TNF inhibits AQP2 expression via a miR137-dependent pathway

Area of Science:

• Renal physiology
• Molecular biology
• Immunology

Background:

• Tumor necrosis factor (TNF) is known to inhibit extrarenal aquaporin (AQP) expression.
• MicroRNA-137 (miR-137) is a regulator of aquaporin-2 (AQP2) expression.
• The interaction between TNF, miR-137, and AQP2 in the kidney remains unclear.

Purpose of the Study:

• To investigate if TNF inhibits renal AQP2 expression via a miR-137-dependent mechanism.
• To elucidate the role of TNF and miR-137 in regulating kidney water and electrolyte balance.

Main Methods:

• Primary renal inner medullary collecting duct (IMCD) cells were used for in vitro experiments.
• Techniques included miRNA mimic transfection, TNF silencing via lentivirus, and exposure to hypertonic medium.
• In vivo studies involved intrarenal lentivirus silencing of TNF in mice and measurement of urine parameters.

Main Results:

• miR-137 directly targets and decreases AQP2 mRNA and protein expression in IMCD cells.
• Hypertonic conditions increased both miR-137 and TNF expression in IMCD cells.
• TNF upregulates miR-137 expression, and silencing TNF increased AQP2 levels and affected kidney diluting ability.

Conclusions:

• TNF inhibits renal AQP2 expression through a miR-137-dependent mechanism.
• This pathway plays a role in regulating kidney function, electrolyte balance, and potentially blood pressure.
• Cytokines like TNF are emerging as key mediators in physiological responses beyond inflammation.