Isabel Joan Crane
University of Aberdeen
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Featured researches published by Isabel Joan Crane.
Journal of Immunology | 2000
Isabel Joan Crane; Carol Wallace; Susan McKillop-Smith; John V. Forrester
Retinal pigment epithelial (RPE) cells form part of the blood-retina barrier and have recently been shown to produce various chemokines in response to proinflammatory cytokines. As the scope of chemokine action has been shown to extend beyond the regulation of leukocyte migration, we have investigated the expression of chemokine receptors on RPE cells to determine whether they could be a target for chemokine signaling. RT-PCR analysis indicated that the predominant receptor expressed on RPE cells was CXCR4. The level of CXCR4 mRNA expression, but not cell surface expression, increased on stimulation with IL-1β or TNF-α. CXCR4 protein could be detected on the surface of 16% of the RPE cells using flow cytometry. Calcium mobilization in response to the CXCR4 ligand stromal cell-derived factor 1α (SDF-1α) indicated that the CXCR4 receptors were functional. Incubation with SDF-1α resulted in secretion of monocyte chemoattractant protein-1, IL-8, and growth-related oncogene α. RPE cells also migrated in response to SDF-1α. As SDF-1α expression by RPE cells was detected constitutively, we postulate that SDF-1–CXCR4 interactions may modulate the affects of chronic inflammation and subretinal neovascularization at the RPE site of the blood-retina barrier.
Seminars in Immunopathology | 2008
Isabel Joan Crane; Janet Liversidge
Immune-mediated inflammation in the retina is regulated by a combination of anatomical, physiological and immuno-regulatory mechanisms, referred to as the blood–retina barrier (BRB). The BRB is thought to be part of the specialised ocular microenvironment that confers protection or “immune privilege” by deviating or suppressing destructive inflammation. The barrier between the blood circulation and the retina is maintained at two separate anatomical sites. These are the endothelial cells of the inner retinal vasculature and the retinal pigment epithelial cells on Bruch’s membrane between the fenestrated choroidal vessels and the outer retina. The structure and regulation of the tight junctions forming the physical barrier are described. For leukocyte migration across the BRB to occur, changes are needed in both the leukocytes themselves and the cells forming the barrier. We review how the blood–retina barrier is compromised in various inflammatory diseases and discuss the mechanisms controlling leukocyte subset migration into the retina in uveoretinitis in more detail. In particular, we examine the relative roles of selectins and integrins in leukocyte interactions with the vascular endothelium and the pivotal role of chemokines in selective recruitment of leukocyte subsets, triggering adhesion, diapedesis and migration of inflammatory cells into the retinal tissue.
Immunology | 2000
Isabel Joan Crane; Carol Wallace; Susan McKillop-Smith; John V. Forrester
Chemokine production at the blood–retina barrier probably plays a critical role in determining the influx of tissue‐damaging cells from the circulation into the retina during inflammation. The blood–retina barrier comprises the retinal microvascular endothelium and the retinal pigment epithelium. Chemokine expression and production by human retinal microvascular endothelial cells (REC) have never been reported previously, so we examined the in vitro expression and production of monocyte chemoattractant protein‐1 (MCP‐1), regulated on activation of normal T‐cell expressed and secreted (RANTES), macrophage inflammatory protein (MIP)‐1α, MIP‐1β, interleukin (IL)‐8, epithelial cell‐derived neutrophil activating protein‐78 (ENA‐78) and growth related oncogene α (GROα) in these cells, both unstimulated and stimulated by cytokines likely to be present during the evolution of an inflammatory response. We compared this to expression and production of these chemokines in vitro in human retinal pigment epithelial cells (RPE). MCP‐1 was expressed and produced constitutively by REC but all the chemokines were produced in greater amounts upon stimulation with the proinflammatory cytokines IL‐1β and tumour necrosis factor‐α (TNF‐α). MCP‐1 and IL‐8 were produced at much higher levels than the other chemokines tested. MIP‐1α and MIP‐1β were present only at low levels, even after stimulation with IL‐1β and TNF‐α. Cytokines with greater anti‐inflammatory activity, such as IL‐4, IL‐10, IL‐13, transforming growth factor‐β (TGF‐β) and IL‐6, had little effect on chemokine production either by REC alone or after stimulation with IL‐1β and TNF‐α. RPE, although a very different cell type, showed a similar pattern of expression and production of chemokines, indicating the site‐specific nature of chemokine production. Chemokine production by REC and RPE is probably significant in selective leucocyte recruitment during the development of inflammation in the retina.
Journal of Leukocyte Biology | 2006
Isabel Joan Crane; Heping Xu; Carol Wallace; Ayyakkannu Manivannan; Matthias Mack; Janet Liversidge; Gabriel Márquez; Peter F. Sharp; John V. Forrester
Although the recruitment of T helper cell type 1 (Th1)/Th2 cells into peripheral tissues is essential for inflammation and the host response to infection, the traffic signals that enable the distinct positioning of Th1/Th2 cells are unclear. We have determined the role of CC chemokine receptor 5 (CCR5) in this using experimental autoimmune uveitis (EAU) as a model system. In EAU, Th1‐like cells are preferentially recruited into the retina across the blood‐retina barrier, partly as a result of expression of the adhesion molecules P‐selectin glycoprotein ligand 1 and lymphocyte function‐associated antigen‐1 on these cells. CD3+ T cells, infiltrating the retina, also expressed the chemokine receptor CCR5, and CCR5 ligands, macrophage‐inflammatory protein‐1α (MIP‐1α), MIP‐1β, and regulated on activation, normal T expressed and secreted (RANTES), were strongly expressed in the retina at peak EAU. Th1‐like cells, polarized in vitro, expressed high levels of CCR5. The trafficking of these CCR5+ cells was examined by tracking them after adoptive transfer in real time in vivo at an early disease stage using scanning laser ophthalmoscopy. Treatment of the cells with antibody against CCR5 prior to transfer resulted in a reduction in their infiltration into the retina. However, rolling velocity, rolling efficiency, and adherence of the cells to retinal endothelium were not reduced. CCR5 is clearly important for Th1 cell recruitment, and this study demonstrates for the first time in vivo that CCR5 may act at the level of transendothelial migration rather than at the earlier stage of rolling on the endothelium.
Journal of Immunology | 2005
Heping Xu; Ayyakkannu Manivannan; Rosemary Dawson; Isabel Joan Crane; Matthias Mack; Peter F. Sharp; Janet Liversidge
It is proposed that CCR2+ monocytes are specifically recruited to inflammatory sites, whereas CCR2− monocytes are recruited to normal tissue to become resident macrophages. Whether these subsets represent separate lineages, how differential trafficking is regulated and whether monocytes undergo further differentiation is uncertain. Using a mouse model of autoimmune uveoretinitis we examined monocyte trafficking to the inflamed retina in vivo. We show that bone marrow-derived CD11b+ F4/80− monocytes require 24 to 48 h within the circulation and lymphoid system before acquiring the CCR2+ phenotype and trafficking to the inflamed retina is enabled. This phenotype, and the capacity to traffic were lost by 72 h. Monocyte CCR2 expression followed a similar time course in normal mice indicating that differentiation to an inflammatory phenotype is a constitutive, time-limited property, independent of local inflammatory mediators. Phenotypic analysis of adoptively transferred cells indicated that circulating inflammatory monocytes also differentiate into CD11c+ and B220+ dendritic cells and F4/80+ tissue macrophages in vivo. Our data supports the hypothesis of continuous extravasation and progressive differentiation over time of inflammatory monocytes in the circulation rather than replication within the actively inflamed tissue, and supports the concept of myeloid dendritic cell differentiation from trafficking monocytes under physiological conditions in vivo.
Journal of Immunology | 2004
Heping Xu; Ayyakkannu Manivannan; Hui-Rong Jiang; Janet Liversidge; Peter F. Sharp; John V. Forrester; Isabel Joan Crane
Although there is evidence that altering the Th1/Th2 balance toward Th2 cells may be important in the resolution of Th1-type autoimmune disease, adoptive transfer of Th2 cells is not effective in protecting against Th1-type disease and may cause disease. Therefore, we examined the recruitment of Th1- and Th2-like cells into the retina in the murine autoimmune disease experimental autoimmune uveoretinitis. CD4 T cells were polarized in vitro to IFN-γ-producing Th1-like cells and non-IFN-γ-producing Th2-like cells, labeled, and adoptively transferred. Trafficking to the retina in vivo was evaluated by scanning laser ophthalmoscopy and infiltration by confocal microscopy. There were more rolling and adherent Th1-like cells and they rolled more slowly than did Th2-like cells. Th1-like cells were preferentially recruited into the retinal parenchyma at both initiation and resolution. Surface P-selectin glycoprotein ligand 1 (PSGL-1) and LFA-1 were up-regulated on both populations but were expressed at higher levels on Th1-like cells. Up-regulation of CD44 expression was higher on Th2-like cells. P-selectin, E-selectin, and ICAM-1 are up-regulated on postcapillary venules in the retina. Pretreatment of Th1-like cells with anti-PSGL-1 inhibited rolling and infiltration of Th1-like cells but not Th2-like cells, providing direct in vivo evidence for the inability of Th2 to respond to P/E-selectin despite increased expression of PSGL-1. Anti-LFA-1 pretreatment inhibited infiltration of both Th1- and Th2-like cells, but more so Th-1. We suggest that random trafficking of activated T cells (both Th1 and Th2) across the blood-retina barrier is mediated by CD44:CD44R and LFA-1:ICAM-1, whereas preferential recruitment of Th1 cells is mediated by PSGL-1:P/E-selectin.
Journal of Neuroimmunology | 2003
Heping Xu; Ayyakkannu Manivannan; Janet Liversidge; Peter F. Sharp; John V. Forrester; Isabel Joan Crane
Although activated T lymphocytes can migrate through unstimulated neural endothelium to perform immune surveillance or initiate inflammation, the precise mechanism by which this occurs is not clear. In this study, we have used intravital scanning laser ophthalmoscopy to show that circulating, activated T cells induce early changes in the retinal venules that enable T cell diapedesis in the absence of cell rolling, and without any reduction in shear stress within the venules. Concanavalin A (Con A)-activated T cells, but not naive T cells, were able to penetrate the normal blood-retinal barrier (BRB) 8-16 h after adoptive transfer. A minimum number (> or =1 x 10(5) cells/mouse) of Con A-activated T cells needed to be transferred before lymphocytes crossed the normal BRB. Cell rolling and reduction of shear stress did not occur in normal retinal venules and post-capillary venules. In contrast, in mice with experimental autoimmune uveoretinitis (EAU), in which the BRB has broken down, 45% of blast cells were rolling in retinal venules. Cell rolling correlated with significantly reduced shear stress. Both naive and Con A-activated T cells could cross the disabled barrier, with Con A-activated T cells migrating faster and in greater numbers than naive cells. Adoptive transfer of Con A-activated cells into normal recipient mice induced limited and transient breakdown of the BRB and up-regulation of ICAM-1 but not P-selectin. Pretreatment of Con A-activated cells with anti-LFA-1 significantly suppressed T cell infiltration in normal recipient mice. Our data indicate that critical to immune surveillance in the central nervous system (CNS) is the ability of activated T cells to interact with the endothelium, up-regulating ICAM-1 and inducing transient breakdown of the barrier.
Journal of Leukocyte Biology | 2002
Heping Xu; Ayyakkannu Manivannan; Janet Liversidge; Peter F. Sharp; John V. Forrester; Isabel Joan Crane
In the present study, we investigated the involvement of CD44 in leukocyte trafficking in vivo at the blood‐retinal barrier using experimental autoimmune uveoretinitis (EAU) as a model system. Leukocyte trafficking was evaluated using adoptive transfer of calcein‐AM (C‐AM)‐labeled spleen cells harvested from syngeneic mice at prepeak severity of EAU to mice at a similar stage of disease. CD44 and its ligand hyaluronan were up‐regulated in the eye during EAU. CD44‐positive leukocytes were found sticking in the retinal venules and postcapillary venules but not in the retinal arterioles nor in mesenteric vessels. Preincubation of in vitro C‐AM‐labeled leukocytes with anti‐CD44 monoclonal antibodies (mAb; IM7) or high molecular weight hyaluronic acid (HA) before transfer significantly suppressed leukocyte rolling but not sticking in retinal venules and also reduced cell infiltration in the retinal parenchyma. Administration of the HA‐specific enzyme hyaluronidase to mice before cell transfer also reduced leukocyte infiltration, suggesting that CD44‐HA interactions are involved in leukocyte recruitment in EAU. This was further supported by the observation that disease severity was reduced by administration of anti‐CD44 mAb (IM7) at the early leukocyte‐infiltration stage. Further studies also indicated that CD44 activation was associated with increased levels of apoptosis, and this may also be in part responsible for the reduction in disease severity. These findings demonstrate that CD44 is directly involved in leukocyte‐endothelial interaction in vivo and influence the trafficking of primed leukocytes to the retina and their overall survival.
Blood | 2008
Heping Xu; Ayyakkannu Manivannan; Isabel Joan Crane; Rosemary Dawson; Janet Liversidge
Using noninvasive in vivo imaging and experimental autoimmune uveoretinitis as a model, we show for the first time that the mechanisms controlling blood monocyte recirculation through peripheral and lymphoid tissues alter during inflammation. The recirculation of monocytes in mice with ocular inflammation but not controls was found to depend on the selectin CD62-ligand (CD62L) and on CD44. Not only was rolling efficiency ablated or markedly reduced in antibody-treated mice, but most of the labeled monocytes also disappeared from the circulation within seconds, anti-CD44–treated monocytes homing to the lymph nodes and anti–CD62L-treated monocytes homing to the spleen. Our data indicate that, although PSGL-1 has a partial role in the transmigration of monocytes into the inflamed retina, CD62L has a key role in regulating recruitment of monocytes to lymphoid tissue from the blood during inflammation and that CD44 is required to maintain CD62L+ inflammatory monocytes within the circulation during inflammation. This effect was systemic, because sequestered monocytes accumulated in mesenteric as well as draining cervical lymph nodes, and inflammation dependent, because depletion of circulating blood monocytes was much reduced or absent in normal mice and accumulations of adoptively transferred monocytes in the lymphoid tissues did not occur.
Journal of Leukocyte Biology | 2004
Heping Xu; Ayyakkannu Manivannan; Keith A Goatman; Hui-Rong Jiang; Janet Liversidge; Peter F. Sharp; John V. Forrester; Isabel Joan Crane
The passage of leukocytes across the blood‐retina barrier at the early stages of an inflammatory reaction is influenced by a complex series of interactions about which little is known. In particular, the relationship between hydrodynamic factors, such as shear stress and leukocyte velocity, to the adherence and subsequent extravasation of leukocytes into the retina is unclear. We have used a physiological method, scanning laser ophthalmoscopy, to track labeled leukocytes circulating in the retina, followed by confocal microscopy of retinal flatmounts to detect infiltrating cells at the early stage of experimental autoimmune uveitis. This has shown that retinal vessels are subjected to high shear stress under normal circumstances. During the inflammatory reaction, shear stress in retinal veins is reduced 24 h before leukocyte infiltration. This reduction is negatively correlated with leukocyte rolling and sticking in veins and postcapillary venules, the sites of leukocyte extravasation. Activation of vascular endothelial cells is also a prerequisite for leukocyte rolling and infiltration. In addition, antigen priming of leukocytes is influential at the early stage of inflammation, and this is seen clearly in the reduction in rolling velocity and adherence of the primed leukocytes in activated retinal venules, 9 days postimmunization.