Luciana Souza-Moreira

Adipose-derived mesenchymal stromal cells induce immunomodulatory macrophages which protect from experimental colitis and sepsis

Objective To investigate the effect of adipose-derived mesenchymal stromal cells (ASCs) on the activation state of macrophages (MΦ) in vitro, and the potential therapeutic effect of these cells in experimental colitis and sepsis. Design Murine bone marrow-derived macrophages were cultured with ASCs or with ASC conditioned media (ASC-MΦ) and characterised for the expression of several regulatory macrophage markers, including enzymes and cytokines, and for their immunomodulatory capacity in vitro. The therapeutic effect was investigated of ASC-MΦ in two models of experimental inflammatory colitis induced by trinitrobenzene sulphonic acid and dextran sodium sulphate, and in polymicrobial sepsis induced by caecal ligation and puncture. Results ASC-MΦ showed a phenotype that clearly differed from the classically activated macrophages or the alternatively activated macrophages induced by interleukin (IL)-4, characterised by high arginase activity, increased production of IL-10 upon restimulation and potent immunosuppressive activity on T cells and macrophages. Activation of cyclo-oxygenase-2 on ASCs seems to be critically involved in inducing this phenotype. Systemic infusion of ASC-MΦ inhibited colitis in mice, reducing mortality and weight loss while lowering the colonic and systemic levels of inflammatory cytokines. Importantly, therapeutic injection of ASC-MΦ in established chronic colitis alleviated its progression and avoided disease recurrence. Moreover, ASC-MΦ protected from severe sepsis by reducing the infiltration of inflammatory cells into various organs and by downregulating the production of several inflammatory mediators, where ASC-MΦ-derived IL-10 played a critical role. Conclusion ASCs induce a distinct regulatory activation state of macrophages which possess potent immunomodulatory ability and therapeutic potential in inflammatory bowel diseases and sepsis.

Neuropeptides as Pleiotropic Modulators of the Immune Response

Although necessary to eliminate pathogens, inflammation can lead to serious deleterious effects in the host if left unchecked. During the inflammatory response, further damage may arise from potential autoimmune responses occurring when the immune cells and molecules that respond to pathogen-derived antigens also react to self-antigens. In this sense, the identification of endogenous factors that control exacerbated immune responses is a key goal for the development of new therapeutic approaches for inflammatory and autoimmune diseases. Some neuropeptides that are produced during the ongoing inflammatory response have emerged as endogenous anti-inflammatory agents that could collaborate in tuning the balanced steady state of the immune system. These neuropeptides participate in maintaining immune tolerance through two distinct mechanisms: by regulating the balance between pro-inflammatory and anti-inflammatory factors, and by inducing the emergence of regulatory T cells with suppressive activity against autoreactive T cell effectors. Indeed, a functioning neuropeptide system contributes to general health, and alterations in the levels of these neuropeptides and/or their receptors lead to changes in susceptibility to inflammatory and autoimmune diseases. Recently, we found that some neuropeptides also have antimicrobial and antiparasitic actions, suggesting that they could act as primary mediators of innate defense, even in the most primitive organisms. In this review, we use the vasoactive intestinal peptide as example of an immunomodulatory neuropeptide to summarize the most relevant data found for other neuropeptides with similar characteristics, including adrenomedullin, urocortin, cortistatin and ghrelin.

Therapeutic Effect of Human Amniotic Membrane–Derived Cells on Experimental Arthritis and Other Inflammatory Disorders

Rheumatoid arthritis (RA) is an autoimmune disease caused by loss of immunologic self tolerance and characterized by chronic joint inflammation. Cells isolated from human amniotic membrane (HAMCs) were recently found to display immunosuppressive properties. The aim of this study was to characterize the effect of HAMCs on antigen‐specific T cell responses in RA patients and to evaluate their therapeutic potential in a preclinical experimental model of RA.

Analgesic effect of the neuropeptide cortistatin in murine models of arthritic inflammatory pain

OBJECTIVE To investigate the role of the antiinflammatory neuropeptide cortistatin in chronic pain evoked by joint inflammation. METHODS Thermal and mechanical hyperalgesia was evoked in mouse knee joints by intraplantar injection of tumor necrosis factor α and intraarticular infusion of Freunds complete adjuvant, and the analgesic effects of cortistatin, administered centrally, peripherally, and systemically, were assessed. In addition, the effects of cortistatin on the production of nociceptive peptides and the activation of pain signaling were assayed in dorsal root ganglion cultures and in inflammatory pain models. The role of endogenous cortistatin in pain sensitization and perpetuation of chronic inflammatory states was evaluated in cortistatin-deficient mice. Finally, the effect of noxious/inflammatory stimuli in the production of cortistatin by the peripheral nociceptive system was assayed in vitro and in vivo. RESULTS Expression of cortistatin was observed in peptidergic nociceptors of the peripheral nociceptive system, and endogenous cortistatin was found to participate in the tuning of pain sensitization, especially in pathologic inflammatory conditions. Results showed that cortistatin acted both peripherally and centrally to reduce the tactile allodynia and heat hyperalgesia evoked by arthritis and peripheral tissue inflammation in mice, via mechanisms that were independent of its antiinflammatory action. These mechanisms involved direct action on nociceptive neurons and regulation of central sensitization. The analgesic effects of cortistatin in murine arthritic pain were linked to binding of the neuropeptide to somatostatin and ghrelin receptors, activation of the G protein subunit Gαi , impairment of ERK signaling, and decreased production of calcitonin gene-related peptide in primary nociceptors. CONCLUSION These findings indicate that cortistatin is an antiinflammatory factor with potent analgesic effects that may offer a new approach to pain therapy in pathologic inflammatory states, including osteoarthritis and rheumatoid arthritis.

Therapeutic effect of ghrelin in experimental autoimmune encephalomyelitis by inhibiting antigen-specific Th1/Th17 responses and inducing regulatory T cells

Ghrelin is an important gastrointestinal hormone that regulates feeding and metabolism. Moreover, ghrelin is produced by immune cells and shows potent anti-inflammatory activities. Here, we investigated its effect in two models of experimental autoimmune encephalomyelitis (EAE) that mirror chronic and relapsing-remitting multiple sclerosis. A short systemic treatment with ghrelin after the disease onset reduced clinical severity and incidence of both forms of EAE, which was associated with a decrease in inflammatory infiltrates in spinal cord and in the subsequent demyelination. This therapeutic effect was exerted through the reduction of the autoimmune and inflammatory components of the disease. Ghrelin decreased the presence/activation of encephalitogenic Th1 and Th17 cells in periphery and nervous system, down-regulated various inflammatory mediators, and induced regulatory T cells. In summary, our findings provide a powerful rationale for the assessment of the efficacy of ghrelin as a novel therapeutic approach for treating multiple sclerosis through distinct immunomodulatory mechanisms and further support the concept that the neuroendocrine and immune systems crosstalk to finely tune the final immune response of our body.

Paradoxical Effect of Cortistatin Treatment and Its Deficiency on Experimental Autoimmune Encephalomyelitis

Cortistatin is a cyclic-neuropeptide produced by brain cortex and immune cells that shows potent anti-inflammatory activity. In this article, we investigated the effect of cortistatin in two models of experimental autoimmune encephalomyelitis (EAE) that mirror chronic and relapsing-remitting multiple sclerosis. A short-term systemic treatment with cortistatin reduced clinical severity and incidence of EAE, the appearance of inflammatory infiltrates in spinal cord, and the subsequent demyelination and axonal damage. This effect was associated with a reduction of the two deleterious components of the disease, namely, the autoimmune and inflammatory response. Cortistatin decreased the presence/activation of encephalitogenic Th1 and Th17 cells in periphery and nervous system, and downregulated various inflammatory mediators, whereas it increased the number of regulatory T cells with suppressive effects on the encephalitogenic response. Moreover, cortistatin regulated glial activity and favored an active program of neuroprotection/regeneration. We further used cortistatin-deficient mice to investigate the role of endogenous cortistatin in the control of immune responses. Surprisingly, cortistatin-deficient mice were partially resistant to EAE and other inflammatory disorders, despite showing competent inflammatory/autoreactive responses. This unexpected phenotype was associated with elevated circulating glucocorticoids and an anxiety-like behavior. Our findings provide a powerful rationale for the assessment of the efficacy of cortistatin as a novel multimodal therapeutic approach to treat multiple sclerosis and identify cortistatin as a key endogenous component of neuroimmune system.

Neuropeptides as Therapeutic Approach to Autoimmune Diseases

Because there are no particular molecular signatures of self, autoimmunity is the inevitable evolutionary price of being able to make effective responses against a wide variety of pathogens by the immune system. Without the various phenomena referred to as immune tolerance, the organism would surely self-destruct. Considerable evidence suggests that various endogenous neuropeptides play a major role in the education of our immune system to be self-tolerant. The fact that neuropeptides regulate various layers involved in maintenance of tolerance, including regulation of the balance between pro-inflammatory and anti-inflammatory responses and between self-reactive Th1/Th17 cells and regulatory T cells, makes them attractive candidates for the development of new therapies for the treatment of autoimmune disorders. Here we use the vasoactive intestinal peptide of a prototype of immunomodulatory neuropeptide to review the most relevant data found for other neuropeptides with similar characteristics, including melanocyte-stimulating hormone, urocortin, adrenomedullin, neuropeptide Y, cortistatin and ghrelin. We also evaluate the challenges that must be overcome before achieving their clinical application and offer our opinion on how a physiologically functional neuropeptide system contributes to general health.

Adrenomedullin protects from experimental autoimmune encephalomyelitis at multiple levels

Adrenomedullin is a neuropeptide known for its cardiovascular activities and anti-inflammatory effects. Here, we investigated the effect of adrenomedullin in a model of experimental autoimmune encephalomyelitis (EAE) that mirrors chronic progressive multiple sclerosis. A short-term systemic treatment with adrenomedullin reduced clinical severity and incidence of EAE, the appearance of inflammatory infiltrates in spinal cord and the subsequent demyelination and axonal damage. This effect was exerted at multiple levels affecting both early and late events of the disease. Adrenomedullin decreased the presence/activation of encephalitogenic Th1 and Th17 cells and down-regulated several inflammatory mediators in peripheral lymphoid organs and central nervous system. Noteworthy, adrenomedullin inhibited the production by encephalitogenic cells of osteopontin and of Granulocyte Macrophage Colony-Stimulating Factor (GM-CSF), two critical cytokines in the development of EAE. At the same time, adrenomedullin increased the number of IL-10-producing regulatory T cells with suppressive effects on the progression of EAE. Furthermore, adrenomedullin generated dendritic cells with a semi-mature phenotype that impaired encephalitogenic responses in vitro and in vivo. Finally, adrenomedullin regulated glial activity and favored an active program of neuroprotection/regeneration. Therefore, the use of adrenomedullin emerges as a novel multimodal therapeutic approach to treat chronic progressive multiple sclerosis.

Cortistatin reduces atherosclerosis in hyperlipidemic ApoE-deficient mice and the formation of foam cells

Atherosclerosis is a chronic inflammatory cardiovascular disease that is responsible of high mortality worldwide. Evidence indicates that maladaptive autoimmune responses in the arterial wall play critical roles in the process of atherosclerosis. Cortistatin is a neuropeptide expressed in the vascular system and atherosclerotic plaques that regulates vascular calcification and neointimal formation, and inhibits inflammation in different experimental models of autoimmune diseases. Its role in inflammatory cardiovascular disorders is largely unexplored. The aim of this study is to investigate the potential therapeutic effects of cortistatin in two well-established preclinical models of atherosclerosis, and the molecular and cellular mechanisms involved. Systemic treatment with cortistatin reduced the number and size of atherosclerotic plaques in carotid artery, heart, aortic arch and aorta in acute and chronic atherosclerosis induced in apolipoprotein E-deficient mice fed a high-lipid diet. This effect was exerted at multiple levels. Cortistatin reduced Th1/Th17-driven inflammatory responses and increased regulatory T cells in atherosclerotic arteries and lymphoid organs. Moreover, cortistatin reduced the capacity of endothelial cells to bind and recruit immune cells to the plaque and impaired the formation of foam cells by enhancing cholesterol efflux from macrophages. Cortistatin emerges as a new candidate for the treatment of the clinical manifestations of atherosclerosis.

Lulling immunity, pain, and stress to sleep with cortistatin.

Cortistatin is a neuropeptide isolated from cortical brain regions, showing high structural homology and sharing many functions with somatostatin. However, cortistatin exerts unique functions in the central nervous and immune systems, including decreasing locomotor activity, inducing sleep‐promoting effects, and deactivating inflammatory and T helper (TH)1/TH17–driven responses in preclinical models of sepsis, arthritis, multiple sclerosis, and colitis. Besides its release by cortical and hippocampal interneurons, cortistatin is produced by macrophages, lymphocytes, and peripheral nociceptive neurons in response to inflammatory stimuli, supporting a physiological role of cortistatin in the immune and nociceptive systems. Cortistatin‐deficient mice have been shown to have exacerbated nociceptive responses to neuropathic and inflammatory pain sensitization. However, a paradoxical effect has been observed in studies of immune disorders, in which, despite showing competent inflammatory/autoreactive responses, cortistatin‐deficient mice were partially resistant to systemic autoimmunity and inflammation. This unexpected phenotype was associated with elevated circulating glucocorticoids and anxiety‐like behavior. These findings support cortistatin as a novel multimodal therapeutic approach to treat autoimmunity and clinical pain and identify it as a key endogenous component of the neuroimmune system related to stress responses.