IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8+ T cells in vivo.

The induction of antitumor effector T cells in the tumor microenvironment is a crucial event for cancer immunotherapy. Neurokinin receptor 2 (NK2R), a G protein-coupled receptor for neurokinin A (NKA), regulates diverse physiological functions. However, the precise role of NKA-NK2R signaling in antitumor immunity is unclear. Here, we found that an IFN-γ-STAT1 cascade augmented NK2R expression in CD8+ T cells, and NK2R-mediated NKA signaling was involved in inducing antitumor effector T cells in vivo. The administration of a synthetic analog of double-stranded RNA, polyinosinic-polycytidylic acid (poly I:C), into a liver cancer mouse model induced type I and type II IFNs and significantly suppressed the tumorigenesis of Hepa1-6 liver cancer cells in a STAT1-dependent manner. The reduction in tumor growth was diminished by the depletion of CD8+ T cells. IFN-γ stimulation significantly induced NK2R and tachykinin precursor 1 (encodes NKA) gene expression in CD8+ T cells. NKA stimulation combined with anti-CD3 monoclonal antibody (mAb) treatment significantly augmented IFN-γ and granzyme B production by CD8+ T cells compared with the anti-CD3 mAb alone in vitro. ERK1/2 phosphorylation and IκBα degradation in activated CD8+ T cells were suppressed under NK2R deficiency. Finally, we confirmed that tumor growth was significantly increased in NK2R-deficient mice compared with that in wild-type mice, and the antitumor effects of poly I:C were abolished by NK2R absence. These findings suggest that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector T cells in the tumor microenvironment, which contributes to the suppression of cancer cell tumorigenesis in vivo. In this study, we revealed that IFN-γ-STAT1-mediated NK2R expression is involved in the induction of antitumor effector CD8+ T cells in the tumor microenvironment, which contributes to suppressing the tumorigenesis of liver cancer cells in vivo.

IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells.

Neurokinin 2 receptor (NK2R), a G protein-coupled receptor for neurokinin A (NKA), a tachykinin family member, regulates various physiological functions including pain response, relaxation of smooth muscle, dilation of blood vessels, and vascular permeability. However, the precise role and regulation of NK2R expression in cancer cells have not been fully elucidated. In this study, we found that high NK2R gene expression was correlated with the poor survival of colorectal cancer patients, and Interferon (IFN-α/ß) stimulation significantly enhanced NK2R gene expression level of colon cancer cells in a Janus kinas 1/2 (JAK 1/2)-dependent manner. NKA stimulation augmented viability/proliferation and phosphorylation of Extracellular-signal-regulated kinase 1/2 (ERK1/2) levels of IFN-α/ß-treated colon cancer cells and NK2R blockade by using a selective antagonist reduced the proliferation in vitro. Administration of an NK2R antagonist alone or combined with polyinosinic-polycytidylic acid, a synthetic analog of double-stranded RNA, to CT26-bearing mice significantly suppressed tumorigenesis. NK2R-overexpressing CT26 cells showed enhanced tumorigenesis and metastatic colonization in both lung and liver after the inoculation into mice. These findings indicate that IFN-α/ß-mediated NK2R expression is related to the malignancy of colon cancer cells, suggesting that NK2R blockade may be a promising strategy for colon cancers.

Characterization of the Role of NKA in the Control of Puberty Onset and Gonadotropin Release in the Female Mouse.

The tachykinin neurokinin B (NKB, Tac2) is critical for proper GnRH release in mammals, however, the role of the other tachykinins, such as substance P (SP) and neurokinin A (NKA) in reproduction, is still not well understood. In this study, we demonstrate that NKA controls the timing of puberty onset (similar to NKB and SP) and stimulates LH release in adulthood through NKB-independent (but kisspeptin-dependent) mechanisms in the presence of sex steroids. Furthermore, this is achieved, at least in part, through the autosynaptic activation of Tac1 neurons, which express NK2R (Tacr2), the receptor for NKA. Conversely, in the absence of sex steroids, as observed in ovariectomy, NKA inhibits LH through a mechanism that requires the presence of functional receptors for NKB and dynorphin (NK3R and KOR, respectively). Moreover, the ability of NKA to modulate LH secretion is absent in Kiss1KO mice, suggesting that its action occurs upstream of Kiss1 neurons. Overall, we demonstrate that NKA signaling is a critical component in the central control of reproduction, by contributing to the indirect regulation of kisspeptin release.

Tachykinin upregulation in atopic dermatitis.

Context: Atopic dermatitis (AD) is a chronic, inflammatory, itching skin disorder, which may worsen due to stress, depression and anxiety. Tachykinins may be involved in inflammation signaling as well as they may have a role in stress, depression and anxiety. Objective: This study aimed to measure the expression of tachykinin markers, in the skin of patients with AD, and the correlation of these tachykinins with clinical and psychodemographic parameters. Materials and methods: Twenty-eight adult patients with AD were investigated regarding tachykinin expression in skin biopsies, using an immunohistochemical technique. The patients were characterized with clinical and psychodemographic parameters. Results: The number of substance P and neurokinin (NK)A positive nerve fibers, as well as NKA positive mononuclear dermal cells, was increased in lesional compared to non-lesional skin. Interestingly, the depression score and the number of dermal NK-1 receptor (R) positive cells in lesional as well as in non-lesional skin showed a correlation. Conclusion: These findings indicate an upregulation of the tachykinergic system in the inflamed skin of AD.

Tac1-Expressing Neurons in the Periaqueductal Gray Facilitate the Itch-Scratching Cycle via Descending Regulation.

Uncontrollable itch-scratching cycles lead to serious skin damage in patients with chronic itch. However, the neural mechanism promoting the itch-scratching cycle remains elusive. Here, we report that tachykinin 1 (Tac1)-expressing glutamatergic neurons in the lateral and ventrolateral periaqueductal gray (l/vlPAG) facilitate the itch-scratching cycle. We found that l/vlPAG neurons exhibited scratching-behavior-related neural activity and that itch-evoked scratching behavior was impaired after suppressing the activity of l/vlPAG neurons. Furthermore, we showed that the activity of Tac1-expressing glutamatergic neurons in the l/vlPAG was elevated during itch-induced scratching behavior and that ablating or suppressing the activity of these neurons decreased itch-induced scratching behavior. Importantly, activation of Tac1-expressing neurons induced robust spontaneous scratching and grooming behaviors. The scratching behavior evoked by Tac1-expressing neuron activation was suppressed by ablation of spinal neurons expressing gastrin-releasing peptide receptor (GRPR), the key relay neurons for itch. These results suggest that Tac1-expressing neurons in the l/vlPAG promote itch-scratching cycles.

The research of the possible mechanism and the treatment for capsaicin-induced cough.

Unexplained chronic cough (UCC) affects millions of patients worldwide. New therapeutic approaches to this condition are urgently needed, since current treatment options provide only symptomatic relief. Cough reflex hypersensitivity has been shown to play an important role in the pathogenesis of UCC. The transient receptor potential vanilloid type 1 (TRPV1) is present on peripheral terminals of airway sensory nerves and modulation of its activity represents a potential target for the pharmacological treatment of UCC. The aim of this study was to explore the efficacy and the possible mechanism of SB705498, a TRPV1 antagonist, for cough in a capsaicin-induced cough animal model (i.e. guinea pigs). Induction of cough by capsaicin was successfully implemented in the guinea pigs, and the animals that met the inclusion criteria were randomly divided into four treatment groups: (1) Saline inhalation group (NSInh group, N = 10, negative control group), (2) Codeine phosphate intraperitoneal injection group (CPInp group, N = 10, positive control group), (3) SB705498 inhalation group (SBInh group, N = 10), (4) SB705498 intragastric administration group (SBIng group, N = 10). After treatment with above compounds, the capsaicin-induced cough experiment was performed again. The cough numbers and the cough incubation periods were recorded to evaluate the antitussive effect of SB705498. Enzyme-linked immunosorbent assay (ELISA) testing and Immunohistochemistry (IHC) staining for substance P (SP), calcitonin gene related peptide (CGRP) and neurokinin A (NKA) expression in lung and brain tissues were performed as an indication of neurogenic inflammation. Hematoxylin-Eosin (H&E) staining was used to observe the pathology morphology of lung and brain tissues. When the CPInp, SBInh and SBIng groups were compared to the NSInh group, the cough numbers were significantly reduced (p < .001), while the cough incubation periods were significantly prolonged (P < .001). In addition, the expression of SP, CGRP and NKA in lung and brain tissue was reduced (P < .05). None of the animals in the four groups exhibited lung and brain parenchymal inflammation. The results from this study showed that SB705498 had a significant antitussive effect, could reduce the neurogenic inflammation by reducing the expression of SP, CGRP and NKA in a capsaicin-induced cough model of guinea pigs. The results further indicated that TRPV1 played an important role in UCC and SB705498 might be a promising therapeutic agent for UCC.

Renal sodium handling and blood pressure changes in gestational protein-restricted offspring: Role of renal nerves and ganglia neurokinin expression.

BACKGROUND: Considering long-term changes in renal sodium handling and blood pressure in maternal protein-restricted (LP) offspring, we assumed that the development of LP hypertension results from abnormal dorsal root ganglia (DRG) neurokinin expression associated with impaired responsiveness of renal sensory receptors, promoting a reduced urinary excretion of sodium. The present study investigates whether increased blood pressure in protein-restricted offspring would be associated with changes in the DRG cells and in renal pelvic wall expression of NK1R, SP and CGRP when compared to NP offspring. In addition, we assessed the tubular sodium handling, estimated by creatinine and lithium clearances before and after bilateral renal denervation in conscious LP offspring relative to age-matched NP counterparts. METHODS: Dams received a normal (NP) or low-protein diet (LP) during their entire pregnancy period. Male NP or LP offspring underwent bilateral surgical renal denervation before the 8-week renal functional test and blood pressure measurements. Immunofluorescence staining in DRG cells was assessed in optical sections by confocal laser scanning microscope. RESULTS: The current data demonstrated a sustained rise in blood pressure associated with a decrease in fractional excretion of sodium (FENa) by reducing post-proximal tubule sodium rejection in 16-wk old LP rats relative to age-matched NP counterparts. According to this study, bilateral renal denervation attenuated blood pressure and increased FENa in LP offspring. Furthermore, an immunohistochemical analysis showed a reduced expression of SP and CGRP in DRGs of LP when compared with NP rats. Renal pelvis of LP rats did not show a strong CGRP expression related to NP rats, whereas there was no change in SP immunostaining. CONCLUSIONS: These observations raise the possibility that impaired DRG and pelvic neurokinin expression associated with responsiveness of renal sensory receptors in 16-wk old LP offspring are conducive to excess renal reabsorption of sodium and development of hypertension in this programmed model.

Tac1 Signaling Is Required for Sexual Maturation and Responsiveness of GnRH Neurons to Kisspeptin in the Male Mouse.

The tachykinins substance P (SP) and neurokinin A (Tac1) have emerged as novel regulators of kisspeptin/GnRH release. Recently, we documented that SP modulates reproductive function in the female mouse. Here, we extended this characterization to the male mouse. Tac1-/- male mice showed delayed puberty onset. They also presented significantly decreased expression levels of Pdyn (dynorphin) and Nos1 (nitric oxide synthase) in the mediobasal hypothalamus and elevated Gnrh1 levels. Unexpectedly, the response of Tac1-/- mice to central kisspeptin or senktide (neurokinin B receptor-agonist) administration was significantly decreased compared with controls, despite the preserved ability of GnRH neurons to stimulate luteinizing hormone release as demonstrated by central N-methyl-D-aspartate receptor administration, suggesting a deficit at the GnRH neuron level. Importantly, we demonstrated that kisspeptin receptor and SP receptor (NK1R) heterodimerize, indicating that changes in the SP tone could alter the responsiveness of GnRH neurons to kisspeptin. Finally, electrophysiological recordings from arcuate Kiss1 neurons showed that, although virtually all Kiss1 neurons responded to NKB and senktide, only half responded to an NK1R agonist and none to the neurokinin A receptor agonist at a 1-µM dose. In summary, we provide compelling evidence for a role of Tac1 in the control of reproductive function in the male mouse, suggesting a predominant central action that may involve a change in the balance of neural factors that control GnRH expression.

Altered expression of the tachykinins substance P/neurokinin A/hemokinin-1 and their preferred neurokinin 1/neurokinin 2 receptors in uterine leiomyomata.

OBJECTIVE: To study the expression levels of tachykinins and tachykinin receptors in uterine leiomyomas and matched myometrium. DESIGN: Laboratory study. SETTING: University research laboratories and academic hospital. PATIENT(S): Women undergoing hysterectomy for symptomatic leiomyomas. INTERVENTION(S): Quantitative polymerase chain reaction, immunohistochemistry and Western blot. MAIN OUTCOME MEASURE(S): Expression and tissue immunostaining of substance P, neurokinin A, hemokinin-1, neurokinin 1 receptor full-length (NK1R-Fl) and truncated (NK1R-Tr) isoforms, and neurokinin 2 receptor (NK2R) in paired samples of leiomyoma and adjacent normal myometrium. RESULT(S): TAC1 messenger RNA (mRNA) was significantly up-regulated in leiomyomas, whereas intense immunoreaction for the three peptides was particularly abundant in connective tissue cells. Differential regulation of TACR1 mRNA was observed, and at the protein level there was a significant increased expression of NK1R short isoform (NK1R-Tr). TACR2 mRNA was significantly up-regulated in leiomyomas, although levels of NK2R protein were similar in normal and tumor cells. CONCLUSION(S): These and our previous data demonstrate that the whole tachykinin system is differentially regulated in leiomyomas. The increased expression of NK1R-Tr might stimulate leiomyoma growth in a similar way to that observed in other steroid-dependent tumors.

Frequent promoter hypermethylation of tachykinin-1 and tachykinin receptor type 1 is a potential biomarker for head and neck cancer.

AIM: The aim of this study was to define TAC1 and TACR1 methylation profiles for head and neck squamous cell carcinoma (HNSCC) tumors at diagnosis and follow-up and to evaluate their prognostic significance and value as a biomarker of recurrence. MATERIALS AND METHODS: TAC1 and TACR1 expression was measured in a panel of cell lines by quantitative RT-PCR. The TAC1 and TACR1 promoter methylation status was determined by quantitative methylation-specific PCR. RESULTS: Methylation was associated with TAC1 and TACR1 transcription inhibition. TAC1 methylation in 49/100 (49 %) of HNSCC tumor specimens significantly correlated with p16 methylation (P = 0.010), E-cadherin methylation (P = 0.041), galanin methylation (P = 0.037), and disease-free survival (P = 0.002). Stage III and IV patients manifesting TAC1 hypermethylation had significantly shorter survivals than did patients without TAC1 methylation (P = 0.022). TACR1 methylation in 34/100 (34 %) cases was significantly correlated with galanin methylation (P = 0.014) and GALR1 methylation (P = 0.004). TAC1 promoter hypermethylation was statistically correlated with reduced disease-free survival (log-rank test, P = 0.002). In multivariate logistic-regression analysis, methylation of TAC1 and of the gene pair TAC1 and TACR1 was associated with an odds ratio for recurrence of 3.35 (95 % CI, 1.37-8.19; P = 0.008) and 5.09 (95 % CI, 1.44-18.02; P = 0.011), respectively. CONCLUSION: CpG hypermethylation is a likely mechanism of TAC1 and TACR1 gene inactivation, supporting the hypothesis that TAC1 and TACR1 play a role in the tumorigenesis of HNSCC and that this hypermethylation may serve as an important biomarker.

Copper(II) complexes of neurokinin A with point mutation (S5A) and products of copper-catalyzed oxidation; role of serine residue in peptides containing neurokinin A sequence.

A potentiometric, spectroscopic (UV-visible, CD and EPR) and electrospray ionization mass spectrometric (ESI-MS) study of Cu(II) binding to the neurokinin A with point mutation (S5A) (ANKA), His-Lys-Thr-Asp-Ala(5)-Phe-Val-Gly-Leu-Met-NH2 and its N-acethyl derivative (Ac-ANKA), Ac-His-Lys-Thr-Asp-Ala(5)-Phe-Val-Gly-Leu-Met-NH2 were carried out. For the ANKA and Ac-ANKA the additional deprotonation was not observed. It suggests that for the tachykinin peptides with C-terminal sequence of neurokinin A for the additional deprotonation the presence of the serine residue is necessary. For the Cu(II)-ANKA 1:2 system at physiological pH 7.4 the CuH2L2 species is present with histamine-like 4N, 2×{NH2,NIm} coordination mode. With increasing pH the deprotonation and coordination of amide nitrogen atoms occur and the CuH-2L, CuH-3L complexes are formed. In pH range 4.5 - 9.5 the dimeric Cu2HL2, Cu2L2 and Cu2H-1L2 species in solution are also present. To elucidate the products of the copper(II)- catalyzed oxidation of the ANKA and Ac-ANKA, the liquid chromatography-mass spectrometry (LC-MS) method and Cu(II)/hydrogen peroxide as a model oxidizing system were employed. In the presence of hydrogen peroxide with 1:1 peptide-H2O2 molar ratio for both peptides the oxidation of the methionine residue to methionine sulfoxide was observed. For the Cu(II)-peptide-hydrogen peroxide in 1:2:2 molar ratio systems oxidations of the histidine residues to 2-oxo-histidines and methionine sulfoxide to methionine sulfone were detected.

An indirect role for oncomir-519b in the expression of truncated neurokinin-1 in breast cancer cells.

Neurokinin 1 (NK1) encodes full-length (NK1-FL) and truncated (NK1-Tr) receptors, with distinct 3' UTR. NK1-Tr exerts oncogenic functions and is increased in breast cancer (BC). Enhanced transcription of NK1 resulted in higher level of NK1-Tr. The 3' UTR of these two transcripts are distinct with NK1-Tr terminating at a premature stop codon. NK1-Tr mRNA gained an advantage over NK1-FL with regards to translation. This is due to the ability of miR519B to interact with sequences within the 3' UTR of NK1-FL, but not NK1-Tr since the corresponding region is omitted. MiR519b suppressed the translation of NK1-FL in T47D and MDA-MB-231 resulting in increased NK1-Tr protein. Cytokines can induce the transcription of NK1. However, our studies indicated that translation appeared to be independent of cytokine production by the BC cells (BCCs). This suggested that transcription and translation of NK1 might be independent. The findings were validated in vivo. MiR-519b suppressed the growth of MDA-MB-231 in 7/10 nude BALB/c. In total, increased NK1-Tr in BCCs is due to enhanced transcription and suppressed translation of NK1-FL by miR-519b to reduced tumor growth. In summary, we report on miRNA as a method to further regulate the expression of a spiced variant to promote oncogenesis. In addition, the findings have implications for therapy with NK1 antagonists. The oncogenic effect of NK1-Tr must be considered to improve the efficacy of current drugs to NK1.

Neuropeptide signaling activates dendritic cell-mediated type 1 immune responses through neurokinin-2 receptor.

Neurokinin A (NKA), a neurotransmitter distributed in the central and peripheral nervous system, strictly controls vital responses, such as airway contraction, by intracellular signaling through neurokinin-2 receptor (NK2R). However, the function of NKA-NK2R signaling on involvement in immune responses is less-well defined. We demonstrate that NK2R-mediated neuropeptide signaling activates dendritic cell (DC)-mediated type 1 immune responses. IFN-γ stimulation significantly induced NK2R mRNA and remarkably enhanced surface protein expression levels of bone marrow-derived DCs. In addition, the DC-mediated NKA production level was significantly elevated after IFN-γ stimulation in vivo and in vitro. We found that NKA treatment induced type 1 IFN mRNA expressions in DCs. Transduction of NK2R into DCs augmented the expression level of surface MHC class II and promoted Ag-specific IL-2 production by CD4(+) T cells after NKA stimulation. Furthermore, blockade of NK2R by an antagonist significantly suppressed IFN-γ production by both CD4(+) T and CD8(+) T cells stimulated with the Ag-loaded DCs. Finally, we confirmed that stimulation with IFN-γ or TLR3 ligand (polyinosinic-polycytidylic acid) significantly induced both NK2R mRNA and surface protein expression of human PBMC-derived DCs, as well as enhanced human TAC1 mRNA, which encodes NKA and Substance P. Thus, these findings indicate that NK2R-dependent neuropeptide signaling regulates Ag-specific T cell responses via activation of DC function, suggesting that the NKA-NK2R cascade would be a promising target in chronic inflammation caused by excessive type 1-dominant immunity.

An antinociceptive role for substance P in acid-induced chronic muscle pain.

Release of substance P (SP) from nociceptive nerve fibers and activation of its receptor neurokinin 1 (NK1) are important effectors in the transmission of pain signals. Nonetheless, the role of SP in muscle pain remains unknown. Here we show that a single i.m. acid injection in mice lacking SP signaling by deletion of the tachykinin precursor 1 (Tac1) gene or coadministration of NK1 receptor antagonists produces long-lasting hyperalgesia rather than the transient hyperalgesia seen in control animals. The inhibitory effect of SP was found exclusively in neurons expressing acid-sensing ion channel 3, where SP enhances M-channel-like potassium currents through the NK1 receptor in a G protein-independent but tyrosine kinase-dependent manner. Furthermore, the SP signaling could alter action potential thresholds and modulate the expression of TTX-resistant sodium currents in medium-sized muscle nociceptors. Thus, i.m. SP mediates an unconventional NK1 receptor signal pathway to inhibit acid activation in muscle nociceptors, resulting in an unexpected antinociceptive effect against chronic mechanical hyperalgesia, here induced by repeated i.m. acid injection.

IFN-γ elevates airway hyper-responsiveness via up-regulation of neurokinin A/neurokinin-2 receptor signaling in a severe asthma model.

The adoptive transfer of OVA-specific Th1 cells into WT mice followed by OVA inhalation induces a significant elevation of airway hyper-responsiveness (AHR) with neutrophilia but not mucus hypersecretion. Here, we demonstrate that the airway inflammation model, pathogenically characterized as severe asthma, was partly mimicked by i.n. administration of IFN-γ. The administration of IFN-γ instead of Th1 cells caused AHR elevation but not neutrophilia, and remarkably induced neurokinin-2 receptor (NK2R) expression along with neurokinin A (NKA) production in the lung. To evaluate whether NKA/NK2R was involved in airway inflammation, we first investigated the role of NKA/NK2R-signaling in airway smooth muscle cells (ASMCs) in vitro. NK2R mRNA expression was significantly augmented in tracheal tube-derived ASMCs of WT mice but not STAT-1(-/-) mice after stimulation with IFN-γ. In addition, methacholine-mediated Ca(2+) influx into the ASMCs was significantly reduced in the presence of NK2R antagonist. Moreover, the NK2R antagonist strongly inhibited IFN-γ-dependent AHR elevation in vivo. Thus, these results demonstrated that IFN-γ directly acts on ASMCs to elevate AHR via the NKA/NK2R-signaling cascade. Our present findings suggested that NK2R-mediated neuro-immuno crosstalk would be a promising target for developing novel drugs in Th1-cell-mediated airway inflammation, including severe asthma.

Substance P induces adverse myocardial remodelling via a mechanism involving cardiac mast cells.

AIMS: Substance P and neurokinin A (NKA) are sensory nerve neuropeptides encoded by the TAC1 gene. Substance P is a mast cell secretagogue and mast cells are known to play a role in adverse myocardial remodelling. Therefore, we wondered whether substance P and/or NKA modulates myocardial remodelling via a mast cell-mediated mechanism. METHODS AND RESULTS: Volume overload was induced by aortocaval fistula in TAC1(-/-) mice and their respective wild types. Left ventricular internal diameter of wild-type (WT) fistulas increased by 31.9%; this was prevented in TAC1(-/-) mice (4.2%). Matrix metalloproteinase (MMP) activity was significantly increased in WT fistula mice and was prevented in TAC1(-/-) mice. Myocardial collagen volume fraction was decreased in WT fistula mice; this collagen degradation was not observed in the TAC1(-/-) group. There were no significant differences between any groups in tumour necrosis factor (TNF)-α or cell death. Cardiac mast cells were isolated from rat hearts and stimulated with substance P or NKA. We found that these cells degranulated only to substance P, via the neurokinin-1 receptor. To determine the effect of substance P on mast cells in vivo, volume overload was created in Sprague-Dawley rats treated with the NK-1 receptor antagonist L732138 (5 mg/kg/day) for a period of 3 days. L732138 prevented: (i) increases in cardiac mast cell density; (ii) increased myocardial TNF-α; and (iii) collagen degradation. CONCLUSIONS: Our studies suggest that substance P may be important in mediating adverse myocardial remodelling secondary to volume overload by activating cardiac mast cells, leading to increased TNF-α and MMP activation with subsequent degradation of the extracellular matrix.

Autocrine regulation of human sperm motility by tachykinins.

BACKGROUND: We examined the presence and function of tachykinins and the tachykinin-degrading enzymes neprilysin (NEP) and neprilysin-2 (NEP2) in human spermatozoa. METHODS: Freshly ejaculated semen was collected from forty-eight normozoospermic human donors. We analyzed the expression of substance P, neurokinin A, neurokinin B, hemokinin-1, NEP and NEP2 in sperm cells by reverse-transcriptase polymerase chain reaction (RT-PCR), western blot and immunocytochemistry assays and evaluated the effects of the neprilysin and neprilysin-2 inhibitor phosphoramidon on sperm motility in the absence and presence of tachykinin receptor-selective antagonists. Sperm motility was measured using WHO procedures or computer-assisted sperm analysis (CASA). RESULTS: The mRNAs of the genes that encode substance P/neurokinin A (TAC1), neurokinin B (TAC3), hemokinin-1 (TAC4), neprilysin (MME) and neprilysin-2 (MMEL1) were expressed in human sperm. Immunocytochemistry studies revealed that tachykinin and neprilysin proteins were present in spermatozoa and show specific and differential distributions. Phosphoramidon increased sperm progressive motility and its effects were reduced in the presence of the tachykinin receptor antagonists SR140333 (NK1 receptor-selective) and SR48968 (NK2 receptor-selective) but unmodified in the presence of SR142801 (NK3 receptor-selective). CONCLUSION: These data show that tachykinins are present in human spermatozoa and participate in the regulation of sperm motility. Tachykinin activity is regulated, at least in part, by neprilysins.

Acute morphine effects on respiratory activity in mice with target deletion of the tachykinin 1 gene (Tac1-/-).

Search for physiological mechanisms which could antagonize the opioid-induced respiratory depression is of important clinical value. In this study, we investigated the acute effects of morphine on respiratory activity in genetically modified newborn (P2) mice with target deletion of the (Tac1 -/-) gene lacking substance P (SP) and neurokinin A (NKA). In vivo, as shown with whole-body flow barometric plethysmography technique, morphine induced significantly attenuated minute ventilation during intermittent hypoxia in control animals. In contrast, knockout mice revealed significant increase in minute ventilation. In vitro, in brainstem preparation, knockout mice demonstrated greater changes in burst frequency during intermittent anoxia challenge. The data suggest that hereditary deficiency in tachykinins, SP and NKA results in more robust hypoxic response in newborn Tac1-/- mice during respiratory depression induced by morphine.

Expression of neuropeptides and their degrading enzymes in ACD.

BACKGROUND: Sensory neuropeptides such as neurokinin A or substance P modulate skin and immune cells the functions of neurokinin receptor activation during neurogenic inflammation. Zinc metalloproteases, such as neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE), effectively control the bioavailability of these neuropeptide mediators, which are released from sensory nerves, immune and skin cells during cutaneous responses to endogenous or exogenous noxious stimuli. Recently, studies have suggested that neuropeptides are one of the major pathogenetic fact in many dermatoses, such as allergic contact dermatitis (ACD), atopic dermatitis and psoriasis. AIM: To investigate the expression of major neuropeptides, SP and its degrading enzymes such as NEP and ACE, in the lesions of ACD. METHODS: A skin biopsy was obtained from 10 patients with ACD. We analysed the expression of these molecules by immunohistochemical staining, confocal laser scanning microscopy, western blotting and reverse transcription PCR. RESULTS: There was a significant increase in expression of SP in keratinocytes from ACD lesions compared with those in control skin. There was also increased expression of ACE but not NEP in ACD. CONCLUSION: Neuropeptides and their degrading enzymes, particularly SP and ACE, have a significant role in the pathogenesis of ACD.

Stromal-derived factor-1alpha induces a non-canonical pathway to activate the endocrine-linked Tac1 gene in non-tumorigenic breast cells.

The chemokine Stromal-derived factor-1alpha (SDF-1alpha) interacts with seven transmembrane (TM) G-protein-coupled receptor (GPR), CXCR4. SDF-1alpha is linked to inflammation, chemoattraction, cancer metastasis, and hematopoiesis. Tachykinin (Tac1) peptides bind seven transmembrane (TM), GPR and are involved in tumor promotion. SDF-1alpha regulates Tac1 expression in non-tumorigenic breast cells through a bimodal pattern with repression at high levels through nuclear factor-kappa B (NFkappaB) activation. This study focuses on the mechanism of activation at low SDF-1alpha in MCF12A non-tumorigenic breast cells. Reporter gene assays with the 5' flanking region of Tac1 (exon 1 omitted) and co-transfection with the repressor of cAMP response element (CREB) (ICER), and transfection with the CRE sites mutated, verified critical roles for CRE sites in SDF-1alpha-mediated Tac1 activation. Western blots and functional assays with specific inhibitors indicated that SDF-1alpha phosphorylated CREB (P-CREB) via Galpha(i)2-PI3K-protein kinase C (PKC)zeta-p38-extracellular signal-regulated kinase (ERK) and no evidence of cAMP-PKA pathway. This observation is different from previous studies that reported CREB-phosphorylated PKA pathway in the activation of Tac1 in bone marrow stromal cells. This suggests cell specificity in Tac1 expression. In conclusion, this study reports on a non-canonical pathway in Tac1 activation by SDF-1alpha. This finding is significant, since Tac1 is relevant to breast cancer metastasis, to bone marrow where stromal cells have a significant facilitating function.