NK-1 antagonist CP99994 inhibits stress-induced mast cell degranulation in rats

Mast cell stabilizers: from pathogenic roles to targeting therapies

Mast cells (MCs) are bone-marrow-derived haematopoietic cells that are widely distributed in human tissues. When activated, they will release tryptase, histamine and other mediators that play major roles in a diverse array of diseases/disorders, including allergies, inflammation, cardiovascular diseases, autoimmune diseases, cancers and even death. The multiple pathological effects of MCs have made their stabilizers a research hotspot for the treatment of related diseases. To date, the clinically available MC stabilizers are limited. Considering the rapidly increasing incidence rate and widespread prevalence of MC-related diseases, a comprehensive reference is needed for the clinicians or researchers to identify and choose efficacious MC stabilizers. This review analyzes the mechanism of MC activation, and summarizes the progress made so far in the development of MC stabilizers. MC stabilizers are classified by the action mechanism here, including acting on cell surface receptors, disturbing signal transduction pathways and interfering exocytosis systems. Particular emphasis is placed on the clinical applications and the future development direction of MC stabilizers.

In vitro prediction of in vivo pseudo-allergenic response via MRGPRX2

In development of peptide therapeutics, rodents are commonly-used preclinical models when screening compounds for efficacy endpoints in the early stages of discovery projects. During the screening process, some peptides administered subcutaneously to rodents caused injection site reactions manifesting as localized swelling. Screening by postmortem evaluations of injection site swelling as a marker for local subcutaneous histamine release, were conducted in rats to select drug candidates without this adverse effect. Histological analysis of skin samples revealed that the injection site reactions were concurrent with mast cell degranulation, resulting in histamine release. Mast cell activation can be mediated by MRGPRX2, a GPCR that induces a pseudo-allergenic immune response. The present study demonstrates that a commercially-available cell-based MRGPRX2 assay reliably identifies compounds that induce histamine release or localized edema in ex vivo human and rodent skin samples. In vitro screening was subsequently implemented using the MRGPRX2 assay as a substitute for postmortem injection site evaluation, thus achieving a significant reduction in animal use. Thus, in cases where injection site reactions are encountered during in vivo screening, to enable faster screening during the early drug discovery process, an MRGPRX2 in vitro assay can be used as an efficient, more ethical tool with human translational value for the development of safer pharmacotherapies for patients.

Exercise training improves heart rate recovery in women with breast cancer

PURPOSE

To determine whether exercise training improves autonomic function in women with breast cancer (BC).

METHODS

Fifty-one patients (aged between 39 and 72 years) with a history of primary invasive BC within the previous 5 years and enrolled in the Mediterranean diet-based DIANA (Diet and Androgens)-5 Trial were subdivided in two groups: a ET group (n = 25) followed a formal ET program of moderate intensity (3 session/week on a bicycle at 60-70% VO2peak for 3 months, followed by one session/week until 1-year follow-up), while a control group (n = 26) did not perform any formal ET. At baseline and after 1-year, all patients underwent cardiopulmonary exercise stress test (CPET). Heart rate recovery (HRR) was calculated as the difference between heart rate at peak exercise and heart rate at first minute of the cool-down period.

RESULTS

There were no significant differences between groups in baseline anthropometrical, BC characteristics, metabolic profile, CPET parameters and HRR. Compared to controls, at 1-year follow-up ET group showed a significant improvement in VO2peak (from 12.6 ± 3.0 to 14.5 ± 3.3 ml/kg/min, p < 0.001; p < 0.001 between groups); and in HRR (from 17.6 ± 6.4 to 23.0 ± 8.3 beats/min, p < 0.001; p < 0.001 between groups). In ET group the changes in HRR directly correlated with changes in VO2peak (r = 0.58, p = 0.002).

CONCLUSIONS

Moderate intensity exercise training in BC survivors is associated with improvement of autonomic function. Whether the improvement of sympatho-vagal balance may favorably modulate some of the pathophysiological mechanisms implied in cancer evolution need further investigation.

Mast cell stabilisers

Mast cells play a critical role in type 1 hypersensitivity reactions. Indeed, mast cell mediators are implicated in many different conditions including allergic rhinitis, conjunctivitis, asthma, psoriasis, mastocytosis and the progression of many different cancers. Thus, there is intense interest in the development of agents which prevent mast cell mediator release or which inhibit the actions of such mediators once released into the environment of the cell. Much progress into the design of new agents has been made since the initial discovery of the mast cell stabilising properties of khellin from Ammi visnaga and the clinical approval of cromolyn sodium. This review critically examines the progress that has been made in the intervening years from the design of new agents that target a specific signalling event in the mast cell degranulation pathway to those agents which have been developed where the precise mechanism of action remains elusive. Particular emphasis is also placed on clinically used drugs for other indications that stabilise mast cells and how this additional action may be harnessed for their clinical use in disease processes where mast cells are implicated.

Twenty-first century mast cell stabilizers

Mast cell stabilizing drugs inhibit the release of allergic mediators from mast cells and are used clinically to prevent allergic reactions to common allergens. Despite the relative success of the most commonly prescribed mast cell stabilizer, disodium cromoglycate, in use for the preventative treatment of bronchial asthma, allergic conjunctivitis and vernal keratoconjunctivitis, there still remains an urgent need to design new substances that are less expensive and require less frequent dosing schedules. In this regard, recent developments towards the discovery of the next generation of mast cell stabilizing drugs has included studies on substances isolated from natural sources, biological, newly synthesized compounds and drugs licensed for other indications. The diversity of natural products evaluated range from simple phenols, alkaloids, terpenes to simple amino acids. While in some cases their precise mode of action remains unknown it has nevertheless sparked interest in the development of synthetic derivatives with improved pharmacological properties. Within the purely synthetic class of inhibitors, particular attention has been devoted to the inhibition of important signalling molecules including spleen TK and JAK3. The statin class of cholesterol-lowering drugs as well as nilotinib, a TK inhibitor, are just some examples of clinically used drugs that have been evaluated for their anti-allergic properties. Here, we examine each approach under investigation, summarize the test data generated and offer suggestions for further preclinical evaluation before their therapeutic potential can be realized.

[Psychological and biological background of the correlation between psoriasis and stress]

Stress is considered as a major contributor to the development and exacerbation of psoriasis by a significant proportion of patients and dermatologists. As both stressor and its effects are subject-dependent, thus extremely difficult to measure, our understanding of the exact role of stress in disease development was limited for a long time. In the past decade several new studies were carried out which expanded our knowledge on the pathophysiologic processes linking stress to psoriasis via with their objective measurements and the applied new techniques. The authors review the current literature of both psychological (alexithymia, personality, affect) and biological (cortisol, epinephrine, neurogenic inflammation) factors influencing stress perception and response in psoriasis. Results of recent investigations support previous reports about the interaction between stress and psoriasis with objective evidence. Knowing how effective stress-reducing psychopharmacologic and psychotherapeutic interventions are in the treatment of psoriasis the authors hope that this review contributes to a wider acceptance of the psychosomatic attitude in everyday dermatologic practice.

Changes in urine levels of substance P, vasoactive intestinal peptide and calcitonin-gene-related peptide in patients with urinary tract infections

Urinary tract infections (UTI) are important health problems and predisposing causes of UTI are not entirely known. Neuro-immune interactions play an important role in human health and disease. Capsaicin-sensitive sensory nerves which in nerve bladder extensively regulate immune system through neuropeptides such as substance P (SP), calcitonin-gene related peptide (CGRP) and vasoactive intestinal peptide (VIP). In addition these neuropeptides also have anti-bacterial effects. To determine how the levels of these peptides changes during UTI, 67 patients (50-90 years-old) diagnosed with UTI in Akdeniz University Faculty of Medicine Hospital were compared with 37 healthy people 50 years or older as the control group. Additionally, 7 patients with UTI symptoms (dysuria, urgency) but with sterile pyuria were also included in the study. Urine samples from 15 patients, whose symptoms regressed with control urine cultures being sterile, were taken after completion of the treatments. Urine neuropeptide levels were determined by ELISA. CGRP levels are significantly higher in patients with UTI, but did not associate with pyuria whereas SP and VIP levels were significantly lower in patients with sterile pyuria, indicating sensory nerve deficiency. Since CGRP exerts immunosuppressive effects, increased levels of the peptide may predispose to UTI. Furthermore, the connection between the observed sensory nerve deficiency and sterile pyuria warrants further studies.

Increasing substance P levels in serum and synovial tissues from patients with developmental dysplasia of the hip (DDH)

BACKGROUND

The tachykininergic neurotransmitters have been proved to be involved in the inflammatory progress and chronic pain in series of disease. The present study was undertaken to evaluate the levels of substance P (SP) and its receptors NK-1 receptor (NK-1R) in both serum and synovial tissues of hip joint from patients with different stages of DDH, and to detect the possible correlation of serum SP levels with pain sensation and dysfunction of the hip joint.

METHODS

SP levels in serum and synovial tissues from patients with DDH and DDH combined with osteoarthritis (DDH&OA) group were compared through immunohistochemistry (IHC), ELISA, and 2-step acetic acid extraction method respectively. Expression of NK-1R in synovial tissues was compared through IHC, quantitive Real-Time PCR (QRT-PCR) and Western-Blot. The severities of pain sensation and the functional activities of hip joint were assessed by Visual analogue scale (VAS) and Harris hip score (HHS). Correlations of serum SP levels with VAS, HHS and erythrocyte sedimentation rate (ESR) were evaluated respectively in these groups.

RESULTS

Significantly elevated serum SP levels were detected in group of DDH and DDH&OA compared to that in normal group. IHC, QRT-PCR as well as tissue Elisa showed that SP levels in synovial tissue of DDH&OA group is stronger than that in DDH group. Serum SP levels in each group have no gender differences. The enhanced SP levels in synovial tissue mainly came from the segregation of peripheral nerve endings. Serum SP correlated with VAS and HHS in patients with DDH&OA (Male + Female). Serum SP correlated with HHS in patients with DDH (Male). Serum SP levels also correlated with erythrocyte sedimentation rate (ESR) in patients with DDH&OA (Male + Female). Up-regulated expression of NK-1R was also observed in synovial tissue of patients with DDH&OA compared to patients with DDH, through western-blot, IHC, and QRT-PCR.

CONCLUSIONS

These findings indicated that the increasing SP levels in serum and synovial tissues, observed from patients with DDH to patients with DDH&OA, might associate with the loss of function and chronic pain sensation in hip joint. SP along with its receptors NK-1R might be involved in the progression of DDH into DDH&OA. In the future, inhibitors of SP as well as NK-1R may represent a novel pharmacotherapy target for pain relieving, inflammation alleviating and joint degeneration delaying for patients with DDH.

Tachykinins and their receptors: contributions to physiological control and the mechanisms of disease

The tachykinins, exemplified by substance P, are one of the most intensively studied neuropeptide families. They comprise a series of structurally related peptides that derive from alternate processing of three Tac genes and are expressed throughout the nervous and immune systems. Tachykinins interact with three neurokinin G protein-coupled receptors. The signaling, trafficking, and regulation of neurokinin receptors have also been topics of intense study. Tachykinins participate in important physiological processes in the nervous, immune, gastrointestinal, respiratory, urogenital, and dermal systems, including inflammation, nociception, smooth muscle contractility, epithelial secretion, and proliferation. They contribute to multiple diseases processes, including acute and chronic inflammation and pain, fibrosis, affective and addictive disorders, functional disorders of the intestine and urinary bladder, infection, and cancer. Neurokinin receptor antagonists are selective, potent, and show efficacy in models of disease. In clinical trials there is a singular success: neurokinin 1 receptor antagonists to treat nausea and vomiting. New information about the involvement of tachykinins in infection, fibrosis, and pruritus justifies further trials. A deeper understanding of disease mechanisms is required for the development of more predictive experimental models, and for the design and interpretation of clinical trials. Knowledge of neurokinin receptor structure, and the development of targeting strategies to disrupt disease-relevant subcellular signaling of neurokinin receptors, may refine the next generation of neurokinin receptor antagonists.

Substance P and vasoactive intestinal peptide levels in middle ear effusions of children

CONCLUSION

This is the first report demonstrating high levels of substance P (SP) that inversely correlate with vasoactive intestinal peptide (VIP) levels in middle ear effusions (MEEs) of patients with otitis media with effusion (OME). Increased SP and decreased VIP levels might play a role in the pathogenesis of chronic OME.

OBJECTIVE

The etiology of OME is multifactorial, and neurogenic inflammation may play a significant role. SP and VIP levels were not evaluated previously in MEEs of children with OME.

METHODS

Fifty patients aged 2-12 years (mean age 5.24 ± 2.64) were included in the study. MEEs were classified as mucoid or serous based on the gross appearance. SP and VIP levels were determined using ELISA.

RESULTS

High levels of SP were detected in MEEs. In addition SP levels were significantly higher in serous samples (2910.55 ± 307.96 vs 2218.55 ± 262.30 pg/ml). There were also age-dependent changes, such that SP levels were significantly higher in children aged 2-3 years compared with those who were 4-5 and 6-12 years old. VIP levels were undetectable in 30% of patients and the mean level of VIP was 50.91 ± 16.01 pg/ml in serous middle ear effusions and 54.86 ± 15.91 pg/ml in mucoid MEEs.

Expression of tachykinins and their receptors in plaque psoriasis with pruritus

BACKGROUND Various mediators of pruritus have been suggested that might be responsible for the mechanism of pruritus in psoriasis.

OBJECTIVES

To study the expression levels of members of the tachykinin family, substance P and neurokinin (NK) A and their receptors, NK-1 and NK-2, in psoriasis and to correlate their expression with the intensity of pruritus. A possible correlation with chronic stress and depression was also evaluated.

METHODS

Biopsies were obtained from 28 patients with chronic plaque psoriasis; the majority had pruritus. The samples were taken from lesional and nonlesional areas on the back and also from 10 healthy controls, for immunohistochemistry staining, and from lesional skin for radioimmunoassay. Prior to biopsy, the clinical severity of the psoriasis of each patient was assessed by the Psoriasis Area and Severity Index (PASI) and the intensity of pruritus was measured by using a visual analogue scale (VAS). Levels of depression and stress were measured using Beck's Depression Inventory (BDI) and the salivary cortisol test, respectively.

RESULTS

Substance P-, NKA- and NK-2 receptor-immunoreactive nerves, and non-neuronal inflammatory cells positive for substance P and NKA and their respective receptors, NK-1 and NK-2, were numerous in psoriasis compared with healthy controls. The numbers of substance P-positive nerves and NK-2 receptor-positive cells in lesional skin were significantly correlated to pruritus intensity. The cortisol ratio was inversely correlated with the number of NK-1 receptor-immunoreactive inflammatory cells in lesional and nonlesional psoriasis skin. There was also a positive correlation between the BDI score and the number of substance P-positive cells in nonlesional skin and with NK-1 receptor-positive cells in lesional and nonlesional skin.

CONCLUSIONS

Tachykinins may play a role in psoriasis per se, in addition to pruritus in this disease. Targeting the combined NK-1 and NK-2 receptors might be a possible treatment.

Changes in Tissue Substance P Levels in Patients With Carpal Tunnel Syndrome

BACKGROUND:

Although carpal tunnel syndrome (CTS) is the most common entrapment neuropathy in adults, its etiology is not completely known. Chronic inflammation, fibrosis of the transverse carpal ligament (TCL), and altered sensory response contribute to the symptoms.

OBJECTIVE:

Because substance P (SP) is known to be involved in neuropathic pain, chronic inflammation, and fibrosis, the present study evaluated changes in SP levels in patients with CTS.

METHODS:

TCL, median nerve adventitia, and synovial connective tissue of the middle flexor digitorum superficialis tendon samples from patients (n = 42) with CTS and healthy control subjects (n = 13) who were operated on for hand wounds were obtained at surgery. A group of these patients with CTS (n = 9) had received meloxicam treatment for 10 days before surgery. A 2-step acetic acid extraction was used to determine changes in SP levels in free nerve endings (neuronal) and in nonneuronal cells.

RESULTS:

Changes in SP levels were observed in both neuronal and nonneuronal tissues. SP levels increased in extracts of the TCL and synovial connective tissue of the middle flexor digitorum superficialis tendon but not in the median nerve adventitia of patients with CTS. Meloxicam pretreatment increased SP levels in nonneuronal components of the TCL.

CONCLUSION:

These findings suggest that SP contributes to the pain and inflammation associated with CTS. Further studies are required to evaluate the therapeutic potentials of SP receptor (NK1R) antagonists in CTS.

IL-33 augments substance P-induced VEGF secretion from human mast cells and is increased in psoriatic skin

The peptide substance P (SP) has been implicated in inflammatory conditions, such as psoriasis, where mast cells and VEGF are increased. A relationship between SP and VEGF has not been well studied, nor has any interaction with the proinflammatory cytokines, especially IL-33. Here we report that SP (0.1-10 microM) induces gene expression and secretion of VEGF from human LAD2 mast cells and human umbilical core blood-derived cultured mast cells (hCBMCs). This effect is significantly increased by coadministration of IL-33 (5-100 ng/mL) in both cell types. The effect of SP on VEGF release is inhibited by treatment with the NK-1 receptor antagonist 733,060. SP rapidly increases cytosolic calcium, and so does IL-33 to a smaller extent; the addition of IL-33 augments the calcium increase. SP-induced VEGF production involves calcium-dependent PKC isoforms, as well as the ERK and JNK MAPKs. Gene expression of IL-33 and histidine decarboxylase (HDC), an indicator of mast cell presence/activation, is significantly increased in affected and unaffected (at least 15 cm away from the lesion) psoriatic skin, as compared with normal control skin. Immunohistochemistry indicates that IL-33 is associated with endothelial cells in both the unaffected and affected sites, but is stronger and also associated with immune cells in the affected site. These results imply that functional interactions among SP, IL-33, and mast cells leading to VEGF release contribute to inflammatory conditions, such as the psoriasis, a nonallergic hyperproliferative skin inflammatory disorder with a neurogenic component.

Neuropeptides activate human mast cell degranulation and chemokine production

During neuronal-induced inflammation, mast cells may respond to stimuli such as neuropeptides in an FcepsilonRI-independent manner. In this study, we characterized human mast cell responses to substance P (SP), nerve growth factor (NGF), calcitonin gene-related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) and compared these responses to human mast cell responses to immunoglobulin E (IgE)/anti-IgE and compound 48/80. Primary cultured mast cells, generated from CD34(+) progenitors in the presence of stem cell factor and interleukin-6 (IL-6), and human cultured mast cells (LAD2) were stimulated with these and other stimuli (gastrin, concanavalin A, radiocontrast media, and mannitol) and their degranulation and chemokine production was assessed. VIP and SP stimulated primary human mast cells and LAD cells to degranulate; gastrin, concanavalin A, radiocontrast media, mannitol, CGRP and NGF did not activate degranulation. While anti-IgE stimulation did not induce significant production of chemokines, stimulation with VIP, SP or compound 48/80 potently induced production of monocyte chemoattractant protein-1, inducible protein-10, monokine induced by interferon-gamma (MIG), RANTES (regulated on activation, normal, T-cell expressed, and secreted) and IL-8. VIP, SP and compound 48/80 also activated release of tumour necrosis factor, IL-3 and granulocyte-macrophage colony-stimulating factor, but not IL-4, interferon-gamma or eotaxin. Human mast cells expressed surface neurokinin 1 receptor (NK1R), NK2R, NK3R and VIP receptor type 2 (VPAC2) but not VPAC1 and activation of human mast cells by IgE/anti-IgE up-regulated expression of VPAC2, NK2R, and NK3R. These studies demonstrate the pattern of receptor expression and activation of mast cell by a host of G-protein coupled receptor ligands and suggest that SP and VIP activate a unique signalling pathway in human mast cells. These results are likely to have direct relevance to neuronally induced inflammatory diseases.

Study of substance P and its receptor neurokinin-1 in psoriasis and their relation to chronic stress and pruritus

Substance P and its receptor(R) neurokinin (NK)-1 may have a role in the pathogenesis of psoriasis. Stress has been reported to play a role in the onset and exacerbation of psoriasis, which might include the substance P-NK-1 receptor(R) pathway. A feature of psoriasis, that has been correlated to the severity of stress and secretion of substance P, is pruritus. The objective of this study was to investigate the expression of substance P and the NK-1R in involved and noninvolved psoriatic skin, using a biotinylated streptavidin technique. Moreover, a possible correlation between the patient s level of chronic stress, measured by salivary cortisol samples, degree of lesional pruritus, measured by means of a visual analogue scale, and the expression of substance P- and the NK-1R, was investigated. There was a low number of substance P positive nerve fibres in noninvolved and involved skin, the major immunoreactivity for substance P being found in inflammatory cells. The number of substance P- and NK-1R positive inflammatory cells was increased in involved compared to noninvolved psoriatic skin. The substance P positive cells were mostly lymphocytes, while most of the NK-1R positive cells were mast cells. NK-1R immunoreactivity was also seen as a reticular pattern in the upper part of the epidermis of involved skin in the majority of the patients. Low cortisol ratios in the patients, being an indicator of chronic stress, were correlated to an increased number of substance P- and NK-1R positive inflammatory cells in noninvolved psoriatic skin, and higher cortisol ratios to the presence of keratinocyte NK-1R immunoreactivity in involved skin. The degree of pruritus could not be correlated to the number of substance P positive fibers nor cells. Nonneuronal substance P and its receptor NK-1 might have a role in psoriasis, also during chronic stress.

Neurokinin 1 receptor signaling mediates sex differences in μ and κ opioid-induced enhancement of contact hypersensitivity

Contact hypersensitivity (CHS) is a type of cutaneous inflammation that is exacerbated by neurogenic factors. Both mu- and kappa-opioids enhance CHS to a greater extent in females than males. It was hypothesized that potentiated neurokinin 1 (NK1) receptor signaling following opioid treatment accounts for sex differences in the magnitude of CHS. Following morphine or spiradoline treatment the NK1 receptor antagonist SR140,333 significantly attenuated the magnitude of CHS in females but not males. By contrast, the NK2 antagonist SR48968 had no effect on morphine modulation of CHS. Taken together, these data indicate that NK1 receptor signaling is a key mediator of sex differences in opioid-induced enhancement of CHS.

Neuroimmunoendocrine circuitry of the ‘brain-skin connection’

The skin offers an ideally suited, clinically relevant model for studying the crossroads between peripheral and systemic responses to stress. A 'brain-skin connection' with local neuroimmunoendocrine circuitry underlies the pathogenesis of allergic and inflammatory skin diseases, triggered or aggravated by stress. In stressed mice, corticotropin-releasing hormone, nerve growth factor, neurotensin, substance P and mast cells are recruited hierarchically to induce neurogenic skin inflammation, which inhibits hair growth. The hair follicle is both a target and a source for immunomodulatory stress mediators, and has an equivalent of the hypothalamus-pituitary-adrenal axis. Thus, the skin and its appendages enable the study of complex neuroimmunoendocrine responses that peripheral tissues launch upon stress exposure, as a basis for identifying new targets for therapeutic stress intervention.

Inhibition of substance P activity prevents stress-induced bladder damage

Substance P is a neuropeptide involved in inflammation, immune regulation and stress response. Stress may induce bladder damage by stimulating inflammatory response such as mast cell activation. We here examined the role substance P during stress-induced mast cell degranulation and urothelial injury in rat bladder. Adult Sprague-Dawley rats (200-270 g) were either exposed to cold-immobilization stress or substance P (SP) intracerebroventricularly. Different doses of substance P receptor (NK1R) antagonist CP 99994 were administered peripherally or centrally before the stress exposure. From each group, samples of the bladder were examined with light and electron microscope. Stress- and SP-injected centrally, increased the number of both granulated and degranulated mast cells. Ultrastructurally, urothelial degeneration with vacuolization in the cytoplasm and dilated intercellular spaces were seen. Both central and peripheral injection of CP 99994 prevented stress-induced urothelial degeneration as well as stress-induced mast cell degranulation. In conclusion, centrally and peripherally released substance P is involved in stress-induced bladder damage. Inhibition of NK1R prevents stress-induced pathological changes of urinary bladder and NK1R antagonist can be considered for the treatment of inflammatory bladder diseases.