Trpm7 Protein Contributes to Intercellular Junction Formation in Mouse Urothelium

Area of Science:

• Urology
• Cell Biology
• Physiology

Background:

• Transient Receptor Potential Melastatin 7 (Trpm7) is a channel permeable to divalent cations.
• Trpm7 is implicated in magnesium homeostasis, cellular adhesion, and migration.
• The in vivo function of Trpm7 in the urothelium remains largely uncharacterized.

Purpose of the Study:

• To investigate the role of Trpm7 in mouse urothelium in vivo.
• To determine the effects of Trpm7 knockout on bladder function and physiology.

Main Methods:

• Generation of urothelium-specific Trpm7 knockout (KO) mice using tamoxifen induction.
• Patch clamp recordings in primary urothelial cells to assess cation currents.
• Evaluation of voiding behavior, bladder histology, cytokine expression, and transmission electron microscopy.

Main Results:

• Trpm7 KO urothelial cells exhibited reduced Mg(2+)-inhibitable and acid-inducible cation currents.
• Trpm7 KO mice displayed significantly smaller voided volumes and submucosal edema.
• Increased expression of pro-inflammatory cytokines (TNF-α, IL-1β) and immature intercellular junctions were observed in Trpm7 KO bladders.

Conclusions:

• Trpm7 plays a critical role in the formation and maintenance of intercellular junctions in mouse urothelium.
• Disruption of Trpm7 leads to impaired barrier function, inflammation, and potentially altered bladder afferent nerve activity.
• These findings suggest Trpm7 is a key regulator of urothelial integrity and voiding behavior.