IgE-dependent activation of human mast cells and fMLP-mediated activation of human eosinophils is controlled by the circadian clock

https://doi.org/10.1016/j.molimm.2014.10.026Get rights and content

Highlights

  • Circadian clock gene expression in mast cells and eosinophils is independent of activation.

  • CXCL8 and CCL2 were released in a circadian manner in response to activation.

  • ERK signaling in mast cells and eosinophils shows circadian rhythm.

  • The circadian clock controls allergic responses rather than vice versa.

Abstract

Symptoms of allergic attacks frequently exhibit diurnal variations. Accordingly, we could recently demonstrate that mast cells and eosinophils – known as major effector cells of allergic diseases – showed an intact circadian clock. Here, we analyzed the role of the circadian clock in the functionality of mast cells and eosinophils. Human intestinal mast cells (hiMC) were isolated from intestinal mucosa; human eosinophils were isolated from peripheral blood. HiMC and eosinophils were synchronized by dexamethasone before stimulation every 4 h around the circadian cycle by FcɛRI crosslinking or fMLP, respectively. Signaling molecule activation was examined using Western blot, mRNA expression by real-time RT-PCR, and mediator release by multiplex analysis. CXCL8 and CCL2 were expressed and released in a circadian manner by both hiMC and eosinophils in response to activation. Moreover, phosphorylation of ERK1/2, known to be involved in activation of hiMC and eosinophils, showed circadian rhythms in both cell types. Interestingly, all clock genes hPer1, hPer2, hCry1, hBmal1, and hClock were expressed in a similar circadian pattern in activated and unstimulated cells indicating that the local clock controls hiMC and eosinophils and subsequently allergic reactions but not vice versa.

Introduction

The circadian clock plays a key role in many physiological processes and behaviors such as in the maintenance and regulation of sleep–wake cycle, metabolism, or immunological processes (Reppert and Weaver, 2002). Interruption of circadian rhythms caused by sleep disturbances, jet lag or shiftwork resulted in biological and metabolic malfunction (De Bacquer et al., 2009), increased inflammation, emergence of malignant growth and cancer (Logan et al., 2012, Davis and Mirick, 2006, Filipski et al., 2003) as well as reduced life span.

The mammalian circadian clockwork system consists of a core oscillator located in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus and peripheral tissues (Froy and Chapnik, 2007, Reppert and Weaver, 2002). At the molecular level, generation of circadian rhythms is maintained by the expression of specific clock genes, and thus, the functional interaction of transcriptional and translational feedback loops. Briefly, the transcription factor circadian locomotor output cycles Kaput (CLOCK) forms a heterodimer with brain and muscle ARNT-like protein 1 (BMAL1) to activate the transcription of several genes, including Periods 13 (Per1, Per2, Per3) and Cryptochromes 12 (Cry1, Cry2) as well as clock controlled genes, upon binding to E-box containing (5′-CACGTG-3′) sequences. PER and CRY proteins oligomerize and migrate to the nucleus to act as transcription repressors resulting in the inhibition of CLOCK:BMAL1-mediated transcription (Reppert and Weaver, 2001).

The prevalence of allergic diseases, such as atopic dermatitis, asthma or allergic rhinitis has rapidly increased in the past decades especially in industrialized countries. The severity of major symptoms of allergic diseases as well as pulmonary function are frequently exacerbated between midnight and morning and exhibit a prominent 24 h variation (Smolensky et al., 2007, Durrington et al., 2014). These findings assume a role for the biological clock in allergic reactions and a novel approach of new therapeutic strategies and appropriate treatment within chronopharmacology.

Mast cells (MC) and eosinophils are known to be involved as major effector cells in type I allergic reactions, and in many other acute and chronic diseases (Minai-Fleminger and Levi-Schaffer, 2009, Bischoff, 2007). Within the allergic response, MC carry out their inflammatory effects by producing and releasing a variety of pre-stored (histamine, β-hexosaminidase or proteases) as well as de novo synthesized mediators, such as lipid mediators, proinflammatory cytokines and chemokines in response to activation via the high-affinity FcɛRI (Bischoff, 2007). Eosinophils are capable of producing the granule-stored proteins major basic protein (MBP), eosinophil peroxidase (EPO), eosinophil cationic protein (ECP), and eosinophil-derived neurotoxin/eosinophil protein X (EDN/EPX) as well as lipid mediators, growth factors, proinflammatory chemokines and cytokines (Kariyawasam and Robinson, 2006, Hogan et al., 2008).

A circadian variation of serum mast cell tryptase (Dugas-Breit et al., 2005) and plasma histamine (Friedman et al., 1989) concentrations with lower levels in the afternoon and nocturnal peaks has been reported. Several studies suggested that some eosinophil-specific mediators, including ECP, and EPX/EDN displayed a diurnal variation in sputum, urine and serum in patients with allergic rhinitis (Wolthers and Heuck, 2003). Recently, we demonstrated a functional circadian clock in human MC and eosinophils. Clock genes as well as mast cell-specific molecules, such as tryptase, FcɛRI α-chain and cKit were expressed in a circadian manner (Baumann et al., 2013). Similarly, an oscillatory expression pattern of the eosinophil-specific molecules ECP and EPX/EDN was observed in human eosinophils.

The aim of this study was to analyze the role of the molecular clock in the functionality of MC and eosinophils in response to activation and consequently, their relevance in allergic reactions.

Section snippets

Isolation and culture of human intestinal mast cells

Human intestinal mast cells (hiMC) were isolated from intestinal mucosa of macroscopically normal surgery specimens of patients who underwent bowel resection because of cancer. Intestinal tissue is a good source to obtain primary human MC. The procedure of combined mechanic and enzymatic tissue digestion is described in detail elsewhere (Sellge and Bischoff, 2006). The study has been approved by the local ethics committee. The obtained cell suspension was cultured overnight in medium RPMI 1640 + 

Clock genes oscillate in IgE-activated hiMC

We have recently demonstrated that MC isolated from intestinal tissue featured an intact molecular clock. All examined core clock genes, including hPer1, hPer2, hBmal1, hClock, and hCry1 were expressed and showed rhythmic oscillation in unstimulated hiMC (Baumann et al., 2013). Based on these findings, we set out to establish whether FcɛRI-mediated activation of hiMC influences the expression of clock genes. HiMC synchronized with dexamethasone were untreated or activated by FcɛRI crosslinking

Discussion

In this study, we observed that elementary components of the circadian clock reveal circadian expression in both unstimulated and activated human MC and eosinophils. Moreover, we could demonstrate that proinflammatory mediators such as the chemokines CXCL8 and CCL2 are expressed and secreted in a circadian fashion by hiMC and eosinophils in response to activation. These results emphasize an important role of the biological clock in allergic disorders. Indeed, allergic diseases such as allergic

Conflicts of interest

All authors declare that there are no conflicts of interest.

Acknowledgements

This work was supported by the Deutsche Forschungsgemeinschaft (LO 581/7-1 to Axel Lorentz and Oren Froy). The authors thank Yvonne Soltow for excellent technical assistance.

References (38)

  • A.C. Silver et al.

    Circadian expression of clock genes in mouse macrophages, dendritic cells, and B cells

    Brain Behav. Immun.

    (2012)
  • M.H. Smolensky et al.

    Chronobiology and chronotherapy of allergic rhinitis and bronchial asthma

    Adv. Drug Deliv. Rev.

    (2007)
  • X. Wang et al.

    A circadian clock in murine bone marrow-derived mast cells modulates IgE-dependent activation in vitro

    Brain Behav. Immun.

    (2011)
  • A. Baumann et al.

    The circadian clock is functional in eosinophils and mast cells

    Immunology

    (2013)
  • S.C. Bischoff

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

    Nat. Rev. Immunol.

    (2007)
  • T. Bollinger et al.

    Circadian clocks in mouse and human CD4+ T cells

    PLoS ONE

    (2011)
  • N. Cermakian et al.

    Crosstalk between the circadian clock circuitry and the immune system

    Chronobiol. Int.

    (2013)
  • S. Davis et al.

    Circadian disruption, shift work and the risk of cancer: a summary of the evidence and studies in Seattle

    Cancer Causes Control

    (2006)
  • D. De Bacquer et al.

    Rotating shift work and the metabolic syndrome: a prospective study

    Int. J. Epidemiol.

    (2009)
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