Urine exosomes from healthy and hypertensive pregnancies display elevated level of α-subunit and cleaved α- and γ-subunits of the epithelial sodium channel—ENaC

Autor: Rikke Ydegaard, Boye L. Jensen, Maria Ravn Nielsen, Mie R. Hansen, Per Svenningsen, Rikke Zachar, Jan Stener Jørgensen, Britta Frederiksen-Møller, Kristian B Buhl
Rok vydání: 2017
Předmět:
Zdroj: Nielsen, M R, Frederiksen-Møller, B, Langkilde, R Z, Jørgensen, J S, Rytz, M, Ydegaard, R, Svenningsen, P, Buhl, K B & Jensen, B L 2017, ' Urine exosomes from healthy and hypertensive pregnancies display elevated level of-α-subunit and cleaved-α-and γ-subunits of the epithelial sodium channel--ENaC ', Pflügers Archiv-European Journal of Physiology, vol. 469, no. 9, pp. 1107–1119 . https://doi.org/10.1007/s00424-017-1977-z
ISSN: 1432-2013
0031-6768
DOI: 10.1007/s00424-017-1977-z
Popis: Preeclampsia is characterized by hypertension, proteinuria, suppression of plasma renin-angiotensin-aldosterone, and impaired urine sodium excretion. Aberrantly filtered plasmin in urine may activate proteolytically the γ-subunit of the epithelial sodium channel (ENaC) and promote Na+ reabsorption and urine K+ loss. Plasma and urine was sampled from patients with preeclampsia, healthy pregnant controls and non-pregnant women, and from patients with nephrostomy catheters. Aldosterone concentration, urine plasminogen, and protein were determined. Exosomes were isolated by ultracentrifugation. Immunoblotting was used to detect exosome markers; γ-ENaC (two different epitopes within the inhibitory peptide tract), α-ENaC, and renal outer medullary K-channel (ROMK) and compared with human kidney cortex homogenate. Urine total plasmin(ogen) was significantly increased in preeclampsia, plasma and urine aldosterone was higher in pregnancy compared to non-pregnancy, and the urine Na/K ratio was lower in preeclampsia compared to healthy pregnancy. Exosome markers ALIX and AQP-2 were stably associated with exosomes across groups. Exosomal α-ENaC-subunit migrated at 75 kDa and dominantly at 50 kDa and was significantly elevated in pregnancy. In human kidney cortex tissue and two of four pelvis catheter urine, ~90-100 kDa full-length γ-ENaC was detected while no full-length γ-ENaC but 75, 60, and 37 kDa variants dominated in voided urine exosomes. There was no difference in γ-ENaC protein abundances between healthy pregnancy and preeclampsia. ROMK was detected inconsistently in urine exosomes. Pregnancy and preeclampsia were associated with increased abundance of furin-cleaved α-ENaC subunit while γ-subunit appeared predominantly in cleaved form independently of conditions and with a significant contribution from post-renal cleavage.
Databáze: OpenAIRE
Externí odkaz: