vasoactive-intestinal-peptide and Lupus-Erythematosus--Systemic

Neuropsychiatric systemic lupus erythematosus (NPSLE) is one of the most common and severe manifestations of lupus; however, its pathogenesis is still poorly understood. While there is sparse evidence suggesting that the ongoing autoimmunity may trigger pathogenic changes to the central nervous system (CNS) microvasculature, culminating in inflammatory/ischemic damage, further evidence is still needed. In this study, we used the spontaneous mouse model of SLE (NZBWF1 mice) to investigate the expression of genes and proteins associated with endothelial (dys)function: tissue and urokinase plasminogen activators (tPA and uPA), intercellular and vascular adhesion molecules 1 (ICAM-1 and VCAM-1), brain derived neurotrophic factor (BDNF), endothelial nitric oxide synthase (eNOS) and Krüppel-like factor 4 (KLF4) and neuroprotection/immune modulation: pituitary adenylate cyclase-activating peptide (PACAP), vasoactive intestinal peptide (VIP), PACAP receptor (PAC1), VIP receptors 1 and 2 (VPAC1 and VPAC2). Analyses were carried out both in the hippocampus and striatum of SLE mice of two different age groups (2 and 7 months old), since age correlates with disease severity. In the hippocampus, we identified a gene/protein expression profile indicative of mild endothelial dysfunction, which increased in severity in aged SLE mice. These alterations were paralleled by moderate alterations in the expression of VIP, PACAP and related receptors. In contrast, we report a robust upregulation of endothelial activation markers in the striatum of both young and aged mice, concurrent with significant induction of the VIP/PACAP system. These data identify molecular signatures of endothelial alterations in the hippocampus and striatum of NZBWF1 mice, which are accompanied by a heightened expression of endogenous protective/immune-modulatory neuropeptides. Collectively, our results support the idea that NPSLE may cause alterations of the CNS micro-vascular compartment that cannot be effectively counteracted by the endogenous activity of the neuropeptides PACAP and VIP.

Topics: Animals; Lupus Erythematosus, Systemic; Mice; Pituitary Adenylate Cyclase-Activating Polypeptide; Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; Receptors, Vasoactive Intestinal Peptide, Type II; Receptors, Vasoactive Intestinal Polypeptide, Type I; Vasoactive Intestinal Peptide

Cardiovascular autonomic neuropathy (CAN) in patients with rheumatic diseases may result in sudden death, possibly from arrhythmia and myocardial infarction due to its frequent association with microvascular disease. Autonomic dysfunction may contribute to initiation and perpetuation of rheumatic diseases. Thus, we aimed to assess cardiovascular autonomic function in lupus and juvenile idiopathic arthritis (JIA) patients.. Assessment of cardiovascular autonomic function was done in 20 lupus and 20 JIA patients, aged 8-16 years, by five non-invasive autonomic function tests (AFTs) and serum levels of neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP), as indicators of sympathetic and parasympathetic functions, respectively, in comparison with 40 matched healthy control subjects.. Clinical evidence of CAN was found in 65 and 40% of lupus and JIA patients, respectively, and in none of healthy controls. Lupus and JIA patients had significantly lower serum NPY and VIP than controls (P < 0.001). The five AFTs score had significant negative correlations to NPY and VIP (P < 0.001). Patients with CAN had significantly lower serum NPY and VIP than patients without (P < 0.001). Clinical evidence of CAN was found in 41.7 and 14.3% of asymptomatic lupus and JIA patients, respectively. There was significant positive association between CAN and important disease manifestations, including activity, in these patients.. CAN is common in lupus and JIA patients, even in absence of relevant symptoms. Thus, assessments of cardiac autonomic function, by AFTs and serum autonomic neuropeptides (NPY and VIP), and the therapeutic effects of NPY and VIP are recommended in these patients.

Topics: Adolescent; Arthritis, Juvenile; Autonomic Nervous System; Blood Pressure; Cardiovascular System; Case-Control Studies; Child; Cross-Sectional Studies; Egypt; Female; Heart Rate; Humans; Logistic Models; Lupus Erythematosus, Systemic; Male; Neuropeptide Y; Neuropeptides; Posture; Rheumatic Diseases; Vasoactive Intestinal Peptide

The immunoregulatory neuropeptide vasoactive intestinal peptide (VIP) was cleaved by purified IgG from Fas-defective C3H/gld mice, lupus patients, and autoimmune thyroiditis patients. No VIPase activity was detected in IgG from control mice and humans. Kinetic analyses of VIPase IgG preparations suggested low-affinity recognition of VIP. Yet the VIPase activity was VIP selective, judged by lack of correlation with other protease activities expressed by the IgG and by noninterference of unrelated peptides in the activity. Recombinant Fv constructs selected from a human lupus phage show library displayed VIPase activity, confirming that the active site is located in the V domains. Inhibition of the VIPase activity by di-isopropylfluorophosphate suggested a serine protease-like mechanism of catalysis. Irreversible binding of a biotinyated phosphonate diester by the IgG and Fv preparations was observed, consistent with the presence of activated nucleophiles similar to those in enzymes capable of covalent catalysis. These observations show that VIP is a target for specific catalytic autoantibodies in autoimmune disease.

Topics: Animals; Autoantibodies; Autoimmune Diseases; Catalysis; Cloning, Molecular; fas Receptor; Humans; Hydrolysis; Immunoglobulin Fragments; Immunoglobulin G; Lupus Erythematosus, Systemic; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Molecular Sequence Data; Mutation; Oligopeptides; Thyroglobulin; Thyroiditis, Autoimmune; Vasoactive Intestinal Peptide

Autoantibodies capable of binding the immunoregulatory neuropeptide vasoactive intestinal peptide (VIP) were detected in the sera of a mouse strain prone to autoimmune disease due to the lpr mutation (MRL/lpr). The autoantibodies were not present in control wildtype MRL/lpr mice, but they were readily detected in humans without autoimmune disease. The binding was due to low affinity VIP recognition. Increased VIP binding activity was evident in patients with systemic lupus erythematosus but not systemic sclerosis, Sjögren's syndrome (SS), rheumatoid arthritis or autoimmune thyroiditis. Recombinant VIP binding Fv clones (fragment variable; the variable domains of the light and heavy chains antibody subunits joined with a peptide linker) were isolated from a phage display library prepared from lupus patients. One Fv clone displaying VIP-selective binding and several clones displaying cross-reactivity with unrelated peptides were identified. Replacement mutations in the VIP-selective clone were preferentially localized in the regions known to make contacts with the antigen, i.e. the complementarity determining regions, suggesting that the selective binding activity is due to immunological maturation of the antibodies. Frequent occurrences of autoantibody responses to VIP indicate that immunological tolerance to this neuropeptide can be readily broken. The depletion of VIP by specific antibodies in autoimmune disease may interfere with VIP regulation of T cells and inflammatory cells and result in further amplification of autoreactive immunological responses.

Topics: Animals; Autoantibodies; Autoimmunity; Enzyme-Linked Immunosorbent Assay; Humans; Immunoglobulin Fragments; Lupus Erythematosus, Systemic; Mice; Radioimmunoassay; Scleroderma, Systemic; Vasoactive Intestinal Peptide

It has been reported that more than 50% of lupus patients show various forms of neurological deficits including impaired cognitive functions and psychiatric disorders. Using an animal model of lupus we investigated the production of neuropeptides in the brain of NZB/W F1 female hybrid mice and its parental strain NZB and NZW. Our results indicate that the alteration in learning and memory described in lupus mice are paralleled by a decrease in calcitonin gene-related peptide, substance P and neuropeptide Y (NPY) levels in the hippocampus and a significant decrease of NPY in the cortex. These findings are interesting in the light of previously reported results suggesting that these neuropeptides can play an important role in cognitive functions. We also observed a decrease of NPY and vasoactive intestinal polypeptide levels in the hypothalamus of lupus prone mice and these changes may be related to the disregulation of the hypothalamus-pituitary-adrenal axis observed in lupus prone mice.

Topics: Animals; Brain; Calcitonin Gene-Related Peptide; Cerebral Cortex; Female; Hippocampus; Hypothalamus; Lupus Erythematosus, Systemic; Mice; Neuropeptide Y; Neuropeptides; Substance P; Vasoactive Intestinal Peptide

In the present study we used a well-characterised model of murine lupus, the female NZB/W hybrid, to study the possible involvement of neuropeptides in the pathogenesis of systemic lupus erythematosus (SLE). Analysis of neuropeptides with a possible role in inflammation showed that substance P (SP) calcitonin gene-related peptide (CGRP) and neuropeptide Y (NPY) are present in increased quantities in the inflamed kidneys of SLE mice, confirming their involvement in local inflammation, while there is a general reduction in the peptide concentrations in the lymphoid organs of lupus mice, except for NPY. Our results suggest that the altered neuropeptide concentrations observed in the SLE lymphoid organs may be partly responsible for the altered immune response and contribute to the development of autoimmune diseases.

Topics: Animals; Calcitonin Gene-Related Peptide; Female; Kidney; Lupus Erythematosus, Systemic; Mice; Neuroimmunomodulation; Neuropeptide Y; Neuropeptides; Spleen; Substance P; Thymus Gland; Vasoactive Intestinal Peptide