As a basic scientist for last 30 years, I am involved in understanding the pathophysiology of the glomerular filtration barrier function. Glomerular filtration barrier is a unique in structure that plays critical role in controlling micro and macromolecular permeability. I developed an in vitro assay to study the glomerular filtration barrier function. Using this method, we studied the direct effect of various biological agents including reactive oxygen species, matrix degrading metalloproteases, platelet activating factor and various cytokines (TNF-α, TGF-β) on glomerular filtration barrier function. Using this method, we are involved in identifying the putative causative factor for the recurrent focal segmental glomerulosclerosis (FSGS) and mechanisms of nephrotic syndrome.