Localization of calcitonin gene-related peptide in human esophageal Langerhans cells

Calcitonin gene-related peptide: key regulator of cutaneous immunity

Calcitonin gene-related peptide (CGRP) has been viewed as a neuropeptide and vasodilator. However, CGRP is more appropriately thought of as a pleiotropic signalling molecule. Indeed, CGRP has key regulatory functions on immune and inflammatory processes within the skin. CGRP-containing nerves are intimately associated with epidermal Langerhans cells (LCs), and CGRP has profound regulatory effects on Langerhans cell antigen-presenting capability. When LCs are exposed to CGRP in vitro, their ability to present antigen for in vivo priming of naïve mice or elicitation of delayed-type hypersensitivity is inhibited in at least some situations. Administration of CGRP intradermally inhibits acquisition of immunity to Th1-dominant haptens applied to the injected site while augmenting immunity to Th2-dominant haptens, although the cellular targets of activity in these experiments remain unclear. Although CGRP can be a pro-inflammatory agent, several studies have demonstrated that administration of CGRP can inhibit the elicitation of inflammation by inflammatory stimuli in vivo. In this regard, CGRP inhibits the release of certain chemokines by stimulated endothelial cells. This is likely to be physiologically relevant as cutaneous blood vessels are innervated by sensory nerves. Exciting new studies suggest a significant role for CGRP in the pathogenesis of psoriasis and, most strikingly, that CGRP inhibits the ability of LCs to transmit the human immunodeficiency virus 1 to T lymphocytes. A more complete understanding of the role of CGRP in the skin immune system may lead to new and novel approaches for the therapy of immune-mediated skin disorders.

Intestinal Langerhans cell histiocytosis-like lesion in an adult presented with diverticulitis: a reactive or neoplastic condition?

The involvement of the gut by Langerhans cell histiocytosis (LCH) is very rare in adults; however this is usually observed with a disseminated disease in children. We report a 75-year-old male patient who underwent right hemicolectomy for a complicated intestinal diverticular disease. The surgical specimen revealed LCH-like proliferative lesion associated with diverticulitis. The overall morphological and immunohistochemical findings are indistinguishable from LCH. Systemic scans and subsequently performed bone marrow biopsies were free of disease. Although the HUMARA clonality assay cannot be assessed, the lack of evidence of LCH progression or disease elsewhere in the whole body strongly supported the possibility of an atypical reactive phenomenon probably due to the underlying intestinal diverticular disease. Therefore, it is important to avoid diagnosing such a unifocal Langerhans cell proliferation as LCH in patients with underlying pathologies in the absence of systemic involvement. Therefore, without knowledge of clonal status of a unifocal Langerhans cell proliferation, we recommend using the terminology of LCH-like lesion.

HCl-induced inflammatory mediators in esophageal mucosa increase migration and production of H2O2 by peripheral blood leukocytes

Exposure of esophageal mucosa to hydrochloric acid (HCl) is a crucial factor in the pathogenesis of reflux disease. We examined supernatant of HCl-exposed rabbit mucosa for inflammatory mediators enhancing migration of leukocytes and production of H(2)O(2) as an indicator of leukocyte activation. A tubular segment of rabbit esophageal mucosa was tied at both ends to form a sac, which was filled with HCl-acidified Krebs buffer at pH 5 (or plain Krebs buffer as control) and kept oxygenated at 37 degrees C. The medium around the sac (supernatant) was collected after 3 h. Rabbit peripheral blood leukocytes (PBL) were isolated, and sac supernatant was used to investigate PBL migration and H(2)O(2) production. HCl-exposed esophageal mucosa released substance P (SP), CGRP, platelet-activating factor (PAF), and IL-8 into the supernatant. PBL migration increased in response to IL-8 or to supernatant of the HCl-filled mucosal sac. Supernatant-induced PBL migration was inhibited by IL-8 antibodies and by antagonists for PAF (CV3988) or neurokinin 1 (i.e., SP), but not by a CGRP antagonist. Supernatant of the HCl-filled mucosal sac increased H(2)O(2) release by PBL that was significantly reduced by CV3988 and by a SP antagonist but was not affected by IL-8 antibodies or by a CGRP antagonist. We conclude that IL-8, PAF, and SP are important inflammatory mediators released by esophageal mucosa in response to acid that promote PBL migration. In addition, PAF and SP induce production of H(2)O(2) by PBL. These findings provide a direct link between acid exposure and recruitment and activation of immune cells in esophageal mucosa.

Antimicrobial anxiety: the impact of stress on antimicrobial immunity

Leukocytes and epithelial cells are fundamental to antimicrobial immunity. Their antimicrobial responses are an evolutionarily conserved component of the innate immune system and are influenced by the host's response to external stimuli. The efficacy of host defense via antimicrobial responses derives from the ability of AMPs to rapidly identify and eradicate foreign microbes and activate proinflammatory pathways, and from the capacity of later innate and adaptive immune responses to amplify protection through distinct biochemical mechanisms. Recent advances in neuroimmunology have identified a direct link between the neuroendocrine and immune systems, where environmental stimuli are generally believed to promote a transient effect on the immune system in response to environmental challenges and are presumably brought back to baseline levels via neuroendocrine pathways. Stress is an environmental stimulus that flares from a variety of circumstances and has become engrained in human society. Small bouts of stress are believed to enhance the host's immune response; however, prolonged periods of stress can be detrimental through excess production of neuroendocrine-derived mediators that dampen immune responses to invasive pathogens. Elucidation of the mechanisms behind stress-induced immune modulation of antimicrobial responses will ultimately lead to the development of more effective therapeutic interventions for pathologic conditions. It is the intent of this review to broaden the existing paradigm of how stress-related molecules dampen immune responses through suppression of antimicrobial mechanisms, and to emphasize that bacteria can use these factors to enhance microbial pathogenesis during stress.

HCl-activated neural and epithelial vanilloid receptors (TRPV1) in cat esophageal mucosa

To test whether transient receptor potential channel vanilloid subfamily member-1 (TRPV1) mediates acid-induced inflammation in the esophagus, a tubular segment of esophageal mucosa was tied at both ends, forming a sac. The sac was filled with 0.01 N HCl (or Krebs buffer for control) and kept in oxygenated Krebs buffer at 37 degrees C. The medium around the sac (supernatant) was collected after 3 h. Supernatant of the HCl-filled sac abolished contraction of esophageal circular muscle strips in response to electric field stimulation. Contraction was similarly abolished by supernatant of mucosal sac filled with the TRPV1 agonist capsaicin (10(-6) M). These effects were reversed by the selective TRPV1 antagonist 5'-iodoresiniferatoxin (IRTX) and by the platelet-activating factor (PAF) receptor antagonist CV9388. Substance P and CGRP levels in mucosa and in supernatant increased in response to HCl, and these increases were abolished by IRTX and by tetrodotoxin (TTX) but not affected by CV9388, indicating that substance P and CGRP are neurally released and PAF independent. In contrast, the increase in PAF was blocked by IRTX but not by TTX. Presence of TRPV1 receptor was confirmed by RT-PCR and by Western blot analysis in whole mucosa and in esophageal epithelial cells enzymatically isolated and sorted by flow cytometry or immunoprecipitated with cytokeratin antibodies. In epithelial cells PAF increased in response to HCl, and the increase was abolished by IRTX. We conclude that HCl-induced activation of TRPV1 receptors in esophageal mucosa causes release of substance P and CGRP from neurons and release of PAF from epithelial cells.

Research progress of enteric nervous system in esophagus

The functions of esophageal peristalsis and contraction were regulated and controlled by both neural and humoral system at all levels. Esophageal function depends on coordination of all the effectors regulated by enteric nervous system (ENS). Esophageal neurons are generally divided into two groups: the excitatory neurons and the inhibitory neurons. They regulate the tone, peristalsis and contraction of esophagus by interaction of various neurotransmitters. This article reviews recent research advancement of ENS in esophagus.

Transient receptor potential vanilloid 1-mediated expression and secretion of endothelial cell-derived calcitonin gene-related peptide

Calcitonin gene-related peptide (CGRP), the principal transmitter in sensory nerves, could also be expressed in vascular endothelium. Transient receptor potential vanilloid 1(TRPV1), which modulates the synthesis and release of CGRP in sensory nerves, is also present in endothelial cells. The present study tested whether TRPV1 modulates the release and synthesis of CGRP in endothelial cells, and evaluated the protective effect of endothelial cell-derived CGRP. Human umbilical vein endothelial cells (HUVECs) were treated with capsaicin or hyperthermia. The level of CGRP mRNA was detected by RT-PCR, and protein level was measured by radioimmunoassay. Endothelial cell injury was induced by lysophosphatidylcholine, and evaluated by cell viability and lactate dehydrogenase activity. HUVECs expressed CGRP, both alpha- and beta-subtype. Capsaicin increased the level of CGRP in the culture medium, and up-regulated the expression of CGRP in endothelial cells. Hyperthermia also increased the level of CGRP mRNA. These effects were abolished by capsazepine, a competitive antagonist of TRPV1. Capsaicin significantly attenuated the endothelial cell damage induced by LPC, which was prevented and aggravated by capsazepine or CGRP(8-37,) antagonist of CGRP receptor. These results indicate that TRPV1 also regulates the expression and secretion of endothelial cell-derived CGRP, which affords protective effects on endothelial cells.

JNK-AP-1 pathway involved in interleukin-1beta-induced calcitonin gene-related peptide secretion in human type II alveolar epithelial cells

In a previous study, we found that calcitonin gene-related peptide (CGRP) could be induced by proinflammatory factor IL-1beta in A549 human type II alveolar (AEII) epithelial cells. We investigated the mechanism of IL-1beta-induced CGRP secretion and found that the PKC-p38 MAPK-NF-kappaB pathway was involved. In the present study, we found that IL-1beta stimulation induced c-Jun N-terminal kinase (JNK) activity within 15min in A549 cells. In investigating whether JNK was involved in IL-1beta-induced CGRP secretion, the JNK II inhibitor SP600125 was used and it significantly attenuated IL-1beta-induced CGRP secretion and c-Jun activity, which was elevated after IL-1beta stimulation from mRNA to protein level. EMSA results showed the activation of activator protein 1 (AP-1) after 2-h IL-1beta stimulation, and the JNK II inhibitor blocked c-Jun and AP-1 activity. Bioinformatic analysis showed five predicted AP-1 binding sites on the promoter of beta-CGRP; deletion analysis identified an AP-1 consensus site at -643bp relative to the initiation site, which mediates the beta-CGRP gene transcription in response to IL-1beta. These data suggest that besides the PKC-p38 MAPK-NF-kappaB pathway, the JNK-AP-1 pathway is involved in IL-1beta-induced CGRP secretion in A549 human type II alveolar epithelial cells, and a 643-bp site upstream of the transcription start site on the promoter of beta-CGRP is the AP-1 response element.

Immunomodulatory effects of ciprofloxacin in TNBS-induced colitis in mice

BACKGROUND

Crohn's exacerbation and pouchitis are commonly treated with ciprofloxacin and metronidazole. Few studies have shown an advantage of this regimen compared with other antibiotics. Most attributed the effect to its better antibacterial coverage. Others have shown an apparent anti-inflammatory effect of quinolones in several in vitro and in vivo models of inflammation other than inflammatory bowel diseases (IBD). Our objective was to test the hypothesis that ciprofloxacin may act as an anti-inflammatory agent rather than just an antibacterial drug using a model of chemical colitis.

METHODS

TNBS colitis was induced in BALB/c mice. The anti-inflammatory effect of ciprofloxacin compared with ceftazidime and dexamethasone was assessed.

RESULTS

Mice treated with ciprofloxacin (7.5 mg/kg or 15 mg/kg) had significant reductions in clinical signs, body weight loss, splenic and colonic weight increase compared with saline-treated and ceftazidime-treated mice. Histologic analysis showed mild inflammation in ciprofloxacin-treated mice with a mean score of 3.8 +/- 0.5 points compared with moderate colitis scored 7.8 +/- 1.3 and 9.5 +/- 0.5 points in saline and ceftazidime-treated mice, respectively. Analysis of cytokine levels in colon homogenates showed a significant decrease of IL-1beta, IL-8, and TNFalpha levels in ciprofloxacin-treated animals. Immunohistochemistry for NFkappaB showed strong positivity in saline and ceftazidime-treated mice in contrast to weak focal stain in ciprofloxacin- and dexamethasone-treated mice.

CONCLUSIONS

These findings imply that ciprofloxacin has an anti-inflammatory effect, rather than just an antibacterial one, making its use favorable in IBD patients.

Selective COX-2 inhibition reduces leukocyte sticking and improves the microcirculation in TNBS colitis

The role of cyclooxygenase-2 inhibitors in the course of experimental colitis is controversially discussed. The aim of this study was to evaluate leukocyte-endothelium interaction and colitis activity after applying the selective cyclooxygenase-2 inhibitor NS-398 in a rat trinitrobenzene sulfonic acid (TNBS) colitis model. The acute phase of TNBS colitis is characterized by a significant reduction of capillary blood flow, capillary density, diuresis, and weight and a significant increase in capillary permeability, leukocyte sticking, and hematocrit. Applying the selective cyclooxygenase-2 inhibitor NS-398 leads to a significant improvement of all microcirculatory parameters and clinical findings compared to the (untreated) colitis group. There are no histopathological differences between the individual colitis groups. Acute colitis is characterized by an extensive disturbance of microcirculation together with signs of systemic inflammatory response syndrome. These alterations are significantly improved by inhibiting cyclooxygenase-2. The results support the described correlation between cyclooxygenase activation and leukocyte-endothelium interaction. Moreover, they underscore the postulated relation between leukocyte-endothelium interaction and capillary blood flow.

Inhibition of RICK/Nuclear Factor-κB and p38 Signaling Attenuates the Inflammatory Response in a Murine Model of Crohn Disease

Nuclear factor-kappaB (NF-kappaB) is the main target of anti-inflammatory therapies in human chronic inflammatory bowel diseases (IBD), Crohn disease, and ulcerative colitis. This study investigates the molecular anti-inflammatory mechanisms of SB203580, an inhibitor of the mitogen-activated protein kinase p38. The murine trinitrobenzene sulfonic acid (TNBS)-induced colitis was used as an established model of human Crohn disease. Here we show that SB203580 improved the clinical condition, reduced intestinal inflammation, and suppressed mRNA levels of pro-inflammatory cytokines elevated upon induction of colitis. Besides p38 kinase activity, the "classical" IkappaB-dependent NF-kappaB pathway was strongly up-regulated during colitis induction, whereas the "alternative" was not. SB203580 treatment resulted in a drastic down-regulation of p38 and NF-kappaB activity. The molecular analysis of NF-kappaB activation revealed that Rip-like interacting caspase-like apoptosis-regulatory protein kinase (RICK), a key component of a pathway leading to NF-kappaB induction, is also strongly inhibited by SB203580. In contrast, SB203580 had no effect on the colitis-induced activation of other potential NF-kappaB-activating kinases such as protein kinase C (PKC), mixed lineage kinase 3, and the oncogene product Cot/TPL2. Thus, the inhibitory effect of SB203580 on NF-kappaB activation is to a large extent mediated by RICK inhibition. RICK is the effector kinase of the intracellular receptor of bacterial peptidoglycan NOD. Because bacterial products are suggested to be the key pathogenic agents triggering IBD, inhibition of the NOD/RICK pathway may serve as a novel target of future therapies in human IBD.

The significance of vasoactive intestinal peptide in immunomodulation

First identified by Said and Mutt some 30 years ago, the vasoactive intestinal peptide (VIP) was originally isolated as a vasodilator peptide. Subsequently, its biochemistry was elucidated, and within the 1st decade, their signature features as a neuropeptide became consolidated. It did not take long for these insights to permeate the field of immunology, out of which surprising new attributes for VIP were found in the last years. VIP is rapidly transforming into something more than a mere hormone. In evolving scientifically from a hormone to a novel agent for modifying immune function and possibly a cytokine-like molecule, VIP research has engaged many physiologists, molecular biologists, biochemists, endocrinologists, and pharmacologists and it is a paradigm to explore mutual interactions between neural and neuroendocrine links in health and disease. The aim of this review is firstly to update our knowledge of the cellular and molecular events relevant to VIP function on the immune system and secondly to gather together recent data that support its role as a type 2 cytokine. Recognition of the central functions VIP plays in cellular processes is focusing our attention on this "very important peptide" as exciting new candidates for therapeutic intervention and drug development.

Interleukin-1beta induces beta-calcitonin gene-related peptide secretion in human type II alveolar epithelial cells

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide mainly present in sensory nerve fibers, which is present in almost all organs, but it is also found in cultured rat type II alveolar epithelial cells (AEII). Our data have previously shown that CGRP may play an important role in inflammation as an immunomodulator. Proinflammatory factor IL-1beta induces CGRP release from neuron-derived sources. However, whether IL-1beta can induce CGRP secretion from a nonneural source, AEII cells, is not known. In the present study, we demonstrated that human AEII A549 cells expressed beta-CGRP, and IL-1beta (0.001-50 ng/ml) directly increased CGRP secretion from these cells in a time- and concentration-dependent manner. The mRNA level of beta-CGRP was also elevated by IL-1beta (1 ng/ml). In addition, we found that IL-1beta-induced CGRP production was mediated through the PKC-p38 mitogen-activated protein (MAP) kinase-NF-kappaB signaling pathway. Furthermore, IL-1beta-induced chemokines MCP-1 and IL-8 were partially inhibited by exogenous hCGRP (0.1-10 nM) and potentiated by hCGRP8-37 (0.1-10 nM), a CGRP1-receptor antagonist. In addition, the CGRP-inhibited chemokine effect was partially reduced by Rp-cAMP, a cAMP-PK inhibitor. These results suggest that AEII-derived CGRP may act in an autocrine/paracrine mode and play an important inhibitory role in the local area in lung inflammatory diseases.

Unsolved problems in the management of patients with gastro-oesophageal reflux disease

Gastro-oesophageal reflux disease is a common problem that brings large numbers of patients to physicians every day. It lowers the quality of life of affected individuals and exposes them to potentially dangerous complications. An increasing awareness exists among patients, doctors and authorities about the relevance of this pathological condition. Despite an improved understanding of many aspects of gastro-oesophageal reflux disease, clinical management of several cases is still unsatisfactory. Atypical cases with extra-oesophageal manifestations often defy diagnosis. Even typical symptoms are often misunderstood and considered to be part of the poorly defined area of dyspepsia by both patients and doctors. As a consequence, management remains uncertain for too many cases. If correctly diagnosed, gastro-oesophageal reflux disease can be efficaciously treated with proton pump inhibitors (PPIs). Although standard doses of PPIs can heal mucosal lesions and provide symptom relief in the vast majority of oesophagitis patients, non-oesophagitis symptomatic individuals and those with extra-oesophageal manifestations may fail to respond to similar regimens. Antireflux surgery is a possible alternative to PPI therapy, but it is hampered by complications in a substantial percentage of cases and by sporadic casualties even when performed by experienced surgeons. The high prevalence of gastro-oesophageal reflux disease in the general population and the relatively high management costs should prompt any doctor to seek the best possible therapeutic approach.

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) as modulators of both innate and adaptive immunity

The structurally related neuropeptides VIP and PACAP are released within the lymphoid organs following antigenic stimulation, and modulate the function of inflammatory cells through specific receptors. In activated macrophages, VIP and PACAP inhibit the production of pro-inflammatory agents (cytokines, chemokines, and nitric oxide), and stimulate the production of the anti-inflammatory cytokine IL-10. These events are mediated through the VIP/PACAP effects on de novo expression or nuclear translocation of several transcription factors, i.e., NFkappaB, CREB, c-Jun, JunB, and IRF-1. The in vivo administration of VIP/PACAP results in a similar pattern of cytokine and chemokine modulation, which presumably mediates the protective effect of VIP/PACAP in septic shock. In addition, VIP/PACAP reduce the expression of the co-stimulatory molecules B7.1/B7.2, and the subsequent stimulatory activity of macrophages for T-helper cells. In T-cells expressing specific VIP/PACAP receptors, VIP and PACAP inhibit the expression of FasL through effects on NFkappaB, NFAT, and Egr2/3. The reduction of FasL expression has several biological consequences: inhibition of antigen-induced cell death in CD4 T-cells, inhibition of the FasL-mediated cytotoxicity of CD8 and CD4 effectors against direct and bystander targets, and promotion of long-term memory Th2 cells, through a positive effect on the survival of Th2, but not Th1, effectors. The various biological effects of VIP and PACAP are discussed within the range of a general anti-inflammatory model.

Production and secretion of calcitonin gene-related peptide from human lymphocytes

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide, which is mainly present in primary sensory nerves. Although our previous study has shown that rat lymphocytes can synthesize beta-CGRP, there is no evidence demonstrating whether CGRP can be synthesized by human lymphocytes. In this study, the production of CGRP from human lymphocytes from spleen and blood were investigated by using CGRP-specific radioimmunoassay (RIA), and RNase protection assay (RPA). The results showed that human T lymphocyte mitogen, such as phytohemagglutinin (PHA), could time- and dose-dependently induce hCGRP secretion; rhIL-2 alone did not effect hCGRP secretion, but it could potentiate PHA-evoked hCGRP secretion from human spleen lymphocytes. RPA showed that alpha- and beta-CGRP mRNA were both constitutively expressed in unstimulated human peripheral blood mononuclear cells (PBMC). PHA could cause beta-hCGRP but not alpha-hCGRP mRNA increase in a time-dependent manner. In addition, hCGRP(8-37), a CGRP(1) receptor antagonist, enhanced PHA or human interleukin-2 (rhIL-2), induced the proliferation of splenocytes and PBMC. These results suggest that hCGRP is produced and secreted by human lymphocyte. Lymphocyte mitogen can induce the elevation of beta-CGRP synthesis and secretion. The lymphocyte-derived beta-CGRP may inhibit, at least in part, lymphocytes proliferation, which are then involved in the modulation of human T lymphocyte function in response to immune stimulation.

Lactoferrin reduces colitis in rats via modulation of the immune system and correction of cytokine imbalance

Natural immunomodulator lactoferrin is known to exert an anti-inflammatory effect. However, there have been no studies that examine the mode of action of lactoferrin in reducing intestinal damage. We investigated the effect of lactoferrin on a trinitrobenzenesulfonic acid (TNBS)-induced colitis model in rats. Bovine lactoferrin was given once daily through gavage, starting 3 days before (preventive mode) or just after TNBS administration (treatment mode) until death. The distal colon was removed to be examined. Colitis was attenuated by lactoferrin via both modes in a dose-dependent manner, as reflected by improvement in macroscopic and histological scores and myeloperoxidase activity. Lactoferrin caused significant induction of the anti-inflammatory cytokines interleukin (IL)-4 and IL-10, significant reductions in the proinflammatory cytokines tumor necrosis factor-alpha and IL-1beta, and downregulation of the nuclear factor-kappaB pathway. We concluded that lactoferrin exerts a protective effect against colitis in rats via modulation of the immune system and correction of cytokine imbalance. Lactoferrin has potential as a new therapeutic agent for inflammatory bowel disease.

Bone marrow-derived macrophages express functional CGRP receptors and respond to CGRP by increasing transcription of c-fos and IL-6 mRNA

Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide with inflammatory and immunoregulatory properties. CGRP inhibits IL-7 responses by B cell precursors by direct and indirect mechanisms. We recently found that CGRP induces IL-6 and TNF-alpha in long-term bone marrow cultures and that IL-6 and TNF-alpha also inhibit IL-7 responses. Because these are heterogeneous cultures, it was not clear which cells produced IL-6 and TNF-alpha. To determine whether bone marrow-derived macrophages (BMDM) were the source, we did studies to determine whether BMDMs express mRNAs for CGRP receptors and whether CGRP induces c-fos, IL-6, and TNF-alpha mRNA. We found that BMDMs express mRNAs for CRLR and RAMP1, the minimal components for CGRP receptors. CGRP also stimulated dose- and time-dependent increases in c-fos and IL-6. In contrast, CGRP did not induce TNF-alpha in BMDMs. These results suggest that BMDMs are a source of CGRP-induced IL-6 in bone marrow.

Inhibitory neuropeptide receptors on macrophages

The immune response, both in innate and adaptive immunity, is controlled at several levels, including signaling from the central nervous system. Neuropeptides released within the lymphoid organs modulate the immune response, either as stimulators or inhibitors. The subject of this review is the description of macrophage-expressed receptors of inhibitory neuropeptides. We describe the inhibitory effects on macrophage function for several neuropeptides, the receptors that mediate those activities, and the molecular mechanisms initiated by some of these receptors in terms of transduction pathways and transcriptional factors.

Induction and expression of beta-calcitonin gene-related peptide in rat T lymphocytes and its significance

Our previous data have shown that rat lymphocytes can synthesize calcitonin gene-related peptide (CGRP), a neuropeptide. In this study the type, characteristics, and functional role of lymphocyte-derived CGRP were investigated. The results showed that treatment with Con A (4 microg/ml) and recombinant human IL-2 (rhIL-2; 750 U/ml) for 3-5 days induced CGRP synthesis and secretion by lymphocytes from both thymus and mesenteric lymph nodes in a time-dependent manner. Stimulation of these cells with Con A (1-8 microg/ml) or rhIL-2 (94-1500 U/ml) for 5 days induced a significant increase in CGRP secretion in a concentration-dependent manner. The maximal secretion of CGRP with Con A by thymocytes was elevated from 104+/-11 to 381 +/- 44 pg/10(8) cells, and that by mesenteric lymph node lymphocytes was elevated from 83+/-10 to 349+/-25 pg/10(8) cells, respectively. The maximal CGRP secretion with rhIL-2 by thymocytes was elevated from 116+/-3 to 607+/-23 pg/10(8), and that by mesenteric lymph node lymphocytes was elevated from 117+/-9 to 704+/- 37 pg/10(8) cells, respectively. The nucleotide sequencing study showed that lymphoid cells expressed beta-CGRP cDNA only. The levels of beta-CGRP mRNA in mitogen-stimulated lymphocytes of both sources were also increased. However, LPS had no such effect on either source of cells. hCGRP(8-37) (2.0 microM), a CGRP(1) receptor antagonist, enhanced Con A-induced proliferation and IL-2 release of thymocytes by 41.3 and 35.8% over those induced by Con A alone, respectively. The data suggest that T lymphocyte mitogens can induce the production of endogenous beta-CGRP from T lymphocytes, which may partially inhibit the proliferation and IL-2 release of rat T lymphocyte under immune challenges.

Aberrant esophageal HLA-DR expression in a high percentage of patients with Crohn's disease

Esophageal histology is not well studied in patients with Crohn's disease (CD). We, therefore, analyzed the histologic and immunohistologic appearance of esophageal mucosa in CD. Biopsy specimens taken from the esophagus of 57 consecutive patients with known CD of the large and/or small bowel, of 200 Crohn's-free controls, of 15 cases with ulcerative colitis, and of 5 cases with viral esophagitis were evaluated. In controls, most patients had either HLA-DR negative esophageal epithelium or showed focal or diffuse basal staining. HLA-DR expression of all epithelial layers (transepithelial staining) was observed in only four (2%) control subjects, in one case with herpes esophagitis, but not in patients with ulcerative colitis. In contrast, transepithelial HLA-DR expression was found in 19 (33%) patients with CD (p < 0.0001). In CD patients, it was associated with a significantly increased epithelial content in T-cells (CD3+, TIA-1+, granzyme B+), B-cells (CD79a+), natural killer cells (CD57+), and macrophages (CD68+). There was no correlation with either histological findings elsewhere in the upper gastrointestinal tract or with laboratory findings, symptoms, CDAI, or medication. Transepithelial esophageal HLA-DR expression is common in CD. Immunohistochemistry may prove useful in supporting the histologic diagnosis of CD in staging procedures, for initial diagnosis as well as in doubtful cases.

Langerhans cells in the neuro-immuno-cutaneous system

Langerhans cells are epidermal antigen presenting cells. They are able to express some neuronal markers. They express many neuropeptide receptors. Neuropeptides are able to modulate Langerhans cell functions. Langerhans cells are closely connected with nerve fibers in the epidermis. Thus, Langerhans cells and the nervous system are anatomically and functionally associated. We suggest that they belong to a neuroimmunocutaneous system. The interactions between nervous and immune system are probably important in the pathophysiogeny of inflammatory dermatoses.

Histopathology of the enteric neuropathies. From silver staining to immunohistochemistry

The gut is abundantly supplied with neurons, extrinsic and intrinsic nerve fibers. Knowledge regarding the structure of the enteric nervous system derives principally from the classic silver-staining methods. Because silver stains do not provide information on the molecular constituents of neurons, these data only facilitate classification and may have diagnostic significance. Studies using histochemistry and immunohistochemistry are now completing the morphologic picture and laying the groundwork for the formulation of therapeutic strategies based upon demonstrable chemical defects in enteric disease.

An analysis of the role of skin Langerhans cells (LC) in the cytoplasmic processing of HIV-1 peptides after "peplotion" transepidermal transfer and HLA class I presentation to CD8+ CTLs--an approach to immunization of humans

Skin Langerhans cells (LC) are antigen-presenting cells capable of expressing MHC class I and class II molecules on the plasma membrane. This molecular activity was reviewed to combine the knowledge of peptide presentation by MHC and HLA class I and class II molecules to prime CD8+ cytotoxic T cells (CTLs) and CD4+ T helper cells, respectively. The possible utilization of the skin dendritic cells for the development of antiviral CTLs and antibodies by synthetic peptides modeled according to the motifs of peptides that naturally interact with the peptide binding grooves of the various HLA haplotypes is discussed and evaluated. It may be possible that the introduction of synthetic viral peptides with motifs to fit the HLA class I haplotypes of a human population to the skin dendritic cells will prime selectively the cellular or the humoral immune responses. This approach may provide a new vaccination technique that applies synthetic virus peptides as vaccines for the immunization of humans. The neuropeptide CGRP interacts with LC and modulates antigen presentation.

Regulation of Langerhans cell function by nerves containing calcitonin gene-related peptide

Several observations suggest interactions between the immune and nervous systems. Psoriasis and atopic dermatitis may worsen with anxiety and have been associated with anomalous neuropeptide regulation. Neurotransmitters affect lymphocyte function and lymphoid organs are innervated. Calcitonin gene-related peptide (CGRP) is a neuropeptide and vasodilator that modulates some macrophage functions, including antigen presentation in vitro. CGRP is associated with Langerhans cells (LC) in oesophageal mucosa, particularly during inflammation, is present in epidermal nerves and is associated with Merkel cells. We examined the ability of CGRP to modulate LC antigen-presenting function and asked if CGRP-containing nerves impinge on LC. We report here that CGRP-containing nerve fibres are intimately associated with LC in human epidermis and CGRP is found at the surface of some LC. In three functional assays CGRP inhibited LC antigen presentation. These findings indicate that CGRP may have immunomodulatory effects in vivo and suggest a locus of interaction between the nervous system and immunological function.