Project Summary/Abstract The goal of this proposal is to develop and validate two tools for in situ analysis of epigenetic state and chromatin organization in single cells in kidney tissue. The first tool is based on our recently developed technology SCEPTRE (Single-Cell Evaluation of Post TRanslational Epigenetic encoding) established for cultured cells that will be adapted for use with kidney tissues in order to directly resolve and quantify histone modifications at specific DNA loci in situ in single cells. The second tool is a new method called APT-FISH (Amplified Probes from Tagmentation Fluorescence in situ Hybridization) that is designed to profile changes to open chromatin. Each of these tools will be used concurrently with super-resolution expansion microscopy imaging in order to directly relate nanoscale renal physiology to chromatin or epigenetic state and they will be applied to the study of aging and senescence in kidney tissue.