Modulation of inflammation by immunostimulatory DNA

The aim of this thesis was to elucidate the roles of different types of DNA in inflammatory responses. We compared the immune responses to nuclease-protected phosphorothioate oligodeoxynucleotides (S-ODNs) and phosphodiester oligodeoxynucleotides (O-ODNs) that either contained or lacked CpG motifs. The combination of CpG motif and S-ODN backbone was strongly synergistic for immunostimulation and caused the highest frequency of arthritis in intra-articularly injected mice. CpG-S induced arthritis correlated with a strong induction of NFkappaB, whereas S-ODN-induced immune activation and arthritis appeared to be independent of NFkappaB. Furthermore, we studied the in vivo and in vitro inflammatogenic properties of CpG ODNs, that contained a specific nucleobase deletion either upstream or downstream of the CpG motif. Depending on the location, nucleobase deletions reduced the arthritogenicity of CpG-S DNA, while retaining potent immunostimulatory activity, in terms of the induction of cytokines, chemokines and lymphocyte proliferation. CpG-S stimulation of splenocyte proliferation was significantly reduced by the addition of O-ODNs. Furthermore, CpG-S-induced production of IL-6 and IL-10, which both promote B-cell differentiation, was also downregulated when O-ODNs were added in combination with CpG-S. Since the O-ODN-mediated inhibition of proliferation was less pronounced in IL-10-/- mice, it appears that the anti-proliferative effects of O-ODNs are partially mediated by the downregulation of IL-10 production. B-cell responses to CpG DNA-containing immune complexes may play a role in chronic autoimmunity and in immune responses to bacterial components. Therefore, we investigated the potential interaction between CpG DNA stimulation and FcgammaR clustering on B-cell activities. We found that CpG DNA and FcgammaR clustering synergized to enhance B-cell proliferation, having also impact on several maturation stages in the late differentiation stage of splenic B cells. In conclusion, the inflammatogenic and arthritogenic properties of DNA could be modulated by changing the DNA sequence or backbone, or by modifying the nucleobases. Thus, ODNs may be tailor-made to provide directed immune responses. Furthermore, CpG DNA and FcgammaR clustering were synergistic with respect to B-cell activation. CpG DNA-containing immune complexes may play a role in the host defense against pathogens and as adjuvants in vaccines. However, certain properties of immunostimulatory DNA may, in a given host environment, lead to the development or aggravation of autoimmune disease

Smoking is Associated with Reduced Leptin and Neuropeptide Y Levels and Higher Pain Experience in Patients with Fibromyalgia

Smoking deregulates neuroendocrine responses to pain supporting production of neuropeptide Y (NpY) by direct stimulation of nicotinic receptors or by inhibiting adipokine leptin. Present study addressed the effect of cigarette smoking on adipokines and pain parameters, in 62 women with fibromyalgia (FM) pain syndrome with unknown etiology. Pain was characterized by a visual analogue scale, tender point (TP) counts, pressure pain threshold, and neuroendocrine markers NpY and substance P (sP). Levels of IGF-1, leptin, resistin, visfatin, and adiponectin were measured in blood and cerebrospinal fluid. Current smokers ( = 18) had lower levels of leptin compared to ex-smokers ( = 25, = 0.002), while the expected NpY increase was absent in FM patients. In smokers, this was transcribed in higher VAS-pain ( = 0.04) and TP count ( = 0.03), lower pain threshold ( = 0.01), since NpY levels were directly related to the pain threshold (rho = 0.414) and inversely related to TP counts (rho = −0.375). This study shows that patients with FM have no increase of NpY levels in response to smoking despite the low levels of leptin. Deregulation of the balance between leptin and neuropeptide Y may be one of the essential mechanisms of chronic pain in FM

Smoking is Associated with Reduced Leptin and Neuropeptide Y Levels and Higher Pain Experience in Patients with Fibromyalgia

Smoking deregulates neuroendocrine responses to pain supporting production of neuropeptide Y (NpY) by direct stimulation of nicotinic receptors or by inhibiting adipokine leptin. Present study addressed the effect of cigarette smoking on adipokines and pain parameters, in 62 women with fibromyalgia (FM) pain syndrome with unknown etiology. Pain was characterized by a visual analogue scale, tender point (TP) counts, pressure pain threshold, and neuroendocrine markers NpY and substance P (sP). Levels of IGF-1, leptin, resistin, visfatin, and adiponectin were measured in blood and cerebrospinal fluid. Current smokers (n=18) had lower levels of leptin compared to ex-smokers (n=25, P=0.002), while the expected NpY increase was absent in FM patients. In smokers, this was transcribed in higher VAS-pain (P=0.04) and TP count (P=0.03), lower pain threshold (P=0.01), since NpY levels were directly related to the pain threshold (rho=0.414) and inversely related to TP counts (rho=-0.375). This study shows that patients with FM have no increase of NpY levels in response to smoking despite the low levels of leptin. Deregulation of the balance between leptin and neuropeptide Y may be one of the essential mechanisms of chronic pain in FM

Profile of Cerebrospinal microRNAs in Fibromyalgia

<div><p>Introduction</p><p>Fibromyalgia (FM) is characterized by chronic pain and reduced pain threshold. The pathophysiology involves disturbed neuroendocrine function, including impaired function of the growth hormone/insulin-like growth factor-1 axis. Recently, microRNAs have been shown to be important regulatory factors in a number of diseases.</p> <p>The aim of this study was to try to identify cerebrospinal microRNAs with expression specific for FM and to determine their correlation to pain and fatigue. </p> <p>Methods</p><p>The genome-wide profile of microRNAs in cerebrospinal fluid was assessed in ten women with FM and eight healthy controls using real-time quantitative PCR. Pain thresholds were examined by algometry. Levels of pain (FIQ pain) were rated on a 0-100 mm scale (fibromyalgia impact questionnaire, FIQ). Levels of fatigue (FIQ fatigue) were rated on a 0-100 mm scale using FIQ and by multidimensional fatigue inventory (MFI-20) general fatigue (MFIGF).</p> <p>Results</p><p>Expression levels of nine microRNAs were significantly lower in patients with FM patients compared to healthy controls. The microRNAs identified were miR-21-5p, miR-145-5p, miR-29a-3p, miR-99b-5p, miR-125b-5p, miR-23a-3p, 23b-3p, miR-195-5p, miR-223-3p.</p> <p>The identified microRNAs with significantly lower expression in FM were assessed with regard to pain and fatigue. miR-145-5p correlated positively with FIQ pain (r=0.709, p=0.022, n=10) and with FIQ fatigue (r=0.687, p=0.028, n=10). </p> <p>Conclusion</p><p>To our knowledge, this is the first study to show a disease-specific pattern of cerebrospinal microRNAs in FM.</p> <p>We have identified nine microRNAs in cerebrospinal fluid that differed between FM patients and healthy controls. One of the identified microRNAs, miR-145 was associated with the cardinal symptoms of FM, pain and fatigue.</p> </div