The slit diaphragm, an extracellular extension of the podocyte, is the final filtration barrier, representing an important seal that prevents loss of proteins into the urine . In addition podocytes function as pericytes, counteracting the distending forces of the high pressure perfusion of glomerular capillaries. The podocyte is also thought to play a key role in the constant cleaning of the GBM filter, required to prevent clogging . During development podocytes are derived from the capping mesenchyme, which is induced by the ureteric bud . The earliest differentiating podocytes are detected in the Moreover silencing Bax by stable RNA interference was discovered to minimize the action of sirtuin inhibitors S-shaped bodies, where cells that abut the forming Bowman’s space are seen to express podocyte specific markers, such as MafB. These early podocytes also synthesize Vegf, which initiates the recruitment of endothelial cells into the cleft. Podocytes are also thought to represent sites of initial injury for a number of important kidney diseases, including focal segmental glomerulosclerosis and diabetic nephropathy . Foot process effacement and podocyte loss are among the earliest detected cytologic changes in these diseases. Because of its considerable medical importance the podocyte has been the subject of intense investigation. Of particular relevance to this report, a number of outstanding studies have examined the sets of genes that podocytes express. Some early pioneering work used RT-PCR coupled with laser capture microdissected podocytes, or podocytes harvested from freshly dissected glomeruli, to examine expression levels of restricted numbers of genes in biological samples . Another important study constructed cDNA libraries and cDNA microarrays from isolated glomeruli, and identified podocyte enriched transcripts as well as genes altered in expression in Foxc2 mutants . Podocytes grown in culture have also contributed greatly to our understanding of podocyte biology . Both cDNA and oligonucleotide microarrays have been used to examine changing global gene expression profiles of cultured podocytes exposed to mechanical stress or high glucose levels . Nevertheless, many cellular functions change during culturing of cells, and therefore, results obtained from podocytes in culture need to be interpreted with care .