Serum Neurotrophin Profile in Systemic Sclerosis

International audienceBACKGROUND: Neurotrophins (NTs) are able to activate lymphocytes and fibroblasts; they can modulate angiogenesis and sympathic vascular function. Thus, they can be implicated in the three pathogenic processes of systemic sclerosis (SSc). The aims of this study are to determine blood levels of Nerve Growth Factor (NGF), Brain-Derived Neurotrophic Factor (BDNF) and Neurotrophin-3 (NT-3) in SSc and to correlate them with clinical and biological data.METHODS: Serum samples were obtained from 55 SSc patients and 32 control subjects to measure NTs levels by ELISA and to determine their relationships with SSc profiles. FINDINGS: Serum NGF levels were higher in SSc patients (288.26 ± 170.34 pg/mL) than in control subjects (170.34 ± 50.8 pg/mL, p<0.001) and correlated with gammaglobulins levels and the presence of both anti-cardiolipin and anti-Scl-70 antibodies (p<0.05). In contrast, BDNF levels were lower in SSc patients than in controls (1121.9 ± 158.1 vs 1372.9 ± 190.9 pg/mL, p<0.0001), especially in pulmonary arterial hypertension and diffuse SSc as compared to limited forms (all p<0.05). NT-3 levels were similar in SSc and in the control group (2657.2 ± 2296 vs 2959.3 ± 2555 pg/mL, NS). BDNF levels correlated negatively with increased NGF levels in the SSc group (and not in controls). CONCLUSION: Low BDNF serum levels were not previously documented in SSc, particularly in the diffuse SSc subset and in patients with pulmonary hypertension or anti-Scl-70 antibodies. The negative correlation between NGF and BDNF levels observed in SSc and not in healthy controls could be implicated in sympathic vascular dysfunction in SSc

Neurotrophines lymphocitaires, salivaires et sériques au cours du syndrome de Gougerot-Sjögren primitif (étude préliminaire)

LIMOGES-BU Médecine pharmacie (870852108) / SudocSudocFranceF

Is rituximab an effective treatment of refractory calcinosis?

Calcinosis, the deposition of calcified material in soft tissues, is frequently seen in systemic sclerosis and dermatomyositis. Treatment options are limited, with disappointing results. Some recent case reports suggest that rituximab may be an attractive therapeutic option. In case 1, a 54-year-old woman who presented with rheumatoid arthritis in association with scleromyositis was treated with rituximab for rheumatoid arthritis. Despite this, she developed multiple progressive calcinosis, necessitating extracorporeal shock wave lithotripsy to limit calcinosis extension and pain. In case 2, a 38-year-old man, previously treated for an anti-Pm/Scl-positive polymyositis/scleroderma overlap syndrome, presented with multiple tumoural periarticular calcinosis, which progressed despite bisphosphonates, sodium thiosulfate and thalidomide. We decided to start rituximab. Progression of calcinosis was still evident 6 and 12 months after anti-CD20 treatment. Many treatments have been tried to treat calcinosis without demonstrated effectiveness. Presently, rituximab cannot be recommended for this indication in the absence of successful controlled trials

Sortase-Mediated Pilus Fiber Biogenesis in Streptococcus pneumoniae

SummaryStreptococcus pneumoniae is a piliated pathogen whose ability to circumvent vaccination and antibiotic treatment strategies is a cause of mortality worldwide. Pili play important roles in pneumococcal infection, but little is known about their biogenesis mechanism or the relationship between components of the pilus-forming machinery, which includes the fiber pilin (RrgB), two minor pilins (RrgA, RrgC), and three sortases (SrtC-1, SrtC-2, SrtC-3). Here we show that SrtC-1 is the main pilus-polymerizing transpeptidase, and electron microscopy analyses of RrgB fibers reconstituted in vitro reveal that they structurally mimic the pneumococcal pilus backbone. Crystal structures of both SrtC-1 and SrtC-3 reveal active sites whose access is controlled by flexible lids, unlike in non-pilus sortases, and suggest that substrate specificity is dictated by surface recognition coupled to lid opening. The distinct structural features of pilus-forming sortases suggest a common pilus biogenesis mechanism that could be exploited for the development of broad-spectrum antibacterials

Structural Basis of Host Cell Recognition by the Pilus Adhesin from Streptococcus pneumoniae

SummaryPili are fibrous virulence factors associated directly to the bacterial surface that play critical roles in adhesion and recognition of host cell receptors. The human pathogen Streptococcus pneumoniae carries a single pilus-related adhesin (RrgA) that is key for infection establishment and provides protection from bacterial challenge in animal infection models, but details of these roles remain unclear. Here we report the high-resolution crystal structure of RrgA, a 893-residue elongated macromolecule whose fold contains four domains presenting both eukaryotic and prokaryotic origins. RrgA harbors an integrin I collagen-recognition domain decorated with two inserted “arms” that fold into a positively charged cradle, as well as three “stalk-forming” domains. We show by site-specific mutagenesis, mass spectrometry, and thermal shift assays that intradomain isopeptide bonds play key roles in stabilizing RrgA's stalk. The high sequence similarity between RrgA and its homologs in other Gram-positive microorganisms suggests common strategies for ECM recognition and immune evasion

Differential Expression of Neurotensin and Specific Receptors, NTSR1 and NTSR2, in Normal and Malignant Human B Lymphocytes

International audienceNeurotensin, a neuropeptide growth factor, and its two specific neurotensin receptors, NTSR1 and NTSR2, were shown to be expressed by human B cell lines. Another NTSR, sortilin, which is common to neurotensin and neurotrophins, was also detected as we have previously described. Neurotensin was functional in B cell lines; it induced their proliferation and inhibited apoptosis induced by serum deprivation or Fas activation. Quantitative study of gene expression in two malignant B cell diseases showed that NTSR2 was overexpressed, NTSR1 decreased, and neurotensin was unexpressed in B cell leukemia patient’s cells, as compared with healthy B cells. However, these expressions did not significantly change in large diffuse B cell lymphoma lymph nodes compared with benign ones. This study points out that neurotensin and its two specific receptors are expressed in human B lymphocytes. Such expressions were not described, and their relationship in B cell diseases, especially in chronic B cell leukemia, needs to be considered further in regard to these findings.

Active Immunological Profile Is Associated with Systemic Sjögren’s Syndrome

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Serum NT-3 concentrations (ELISA) in SLE patient with severe systemic flare (SLEDAI>10, grey box), moderate flare (SLEDAI≤10, dotted box) and healthy controls (Controls, white box).

<p>The boxes represent the 50th percentile, the bars outside the boxes show the 10th and 90th percentiles, and the horizontal black lines represent the median. Significant differences were assessed with Mann-Whitney tests.</p