title: Variation in IL-1beta gene expression is a major determinant of genetic differences in arthritis aggressivity in mice.
abstract: In humans and in animal models, susceptibility to arthritis is under complex genetic control, reflecting influences on the immunological processes that initiate autoimmunity and on subsequent inflammatory mechanisms in the joints. The effector phases are conveniently modeled by the K/BxN serum transfer system, a robust model well suited for genetic analysis where arthritis is initiated by pathogenic Ig. Here, we mapped the genetic loci distinguishing the high-responder BALB/c vs. low-responder SJL strains. After computational modeling of potential breeding schemes, we adapted a stepwise selective breeding strategy, with a whole-genome scan performed on a limited number of animals. Several genomic regions proved significantly associated with high sensitivity to arthritis. One of these regions, on distal chr2, was centered on the interleukin 1 gene family. Quantitation of transcripts of the Il1a and Il1b candidate genes revealed a 10-fold greater induction of Il1b mRNA in BALB/c than in SJL splenocytes after injection of LPS, whereas Il1a showed much less difference. The differential activity of the Il1b gene was associated with a particular sequence haplotype of noncoding polymorphisms. The BALB/c haplotype was found in 75% of wild-derived strains but was rare among conventional inbred strains (4/33 tested, one of which is DBA/1, the prototype arthritis-susceptible strain) and was associated with vigorous Il1b responses in a panel of inbred strains. Inbred strains carrying this allele were far more responsive to serum-transferred arthritis, confirming its broad importance in controlling arthritis severity.
authors.affiliation: Sections on Immunology and Immunogenetics, Joslin Diabetes Center, Department of Medicine, Brigham and Women's Hospital; Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Ohmura
authors.forename: Alyssa
authors.initials: A
authors.lastname: Johnsen
authors.forename: Adriana
authors.initials: A
authors.lastname: Ortiz-Lopez
authors.forename: Paul
authors.initials: P
authors.lastname: Desany
authors.forename: Matt
authors.initials: M
authors.lastname: Roy
authors.forename: Whitney
authors.initials: W
authors.lastname: Besse
authors.forename: John
authors.initials: J
authors.lastname: Rogus
authors.forename: Molly
authors.initials: M
authors.lastname: Bogue
authors.forename: Anne
authors.initials: A
authors.lastname: Puech
authors.forename: Mark
authors.initials: M
authors.lastname: Lathrop
authors.forename: Diane
authors.initials: D
authors.lastname: Mathis
authors.forename: Christophe
authors.initials: C
authors.lastname: Benoist
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000235:genetics* / Q000276:immunology*; D002874:Chromosome Mapping; D003198:Computer Simulation; D015870:Gene Expression; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics*; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D008957:Models, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D013045:Species Specificity
chemical_list: D007375:Interleukin-1; D012333:RNA, Messenger