Abstract: TH-PO0058
Endothelial NKCC1 Regulates Lymphatic Contractility and Drainage After Kidney Injury
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
- Zhong, Jianyong, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Yang, Haichun, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Kirabo, Annet, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Shelton, Elaine L., Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Kon, Valentina, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Background
Lymphatic dysfunction has been linked to kidney disease progression, yet the endothelial mechanisms that shape lymphatic pumping and drainage are not well understood. Previously, we showed that pharmacological inhibition of the Na+-K--2Cl- cotransporter, NKCC1, alters lymphatic contractility ex vivo. We now test the in vivo consequences of lymphatic endothelial cell (LEC) NKCC1 on lymphatic dynamics and drainage at baseline and after renal injury.
Methods
We created mice with an inducible, LEC-specific NKCC1 knockdown (KD; NKCC1 flox/flox/Prox1-Cre+) and compared with results wild-type (WT; NKCC1 flox/flox/Prox1-Cre-) controls. Injury was induced by a high-salt diet + uninephrectomy + angiotensin II (AngII) infusion protocol. Lymphatic pumping dynamics were quantified by pressure myography. In vivo lymphatic drainage was assessed by Evans Blue clearance in the ear. Expression of kidney lymphatic endothelial markers was evaluated by RNA analysis. Primary mouse LECs (mLECs) were exposed to the NKCC1 inhibitor, bumetanide (Bumex), to assess viability, migration, tube formation, and transendothelial electrical resistance (TEER).
Results
At baseline, KD mice had higher lymphatic contraction frequency and increased expression of LEC markers compared to WT, whereas Evans Blue clearance was not different between genotypes. After injury, lymphatic contraction frequency increased above baseline in WT, whereas KD lymphatics had reduced frequency of contractions relative to baseline. Injured KD mice had increased ear Evans Blue clearance vs injured WT mice. Mechanistically, lymphatics of injured KD mice were more sensitive to increasing pressure than lymphatics of injured WT mice. Additional NKCC1 inhibition with Bumex caused further reduction in contraction frequency in injured KD lymphatics vs WT, consistent with an additional role for NKCC1 in lymphatic muscle cells driving lymphatic contractility. In vitro, Bumex increased mLEC viability and permeability and inhibited tube formation, without altering migration.
Conclusion
NKCC1 in LECs modulates lymphatic pumping and drainage, particularly after renal injury, identifying the NKCC1 pathway as a novel therapeutic target to modulate lymphatic-driven renal homeostasis following injury.
Funding
- NIDDK Support