Skin reactivity and local cell recruitment in human atopic and nonatopic subjects by CCL2/MCP-1 and CCL3/MIP-1alpha

Biphasic calcium phosphate recruits Tregs to promote bone regeneration

The use of bone substitute materials is crucial for the healing of large bone defects. Immune response induced by bone substitute materials is essential in bone regeneration. Prior research has mainly concentrated on innate immune cells, such as macrophages. Existing research suggests that T lymphocytes, as adaptive immune cells, play an indispensable role in bone regeneration. However, the mechanisms governing T cell recruitment and specific subsets that are essential for bone regeneration remain unclear. This study demonstrates that CD4+ T cells are indispensable for ectopic osteogenesis by biphasic calcium phosphate (BCP). Subsequently, the recruitment of CD4+ T cells is closely associated with the activation of calcium channels in macrophages by BCP to release chemokines Ccl3 and Ccl17. Finally, these recruited CD4+ T cells are predominantly Tregs, which play a significant role in ectopic osteogenesis by BCP. These findings not only shed light on the immune-regenerative process after bone substitute material implantation but also establish a theoretical basis for developing bone substitute materials for promoting bone tissue regeneration. STATEMENT OF SIGNIFICANCE: Bone substitute material implantation is essential in the healing of large bone defects. Existing research suggests that T lymphocytes are instrumental in bone regeneration. However, the specific mechanisms governing T cell recruitment and specific subsets that are essential for bone regeneration remain unclear. In this study, we demonstrate that activation of calcium channels in macrophages by biphasic calcium phosphate (BCP) causes them to release the chemokines Ccl3 and Ccl17 to recruit CD4+ T cells, predominantly Tregs, which play a crucial role in ectopic osteogenesis by BCP. Our findings provide a theoretical foundation for developing bone substitute material for bone tissue regeneration.

Granulocyte development, tissue recruitment, and function during allergic inflammation

Granulocytes provide a fast innate response to pathogens and allergens. In allergy and anti-helminth immunity, epithelial cells of damaged barriers release alarmins like IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) but also chemokines like CXCL1 or CCL11 to promote cell recruitment and inflammation. In addition, mast cells positioned at barrier tissue sites also quickly release mediators upon specifically sensing antigens through IgE bound to FcεR1 on their surface. Released mediators induce the recruitment of different granulocytes in a timely ordered manner. First, neutrophils extravasate from the blood vasculature to the side of alarmin release and promote a potent inflammatory response. Alarmins and activated mast cells further promote activation of ILC2s and recruitment of basophils and eosinophils, which inhibit neutrophil recruitment and enhance tissue type 2 immunity. In addition to their potent pro-inflammatory effector functions, granulocytes can also contribute to termination and resolution of inflammation. Here, we summarize the development and tissue recruitment of granulocyte subsets, and describe general effector functions and aspects of their increasingly appreciated role in limiting tissue damage. We further discuss targeting approaches for therapeutic interventions in allergic disorders.

Etiology of end-stage liver cirrhosis impacts hepatic natural killer cell heterogenicity

The natural killer (NK) cell population is a critical component of the innate immune compartment of the liver, and its functions are deeply affected by the surrounding environment. In the late stage of fibrosis, NK cells become dysfunctional, but the influence of disease etiology on NK cell behavior during cirrhosis remains unclear. Using single-cell RNA sequencing (scRNA-seq), we characterized the hepatic NK cells from end-stage cirrhotic livers from subjects with non-alcoholic steatohepatitis (NASH), chronic hepatitis C infection (HCV) and primary sclerosing cholangitis (PSC). Here, we show that although NK cells shared similar dysfunctions, the disease etiology impacts hepatic NK cell heterogeneity. Therapeutical strategies targeting NK cells for the prevention or treatment of fibrosis should consider liver disease etiology in their design.

Skin-homing basophils and beyond

Basophils have been implicated in type 2 inflammation and numerous disorders in the skin such as helminth infection, atopic dermatitis, and urticaria. Although similar in form and function to tissue-resident mast cells, classical studies on basophils have centered on those from the hematopoietic compartment. However, increasing studies in tissues like the skin demonstrate that basophils may take on particular characteristics by responding to unique developmental, chemotactic, and activation cues. Herein, we highlight how recent studies in barrier immunology suggest the presence of skin-homing basophils that harbor a unique identity in terms of phenotype, function, and motility. These concepts may uniquely inform how basophils contribute to diseases at multiple epithelial surfaces and our ability to therapeutically target the innate immune system in disease.

Comparative study of 1064 nm nanosecond, 1064 nm picosecond, 755 nm, and 595 nm lasers for tattoo removal: An essential role by macrophage

OBJECTIVES

Tattoo removal is in high demand, and many types of lasers can be used for tattoo removal. Macrophages play an important role in the persistence of tattoos. However, comparative studies of the efficacy of tattoo removal with different lasers versus the relationship between the destruction of pigment particles or recruitment of macrophages after laser treatment are lacking.

MATERIALS AND METHODS

Tattoo models were established on the rat dorsal surface and randomly treated with 1064 nm nanosecond, 1064 nm picosecond, 755 nm, and 595 nm lasers for one session. Clinical photographic evaluation, melanin index, hematoxylin and eosin staining, identification of macrophages by CD68 staining, and transmission electron microscopy were conducted at different time points.

RESULTS

Regardless of the pulse duration, all lasers included were effective for the removal of black tattoos, with 1064 nm lasers having the best efficacy, followed by 755 and 595 nm lasers. The diameter of the pigment particles and recruitment of dermal macrophages correlated with the efficacy of tattoo removal.

CONCLUSIONS

In this study, the 1064 nm lasers were found to be the most effective for black tattoo removal. However, there was no significant difference between the 1064 nm picosecond and the nanosecond lasers. Macrophage recruitment plays an essential role in pigment metabolism during laser-tattoo removal.

Fibroblasts as confederates of the immune system

Fibroblastic stromal cells are as diverse, in origin and function, as the niches they fashion in the mammalian body. This cellular variety impacts the spectrum of responses elicited by the immune system. Fibroblast influence on the immune system keeps evolving our perspective on fibroblast roles and functions beyond just a passive structural part of organs. This review discusses the foundations of fibroblastic stromal-immune crosstalk, under the scope of stromal heterogeneity as a basis for tissue-specific tutoring of the immune system. Focusing on the skin as a relevant immunological organ, we detail the complex interactions between distinct fibroblast populations and immune cells that occur during homeostasis, injury repair, scarring, and disease. We further review the relevance of fibroblastic stromal cell heterogeneity and how this heterogeneity is central to regulate the immune system from its inception during embryonic development into adulthood.

Epidermal activation of Hedgehog signaling establishes an immunosuppressive microenvironment in basal cell carcinoma by modulating skin immunity

Genetic activation of hedgehog/glioma‐associated oncogene homolog (HH/GLI) signaling causes basal cell carcinoma (BCC), a very frequent nonmelanoma skin cancer. Small molecule targeting of the essential HH effector Smoothened (SMO) has proven an effective therapy of BCC, though the frequent development of drug resistance poses major challenges to anti‐HH treatments. In light of recent breakthroughs in cancer immunotherapy, we analyzed the possible immunosuppressive mechanisms in HH/GLI‐induced BCC in detail. Using a genetic mouse model of BCC, we identified profound differences in the infiltration of BCC lesions with cells of the adaptive and innate immune system. Epidermal activation of Hh/Gli signaling led to an accumulation of immunosuppressive regulatory T cells, and to an increased expression of immune checkpoint molecules including programmed death (PD)‐1/PD‐ligand 1. Anti‐PD‐1 monotherapy, however, did not reduce tumor growth, presumably due to the lack of immunogenic mutations in common BCC mouse models, as shown by whole‐exome sequencing. BCC lesions also displayed a marked infiltration with neutrophils, the depletion of which unexpectedly promoted BCC growth. The study provides a comprehensive survey of and novel insights into the immune status of murine BCC and serves as a basis for the design of efficacious rational combination treatments. This study also underlines the need for predictive immunogenic mouse models of BCC to evaluate the efficacy of immunotherapeutic strategies in vivo.

Eosinophil accumulation predicts response to melanoma treatment with immune checkpoint inhibitors

Eosinophils have been identified as a prognostic marker in immunotherapy of melanoma and suggested to contribute to anti-tumor host defense. However, the influence of immune checkpoint inhibitors (ICI) on the eosinophil population is poorly studied. Here, we applied routine laboratory tests, multicolor flow cytometry, RNA microarray analysis, and bio-plex assay to analyze circulating eosinophils and related serum inflammatory factors in 32 patients treated with pembrolizumab or the combination of nivolumab and ipilimumab. We demonstrated that clinical responses to ICI treatment were associated with an eosinophil accumulation in the peripheral blood. Moreover, immunotherapy led to the alteration of the eosinophil genetic and activation profile. Elevated serum concentrations of IL-16 during ICI treatment were found to be associated with increased frequencies of eosinophils in the peripheral blood. Using immunohistochemistry, we observed an enhanced eosinophil degranulation and a positive correlation between eosinophil and CD8⁺ T cell infiltration of tumor tissues from melanoma patients treated with ICI. Our findings highlight additional mechanisms of ICI effects and suggest the level of eosinophils as a novel predictive marker for melanoma patients who may benefit from this immunotherapy.

New therapeutic strategies for IPF: Based on the "phagocytosis-secretion-immunization" network regulation mechanism of pulmonary macrophages

Pulmonary fibrosis is a chronic and progressive interstitial lung disease of known and unknown etiology. Over the past decades, macrophages have been recognized to play a significant role in IPF pathogenesis. According to their anatomical loci, macrophages can be divided to alveolar macrophages (AMs) subtypes and interstitial macrophages subtypes (IMs) with different responsibility in the damage defense response. Depending on diverse chemokines and cytokines in local microenvironments, macrophages can be induced and polarized to either classically activated (M1) or alternatively activated (M2) phenotypes in different stages of immunity. Therefore, we hypothesize that there is a "phagocytosis-secretion-immunization" network regulation of pulmonary macrophages related to a number of chemokines and cytokines. In this paper, we summarize and discuss the role of chemokines and cytokines involved in the "phagocytosis-secretion-immunization" network regulation mechanism of pulmonary macrophages, pointing toward novel therapeutic approaches based on the network target regulation in the field. Therapeutic strategies focused on modifying the chemokines, cytokines and the network are promising for the pharmacotherapy of IPF. Some Traditional Chinese medicines may have more superiorities in delaying the progression of pulmonary fibrosis for their multi-target activities of this network regulation.

The resident pathobiont Staphylococcus xylosus in Nfkbiz-deficient skin accelerates spontaneous skin inflammation

IκBζ, which is encoded by the Nfkbiz gene, is a member of the nuclear IκB family of proteins that act as transcriptional regulators via association with NF-κB. Nfkbiz-deficient (Nfkbiz ^-/-) mice develop spontaneous dermatitis; however, the underlying mechanism has yet to be elucidated. In our study, we found higher skin pathology scores and more serum IgE antibodies and trans-epidermal water loss in Nfkbiz ^-/- than in Nfkbiz-sufficient (Nfkbiz ^+/-) mice. There was also greater expansion of IFN-γ-, IL-17A-, and IL-22-secreting CD4⁺ T cells and of IL-17A-secreting γδ⁺ T cells in the skin of Nfkbiz ^-/- mice than in with Nfkbiz ^+/- mice. Pyrosequencing analysis showed decreased diversity of resident bacteria and markedly expanded Staphylococcus (S.) xylosus in the skin of Nfkbiz ^-/- mice. Oral administration of antibiotics including cephalexin and enrofloxacin ameliorated skin inflammation. Topical application of S. xylosus also resulted in the expansion of IL-17A-secreting CD4⁺ T cells along with high levels of pro-inflammatory cytokines and chemokines in the skin of Nfkbiz ^-/- mice. The expansion of commensal S. xylosus may be one cause of skin dysbiosis in Nfkbiz ^-/- mice and suggests that the Nfkbiz gene may play a regulatory role in the microbiota-skin immunity axis.

Administration of JTE013 abrogates experimental asthma by regulating proinflammatory cytokine production from bronchial epithelial cells

Background

Sphingosine-1-phosphate (S1P) is a bioactive phospholipid that acts as a signal transducer by binding to S1P receptors (S1PR) 1 to 5. The S1P/S1PRs pathway has been associated with remodeling and allergic inflammation in asthma, but the expression pattern of S1PR and its effects on non-immune cells have not been completely clarified. The aim of this study was to examine the contribution of the signaling of S1P and S1PRs expressed in airway epithelial cells (ECs) to asthma responses in mice.

Methods

Bronchial asthma was experimentally induced in BALB/c mice by ovalbumin (OVA) sensitization followed by an OVA inhalation challenge. The effects of S1PR antagonists on the development of asthma were analyzed 24 h after the OVA challenge.

Results

Immunohistological analysis revealed S1PR1-3 expression on mouse airway ECs. Quantitative real-time polymerase chain reaction demonstrated that S1P greatly stimulated the induction of CCL3 and TIMP2 mRNA in human airway ECs, i.e., BEAS-2B cells, in a dose-dependent manner. Pretreatment with the S1PR2 antagonist JTE013 inhibited the CCL3 gene expression in BEAS-2B cells. Immunohistological analysis also showed that the expression level of CCL3 was attenuated by JTE013 in asthmatic mice. Furthermore, JTE013 as well as anti-CCL3 antibody attenuated allergic responses. Intratracheal administration of JTE013 also attenuated eosinophilic reactions in bronchoalveolar lavage fluids. S1P induced transcription factor NFκB activation, while JTE013 greatly reduced the NFκB activation.

Conclusions

JTE013 attenuated allergic airway reactions by regulating CCL3 production from bronchial ECs. The intratracheal administration of JTE013 may be a promising therapeutic strategy for bronchial asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0465-x) contains supplementary material, which is available to authorized users.

Infiltrating T cells promote renal cell carcinoma (RCC) progression via altering the estrogen receptor β-DAB2IP signals

Previous studies indicated the T cells, one of the most common types of immune cells existing in the microenvironment of renal cell carcinoma (RCC), may influence the progression of RCC. The potential linkage of T cells and the estrogen receptor beta (ERβ), a key player to impact RCC progression, however, remains unclear. Our results demonstrate that RCC cells can recruit more T cells than non-malignant kidney cells. Using an in vitro matrigel invasion system, we found infiltrating T cells could promote RCC cells invasion via increasing ERβ expression and transcriptional activity. Mechanism dissection suggested that co-culturing T cells with RCC cells released more T cell attraction factors, including IFN-γ, CCL3 and CCL5, suggesting a positive regulatory feed-back mechanism. Meanwhile, infiltrating T cells may also promote RCC cell invasion via increased ERβ and decreased DAB2IP expressions, and knocking down DAB2IP can then reverse the T cells-promoted RCC cell invasion. Together, our results suggest that infiltrating T cells may promote RCC cell invasion via increasing the RCC cell ERβ expression to inhibit the tumor suppressor DAB2IP signals. Further mechanism dissection showed that co-culturing T cells with RCC cells could produce more IGF-1 and FGF-7, which may enhance the ERβ transcriptional activity. The newly identified relationship between infiltrating T cells/ERβ/DAB2IP signals may provide a novel therapeutic target in the development of agents against RCC.

Cytokine profiles in nasal fluid of patients with seasonal or persistent allergic rhinitis

Background

New therapeutic approaches with biologic agents such as anti-cytokine antibodies are currently on trial for the treatment of asthma, rhinosinusitis or allergic diseases necessitating patient selection by biomarkers. Allergic rhinitis (AR), affecting about 20 % of the Canadian population, is an inflammatory disease characterised by a disequilibrium of T-lymphocytes and tissue eosinophilia. Aim of the present study was to describe distinct cytokine patterns in nasal secretion between seasonal and perennial AR (SAR/PAR), and healthy controls by comparing cytokines regulating T-cells or stimulating inflammatory cells, and chemokines.

Methods

Nasal secretions of 44 participants suffering from SAR, 45 participants with PAR and 48 healthy controls were gained using the cotton wool method, and analysed for IL-1β, IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17, GM-CSF, G-CSF, IFN-γ, MCP-1, MIP-1α, MIP-1β, eotaxin, and RANTES by Bio-Plex Cytokine Assay as well as for ECP and tryptase by UniCAP-FEIA.

Results

Participants with SAR or PAR presented elevated levels of tryptase, ECP, MCP-1, and MIP-1β, while values of GM-CSF, G-CSF, IL-1β, and IL-6 did not differ from the controls. Increased levels of IL-5, eotaxin, MIP-1α, and IL-17 and decreased levels of IFN-γ, IL-12 and IL-10 were found in SAR only. RANTES was elevated in SAR in comparison to PAR. Interestingly, we found reduced levels of IL-4 in PAR and of IL-13 in SAR.

Conclusions

Elevated levels of proinflammatory cytokines were seen in both disease entities. They were, however, more pronounced in SAR, indicating a higher degree of inflammation. This study suggests a downregulation of T_H1 and T_reg-lymphocytes and an upregulation of T_H17 in SAR. Moreover, the results display a prominent role of eosinophils and mast cells in AR. The observed distinct cytokine profiles in nasal secretion may prove useful as a diagnostic tool helping to match patients to antibody therapies.

Etanercept blocks inflammatory responses orchestrated by TNF-α to promote transplanted cell engraftment and proliferation in rat liver

Engraftment of transplanted cells is critical for liver-directed cell therapy, but most transplanted cells are rapidly cleared from liver sinusoids by proinflammatory cytokines/chemokines/receptors after activation of neutrophils or Kupffer cells (KCs). To define whether tumor necrosis factor alpha (TNF-α) served roles in cell-transplantation-induced hepatic inflammation, we used the TNF-α antagonist, etanercept (ETN), for studies in syngeneic rat hepatocyte transplantation systems. After cell transplantation, multiple cytokines/chemokines/receptors were overexpressed, whereas ETN before cell transplantation essentially normalized these responses. Moreover, ETN down-regulated cell-transplantation-induced intrahepatic release of secretory cytokines, such as high-mobility group box 1. These effects of ETN decreased cell-transplantation-induced activation of neutrophils, but not of KCs. Transplanted cell engraftment improved by several-fold in ETN-treated animals. These gains in cell engraftment were repeatedly realized after pretreatment of animals with ETN before multiple cell transplantation sessions. Transplanted cell numbers did not change over time, indicating absence of cell proliferation after ETN alone. By contrast, in animals preconditioned with retrorsine and partial hepatectomy, cell transplantation after ETN pretreatment significantly accelerated liver repopulation, compared to control rats.

CONCLUSION

TNF-α plays a major role in orchestrating cell-transplantation-induced inflammation through regulation of multiple cytokines/chemokines/receptor expression. Because TNF-α antagonism by ETN decreased transplanted cell clearance, improved cell engraftment, and accelerated liver repopulation, this pharmacological approach to control hepatic inflammation will help optimize clinical strategies for liver cell therapy.

IL-5 triggers a cooperative cytokine network that promotes eosinophil precursor maturation

Eosinophils originate in the bone marrow from an eosinophil lineage-committed, IL-5Rα-positive, hematopoietic progenitor (eosinophil progenitor). Indeed, IL-5 is recognized as a critical regulator of eosinophilia and has effects on eosinophil progenitors, eosinophil precursors, and mature eosinophils. However, substantial levels of eosinophils remain after IL-5 neutralization or genetic deletion, suggesting that there are alternative pathways for promoting eosinophilia. In this study, we investigated the contributory role of IL-5 accessory cytokines on the final stages of eosinophil differentiation. IL-5 stimulation of low-density bone marrow cells resulted in expression of a panel of cytokines and cytokine receptors, including several ligand-receptor pairs. Notably, IL-4 and IL-4Rα were expressed by eosinophil precursors and mature eosinophils. Signaling through IL-4Rα promoted eosinophil maturation when IL-5 was present, but IL-4 stimulation in the absence of IL-5 resulted in impaired eosinophil survival, suggesting that IL-4 cooperates with IL-5 to promote eosinophil differentiation. In contrast, CCL3, an eosinophil precursor-produced chemokine that signals through CCR1, promotes terminal differentiation of CCR1-positive eosinophil precursors in the absence of IL-5, highlighting an autocrine loop capable of sustaining eosinophil differentiation. These findings suggest that brief exposure to IL-5 is sufficient to initiate a cytokine cooperative network that promotes eosinophil differentiation of low-density bone marrow cells independent of further IL-5 stimulation.

The deleterious role of basophils in systemic lupus erythematosus

Systemic lupus erythematosus is a complex autoimmune disease of multifactorial origins. All compartments of the immune system appear to be affected, at least in some way, and to contribute to disease pathogenesis. Because of an escape from negative selection autoreactive T and B cells accumulate in SLE patients leading to the production of autoantibodies mainly raised against nuclear components and their subsequent deposition into target organs. We recently showed that basophils, in an IgE and IL-4 dependent manner, contribute to SLE pathogenesis by amplifying autoantibody production. Here, we summarize what we have learned about the deleterious role of basophils in lupus both in a mouse model and in SLE patients. We discuss which possible pathways could be involved in basophil activation and recruitment to secondary lymphoid organs during SLE, and how basophils may amplify autoantibody production.

Acteoside inhibits type Ι allergy through the down-regulation of Ca/NFAT and JNK MAPK signaling pathways in basophilic cells

We have previously reported that acteoside inhibits the release of β-hexosaminidase from immunoglobulin E (IgE)-sensitized and bovine serum albumin-stimulated rat basophilic leukemia cells as well as the intracellular calcium level, release of histamine from, and production of tumor necrosis factor-alpha and interleukin-4 in human basophilic (KU812) cells. However, the molecular mechanism underlying the anti-allergic effects of acteoside has not yet been elucidated. Here, we used microarray analysis to determine the global gene expression profile of KU812 cells treated with acteoside and calcium ionophore A23187 plus phorbol-12-myristate 13-acetate (A23187+PMA), and the results were validated by real-time polymerase chain reaction (PCR) and Western blotting. Microarray analysis results showed that of the 201 genes in the microarray, 149 genes were up-regulated, while 52 genes were down-regulated. The significantly down-regulated genes have functions as chemokine and IgE receptors, as well as for immune response. Results of the validation of the microarray results using real-time PCR showed a significant decrease in the expressions of Fc fragment of IgE, high affinity I, receptor for; alpha polypeptide (FCER1A) and nuclear factor of activated T cell, cytoplasmic, calcineurin-dependent 1 (NFATC1) genes. Furthermore, Western blotting showed a decrease in the phosphorylation of mitogen-activated protein kinase (MAPK) Jun N terminal kinase (JNK), revealing the role of JNK MAPK in acteoside-mediated allergy inhibition. We determined that the anti-allergy effects of acteoside were due to the down-regulation of the expressions of the chemokine ligand 1 (CCL1), CCL2, CCL3, CCL4, FCER1A and NFATC1 genes and the inhibition of the MAPK pathway through decreased JNK phosphorylation.

New twists to an old story: novel concepts in the pathogenesis of allergic eye disease

The prevalence of allergy is rising globally at a very significant rate, which is currently at 20-40% of individuals in westernized nations. In the eye, allergic conditions can take on the acute form such as in seasonal and perennial allergic conjunctivitis, or a more severe and debilitating chronic form such as in vernal and atopic keratoconjunctivitis. Indeed, some key aspects of allergic eye disease pathophysiology are understood, such as the role of mast cells in the acute allergic reaction, and the contribution of eosinophils in late-onset and chronic allergy. However, recent developments in animal models and clinical studies have uncovered new and important roles for previously underappreciated players, including chemokine receptors on ocular surface dendritic cells such as CCR7, the contribution of conjunctival epithelium to immunity, histamine and leukotriene receptors on conjunctival goblet cells and a role for mast cells in late-onset manifestations. Furthermore, recent work in animal models has delineated the contribution of IL-4 in the increased incidence of corneal graft rejection in hosts with allergic conjunctivitis. Recent studies such as these mean that conventional paradigms and concepts should be revisited. The aim of this review is to highlight some of the most recent advances and insights on newly appreciated players in the pathogenesis of allergic eye disease.

Interferon-gamma inhibits healing post scald burn injury

Impaired healing after severe burns remains a reason for prolonged hospitalization, opportunistic infections, and debilitating scarring. Interferon-gamma (IFN-γ) is an important immune regulator that has been shown to inhibit collagen synthesis by fibroblasts, resulting in delayed healing in incision wounds. To determine whether IFN-γ plays similar roles in the healing process after severe burn, we induced scald injury in mice deficient or sufficient in IFN-γ and examined local responses. In the absence of IFN-γ, scalded areas healed faster. This was associated with attenuated local inflammatory responses, enhanced reepithelialization, increased proliferation of keratinocytes in reepithelialized leading edges, and up-regulation of growth factors in burned skin areas. Furthermore, angiogenesis and myofibroblast formation commenced and terminated earlier in IFN-γ(-/-) mice compared with wild type (WT) controls. Our observations demonstrate that inhibition of IFN-γ results in accelerated healing after burn injury by dampening excessive inflammation and facilitating reepithelialization, collagen deposition, and wound contraction.

Evidence that formation of vimentin mitogen-activated protein kinase (MAPK) complex mediates mast cell activation following FcεRI/CC chemokine receptor 1 cross-talk

Accumulating evidence points to cross-talk between FcεRI and CC chemokine receptor (CCR)-mediated signaling pathways in mast cells. Here, we propose that vimentin, a protein comprising type III intermediate filament, participates in such cross-talk for CCL2/monocyte chemotactic protein 1 (MCP-1) production in mast cells, which is a mechanism for allergic inflammation. Co-stimulation via FcεRI, using IgE/antigen, and CCR1, using recombinant CCL3/macrophage inflammatory protein-1α (MIP-1α), increased expression of phosphorylated, disassembled, and soluble vimentin in rat basophilic leukemia (RBL)-2H3 cells expressing human CCR1 (RBL-CCR1 cells) and bone marrow-derived murine mast cells, both models of mucosal type mast cells. Furthermore, co-stimulation enhanced production of CCL2 as well as phosphorylation of MAPK. Treating the cells with p38 MAPK inhibitor SB203580, but not with MEK inhibitor PD98058, reduced CCL2 production, suggesting that p38 MAPK, but not ERK1/2, plays a critical role in the chemokine production. Immunoprecipitation analysis showed that vimentin interacts with phosphorylated ERK1/2 and p38 MAPKs in the co-simulated cells. Preventing disassembly of the vimentin by aggregating vimentin filaments using β,β'-iminodipropionitrile reduced the interaction of vimentin with phosphorylated MAPKs as well as CCL2 production in the cells. Taken together, disassembled vimentin interacting with phosphorylated p38 MAPK could mediate CCL2 production in mast cells upon FcεRI and CCR1 activation.

Oral microbial biofilm stimulation of epithelial cell responses

Oral bacterial biofilms trigger chronic inflammatory responses in the host that can result in the tissue destructive events of periodontitis. However, the characteristics of the capacity of specific host cell types to respond to these biofilms remain ill-defined. This report describes the use of a novel model of bacterial biofilms to stimulate oral epithelial cells and profile select cytokines and chemokines that contribute to the local inflammatory environment in the periodontium. Monoinfection biofilms were developed with Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis on rigid gas-permeable contact lenses. Biofilms, as well as planktonic cultures of these same bacterial species, were incubated under anaerobic conditions with a human oral epithelial cell line, OKF4, for up to 24h. Gro-1α, IL1α, IL-6, IL-8, TGFα, Fractalkine, MIP-1α, and IP-10 were shown to be produced in response to a range of the planktonic or biofilm forms of these species. P. gingivalis biofilms significantly inhibited the production of all of these cytokines and chemokines, except MIP-1α. Generally, the biofilms of all species inhibited Gro-1α, TGFα, and Fractalkine production, while F. nucleatum biofilms stimulated significant increases in IL-1α, IL-6, IL-8, and IP-10. A. naeslundii biofilms induced elevated levels of IL-6, IL-8 and IP-10. The oral streptococcal species in biofilms or planktonic forms were poor stimulants for any of these mediators from the epithelial cells. The results of these studies demonstrate that oral bacteria in biofilms elicit a substantially different profile of responses compared to planktonic bacteria of the same species. Moreover, certain oral species are highly stimulatory when in biofilms and interact with host cell receptors to trigger pathways of responses that appear quite divergent from individual bacteria.

Basophil recruitment and activation in inflammatory skin diseases

BACKGROUND

Basophils are blood leukocytes constituting less than 1% of leukocytes. They share morphological and functional similarities with mast cells, but recent studies indicate that basophils play non-redundant roles via the release of several cytokines and lipid mediators, as well as functioning as antigen presenting cells. However, basophil infiltration into the tissues in human skin diseases remains to be addressed.

METHODS

The infiltration of basophils in 24 skin diseases (136 samples) was immunohistochemically analyzed using basophil-specific BB1 antibody. In addition, activation of blood basophils was examined by assessing CD203c expression with flow cytometry.

RESULTS

Basophils were detected in skin lesions of atopic dermatitis, prurigo, urticaria, bullous pemphigoid, drug eruptions, eosinophilic pustular folliculitis, insect bites, scabies, Henoch-Schönlein purpura and dermatomyositis. While cell densities in urticaria, bullous pemphigoid and eosinophilic pustular folliculitis were prominent, much lower numbers of basophils were seen in lesional skin of atopic dermatitis. Basophils were entirely absent in psoriasis vulgaris, mastocytosis, tumoral lesions, systemic sclerosis, and systemic lupus erythematosus. Levels of CD203c expression on blood basophils from prurigo and urticaria patients were higher than those from healthy donors.

CONCLUSIONS

Basophils infiltrate into skin lesions more commonly than previously thought, and thus they may play important roles in a variety of inflammatory skin diseases.

Catestatin, a neuroendocrine antimicrobial peptide, induces human mast cell migration, degranulation and production of cytokines and chemokines

Catestatin, a neuroendocrine peptide with effects on human autonomic function, has recently been found to be a cutaneous antimicrobial peptide. Human catestatin exhibits three single nucleotide polymorphisms: Gly364Ser, Pro370Leu and Arg374Gln. Given reports indicating that antimicrobial peptides and neuropeptides induce mast cell activation, we postulated that catestatin might stimulate numerous functions of human mast cells, thereby participating in the regulation of skin inflammatory responses. Catestatin and its naturally occurring variants caused the human mast cell line LAD2 and peripheral blood-derived mast cells to migrate, degranulate and release leukotriene C(4) and prostaglandins D(2) and E(2). Moreover, catestatins increased intracellular Ca(2+) mobilization in mast cells, and induced the production of pro-inflammatory cytokines/chemokines such as granulocyte-macrophage colony-stimulating factor, monocyte chemotactic protein-1/CCL2, macrophage inflammatory protein-1α/CCL3 and macrophage inflammatory protein-1β/CCL4. Our evaluation of possible cellular mechanisms suggested that G-proteins, phospholipase C and the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) are involved in catestatin-induced mast cell activation as evidenced by the inhibitory effects of pertussis toxin (G-protein inhibitor), U-73122 (phospholipase C inhibitor) and U0126 (ERK inhibitor), respectively. We also found that human mast cells express the α7 subunit of the nicotinic acetylcholine receptor at both the mRNA and protein levels. Given that silencing the α7 receptor mRNA and an α7-specific inhibitor did not affect catestatin-mediated activation of mast cells, however, we concluded that this receptor is not likely to be functional in human mast cell stimulation by catestatins. Our finding that the neuroendocrine antimicrobial peptide catestatin activates human mast cells suggests that this peptide might have immunomodulatory functions, and provides a new link between neuroendocrine and cutaneous immune systems.

A pathway-based approach to find novel markers of local glucocorticoid treatment in intermittent allergic rhinitis

BACKGROUND

Glucocorticoids (GCs) may affect the expression of hundreds of genes in different cells and tissues from patients with intermittent allergic rhinitis (IAR). It is a formidable challenge to understand these complex changes by studying individual genes. In this study, we aimed to identify (i) pathways affected by local GC treatment and (ii) examine if those pathways could be used to find novel markers of local GC treatment in nasal fluids from patients with IAR.

METHODS

Gene expression microarray- and iTRAQ-based proteomic analyses of nasal fluids, nasal fluid cells and nasal mucosa from patients with IAR were performed to find pathways enriched for differentially expressed genes and proteins. Proteins representing those pathways were analyzed with ELISA in an independent material of nasal fluids from 23 patients with IAR before and after treatment with a local GC.

RESULTS

Transcriptomal and proteomic high-throughput analyses of nasal fluids, nasal fluid cells and nasal mucosal showed that local GC treatment affected a wide variety of pathways in IAR such as the glucocorticoid receptor pathway and the acute phase response pathway. Extracellular proteins encoded by genes in those pathways were analyzed in an independent material of nasal fluids from patients. Proteins that changed significantly in expression included known biomarkers such as eosinophil cationic protein but also proteins that had not been previously described in IAR, namely CCL2, M-CSF, CXCL6 and apoH.

CONCLUSION

Pathway-based analyses of genomic and proteomic high-throughput data can be used as a complementary approach to identify novel potential markers of GC treatment in IAR.

The hydroxyflavone, fisetin, suppresses mast cell activation induced by interaction with activated T cell membranes

BACKGROUND AND PURPOSE

Cell-to-cell interactions between mast cells and activated T cells are increasingly recognized as a possible mechanism in the aetiology of allergic or non-allergic inflammatory disorders. To determine the anti-allergic effect of fisetin, we examined the ability of fisetin to suppress activation of the human mast cell line, HMC-1, induced by activated Jurkat T cell membranes.

EXPERIMENTAL APPROACH

HMC-1 cells were incubated with or without fisetin for 15 min and then co-cultured with Jurkat T cell membranes activated by phorbol-12-myristate 13-acetate for 16 h. We determined gene expression in activated HMC-1 cells by DNA microarray and quantitative reverse transcription (RT)-PCR analysis. We also examined activation of the transcription factor NF-kappaB and MAP kinases (MAPKs) in activated HMC-1 cells.

KEY RESULTS

Fisetin suppresses cell spreading and gene expression in HMC-1 cells stimulated by activated T cell membranes. Additionally, we show that these stimulated HMC-1 cells expressed granzyme B. The stimulatory interaction also induced activation of NF-kappaB and MAPKs; these activations were suppressed by fisetin. Fisetin also reduced the amount of cell surface antigen CD40 and intercellular adhesion molecule-1 (ICAM-1) on activated HMC-1 cells.

CONCLUSIONS AND IMPLICATIONS

Fisetin suppressed activation of HMC-1 cells by activated T cell membranes by interfering with cell-to-cell interaction and inhibiting the activity of NF-kappaB and MAPKs and thereby suppressing gene expression. Fisetin may protect against the progression of inflammatory diseases by limiting interactions between mast cells and activated T cells.

Identification of glucocorticoid-induced TNF receptor-related protein ligand on keratinocytes: ligation by GITR induces keratinocyte chemokine production and augments T-cell proliferation

Glucocorticoid-induced tumor necrosis factor (TNF) receptor-related protein ligand (GITRL) is a recently described co-stimulatory molecule expressed by antigen-presenting cells (APCs). Activated keratinocytes are known to engage intraepithelial T cells through co-stimulatory molecules. This study investigated the expression and function of GITRL in resting keratinocytes. We showed by immunofluorescence and flow cytometry that keratinocytes from Balb/C and C57Bl/6 mice, as well as PAM 212 murine cell line keratinocytes and human epidermal keratinocytes (HEK), express cell-surface GITRL. Stimulation of murine skin biopsies and HEK with GITR fusion protein (GITR: Fc FP) resulted in mRNA induction for chemoattractants: cutaneous T-cell-attracting chemokine (CTACK), thymus and activation-regulated chemokine (TARC), IL-8, monocyte chemoattractant protein-1 (MCP-1), and murine beta-defensin 3 (MBD3). Immunofluorescent studies on mouse biopsies treated with GITR: Fc FP confirmed corresponding TARC and MCP-1 protein production by keratinocytes. Chemokine induction was shown to be NF-kappaB-mediated. T-cell proliferation was enhanced by the addition of keratinocytes. This was reversed by pretreatment with an anti-GITRL antibody. We conclude that keratinocytes express GITRL, and that through this important co-stimulatory molecule, they have the potential to influence T-cell numbers in the skin through chemokine production and through a direct cell-cell effect on T-cell proliferation.

Hepatocyte transplantation-induced liver inflammation is driven by cytokines-chemokines associated with neutrophils and Kupffer cells

BACKGROUND & AIMS

Hepatocyte transplantation-induced liver inflammation impairs cell engraftment. We defined whether proinflammatory cytokines and chemokines played roles in regulation of hepatocyte engraftment in the liver.

METHODS

We performed studies over up to 3 weeks in rat hepatocyte transplantation systems. Expression of 84 cytokine-chemokine genes was studied by quantitative real-time polymerase chain reactions. Expression of selected up-regulated genes was verified by immunohistochemistry. Hepatic recruitment of neutrophils was demonstrated by myeloperoxidase activity assays, and Kupffer cell activation was established by carbon phagocytosis assays. The role of neutrophils and Kupffer cells in regulating expression of cytokine-chemokine genes as well as cell engraftment was determined by cell depletion studies.

RESULTS

Within 6 hours after syngeneic cell transplantation, expression of 25 cytokine-chemokine genes increased by 2- to 123-fold, P < .05. These genes were largely associated with activated neutrophils and macrophages, including chemokine ligands, CXCL1, CXCL2, CCL3, CCL4; chemokine receptors, CXCR1 or CXCR2, CCR1, CCR2; and regulatory cytokines tumor necrosis factor alpha and interleukin-6. Inflammatory cells in the liver immunostained for CCR1, CCR2, CXCR1, and CXCR2, which indicated that up-regulated messenger RNA was appropriately translated. When neutrophils and Kupffer cells were depleted with neutrophil antiserum and gadolinium chloride, respectively, before transplanting cells, cell transplantation-induced cytokine-chemokine responses were attenuated. Virtually all abnormalities subsided in animals treated with neutrophil antiserum plus gadolinium chloride. Moreover, depletion of neutrophils or Kupffer cells improved engraftment of transplanted cells.

CONCLUSIONS

Cell transplantation-induced liver inflammation involves proinflammatory cytokine-chemokine systems capable of modulation by neutrophils and Kupffer cells. This offers new directions for optimizing cell therapy strategies.

Impact of anti-inflammatory agents on the gene expression profile of stimulated human neutrophils: unraveling endogenous resolution pathways

Adenosine, prostaglandin E(2), or increased intracellular cyclic AMP concentration each elicit potent anti-inflammatory events in human neutrophils by inhibiting functions such as phagocytosis, superoxide production, adhesion and cytokine release. However, the endogenous molecular pathways mediating these actions are poorly understood. In the present study, we examined their impact on the gene expression profile of stimulated neutrophils. Purified blood neutrophils from healthy donors were stimulated with a cocktail of inflammatory agonists in the presence of at least one of the following anti-inflammatory agents: adenosine A(2A) receptor agonist CGS 21680, prostaglandin E(2), cyclic-AMP-elevating compounds forskolin and RO 20-1724. Total RNA was analyzed using gene chips and real-time PCR. Genes encoding transcription factors, enzymes and regulatory proteins, as well as secreted cytokines/chemokines showed differential expression. We identified 15 genes for which the anti-inflammatory agents altered mRNA levels. The agents affected the expression profile in remarkably similar fashion, suggesting a central mechanism limiting cell activation. We have identified a set of genes that may be part of important resolution pathways that interfere with cell activation. Identification of these pathways will improve understanding of the capacity of tissues to terminate inflammatory responses and contribute to the development of therapeutic strategies based on endogenous resolution.