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Nerve fiber repulsion by semaphorins – More redundancy than expected in the rheumatoid arthritis joint?
PNIRS meeting abstracts / Brain, Behavior, and Immunity 25 (2011) S179–S242
21. Nerve fiber repulsion by semaphorins – More redundancy than expected in the rheumatoid arthritis joint? S. Klatt, A. Fassold, R.H. Straub Department of Internal Medicine I, University Hospital of Regensburg, Germany Lab. of NeuroEndocrineImmunology and Rheumatology, Franz-JosefStrauss-Allee 11, Regensburg 93042, Germany Background/purpose: The loss of sympathetic nerve fibers (SNF) is a general principle in inflammatory diseases. Since sympathetic neurotransmitters exert antiinflammatory effects at increased concentrations, their loss is unfavorable in chronic inflammatory diseases like rheumatoid arthritis (RA). Semaphorins are the major factors which are involved in guidance and repulsion of nerve fibers. Recent findings also indicate increased concentrations of norepinephrine, dopamine and 17b-estradiol in synovial tissue of RA patients. The aim of this project was to test the effects of these substances on growth and repulsion of SNF in vitro. Methods: The behavior of SNF from sympathetic trunk ganglia of postnatal mice was investigated in a neurite outgrowth assay using time-lapse microscopy. Results: Semaphorins 3F and 3C induced a nearly complete repulsion of SNF up to 100%. TNF repelled nerve fibers with variable effects (10–100%). High concentrations of catecholamines (10 6 M), but low concentrations of 17b-estradiol (10 10 M) induced significant repulsion of SNF (20–60%) in comparison to controls. Conclusions: The outgrowth assay enabled us to study the influence of pathogenetically relevant factors which may be involved in nerve fiber growth and repulsion. We assume that not only specific axon guidance molecules, but rather the interplay of other factors, which are elevated in inflamed tissue predominantly influence nerve fiber growth and repulsion during the course of RA. doi:10.1016/j.bbi.2011.07.024
22. Hypoxia induces tyrosine hydroxylase (TH) and modulates cytokine release in arthritis Z. Jenei-Lanzl, S. Capellino, R. Straub Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Department of Internal Medicine, University Hospital Regensburg, Regensburg, Germany It is known that the microenvironment of inflamed joints is hypoxic and that hypoxia induces tyrosine hydroxylase (TH) in vivo. Furthermore, we have shown that TH-positive, catecholamineproducing cells are present in inflamed synovial tissue parallel to sympathetic nerve fibre loss. Therefore, the aim of our study was to investigate whether hypoxia is responsible for TH expression and how it modulates inflammatory mediators. Synovial tissue was obtained from rheumatoid arthritis (RA) patients. Synovial cells were cultivated under normal or hypoxic conditions. Parallel to control samples, catecholamine receptor (beta-adrenergic, D1/5 dopamine) or adenosine receptor antagonists were applied in order to reverse possible effects on cytokine release. After 24 h, cells were stained for TH and cytokine concentrations were determined in supernatants. We demonstrated that hypoxia increased the number of TH positive synovial cells compared to cells cultured under normal conditions. Furthermore, in contrast to normal conditions, hypoxia exhibited inhibitory effects on TNF and IL-10, whereas IL-6 and IL8 were unaffected. Different receptor antagonists were not able to reverse hypoxia-induced inhibition of TNF or IL-10. This study demonstrates that hypoxia strongly induces TH production in RA synovial cells. Moreover, release of TNF and IL-10 is reduced during
S185
hypoxic conditions. We hypothesize that hypoxia influences the inflammatory response in RA synovial cells by modulating local production of TH-dependent hormones whose nature needs to be determined in further experiments. doi:10.1016/j.bbi.2011.07.025
23. Oxytocin and human inflammation: Does oxytocin attenuate inflammatory cytokine production in human monocytes? K.M. Ross, G. McDonald-Jones, G. Miller Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4 Oxytocin (OT) has anti-inflammatory properties in humans, as shown by its ability to block in vivo cytokine release following LPS infusion. Some of these effects have been localized to monocytes/macrophages. However, because the localization work has used cell lines and rodent adipose, its implications for humans are unclear. Here we present studies of OT’s anti-inflammatory effects in monocytes from healthy adults. First, whole blood was incubated with LPS (50 ng/mL) and varying doses of OT (1–1000 nM) for 6 h under standard conditions. Second, as prior OT exposure might be necessary before cytokine attenuation can occur, whole blood was pre-incubated with OT (30 and 60 min) before adding LPS. Intracellular IL6 production by CD14+ cells was analyzed by FACS. Third, as OT could regulate cytokine secretion rather than production, the studies were repeated with supernatant IL6 analyzed via ELISA. Under all conditions LPS induced IL6 production, but no suppressive effects of OT were observed. Fourth, to determine whether OT acts on other cytokines, supernatants were analyzed by multiplex ELISA. OT had no effect on LPS-stimulated production of IL1, TNF-a, or IL-8. Finally, as whole blood constituents might interfere with OT, the experiments were repeated in isolated PBMCs. OT did not inhibit IL6 production under these conditions either. Together, these findings indicate that OT’s anti-inflammatory properties are not exerted through actions on monocytes. doi:10.1016/j.bbi.2011.07.026
24. Sex differences in interleukin-6 production and glucocorticoid sensitivity in response to caregiving M.M. Murphy, C. Muñoz, G.E. Miller University of British Columbia, Department of Psychology, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4 Objective: Studies have documented sex differences in inflammatory responses to acute laboratory stress, but it is unclear whether these findings generalize to chronic real-world difficulties. Here we examine sex differences in interluekin-6 (IL6) production and glucocorticoid sensitivity (GS) in response to caregiving, a stressor that typically imposes different psychosocial demands on men and women. Methods: Data are from an ongoing prospective study following caregivers of cancer patients and healthy controls. This analysis focuses on baseline data from 19 caregivers and 34 controls, and values from 11 caregivers and 26 controls who have completed 6 month follow-ups. To assess IL6 production and GS, blood was incubated with lipopolysaccharide and various cortisol doses. Intracellular IL6 expression was measured by FACS in CD14+ gated cells. Results: At baseline, caregivers and controls had similar IL6 production. However, there was a marginal group by sex interaction, p = .08. This interaction became significant at follow-up, p = .02. At
21. Nerve fiber repulsion by semaphorins – More redundancy than expected in the rheumatoid arthritis joint? S. Klatt, A. Fassold, R.H. Straub Department of Internal Medicine I, University Hospital of Regensburg, Germany Lab. of NeuroEndocrineImmunology and Rheumatology, Franz-JosefStrauss-Allee 11, Regensburg 93042, Germany Background/purpose: The loss of sympathetic nerve fibers (SNF) is a general principle in inflammatory diseases. Since sympathetic neurotransmitters exert antiinflammatory effects at increased concentrations, their loss is unfavorable in chronic inflammatory diseases like rheumatoid arthritis (RA). Semaphorins are the major factors which are involved in guidance and repulsion of nerve fibers. Recent findings also indicate increased concentrations of norepinephrine, dopamine and 17b-estradiol in synovial tissue of RA patients. The aim of this project was to test the effects of these substances on growth and repulsion of SNF in vitro. Methods: The behavior of SNF from sympathetic trunk ganglia of postnatal mice was investigated in a neurite outgrowth assay using time-lapse microscopy. Results: Semaphorins 3F and 3C induced a nearly complete repulsion of SNF up to 100%. TNF repelled nerve fibers with variable effects (10–100%). High concentrations of catecholamines (10 6 M), but low concentrations of 17b-estradiol (10 10 M) induced significant repulsion of SNF (20–60%) in comparison to controls. Conclusions: The outgrowth assay enabled us to study the influence of pathogenetically relevant factors which may be involved in nerve fiber growth and repulsion. We assume that not only specific axon guidance molecules, but rather the interplay of other factors, which are elevated in inflamed tissue predominantly influence nerve fiber growth and repulsion during the course of RA. doi:10.1016/j.bbi.2011.07.024
22. Hypoxia induces tyrosine hydroxylase (TH) and modulates cytokine release in arthritis Z. Jenei-Lanzl, S. Capellino, R. Straub Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Department of Internal Medicine, University Hospital Regensburg, Regensburg, Germany It is known that the microenvironment of inflamed joints is hypoxic and that hypoxia induces tyrosine hydroxylase (TH) in vivo. Furthermore, we have shown that TH-positive, catecholamineproducing cells are present in inflamed synovial tissue parallel to sympathetic nerve fibre loss. Therefore, the aim of our study was to investigate whether hypoxia is responsible for TH expression and how it modulates inflammatory mediators. Synovial tissue was obtained from rheumatoid arthritis (RA) patients. Synovial cells were cultivated under normal or hypoxic conditions. Parallel to control samples, catecholamine receptor (beta-adrenergic, D1/5 dopamine) or adenosine receptor antagonists were applied in order to reverse possible effects on cytokine release. After 24 h, cells were stained for TH and cytokine concentrations were determined in supernatants. We demonstrated that hypoxia increased the number of TH positive synovial cells compared to cells cultured under normal conditions. Furthermore, in contrast to normal conditions, hypoxia exhibited inhibitory effects on TNF and IL-10, whereas IL-6 and IL8 were unaffected. Different receptor antagonists were not able to reverse hypoxia-induced inhibition of TNF or IL-10. This study demonstrates that hypoxia strongly induces TH production in RA synovial cells. Moreover, release of TNF and IL-10 is reduced during
S185
hypoxic conditions. We hypothesize that hypoxia influences the inflammatory response in RA synovial cells by modulating local production of TH-dependent hormones whose nature needs to be determined in further experiments. doi:10.1016/j.bbi.2011.07.025
23. Oxytocin and human inflammation: Does oxytocin attenuate inflammatory cytokine production in human monocytes? K.M. Ross, G. McDonald-Jones, G. Miller Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4 Oxytocin (OT) has anti-inflammatory properties in humans, as shown by its ability to block in vivo cytokine release following LPS infusion. Some of these effects have been localized to monocytes/macrophages. However, because the localization work has used cell lines and rodent adipose, its implications for humans are unclear. Here we present studies of OT’s anti-inflammatory effects in monocytes from healthy adults. First, whole blood was incubated with LPS (50 ng/mL) and varying doses of OT (1–1000 nM) for 6 h under standard conditions. Second, as prior OT exposure might be necessary before cytokine attenuation can occur, whole blood was pre-incubated with OT (30 and 60 min) before adding LPS. Intracellular IL6 production by CD14+ cells was analyzed by FACS. Third, as OT could regulate cytokine secretion rather than production, the studies were repeated with supernatant IL6 analyzed via ELISA. Under all conditions LPS induced IL6 production, but no suppressive effects of OT were observed. Fourth, to determine whether OT acts on other cytokines, supernatants were analyzed by multiplex ELISA. OT had no effect on LPS-stimulated production of IL1, TNF-a, or IL-8. Finally, as whole blood constituents might interfere with OT, the experiments were repeated in isolated PBMCs. OT did not inhibit IL6 production under these conditions either. Together, these findings indicate that OT’s anti-inflammatory properties are not exerted through actions on monocytes. doi:10.1016/j.bbi.2011.07.026
24. Sex differences in interleukin-6 production and glucocorticoid sensitivity in response to caregiving M.M. Murphy, C. Muñoz, G.E. Miller University of British Columbia, Department of Psychology, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4 Objective: Studies have documented sex differences in inflammatory responses to acute laboratory stress, but it is unclear whether these findings generalize to chronic real-world difficulties. Here we examine sex differences in interluekin-6 (IL6) production and glucocorticoid sensitivity (GS) in response to caregiving, a stressor that typically imposes different psychosocial demands on men and women. Methods: Data are from an ongoing prospective study following caregivers of cancer patients and healthy controls. This analysis focuses on baseline data from 19 caregivers and 34 controls, and values from 11 caregivers and 26 controls who have completed 6 month follow-ups. To assess IL6 production and GS, blood was incubated with lipopolysaccharide and various cortisol doses. Intracellular IL6 expression was measured by FACS in CD14+ gated cells. Results: At baseline, caregivers and controls had similar IL6 production. However, there was a marginal group by sex interaction, p = .08. This interaction became significant at follow-up, p = .02. At