Role Of Vasoactive Intestinal Peptide Research Articles

The role of vasoactive intestinal peptide (VIP) in atropine-related inhibition of the progression of myopia

ObjectiveThis study aimed to investigate the potential involvement of vasoactive intestinal polypeptide (VIP) in myopia development and its contribution to the mechanism of action of the anti-myopia drug, atropine.MethodsThirty-three-week-old guinea pigs were randomly divided into normal control (NC, n = 10), monocularly form-deprived (FDM, n = 10), and FDM treated with 1% atropine (FDM + AT, n = 10) groups. The diopter and axial length were measured at 0, 2, and 4 weeks. Guinea pig eyeballs were removed at week four, fixed, and stained for morphological changes. Immunohistochemistry (IHC) and in situ hybridization (ISH) were performed to evaluate VIP protein and mRNA levels.ResultsThe FDM group showed an apparent myopic shift compared to the control group. The results of the H&E staining were as follows: the cells of the inner/outer nuclear layers and retinal ganglion cells were disorganized; the choroidal thickness (ChT), blood vessel lumen, and area were decreased; the sclera was thinner, with disordered fibers and increased interfibrillar space. IHC and ISH revealed that VIP's mRNA and protein expressions were significantly up-regulated in the retina of the FDM group. Atropine treatment attenuated FDM-induced myopic shift and fundus changes, considerably reducing VIP's mRNA and protein expressions.ConclusionsThe findings of elevated VIP mRNA and protein levels observed in the FDM group indicate the potential involvement of VIP in the pathogenesis and progression of myopia. The ability of atropine to reduce this phenomenon suggests that this may be one of the molecular mechanisms for atropine to control myopia.

Immunomodulatory role of vasoactive intestinal peptide and ghrelin in Oncorhynchus mykiss

Neuropeptides are a group of peptides derived from precursor proteins synthesized in neuronal and nonneuronal cells. The classical functions of neuropeptides have been extensively studied in mammals, including neuromodulation in the central nervous system, molecular signaling in the peripheral nervous system, and immunomodulation associated mainly with anti-inflammatory activity. In contrast, in teleosts, studies of the immunomodulatory function of these neuropeptides are limited. In Oncorhynchus mykiss, vasoactive intestinal peptide (VIP) mRNA sequences have not been cloned, and the role of VIP in modulating the immune system has not been studied. Furthermore, in relation to other neuropeptides with possible immunomodulatory function, such as ghrelin, there are also few studies. Therefore, in this work, we performed molecular cloning, identification, and phylogenetic analysis of three VIP precursor sequences (prepro-VIP1, VIP2 and VIP3) in rainbow trout. In addition, the immunomodulatory function of both neuropeptides was evaluated in an in vitro model using the VIP1 sequence identified in this work and a ghrelin sequence already studied in O. mykiss. The results suggest that the prepro-VIP2 sequence has the lowest percentage of identity with respect to the other homologous sequences and is more closely related to mammalian orthologous sequences. VIP1 induces significant expression of both pro-inflammatory (IFN-γ, IL-1β) and anti-inflammatory (IL-10 and TGF-β) cytokines, whereas ghrelin only induces significant expression of proinflammatory cytokines such as IL-6 and TNF-α.

Role of Vasoactive Intestinal Peptide in Mediating AntiInflammatory Response During Pregnancy: A Review

Role of Vasoactive Intestinal Peptide in Mediating AntiInflammatory Response During Pregnancy: A Review

Vasoactive intestinal peptide blockade suppresses tumor growth by regulating macrophage polarization and function in CT26 tumor-bearing mice

Macrophages are a major population of immune cells in solid cancers, especially colorectal cancers. Tumor-associated macrophages (TAMs) are commonly divided into M1-like (tumor suppression) and M2-like (tumor promotion) phenotypes. Vasoactive intestinal peptide (VIP) is an immunoregulatory neuropeptide with a potent anti-inflammatory function. Inhibition of VIP signaling has been shown to increase CD8+ T cell proliferation and function in viral infection and lymphoma. However, the role of VIP in macrophage polarization and function in solid tumors remains unknown. Here, we demonstrated that conditioned medium from CT26 (CT26-CM) cells enhanced M2-related marker and VIP receptor (VPAC) gene expression in RAW264.7 macrophages. VIP hybrid, a VIP antagonist, enhanced M1-related genes but reduced Mrc1 gene expression and increased phagocytic ability in CT26-CM-treated RAW264.7 cells. In immunodeficient SCID mice, VIP antagonist alone or in combination with anti-PD-1 antibody attenuated CT26 tumor growth compared with the control. Analysis of tumor-infiltrating leukocytes found that VIP antagonist increased M1/M2 ratios and macrophage phagocytosis of CT26-GFP cells. Furthermore, Vipr2 gene silencing or VPAC2 activation affected the polarization of CT26-CM-treated RAW264.7 cells. In conclusion, the inhibition of VIP signaling enhanced M1 macrophage polarization and macrophage phagocytic function, resulting in tumor regression in a CT26 colon cancer model.

Human CD4+CD45RA+ T Cells Behavior after In Vitro Activation: Modulatory Role of Vasoactive Intestinal Peptide.

Naїve CD4+ T cells, which suffer different polarizing signals during T cell receptor activation, are responsible for an adequate immune response. In this study, we aimed to evaluate the behavior of human CD4+CD45RA+ T cells after in vitro activation by anti-CD3/CD28 bead stimulation for 14 days. We also wanted to check the role of the VIP system during this process. The metabolic biomarker Glut1 was increased, pointing to an increase in glucose requirement whereas Hif-1α expression was higher in resting than in activated cells. Expression of Th1 markers increased at the beginning of activation, whereas Th17-associated biomarkers augmented after that, showing a pathogenic Th17 profile with a possible plasticity to Th17/1. Foxp3 mRNA expression augmented from day 4, but no parallel increases were observed in IL-10, IL-2, or TGFβ mRNA expression, meaning that these potential differentiated Treg could not be functional. Both VIP receptors were located on the plasma membrane, and expression of VPAC2 receptor increased significantly with respect to the VPAC1 receptor from day 4 of CD4+CD45RA+ T activation, pointing to a shift in VPAC receptors. VIP decreased IFNγ and IL-23R expression during the activation, suggesting a feasible modulation of Th17/1 plasticity and Th17 stabilization through both VPAC receptors. These novel results show that, without polarizing conditions, CD4+CD45RA+ T cells differentiate mainly to a pathogenic Th17 subset and an unpaired Treg subset after several days of activation. Moreover, they confirm the important immunomodulatory role of VIP, also on naїve Th cells, stressing the importance of this neuropeptide on lymphocyte responses in different pathological or non-pathological situations.

The Role of Vasoactive Intestinal Peptide and Mast Cells in the Regulatory Effect of Lactobacillus casei ATCC 393 on Intestinal Mucosal Immune Barrier.

Vasoactive intestinal peptide (VIP) plays an important role in the neuro-endocrine-immune system. Mast cells (MCs) are important immune effector cells. This study was conducted to investigate the protective effect of L. casei ATCC 393 on Enterotoxigenic Escherichia coli (ETEC) K88-induced intestinal mucosal immune barrier injury and its association with VIP/MC signaling by in vitro experiments in cultures of porcine mucosal mast cells (PMMCs) and in vivo experiments using VIP receptor antagonist (aVIP) drug. The results showed that compared with the ETEC K88 and lipopolysaccharides (LPS)-induced model groups, VIP pretreatment significantly inhibited the activation of MCs and the release of β-hexosaminidase (β-hex), histamine and tryptase. Pretreatment with aVIP abolished the protective effect of L. casei ATCC 393 on ETEC K88-induced intestinal mucosal immune barrier dysfunction in C57BL/6 mice. Also, with the blocking of VIP signal transduction, the ETEC K88 infection increased serum inflammatory cytokines, and the numbers of degranulated MCs in ileum, which were decreased by administration of L. casei ATCC 393. In addition, VIP mediated the regulatory effect of L. casei ATCC 393 on intestinal microbiota in mice. These findings suggested that VIP may mediate the protective effect of L.casei ATCC 393 on intestinal mucosal immune barrier dysfunction via MCs.

VIP Stabilizes the Cytoskeleton of Schlemm's Canal Endothelia via Reducing Caspase-3 Mediated ZO-1 Endolysosomal Degradation.

Objectives In glaucomatous eyes, the main aqueous humor (AH) outflow pathway is damaged by accumulated oxidative stress arising from the microenvironment, vascular dysregulation, and aging, which results in increased outflow resistance and ocular hypertension. Schlemm's canal (SC) serves as the final filtration barrier of the main AH outflow pathway. The present study is aimed at investigating the possible regulation of vasoactive intestinal peptide (VIP) on the cytoskeleton by stabilizing ZO-1 in SC. Methods Model of chronic ocular hypertension (COH) induced by episcleral venous cauterization was treated with topical VIP. The ultrastructure of junctions, ZO-1 levels, and permeability of the SC inner wall to FITC-dextran (70 kDa) were detected in the COH models. The F-actin distribution, F/G-actin ratio, and ZO-1 degradation pathway in human umbilical vein endothelial cells (HUVECs) and HEK 293 cells were investigated. Results ZO-1 in the outer wall of the SC was less than that in the inner wall. COH elicited junction disruption, ZO-1 reduction, and increased permeability of the SC inner wall to FITC-dextran in rats. ZO-1 plays an essential role in maintaining the F/G-actin ratio and F-actin distribution. VIP treatment attenuated the downregulation of ZO-1 associated with COH or H2O2-induced oxidative damage. In H2O2-stimulated HUVECs, the caspase-3 inhibitor prevents ZO-1 disruption. Caspase-3 activation promoted endolysosomal degradation of ZO-1. Furthermore, a decrease in caspase-3 activation and cytoskeleton redistribution was demonstrated in VIP + H2O2-treated cells. The knockdown of ZO-1 or the overexpression of caspase-3 blocked the effect of VIP on the cytoskeleton. Conclusion This study provides insights into the role of VIP in stabilizing the interaction between the actin cytoskeleton and cell junctions and may provide a promising targeted strategy for glaucoma treatment.

Non-medicine Methods of Treatment of Gastroesophageal Reflux Disease

Few decades away a problem of throwing of acidic gastric content into an esophagus was reduced to the concept of reflux-esophagitis. In-depth study of pathogenesis of a disease resulted in “gastroesophageal reflux disease” (GERD) term which is acknowledged as leading disease of digestive system in terms of frequency and dangerous complications. GERD formation is determined by influence of numerous factors, however, it is generally accepted, that it is mainly related to insufficiency of lower esophageal sphincter (LES). Also, role of vasoactive intestinal peptide (VIP) in regulation of functional state of LES is determined. In spite of success in field of pharmacology, number of GERD patients has no downward trend which mainstreams search for non-medicine treatment methods. Physical factors affecting pathological processes by influencing regulatory processes are among these methods. Goal of this study is elaboration, scientific justification and clinical implementation of natural and preformed physical factors and acupuncture in treatment of patients with gastroesophageal reflux disease. Materials and Investigation methods: Randomized placebo-controlled study included 137 patients with gastroesophageal reflux disease, 63 (46%) men and 74 (54%) women, at the age of 18 to 65. Investigation included patients with no contraindications for physiotherapy. Patients with Barrett’s esophagus, stricture of esophagus, esophagus ulcer have also been excluded from investigation. Patients were divided into 3 groups: Ist group – 40 GERD patients, including high-frequency electromagnetic field effect and general iodine bromine bathes. II nd group - 67 GERD patients passing acupuncture treatment course. Control group was comprised of 30 GERD patients, receiving placebo MEF therapy. Treatment was carried out without medicines. Therapeutic effectiveness of complex influence of microwave electromagnetic field therapy (MEF-therapy) applied to collar area alternated with general iodine-bromine bathes on clinical manifestations of GERD is determined. Treatment course contributed to reliable decrease of increased count of VIP – a neurotransmitter, regulating LES tonus. In term, it contributed to improve of functional state of LES, reliable decrease of reflux index, and, as a result, improvement of clinical and functional indicators. Estimation of clinical manifestations of a disease among patients of 2nd group displayed positive dynamics of clinical and functional indicators. Round-clock pH-monitoring of stomach and esophageal content shows reliable decreaseof transitory relaxations of LES during single acupuncture procedure and increase of pH of gastric content. Acupuncture course also resulted in decrease of elevated VIP numbers.

Vasoactive intestinal peptide axis is dysfunctional in patients with Graves\u2019 disease

Vasoactive intestinal peptide (VIP) is a neuropeptide with potent immunoregulatory properties. Reduced serum VIP levels and alterations in VIP receptors/signaling on immune cells have been associated with different inflammatory/autoimmune diseases. However, its role in autoimmune thyroid diseases (AITD) remains unknown. This study examined the interrelationship between VIP system, autoimmune background and thyroid hormones in peripheral immune cells in patients with AITD. Only Graves’ disease (GD) patients showed significantly lower serum VIP levels when compared to healthy subjects and to Hashimoto’s thyroiditis patients. Serum VIP levels were lower at the onset of GD, showing a significant negative correlation with thyroid hormone levels. The expression of VIP receptors, VPAC1 and VPAC2, was significantly upregulated in peripheral blood mononuclear cells (PBMC) from GD patients. There was an impairment of VIP signalling in these patients, probably attributable to a dysfunction of VPAC1 with preservation of VPAC2. The correlation between VPAC1 and thyroid hormone receptor expression in PBMC from healthy subjects was lost in GD patients. In summary, the VIP system is altered in peripheral immune cells of GD patients and this finding is associated with different thyroid hormone receptor patterns, showing a dynamic inter-regulation and a prominent role of VIP in this setting.

0163 Investigating the Role of Vasoactive Intestinal Peptide-Containing Neurons of the Ventromedal Preoptic Area in Sleep-Wake Control

Abstract Introduction A role for vasoactive intestinal peptide (VIP) in promoting rapid eye movement (REM) sleep has been suggested, but the anatomical location of the neurons that release VIP to promote REM sleep has not been identified. Here, we investigated the role of VIP-containing cell groups in the ventromedial preoptic area (VMPOVIP) in sleep-wake regulation. The VMPO has also previously been implicated in thermoregulation and the febrile response. Methods We first investigated the native firing activity of VMPOVIP neurons, over repeated sleep-wake cycles, using in vivo fiber photometry in VIP-ires-Cre mice. We next examined the afferent and efferent profile of this cell group using conditional retrograde (pseudotyped modified rabies) and anterograde (adeno-associated viral vector-based) tracers. We finally utilized a chemogenetic strategy to selectively activate VMPOVIP neurons cells while monitoring electroencephalogram/electromyogram activity and core body temperature, in order to determine their role in sleep-wake and thermoregulatory control. Results We found that VMPOVIP cells were predominantly and strikingly REM-active, that they received many synaptic inputs from surrounding hypothalamic regions (including the ventromedial hypothalamus, dorsomedial hypothalamus and the arcuate nucleus), and that they targeted established sleep-wake nodes, such as the ventrolateral preoptic nucleus, tuberomammillary nucleus, lateral hypothalamus and ventrolateral periaqueductal gray area. To our surprise, chemogenetic activation of the VMPOVIP cell population had little effect upon all measures of sleep-wake analysed and no effect upon core body temperature. Conclusion We conclude that VMPOVIP neurons do not promote REM sleep per se. However, their REM-active profile and anatomical connectivity suggest that these neurons may play a functional role in generating certain cardinal features of REM sleep, which is an active focus of on-going research in our laboratory. Support SRSF CDA #016-JP-17 to A.V. and NS073613, NS092652 and NS103161 to P.M.

Role of VIP and Sonic Hedgehog Signaling Pathways in Mediating Epithelial Wound Healing, Sensory Nerve Regeneration, and Their Defects in Diabetic Corneas.

Diabetic keratopathy, a sight-threatening corneal disease, comprises several symptomatic conditions including delayed epithelial wound healing, recurrent erosions, and sensory nerve (SN) neuropathy. We investigated the role of neuropeptides in mediating corneal wound healing, including epithelial wound closure and SN regeneration. Denervation by resiniferatoxin severely impaired corneal wound healing and markedly upregulated proinflammatory gene expression. Exogenous neuropeptides calcitonin gene-related peptide (CGRP), substance P (SP), and vasoactive intestinal peptide (VIP) partially reversed resiniferatoxin's effects, with VIP specifically inducing interleukin-10 expression. Hence, we focused on VIP and observed that wounding induced VIP and VIP type 1 receptor (VIPR1) expression in normal (NL) corneas, but not corneas from mice with diabetes mellitus (DM). Targeting VIPR1 in NL corneas attenuated corneal wound healing, dampened wound-induced expression of neurotrophic factors, and exacerbated inflammatory responses, while exogenous VIP had the opposite effects in DM corneas. Remarkably, wounding and diabetes also affected the expression of Sonic Hedgehog (Shh) in a VIP-dependent manner. Downregulating Shh expression in NL corneas decreased while exogenous Shh in DM corneas increased the rates of corneal wound healing. Furthermore, inhibition of Shh signaling dampened VIP-promoted corneal wound healing. We conclude that VIP regulates epithelial wound healing, inflammatory response, and nerve regeneration in the corneas in an Shh-dependent manner, suggesting a therapeutic potential for these molecules in treating diabetic keratopathy.

Role of vasoactive intestinal peptide in the progression of osteoarthritis through bone sclerosis and angiogenesis in subchondral bone

ObjectiveOsteoarthritis (OA) is a progressive joint disorder, with abnormal remodeling of subchondral bone linked to the disruption of cartilage metabolism. Nerves also play an important role in bone remodeling in OA progression, and vasoactive intestinal peptide (VIP), one of the neuropeptides, plays an important role in bone metabolism. The aim of this study was to analyze the expression pattern of VIP in subchondral bone, and its potential as a therapeutic target for OA progression. DesignThe pattern of VIP expression in the human tibia was histologically evaluated. The effect of VIP on angiogenesis was investigated using human umbilical vein endothelial cells (HUVECs). Knee OA was induced by the resection of the medial meniscotibial ligament in C57BL/6 mice. A VIP receptor antagonist was intraperitoneally administered postoperatively, and therapeutic effects were analyzed at 4 and 8 weeks. ResultsVIP expression in the subchondral bone increased as OA progressed in human tibia. VIP was also expressed in the vascular channels into the cartilage layer. The total length and branch points were significantly increased, due to the VIP receptor agonist in HUVECs. In OA mice, the VIP receptor antagonist could prevent cartilage degeneration and subchondral bone sclerosis. The Osteoarthritis Research Society International score in the VIP receptor antagonist group was significantly lower than in the control group. ConclusionVIP is involved in the progression of OA through its effect on subchondral bone sclerosis and angiogenesis. Inhibition of VIP signaling has the potential to be a therapeutic target to prevent OA progression.

Vasoactive Intestinal Peptide induces glucose and neutral amino acid uptake through mTOR signalling in human cytotrophoblast cells

The transport of nutrients across the placenta involves trophoblast cell specific transporters modulated through the mammalian target of rapamycin (mTOR). The vasoactive intestinal peptide (VIP) has embryotrophic effects in mice and regulates human cytotrophoblast cell migration and invasion. Here we explored the effect of VIP on glucose and System A amino acid uptake by human trophoblast-derived cells (Swan 71 and BeWo cell lines). VIP activated D-glucose specific uptake in single cytotrophoblast cells in a concentration-dependent manner through PKA, MAPK, PI3K and mTOR signalling pathways. Glucose uptake was reduced in VIP-knocked down cytotrophoblast cells. Also, VIP stimulated System A amino acid uptake and the expression of GLUT1 glucose transporter and SNAT1 neutral amino acid transporter. VIP increased mTOR expression and mTOR/S6 phosphorylation whereas VIP silencing reduced mTOR mRNA and protein expression. Inhibition of mTOR signalling with rapamycin reduced the expression of endogenous VIP and of VIP-induced S6 phosphorylation. Our findings support a role of VIP in the transport of glucose and neutral amino acids in cytotrophoblast cells through mTOR-regulated pathways and they are instrumental for understanding the physiological regulation of nutrient sensing by endogenous VIP at the maternal-foetal interface.

Vasoactive intestinal peptide alleviates food allergy via restoring regulatory B cell functions.

The immune regulatory cell dysfunction is associated with many immune diseases including food allergy (FA). This study aims to investigate the role of vasoactive intestinal peptide (VIP) in the maintenance of regulatory B cell (Br cell)'s immune suppressive functions by stabilizing thrombospondin (TSP1) expression. In this study, blood samples were collected from patients with food allergy (FA) and healthy control (HC) subjects. Br cells were isolated from the samples through flow cytometry cell sorting and analyzed by immunological approaches to determine the immune regulatory capacity. We found that the immune suppressive functions of Br cells were impaired in FA patients. The serum VIP levels were associated with the production of immune suppressive function-related mediators (interleukin-10, IL-10) of Br cells in FA patients. VIP counteracted IL-10 mRNA decay in Br cells by up regulating the TSP1 expression. TSP1 inhibited tristetraprolin (TTP) to prevent IL-10 mRNA decay in Br cells. Administration of VIP inhibited FA response through restoration of immune suppressive functions in Br cells. In conclusion, administration of VIP can alleviate FA response through up regulating expression of TSP1 to stabilize IL-10 expression in FA Br cells and recover the immune regulatory functions. The results have translational potential for the treatment of FA and other disorders associated with immune regulatory dysfunction of Br cells.

Therapeutic effect of vasoactive intestinal peptide on form-deprived amblyopic kittens

BackgroundExploring the role of vasoactive intestinal peptide (VIP) in the lateral geniculate body (LGBd) in visual development and studying the therapeutic effect of VIP on amblyopic kittens.MethodsThree-week-old domestic cats were divided into a control group (n = 10) and a monocular deprivation group (n = 20), with an eye mask covering the right eye of those in the deprived group. After pattern visual evoked potential (PVEP) recording confirmed the formation of monocular amblyopia, the left LGBd was isolated from 5 kittens in each group. The remaining control kittens continued to be raised, and the remaining deprivation group was divided into a VIP intervention group (n = 5), Sefsol (caprylic acid monoglyceride, VIP solution) intervention group (n = 5) and amblyopia non-intervention group (n = 5) after removal of the eye mask. Three weeks later, PVEPs, VIP immunohistochemistry and VIP mRNA expression in the left LGBd were compared across groups.ResultsAt 6 weeks of age, there were significant differences in P100 wave latency and amplitude and VIP immunohistochemistry and in situ hybridization between the control group and the deprivation group (P < 0.05). After 3 weeks of the corresponding interventions, the latency and amplitude in the VIP intervention group were better than that in the Sefsol intervention group and amblyopia non-intervention group (P < 0.05). Furthermore, VIP treatment increased the number of immunohistochemical VIP-positive cells (P < 0.05) and the average optical density of positive cells (P > 0.05), as well as the number (P < 0.05) and average optical density of VIP mRNA-positive cells (P < 0.05).ConclusionsVIP plays an important role in visual development. Nasal administration of VIP can improve the function of neurons in the LGBd of kittens and has a certain therapeutic effect on amblyopia.

Abstract 1205: Targeting vasoactive intestinal peptide signaling to enhance pancreatic cancer responsiveness to immunotherapy

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer related death in the U.S., outranking breast and colorectal cancer by 2030. Being completely refractory to checkpoint therapies, management of PDAC remains an unmet clinical need. Intriguingly, the cancer genome atlas shows elevated mRNA expression of vasoactive intestinal peptide (VIP), a neurotransmitter in exocrine pancreatic cancers. Interestingly, VIP also has immunosuppressive properties leading to decreased T cell proliferation and enhances expansion of myeloid derived suppressor cells (MDSCs) and regulatory T cells (Tregs). Thus, we are investigating the role of VIP in PDAC progression and the effect of inhibiting VIP signaling for improved responsiveness to immunotherapy. Methods: Level of secreted VIP in 1) serum of healthy volunteers, 2) untreated PDAC patients, 3) cell culture supernatant from murine melanoma, breast and PDAC cells and 4) serum from mice bearing these cell lines were tested via VIP specific enzyme immunoassay. Effect of inhibiting VIP signaling in-vivo was tested using VIPhyb, an antagonist for VIP receptor. Mice were subcutaneously inoculated with MT5 or luciferase transfected KPC (KPC luc), PDAC cell lines and treated with VIPhyb and/or anti-PD1 treatment after the tumors were palpable. The treatment regimen involved administering 10µg VIPhyb subcutaneously, every day and 200µg anti-PD1 or IgG2a, intraperitoneally, every three days, for 10 days. The tumors were measured using calipers or imaged via IVIS imaging system. The mice were sacrificed when tumors ulcerated or when they reached IACUC endpoint. Immunohistochemistry was performed on tumor tissue sections harvested at the time of sacrifice for expression of VIP, CD8 and DAPI. Results: Consistent with the human genome atlas, cell culture supernatants collected from murine PDAC cell lines had significantly higher levels of VIP as compared to melanoma and breast cancer cells. Similarly, elevated levels of VIP were observed in mice bearing PDAC tumors, and in plasma from untreated human PDAC patients, when compared to naïve mice and healthy volunteer samples, respectively. Treatment of immune competent mice bearing MT5 or KPC luc PDAC cells with the combination of VIPhyb and anti-PD1 produced complete and durable regression of tumors in 20% of the mice and delayed tumor progression in both tumor models. Further, upon analysis of the tumor tissues sections, significant infiltration of CD8+ T cells was observed in mice treated with the combination of VIPhyb and anti-PD1. Conclusion: VIP is a novel immune checkpoint pathway in PDAC. Blocking VIP signaling during anti-PD1 therapy, shows improved survival and delayed tumor progression in mouse models of PDAC. Experiments are underway to understand the mechanism of action, as well as, improving the potency of VIPhyb for enhanced clinical outcome. Citation Format: Sruthi Ravindranathan, Yiwen Li, Shuhua Wang, Mohammad Y. Zaidi, Gregory B. Lesinski, Bassel El-Rayes, Edmund K. Waller. Targeting vasoactive intestinal peptide signaling to enhance pancreatic cancer responsiveness to immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1205.

Vasoactive intestinal peptide induces proliferation of human hepatocytes.

Proliferation of hepatocytes in vitro can be stimulated by growth factors such as epidermal growth factor (EGF), but the role of vasoactive intestinal peptide (VIP) remains unclear. We have investigated the effect of VIP on maintenance and proliferation of human hepatocytes. Human hepatocytes were isolated from liver specimens obtained from patients undergoing liver surgery. Treatment with VIP or EGF was started 24h after plating and continued for 3 or 5d. DNA replication was investigated by Bromodeoxyuridine (BrdU) incorporation and cell viability detected by MTT assay. Cell lysate was analysed by western blotting and RT-PCR. Urea and albumin secretion into the culture supernatants were measured. VIP increased DNA replication in hepatocytes in a dose-dependant manner, with a peak response at day 3 of treatment. VIP treatment was associated with an increase in mRNA expression of antigen identified by monoclonal antibody Ki-67 (MKI-67) and Histone Cluster 3 (H3) genes. Western blotting analysis showed that VIP can induce a PKA/B-Raf dependant phosphorylation of extracellular signal-regulated kinases (ERK). Although EGF can maintain hepatocyte functions up to day 5, no marked efffect was found with VIP. VIP induces proliferation of human hepatocytes with little or no effect on hepatocyte differentiation. Further investigation of the role of VIP is required to determine if it may ultimately support therapeutic approaches of liver disease.

Role of vasoactive intestinal peptide in Aspergillus fumigatus-infected cornea.

To investigate the anti-inflammatory role of vasoactive intestinal peptide (VIP) in Aspergillus fumigatus (A. fumigatus) ketatitis. Expression of VIP was tested by polymerase chain reaction (PCR) in C57BL/6 and BALB/c normal and A. fumigatus infected corneas. C57BL/6 mice were pretreated with recombinant (r) VIP, while BALB/c mice were pretreated with VIP antagonist, and then infected with A. fumigatus. Clinical score was recorded. Expression of pro- and anti-inflammatory cytokines, toll-like receptor 4 (TLR4), lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1), and neutrophil infiltration were tested by PCR, enzyme-linked immunosorbent assay (ELISA), and myeloperoxidase (MPO) assay. VIP mRNA expression in BALB/c cornea was higher than C57BL/6 cornea at 1 and 3d post infection (p.i.). rVIP treatment of C57BL/6 mice showed alleviated disease and down-regulated expression of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), while IL-10 expression was up-regulated. Neutrophil infiltration and TLR4, IL-17 expression were decreased after rVIP treatment, while LOX-1 expression was up-regulated in C57BL/6. VIP antagonist pretreatment showed increased disease and higher IL-1β, TNF-α, TLR4, IL-17 and MPO levels, while IL-10 and LOX-1 levels were down-regulated in BALB/c mice. rVIP alleviate disease response of C57BL/6 mice. VIP antagonist resulted in worsened disease of BALB/c mice. VIP proposed anti-inflammatory role in A. fumigatus keratitis.

Role of vasoactive intestinal peptide during the transition from incubation behavior to rearing behavior in the female native Thai chicken

It is well documented that vasoactive intestinal peptide (VIP) is an avian prolactin-releasing factor, regulating the reproductive cycle, that initiates and maintains incubation behavior in avian species. Native Thai chicken has strong maternal behaviors. Thus, it is an excellent animal model to study this phenomenon. Changes in the numbers of VIP neurons within the nucleus inferioris hypothalami (IH) and nucleus infundibuli hypothalami (IN) are associated with maternal behaviors in the native Thai chicken. The objective of this study was to elucidate the role of VIP during the transition from egg incubation to rearing behavior in this species. The distributions of VIP-immunoreactive (-ir) neurons and fibers within the nucleus septalis lateralis (SL), nucleus anterior medialis hypothalami (AM), regio lateralis hypothalami (LHy), nucleus commissurae pallii (nCPa), nucleus ventromedialis hypothalami (VMN), and IH-IN were compared between incubating (INC) hens and replaced-egg-with-chicks (REC) hens, in which eggs were replaced by 3-day-old chicks after 6, 10, and 14 d of incubation period for 3 days. Using an immunohistochemistry technique, the results revealed that VIP-ir neurons and fibers were found within the SL, AM, LHy, nCPa, VMN, and IH-IN, with the greatest expression observed in the IH-IN in both groups. The number of VIP-ir neurons in the IH-IN was markedly decreased (P <0.05) in the REC hens when compared with those of the INC hens at 3 different time points (at d 9, 13, and 17). However, changes in the number of VIP-ir neurons between the INC and REC hens were not observed within other hypothalamic areas tested. These findings indicate that the presence of eggs and chicks affects the VIPergic system, and VIP neurons in the IH-IN might play a role in the transition from incubating to rearing behavior in the native Thai chicken.

Role of Vasoactive Intestinal Peptide in Promoting the Pathogenesis of Eosinophilic Esophagitis (EoE).

Role of Vasoactive Intestinal Peptide in Promoting the Pathogenesis of Eosinophilic Esophagitis (EoE).