Kidney Week

Abstract: TH-PO0043

Spatial Reorganization of WNK Signaling During Chronic Furosemide-Induced Distal Tubule Remodeling

Session Information

• Fluid, Electrolyte, and Acid-Base Disorders: Basic Research
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Fluid, Electrolytes, and Acid-Base Disorders

• 1101 Fluid, Electrolyte, and Acid-Base Disorders: Basic

Authors

• Gutiérrez Gallardo, Miguel Ángel, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Miguel Ángel Gutiérrez Gallardo, MD

• Said, J. Emilio, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

J. Emilio Said, MD

• Marquina Castillo, Brenda N., Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Brenda N. Marquina Castillo, PhD

• Rivera Garcia, Guadalupe, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Guadalupe Rivera Garcia, MEd

• Castañeda-Bueno, Maria, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Maria Castañeda-Bueno, PhD

• Gamba, Gerardo, Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran, Mexico City, CDMX, Mexico

Gerardo Gamba, MD, PhD

Background

Chronic loop diuretic treatment induces adaptive salt reabsorption in distal nephron segments and contributes to diuretic resistance. The trigger is not known. Because chronic furosemide exposure is accompanied by hypokalemia, it is not known whether the trigger for distal convoluted tubule (DCT) and WNK signaling is hypokalemia or increased salt delivery. We hypothesized that hypokalemia is not required for the chronic furosemide treatment to induce coordinated molecular and structural adaptations in the DCT, characterized by WNK body formation and distal tubular remodeling.

Methods

14-week-old male C57BL/6 mice were distributed into one control group and two experimental groups receiving furosemide (90 mg/kg/day) for either 1 or 2 weeks. To minimize volume depletion and prevent hypokalemia, mice were supplemented with 0.8% NaCl and 0.2% KCl throughout the treatment period. Mice were placed in metabolic cages for urine collection and urinary electrolyte measurements, and blood samples were obtained for assessment of plasma electrolytes. Kidneys were harvested for analysis by immunoblotting and immunofluorescence.

Results

The western blot analysis revealed that furosemide treatment increased the total and phosphorylated NCC, despite the absence of hypokalemia, consistent with enhanced distal salt reabsorption. Sall3 abundance was also increased, suggesting DCT lineage expansion. Renal immunofluorescence showed that the number of NCC-positive tubules increased and were positive for Ki-67 and PCNA, consistent with DCT hyperplasia. WNK/SPAK-positive puncta consistent with WNK bodies appeared after 1 week, predominantly in CNT, and became prominent throughout DCT/CNT after 2 weeks, suggesting progressive spatial reorganization of WNK signaling during distal remodeling.

Conclusion

Chronic furosemide treatment induces distal nephron remodeling and progressive spatial reorganization of WNK signaling. These changes occurred in the absence of hypokalemia. Our findings support a role for WNK bodies in adaptive distal tubular plasticity during chronic loop diuretic exposure and suggest that increased delivery is the trigger for the DCT adaptive remodeling during chronic inhibition of the salt reabsorption by the thick ascending limb.

Acknowledgment

This work is funded by grant No. IN203025 from DGAPA/UNAM and CBF-2025-I-196 from SECITHI

Funding

• Government Support – Non-U.S.