Bombesin-related peptides modulate interleukin-1 production by alveolar macrophages

Neuropeptides in asthma, chronic obstructive pulmonary disease and cystic fibrosis

The nervous system mediates key airway protective behaviors, including cough, mucus secretion, and airway smooth muscle contraction. Thus, its involvement and potential involvement in several airway diseases has become increasingly recognized. In the current review, we focus on the contribution of select neuropeptides in three distinct airway diseases: asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. We present data on some well-studied neuropeptides, as well as call attention to a few that have not received much consideration. Because mucus hypersecretion and mucus obstruction are common features of many airway diseases, we place special emphasis on the contribution of neuropeptides to mucus secretion. Finally, we highlight evidence implicating involvement of neuropeptides in mucus phenotypes in asthma, COPD and cystic fibrosis, as well as bring to light knowledge that is still lacking in the field.

Neuromedin: An insight into its types, receptors and therapeutic opportunities

Neuropeptides are small protein used by neurons in signal communications. Neuromedin U was the first neuropeptide discovered from the porcine spinal and showed its potent constricting activities on uterus hence was entitled with neuromedin U. Following neuromedin U another of its isoform was discovered neuromedin S which was observed in suprachiasmatic nucleus hence was entitled neuromedin S. Neuromedin K and neuromedin L are of kanassin class which belong to tachykinin family. Bombesin family consists of neuromedin B and neuromedin C. All these different neuromedins have various physiological roles like constrictive effects on the smooth muscles, control of blood pressure, pain sensations, hunger, bone metastasis and release and regulation of hormones. Over the years various newer physiological roles have been observed thus opening ways for various novel therapeutic treatments. This review aims to provide an overview of important different types of neuromedin, their receptors, signal transduction mechanism and implications for various diseases.

Insights into bombesin receptors and ligands: Highlighting recent advances

This following article is written for Prof. Abba Kastin's Festschrift, to add to the tribute to his important role in the advancement of the role of peptides in physiological, as well as pathophysiological processes. There have been many advances during the 35 years of his prominent role in the Peptide field, not only as editor of the journal Peptides, but also as a scientific investigator and editor of two volumes of the Handbook of Biological Active Peptides [146,147]. Similar to the advances with many different peptides, during this 35 year period, there have been much progress made in the understanding of the pharmacology, cell biology and the role of (bombesin) Bn receptors and their ligands in various disease states, since the original isolation of bombesin from skin of the European frog Bombina bombina in 1970 [76]. This paper will briefly review some of these advances over the time period of Prof. Kastin 35 years in the peptide field concentrating on the advances since 2007 when many of the results from earlier studies were summarized [128,129]. It is appropriate to do this because there have been 280 articles published in Peptides during this time on bombesin-related peptides and it accounts for almost 5% of all publications. Furthermore, 22 Bn publications we have been involved in have been published in either Peptides [14,39,55,58,81,92,93,119,152,216,225,226,231,280,302,309,355,361,362] or in Prof. Kastin's Handbook of Biological Active Peptides [137,138,331].

Oxygen, gastrin-releasing Peptide, and pediatric lung disease: life in the balance

Excessive oxygen (O2) can cause tissue injury, scarring, aging, and even death. Our laboratory is studying O2-sensing pulmonary neuroendocrine cells (PNECs) and the PNEC-derived product gastrin-releasing peptide (GRP). Reactive oxygen species (ROS) generated from exposure to hyperoxia, ozone, or ionizing radiation (RT) can induce PNEC degranulation and GRP secretion. PNEC degranulation is also induced by hypoxia, and effects of hypoxia are mediated by free radicals. We have determined that excessive GRP leads to lung injury with acute and chronic inflammation, leading to pulmonary fibrosis (PF), triggered via ROS exposure or by directly treating mice with exogenous GRP. In animal models, GRP-blockade abrogates lung injury, inflammation, and fibrosis. The optimal time frame for GRP-blockade and the key target cell types remain to be determined. The concept of GRP as a mediator of ROS-induced tissue damage represents a paradigm shift about how O2 can cause injury, inflammation, and fibrosis. The host PNEC response in vivo may depend on individual ROS sensing mechanisms and subsequent GRP secretion. Ongoing scientific and clinical investigations promise to further clarify the molecular pathways and clinical relevance of GRP in the pathogenesis of diverse pediatric lung diseases.

Gastrin-releasing peptide blockade as a broad-spectrum anti-inflammatory therapy for asthma

Gastrin-releasing peptide (GRP) is synthesized by pulmonary neuroendocrine cells in inflammatory lung diseases, such as bronchopulmonary dysplasia (BPD). Many BPD infants develop asthma, a serious disorder of intermittent airway obstruction. Despite extensive research, early mechanisms of asthma remain controversial. The incidence of asthma is growing, now affecting >300 million people worldwide. To test the hypothesis that GRP mediates asthma, we used two murine models: ozone exposure for air pollution-induced airway hyperreactivity (AHR), and ovalbumin (OVA)-induced allergic airway disease. BALB/c mice were given small molecule GRP blocking agent 77427, or GRP blocking antibody 2A11, before exposure to ozone or OVA challenge. In both models, GRP blockade abrogated AHR and bronchoalveolar lavage (BAL) macrophages and granulocytes, and decreased BAL cytokines implicated in asthma, including those typically derived from Th1 (e.g., IL-2, TNFα), Th2 (e.g., IL-5, IL-13), Th17 (IL-17), macrophages (e.g., MCP-1, IL-1), and neutrophils (KC = IL-8). Dexamethasone generally had smaller effects on all parameters. Macrophages, T cells, and neutrophils express GRP receptor (GRPR). GRP blockade diminished serine phosphorylation of GRPR with ozone or OVA. Thus, GRP mediates AHR and airway inflammation in mice, suggesting that GRP blockade is promising as a broad-spectrum therapeutic approach to treat and/or prevent asthma in humans.

Gastrin-releasing peptide links stressor to cancer progression

INTRODUCTION

Gastrin-releasing peptide (GRP) plays an important role in cancer growth and metastasis; however, the mechanisms of how GRP affects cancer progression are not well understood. Recent studies revealed that chronic stress is a major risk factor for cancer progression, and this effect may be mediated by GRP. In this review, we will discuss the mechanisms and implications of GRP linking stressor to cancer progression.

MATERIALS AND METHODS

We retrieved the studies of the relationship between GRP, stress and cancers through PubMed using systematic methods to search, select, and evaluate the findings.

RESULTS

The results suggested that GRP can mediate the effects of stress on cancers at systemic, tissue and cellular levels: Stress elicits the secretion of GRP in the brain and GRP in turn activates the stress response pathways resulting in an elevation of stress hormones and GRP in the plasma and tissues. GRP in synergy with stress hormones stimulates the growth and invasion of cancer cells by suppressing the anti-tumor immune function and directly activating the pro-proliferative and pro-migratory signaling pathways in cancer cells.

CONCLUSION

GRP is a multi-functional peptide, which acts as a stress mediator as well as a growth factor linking stressor to cancer progression. GRP and its high-affinity receptor are useful targets for the diagnosis and treatment of cancers.

Tumor-associated macrophages in clear cell renal cell carcinoma express both gastrin-releasing peptide and its receptor: a possible modulatory role of immune effectors cells

Purpose

Renal cell carcinomas (RCC) frequently express the gastrin-releasing peptide receptor (GRP-R). Gastrin-releasing peptide (GRP) stimulates tumor cell proliferation and neoangiogenesis. Tumor-associated macrophages (TAM) comprise an important cellular component of these tumors. We analyzed the GRP/GRP-R network in clear cell RCC (ccRCC) and non-clear cell RCC (non-ccRCC) with special regard to its expression by macrophages, tumor cells and microvessels.

Methods

Gastrin-releasing peptide and GRP-R expression in 17 ccRCC and 9 non-ccRCC were analyzed by RT-PCR, immunohistochemistry and double immunofluorescence staining.

Results

Tumor-associated macrophages expressed GRP and GRP receptor in ccRCC. Tumor cells and microvessels showed low to intermediate GRP-R expression in nearly all cases. In 12 ccRCC tumor epithelia also expressed low levels of GRP. Microvascular GRP expression was found in nine cases of ccRCC. For non-RCC, the expression of GRP and GRP receptor expression pattern was similar.

Conclusions

Tumor-associated macrophages are the main source of GRP in RCC. GRP receptor on TAM, tumor epithelia and microvessels might be a molecular base of a GRP/GRP receptor network, potentially acting as a paracrine/autocrine modulator of TAM recruitment, tumor growth and neoangiogenesis.

A case of pulmonary langerhans' cell histiocytosis mimicking hematogenous pulmonary metastases

A 31-year-old man presented with a dry cough and exertional dyspnea. The chest X-ray showed multiple nodular opacities throughout the entire lung field. Chest computed tomography (CT) revealed variable-sized nodules with a peribronchiolar or centrilobular distribution, some of which revealed thick-walled cavitary change. Based on the chest CT findings, it was initially assumed that metastatic lung nodules with hematogenous spread were present; therefore, we performed an open lung biopsy. On microscopic examination, several compact cellular interstitial infiltrates composed of Langerhans' cells, eosinophils, and lymphocytes were observed. Immunochemically, the Langerhans' cells showed strong cytoplasmic staining for S-100 protein. Based on these findings, the patient was diagnosed with Langerhans' cell histiocytosis of the lung. High-resolution CT of the chest is a useful, sensitive tool in the diagnosis of pulmonary Langerhans' cell histiocytosis (PLCH). A typical radiologic finding of PLCH is irregularly shaped cysts. The radiological finding in this case of nodular opacities throughout the lung fields only without cysts is rare in PLCH. We report a case of PLCH with atypical multiple nodules mimicking hematogenous metastatic lung nodules.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a poorly understood proliferative disease, with different patterns of clinical presentation. Currently it is classified according to the number and type of system involved and the degree of organ dysfunction. The aetiology of the disease remains uncertain, and in some cases the disease is polyclonal, suggesting a reactive condition. Many cytokines have been implicated in the pathogenesis of LCH. Different therapeutic approaches can be considered depending on the affected organ, including surgery, radiotherapy and chemotherapy. Long-term organ dysfunction may remain, despite disease control and/or eradication, making indefinite supportive treatment mandatory. Here we present a literature review on all of the aspects of the disease, treatment approaches and existing protocols, and finally an adult clinical case.

Progressive form of pulmonary Langenharns' cell histiocytosis in a female adult non-smoker

Little is known about the cause, nature, treatment and prognosis of pulmonary Langerhans' cell histiocytosis (LCH) in adults. We report the case of a 44-year-old female non-smoker suffering from pulmonary histiocytosis who after a 7-year remission period relapsed with both lung and bone disease. Using a combination of corticosteroids, methotrexate and bone irradiation treatment, the patient achieved total disease remission. The patient was a non-smoking female who has had long-term and swift remission of the disease on two occasions.

Proliferation of prostate cancer cells and activity of neutral endopeptidase is regulated by bombesin and IL-1beta with IL-1beta acting as a modulator of cellular differentiation

BACKGROUND

Neutral endopeptidase (NEP) is a cell-surface bound enzyme that cleaves and inactivates neuropeptides such as bombesin and substance P and is involved in the transition from hormonally regulated androgen-dependent prostate cancer (PC) to androgen-independent PC. Neuropeptides are implicated in growth regulation of different cell types and function as transmitters between the neuroendocrine and the immune system.

METHODS

NEP-expression, enzymatic activity of the membrane bound protein, cell proliferation, procalcitonin (PCT) production, and secretion as well as changes in cell morphology of prostatic cells were evaluated after treatment with the immunomodulatory cytokine interleukin-1beta (IL-1beta), neuropeptides (bombesin, substance P), and neuropeptide-conditioned media derived from a human neuroendocrine cell line.

RESULTS

Incubation of LNCaP tumor cells with IL-1beta resulted in a diminished proliferative activity, induction of neurite-like outgrowth which was accompanied by the formation of tubular-type mitochondria typical for neuronal/neuroendocrine cells, and an increased production and secretion of PCT. Conversely, proliferation of prostatic stromal cells was enhanced by the cytokine coming along with an increased number of Golgi-apparatuses and ER-cisternae. Bombesin had an antimitotic effect on LNCaP, but not on stromal cells. Substance P did not influence the growth of any of the cell types investigated, whereas neuropeptide-conditioned media exerted a slightly mitogenic effect on both cell types. The activity of LNCaP cell-surface bound NEP was enhanced by bombesin, but was diminished by substance P and neuropeptide-conditioned media.

CONCLUSIONS

Proliferation and activity of neuropeptide degrading NEP is regulated differently by immunomodulatory substances in PC cells and cells derived from the prostatic stroma with IL-1beta being a potent modulator of cellular differentiation and a potential target for anticancer drug design in PC cells.

Urinary levels of bombesin-related peptides in a population sample from northern Italy: potential role in the pathogenesis of chronic obstructive pulmonary disease

Bombesin-related peptides (BRP) are present in the lung and have various biological functions, including modulation of lung maturation. Many recent studies have suggested that BRP have a pathogenic role in airway wall remodeling in chronic obstructive pulmonary disease. The aim of this cross-sectional survey was to evaluate the distribution of urinary BRP excretion as a indirect marker of pulmonary BRP production and to assess the prevalence of smoking, chronic respiratory symptoms, chronic obstructive pulmonary disease, and asthma in a population sample from northern Italy. Associations between urinary BRP excretion and several respiratory and nonrespiratory variables were also evaluated. The only variable tested that was significantly predictive of high urinary levels of BRP was the presence of respiratory symptoms. In contrast to previous studies, smoking per se was not significantly associated with urinary BRP levels.

Bombesin down modulates pulmonary fibrosis elicited in mice by bleomycin

The role of bombesin was investigated in the course of the pulmonary inflammation and fibrosis (PF) elicited by the intratracheal (IT) or intravenous (i.v.) administration of bleomycin in mice. Bleomycin-induced alveolitis was associated with an accumulation of cells, presumably macrophages, containing bombesin, as evidenced by immunohistochemistry. Administration of bombesin by an osmotic minipump implanted IP, at a rate of 6 micrograms/h, decreased the lung hydroxyproline evident 15 days after IV or IT administration of bleomycin. In contrast, antibombesin monoclonal antibody 2A11 (mAb) increased the lung hydroxyproline content after IT administration of bleomycin. In addition, the mortality of bleomycin-injected mice was increased by the anti-bombesin mAb. Bombesin administration induced an increase, and anti-bombesin mAb induced a decrease, in the number of macrophages recovered from the bronchoalveolar lavage. Administration of bombesin did not change the mRNA levels of TNF-alpha, TGF-beta, and PDGF, as seen on Northern blots made with the lung RNA. Pulmonary platelet trapping, which was increased by a bleomycin injection, was decreased by an infusion of bombesin as demonstrated by the distribution of 111In-labeled platelets. This study indicates that bombesin act as an inhibitor of the development of pulmonary fibrosis, possibly by decreasing pulmonary platelet trapping.

Up-regulation of cytokine production in alveolar macrophages by histogranin, a novel endogenous pentadecapeptide

Recently, histogranin (HN), a newly found pentadecapeptide, was shown to enhance tumor necrosis factor (TNF) production by alveolar macrophages (AM). In this study, we have investigated whether HN was present in tissues rich with immune cells and further explored the effect of HN and [Ser1]HN on the production of TNF and other key cytokines. Relatively high levels of immunoreactive (ir)-HN were found in rat lung (14.9 pmol/g) and spleen (12.3 pmol/g), indicating its localization in close proximity to macrophages/monocytes and lymphocytes. Furthermore, HN and [Ser1]HN (10(-8)-10(-7) M) stimulated basal and lipopolysaccharide (LPS)-induced interleukin 1 (IL-1) mRNA expression and IL-1 release from rat AM. [Ser1]HN also stimulated basal and LPS-induced interleukin-6 (IL-6) release. Although HN did not affect the kinetics of cytokine production, the maximal enhancing effect of HN was seen at 3 h for TNF, 6 h for IL-1 and 18 h for IL-6. These data indicate that HN can up-regulate a cytokine cascade involving TNF, IL-1 and IL-6 and suggest a role for this endogenous peptide in immune regulation.

Antral G-cell and D-cell numbers in Helicobacter pylori infection: effect of H. pylori eradication

BACKGROUND

It has recently been recognized that Helicobacter pylori infection is associated with abnormalities in the regulation of gastrin secretion. We investigated whether there was a relationship between H. pylori infection and G-cell and D-cell numbers.

METHODS

The numbers of antral G cells and D cells were compared between 20 patients with duodenal ulcer and 24 volunteers, 12 with and 12 without H. pylori infection. The effect of eradication of H. pylori infection on G-cell number was also evaluated. Antral mucosal biopsy specimens were examined using immunohistochemical techniques specific for the presence of gastrin and somatostatin.

RESULTS

The number of G cells was significantly (P < 0.02) less in patients with duodenal ulcer than in either infected or uninfected controls (3.7 +/- 0.3 vs. 6.2 +/- 0.6 and 5.3 +/- 0.5 G cells per gland for infected and uninfected controls, respectively). The ratio of G-cells to D-cells was similar in duodenal ulcer patients (2.2) and uninfected controls (2.0). It was found that, although eradication of the H. pylori infection results in a dramatic reduction in stimulated gastrin secretion, it is not associated with a change in the numbers of antral G cells or D cells in patients with duodenal ulcer.

CONCLUSIONS

It is concluded that H. pylori infection-associated increase in gastrin secretion appear to be related to local factors regulating G-cell function.

The neuropeptide, neuromedin C, activates a potassium current in mouse macrophages

Neuromedin C (NmC) induced an outward current (Io(NmC)) in macrophages. Reversal potentials were dependent on external K+ concentrations ([K+]o) and independent of [Cl-]o. Tetraethylammonium (TEA) and quinidine effectively suppressed Io(NmC). Charybdotoxin (ChTX) and apamin had little effect. Io(NmC) was abolished in Ca(2+)-free EGTA-containing solution. These results suggest that MnC activates a Ca(2+)-dependent K+ current (IK,Ca) and can modulate activities in macrophages.