Effect of VIP on the balance between cytokines and master regulators of activated helper T cells

Bordetella spp. utilize the type 3 secretion system to manipulate the VIP/VPAC2 signaling and promote colonization and persistence of the three classical Bordetella in the lower respiratory tract

Introduction

Bordetella are respiratory pathogens comprised of three classical Bordetella species: B. pertussis, B. parapertussis, and B. bronchiseptica. With recent surges in Bordetella spp. cases and antibiotics becoming less effective to combat infectious diseases, there is an imperative need for novel antimicrobial therapies. Our goal is to investigate the possible targets of host immunomodulatory mechanisms that can be exploited to promote clearance of Bordetella spp. infections. Vasoactive intestinal peptide (VIP) is a neuropeptide that promotes Th2 anti-inflammatory responses through VPAC1 and VPAC2 receptor binding and activation of downstream signaling cascades.

Methods

We used classical growth in vitro assays to evaluate the effects of VIP on Bordetella spp. growth and survival. Using the three classical Bordetella spp. in combination with different mouse strains we were able to evaluate the role of VIP/VPAC2 signaling in the infectious dose 50 and infection dynamics. Finally using the B. bronchiseptica murine model we determine the suitability of VPAC2 antagonists as possible therapy for Bordetella spp. infections.

Results

Under the hypothesis that inhibition of VIP/VPAC2 signaling would promote clearance, we found that VPAC2-/- mice, lacking a functional VIP/VPAC2 axis, hinder the ability of the bacteria to colonize the lungs, resulting in decreased bacterial burden by all three classical Bordetella species. Moreover, treatment with VPAC2 antagonists decrease lung pathology, suggesting its potential use to prevent lung damage and dysfunction caused by infection. Our results indicate that the ability of Bordetella spp. to manipulate VIP/VPAC signaling pathway appears to be mediated by the type 3 secretion system (T3SS), suggesting that this might serve as a therapeutical target for other gram-negative bacteria.

Conclusion

Taken together, our findings uncover a novel mechanism of bacteria-host crosstalk that could provide a target for the future treatment for whooping cough as well as other infectious diseases caused primarily by persistent mucosal infections.

Modified BuShenYiQi formula alleviates experimental allergic asthma in mice by negative regulation of type 2 innate lymphoid cells and CD4+ type 9 helper T cells and the VIP-VPAC2 signalling pathway

CONTEXT

Modified BuShenYiQi formula (M-BYF) is derived from BuShenYiQi formula, used for the treatment of allergic asthma. The exact effect and mechanism of M-BYF on the improvement of asthma remain unclear.

OBJECTIVE

We investigated the mechanism underlying the therapeutic effect of M-BYF on allergic asthma.

MATERIALS AND METHODS

The asthma model was established in female BALB/c mice that were sensitized and challenged with ovalbumin (OVA). Mice in the treated groups were orally treated once a day with M-BYF (7, 14 and 28 g/kg/d) or dexamethasone before OVA challenge. Control and Model group received saline. Pathophysiological abnormalities and percentages of lung type 2 innate lymphoid cells (ILC2s) and Th9 cells were measured. Expression levels of type 2 cytokines and transcription factors required for these cells function and differentiation were analysed. Expression of vasoactive intestinal polypeptide (VIP)-VPAC2 signalling pathway-related proteins, and percentages of VIP expressing (VIP⁺) cells and VPAC2, CD90 co-expressing (VPAC2⁺CD90⁺) cells were detected.

RESULTS

M-BYF alleviated airway hyperresponsiveness, inflammation, mucus hypersecretion and collagen deposition in asthmatic mice. M-BYF down-regulated percentages of ILC2s and Th9 cells with lower expression of GATA3, PU.1 and IRF4, reduced IL-5, IL-13, IL-9 and VIP production. The decrease in the expression of VIP-VPAC2 signalling pathway and percentages of VIP⁺ cells, VPAC2⁺CD90⁺ cells were observed after M-BYF treatment. The LD₅₀ value of M-BYF was higher than 90 g/kg.

DISCUSSION AND CONCLUSIONS

M-BYF alleviated experimental asthma by negatively regulating ILC2s and Th9 cells and the VIP-VPAC2 signalling pathway. These findings provide the theoretical basis for future research of M-BYF in asthma patient population.

Role of Neuroimmune Crosstalk in Mediating the Anti-inflammatory and Analgesic Effects of Acupuncture on Inflammatory Pain

Inflammatory pain is caused by peripheral tissue injury and inflammation. Inflammation leads to peripheral sensitization, which may further cause central sensitization, resulting in chronic pain and progressive functional disability. Neuroimmune crosstalk plays an essential role in the development and maintenance of inflammatory pain. Studies in recent years have shown that acupuncture can exert anti-inflammatory and analgesic effects by regulating peripheral (i.e., involving local acupoints and inflamed regions) and central neuroimmune interactions. At the local acupoints, acupuncture can activate the TRPV1 and TRPV2 channels of mast cells, thereby promoting degranulation and the release of histamine, adenosine, and other immune mediators, which interact with receptors on nerve endings and initiate neuroimmune regulation. At sites of inflammation, acupuncture enables the recruitment of immune cells, causing the release of opioid peptides, while also exerting direct analgesic effects via nerve endings. Furthermore, acupuncture promotes the balance of immune cells and regulates the release of inflammatory factors, thereby reducing the stimulation of nociceptive receptors in peripheral organs. Acupuncture also alleviates peripheral neurogenic inflammation by inhibiting the release of substance P (SP) and calcitonin gene-related peptide from the dorsal root ganglia. At the central nervous system level, acupuncture inhibits the crosstalk between glial cells and neurons by inhibiting the p38 MAPK, ERK, and JNK signaling pathways and regulating the release of inflammatory mediators. It also reduces the excitability of the pain pathway by reducing the release of excitatory neurotransmitters and promoting the release of inhibitory neurotransmitters from neurons and glial cells. In conclusion, the regulation of neuroimmune crosstalk at the peripheral and central levels mediates the anti-inflammatory and analgesic effects of acupuncture on inflammatory pain in an integrated manner. These findings provide novel insights enabling the clinical application of acupuncture in the treatment of inflammatory diseases.

Mechanism of Immunoregulatory Properties of Vasoactive Intestinal Peptide in the K/BxN Mice Model of Autoimmune Arthritis

The K/BxN mouse model of rheumatoid arthritis (RA) closely resembles the human disease. In this model, arthritis results from activation of autoreactive KRN T cells recognizing the glycolytic enzyme glucose-6-phosphate isomerase (GPI) autoantigen, which provides help to GPI-specific B cells, resulting in the production of pathogenic anti-GPI antibodies that ultimately leads to arthritis symptoms from 4 weeks of age. Vasoactive intestinal peptide (VIP) is a neuropeptide broadly distributed in the central and peripheral nervous system that is also expressed in lymphocytes and other immune cell types. VIP is a modulator of innate and adaptive immunity, showing anti-inflammatory and immunoregulatory properties. Basically, this neuropeptide promotes a shift in the Th1/Th2 balance and enhances dedifferentiation of T regulatory cells (Treg). It has demonstrated its therapeutic effects on the collagen-induced arthritis (CIA) mouse model of RA. In the present hypothesis and theory article, we propose that the immunoregulatory properties of VIP may be due likely to the inhibition of T cell plasticity toward non-classic Th1 cells and an enhanced follicular regulatory T cells (Tfr) activity. The consequences of these regulatory properties are the reduction of systemic pathogenic antibody titers.

A Clinical Approach for the Use of VIP Axis in Inflammatory and Autoimmune Diseases

The neuroendocrine and immune systems are coordinated to maintain the homeostasis of the organism, generating bidirectional communication through shared mediators and receptors. Vasoactive intestinal peptide (VIP) is the paradigm of an endogenous neuropeptide produced by neurons and endocrine and immune cells, involved in the control of both innate and adaptive immune responses. Exogenous administration of VIP exerts therapeutic effects in models of autoimmune/inflammatory diseases mediated by G-protein-coupled receptors (VPAC1 and VPAC2). Currently, there are no curative therapies for inflammatory and autoimmune diseases, and patients present complex diagnostic, therapeutic, and prognostic problems in daily clinical practice due to their heterogeneous nature. This review focuses on the biology of VIP and VIP receptor signaling, as well as its protective effects as an immunomodulatory factor. Recent progress in improving the stability, selectivity, and effectiveness of VIP/receptors analogues and new routes of administration are highlighted, as well as important advances in their use as biomarkers, contributing to their potential application in precision medicine. On the 50th anniversary of VIP's discovery, this review presents a spectrum of potential clinical benefits applied to inflammatory and autoimmune diseases.

A Synthetic Agonist to Vasoactive Intestinal Peptide Receptor-2 Induces Regulatory T Cell Neuroprotective Activities in Models of Parkinson's Disease

A paradigm shift has emerged in Parkinson’s disease (PD) highlighting the prominent role of CD4⁺ Tregs in pathogenesis and treatment. Bench to bedside research, conducted by others and our own laboratories, advanced a neuroprotective role for Tregs making pharmacologic transformation of immediate need. Herein, a vasoactive intestinal peptide receptor-2 (VIPR2) peptide agonist, LBT-3627, was developed as a neuroprotectant for PD-associated dopaminergic neurodegeneration. Employing both 6-hydroxydopamine (6-OHDA) and α-synuclein (α-Syn) overexpression models in rats, the sequential administration of LBT-3627 increased Treg activity without altering cell numbers both in naïve animals and during progressive nigrostriatal degeneration. LBT-3627 administration was linked to reductions of inflammatory microglia, increased survival of dopaminergic neurons, and improved striatal densities. While α-Syn overexpression resulted in reduced Treg activity, LBT-3627 rescued these functional deficits. This occurred in a dose-dependent manner closely mimicking neuroprotection. Taken together, these data provide the basis for the use of VIPR2 agonists as potent therapeutic immune modulating agents to restore Treg activity, attenuate neuroinflammation, and interdict dopaminergic neurodegeneration in PD. The data underscore an important role of immunity in PD pathogenesis.

Activation of Resolution Pathways to Prevent and Fight Chronic Inflammation: Lessons From Asthma and Inflammatory Bowel Disease

Formerly considered as a passive process, the resolution of acute inflammation is now recognized as an active host response, with a cascade of coordinated cellular and molecular events that promotes termination of the inflammatory response and initiates tissue repair and healing. In a state of immune fitness, the resolution of inflammation is contained in time and space enabling the restoration of tissue homeostasis. There is increasing evidence that poor and/or inappropriate resolution of inflammation participates in the pathogenesis of chronic inflammatory diseases, extending in time the actions of pro-inflammatory mechanisms, and responsible in the long run for excessive tissue damage and pathology. In this review, we will focus on how resolution can be the target for therapy in "Th1/Th17 cell-driven" immune diseases and "Th2 cell-driven" immune diseases, with inflammatory bowel diseases (IBD) and asthma, as relevant examples. We describe the main cells and mediators stimulating the resolution of inflammation and discuss how pharmacological and dietary interventions but also life style factors, physical and psychological conditions, might influence the resolution phase. A better understanding of the impact of endogenous and exogenous factors on the resolution of inflammation might open a whole area in the development of personalized therapies in non-resolving chronic inflammatory diseases.

Activation of Th lymphocytes alters pattern expression and cellular location of VIP receptors in healthy donors and early arthritis patients

Vasoactive Intestinal Peptide (VIP) is an important immunomodulator of CD4⁺ cells in normal and pathological conditions, which exerts its anti-inflammatory and immunomodulatory actions through VPAC receptors, VPAC₁ and VPAC₂. Only a decrease in the expression of VPAC₁ mRNA on Th cells upon activation has been reported. Thus, the deepening in the knowledge of the behavior of these receptors may contribute to the design of new therapies based on their activation and/or blockade. In this study, we describe the expression pattern, cellular location and functional role of VIP receptors during the activation of human Th cells in healthy conditions and in early arthritis (EA). The protein expression pattern of VPAC₁ did not change with the activation of Th lymphocytes, whereas VPAC₂ was up-regulated. In resting cells, VPAC₁ was located on the plasma membrane and nucleus, whereas it only appeared in the nucleus in activated cells. VPAC₂ was always found in plasma membrane location. VIP receptors signaled through a PKA-dependent pathway in both conditions, and also by a PKA-independent pathway in activated cells. Both receptors exhibit a potent immunomodulatory capacity by controlling the pathogenic profile and the activation markers of Th cells. These results highlight a novel translational view in inflammatory/autoimmune diseases.

Vasoactive intestinal peptide degradation might influence Interleukin-17 expression in cardiac chagasic patients

The vasoactive intestinal peptide (VIP) expression is lower in cardiac chagasic patients and is related to worse cardiac function. The reduction of VIP in patients with Chagas disease may be a result of its enhanced degradation. To test this hypothesis, the tryptase and chymase expression was evaluated. We also related VIP levels with interleukin-17 (IL-17) expression since VIP may modulate IL-17 production. Plasma levels of chymase were higher in chagasic patients. Conversely, VIP/chymase and VIP/tryptase ratios were lower in chagasic patients when compared to non-infected individuals. Besides, the VIP/chymase ratio was lower in chagasic cardiac patients in comparison with the indeterminate group. A positive correlation between tryptase and chymase levels was observed in chagasic cardiac patients. In relation to IL-17, we observed a higher expression of this cytokine in the cardiac form of the disease than in the indeterminate form. IL-17/VIP ratio was higher in the cardiac form in comparison with non-infected or indeterminate form. These results suggest that the low levels of VIP observed in chagasic patients could be due to an increased production of chymase and/or to the additive effect of the interaction between chymase and tryptase in the cardiac form. Moreover, the decreased VIP expression may contribute to the increase of IL-17 in chagasic cardiac patients.

Neuroendocrine cells derived chemokine vasoactive intestinal polypeptide (VIP) in allergic diseases

Worldwide increase incidences of allergic diseases have heightened the interest of clinicians and researchers to understand the role of neuroendocrine cells in the recruitment and activation of inflammatory cells. Several pieces of evidence revealed the association of neuropeptides in the pathogenesis of allergic diseases. Importantly, one such peptide that is secreted by neuronal cells and immune cells exerts a wide spectrum of immunological functions as cytokine/chemokine is termed as Vasoactive Intestinal Peptide (VIP). VIP mediates immunological function through interaction with specific receptors namely VPAC-1, VPAC-2, CRTH2 and PAC1 that are expressed on several immune cells such as eosinophils, mast cells, neutrophils, and lymphocytes; therefore, provide the basis for the action of VIP on the immune system. Additionally, VIP mediated action varies according to target organ depending upon the presence of specific VIP associated receptor, involved immune cells and the microenvironment of the organ. Herein, we present an integrative review of the current understanding on the role of VIP and associated receptors in allergic diseases, the presence of VIP receptors on various immune cells with particular emphasis on the role of VIP in the pathogenesis of allergic diseases such as asthma, allergic rhinitis, and atopic dermatitis. Being crucial signal molecule of the neuroendocrine-immune network, the development of stable VIP analogue and/or antagonist may provide the future therapeutic drug alternative for the better treatment of these allergic diseases. Taken together, our current review summarizes the current understandings of VIP biology and further explore the significance of neuroendocrine cells derived VIP in the recruitment of inflammatory cells in allergic diseases that may be helpful to the investigators for planning the experiments and accordingly predicting new therapeutic strategies for combating allergic diseases. Summarized graphical abstract will help the readers to understand the significance of VIP in allergic diseases.

VIP impairs acquisition of the macrophage proinflammatory polarization profile

This study tested the hypothesis that vasoactive intestinal peptide (VIP) is able to modify the macrophage inflammatory profile, thus supporting its therapeutic role in autoimmune diseases. Macrophages are innate immune cells that display a variety of functions and inflammatory profiles in response to the environment that critically controls their polarization. Deregulation between the pro- and anti-inflammatory phenotypes has been involved in different pathologies. Rheumatoid arthritis (RA) is an autoimmune disease, in which macrophages are considered central effectors of synovial inflammation, displaying a proinflammatory profile. VIP is a pleiotropic neuropeptide with proven anti-inflammatory actions. As modulation of the macrophage phenotype has been implicated in the resolution of inflammatory diseases, we evaluated whether VIP is able to modulate human macrophage polarization. In vitro-polarized macrophages by GM-CSF (GM-MØ), with a proinflammatory profile, expressed higher levels of VIP receptors, vasoactive intestinal polypeptide receptors 1 and 2 (VPAC1 and VPAC2, respectively), than macrophages polarized by M-CSF (M-MØ) with anti-inflammatory activities. RA synovial macrophages, according to their GM-CSF-like polarization state, expressed both VPAC1 and VPAC2. In vitro-generated GM-MØ exposed to VIP exhibited an up-regulation of M-MØ gene marker expression, whereas their proinflammatory cytokine profile was reduced in favor of an anti-inflammatory function. Likewise, in GM-MØ, generated in the presence of VIP, VIP somehow changes the macrophages physiology profile to a less-damaging phenotype. Therefore, these results add new value to VIP as an immunomodulatory agent on inflammatory diseases.

Neuroimmunity: Physiology and Pathology

Evolution has yielded multiple complex and complementary mechanisms to detect environmental danger and protect tissues from damage. The nervous system rapidly processes information and coordinates complex defense behaviors, and the immune system eliminates diverse threats by virtue of mobile, specialized cell populations. The two systems are tightly integrated, cooperating in local and systemic reflexes that restore homeostasis in response to tissue injury and infection. They further share a broad common language of cytokines, growth factors, and neuropeptides that enables bidirectional communication. However, this reciprocal cross talk permits amplification of maladaptive feedforward inflammatory loops that contribute to the development of allergy, autoimmunity, itch, and pain. Appreciating the immune and nervous systems as a holistic, coordinated defense system provides both new insights into inflammation and exciting opportunities for managing acute and chronic inflammatory diseases.

Decoding the chemokine network that links leukocytes with decidual cells and the trophoblast during early implantation

Chemokine network is central to the innate and adaptive immunity and entails a variety of proteins and membrane receptors that control physiological processes such as wound healing, angiogenesis, embryo growth and development. During early pregnancy, the chemokine network coordinates not only the recruitment of different leukocyte populations to generate the maternal-placental interface, but also constitutes an additional checkpoint for tissue homeostasis maintenance. The normal switch from a pro-inflammatory to an anti-inflammatory predominant microenvironment characteristic of the post-implantation stage requires redundant immune tolerance circuits triggered by key master regulators. In this review we will focus on the recruitment and conditioning of maternal immune cells to the uterus at the early implantation period with special interest on high plasticity macrophages and dendritic cells and their ability to induce regulatory T cells. We will also point to putative immunomodulatory polypeptides involved in immune homeostasis maintenance at the maternal-placental interface.

VIP treatment prevents embryo resorption by modulating efferocytosis and activation profile of maternal macrophages in the CBAxDBA resorption prone model

Successful embryo implantation occurs followed by a local pro-inflammatory response subsequently shifted toward a tolerogenic one. VIP (vasoactive intestinal peptide) has embryotrofic, anti-inflammatory and tolerogenic effects. In this sense, we investigated whether the in vivo treatment with VIP contributes to an immunosuppressant local microenvironment associated with an improved pregnancy outcome in the CBA/J × DBA/2 resorption prone model. Pregnancy induced the expression of VIP, VPAC1 and VPAC2 in the uterus from CBA/J × DBA/2 mating females on day 8.5 of gestation compared with non-pregnant mice. VIP treatment (2 nmol/mouse i.p.) on day 6.5 significantly increased the number of viable implantation sites and improved the asymmetric distribution of implanted embryos. This effect was accompanied by a decrease in RORγt and an increase in TGF-β and PPARγ expression at the implantation sites. Moreover, VIP modulated the maternal peritoneal macrophages efferocytosis ability, tested using latex beads-FITC or apoptotic thymocytes, displaying an increased frequency of IL-10-producer F4/80 cells while did not modulate TNF-α and IL-12 secretion. The present data suggest that VIP treatment increases the number of viable embryos associated with an increase in the efferocytic ability of maternal macrophages which is related to an immunosuppressant microenvironment.

Electroacupuncture Attenuates Collagen-Induced Arthritis in Rats through Vasoactive Intestinal Peptide Signalling-Dependent Re-Establishment of the Regulatory T Cell/T-Helper 17 Cell Balance

Objective

Imbalance between T-helper 17 (Th17) cells and regulatory T (Treg) cells is causally linked to the development of rheumatoid arthritis (RA). In this study, we tested the hypothesis that electroacupuncture (EA) confers therapeutic benefits in RA through activation of vasoactive intestinal peptide (VIP)-dependent signalling and restoration of the Th17/Treg cell balance.

Materials and Methods

A collagen-induced arthritis (CIA) model was induced in Sprague–Dawley rats by injection of bovine type II collagen in incomplete Freund's adjuvant on day 0 and day 7. Three days after the second injection, EA was given at acupuncture points GB39 and ST36 three times per week for 4 weeks. To block VIP signalling, [D-P-Cl-Phe(6)-Leu(17)]-VIP, a VIP receptor antagonist, was administered intraperitoneally 30 min before EA. Inflammatory and pathological responses in the joint were assessed. Synovial VIP receptor mRNA levels and Treg and Th17 cell frequencies in the spleen were determined.

Results

EA significantly reduced the severity of CIA, as evidenced by reduced paw volumes, arthritis scores and inflammation scores. EA significantly increased mRNA expression of the VIP receptor VPAC1 and led to an elevation in CD4+FOXP3+ Treg cell frequency and a reduction in CD4+IL17+ Th17 cell frequency. Pre-injection of a VIP receptor antagonist significantly reversed EA-induced expansion of Treg cells, but did not alter the frequencies of Th17 cells.

Conclusions

EA exerts anti-inflammatory effects in a collagen-induced rat model of arthritis. These effects appear to be mediated through activation of VIP signalling and re-establishment of the Th17/Treg cell balance.

Th17 polarization of memory Th cells in early arthritis: the vasoactive intestinal peptide effect

Several studies in humans indicate the implication of Th17 cells in RA. Therapies targeting their pathogenicity, as well as their plasticity to the Th17/1 phenotype, could ameliorate the progression of the pathology. The neuroendocrine environment has a major impact on the differentiation of lymphoid cells. VIP is present in the microenvironment of the joint, and its known therapeutic effects are supported by several studies on RA. We examine the ability of VIP to modulate the differentiation of Th17 cells. Peripheral blood CD4(+)CD45RO(+) T cells from HD and eRA patients were expanded under Th17-polarizing conditions in the presence of TGF-β. After 7 days, the higher IL-17A, IL-21, and IL-9 levels and lower IL-22 levels indicate the nonpathogenic profile for Th17 cells in HD. In contrast, Th17 cells from eRA patients produced significantly more IL-22 and IFN-γ, and these cells show a more Th17/1 profile, indicating a pathogenic phenotype. Interestingly, when VIP was present in the Th17 conditioned medium, increased levels of IL-10 and IL-9 were detected in HD and eRA patients. VIP also reduced the levels of IL-22 in eRA patients. These data suggest that VIP reduces the pathogenic profile of the Th17-polarized cells. This effect was accompanied by an increased in the Treg/Th17 profile, as shown by the increase levels of Foxp3. In conclusion, this report addresses a novel and interesting question on the effect of VIP on human Th17 cells and adds clinical relevance by analyzing, in parallel, HD and eRA patients.

S100A4-neutralizing antibody suppresses spontaneous tumor progression, pre-metastatic niche formation and alters T-cell polarization balance

Background

The tumor microenvironment plays a determinative role in stimulating tumor progression and metastasis. Notably, tumor-stroma signals affect the pattern of infiltrated immune cells and the profile of tumor-released cytokines. Among the known molecules that are engaged in stimulating the metastatic spread of tumor cells is the S100A4 protein. S100A4 is known as an inducer of inflammatory processes and has been shown to attract T-cells to the primary tumor and to the pre-metastatic niche. The present study aims to examine the immunomodulatory role of S100A4 in vivo and in vitro and assess the mode of action of 6B12, a S100A4 neutralizing antibody.

Methods

The therapeutic effect of the 6B12 antibody was evaluated in two different mouse models. First, in a model of spontaneous breast cancer we assessed the dynamics of tumor growth and metastasis. Second, in a model of metastatic niche formation we determined the expression of metastatic niche markers. The levels of cytokine expression were assessed using antibody as well as PCR arrays and the results confirmed by qRT-PCR and ELISA. T-cell phenotyping and in vitro differentiation analyses were performed by flow cytometry.

Results

We show that the S100A4 protein alters the expression of transcription factor and signal transduction pathway genes involved in the T-cell lineage differentiation. T-cells challenged with S100A4 demonstrated reduced proportion of Th1-polarized cells shifting the Th1/Th2 balance towards the Th2 pro-tumorigenic phenotype. The 6B12 antibody restored the Th1/Th2 balance. Furthermore, we provide evidence that the 6B12 antibody deploys its anti-metastatic effect, by suppressing the attraction of T-cells to the site of primary tumor and pre-metastatic niche. This was associated with delayed primary tumor growth, decreased vessel density and inhibition of metastases.

Conclusion

The S100A4 blocking antibody (6B12) reduces tumor growth and metastasis in a model of spontaneous breast cancer. The 6B12 antibody treatment inhibits T cell accumulation at the primary and pre-metastatic tumor sites. The 6B12 antibody acts as an immunomodulatory agent and thus supports the view that the 6B12 antibody is a promising therapeutic candidate to fight cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1034-2) contains supplementary material, which is available to authorized users.

The pathogenic Th profile of human activated memory Th cells in early rheumatoid arthritis can be modulated by VIP

Our aim is to study the behavior of memory Th cells (Th17, Th17/1, and Th1 profiles) from early rheumatoid arthritis (eRA) patients after their in vitro activation/expansion to provide information about its contribution to RA chronicity. Moreover, we analyzed the potential involvement of vasoactive intestinal peptide (VIP) as an endogenous healing mediator. CD4(+)CD45RO(+) T cells from PBMCs of HD and eRA were activated/expanded in vitro in the presence/absence of VIP. FACS, ELISA, RT-PCR, and immunocytochemistry analyses were performed. An increase in CCR6(+)/RORC(+) cells and in RORC-proliferating cells and a decrease in T-bet-proliferating cells and T-bet(+)/RORC(+) cells were shown in eRA. mRNA expression of IL-17, IL-2, RORC, RORA, STAT3, and Tbx21 and protein secretion of IL-17, IFNγ, and GM-CSF were higher in eRA. VIP decreased the mRNA expression of IL-22, IL-2, STAT3, Tbx21, IL-12Rβ2, IL-23R, and IL-21R in HD and it decreased IL-21, IL-2, and STAT3 in eRA. VIP decreased IL-22 and GM-CSF secretion and increased IL-9 secretion in HD and it decreased IL-21 secretion in eRA. VPAC2/VPAC1 ratio expression was increased in eRA. All in all, memory Th cells from eRA patients show a greater proportion of Th17 cells with a pathogenic Th17 and Th17/1 profile compared to HD. VIP is able to modulate the pathogenic profile, mostly in HD. Our results are promising for therapy in the early stages of RA because they suggest that targeting molecules involved in the pathogenic Th17, Th17/1, and Th1 phenotypes and targeting VIP receptors could have a therapeutic effect modulating these subsets.

KEY MESSAGES

Th17 cells are more important than Th1 in the contribution to pathogenesis in eRA patients. Pathogenic Th17 and Th17/1 profile are abundant in activated/expanded memory Th cells from eRA patients. VIP decreases the pathogenic Th17, Th1, and Th17/1 profiles, mainly in healthy donors. The expression of VIP receptors is reduced in eRA patients respect to healthy donors, whereas the ratio of VPAC2/VPAC1 expression is higher.

Vasoactive intestinal peptide maintains the nonpathogenic profile of human th17-polarized cells

The cytokine microenvironment modulates CD4 T cell differentiation causing the shift of naïve CD4 T cells into different cell subsets. This process is also regulated by modulators such as vasoactive intestinal peptide (VIP), a neuropeptide with known immunomodulatory properties on CD4 T cells that exert this action through specific receptors, vasoactive intestinal peptide receptor (VPAC)1 and VPAC2. Our results show that the pattern of VIP receptors expression ratio is modified during Th17 differentiation. In this report, we evaluate the capacity of VIP to modulate naïve human cells into Th17 cells in vitro by analyzing their functional phenotype. The presence of VIP maintains the nonpathogenic profile of Th17-polarized cells, increases the proliferation rate, and decreases their Th1 potential. VIP induces the upregulation of the STAT3 gene interaction with the VPAC1 receptor during the onset of Th17 differentiation. Moreover, RAR-related orphan receptor C (RORC), RAR-related orphan receptor A (RORA), and interleukin (IL)-17A genes are upregulated in the presence of VIP through interaction with VPAC1 and VPAC2 receptors. Interestingly, VIP induces the expression of the IL-23R gene through interaction with the VPAC2 receptor during the expansion phase. This is the first report that describes the differentiation of naïve human T cells to Th17-polarized cells in the presence of VIP and demonstrates how this differentiation regulates the expression of the VIP receptors.

Tolerance induction at the early maternal-placental interface through selective cell recruitment and targeting by immune polypeptides

Pregnancy challenges immune cells and immunomodulatory circuits of the mother and the developing fetus to dynamically adapt to each other in an homeostatic and tolerant environment for fetal growth. This entails the coordination of multiple cellular processes all devoted to accommodate and nourish the fetus while protecting the mother from endogenous and exogenous threatens. From the earliest stages of pregnancy, several strategies to efficiently communicate immune and trophoblast cells within the interface or at a distance were identified and chemokines might act at on different targets through direct or indirect mechanisms. Here, we briefly review some mechanisms of T regulatory cell recruitment to the early maternal-placental interfaces to accomplish immunotolerance and homeostatic control and we discuss evidence on two locally released polypeptides, RANTES (regulated on activation, normal, T-cell expressed, and secreted) and vasoactive intestinal peptide (VIP), as novel contributors to the multiplicity of immune tolerant responses and uterine quiescence requirements.

Novel, biocompatible, and disease modifying VIP nanomedicine for rheumatoid arthritis

Despite advances in rheumatoid arthritis (RA) treatment, efficacious and safe disease-modifying therapy still represents an unmet medical need. Here, we describe an innovative strategy to treat RA by targeting low doses of vasoactive intestinal peptide (VIP) self-associated with sterically stabilized micelles (SSMs). This spontaneous interaction of VIP with SSM protects the peptide from degradation or inactivation in biological fluids and prolongs circulation half-life. Treatment with targeted low doses of nanosized SSM-VIP but not free VIP in buffer significantly reduced the incidence and severity of arthritis in an experimental model, completely abrogating joint swelling and destruction of cartilage and bone. In addition, SSM associated VIP, unlike free VIP, had no side-effects on the systemic functions due to selective targeting to inflamed joints. Finally, low doses of VIP in SSM successfully downregulated both inflammatory and autoimmune components of RA. Collectively, our data clearly indicate that VIP-SSM should be developed to be used as a novel nanomedicine for the treatment of RA.

CD4(+)CD25(+)Foxp3(+)IFNγ(+) Treg are immunosuppressive in vitro and increase with intensity of the alloresponse in pretransplant MLC

IFNγ-producing CD3(+)CD4(+)CD25(+)Foxp3(+) induced Treg are more frequently detectable in patients with good than in patients with impaired long-term kidney graft function. We investigated the in-vitro function of separated CD3(+)CD4(+)CD25(+)Foxp3(+)IFNγ(+) PBL that were induced by phorbol-12-myristate-13-acetate(PMA)/Ionomycin or alloantigenic stimulation. Additionally, we studied iTreg induction and cell proliferation in MLC with pretransplant obtained PBL. CD4(+)CD25(+)IFNγ(+) PBL separated from PMA/Ionomycin-stimulated PBL of healthy controls inhibited secondary cell cultures of autologous PBL. Furthermore, CD4(+)CD25(+)IFNγ(+) PBL separated from primary MLC and added to secondary MLC suppressed allogeneic T-cell activation in secondary MLC unspecifically, irrespective of the stimulator cell. However, the strongest suppression was observed in specific MLC. Patients with poor long-term graft outcome were able to form IFNγ(+) iTreg in pretransplant MLC. Eight patients with a serum creatinine level ranging from 0.9 to 14 mg/dl 18-29 years posttransplant were studied. In MLC with pretransplant obtained recipient and donor cells, strong IFNγ(+) iTreg (p=0.007) and strong blast induction (p=0.047) were associated with impaired long-term graft outcome. Long-term graft outcome was not associated with cell proliferation and iTreg induction in unspecific MLC with third-party cells as stimulator. The data indicate that patients with impaired long-term graft outcome are able to form high numbers of IFNγ(+) iTreg in specific pretransplant MLC. Quantity of induced IFNγ(+) iTreg depends on the strength of the alloresponse and both parameters are inversely associated with long-term graft outcome.

Neurogenic inflammation and the peripheral nervous system in host defense and immunopathology

The peripheral nervous and immune systems are traditionally thought of as serving separate functions. The line between them is, however, becoming increasingly blurred by new insights into neurogenic inflammation. Nociceptor neurons possess many of the same molecular recognition pathways for danger as immune cells, and, in response to danger, the peripheral nervous system directly communicates with the immune system, forming an integrated protective mechanism. The dense innervation network of sensory and autonomic fibers in peripheral tissues and high speed of neural transduction allows rapid local and systemic neurogenic modulation of immunity. Peripheral neurons also seem to contribute to immune dysfunction in autoimmune and allergic diseases. Therefore, understanding the coordinated interaction of peripheral neurons with immune cells may advance therapeutic approaches to increase host defense and suppress immunopathology.

VIP Regulates the Development & Proliferation of Treg in vivo in spleen

BACKGROUND

Mounting evidence supports a key role for VIP as an anti-inflammatory agent and promoter of immune tolerance. It suppresses TNF-α and other inflammatory cytokines and chemokines, upregulates anti-inflammatory IL-10, and promotes immune tolerant cells called T regulatory (Treg) cells. VIP KO mice have recently been demonstrated to have spontaneous airway and pulmonary perivascular inflammatory responses, as part of asthma-like and pulmonary hypertension phenotypes, respectively. Both inflammatory responses are correctable with VIP. Focusing on this model, we have now investigated the influence of VIP not only on inflammatory cells but also on Treg cells.

METHODS

Using flow cytometric analysis, we examined the relative preponderance of CD25+CD4+ cells and anti-inflammatory Treg cells, in extracts of thymus and spleen from VIP KO mice (5 VIP KO; 5 VIP KO+ VIP; 10 wild-type). This method allowed antibody-based flow cytometric identification of Treg cells using surface markers CD25 and CD4, along with the: 1) intracellular activation marker FoxP3; and 2) Helios, which distinguishes cells of thymic versus splenic derivation.

CONCLUSIONS

Deletion of the VIP gene results in: 1) CD25+CD4- cell accumulation in the thymus, which is corrected by VIP treatment; 2) more Treg in thymus lacking Foxp3 expression, suggesting VIP is necessary for immune tolerance; and, 3) a tendency towards deficiency of Treg cells in the spleen, which is normalized by VIP treatment. Treg lacking Helios are induced by VIP intrasplenically rather than by migration from the thymus. These results confirm the dual role of VIP as an anti-inflammatory and immune tolerance-promoting agent.