Journal - Immunopharmacology and immunotoxicology (United States )

Abstract :

Host-parasite interactions and their outcome constitute a critical and challenging step in disease establishment in cutaneous leishmaniasis. In the present in vitro study we investigated the possible modulating effects of both sensory and autonomic neuropeptides that normally exist in human and mouse skin, on the uptake and leishmanicidal capacity of macrophages on Leishmania (L.) major parasites, using a monocyte/macrophage murine cell line (Raw 264.7). The sensory neuropeptides somatostatin (SOM), calcitonin gene-related peptide (CGRP) and substance P (SP) suppressed the macrophage capacity for phagocytosing L. major promastigotes at different concentrations, 10(-10) - 10(-5) M, however, the suppressive effect of SP does not reach a significant level. CGRP and SP enhanced the leishmanicidal capacity of macrophages at 10(-7) M, and 10(-5) M, respectively, whereas SOM was without effect. The autonomic neuropeptides vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY) both suppressed the phagocytic and leishmanicidal capacities of macrophages at various concentrations, 10(-10) - 10(-5) M. The findings indicate that neuropeptides have modulating effects on macrophage-L. major interactions. These effects might be exerted by a direct action on macrophages or indirectly through induction of other mediators.

Journal - Neuroscience letters (IRELAND )

Abstract :

The expression of the sensory neuropeptide calcitonin gene-related peptide (CGRP) in the skin, secondary lymphoid organs and dorsal root ganglia (L4-L6) in Leishmania major-induced inflammation was evaluated by radioimmunoassay. The investigation was conducted on two mouse strains, the susceptible BALB/c and the resistant C57BL/6. The CGRP concentration in the inflamed skin of both mouse strains was decreased as early as 1 week postinfection, compared to controls. A further reduction was observed in both mouse strains throughout the 9-week study period, but was more evident in the susceptible strain. The CGRP concentration was increased in the ipsilateral dorsal root ganglia (L4-L6) of mice of the resistant strain 1 week postinfection, while no change was observed in the susceptible strain. In the remaining part of the study period there was a reduction in CGRP in the ipsilateral dorsal root ganglia of both mouse strains. In the spleen, a reduction was noted in the infected BALB/c at all measurement times (significant at 6 and 9 weeks), while no change was observed in C57BL/6 strain. These findings may indicate a regulatory function of CGRP in the pathophysiology of murine cutaneous leishmaniasis and hence in the disease outcome. The reduction in CGRP might also explain the defective nociception observed in patients with cutaneous leishmaniasis.

Journal - Neuroreport (ENGLAND )

Abstract :

Neuropeptide Y (NPY) concentrations were investigated by radioimmunoassay and immunohistochemistry in a murine model of cutaneous leishmaniasis, using a susceptible (BALB/c) and a resistant (C57BL/6) mouse strain. The analyses were performed on the skin, secondary lymphoid organs and dorsal root ganglia (DRG) at 1, 3, 6 and 9 weeks postinfection. An overall reduction in the NPY concentrations in the studied organs was observed in both mouse strains; the reduction in the skin and draining lymph nodes was more evident and progressive in the susceptible strain. Using immunohistochemistry there seemed to be a reduction in NPY immunoreactivity in all inflamed tissues analysed compared to the controls. These observations might indicate a possible pathophysiological role for NPY in murine cutaneous leishmaniasis.

Journal - Immunopharmacology and immunotoxicology (UNITED STATES )

Abstract :

The intimate, bidirectional link between neuroendocrine and immune systems is now accepted. A modulating effect of the nervous system on immune and inflammatory responses has been corroborated by identification of neuropeptide receptors on immunocompetent cells and the finding that neuropeptides can regulate leukocyte functions. The present study was undertaken to investigate the possible immunomodulatory role of sensory (SOM, CGRP and SP) and autonomic (VIP and NPY) neuropeptides in a murine model of cutaneous leishmaniasis, using two genetically different inbred mouse strains, BALB/c and C57BL/6, respectively susceptible and resistant to Leishmania (L.) major infection. The parameters studied were extent of splenocyte proliferation, as measured by thymidine uptake, and the ability of these cells to secrete IFN-gamma and IL-4 by using a two-site ELISA, upon in vitro challenge with L. major parasites and addition of the neuropeptides. The resistant mouse splenocyte proliferation was enhanced by SOM, CGRP, and VIP at 10(-5), 10(-6) and 10(-9) M concentration, respectively, but was inhibited by NPY at 10(-5) M. Proliferation of the splenocytes from the susceptible strain was inhibited by SOM (10(-11) M) and CGRP(10(-5) M). Somatostatin, at various concentrations, stimulated IFN-gamma secretion in both mouse strain splenocytes, and IL-4 production in the susceptible mouse. Calcitonin gene-related peptide enhanced IFN-gamma secretion in susceptible mouse splenocytes at 10(-6), 10(-7) and 10(-9) M, as did VIP at 10(-10) M and NPY at 10(-7) M. Vasoactive intestinal peptide also stimulated IL-4 production in BALB/c splenocytes at all concentrations used. Substance P had no effect on either cell proliferation or cytokine secretion in either of the two mouse strains. These findings indicate that the nervous system, represented by sensory and autonomic nerve terminals and their content of neuromediators, may be involved in the pathophysiology of cutaneous leishmaniasis.

Journal - Acta dermato-venereologica (NORWAY )

Abstract :

The cross-talk between the immune and nervous systems is becoming an interesting field of research and there is accumulating evidence supporting this notion. In the present study we investigated the levels of nerve growth factor in a murine model of cutaneous leishmaniasis, using a two-site ELISA. Two strains of inbred mice were used for this purpose, namely BALB/c and C57BL/6, genetically susceptible and resistant, respectively, to infection with Leishmania major. This work demonstrates a difference in expression of nerve growth factor in the skin and secondary lymphoid organ microenvironment, as well as in the serum, between these mouse strains. The high nerve growth factor levels in the microenvironment seem to be important and possibly critical for the outcome of the disease. Compared with controls, the resistant strain, C57BL/6, expressed significantly increased nerve growth factor levels in the skin, secondary lymphoid organs and serum at 1 week post-infection, whereas the susceptible strain, BALB/c, showed no change in the skin and a slight increase in the lymphoid organs and serum at this time-point. These high nerve growth factor levels in the early stage of the disease, whether produced directly by the inflammatory cells or indirectly through its induction by other cytokines or both, might indicate a contribution of this neurotrophic factor to differentiation of naive T lymphocytes into either Th1 or Th2 subsets that fundamentally govern the disease outcome. The expression of significantly elevated nerve growth factor levels in the skin and lymphoid organs of C57BL/6 at the late studied time points might suggest a role for nerve growth factor in the resolution of the disease process, which is usually evident from 6 weeks post-infection in this model. The high nerve growth factor levels expressed in the skin, lymph nodes and serum of BALB/c at late stages of the disease may be explained as an attempt to counteract the progression and dissemination of the disease. This investigation adds further experimental evidence for an anti-inflammatory effect of nerve growth factor, possibly through its action as a link between the nervous and immune systems.

Journal - Scandinavian journal of immunology (ENGLAND )

Abstract :

Recruitment, migration and adherence of macrophages and their interaction with inoculated promastigotes are key steps in the initiation of the inflammatory process in cutaneous leishmaniasis. Parasite- and nervous system-derived factors might be involved in this process. In the present study the chemotactic activities of live, killed and sonicated Leishmania major promastigotes and of the promastigote culture supernatant as well as the L. major surface protease gp63 towards a murine macrophage cell line, Raw 264.7, were investigated, using the Boyden technique. The sensory neuropeptides SOM, CGRP and SP, and the autonomic neuropeptides VIP and NPY, were also investigated for possible modulatory effects on this chemotaxis, using the living promastigotes. Living promastigotes were the most efficient attractants for macrophages compared with other forms of the parasites. Prior incubation of the macrophages with the parasites completely abolished the chemotactic activity. This might indicate that the living promastigote chemotaxis is a receptor-mediated process. On the other hand, paraformaldehyde-killed promastigotes not only failed to induce macrophage chemotaxis but also inhibited it in comparison with the control. The surface protease gp63 tended to inhibit the macrophage chemotactic activity and the sonicate tended to stimulate it compared with controls. The culture supernatant had no effect, indicating that the chemoattractive factors putatively synthesized by the living promastigotes are not released to the surrounding medium. Somatostatin inhibited L. major promastigote-induced macrophage migration at a high concentration, 10(-6) M, while substance P inhibited it at both low concentrations, 10(-10) and 10(-9) M, and a high one, 10(-6) M, the last-mentioned having the greatest inhibitory effect. A stimulatory effect of calcitonin gene-related peptide was found at high concentrations, 10(-5) and 10(-6) M. Vasoactive intestinal peptide stimulated macrophage chemotactic activity at both a high, 10(-5) M, and at a low, 10(-9) M, concentration, the same concentration at which neuropeptide Y exerted its maximum inhibitory effect.

Journal - Experimental dermatology (DENMARK )

Abstract :

Paraformaldehyde-fixed biopsy specimens of normal and chronic cutaneous leishmaniasis human skin were investigated for the presence and cellular distribution of interleukin-1 alpha, interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha and the corresponding receptors in eccrine sweat glands, using an indirect immunoperoxidase technique. There was cytoplasmic staining for all 4 cytokines as well as their receptor proteins in the clear cells of the eccrine sweat glands of both normal and inflamed skin specimens. No staining could be seen in the dark cells or the myoepithelial cells, neither in normal nor in inflamed skin. However, a difference between normal and inflamed skin was observed in the ductal system. Thus, cell layers of the dermal ducts in leishmaniasis skin were stained for all 4 cytokines, with more intense labelling in the basal cell layer of the coiled ducts, while in the normal skin, an intense staining was more evident in the inner luminal layer, with variable and less intense labelling of the basal layer. The immunolabelling for the cytokine receptors within the dermal ducts exhibited similar staining intensity in both luminal and basal cell layers, except in the case of the IL-6 receptor, which showed a moderate to intense signal in the basal cell layer but a weak staining of the luminal cell layer. Infiltrating inflammatory cells around the sweat gland apparatus in leishmaniasis skin exhibited immunoreactivities for all cytokines and their corresponding receptors.

Journal - Acta dermato-venereologica (NORWAY )

Abstract :

Immunoreactivity to interleukin-1 alpha, interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha and their receptors, as well as the endogenous interleukin-1 receptor antagonist, was investigated in hair follicles in paraffin-embedded normal human skin. Interleukin-1 beta- and tumour necrosis factor-alpha-like immunoreactivities were found in the inner root sheath layer of hair follicles, at the suprapapillary level. Interleukin-1 receptor-like immunoreactivity was also found in this layer, while there was a variable immunoreactivity to the interleukin-1 receptor antagonist. In the outer root sheath there was a weak to moderate staining for the four cytokines, in addition to intense staining for their receptors and a weak staining for the antagonist. The fibrous root sheath had a moderate immunoreactivity for interleukin-1 alpha and interleukin-6. The distribution patterns suggest that these cytokines, particularly interleukin-1 beta and tumour necrosis factor-alpha, may have a protective role in hair formation, while all the investigated proinflammatory cytokines may have a role in the differentiation process.

Journal - Archives of dermatological research (GERMANY )

Journal - The American Journal of dermatopathology (UNITED STATES )

Abstract :

Interleukin-1 alpha and -1 beta, interleukin-6, and tumor necrosis factor-alpha may have a protective effect against malignant transformation of melanocytes. By using monoclonal and polyclonal antisera we investigated, in paraformaldehyde-fixed tissue, the cellular distribution of these cytokines in human common and dysplastic nevocellular nevi and in malignant melanoma. Generally, the immunolabeling for all of these cytokines was both cytoplasmic and perinuclear as well as present in the basement membrane, which surrounds the individual cells or cellular nests of some of the nevi. In compound and intradermal nevi the immunolabeling was abundant, although there was a variation in the staining intensity between individual cells and even inside a single nevus cell, ranging from weak to strong. There was a strong labeling of the basement membrane around the cellular nests and around individual cells inside or outside the nests in the papillary and reticular dermis. With regard to the common junctional and dysplastic nevi and malignant melanoma, occasional immunolabeling could be seen in some cells within the cellular nests in the junctional area or papillary dermis, ranging from faint to moderate in intensity, but in this case the basement membrane around individual cells or cellular nests was not stained. The staining of nevocellular nevi and malignant melanoma indicates the possibility of these cytokines being synthesized by the nevi and melanoma cells. The labeling of the basement membrane in compound and intradermal nevi suggests that cytokines produced by nevocellular cells may be stored in the basement membrane, from which they could be released upon environmental or mechanical challenge. This distribution pattern would support the hypothesis that these cytokines may protect the common nevi from malignant transformation.

Journal - Acta dermato-venereologica (NORWAY )

Abstract :

Paraformaldehyde-fixed tissue of chronic granulomatous skin conditions, such as cutaneous leishmaniasis, granuloma annulare, leprosy and hidroadenitis, was investigated for the presence of interleukin-1 alpha-, interleukin-1 beta-, interleukin-6- and tumour necrosis factor-alpha-like immunoreactivities among the cellular infiltrates. There was a weak to strong cytoplasmic labelling of plasma cells for interleukin-6 and tumour necrosis factor-alpha at the periphery of the granulomatous mass and around the skin appendages. The interleukin-6-like immunoreactivity seemed to be correlated with the coarseness of the chromatin material of the cells, being more intense with coarse chromatin. The cytoplasmic labelling for interleukin-1 alpha and interleukin-1 beta in the plasma cells was less intense. Epitheloid, Langhans' giant cells and small round cells exhibited a weak to moderate cytoplasmic labelling for interleukin-1 alpha and interleukin-1 beta, whereas the staining intensity for interleukin-6 and tumour necrosis factor-alpha was weak to strong. In addition, there was staining of the stroma in the centre of granuloma with antisera against interleukin-1 alpha, interleukin-1 beta, interleukin-6 and tumour necrosis factor-alpha. This area contained few cells, suggesting that the granuloma was in a resolution process. A contribution of interleukin-6 and tumour necrosis factor-alpha to the granulomatous reaction, at least during the maintenance period, is suggested by the occurrence of these cytokines in the skin conditions studied. The findings are also consistent with a suggested role of B cells in the late stages of the granulomatous reaction. In addition, they are in line with the reported declining role of interleukin-1 in the maintenance of granuloma.