Stephen Rubino

Publications (15) View all

• Article: Nod1 and Nod2 signaling does not alter the composition of intestinal bacterial communities at homeostasis.

  Susan J Robertson, Jun Yu Zhou, Kaoru Geddes, Stephen J Rubino, Joon Ho Cho, Stephen E Girardin, Dana J Philpott
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  ABSTRACT: Patients with inflammatory bowel diseases (IBD) harbour intestinal bacterial communities with altered composition compared with healthy counterparts; however, it is unknown whether changes in the microbiota are associated with genetic susceptibility of individuals for developing disease or instead reflect other changes in the intestinal environment related to the disease itself. Since deficiencies in the innate immune receptors Nod1 and Nod2 are linked to IBD, we tested the hypothesis that Nod-signaling alters intestinal immune profiles and subsequently alters bacterial community structure. We used qPCR to analyze expression patterns of selected immune mediators in the ileum and cecum of Nod-deficient mice compared with their Nod-sufficient littermates and assessed the relative abundance of major bacterial groups sampled from the ileum, cecum and colon. The Nod1-deficient ileum exhibited significantly lower expression of Nod2, Muc2, α- and β-defensins and keratinocyte-derived chemokine (KC), suggesting a weakened epithelial barrier compared with WT littermates; however, there were no significant differences in the relative abundance of targeted bacterial groups, indicating that Nod1-associated immune differences alone do not promote dysbiosis. Furthermore, Nod2-deficient mice did not display any changes in the expression of immune markers or bacterial communities. Shifts in bacterial communities that were observed in this study correlated with housing conditions and were independent of genotype. These findings emphasize the importance of using F2 littermate controls to minimize environmental sources of variation in microbial analyses, to establish baseline conditions for host-microbe homeostasis in Nod-deficient mice and to strengthen models for testing factors contributing to microbial dysbiosis associated with IBD.
  Gut Microbes 04/2013; 4(3).
• Article: Identification of a synthetic muramyl peptide derivative with enhanced Nod2 stimulatory capacity.

  Stephen J Rubino, Joao G Magalhaes, Dana Philpott, George M Bahr, Didier Blanot, Stephen E Girardin
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  ABSTRACT: Muramyl peptides (MPs) represent the building blocks of bacterial peptidoglycan, a critical component of bacterial cell walls. MPs are well characterized for their immunomodulatory properties, and numerous studies have delineated the role of MPs or synthetic MP analogs in host defense, adjuvanticity and inflammation. More recently, Nod1 and Nod2 have been identified as the host sensors for specific MPs, and, in particular, Nod2 was shown to detect muramyl dipeptide (MDP), a MP found in both Gram-positive and Gram-negative bacterial cell walls. Because mutations in Nod2 are associated with the etiology of Crohn's disease, there is a need to identify synthetic MP analogs that could potentiate Nod2-dependent immunity. Here, we analyzed the Nod2-activating property of 36 MP analogs that had been tested previously for their adjuvanticity and anti-infectious activity. Using a luciferase-based screen, we demonstrate that addition of a methyl group to the second amino acid of MDP generates a MDP derivative with enhanced Nod2-activating capacity. We further validated these results in murine macrophages, human dendritic cells and in vivo. These results offer a basis for the rational development of synthetic MPs that could be used in the treatment of inflammatory disorders that have been associated with Nod2 dysfunction, such as Crohn's disease.
  Innate Immunity 01/2013; · 4.00 Impact Factor
• Source

  Available from: Susan J Robertson

  Article: Gut Microbes

  Susan J. Robertson, Jun Yu Zhou, Kaoru Geddes, Stephen J. Rubino, Joon Ho Cho, Stephen E. Girardin, Dana J. Philpott
  Gut Microbes 01/2013;
• Article: Phenotyping of Nod1/2 double deficient mice and characterization of Nod1/2 in systemic inflammation and associated renal disease.

  Ingrid Stroo, Loes M Butter, Nike Claessen, Gwen J Teske, Stephen J Rubino, Stephen E Girardin, Sandrine Florquin, Jaklien C Leemans
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  ABSTRACT: It is indispensable to thoroughly characterize each animal model in order to distinguish between primary and secondary effects of genetic changes. The present study analyzed Nod1 and Nod2 double deficient (Nod1/2 DKO) mice under physiological and inflammatory conditions. Nod1 and Nod2 are members of the Nucleotide-binding domain and Leucine-rich repeat containing Receptor (NLR) family. Several inflammatory disorders, such as Crohn's disease and asthma, are linked to genetic changes in either Nod1 or Nod2. These associations suggest that Nod1 and Nod2 play important roles in regulating the immune system.Three-month-old wildtype (Wt) and Nod1/2 DKO mice were sacrificed, body and organ weight were determined, and blood was drawn. Except for lower liver weight in Nod1/2 DKO mice, no differences were found in body/organ weight between both strains. Leukocyte count and composition was comparable. No significant changes in analyzed plasma biochemical markers were found. Additionally, intestinal and vascular permeability was determined. Nod1/2 DKO mice show increased susceptibility for intestinal permeability while vascular permeability was not affected. Next we induced septic shock and organ damage by administering LPS+PGN intraperitoneally to Wt and Nod1/2 DKO mice and sacrificed animals after 2 and 24 hours. The systemic inflammatory and metabolic response was comparable between both strains. However, renal response was different as indicated by partly preserved kidney function and tubular epithelial cell damage in Nod1/2 DKO at 24 hours. Remarkably, renal inflammatory mediators Tnfα, KC and Il-10 were significantly increased in Nod1/2 DKO compared with Wt mice at 2 hours.Systematic analysis of Nod1/2 DKO mice revealed a possible role of Nod1/2 in the development of renal disease during systemic inflammation.
  Biology open. 12/2012; 1(12):1239-47.
• Source

  Available from: Stephen Rubino

  Article: Nod-like receptors in the control of intestinal inflammation.

  Stephen J Rubino, Thirumahal Selvanantham, Stephen E Girardin, Dana J Philpott
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  ABSTRACT: The Nod-like receptor (NLR) family of intracellular pattern recognition molecules plays critical roles in the control of inflammation through the modulation of different signalling pathways, including those dependent on NF-κB and caspase-1-mediated cleavage of interleukin (IL)-1β and IL-18. A number of NLRs or NLR-associated proteins have been genetically associated with susceptibility to inflammatory bowel disease (IBD), either Crohn's disease or ulcerative colitis. Accordingly, recent studies have examined the role of NLR proteins in chemical-induced or bacteria-induced murine models of colitis. In this review, we will discuss the genetic associations of NLRs with IBD and the research using NLR-deficient mice in different colitis models.
  Current opinion in immunology 06/2012; 24(4):398-404. · 10.88 Impact Factor