Induction of histidine decarboxylase in mouse tissues by mitogens in vivo

Histamine deficiency inhibits lymphocyte infiltration in the submandibular gland of aged mice via increased anti-aging factor Klotho

OBJECTIVES

Histidine decarboxylase (HDC), a histamine synthase, is expressed in various tissues and is induced by proinflammatory cytokines such as TNFα. As they age, C57BL/6 mice show auto-antibody deposition and lymphocyte infiltration into various tissues, including salivary glands. However, the mechanism underlying cell infiltration and the change in HDC expression in salivary glands with aging remain unclear. Thus, we aimed to elucidate the relationship between histamine and inflammaging.

METHODS

We investigated the change in histology and HDC expression in the major salivary glands (parotid, submandibular, and sublingual) of 6-week- and 9-month-old wild-type mice. We also determined the histological changes, cytokine expression, and anti-aging factor Klotho in the salivary glands of 9-month-old wild-type and HDC-deficient (HDC-KO) mice.

RESULTS

Cell infiltration was observed in the submandibular gland of 9-month-old wild-type mice. Although most cells infiltrating the submandibular glands were CD3-positive and B220-positive lymphocytes, CD11c-positive and F4/80-positive monocyte lineages were also detected. HDC, TNFα, and IL-1β mRNA expression increased in the submandibular gland of 9-month-old wild-type mice. The expression of PPARγ, an anti-inflammatory protein, declined in 9-month-old wild-type mice, and Klotho expression increased in 9-month-old HDC-KO mice. Immunohistochemistry showed that Klotho-positive cells disappeared in the submandibular gland of 9-month-old wild-type mice, while Klotho was detected in all salivary glands in HDC-KO mice of the same age.

CONCLUSION

Our findings demonstrate the multifunctionality of histamine and can aid in the development of novel therapeutic methods for inflammatory diseases such as Sjogren's syndrome and age-related dysfunctions.

[Basic Studies on the Mechanism, Prevention, and Treatment of Osteonecrosis of the Jaw Induced by Bisphosphonates]

Since the first report in 2003, bisphosphonate-related osteonecrosis of the jaw (BRONJ) has been increasing, without effective clinical strategies. Osteoporosis is common in elderly women, and bisphosphonates (BPs) are typical and widely used anti-osteoporotic or anti-bone-resorptive drugs. BRONJ is now a serious concern in dentistry. As BPs are pyrophosphate analogues and bind strongly to bone hydroxyapatite, and the P-C-P structure of BPs is non-hydrolysable, they accumulate in bones upon repeated administration. During bone-resorption, BPs are taken into osteoclasts and exhibit cytotoxicity, producing a long-lasting anti-bone-resorptive effect. BPs are divided into nitrogen-containing BPs (N-BPs) and non-nitrogen-containing BPs (non-N-BPs). N-BPs have far stronger anti-bone-resorptive effects than non-N-BPs, and BRONJ is caused by N-BPs. Our murine experiments have revealed the following. N-BPs, but not non-N-BPs, exhibit direct and potent inflammatory/necrotic effects on soft-tissues. These effects are augmented by lipopolysaccharide (the inflammatory component of bacterial cell-walls) and the accumulation of N-BPs in jawbones is augmented by inflammation. N-BPs are taken into soft-tissue cells via phosphate-transporters, while the non-N-BPs etidronate and clodronate inhibit this transportation. Etidronate, but not clodronate, has the effect of expelling N-BPs that have accumulated in bones. Moreover, etidronate and clodronate each have an analgesic effect, while clodronate has an anti-inflammatory effect via inhibition of phosphate-transporters. These findings suggest that BRONJ may be induced by phosphate-transporter-mediated and infection-promoted mechanisms, and that etidronate and clodronate may be useful for preventing and treating BRONJ. Our clinical trials support etidronate being useful for treating BRONJ, although additional clinical trials of etidronate and clodronate are needed.

Dynamics of Platelet Behaviors as Defenders and Guardians: Accumulations in Liver, Lung, and Spleen in Mice

Systemic platelet behaviors in experimental animals are often assessed by infusion of isotope-labeled platelets and measuring them under anesthesia. However, such procedures alter, therefore may not reveal, real-life platelet behaviors. 5-Hydroxytryptamine (5HT or serotonin) is present within limited cell-types, including platelets. In our studies, by measuring 5HT as a platelet-marker in non-anesthetized mice, we identified stimulation- and time-dependent accumulations in liver, lung, and/or spleen as important systemic platelet behaviors. For example, intravenous, intraperitoneal, or intragingival injection of lipopolysaccharide (LPS, a cell-wall component of Gram-negative bacteria), interleukin (IL)-1, or tumor necrosis factor (TNF)-α induced hepatic platelet accumulation (HPA) and platelet translocation into the sinusoidal and perisinusoidal spaces or hepatocytes themselves. These events occurred "within a few hours" of the injection, caused hypoglycemia, and exhibited protective or causal effects on hepatitis. Intravenous injection of larger doses of LPS into normal mice, or intravenous antigen-challenge to sensitized mice, induced pulmonary platelet accumulation (PPA), as well as HPA. These reactions occurred "within a few min" of the LPS injection or antigen challenge and resulted in shock. Intravenous injection of 5HT or a catecholamine induced a rapid PPA "within 6 s." Intravenous LPS injection, within a minute, increased the pulmonary catecholamines that mediate the LPS-induced PPA. Macrophage-depletion from liver and spleen induced "day-scale" splenic platelet accumulation, suggesting the spleen is involved in clearing senescent platelets. These findings indicate the usefulness of 5HT as a marker of platelet behaviors, and provide a basis for a discussion of the roles of platelets as both "defenders" and "guardians."

Interleukin-1 and histamine are essential for inducing nickel allergy in mice

BACKGROUND

We previously reported that (a) lipopolysaccharide (LPS) is a potent adjuvant for inducing Nickel (Ni) allergy in mice at both the sensitization and elicitation steps, (b) LPS induces Interleukin-1 (IL-1) and histidine decarboxylase (HDC, the histamine-forming enzyme), and IL-1 induces HDC, (c) Ni allergy is induced in mast cell-deficient, but not IL-1-deficient (IL-1-KO) or HDC-KO mice.

OBJECTIVE

To examine the roles of IL-1 and HDC (or histamine) and their interrelationship during the establishment of Ni allergy.

METHODS

Ni (NiCl₂ ) 1 mmol/L containing IL-1β and/or histamine was injected intraperitoneally (sensitization step). Ten days later, test substance(s) were intradermally injected into ear pinnas (elicitation step), and ear swelling was measured.

RESULTS

In wild-type mice, Ni + LPS or Ni + IL-1β injection at sensitization step followed by Ni alone at elicitation step induced Ni allergy. In IL-1-KO, injection of Ni + IL-1β (but not Ni + histamine) was required at both sensitization and elicitation steps to induce Ni allergy. In HDC-KO, Ni + IL-1β + histamine at sensitization step followed by Ni + histamine at elicitation step induced Ni allergy. In histamine H1 receptor-deficient mice, IL-1β induced HDC, but was ineffective as an adjuvant for inducing Ni allergy. In wild-type mice, injection into ear pinnas of Ni 10 mmol/L alone or Ni 1 mmol/L + LPS induced IL-1β, HDC and a prolonged swelling of ear pinnas. In non-sensitized mice, injection of IL-1β by itself into ear pinnas in IL-1-KO mice induced prolonged ear swelling. Ni augmented IL-1 production (both IL-1α and IL-1β) and HDC induction in wild-type mice sensitized to Ni.

CONCLUSIONS

In mice: (a) for inducing Ni allergy, IL-1 is essential at both the sensitization and elicitation steps, and HDC induction is involved in the effect of IL-1, (b) stimulation of H1 receptor is also essential for inducing Ni allergy at both sensitization and elicitation steps, and (c) the 'sensitization to Ni' state may be a state where tissues are primed for augmented production of IL-1α and/or IL-1β in response to Ni. (within 300 words, now 300).

Induction of the Histamine-Forming Enzyme Histidine Decarboxylase in Skeletal Muscles by Prolonged Muscular Work: Histological Demonstration and Mediation by Cytokines

Recent studies suggest that histamine-a regulator of the microcirculation-may play important roles in exercise. We have shown that the histamine-forming enzyme histidine decarboxylase (HDC) is induced in skeletal muscles by prolonged muscular work (PMW). However, histological analysis of such HDC induction is lacking due to appropriate anti-HDC antibodies being unavailable. We also showed that the inflammatory cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-α can induce HDC, and that PMW increases both IL-1α and IL-1β in skeletal muscles. Here, we examined the effects (a) of PMW on the histological evidence of HDC induction and (b) of IL-1β and TNF-α on HDC activity in skeletal muscles. By immunostaining using a recently introduced commercial polyclonal anti-HDC antibody, we found that cells in the endomysium and around blood vessels, and also some muscle fibers themselves, became HDC-positive after PMW. After PMW, TNF-α, but not IL-1α or IL-1β, was detected in the blood serum. The minimum intravenous dose of IL-1β that would induce HDC activity was about 1/10 that of TNF-α, while in combination they synergistically augmented HDC activity. These results suggest that PMW induces HDC in skeletal muscles, including cells in the endomysium and around blood vessels, and also some muscle fibers themselves, and that IL-1β and TNF-α may cooperatively mediate this induction.

Underlying Mechanisms and Therapeutic Strategies for Bisphosphonate-Related Osteonecrosis of the Jaw (BRONJ)

Bisphosphonates (BPs), with a non-hydrolysable P-C-P structure, are cytotoxic analogues of pyrophosphate, bind strongly to bone, are taken into osteoclasts during bone-resorption and exhibit long-acting anti-bone-resorptive effects. Among the BPs, nitrogen-containing BPs (N-BPs) have far stronger anti-bone-resorptive effects than non-N-BPs. In addition to their pyrogenic and digestive-organ-injuring side effects, BP-related osteonecrosis of jaws (BRONJ), mostly caused by N-BPs, has been a serious concern since 2003. The mechanism underlying BRONJ has proved difficult to unravel, and there are no solid strategies for treating and/or preventing BRONJ. Our mouse experiments have yielded the following results. (a) N-BPs, but not non-N-BPs, exhibit direct inflammatory and/or necrotic effects on soft tissues. (b) These effects are augmented by lipopolysaccharide, a bacterial-cell-wall component. (c) N-BPs are transported into cells via phosphate transporters. (d) The non-N-BPs etidronate (Eti) and clodronate (Clo) competitively inhibit this transportation (potencies, Clo>Eti) and reduce and/or prevent the N-BP-induced inflammation and/or necrosis. (e) Eti, but not Clo, can expel N-BPs that have accumulated within bones. (f) Eti and Clo each have an analgesic effect (potencies, Clo>Eti) via inhibition of phosphate transporters involved in pain transmission. From these findings, we propose that phosphate-transporter-mediated and inflammation/infection-promoted mechanisms underlie BRONJ. To treat and/or prevent BRONJ, we propose (i) Eti as a substitution drug for N-BPs and (ii) Clo as a combination drug with N-BPs while retaining their anti-bone-resorptive effects. Our clinical trials support this role for Eti (we cannot perform such trials using Clo because Clo is not clinically approved in Japan).

Mast cell histamine-mediated transient inflammation following exposure to nickel promotes nickel allergy in mice

We previously reported that allergic responses to nickel (Ni) were minimal in mice deficient in the histamine-forming enzyme histidine decarboxylase (HDC-KO), suggesting an involvement of histamine in allergic responses to Ni. However, it remains unclear how histamine is involved in the process of Ni allergy. Here, we examined the role of histamine in Ni allergy using a murine model previously established by us. Mice were sensitized to Ni by intraperitoneal injection of a NiCl2 -lipopolysaccharide (LPS) mixture. Ten days later, allergic inflammation was elicited by challenging ear-pinnas intradermally with NiCl2 . Then, ear-swelling was measured. Pyrilamine (histamine H1-receptor antagonist) or cromoglicate (mast cell stabilizer) was intravenously injected 1 h before the sensitization or the challenge. In cell-transfer experiments, spleen cells from Ni-sensitized donor mice were intravenously transferred into non-sensitized recipient mice. In both sensitized and non-sensitized mice, 1 mm or more NiCl2 (injected into ear-pinnas) induced transient non-allergic inflammation (Ni-TI) with accompanying mast cell degranulation. LPS did not affect the magnitude of this Ni-TI. Pyrilamine and cromoglicate reduced either the Ni-TI or the ensuing allergic inflammation when administered before Ni-TI (at either the sensitization or elicitation step), but not if administered when the Ni-TI had subsided. Experiments on HDC-KO and H1-receptor-KO mice, and also cell-transfer experiments using these mice, demonstrated histamine's involvement in both the sensitization and elicitation steps. These results suggest that mast cell histamine-mediated Ni-TI promotes subsequent allergic inflammatory responses to Ni, raising the possibility that control of Ni-TI by drugs may be effective at preventing or reducing Ni allergy.

Promotion of arthritis and allergy in mice by aminoglycoglycerophospholipid, a membrane antigen specific to Mycoplasma fermentans

Mycoplasmas, which lack a cell wall and are the smallest self-replicating bacteria, have been linked to some chronic diseases, such as AIDS, rheumatoid arthritis (RA), and oncogenic transformation of cells. Their membrane components (lipoproteins and glycolipids) have been identified as possible causative factors in such diseases. Glycoglycerophospholipid (GGPL)-III, a unique phosphocholine-containing aminoglycoglycerophospholipid, is a major specific antigen of Mycoplasma fermentans, and has been detected in 38% of RA patients. Unlike those of lipoproteins, which induce inflammation via Toll-like receptor 2 (TLR2), the pathologic effects of GGPL-III are poorly understood. RA and metal allergies are chronic inflammatory diseases in which autoantigens have been implicated. Here, we examined the effects of chemically synthesized GGPL-III in murine arthritis and allergy models. GGPL-III alone exhibited little inflammatory effect, but promoted both collagen-induced arthritis and nickel (Ni) allergy, although less powerfully than Escherichia coli lipopolysaccharide. The augmenting effect of GGPL-III on Ni allergy was present in mice deficient in either T cells or active TLR4, but it was markedly weaker in mice deficient in macrophages, interleukin-1, or the histamine-forming enzyme histidine decarboxylase than in their control strains. These results suggest that GGPL-III may play roles in some types of chronic diseases via the innate immune system.

Lipopolysaccharide promotes and augments metal allergies in mice, dependent on innate immunity and histidine decarboxylase

BACKGROUND

Few adequate murine models exist for metal allergies, it being especially difficult to induce Ni allergy in mice.

OBJECTIVE

We examined the effect of lipopolysaccharide (LPS) on allergies to Ni and other metals in mice.

METHODS

Ten days after sensitization with a metal salt and LPS, the ears were challenged with the same metal salt.

RESULTS

LPS+NiCl(2) (1 mM) was effective at sensitizing mice to Ni, LPS being effective at very low concentrations whether injected intradermally or intraperitoneally. The ear-swelling response to Ni was more severe and more rapid in C57BL/6 mice than in BALB/c mice. In mast-cell-deficient mice, TNF-alpha-deficient mice, and interestingly even in nude (T cell deficient) mice, NiCl(2)+LPS induced a Ni allergy similar in degree to that in the respective control mice, but it induced Ni allergy only weakly in TLR4-mutant mice, macrophage-depleted mice, and IL-1-deficient mice. The activity of the histamine-forming enzyme histidine decarboxylase (HDC) in the ears increased in parallel with ear swelling, and HDC-deficient mice were resistant to ear swelling. Challenge with NiCl(2)+LPS augmented ear swelling (vs. NiCl(2) alone). LPS induced effective sensitization to other metals (Cr, Co, Pd, or Ag).

CONCLUSIONS

These results indicate that in mice, LPS is a very important inducer of metal allergies, and potently promotes them (dependent on both innate immunity and HDC induction in cells other than mast cells). We discussed the idea that the bacterial environment is important for the establishment of metal allergies and for their provocation, and that the current thinking (including the contribution of T cells) should be reappraised in future studies.

Histidine decarboxylase-stimulating and inflammatory effects of alendronate in mice: Involvement of mevalonate pathway, TNFα, macrophages, and T-cells

Nitrogen-containing bisphosphonates (NBPs) are powerful anti-bone-resorptive drugs, but they frequently induce various inflammatory side effects. Recent clinical applications have disclosed an unexpected new side effect, jaw-bone necrosis and exposure. In vitro studies suggest that the inflammatory effects of NBPs are due to Vgamma2Vdelta2 T-cells, stimulated directly and/or indirectly [the latter via isopentenylpyrophosphate (IPP) in the mevalonate pathway]. Rats and mice, however, lack Vgamma2Vdelta2 T-cells, yet NBPs still induce necrotic and inflammatory reactions. In mice, NBPs induce IL-1-dependent inflammatory reactions, such as inductions of histidine decarboxylase (HDC, the histamine-forming enzyme) in the liver, lung, spleen, and bone marrow, an increase in granulocytic cells in the peritoneal cavity, pleural exudation, and splenomegaly. Here, we examined the involvement of IPP, TNF, macrophages, and T-cells in the inflammatory actions of alendronate (a typical NBP) in mice. Various statins (mevalonate-synthesis inhibitors) suppressed the alendronate-induced HDC inductions, while mevalonate itself augmented such inductions. IPP injection also induced HDC. Like IL-1-deficient mice, TNF-deficient mice were resistant to alendronate-stimulated HDC induction. Alendronate-stimulated HDC inductions were significantly weaker in macrophage-depleted mice and in nude mice than in control mice. Similar, though generally less clear-cut, results were obtained when other alendronate-induced inflammatory reactions were examined. These results suggest that (i) inhibition of the mevalonate pathway causes and/or modifies at least some inflammatory actions of alendronate in mice, (ii) in addition to IL-1, TNF is also involved in the inflammatory actions of alendronate, and (iii) alendronate may act on a variety of cells, including macrophages and T-cells.

Involvement of MAP kinases in lipopolysaccharide-induced histamine production in RAW 264 cells

Roles of mitogen-activated protein (MAP) kinases in lipopolysaccharide (LPS)-induced production of histamine in the mouse macrophage-like cell line RAW 264 were analyzed. Incubation of RAW 264 cells in the presence of LPS increased histamine levels in the conditioned medium in a concentration- and time-dependent manner. The levels of histidine decarboxylase (HDC) mRNA and the 74-kDa HDC protein were also increased at 4 to 8 h and 8 to 12 h, respectively. LPS elicited the phosphorylation of p44/42 MAP kinase, p38 MAP kinase, and c-Jun N-terminal kinase (JNK). The MAP kinase-Erk kinase 1 inhibitor U0126 (0.1-10 microM) suppressed the LPS-induced phosphorylation of p44/42 MAP kinase, and inhibited the LPS-induced production of histamine and expression of the HDC mRNA and 74-kDa HDC protein in a concentration-dependent manner. The JNK inhibitor SP600125 (3-30 microM) suppressed the LPS-induced phosphorylation of c-Jun, and inhibited the LPS-induced production of histamine and expression of the HDC mRNA and 74-kDa protein in a concentration-dependent manner. Combined treatment with U0126 (0.3 microM) and SP600125 (10 microM) inhibited the LPS-induced production of histamine additively. The p38 MAP kinase inhibitor SB203580 (0.1-10 microM) partially inhibited the LPS-induced production of histamine. These findings suggest that LPS increases histamine production in RAW 264 cells by inducing the expression of the 74-kDa HDC protein, and that the LPS-induced expression of HDC is up-regulated at the transcriptional level by MAP kinases, especially p44 MAP kinase and JNK.

Histamine production via mast cell-independent induction of histidine decarboxylase in response to lipopolysaccharide and interleukin-1

Histamine modulates immune responses. There are at least two ways histamine might be supplied: one is its release from cells that pool pre-formed histamine and the other is its de novo formation via induction of histidine decarboxylase (HDC). Lipopolysaccharide (LPS) and the proinflammatory cytokine interleukin (IL)-1 induce a marked elevation of HDC activity in various tissues or organs. To examine the contribution of mast cells to HDC induction in mice given LPS or IL-1, we examined the effects of LPS and IL-1 on HDC activity and/or histamine content in various organs (liver, lung, spleen or bone marrow) in mast cell-deficient mice (W/Wv), their normal littermates (+/+) and BALB/c mice deficient in IL-1alpha, IL-1beta and tumor necrosis factor (TNF)-alpha (IL-1alpha beta/TNFalphaKO mice). In non-stimulated mice, the histamine in the lung and spleen was contained largely within mast cells. The LPS-stimulated increase in HDC activity in a given organ was similar between +/+ and W/W(v) mice, and between IL-1alpha beta/TNFalphaKO BALB/c and control BALB/c mice, and led to increases in histamine. In W/Wv and +/+ mice, IL-1alpha also elevated HDC activity. These results suggest that (i) in liver, lung and spleen, either the major cells supplying histamine via HDC induction in response to LPS and IL-1 are not mast cells, or mast cells are not a prerequisite for the induction of HDC; (ii) the cells in which HDC is induced by LPS and IL-1 are similar or identical in a given organ; and (iii) neither IL-1 nor TNF-alpha is a prerequisite for the induction of HDC by LPS.

[Induction of histidine decarboxylase in inflammation and immune responses]

Histamine is a classical, but still interesting inflammatory mediator. Many people have long believed that histamine is derived from mast cells or basophils alone. However, the histamine-forming enzyme, histidine decarboxylase (HDC), is induced in a variety of tissues in response (i) to gram-positive and gram-negative bacterial components (lipopolysaccharides, peptidoglycan, and enterotoxin A) and (ii) to various cytokines (IL-1, IL-3, IL-12, IL-18, TNF, G-CSF, and GM-CSF). HDC is induced even in mast-cell-deficient mice. The histamine newly formed via the induction of HDC is released immediately and may be involved in a variety of immune responses. Reviewing our work and that of Schayer and Kahlson, the pioneers in this field, lead us to the conclusion that nowadays we need to understand that histamine can be produced via the induction of HDC by a mechanism coupled with the cytokine network. We call this histamine "neohistamine", to distinguish it from the classical histamine derived from mast cells or basophils. Neohistamine is involved in physiological reactions, inflammation, immune responses and a variety of diseases such as periodontitis, muscle fatigue (or temporomandibular disorders), stress- or drug-induced gastric ulcers, rheumatoid arthritis, complications in diabetes, hepatitis, allograft rejection, allergic reactions, tumor growth, and inflammatory side effects of aminobisphosphonates.

Possible involvement of histamine in muscular fatigue in temporomandibular disorders: animal and human studies

As an approach to clarifying the molecular basis of pain and fatigue in muscles involved in temporomandibular disorders, we examined the activity of histidine decarboxylase (HDC), the enzyme which forms histamine, in the masseter muscles of mice. In the resting muscle, HDC activity was very low. Direct electrical stimulation of the muscle markedly elevated HDC activity. HDC activity rose within 3 hrs of the electrical stimulation, peaked at 6 to 8 hrs, and then gradually declined. Intraperitoneal injection of a small amount of interleukin-1 (IL-1) (from 1 to 10 microg/kg) produced a similar elevation of HDC activity in the masseter muscle. We also examined the effect of an antihistamine, chlorphenylamine (CP), on temporomandibular disorders in humans and compared it with that of an anti-inflammatory analgesic, flurbiprofen (FB). Two groups received one or the other of the drugs daily for 7 days, and they were asked about their signs and symptoms before and after the treatment. A positive evaluation of their treatment was made by 74% of the CP group, but by only 48% of the FB group. Although the effects of CP on the limitation of mouth-opening and on joint noise were negligible, about 50% of the CP group answered positively concerning the drug's effect on spontaneous pain or pain induced by chewing or mouth-opening. The positive evaluation for CP (50%) in relieving associated symptoms (headache or shoulder stiffness) was significantly greater than for FB (13%). FB showed effectiveness similar to but sometimes weaker than that of CP on several symptoms. On the basis of these and previous results and the known actions of histamine, we propose that the histamine newly formed following the induction of HDC activity, which is itself mediated by IL-1, may be involved in inducing pain and, possibly, stiffness in muscles in temporomandibular disorders.

Inhibition of inflammatory actions of aminobisphosphonates by dichloromethylene bisphosphonate, a non-aminobisphosphonate

1. When injected intraperitoneally into mice in doses larger than those used clinically, all the amino derivatives of bisphosphonates (aminoBPs) tested induce a variety of inflammatory reactions such as induction of histidine decarboxylase (HDC, the histamine-forming enzyme), hypertrophy of the spleen, atrophy of the thymus, hypoglycaemia, ascites and accumulation of exudate in the thorax, and an increase in the number of macrophages and/or granulocytes in the peritoneal cavity of blood. On the other hand, dichloromethylene bisphosphonate (Cl2MBP) a typical non-aminoBP, has no such inflammatory actions. In the present study, we found that this agent can suppress the inflammatory actions of aminoBPs. 2. Cl2MBP, when injected into mice before or after injection of 4-amino-1-hydroxybutylidene-1,1-bisphosphonic acid (AHBuBP; a typical aminoBP), inhibited the induction of HDC activity by AHBuBP in a dose- and time-dependent manner. The increase in HDC activity induced by AHBuBP was largely suppressed by the injection of an equimolar dose of Cl2MBP. Cl2MBP also inhibited other AHBuBP-induced inflammatory reactions, as well as the inflammatory actions of two other aminoBPs. However, Cl2MBP did not inhibit the increase in HDC activity induced by lipopolysaccharide (LPS). 3. We have previously reported that AHBuBP augments the elevation of HDC activity and the production of interleukin-1beta (IL-1beta) that are induced by LPS. These actions of AHBuBP were also inhibited by Cl2MBP. 4. Based on these results and reported actions of bisphosphonates, the mechanisms underlying the contrasting effects of aminoBPs and Cl2MBP, a non-aminoBP are discussed. The results suggest that combined administration of Cl2MBP and an aminoBP in patients might be a useful way of suppressing the inflammatory side effects of aminoBPs.

Induction by interleukin-1, tumor necrosis factor and lipopolysaccharides of histidine decarboxylase in the stomach and prolonged accumulation of gastric acid

1. Injection of interleukin-1 (IL-1) into pylorus-ligated rats has been shown strongly to inhibit gastric secretion. However, in the present study, we found that an intraperitoneal injection of IL-1 into intact (non-pylorus-ligated) fasted mice rapidly (within 30 min) induced an accumulation of gastric acid ('early response'). When the dose of IL-1 was larger, the accumulation lasted for a longer period. 2. Injection of IL-1 also caused a later elevation of the activity of histidine decarboxylase (HDC), the histamine-forming enzyme, in the stomach ('later response'). 3. Cimetidine, an antagonist of histamine H2-receptors, suppressed the accumulation of gastric acid in both the early and later periods. An irreversible inhibitor of HDC, alpha-fluoromethylhistidine, partially inhibited the accumulation in the later period. 4. IL-1, when injected 1 h after feeding in mice fasted overnight, markedly retarded gastric emptying. 5. Tumour necrosis factor (TNF) and lipopolysaccharide (LPS) or endotoxin from E. coli both had IL-1-like effects on the stomach, and their effects are presumably mediated by IL-1. 6. These results support the idea that an inhibition of gastric emptying and an elevation of HDC activity in the stomach may explain the findings that a long-lasting accumulation of gastric acid is induced by IL-1 despite its potent inhibition of gastric acid secretion. 7. On the basis of these results, and in the light of the known actions of histamine, the possible roles of IL-1 in gastric inflammation and ulceration are discussed.

Induction by interleukin-1 (IL-1) of the mRNA of histidine decarboxylase, the histamine-forming enzyme, in the lung of mice in vivo and the effect of actinomycin D

It is known that the activity of histidine decarboxylase (HDC), the histamine-forming enzyme, is induced in response to various stimuli. However, it has repeatedly been reported that actinomycin D (Act D), a typical inhibitor of RNA synthesis, is either ineffective, or actually potentiates induction of this enzyme. Thus, it has been suggested that the induction of HDC may not require the formation of mRNA, i.e. that pre-formed, long-lived mRNA molecules may be responsible for the induction. In the present study, we examined the effects of interleukin-1alpha (IL-1alpha) on the amount of HDC mRNA present during the induction of HDC activity. In mice injected with IL-1alpha, HDC mRNA increased in the lung, spleen and stomach, but was hardly detectable in these tissues in control (saline-injected) mice. In the lung, the time course of the rise and fall in HDC mRNA was shorter than that of the rise and fall in HDC activity. In the present study, actinomycin D (Act D) did not inhibit the increase in HDC mRNA induced by IL-1alpha; in fact, it potentiated the elevation of both HDC mRNA and HDC activity. These results suggest that IL-1alpha induces HDC activity or its enzyme protein through the formation of short-lived HDC mRNA molecules. This is the first demonstration that Act D can enhance an increase in HDC mRNA: this potentiating, rather than inhibiting, effect is discussed.

Effects of macrophage depletion on the induction of histidine decarboxylase by lipopolysaccharide, interleukin 1 and tumour necrosis factor

1. Our previous work has shown that injection into mice of lipopolysaccharide (LPS) and the cytokines interleukin 1 (IL-1) and tumour necrosis factor (TNF) induces histidine decarboxylase (HDC), the enzyme forming histamine, in various tissues such as liver, lung, spleen and bone marrow, but not in the blood. The induction of HDC also occurs in nude mice and mast cell-deficient mice. On the other hand, haematopoietic cytokines such as IL-3, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) only induce HDC in the haematopoietic organs, i.e. bone marrow and spleen. In the present study, the effect of macrophage depletion on the induction of HDC was examined. 2. On day 1 after a single intravenous injection of a macrophage depletor (liposomes encapsulating dichloromethylene diphosphonate, which is toxic when ingested into macrophages), macrophages were almost completely depleted in the liver and reduced by about 50% in the spleen and bone marrow, but not significantly affected in the lung. On day 3, the degrees of the depletion were similar to those of day 1. In the spleen, macrophages were depleted in the red pulp, and there was a structural destruction. 3. In macrophage-depleted mice, the induction of HDC by LPS, IL-1 alpha or TNF-alpha was not impaired in the liver, and was potentiated in the lung and bone marrow. The induction of HDC was decreased only in the spleen at day 3. 4. HDC was not induced by LPS in the spleen of the adult rat, which is correspondingly inactive in haematopoiesis.5 These results indicate that the major cells in which HDC activity is induced in response to LPS, IL-1 and TNF are not circulating granulocytes, circulating monocytes, T cells derived from thymus, mast cells or phagocytic macrophages. Based on these results, we discuss the possibility that the major cells in which HDC was induced in non-haematopoietic and haematopoietic organs were endothelial cells and haematopoietic precursor cells respectively.

Stimulation of the synthesis of histamine and putrescine in mice by a peptidoglycan of gram-positive bacteria

To clarify the base of in vivo biological activities of peptidoglycans of Gram-positive bacteria, the effects of a polysaccharide peptide of Staphylococcus epidermidis peptidoglycan (SEPS) on the synthesis of histamine and putrescine in BALB/c mice were examined and compared with those of a lipopolysaccharide (LPS or endotoxin) of Gram-negative bacteria. Within a few hours after its injection into BALB/c mice, SEPS induced histidine decarboxylase (HDC), the enzyme forming histamine, in the liver, lung, spleen and bone marrow, and ornithine decarboxylase (ODC), the enzyme forming putrescine, in the tissues except for the lung. SEPS induced HDC activity even in mast cell-deficient mice and in nude mice. These effects of SEPS were essentially the same as those of LPS. However, the dosage of SEPS capable of inducing HDC and ODC was much higher (100 to 1,000 times) than that of LPS. We have reported that C3H/HeN mice are resistant to SEPS in producing acute arthritis, and their productions of IL-1 and prostaglandin E2 are less than BALB/c mice sensitive to producing acute arthritis. In the present study, it was also found that C3H/HeN mice were markedly resistant to SEPS in inducing HDC activity.

Active translocation of platelets into sinusoidal and Disse spaces in the liver in response to lipopolysaccharides, interleukin-1 and tumor necrosis factor

1. Injection of lipopolysaccharides (LPS) or endotoxin into mice and rats induces a prolonged increase in serotonin (5-hydroxytryptamine: 5HT), predominantly in the liver. 2. The 5HT increase reflects the accumulation of platelets in the sinusoidal and perisinusoidal Disse spaces (spaces between endothelial cells and hepatocytes) in the liver. 3. Most of the platelets which accumulated in these spaces still retained their intact structure and a large amount of 5HT. 4. Interleukin-1 and/or tumor necrosis factor also induce the platelet response. 5. Kupffer's cells play a key role in this platelet response. 6. Anti-platelet drugs currently used, except for anti-inflammatory steroids, were ineffective in preventing the platelet response. 7. This platelet response is different from the well known platelet aggregation. 8. The possible involvement of this platelet response in insulin-independent hypoglycaemia, disseminated intravascular coagulation, septic shock, hepatitis, Shwartzman type reactions or self-defense mechanisms is discussed.

Histamine as an intracellular messenger in human platelets

The results of investigations in platelets provide evidence for an intracellular messenger role for histamine. Studies of neutrophils and of cellular proliferation suggest that there may be a wider role for histamine as an intracellular messenger modulating activation processes in cells.

Ornithine and histidine decarboxylase activities in mice sensitized to endotoxin, interleukin-1 or tumour necrosis factor by D-galactosamine

1. An injection of D-galactosamine (GalN) into mice together with a lipopolysaccharide (LPS or endotoxin), interleukin-1 (IL-1) or tumour necrosis factor (TNF), sensitized the mice and induced fulminant hepatitis with severe congestion resulting in rapid death. Since LPS and these cytokines induce ornithine decarboxylase (ODC) and histidine decarboxylase (HDC) in the liver and spleen of mice, the effects of GalN on the induction of ODC and HDC in these organs were examined. 2. The induction of ODC by LPS, IL-1 or TNF was suppressed by GalN in the liver, and this suppression preceded the hepatic congestion. There was good agreement between the degree of hepatic congestion and the suppression of ODC induction by various amounts of GalN. The induction of ODC in the spleen was suppressed only at the highest dose of GalN examined. 3. GalN is known to deplete uridine 5'-triphosphate (UTP), resulting in the suppression of RNA and protein synthesis. An injection of uridine, the precursor of UTP, diminished the GalN-induced suppression of ODC induction by LPS and prevented the hepatic congestion and death. 4. LPS-pretreatment before injection of LPS plus GalN prevented the suppression of ODC activity and prevented the hepatic congestion and death. 5. An injection of putrescine, the product of ODC, prolonged survival time and delayed the development of hepatic congestion. However, injection of an ODC inhibitor into the mice given LPS did not produce hepatic congestion. 6. The induction of HDC in the liver by LPS, IL-1 or TNF was not suppressed by GalN and, at high doses, the response to LPS was enhanced. An inhibitor of HDC neither prevented the hepatic congestion nor enhanced the protective effect of putrescine.7. Although GalN in combination with IL-la induced a markedly higher HDC activity than was observed when it was combined with TNFa, and suppressed the induction of ODC, the former combination at the doses used did not produce hepatic congestion or death. However, the sensitization to TNFa by GalN was markedly potentiated by IL-la.8. These results suggest that suppression of the induction of ODC by GalN may be one cause of the sensitization to LPS, IL-1 or TNF, and that the induction of HDC, i.e. histamine formation, may not be involved in this sensitization.9. These results are consistent with the hypothesis that both IL-1 and TNF are involved in the sensitization to LPS.

GM-CSF and G-CSF stimulate the synthesis of histamine and putrescine in the hematopoietic organs in vivo

Histamine and putrescine (a precursor of polyamines) are formed by histidine decarboxylase (HDC) and ornithine decarboxylase (ODC), respectively. Within a few hours after injection of a lipopolysaccharide (LPS) into mice, HDC is induced in the liver, spleen, lung and bone marrow, and ODC is induced in the liver, spleen and bone marrow. Since LPS is known to stimulate the production of various cytokines, the abilities of various cytokines to induce HDC and ODC in the tissues of mice were examined. IL-2, IL-6, IL-8, IFN gamma and M-CSF were ineffective. IL-1 alpha, IL-1 beta, TNF alpha and TNF beta induced HDC and ODC, as does LPS. On the other hand, GM-CSF and G-CSF induced HDC and ODC only in the spleen and bone marrow within a few hours after their injection. These results suggest that, in addition to their roles in inflammation or immune responses, HDC and ODC are also involved in an early stage of hematopoiesis.

The effect of lipopolysaccharide, interleukin-1 and tumour necrosis factor on the hepatic accumulation of 5-hydroxytryptamine and platelets in the mouse

1. Injection of lipopolysaccharide (LPS; 0.5-500 microgram kg-1) into mice induced a dose-dependent, slowly developing increase in hepatic content of 5-hydroxytryptamine (5-HT). This sustained increase could not be attributed to an LPS-induced alteration of the pharmacokinetic handling of 5-HT by stimulation of its uptake or inhibition of its degradation. 2. Regional differences were apparent in the tissue content of histamine and 5-HT between mast cell-deficient (W/Wv) and normal (+/+) mice. LPS administration (0.5 mg kg-1) gave comparable increases in the hepatic level of 5-HT in mast cell-deficient and normal mice. 3. Reserpine pretreatment (1 mg kg-1) selectively reduced 5-HT levels in the blood, spleen, liver, brain and lung of normal mice. Prior treatment with this agent also abolished the LPS (0.5 mg kg-1)-induced hepatic accumulation of 5-HT. 4. Accumulation of 5-HT in the liver by LPS (0.1 mg kg-1) was temporally associated with both a fall in the levels of circulating platelets, and a reduction in the concentration of 5-HT in the blood. The LPS dose-dependent (0.5-500 micrograms kg-1) increase in hepatic 5-HT content was associated with a similar dose-dependent reduction in the circulating levels of 5-HT. 5. Interleukin-1, alpha and beta (10 micrograms kg-1) and tumour necrosis factor alpha (TNF alpha) (1 mg kg-1) significantly enhanced the accumulation of 5-HT within the liver. Administration of TNF alpha (10 micrograms kg-1) potentiated the increase in hepatic 5-HT content seen with IL-1 beta (10 micrograms kg-1). 6. Electron microscopy revealed numerous platelets in the sinusoidal and perisinusoidal Disse spaces within the liver, in animals pretreated with LPS (0.1 mg kg '). The platelets retained their intact structure and showed no evidence of degranulation. 7. These data suggest that the LPS and cytokine-induced mobilization of 5-HT in the liver is associated with the hepatic translocation of platelets. This migration appears to be independent of platelet aggregation.

Induction of histidine and ornithine decarboxylase activities in mouse tissues by recombinant interleukin-1 and tumor necrosis factor

The injection of recombinant interleukin-1 (IL-1) into mice induced histidine decarboxylase (HDC) activity in the bone marrow, spleen, lung and liver and ornithine decarboxylase (ODC) activity in the spleen and liver. The ability of IL-1 to induce these responses was the most potent of the various cytokines tested. The induction of these responses by IL-1 seemed to be more rapid than that produced by a lipopolysaccharide. The potency of IL-1 alpha to induce both HDC and ODC activities was similar to that of IL-1 beta, and their combination did not potentiate the induction of these responses. In contrast, although the ability of recombinant tumor necrosis factor-alpha (TNF alpha) to induce these responses was less potent than that of IL-1 alpha or IL-1 beta, the combination of TNF alpha and IL-1 beta produced higher HDC and ODC activities in some tissues tested than those induced by the combination of IL-1 alpha and IL-1 beta. These results suggest that the syntheses of histamine and putrescine are regulated by IL-1 and/or TNF alpha in inflammatory or immune responses. Through these experiments, it was noticed that, in spite of a marked induction of HDC activity in the bone marrow, there was no detectable induction of ODC activity in this tissue. The meaning of HDC induction in the bone marrow is discussed.

Significance of increased secretion of glucocorticoids in mice and rats injected with bacterial endotoxin

Injection of mice or rats with lipopolysaccharide (LPS) is associated with an increased secretion of glucocorticoids. The high level of mortality following injection of LPS that is noted in adrenalectomized rats can be reversed by dexamethasone or corticosterone. That histamine may be an endogenous mediator of the release of corticosterone caused by LPS is suggested by an attenuation of this corticosterone response by promethazine, an H1 antihistamine. Additional support that LPS-dependent glucocorticoid secretion is mediated, in part, by histamine, is suggested by spleen cell transfer studies revealing differences in the induction of histidine decarboxylase (HDC) synthesis and corticosterone release by the C3H/HeN and C3H/HeJ strains of mice that are differentially sensitive to LPS effects. These and other data on increased levels of histamine and HDC during mitogen-induced lymphocyte blastogenesis, as well as experiments revealing immunomodulatory effects of histamine and histamine agonists and antagonists on lymphocyte blastogenesis, are consistent with the hypothesis that following infection with gram-negative bacteria, the histamine-induced increase in glucocorticoid secretion results in inhibition of HDC in splenocytes, a concomitant attenuation of histamine production, and a resulting return to immune homeostasis.

LPS-caused secretion of corticosterone is mediated by histamine through histidine decarboxylase

Escherichia coli lipopolysaccharide (LPS) induced strong time- and dose-dependent secretion of corticosterone (CS) in C3H/HeN mice. In contrast, C3H/HeJ mice were very insensitive to LPS; 100,000 times more LPS was required with C3H/HeJ mice for producing a similar degree of CS secretion as that of C3H/HeN mice. However, C3H/HeJ mice could efficiently respond to other types of stressors, immobilization stress or injection of histamine, a possible mediator of LPS-induced CS secretion (28), leading to a striking increase in the serum levels of CS. Adoptive transfer of spleen cells from C3H/HeN mice converted x-irradiated C3H/HeJ mice to the donor phenotype. Injection of LPS produced a large increase in the activity of histidine decarboxylase (EC 4.1.1.22) in the spleen, lung, and liver of C3H/HeN mice, whereas C3H/HeJ mice were far less responsive. Transfer of spleen cells from the C3H/HeN mice made C3H/HeJ mice sensitive to LPS, leading to an increase in histidine decarboxylase activity in the spleen. There was a statistically significant relationship between the activity of splenic histidine decarboxylase and the serum levels of CS. These results suggest that the LPS-induced secretion of CS is mediated by histamine through induction of histidine decarboxylase in the spleen, lung, and liver. This may be significant in relation to the host-defense mechanism against endotoxemia.

Macrophages can produce factors capable of inducing histidine decarboxylase, a histamine-forming enzyme, in vivo in the liver, spleen, and lung of mice

Injection into mice of culture supernatant of P388D1 cells, a murine macrophage cell line, produced a rapid increase in histidine decarboxylase (HDC) activities in the liver, spleen, and lung. Factors in the culture supernatant capable of inducing the HDC elevation were purified by gel filtration and chromatofocusing. Throughout these procedures, the HDC-inducing activity accompanied the mitogenic activity for thymocytes or interleukin 1 (IL-1) activity. Although, because of low purity of the preparations, it is not confirmed whether the HDC inducer is IL-1 itself or not, the present results indicate that P388D1 cells can produce a factor(s) capable of inducing HDC in mouse tissues in vivo. After the injection of the HDC-inducing factor into mice, HDC induction in the tissues occurred within 2 hr and peaked at 2 to 4 hr, resulting in the increase in histamine levels 1 to 10 nmol/g tissue. These results provide important information concerning the source of endogenous histamine that might be involved in inflammatory reactions in delayed-hypersensitivity reactions or in the immune regulation observed in many in vitro systems.

Effects of alpha-fluoromethylhistidine on increase in histidine decarboxylase activity of maternal mouse kidney observed during late pregnancy and evidence for its non-mast cell origin by using estrogen and W/WV mice

The increase of histidine decarboxylase (HDC) activity during late pregnancy in the whole bodies of fetal mice and the kidneys of their mothers were almost completely inhibited by i.p. administration of 25 mg/kg of alpha-fluoromethylhistidine (alpha-FMH), a suicide inhibitor of HDC, starting on day 13 of pregnancy. The increase of HDC in fetal mice was previously shown to be in mast cells [T. Watanabe et al., Proc. Natl. Acad. Sci. U.S.A. 78, 4209-4212 (1981)]. The increase of HDC in maternal kidneys was examined by using estrogen and W/WV mice, which were devoid of mast cells and infertile. Treatment of castrated mice with 17-beta-estradiol increased the HDC activity of the kidney, and this increase was antagonized by concomitant treatment with clomiphene, an antiestrogen, confirming that the increase is mediated through an estrogen receptor. HDC activity in the kidney of W/WV mice was also increased by estradiol treatment, indicating that HDC activity was associated with non-mast cells.

Induction of histidine decarboxylase activity in the spleen of mice treated with staphylococcal enterotoxin A and demonstration of its non-mast cell origin

Histidine decarboxylase (HDC) activity increased 13-, 7-, and 2-fold in the spleen, lung and liver, respectively, but not in other tissues of C57BL/6 mice injected i.v. with 50 micrograms/kg of Staphylococcal enterotoxin A (SEA). But even in the spleen, increase in the histamine level was only 1.5 times that of untreated mice. In genetically mast cell-deficient WBB6F1 - W/Wv mice HDC activity in the spleen increased to the same extent as in wild type WBB6F1 - +/+ mice on SEA treatment, but the histamine level in the spleen also increased 20-fold, whereas it increased only 1.4-fold in +/+ mice. These results suggest that the increases in HDC and histamine resulted from interaction of SEA with non-mast cells in tissues.

Interleukin 1-like factors can accumulate 5-hydroxytryptamine in the liver of mice and can induce hypoglycaemia

After the injection into mice of culture medium of P388D1 cells, a murine macrophage cell line, 5-hydroxytryptamine accumulated in the liver and blood glucose declined. The factors capable of inducing these responses were purified by gel filtration and chromatofocusing. With these procedures, the activity to induce the increase in 5-hydroxytryptamine in the liver accompanied the activity to induce hypoglycaemia. Moreover, through the purification, the factors were found in the fraction of interleukin 1, a lymphocyte-activating factor. These results suggest that the factors capable of inducing the increase in 5-hydroxytryptamine and hypoglycaemia are likely to be interleukin 1 molecules or molecules closely related to interleukin 1. The present and previous findings together with those in the literature support the idea that the increase in 5-hydroxytryptamine in the liver might be a cause of hypoglycaemia. These findings may provide new and important information about the roles of macrophages in inflammation or in immune responses.

Lethal effect of neutral mannan fraction of bakers' yeast in mice

A simple polysaccharide, the neutral mannan from Saccharomyces cerevisiae wild type strain (WNM) was found to kill ddY strain mice by intravenous administration, showing a LD50 value of 12.2 mg/kg. On the other hand, the acidic mannan fraction from the same yeast containing phosphate (WAM025), and chemically phosphorylated WNM (WNM-P) were practically non-toxic. Concerning the relationship between chemical structure and lethal effect of these mannans, it was demonstrated that a mannan possessing a highly branched structure exhibited stronger lethality than those with less branched structures. Against C3H/HeJ strain mice with no responsiveness to lipopolysaccharide, the LD50 value of WNM was as high as 75 mg/kg. Pretreatment with 500 mg/kg of D-mannose, N-acetyl-D-glucosamine, D-galactose, and L-fucose prevented mice from the lethal effects of WNM. However, WNM (LD100) did not show any lethal effect in mice for 2 to 12 hr after treatment with dexamethasone, an anti-inflammatory steroid.