture of immortalized human corneal epithelial cells == Simian virus (SV) 40 immortalized human corneal epithelial cells.