Congenital anomalies of the kidneys and urinary tracts (CAKUT) constitute approximately 20 to 30% of all identified birth defects. CAKUTs are the most common cause of pediatric chronic kidney disease (CKD). Although genetic disorders play a major role in CAKUT, approximately 70% of all congenital diseases cannot directly be linked to a specific genetic mutation. In such cases, environmental factors play an important role in manifestation of these anomalies. During kidney development, the ureteric bud (UB) undergoes repeated rounds of branching and simultaneously induces the metanephric mesenchyme to form preliminary nephrons around its UB branch tips. This fundamental process, called branching morphogenesis, establishes a spatial architecture of the mature kidney and urinary tract. Any disturbances in this process, caused by maternal/fetal exposure to teratogens and environmental toxicants, leads to the spectrum of abnormalities in CAKUT. Studying the impact of potential teratogens on developing kidneys is challenging due to obstacles in obtaining a substantial number of embryonic kidneys and difficulties in ex vivo culturing. In vitro models that mimic kidney development are essential to provide better insights in disease modeling. UB organoids, characterized by their tree-like tubular structures, accurately mimic the branching morphogenesis and spatial architecture of the kidney. Current UB organoid models have some challenges that hamper their widespread application. In the following, we highlight our approach to overcome them:
• Our project aims at the development of a commercial microfluidic platform, which is easy to use even in non-specialized laboratories. The DOMES product provide a new toolbox to position in vitro UB models in specific confinements and to expose them to biochemical and biophysical factors in a controlled manner. This unique approach proves advantageous for the medium- to high-throughput quantification of image-based parameters such as whole-organoid morphology and growth rate.
• Our novel in vitro model for kidney branching morphogenesis fabricated from thin, transparent polymer films enabling high-resolution imaging and a real-time assessment of the effect of chemicals on this intricate process.
• Current UB organoid models rely on conventional static cultures, with regular media exchanges performed manually by researchers. Unlike in vivo, where the flow of both nutrients and teratogens is constant in flow, static cultures cannot mimic the fluctuating exposure of in vitro UB organoids to possible chemical compounds. To address this challenge, we established a microfluidic platform for a continuous and active delivery of soluble factors, which also facilitates the administration of drugs with a short half-life.
Objectives
The overall aim is screening of ureteric bud related teratogens with four main objectives:
Objective 1. Design and fabrication of a microfluidic DOMES product family to position budding and branching UB organoids in microporous compartments
Objective 2. Development of a reliable protocol to generate PSCs-derived ureteric bud organoids in the porous compartments (milliwells) of the DOMES product family
Objective 3. Assess the influence of a small library of chemical compounds on UB branching morphogenesis
Objective 4. Development of a microphysiological DOMES system which enables the dynamic culture and control of local concentrations of soluble factors
