Transgenic expression of murine chemokine decoy receptor D6 by islets reveals the role of inflammatory CC chemokines in the development of autoimmune diabetes in NOD mice.

AIMS/HYPOTHESIS: Autoimmune diabetes results from a progressive destruction of insulin-producing beta cells in the pancreatic islets by chemokine-attracted lymphocytes. Because islet cells in NOD mice produce chemokines during the development of autoimmune diabetes, we investigated the role of inflammatory CC chemokines in disease progression in these mice. METHODS: We generated a transgenic NOD mouse model that overproduces the inflammatory CC chemokine decoy receptor D6 in pancreatic islets. RESULTS: The frequency of diabetes and insulitis scores of transgenic mice were decreased significantly, compared with non-transgenic control littermates. Transgenic expression of D6 (also known as Ccbp2) did not affect systemic lymphocyte development or alter: (1) the T cell subsets such as T helper (Th)1, Th2 and T regulatory cells; or (2) antigen-presenting cells such as dendritic cells or macrophages. The percentages and numbers of T and B lymphocytes were decreased significantly in the pancreas. Activation status, autoantigen-specific proliferation and diabetogenicity of lymphocytes were also markedly reduced. CONCLUSIONS/INTERPRETATION: Inflammatory CC chemokines play a critical role in the development of autoimmune diabetes. Transgenic expression of D6 in pancreatic islets of NOD mice reduced this pathogenic process by suppressing activation of autoreactive lymphocytes and by reducing migration of lymphocytes to the pancreas.

Adverse effect on syngeneic islet transplantation by transgenic coexpression of decoy receptor 3 and heme oxygenase-1 in the islet of NOD mice.

Decoy receptor 3 (DcR3) blocks both Fas ligand- and LIGHT-induced pancreatic ß-cell damage in autoimmune diabetes. Heme oxygenase 1 (HO-1) possesses antiapoptotic, anti-inflammatory, and antioxidative effects that protect cells against various forms of attack by the immune system. Previously, we have demonstrated that transgenic islets overexpressing DcR3 or murine HO-1 (mHO-1) exhibit longer survival times than nontransgenic islets in syngeneic islet transplantation. In this study, we evaluated whether DcR3 and mHO-1 double-transgenic islets of NOD mice could provide better protective effects and achieve longer islet graft survival than DcR3 or mHO-1 single-transgenic islets after islet transplantation. We generated DcR3 and mHO-1 double-transgenic NOD mice that specifically overexpress DcR3 and HO-1 in islets. Seven hundred islets isolated from double-transgenic, single-transgenic, or nontransgenic NOD mice were syngeneically transplanted into the kidney capsules of newly diabetic female recipients. Unexpectedly, there was no significant difference in the survival time between double-transgenic or nontransgenic NOD islet grafts, and the survival times of double-transgenic NOD islet grafts were even shorter than those of DcR3 or mHO-1 single-transgenic islets. Our data indicate that transplantation of double-transgenic islets that coexpress HO-1 and DcR3 did not result in a better outcome. On the contrary, this strategy even caused an adverse effect in syngeneic islet transplantation.

Subretinal fluid from rhegmatogenous retinal detachment and blood induces the expression of ICAM-1 in the human retinal pigment epithelium (ARPE-19) in vitro.

PURPOSE: To evaluate the effect of subretinal fluid (SRF) from rhegmatogenous retinal detachment (RRD) and blood on the expression of intercellular adhesion molecule-1 (ICAM-1) in the retinal pigment epithelium. METHODS: The study included 22 patients who had experienced RRD within 1 month before the study and 14 patients with macular holes or pucker. SRF was collected during surgery to repair RRD and the vitreous was collected during vitrectomy. The SRF was cocultured with ARPE-19 cells with and without glucosamine sulphate (GS) and triamcinolone acetonide (TA). Blood from peripheral veins and blood components (red blood cells, platelet-poor plasma, and platelet-rich plasma) were also cocultured with ARPE-19 cells. Vitreous samples were cocultured with ARPE-19 cells in the control. The expression of ICAM-1 was detected and quantified by using flow cytometry. RESULTS: The expression of ICAM-1 in RPE cells was significantly higher (P<0.05) after 24-h incubation of 40% SRF with ARPE-19 cells. In addition, the expression of ICAM-1 in retinal pigment epithelium (RPE) cells significantly increased (P<0.01) when cocultured with blood and blood components. However, there were no differences (P>0.05) in ICAM-1 expression when RPE cells were cocultured with or without GS or TA. CONCLUSIONS: SRF and blood enhanced the expression of ICAM-1 in RPE cells in this study and the increased expression of ICAM-1 by SRF is not inhibited by GS or TA.