Clinical relevance of non-neuronal auto-antibodies in patients with anti-Hu or anti-Yo paraneoplastic diseases

About half of the patients with paraneoplastic diseases develop an immune response against neuronal antigens expressed by both the tumor and the nervous system. In 31 patients with anti-Hu antibodies and 19 patients with anti-Yo antibodies, we searched for the presence of additional non-neuronal auto-antibodies and further studied whether the presence of such auto-antibodies was correlated with a specific oncological or neurological presentation. Positive antinuclear antibodies (ANA) were found at a titer of 1:40 or above in 48% patients with anti-Hu antibodies, and in 37% patients with anti-Yo antibodies. Anti-cytoplasmic antibodies were also detected in 42% patients with anti-Yo antibodies. No specific correlation between the presence of non-neuronal auto-antibodies and clinical characteristics of the patients could be identified. In particular, neither the type of underlying cancer, the overall survival, the tumor response to treatment, nor the neurological presentation were related to the serological status.     

Systemic perturbation of cytokine and chemokine networks in Erdheim-Chester disease: a single-center series of 37 patients

Immunopathogenesis of Erdheim-Chester disease (ECD), a rare non-Langerhans cell histiocytosis, is poorly known. In previous studies, various cytokines were detected in ECD lesions, presumably orchestrating lesional histiocyte recruitment. Because ECD lesions are frequently associated with systemic symptoms, we postulated that underlying global immune perturbations might also be revealed. We quantitatively analyzed 23 cytokines in serum samples obtained from a large single-center cohort of 37 patients with ECD, and studied the impact of treatment on cytokine production. IL-6, IL-12, interferon-α (IFN-α), and monocyte chemotactic protein-1 (MCP-1) levels were significantly higher in untreated patients than in controls, whereas interferon-γ (IFN-γ) inducible protein 10, IL-12, MCP-1, and IL-1 receptor antagonist were found significantly increased in IFN-α-treated patients. A biomathematical approach was used to rationalize multiparameter data, to generate new hypotheses, and identify global control pathways. Interestingly, cytokine profiles proved to be particularly stable at the individual level, and an "ECD signature" further distinguished patients from controls, based on their production of IFN-α, IL-12, MCP-1, IL-4, and IL-7. Altogether, our data underline the systemic immune Th-1-oriented perturbation associated with this condition and provide clues for the choice of more focused therapeutic agents in this rare disease with noncodified therapeutic management.     

Conditions of wound healing and cutaneous growth affect metabolic performance of skin following plastic surgery

The mechanical and structural properties of skin subjected to expansion have been widely investigated in the context of plastic surgery. To determine the actual metabolic state of skin following skin expander placement, we determined the basic biochemical parameters for various conditions of postsurgical wound healing and cutaneous growth. Studying, for the first time, comprehensive metabolic profiles ("metabolomics") of the skin in a minipig model, we found that the lactate/alanine ratios were significantly increased (p<0.05) in skin attached to noninflated expanders vs. control skin, indicating increased anaerobic glycolysis. Furthermore, creatine/phosphocreatine ratios were decreased in skin from inflated vs. noninflated expanders, implying an improved energetic state for stretched skin. In contrast, no significant differences were detected for these parameters on comparing skin from four inflated expanders with different surface structures, even where the histologically determined capsule thickness was significantly different. Overall, the metabolic performance of skin recovering and growing under stretch was found to be superior to that of skin from noninflated expanders, and comparable to that of control skin. Our results are consistent with the assumptions of (i) major hypoxia/ischemia due to reduced perfusion in skin recovering from surgery without an appropriate supportive structure and (ii) minimal metabolic effects of expander surface structures.     

A comparative analysis of the substrate permissiveness of HCV and GBV-B NS3/4A proteases reveals genetic evidence for an interaction with NS4B protein during genome replication

The hepatitis C virus (HCV) serine protease (NS3/4A) processes the NS3-NS5B segment of the viral polyprotein and also cleaves host proteins involved in interferon signaling, making it an important target for antiviral drug discovery and suggesting a wide breadth of substrate specificity. We compared substrate specificities of the HCV protease with that of the GB virus B (GBV-B), a distantly related nonhuman primate hepacivirus, by exchanging amino acid sequences at the NS4B/5A and/or NS5A/5B cleavage junctions between these viruses within the backbone of subgenomic replicons. This mutagenesis study demonstrated that the GBV-B protease had a broader substrate tolerance, a feature corroborated by structural homology modeling. However, despite efficient polyprotein processing, GBV-B RNAs containing HCV sequences at the C-terminus of NS4B had a pseudo-lethal replication phenotype. Replication-competent revertants contained second-site substitutions within the NS3 protease or NS4B N-terminus, providing genetic evidence for an essential interaction between NS3 and NS4B during genome replication.     

Differential effects of cocaine on histone posttranslational modifications in identified populations of striatal neurons

Drugs of abuse, such as cocaine, induce changes in gene expression and epigenetic marks including alterations in histone posttranslational modifications in striatal neurons. These changes are thought to participate in physiological memory mechanisms and to be critical for long-term behavioral alterations. However, the striatum is composed of multiple cell types, including two distinct populations of medium-sized spiny neurons, and little is known concerning the cell-type specificity of epigenetic modifications. To address this question we used bacterial artificial chromosome transgenic mice, which express EGFP fused to the N-terminus of the large subunit ribosomal protein L10a driven by the D1 or D2 dopamine receptor (D1R, D2R) promoter, respectively. Fluorescence in nucleoli was used to sort nuclei from D1R- or D2R-expressing neurons and to quantify by flow cytometry the cocaine-induced changes in histone acetylation and methylation specifically in these two types of nuclei. The two populations of medium-sized spiny neurons displayed different patterns of histone modifications 15 min or 24 h after a single injection of cocaine or 24 h after seven daily injections. In particular, acetylation of histone 3 on Lys 14 and of histone 4 on Lys 5 and 12, and methylation of histone 3 on Lys 9 exhibited distinct and persistent changes in the two cell types. Our data provide insights into the differential epigenetic responses to cocaine in D1R- and D2R-positive neurons and their potential regulation, which may participate in the persistent effects of cocaine in these neurons. The method described should have general utility for studying nuclear modifications in different types of neuronal or nonneuronal cell types.