Showing papers by "Gilles Dietrich published in 2012"

Food-Grade Bacteria Expressing Elafin Protect Against Inflammation and Restore Colon Homeostasis

Abstract: Elafin, a natural protease inhibitor expressed in healthy intestinal mucosa, has pleiotropic anti-inflammatory properties in vitro and in animal models. We found that mucosal expression of Elafin is diminished in patients with inflammatory bowel disease (IBD). This defect is associated with increased elastolytic activity (elastase-like proteolysis) in colon tissue. We engineered two food-grade strains of lactic acid bacteria (LAB) to express and deliver Elafin to the site of inflammation in the colon to assess the potential therapeutic benefits of the Elafin-expressing LAB. In mouse models of acute and chronic colitis, oral administration of Elafin-expressing LAB decreased elastolytic activity and inflammation and restored intestinal homeostasis. Furthermore, when cultures of human intestinal epithelial cells were treated with LAB secreting Elafin, the inflamed epithelium was protected from increased intestinal permeability and from the release of cytokines and chemokines, both of which are characteristic of intestinal dysfunction associated with IBD. Together, these results suggest that oral delivery of LAB secreting Elafin may be useful for treating IBD in humans.

Immune conditions associated with CD4+ T effector-induced opioid release and analgesia.

Abstract: Effector CD4+ T lymphocytes generated in response to antigens produce endogenous opioids. Thus, in addition to their critical role in host defenses against pathogens, effector CD4+ T lymphocytes contribute to relieving inflammatory pain. In this study, we investigated mechanisms of opioid release by antigen-experienced effector CD4+ T cells that leave draining lymph nodes and come back into the inflammatory site. Effector antigen-primed CD4+ T lymphocytes generated in vitro were intravenously injected into nude mice previously immunized with either cognate or irrelevant antigens in complete Freund adjuvant (CFA). CFA-induced mechanical hyperalgesia was only reduced in mice immunized with cognate antigen. Thus, antinociceptive activity of effector CD4+ T cells requires the presence of the antigen for which they are specific within the inflammatory site. Accordingly, analgesia was inhibited by neutralizing cognate T cell receptor-mediated interaction between effector CD4+ T lymphocytes and antigen-presenting cells at the site of inflammation. Analgesia was observed by transferring effector CD4+ T lymphocytes with Th1 or Th2 phenotype, suggesting that antinociceptive activity is a fundamental property of effector CD4+ T lymphocytes irrespective of their effector functions. Based on the use of agonists and antagonists selective for each of the opioid receptor subclasses, we showed that analgesia induced by T cell-derived opioids is elicited via activation of δ-type opioid receptors in the periphery. Thus, the antinociceptive activity is a fundamental property associated with the effector phase of adaptive immunity, which is driven by recognition of the cognate antigen by effector CD4+ T lymphocytes at the inflammatory site.

Denatured G-protein coupled receptors as immunogens to generate highly specific antibodies.

Abstract: G-protein coupled receptors (GPCRs) play a major role in a number of physiological and pathological processes. Thus, GPCRs have become the most frequent targets for development of new therapeutic drugs. In this context, the availability of highly specific antibodies may be decisive to obtain reliable findings on localization, function and medical relevance of GPCRs. However, the rapid and easy generation of highly selective anti-GPCR antibodies is still a challenge. Herein, we report that highly specific antibodies suitable for detection of GPCRs in native and unfolded forms can be elicited by immunizing animals against purified full length denatured recombinant GPCRs. Contrasting with the currently admitted postulate, our study shows that an active and well-folded GPCR is not required for the production of specific anti-GPCR antibodies. This new immunizing strategy validated with three different human GPCR (μ-opioid, κ-opioid, neuropeptide FF2 receptors) might be generalized to other members of the GPCR family.