Abstract:The ureteric bud, an outgrowth off the mesonephric duct, interacts with the surrounding metanephric mesenchyme to initiate branching morphogenesis in the developing kidney. In the mature kidney, the ureteric bud and metanephric mesenchyme give rise to the collect ducts and nephrons respectively. Various studies aimed at understanding the role epithelial-mesenchymal interactions play in branching morphogenesis have pinpointed key signaling pathways either directly or indirectly involved. GDNF, FGF, TGF-β, and Wnt signaling pathways regulated by positive and negative feedback loops between the ureteric bud and metanephric mesenchyme have been linked to the formation of arborized geometries and various nephrogenic zones. Not much is known about the role the microenvironment plays in directing branching morphogenesis, cellular differentiation, and cellular organization in the developing kidney. Therefore, this project attempts to further understand how the stiffness of the microenvironment impacts branching morphogenesis and cellular differentiation. An in vitro model using immortalized cells derived from the inner medullary collecting duct were seeded on polyacrilamide gels of varying stiffness and ECM proteins to evaluate cellular differentiation two-dimensionally. Considering that the cells from this experiment were only extracted from the collecting duct, it was crucial to understand the role the nephron progenitor cells play in response to varying stiffness as well. Incorporating nephron progenitor cells allows for the secretion of signaling molecules that interact with collecting duct cells not found in such a specialized and isolated cell line. Therefore, in an attempt to understand cellular organization and differentiation in response to varying stiffness, primary cells were extracted from mice and were then injected into Matrigel of varying percentages to form organoids, resulting in the surprising formation of vasculature. Finally, more representative of an in vivo model, ureteric buds encapsulated by mesenchyme dissected from mice were embedded in varying percentages of Matrigel to evaluate proliferation and differentiation three-dimensionally.
What Does Research Mean To You? I believe research is the primary means through which significant improvements in the healthcare industry can be made. Although many physicians may be implementing techniques aimed at ameliorating a situation at hand, the device or procedure was not, in most cases, developed by these physicians but was rather developed through extensive research. It takes trial after trial, setback after setback, and hours of toiling in the laboratory to see the advancements we see today. As for me, my focus has been on regenerative medicine. Although it may be a relatively new concept, regenerative medicine’s potential is through the roof. The premise of this concept is to offer a patient with end stage organ failure with an alternative to the conventional organ transplant. Whether it be the incredibly long waitlist periods or the potential for immunological rejection resulting in suppressants for life, the organ transplant system is very inefficient. Regenerative medicine allows a patient to culture his or her own “organ” in vitro by means of harvesting his or her own cells. This concept is still in its incipient stages, but remarkable advancements have been made in the past decade. In this field, my primary focus has been on kidney regeneration. Through research, I know that my efforts will eventually impact multiple lives for years to come.
Tell Us Your Journey I began researching during the summer before my freshman year in Dr. David Schmidtke’s laboratory. I primarily focused on kidney regeneration using microfluidic devices through which collecting duct cells were expected to migrate to eventually form renal tubules. In the summer of 2018, I began working in Dr. Victor Varner’s laboratory and worked on establishing ECM protein gradients on Polyacrilamide gels of varying stiffness. The goal of this project was to incorporate iMCD3 collecting duct cells to determine the affinity the cells have for a particular ECM protein at a given stiffness as would be representative in vivo. My focus on kidney regeneration led me to join Dr. Thomas Carroll’s laboratory at UTSW as a Green Fellow in which I focused on branching morphogenesis, ECM protein plating, and organoid formation in response to varying stiffness of the microenvironment.
Advice For Future GreenFellows
In the beginning it may be tough. In more cases than not, you may be the only undergraduate in the lab. Many people will treat you like a grad student and will expect you to perform at that level as well. Don’t forget to ask questions. If you don’t know the reason for doing a specific step in a procedure, ASK! It is more important to know why you are doing what you are doing. This is a learning experience. Success will not happen overnight. It takes trial after trial and failure after failure, but your persistence will lead you to success. Don’t be overwhelmed. Also, and most importantly, don’t forget to take care of yourself. If you have any questions, feel free to email me at [email protected].