High-Mobility Group Box 1 in Dry Eye Inflammation.
ABSTRACT: To determine high-mobility group box 1 (HMGB1) expression during experimental dry eye (EDE) and dry eye-like culture conditions and elucidate its role in corneal dry eye-related inflammation.EDE was induced in 8- to 12-week-old C57BL/6 mice. Corneal tissue sections and lysates from EDE and untreated mice were evaluated for HMGB1 expression by immunostaining and quantitative real-time PCR (qPCR). For in vitro studies, human corneal epithelial cells (HCEC) were treated with hyperosmolar media, toll-like receptor (TLR) agonists, or proinflammatory cytokines to determine HMGB1 expression. HCEC were also treated with human recombinant HMGB1 (hrHMGB1) alone or in combination with inflammatory stimuli, and TNF?, IL-6, and IL-8 expression evaluated by qPCR and ELISA. Nuclear factor-?B (NF-?B) p65 nuclear translocation was determined by immunostaining.EDE mice had higher corneal HMGB1 RNA and protein expression compared to untreated animals. In HCEC, hyperosmolar stress and TNF? treatment stimulated HMGB1 production and secretion into culture supernatants. However, in vitro stimulation with hrHMGB1 did not induce secretion of TNF?, IL-6, or IL-8 or NF-?B p65 nuclear translocation. In addition, the inflammatory response elicited by TLR agonists fibroblast-stimulating lipopeptide-1 and lipopolysaccharide was not enhanced by hrHMGB1 treatment.HMGB1 expression was enhanced by dry eye conditions in vivo as well as in vitro, during hyperosmolar stress and cytokine exposure, suggesting an important role for HMGB1 in dry eye disease. However, no direct inflammatory effect was observed with HMGB1 treatment. Therefore, under these conditions, HMGB1 does not contribute directly to dry eye-induced inflammation and its function at the ocular surface needs to be explored further.
Project description:Dry eye disease (DED) is a multifactorial disease associated with ocular surface inflammation. Toll-like receptors (TLRs) are integral in the initiation of inflammatory signaling. Therefore, we evaluated the effect of TLR-deficiency on dry eye-related ocular surface damage and inflammation using a mouse model of experimental dry eye (EDE).C57BL/6 wild-type (WT), MyD88-/-, and IL-1R-/- mice were exposed to EDE conditions for 5 days. Tear production was measured by phenol red thread test and ocular surface damage assessed with fluorescein staining. Corneal homogenates were obtained for matrix metalloproteinase (MMP) and cytokine expression analysis by Luminex assay and quantitative PCR. In addition, whole eyes and eyelids were dissected and goblet cells and Meibomian glands were imaged, respectively.Following 5 days of EDE, WT mice had extensive ocular surface staining, while MyD88-/- mice had no increased staining above non-EDE conditions. Similarly, MyD88-/- mice did not have increased corneal MMP-2, 3, or 8 concentrations, as seen with WT mice. MyD88-deficiency also resulted in decreased corneal cytokine levels. In addition, MyD88-/- mice had significantly lower conjunctival goblet cell counts compared with both WT (EDE) and IL-1R-/- (non-EDE) mice. However, there was no difference in Meibomian gland morphology between WT, IL-1R-/-, and MyD88-/- mice.These studies demonstrate the importance of TLR signaling in dry eye development. Mice lacking TLR signaling, MyD88-/-, were protected from EDE-induced ocular surface damage and inflammatory mediator expression, warranting further investigation into TLR inhibition as a potential therapeutic for DED.
Project description:The aim of this study was to assess the anti-inflammatory and anti-apoptotic effects of KIOM-2015EW, the hot-water extract of maple leaves in hyperosmolar stress (HOS)-induced human corneal epithelial cells (HCECs). HCECs were exposed to hyperosmolar medium and exposed to KIOM-2015EW with or without the hyperosmolar media. Tumor necrosis factor (TNF)-?, interleukin (IL)-1?, and IL-6 production and apoptosis were observed, and the activation of mitogen-activated protein kinases (MAPKs) including extracellular signal regulated kinase (ERK), p38 and c-JUN N-terminal kinase (JNK) signaling and nuclear factor (NF)-?B was confirmed. Compared to isomolar medium, the induction of cell cytotoxicity significantly increased in HCECs exposed to hyperosmolar medium in a time-dependent manner. KIOM-2015EW-treatment significantly reduced the mRNA and protein expression of pro-inflammatory mediators and apoptosis. KIOM-2015EW-treatment inhibited HOS-induced MAPK signaling activation. Additionally, the HOS-induced increase in NF-?B phosphorylation was attenuated by KIOM-2015EW. The results demonstrated that KIOM-2015EW protects the ocular surface by suppressing inflammation in dry eye disease, and suggest that KIOM-2015EW may be used to treat several ocular surface diseases where inflammation plays a key role.
Project description:The aim of the present study was to investigate the anti-inflammatory effects of glycine thymosin ?4 (Gly-T?4) eye drops, and to compare the efficacy of topical Gly-T?4 with Cyclosporine A (CsA) in a mouse model of experimental dry eye (EDE). Eye drops consisting of balanced salt solution (BSS), 0.1% Gly-T?4 or 0.05% CsA were used for treatment of EDE. Tear volume, tear film break-up time and corneal staining scores were measured after 7 and 14 days. Periodic acid-Schiff staining for conjunctival gobleT cells, TUNEL assay for corneal apoptotic positive cells, multiplex immunobead assay for interleukin (IL)-1?, IL-6, tumor necrosis factor-? and interferon-? levels, and flow cytometry for CD4+/CCR5+ T cells were performed after 14 days. All clinical parameters showed improvement in the Gly-T?4 and CsA groups (all P<0.05). Significantly increased conjunctival gobleT cells and decreased corneal TUNEL positive cells were observed in the Gly-T?4 and CsA groups. The Gly-T?4 and CsA treated groups showed significantly reduced inflammatory cytokine levels and T cells in the conjunctiva compared with the EDE and BSS groups (all P<0.05). However, there were no significant differences observed in the inflammatory and clinical parameters between the Gly-T?4 and CsA treatment groups. Topical application of 0.1% Gly-T?4 significantly reduced inflammation on the ocular surface, as well as clinical parameters of EDE, with a similar efficacy to that of 0.05% CsA emulsions, suggesting that Gly-T?4 eye drops may be used as a therapeutic agent for treatment of dry eye disease.
Project description:Tear film hyperosmolarity and anterior ocular inflammation are two clinical signs that may be indicative of dry eye disease (DED). This condition can cause pathological and functional changes to the anterior ocular surface tissues. A contributing factor may be dysfunctional aquaporin 5 (AQP5) water channels as they are the AQP subtype that expressed in the corneal epithelium and contribute to fluid efflux needed for corneal function. We determined if described hyperosmolarity-induced increases in proinflammatory cytokine expression and cell death are mediated through AQP5 upregulation and JNK1/2 MAPK signaling activation in both primary human corneal epithelial cells (HCECs), and in a HCEC line. Real time RT-PCR identified rises in IL-1?, IL-6, IL-8, TNF-?, caspase-1, and AQP5 mRNA levels upon step increases in osmolarity up to 550?mOsm. Western blot analysis and the TUNEL assay identified corresponding rises in AQP5 and p-JNK1/2 protein expression and cell death respectively. JNK1/2 inhibition with SP600125, or siRNA AQP5 gene silencing reduced hypertonic-induced rises in proinflammatory cytokine expression and cell death. Taken together, hypertonicity-induced AQP5 upregulation leads to increases in proinflammatory cytokine expression and cell death through JNK1/2 MAPK activation. These results suggest that drug targeting AQP5 upregulation may be a therapeutic option in DED management.
Project description:<h4>Purpose</h4>Extracellular high mobility group box 1 (HMGB1) acts as a damage associated molecular pattern molecule through the Toll-like receptor to promote autoreactive B cell activation, which may be involved in the pathogenesis of Sj?gren's syndrome. The aim of this study was to investigate the effect of subconjunctival administration of anti-HMGB1 on dry eye in a mouse model of Sj?gren's syndrome.<h4>Methods</h4>Ten weeks-old NOD.B10.H2b mice were subconjunctivally injected with 0.02 to 2 ?g of anti-HMGB1 antibodies or PBS twice a week for two consecutive weeks. Tear volume and corneal staining scores were measured and compared between before- and after-treatment. Goblet cell density was counted in PAS stained forniceal conjunctiva and inflammatory foci score (>50 cells/focus) was measured in extraorbital glands. Flow cytometry was performed to evaluate the changes in BrdU+ cells, IL-17-, IL-10-, or IFN?-secreting cells, functional B cells, and IL-22 secreting innate lymphoid cells (ILC3s) in cervical lymph nodes. The level of IL-22 in intraorbital glands was measured by ELISA.<h4>Results</h4>Injection of 2 ?g or 0.02 ?g anti-HMGB1 attenuated corneal epithelial erosions and increased tear secretion (p<0.05). Goblet cell density was increased in 0.2 ?g and 2 ?g anti-HMGB1-treated-mice with marginal significance. The inflammatory foci score, and the number of BrdU+ cells, IL-17-, IL-10-, IFN?-secreting cells, and functional B cells did not significantly change following anti-HMGB1 treatment. Surprisingly, the percentage of ILC3s was significantly increased in the draining lymph nodes (p<0.05), and the expression of IL-22 was significantly increased in the intraorbital glands (p<0.05) after administration of 2 ?g anti-HMGB1.<h4>Conclusion</h4>This study shows that subconjunctival administration of anti-HMGB1 attenuates clinical manifestations of dry eye. The improvement of dry eye may involve an increase of ILC3s, rather than modulation of B or plasma cells, as shown using a mouse model of Sj?gren's syndrome.
Project description:PURPOSE: Inflammation plays an important role in dry eye syndrome. In this study, inflammatory cytokine expression on the ocular surface in the Botulium toxin B (BTX-B) induced mouse dry eye model was investigated. METHODS: CBA/J mice received an injection of saline or 20 milliunits (mU) of BTX-B into the lacrimal gland. Tear production and corneal fluorescein staining were evaluated in all groups before injection and at 3 time points after. The pro-inflammatory cytokines macrophage inhibitory factor (MIF), interleukin-1beta (IL-1 beta), tumor necrosis factor-alpha (TNF- alpha) and interleukin-6 (IL-6) in conjunctival and corneal epithelium were evaluated by real time quantitative PCR and immunohistochemistry. RESULTS: BTX-B injected mice showed significantly decreased aqueous tear production and increased corneal fluorescein staining at the 1 week and 2 week time points compared with normal control and saline-injected mice. The BTX-B injected mice mRNA expression levels of TNF-alpha and IL-1beta from conjunctival and corneal epithelial cells increased significantly at two early time points comparing with that of normal and saline injected mice, but IL-1beta returned to normal levels at the 4 week time point. Saline injected mice showed no difference in mRNA expression of TNF-alpha, IL-1beta, MIF, and IL-6 on the ocular surface tissue at all time points. Immunohistochemistry confirmed these findings. CONCLUSIONS: BTX-B induced mouse model showed decreased aqueous tear production, increased corneal fluorescein staining, and TNF-alpha and IL-1beta increased expression on the ocular surface within one month. The patterns seen appeared to mimic those in humans with non-Sjögren's syndrome keratoconjunctivitis sicca (NS-KCS).
Project description:Tear hyperosmolarity is a key event in dry eye. In this work, we analyzed whether hyperosmolar challenge induces ATP release on the ocular surface. Moreover, as extracellular ATP can activate P2X7 receptor, the changes in P2X7 protein levels and its involvement in pathological process triggered by hypertonic treatment were also examined. High-performance liquid chromatography analysis revealed that ATP levels significantly increased in human corneal and conjunctival epithelial cells exposed to hyperosmotic challenge as well as in dry eye patients as compared to control subjects. A significant reduction in cell viability was detected after hyperosmolar treatment, indicating that the rise in ATP release was mainly due to cell lysis/death. Additionally, vesicular nucleotide transporter was identified in both cell lines and their protein expression was upregulated in hypertonic media. P2X7 receptor truncated form together with the full-length form was identified in both cell lines, and experiments using specific antagonist and agonist for P2X7 indicated that this receptor did not mediate cell death induced by hyperosmolar stress. In conclusion, hyperosmotic stress induces ATP release. Extracellular ATP can activate P2X7 receptor leading to cytotoxicity in many cells/tissues; however, this does not occur in human corneal and conjunctival epithelial cells. In these cells, the presence of P2X7 receptor truncated form together with the full-length form hinders a P2X7 apoptotic behavior on the ocular surface.
Project description:Dry eye syndrome is commonly thought of as an inflammatory disease, and we have previously presented data showing the effectiveness of topical TNF-? blocker agents for the treatment of this condition. The purpose of this study was to investigate the effectiveness of the TNF-? blocking agent HL036337 compared to cyclosporine A for the treatment of dry eye induced inflammation in order to establish whether HL036337 represents a more effective method for suppressing inflammation. The efficacy of HL036337 and cyclosporine A was determined using an experimental murine dry eye model.The TNF-? blocker HL036337 is a modified form of TNF receptor I. Using dry eye induced C57BL/6 mice (n = 45), corneal erosion was measured at day 4 and 7 after topical treatment with cyclosporine A or HL036337. To determine the effective treatment dose, 0.25, 0.5, 1, 2.5, and 5 mg/mL of HL036337 were topically administered twice per day to dry eye induced murine corneas for 1 week.The optimal concentration of the TNF-? blocker HL036337 for treatment of dry eye induced corneal erosion was determined to be 1 mg/mL. Dry eye induced corneal erosion was improved after 1 week with topically applied cyclosporine A and HL036337 at 1 mg/mL.HL036337 administered topically at 1 mg/mL effectively improved corneal erosion induced by dry eye. This finding may also suggest that inhibition of TNF-? can improve dry eye syndrome.
Project description:AIM:To investigate whether high-mobility group box 1 (HMGB1) Boxb exacerbates BALB/c mice corneal immune responses and inflammatory through the Toll-like receptor 4 (TLR4)/myeloid differentiation primary response 88 (MyD88)-dependent signaling pathway in Aspergillus fumigatus (A. fumigatus) keratitis. METHODS:The mice corneas were pretreated with phosphate buffer saline (PBS), Boxb before A. fumigatus infection. The abdominal cavity extracted macrophages were pretreated with PBS, Boxb, TLR4 inhibitor (CLI-095), Dimethyl sulfoxide (DMSO) separately before A. fumigatus hyphae stimulation. HMGB1 was detected in normal and infected mice corneas and macrophages by real-time reverse transcriptase polymerase chain reaction (RT-PCR), the TLR4, MyD88, interleukin-1? (IL-1?), tumor necrosis factor-? (TNF-?) were detected by Western blot and PCR. RESULTS:In BALB/c mice corneas, the expressions of TLR4, HMGB1, IL-1?, TNF-? were increased after A. fumigatus infection. While pretreatment with Boxb significantly increased the expressions of TLR4, HMGB1, MyD88, IL-1?, TNF-? compared with PBS control after infection. In BALB/c mice abdominal cavity extracted macrophages, pretreatment with Boxb increased the expressions of TLR4, HMGB1, MyD88, IL-1?, TNF-?, while pretreatment with CLI-095 and Boxb significantly decreased the expressions of TLR4, HMGB1, MyD88, IL-1?, TNF-?. CONCLUSION:In A. fumigatus keratitis, Boxb play a pro-inflammatory role in corneal anti-fungi immune response through the HMGB1-TLR4-MyD88 signal pathway.
Project description:Dry eye disease (DED) is a multifactorial ocular surface disorder affecting millions of individuals worldwide. Inflammation has been associated with dry eye and anti-inflammatory drugs are now being targeted as the alternate therapeutic approach for dry eye condition. In this study, we have explored the anti-inflammatory and autophagy modulating effect of chloroquine (CQ) in human corneal epithelial and human corneal fibroblasts cells exposed to desiccation stress, (an in-vitro model for DED). Gene and protein expression profiling of inflammatory and autophagy related molecular factors were analyzed in HCE-T and primary HCF cells exposed to desiccation stress with and without CQ treatment. HCE-T and HCF cells exposed to desiccation stress exhibited increased levels of activated p65, TNF-?, MCP-1, MMP-9, and IL-6. Further, treatment with CQ decreased the levels of active p65, TNF-?, MCP-1, and MMP-9 in cells underdesiccation stress. Increased levels of LC3B and LAMP1 markers in HCE-T cells exposed to desiccation stress suggest activation of autophagy and the addition of CQ did not alter these levels. Changes in the phosphorylation levels of MAPKinase and mTOR pathway proteins were found in HCE-T cells under desiccation stress with or without CQ treatment. Taken together, the data suggests that HCE-T cells under desiccation stress showed NF?B mediated inflammation, which was rescued through the anti-inflammatory effect of CQ without altering the autophagy flux. Therefore, CQ may be used as an alternate therapeutic management for dry eye condition.