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

Urinary SPP1 has potential as a non-invasive diagnostic marker for focal segmental glomerulosclerosis

Focal segmental glomerulosclerosis (FSGS) is a type of chronic glomerular nephropathy showing characteristic glomerular sclerosis, diagnosed by kidney biopsy. However, it is difficult and expensive to monitor disease progression with repeated renal biopsy in clinical practice, and thus here we explored the feasibility of urine biomarkers as non-invasive diagnostic tools. We downloaded scRNA-seq datasets of 20 urine cell samples and 3 kidney tissues and obtained two gene lists encoding extracellular proteins for bioinformatic analysis; in addition, we identified key EP-Genes by immunohistochemical staining and performed bulk RNA sequencing with 12 urine samples. We report that urine cells and kidney cells were correlated. A total of 64 EP-Genes were acquired by intersecting genes of distal tubular cluster with extracellular proteins. Function enrichment analysis showed that EP-Genes might be involved in the immune response and extracellular components. Six key EP-Genes were identified and correlated with renal function. IMC showed that key EP-Genes were located mainly in tubules. Cross verification and examination of a urine RNAseq dataset showed that SPP1 had diagnostic potential for FSGS. The presence of urine SPP1 was primarily associated with macrophage infiltration in kidney, and the pathogenesis of FSGS may be related to innate immunity. Urinary cells seemed to be strongly similar to kidney cells. In summary, SPP1 levels reflect renal function and may have potential as a biomarker for non-invasive diagnosis of FSGS.

Degranulation of human mast cells: modulation by P2 receptors' agonists

Since the late 1970s, there has been an alarming increase in the incidence of asthma and its morbidity and mortality. Acute obstruction and inflammation of allergic asthmatic airways are frequently caused by inhalation of exogenous substances such as allergens cross-linking IgE receptors expressed on the surface of the human lung mast cells (HLMC). The degree of constriction of human airways produced by identical amounts of inhaled allergens may vary from day to day and even hour to hour. Endogenous factors in the human mast cell (HMC)'s microenvironment during allergen exposure may markedly modulate the degranulation response. An increase in allergic responsiveness may significantly enhance bronchoconstriction and breathlessness. This review focuses on the role that the ubiquitous endogenous purine nucleotide, extracellular adenosine 5'-triphosphate (ATP), which is a component of the damage-associated molecular patterns, plays in mast cells' physiology. ATP activates P2 purinergic cell-surface receptors (P2R) to trigger signaling cascades resulting in heightened inflammatory responses. ATP is the most potent enhancer of IgE-mediated HLMC degranulation described to date. Current knowledge of ATP as it relates to targeted receptor(s) on HMC along with most recent studies exploring HMC post-receptor activation pathways are discussed. In addition, the reviewed studies may explain why brief, minimal exposures to allergens (e.g., dust, cat, mouse, and grass) can unpredictably lead to intense clinical reactions. Furthermore, potential therapeutic approaches targeting ATP-related enhancement of allergic reactions are presented.

Characterization of human umbilical cord blood-derived mast cells using high-throughput expression profiling and next-generation knowledge discovery platforms

Mast cells (MCs) are tissue-resident innate immune cells that express the high-affinity receptor for immunoglobulin E and are responsible for host defense and an array of diseases related to immune system. We aimed in this study to characterize the pathways and gene signatures of human cord blood-derived MCs (hCBMCs) in comparison to cells originating from CD34- progenitors using next-generation knowledge discovery methods. CD34+ cells were isolated from human umbilical cord blood using magnetic activated cell sorting and differentiated into MCs with rhIL-6 and rhSCF supplementation for 6-8 weeks. The purity of hCBMCs was analyzed by flow cytometry exhibiting the surface markers CD117+CD34-CD45-CD23-FcεR1αdim. Total RNA from hCBMCs and CD34- cells were isolated and hybridized using microarray. Differentially expressed genes were analyzed using iPathway Guide and Pre-Ranked Gene Set Enrichment Analysis. Next-generation knowledge discovery platforms revealed MC-specific gene signatures and molecular pathways enriched in hCBMCs and pertain the immunological response repertoire.

Do Mast Cells Contribute to the Antifungal Host Defense?

The fungal kingdom includes a group of microorganisms that are widely distributed in the environment, and therefore the exposure to them is almost constant. Furthermore, fungal components of the microbiome, i.e., mycobiome, could serve as a reservoir of potentially opportunistic pathogens. Despite close encounters with fungi, defense mechanisms that develop during fungal infections remain unexplored. The strategic location of mast cells (MCs) close to the external environment places them among the first cells to encounter pathogens along with the other innate immune cells. MCs are directly involved in the host defense through the ability to destroy pathogens or indirectly by activating other immune cells. Most available data present MCs’ involvement in antibacterial, antiviral, or antiparasitic defense mechanisms. However, less is known about their contribution in defense mechanisms against fungi. MCs may support immune responses to fungi or their specific molecules through initiated degranulation, synthesis and release of cytokines, chemokines, mediators, and generation of reactive oxygen species (ROS), as well as immune cells’ recruitment, phagocytosis, or provision of extracellular DNA traps. This review summarizes current knowledge on host defense mechanisms against fungi and MCs’ involvement in those processes. It also describes the effects of fungi or fungus-derived constituents on MCs’ activity.

Mannan activates tissue native and IgE-sensitized mast cells to proinflammatory response and chemotaxis in TLR4-dependent manner

Mast cells take part in host defense against microorganisms as they are numerous at the portal of infection, exert several essential mechanisms of pathogen destruction, and they express pattern recognition receptors. Accumulating evidence indicates that these cells are involved in the control and clearance of bacterial, viral, or parasitic infections, but much less is known about their contribution in defense against fungi. The study was aimed to establish whether mannan, which comprises an outermost layer and major structural constituent of the fungal cell wall, may directly stimulate tissue mast cells to the antifungal response. Our findings indicate that mannan activates mast cells isolated from the rat peritoneal cavity to initiate the proinflammatory response. We found that mannan stimulates mast cells to release histamine and to generate cysteinyl leukotrienes, cytokines (IFN-γ, GM-CSF, TNF), and chemokines (CCL2, CCL3). It also increased the mRNA expression of various cytokines/chemokines. We also documented that mannan strongly activates mast cells to generate reactive oxygen species and serves as a potent chemoattractant for these cells. Furthermore, we established that mannan-induced activity of mast cells is mediated via TLR4 with the involvement of the spleen tyrosine kinase molecule. Taking together, our results clearly support the idea that mast cells act as sentinel cells and crucially determine the course of the immune response during fungal infection. Additionally, presented data on IgE-coated mast cells suggest that exposure to fungal mannan could influence the severity of IgE-dependent diseases, including allergic ones.

Expression of surface and intracellular Toll-like receptors by mature mast cells

Nowadays, more and more data indicate that mast cells play an important role in host defense against pathogens. That is why it is essential to understand the expression of Toll-like receptors (TLRs) by mast cells, because these molecules play particularly significant role in initiation host defense against microorganisms as they recognize both wide range of microbial pathogen-associated molecular patterns (PAMPs) and various endogenous damage-associated molecular patterns (DAMPs) released in response to infection. Therefore, we examined the constitutive expression of both surface and endosomal TLRs in rat native fully mature tissue mast cells. By the use of qRT-PCR we found that these cells express mRNAs for TLR2, TLR3, TLR4, TLR5, TLR7, and TLR9. The expression of TLR3, TLR4, TLR5, TLR7, and TLR9 transcripts were low and comparable and only the expression of TLR2 transcript was significant. By the use of flow cytometry technique, we clearly documented that mast cells express TLR2, TLR4, and TLR5 on cell surface, while TLR3, TLR7, and TLR9 proteins are located both on the cell membrane and intracellularly. The highest expression was observed for TLR5 and the lowest for surface TLR7. These observations undoubtedly indicate that mature tissue mast cells have a broad set of TLR molecules, thus can recognize and bind bacterial, viral, and fungal PAMPs as well as various endogenous molecules generated in response to infection.

Mast cells in asthma--state of the art

Mast cells (MCs) play a central role in tissue homoeostasis, sensing the local environment through numerous innate cell surface receptors. This enables them to respond rapidly to perceived tissue insults with a view to initiating a co-ordinated programme of inflammation and repair. However, when the tissue insult is chronic, the ongoing release of multiple pro-inflammatory mediators, proteases, cytokines and chemokines leads to tissue damage and remodelling. In asthma, there is strong evidence of ongoing MC activation, and their mediators and cell-cell signals are capable of regulating many facets of asthma pathophysiology. This article reviews the evidence behind this.

Role of MARCKS in regulated secretion from mast cells and airway goblet cells

MARCKS (myristoylated alanine-rich C kinase substrate) is postulated to regulate the passage of secretory granules through cortical actin in the early phase of exocytosis. There are, however, three proposed mechanisms of action, all of which were derived from studies using synthetic peptides representing either the central phosphorylation site domain or the upstream, NH2-terminal domain: it tethers actin to the plasma membrane and/or to secretory granules, and/or it sequesters PIP2. Using MARCKS-null mice, we probed for a loss of function secretory phenotype in mast cells harvested from embryonic livers and maturated in vivo [embryonic hepatic-derived mast cells (eHMCs)]. Both wild-type (WT) and MARCKS-null eHMCs exhibited full exocytic responses upon FcϵRI receptor activation with DNP-BSA (2,4-dinitrophenyl-BSA), whether they were in suspension or adherent. The secretory responses of MARCKS-null eHMCs were consistently higher than those of WT cells, but the differences had sporadic statistical significance. The MARCKS-null cells exhibited faster secretory kinetics, however, achieving the plateau phase of the response with a t½ ∼2.5-fold faster. Hence, MARCKS appears to be a nonessential regulatory protein in mast cell exocytosis but exerts a negative modulation. Surprisingly, the MARCKS NH2-terminal peptide, MANS, which has been reported to inhibit mucin secretion from airway goblet cells (Li Y, Martin LD, Spizz G, Adler KB. J Biol Chem 276: 40982-40990, 2001), inhibited hexosaminidase secretion from WT and MARCKS-null eHMCs, leading us to reexamine its effects on mucin secretion. Results from studies using peptide inhibitors with human bronchial epithelial cells and with binding assays using purified mucins suggested that MANS inhibited the mucin binding assay, rather than the secretory response.

Comparison of long noncoding RNA and mRNA expression profiles in mesenchymal stem cells derived from human periodontal ligament and bone marrow

Mesenchymal stem cells (MSCs) in different anatomic locations possess diverse biological activities. Maintaining the pluripotent state and differentiation depend on the expression and regulation of thousands of genes, but it remains unclear which molecular mechanisms underlie MSC diversity. Thus, potential MSC applications are restricted. Long noncoding RNAs (lncRNAs) are implicated in the complex molecular circuitry of cellular processes. We investigated differences in lncRNA and mRNA expression profiles between bone marrow stem cells (BMSCs) and periodontal ligament stem cells (PDLSCs) with lncRNA microarray assays and bioinformatics analysis. In PDLSCs, numerous lncRNAs were significantly upregulated (n = 457) or downregulated (n = 513) compared to BMSCs. Furthermore, 1,578 mRNAs were differentially expressed. These genes implicated cellular pathways that may be associated with MSC characteristics, including apoptosis, MAPK, cell cycle, and Wnt signaling pathway. Signal-net analysis indicated that phospholipase C beta 4, filamin B beta, calcium/calmodulin-dependent protein kinase II gamma, and the ionotropic glutamate receptor, AMPA 1, had the highest betweenness centrality among significant genes in the differential gene profile network. A comparison between the coding-noncoding gene coexpression networks of PDLSCs and BMSCs identified chemokine (C-X-C motif) ligand 12 as a core regulatory factor in MSC biology. These results provided insight into the mechanisms underlying MSC biology.

Analysis of gene expression during odontogenic differentiation of cultured human dental pulp cells

OBJECTIVES

We analyzed gene-expression profiles after 14 day odontogenic induction of human dental pulp cells (DPCs) using a DNA microarray and sought candidate genes possibly associated with mineralization.

MATERIALS AND METHODS

Induced human dental pulp cells were obtained by culturing DPCs in odontogenic induction medium (OM) for 14 day. Cells exposed to normal culture medium were used as controls. Total RNA was extracted from cells and analyzed by microarray analysis and the key results were confirmed selectively by reverse-transcriptase polymerase chain reaction (RT-PCR). We also performed a gene set enrichment analysis (GSEA) of the microarray data.

RESULTS

Six hundred and five genes among the 47,320 probes on the BeadChip differed by a factor of more than two-fold in the induced cells. Of these, 217 genes were upregulated, and 388 were down-regulated. GSEA revealed that in the induced cells, genes implicated in Apoptosis and Signaling by wingless MMTV integration (Wnt) were significantly upregulated.

CONCLUSIONS

Genes implicated in Apoptosis and Signaling by Wnt are highly connected to the differentiation of dental pulp cells into odontoblast.

Reciprocal modulation of anti-IgE induced histamine release from human mast cells by A₁ and A(2B) adenosine receptors

BACKGROUND AND PURPOSE

Adenosine is believed to participate in the pathological development of asthma through a mast cell-dependent mechanism. Our study aimed to pharmacologically characterize the functions of adenosine receptor (AR) subtypes (A₁, A(2A) , A(2B) and A₃) in primary human cultured mast cells (HCMC).

EXPERIMENTAL APPROACH

HCMC were derived from progenitor stem cells in buffy coat and the effects of adenosine receptor ligands on basal and IgE-dependent histamine release were evaluated.

KEY RESULTS

Adenosine and analogues alone did not induce HCMC degranulation. When HCMC were activated by anti-IgE after 10 min pre-incubation with adenosine, a biphasic effect on histamine release was observed with enhancement of HCMC activation at low concentrations of adenosine (10⁻⁹-10⁻⁷ mol·L⁻¹) and inhibition at higher concentrations (10⁻⁶-10⁻⁴ mol·L⁻¹). The potentiating action was mimicked by A₁ AR agonists CCPA and 2'MeCCPA, and inhibited by the A₁ AR antagonist PSB36. In contrast, the inhibitory action of adenosine was mimicked by the non-specific A₂ AR agonist CV1808 and attenuated by A(2B) AR antagonists PSB1115 and MRS1760. The non-selective AR antagonist CGS15943 attenuated both the potentiating and inhibitory actions.

CONCLUSIONS AND IMPLICATIONS

We have defined for the first time the contribution of A₁ and A(2B) ARs, respectively, to the potentiating and inhibitory action of adenosine on human mast cell activation. With reference to the current trend of developing novel anti-asthmatic agents from AR ligands, our results suggest that inhibition of human mast cell activation would be a mechanism for A₁ AR antagonists, but not A(2B) AR antagonists.

Gene expression profile in mesenchymal stem cells derived from dental tissues and bone marrow

Purpose

The aim of this study is to compare the gene expression profile in mesenchymal stem cells derived from dental tissues and bone marrow for characterization of dental stem cells.

Methods

We employed GeneChip analysis to the expression levels of approximately 32,321 kinds of transcripts in 5 samples of bone-marrow-derived mesenchymal stem cells (BMSCs) (n=1), periodontal ligament stem cells (PDLSCs) (n=2), and dental pulp stem cells (DPSCs) (n=2). Each cell was sorted by a FACS Vantage Sorter using immunocytochemical staining of the early mesenchymal stem cell surface marker STRO-1 before the microarray analysis.

Results

We identified 379 up-regulated and 133 down-regulated transcripts in BMSCs, 68 up-regulated and 64 down-regulated transcripts in PDLSCs, and 218 up-regulated and 231 down-regulated transcripts in DPSCs. In addition, anatomical structure development and anatomical structure morphogenesis gene ontology (GO) terms were over-represented in all three different mesenchymal stem cells and GO terms related to blood vessels, and neurons were over-represented only in DPSCs.

Conclusions

This study demonstrated the genome-wide gene expression patterns of STRO-1⁺ mesenchymal stem cells derived from dental tissues and bone marrow. The differences among the expression profiles of BMSCs, PDLSCs, and DPSCs were shown, and 999 candidate genes were found to be definitely up- or down-regulated. In addition, GOstat analyses of regulated gene products provided over-represented GO classes. These data provide a first step for discovering molecules key to the characteristics of dental stem cells.

Mast cells in lung inflammation

Mast cells play an important role in the lung in both health and disease. Their primary role is to initiate an appropriate program of inflammation and repair in response to tissue damage initiated by a variety of diverse stimuli. They are important for host immunity against bacterial infection and potentially in the host immune response to non small cell lung cancer. In situations of ongoing tissue damage, the sustained release of numerous pro-inflammatory mediators, proteases and cytokines, contributes to the pathophysiology of lung diseases such as asthma and interstitial lung disease. A key goal is the development of treatments which attenuate adverse mast cell function when administered chronically to humans in vivo. Such therapies may offer a novel approach to the treatment of many life-threatening diseases.

Surface TLR2 and TLR4 expression on mature rat mast cells can be affected by some bacterial components and proinflammatory cytokines

The aim of our study was to determine whether some bacterial components as well as some proinflammatory cytokines can affect surface mast cell levels. By the use of flow cytometry technique, we documented that freshly isolated mature rat peritoneal mast cells do express surface TLR2 and TLR4 protein, but not CD14 molecules, and respond to stimulation with TLR2 and TLR4 ligands by cysteinyl leukotriene generation. The level of TLR2 protein is modulated by PGN and CCL5 treatment, but not by LPS, LAM, TNF, or IL-6. Surface mast cell TLR4 expression is affected by LPS, LAM, IL-6, and CCL5. Considering that TLR-mediated activation conditions not only engaged these cells in antibacterial defense and development of inflammation but also might influence allergic processes, our observations that surface TLR2 and TLR4 expression can be regulated both bacterial components and proinflammatory cytokines seem to be very intriguing and importance.

Characterization of gene expression profiles for different types of mast cells pooled from mouse stomach subregions by an RNA amplification method

Background

Mast cells (MCs) play pivotal roles in allergy and innate immunity and consist of heterogenous subclasses. However, the molecular basis determining the different characteristics of these multiple MC subclasses remains unclear.

Results

To approach this, we developed a method of RNA extraction/amplification for intact in vivo MCs pooled from frozen tissue sections, which enabled us to obtain the global gene expression pattern of pooled MCs belonging to the same subclass. MCs were isolated from the submucosa (sMCs) and mucosa (mMCs) of mouse stomach sections, respectively, 15 cells were pooled, and their RNA was extracted, amplified and subjected to microarray analysis. Known marker genes specific for mMCs and sMCs showed expected expression trends, indicating accuracy of the analysis.

We identified 1,272 genes showing significantly different expression levels between sMCs and mMCs, and classified them into clusters on the basis of similarity of their expression profiles compared with bone marrow-derived MCs, which are the cultured MCs with so-called 'immature' properties. Among them, we found that several key genes such as Notch4 had sMC-biased expression and Ptgr1 had mMC-biased expression. Furthermore, there is a difference in the expression of several genes including extracellular matrix protein components, adhesion molecules, and cytoskeletal proteins between the two MC subclasses, which may reflect functional adaptation of each MC to the mucosal or submucosal environment in the stomach.

Conclusion

By using the method of RNA amplification from pooled intact MCs, we characterized the distinct gene expression profiles of sMCs and mMCs in the mouse stomach. Our findings offer insight into possible unidentified properties specific for each MC subclass.

Generation and characterization of novel canine malignant mast cell line CL1

Studies using the currently available malignant canine mast cell lines and bone marrow-derived cultured mast cells (BMCMCs) have provided an in-depth understanding of normal and neoplastic canine mast cell biology. However, many of the currently available malignant canine mast cell lines possess limitations, including loss of cell surface markers and inability to bind canine IgE. We have recently generated a novel mast cell line, CL1, from an 11-year-old spayed female Labrador retriever diagnosed with systemic mastocytosis and neoplastic effusion. The CL1 cells express KIT, FcepsilonRI, CD44, CD45, CD14, CD11a, CD11b and CD18 as well as chymase. Interestingly, these cells express wild-type KIT, with no evidence of autophosphorylation, but are able to proliferate independently without the addition of exogenous stem cell factor (SCF), KIT ligand. However, stimulation of CL1 cells with SCF induces KIT phosphorylation promoting cell proliferation. The CL1 cells retain functional properties of mast cells, degranulating in a dose-dependent manner in response to both IgE cross-linking and chemical stimulation. Lastly, cytogenetic evaluation revealed several recurrent tumor-associated chromosome copy number imbalances in the CL1 line. In summary, the CL1 cell line possesses phenotypic and functional properties similar to those found in canine BMCMCs, and will likely be a useful tool to study mast cell biology, factors regulating transformation of mast cells, cytogenetic abnormalities in mast cell tumors, and novel preclinical therapies.

Assays of MSCs with microarrays

The rapid development of microarray technology during the last decade has greatly expanded the ability to define the genes expressed in cells. This chapter will focus on describing the steps required for conducting successful microarray experiments with multipotential stromal cells (MSCs). A complete microarray experiment, using the Affymetrix system, will be described starting from experimental design and ending with examples of data analysis using the dChip program.

Seven week culture of functional human mast cells from buffy coat preparations

Functional, mature human mast cells have been generated by in vitro differentiation of CD133(+)/CD34(+) progenitor cells isolated from e.g. cord blood, peripheral blood, bone marrow or fetal liver. However, the protocols published so far require long term cultivation, i.e. up to 15 weeks for mast cell differentiation, which makes such approaches not only laborious but also costly. Here, we have developed a protocol for generating functional human mast cells from peripheral blood already within 7 weeks. Human CD133(+) progenitors were isolated from buffy coat preparations of peripheral blood and cultured in the presence of stem cell factor (SCF) and IL-6 for 7 weeks. IL-3 was added to the culture medium during the first 3 weeks, and fetal calf serum (FCS) added during the last week. In vitro differentiated CD133(+) cells exhibited multiple characteristics of mature mast cells. Thus, cells contained tryptase and expressed functional levels of FcepsilonRI. Anti-IgE stimulation induced significant release of histamine and PGD(2) and also of chemokines including MCP-1, IL-8, MIP-1alpha, and MIP-1beta. The fact that our in vitro differentiated mast cells are derived from a generally available source of progenitor cells makes this novel protocol widely applicable to any patient group, irrespective of age. Moreover, this progenitor source is more readily available than e.g. bone marrow or cord blood-derived progenitors. Consequently, our protocol has great potential in studies on mast cell biology and mast cell pathology, and e.g. on evaluation of drug effects.

Urticaria Neonatorum: accumulation of tryptase-expressing mast cells in the skin lesions of newborns with Erythema Toxicum

Erythema Toxicum, a rash frequently present in the healthy newborn infant is an innate, immune response to the first commensal micro flora. Flushing and urtication are seen in this manifestation suggesting mast cell (MC) activation and MC derived mediator release. It has recently become evident that MCs participate in the protective, innate immune response against microbes also by secreting products toxic to pathogens such as cathelicidin peptide antibiotics. We hypothesized that MCs contribute to the process of inflammation in Erythema Toxicum and that skin MCs of human newborns express the cathelicidin peptide antibiotic LL-37. Skin sections were immunostained for MC tryptase. Double immunofluorescence was performed by staining LL-37 in combination with tryptase. We studied ultra structure of skin MCs with transmission (TEM) and immunoelectron microscopy (IEM). Seven infants with and six infants without the rash, as well as three adults were included. We found numerous tryptase-expressing MCs recruited around the hair follicles in the lesions of Erythema Toxicum. TEM analysis of MCs exhibited signs of degranulation in the lesion. Neither skin MCs from newborns nor adults did express LL-37 as judged by confocal and IEM. MCs participate in the inflammatory responses of Erythema Toxicum by taking an active part in the immune system of the hair follicle. However, their immunological activity is not linked to the expression of the cathelicidin antimicrobial peptide LL-37. A pivotal role of MCs in the innate, inflammatory response at the site of pathogen invasion during the critical time of perinatal colonization is suggested.

A protocol for generating high numbers of mature and functional human mast cells from peripheral blood

BACKGROUND

Mast cells (MCs) are multi-functional effector cells with an essential role in innate immunity and host defence, and under several pathological conditions, such as allergy. Here, we aimed at defining the culture conditions that would allow efficient generation of mature and functional human MCs from their progenitor cells.

METHODS

Human peripheral blood-derived CD34(+) progenitor cells were cultured in vitro under serum-free conditions with human stem cell factor for 9 weeks. Growth and differentiation of the cells into MCs were optimized by selected cytokines and a combination of hypoxic and normoxic conditions. MCs were phenotypically characterized by immunocytochemistry, their preformed mediators were quantified, and their functional ability to degranulate and release histamine was tested.

RESULTS

On average, 20 x 10(6) mature MCs were generated from 0.5 x 10(6) progenitor cells during 9 weeks of culture, i.e. at least a 40-fold increase in cell number was achieved. The mature MCs had oval-shaped non-lobular nuclei, contained histamine, heparin, tryptase, chymase, and cathepsin G in their secretory granules, and strongly expressed c-kit (CD117) and Fc epsilon receptor I on their surface. Histamine release from the cells could be brought about by IgE-anti-IgE cross-linkage, compound 48/80, substance P, and anaphylatoxin C3a. The MCs remained functional for several weeks after their maturation.

CONCLUSION

This study describes an efficient protocol for generating mature MCs from human peripheral blood with a functional phenotype of connective tissue-type MCs. Use of these cultured human MCs will increase our knowledge and understanding about human MC development and biology in human disease.

The usefulness of post-genomics tools for characterization of the amine cross-talk in mammalian cells

Evidence is growing in favour of a relationship between cancer and chronic inflammation, and particularly of the role of a polyamine and histamine metabolic interplay involved in these physiopathological problems, which are indeed highly complex biological systems. Decodification of the complex inter- and intra-cellular signalling mechanisms that control these effects is not an easy task, which must be helped by systems biology technologies, including new tools for location and integration of database-stored information and predictive mathematical models, as well as functional genomics and other experimental molecular approaches necessary for hypothesis validation. We review the state of the art and present our latest efforts in this area, focused on the amine metabolism field.

Bacterial peptidoglycan breaks down intestinal tolerance via mast cell activation: the role of TLR2 and NOD2

Intestinal microbes are believed to be involved in the pathogenesis of inflammatory bowel disease. Microbes and their products are generally well tolerated by intestinal epithelial cells in the intestinal tract of healthy individuals. It is of significance to understand what breaks down the established tolerance leading to intestinal barrier dysfunction and intestinal inflammation. T84 monolayer transported peptidoglycan (PGN) was determined by enzyme-linked immune assay. Mast cell line HMC-1 cell activation in response to PGN stimulation was observed with electron microscopy and measurement of histamine release. T84 monolayer barrier function was determined by recording the transepithelial electric resistance (TER) and measuring the permeability in response to PGN-induced HMC-1 cell activation. Expression of Toll-like receptor (TLR) 2 and nucleotide-binding oligomerization domain (NOD) 2 were determined by immunocytochemistry, real-time reverse transcription (RT)-PCR and Western blot. Exposure to PGN alone did not alter TER and permeability of T84 monolayers. T84 monolayers transported PGN from the apical chamber to the basal chamber of transwell system. TLR2 expressed on the surface of HMC-1 cells. HMC-1 cells absorbed PGN. HMC-1 cells released histamine in response to the PGN stimulation, which was blocked by pretreatment with antibodies or small interfering RNA against TLR2 or NOD2. In a co-culture system, T84 monolayer transported PGN activated HMC-1 cells and increased the horseradish peroxidase flux. TLR2 mediated the PGN-absorption in HMC-1 cells. Blockade of TLR2 or NOD2 abolished PGN-induced HMC-1 cell activation and T84 monolayer barrier dysfunction. T84 monolayer transported PGN activates HMC-1 cells to release chemical mediators to induce T84 monolayer dysfunction that are mediated by TLR2 and NOD2.

Human tissue mast cells are an inducible reservoir of persistent HIV infection

We have proposed that, unlike other HIV-vulnerable cell lineages, progenitor mast cells (prMCs), cultured in vitro from undifferentiated bone marrow-derived CD34(+) pluripotent progenitors (PPPs), are susceptible to infection during a limited period of their ontogeny. As infected prMCs mature in culture, they lose expression of viral chemokine coreceptors necessary for viral entry and develop into long-lived, latently infected mature tissue mast cells (MCs), resistant to new infection. In vivo recruitment of prMCs to different tissue compartments occurs in response to tissue injury, growth, and remodeling or allergic inflammation, allowing populations of circulating and potentially HIV-susceptible prMCs to spread persistent infection to diverse tissue compartments. In this report, we provide in vivo evidence to confirm this model by demonstrating that HIV-infected women have both circulating prMCs and placental tissue MCs (PLMCs) that harbor inducible infectious HIV even after highly active antiretroviral therapy (HAART) during pregnancy. Furthermore, infectious virus, capable of infecting alloactivated fetal cord blood mononuclear cells (CBMCs), could be induced in isolated latently infected PLMCs after weeks in culture in vitro. These data provide the first in vivo evidence that tissue MCs, developed from infected circulating prMCs, comprise a long-lived inducible reservoir of persistent HIV in infected persons during HAART.

Role of mast cells in allergic and non-allergic immune responses: comparison of human and murine data

The versatile role of mast cells in allergy, in innate immune responses and in the regulation of tissue homeostasis is well recognized. However, it is often not made clear that most mast-cell data derive solely from experiments in mice or rats, species that obviously never suffer from allergic and most other mast-cell-associated human diseases. Data on human mast cells are limited, and the mast-cell source and species from which findings derive are frequently not indicated in the titles and summaries of research publications. This Review summarizes recent data on human mast cells, discusses differences with murine mast cells, and describes new tools to study this increasingly meaningful cell type in humans.

Effects of salmeterol xinafoate and fluticasone propionate on immunological activation of human cultured mast cells

BACKGROUND

The clinical efficacy of combination therapy comprising a long acting beta(2)-agonist (LABA) and corticosteroid is widely recognized for the treatment of adult asthma. Here we examine the effect of salmeterol xinafoate (SX) and fluticasone propionate (FP) alone and in combination on the immunological activation of human cultured mast cells (HCMC)in vitro.

METHODS

HCMC were passively sensitized with IgE antibody and then activated by challenging with anti-IgE antibody. The effect of drugs on the activation of mast cells was examined by measuring the amount of released chemical mediators (histamine, leukotrienes (LT) and prostaglandin D(2) (PGD(2))) and granulocyte macrophage colony stimulating factor (GM-CSF).

RESULTS

The release of each chemical mediator was inhibited by 10-9-10-8M SX but not by 10-10-10-7M FP. The production of GM-CSF was inhibited by a concentration of 10-8M in both drugs and the inhibition was augmented by combined treatment with 10-11M of each drug.

CONCLUSIONS

The immunological release of chemical mediators (histamine, LT, PGD(2)) from HCMC was inhibited by SX but not by FP. SX and FP inhibited the production of GM-CSF by HCMC and both drug showed synergistic inhibition in the production of GM-CSF.

Gene expression differences in normal esophageal mucosa associated with regression and progression of mild and moderate squamous dysplasia in a high-risk Chinese population

A randomized, double-blinded, placebo-controlled 2 x 2 factorial chemoprevention trial was conducted in Linxian, China to assess the effects of selenomethionine and celecoxib on the natural history of esophageal squamous dysplasia. Results from this study indicated that asymptomatic adults with mild dysplasia were more likely to show an improvement when treated with selenomethionine compared with placebo (P = 0.02). Prompted by this finding, we examined the molecular profiles associated with regression and progression of dysplastic lesions in normal mucosa from 29 individuals, a subset of the Linxian cohort, using the Affymetrix U133A chip. Twenty differentially expressed genes were associated with regression and 129 were associated with progression when we compared the change in gene expression over time. Genes associated with immune response (n = 15), cell cycle (n = 15), metabolism (n = 15), calcium transport or calcium ion activity (n = 10), regulation of transcription (n = 9), signal transduction (n = 7), cytoskeleton and microtubules (n = 5), nucleotide processing and biosynthesis (n = 4), G-coupled signaling (n = 4), and apoptosis (n = 3) were present in the list of 149 genes. Using the Expression Analysis Systematic Explorer pathway analysis program, only the immune response pathway was significantly overrepresented among these 149 genes. Individuals whose lesions regressed seemed to have higher expression of genes associated with immune stimulation, such as antigen presentation, survival of T cells, and T-cell activation (HLA-DRA, HLA-DPA1, HLA-DBQ1, CD58, and FCER1A). In contrast, individuals whose lesions progressed had higher expression of genes involved in immune suppression and inflammation (CNR2, NFATC4, NFRKB, MBP, INHBB, CMKLR1, CRP, ORMS, SERPINA7, and SERPINA1). These data suggest that local and systemic immune responses may influence the natural history of esophageal squamous dysplasia.

Generation and characterization of bone marrow-derived cultured canine mast cells

Disorders of mast cells, particularly mast cell tumors (MCTs), are common in dogs. There now is evidence that many of these disorders exhibit breed predilections, suggesting an underlying heritable component. In comparison to humans and mice, little is known regarding the biology of canine mast cells. To facilitate the study of mast cell biology in other species, bone marrow-derived cultured mast cells (BMCMCs) often are used because these represent a ready source of large numbers of cells. We have developed a protocol to successfully generate canine BMCMCs from purified CD34(+) cells. After 5-7 weeks of culture with recombinant canine stem cell factor (rcSCF), greater than 90% of the cell population consisted of mast cells as evidenced by staining with Wright's-Giemsa, as well as production of chymase, tryptase, IL-8 and MCP-1. These cells expressed cell surface markers typical of mast cells including Kit, Fc epsilonRI, CD44, CD45 and CD18/CD11b. The canine BMCMCs were dependent on rcSCF for survival and proliferation, and migrated in response to rcSCF gradients. Cross-linking of cell surface-bound IgE induced the release of histamine and TNFalpha. Histamine release could also be stimulated by ConA, compound 48/80, and calcium ionophore. In summary, canine BMCMCs possess phenotypic and functional properties similar to mast cells found in vivo. These cells represent a novel, valuable resource for investigating normal canine mast cell biology as well as for identifying factors that lead to mast cell dysregulation in the dog.