research

We are a diverse team of engineers, nephrologists, cell biologists and biochemists. As such, research in SBL is exceptionally multidisciplinary, covering a range of projects from basic cell biology to biomedical informatics and many things in between. Our research is funded through multiple grants from the NIH, Department of the Army as well as other non-profit, private and industry sources. If you would like to support our research program, you can donate by clicking on this link and specifying under other “Azeloglu Lab, Division of Nephrology”.

Cytoskeletal Mechanobiology

Hypertension is the second leading cause of kidney failure in the United States. It has a strong association with disease progression in both podocytopathies and polycystic kidney disease. Terminally differentiated kidney podocytes are thought to be irreversibly injured during the high biomechanical stress states imposed by hypertension. It is still not clearly understood how biomechanical forces are mechanistically linked to cystogenesis. Our lab studies both of these tissue systems using a combination of systems biology approaches. We hypothesize that a specialized mechano-responsive actin cytoskeleton is responsible for maintaining the necessary structural integrity of podocyte foot processes. Using animal models of podocytopathies, we have identified several key proteins of the actin cytoskeleton that were previously not known to be expressed in podocytes. We use single-cell transcriptomics, high-content imaging and computational modeling of upstream signaling pathways to understand the dynamics of regulatory networks that control the expression of these novel gene products, and to study the spatiotemporal organization of key components within the specialized actin cytoskeleton in podocytes. Our recent publication in Journal of American Society of Nephrology outlines the discovery of such a cytoskeletal regulator, LIM-nebulette.  

Systems Biomechanics

How the interaction of physical forces and biochemical processes affects basic cell biology still eludes most scientists. We study systems-level regulation of cell and tissue biomechanics to understand its role in progression of complex diseases, and to discover new drug targets and to design novel therapeutic strategies based on mechanobiological principles. We are specifically interested in proteins that form the focal adhesion complex and actin-associated proteins that shape the mechanobiological information processing capacity of the cell. In addition to playing critical structural roles, these crosslinking and adapter proteins modulate mechanotransduction through spatial segregation of signaling proteins. We use proteomics to identify key functional proteins within the cytoskeleton or the adhesome and utilize classical cell biological as well as bioengineering methods to characterize the complex role they play in pathophysiology. We have recently showed how multiple nested network motifs controlled expression and localization of the actin-crosslinking protein, synaptopodin, in kidney podocytes. Our findings have been featured as the cover story on Science Signaling.

Kidney Tissue Engineering

We combine nanotechnology, functional tissue engineering, and multiple-omics methodologies to study kidney biology and glomerular disease mechanisms. Despite the functional importance of their specialized morphology, isolated glomerular epithelial cells, or podocytes, do not exhibit any geometric hallmarks of their in situ morphology. We use innovative microfabrication techniques to construct long-term culture substrates that induce morphological remodeling of kidney podocytes into arborized, or branched, shapes. This geometric remodeling leads to functional specialization of peripheral projections where filtration proteins are translocated into the periphery of the cell. This phenomenon cannot be observed in immortalized podocytes cultured on regular, or unpatterned, surfaces. This phenotypic specialization can be used as a proxy for podocyte differentiation, which enabled us to develop a kidney-on-chip platform. Using induced pluripotent stem cells (iPSCs) to generate adult human podocoytes, we developed a high-content screening system that utilizes microengineered surfaces to quantitatively characterize cytoskeletal and biomechanical drug responses in kidney podocytes.

Biophysical Mechanisms of Nephrotoxicity

We are investigating the molecular, structural, and subcellular determinants of chemotherapy-induced podocyte damage and nephrotoxicity. Using retroactive analyses of the FDA Adverse Events Reporting System, we identify clinically used tyrosine kinase inhibitors (TKIs) that are associated with glomerular dysfunction and proteinuria. Using high-content imaging, atomic force microscope elastography, and phosphoproteomics, we identify molecular, morphological and biophysical signatures of nephrotoxicity induced by oncological TKIs. Our integrative modeling studies point to key hubs within the human kinome that are targeted by these TKIs, which then negatively impact podocyte biophysics and renal function. We are searching for potential upstream interaction nodes that can be targeted for mitigation of nephrotoxic adverse effects of oncological drugs. Our manuscript in Nature Communications has uncovered a direct link between cellular mechanobiology and the BCR-ABL inhibitor dasatinib.