Defective angiogenesis in the inflammatory granulation tissue in histidine decarboxylase-deficient mice but not in mast cell-deficient mice

H2 antihistamines: May be useful for combination therapies in cancer?

Cancer morbimortality is still a great concern despite advances in research and therapies. Histamine and its receptors' ligands can modulate different biological responses according to the cell type and the receptor subtype involved. Besides the wide variety of histamine functions in normal tissues, diverse roles in the acquisition of hallmarks of cancer such as sustained proliferative signaling, resistance to cell death, angiogenesis, metastasis, altered immunity and modified microenvironment have been described. This review summarizes the present knowledge of the various roles of histamine H2 receptor (H2R) ligands in neoplasias. A bioinformatic analysis of human tumors showed dissimilar results in the expression of the H2R gene according to tumor type when comparing malignant versus normal tissues. As well, the relationship between patients' survival parameters and H2R gene expression levels also varied, signaling important divergences in the role of H2R in neoplastic progression in different cancer types. Revised experimental evidence showed multiple effects of H2R antihistamines on several of the cited hallmarks of cancer. Interventional and retrospective clinical studies evaluated different H2R antihistamines in cancer patients with two main adjuvant uses: improving antitumor efficacy (which includes regulation of immune response) and preventing toxic adverse effects produced by chemo or radiotherapy. While there is a long path to go, research on H2R antihistamines may provide new opportunities for developing more refined combination therapeutic strategies for certain cancer types to improve patients' survival and health-related quality of life.

Impact of Prevascularization on Immunological Environment and Early Engraftment in Subcutaneous Islet Transplantation

BACKGROUND

The utilization of islet-like cells derived from pluripotent stem cells may resolve the scarcity of islet transplantation donors. The subcutaneous space is a promising transplantation site because of its capacity for graft observation and removal, thereby ensuring safety. To guarantee subcutaneous islet transplantation, physicians should ensure ample blood supply. Numerous methodologies, including prevascularization, have been investigated to augment blood flow, but the optimal approach remains undetermined.

METHODS

From C57BL/6 mice, 500 syngeneic islets were transplanted into the prevascularized subcutaneous site of recipient mice by implanting agarose rods with basic fibroblast growth factor at 1 and 2 wk. Before transplantation, the blood glucose levels, cell infiltration, and cytokine levels at the transplant site were evaluated. Furthermore, we examined the impact of the extracellular matrix capsule on graft function and the inflammatory response.

RESULTS

Compared with the 1-wk group, the 2-wk group exhibited improved glycemic control, indicating that longer prevascularization enhanced transplant success. Flow cytometry analysis detected immune cells, such as neutrophils and macrophages, in the extracellular matrix capsules, whereas cytometric bead array analysis indicated the release of inflammatory and proinflammatory cytokines. Treatment with antitumor necrosis factor and anti-interleukin-6R antibodies in the 1-wk group improved graft survival, similar to the 2-wk group.

CONCLUSIONS

In early prevascularization before subcutaneous transplantation, neutrophil and macrophage accumulation prevented early engraftment owing to inflammatory cytokine production.

Serum Metabolic Fingerprints Characterize Systemic Lupus Erythematosus

Metabolic fingerprints in serum characterize diverse diseases for diagnostics and biomarker discovery. The identification of systemic lupus erythematosus (SLE) by serum metabolic fingerprints (SMFs) will facilitate precision medicine in SLE in an early and designed manner. Here, a discovery cohort of 731 individuals including 357 SLE patients and 374 healthy controls (HCs), and a validation cohort of 184 individuals (SLE/HC, 91/93) are constructed. Each SMF is directly recorded by nano-assisted laser desorption/ionization mass spectrometry (LDI MS) within 1 minute using 1 µL of native serum, which contains 908 mass to charge features. Sparse learning of SMFs achieves the SLE identification with sensitivity/specificity and area-under-the-curve (AUC) up to 86.0%/92.0% and 0.950 for the discovery cohort. For the independent validation cohort, it exhibits no performance loss by affording the sensitivity/specificity and AUC of 89.0%/100.0% and 0.992. Notably, a metabolic biomarker panel is screened out from the SMFs, demonstrating the unique metabolic pattern of SLE patients different from both HCs and rheumatoid arthritis patients. In conclusion, SMFs characterize SLE by revealing its unique metabolic pattern. Different regulation of small molecule metabolites contributes to the precise diagnosis of autoimmune disease and further exploration of the pathogenic mechanisms.

Histidine decarboxylase inhibitors: a novel therapeutic option for the treatment of leydigioma

Recent reports indicate an increase in Leydig cell tumor (LCT) incidence. Radical orchiectomy is the standard therapy in children and adults, although it entails physical and psychosocial side effects. Testis-sparing surgery can be a consideration for benign LCT of 2.5 cm or less in size. Malignant LCTs respond poorly to conventional chemotherapy, so new treatment modalities are needed. In this study, we observed increased histidine decarboxylase expression and pro-angiogenic potential in LCT surgically resected from pediatric patients (fetal to pubertal) vs control samples from patients without endocrine or metabolic disorders which were collected at necropsy. We, therefore, evaluated for the first time the antitumor efficacy of two histidine decarboxylase inhibitors (α-methyl-dl-histidine dihydrochloride (α-MHD) and epigallocatechin gallate (EGCG)), alone and combined with carboplatin, in two preclinical models of LCT. MA-10 and R2C Leydig tumor cells, representing two different LCT subtypes, were used to generate syngeneic and xenograft mouse LCT models, respectively. In the syngeneic model, monotherapy with α-MHD effectively reduced tumor growth and angiogenesis. In the xenografts, which showed co-expression of histidine decarboxylase and CYP19, the combination of EGCG plus carboplatin was the most effective therapy, leading to LCT growth arrest and undetectable levels of plasmatic estradiol. Testicular and body weights remained unaltered. On the basis of this study, histidine decarboxylase may emerge as a novel pharmacological target for LCT treatment.

P311 Facilitates the Angiogenesis and Wound Healing Function of MSCs by Increasing VEGF Production

As a potential clinical therapeutic cell for injured tissue repair, mesenchymal stem cells (MSCs) have attracted increasing attention. Enhancing the pro-healing function of MSCs has gradually become an essential topic in improving the clinical efficacy of MSCs. Recently, studies have shown that neuronal protein 3.1 (P311) plays a crucial role in promoting skin wound healing, suggesting P311 gene modification may improve the pro-healing function of MSCs. In this study, we demonstrated that increasing the in vivo expression of P311 could significantly enhance the ability of MSCs to lessen the number of inflammatory cells, increase the expression of IL10, reduce the levels of TNF-α and IFN-γ, increase collagen deposition, promote angiogenesis, and ultimately accelerate skin wound closure and improve the quality of wound healing. Importantly, we uncovered that P311 enhanced the pro-angiogenesis function of MSCs by increasing the production of vascular endothelial growth factor (VEGF) in vitro and in vivo. Mechanistically, we revealed that the mTOR signalling pathway was closely related to the regulation of P311 on VEGF production in MSCs. Together, our data displayed that P311 gene modification in MSCs augments their capabilities to promote skin wound closure, which might bring the dawn for its clinical application in the future.

Pathophysiological Roles of Histamine Receptors in Cancer Progression: Implications and Perspectives as Potential Molecular Targets

High levels of histamine and histamine receptors (HRs), including H1R~H4R, are found in many different types of tumor cells and cells in the tumor microenvironment, suggesting their involvement in tumor progression. This review summarizes the latest evidence demonstrating the pathophysiological roles of histamine and its cognate receptors in cancer biology. We also discuss the novel therapeutic approaches of selective HR ligands and their potential prognostic values in cancer treatment. Briefly, histamine is highly implicated in cancer development, growth, and metastasis through interactions with distinct HRs. It also regulates the infiltration of immune cells into the tumor sites, exerting an immunomodulatory function. Moreover, the effects of various HR ligands, including H1R antagonists, H2R antagonists, and H4R agonists, on tumor progression in many different cancer types are described. Interestingly, the expression levels of HR subtypes may serve as prognostic biomarkers in several cancers. Taken together, HRs are promising targets for cancer treatment, and HR ligands may offer novel therapeutic potential, alone or in combination with conventional therapy. However, due to the complexity of the pathophysiological roles of histamine and HRs in cancer biology, further studies are warranted before HR ligands can be introduced into clinical settings.

Mast Cells and Skin and Breast Cancers: A Complicated and Microenvironment-Dependent Role

Mast cells are important sentinel cells in host defense against infection and major effector cells in allergic disease. The role of these cells in cancer settings has been widely debated. The diverse range of mast cell functions in both immunity and tissue remodeling events, such as angiogenesis, provides multiple opportunities for mast cells to modify the tumor microenvironment. In this review, we consider both skin and breast cancer settings to address the controversy surrounding the importance of mast cells in the host response to tumors. We specifically address the key mediators produced by mast cells which impact tumor development. The role of environmental challenges in modifying mast cell responses and opportunities to modify mast cell responses to enhance anti-tumor immunity are also considered. While the mast cell's role in many cancer contexts is complicated and poorly understood, the activities of these tissue resident and radioresistant cells can provide important opportunities to enhance anti-cancer responses and limit cancer development.

Expression of Histidine Decarboxylase and Its Roles in Inflammation

Histamine is a well-known mediator of inflammation that is released from mast cells and basophils. To date, many studies using histamine receptor antagonists have shown that histamine acts through four types of receptors: H1, H2, H3, and H4. Thus, histamine plays more roles in various diseases than had been predicted. However, our knowledge about histamine-producing cells and the molecular mechanisms underlying histamine production at inflammatory sites is still incomplete. The histamine producing enzyme, histidine decarboxylase (HDC), is commonly induced at inflammatory sites during the late and chronic phases of both allergic and non-allergic inflammation. Thus, histamine levels in tissues are maintained at effective concentrations for hours, enabling the regulation of various functions through the production of cytokines/chemokines/growth factors. Understanding the regulation of histamine production will allow the development of a new strategy of using histamine antagonists to treat inflammatory diseases.

Genetic and Imaging Approaches Reveal Pro-Inflammatory and Immunoregulatory Roles of Mast Cells in Contact Hypersensitivity

Contact hypersensitivity (CHS) is a common T cell-mediated skin disease induced by epicutaneous sensitization to haptens. Mast cells (MCs) are widely deployed in the skin and can be activated during CHS responses to secrete diverse products, including some with pro-inflammatory and anti-inflammatory functions. Conflicting results have been obtained regarding pathogenic versus protective roles of MCs in CHS, and this has been attributed in part to the limitations of certain models for studying MC functions in vivo. This review discusses recent advances in the development and analysis of mouse models to investigate the roles of MCs and MC-associated products in vivo. Notably, fluorescent avidin-based two-photon imaging approaches enable in vivo selective labeling and simultaneous tracking of MC secretory granules (e.g., during MC degranulation) and MC gene activation by real-time longitudinal intravital microscopy in living mice. The combination of such genetic and imaging tools has shed new light on the controversial role played by MCs in mouse models of CHS. On the one hand, they can amplify CHS responses of mild severity while, on the other hand, can limit the inflammation and tissue injury associated with more severe or chronic models, in part by representing an initial source of the anti-inflammatory cytokine IL-10.

Inflammation in sickle cell disease

The primary β-globin gene mutation that causes sickle cell disease (SCD) has significant pathophysiological consequences that result in hemolytic events and the induction of the inflammatory processes that ultimately lead to vaso-occlusion. In addition to their role in the initiation of the acute painful vaso-occlusive episodes that are characteristic of SCD, inflammatory processes are also key components of many of the complications of the disease including autosplenectomy, acute chest syndrome, pulmonary hypertension, leg ulcers, nephropathy and stroke. We, herein, discuss the events that trigger inflammation in the disease, as well as the mechanisms, inflammatory molecules and cells that propagate these inflammatory processes. Given the central role that inflammation plays in SCD pathophysiology, many of the therapeutic approaches currently under pre-clinical and clinical development for the treatment of SCD endeavor to counter aspects or specific molecules of these inflammatory processes and it is possible that, in the future, we will see anti-inflammatory drugs being used either together with, or in place of, hydroxyurea in those SCD patients for whom hematopoietic stem cell transplants and evolving gene therapies are not a viable option.

Bile duct ligation-induced biliary hyperplasia, hepatic injury, and fibrosis are reduced in mast cell-deficient KitW-sh mice

Activated mast cells (MCs) release histamine (HA) and MCs infiltrate the liver following bile duct ligation (BDL), increasing intrahepatic bile duct mass (IBDM) and fibrosis. We evaluated the effects of BDL in MC-deficient (Kit^W-sh ) mice. Wild-type (WT) and Kit^W-sh mice were subjected to sham or BDL for up to 7 days and Kit^W-sh mice were injected with cultured mast cells or 1× phosphate-buffered saline (PBS) before collecting serum, liver, and cholangiocytes. Liver damage was assessed by hematoxylin and eosin and alanine aminotransferase levels. IBDM was detected by cytokeratin-19 expression and proliferation by Ki-67 immunohistochemistry (IHC). Fibrosis was detected by IHC, hydroxyproline content, and by qPCR for fibrotic markers. Hepatic stellate cell (HSC) activation and transforming growth factor-beta 1 (TGF-β1) expression/secretion were evaluated. Histidine decarboxylase (HDC) and histamine receptor (HR) expression were detected by qPCR and HA secretion by enzymatic immunoassay. To evaluate vascular cells, von Willebrand factor (vWF) and vascular endothelial growth factor (VEGF)-C expression were measured. In vitro, cultured HSCs were stimulated with cholangiocyte supernatants and alpha-smooth muscle actin levels were measured. BDL-induced liver damage was reduced in BDL Kit^W-sh mice, whereas injection of MCs did not mimic BDL-induced damage. In BDL Kit^W-sh mice, IBDM, proliferation, HSC activation/fibrosis, and TGF-β1 expression/secretion were decreased. The HDC/HA/HR axis was ablated in sham and BDL Kit^W-sh mice. vWF and VEGF-C expression decreased in BDL Kit^W-sh mice. In Kit^W-sh mice injected with MCs, IBDM, proliferation, fibrosis, and vascular cell activation increased. Stimulation with cholangiocyte supernatants from BDL WT or Kit^W-sh mice injected with MCs increased HSC activation, which decreased with supernatants from BDL Kit^W-sh mice.

CONCLUSION

MCs promote hyperplasia, fibrosis, and vascular cell activation. Knockout of MCs decreases BDL-induced damage. Modulation of MCs may be important in developing therapeutics for cholangiopathies. (Hepatology 2017;65:1991-2004).

Induced histamine regulates Ni elution from an implanted Ni wire in mice by downregulating neutrophil migration

Histamine regulates various inflammatory reactions. We have reported that the expression of histidine decarboxylase (HDC) was induced by subcutaneous implantation of nickel (Ni) wire. However, the source and functions of histamine in Ni elution and Ni wire-induced inflammation have not been completely studied. We aimed to elucidate the effects of de novo synthesized histamine on leucocyte infiltration and Ni elution. Implantation of Ni wire induced an increase in the Ni ion content of the surrounding tissues and serum and in the mRNA levels of HDC, a histamine-producing enzyme, macrophage inflammatory protein-2 (MIP-2), a chemoattractant for neutrophils, and monocyte chemoattractant protein-1 (MCP-1), a chemoattractant for monocytes. The Ni wire induced HDC expression even in mast cell-deficient WBB6F1-W/W^V mice. In HDC knockout (HDC KO) mice, the Ni wire-induced increase in MIP-2 mRNA expression was significantly higher than that in wild-type mice but not MCP-1. MIP-2 expression was enhanced in histamine H2 receptor knockout (H2R KO) mice but not in WBB6F1-W/W^V mice. Histamine inhibited NiCl₂ -induced MIP-2 mRNA expression in mouse bone marrow-derived macrophages (BMDMs) obtained from wild-type mice; this inhibition was not observed in BMDMs from H2R KO mice. Ni elution increased in HDC KO mice, in which leucocyte infiltration also increased, and was suppressed in mice treated with neutrophil-specific antibody. These results suggest that the Ni wire induced HDC expression in non-mast cells and that, in the chronic phase of inflammation, endogenous histamine reduced Ni elution, probably through regulation of MIP-2 expression and neutrophil migration.

Utilizing the Foreign Body Response to Grow Tissue Engineered Blood Vessels in Vivo

It is well known that the number of patients requiring a vascular grafts for use as vessel replacement in cardiovascular diseases, or as vascular access site for hemodialysis is ever increasing. The development of tissue engineered blood vessels (TEBV's) is a promising method to meet this increasing demand vascular grafts, without having to rely on poorly performing synthetic options such as polytetrafluoroethylene (PTFE) or Dacron. The generation of in vivo TEBV's involves utilizing the host reaction to an implanted biomaterial for the generation of completely autologous tissues. Essentially this approach to the development of TEBV's makes use of the foreign body response to biomaterials for the construction of the entire vascular replacement tissue within the patient's own body. In this review we will discuss the method of developing in vivo TEBV's, and debate the approaches of several research groups that have implemented this method.

Study of early stage non-small-cell lung cancer using Orbitrap-based global serum metabolomics

Purpose

The aim of the project was to apply ultra-high-performance liquid chromatography–quadrupole-Orbitrap-high-resolution mass spectrometry for serum metabolite profiling of non-small-cell lung cancer (NSCLC). This Orbitrap-based methodology has been applied for a study of NSCLC potential markers for the first time.

Methods

After extraction using protein precipitation, sera were separated on the ACE Excel 2 C18-PFP (100 × 2.1 mm, 2.0 µm) column using gradient elution and analyzed within the range of 70–1000 m/z. Only patients with early stage disease (stages IA–IIB) were included in the study, providing opportunity to find biomarkers for early lung cancer detection. The resulting metabolite profiles were subjected to univariate and multivariate statistical tests.

Results

36 features were found significantly changed between NSCLC group and controls after FDR adjustment and 19 were identified using various metabolite databases (in-house library, HMDB, mzCloud). The study revealed a number of NSCLC biomarker candidates which belong to such compound classes as acylcarnitines, organic acids, and amino acids. Multivariate ROC curve built using 12 identified metabolites was characterized by AUC = 0.836 (0.722–0.946). There were no significant differences in the serum metabolite profiles between two most common histological types of lung cancer—adenocarcinoma and squamous cell carcinoma.

Conclusions

Through identification of novel potential tumor markers, Orbitrap-based global metabolic profiling is a useful strategy in cancer research. Our study can accelerate development of new diagnostic and therapeutic strategies in NSCLC. The metabolites involved in discrimination between NSCLC patients and the control subjects should be further explored using a targeted approach.

Electronic supplementary material

The online version of this article (doi:10.1007/s00432-017-2347-0) contains supplementary material, which is available to authorized users.

Effects of salbutamol on the inflammatory parameters and angiogenesis in the rat air pouch model of inflammation

In the present study, effects of salbutamol on the inflammatory parameters, angiogenesis, interleukin-1 beta (IL-1β) and vascular endothelial growth factor (VEGF) levels were investigated in an air pouch model of inflammation. Inflammation was induced by intrapouch administration of 1% solution of sterile carrageenan in male Wistar rats. Salbutamol (125, 250 and 500 µg/rat) and salbutamol (500 µg/rat) plus propranolol (100 μg/rat) were injected intrapouch. After 6 and 72 h, fluid inside the pouches was collected to measure volume of exudates, leukocytes number and IL-1β levels. To determine angiogenesis, the granulation tissues were dissected out and weighed 3 days after carrageenan injection, then hemoglobin concentration was assessed using a hemoglobin assay kit. In addition, amount of VEGF in the exudates was measured 72 h after induction of inflammation. Leukocyte accumulation and the volume of exudates were significantly inhibited by salbutamol administration. In addition, salbutamol decreased the production of VEGF and IL-1β. Moreover, all used doses of salbutamol significantly inhibited angiogenesis. Interestingly, effects of salbutamol on the attenuation of angiogenesis and inflammatory parameters was similar to diclofenac sodium. Co-administration of propranolol with salbutamol clearly reversed anti-inflammatory effects of salbutamol. Salbutamol can decrease acute and chronic inflammation by β₂-adrenergic receptors activation. The observed IL-1β and VEGF inhibitory properties of salbutamol may be responsible for anti-inflammatory and anti-angiogenic effect of the agent.

Regulation of the Cardiovascular System by Histamine

Histamine mediates a wide range of cellular responses, including allergic and inflammatory reactions, gastric acid secretion, and neurotransmission in the central nervous system. Histamine also exerts a series of actions upon the cardiovascular system but may not normally play a significant role in regulating cardiovascular function. During tissue injury, inflammation, and allergic responses, mast cells (or non-mast cells) within the tissues can release large amounts of histamine that leads to noticeable cardiovascular effects. Owing to intensive research during several decades, the distribution, function, and pathophysiological role of cardiovascular H₁- and H₂-receptors has become recognized adequately. Besides the recognized H₁- and H₂-receptor-mediated cardiovascular responses, novel roles of H₃- and H₄-receptors in cardiovascular physiology and pathophysiology have been identified over the last decade. In this review, we describe recent advances in our understanding of cardiovascular function and dysfunction mediated by histamine receptors, including H₃- and H₄-receptors, their potential mechanisms of action, and their pathological significance.

Differential function and regulation of orphan nuclear receptor TR3 isoforms in endothelial cells

TR3 has been reported to be an excellent target for angiogenesis therapies. We reported three TR3 transcript variant messenger RNAs (mRNAs) are expressed in human umbilical vein endothelial cell (HUVEC) and are differentially regulated by vascular endothelial growth factor (VEGF). TR3 transcript variant 1 (TR3-TV1) and variant 2 (TR3-TV2) encoding the same TR3 isoform 1 protein (TR3-iso1) that was named TR3 has been extensively studied. However, the function of TR3 isoform 2 protein (TR3-iso2) encoded by TR3 transcript variant 3 (TR3-TV3) is still not known. Here, we clone and express the novel TR3-iso2 protein and find that expression of TR3-iso2, in contrast to TR3-iso1, inhibits endothelial cell proliferation induced by VEGF-A, histamine, and phorbol-12-myristate-13-acetate (PMA). The differential function of TR3-iso2 correlates with the down-regulation of cyclin D1. However, TR3-iso2 plays similar roles in endothelial cell migration and monolayer permeability as TR3-iso1. We further demonstrate that several intracellular signaling pathways are involved in histamine-induced TR3 transcript variants, including histamine receptor H1-mediated phospholipase C (PLC)/calcium /calcineurin/protein kinase C (PKC)/protein kinase D (PKD) pathway and ERK pathway, as well as histamine receptor H3-mediated PKC-ERK pathway. Further, expressions of TR3-TV1, TR3-TV2, and TR3-TV3 by VEGF and histamine are regulated by different promoters, but not by their mRNA stability.

Potential effector and immunoregulatory functions of mast cells in mucosal immunity

Mast cells (MCs) are cells of hematopoietic origin that normally reside in mucosal tissues, often near epithelial cells, glands, smooth muscle cells, and nerves. Best known for their contributions to pathology during IgE-associated disorders such as food allergy, asthma, and anaphylaxis, MCs are also thought to mediate IgE-associated effector functions during certain parasite infections. However, various MC populations also can be activated to express functional programs--such as secreting preformed and/or newly synthesized biologically active products--in response to encounters with products derived from diverse pathogens, other host cells (including leukocytes and structural cells), damaged tissue, or the activation of the complement or coagulation systems, as well as by signals derived from the external environment (including animal toxins, plant products, and physical agents). In this review, we will discuss evidence suggesting that MCs can perform diverse effector and immunoregulatory roles that contribute to homeostasis or pathology in mucosal tissues.

Methanolic Extract of Ficus carica Linn. Leaves Exerts Antiangiogenesis Effects Based on the Rat Air Pouch Model of Inflammation

The antiangiogenesis effect of Ficus carica leaves extract in an air pouch model of inflammation was investigated in rat. Inflammation was induced by injection of carrageenan into pouches. After antioxidant capacity and total phenolic content (TPC) investigations, the extract was administered at 5, 25, and 50 mg/pouch, and then the volume of exudates, the cell number, TNFα, PGE₂, and VEGF levels were measured. Angiogenesis of granulation tissues was determined by measuring hemoglobin content. Based on the DPPH assay, the extract had significant antioxidant activity with TPC of 11.70 mg GAE/100 g dry sample. In addition, leukocyte accumulation and volume of exudate were significantly inhibited by the extract. Moreover, it significantly decreased the production of TNFα, PGE₂, and VEGF, while angiogenesis was significantly inhibited by all administered doses. Interestingly, attenuation of angiogenesis and inflammatory parameters (except leukocyte accumulation) by the extract was similar to that shown by diclofenac. The extract has anti-inflammatory effects and ameliorated cell influx and exudation to the site of the inflammatory response which may be related to the local inhibition of TNFα, PGE₂, and VEGF levels as similarly shown by diclofenac. The antiangiogenesis and anti-VEGF effects of Ficus carica may be correlated with its significant antioxidant potentials.

Knockout of histidine decarboxylase decreases bile duct ligation-induced biliary hyperplasia via downregulation of the histidine decarboxylase/VEGF axis through PKA-ERK1/2 signaling

Histidine is converted to histamine by histidine decarboxylase (HDC). We have shown that cholangiocytes 1) express HDC, 2) secrete histamine, and 3) proliferate after histamine treatment via ERK1/2 signaling. In bile duct-ligated (BDL) rodents, there is enhanced biliary hyperplasia, HDC expression, and histamine secretion. This studied aimed to demonstrate that knockdown of HDC inhibits biliary proliferation via downregulation of PKA/ERK1/2 signaling. HDC(-/-) mice and matching wild-type (WT) were subjected to sham or BDL. After 1 wk, serum, liver blocks, and cholangiocytes were collected. Immunohistochemistry was performed for 1) hematoxylin and eosin, 2) intrahepatic bile duct mass (IBDM) by cytokeratin-19, and 3) HDC biliary expression. We measured serum and cholangiocyte histamine levels by enzyme immunoassay. In total liver or cholangiocytes, we studied: 1) HDC and VEGF/HIF-1α expression and 2) PCNA and PKA/ERK1/2 protein expression. In vitro, cholangiocytes were stably transfected with shRNA-HDC plasmids (or control). After transfection we evaluated pPKA, pERK1/2, and cholangiocyte proliferation by immunoblots and MTT assay. In BDL HDC(-/-) mice, there was decreased IBDM, PCNA, VEGF, and HDC expression compared with BDL WT mice. Histamine levels were decreased in BDL HDC(-/-). BDL HDC(-/-) livers were void of necrosis and inflammation compared with BDL WT. PKA/ERK1/2 protein expression (increased in WT BDL) was lower in BDL HDC(-/-) cholangiocytes. In vitro, knockdown of HDC decreased proliferation and protein expression of PKA/ERK1/2 compared with control. In conclusion, loss of HDC decreases BDL-induced biliary mass and VEGF/HIF-1α expression via PKA/ERK1/2 signaling. Our data suggest that HDC is a key regulator of biliary proliferation.

Ethyl-p-methoxycinnamate isolated from Kaempferia galanga inhibits inflammation by suppressing interleukin-1, tumor necrosis factor-α, and angiogenesis by blocking endothelial functions

OBJECTIVE

The present study aimed to investigate the mechanisms underlying the anti-inflammatory and anti-angiogenic effects of ethyl-p-methoxycinnamate isolated from Kaempferia galanga.

METHODS

The anti-inflammatory effects of ethyl-p-methoxycinnamate were assessed using the cotton pellet granuloma assay in rats, whereby the levels of interleukin-1 and tumor necrosis factor-α were measured in the animals' blood. In addition, the levels of interleukin, tumor necrosis factor, and nitric oxide were measured in vitro using the human macrophage cell line (U937). The analgesic effects of ethyl-p-methoxycinnamate were assessed by the tail flick assay in rats. The anti-angiogenic effects were evaluated first by the rat aortic ring assay and, subsequently, by assessing the inhibitory effects of ethyl-p-methoxycinnamate on vascular endothelial growth factor, proliferation, migration, and tube formation in human umbilical vein endothelial cells.

RESULTS

Ethyl-p-methoxycinnamate strongly inhibited granuloma tissue formation in rats. It prolonged the tail flick time in rats by more than two-fold compared with the control animals. The inhibition of interleukin and tumor necrosis factor by ethyl-p-methoxycinnamate was significant in both in vivo and in vitro models; however, only a moderate inhibition of nitric oxide was observed in macrophages. Furthermore, ethyl-p-methoxycinnamate considerably inhibited microvessel sprouting from the rat aorta. These mechanistic studies showed that ethyl-p-methoxycinnamate strongly inhibited the differentiation and migration of endothelial cells, which was further confirmed by the reduced level of vascular endothelial growth factor.

CONCLUSION

Ethyl-p-methoxycinnamate exhibits significant anti-inflammatory potential by inhibiting pro-inflammatory cytokines and angiogenesis, thus inhibiting the main functions of endothelial cells. Thus, ethyl-p-methoxycinnamate could be a promising therapeutic agent for the treatment of inflammatory and angiogenesis-related diseases.

Targeting mast cells in inflammatory diseases

Although mast cells have long been known to play a critical role in anaphylaxis and other allergic diseases, they also participate in some innate immune responses and may even have some protective functions. Data from the study of mast cell-deficient mice have facilitated our understanding of some of the molecular mechanisms driving mast cell functions during both innate and adaptive immune responses. This review presents an overview of the biology of mast cells and their potential involvement in various inflammatory diseases. We then discuss some of the current pharmacological approaches used to target mast cells and their products in several diseases associated with mast cell activation.

The vascular permeabilizing factors histamine and serotonin induce angiogenesis through TR3/Nur77 and subsequently truncate it through thrombospondin-1

Angiogenesis plays an important role in cancer and in many other human diseases. Vascular endothelial growth factor-A (VEGF-A), the best known angiogenic factor, was originally discovered as a potent vascular permeability factor (VPF), suggesting that other vascular permeabilizing agents, such as histamine and serotonin, might also have angiogenic activity. We recently demonstrated that, like VEGF-A, histamine and serotonin up-regulate the orphan nuclear receptor and transcription factor TR3 (mouse homolog Nur77) and that TR3/Nur77 is essential for their vascular permeabilizing activities. We now report that histamine and serotonin are also angiogenic factors that, at low micromolar concentrations, induce endothelial cell proliferation, migration and tube formation in vitro, and angiogenesis in vivo. All of these responses are mediated through specific histamine and serotonin receptors, are independent of VEGF-A, and are directly dependent on TR3/Nur77. Initially, the angiogenic response closely resembled that induced by VEGF-A, with generation of "mother" vessels. However, after ~10 days, mother vessels began to regress as histamine and serotonin, unlike VEGF-A, up-regulated the potent angiogenesis inhibitor thrombospondin-1, thereby triggering a negative feedback loop. Thus, histamine and serotonin induce an angiogenic response that fits the time scale of acute inflammation.

The critical role of mast cell-derived hypoxia-inducible factor-1α in human and mice melanoma growth

Mast cells play an important role in tumorigenesis. Histamine released from mast cells stimulates new vessel formation by acting through the histamine1 (H1) receptor. Despite the evidence of the role of mast cells in tumor growth and angiogenesis, the potential mechanism remains to be elucidated. Therefore, we investigated the role of mast cell-derived HIF-1α in melanoma growth. Here, we identify that the most positive cells for HIF-1α staining are seen in mast cells of human and animal melanoma tissue. The number of the stromal cell types (fibroblasts, macrophages and endothelial cells) was also increased in melanoma tissues. In activated bone marrow-derived mast cells (BMMCs), expressions of HIF-1α and VEGF were increased. Histamine also induced the expressions of HIF-1α and VEGF in BMMCs. H1 receptor antagonists significantly improved overall survival rates and substantially suppressed tumor growth as well as the infiltration of mast cells and levels of VEGF through the inhibition of HIF-1α expression in B16F10 melanoma-bearing mice. Furthermore, the injection of HIF-1α depleted BMMCs markedly inhibited the growth of tumors and migration of mast cells and increased the survival rate of the mice. These findings emphasize that the growth of melanoma can actually be exacerbated by mast cell-derived HIF-1α. In aggregate, our results reveal a novel role for mast cell-derived HIF-1α in the melanoma microenvironment and have important implications for the design of therapeutic strategies.

Enhanced histamine production through the induction of histidine decarboxylase expression by phorbol ester in Jurkat cells

Histamine (HA), a mediator of inflammation, type I allergic responses and neurotransmission, is synthesized from L-histidine, the reaction of which is catalyzed by histidine decarboxylase (HDC). HDC has been reported to be induced by various stimuli, not only in mast cells and basophils, but also in T lymphocytes and macrophages. Although its mRNA has been shown to be increased in Jurkat cells when treated with phorbol 12-myristate 13-acetate (TPA), little is known concerning the induced production of HA by HDC. The present study quantified the trace amounts of intracellular HA using ultra-high liquid chromatography in combination with the 6-aminoquinoline carbamate-derivatization technique. To test whether the cellular level of HA is elevated by the induction of HDC in Jurkat cells treated with TPA, the peak corresponding to authentic HA in the cell lysate was fractioned and its molecular weight determined by matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry. The results of this study show that the HA level is increased by the induction of HDC expression by TPA in Jurkat cells. Therefore, this method is useful in elucidating the physiological significance of HA production.

Combinatorial roles for histamine H1-H2 and H3-H4 receptors in autoimmune inflammatory disease of the central nervous system

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system in which histamine (HA) and its receptors have been implicated in disease pathogenesis. HA exerts its effects through four different G protein-coupled receptors designated H(1)-H(4). We previously examined the effects of traditional single HA receptor (HR) knockouts (KOs) in experimental allergic encephalomyelitis (EAE), the autoimmune model of MS. Our results revealed that H(1) R and H(2) R are propathogenic, while H(3) R and H(4) R are antipathogenic. This suggests that combinatorial targeting of HRs may be an effective disease-modifying therapy (DMT) in MS. To test this hypothesis, we generated H(1) H(2) RKO and H(3) H(4) RKO mice and studied them for susceptibility to EAE. Compared with wild-type (WT) mice, H(1) H(2) RKO mice developed a less severe clinical disease course, whereas the disease course of H(3) H(4) RKO mice was more severe. H(1) H(2) RKO mice also developed less neuropathology and disrupted blood brain barrier permeability compared with WT and H(3) H(4) RKO mice. Additionally, splenocytes from immunized H(1) H(2) RKO mice produced less interferon(IFN)-γ and interleukin(IL)-17. These findings support the concept that combined pharmacological targeting of HRs may be an appropriate ancillary DMT in MS and other immunopathologic diseases.

Postexercise hypotension and sustained postexercise vasodilatation: what happens after we exercise?

A single bout of aerobic exercise produces a postexercise hypotension associated with a sustained postexercise vasodilatation of the previously exercised muscle. Work over the last few years has determined key pathways for the obligatory components of postexercise hypotension and sustained postexercise vasodilatation and points the way to possible benefits that may result from these robust responses. During the exercise recovery period, the combination of centrally mediated decreases in sympathetic nerve activity with a reduced signal transduction from sympathetic nerve activation into vasoconstriction, as well as local vasodilator mechanisms, contributes to the fall in arterial blood pressure seen after exercise. Important findings from recent studies include the recognition that skeletal muscle afferents may play a primary role in postexercise resetting of the baroreflex via discrete receptor changes within the nucleus tractus solitarii and that sustained postexercise vasodilatation of the previously active skeletal muscle is primarily the result of histamine H(1) and H(2) receptor activation. Future research directions include further exploration of the potential benefits of these changes in the longer term adaptations associated with exercise training, as well as investigation of how the recovery from exercise may provide windows of opportunity for targeted interventions in patients with hypertension and diabetes.

Histidine decarboxylase expression influences the neofolliculogenesis of newborn mouse dermal cells

BACKGROUND

With the introduction of hair regeneration techniques using epidermal and dermal cells, hair follicle regeneration became much easier and faster. Current success has been dependent on the availability of cells from newborn or embryonic mice. We recently observed that the hair-inducing ability of newborn mouse dermal cells disappeared in the first few days of life and there was a drastic decrease of histidine decarboxylase (HDC) gene expression from postnatal day 0 (p0) to day 7 (p7).

OBJECTIVE

The aim of this study was to study the role of HDC in hair follicle induction.

METHODS

The mRNA levels of HDC in p0, p7 and p48 C57BL/6 mouse skin were checked with a real time reverse transcription polymerase chain reaction and immunohistochemistry. To test the effect of HDC, HDC expression in p0 mouse dermal cells was suppressed with small interfering RNA (siRNA) transfection. Mock treated and HDC siRNA treated cells were then injected with adult epidermal cells into nude mice skin. Three weeks later, the number, length and thickness of induced hairs were compared.

RESULTS

Compared with p0, the mRNA level of HDC was much lower at p7 and p48. Immunohistochemical staining also revealed a marked decrease of HDC expression in p7 mice skin, compared with p0 skin. Hair patch assays showed that the HDC siRNA treated p0 dermal cells induced less hair follicle structures and shorter and thinner hair shafts than mock treated cells.

CONCLUSION

HDC, whose expression is remarkably downregulated during the first few days after birth in dermal cells of mice, plays essential roles in the hair-inducing ability of newborn mouse dermal cells.

A report on anti-oedemogenic activity of Byttneria herbacea roots--possible involvement of histamine receptor (type I)

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional healers of the Kol tribes of West Bengal, Bihar and Jharkhand (India), widely use the woody rootstock of Byttneria herbacea to reduce the swelling of limbs, due to filariasis. Besides filariasis different part of this plant is used for the treatment of cholera, diarrhoea and asthma.

AIM OF THIS STUDY

This study is a preliminary attempt to evaluate the anti-oedemogenic activity of the roots of Byttneria herbacea.

MATERIALS AND METHODS

The anti-oedemogenic activity of the hydroalcoholic extract of the roots of Byttneria herbacea (HBH) was evaluated against carrageenan and histamine induced rat paw oedema, acetic acid induced writhing and histamine induced vascular permeability in mice. Further, the effect of HBH on the expression of human histamine receptor type I (H1R) was studied in HeLa cells.

RESULTS

HBH exhibited significant dose-dependent inhibition (*p<0.05) against carrageenan and histamine induced rat paw oedema. Similar significant dose-dependent inhibition was observed against acetic acid induced writhing and histamine-induced vascular permeability in mice. Moreover, H1R specific mRNA expression was also significantly (*p<0.05) suppressed by HBH.

CONCLUSION

HBH was observed to possess anti-oedemogenic activity which is probably mediated through suppression of H1R.

Aryl hydrocarbon receptor negatively regulates LPS-induced IL-6 production through suppression of histamine production in macrophages

Macrophages play a pivotal role in innate immune responses to pathogens via toll-like receptors. We previously demonstrated that aryl hydrocarbon receptor (Ahr) in combination with signal transducer and activator of transcription 1 (Stat1) negatively regulates pro-inflammatory cytokine production by inhibiting nuclear factor-κB activation in macrophages after LPS stimulation. Here, we show that Ahr also negatively regulates production of the pro-inflammatory cytokine IL-6 by suppressing histamine production in macrophages stimulated by LPS. We found that Ahr-Sp1 complex, independent of Stat1, represses histidine decarboxylase expression by inhibiting LPS-induced Sp1 phosphorylation on Ser residues in macrophages; this leads to suppression of histamine production. Moreover, we found that loratadine and chlorpromazine, histamine 1 receptor (H1R) antagonists, more effectively impair the production of LPS-induced IL-6 than that of other inflammatory cytokines in Ahr(-/-) macrophages. Collectively, these results demonstrate that Ahr negatively regulates IL-6 production via H1R signaling through the suppression of histamine production in macrophages following LPS stimulation.

Mast cell modulation of the vascular and lymphatic endothelium

Mast cells (MCs) promote a wide range of localized and systemic inflammatory responses. Their involvement in immediate as well as chronic inflammatory reactions at both local and distal sites points to an extraordinarily powerful immunoregulatory capacity with spatial and temporal versatility. MCs are preferentially found in close proximity to both vascular and lymphatic vessels. On activation, they undergo a biphasic secretory response involving the rapid release of prestored vasoactive mediators followed by de novo synthesized products. Many actions of MCs are related to their capacity to regulate vascular flow and permeability and to the recruitment of various inflammatory cells from the vasculature into inflammatory sites. These mediators often work in an additive fashion and achieve their inflammatory effects locally by directly acting on the vascular and lymphatic endothelia, but they also can affect distal sites. Along these lines, the lymphatic and endothelial vasculatures of the host act as a conduit for the dissemination of MC signals during inflammation. The central role of the MC-endothelial cell axis to immune homeostasis is emphasized by the fact that some of the most effective current treatments for inflammatory disorders are directed at interfering with this interaction.

[Roles of histamine in the exacerbated allergic dermatitis]

We established a novel dermatitis model in mice earlobes and analyzed the roles of histamine using specific antagonists for histamine receptors. After sensitization with picryl chloride (PiCl) by painting it on the earlobes of cyclophosphamide-treated mice, 12-O-tetradecanoylphorbol 13-acetate (TPA) was painted twice at the same site, and then allergic inflammation was induced by painting with PiCl. Histamine antagonists and cyclosporin A were administered i.v. The application of TPA shifted the PiCl-induced allergic inflammation from a delayed-type response to a biphasic response and increased the infiltration of eosinophils and mast cells at the inflammatory site. In this model, the PiCl-induced increase in the thickness of the earlobe in the immediate phase was suppressed by the histamine H₁ antagonist pyrilamine. In contrast, the increase in the swelling in the late phase and the infiltration of eosinophils were suppressed by the H₃/H₄ antagonist thioperamide. The inhibitory effect of the combined treatment with pyrilamine and thioperamide on TPA-modified contact dermatitis was as potent as that of cyclosporin A. Histamine plays significant roles in early-phase swelling via H₁ receptors and in late-phase swelling via H₃/H₄ receptors in this TPA-modified allergic dermatitis model.

Activation of the central histaminergic system is involved in hypoxia-induced stroke tolerance in adult mice

We hypothesized that activation of the central histaminergic system is required for neuroprotection induced by hypoxic preconditioning. Wild-type (WT) and histidine decarboxylase knockout (HDC-KO) mice were preconditioned by 3 hours of hypoxia (8% O(2)) and, 48 hours later, subjected to 30 minutes of middle cerebral artery (MCA) occlusion, followed by 24 hours of reperfusion. Hypoxic preconditioning improved neurologic function and decreased infarct volume in WT or HDC-KO mice treated with histamine, but not in HDC-KO or WT mice treated with α-fluoromethylhistidine (α-FMH, an inhibitor of HDC). Laser-Doppler flowmetry analysis showed that hypoxic preconditioning ameliorated cerebral blood flow (CBF) in the periphery of the MCA territory during ischemia in WT mice but not in HDC-KO mice. Histamine decreased in the cortex of WT mice after 2, 3, and 4 hours of hypoxia, and HDC activity increased after 3 hours of hypoxia. Vascular endothelial growth factor (VEGF) mRNA and protein expressions showed a greater increase after hypoxia than those in HDC-KO or α-FMH-treated WT mice. In addition, the VEGF receptor-2 antagonist SU1498 prevented the protective effect of hypoxic preconditioning in infarct volume and reversed increased peripheral CBF in WT mice. Therefore, endogenous histamine is an essential mediator of hypoxic preconditioning. It may function by enhancing hypoxia-induced VEGF expression.

Involvement of prostaglandins and histamine in nickel wire-induced acute inflammation in mice

The irritancy of Nickel (Ni) ions has been well documented clinically. However, the chemical mediators involved in the acute inflammation induced by solid Ni are not fully understood. We used the Ni wire-implantation model in mice and examined roles of prostaglandins and histamine in plasma leakage in the acute phase. The subcutaneous implantation of a Ni wire into the back of mice induced plasma leakage from 8 to 24 h and tissue necrosis around the wire at 3 days, whereas the implantation of an aluminum wire induced no such inflammatory responses. An increase in the mRNA for cyclooxygenase (COX)-2 and HDC in cells around the Ni wire was detected 4 h after the implantation. The leakage of plasma at 8 h was inhibited by indomethacin in a dose-dependent manner. Dexamethasone and the p38 MAP kinase inhibitor SB203580 also inhibited the exudation of plasma consistent with the inhibition of the expression of COX-2 mRNA. Furthermore, plasma leakage was partially but siginificantly reduced in histamine H1 receptor knockout mice and histidine decarboxylase (HDC) knockout mice but not in H2 receptor knockout mice. These results suggested that the Ni ions released from the wire induced the expression of COX-2 and HDC, resulting in an increase in vascular permeability during the acute phase of inflammation.

Increased synthesis of vascular endothelial growth factor in allergic airway inflammation in histidine decarboxylase knockout (HDC(-/-)) mice

Histamine and vascular endothelial growth factor (VEGF) have been implicated in the pathogenesis of allergic asthma; they enhance inflammation, vascular permeability, and mucus secretion. Histamine was suggested to alter the level of VEGF via the H2 receptors. Here the authors have applied histidine decarboxylase gene-targeted (HDC(-/-)) mice, lacking histamine, to investigate the effect of histamine deficiency on VEGF expression in an animal model of asthma. HDC(-/-) and wild-type (WT) mice were sensitized and challenged with ovalbumin (OVA). VEGF mRNA expression and protein level were determined in the lung. Number of VEGF-positive immune cells of bronchoalveolar lavage (BAL) and their intracellular VEGF content were measured by flow cytometry. VEGF protein level in the lung and in the BAL cells was increased in OVA treated (HDC(-/-)(ova) as well as in WT(ova)) animals compared to their controls. However, there was no difference in the VEGF levels between HDC(-/-) or WT animals, either in the lung or in the BAL cells. In conclusion, increased VEGF production of the lung or BAL immune cells can be induced by allergen provocation independently from the genetic background of the animals. These data suggest that VEGF-mediated allergic processes can persist in the absence of histamine.

[Histamine as an immunomodulator]

The role of histamine as an important proinflammatory mediator has been well known for nearly 100 years. In regards to the immediate type allergic response, there is no debate about the importance of histamine. In addition, histamine has immunomodulatory functions, some of which are related to the histamine H2 receptor. However, with the discovery of the histamine H(4) receptor in the year 2000, the role of histamine as an immunomodulator became more obvious. The histamine H(4) receptor is expressed on several hematopoietic cells; along with the chemotaxis of immune cells, this recently characterized receptor modulates also the cytokine and chemokine secretion of some hematopoietic cells. Highly selective histamine H(4) receptor antagonists display promising results in animal models of allergic inflammatory diseases and also in in vitro studies on animal and human cells. These first results indicate that the histamine H(4) receptor is an interesting new pharmacological target for the treatment of allergic inflammatory disorders. This review summarizes the most important immunomodulatory functions of histamine and points to some possible indications in dermatology.

Group III secreted phospholipase A2 transgenic mice spontaneously develop inflammation

PLA2 (phospholipase A2) group III is an atypical sPLA2 (secretory PLA2) that is homologous with bee venom PLA2 rather than with other mammalian sPLA2s. In the present paper, we show that endogenous group III sPLA2 (PLA2G3) is expressed in mouse skin and that Tg (transgenic) mice overexpressing human PLA2G3 spontaneously develop skin inflammation. Pla2g3-Tg mice over 9 months of age frequently developed dermatitis with hyperkeratosis, acanthosis, parakeratosis, erosion, ulcer and sebaceous gland hyperplasia. The dermatitis was accompanied by infiltration of neutrophils and macrophages and by elevated levels of pro-inflammatory cytokines, chemokines and prostaglandin E2. In addition, Pla2g3-Tg mice had increased lymph aggregates and mucus in the airway, lymphocytic sialadenitis, hepatic extramedullary haemopoiesis, splenomegaly with increased populations of granulocytes and monocytes/macrophages, and increased serum IgG1. Collectively, these observations provide the first demonstration of spontaneous development of inflammation in mice with Tg overexpression of mammalian sPLA2.

Expression of non-mast cell histidine decarboxylase in tumor-associated microvessels in human esophageal squamous cell carcinomas

Histamine is produced by mast cells and many other types of cells. The role of histamine released from mast cells in promoting tumor angiogenesis has been intensively studied; however, the role of non-mast cell histamine in regulating tumor angiogenesis has been largely ignored. In this study, tissue specimen sections from 43 patients with esophageal squamous cell carcinoma (ESCC) and normal esophageal biopsies from 17 heath individuals obtained from a high incidence area of north China were used to assess changes in microvessel density (MVD) and non-mast cell L-histidine decarboxylase (HDC) (the only rate-limiting enzyme that catalyzes the formation of histamine from L-histidine) expression in the tumor microenvironment by immunohistochemistry (IHC). In addition, the cellular characterization of non-mast cell HDC-positive cells in microvessels was examined by double IHC combined with HDC/CD34 and HDC/PCNA antibodies. These IHC analyses revealed a significantly increased HDC-positive MVD in ESCC as compared with normal controls, which accounted for approximately 61% of CD34-labeled general MVD in ESCC. Furthermore, IHC in serial sections and double IHC showed that most of these HDC-positive cells were CD34-positive endothelial cells in microvessels with an increased proliferative capacity. Thus, our results suggest that non-mast cell histamine expressed in endothelial cells of microvessels could be an additional cellular source and might play a role in regulating angiogenesis in ESCC.