Bioengineering Strategies to Develop Podocyte Culture Systems.

Unraveling the complex behavior of healthy and disease podocytes by analyzing the changes in their unique arrangement of foot processes, slit diaphragm, and the three-dimensional (3D) morphology is a long-standing goal in kidney-glomerular research. The complexities surrounding the podocytes' accessibility in animal models and growing evidence of differences between humans and animal systems have compelled researchers to look for alternate approaches to study podocyte behaviors. With the advent of bioengineered models, an increasingly powerful and diverse set of tools is available to develop novel podocyte culture systems. This review discusses the pertinence of various culture models of podocytes to study podocyte mechanisms in both normal physiology and disease conditions. While no one in vitro system comprehensively recapitulates podocytes' in vivo architecture, we emphasize how the existing systems can be exploited to answer targeted questions on podocyte structure and function. We highlight the distinct advantages and limitations of using these models to study podocyte behaviors and screen therapeutics. Finally, we discuss various considerations and potential engineering strategies for developing next-generation complex 3D culture models for studying podocyte behaviors in vitro. Impact Statement In various glomerular kidney diseases, there are numerous alterations in podocyte structure and function. Yet, many of these disease events and the required targeted therapies remain unknown, resulting in nonspecific treatments. The scientific and clinical communities actively search for new modes to develop structurally and functionally relevant podocyte culture systems to gain insights into various diseases and develop therapeutics. Current in vitro systems help in some ways but are not sufficient. A deeper understanding of these previous approaches is essential to advance the field, and importantly, bioengineering strategies can contribute a unique toolbox to establish next-generation podocyte systems.