Mechanism of Renal Cyst Initiation and Progression Through ETV Transcription Factors and Hedgehog Signaling

Renal cysts exist in two categories: non-pathogenic simple cysts and pathogenic malignant cysts. The process of cyst formation can be divided into two stages - initiation and progression. Pathogenic cysts form through continuous initiation and subsequent progression until they reach a malignant state. While numerous genetic and environmental factors have been linked to pathogenic cyst development, the specific mechanisms that differentiate cyst initiation and progression have remained unclear.

In a study using genetic mutation models of ETV transcription factors, specifically ETV1, ETV4, and ETV5, and a hedgehog signaling inhibitor called cyclopamine, researchers have identified a mechanism that regulates both cyst initiation and progression.

By performing a nephron-specific deletion of ETV4 and ETV5, the researchers observed that cyst formation was initiated. However, this initiation did not continue to grow as the animals aged, and only a small number of initial cysts progressed further. To achieve continuous initiation and growth of cysts, additional deletion of ETV1 was required.

Cyclopamine administration was found to suppress the promotion of cyst progression, but had minimal impact on initiating cyst growth. These findings provide clear evidence that the processes of cyst initiation and progression are genetically and molecularly distinct and can be modulated. This new understanding may lead to the development of strategies to control renal cyst initiation and progression, ultimately helping to suppress the growth of pathogenic cysts.