The Chemokine Receptor CXCR4 Mediates Recruitment of CD11c⁺Conventional Dendritic Cells Into the Inflamed Murine Cornea

Abstract

PurposeThe cornea contains distinct populations of antigen-presenting cells (APCs), including conventional dendritic cells (cDCs). Little is known about the molecular mechanisms involved in cDCs homing and recruitment into the naïve and inflamed cornea. The purpose of this study was to investigate the presence of CXCR4 and its ligand CXCL12 in the murine cornea and its role in cDC migration during corneal inflammation.MethodsThe expression of CXCR4 and CXCL12 in naïve and suture-inflamed murine corneas was assessed by whole-mount staining, flow cytometry, and quantitative PCR. The role of CXCR4 in recruitment into inflamed corneas was investigated using adoptive transfer of cDCs blocked with neutralizing antibody against CXCR4.ResultsWe show the chemokine receptor CXCR4 to be expressed on 51.7% and 64.8% of total corneal CD11c+ cDCs, equating to 98.6 ± 12.5 cells/mm2 in the peripheral and 64.7 ± 10.6 cells/mm2 in the central naïve cornea, respectively. Along with a 4.5-fold increase in CXCL12 expression during inflammation (P < 0.05), infiltrating cDCs also expressed CXCR4 in both the peripheral (222.6 ± 33.3 cells/mm2; P < 0.001) and central cornea (161.9 ± 23.8 cells/mm2; P = 0.001), representing a decrease to 31.0% and 37.3% in the cornea, respectively. Further, ex vivo blockade (390.1 ± 40.1 vs. 612.1 ± 78.3; P = 0.008) and local blockade (263.5 ± 27.1 vs. 807.5 ± 179.5, P < 0.001) with anti-CXCR4 neutralizing antibody resulted in a decrease in cDCs homing into the cornea compared with cells pretreated with isotype controls.ConclusionsOur results demonstrate that corneal CXCL12 plays a direct role in CXCR4+ cDC recruitment into the cornea. The CXCR4/CXCL12 axis is therefore a potential target to modulate corneal inflammatory responses.

Intravital Multiphoton Microscopy of the Ocular Surface: Alterations in Conventional Dendritic Cell Morphology and Kinetics in Dry Eye Disease

“…Transferred cells initially reach the limbus and later migrate to peripheral and subsequently to central corneas (53,54); however, it is not yet clear if during the steady state, the resident immune cells of the cornea slowly self-regenerate through mitosis, arise from tissue resident precursors, or are recruited from the circulating blood (49,53,54). Nevertheless, upon inflammatory stimuli and increase in chemokines/cytokines in the cornea, cDCs are increased in the cornea, at least in part through recruitment from the blood (50,51,55). In this study, we observed that cDCs displayed longer track lengths in DED in the limbus, and exhibited a higher meandering index in the limbus compared with the corneal areas; thus, in line with prior studies, it might be postulated that cDCs recruited from the blood stream enter the tissue in the limbus, where they migrate to the peripheral and then the central cornea due to chemotactic gradients in the cornea during DED.…”

Melanoblasts Populate the Mouse Choroid Earlier in Development Than Previously Described

“…To quantify cell density, cells were counted using the spots tool within Imaris software with consistent thresholding for cell size in all images assessed, manually confirmed throughout the frames, and presented as cells/mm 2 , a methodology used in several studies. [25][26][27][28] In instances where the samples presented with folds resulting in the inability of optical exclusion of the RPE layer, manual counting of the cell populations through each image stack of the captured data was performed ( Supplementary Fig. 2).…”

Injection site vaccinology of a recombinant vaccinia-based vector reveals diverse innate immune signatures

“…The chemokine signatures ( Fig 4B ) are dominated by (i) CXCL12, which is made by many cell types and is strongly chemotactic for lymphocytes, (ii) CCL5 (RANTES), which is inter alia chemotactic for T cells and (iii) CXCL2, a neutrophil chemoattractant (consistent with Fig 1E ). CXCL12 and CCL5 are also involved in dendritic cell (DC) recruitment [ 151 , 152 ]. CCL2 ( Fig 4B ) is also induced by MVA [ 153 , 154 ] and is involved in DC maturation and induction of T cell immunity [ 155 ].…”