Transcriptional profiling identifies TNS4 function in epithelial tubulogenesis

Area of Science:

• Cell Biology
• Molecular Biology
• Developmental Biology

Background:

• Hepatocyte growth factor (HGF) is vital for tubulogenesis and metastasis.
• Understanding tubulogenesis requires identifying genes involved in its intermediate phases.
• Previous methods for gene identification were hindered by inefficient and asynchronous tubule formation.

Purpose of the Study:

• To develop a synchronous and efficient tubulogenesis system.
• To identify genes temporally regulated during tubulogenesis using time-course transcriptional profiling.
• To elucidate the role of tensin 4 (TNS4) and its interaction with STAT3 in tubulogenesis and epithelial invasion.

Main Methods:

• Developed a synchronous, efficient tubulogenesis system using Madin-Darby canine kidney (MDCK) cells.
• Performed time-course transcriptional profiling to identify differentially expressed genes.
• Utilized gene knockdown (KD) and exogenous expression to assess gene function.
• Investigated the impact of TNS4 mutations and STAT3 activation on tubulogenesis.

Main Results:

• Identified tensin 4 (TNS4) as a highly upregulated gene during tubulogenesis.
• Knockdown of TNS4 decreased the formation of extensions and tubules.
• Exogenous TNS4 expression marked invasive cells in epithelial sheets.
• A mutation in the TNS4 SH2 domain impaired the transition to invasive migration and increased STAT3 activation.
• Constitutively active STAT3 mimicked the observed defect.

Conclusions:

• The study established a robust system for synchronous tubulogenesis, enabling gene discovery.
• Tensin 4 (TNS4) plays a critical role in epithelial sheet invasion and tubule formation.
• The TNS4-STAT3 signaling axis is a key regulator of these developmental processes.