title: Blau syndrome-associated Nod2 mutation alters expression of full-length NOD2 and limits responses to muramyl dipeptide in knock-in mice.
abstract: The biochemical mechanism by which mutations in nucleotide-binding oligomerization domain containing 2 (NOD2) cause Blau syndrome is unknown. Several studies have examined the effect of mutations associated with Blau syndrome in vitro, but none has looked at the implication of the mutations in vivo. To test the hypothesis that mutated NOD2 causes alterations in signaling pathways downstream of NOD2, we created a Nod2 knock-in mouse carrying the most common mutation seen in Blau syndrome, R314Q (corresponding to R334Q in humans). The endogenous regulatory elements of mouse Nod2 were unaltered. R314Q mice showed reduced cytokine production in response to i.p. and intravitreal muramyl dipeptide (MDP). Macrophages from R314Q mice showed reduced NF-κB and IL-6 responses, blunted phosphorylation of MAPKs, and deficient ubiquitination of receptor-interacting protein 2 in response to MDP. R314Q mice expressed a truncated 80-kDa form of NOD2 that was most likely generated by a posttranslational event because there was no evidence for a stop codon or alternative splicing event. Human macrophages from two patients with Blau syndrome also showed a reduction of both cytokine production and phosphorylation of p38 in response to MDP, indicating that both R314Q mice and cells from patients with Blau syndrome show reduced responses to MDP. These data indicate that the R314Q mutation when studied with the Nod2 endogenous regulatory elements left intact is associated with marked structural and biochemical changes that are significantly different from those observed from studies of the mutation using overexpression, transient transfection systems.
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239; Department of Medicine, Oregon Health and Sciences University, Portland, OR 97239;
authors.forename: Jae
authors.initials: J
authors.lastname: Dugan
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239;
authors.forename: Eric
authors.initials: E
authors.lastname: Griffiths
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239;
authors.forename: Paige
authors.initials: P
authors.lastname: Snow
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239; Department of Ophthalmology, Oregon Health and Sciences University, Portland, OR 97239; Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR 97239;
authors.forename: Holly
authors.initials: H
authors.lastname: Rosenzweig
authors.affiliation: Department of Ophthalmology, Oregon Health and Sciences University, Portland, OR 97239;
authors.forename: Ellen
authors.initials: E
authors.lastname: Lee
authors.affiliation: Department of Ophthalmology, Oregon Health and Sciences University, Portland, OR 97239;
authors.forename: Brieanna
authors.initials: B
authors.lastname: Brown
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239; Department of Medicine, Oregon Health and Sciences University, Portland, OR 97239;
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Carr
authors.affiliation: Division of Rheumatology, DuPont Hospital for Children, Wilmington, DE 19803; and.
authors.forename: Carlos
authors.initials: C
authors.lastname: Rose
authors.affiliation: Department of Medicine, Oregon Health and Sciences University, Portland, OR 97239; Department of Ophthalmology, Oregon Health and Sciences University, Portland, OR 97239; Legacy Devers Eye Institute, Portland, OR 97210.
authors.forename: James
authors.initials: J
authors.lastname: Rosenbaum
authors.affiliation: Portland Veterans Affairs Medical Center, Portland, OR 97239; Department of Medicine, Oregon Health and Sciences University, Portland, OR 97239; Department of Molecular Microbiology and Immunology, Oregon Health and Sciences University, Portland, OR 97239; michael.davey@va.gov.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Davey
mesh_terms: D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000276:immunology / Q000494:pharmacology*; D000818:Animals; D001168:Arthritis / Q000235:genetics*; D002460:Cell Line; D055879:Gene Knock-In Techniques; D057809:HEK293 Cells; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D016328:NF-kappa B / Q000096:biosynthesis; D053473:Nod2 Signaling Adaptor Protein / Q000096:biosynthesis / Q000235:genetics*; D010766:Phosphorylation / Q000235:genetics; D011499:Protein Processing, Post-Translational; D034622:RNA Interference; D034741:RNA, Small Interfering; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2 / Q000378:metabolism; D012507:Sarcoidosis; D015398:Signal Transduction / Q000235:genetics; D013585:Synovitis / Q000235:genetics*; D054875:Ubiquitination; D014605:Uveitis / Q000235:genetics*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*; D056660:Hereditary Autoinflammatory Diseases
chemical_list: D015850:Interleukin-6; D016328:NF-kappa B; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D034741:RNA, Small Interfering; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D053475:Receptor-Interacting Protein Serine-Threonine Kinase 2; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases