Identification of nephropathy candidate genes by comparing sclerosis-prone and sclerosis-resistant mouse strain kidney transcriptomes

Abstract Background The genetic architecture responsible for chronic kidney disease (CKD) remains incompletely described. The Oligosyndactyly (Os) mouse models focal and segmental glomerulosclerosis (FSGS), which is associated with reduced nephron number caused by the Os mutation. The Os mutation leads to FSGS in multiple strains including the ROP-Os/+. However, on the C57Bl/6J background the mutation does not cause FSGS, although nephron number in these mice are equivalent to those in ROP-Os/+ mice. We exploited this phenotypic variation to identify genes that potentially contribute to glomerulosclerosis. Methods To identify such novel genes, which regulate susceptibility or resistance to renal disease progression, we generated and compared the renal transcriptomes using serial analysis of gene expression (SAGE) from the sclerosis-prone ROP-Os/+ and sclerosis resistant C57-Os/+ mouse kidneys. We confirmed the validity of the differential gene expression using multiple approaches. We also used an Ingenuity Pathway Analysis engine to assemble differentially regulated molecular networks. Cell culture techniques were employed to confirm functional relevance of selected genes. Results A comparative analysis of the kidney transcriptomes revealed multiple genes, with expression levels that were statistically different. These novel, candidate, renal disease susceptibility/resistance genes included neuropilin2 (Nrp2), glutathione-S-transferase theta (Gstt1) and itchy (Itch). Of 34 genes with the most robust statistical difference in expression levels between ROP-Os/+ and C57-Os/+ mice, 13 and 3 transcripts localized to glomerular and tubulointerstitial compartments, respectively, from micro-dissected human FSGS biopsies. Network analysis of all significantly differentially expressed genes identified 13 connectivity networks. The most highly scored network highlighted the roles for oxidative stress and mitochondrial dysfunction pathways. Functional analyses of these networks provided evidence for activation of transforming growth factor beta (TGFβ) signaling in ROP-Os/+ kidneys despite similar expression of the TGFβ ligand between the tested strains. Conclusions These data demonstrate the complex dysregulation of normal cellular functions in this animal model of FSGS and suggest that therapies directed at multiple levels will be needed to effectively treat human kidney diseases.http://deepblue.lib.umich.edu/bitstream/2027.42/112491/1/12882_2011_Article_362.pd

Understanding lower limb location-specific running-related pain by males and females

Running-related injuries (RRIs) have been attributed to a number of factors, but there is no consensus in the current literature as to whether sex is a risk factor for RRIs, or if risk factors for running-related pain differ by sex. It has been suggested that due to differences in anatomy and biomechanics, males and females have their own RRI risk profiles; several variables may need to be taken into consideration when assessing sex as a risk factor for RRIs and running-related pain. Purpose: The proposed study represented the first two phases of a three-tiered epidemiological project. The purpose of Phase I was to determine whether there were significant differences in site-specific running-related injuries/pain between males and females training for a 10-km race; a statistical model was then created in the second phase to determine what explains running-related pain in the lower extremity by sex, for runners preparing for a 10-km race. Methods: 114 recreational runners (46 males [37.9 ± 9.8 years; 75.46 ± 9.55 kg; 1.75 ± 0.08 m] and 68 females [32.60 ± 8.70 years; 63.47 ± 9.96 kg; 1.66 ± 0.06 m]) took part in a prospective cohort design of a gradual 12-week training program, and a comprehensive baseline assessment was recorded for each participant. Weekly online surveys were administered to monitor whether subjects experienced an RRI. The Visual Analogue Scale (VAS) was administered to record pain scores at 11 relevant anatomical locations in the lower limb and the whole body, at baseline and during Weeks 4, 8, and 12 of the program. Foot and Ankle Disability Index (FADI) pain scores were also measured at these time points. Results: Sex was not a significant factor in the onset of location-specific, running-related pain in the VAS sites, but significant main effects of sex were found for the FADI. Males and females had different explanatory variables for each of the VAS and FADI sites. Conclusions: The causes of running-related pain in the individual anatomical regions varied by sex, which suggests that running-related pain may be decreased by addressing sex-specific risk factors.Education, Faculty ofKinesiology, School ofGraduat

Identification of nephropathy candidate genes by comparing sclerosis-prone and sclerosis-resistant mouse strain kidney transcriptomes

Abstract Background The genetic architecture responsible for chronic kidney disease (CKD) remains incompletely described. The Oligosyndactyly (Os) mouse models focal and segmental glomerulosclerosis (FSGS), which is associated with reduced nephron number caused by the Os mutation. The Os mutation leads to FSGS in multiple strains including the ROP-Os/+. However, on the C57Bl/6J background the mutation does not cause FSGS, although nephron number in these mice are equivalent to those in ROP-Os/+ mice. We exploited this phenotypic variation to identify genes that potentially contribute to glomerulosclerosis. Methods To identify such novel genes, which regulate susceptibility or resistance to renal disease progression, we generated and compared the renal transcriptomes using serial analysis of gene expression (SAGE) from the sclerosis-prone ROP-Os/+ and sclerosis resistant C57-Os/+ mouse kidneys. We confirmed the validity of the differential gene expression using multiple approaches. We also used an Ingenuity Pathway Analysis engine to assemble differentially regulated molecular networks. Cell culture techniques were employed to confirm functional relevance of selected genes. Results A comparative analysis of the kidney transcriptomes revealed multiple genes, with expression levels that were statistically different. These novel, candidate, renal disease susceptibility/resistance genes included neuropilin2 (Nrp2), glutathione-S-transferase theta (Gstt1) and itchy (Itch). Of 34 genes with the most robust statistical difference in expression levels between ROP-Os/+ and C57-Os/+ mice, 13 and 3 transcripts localized to glomerular and tubulointerstitial compartments, respectively, from micro-dissected human FSGS biopsies. Network analysis of all significantly differentially expressed genes identified 13 connectivity networks. The most highly scored network highlighted the roles for oxidative stress and mitochondrial dysfunction pathways. Functional analyses of these networks provided evidence for activation of transforming growth factor beta (TGFβ) signaling in ROP-Os/+ kidneys despite similar expression of the TGFβ ligand between the tested strains. Conclusions These data demonstrate the complex dysregulation of normal cellular functions in this animal model of FSGS and suggest that therapies directed at multiple levels will be needed to effectively treat human kidney diseases.</p