Identification of granulocyte subtype–selective receptors and ion channels by using a high-density oligonucleotide probe array

Sodium Butyrate Modulates Mucosal Inflammation Injury Mediated by GPR41/43 in the Cecum of Goats Fed a High Concentration Diet

Emerging data indicate that excessive short chain fatty acids can mediate the downstream mitogen-activated protein kinase pathways by activating G-protein coupled receptor 41/43 (GPR41/43) to initiate the inflammatory response. The current study was conducted to investigate if a high concentrate (HC) supplemented with sodium butyrate can alleviate the inflammation and if an epigenetic mechanism is involved in regulating the expression of the key GPR41/43 genes in the cecum. Twelve lactating goats were randomly divided into two groups: the control group fed the HC diet and the treatment group fed the HC diet supplemented with sodium butyrate (HCB). Our results suggested that the supplementation of sodium butyrate significantly increased the pH value in the rumen and cecum, downregulated the expression of GPR41/43 and related inflammatory cytokines, upregulated the expression of tight junction proteins, and reduced the protein expression levels of GPR 41/43, ERK1/2, and p38. Moreover, the ratios of DNA methylation and chromatin compaction in the promoter region of the GPR41/43 genes were altered due to the addition of sodium butyrate. In brief, dietary addition of sodium butyrate can reduce the inflammatory injury to the cecal mucosa in lactating goats and can affect the expression of GPR41/43 via epigenetic modification.

Detection of Mast Cells Expressing c-Kit Using Antibody Covalently Bound to Gelatin Elongated from Surface of Immunosensor Based on Surface Plasmon Resonance

An immunosensor based on surface plasmon resonance was applied to detect mast cells expressing c-Kit. Sufficient detection of the mast cells was achieved by covalent immobilization of gelatin firstly on the sensor surface and followed by covalent binding of the anti-c-Kit antibody to lysine residues in the gelatin molecules through bis(sulfosuccinimidyl)suberate (BS3) treatment. By using BS3, which is a homo-bifunctional reagent, the lysine residues of the anti-c-Kit antibody easily bound to the lysine residues of the gelatin in the physiological condition. The lower limit of detection was 10⁴ cells/mL.

Human eosinophils constitutively express a unique serine protease, PRSS33

BACKGROUND

Eosinophils play important roles in asthma, especially airway remodeling, by producing various granule proteins, chemical mediators, cytokines, chemokines and proteases. However, protease production by eosinophils is not fully understood. In the present study, we investigated the production of eosinophil-specific proteases/proteinases by transcriptome analysis.

METHODS

Human eosinophils and other cells were purified from peripheral blood by density gradient sedimentation and negative/positive selections using immunomagnetic beads. Protease/proteinase expression in eosinophils and release into the supernatant were evaluated by microarray analysis, qPCR, ELISA, flow cytometry and immunofluorescence staining before and after stimulation with eosinophil-activating cytokines and secretagogues. mRNAs for extracellular matrix proteins in human normal fibroblasts were measured by qPCR after exposure to recombinant protease serine 33 (PRSS33) protein (rPRSS33), created with a baculovirus system.

RESULTS

Human eosinophils expressed relatively high levels of mRNA for metalloproteinase 25 (MMP25), a disintegrin and metalloprotease 8 (ADAM8), ADAM10, ADAM19 and PRSS33. Expression of PRSS33 was the highest and eosinophil-specific. PRSS33 mRNA expression was not affected by eosinophil-activating cytokines. Immunofluorescence staining showed that PRSS33 was co-localized with an eosinophil granule protein. PRSS33 was not detected in the culture supernatant of eosinophils even after stimulation with secretagogues, but its cell surface expression was increased. rPRSS33 stimulation of human fibroblasts increased expression of collagen and fibronectin mRNAs, at least in part via protease-activated receptor-2 activation.

CONCLUSIONS

Activated eosinophils may induce fibroblast extracellular matrix protein synthesis via cell surface expression of PRSS33, which would at least partly explain eosinophils' role(s) in airway remodeling.

Perspectives on the therapeutic potential of short-chain fatty acid receptors

There is rapidly growing interest in the human microbiome because of its implication in metabolic disorders and inflammatory diseases. Consequently, understanding the biology of short chain fatty acids and their receptors has become very important for identifying novel therapeutic avenues. GPR41 and GPR43 have been recognized as the cognate receptors for SCFAs and their roles in metabolism and inflammation have drawn much attention in recent years. GPR43 is highly expressed on immune cells and has been suggested to play a role in inflammatory diseases such as inflammatory bowel disease. Both GPR41 and GPR43 have been implicated in diabetes and obesity via the regulation of adipose tissue and gastrointestinal hormones. So far, many studies have provided contradictory results, and therefore further research is required to validate these receptors as drug targets. We will also discuss the synthetic modulators of GPR41 and GPR43 that are critical to understanding the functions of these receptors. [BMB Reports 2014; 47(3): 173-178]

Cystatin SN upregulation in patients with seasonal allergic rhinitis

Seasonal allergic rhinitis (SAR) to the Japanese cedar, Cryptomeria japonica (JC) pollen is an IgE-mediated type I allergy affecting nasal mucosa. However, the molecular events underlying its development remain unclear. We sought to identify SAR-associated altered gene expression in nasal epithelial cells during natural exposure to JC pollen. We recruited study participants in 2009 and 2010 and collected nasal epithelial cells between February and April, which is the period of natural pollen dispersion. Fifteen patients with SAR-JC and 13 control subjects were enrolled in 2009, and 17 SAR-JC patients, 13 sensitized asymptomatic subjects (Sensitized), and 15 control subjects were enrolled in 2010. Total RNA was extracted from nasal epithelial cells and 8 SAR-JC patients and 6 control subjects in 2009 were subjected to microarray analysis with the Illumina HumanRef-8 Expression BeadChip platform. Allergen-stimulated histamine release was examined in the peripheral blood basophils isolated from patients with SAR. We identified 32 genes with significantly altered expression during allergen exposure. One of these, CST1 encodes the cysteine protease inhibitor, cystatin SN. CST1 expression in nasal epithelial cells was significantly upregulated in both the 2009 and 2010 SAR-JC groups compared with the control groups. Immunohistochemical staining confirmed the increased expression of CST1 in the nasal epithelial cells of SAR patients. Addition of exogenous CST1 to basophils inhibited JC allergen-stimulated histamine release in vitro. We propose that CST1 may contribute to inactivation of protease allergens and help re-establish homeostasis of the nasal membranes.

Histamine production by human neutrophils

Histamine is an important mediator in the development of allergic reactions. Only a small subset of human cell types is able to produce histamine. No previous studies have shown that human neutrophils are among them. The present work was undertaken to analyze whether human neutrophils produce histamine, and to determine what agonists are involved in histamine production by human neutrophils. The expression of histidine decarboxylase in human neutrophils was established by quantitative PCR, Western blotting, and flow cytometry analysis. The activity of the enzyme was determined by ELISA, which measured histamine in the culture supernatant of neutrophils stimulated with a set of classical agonists. Human neutrophils are bona fide histamine-producing cells. Neutrophils store ∼0.29 pg/cell and release ∼50% of the histamine content in an antigen-dependent manner and on stimulation with other neutrophil agonists. Basal expression of histidine decarboxylase, the rate-limiting enzyme in histamine production, is higher in neutrophils from patients with allergies than from healthy donors. Our results cannot be ascribed to cell contamination for several reasons. LPS failed to induce histamine release by basophils, whereas it induced histamine release by neutrophils; and we did not detect basophils, monocytes, or lymphocytes in our neutrophil preparations. Eosinophils, albeit detected, were only 0.001-0.004% of the final cell population, and they did not store or release histamine on antigen or LPS stimulation. Antigens to which patients with allergies were sensitized stimulated release of histamine from neutrophils. These observations represent a novel view of neutrophils as possible source of histamine in the allergic diseases.

RAGE regulation and signaling in inflammation and beyond

RAGE is a key molecule in the onset and sustainment of the inflammatory response. New studies indicate that RAGE might represent a new link between the innate and adaptive immune system. RAGE belongs to the superfamily of Ig cell-surface receptors and is expressed on all types of leukocytes promoting activation, migration, or maturation of the different cells. RAGE expression is prominent on the activated endothelium, where it mediates leukocyte adhesion and transmigration. Moreover, proinflammatory molecules released from the inflamed or injured vascular system induce migration and proliferation of SMCs. RAGE binds a large number of different ligands and is therefore considered as a PRR, recognizing a structural motif rather than a specific ligand. In this review, we summarize the current knowledge about the signaling pathways activated in the different cell types and discuss a potential activation mechanism of RAGE, as well as putative options for therapeutic intervention.

Mast cells and IgE: from history to today

Role of mast cells in allergy had remained undetermined until the discovery of IgE in 1966. Then, IgE purified from many Liters of plasma, which had been donated from a patient with fatal myeloma, was distributed to researchers all over the world, and thus accelerated exploring the mechanisms involved in allergic reactions, particularly about the role of mast cells and basophils in the IgE-mediated reactions. Identification of mast cells as a progeny of a bone marrow hematopoietic stem cell in 1977 led us to successful in vitro culture of human mast cells. Along with the development of molecular biological techniques, the structure of the high affinity IgE receptor (FcεRI) was determined in 1989. These findings and subsequent investigations brought deeper understanding of IgE-mediated allergic diseases in the past half century, especially where mast cells are involved. We have now even obtained the information about whole genome expression of FcεRI-dependently activated mast cells. In sharp contrast to our comprehension of allergic diseases where IgE and mast cells are involved, the mechanisms involved in non-IgE-mediated allergic diseases or non-IgE-mediated phase of IgE-mediated diseases are almost left unsolved and are waiting for devoted investigators to reveal it.

Characterization of the expression of HTm4 (MS4A3), a cell cycle regulator, in human peripheral blood cells and normal and malignant tissues

HTm4 (MS4A3) is a member of a family of four-transmembrane proteins designated MS4A. MS4A proteins fulfil diverse functions, acting as cell surface signalling molecules and intracellular adapter proteins. Early reports demonstrated that HTm4 is largely restricted to the haematopoietic lineage, and is involved in cell cycle control, via a regulatory interaction with the kinase-associated phosphatase, cyclin A and cyclin-dependent kinase 2 (CDK2). Here we describe the expression pattern of HTm4 in peripheral blood cells using gene expression microarray technology, and in normal foetal and adult human tissues, as well as adult human cancers, using tissue microarray technology. Using oligonucleotide microarrays to evaluate HTm4 mRNA, all peripheral blood cell types demonstrated very low levels of HTm4 expression; however, HTm4 expression was greatest in basophils compared to eosinophils, which showed lower levels of HTm4 expression. Very weak HTm4 expression is found in monocytes, granulocytes and B cells, but not in T cells, by lineage specific haematopoietic cell flow cytometry analysis. Interestingly, phytohaemagglutinin stimulation increases HTm4 protein expression in peripheral blood CD4-T-lymphocytes over nearly undetectable baseline levels. Western blotting and immunohistochemical studies show strong HTm4 expression in the developing haematopoietic cells of human foetal liver. Immunohistochemical studies on normal tissue microarrays confirmed HTm4 expression in a subset of leucocytes in nodal, splenic tissues and thymic tissue, and weak staining in small numbers of cell types in non-haematopoietic tissues. Human foetal brain specimens from 19 to 31 gestational weeks showed that the strongest-staining cells are ventricular zone cells and the earliest-born, earliest-differentiating ‘pioneer’ neurons in the cortical plate, Cajal-Retzius and, to a lesser extent, subplate-like neurons. Malignant tissue microarray analysis showed HTm4 expression in a wide variety of adenocarcinomas, including breast, prostate and ovarian. These findings warrant the further study of the role of HTm4 in the cell cycle of both haematopoietic and tumour cells.

Human eosinophils produce and release a novel chemokine, CCL23, in vitro

BACKGROUND

CCL23 (MPIF1/CK-BETA-8) is a novel CC chemokine that plays important roles in the inhibition of myeloid progenitor cell development, the selective recruitment of resting T lymphocytes and monocytes, and the potentiation of VEGF-induced proliferation and migration of human endothelial cells. Since eosinophils participate in the pathogenesis of airway remodeling, we examined CCL23 production and release by human eosinophils in vitro.

METHODS

Using Ficoll and antibody-coated immunomagnetic beads, eosinophils and other blood cells were purified from peripheral blood samples obtained from normal subjects and mildly allergic patients. Eosinophils were cultured in the presence of 10 ng/ml granulocyte-macrophage colony-stimulating factor (GM-CSF), 10 ng/ml IL-5, 100 ng/ml IFN-γ, 100 ng/ml IFN-α, or immobilized secretory IgA (sIgA). Total mRNA was extracted after 6 h of culture, and mRNA expression was measured using a microarray and RT-PCR. The CCL23 concentrations in the supernatants and cell lysates after 24 and 48 h of culture were measured by ELISA.

RESULTS

CCL23 mRNAs (both CK-β8-1 and CK-β8) were constitutively expressed in fresh eosinophils, and their expression levels were higher than in other types of blood cells. CCL23 mRNAs were significantly increased by stimulation with GM-CSF and IL-5 and slightly by IFN-α and immobilized sIgA. Fresh eosinophils contained trace amounts of CCL23 protein. CCL23 was significantly released into the supernatant when the eosinophils were stimulated with GM-CSF or IL-5 but not with IFN-γ or immobilized sIgA.

CONCLUSION

Our data suggest that eosinophils produce and release CCL23 and may be involved in some in vivo physiological and pathological conditions.

Gene expression patterns of Th2 inflammation and intercellular communication in asthmatic airways

Asthma is canonically thought of as a disorder of excessive Th2-driven inflammation in the airway, although recent studies have described heterogeneity with respect to asthma pathophysiology. We have previously described distinct phenotypes of asthma based on the presence or absence of a three-gene "Th2 signature" in bronchial epithelium, which differ in terms of eosinophilic inflammation, mucin composition, subepithelial fibrosis, and corticosteroid responsiveness. In the present analysis, we sought to describe Th2 inflammation in human asthmatic airways quantitatively with respect to known mediators of inflammation and intercellular communication. Using whole-genome microarray and quantitative real-time PCR analysis of endobronchial biopsies from 27 mild-to-moderate asthmatics and 13 healthy controls with associated clinical and demographic data, we found that asthmatic Th2 inflammation is expressed over a variable continuum, correlating significantly with local and systemic measures of allergy and eosinophilia. We evaluated a composite metric describing 79 coexpressed genes associated with Th2 inflammation against the biological space comprising cytokines, chemokines, and growth factors, identifying distinctive patterns of inflammatory mediators as well as Wnt, TGF-β, and platelet-derived growth factor family members. This integrated description of the factors regulating inflammation, cell migration, and tissue remodeling in asthmatic airways has important consequences for the pathophysiological and clinical impacts of emerging asthma therapeutics targeting Th2 inflammation.

Agonism and allosterism: the pharmacology of the free fatty acid receptors FFA2 and FFA3

The free fatty acid receptors FFA2 and FFA3 are recently de-orphanized G protein-coupled receptors that share a group of short-chain free fatty acids as endogenous ligands. The expression of FFA2 and FFA3 by immune cells, in parts of the gastro-intestinal tract and by white adipocytes has suggested their potential as therapeutic targets in conditions including inflammation and obesity. However, although FFA2 and FFA3 display distinct structure-activity relationships for stimulation by short-chain free fatty acids, the overlap between these endogenous agonists and the lack of synthetic small molecule ligands that display selectivity between these two receptors has, until recently, hindered efforts to resolve their individual functions. Recently, chloro-alpha-(1-methylethyl)-N-2-thiazolylbenzeneacetamide has been described as an FFA2 selective ago-allosteric ligand, not only being a direct agonist but also acting as a positive allosteric modulator of the function of short-chain free fatty acids at FFA2. Mutation of a pair of key arginine residues near the top of transmembrane domains V and VII of both FFA2 and FFA3 eliminates the function of short-chain free fatty acids but is without effect on the direct agonist action of chloro-alpha-(1-methylethyl)-N-2-thiazolylbenzeneacetamide at FFA2, confirming the distinct nature of the binding site of the ago-allosteric regulator from the orthosteric binding site for free fatty acids. An understanding of structure-activity relationships for ligands related to chloro-alpha-(1-methylethyl)-N-2-thiazolylbenzeneacetamide is likely to provide greater insight into the mode of action and site of binding of this ligand, but further FFA2 and FFA3 selective ligands, preferably with higher potency/affinity, will be required to fully explore the physiological function of these receptors.

Stress repression in restrained rats by (R)-(-)-linalool inhalation and gene expression profiling of their whole blood cells

As an attempt to quantitatively analyze the physiopsychological effects elicited by odorants, white blood cells and gene expression were profiled in the whole blood of the rats exposed to (R)-(-)-linalool during restraint stress for 2 h. In neutrophils and lymphocytes, significant changes caused by the restraint were repressed by their exposure to the odorant. This indicates that inhalation attenuates stress-induced changes. Significant changes on the stress-induced variations were induced by inhalation in 115 gene expression levels. Of those, 109 genes were down-regulated, whereas the remaining 6 were up-regulated. These findings show that (R)-(-)-linalool inhalation represses stress-induced effects on the profiles of both blood cells and gene expression. Furthermore, these results suggest the possibility that the odorant-induced effects can be quantitatively evaluated by analyzing the profiles of blood cells and gene expression.

Basophils: a nonredundant contributor to host immunity

The role of basophils, the rarest of blood granulocytes, in host immunity has been a mystery. Long considered the poor relative of mast cells, basophils have received much recent attention because of the availability of new reagents and models that reveal unique properties of these cells. Basophils are known to have distinct roles in allergic hypersensitivity reactions and in the immune response to intestinal helminthes. In this review, we highlight these advances and summarize our current understanding of the repertoire of functions attributed to these cells. Despite these recent insights, we are likely only beginning to gain a full understanding of how and where these cells lend effector functions to vertebrate immunity. Advances are likely to come only with the development of specific reagents that enable the finer study of basophil lineage and function. Although many fundamental aspects of basophil biology remain unanswered, the prospects remain bright for unmasking new contributions by these unusual cells.

International Union of Pharmacology. LXXI. Free fatty acid receptors FFA1, -2, and -3: pharmacology and pathophysiological functions

Identification of G protein-coupled receptors that are activated by free fatty acids has led to considerable interest in their pharmacology and function because of the wide range of normal physiology and disease states in which fatty acids have been implicated. Free fatty acid receptor (FFA) 1 is activated by medium- to long-chain fatty acids and is expressed in the insulin-producing beta-cells of the pancreas. Activation of FFA1 has been proposed to mediate fatty acid augmentation of glucose-stimulated insulin secretion although it is unclear whether the known long-term detrimental effects of beta-cell exposure to high levels of fatty acids are also mediated through this receptor. The related receptors FFA2 and FFA3 are both activated by short-chain fatty acids although they have key differences in the signaling pathways they activate and tissue expression pattern. The aim of this review is to provide a comprehensive overview of the current understanding of the pharmacology and physiological role of these fatty acid receptors.

Elevated granulocyte colony-stimulating factor levels predict treatment failure in patients with Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is an acute vasculitis in young children, frequently associated with coronary artery aneurysms. The intravenous infusion of high-dose IgG (IVIG) effectively reduces the systemic inflammation and the incidence of coronary artery lesions, although the precise underlying mechanisms are unknown.

OBJECTIVE

We performed expression profiling of whole blood cells to investigate the mechanisms underlying the effect of IVIG and to identify biomarkers associated with unresponsiveness to IVIG.

METHODS

We compared the transcript abundance among pre-IVIG and post-IVIG patients and febrile control patients. Then we analyzed the mRNA levels and the protein levels among the different cohort of patients with KD who were either responsive or nonresponsive to the initial IVIG.

RESULTS

A total of 298 transcripts were overrepresented or underrepresented in the pre-IVIG patients compared with post-IVIG patients and febrile controls, of which 15 transcripts were differentially expressed in nonresponsive patients with KD compared with responsive patients before IVIG. The protein levels of polycythemia rubra vera 1, which was one of the most variably expressed transcripts in pre-IVIG patients, and the serum granulocyte colony-stimulating factor levels were significantly higher in nonresponsive patients than in responsive patients before the initial IVIG administration.

CONCLUSION

These findings suggest that the variable gene expression profiles were correlated to the responses of patients with KD to IVIG administration. Polycythemia rubra vera 1 and granulocyte colony-stimulating factor levels may be good biomarkers for predicting response to IVIG in patients with KD.

Induction of apoptosis in human basophils by anti-Fas antibody treatment in vitro

BACKGROUND

Basophils are thought to play an important role in the pathogenesis of allergic inflammation; however, the factors associated with basophil death are not fully understood. Fas (CD95) is a member of the TNF receptor superfamily and is known to induce apoptosis in activated T cells, neutrophils and eosinophils. In the present study, the expression and function of Fas in human basophils were investigated in vitro.

METHODS

Human cultured basophils were obtained by culturing cord blood-derived CD34+ cells in the presence of 2.5 ng/ml of IL-3 for 5-6 weeks. The expression of Fas was measured using flow cytometry. Cell viability and morphological changes after the incubation of basophils with anti-Fas mAb (clone CH11, IgM) in the presence of 1 ng/ml of IL-3 were measured using the trypan blue dye exclusion test and light microscopy, respectively.

RESULTS

Human cultured basophils constitutively and significantly expressed Fas on their cell surfaces. Treatment with anti-Fas monoclonal antibody (mAb) significantly reduced basophil viability in a time- and dose-dependent manner. When basophils were incubated with 10 ng/ml of anti-Fas mAb or control for 72 h, the basophil viability was 27.3 +/- 8.8% and 89.3 +/- 5.2%, respectively (p < 0.01). Anti-Fas mAb-treated basophils were shrunken and exhibited condensed nuclei, consistent with apoptosis.

CONCLUSIONS

Our findings indicate that human basophils express functional Fas on their cell surfaces, and signaling via Fas may regulate basophil survival in vivo.

Progress in allergy signal research on mast cells: systemic approach to mast cell biology in allergic diseases

At the end of the last century, microarray technology that examines the total genes and transcripts present in a cell became available as a laboratory tool. Mast cells are known to play a pivotal role in initiating allergic inflammation by releasing various mediators and cytokines. According to the recent microarray-based studies, mast cells have been found to be much more versatile functional molecules than we ever thought. Also, genes that are exclusively expressed in mast cells have been identified in comparison with other cell types. In this article, the outcome of microarray-based analyses on the role of mast cells in allergic inflammation will be reviewed by focusing on the mast cell-specific genes as drug targets.

Culture of human mast cells from peripheral blood progenitors

This protocol details a method for obtaining a considerable number of human mast cells from peripheral blood cells from normal donors without using stem cell mobilization treatment. By using the magnetic cell sorting system, 10(4)-10(5) cells are retrieved in the CD34+ fraction when 100 ml of blood is drawn from a healthy donor. When these cells are cultured using methylcellulose medium supplemented with stem cell factor and interleukin 6, 10(3)-10(4) mast cell colonies are formed in 6 weeks. The total mast cell number at 6 weeks of culture will be 10(6)-10(7).

Link between TRPV channels and mast cell function

Mast cells are tissue-resident immune effector cells. They respond to diverse stimuli by releasing potent biological mediators into the surrounding tissue, and initiating inflammatory responses that promote wound healing and infection clearance. In addition to stimulation via immunological routes, mast cells also respond to polybasic secretagogues and physical stimuli. Each mechanism for mast cell activation relies on the influx of calcium through specific ion channels in the plasma membrane. Recent reports suggest that several calcium-permeant cation channels of the TRPV family are expressed in mast cells. TRPV channels are a family of sensors that receive and react to chemical messengers and physical environmental cues, including thermal, osmotic, and mechanical stimuli. The central premise of this review is that TRPVs transduce physiological and pathophysiological cues that are functionally coupled to calcium signaling and mediator release in mast cells. Inappropriate mast cell activation is at the core of numerous inflammatory pathologies, rendering the mast cell TRPV channels potentially important therapeutic targets.

Gene expression profiling of human mast cell subtypes: an in silico study

BACKGROUND

Human mast cells (MCs) were classified into at least two subtypes, i.e., tryptase- and chymase-positive MCs (MC(TC)) and tryptase-only-positive MCs (MC(T)). However, differences in global molecular expression between these subtypes are unknown.

METHODS

We analyzed public microarray data of MC subtypes derived from various tissues and those of peripheral blood granulocytes by using hierarchical clustering methods to understand the global gene expression profiles.

RESULTS

All the transcripts subjected to this clustering analysis were classified into two large clusters, i.e., MC-preferential or granulocyte-preferential. In the original works, MCs from tonsil, lung and skin had been cultured for more than several weeks to obtain highly viable and pure cell populations, and these MCs retained their typical profiles such as intensities of chymase protein expression. Most of the transcripts were commonly expressed by these MC subtypes. However, tonsil-derived MCs and skin-derived MCs but not lung-derived MCs expressed high levels of chymase (CMA1) as expected for the properties of MC(TC) and MC(T). These CMA1-high MCs and CMA1-low MCs respectively expressed distinct sets of transcripts as small gene clusters as well as CMA-1 even after being cultured in the absence of a tissue environment.

CONCLUSIONS

The MC lineage seems to be far from the granulocyte lineages including basophils. CMA1-high MCs (MC(TC)) and CMA1-low MCs (MC(T)) can be regarded as differentiated MC subtypes. As such, importance of data analysis studies will be increasing along with the accumulation of global molecular data in the public database.

Oxidized LDL induces a coordinated up-regulation of the glutathione and thioredoxin systems in human macrophages

Using DNA microarray analysis, we found that human macrophages respond to oxidized low-density lipoprotein (oxLDL) by activating the antioxidative glutathione and thioredoxin systems. Several genes of the glutathione and thioredoxin systems were expressed at high levels in macrophages when compared to 80 other human tissues and cell types, indicating that these systems may be of particular importance in macrophages. The up-regulation of three genes in these systems, thioredoxin (P < 0.005), thioredoxin reductase 1 (P < 0.001) and glutathione reductase (P < 0.001) was verified with real-time RT-PCR, using human macrophages from 10 healthy donors. To investigate the possible role of these antioxidative systems in the development of atherosclerosis, expression levels in macrophages from 15 subjects with atherosclerosis (12 men, 3 women) and 15 matched controls (12 men, 3 women) were analyzed using DNA microarrays. Two genes in the glutathione system Mn superoxide dismutase (P < 0.05) and catalase (P < 0.05) differed in expression between the groups. We conclude that macrophage uptake of oxidized LDL induces a coordinated up-regulation of genes of the glutathione and thioredoxin systems, suggesting that these systems may participate in the cellular defense against oxidized LDL and possibly modulate the development of atherosclerosis.

Identification of tryptase- and chymase-related gene clusters in human mast cells using microarrays

Tryptase and chymase are the two major granular proteases present in human mast cell (MC)s. We used oligonucleotide microarray to measure the levels of approximately 22,000 transcripts in cord blood-derived MCs at 4 weeks, 8 weeks, 12 weeks and 18 weeks in culture. Tryptase (TPSB2) was expressed at the highest level among all transcripts and its expression level reached a plateau at 8 weeks. On the other hand, the expression level of chymase (CMAI) doubled every 4-6 weeks. A similar tendency was found at the protein levels with FACS analysis. After filtering the transcripts with MC-specificity, hierarchical clustering analysis identified 494 and 81 transcripts in the same clusters with tryptase and chymase, respectively. MC-specific genes, KIT and HDC were found in the tryptase cluster. In the chymase cluster, a critical suppressor for cell senescence, BMI1 and the several related genes were found, suggesting that chymase expression may be closely related to cell senescence/quiescence events.

Differential expression of genes involved in skin homing, proliferation, and apoptosis in CD4+ T cells of patients with atopic dermatitis

CD4+ T cells play a critical role in allergic diseases, both in the affected tissue as well as systemically. Our objective was to investigate the in vivo activation state of peripheral blood CD4+ T cells of atopic dermatitis (AD) patients by analyzing gene expression profiles of unstimulated CD4+ T cells. mRNA samples from blood CD4+ T cells, isolated from five AD patients and seven healthy controls (HC), were analyzed using oligonucleotide arrays. Differentially regulated genes were validated by quantitative PCR (Q-PCR) in a larger group of patients with AD, in a group of patients with allergic asthma (AA), and HC subjects. In addition, "typical" T helper type 1 (Th1)- and Th2-related genes were analyzed by Q-PCR. Microarray analysis revealed differential expression of 52 genes in AD patients. Q-PCR confirmed several differentially regulated genes in AD, including CCR10, CRTH2, C-JUN, and NR4A2. Two groups of genes with highly correlating gene expression levels involved in tissue homing and proliferation or apoptosis, respectively, were identified. No marked differences were found in gene expression levels of typical Th1 or Th2 genes in AD or in AA patients. This study demonstrates that peripheral blood, unstimulated CD4+ T cells in AD patients show differentially expressed genes involved in tissue homing, proliferation, and apoptosis. No marked expression differences of "typical" atopy genes were found.

Anti-inflammatory potential of CB1-mediated cAMP elevation in mast cells

Cannabinoids are broadly immunosuppressive, and anti-inflammatory properties have been reported for certain marijuana constituents and endogenously produced cannabinoids. The CB2 cannabinoid receptor is an established constituent of immune system cells, and we have recently established that the CB1 cannabinoid receptor is expressed in mast cells. In the present study, we sought to define a role for CB1 in mast cells and to identify the signalling pathways that may mediate the suppressive effects of CB1 ligation on mast cell activation. Our results show that CB1 and CB2 mediate diametrically opposed effects on cAMP levels in mast cells. The observed long-term stimulation of cAMP levels by the Galpha(i/o)-coupled CB1 is paradoxical, and our results indicate that it may be attributed to CB1-mediated transcriptional regulation of specific adenylate cyclase isoenzymes that exhibit superactivatable kinetics. Taken together, these results reveal the complexity in signalling of natively co-expressed cannabinoid receptors and suggest that some anti-inflammatory effects of CB1 ligands may be attributable to sustained cAMP elevation that, in turn, causes suppression of mast cell degranulation.

Clues to asthma pathogenesis from microarray expression studies

Asthma is a chronic inflammatory disease characterized by airway hyperresponsiveness (AHR), tissue remodeling, and airflow obstruction. The pathogenesis of asthma is only partly understood, and there is an urgent need for improved therapeutic strategies for this disease. Microarray technology has considerable promise as a tool for discovery of novel asthma therapeutic targets, although the field is still in its infancy. A number of studies have described expression profiles derived from human asthmatic lung tissue, mouse airway tissue, or from key cell types associated with asthma, but to date relatively few studies have exploited these findings to discover new pathways involved in the pathogenesis of asthma. Among the genes to have been identified by array studies and validated by further studies are monokine induced by interferon (IFN)-gamma, fatty acid binding proteins (FABP), and complement factor 5 (C5). Here we provide examples of microarray approaches to the discovery of new molecules associated with asthma. We anticipate that these types of analyses will provide considerable insight into asthma pathogenesis and will provide a wealth of new molecules for downstream analyses such as gene deficient mouse studies, or monoclonal antibody production.

Reduction of macrophage infiltration and chemoattractant gene expression changes in white adipose tissue of morbidly obese subjects after surgery-induced weight loss

In human obesity, the stroma vascular fraction (SVF) of white adipose tissue (WAT) is enriched in macrophages. These cells may contribute to low-grade inflammation and to its metabolic complications. Little is known about the effect of weight loss on macrophages and genes involved in macrophage attraction. We examined subcutaneous WAT (scWAT) of 7 lean and 17 morbidly obese subjects before and 3 months after bypass surgery. Immunomorphological changes of the number of scWAT-infiltrating macrophages were evaluated, along with concomitant changes in expression of SVF-overexpressed genes. The number of scWAT-infiltrating macrophages before surgery was higher in obese than in lean subjects (HAM56+/CD68+; 22.6 +/- 4.3 vs. 1.4 +/- 0.6%, P < 0.001). Typical "crowns" of macrophages were observed around adipocytes. Drastic weight loss resulted in a significant decrease in macrophage number (-11.63 +/- 2.3%, P < 0.001), and remaining macrophages stained positive for the anti-inflammatory protein interleukin 10. Genes involved in macrophage attraction (monocyte chemotactic protein [MCP]-1, plasminogen activator urokinase receptor [PLAUR], and colony-stimulating factor [CSF]-3) and hypoxia (hypoxia-inducible factor-1alpha [HIF-1alpha]), expression of which increases in obesity and decreases after surgery, were predominantly expressed in the SVF. We show that improvement of the inflammatory profile after weight loss is related to a reduced number of macrophages in scWAT. MCP-1, PLAUR, CSF-3, and HIF-1alpha may play roles in the attraction of macrophages in scWAT.

[Application to allergic diseases]

The increasing prevalence of allergic diseases in developed countries is considered to be caused, at least in part, by rapid improvement of human hygiene. In human beings, the immune system developed as an ingenious device for defending against frequent attacks by microbes. Therefore, our immune system seems to have become deranged in our recent, unprecedentedly hygienic environment. It is now necessary to understand the total functional elements comprising the immune system, not just a single molecule present in an immunocyte working in our immune system. Microarray analysis is now becoming capable of detecting the whole transcripts present in a cell. It is anticipated that we can understand the deranged human immunity using the system biology. It is also expected to predict previously unexpected drug-related adverse events caused by interaction of a drug with responsible molecules present in vital organs.

A target selection of somatic hypermutations is regulated similarly between T and B cells upon activation-induced cytidine deaminase expression

Activation-induced cytidine deaminase (AID) is essential for somatic hypermutations (SHM) and class switch recombination. Overexpression of AID in non-B cells can induce SHM in artificial constructs inserted in various loci in the genome. AID overexpression was thus proposed to introduce mutations in a wide variety of genes with little specificity. We previously showed that AID transgenic mice developed T cell lymphomas in which the variable region beta genes of the T cell receptor and c-myc were mutated as frequently as SHM in activated B cells. To understand the target specificity of SHM in AID-expressing T lymphomas, we sequenced six oncogenes (c-myc, pim1, p53, atm, tgfbr-2, and k-ras) and two genes (cd4 and cd5) that are actively transcribed in T lymphomas. SHM was found only in c-myc, pim1, cd4, and cd5, which share the E47 binding motif in the enhancer/promoter. The rest that are not mutated in B cells were not mutated in AID-induced T lymphomas either, although they are transcribed in T and B cells. Comparison of several features of SHM, including selection of targets and mutation distribution, suggests that the regulatory mechanism of SHM is similar between T and B cells. SHM base specificities in the CD4 and CD5 genes were biased to AT, indicating that the preference of target bases of the mutations generated by overexpression of AID is not always GC bases but variable between target genes.

A family of fatty acid binding receptors

The family of G protein-coupled receptors (GPCRs) serves as the target for almost a third of currently marketed drugs, and provides the predominant mechanism through which extracellular factors transmit signals to the cell. The discovery of GPCRs with no known ligand has initiated a frenzy of research, with the aim of elucidating the physiological ligands for these "orphan" receptors and revealing new drug targets. The GPR40 family of receptors, tandemly located on chromosome 19q13.1, exhibit 30-40% homology to one another and diverse tissue distribution, yet all are activated by fatty acids. Since agonists of GPR40 are medium to longchain fatty acids and those for GPR41 and 43 are short-chain fatty acids, the family clearly provides an intriguing example of how the ligand specificity, patterns of expression, and function of GPCRs can diverge through evolution. Here we summarize the identification, structure, and pharmacology of the receptors and speculate on the respective physiological roles that the GPR40 family members may play.

The cell cycle associated protein, HTm4, is expressed in differentiating cellsof the hematopoietic and central nervous system in mice

HTm4 is a member of a newly defined family of human and murine proteins, the MS4 (membrane-spanning four) protein group, which has a distinctive four-transmembrane structure. MS4 protein functions include roles as cell surface signaling receptors and intracellular adapter proteins. We have previously demonstrated that HTm4 regulates the function of the KAP phosphatase, a key regulator of cell cycle progression. In humans, the expression of HTm4 is largely restricted to cells of the hematopoietic lineage, possibly reflecting a causal role for this molecule in differentiation/proliferation of hematopoietic lineage cells. In this study, we show that, like the human homologue, murine HTm4 is also predominantly a hematopoietic protein with distinctive expression patterns in developing murine embryos and in adult animals. In addition, we observed that murine HTm4 is highly expressed in the developing and adult murine nervous system, suggesting a previously unrecognized role in central and peripheral nervous system development.

Differential gene expression profile between cord blood progenitor-derived and adult progenitor-derived human mast cells

In order to better understand the mechanisms governing the display of mast cell characteristics in human mast cells (MCs), such as cord blood (CB)-derived cultured mast cells, peripheral blood (PB)-derived cultured MCs, and differentiated adult-lung cultured MCs, we examined the transcriptomes of these three types MCs using oligonucleotide microarray (GeneChip) and hierarchical clustering analysis. The expression profile of CB-derived MCs substantially differed from those of PB- and lung-derived MCs. In CB-derived MCs, we identified 132 up-regulated transcripts, such as MARCKS, KRT1, TIMP2, SERPINA1, and TLR2, and 428 down-regulated transcripts, such as LTBP3, CDC42BPA, DDO, DICER1, and FCER1A. Moreover, using RT-PCR and FACS analysis, we confirmed the expression of TLR2, which plays an important role in innate immunity, in CB-derived MCs but not in PB-derived MCs. In addition, it was observed that CB-derived MCs uniquely release histamine and CCL1, which are produced by human MCs but not by human monocytes, in response to peptidoglycan (PGN), although it had been controversy issue whether CB-derived MCs could, in fact, induce degranulation in response to PGN. These results indicated that in innate immunity MCs derived from neonatal hemopoietic cells might have unique functions compared to their adult counterparts because of different gene profiles.