title: Genetic analysis of mesangial matrix expansion in aging mice and identification of Far2 as a candidate gene.
abstract: Aging of the kidney is associated with renal damage, in particular mesangial matrix expansion (MME). Identifying the genes involved in this process will help to unravel the mechanisms of aging and aid in the design of novel therapeutic modalities aimed at prevention and regression. In this study, structural changes in glomeruli of 24 inbred mouse strains were characterized in male mice at 6, 12, and 20 months of age. Haplotype association mapping was used to determine genetic loci associated with the presence of MME at 20 months. This analysis identified a significant association with a 200-kb haplotype block on chromosome 6 containing Far2. Sequencing revealed that mouse strains with MME contain a 9-bp sequence in the 5' untranslated region of Far2 that is absent in most of the strains without MME. Real-time PCR showed a two-fold increase in the expression of Far2 in the kidneys of strains with the insert, and subsequent experiments performed in vitro with luciferase reporter vectors showed that this sequence difference causes differential expression of Far2. Overexpression of Far2 in a mouse mesangial cell line induced upregulation of platelet activating factor and the fibrotic marker TGF-β. This upregulation of MME-promoting factors may result, in part, from the FAR2-catalyzed reduction of fatty acyl-coenzyme A to fatty alcohols, which are possible precursors of platelet activating factor. Overall, these data suggest the identification of a novel pathway involved in renal aging that may yield therapeutic targets for reducing MME.
authors.affiliation: Department of Pathology and Medical Biology, University of Groningen and University Medical Center, Groningen, The Netherlands;
authors.forename: Gerda A
authors.initials: GA
authors.lastname: Noordmans
authors.forename: Christina R
authors.initials: CR
authors.lastname: Caputo
authors.forename: Yuan
authors.initials: Y
authors.lastname: Huang
authors.forename: Susan M
authors.initials: SM
authors.lastname: Sheehan
authors.forename: Marian
authors.initials: M
authors.lastname: Bulthuis
authors.forename: Peter
authors.initials: P
authors.lastname: Heeringa
authors.forename: Jan-Luuk
authors.initials: JL
authors.lastname: Hillebrands
authors.forename: Harry
authors.initials: H
authors.lastname: van Goor
authors.forename: Ron
authors.initials: R
authors.lastname: Korstanje
mesh_terms: D000375:Aging / Q000473:pathology* / Q000502:physiology; D000445:Aldehyde Oxidoreductases / Q000235:genetics*; D000818:Animals; D002874:Chromosome Mapping; D006239:Haplotypes; D007678:Kidney Glomerulus / Q000473:pathology* / Q000502:physiology*; D008297:Male; D050527:Mesangial Cells / Q000473:pathology* / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D019463:Mice, Inbred MRL lpr; D016688:Mice, Inbred NOD; D013045:Species Specificity
chemical_list: D000445:Aldehyde Oxidoreductases; C493804:FAR2 protein, mouse