Peripheral Inflammatory Sites Research Articles

The Rheumatoid Arthritis Risk Gene AIRE Is Induced by Cytokines in Fibroblast-Like Synoviocytes and Augments the Pro-inflammatory Response.

The autoimmune regulator AIRE controls the negative selection of self-reactive T-cells as well as the induction of regulatory T-cells in the thymus by mastering the transcription and presentation of tissue restricted antigens (TRAs) in thymic cells. However, extrathymic AIRE expression of hitherto unknown clinical significance has also been reported. Genetic polymorphisms of AIRE have been associated with rheumatoid arthritis (RA), but no specific disease-mediating mechanism has been identified. Rheumatoid arthritis is characterized by a systemic immune activation and arthritis. Activated fibroblast-like synoviocytes (FLS) are key effector cells, mediating persistent inflammation, and destruction of joints. In this study, we identified AIRE as a cytokine-induced RA risk gene in RA FLS and explored its role in these pathogenic stroma cells. Using RNA interference and RNA sequencing we show that AIRE does not induce TRAs in FLS, but augments the pro-inflammatory response induced by tumor necrosis factor and interleukin-1β by promoting the transcription of a set of genes associated with systemic autoimmune disease and annotated as interferon-γ regulated genes. In particular, AIRE promoted the production and secretion of a set of chemokines, amongst them CXCL10, which have been associated with disease activity in RA. Finally, we demonstrate that AIRE is expressed in podoplanin positive FLS in the lining layer of synovial tissue from RA patients. These findings support a novel pro-inflammatory role of AIRE at peripheral inflammatory sites and provide a potential pathological mechanism for its association with RA.

Neuroimmune Interaction in the Regulation of Peripheral Opioid-Mediated Analgesia in Inflammation.

Peripheral immune cell-mediated analgesia in inflammation is an important endogenous mechanism of pain control. Opioid receptors localized on peripheral sensory nerve terminals are activated by endogenous opioid peptides released from immune cells to produce significant analgesia. Following transendothelial migration of opioid-containing leukocytes into peripheral sites of inflammation, opioid peptides are released into a harsh milieu associated with an increase in temperature, low pH, and high proteolytic activity. Together, this microenvironment has been suggested to increase the activity of opioid peptide metabolism. Therefore, the proximity of immune cells and nerve fibers may be essential to produce adequate analgesic effects. Close associations between opioid-containing immune cells and peripheral nerve terminals have been observed. However, it is not yet determined whether these immune cells actually form synaptic-like contacts with peripheral sensory terminals and/or whether they secrete opioids in a paracrine manner. This review will provide novel insight into the peripheral mechanisms of immune-derived analgesia in inflammation, in particular, the importance of direct interactions between immune cells and the peripheral nervous system.

The Ex Vivo Induction of Human CD103+CD25hi Foxp3+CD4+ and CD8+ Tregs is IL‐2 and TGF‐β1 Dependent

The expression of the integrin αE (CD103), may enhance the retention of regulatory T cells to peripheral inflammatory sites and possibly contribute to their suppressive potential. The aim of this study was to define the regulatory role of IL-2 and TGF-β1 on the CD103 expression and the optimal in vitro conditions for the induction/expansion of human CD4(+) and CD8(+) Tregs. Cord blood mononuclear cells (CBMC) were stimulated under various culture conditions, including anti-CD3, anti-CD28, IL-2 and TGF-β1. TGF-β1 and IL-2 were both required for optimal expression of CD103. In addition, TGF-β1 and IL-2 synergistically induced CD103 expression on CD8(+) T cells, whereas, only additive induced expression was noted on CD4(+) T cells. Surprisingly, CD103 expression was not dependent upon CD28 costimulation. IL-2 also played a central role in CD103 expression by CD25(hi) Foxp3+ Tregs. IL-2, TGF-β1 and anti-CD3 defined the optimal stimulatory conditions favouring the induction/expansion of both CD4(+) and CD8(+) human Tregs from naive CBMC. Thus, this study provides new insights into the regulatory role of IL-2 upon CD103 expression by human cord blood CD4(+) and CD8(+) T cells. Furthermore, it identifies the in vitro culture conditions driving the differentiation of the novel phenotype CD4(+) and CD8(+) CD103(+) CD25(hi) Foxp3+ Tregs from human CBMC.

Lipopolysaccharide upregulates the expression of corticotropin-releasing hormone via MAP kinase pathway in rat peritoneal macrophages

The stress neuropeptide, corticotropin-releasing hormone (CRH) is expressed in peripheral tissues and inflammatory sites and is implicated in the modulation of the inflammatory response in a paracrine/ autocrine manner. However, the mechanisms by which CRH expression is regulated in peripheral immune cells are unclear. In this article, we address this question by employing primary rat peritoneal macrophages treated with lipopolysaccharide (LPS). Our results showed that CRH could be detected at the mRNA and protein levels in normal peritoneal macrophages and the levels increased significantly and reached a peak at 4 h after stimulation with 100 ng/ml LPS. Furthermore, LPS-induced CRH expression was inhibited by pretreatment with PD98059, a specific MAP kinase inhibitor, in a dose-dependent fashion in which the mRNA and protein levels of CRH was decreased by 90% and 95%, respectively. In addition, pretreatment with 50 μM SB203580, a p38 MAPK inhibitor, led to the decrease of CRH mRNA level by about 41%. Altogether, these results demonstrate that LPS significantly upregulates CRH expression through MAP kinase signaling pathway in rat peritoneal macrophages.

Subsets of human CD4+ regulatory T cells express the peripheral homing receptor CXCR3

Regulatory T cells (Tregs) migrate into peripheral sites of inflammation such as allografts undergoing rejection, where they serve to suppress the immune response. In this study, we find that ∼30-40% of human CD25(hi) FOXP3(+) CD4(+) Tregs express the peripheral CXC chemokine receptor 3 (CXCR3) and that this subset has potent immunoregulatory properties. Consistently, we observed that proliferative responses as well as IFN-γ production were significantly higher using CXCR3-depleted versus undepleted responders in the mixed lymphocyte reaction, as well as following mitogen-dependent activation of T cells. Using microfluidics, we also found that CXCR3 was functional on CXCR3(pos) Tregs, in as much as chemotaxis and directional persistence towards interferon-γ-inducible protein of 10 kDa (IP-10) was significantly greater for CXCR3(pos) than CXCR3(neg) Tregs. Following activation, CXCR3-expressing CD4(+) Tregs were maintained in vitro in cell culture in the presence of the mammalian target of rapamycin (mTOR) inhibitor rapamycin, and we detected higher numbers of circulating CXCR3(+) FOXP3(+) T cells in adult and pediatric recipients of renal transplants who were treated with mTOR-inhibitor immunosuppressive therapy. Collectively, these results demonstrate that the peripheral homing receptor CXCR3 is expressed on subset(s) of circulating human Tregs and suggest a role for CXCR3 in their recruitment into peripheral sites of inflammation.

Nuclear factor (NF)-κB controls expression of the immunoregulatory glycan-binding protein galectin-1

The inflammatory response is a self-limiting process which involves the sequential activation of signaling pathways leading to the production of both pro- and anti-inflammatory mediators. Galectin-1 (Gal-1), an endogenous lectin found in peripheral lymphoid organs and inflammatory sites, elicits a broad spectrum of biological functions predominantly by acting as a potent anti-inflammatory factor and as a suppressive agent for T-cell responses. However, the molecular pathways underlying Gal-1 expression and function remain poorly understood. Here we identified a regulatory loop linking Gal-1 expression and function to NF-κB activation. NF-κB-activating stimuli increased Gal-1 expression on T cells, an effect which could be selectively prevented by inhibitors of NF-κB signaling. Accordingly, transient transfection of the p65 subunit of NF-κB was sufficient to induce high Gal-1 expression. Using in silico studies and chromatin immunoprecipitation analysis we have identified a functional NF-κB binding site within the first intron of the LGALS1 gene. In addition, our results show that exogenous Gal-1 can attenuate NF-κB activation, as shown by inhibition of IκB-α degradation induced by pro-inflammatory stimuli, higher cytoplasmic retention of p65, lower NF-κB DNA binding activity and impaired transcriptional activation of target genes. The present study suggest a novel regulatory loop by which NF-κB induces expression of Gal-1, which in turn may lead to negative control of NF-κB signaling.

Effects of Intrathecal Ketorolac on Human Experimental Pain

Nonsteroidal antiinflammatory drugs, the most commonly used analgesics, reduce pain not only by inhibiting cyclooxygenase at peripheral sites of inflammation but also by potentially inhibiting cyclooxygenase in the central nervous system, especially the spinal cord. Animal studies suggest that products of cyclooxygenase in the spinal cord do not alter pain responses to acute noxious stimuli but reduce pain and sensitization after peripheral inflammation. We used a spinal injection of small doses of the cyclooxygenase inhibitor ketorolac to survey the role of spinal cyclooxygenase in human experimental pain and hypersensitivity states. After regulatory agency approval and informed consent, we examined the effect of 2.0 mg intrathecal ketorolac in 41 healthy volunteers to acute noxious thermal stimuli in normal skin and to mechanical stimuli in skin sensitized by topical capsaicin or ultraviolet burn. We also examined the effect of intravenous ketorolac. Intrathecal ketorolac reduced hypersensitivity when it was induced by a combination of ultraviolet burn plus intermittent heat and, according to one of the two analytical strategies, when it was induced by ultraviolet burn alone. These data suggest a more limited role for spinal cord cyclooxygenase in human pain states than predicted by studies in animals.

Mast cell–derived particles deliver peripheral signals to remote lymph nodes

During infection, signals from the periphery are known to reach draining lymph nodes (DLNs), but how these molecules, such as inflammatory cytokines, traverse the significant distances involved without dilution or degradation remains unclear. We show that peripheral mast cells, upon activation, release stable submicrometer heparin-based particles containing tumor necrosis factor and other proteins. These complexes enter lymphatic vessels and rapidly traffic to the DLNs. This physiological drug delivery system facilitates communication between peripheral sites of inflammation and remote secondary lymphoid tissues.

Complement C1q chemoattracts human dendritic cells and enhances migration of mature dendritic cells to CCL19 via activation of AKT and MAPK pathways

Dendritic cells (DC) and complement are both important effectors in innate immunity, and also potent linkers between innate immunity and adaptive immunity. As key components of innate immunity, various bioactive complement components produced at the inflammatory sites have been found to be able to regulate functions of DC. It is well known that migration of DC to the peripheral inflammatory sites benefits the recognition and uptake of invading pathogens by DC as antigen-presenting cells, and DC migration to secondary lymphatic tissues benefits the priming and activation of T cells. However, up to date, little is known about the underlying signaling mechanisms for the regulation of DC migration by the multifunctional molecule C1q, the first member of classical pathway. In this study, we show that C1q mediates the chemotaxis and transendothelial migration of immature MoDC. Additionally, C1q significantly enhances the chemotaxis of LPS-induced mature DC to CCL19 via upregulation of CCR7 expression. Activation of PI3K/AKT, ERK and JNK pathways is required for the chemotaxis of immature DC to C1q, meanwhile activation of AKT and P38 pathways is required for the C1q-mediated enhancement of mature DC chemotaxis to CCL19. Therefore, our results suggest that C1q, actively produced and accumulated at the inflammatory sites, can directly chemoattract immature DC from blood to peripheral inflammatory tissues, and promotes the migration of mature DC to secondary lymph organs via activation of AKT and MAPK pathways, thus outlining new way for favoring the link of innate immunity to adaptive immunity.

Expression of the fibronectin receptor VLA-5 is regulated during human B cell differentiation and activation

We examined the expression of VLA-5, a fibronectin receptor, during human B cell development and activation. VLA-5 is a member of the integrin supergene family; VLAs are heterodimers of at least six unique alpha chains sharing a common beta chain; most are involved in cell attachment to extracellular matrix (ECM). A hypothesis of haematopoietic development is that maturing cells leave the bone marrow because of the loss of VLA-5 during differentiation. However, mature B cells are not primarily circulating cells, and the role of ECM receptors in homing to peripheral lymphoid tissue and inflammatory sites is unknown. To examine the expression of VLA-5 during B cell development, cell lines blocked at specific stages of differentiation were evaluated for their synthesis and surface expression of VLA-5 using VLA-5-specific antibody and cDNA probes. VLA-5 mRNA and surface expression were found in the pre-B cell lines, REH and Nall 1, but not in more differentiated Raji cells or in several EBV-transformed peripheral B cell lines. Circulating peripheral B lymphocytes and resting tonsillar and splenic B lymphocytes expressed no VLA-5 by FACS analysis. Interestingly, mRNA and surface expression of VLA-5 were found in SKW, a highly differentiated, IgM-secreting line. In addition, low levels of staining for VLA-5 expression could be demonstrated when tonsillar or peripheral blood B lymphocytes were stimulated by Staphylococcus aureus Cowan (SAC). All cell lines expressed VLA-3 and VLA-4, two other receptors reported to mediate fibronectin binding in some cell types. Thus, our studies provided no evidence for developmental or inflammatory regulation of these receptors. Binding studies, however, demonstrated that adherence of both pre-B REH cells and SKW cells to fibronectin was almost completely inhibited by a monoclonal antibody to VLA-5 alpha. In addition, Raji cells, which lack VLA-5 but express VLA-3 and VLA-4, showed very low level binding to fibronectin. This demonstrates that for some B lymphocytes VLA-5, rather than other possible fibronectin receptors, primarily mediates attachment to fibronectin. These data also suggest that human VLA-5 expression is regulated during B cell development, with expression at a very early stage and then again after activation. This pattern of loss and reacquisition of an ECM receptor may be relevant to normal B cell maturation and to function during immunologic injury.

The p110γ isoform of phosphatidylinositol 3-kinase regulates migration of effector CD4 T lymphocytes into peripheral inflammatory sites

The role of PI-3K in leukocyte function has been studied extensively. However, the specific role of the p110gamma isoform of PI- 3K in CD4 T lymphocyte function has yet to be defined explicitly. In this study, we report that although p110gamma does not regulate antigen-dependent CD4 T cell activation and proliferation, it plays a crucial role in regulating CD4 effector T cell migration. Naïve p110gamma(-/-) CD4 lymphocytes are phenotypically identical to their wild-type (WT) counterparts and do not exhibit any defects in TCR-mediated calcium mobilization or Erk activation. In addition, p110gamma-deficient CD4 OT.II T cells become activated and proliferate comparably with WT cells in response to antigen in vivo. Interestingly, however, antigen-experienced, p110gamma-deficient CD4 OT.II lymphocytes exhibit dramatic defects in their ability to traffic to peripheral inflammatory sites in vivo. Although antigen-activated, p110gamma-deficient CD4 T cells express P-selectin ligand, beta2 integrin, beta1 integrin, CCR4, CXCR5, and CCR7 comparably with WT cells, they exhibit impaired F-actin polarization and migration in response to stimulation ex vivo with the CCR4 ligand CCL22. These findings suggest that p110gamma regulates the migration of antigen-experienced effector CD4 T lymphocytes into inflammatory sites during adaptive immune responses in vivo.

Immune function in pregnancy: the role of corticotropin-releasing hormone

Pregnancy represents a major challenge to the maternal immune system since it has to tolerate the semi-allograft fetus. Indeed, the success of pregnancy requires an appropriate immunological interaction between the mother and the fetus. Furthermore, evidence suggests that some pregnancy complications, such as spontaneous abortions, preeclampsia and intrauterine growth restriction, are associated with abnormal maternal–fetal immune responses. Corticotropin-releasing hormone (CRH), a 41-amino acid peptide originally found in the hypothalamus, appears to have a fundamental role in the mechanisms responsible for the implantation and maintenance of human pregnancy. Reproductive CRH is a form of tissue CRH (CRH found in peripheral tissues), analogous to the immune CRH detected in peripheral inflammatory sites. Reproductive CRH has been identified in the endometrial glands, the decidualized endometrial stroma and the placental trophoblast, synctiotrophoblast and decidua. Reproductive CRH participates in various reproductive functions with an inflammatory component, where it serves as an autocrine/paracrine modulator. The immunological mechanisms contributing to the establishment and maintenance of pregnancy are not fully understood. The present article focuses on the potential roles of CRH on the physiology and pathophysiology of pregnancy and highlights its participation in implantation, early fetal immunotolerance and parturition.

Interleukin-6 is a candidate molecule that transmits inflammatory information to the CNS

Peripheral inflammation induces reactions within the CNS such as central sensitization, which is involved in the mechanism of inflammatory hyperalgesia. However, the precise mechanism of inflammatory signal transmission from the peripheral inflammatory site to the CNS is not clear. We studied the role of circulating interleukin (IL)-6 as a messenger of inflammatory information from the periphery to the CNS. In the rat model of inflammatory hyperalgesia induced by carrageenan, levels of IL-6 but not IL-1β or tumor necrosis factor alpha (TNFα) were significantly elevated in the circulating blood 3 h after an injection of carrageenan. In addition, injecting carrageenan into the hind paw evoked thermal hyperalgesia and the release of prostaglandin E 2 (PGE 2) from isolated blood vessels of the CNS ex vivo, as well as the induction of cyclooxygenase (COX)-2 and microsomal prostaglandin E synthase (mPGES)-1 and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) in vascular endothelial cells of the CNS. A prior i.p. injection of IL-6 antiserum (IL-6AS) abolished or attenuated these responses. The present results suggested that circulating IL-6 could act as a messenger of inflammatory information from peripheral inflammatory sites to the CNS and as the afferent circulating signal to the CNS to produce prostaglandins in the vascular endothelial cells of the CNS through a COX-2 dependent pathway.

Peripheral corticotropin-releasing hormone is produced in the immune and reproductive systems: actions, potential roles and clinical implications

Corticotropin-releasing hormone (CRH), the principal regulator of the hypothalamic-pituitary-adrenal axis, has been identified in various organ systems, including the immune and the female and male reproductive systems. CRH-like immunoreactivity has been reported in peripheral inflammatory sites and in a number of reproductive organs, including the ovaries, endometrial glands, decidualized endometrial stroma, placenta, decidua, and the testes. Therefore, "immune" and "reproductive" CRH are forms of "tissue" CRH; i.e., CRH found in peripheral tissues. Immune CRH plays a direct immunomodulatory role as an autocrine/paracrine mediator of inflammation. Immune CRH participates in several experimental inflammations and, in humans, in inflamed tissues from patients with autoimmune and inflammatory diseases. One of the early effects of immune CRH is the degranulation of mast cells and the release of histamine and several inflammatory cytokines. Reproductive CRH is regulating reproductive functions with an inflammatory component, such as ovulation, luteolysis, decidualization, implantation, and early maternal tolerance. Placental CRH participates in the physiology of pregnancy and the onset of labor. Circulating placental CRH is responsible for the physiologic hypercortisolism of the latter half of pregnancy. Postpartum, this hypercortisolism is followed by a transient adrenal suppression, which may explain the blues/depression and increased autoimmune phenomena observed during this period.

A Novel Function for Galectin-1 at the Crossroad of Innate and Adaptive Immunity: Galectin-1 Regulates Monocyte/Macrophage Physiology through a Nonapoptotic ERK-Dependent Pathway

Several environmental factors can differentially regulate monocyte and macrophage response patterns, resulting in the display of distinct functional phenotypes. Galectin-1, an endogenous lectin found at peripheral lymphoid organs and inflammatory sites, has shown immunoregulatory activity in vivo in experimental models of autoimmunity and cancer. Whereas compelling evidence has been accumulated regarding the effects of galectin-1 on T cell fate, limited information is available on how galectin-1 may impact other immune cell types. In the present study, we report a novel role for galectin-1 in the regulation of monocyte and macrophage physiology. Treatment with galectin-1 in vitro differentially regulates constitutive and inducible FcgammaRI expression on human monocytes and FcgammaRI-dependent phagocytosis. In addition, galectin-1 inhibits IFN-gamma-induced MHC class II (MHC-II) expression and MHC-II-dependent Ag presentation in a dose-dependent manner. These regulatory effects were also evident in mouse macrophages recruited in response to inflammatory stimuli following treatment with recombinant galectin-1 and further confirmed in galectin-1-deficient mice. Investigation of the mechanisms involved in these functions showed that galectin-1 does not affect survival of human monocytes, but rather influences FcgammaRI- and MHC-II-dependent functions through active mechanisms involving modulation of an ERK1/2-dependent pathway. Our results provide evidence of a novel unrecognized role for galectin-1 in the control of monocyte/macrophage physiology with potential implications at the crossroad of innate and adaptive immunity.

Corticotropin releasing hormone and the immune/inflammatory response

Hypothalamic corticotropin-releasing hormone (CRH) acts as the major physiologic ACTH secretagog. Moreover, CRH is distributed in the brain and spinal cord, adrenal medulla, testes, ovaries, gastrointestinal tract, pancreas, myometrium, endometrium, placenta, and diverse inflammatory sites. Immunoreactive CRH has been found in the cytoplasm of immune accessory cells (macrophages, endothelial cells, and tissue fibroblasts), and in inflammatory sites of both acute and chronic inflammation (synovial lining cell layers and blood vessels from the joints of patients with rheumatoid arthritis and osteoarthritis). Additionally, the local presence of CRH in the uveitic eyes, cytoplasm of inflammatory cells (macrophages, lymphocytes, and polymorphonuclear cells) infiltrating the iris, ciliary body, vitreous, retina, and choroid appears to be of pivotal importance in the process of experimental autoimmune uveoretinitis. Traditionally, hypothalamic CRH has been considered to act indirectly in an anti-inflammatory fashion, since the end product of the hypothalamic–pituitary–adrenal axis is cortisol, a well-known anti-inflammatory compound. However, CRH produced at peripheral inflammatory sites has been shown to participate in an autocrine/paracrine stimulation of inflammation. Thus, CRH may have a peripheral, primarily activating role on the immune system. The mechanisms of the CRH-mediated component of the immune/inflammatory response are still unclear. CRH in inflammatory sites seems to be involved in the activation of the Fas/Fas ligand system. Furthermore, locally produced embryonic and endometrial CRH plays a role in both the aseptic inflammatory process of implantation and the anti-rejection process that protects the fetus from the maternal immune system. There are two types of G-protein-coupled CRH receptors (CRH-R1 and CRH-R2). Pyrrolopyrimidine compounds, such as antalarmin, have been developed as CRH-R1 receptor antagonists. Confirming the peripheral pro-inflammatory actions of CRH, antalarmin has been shown to suppress experimental aseptic inflammation. Thus, antalarmin may represent the first in a new class of anti-inflammatory agents operating through CRH-R1. Studies of CRH genetics have provided new insights on the pathogenesis of rheumatoid arthritis in humans. DNA variation across the CRH gene-containing region has been examined in families with multiple cases of rheumatoid arthritis. Transmission Disequilibrium Test analysis showed significant association at the CRH locus.

DOCK2 is Required for Chemokine-Promoted Human T Lymphocyte Adhesion Under Shear Stress Mediated by the Integrin α4β1

The alpha4beta1 integrin is an essential adhesion molecule for recruitment of circulating lymphocytes into lymphoid organs and peripheral sites of inflammation. Chemokines stimulate alpha4beta1 adhesive activity allowing lymphocyte arrest on endothelium and subsequent diapedesis. Activation of the GTPase Rac by the guanine-nucleotide exchange factor Vav1 promoted by CXCL12 controls T lymphocyte adhesion mediated by alpha4beta1. In this study, we investigated the role of DOCK2, a lymphocyte guanine-nucleotide exchange factor also involved in Rac activation, in CXCL12-stimulated human T lymphocyte adhesion mediated by alpha4beta1. Using T cells transfected with DOCK2 mutant forms defective in Rac activation or with DOCK2 small interfering RNA, we demonstrate that DOCK2 is needed for efficient chemokine-stimulated lymphocyte attachment to VCAM-1 under shear stress. Flow chamber, soluble binding, and cell spreading assays identified the strengthening of alpha4beta1-VCAM-1 interaction, involving high affinity alpha4beta1 conformations, as the adhesion step mainly controlled by DOCK2 activity. The comparison of DOCK2 and Vav1 involvement in CXCL12-promoted Rac activation and alpha4beta1-dependent human T cell adhesion indicated a more prominent role of Vav1 than DOCK2. These results suggest that DOCK2-mediated signaling regulates chemokine-stimulated human T lymphocyte alpha4beta1 adhesive activity, and that cooperation with Vav1 might be required to induce sufficient Rac activation for efficient adhesion. In contrast, flow chamber experiments using lymph node and spleen T cells from DOCK2(-/-) mice revealed no significant alterations in CXCL12-promoted adhesion mediated by alpha4beta1, indicating that DOCK2 activity is dispensable for triggering of this adhesion in mouse T cells, and suggesting that Rac activation plays minor roles in this process.

CCR7 Mediates Inflammation-Associated Tumor Progression

Chemokine receptor 7 (CCR7) mediates leukocyte adhesion and chemotaxis from peripheral sites of inflammation through lymphatic channels to secondary lymphoid organs. Aberrant CCR7 expression has been identified on certain tumor types and been linked to pro-survival and invasive pathways. In metastatic squamous cell carcinoma of the head and neck (SCCHN), we have described the selective upregulation of functional CCR7. In this manuscript, we review our understanding of CCR7-mediated signaling in metastatic SCCHN and provide evidence for its involvement in tumor survival, invasion, and metastasis. Autocrine and paracrine CCR7 activation appears to propagate the response to the CCR7 ligands CCL19 and CCL21, which are expressed by the lymphatic endothelium, secondary lymphoid tissues, and CCR7-positive tumor cells. Based on our recent findings, the induction of CCR7 expression and the sustenance of the autocrine signaling pathway have been shown to be regulated by NF-kappaB, similar to several types of immune cells. While extending these observations to metastatic SCCHN tumor cells, our studies highlight the importance of downstream NF-kappaB mediated CCR7 signals in the progression of SCCHN malignancy.

Pharmacodynamics and pharmacokinetics of nonsteroidal anti‐inflammatory drugs in species of veterinary interest

This review summarises selected aspects of the pharmacokinetics (PK) and pharmacodynamics (PD) of nonsteroidal anti-inflammatory drugs (NSAIDs). It is not intended to be comprehensive, in that it covers neither minor species nor several important aspects of NSAID PD. The limited objective of the review is to summarise those aspects of NSAID PK and PD, which are important to an understanding of PK-PD integration and PK-PD modelling (the subject of the next review in this issue). The general features of NSAID PK are: usually good bioavailability from oral, intramuscular and subcutaneous administration routes (but with delayed absorption in horses and ruminants after oral dosing), a high degree of binding to plasma protein, low volumes of distribution, limited excretion of administered dose as parent drug in urine, marked inter-species differences in clearance and elimination half-life and ready penetration into and slow clearance from acute inflammatory exudate. The therapeutic effects of NSAIDs are exerted both locally (at peripheral inflammatory sites) and centrally. There is widespread acceptance that the principal mechanism of action (both PD and toxicodynamics) of NSAIDs at the molecular level comprises inhibition of cyclooxygenase (COX), an enzyme in the arachidonic acid cascade, which generates inflammatory mediators of the prostaglandin group. However, NSAIDs possess also many other actions at the molecular level. Two isoforms of COX have been identified. Inhibition of COX-1 is likely to account for most of the side-effects of NSAIDs (gastrointestinal irritation, renotoxicity and inhibition of blood clotting) but a minor contribution also to some of the therapeutic effects (analgesic and anti-inflammatory actions) cannot be excluded. Inhibition of COX-2 accounts for most and possibly all of the therapeutic effects of NSAIDs. Consequently, there has been an intensive search to identify and develop drugs with selectivity for inhibition of COX-2. Whole blood in vitro assays are used to investigate quantitatively the three key PD parameters (efficacy, potency and sensitivity) for NSAID inhibition of COX isoforms, providing data on COX-1:COX-2 inhibition ratios. Limited published data point to species differences in NSAID-induced COX inhibition, for both potency and potency ratios. Members of the 2-arylpropionate sub-groups of NSAIDs exist in two enantiomeric forms [R-(-) and S-(+)] and are licensed as racemic mixtures. For these drugs there are marked enantiomeric differences in PK and PD properties of individual drugs in a given species, as well as important species differences in both PK and PD properties.

Aberration of CCR7 CD8 memory T cells from patients with systemic lupus erythematosus: an inducer of T helper type 2 bias of CD4 T cells.

Chemokine receptors are important in the entry of leucocytes into the inflammatory sites of systemic lupus erythematosus (SLE). CCR7(+) and CCR7(-) memory T cells exert different functions in homing, cytokine production and cytotoxicity. To determine whether differential expression and functions of the CCR7 occur in SLE patients, we examined CCR3, CCR4, CCR5, CCR7 and CCR9 on CD4(+) and CD8(+) T cells from normal and SLE subjects. Flow cytometry, real-time quantitative reverse transcription polymerase chain reactions and Northern blotting were used to detect the expression of chemokine receptors and cytokines; a chemotaxis assay was used to detect their functions. CD4(+) T-cell stimulation with syngeneic CCR7(+) CD8(+) CD45RO(+) T cells and dendritic cells (including transwell chambers) was used to induce cytokine expression. We demonstrated that CCR7 was selectively, frequently and functionally expressed on CD8(+) (94.8%) but not on CD4(+) (16.1%) T cells from patients with active SLE, whereas this phenomenon was not seen in normal subjects and in those whose SLE was inactive. CCR7(+) CD8(+) CD45RO(+) memory T cells from patients with active SLE, themselves T helper type 2 (Th2) biased, were inducers of Th2 bias in CD4(+) T cells in a cell-cell contact manner in vitro, meanwhile, the cells from both normal subjects and those whose SLE was inactive drove CD4(+) T cells into a regulatory T-cell-derived cytokine pattern. Our findings might provide new clues to understanding the functions of CCR7(+) CD8(+) CD45RO(+)'central' memory T cells in autoimmune diseases (such as SLE). We suggest that in the case of active SLE, CCR7(+) central memory T cells were able to enter peripheral blood and inflammatory sites from secondary lymphoid organs, were continuously expressing CCR7, and interacted with dendritic cells and functioned as CCR7(-)'effector' memory T cells, which were described in normal humans.