The role of mast cells in atrial natriuretic peptide-induced cutaneous inflammation

Atrial natriuretic peptide (ANP) is widely distributed throughout the heart, skin, gastrointestinal and genital tracts, and nervous and immune systems. ANP acts to mediate vasodilation and induces mast cell activation in both human and rats in vitro. However, the mechanisms of ANP-induced mast cell activation, the extent to which ANP can induce tissue swelling, mast cell degranulation, and granulocyte infiltration in mouse skin are not fully understood. This issue was investigated by treatment with ANP in rat peritoneal mast cells (RPMCs) and mouse peritoneal mast cells (MPMCs) in vitro and by injection of ANP into the skin of congenic normal WBB6F1/J-Kit+/Kit+ +/+, genetically mast cell-deficient WBB6F1/J-Kit(W)/Kit(W-v) (W/W(v)) and mast cell-engrafted W/W(v) (BMCMC→W/W(v)) mice in vivo. ANP induced the release of histamine and TNF-α from RPMCs and enhanced serotonin release from MPMCs, in a dose-dependent fashion, as well as reduced cAMP level of RPMCs in vitro. In +/+ mice, ANP induced significant tissue swelling, mast cell degranulation, and granulocyte infiltration in a dose-dependent manner, whereas not in genetically mast cell-deficient W/W(v) mice. However, ANP-induced cutaneous inflammation has been restored in BMCMC→W/W(v) mice. These data indicate that mast cells play a key role in the ANP-induced cutaneous inflammation.     

Atrial peptides induce mast cell histamine release.

Human atrial natriuretic peptide [ANF(1-28)] contains five arginine residues and carries an overall positive change of four. It was hypothesized that atrial peptides may induce mast cell histamine release. In vitro, three atrial peptides [ANF(1-28), (3-28) and (5-28)] were demonstrated to induce dose-dependent histamine release from isolated rat peritoneal mast cells. In vivo, ANF(3-28) produced a dose-dependent increase in rat skin permeability which was blocked by antagonists of histamine and serotonin. The results indicate atrial peptides are capable of inducing mast cell degranulation in a manner similar to that described for other positively charged peptides.     

Dendroaspis natriuretic peptide-like immunoreactivity and its regulation in rat aortic vascular smooth muscle

Dendroaspis natriuretic peptide (DNP) is a recently isolated 38 amino acid peptide that shares structural and functional properties with the other members of the natriuretic peptide family. The present study demonstrates the presence of DNP-like immunoreactivity in sections of rat aorta, carotid artery and renal vasculature and tubules. DNP-like immunoreactivity was detected in culture aortic vascular smooth muscle cells and medium and is regulated by endothelin-1, angiotensin II and sodium nitroprusside but not by transforming growth factor-beta. Our observations indicate that DNP elicits a marked inhibitory effect on DNA synthesis in culture rat aortic vascular smooth muscle cells.     

Response of cardiac mast cells to atrial natriuretic peptide

Previously, our laboratory demonstrated that cardiac mast cell degranulation induces adverse ventricular remodeling in response to chronic volume overload. The purpose of this study was to investigate whether atrial natriuretic peptide (ANP), which is known to be elevated in chronic volume overload, causes cardiac mast cell degranulation. Relative to control, ANP induced significant histamine release from peritoneal mast cells, whereas isolated cardiac mast cells were not responsive. Infusion of ANP (225 pg/ml) into blood-perfused isolated rat hearts produced minimal activation of cardiac mast cells, similar to that seen in the control group. ANP also did not increase matrix metalloproteinase-2 activity, reduce collagen volume fraction, or alter diastolic or systolic cardiac function compared with saline-treated controls. In a subsequent study to evaluate the effects of natriuretic peptide receptor antagonism on volume overload-induced ventricular remodeling, anantin was administered to rats with an aortocaval fistula. Comparable increases of myocardial MMP-2 activity in treated and untreated rats with an aortocaval fistula were associated with equivalent decreases in ventricular collagen (P < 0.05 vs. sham-operated controls). Cardiac functional parameters and left ventricular hypertrophy were unaffected by anantin. We conclude that ANP is not a cardiac mast cell secretagogue and is not responsible for the cardiac mast cell-mediated adverse ventricular remodeling in response to volume overload.     

Dendroaspis natriuretic peptide and its functions in pig ovarian granulosa cells

Dendroaspis natriuretic peptide (DNP), a 38-amino acid peptide, was isolated from the venom of green mamba. It has structural and functional similarities to the other members of the natriuretic peptide family. The purpose of this study was to determine whether DNP is present in pig ovarian granulosa cells and to define its biological functions. The serial dilution curves of extracts of granulosa cells and follicular fluid were parallel to the standard curve of DNP, and a major peak of molecular profile of both extracts by HPLC was synthetic DNP. The concentration of DNP was 7.51+/-1.46 pg/10(7) cells and 24.81+/-2.38 pg/ml in granulosa cells and follicular fluid, respectively. Natriuretic peptides increased cGMP production in the purified membrane of granulosa cells with a rank order of potency of C-type natriuretic peptide (CNP)>atrial natriuretic peptide (ANP)=DNP. mRNAs for natriuretic peptide receptor-A (NPR-A), NPR-B and NPR-C were detected by RT-PCR. The binding site of (125)I-DNP was also observed in granulosa cell layer by in vitro autoradiography. Synthetic DNP inhibited the secretion of ANP from granulosa cells in a concentration-dependent manner and the potency was similar to CNP. The concentration of DNP and CNP, which inhibited the secretion of ANP by 50%, was about 1 nM. Increases in production of cGMP in granulosa cells were observed by DNP or CNP. Therefore, these results show the existence of DNP system and the cross-talk between natriuretic peptides in pig ovarian granulosa cells.     

A new member of the natriuretic peptide family is present in the venom of the green mamba (Dendroaspis angusticeps).

This paper describes the purification, sequence, and biological properties of a 38-amino acid residue peptide from the venom of Dendroaspis angusticeps which shared important sequence homologies with natriuretic peptides. Dendroaspis natriuretic peptide (DNP) relaxed aortic strips that had been contracted by 40 mM KCl with a potency (K0.5 = 20 nM) similar to that of atrial natriuretic peptide (ANP) and larger than that of C type natriuretic peptide (CNP). The relaxing actions of ANP and DNP (both at 100 nM) were mutually exclusive. Bovine aortic endothelial cells responded to ANP (K0.5 = 3 nM) and DNP (K0.5 = 3 nM) but not to CNP by a large activation of guanylate cyclase. Rat aortic myocytes showed larger cGMP responses to CNP (K0.5 = 10 nM) than to ANP or DNP (K0.5 = 100 nM). Finally, DNP completely prevented the specific 125I-ANP binding to clearance receptors in cultured aortic myocytes with a potency (Kd = 10 nM) that was less than that of ANP (Kd = 0.3 nM). It is concluded that DNP is a new member of the family of natriuretic peptides and that it recognizes ANPA receptors and clearance, ANPc receptors, but not CNP-specific ANPB receptors.     

Dendroaspis natriuretic peptide system and its paracrine function in rat colon

Dendroaspis natriuretic peptide (DNP), a 38-amino-acid peptide, was isolated from the venom of Green Mamba. It has structural and functional similarities to other members of the natriuretic peptide family. The purpose of this study was to determine whether DNP system is present in the rat colon and to define its biological functions. The serial dilution curve of extracts of colonic tissues was parallel to the standard curve of DNP and a major peak of molecular profile by HPLC was synthetic DNP. The concentration of DNP was 0.5±0.04 ng/g of colonic tissues. DNP as well as atrial natriuretic peptide and C-type natriuretic peptide caused dose-dependent increases in cGMP production in the purified membrane of colonic tissues. Three types of natriuretic peptide receptor mRNAs were detected using semi-quantitative RT-PCR. Functionally, synthetic DNP inhibited the spontaneous contraction of rat colonic circular muscle in a concentration-dependent manner. The potency appeared to be at least 10 times greater than that of CNP. Furthermore, DNP inhibited carbachol-induced muscle contraction, suggesting that it also can modulate the nerve regulation of colonic motility. This study demonstrates the presence of DNP system in rat colon and its function as a local regulator of colonic motility.     

Histamine is involved in gastric vasodilation during acid back diffusion via activation of sensory neurons

Protective vasodilation during acid back diffusion into the rat gastric mucosa depends on activation of sensory neurons and mast cell degranulation with histamine release. We hypothesized that these two mediator systems interact and that histamine partly exerts its effect via sensory nerves. Gastric blood flow (GBF) and luminal histamine were measured in chambered stomachs, and mast cell numbers were assessed by morphometry. Ablation of sensory neurons and depletion of mast cells were produced by pretreatment with capsaicin or dexamethasone, respectively. Mucosal exposure to 1.5 M NaCl and then to pH 1.0 saline in ablated and control rats caused increased luminal histamine and reduced numbers of mast cells. Enterochromaffin-like cell marker pancreastatin remained unchanged. Only control rats responded with an increase in GBF. Capsaicin stimulation (640 microM) of the undamaged mucosa induced identical increase in GBF and unchanged mast cell mass in normal and dexamethasone-treated rats. Increase in GBF after topical exposure to histamine (30 mM) in rats pretreated with capsaicin or a calcitonin gene-related peptide (CGRP)(1) antagonist human CGRP(8-37) or exposed to the calcium pore blocker ruthenium red was less than one-half of that in control rats. These data suggest that mast cell-derived histamine is involved in gastric vasodilatation during acid back diffusion partly via sensory neurons.     

Observations of Forsythia koreana methanol extract on mast cell-mediated allergic reactions in experimental models

To explore effects of Forsythia koreana methanol extract (FKME) on mast cell-mediated allergic and inflammatory properties, the effect of FKME was evaluated on compound 48/80-induced systemic anaphylaxis, ear swelling, and anti-dinitrophenyl (DNP) immunoglobulin E (IgE)-induced passive cutaneous anaphylaxis (PCA). In addition, the effect of FKME was investigated on the histamine release from rat peritoneal mast cells (RPMCs) stimulated by compound 48/80, which promotes histamine release. The human mast cell line HMC-1 was stimulated by phorbol 12-myristate 13-acetate plus calcium ionophore A23187. Activated HMC-1 can produce several proinflammatory and chemotactic cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-8. Cytokine levels in the culture supernatant were measured by an enzyme-linked immunosorbent assay. Cytotoxicity by FKME was determined by a 3-(4,5-dimethylthiazol-2-yl)-diphenyl-tetrazolium bromide (MTT) assay. FKME inhibited compound 48/80-induced systemic anaphylactic shock and ear swelling in mice. When 1 g/kg FKME was pretreated or posttreated with mice, compound 48/80-induced mice morality was 50 and 66.7%, respectively. One gram per kilogram of FKME pretreatment inhibited ear-swelling responses derived from compound 48/80 by 29.75%. A PCA reaction was inhibited by 17.9%. In an in vitro model, FKME (1 mg/ml) inhibited histamine release from the RPMCs by 13.8% and TNF-α, IL-6, and IL-8 production from HMC-1 cells by 71.16% (P < 0.001), 86.72% (P < 0.001), and 44.6%, respectively. However, FKME had no cytotoxic effects on cell viability. In conclusion, FKME inhibited not only systemic anaphylaxis and ear swelling induced by compound 48/80 but also inhibited a PCA reaction induced by anti-DNP IgE in vivo. Treatment with FKME showed significant inhibitory effects on histamine, TNF-α, IL-6, and IL-8 release from mast cells.     

Functional and biochemical characterization of rat bone marrow derived mast cells

The functional and biochemical characterization of rat bone marrow derived mast cells (RBMMC) confirms both species-related differences between rat and mouse bone marrow-derived mast cells (MBMMC) as well as mast cell heterogeneity in a single species. Such RBMMC have the staining characteristics of mucosal mast cells and contain the mucosal mast cell protease. The RBMMC release the preformed granule mediator beta-hexosaminidase both in response to immunologic stimulation with 200 ng Ag (net release 15.8 +/- 3.8%) and in response to 1 microM calcium ionophore A23187 (net release 21.8 +/- 6.8%). However, compound 48/80, substance P, and somatostatin did not induce mast cell degranulation. In experiments with optimal beta-hexosaminidase release, the RBMMC generated similar quantities of the newly formed arachidonic acid metabolites leukotriene C4 and PGD2 when stimulated with either Ag or calcium ionophore A23187. The RBMMC incorporate [35S]sulfate into proteoglycans consisting of 90% chondroitin sulfates and 10% heparin. The chondroitin sulfates were comprised of chondroitin 4 sulfate and chondroitin sulfate diB sulfated disaccharides in a ratio of 4/1. Although we show that RBMMC and MBMMC share a low histamine content, functional IgE receptors and unresponsiveness to cromolyn and selective secretagogues (compound 48/80, substance P, and somatostatin), we also provide evidence that RBMMC differ from MBMMC in their profile of newly generated mediators, preformed granule proteoglycan, and lack of proliferative response to mouse IL-3.     

Accumulation of low density lipoproteins in stimulated rat serosal mast cells during recovery from degranulation

Stimulation of rat serosal mast cells in vitro with compound 48/80, a degranulating agent, resulted in an immediate increase in binding of low density lipoproteins (LDL) to the stimulated mast cells. The increase in binding was dose-dependent and closely followed the increase in histamine release, i.e., the exocytosis of mast cell granules. It could be demonstrated that the LDL were bound to exocytosed secretory granules which remained cell-associated. During the recovery period the granule-bound LDL were internalized by the mast cells along with the granules. A single stimulation of mast cells rendered their cytoplasm to be filled with granular material showing positive staining for both apoB and neutral lipid. This change was accompanied by a 30-fold increase in the cellular content of cholesteryl esters. Thus, rat serosal mast cells possess a specific mechanism for uptake of LDL that is activated by stimuli that lead to degranulation, the result being massive uptake of LDL by stimulated mast cells during recovery from degranulation.     

Stem cell factor has histamine releasing activity in rat connective tissue-type mast cells.

Stem cell factor (SCF) was documented to be involved in the growth of mast cells controlled by fibroblasts. We tested the effect of recombinant rat SCF on degranulation from rat peritoneal mast cells (connective tissue-type mast cells: CTMC). SCF induced histamine release (approximately 20% of total histamine content) in a dose-dependent fashion. The release response was relatively rapid and reached a maximum within 5 min. The release showed total dependence on the presence of extracellular phosphatidylserine (PTS). These results reveal that SCF has histamine releasing activity in CTMC.     

Carnosine attenuates mast cell degranulation and histamine release induced by oxygen-glucose deprivation

Carnosine (beta-alanyl-histidine) is a naturally occurring dipeptide that has been characterized as a putative hydrophilic antioxidant. The protective function of carnosine has been demonstrated in neuronal cells under ischemic injury. The purpose of this study was to investigate the effects of carnosine on oxygen-glucose deprivation (OGD)-induced degranulation and histamine release from mast cells. Cultured mast cells were exposed to OGD for 4 h, and then the degranulation was observed immediately by microscopy. Histamine release was analyzed by high-performance liquid chromatography (HPLC). OGD caused degranulation of mast cells, and increased histamine and lactate dehydrogenase (LDH) release. Carnosine (at a concentration of 5 mM) alone did not produce any appreciable effect on degranulation, histamine, and LDH release from mast cells under normal condition, but significantly inhibited the degranulation, histamine, and LDH release of mast cells induced by OGD. These results indicate that carnosine can protect mast cells from degranulation and histamine release and it may be an endogenous mast cell stabilizer in the pathological processes induced by ischemia.     

The presence of ANP in rat peritoneal mast cells

Atrial natriuretic peptide （ANP） is an important component of the natriuretic peptide system. A great role in many regulatory systems is played by mast cells. Meanwhile involvement of these cells in ANP activity is poorly studied. In this work, we have shown the presence of ANP in rat peritoneal mast cells. Pure fraction of mast cells was obtained by separation of rat peritoneal cells on a Percoll density gradient. By Westem blotting, two ANP-immunoreactive proteins of molecular masses of 2.5 kDa and 16.9 kDa were detected in lysates from these mast cells. Electron microscope immunogold labeling has revealed the presence of ANP-immunoreactive material in storage, secreting and released granules of mast cells. Our findings indicate the rat peritoneal mast cells to contain both ANP prohormone and ANP. These both peptides are located in mast cell secretory granules and released by mechanism of degranulation. It is discussed that many mast cell functions might be due to production of natriuretic peptides by these cells.     

Inhibitory effect of diethylstilbestrol on histamine release by rat mast cells and its relation to the cellular ATP content

The effect of diethylstilbestrol, a synthetic estrogen, on mast cell secretion was investigated. The results showed that 50 microM diethylstilbestrol inhibited histamine release from rat peritoneal mast cells in the presence and absence of glucose, but did not affect 45Ca uptake stimulated by concanavalin A. Diethylstilbestrol also inhibited histamine release induced by compound 48/80, exogenous ATP, or ionophore A23187. Since estradiol benzoate, hexestrol and daidzein were not inhibitory, the inhibitory action of diethylstilbestrol must be independent of its estrogenic activity. The ATP content of mast cells decreased to less than 0.1 nmol/10(6) cells on treatment with 50 microM diethylstilbestrol at 37 degrees C for 15 min. This effect of diethylstilbestrol in decreasing the ATP content of mast cells correlated well with its inhibitory effect on histamine release. Diethylstilbestrol at 50 microM depleted the cells of ATP at 37 degrees C, but not at 0 degrees C, whereas [3H]diethylstilbestrol ( [monoethyl-3H]diethylstilbestrol) binding to rat mast cells was the same at 0 and 37 degrees C. It is concluded that diethylstilbestrol reduced the ATP content of rat mast cells by inhibiting metabolism of the cells, and consequently inhibited degranulation.     

Role of bradykinin in gastric vasodilation caused by hypertonic saline and acid back diffusion

Protective vasodilation in response to tissue injury and acid back diffusion is associated with release of bradykinin in the rat stomach. We hypothesized that bradykinin might be involved in mechanisms behind such vasodilation via influence on mast cells and sensory neurons. Acid back diffusion after mucosal barrier disruption with hypertonic saline evoked degranulation of mast cells in the rat stomach wall. Acid back diffusion was also associated with increased luminal release of histamine and gastric blood flow in normal rats, but not in mast cell-deficient rats. Bradykinin (BK(2)) receptor blockade inhibited degranulation of submucosal mast cells in the stomach and attenuated gastric vasodilation both in response to acid back diffusion and after stimulation of sensory neurons with capsaicin. Gastric vasodilation caused by mucosal injury with hypertonic saline alone was associated with degranulation of mucosal mast cells. These events were unaffected by inhibition of prostaglandin synthesis, whereas bradykinin (BK(2)) receptor blockade was associated with abolished vasodilation and inhibition of mucosal mast cell degranulation. We conclude that bradykinin is involved in gastric vasodilation caused by hypertonic injury alone via influence on mast cells, and by acid back diffusion via influence on both sensory neurons and mast cells.     

Lipopolysaccharides and lipoteichoic acids stimulate rat mast cells to cysteinyl leukotriene synthesis

We have investigated the ability of lipopolysaccharides (LPS) and lipoteichoic acids (LTA) to induce rat peritoneal mast cells to degranulation and histamine release, and to cysteinyl leukotriene (LT) generation. We have stated that LPS Salmonella Enteritidis, LPS Escherichia coli O111:B4 and LPS E. coli O55:B5 did not activate rat mast cells to degranulation and histamine release. However, LPSs induced LT synthesis and secretion; the strongest stimulant to generation of LT was LPS E. coli O55:B5 (concentration of LT in supernatant was 830.5 +/-15.2 pg/ml). We have also observed that LTA Staphylococcus aureus and LTA Bacillus subtilis stimulated rat mast cells to degranulation and histamine secretion, even though the percentage of the releases histamine was relatively low (10.0 +/- 1.4 and 10.4 +/- 5.4 at antigen concentration, respectively). At the same time, LTA of both of the bacterial species strongly activate LT generation by mast cells (concentrations of LT in supernatants were 777.9 +/- 11.2 pg/ml and 734.0 +/- 38.3 pg/ml, respectively, at the antigen concentration 50 ng/ml). Our results have shown that LPS oraz LTA activate rat mast cells to secretion of proinflammatory mediators.     

Mast cell degranulating (MCD) peptide: a prototypic peptide in allergy and inflammation.

The solid phase synthesis of mast degranulating peptide (MCD peptide) raised the possibility of preparing analogs and examining the pharmacology and the proposed role of this peptide as a potential agent in allergy and inflammation. MCD peptide, a cationic 22-amino acid residue peptide with two disulfide bridges, causes mast cell degranulation and histamine release at low concentrations and has anti-inflammatory activity at higher concentrations. Because of these unique immunologic properties, MCD peptide may serve as a useful tool for studying secretory mechanisms of inflammatory cells such as mast cells, basophils, and leukocytes, leading to the design of compounds with therapeutic potential.     

Neutrophil defensins induce histamine secretion from mast cells: mechanisms of action.

Defensins are endogenous antimicrobial peptides stored in neutrophil granules. Here we report that a panel of defensins from human, rat, guinea pig, and rabbit neutrophils all have histamine-releasing activity, degranulating rat peritoneal mast cells with EC50 ranging from 70 to 2500 nM, and between 45 and 60% of the total histamine released. The EC50 for defensin-induced histamine secretion correlates with their net basic charge at neutral pH. There is no correlation between histamine release and antimicrobial potency. Degranulation induced by defensins has characteristics similar to those of activation by substance P. The maximum percent histamine release is achieved in <10 s, and it can be markedly inhibited by pertussis toxin (100 ng/ml) and by pretreatment of mast cells with neuraminidase. These properties differ from those for degranulation induced by IgE-dependent Ag stimulation and by the calcium ionophore A23187. GTPase activity, a measure of G protein activation, was induced in a membrane fraction from mast cells following treatment with defensin. Thus, neutrophil defensins are potent mast cell secretagogues that act in a manner similar to substance P and 48/80, through a rapid G protein-dependent response that is mechanistically distinct from Ag/IgE-dependent mast cell activation. Defensins may provide important pathways for communication between neutrophils and mast cells in defenses against microbial agents and in acute inflammatory responses.     

Regulation of adhesion of mouse bone marrow-derived mast cells to laminin

We have reported that mast cells adhere to laminin after activation with PMA. In this study, we demonstrate that the cross-linking of cell surface high-affinity IgE-R on mast cells derived from mouse bone marrow cultured for 3 wk in the presence of WEHI-3-conditioned media acts as a highly sensitive physiologic stimulus for this attachment and that receptor activation is also induced by calcium ionophore A23187. Adherence occurred at threefold log concentrations less of A23187 and Ag than required for histamine release in a selective subpopulation comprising 20 to 30% of the total cells. At higher concentrations of agonist that permitted histamine release, the time course for degranulation was shown to be more rapid than that of adherence. Adherence was inhibited by antibodies to laminin and laminin receptor and was calcium ion and temperature dependent. Treatment of cells with dibutyryl cAMP, which activates protein kinase A, inhibited both adherence and histamine release induced by Ag or calcium ionophore. Treatment of cells with staurosporin, which inhibits protein kinase C, also inhibited adherence and histamine release induced by calcium ionophore, but was not significantly active against either adherence or histamine release induced by Ag. It thus appears that agents which modulate intracellular signaling mechanisms are equally effective toward histamine release and adherence, suggesting these two events are intimately linked in stimulus secretion coupling. Specific cytokines stimulating mast cell adhesion to laminin could not be found; however, culture of mast cells with TGF-beta 1 was determined to enhance IgE-mediated adherence to laminin. Hence, the high-affinity IgE-R on the mast cell functions not only in exocytosis but also facilitates the process of mast cell adherence to laminin.