Epigenomics in Insulin Resistance Associated Overactive Bladder.

The methylation of cytosines in CpG sites can have profound effects on the ability of genes to be transcribed. To clarify and distinguish the specific methylation changes responsible for overactive bladder (OAB) in those with insulin resistance (IR), the investigator will compare three well-characterized groups of women: 1) OAB and IR; 2) IR only (no OAB); and 3) OAB only (no IR). In this proposal the investigator is only studying women since they are more likely to be affected by OAB with incontinence, the investigator wants to study pure cohorts of patients, and because this is the clinical population cared for by the primary investigator. The plan for future investigations is to apply these findings to broader groups to better understand gender and racial differences.

In Specific Aim 1, the investigator will conduct an epigenome-wide association study (EWAS) study, followed by targeted validation studies to determine whether CpG sites throughout the genome are differentially methylated in well-characterized and matched cohorts, while controlling for the effects of insulin-resistance. In Specific Aim 2, the investigator will assess for differential expression of candidate loci in relation to methylation. RNA-sequencing (RNA-seq) will be used to establish differences in the transcriptome between extreme phenotypes of OAB+IR and OAB alone. The investigator will then use quantitative polymerase chain reaction (qPCR) to validate expression differences in all cohorts, and to confirm differences in candidate loci that are confirmed in experiments from Aim 1. The investigator will proceed with bioinformatic pathway analyses to identify the function and interdependence of genes with altered expression and altered methylation profiles. In Specific Aim 3, the investigator will determine whether expression (mRNA and protein) differences in voided urine cells are also exhibited in biopsied bladder mucosa. The investigator will use targeted assays to confirm similar methylation profiles and gene expression in voided cells and bladder biopsies. The investigator will also compare protein expression of candidate loci such as EXOC6, ZFC3H1, RPS6KA2, and SPON2 proteins, if confirmed in other Aims, between cohorts. When the proposed studies have been completed, it is the expectation that the investigator will have functionally characterized the methylation changes that the investigator preliminarily identified in IR associated OAB.