Histamine differentially regulates the production of Th1 and Th2 chemokines by keratinocytes through histamine H1 receptor

Effects of Histamine and the α-Tocopherol Metabolite α-13'-COOH in an Atopic Dermatitis Full-Thickness Skin Model

Atopic dermatitis is a T-cell mediated inflammatory skin disease with detected elevated levels of histamine in skin or plasma. In this study, the effects of histamine in a T_H2 cytokine environment on human keratinocytes and three-dimensional skin models were investigated. These models were used to explore the anti-inflammatory properties of the α-tocopherol-derived long-chain metabolite α-13'-carboxychromanol (α-13'-COOH). Histamine and T_H2 cytokine-induced proliferation of keratinocytes was studied using a scratch assay. The inflammatory marker interleukin-8 was significantly increased in healthy and T_H2 cytokine-stimulated keratinocytes and skin models after histamine treatment. The incubation of full-thickness skin models with T_H2 cytokines and histamine resulted in morphological changes in the epidermal layer, interpreted as hyperkeratosis. α-13'-COOH significantly decreased interleukin-8 in these disease-associated skin models. Histological staining of filaggrin showed skin-strengthening effects following α-13'-COOH treatment, without changes in mRNA expression. Cytokeratin 10 mRNA expression tended to be increased in response to α-13'-COOH. Anti-allergic properties of α-13'-COOH were studied by pre-incubation of human leukocytes with α-13'-COOH. This resulted in reduced sulfido-leukotriene synthesis. The hyperproliferation effect of histamine in atopic dermatitis skin models may be of further interest to the study of disease-associated morphological changes. Moreover, α-13'-COOH is a promising natural compound for the treatment of inflammatory skin diseases.

Effects of Cyclosporine A and Adalimumab on the expression profiles histaminergic system-associated genes and microRNAs regulating these genes in HaCaT cells

Previous studies have not completely elucidated the role of the histaminergic system in the pathogenesis of psoriasis. This study aimed to evaluate the effects of adalimumab and cyclosporine A on the expression of histaminergic system-related genes and miRNAs regulating these genes in bacterial lipopolysaccharide A (LPS)-stimulated human keratinocyte (HaCaT) cells. HaCaT cells were treated with 1 µg/mL LPS for 8 h, followed by treatment with 8 µg/mL adalimumab or 100 ng/mL cyclosporine A for 2, 8, or 24 h. Untreated cells served as controls. The cells were subjected to ribonucleic acid (RNA) extraction and microarray, quantitative real-time polymerase chain reaction, and enzyme-linked immunosorbent assay analyses. Statistical analysis was performed using the Statistica 13.0 PL (StatSoft, Cracow, Poland) and the Transcriptome Analysis Console programs (Affymetrix, Santa Clara, CA, USA) (p < 0.05). The differential expression of the following two miRNAs was not affected in LPS-stimulated cells upon treatment with cyclosporine A or adalimumab: hsa-miR-583 (downregulated expression), involved in the regulation of histamine receptor 1 - HRH1 (overexpression); has-miR-1275 (downregulated expression), involved in the regulation of histamine receptor 1 - HRH3 (overexpression) and Solute carrier family 22 member 3 - SLC23A2 (downregulated expression)). Adalimumab and cyclosporine A modulated the histaminergic system in HaCaT cells in vitro. However, further studies are needed to elucidate the underlying mechanisms.Abbreviations: (-) - downregulated in comparison to the control, (+) - overexpression in comparison to the control, ACTB - β-actine, ADA - Adenosine deaminase, ADCYAP1 - Adenylate Cyclase Activating Polypeptide 1, BMP - bone morphogenetic protein, bp - base pair, cAMP - adenosine 3' 5'-cyclic monophosphate, CBX7 - Chromobox protein homolog 7, cDNA - double-stranded complementary DNA, CSA - cyclosporine A DAG - diacylglycerol, DIAPH - Diaphanous related formin 1, DNMT - DNA methyltransferases, DRD2 - Dopamine receptor D2, EDN1 - Endothelin 1, EDNRA - Endothelin receptor type A, ELISA - Enzyme-linked immunosorbent assay, EZH2 - Enhancer of zeste homolog 2, FC - fold change, GABRB1 - Gamma-aminobutyric acid (GABA) A receptor, alpha 1, GABRB2 - Gamma-aminobutyric acid (GABA) A receptor, alpha 2, GABRB3 - Gamma-aminobutyric acid (GABA) A receptor, alpha 3, HaCaT - Human adult, low-calcium, high-temperature keratinocytes, HIS - Human Histamine, HLAs - human leukocyte antigens, HNMT - Histamine N-methyltransferase, HNMT - Histamine N-Methyltransferase, HRH1 - histamine receptor 1, HRH2 - histamine receptor 2, HRH3 - histamine receptor 3, HRH4 - histamine receptor 4, HTR6 - 5-Hydroxytryptamine Receptor 6, IGF1 - Insulin-like growth factor 1, IL10 -interleukin 10, IL12 -interleukin 12, IL6 - interleukin 6, IP3 - inositol 1,4,5-triphosphate, LPS - bacterial lipopolysaccharide A, LYN - LYN Proto-Oncogene, Src Family Tyrosine Kinase, MAPKs -mitogen-activated protein kinases, miRNA - micro RNA, MMP2 - matrix metalloproteinase-2, NHDF - Normal Human Dermal Fibroblasts, NHEK - Normal Human Epidermal Keratinocytes, OCT3 - organic cation transporter 3, PANTHER - Protein ANalysis THrough Evolutionary Relationships Classification, PBS - phosphate-buffered saline, PI3K-AKT - phosphatidylinositol 3-kinase-protein kinase B, PIP2 - phosphatidylinositol 4,5 bisphosphate, PMSF - phenylmethylsulfonyl fluoride, PSORS1- psoriasis susceptibility gene 1, qRT-PCR - quantitative Reverse Transcription Polymerase Chain Reaction, RNA - ribonucleic acid, RNAi - RNA interference, RTqPCR - Real-Time Quantitative Reverse Transcription Reaction, SLC223A2 - Solute carrier family 22 member 3, SNX -Sorting nexin, SOX9 - SRY-Box Transcription Factor 9, TGF-α - transforming growth factor α, TGF-β - transforming growth factor beta, TNF-α - tumor necrosis factor alpha, TP53 - tumor protein 5 z, VAMP2 - Vesicle associated membrane protein 2.

Corticosteroid reduction by addition of cetirizine and montelukast in biopsy-proven minimal-change nephrotic syndrome concomitant with allergic disorders

Recent reports suggest helper T-cell abnormalities in minimal-change nephrotic syndrome (MCNS), which often complicate allergic disorders that show a similar helper T-cell profile with Th2/Th17 predominance. However, the effect of anti-allergy therapy on MCNS remains unknown. This retrospective study included 51 patients with biopsy-proven MCNS recruited between November 2012 and October 2015, with follow-up through November 2017. We analyzed relapse and temporal daily corticosteroid dose with and without co-administration of histamine H1 receptor antagonist, cetirizine, and cysteinyl-leukotriene receptor antagonist, montelukast, as well as between baseline and after follow-up. Thirteen patients were treated with cetirizine and montelukast in addition to conventional therapy, whereas 38 patients were treated by conventional therapy only, consisting of corticosteroids and immunosuppressants. To adjust for baseline clinical characteristics, a 1:1 propensity score–matched model was applied. The clinical characteristics of the two groups after matching were similar at baseline. The treatment group showed a significant reduction in the lowest daily dose of oral prednisolone throughout the entire treatment course after the study compared to that of baseline (p < 0.025), which was not observed in the control group (p = 0.37), and showed significantly higher percentage of patients establishing corticosteroid-free state for the first time throughout the entire treatment course by addition of cetirizine and montelukast compared to the control group (p < 0.025). The study shows, for the first time, the steroid sparing effect of cetirizine and montelukast in addition to conventional treatment in MCNS patients with concomitant allergies.

ALDH enzyme activity is regulated by Nodal and histamine in the A549 cell line

The present study aimed to examine whether the enzyme activity of aldehyde dehydrogenase (ALDH) was regulated by Nodal and histamine in the human alveolar adenocarcinoma A549 cell line. The regulated enzyme activity of ALDH was analyzed by flow cytometry in the A549 cell line. ALDH1 and Nodal expression was investigated by immunohistochemistry in28 cases of lung mixed adenocarcinoma. The enzyme activity of ALDH was upregulated by histamine and agonists of histamine H1 receptor (H1R) and histamine H2 receptor (H2R). ALDH activity was also downregulated by recombinant human Nodal and antagonists of H1R and H2R in the A549 cell line. In addition, expression of Nodal and ALDH1 were inversely correlated in lung mixed adenocarcinoma. ALDH enzyme activity was regulated by Nodal and histamine in lung adenocarcinoma.

Expression and function of histamine and its receptors in atopic dermatitis

Background

Atopic dermatitis constitutes a most burdensome chronic inflammatory skin disease. Standard treatment is cumbersome and often targets its main symptom, pruritus, only insufficiently.

Findings

Recent advances in our understanding of the role of histamine and its four receptors suggest new approaches which target the histamine receptors alone or as combination therapies to more efficiently combat pruritus and inflammation in atopic dermatitis.

Conclusions

With this review, we provide an overview on histamine and the expression of its four receptors on skin resident and nonresident cells. Furthermore, we summarize recent studies which suggest anti-histamine therapy to efficiently combat pruritus and inflammation in atopic dermatitis and discuss possible approaches to incorporate these findings into more effective treatment strategies for atopic dermatitis in childhood.

c-kit plays a critical role in induction of intravenous tolerance in experimental autoimmune encephalomyelitis

c-kit (CD117) is a tyrosine kinase receptor found in various types of immune cells. It has been shown that c-kit plays a role in the pathogenesis of multiple sclerosis, an inflammatory demyelinating disorder of the CNS. Recent data have suggested an immunoregulatory effect of c-kit. We therefore examined the role of c-kit in autoantigen-induced i.v. tolerance in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. Our results show that induction of intravenous tolerance against EAE in B6 mice is characterized by increased numbers of CD117(+) cells and altered mast cell-associated molecules in the periphery and in the CNS. W(-sh) (c-kit-deficient) mice were resistant to i.v autoantigen-induced tolerance, with increased proinflammatory cytokine production in the periphery. I.v. autoantigen in WT mice suppressed the production of proinflammatory cytokines IFN-γ and IL-6 and up-regulated the expression of FoxP3, a transcription factor of Tregs; however, in W(-sh) mice, IFN-γ and IL-6 were increased with a failure of FoxP3 induction upon i.v. autoantigen injection and is thus a mechanism for resistance to i.v. tolerance induction in these mice. We conclude that c-kit signaling has a regulatory role in i.v. tolerance and could be a target for potential immunotherapy in autoimmune disorders.

Effects of histamine and its antagonists on murine T-cells and bone marrow-derived dendritic cells

We determined the effects of histamine and its antagonists on the surface marker expression of dendritic cells (DCs) and the influence of lipopolysaccharide (LPS), histamine, and histamine receptor antagonists on DCs and T-cells. The bone marrow was extracted from the femurs and tibiae of 6- to 8-week-old female Balb/c mice and cultured in medium containing penicillin, streptomycin, L-glutamine, fetal calf serum, or granulocyte macrophage colony-stimulating factor (GM-CSF) alone or with interleukin (IL)-4. The cells received three different doses of LPS and histamine, plus three different doses of descarboethoxyloratadine (DCL). We assayed the supernatant for various cytokines. The spleen cells of DO11.10 mice were examined by flow cytometry, which included labeling and sorting CD4+ T-cells, as well as coculture of DCs and T-cells with ovalbumin (OVA)_323–339 peptide. Histamine or histamine plus DCL did not affect the expression of major histocompatibility complex class II, CD11c, CD11b, CD86, and CD80. However, GM-CSF increased the expression of all markers except CD80. Histamine increased interferon-γ production in GM-CSF + IL-4-cultured cells; it also enhanced IL-10 production, but suppressed IL-12 production in LPS-stimulated DCs with no DCL. Cimetidine inhibited IL-10 production and restored IL-12 secretion in LPS-treated DCs. LPS increased IL-10 and decreased IL-12 levels. GM-CSF + IL-4-generated DCs had a stronger stimulatory effect on DO11.10 T-cell proliferation than GM-CSF-generated DCs. Inducible costimulator ligand expression was higher in GM-CSF + IL-4- than in GM-CSF-generated DC groups after 2 days of coculture, but decreased 4 days later. IL-13 production was higher in bone marrow DCs generated with GM-CSF than in those generated with GM-CSF + IL-4. OVA-pulsed DCs and OVA-plus-DCL DCs showed increased IL-12 levels. OVA plus LPS increased both IL-10 and interferon-α. Although histamine or histamine receptor-1 antagonists did not influence DC LPS-driven maturation, they influenced cytokine production. LPS and GM-CSF influenced surface marker expression and cytokine production.

Regulation of the immune response and inflammation by histamine and histamine receptors

Histamine is a biogenic amine with extensive effects on many cell types, including important immunologic cells, such as antigen-presenting cells, natural killer cells, epithelial cells, and T and B lymphocytes. Histamine and its 4 receptors represent a complex system of immunoregulation with distinct effects dependent on receptor subtypes and their differential expression. These are influenced by the stage of cell differentiation, as well as microenvironmental influences, leading to the selective recruitment of effector cells into tissue sites accompanied by effects on cellular maturation, activation, polarization, and effector functions, which lead to tolerogenic or proinflammatory responses. In this review we discuss the regulation of histamine secretion, receptor expression, and differential activation of cells within both the innate and adaptive immune responses. It is clear that the effects of histamine on immune homeostasis are dependent on the expression and activity of the 4 currently known histamine receptors, and we also recognize that 100 years after the original identification of this biogenic amine, we still do not fully understand the complex regulatory interactions between histamine and the host immune response to everyday microbial and environmental challenges.