The small tellurium-based compound SAS suppresses inflammation in human retinal pigment epithelium.

PURPOSE: Pathological angiogenesis and chronic inflammation greatly contribute to the development of choroidal neovascularization (CNV) in chorioretinal diseases involving abnormal contact between retinal pigment epithelial (RPE) and endothelial cells (ECs), associated with Bruch's membrane rupture. We explored the ability of the small organotellurium compound octa-O-bis-(R,R)-tartarate ditellurane (SAS) to mitigate inflammatory processes in human RPE cells. METHODS: Cell adhesion assays and analyses of gene and protein expression were used to examine the effect of SAS on ARPE-19 cells or primary human RPE cells that were grown alone or in an RPE-EC co-culture. RESULTS: Adhesion assays showed that SAS inhibited αv integrins expressed on RPE cells. Co-cultures of RPE cells with ECs significantly reduced the gene expression of PEDF, as compared to RPE cells cultured alone. Both SAS and the anti-αvß3 antibody LM609 significantly enhanced the production of PEDF at both mRNA and protein levels in RPE cells. RPE cells co-cultured with EC exhibited increased gene expression of CXCL5, COX1, MMP2, IGF1, and IL8, all of which are involved in both angiogenesis and inflammation. The enhanced expression of these genes was greatly suppressed by SAS, but interestingly, remained unaffected by LM609. Zymography assay showed that SAS reduced the level of MMP-2 activity in RPE cells. We also found that SAS significantly suppressed IL-1ß-induced IL-6 expression and secretion from RPE cells by reducing the protein levels of phospho-IkappaBalpha (pIκBα). CONCLUSIONS: Our results suggest that SAS is a promising anti-inflammatory agent in RPE cells, and may be an effective therapeutic approach for controlling chorioretinal diseases.

Increased CD1c+ mDC1 with mature phenotype regulated by TNFα-p38 MAPK in autoimmune ocular inflammatory disease.

In this study we investigated the role of blood CD1c(+) myeloid dendritic cells 1 (mDC1), a key mDC subtype, in patients with autoimmune uveitis. We observed a significant increase of blood CD1c(+) mDC1 in uveitis patients. The increased CD1c(+) mDC1 exhibited high HLADR expression and less antigen uptake. CD1c(+) mDC1 were divided into two subpopulations. CD1c(hi) mDC1 subpopulation showed less antigen uptake and higher HLADR expression compared to CD1c(lo) mDC1 subpopulation. Importantly, the CD1c(hi) mDC1 subpopulation was increased in uveitis patients. In vitro, mature monocyte-derived dendritic cells (MoDCs), characterized by lower levels of antigen uptake, induced more CD4(+)CD62L(-) T helper cell proliferation. The mature phenotype and function of CD1c(+) mDC1 were regulated by TNFα via a p38 MAPK-dependent pathway. These data show that alterations in the systemic immune response are involved in the pathogenesis of autoimmune uveitis and invite the therapeutic possibility of attenuating uveitis by manipulating blood CD1c(+) mDC1.

Overexpression of IL-17RC associated with ocular sarcoidosis.

BACKGROUND: Sarcoidosis is a chronic inflammatory disease with a systemic granulomatous disorder affecting multiple organs including the eye. Both CD4+ T cell and macrophage have been linked to the pathogenesis of the disease. METHODS: The expression of IL-17RC was measured using FACS,immunohistochemistry and real-time PCR. Serum level of IL-17 was detected using ELISA. RESULTS: An elevated expression of IL-17RC on CD8+ T cells in peripheral blood was found in patients with ocular sarcoidosis as compared to healthy controls. Interestingly, we found a significant increase in the serum level of IL-17 in patients with ocular sarcoidosis as compared to healthy controls, which may be responsible for the induction of IL-17RC on CD8+ cells. In addition, IL-17RC appeared only in the retinal tissue of the patient with clinically active sarcoidosis. CONCLUSIONS: Our results suggested a potential involvement of IL-17RC+CD8+ T cells in pathogenesis of ocular sarcoidosis.

The role of macrophage class a scavenger receptors in a laser-induced murine choroidal neovascularization model.

PURPOSE: Laser-induced choroidal neovascularization (CNV) is a widely used model to mimic many features of CNV resulting from wet AMD. Macrophages have been implicated in the pathogenesis of AMD. Class A scavenger receptors, scavenger receptor-A (SR-A) and macrophage receptor with collagenous domain (MARCO), are expressed on macrophages and are associated with macrophage function. The goal of this study is to examine the role of macrophage scavenger receptors in immune cell recruitment and the formation of CNV. METHODS: Laser photocoagulation was performed in wild-type and knockout mice with deletion of SR-A (SR-A(-/-)), MARCO (MARCO(-/-)), or both SR-A and MARCO double knockout (DKO). Immune cell recruitment at different time points and CNV lesions at 14 days after laser treatment were evaluated through immunostaining and confocal microscopy. Microarray analysis was performed in eyes 1 day after laser injury. RESULTS: Wild-type eyes showed higher chemokine/receptor expression compared with knockout eyes after laser injury. Scavenger receptor deficiency markedly impaired the recruitment of neutrophils and macrophages to CNV lesions at 1- and 3-days post laser injury, respectively. Significantly reduced CNV volumes were found in the eyes from scavenger receptor knockout mice compared with wild-type mice. CONCLUSIONS: The deficiency of scavenger receptors impairs the formation of CNV and immune cell recruitment. Our findings suggest a potential role for scavenger receptors in contributing to CNV formation and inflammation in AMD.

The tellurium redox immunomodulating compound AS101 inhibits IL-1ß-activated inflammation in the human retinal pigment epithelium.

PURPOSE: AS101 is a non-toxic organotellurium-IV compound with demonstrated immunomodulating activity in vitro and in vivo. Inflammatory responses are attributed to the pathophysiology of numerous ocular diseases. In this study, we wished to elucidate whether AS101 could mitigate pro-inflammatory activity in human retinal pigment epithelial (RPE) cells, which are heavily involved in ocular immune responses, induced by pro-inflammatory IL-ß activity. METHODS: Primary and transformed RPE cells treated with varying concentrations of AS101 were used in this study. Real-time PCR and ELISA assays were used to detect cytokine/chemokine mRNA expression and protein production. Western blot was used to detect changes in the NFκB pathway. Cell viability and proliferation were detected using a Vi-Cell XR cell counter. To measure the cytoprotective capacity of AS101, cell numbers were compared between cells treated with IL-1ß or lipopolysaccharide (LPS) and cells treated with IL-1ß or LPS in the presence of AS101. RESULTS: AS101 inhibited IL-1ß-induced mRNA expression and protein production of IL-6 and IL-8 in RPE cells. The viability of RPE cells treated with IL-1ß and LPS was unaffected. AS101 slightly inhibited RPE cell growth in the presence of higher levels of IL-1ß. Also, AS101 downregulated the IL-1ß activity by inhibiting the phosphorylation of p65, an NFκB subunit. CONCLUSIONS: The results demonstrate that AS101 reduces IL-1ß-induced inflammatory responses in the RPE. In previous studies, AS101 exhibited therapeutic effects in various disease models and was a safe profile in clinical trials. These results suggest that AS101 may have potent anti-inflammatory potential in the eye and confer the downregulation of RPE inflammatory responses in a pathological environment.

C5a contributes to intraocular inflammation by affecting retinal pigment epithelial cells and immune cells.

BACKGROUND: The complement activation molecule C5a has been found in the eye and is implicated in the pathogenesis of ocular inflammatory diseases. In this study, the authors sought to investigate C5a's effects on human retinal pigment epithelial (RPE) cells and peripheral blood mononuclear cells (PBMCs), and on the interaction between RPE cells and PBMCs. METHODS: Arising retinal pigment epithelia cell line-19 and PBMCs isolated from healthy donors were used in this study. Western blot, real-time PCR and cell surface receptor staining were used to detect C5a receptor expression. Real-time PCR was used to detect cytokine mRNA expression. A thiazolyl blue tetrazolium bromide assay was used to detect cell viability. Cells were stained with Annexin V and 7-aminoactinomycin D for an apoptosis assay. Cell proliferation was measured using a tritiated thymidine incorporation assay. RESULTS: C5a receptors were present on RPE cells, and receptor expression was increased by pro-inflammatory cytokines. C5a suppressed RPE cells' production of transforming growth factor ß2, an important immunosuppressive agent in the eye. In addition, the viability of RPE cells was decreased in the presence of C5a, and this effect was not due to apoptosis. C5a increased proliferation of PBMCs and upregulated their production of pro-inflammatory cytokines. Finally, C5a decreased RPE cells' ability to suppress immune cell proliferation. CONCLUSION: The results provide a direct link between complement activation and intraocular inflammation. This line of information may help to understand the mechanism of the pathogenesis of intraocular inflammatory diseases. Moreover, the authors show that a close, reciprocal interaction between the innate immune system and the adaptive immune system may be involved in the development of such diseases.

Androgen-induced PSA expression requires not only activation of AR but also endogenous IGF-I or IGF-I/PI3K/Akt signaling in human prostate cancer epithelial cells.

BACKGROUND: Prostate cancer (PrCa) risk is positively associated with levels of insulin-like growth factor I (IGF-I) and prostate specific antigen (PSA), both androgen receptor (AR) signaling target genes in PrCa cells. Although activated AR is required for androgen-induction of expression of both genes, effects of the IGF-I signaling pathways on the androgen-induction of PSA have not been studied. METHODS: Human prostate stromal and epithelial cancer cells were treated alone or in coculture with steroid hormone and/or inhibitors. Gene or protein expression was analyzed by real time RT-PCR or Western blotting of lysates, nuclear extracts, or immunoprecipitated products. RESULTS: In PrCa epithelial cells, endogenous IGF-I, significantly induced by R1881, was required for R1881-induction of PSA. Increased IGF-I correlated with accumulation of cytoplasmic dephospho ß-catenin (CPDP ß-catenin), a co-activator of AR signaling. Exogenous IGF-I enhanced R1881-induced PSA and accumulation of CPDP ß-catenin in LAPC-4 cells. Functional depletion of IGF-I or IGF-I receptor diminished PSA induction. Induction of IGF-I reached a plateau while PSA consecutively increased. Inhibiting PI3K abolished R1881-induced Akt phosphorylation, CPDP and nuclear ß-catenin and nuclear association of AR/ß-catenin, consequently abrogating R1881-induced expression of IGF-I and/or PSA. CONCLUSIONS: By integrating androgen, IGF-I and ß-catenin signaling pathways, these data reveal that androgen-induced PSA expression requires activation of AR and endogenous IGF-I or IGF-I/PI3K/Akt signaling, suggesting a positive feedback cycle for increased production of PSA associated with PrCa.