Doxorubicin In Vivo Rapidly Alters Expression and Translation of Myocardial Electron Transport Chain Genes, Leads to ATP Loss and Caspase 3 Activation

Background: Doxorubicin is one of the most effective anti-cancer drugs but its use is limited by cumulative cardiotoxicity that restricts lifetime dose. Redox damage is one of the most accepted mechanisms of toxicity, but not fully substantiated. Moreover doxorubicin is not an efficient redox cycling compound due to its low redox potential. Here we used genomic and chemical systems approaches in vivo to investigate the mechanisms of doxorubicin cardiotoxicity, and specifically test the hypothesis of redox cycling mediated cardiotoxicity.

Association analysis of Notch pathway signalling genes in diabetic nephropathy

Several studies have provided compelling evidence implicating the Notch signalling pathway in diabetic nephropathy. Co-regulation of Notch signalling pathway genes with GREM1 has recently been demonstrated and several genes involved in the Notch pathway are differentially expressed in kidney biopsies from individuals with diabetic nephropathy. We assessed single-nucleotide polymorphisms (SNPs; n = 42) in four of these key genes (JAG1, HES1, NOTCH3 and ADAM10) for association with diabetic nephropathy using a case-control design.
Tag SNPs and potentially functional SNPs were genotyped using Sequenom or Taqman technologies in a total of 1371 individuals with type 1 diabetes (668 patients with nephropathy and 703 controls without nephropathy). Patients and controls were white and recruited from the UK and Ireland. Association analyses were performed using PLINK (http://pngu.mgh.harvard.edu/similar to purcell/plink/) and haplotype frequencies in patients and controls were compared. Adjustment for multiple testing was performed by permutation testing.
In analyses stratified by centre, we identified six SNPs, rs8708 and rs11699674 (JAG1), rs10423702 and rs1548555 (NOTCH3), rs2054096 and rs8027998 (ADAM10) as being associated with diabetic nephropathy before, but not after, adjustment for multiple testing. Haplotype and subgroup analysis according to duration of diabetes also failed to find an association with diabetic nephropathy.
Our results suggest that common variants in JAG1, HES1, NOTCH3 and ADAM10 are not strongly associated with diabetic nephropathy in type 1 diabetes among white individuals. Our findings, however, cannot entirely exclude these genes from involvement in the pathogenesis of diabetic nephropathy.

Harnessing naturally randomized transcription to infer regulatory relationships among genes

We develop an approach utilizing randomized genotypes to rigorously infer causal regulatory relationships among genes at the transcriptional level, based on experiments in which genotyping and expression profiling are performed. This approach can be used to build transcriptional regulatory networks and to identify putative regulators of genes. We apply the method to an experiment in yeast, in which genes known to be in the same processes and functions are recovered in the resulting transcriptional regulatory network.

Differences in mouse models of diabetes mellitus in studies of male reproduction

Diabetes Mellitus (DM) has been found to have subtle yet profound effects on the metabolic status of the testis, the expression of numerous spermatogenic genes and is associated with increased numbers of sperm with nuclear DNA damage. The precise mechanism causing these detrimental effects remains unknown. The presence of increased levels of the most prominent member (carboxymethyllysine - CML) of the advanced glycation end product adducts and their receptor (RAGE) in the reproductive tract of DM men has provided a new avenue for research. As there are suspicions that the antibiotic (streptozotocin - STZ) employed to induce DM is also capable of causing oxidative stress and DNA damage, we compared CML and RAGE levels in the reproductive tract and sperm nDNA status of STZ mice with the levels in the Ins(2Akita) mouse to determine which more closely mimics the situation described in the human diabetic. CML was observed in the testes, epididymes and sperm of all animals. Sperm from DM mice showed particularly strong CML immunolocalization in the acrosomal cap, the equatorial region and whenever present, cytoplasmic droplets. Although increased, the level of CML on the sperm of the STZ and Ins(2Akita) DM mice did not reach statistical significance. RAGE was present on the developing acrosome and epididymal sperm of all animals and in discrete regions of the epididymes of the DM models. Only the epididymal sperm of the Ins(2Akita) mice were found to have significantly increased (p < 0.0001) nDNA damage. The Ins(2Akita) mouse therefore appears to more accurately reflect the conditions found in the human and, as such, is a more representative model for the study of diabetes and glycation's influence on male fertility.

Investigation of ACE, ACE2 and AGTR1 genes for association with nephropathy in Type 1 diabetes mellitus

Background Polymorphisms in ACE and AGTR1 genes have been assessed in multiple studies for association with diabetic nephropathy; however, results are conflicting. The ACE2 gene has not been studied extensively for association with diabetic nephropathy.

Resequencing of the CCL5 and CCR5 genes and investigation of variants for association with diabetic nephropathy

Chemokine (C-C motif) ligand 5 (CCL5) and chemokine (C-C motif) receptor 5 are implicated in the pathogenesis of diabetic nephropathy (DN). We hypothesize that variants in these genes may be associated with DN. The CCL5 and chemokine receptor type 5 (CCR5) genes were resequenced, variants identified (n=58), allele frequencies determined in 46 individuals (92 chromosomes) and efficient haplotype tag single-nucleotide polymorphisms (htSNPs) selected to effectively evaluate the common variation in these genes. One reportedly functional gene variant and eight htSNPs were genotyped in a case-control association study involving Caucasian individuals with type 1 diabetes (267 cases with DN and 442 non-nephropathic diabetic controls). Genotyping was performed using MassARRAY iPLEX, TaqMan, gel electrophoresis and direct capillary sequencing. After correction for multiple testing, there were no statistically significant associations between variants in the CCL5 and CCR5 genes and DN. Journal of Human Genetics (2010) 55, 248-251; doi:10.1038/jhg.2010.15; published online 5 March 2010