Control of lymphocyte egress from lymph nodes through β2-adrenergic receptors

Afferent lymphatic vessels bring antigens and diverse populations of leukocytes to draining lymph nodes, whereas efferent lymphatics allow only lymphocytes and antigens to leave the nodes. Despite the fundamental importance of afferent vs. efferent lymphatics in immune response and cancer spread, the molecular characteristics of these different arms of the lymphatic vasculature are largely unknown. The objective of this work was to explore molecular differences behind the distinct functions of afferent and efferent lymphatic vessels, and find possible molecules mediating lymphocyte traffic. We used laser-capture microdissection and cell sorting to isolate lymphatic endothelial cells (LECs) from the subcapsular sinus (SS, afferent) and lymphatic sinus (LS, efferent) for transcriptional analyses. The results reveal marked differences between afferent and efferent LECs and identify molecules on lymphatic vessels. Further characterizations of Siglec-1 (CD169) and macrophage scavenger receptor 1 (MSR1/CD204), show that they are discriminatively expressed on lymphatic endothelium of the SS but not on lymphatic vasculature of the LS. In contrast, endomucin (EMCN) is present on the LS endothelium and not on lymphatic endothelium of the SS. Moreover, both murine and human MSR1 on lymphatic endothelium of the SS bind lymphocytes and in in vivo studies MSR1 regulates entrance of lymphocytes from the SS to the lymph node parenchyma. In conclusion, this paper reports surprisingly distinct molecular profiles for afferent and efferent lymphatics and a function for MSR1. These results may open avenues to explore some of the now-identified molecules as targets to manipulate the function of lymphatic vessels.lymphatics | cell traffic | lymphocytes | endothelium

Section: Discussionmentioning

confidence: 67%

Gene-expression profiling of different arms of lymphatic vasculature identifies candidates for manipulation of cell traffic

Iftakhar-E-Khuda

Fair-Mäkelä

Kukkonen-Macchi

et al. 2016

“…A recent study showed that activation of the β2 adrenergic receptor (β2AR) inhibited egress of naive CD4 and B cells and of effector OTII cells from the LN (33). This retention was mediated by an interaction of β2AR with CCR7 and CXCR4.…”

Section: Discussionmentioning

confidence: 99%

T cell-intrinsic S1PR1 regulates endogenous effector T-cell egress dynamics from lymph nodes during infection

Bénéchet

Menon

et al. 2016

Viral clearance requires effector T-cell egress from the draining lymph node (dLN). The mechanisms that regulate the complex process of effector T-cell egress from the dLN after infection are poorly understood. Here, we visualized endogenous pathogen-specific effector T-cell migration within, and from, the dLN. We used an inducible mouse model with a temporally disrupted sphingosine-1-phosphate receptor-1 (S1PR1) gene specifically in endogenous effector T cells. Early after infection, WT and S1PR1 −/− effector T cells localized exclusively within the paracortex. This localization in the paracortex by CD8 T cells was followed by intranodal migration by both WT and S1PR1−/− T cells to positions adjacent to both cortical and medullary lymphatic sinuses where the T cells exhibited intense probing behavior. However, in contrast to WT, S1PR1 −/− effector T cells failed to enter the sinuses.We demonstrate that, even when LN retention signals such as CC chemokine receptor 7 (CCR7) are down-regulated, T cell intrinsic S1PR1 is the master regulator of effector T-cell emigration from the dLN.n effective immune response depends on the large-scale, but carefully regulated, migration of T cells within and between lymphoid and peripheral tissues. This migration is tightly regulated by several factors, including the highly organized secondary lymphoid structure and the cellular expression of chemokine receptors and compartmentalized secretion of their cognate ligands (1). This balance between the anatomy and the ordered expression of cell surface and soluble proteins dictates the exquisite choreography of T-cell migration, and visualizing these dynamics of T-cell behavior in situ within the lymph nodes (LNs) is essential for understanding the mechanisms that mediate the generation of a productive antimicrobial or antitumoral immune response (1, 2). However, our understanding of the factors that regulate the anatomical program followed by endogenous antigen-specific effector T cells after an infection remains incomplete, especially with respect to the mechanisms that regulate egress kinetics of effector T cells from LN (2, 3).T-cell migration, even at steady state, is a highly regulated process (4). T-cell entry into the LN is controlled by G protein-coupled receptors (GPCRs) (3) such as CC chemokine receptor 7 (CCR7), which is also critical for the localization and retention of T cells within the LN paracortex (5, 6). Egress of naive T cells from the LN via the lymphatic vessels is regulated by the GPCR sphingosine-1-phosphate receptor-1 (S1PR1) (3) and adhesion molecules (4). S1PR1 is among four other GPCRs that bind to sphingosine-1-phosphate (S1P) with high affinity. S1PR1 is abundantly expressed in different cell types and tissues, including immune cells and endothelial cells (7). In addition to mediating lymphocyte egress, binding of S1P to S1PR1 and other receptors (S1PR2 to -5) on the cell surface initiates several signaling cascades that affect the functioning of many organ systems and control a multitude of biological ...

“…However, only CCR2 deficiency had a negative effect on BM cell migration in response to its ligand CCL2. This was in the absence of deficiencies in egress of cells from BM (7) that occur with global depletion of CCR2 (17,18). Although the importance of CCL2 as a major chemoattractant of mononuclear cells to the ischemic heart has been extensively studied, the results are often in conflict, with both administration and inhibition of CCL2 showing improvements and detrimental effects in the remodeling following MI (19,20).…”

Section: Discussionmentioning

confidence: 99%

β2-Adrenergic receptor-dependent chemokine receptor 2 expression regulates leukocyte recruitment to the heart following acute injury

Grisanti

Traynham

Repas

et al. 2016

Following cardiac injury, early immune cell responses are essential for initiating cardiac remodeling and tissue repair. We previously demonstrated the importance of β2-adrenergic receptors (β2ARs) in the regulation of immune cell localization following acute cardiac injury, with deficient leukocyte infiltration into the damaged heart. The purpose of this study was to investigate the mechanism by which immune cell-expressed β2ARs regulate leukocyte recruitment to the heart following acute cardiac injury. Chemokine receptor 2 (CCR2) expression and responsiveness to C-C motif chemokine ligand 2 (CCL2)-mediated migration were abolished in β2AR knockout (KO) bone marrow (BM), both of which were rescued by β2AR reexpression. Chimeric mice lacking immune cell-specific CCR2 expression, as well as wild-type mice administered a CCR2 antagonist, recapitulated the loss of monocyte/macrophage and neutrophil recruitment to the heart following myocardial infarction (MI) observed in mice with immune cell-specific β2AR deletion. Converse to β2AR ablation, β2AR stimulation increased CCR2 expression and migratory responsiveness to CCL2 in BM. Mechanistically, G proteindependent β2AR signaling was dispensable for these effects, whereas β-arrestin2-biased β2AR signaling was required for the regulation of CCR2 expression. Additionally, activator protein 1 (AP-1) was shown to be essential in mediating CCR2 expression in response to β2AR stimulation in both murine BM and human monocytes. Finally, reconstitution of β2ARKO BM with rescued expression of a β-arrestin-biased β2AR in vivo restored BM CCR2 expression as well as cardiac leukocyte infiltration following MI. These results demonstrate the critical role of β-arrestin2/AP-1-dependent β2AR signaling in the regulation of CCR2 expression and recruitment of leukocytes to the heart following injury.β2-adrenergic receptor | leukocyte | C-chemokine receptor 2 | cardiac injury | β-arrestin