Langerhans cells beta 2-adrenoceptors: role in migration, cytokine production, Th priming and contact hypersensitivity

Neurobiology of cancer: Adrenergic signaling and drug repurposing

Cancer neuroscience, as an emerging converging discipline, provides us with new perspectives on the interactions between the nervous system and cancer progression. As the sympathetic nervous system, in particular adrenergic signaling, plays an important role in the regulation of tumor activity at every hierarchical level of life, from the tumor cell to the tumor microenvironment, and to the tumor macroenvironment, it is highly desirable to dissect its effects. Considering the far-reaching implications of drug repurposing for antitumor drug development, such a large number of adrenergic receptor antagonists on the market has great potential as one of the means of antitumor therapy, either as primary or adjuvant therapy. Therefore, this review aims to summarize the impact of adrenergic signaling on cancer development and to assess the status and prospects of intervening in adrenergic signaling as a therapeutic tool against tumors.

Effects of chronic stress on cancer development and the therapeutic prospects of adrenergic signaling regulation

Long-term chronic stress is an important factor in the poor prognosis of cancer patients. Chronic stress reduces the tissue infiltration of immune cells in the tumor microenvironment (TME) by continuously activating the adrenergic signaling, inhibits antitumor immune response and tumor cell apoptosis while also inducing epithelial-mesenchymal transition (EMT) and tumor angiogenesis, promoting tumor invasion and metastasis. This review first summarizes how adrenergic signaling activates intracellular signaling by binding different adrenergic receptor (AR) heterodimers. Then, we focused on reviewing adrenergic signaling to regulate multiple functions of immune cells, including cell differentiation, migration, and cytokine secretion. In addition, the article discusses the mechanisms by which adrenergic signaling exerts pro-tumorigenic effects by acting directly on the tumor itself. It also highlights the use of adrenergic receptor modulators in cancer therapy, with particular emphasis on their potential role in immunotherapy. Finally, the article reviews the beneficial effects of stress intervention measures on cancer treatment. We think that enhancing the body's antitumor response by adjusting adrenergic signaling can enhance the efficacy of cancer treatment.

Immunomodulatory chitosan nanoparticles for Toxoplasma gondii infection: Novel application of chitosan in complex propranolol-hydrochloride as an adjuvant in vaccine delivery

The study aimed to investigate the immunomodulatory effects of propranolol hydrochloride (PRO) in combination with chitosan nanoparticles (CS NPs) as an adjuvant to develop an effective vaccine against T. gondii. A total of 105 BALB/c mice were randomly divided into seven equal groups including PBS alone, CS NPs, SAG1 (Surface antigen 1), CS-SAG1 NPs, CS-PRO NPs, SAG1-PRO, and CS-SAG1-PRO NPs. The immunostimulatory effect of each adjuvant used for vaccine delivery was evaluated in a mice immunization model. The results showed that the mice immunized with CS-SAG1-PRO NPs exhibited the highest lymphocyte proliferation rate, along with increased secretion of IFN-γ, TNF-α, IL-6, IL-12, IL-17, and IL-23, as well as elevated levels of protective cytokines such as TGF-β, IL-27, and IL-10. Although, the CS-SAG1-PRO NPs immunized mice showed the highest level of T. gondii specific IgG compared to the other groups, a significant production of IgG2a and IgG1 was observed in the sera of mice immunized with the CS-SAG1-PRO NPs compared to the other group (p <0.001). The higher IgG2a/IgG1 ratio observed in the CS-SAG1-PRO NPs group indicates a bias towards Th1 cell polarization, suggesting the promotion of Th1 cell-mediated immune responses. Considering the combination of the highest lymphocyte proliferation and survival rates, IgG2a/IgG1 ratio, and cytokine levels in the mice immunized with CS-SAG1-PRO NPs, this approach holds promise for immunostimulation and vaccine delivery against T. gondii infection.

Tolerogenic phenotype of dendritic cells is induced after hapten sensitization followed by attenuated contact hypersensitivity response in atopic dermatitis model NC/Nga mice

Allergic contact dermatitis (ACD) and atopic dermatitis (AD) are common inflammatory diseases. We previously reported attenuated contact hypersensitivity (CHS) responses in AD model mice using 2,4-dinitrofluorobenzene, reflecting clinical experiments. However, previous studies have not addressed the commonality of findings across haptens and mechanisms focused on dendritic cells (DCs). Thus, this study evaluated CHS responses to fluorescein isothiocyanate (FITC) and DC migration and maturation in the sensitization phase of CHS in AD. CHS responses to FITC were compared between NC/Nga mice without and with AD induction (non-AD and AD mice, respectively). T-cell responses and DC migration and maturation after FITC-induced sensitization were examined in the draining lymph nodes of non-AD and AD mice. AD mice demonstrated reduced CHS responses to FITC under decreased T-cell proliferation following sensitization and interferon-γ production by hapten-specific T cells compared with non-AD mice. In addition, the number of FITC+CD11c+MHC class IIhigh migratory DCs 24 h after FITC sensitization was comparable between non-AD and AD mice. However, FITC+CD11c+MHC class IIhigh migratory DCs in AD mice exhibited lower expression levels of CD80 and CD86 and higher expression levels of PD-L1 and mRNA of transforming growth factor beta than non-AD mice. These findings suggest that attenuated CHS responses may be hapten-independent and the induction of the tolerogenic phenotype of hapten-bearing DCs can contribute to reduced T-cell proliferation after sensitization and CHS responses in AD.

CTLA-4 suppresses hapten-induced contact hypersensitivity in atopic dermatitis model mice

Atopic dermatitis (AD) patients with skin barrier dysfunction are considered to be at a higher risk of allergic contact dermatitis (ACD), although previous studies showed that attenuated ACD responses to strong sensitizers in AD patients compared to healthy controls. However, the mechanisms of ACD response attenuation in AD patients are unclear. Therefore, using the contact hypersensitivity (CHS) mouse model, this study explored the differences in CHS responses to hapten sensitization between NC/Nga mice with or without AD induction (i.e., non-AD and AD mice, respectively). In this study, ear swelling and hapten-specific T cell proliferation were significantly lower in AD than in non-AD mice. Moreover, we examined the T cells expressing cytotoxic T lymphocyte antigen-4 (CTLA-4), which is known to suppress T cell activation, and found a higher frequency of CTLA-4⁺ regulatory T cells in draining lymph node cells in AD than in non-AD mice. Furthermore, the blockade of CTLA-4 using a monoclonal antibody eliminated the difference in ear swelling between non-AD and AD mice. These findings suggested that CTLA-4⁺T cells may contribute to suppressing the CHS responses in AD mice.

Adrenergic receptor signaling regulates the CD40-receptor mediated anti-tumor immunity

Inroduction

Anti-CD40 agonistic antibody (αCD40), an activator of dendritic cells (DC) can enhance antigen presentation and activate cytotoxic T-cells against poorly immunogenic tumors. However, cancer immunotherapy trials also suggest that αCD40 is only moderately effective in patients, falling short of achieving clinical success. Identifying factors that decrease αCD40 immune-stimulating effects can aid the translation of this agent to clinical reality.

Method/Results

Here, we reveal that β-adrenergic signaling on DCs directly interferes with αCD40 efficacy in immunologically cold head and neck tumor model. We discovered that β-2 adrenergic receptor (β2AR) activation rewires CD40 signaling in DCs by directly inhibiting the phosphorylation of IκBα and indirectly by upregulating levels of phosphorylated-cAMP response element-binding protein (pCREB). Importantly, the addition of propranolol, a pan β-Blocker reprograms the CD40 pathways, inducing superior tumor regressions, increased infiltration of cytotoxic T-cells, and a reduced burden of regulatory T-cells in tumors compared to monotherapy.

Discussion/Conclusion

Thus, our study highlights an important mechanistic link between stress-induced β2AR signaling and reduced αCD40 efficacy in cold tumors, providing a new combinatorial approach to improve clinical outcomes in patients.

The diversity of neuroimmune circuits controlling lung inflammation

It is becoming increasingly appreciated that the nervous and immune systems communicate bidirectionally to regulate immunological outcomes in a variety of organs including the lung. Activation of neuronal signaling can be induced by inflammation, tissue damage, or pathogens to evoke or reduce immune cell activation in what has been termed a neuroimmune reflex. In the periphery, these reflexes include the cholinergic anti-inflammatory pathway, sympathetic reflex, and sensory nociceptor-immune cell pathways. Continual advances in neuroimmunology in peripheral organ systems have fueled small-scale clinical trials that have yielded encouraging results for a range of immunopathologies such as rheumatoid arthritis. Despite these successes, several limitations should give clinical investigators pause in the application of neural stimulation as a therapeutic for lung inflammation, especially if inflammation arises from a novel pathogen. In this review, the general mechanisms of each reflex, the evidence for these circuits in the control of lung inflammation, and the key knowledge gaps in our understanding of these neuroimmune circuits will be discussed. These limitations can be overcome not only through a better understanding of neuroanatomy but also through a systematic evaluation of stimulation parameters using immune activation in lung tissues as primary readouts. Our rapidly evolving understanding of the nervous and immune systems highlights the importance of communication between these cells in health and disease. This integrative approach has tremendous potential in the development of targeted therapeutics if specific challenges can be overcome.

Neuronal regulation of B-cell immunity: Anticipatory immune posturing?

The brain may sense, evaluate, modulate, and intervene in the operation of immune system, which would otherwise function autonomously in defense against pathogens. Antibody-mediated immunity is one arm of adaptive immunity that may achieve sterilizing protection against infection. Lymphoid organs are densely innervated. Immune cells supporting the antigen-specific antibody response express receptors for neurotransmitters and glucocorticoid hormones, and they are subjected to collective regulation by the neuroendocrine and the autonomic nervous system. Emerging evidence reveals a brain-spleen axis that regulates antigen-specific B cell responses and antibody-mediated immunity. In this article, we provide a synthesis of those studies as pertinent to neuronal regulation of B cell responses in secondary lymphoid organs. We propose the concept of defensive immune posturing as a brain-initiated top-down reaction in anticipation of potential tissue injury that requires immune protection.

Stress and cancer: The mechanisms of immune dysregulation and management

Advances in the understanding of psychoneuroimmunology in the past decade have emphasized the notion that stress and cancer are interlinked closely. Durable chronic stress accelerated tumorigenesis and progression, which is unfavorable for clinical outcomes of cancer patients. Available evidence has provided unprecedented knowledge about the role and mechanisms of chronic stress in carcinogenesis, the most well-known one is dysfunction of the hypothalamus-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS). With abnormal activation of neuroendocrine system, stress-related hormones contribute to increased oncogenes expression, exacerbated chronic inflammation and impaired immunologic function. In addition, accumulating studies have demonstrated that diverse stress interventions including pharmacological approaches, physical exercises and psychological relaxation have been administered to assist in mental disorders reduction and life quality improvement in cancer patients. In this review, we systematically summarize the connection and mechanisms in the stress-immune-cancer axis identified by animal and clinical studies, as well as conclude the effectiveness and deficiencies of existing stress management strategies.

Interactions between the Autonomic Nervous System and the Immune System after Stroke

Acute stroke is one of the leading causes of morbidity and mortality worldwide. Stroke-induced immune-inflammatory response occurs in the perilesion areas and the periphery. Although stroke-induced immunosuppression may alleviate brain injury, it hinders brain repair as the immune-inflammatory response plays a bidirectional role after acute stroke. Furthermore, suppression of the systemic immune-inflammatory response increases the risk of life-threatening systemic bacterial infections after acute stroke. Therefore, it is essential to explore the mechanisms that underlie the stroke-induced immune-inflammatory response. Autonomic nervous system (ANS) activation is critical for regulating the local and systemic immune-inflammatory responses and may influence the prognosis of acute stroke. We review the changes in the sympathetic and parasympathetic nervous systems and their influence on the immune-inflammatory response after stroke. Importantly, this article summarizes the mechanisms on how ANS regulates the immune-inflammatory response through neurotransmitters and their receptors in immunocytes and immune organs after stroke. To facilitate translational research, we also discuss the promising therapeutic approaches modulating the activation of the ANS or the immune-inflammatory response to promote neurologic recovery after stroke. © 2022 American Physiological Society. Compr Physiol 12:3665-3704, 2022.

Tumor regionalization after surgery: Roles of the tumor microenvironment and neutrophil extracellular traps

Surgery is unanimously regarded as the primary strategy to cure solid tumors in the early stages but is not always used in advanced cases. However, tumor surgery must be carefully considered because the risk of metastasis could be increased by the surgical procedure. Tumor surgery may result in a deep wound, which induces many biological responses favoring tumor metastasis. In particular, NETosis, which is the process of forming neutrophil extracellular traps (NETs), has received attention as a risk factor for surgery-induced metastasis. To reduce cancer mortality, researchers have made efforts to prevent secondary metastasis after resection of the primary tumor. From this point of view, a better understanding of surgery-induced metastasis might provide new strategies for more effective and safer surgical approaches. In this paper, recent insights into the surgical effects on metastasis will be reviewed. Moreover, in-depth opinions about the effects of NETs on metastasis will be discussed.

Therapies that limit the formation of web-like structures formed by white cells known as neutrophils may lower the risk of cancer spread (metastasis) following surgical tumor removal. Removing solid tumors remains a key cancer treatment, but in some cases surgery itself increases the risk of metastasis. Jong-Wan Park at Seoul National University, South Korea, and co-workers reviewed current understanding of metastasis following surgery. Surgical removal destroys the architecture supporting cancer cells but this can release tumor cells into blood vessels. The stress of deep wounds also affects immune responses, most notably neutrophil extracellular traps (NETs), web-like structures formed by neutrophils to trap and kill pathogens. NETs have previously been implicated in metastasis. In a post-surgical environment enriched in neutrophils and pro-inflammatory cytokines, NET formation may help cancer cells thrive, promoting metastasis.

Somatosensory and autonomic neuronal regulation of the immune response

Bidirectional communication between the peripheral nervous system (PNS) and the immune system is a crucial part of an effective but balanced mammalian response to invading pathogens, tissue damage and inflammatory stimuli. Here, we review how somatosensory and autonomic neurons regulate immune cellular responses at barrier tissues and in peripheral organs. Immune cells express receptors for neuronal mediators, including neuropeptides and neurotransmitters, allowing neurons to influence their function in acute and chronic inflammatory diseases. Distinct subsets of peripheral sensory, sympathetic, parasympathetic and enteric neurons are able to signal to innate and adaptive immune cells to modulate their cellular functions. In this Review, we highlight recent studies defining the molecular mechanisms by which neuroimmune signalling mediates tissue homeostasis and pathology. Understanding the neural circuitry that regulates immune responses can offer novel targets for the treatment of a wide array of diseases.

Psychosocial stress and immunosuppression in cancer: what can we learn from new research?

It is generally believed that the physiological consequences of stress could contribute to poor outcomes for patients being treated for cancer. However, despite preclinical and clinical evidence suggesting that stress promotes increased cancer-related mortality, a comprehensive understanding of the mechanisms involved in mediating these effects does not yet exist. We reviewed 47 clinical studies published between 2007 and 2020 to determine whether psychosocial stress affects clinical outcomes in cancer: 6.4% of studies showed a protective effect; 44.6% showed a harmful effect; 48.9% showed no association. These data suggest that psychosocial stress could affect cancer incidence and/or mortality, but the association is unclear. To shed light on this potentially important relationship, objective biomarkers of stress are needed to more accurately evaluate levels of stress and its downstream effects. As a potential candidate, the neuroendocrine signalling pathways initiated by stress are known to affect anti-tumour immune cells, and here we summarise how this may promote an immunosuppressive, pro-tumour microenvironment. Further research must be done to understand the relationships between stress and immunity to more accurately measure how stress affects cancer progression and outcome.

Melatonin administration provokes the activity of dendritic reticular cells in the seminal vesicle of Soay ram during the non-breeding season

Dendritic cells (DCs) are innate immune cells which engulf, process and present antigens to the naïve T-lymphocyte cells. However, little is known about the effect of melatonin on the DCs. The present study aimed to investigate the morphology and distribution of the DCs by transmission electron microscopy and Immunohistochemistry after melatonin administration. A total of 8 out of 15 adult ram was randomly selected to receive the melatonin implant and the remaining 7 animals received melatonin free implants. DCs showed positive immunoreactivity for CD117, S-100 protein and CD34. There is an obvious increase in the number of the positive immunoreactive cells to CD3, estrogen receptor alpha and progesterone in the treated groups. The expression of CD56 and MHCII in the DCs was abundant in the treated groups. The ultrastructure study revealed that melatonin exerts a stimulatory effect on the DCs which was associated with increment in the secretory activity of DCs. The secretory activity demarcated by an obvious increase in the number of mitochondria, cisternae of rER and a well-developed Golgi apparatus. The endosomal- lysosomal system was more developed in the treated groups. A rod-shaped Birbeck granule was demonstrated in the cytoplasm of the melatonin treated group. DCs were observed in a close contact to telocytes, T-Lymphocytes, nerve fibers and blood vessels. Taken together, melatonin administration elicits a stimulatory action on the DCs and macrophages through increasing the size, the number and the endosomal compartments which may correlate to increased immunity.

Role of adrenergic receptor signalling in neuroimmune communication

Neuroimmune communication plays a crucial role in maintaining homeostasis and promptly responding to any foreign insults. Sympathetic nerve fibres are innervated into all the lymphoid organs (bone marrow, thymus, spleen, and lymph nodes) and provide a communication link between the central nervous system (CNS) and ongoing immune response in the tissue microenvironment. Neurotransmitters such as catecholamines (epinephrine and norepinephrine) bind to adrenergic receptors present on most immune and non-immune cells, establish a local neuroimmune-communication system, and help regulate the ongoing immune response. The activation of these receptors varies with the type of receptor-activated, target cell, the activation status of the cells, and timing of activation. Activating adrenergic receptors, specifically β-adrenergic signalling in immune cells leads to activation of the cAMP-PKA pathway or other non-canonical pathways. It predominantly leads to immune suppression such as inhibition of IL-2 secretion and a decrease in macrophages phagocytosis. This review discusses the expression of different adrenergic receptors in various immune cells, signalling, and how it modulates immune cell function and contributes to health and diseases. Understanding the neuroimmune communication through adrenergic receptor signalling in immune cells could help to design better strategies to control inflammation and autoimmunity.

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Primary and secondary lymphoid organs are innervated with sympathetic nerve fibres.

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Adrenergic receptor expression on immune and non-immune cells establishes a local neuroimmune communication system.

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Adrenergic receptor signalling in immune cells controls the differentiation and function of various immune cells.

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Modulating adrenergic receptor signalling with a specific agonist or antagonist also affect the immune response.

Neuroendocrine Regulation of Tumor-Associated Immune Cells

Mounting preclinical and clinical evidence continues to support a role for the neuroendocrine system in the modulation of tumor biology and progression. Several studies have shown data supporting a link between chronic stress and cancer progression. Dysregulation of the sympathetic nervous system (SNS) and the hypothalamic-pituitary-adrenal (HPA) axis has been implicated in promoting angiogenesis, tumor cell proliferation and survival, alteration of the immune response and exacerbating inflammatory networks in the tumor microenvironment. Here, we review how SNS and HPA dysregulation contributes to disturbances in immune cell populations, modifies cancer biology, and impacts immunotherapy response. We also highlight several interventions aimed at circumventing the adverse effects stress has on cancer patients.

Toward the Existence of a Sympathetic Neuroplasticity Adaptive Mechanism Influencing the Immune Response. A Hypothetical View-Part II

In the preceding work, a hypothesis on the existence of a specific neural plasticity program from sympathetic fibers innervating secondary lymphoid organs was introduced. This proposed adaptive mechanism would involve segmental retraction and degeneration of noradrenergic terminals during the immune system (IS) activation followed by regeneration once the IS returns to the steady-state. Starting from such view, this second part presents clinical and experimental evidence allowing to envision that this sympathetic neural plasticity mechanism is also operative on inflamed non-lymphoid peripheral tissues. Importantly, the sympathetic nervous system regulates most of the physiological bodily functions, ranging from cardiovascular, respiratory and gastro-intestinal functions to endocrine and metabolic ones, among others. Thus, it seems sensible to think that compensatory programs should be put into place during inflammation in non-lymphoid tissues as well, to avoid the possible detrimental consequences of a sympathetic blockade. Nevertheless, in many pathological scenarios like severe sepsis, chronic inflammatory diseases, or maladaptive immune responses, such compensatory programs against noradrenergic transmission impairment would fail to develop. This would lead to a manifest sympathetic dysfunction in the above-mentioned settings, partly accounting for their underlying pathophysiological basis; which is also discussed. The physiological/teleological significance for the whole neural plasticity process is postulated, as well.

Stress, inflammation, and eicosanoids: an emerging perspective

Clinical and experimental studies support the notion that adrenergic stimulation and chronic stress affect inflammation, metabolism, and tumor growth. Eicosanoids are also known to heavily influence inflammation while regulating certain stress responses. However, additional work is needed to understand the full extent of interactions between the stress-related pathways and eicosanoids. Here, we review the potential influences that stress, inflammation, and metabolic pathways have on each other, in the context of eicosanoids. Understanding the intricacies of such interactions could provide insights on how systemic metabolic effects mediated by the stress pathways can be translated into therapies for cancer and other diseases.

Role of the End-Point Mediators of Sympathoadrenal and Sympathoneural Stress Axes in the Pathogenesis of Experimental Autoimmune Encephalomyelitis and Multiple Sclerosis

The role of stress effector systems in the initiation and progression of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), the most commonly used experimental model of MS, has strongly been suggested. To corroborate this notion, alterations in activity of the sympathoadrenal and sympathoneural axes of sympathoadrenal system (a major communication pathway between the central nervous system and the immune system), mirrored in altered release of their end-point mediators (adrenaline and noradrenaline, respectively), are shown to precede (in MS) and/or occur during development of MS and EAE in response to immune cell activation (in early phase of disease) and disease-related damage of sympathoadrenal system neurons and their projections (in late phase of disease). To add to the complexity, innate immunity cells and T-lymphocytes synthesize noradrenaline that may be implicated in a local autocrine/paracrine self-amplifying feed-forward loop to enhance myeloid-cell synthesis of proinflammatory cytokines and inflammatory injury. Furthermore, experimental manipulations targeting noradrenaline/adrenaline action are shown to influence clinical outcome of EAE, in a disease phase-specific manner. This is partly related to the fact that virtually all types of cells involved in the instigation and progression of autoimmune inflammation and target tissue damage in EAE/MS express functional adrenoceptors. Although catecholamines exert majority of immunomodulatory effects through β₂-adrenoceptor, a role for α-adrenoceptors in EAE pathogenesis has also been indicated. In this review, we summarize all aforementioned aspects of immunopathogenetic action of catecholamines in EAE/MS as possibly important for designing new strategies targeting their action to prevent/mitigate autoimmune neuroinflammation and tissue damage.

Propranolol efficacy as a novel adjuvant for immunization against Toxoplasma gondii tachyzoites

Severe or lethal damages, caused by Toxoplasma gondii infection in congenital cases and immunocompromised patients implies the necessity for development of a vaccine and an appropriate adjuvant would be needed to elicit a protective Th1 biased-immune response. The adjuvant activity of propranolol was surveyed and compared with alum by immunization of BALB/c mice with protein components of T. gondii tachyzoites. Five groups of BALB/c mice were immunized with phosphate buffered saline (negative control), Toxoplasma lysate antigen (TLA), alum plus TLA, Propranolol plus TLA, and alum, propranolol and TLA. Immunization efficacy was evaluated by lymphocyte proliferation and DTH tests, challenge with live tachyzoites, IFN-γ production by spleen cells, serum TNF-α concentration and anti- Toxoplasma total IgG, IgG1 and IgG2a measurements. Mice of the PRP-TLA group induced significantly more IFN-γ and TNF-α production and lymphocyte proliferation than other groups. This group of mice also showed more anti-T. gondii IgG2a and DTH responses and showed a significantly increased survival time after challenge. These findings indicate that propranolol as an adjuvant in combination with TLA, may enhance cellular immunity against T. gondii.

Functional neuroanatomy of peripheral inflammatory physiology: A meta-analysis of human neuroimaging studies

Communication between the brain and peripheral mediators of systemic inflammation is implicated in numerous psychological, behavioral, and physiological processes. Functional neuroimaging studies have identified brain regions that associate with peripheral inflammation in humans, yet there are open questions about the consistency, specificity, and network characteristics of these findings. The present systematic review provides a meta-analysis to address these questions. Multilevel kernel density analysis of 24 studies (37 statistical maps; 264 coordinates; 457 participants) revealed consistent effects in the amygdala, hippocampus, hypothalamus, striatum, insula, midbrain, and brainstem, as well as prefrontal and temporal cortices. Effects in some regions were specific to particular study designs and tasks. Spatial pattern analysis revealed significant overlap of reported effects with limbic, default mode, ventral attention, and corticostriatal networks, and co-activation analyses revealed functional ensembles encompassing the prefrontal cortex, insula, and midbrain/brainstem. Together, these results characterize brain regions and networks associated with peripheral inflammation in humans, and they provide a functional neuroanatomical reference point for future neuroimaging studies on brain-body interactions.

Adrenergic Signaling: A Targetable Checkpoint Limiting Development of the Antitumor Immune Response

An immune response must be tightly controlled so that it will be commensurate with the level of response needed to protect the organism without damaging normal tissue. The roles of cytokines and chemokines in orchestrating these processes are well known, but although stress has long been thought to also affect immune responses, the underlying mechanisms were not as well understood. Recently, the role of nerves and, specifically, the sympathetic nervous system, in regulating immune responses is being revealed. Generally, an acute stress response is beneficial but chronic stress is detrimental because it suppresses the activities of effector immune cells while increasing the activities of immunosuppressive cells. In this review, we first discuss the underlying biology of adrenergic signaling in cells of both the innate and adaptive immune system. We then focus on the effects of chronic adrenergic stress in promoting tumor growth, giving examples of effects on tumor cells and immune cells, explaining the methods commonly used to induce stress in preclinical mouse models. We highlight how this relates to our observations that mandated housing conditions impose baseline chronic stress on mouse models, which is sufficient to cause chronic immunosuppression. This problem is not commonly recognized, but it has been shown to impact conclusions of several studies of mouse physiology and mouse models of disease. Moreover, the fact that preclinical mouse models are chronically immunosuppressed has critical ramifications for analysis of any experiments with an immune component. Our group has found that reducing adrenergic stress by housing mice at thermoneutrality or treating mice housed at cooler temperatures with β-blockers reverses immunosuppression and significantly improves responses to checkpoint inhibitor immunotherapy. These observations are clinically relevant because there are numerous retrospective epidemiological studies concluding that cancer patients who were taking β-blockers have better outcomes. Clinical trials testing whether β-blockers can be repurposed to improve the efficacy of traditional and immunotherapies in patients are on the horizon.

Causal Neuro-immune Relationships at Patients with Chronic Pyelonephritis and Cholecystitis. Correlations between Parameters EEG, HRV and White Blood Cell Count

We aim to analyze in bounds KJ Tracey's immunological homunculus conception the relationships between parameters of electroencephalogram (EEG) and heart rate variability (HRV), on the one hand, and the parameters of bhite blood cell count, on the other hand.

METHODS

In basal conditions in 23 men, patients with chronic pyelonephritis and cholecystitis in remission, recorded EEG ("NeuroCom Standard", KhAI Medica, Ukraine) and HRV ("Cardiolab+VSR", KhAI Medica, Ukraine). In portion of blood counted up white blood cell count.

RESULTS

Revealed that canonical correlation between constellation EEG and HRV parameters form with blood level of leukocytes 0.92 (p<10-5), with relative content in white blood cell count stubnuclear neutrophiles 0.93 (p<10-5), segmentonucleary neutrophiles 0.89 (p<10-3), eosinophiles 0.87 (p=0.003), lymphocytes 0.77 (p<10-3) and with monocytes 0.75 (p=0.003).

CONCLUSION

Parameters of white blood cell count significantly modulated by electrical activity some structures of central and autonomic nervous systems.

Tolerogenic dendritic cells

Deficits in immunological tolerance against self-antigens and antigens provided by the diet and commensal microbiota can result in the development of inflammatory and autoimmune disorders. Dendritic cells (DCs) are pivotal regulators of the immune response, specialized in antigen presentation to drive T cell priming and differentiation. DCs also have a tolerogenic function, participating in the enforcement of central and peripheral tolerance and the resolution of ongoing immune responses. Thus, DCs control effector and regulatory mechanisms relevant to the pathology of autoimmune disorders. In this review, we discuss recent findings regarding the control of the adaptive immune response by tolerogenic DCs. A thorough understanding of the mechanisms that control the tolerogenic DC phenotype will guide the development of novel strategies for the treatment of autoimmunity.

Neuroimmune interactions: dendritic cell modulation by the sympathetic nervous system

Dendritic cells are of paramount importance bridging innate and adaptive immune responses. Depending on the context, after sensing environmental antigens, commensal microorganisms, pathogenic agents, or antigens from the diet, dendritic cells may drive either different effector adaptive immune responses or tolerance, avoiding tissue damage. Although the plasticity of the immune response and the capacity to regulate itself are considered essential to orchestrate appropriate physiological responses, it is known that the nervous system plays a relevant role controlling immune cell function. Dendritic cells present in the skin, the intestine, and lymphoid organs, besides expressing adrenergic receptors, can be reached by neurotransmitters released by sympathetic fibers innervating these tissues. These review focus on how neurotransmitters from the sympathetic nervous system can modulate dendritic cell function and how this may impact the immune response and immune-mediated disorders.

Antigen Presentation After Stroke

Stroke induces a local inflammatory reaction and a plethora of innate immune responses in the brain where antigen-presenting cells become prominent. However, to date, it is still unclear whether antigen presentation is relevant to the neuropathological and functional outcome of stroke. Stroke does not trigger overt autoimmune reactions, but neural antigens have been found in lymphoid tissues of patient with stroke and it is unknown whether they promote tolerance or immune reactions that under certain conditions might contribute to the functional worsening observed in some patients. Autoantibodies to neural molecules have also been reported in patients with stroke, but the subclass of antibodies is important for their function, and the contribution of such findings to stroke outcome is not yet clear. Notably, stroke induces immunodepression highlighted by a transient lymphopenia, lymphoid organ atrophy, and monocyte deactivation. While these effects might reduce the chances of autoreactivity, they increase the risk of infection in patients with stroke and most frequently in those with severe stroke. Therefore any potential brain protective effect of stroke-induced immunodepression by attenuating or preventing lymphocyte-mediated brain damage is confounded by stroke severity and an increased incidence of infections. Systemic inflammation due to a number of comorbidities that are frequent in patients with stroke is also associated to a poor outcome. Herein, we review some relevant findings regarding the identification of neural antigens in stroke and discuss their potential contribution to the functional outcome of stroke.

β2-adrenoceptor signaling reduction in dendritic cells is involved in the inflammatory response in adjuvant-induced arthritic rats

Rheumatoid arthritis (RA) is characterized by inflammation of the synovium, which leads to the progressive destruction of cartilage and bone. Adrenoreceptor (AR) signaling may play an important role in modulating dendritic cell (DC), which may be involved in the pathogenesis of RA. We examined the effect of the β-AR agonist isoprenaline (ISO) on DC function, the impact of the β₂-AR agonist salbutamol on adjuvant-induced arthritic (AA) rats, and changes in β₂-AR signaling in DCs during the course of AA. ISO inhibited the expression of the surface molecules CD86 and MHC-II, inhibited the stimulation of T lymphocyte proliferation by DC and TNF-α secretion, and promoted DC antigen uptake and IL-10 secretion. The effects of ISO on MHC-II expression, DC stimulation of T lymphocyte proliferation, and DC antigen uptake were mediated by β₂-AR. Treatment with salbutamol ameliorated the severity of AA and histopathology of the joints and inhibited proliferation of thymus lymphocytes and FLS in vivo. β₂-AR signaling was weaker in AA rats compared to the control. Elevated GRK2 and decreased β₂-AR expression in DC cytomembranes were observed in AA and may have decreased the anti-inflammatory effect of β₂-AR signaling. Decreased β₂-AR signaling may be relevant to the exacerbation of arthritis inflammation.

Norepinephrine Controls Effector T Cell Differentiation through β2-Adrenergic Receptor-Mediated Inhibition of NF-κB and AP-1 in Dendritic Cells

Despite accumulating evidence indicating that neurotransmitters released by the sympathetic nervous system can modulate the activity of innate immune cells, we still know very little about how norepinephrine impacts signaling pathways in dendritic cells (DC) and the consequence of that in DC-driven T cell differentiation. In this article, we demonstrate that β2-adrenergic receptor (β2AR) activation in LPS-stimulated DC does not impair their ability to promote T cell proliferation; however, it diminishes IL-12p70 secretion, leading to a shift in the IL-12p70/IL-23 ratio. Although β2AR stimulation in DC induces protein kinase A-dependent cAMP-responsive element-binding protein phosphorylation, the effect of changing the profile of cytokines produced upon LPS challenge occurs in a protein kinase A-independent manner and, rather, is associated with inhibition of the NF-κB and AP-1 signaling pathways. Moreover, as a consequence of the inverted IL-12p70/IL-23 ratio following β2AR stimulation, LPS-stimulated DC promoted the generation of CD4(+) T cells that, upon TCR engagement, produced lower amounts of IFN-γ and higher levels of IL-17. These findings provide new insights into molecular and cellular mechanisms by which β2AR stimulation in murine DC can influence the generation of adaptive immune responses and may explain some aspects of how sympathetic nervous system activity can modulate immune function.

The Neuromodulation of the Intestinal Immune System and Its Relevance in Inflammatory Bowel Disease

One of the main tasks of the immune system is to discriminate and appropriately react to “danger” or “non-danger” signals. This is crucial in the gastrointestinal tract, where the immune system is confronted with a myriad of food antigens and symbiotic microflora that are in constant contact with the mucosa, in addition to any potential pathogens. This large number of antigens and commensal microflora, which are essential for providing vital nutrients, must be tolerated by the intestinal immune system to prevent aberrant inflammation. Hence, the balance between immune activation versus tolerance should be tightly regulated to maintain intestinal homeostasis and to prevent immune activation indiscriminately against all luminal antigens. Loss of this delicate equilibrium can lead to chronic activation of the intestinal immune response resulting in intestinal disorders, such as inflammatory bowel diseases (IBD). In order to maintain homeostasis, the immune system has evolved diverse regulatory strategies including additional non-immunological actors able to control the immune response. Accumulating evidence strongly indicates a bidirectional link between the two systems in which the brain modulates the immune response via the detection of circulating cytokines and via direct afferent input from sensory fibers and from enteric neurons. In the current review, we will highlight the most recent findings regarding the cross-talk between the nervous system and the mucosal immune system and will discuss the potential use of these neuronal circuits and neuromediators as novel therapeutic tools to reestablish immune tolerance and treat intestinal chronic inflammation.

Neural regulation of hematopoiesis, inflammation, and cancer

Although the function of the autonomic nervous system (ANS) in mediating the flight-or-fight response was recognized decades ago, the crucial role of peripheral innervation in regulating cell behavior and response to the microenvironment has only recently emerged. In the hematopoietic system, the ANS regulates stem cell niche homeostasis and regeneration and fine-tunes the inflammatory response. Additionally, emerging data suggest that cancer cells take advantage of innervating neural circuitry to promote their progression. These new discoveries outline the need to redesign therapeutic strategies to target this underappreciated stromal constituent. Here, we review the importance of neural signaling in hematopoietic homeostasis, inflammation, and cancer.

Regulation of differentiation and function of helper T cells by lymphocyte-derived catecholamines via α₁- and β₂-adrenoceptors

OBJECTIVE

Recently, we have reported that lymphocyte-derived endogenous catecholamines (CAs) facilitate a shift in the T helper (Th)1/Th2 balance towards Th2. The purpose of this study was to explore the involvement of adrenoreceptors (ARs) in Th differentiation and function modulation by lymphocyte-derived CAs.

METHODS

Lymphocytes were separated from the mesenteric lymph nodes of mice, stimulated with concanavalin A (Con A) and treated with pargyline, an inhibitor of CA degradation.

RESULTS

Pargyline downregulated the expression of Th1-relative factors, T-bet, interferon (IFN)-γ and interleukin (IL)-2, but upregulated the expression of Th2-relative factors, GATA-3, IL-4 and IL-10. Pargyline reduced the percentage of IFN-γ-producing CD4+ cells and the CD4+IFN-γ+/CD4+IL-4+ cell ratio, although it did not alter the proportion of IL-4-producing CD4+ cells. In addition, the percentage of CD4+CD26+ T cells and the CD4+CD26+/CD4+CD30+ cell ratio were also reduced in the pargyline-treated group. Furthermore, Con A-activated T cells treated with pargyline produced a lower level of IFN-γ and a higher level of IL-4 than the control group. All these effects were blocked by the α1-AR antagonist corynanthine or the β2-AR antagonist ICI 118551, but not by the α2-AR antagonist yohimbine or β1-AR antagonist atenolol.

CONCLUSIONS

These results imply that lymphocyte-derived CAs promote polarization of differentiation and function towards Th2 cells and that this effect is mediated by α1-AR and β2-AR.

β-Adrenergic blockade protects BALB/c mice against infection with a small inoculum of Leishmania mexicana mexicana (LV4)

In order to test the influence of the sympathetic nervous system on Leishmania mexicana infection, groups of female BALB/c mice were treated (i.p.) with the non-selective β-adrenergic receptor (β-AR) antagonist (S)-propranolol (5mg/kg thrice a day), the β2-AR agonist clenbuterol (1mg/kg once a day) or the α2-AR antagonist yohimbine (2mg/kg twice a day) during 5days. During the second day of treatments, mice were inoculated in the footpad with 1×10(6) or 1×10(3) metacyclic promastigotes of L. mexicana mexicana (LV4). The lesion size was measured weekly, and parasite burden on week 12. In mice treated with (S)-propranolol, the percentage of splenic T lymphocytes producing IFN-γ after antigen challenge was determined by flow cytometry. In mice infected with 1×10(6) parasites, only (S)-propranolol caused a reduction of footpad swelling (p<0.05, weeks 11-12), without effects on parasite burden, or in the percentage of IFN-γ-immunopositive CD4(+) or CD8(+) T lymphocytes. In mice infected with 1×10(3) parasites, the effects of treatments vs. control group were as follows: (a) inhibition of footpad swelling by (S)-propranolol (p<0.01, weeks 3-12), clenbuterol (p<0.05, weeks 7-10), and yohimbine (p<0.01, week 7); (b) a decrease of the parasite burden by (S)-propranolol (p<0.01) and yohimbine (p<0.05); (c) in control mice the percentage of CD4(+) T-cells producing IFN-γ was 6.2±0.5%, while in those treated with (S)-propranolol it increased to 8.7±0.6% (p<0.01); (d) in control mice the percentage of CD8(+) T-cells producing IFN-γ was 3.1±0.4%, while in those treated with (S)-propranolol it increased to 10.4±0.2% (p<0.01). These results indicate that the blockade of β-ARs during infection of BALB/c mice with an inoculum of L. mexicana mexicana similar to that delivered by the bite of a sand fly produces a Th1 bias in the immune response, favoring an increment of T lymphocytes secreting IFN-γ, which correlated with a reduced parasite burden (p<0.05, Spearman's test). We suggest that β-AR antagonists could be of therapeutic value, either as treatment or as adjuvant of vaccines for L. mexicana.

Neuroendocrine regulation of inflammation

The interaction between the sympathetic nervous system and the immune system has been documented over the last several decades. In this review, the neuroanatomical, cellular, and molecular evidence for neuroimmune regulation in the maintenance of immune homeostasis will be discussed, as well as the potential impact of neuroimmune dysregulation in health and disease.

Antigen-specific immune reactions to ischemic stroke

Brain proteins are detected in the cerebrospinal fluid (CSF) and blood of stroke patients and their concentration is related to the extent of brain damage. Antibodies against brain antigens develop after stroke, suggesting a humoral immune response to the brain injury. Furthermore, induced immune tolerance is beneficial in animal models of cerebral ischemia. The presence of circulating T cells sensitized against brain antigens, and antigen presenting cells (APCs) carrying brain antigens in draining lymphoid tissue of stroke patients support the notion that stroke might induce antigen-specific immune responses. After stroke, brain proteins that are normally hidden from the periphery, inflammatory mediators, and danger signals can exit the brain through several efflux routes. They can reach the blood after leaking out of the damaged blood-brain barrier (BBB) or following the drainage of interstitial fluid to the dural venous sinus, or reach the cervical lymph nodes through the nasal lymphatics following CSF drainage along the arachnoid sheaths of nerves across the nasal submucosa. The route and mode of access of brain antigens to lymphoid tissue could influence the type of response. Central and peripheral tolerance prevents autoimmunity, but the actual mechanisms of tolerance to brain antigens released into the periphery in the presence of inflammation, danger signals, and APCs, are not fully characterized. Stroke does not systematically trigger autoimmunity, but under certain circumstances, such as pronounced systemic inflammation or infection, autoreactive T cells could escape the tolerance controls. Further investigation is needed to elucidate whether antigen-specific immune events could underlie neurological complications impairing recovery from stroke.

Divergent neuroendocrine responses to localized and systemic inflammation

The sympathetic nervous system (SNS) is part of an integrative network that functions to restore homeostasis following injury and infection. The SNS can provide negative feedback control over inflammation through the secretion of catecholamines from postganglionic sympathetic neurons and adrenal chromaffin cells (ACCs). Central autonomic structures receive information regarding the inflammatory status of the body and reflexively modulate SNS activity. However, inflammation and infection can also directly regulate SNS function by peripheral actions on postganglionic cells. The present review discusses how inflammation activates autonomic reflex pathways and compares the effect of localized and systemic inflammation on ACCs and postganglionic sympathetic neurons. Systemic inflammation significantly enhanced catecholamine secretion through an increase in Ca(2+) release from the endoplasmic reticulum. In contrast, acute and chronic GI inflammation reduced voltage-gated Ca(2+) current. Thus it appears that the mechanisms underlying the effects of peripheral and systemic inflammation neuroendocrine function converge on the modulation of intracellular Ca(2+) signaling.

The influence of pemirolast on autonomic imbalance in rat cystitis model

Cyclophosphamide (CP) treatment is associated with the risk of haemorrhagic cystitis (HC). Moreover, CP-induced HC is complicated by autonomic nervous system (ANS) dysfunction. Pemirolast is thought to be a mast cell stabiliser that inhibits the release of many inflammatory mediators and sensory neuropeptides, and thus, it may be considered a potential chemoprotective HC agent. The aim of the study was to indirectly estimate the effect of pemirolast in experimental HC by measuring ANS activity with the heart rate variability (HRV) method. In CP-treated rats, we found a decreasing trend of overall autonomic activity, together with an imbalance between the main components, and a dominant very low frequency (VLF) power component. Pemirolast treatment did not improve the total HRV power value or the main non-normalized HRV components. Moreover, CP-HC animals treated with pemirolast displayed a different disproportion of normalized spectral components as compared to both control and CP-HC animals without pemirolast treatment, with the balance between normalized low frequency (nLF) and normalized high frequency (nHF) shifted towards nLF. This finding, together with a relatively high VLF tension, indicates that the pemirolast treatment resulted in high sympathetic activity that may contribute to HC exacerbation; thus, this agent seems to be ineffective in CP-induced HC.

Nerve-derived transmitters including peptides influence cutaneous immunology

Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis, rosacea and acne; are widely believed to be exacerbated by stress. A growing body of research now suggests that neuropeptides and neurotransmitters serve as a link between these two systems. Neuropeptides and neurotransmitters are released by nerves innervating the skin to influence important actors of the immune system, such as Langerhans cells and mast cells, which are located within close anatomic proximity. Catecholamines and other sympathetic transmitters that are released in response to activation of the sympathetic nervous system are also able to reach the skin and affect immune cells. Neuropeptides appear to direct the outcome of Langerhans cell antigen presentation with regard to the subtypes of Th cells generated and neuropeptides induce the degranulation of mast cells, among other effects. Additionally, endothelial cells, which release many inflammatory mediators and express cell surface molecules that allow leukocytes to exit the bloodstream, appear to be regulated by certain neuropeptides and transmitters. This review focuses on the evidence that products of nerves have important regulatory activities on antigen presentation, mast cell function and endothelial cell biology. These activities are highly likely to have clinical and therapeutic relevance.

Modulation of haemocyte phagocytic and antibacterial activity by alpha-adrenergic receptor in scallop Chlamys farreri

The adrenergic receptors are a class of G protein-coupled receptors, through which norepinephrine and epinephrine trigger the second messenger to modulate the immune response in immunocytes of vertebrate. In the present study, a gene coding the homologue of α-adrenergic receptor was identified from scallop Chlamys farreri (designated CfαAR). Its deduced protein comprised 318 amino acids, and contained a conserved 7tm_1 domain. After CfαAR protein was expressed in the HEK293 cells, the stimulation of octopamine, tyramine, epinephrine and isoprenaline (β-adrenergic receptor agonist) did not change significantly the intracellular cAMP concentration, whereas the stimulation of norepinephrine and phenylephrine (α-adrenergic receptor agonist) lowered significantly the cAMP level to 0.52 and 0.84 pmol μl(-1) (P < 0.05), respectively. The CfαAR transcripts were ubiquitously detected in the tested tissues including haemocytes, adductor muscle, kidney, hepatopancreas, gill, gonad and mantle, with the highest expression in the gill. The expression level of CfαAR mRNA decreased significantly (0.21-fold, P < 0.05) at 3 h after the challenge of bacteria Vibrio anguillarum. Then, it began to increase (4.74-fold, P < 0.05) at 12 h, and reached the highest level (4.92-fold, P < 0.05) at 24 h after bacteria challenge. The addition of α-adrenergic receptor agonist to the primary scallop haemocytes repressed significantly the increase of phagocytic and antibacterial activity induced by LPS stimulation, while the induction was reverted by the addition of α-adrenergic receptor antagonist. These results collectively suggested that α-adrenergic receptor could be regulated dynamically in the transcriptional level during the immune response, and it could modulate the haemocyte phagocytic and antibacterial function through the second messenger cAMP, which might be requisite for pathogen elimination and the homeostasis maintenance in scallop.

Suppression of phagosome proteolysis and Matrigel migration with the α2-adrenergic receptor agonist dexmedetomidine in murine dendritic cells

Dexmedetomidine is a highly-selective α2-adrenergic receptor agonist used for sedation of critically ill patients in an intensive care setting. Dendritic cells (DCs) in peripheral tissues sense certain foreign antigens and ingest and process them, while migrating to the regional lymph node. Then, DCs present the processed antigen on their surface to stimulate the clonal proliferation of cognitive lymphocytes, leading to the establishment of adaptive immunity. In murine bone marrow-derived DCs, dexmedetomidine significantly delayed the intracellular proteolytic degradation of ovalbumin, while it did not affect phagocytosis, decreased the expression of the surface molecules I-A(b) and CD86, and suppressed cognitive helper T-cell proliferation. Furthermore, dexmedetomidine significantly suppressed DC migration both in vitro, using a Matrigel migration assay, and in vivo, using a foot pad-popliteal lymph node migration assay, which may be ascribed to the inhibition of type IV collagenase/gelatinase activity. Finally, vaccination with dexmedetomidine-treated DCs significantly suppressed the contact hypersensitivity reaction in vivo. These results indicate that dexmedetomidine may suppress immunity by inhibiting DC antigen processing/presentation and migration.

Neural networks in intestinal immunoregulation

Key physiological functions of the intestine are governed by nerves and neurotransmitters. This complex control relies on two neuronal systems: an extrinsic innervation supplied by the two branches of the autonomic nervous system and an intrinsic innervation provided by the enteric nervous system. As a result of constant exposure to commensal and pathogenic microflora, the intestine developed a tightly regulated immune system. In this review, we cover the current knowledge on the interactions between the gut innervation and the intestinal immune system. The relations between extrinsic and intrinsic neuronal inputs are highlighted with regards to the intestinal immune response. Moreover, we discuss the latest findings on mechanisms underlying inflammatory neural reflexes and examine their relevance in the context of the intestinal inflammation. Finally, we discuss some of the recent data on the identification of the gut microbiota as an emerging player influencing the brain function.

β2-Adrenoreceptor agonist inhibits antigen cross-presentation by dendritic cells

Despite widespread usage of β-adrenergic receptor (AR) agonists and antagonists in current clinical practice, our understanding of their interactions with the immune system is surprisingly sparse. Among the AR expressed by dendritic cells (DC), β2-AR can modify in vitro cytokine release upon stimulation. Because DC play a pivotal role in CD8(+) T cell immune responses, we examined the effects of β2-AR stimulation on MHC class I exogenous peptide presentation and cross-presentation capacities. We demonstrate that β2-AR agonist-exposed mature DC display a reduced ability to cross-present protein Ags while retaining their exogenous peptide presentation capability. This effect is mediated through the nonclassical inhibitory G (Gαi/0) protein. Moreover, inhibition of cross-presentation is neither due to reduced costimulatory molecule expression nor Ag uptake, but rather to impaired phagosomal Ag degradation. We observed a crosstalk between the TLR4 and β2-AR transduction pathways at the NF-κB level. In vivo, β2-AR agonist treatment of mice inhibits Ag protein cross-presentation to CD8(+) T cells but preserves their exogenous MHC class I peptide presentation capability. These findings may explain some side effects on the immune system associated with stress or β-agonist treatment and pave the way for the development of new immunomodulatory strategies.

Role of peripheral nerve fibres in acute and chronic inflammation in arthritis

The peripheral nervous system takes an active part in inflammatory processes by regulating effector cell function and reallocation of energy to the immune system. During acute inflammation, rapid neuronal reorganization and change of activity takes place. The hallmarks of this process are an increase in systemic sympathetic activity, a decrease in systemic parasympathetic activity and loss of sympathetic nerve fibres from sites of inflammation concomitant with increased innervation with sensory nerve fibres and increased sensory nerve fibre activity. On a systemic level, the increase in sympathetic activity (and decrease in parasympathetic activity) is necessary to provide enough energy to nourish the activated immune system. In locally inflamed tissue, the decrease in sympathetic nerve fibre density results in reduced anti-inflammatory signalling and, together with neuropeptides released from sensory nerve fibres, promotes local inflammation. In acute inflammation, this 'inflammatory configuration' of the peripheral nervous system favours the rapid clearance of antigenic threats. However, in chronic autoimmune inflammation, these changes of the peripheral nervous system lead to an unfavourable situation with ongoing energy reallocation and continuous local destruction. As an example of a chronic inflammatory condition, we discuss evidence for neuroimmune regulation in autoimmune arthritis with a focus on the sympathetic nervous system.

Enhanced phosphorylation of MAPKs by NE promotes TNF-α production by macrophage through α adrenergic receptor

The aim of this study was to investigate whether norepinephrine (NE) could regulate macrophage production of tumor necrosis factor alpha (TNF-α) by influencing the phosphorylation of mitogen-activated protein kinases (MAPKs). Primary macrophages from male BALB/c mice were applied to explore the mechanism by which NE influences the the secretion of TNF-α when macrophages were activated by lipopolysaccharides (LPS). We found that NE could increase crophage production of TNF-α when macrophages were activated by LPS, and this effect could be inhibited by α adrenergic antagonist phentolamine. Also, NE could increase the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinases (ERK), and p38, through α receptor. Furthermore, JNK inhibitor SP600125, ERK inhibitor U0126, and p38 inhibitor SB203580 could all partially counteract NE's effect on the phosphorylation of MAPKs, as well as TNF-α production by macrophages. This study revealed that as macrophages were activated by LPS, NE promoted the secretion of inflammatory factors by increasing the phosphorylation of MAPKs through an α receptor-dependent pathway. Our results provide the evidence of a relationship between stress and diseases, as well as the mechanism by which stress induces or affects the inflammation-related diseases.

G protein-coupled receptors as therapeutic targets for multiple sclerosis

G protein-coupled receptors (GPCRs) mediate most of our physiological responses to hormones, neurotransmitters and environmental stimulants. They are considered as the most successful therapeutic targets for a broad spectrum of diseases. Multiple sclerosis (MS) is an inflammatory disease that is characterized by immune-mediated demyelination and degeneration of the central nervous system (CNS). It is the leading cause of non-traumatic disability in young adults. Great progress has been made over the past few decades in understanding the pathogenesis of MS. Numerous data from animal and clinical studies indicate that many GPCRs are critically involved in various aspects of MS pathogenesis, including antigen presentation, cytokine production, T-cell differentiation, T-cell proliferation, T-cell invasion, etc. In this review, we summarize the recent findings regarding the expression or functional changes of GPCRs in MS patients or animal models, and the influences of GPCRs on disease severity upon genetic or pharmacological manipulations. Hopefully some of these findings will lead to the development of novel therapies for MS in the near future.

Adrenoceptor-mediated enhancement of interleukin-33 production by dendritic cells

While noradrenaline and adrenaline suppress some aspects of immune functions, the immune enhancement via these catecholamines is not well understood. Interleukin (IL)-33, a novel member of the IL-1 family, promotes T helper type 2 (T(h)2)-associated inflammations and plays a role in allergic diseases. However, the precise immune cell source and the stimulating factors for IL-33 production are less well characterized. In the present study, we examined the effects of noradrenaline and adrenaline, stress-related catecholamines, on IL-33 production by dendritic cells (DCs). Murine bone marrow-derived DCs were stimulated with lipopolysaccharide (LPS) in the presence or absence of these catecholamines. LPS alone slightly increased IL-33 production by DCs. Noradrenaline or adrenaline dramatically enhanced IL-33 mRNA expression and its protein synthesis by DCs upon LPS stimulation. The noradrenaline-induced enhancement of IL-33 production was completely blocked by β(2)-adrenoceptor specific antagonist ICI 118,551, while β(2)-adrenoceptor specific agonist salmeterol enhanced DC production of IL-33. Protein kinase A (PKA) specific inhibitor H89 blocked the noradrenaline-induced IL-33 production. Cyclic adenosine monophosphate (cAMP) and its analogue enhanced DC production of IL-33 upon LPS stimulation. Thus, β(2)-adrenoceptor-mediated cAMP-PKA pathway appears to enhance DC production of IL-33. The adrenoceptor-mediated enhancement of IL-33 production by DCs might be associated with the stress-related progression of T(h)2-associated disorders.