The intriguing mission of neuropeptide Y in the immune system

Endogenous Antimicrobial-Immunomodulatory Molecules: Networking Biomolecules of Innate Immunity

Endogenous antimicrobial-immunomodulatory molecules (EAIMs) are essential to immune-mediated human health and evolution. Conventionally, antimicrobial peptides (AMPs) have been regarded as the dominant endogenous antimicrobial molecule; however, AMPs are not sufficient to account for the full spectrum of antimicrobial-immunomodulatory duality occurring within the human body. The threat posed by pathogenic microbes is pervasive with the capacity for widespread impact across many organ systems and multiple biochemical pathways; accordingly, the host needs the capacity to react with an equally diverse response. This can be attained by having EAIMs that traverse the full range of molecular size (small to large molecules) and structural diversity (including molecules other than peptides). This review identifies multiple molecules (peptide/protein, lipid, carbohydrate, nucleic acid, small organic molecule, and metallic cation) as EAIMs and discusses the possibility of cooperative, additive effects amongst the various EAIM classes during the host response to a microbial assault. This comprehensive consideration of the full molecular diversity of EAIMs enables the conclusion that EAIMs constitute a previously uncatalogued structurally diverse and collectively underappreciated immuno-active group of integrated molecular responders within the innate immune system's first line of defence.

Effects of neuropeptide Y on the immune-protection and intestinal tract of juvenile Micropterus salmoides

Neuropeptide Y is known to be directly or indirectly involved in immune regulation. The immune effects of NPY include immune cell transport, helper T cell differentiation, cytokine secretion, staining and killer cell activity, phagocytosis and production of reactive oxygen species. In this study, we investigated the immunoprotective effect of synthetic NPY on largemouth bass larvae. For the first time, the dose and time effects of NPY injection on largemouth bass was explored, and then Poly I:C and LPS infection was carried out in juvenile largemouth bass, respectively, after the injection of NPY. The results showed that NPY could reduce the inflammatory response by inhibiting the expression of il-1β, tgf-β, ifn-γ and other immune factors in head kidney, spleen and brain, and alleviate the immune stress caused by strong inflammatory response in the early stage of infection. Meanwhile, NPY injection ameliorated the intestinal tissue damage caused by infection. This study provides a new way to protect juvenile fish and improve its innate immunity.

Navigating the blurred path of mixed neuroimmune signaling

Evolution has created complex mechanisms to sense environmental danger and protect tissues, with the nervous and immune systems playing pivotal roles. These systems work together, coordinating local and systemic reflexes to restore homeostasis in response to tissue injury and infection. By sharing receptors and ligands, they influence the pathogenesis of various diseases. Recently, a less-explored aspect of neuroimmune communication has emerged: the release of neuropeptides from immune cells and cytokines/chemokines from sensory neurons. This article reviews evidence of this unique neuroimmune interplay and its impact on the development of allergy, inflammation, itch, and pain. We highlight the effects of this neuroimmune signaling on vital processes such as host defense, tissue repair, and inflammation resolution, providing avenues for exploration of the underlying mechanisms and therapeutic potential of this signaling.

Immuno-protective effect of neuropeptide Y immersion on the juvenile tilapia infected by Streptococcus agalactiae

Neuropeptide Y (NPY), an important neurotransmitter, is widely distributed in the nervous systems of vertebrates. Multiple functions of NPY in mammals include the regulation of brain activity, emotion, stress response, feeding, digestion, metabolism and immune function. In the present study, we used synthetic NPY to immerse juvenile tilapia, thus firstly exploring the dose and time effect of this immersion. The results showed that the expression level of y8b and serum glucose increased after NPY immersion. When juvenile tilapia was challenged with Streptococcus agalactiae (S. agalactiae), no matter before or after the administration of NPY-immersion, it was found that NPY immersion could inhibit the expression of il-1β induced by S. agalactiae in telencephalon, hypothalamus, spleen and head kidney, and then promote the expression of il-10. In addition, NPY-immersion could reduce the activity of serum SOD but increase that of lysozyme, and ameliorate tissue damage in the head kidney and spleen of juvenile tilapia caused by S. agalactiae infection. This study firstly proposes the potential of NPY to be an immune protect factor in juvenile fish, and the results can provide a reference for the application of immersion administration in the immune protection of juvenile fish.

Neuropeptide Y Antagonizes Development of Pulmonary Fibrosis through IL-1β Inhibition

Neuropeptide Y (NPY), a 36 amino acid residue polypeptide distributed throughout the nervous system, acts on various immune cells in many organs, including the respiratory system. However, little is known about its role in the pathogenesis of pulmonary fibrosis. This study was performed to determine the effects of NPY on pulmonary fibrosis. NPY-deficient and wild-type mice were intratracheally administered bleomycin. Inflammatory cells, cytokine concentrations, and morphological morphometry of the lungs were analyzed. Serum NPY concentrations were also measured in patients with idiopathic pulmonary fibrosis and healthy control subjects. NPY-deficient mice exhibited significantly enhanced pulmonary fibrosis and higher IL-1β concentrations in the lungs compared with wild-type mice. Exogenous NPY treatment suppressed the development of bleomycin-induced lung fibrosis and decreased IL-1β concentrations in the lungs. Moreover, IL-1β neutralization in NPY-deficient mice attenuated the fibrotic changes. NPY decreased IL-1β release, and Y1 receptor antagonists inhibited IL-1β release and induced epithelial-mesenchymal transition in human alveolar epithelial cells. Patients with idiopathic pulmonary fibrosis had lower NPY and greater IL-1β concentrations in the serums compared with healthy control subjects. NPY expression was mainly observed around bronchial epithelial cells in human idiopathic pulmonary fibrosis lungs. These data suggest that NPY plays a protective role against pulmonary fibrosis by suppressing IL-1β release, and manipulating the NPY-Y1 receptor axis could be a potential therapeutic strategy for delaying disease progression.

Neuropeptide Y Promotes Human M2 Macrophage Polarization and Enhances p62/SQSTM1-Dependent Autophagy and NRF2 Activation

Neuropeptide Y (NPY) is an abundantly expressed peptide capable of modulating innate and adaptive immune responses and regulating chemotaxis and cytokine secretion by macrophages. Abnormal regulation of NPY is involved in the development of atherosclerosis. The inflammatory infiltrate within atherosclerotic plaque is characterized by accumulation of macrophages, which are subject to reprogram their phenotypes in response to environmental signals. Macrophage number and phenotype influence plaque fate. Here, we investigated the effect of NPY on the changes in phenotype and functions of human macrophages, from the pro-inflammatory phenotype M1 to the reparative M2, indicative of atherosclerosis regression or stabilization. Human monocytes were differentiated in vitro into macrophages with M-CSF (M0) and polarized towards an M1 phenotype with IFN-γ plus LPS M(IFN-γ/LPS) or M2 with IL-10 (M IL-10) and further challenged with NPY (10-7-10-9 M) for 8-36 h. Cell phenotype and functions were analyzed by immunofluorescence and immunochemical analyses. NPY affected macrophage surface markers and secretome profile expression, thus shifting macrophages toward an M2-like phenotype. NPY also prevented the impairment of endocytosis triggered by the oxysterol 7-keto-cholesterol (7KC) and prevented 7KC-induced foam cell formation by reducing the lipid droplet accumulation in M0 macrophages. NPY-treated M0 macrophages enhanced the autophagosome formation by upregulating the cell content of the autophagy markers LC3-II and p62-SQSTM1, increased activation of the anti-oxidative transcription factor NRF2 (NF-E2-related factor 2), and subsequently induced its target gene HMOX1 that encodes heme oxygenase-1. Our findings indicate that NPY has a cytoprotective effect with respect to the progression of the inflammatory pathway, both enhancing p62/SQSTM1-dependent autophagy and the NRF2-antioxidant signaling pathway in macrophages. NPY signaling may have a crucial role in tissue homeostasis in host inflammatory responses through the regulation of macrophage balance and functions within atherosclerosis.

Neuropeptides in Cancer: Friend and Foe?

Neuropeptides are small regulatory molecules found throughout the body, most notably in the nervous, cardiovascular, and gastrointestinal systems. They serve as neurotransmitters or hormones in the regulation of diverse physiological processes. Cancer cells escape normal growth control mechanisms by altering their expression of growth factors, receptors, or intracellular signals, and neuropeptides have recently been recognized as mitogens in cancer growth and development. Many neuropeptides and their receptors exist in multiple subtypes, coupling with different downstream signaling pathways and playing distinct roles in cancer progression. The consideration of neuropeptide/receptor systems as anticancer targets is already leading to new biological and diagnostic knowledge that has the potential to enhance the understanding and treatment of cancer. In this review, recent discoveries regarding neuropeptides in a wide range of cancers, emphasizing their mechanisms of action, signaling cascades, regulation, and therapeutic potential, are discussed. Current technologies used to manipulate and analyze neuropeptides/receptors are described. Applications of neuropeptide analogs and their receptor inhibitors in translational studies and radio-oncology are rapidly increasing, and the possibility for their integration into therapeutic trials and clinical treatment appears promising.

Neuroendocrine regulations in tissue-specific immunity: From mechanism to applications in tumor

Immune responses in nonlymphoid tissues play a vital role in the maintenance of homeostasis. Lots of evidence supports that tissue-specific immune cells provide defense against tumor through the localization in different tissue throughout the body, and can be regulated by diverse factors. Accordingly, the distribution of nervous tissue is also tissue-specific which is essential in the growth of corresponding organs, and the occurrence and development of tumor. Although there have been many mature perspectives on the neuroendocrine regulation in tumor microenvironment, the neuroendocrine regulation of tissue-specific immune cells has not yet been summarized. In this review, we focus on how tissue immune responses are influenced by autonomic nervous system, sensory nerves, and various neuroendocrine factors and reversely how tissue-specific immune cells communicate with neuroendocrine system through releasing different factors. Furthermore, we pay attention to the potential mechanisms of neuroendocrine-tissue specific immunity axis involved in tumors. This may provide new insights for the immunotherapy of tumors in the future.

Tear film and ocular surface neuropeptides: Characteristics, synthesis, signaling and implications for ocular surface and systemic diseases

Ocular surface neuropeptides are vital molecules primarily involved in maintaining ocular surface integrity and homeostasis. They also serve as communication channels between the nervous system and the immune system, maintaining the homeostasis of the ocular surface. Tear film and ocular surface neuropeptides have a role in disease often due to abnormalities in their synthesis (either high or low production), signaling through defective receptors, or both. This creates imbalances in otherwise normal physiological processes. They have been observed to be altered in many ocular surface and systemic diseases including dry eye disease, ocular allergy, keratoconus, LASIK-induced dry eye, pterygium, neurotrophic keratitis, corneal graft rejection, microbial keratitis, headaches and diabetes. This review examines the characteristics of neuropeptides, their synthesis and their signaling through G-protein coupled receptors. The review also explores the types of neuropeptides within the tears and ocular surface, and how they change in ocular and systemic diseases.

Neuron-derived neuropeptide Y fine-tunes the splenic immune responses

The nervous and immune systems are closely entwined to maintain the immune balance in health and disease. Here, we showed that LPS can activate suprarenal and celiac ganglia (SrG-CG) neurons and upregulate NPY expression in rats. Single-cell sequencing analysis revealed that knockdown of the NPY gene in SrG-CG altered the proliferation and activation of splenic lymphocytes. In a neuron and splenocyte coculture system and in vivo experiments, neuronal NPY in SrG-CG attenuated the splenic immune response. Notably, we demonstrated that neuronal NPF in Drosophila exerted a conservative immunomodulatory effect. Moreover, numerous SNPs in NPY and its receptors were significantly associated with human autoimmune diseases, which was further supported by the autoimmune disease patients and mouse model experiments. Together, we demonstrated that NPY is an ancient language for nervous-immune system crosstalk and might be utilized to alleviate inflammatory storms during infection and to modulate immune balance in autoimmune diseases.

Neuropeptide Y attenuates cardiac remodeling and deterioration of function following myocardial infarction

Plasma levels of neuropeptide Y (NPY) are elevated in patients with acute myocardial infarction (AMI), but its role in AMI remains unclear, which was examined here in NPY wild-type/knockout (WT/KO) mice treated with/without exogenous NPY and its Y1 receptor antagonist (Y1Ra) BIBP 3226. We found that AMI mice lacking NPY developed more severe AMI than WT mice with worse cardiac dysfunction, progressive cardiac inflammation and fibrosis, and excessive apoptosis but impairing angiogenesis. All of these changes were reversed when the NPY KO mice were treated with exogenous NPY in a dose-dependent manner. Interestingly, treatment with NPY also dose dependently attenuated AMI in WT mice, which was blocked by BIBP 3226. Phenotypically, cardiac NPY was de novo expressed by infiltrating macrophages during the repairing or fibrosing process in heart-failure patients and AMI mice. Mechanistically, NPY was induced by transforming growth factor (TGF)-β1 in bone marrow-derived macrophages and signaled through its Y1R to exert its pathophysiological activities by inhibiting p38/nuclear factor κB (NF-κB)-mediated M1 macrophage activation while promoting the reparative M2 phenotype in vivo and in vitro. In conclusion, NPY can attenuate AMI in mice. Inhibition of cardiac inflammation and fibrosis while enhancing angiogenesis but reducing apoptosis may be the underlying mechanisms through which NPY attenuates cardiac remodeling and deterioration of function following AMI.

Patho-immunological mechanisms of vitiligo: the role of the innate and adaptive immunities and environmental stress factors

Epidermal melanocyte loss in vitiligo, triggered by stresses ranging from trauma to emotional stress, chemical exposure or metabolite imbalance, to the unknown, can stimulate oxidative stress in pigment cells, which secrete damage-associated molecular patterns that then initiate innate immune responses. Antigen presentation to melanocytes leads to stimulation of autoreactive T-cell responses, with further targeting of pigment cells. Studies show a pathogenic basis for cellular stress, innate immune responses and adaptive immunity in vitiligo. Improved understanding of the aetiological mechanisms in vitiligo has already resulted in successful use of the Jak inhibitors in vitiligo. In this review, we outline the current understanding of the pathological mechanisms in vitiligo and locate loci to which therapeutic attack might be directed.

Current Insights Into the Role of Neuropeptide Y in Skin Physiology and Pathology

Neuropeptide Y is widely distributed within the body and has long been implicated as a contributor to skin disease based on the correlative clinical data. However, until recently, there have been few empirical investigations to determine whether NPY has a pathophysiological role in the skin. Due to appearance-altering phenotypes of atopic dermatitis, psoriasis, and vitiligo, those suffering from these diseases often face multiple forms of negative social attention. This often results in psychological stress, which has been shown to exacerbate inflammatory skin diseases - creating a vicious cycle that perpetuates disease. This has been shown to drive severe depression, which has resulted in suicidal ideation being a comorbidity of these diseases. Herein, we review what is currently known about the associations of NPY with skin diseases and stress. We also review and provide educated guessing what the effects NPY can have in the skin. Inflammatory skin diseases can affect physical appearance to have significant, negative impacts on quality of life. No cure exists for these conditions, highlighting the need for identification of novel proteins/neuropetides, like NPY, that can be targeted therapeutically. This review sets the stage for future investigations into the role of NPY in skin biology and pathology to stimulate research on therapeutic targeting NPY signaling in order to combat inflammatory skin diseases.

Expression of hypoxia inducible factor-dependent Neuropeptide Y Receptors Y1 and Y5 sensitizes hypoxic cells to NPY stimulation

Neuropeptide Y (NPY) is an abundant neurohormone in the central and peripheral nervous system involved in feeding behavior, energy balance, nociception, and anxiety. Several NPY receptor (NPYR) subtypes display elevated expression in many cancers including in breast tumors where it is exploited for imaging and diagnosis. Here, we address how hypoxia, a common feature of the tumor microenvironment, influences the expression of the NPYRs. We show that NPY1R and NPY5R mRNA abundance is induced by hypoxia in a hypoxia inducible factor (HIF)-dependent manner in breast cancer cell lines MCF7 and MDA-MB-231. We demonstrate that HIFs bind to several genomic regions upstream of the NPY1R and NPY5R transcription start sites. In addition, the MAPK/ERK pathway is activated more rapidly upon NPY5R stimulation in hypoxic cells compared with normoxic cells. This pathway requires insulin-like growth factor 1 receptor (IGF1R) activity in normoxia, but not in hypoxic cells, which display resistance to the radiosensitizer and IGF1R inhibitor AG1024. Furthermore, hypoxic cells proliferate and migrate more when stimulated with NPY relative to normoxic cells and exhibit a more robust response to a Y5-specific agonist. Our data suggest that hypoxia-induced NPYRs render hypoxic cells more sensitive to NPY stimulation. Considering that breast tissue receives a constant supply of NPY, hypoxic breast tumors are the perfect storm for hyperactive NPYR. This study not only highlights a new relationship between the HIFs and NPYR expression and activity but may inform the use of chemotherapeutics targeting NPYRs and hypoxic cells.

Intracolonic Neuropeptide Y Y1 Receptor Inhibition Attenuates Intestinal Inflammation in Murine Colitis and Cytokine Release in IBD Biopsies

We have demonstrated that neuropeptide Y (NPY) can regulate pro-inflammatory signaling in the gut via cross-talk with the pro-inflammatory cytokine tumor necrosis factor (TNF). Here, we investigated if selective blocking of NPY receptors, NPY1R or NPY2R, using small molecule non-peptide antagonists (BIBP-3222 for NPY1R and BIIE-0246 for NPY2R) in the colon could attenuate intestinal inflammation by lowering TNF levels (BIBP - N-[(1R)]-4-[(Aminoiminomethyl)amino-1-[[[(4-hydroxyphenyl)methyl]amino]carbonyl]butyl-α-phenylbenzeneacetamide; BIIE - N-[(1S)-4-[(Aminoiminomethyl)amino]-1-[[[2-(3,5-dioxo-1,2-diphenyl-1,2,4-triazolidin-4-yl)ethyl]amino]carbonyl]butyl]-1-[2-[4-(6,11-dihydro-6-oxo-5H-dibenz[b,e]azepin-11-yl)-1-piperazinyl]-2-oxoethyl]-cyclopentaneacetamide). Colitis was induced using dextran sodium sulfate in drinking water for 7 days, or by adoptive T-cell transfer in RAG-/- mice. Colonic biopsies from healthy subjects (n = 10) and IBD patients (n = 34, UC = 20, CD = 14) were cultured ex vivo in presence or absence of NPY antagonists (100 µM, 20 h), and cytokine release into culture supernatants was measured by ELISA. Intracolonic administration of BIBP (but not BIIE) significantly reduced clinical, endoscopic, and histological scores, and serum TNF, interleukin (IL)-6, and IL-12p70 in DSS colitis; it also significantly attenuated histological damage and serum IL-6 in T-cell colitis (P < .05). Intracolonic administration of BIBP significantly reduced TNF and interferon (IFN)-γ release from UC biopsies, whereas BIIE downregulated only IFN-γ (P < .05). BIBP significantly reduced TNF and interferon (IFN)-γ release from UC biopsies, whereas BIIE downregulated only IFN-γ (P < .05). Our data suggest a promising therapeutic value for NPY1R inhibition in alleviating intestinal inflammation in UC, possibly as enemas to IBD patients.

Neuropeptide Y Reduces Nasal Epithelial T2R Bitter Taste Receptor-Stimulated Nitric Oxide Production

Bitter taste receptors (T2Rs) are G-protein-coupled receptors (GPCRs) expressed on the tongue but also in various locations throughout the body, including on motile cilia within the upper and lower airways. Within the nasal airway, T2Rs detect secreted bacterial ligands and initiate bactericidal nitric oxide (NO) responses, which also increase ciliary beat frequency (CBF) and mucociliary clearance of pathogens. Various neuropeptides, including neuropeptide tyrosine (neuropeptide Y or NPY), control physiological processes in the airway including cytokine release, fluid secretion, and ciliary beating. NPY levels and/or density of NPYergic neurons may be increased in some sinonasal diseases. We hypothesized that NPY modulates cilia-localized T2R responses in nasal epithelia. Using primary sinonasal epithelial cells cultured at air–liquid interface (ALI), we demonstrate that NPY reduces CBF through NPY2R activation of protein kinase C (PKC) and attenuates responses to T2R14 agonist apigenin. We find that NPY does not alter T2R-induced calcium elevation but does reduce T2R-stimulated NO production via a PKC-dependent process. This study extends our understanding of how T2R responses are modulated within the inflammatory environment of sinonasal diseases, which may improve our ability to effectively treat these disorders.

The Role of Neuropeptides in Pathogenesis of Dry Dye

Neuropeptides are known as important mediators between the nervous and immune systems. Recently, the role of the corneal nerve in the pathogenesis of various ocular surface diseases, including dry eye disease, has been highlighted. Neuropeptides are thought to be important factors in the pathogenesis of dry eye disease, as suggested by the well-known role between the nervous and immune systems, and several recently published studies have elucidated the previously unknown pathogenic mechanisms involved in the role of the neuropeptides secreted from the corneal nerves in dry eye disease. Here, we reviewed the emerging concept of neurogenic inflammation as one of the pathogenic mechanisms of dry eye disease, the recent results of related studies, and the direction of future research.

Metabolic Hormones Modulate Macrophage Inflammatory Responses

Simple Summary

Macrophages are a type of immune cell which play an important role in the development of cancer. Obesity increases the risk of cancer and obesity also causes disruption to the normal levels of hormones that are produced to coordinate metabolism. Recent research now shows that these metabolic hormones also play important roles in macrophage immune responses and so through macrophages, disrupted metabolic hormone levels may promote cancer. This review article aims to highlight and summarise these recent findings so that the scientific community may better understand how important this new area of research is, and how these findings can be capitalised on for future scientific studies.

Abstract

Macrophages are phagocytotic leukocytes that play an important role in the innate immune response and have established roles in metabolic diseases and cancer progression. Increased adiposity in obese individuals leads to dysregulation of many hormones including those whose functions are to coordinate metabolism. Recent evidence suggests additional roles of these metabolic hormones in modulating macrophage inflammatory responses. In this review, we highlight key metabolic hormones and summarise their influence on the inflammatory response of macrophages and consider how, in turn, these hormones may influence the development of different cancer types through the modulation of macrophage functions.

Regulation of neuropeptide Y in body microenvironments and its potential application in therapies: a review

Neuropeptide Y (NPY), one of the most abundant neuropeptides in the body, is widely expressed in the central and peripheral nervous systems and acts on the cardiovascular, digestive, endocrine, and nervous systems. NPY affects the nutritional and inflammatory microenvironments through its interaction with immune cells, brain-derived trophic factor (BDNF), and angiogenesis promotion to maintain body homeostasis. Additionally, NPY has great potential for therapeutic applications against various diseases, especially as an adjuvant therapy for stem cells. In this review, we discuss the research progress regarding NPY, as well as the current evidence for the regulation of NPY in each microenvironment, and provide prospects for further research on related diseases.

Analysis of the transcriptional activity of genes of neuropeptides and their receptors in the blood of patients with thyroid pathology

The thyroid hormone plays a vital role in the development and maturation of the nervous system not only during prenatal and perinatal age but also in adults. “Peripheral marker hypothesis” revealed that gene expression changes in some regions of the brain are reflected into the peripheral blood lymphocytes. The objective of the study was to investigate changes in the gene expression profile of neuropeptides and their receptors in patients with different forms of thyroid pathology. One hundred fifty-three patients with thyroid pathology were enrolled in the study. They were divided into three groups: group 1 included 16 patients with postoperative hypothyroidism, group 2 included 65 patients with hypothyroidism resulting from autoimmune thyroiditis (AIT), and group 3 included 72 patients with AIT and elevated levels of anti-thyroglobulin (anti-Tg) and anti-thyroid peroxidase (anti-TPO) antibodies in the serum. We used a pathway-specific polymerase chain reaction (PCR) array (RT² Profiler™ PCR Array Human Neurotrophins & Receptors, QIAGEN, Germany) to identify and verify neuropeptides and receptors pathway-focused gene expression in 12 individuals that were randomly selected from each group using real-time PCR. Our research identified that patients with postoperative hypothyroidism had a considerably increased expression of NPY1R, NTSR1, and NPY4R. The patients with hypothyroidism caused by autoimmune thyroiditis had considerably lower expression of NTSR1, while the expression of NPY1R increased. The mRNA levels of NPY2R and PNOC increased in the patients with elevated levels of autoantibodies anti-Tg and anti-TPO in the serum, and mRNA levels of NPY1R and NTSR1 decreased in this group of patients.

Current views on neuropeptides in atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease involving skin barrier dysfunction and immune imbalance. However, the mechanism of AD is not clear completely and may be related to heredity and environment. Neuropeptides are a class of peptides secreted by nerve endings, they may play roles in promoting vasodilation, plasma extravasation, chemotaxis of inflammatory cells and mediating pruritus. Since itching and immune cell infiltration are the main manifestations of atopic dermatitis, to further investigate the impact of neuropeptides on AD, our review summarized the mechanisms of several common neuropeptides in AD and hypothesized that neuropeptides may be the novel potential targets in AD treatment.

Melanocortin 5 Receptor Expression and Recovery of Ocular Immune Privilege after Uveitis

Purpose: The therapeutic use of the RPE-neuropeptide α-MSH suppresses experimental autoimmune uveitis (EAU). This suppression is partially through the α-MSH melanocortin 5 receptor (MC5r). Therefore, we examined the possible role of MC5r-expression in the recovery of RPE suppression of phagolysosome-activation in macrophages following α-MSH-treatment of EAUMethods: The conditioned media of cultured in situ RPE-eyecup from α-MSH-treated EAU wild-type and MC5r(-/-) mice were used to treat macrophages to assay for phagolysosome activation.Results: MC5r(-/-) mice treated with α-MSH recovered from EAU, but with greater retinal damage, and the RPE suppressed phagolysosome activation in wild type but not in MC5r(-/-) macrophages. In addition, α-MSH did not suppress phagolysosome activation in MC5r(-/-) macrophages, and resting-MC5r(-/-) macrophages had augmented phagocytic activity.Conclusion: α-MSH treatment of EAU mediates a MC5r-dependent recovery of RPE suppression of phagolysosome activation in macrophages possibly altering antigen processing and presentation. Also, MC5r-expression helps protect the retina from inflammatory damage. In addition, MC5r-expression is important in the homeostatic maintenance of phagosome-maturation within macrophages.

Integrating neuronal involvement into the immune and genetic paradigm of vitiligo

In this review we show how the neuronal theory is relevant to the convergence theory for the mechanism causing vitiligo, especially the segmental type. Neuropeptides and neurotransmitters, such as neuropeptide Y and dopamine, can be central to the pathological mechanisms of melanocyte destruction. They link into a bidirectional network connecting cutaneous nerves, the neuroendocrine axis and the immune system, and through their local influence on cutaneous inflammation, to the antigen-specific regulatory T cells and the chemokine ligand type 9/chemokine receptor type 1 axis, which is thought to be the final pathway for melanocyte destruction.

Neuropeptide Y Is an Immunomodulatory Factor: Direct and Indirect

Neuropeptide Y (NPY), which is widely distributed in the nervous system, is involved in regulating a variety of biological processes, including food intake, energy metabolism, and emotional expression. However, emerging evidence points to NPY also as a critical transmitter between the nervous system and immune system, as well as a mediator produced and released by immune cells. In vivo and in vitro studies based on gene-editing techniques and specific NPY receptor agonists and antagonists have demonstrated that NPY is responsible for multifarious direct modulations on immune cells by acting on NPY receptors. Moreover, via the central or peripheral nervous system, NPY is closely connected to body temperature regulation, obesity development, glucose metabolism, and emotional expression, which are all immunomodulatory factors for the immune system. In this review, we focus on the direct role of NPY in immune cells and particularly discuss its indirect impact on the immune response.

Immune Dysfunction in Uremia 2020

Cardiovascular disease and infections are major causes for the high incidence of morbidity and mortality of patients with chronic kidney disease. Both complications are directly or indirectly associated with disturbed functions or altered apoptotic rates of polymorphonuclear leukocytes, monocytes, lymphocytes, and dendritic cells. Normal responses of immune cells can be reduced, leading to infectious diseases or pre-activated/primed, giving rise to inflammation and subsequently to cardiovascular disease. This review summarizes the impact of kidney dysfunction on the immune system. Renal failure results in disturbed renal metabolic activities with reduced renin, erythropoietin, and vitamin D production, which adversely affects the immune system. Decreased kidney function also leads to reduced glomerular filtration and the retention of uremic toxins. A large number of uremic toxins with detrimental effects on immune cells have been identified. Besides small water-soluble and protein-bound compounds originating from the intestinal microbiome, several molecules in the middle molecular range, e.g., immunoglobulin light chains, retinol-binding protein, the neuropeptides Met-enkephalin and neuropeptide Y, endothelin-1, and the adipokines leptin and resistin, adversely affect immune cells. Posttranslational modifications such as carbamoylation, advanced glycation products, and oxidative modifications contribute to uremic toxicity. Furthermore, high-density lipoprotein from uremic patients has an altered protein profile and thereby loses its anti-inflammatory properties.

Neuroimmune crosstalk in the pathophysiology of hypertension

Hypertension is an important risk factor for cardiovascular morbidity and mortality and for events such as myocardial infarction, stroke, heart failure and chronic kidney disease and is a major determinant of disability-adjusted life-years. Despite the importance of hypertension, the pathogenesis of essential hypertension, which involves the complex interaction of several mechanisms, is still poorly understood. Evidence suggests that interplay between bone marrow, microglia and immune mediators underlies the development of arterial hypertension, in particular through mechanisms involving cytokines and peptides, such as neuropeptide Y, substance P, angiotensin II and angiotensin-(1-7). Chronic psychological stress also seems to have a role in increasing the risk of hypertension, probably through the activation of neuroimmune pathways. In this Review, we summarize the available data on the possible role of neuroimmune crosstalk in the origin and maintenance of arterial hypertension and discuss the implications of this crosstalk for recovery and rehabilitation after cardiac and cerebral injuries.

The effects of IVIg therapy on serum levels of neuropeptide Y and cytokines in Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is a common acute immune-mediated inflammatory disorder affecting the peripheral nervous system (PNS) of humans. Studies in humans and in animal models revealed that neuropeptide Y (NPY) levels are altered in some neurodegenerative and neuroimmune disorders. Herein, we investigated the levels of NPY and cytokines in the serum of GBS patients and explored the roles of NPY in the disease severity and its short-term prognosis.

METHODS

Twenty patients with GBS (case group) and twenty healthy individuals (control group) were enrolled in this study. NPY levels were analyzed by enzyme-linked immunosorbent assay (ELISA). The levels of pro- and anti-inflammatory cytokines (including interferon-γ (IFN-γ), interleukin (IL)-4, IL-10, IL-12p70, IL-17A, and tumor necrosis factor-α (TNF-α)) were analyzed using cytometric beads array (CBA). The clinical characteristics, disease severity, and short-term prognosis were compared between the two groups.

RESULTS

Compared with the control group, the levels of NPY and cytokines were significantly increased in the serum of patients with GBS. NPY levels in the serum of GBS patients were correlated with the disease severity.

CONCLUSION

Our results suggest that NPY and cytokines are involved in the pathogenesis of GBS. The levels of NPY can help to predict the severity of the disease.

Genetic and Molecular Biology of Multiple Sclerosis Among Iranian Patients: An Overview

Multiple sclerosis (MS) is one if the common types of autoimmune disorders in developed countries. Various environmental and genetic factors are associated with initiation and progression of MS. It is believed that the life style changes can be one of the main environmental risk factors. The environmental factors are widely studied and reported, whereas minority of reports have considered the role of genetic factors in biology of MS. Although Iran is a low-risk country in the case of MS prevalence, it has been shown that there was a dramatically rising trend of MS prevalence among Iranian population during recent decades. Therefore, it is required to assess the probable MS risk factors in Iran. In the present study, we summarized all of the reported genes until now which have been associated with MS susceptibility among Iranian patients. To clarify the probable molecular biology of MS progression, we categorized these reported genes based on their cellular functions. This review paves the way of introducing a specific population-based diagnostic panel of genetic markers among the Iranian population for the first time in the world.

Roles of Neuropeptide Y in Neurodegenerative and Neuroimmune Diseases

Neuropeptide Y (NPY) is a neurotransmitter or neuromodulator that mainly exists in the nervous system. It plays a neuroprotective role in organisms and widely participates in the regulation of various physiological processes in vivo. Studies in both humans and animal models have been revealed that NPY levels are altered in some neurodegenerative and neuroimmune disorders. NPY plays various roles in these diseases, such as exerting a neuroprotective effect, increasing trophic support, decreasing excitotoxicity, regulating calcium homeostasis, and attenuating neuroinflammation. In this review, we will focus on the roles of NPY in the pathological mechanisms of neurodegenerative and neuroimmune diseases, highlighting NPY as a potential therapeutic target in these diseases.

Elevated Neuropeptide Y in Endothelial Dysfunction Promotes Macrophage Infiltration and Smooth Muscle Foam Cell Formation

Endothelial dysfunction has been linked to vascular inflammation and foam cell formation but the underlying mechanisms still remain unclear. We sought to define the factors inducing inflammation and smooth muscle foam cell formation under endothelial dysfunction using endothelial nitric oxide synthase (eNOS)-deficient mice. Vascular smooth muscle cells (VSMCs) from eNOS-deficient mice displayed increased expression of macrophage-related genes and elevated lipid uptake. Neuropeptide Y (NPY) was upregulated in the aorta from the eNOS-deficient mice and promoted macrophage chemotaxis toward VSMCs while enhancing the activity of matrix metalloproteinase-3. Notably, NPY induced lipid uptake in VSMCs, facilitating smooth muscle foam cell formation, in association with enhanced expression of genes related to modified low-density lipoprotein uptake and macrophages. NPY was augmented by inflammatory pentraxin 3 (PTX3) in VSMCs. PTX3 enhanced macrophage migratory capacity through the NPY/neuropeptide Y receptor axis and this effect was attenuated by pharmacological inhibition with a receptor-specific antagonist. These observations suggest that endothelial dysfunction leads to the elevation of NPY that amplifies vascular inflammation by increasing inflammatory cell chemotaxis and triggers smooth muscle foam cell formation.

Immunohistochemical analysis of the mouse celiac ganglion: An integrative relay station of the peripheral nervous system

Celiac ganglia are important sites of signal integration and transduction. Their complex neurochemical anatomy has been studied extensively in guinea pigs but not in mice. The goal of this study was to provide detailed neurochemical characterization of mouse celiac ganglia and noradrenergic nerves in two target tissues, spleen and stomach. A vast majority of mouse celiac neurons express a noradrenergic phenotype, which includes tyrosine hydroxylase (TH), vesicular monoamine transporter 2, and the norepinephrine transporter. Over 80% of these neuron also express neuropeptide Y (NPY), and this coexpression is maintained by dissociated neurons in culture. Likewise, TH and NPY were colocalized in noradrenergic nerves throughout the spleen and in stomach blood vessels. Somatostatin was not detected in principal neurons but did occur in small, TH-negative cells presumed to be interneurons and in a few varicose nerve fibers. Cholinergic nerves provided the most abundant input to the ganglia, and small percentages of these also contained nitric oxide synthase or vasoactive intestinal polypeptide. A low-to-moderate density of nerves also stained separately for the latter markers. Additionally, nerve bundles and varicose nerve fibers containing the sensory neuropeptides, calcitonin gene-related polypeptide, and substance P, occurred at variable density throughout the ganglia. Collectively, these findings demonstrate that principal neurons of mouse celiac ganglia have less neurochemical diversity than reported for guinea pig and other species but receive input from nerves expressing an array of neurochemical markers. This profile suggests celiac neurons integrate input from many sources to influence target tissues by releasing primarily norepinephrine and NPY.

In silico prediction reveals the existence of potential bioactive neuropeptides produced by the human gut microbiota

This work reports on a large-scale potential neuropeptide activity screening in human gut microbiomes deposited in public databases. In our experimental approach, the sequences of the bioactive peptides collected in the MAHMI database, mainly predicted as immunomodulatory or antitumoral, were crossed with those of the neuroactive/digestive peptides. From 91,325,790 potential bioactive peptides, only 581 returned a match when crossed against the 5949 neuroactive peptides from the NeuroPep database and the 15 digestive hormones. Relevant bacterial taxa, such as Ruminococcus sp., Clostridium sp. were found among the main producers of the matching sequences, and many of the matches corresponded to adiponectin and the hormone produced by adipocites, which is involved in glucose homeostasis. These results show, for the first time, the presence of potentially bioactive peptides produced by gut microbiota members over the nervous cells, most notably, peptides with already predicted immunomodulatory or anti-inflammatory activity. Classical (Lactobacillus sp.) and next-generation (Faecalibacterium sp.) probiotics are shown to produce these peptides, which are proposed as a potential mechanism of action of psychobiotics. Our previous experimental results showed that many of these peptides were active when incubated with immune cells, such as dendritic cells, so their effect over the nervous system innervating the gut mucosa holds significant potential and should be explored.

Pulmonary phagocyte-derived NPY controls the pathology of severe influenza virus infection

Crosstalk between the autonomic nervous system and the immune system by means of the sympathetic and parasympathetic pathways is a critical process in host defence. Activation of the sympathetic nervous system results in the release of catecholamines as well as neuropeptide Y (NPY). Here, we investigated whether phagocytes are capable of the de novo production of NPY, as has been described for catecholamines. We show that the synthesis of NPY and its Y1 receptor (Y1R) is increased in phagocytes in lungs following severe influenza virus infection. The genetic deletion of Npy or Y1r specifically in phagocytes greatly improves the pathology of severe influenza virus infection, which is characterized by excessive virus replication and pulmonary inflammation. Mechanistically, it is the induction of suppressor of cytokine signalling 3 (SOCS3) via NPY-Y1R activation that is responsible for impaired antiviral response and promoting pro-inflammatory cytokine production, thereby enhancing the pathology of influenza virus infection. Thus, direct regulation of the NPY-Y1R-SOCS3 pathway on phagocytes may act as a fine-tuner of an innate immune response to virus infection, which could be a therapeutic target for lethal influenza virus infection.

The Neuropeptides of Ocular Immune Privilege, α-MSH and NPY, Suppress Phagosome Maturation in Macrophages

The ocular microenvironment has evolutionarily adapted several mechanisms of immunosuppression to minimize the induction of inflammation. Neuropeptides produced by the retinal pigment epithelial cells regulate macrophage activity. Two neuropeptides, α-melanocyte–stimulating hormone (α -MSH) and neuropeptide Y (NPY), are constitutively expressed by the retinal pigment epithelial cells. Together these two neuropeptides induce anti-inflammatory cytokine production in endotoxin-stimulated macrophages and suppress phagocytosis of unopsonized bioparticles. These neuropeptides do not suppress the phagocytosis of opsonized bioparticles; however, they do suppress phagolysosome activation or formation. In this report, we studied the possibility that α-MSH with NPY suppress phagosome maturation within macrophages using opsonized OVA-coated magnetic beads to isolate and analyze the phagosomes. The magnetic bead–containing intercellular vesicles were isolated and assayed for Rab5, Rab7, LAMP1, Ia^d, and OVA. The macrophages cotreated with α-MSH and NPY were suppressed in Rab7 recruitment to the phagosome with suppression in LAMP1 expression but not in Ia^d expression. The results demonstrated that the α-MSH/NPY cotreatment suppressed phagosome maturation. In addition, the a-MSH/NPY–cotreated macrophages were suppressed in their ability to Ag stimulate CD4⁺ T cell proliferation. These results imply a potential mechanism of ocular immune privilege to divert Ag processing to prevent autoreactive effector T cells from binding their target cognate Ag within the ocular microenvironment.

Interplay between sympathetic nervous system and inflammation in aseptic loosening of hip joint replacement

Inflammation is a common symptom in joint disorders such as rheumatoid arthritis, osteoarthritis (OA) and implant aseptic loosening (AL). The sympathetic nervous system is well known to play a critical role in regulating inflammatory conditions, and imbalanced sympathetic activity has been observed in rheumatoid arthritis. In AL it is not clear whether the sympathetic nervous system is altered. In this study we evaluated the systemic and local profile of neuroimmune molecules involved in the interplay between the sympathetic nervous system and the periprosthetic inflammation in hip AL. Our results showed that periprosthetic inflammation does not trigger a systemic response of the sympathetic nervous system, but is mirrored rather by the impairment of the sympathetic activity locally in the hip joint. Moreover, macrophages were identified as key players in the local regulation of inflammation by the sympathetic nervous system in a process that is implant debris-dependent and entails the reduction of both adrenergic and Neuropetide Y (NPY)-ergic activity. Additionally, our results showed a downregulation of semaphorin 3A (SEMA3A) that may be part of the mechanism sustaining the periprosthetic inflammation. Overall, the local sympathetic nervous system emerges as a putative target to mitigate the inflammatory response to debris release and extending the lifespan of orthopedic implants.

When Clarity Is Crucial: Regulating Ocular Surface Immunity

The ocular surface is a unique mucosal immune compartment in which anatomical, physiological, and immunological features act in concert to foster a particularly tolerant microenvironment. These mechanisms are vital to the functional competence of the eye, a fact underscored by the devastating toll of excessive inflammation at the cornea - blindness. Recent data have elucidated the contributions of specific anatomical components, immune cells, and soluble immunoregulatory factors in promoting homeostasis at the ocular surface. We highlight research trends at this distinctive mucosal barrier and identify crucial gaps in our current knowledge.

Do Neuroendocrine Peptides and Their Receptors Qualify as Novel Therapeutic Targets in Osteoarthritis?

Joint tissues like synovium, articular cartilage, meniscus and subchondral bone, are targets for neuropeptides. Resident cells of these tissues express receptors for various neuroendocrine-derived peptides including proopiomelanocortin (POMC)-derived peptides, i.e., α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropin (ACTH) and β-endorphin (β-ED), and sympathetic neuropeptides like vasoactive intestinal peptide (VIP) and neuropeptide y (NPY). Melanocortins attained particular attention due to their immunomodulatory and anti-inflammatory effects in several tissues and organs. In particular, α-MSH, ACTH and specific melanocortin-receptor (MCR) agonists appear to have promising anti-inflammatory actions demonstrated in animal models of experimentally induced arthritis and osteoarthritis (OA). Sympathetic neuropeptides have obtained increasing attention as they have crucial trophic effects that are critical for joint tissue and bone homeostasis. VIP and NPY are implicated in direct and indirect activation of several anabolic signaling pathways in bone and synovial cells. Additionally, pituitary adenylate cyclase-activating polypeptide (PACAP) proved to be chondroprotective and, thus, might be a novel target in OA. Taken together, it appears more and more likely that the anabolic effects of these neuroendocrine peptides or their respective receptor agonists/antagonists may be exploited for the treatment of patients with inflammatory and degenerative joint diseases in the future.

Anxiety, Depression, and the Microbiome: A Role for Gut Peptides

The complex bidirectional communication between the gut and the brain is finely orchestrated by different systems, including the endocrine, immune, autonomic, and enteric nervous systems. Moreover, increasing evidence supports the role of the microbiome and microbiota-derived molecules in regulating such interactions; however, the mechanisms underpinning such effects are only beginning to be resolved. Microbiota-gut peptide interactions are poised to be of great significance in the regulation of gut-brain signaling. Given the emerging role of the gut-brain axis in a variety of brain disorders, such as anxiety and depression, it is important to understand the contribution of bidirectional interactions between peptide hormones released from the gut and intestinal bacteria in the context of this axis. Indeed, the gastrointestinal tract is the largest endocrine organ in mammals, secreting dozens of different signaling molecules, including peptides. Gut peptides in the systemic circulation can bind cognate receptors on immune cells and vagus nerve terminals thereby enabling indirect gut-brain communication. Gut peptide concentrations are not only modulated by enteric microbiota signals, but also vary according to the composition of the intestinal microbiota. In this review, we will discuss the gut microbiota as a regulator of anxiety and depression, and explore the role of gut-derived peptides as signaling molecules in microbiome-gut-brain communication. Here, we summarize the potential interactions of the microbiota with gut hormones and endocrine peptides, including neuropeptide Y, peptide YY, pancreatic polypeptide, cholecystokinin, glucagon-like peptide, corticotropin-releasing factor, oxytocin, and ghrelin in microbiome-to-brain signaling. Together, gut peptides are important regulators of microbiota-gut-brain signaling in health and stress-related psychiatric illnesses.

New immunomodulatory role of neuropeptide Y (NPY) in Salmo salar leucocytes

Neuropeptide Y (NPY) plays different roles in mammals such as: regulate food intake, memory retention, cardiovascular functions, and anxiety. It has also been shown in the modulation of chemotaxis, T lymphocyte differentiation, and leukocyte migration. In fish, NPY expression and functions have been studied but its immunomodulatory role remains undescribed. This study confirmed the expression and synthesis of NPY in S. salar under inflammation, and validated a commercial antibody for NPY detection in teleost. Additionally, immunomodulatory effects of NPY were assayed in vitro and in vivo. Phagocytosis and superoxide anion production in leukocytes and SHK cells were induced under stimulation with a synthetic peptide. IL-8 mRNA was selectively and strongly induced in the spleen, head kidney, and isolated cells, after in vivo challenge with NPY. All together suggest that NPY is expressed in immune tissues and modulates the immune response in teleost fish.

Traumatic stress-induced persistent changes in DNA methylation regulate neuropeptide Y expression in rat jejunum

BACKGROUND

Stress-induced chronic neuropsychiatric conditions such as anxiety are often co-morbid with gastrointestinal malfunctions. While we find enduring anxiety-like symptoms following minimal traumatic brain injury (MTBI) in rats, gastrointestinal consequences of MTBI remain elusive.

METHODS

In this study, we examined the effects of MTBI on a major gut peptide, neuropeptide Y (NPY) and gut motility. DNA methylation was studied as a possible epigenetic mechanism operative in the regulation of NPY expression in the gut.

KEY RESULTS

Minimal traumatic brain injury reduced the gut motility 48 hours and 30 days after trauma. The expression of DNA methyltransferase isoforms (DNMT1, DNMT3a, and DNMT3b) was altered in the jejunum 48 hours and 30 days after MTBI. However, the mRNA levels of growth arrest and DNA damage 45 (GADD45) isoforms, GADD45a, and GADD45b, which are believed to be involved in active DNA demethylation, initially decreased at 48 hours but subsequently increased after 30 days of trauma. Similarly, DNA hypomethylation at the NPY promoter region in the jejunum was correlated with the increase in NPY mRNA and protein levels 30 days post-trauma. On the other hand, DNA hypomethylation at 48 hours was associated with a decline in NPY expression. Treatment with 5-azacytidine (5-AzaC), a DNMT inhibitor, retarded DNA methylation and restored the NPY mRNA levels in the jejunum of MTBI-induced rats.

CONCLUSIONS & INFERENCES

These results suggest that DNA demethylation could be operative as an epigenetic mechanism in the long-term regulation of NPY gene expression to alter the gut motility during traumatic stress.

Multiple Sclerosis: Implications of Obesity in Neuroinflammation

Since the discovery of the remarkable properties of adipose tissue as a metabolically active organ, several evidences on the possible link between obesity and the pathogenesis of multiple sclerosis (MS) have been gathered. Obesity in early life, mainly during adolescence, has been proposed as a relevant risk factor for late MS development. Moreover, once MS is initiated, obesity can contribute to increase disease severity by negatively influencing disease progress. Despite the fact that clinical data are not yet conclusive, many biochemical links have been recently disclosed. The "low-grade inflammation" that characterizes obesity can lead to neuroinflammation through different mechanisms, including choroid plexus and blood-brain barrier disruption. Furthermore, it is well known that resident immune cells of central nervous system and peripheral immune cells are involved in the pathogenesis of MS, and adipokines and neuropeptides such as neuropeptide Y may mediate the cross talk between them.

Association study of two functional single nucleotide polymorphisms of neuropeptide y gene with multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by brain inflammation, demyelination and axonal loss. Neuropeptide Y (NPY) has a critical role in the maintenance of homeostasis in the immune system and coping of stress condition. In the current study we analyzed 188 patients suffering from MS and 204 unrelated healthy controls for two functional single nucleotide polymorphisms (SNPs), NPY 20T>C (rs16139) and NPY -485T>C (rs16147) using PCR-RFLP and Mismatch PCR-RFLP methods. Our results demonstrated that homozygocity in the minor allele for NPY -485T>C polymorphism is associated with the MS risk in patients in compare with healthy controls (CC vs. TT, P=0.033; CC vs. TT+TC, P=0.02). In addition, by comparison with allele T, the frequency of NPY -485C allele was higher in cases than in control subjects and present increased risk of MS, but statistically significant was borderline (P=0.053). The stratification for disease progression revealed a significant difference in the allelic and genotypic distribution between subgroups of MS and controls. The frequency of the CC genotype and C allele was higher in the primary progressive MS patients when compared with control group (CC vs. TT, P=0.019; CC vs. TT+TC, P=0.008; C vs. T, P=0.022). In addition, the frequency of CC genotype was higher in the relapsing remitting MS patients when compared with control group (CC vs. TT, P=0.034; CC vs. TT+TC, P=0.016). Haplotype analysis demonstrated that the haplotype 3 (CT) is more common in RR MS (P=0.041), and PP MS (P=0.031) than control group. In conclusion, the obtained results demonstrate the probable role of NPY SNPs in susceptibility to MS within the Iranian population.

Experimental Piscine orthoreovirus infection mediates protection against pancreas disease in Atlantic salmon (Salmo salar)

Viral diseases are among the main challenges in farming of Atlantic salmon (Salmo salar). The most prevalent viral diseases in Norwegian salmon aquaculture are heart and skeletal muscle inflammation (HSMI) caused by Piscine orthoreovirus (PRV), and pancreas disease (PD) caused by Salmonid alphavirus (SAV). Both PRV and SAV target heart and skeletal muscles, but SAV additionally targets exocrine pancreas. PRV and SAV are often present in the same locations and co-infections occur, but the effect of this crosstalk on disease development has not been investigated. In the present experiment, the effect of a primary PRV infection on subsequent SAV infection was studied. Atlantic salmon were infected with PRV by cohabitation, followed by addition of SAV shedder fish 4 or 10 weeks after the initial PRV infection. Histopathological evaluation, monitoring of viral RNA levels and host gene expression analysis were used to assess disease development. Significant reduction of SAV RNA levels and of PD specific histopathological changes were observed in the co-infected groups compared to fish infected by SAV only. A strong correlation was found between histopathological development and expression of disease related genes in heart. In conclusion, experimentally PRV infected salmon are less susceptible to secondary SAV infection and development of PD.

Neuropeptides, Microbiota, and Behavior

The gut microbiota and the brain interact with each other through multiple bidirectional signaling pathways in which neuropeptides and neuroactive peptide messengers play potentially important mediator roles. Currently, six particular modes of a neuropeptide link are emerging. (i) Neuropeptides and neurotransmitters contribute to the mutual microbiota-host interaction. (ii) The synthesis of neuroactive peptides is influenced by microbial control of the availability of amino acids. (iii) The activity of neuropeptides is tempered by microbiota-dependent autoantibodies. (iv) Peptide signaling between periphery and brain is modified by a regulatory action of the gut microbiota on the blood-brain barrier. (v) Within the brain, gut hormones released under the influence of the gut microbiota turn into neuropeptides that regulate multiple aspects of brain activity. (vi) Cerebral neuropeptides participate in the molecular, behavioral, and autonomic alterations which the brain undergoes in response to signals from the gut microbiota.

An association between neuropeptide Y levels and leukocyte subsets in stress-exacerbated asthmatic mice

Neuropeptide Y (NPY) was recently proposed to be associated with stress and airway inflammation; however, this has rarely been studied in animal models of asthma. Twenty-four C57BL/6 mice were randomly divided into 3 groups of 8 each: naive control group, asthma group (with an established asthma model), and stressed asthma group (with established asthma and stress models). Bronchoalveolar lavage (BAL) fluid was collected for total cell counts using a hemocytometer and for cytological examinations by Wright stain. Differential inflammatory cell counts were performed to identify eosinophils, macrophages, neutrophils, and lymphocytes. NPY and corticosterone serum levels were determined with enzyme immunoassay kits. Stress was associated with increased airway inflammatory response, which was manifested by the accumulation of total leukocytes and eosinophils in the BAL fluid in comparison with the asthma and the control groups. The levels of NPY (p<0.05) and corticosterone (p<0.01) were elevated in the stressed asthma group in comparison with the control and asthma groups. The concentration of NPY and corticosterone positively correlated with the total leukocyte count (r=0.892, p<0.05 and r=0.937, p<0.01 respectively) and eosinophil numbers (r=0.806, p=0.053 and r=0.885, p<0.01 respectively). Stress may be associated with elevated peripheral NPY level, which was observed to be associated with exacerbated airway inflammation in asthmatic mice.

Epithelium-generated neuropeptide Y induces smooth muscle contraction to promote airway hyperresponsiveness

Asthma is one of the most common chronic diseases globally and can be divided into presenting with or without an immune response. Current therapies have little effect on nonimmune disease, and the mechanisms that drive this type of asthma are poorly understood. Here, we have shown that loss of the transcription factors forkhead box P1 (Foxp1) and Foxp4, which are critical for lung epithelial development, in the adult airway epithelium evokes a non-Th2 asthma phenotype that is characterized by airway hyperresponsiveness (AHR) without eosinophilic inflammation. Transcriptome analysis revealed that loss of Foxp1 and Foxp4 expression induces ectopic expression of neuropeptide Y (Npy), which has been reported to be present in the airways of asthma patients, but whose importance in disease pathogenesis remains unclear. Treatment of human lung airway explants with recombinant NPY increased airway contractility. Conversely, loss of Npy in Foxp1- and Foxp4-mutant airway epithelium rescued the AHR phenotype. We determined that NPY promotes AHR through the induction of Rho kinase activity and phosphorylation of myosin light chain, which induces airway smooth muscle contraction. Together, these studies highlight the importance of paracrine signals from the airway epithelium to the underlying smooth muscle to induce AHR and suggest that therapies targeting epithelial induction of this phenotype may prove useful in treatment of noneosinophilic asthma.

Obesity and brain inflammation: a focus on multiple sclerosis

The increase in prevalence of obesity in industrialized societies is an indisputable fact. However, the apparent passive role played by adipocytes, in pathophysiological terms, has been gradually substituted by a metabolically active performance, relevant to many biochemical mechanisms that may contribute to a chronic low-grade inflammatory status, which increasingly imposes itself as a key feature of obesity. This chronic inflammatory status will have to be integrated into the complex equation of many diseases in which inflammation plays a crucial role. Multiple sclerosis (MS) is a chronic inflammatory condition typically confined to the central nervous system, and many work has been produced to find possible points of contact between the biology of this immune-mediated disease and obesity. So far, clinical data are not conclusive, but many biochemical features have been recently disclosed. Brain inflammation has been implicated in some of the mechanisms that lead to obesity, which has also been recognized as an important player in inducing some degree of immune dysfunction. In this review, we collected evidence that allows establishing bridges between obesity and MS. After considering epidemiological controversies, we will focus on possible shared mechanisms, as well as on the potential contributions that disease-modifying drugs may have on this apparent relationship of mutual interference.