Evaluation of the transcript level of the genes ITGA3 and ITGB1 after albumin overload in podocytes in vitro

Abstract

The presence of persistent proteinuria is the main sign of glomerular disease and development of chronic kidney disease (CKD) being an important prognostic marker for this condition. In glomerular injury, the main protein present in the urine is albumin. In this case, albuminuria results from impairment of the glomerular filtration barrier, which may be associated with podocyte injury. Podocytes are highly specialized and differentiated cells, whose extensions, the foot processes, are extremely important in the filtration process and are divided into three domains: apical membrane domain (AMD), slit diaphragm (SD) and basal membrane domain (BMD). Damage to any of the domains leads to a characteristic response, foot process effacement, which leads to progressive albuminuria. However, there are still controversies in the literature regarding the impact of proteinuria for the worsening of foot process effacement in podocytopathies. There are a few studies in the literature evaluating the impact of albumin overload on podocyte cell culture in vitro, which demonstrated alterations in pathways related to inflammation, reticulum stress, apoptosis, proliferation, cell differentiation and cytoskeletal rearrangement. Despite having achieved good results, they still do not definitively clarify the molecular consequences of albumin overload. There are no studies evaluating the expression and adhesion of ±3²1 integrin, encoded by the ITGA3 and ITGB1 genes - a fundamental protein for signaling and integration of the basal domain with the podocyte cytoskeleton - after albumin overload in podocytes in vitro. Therefore, the objective of the present study is to evaluate whether there is a difference in the transcription rate of the ITGA3 and ITGB1 genes in face of progressive albumin overload in podocytes in vitro, without and with previous exposure to the nephrotoxic drug puromycin aminoglycoside (PAN), as well as to evaluate the adhesion of podocytes under the same conditions. If the expression is altered after albumin overload, we will perform regression of overload to verify if the phenotype is recovered. It is important to point out that the advancement of knowledge of specific molecular pathways could allow the identification of potential therapeutic targets for general or specific conditions. If successful, such future studies could propose the use of interventions capable of minimizing the deleterious renal effects of albumin, contributing to the deceleration of CKD progression in many patients.(AU)