Expression of monocyte chemoattractant protein 1 in pig-to-primate cardiac xenografts

CCR2 and CCR5 chemokine receptors differentially influence the development of autoimmune diabetes in the NOD mouse

The infiltration of monocytes represents an important early event in the development of autoimmune diabetes in NOD mice. Given that chemokines are key regulators of leukocyte trafficking, we examined the requirement for the chemokine receptors beta(CC)-chemokine receptor-5 (CCR5) and beta(CC)-chemokine receptor-2 (CCR2), which recruit monocytes, in disease development in the NOD mouse. Whereas the onset of diabetes was significantly delayed in CCR2-/-NOD mice (25% at 30 weeks) compared to NOD mice (50% at 28 weeks), the pathogenesis of diabetes was accelerated in CCR5-/-NOD mice (75% at 23 weeks). The rapid development of diabetes in CCR5-/-NOD mice was associated with aggressive destructive insulitis and was accompanied by altered leukocyte migration into islets. In contrast, CCR2-/- NOD mice exhibited delayed inflammatory cell recruitment. Nevertheless, total diabetogenic splenocytes from CCR2-/-NOD and CCR5-/-NOD showed similar capability to adoptively transfer diabetes into NOD.scid recipients. Importantly, our data suggest that targeting of CCR2 may lead to therapies against Type 1 diabetes.

DNA microarray-based gene expression profiling in porcine keratocytes and corneal endothelial cells and comparative analysis associated with xeno-related rejection

Porcine to rat corneal xenotransplantation resulted in severe inflammation and rejection of the corneal stroma, whereas an allograft showed mainly endothelial cell-associated rejection. We, therefore, investigated and compared the gene expression between porcine keratocytes and corneal endothelial cells. RNA was isolated from primary cultured porcine or human keratocytes and porcine corneal endothelial cells. Gene expression was comparatively analyzed after normalization with microarray method using Platinum pig 13 K oligo chip (GenoCheck Co., Ltd., Ansan, Korea). Real-time polymerase chain reaction (PCR) was performed for C1R, CCL2, CXCL6, and HLA-A in porcine keratocytes and corneal endothelial cells. As a result, upregulated expression more than 2 folds was observed in 1,162 genes of porcine keratocytes versus porcine endothelial cells. Among the immune-regulatory genes, SEMA3C, CCL2, CXCL6, F3, HLA-A, CD97, IFI30, C1R, and G1P3 were highly expressed in porcine keratocytes, compared to porcine corneal endothelial cells or human keratocytes. When measured by real-time PCR, the expression of C1R, CCL2, and HLA-A was higher in porcine keratocytes compared to that in porcine corneal endothelial cells. In conclusion, the increased expression of C1R, CCL2, and HLA-A genes in porcine keratocytes might be responsible for the stromal rejection observed in a porcine to rat corneal xenotransplantation.

The role of chemokines and their receptors in the rejection of pig islet tissue xenografts

The mechanism by which inflammatory cells are recruited to pig islet tissue (proislet) xenografts was investigated by examining the intragraft mRNA expression of murine alpha- and beta-chemokines in CBA/H mice from days 3 to 10 post-transplant. Xenograft rejection was associated with early intragraft transcript expression for monocyte chemotactic protein-1 (MCP-1) (3 to 5 days), IP-10 (3 to 4 days) and macrophage inflammatory protein-1alpha (MIP-1alpha) (3 to 5 days) and subsequent expression of eotaxin (days 4 to 10), MIP-1beta (days 4 and 5) and regulated on activation, normal T cell expressed and secreted (RANTES) (days 4 to 6) mRNA. This pattern was consistent with the early recruitment of macrophages (MCP-1, MIP-1alpha), the influx of CD4 T cells (MCP-1, MIP-1alpha, MIP-1beta, IP-10 and RANTES) and the characteristic infiltrate of eosinophils (eotaxin and RANTES) associated with islet xenograft rejection. Inhibition of beta-chemokine signaling in CCR2-/- mice (which lack the major co-receptor for MCP-1) resulted in retarded macrophage and CD4 T cell recruitment, enhanced eosinophil influx and a minor delay in rejection, compared with wildtype mice; there was little effect on leukocyte infiltration in xenografts harvested from CCR5-/- mice (lacking the co-receptor for MIP-1alpha, MIP-1beta and RANTES). The impeded migration of leukocytes into xenografts in CCR2-/- hosts was associated with delayed intragraft expression of MCP-1 and RANTES mRNA; absence of MCP-1/CCR2-mediated signaling led to enhanced intragraft expression of MCP-1, MIP-1alpha and MIP-1beta mRNA. These findings suggest that MCP-1 plays an important role in regulating macrophage and CD4 T cell infiltration to xenograft sites via the CCR2 signaling pathway. Additional treatment of xenografted CCR2-/- transplant recipients with anti-interleukin-(IL)-4 and anti-IL-5 mAbs further delayed xenograft rejection demonstrating the potential for combined antirejection strategies in facilitating pig islet xenotransplantation.