Changes in V-ATPase subunits of human urinary exosomes reflect the renal response to acute acid/alkali loading and the defects in distal renal tubular acidosis

Ganesh Pathare, Nasser A. Dhayat, Nilufar Mohebbi, Carsten A. Wagner, Ion A. Bobulescu, Orson W. Moe, Daniel G. Fuster

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

In the kidney, final urinary acidification is achieved by V-ATPases expressed in type A intercalated cells. The B1 subunit of the V-ATPase is required for maximal urinary acidification, while the role of the homologous B2 subunit is less clear. Here we examined the effect of acute acid/alkali loading in humans on B1 and B2 subunit abundance in urinary exosomes in normal individuals and of acid loading in patients with distal renal tubular acidosis (dRTA). Specificities of B1 and B2 subunit antibodies were verified by yeast heterologously expressing human B1 and B2 subunits, and murine wild-type and B1-deleted kidney lysates. Acute ammonium chloride loading elicited systemic acidemia, a drop in urinary pH, and increased urinary ammonium excretion. Nadir urinary pH was achieved at four to five hours, and exosomal B1 abundance was significantly increased at two through six hours after ammonium chloride loading. After acute equimolar sodium bicarbonate loading, blood and urinary pH rose rapidly, with a concomitant reduction of exosomal B1 abundance within two hours, which remained lower throughout the test. In contrast, no change in exosomal B2 abundance was found following acid or alkali loading. In patients with inherited or acquired distal RTA, the urinary B1 subunit was extremely low or undetectable and did not respond to acid loading in urine, whereas no change in B2 subunit was found. Thus, both B1 and B2 subunits of the V-ATPase are detectable in human urinary exosomes, and acid and alkali loading or distal RTA cause changes in the B1 but not B2 subunit abundance in urinary exosomes.

Original languageEnglish (US)
JournalKidney International
DOIs
StateAccepted/In press - Jan 1 2018

Fingerprint

Renal Tubular Acidosis
Exosomes
Alkalies
Adenosine Triphosphatases
Kidney
Acids
Ammonium Chloride
Sodium Bicarbonate
Ammonium Compounds
Yeasts
Urine
Antibodies

Keywords

  • Distal tubule
  • Renal tubular acidosis
  • Urinary exosome

ASJC Scopus subject areas

  • Nephrology

Cite this

Changes in V-ATPase subunits of human urinary exosomes reflect the renal response to acute acid/alkali loading and the defects in distal renal tubular acidosis. / Pathare, Ganesh; Dhayat, Nasser A.; Mohebbi, Nilufar; Wagner, Carsten A.; Bobulescu, Ion A.; Moe, Orson W.; Fuster, Daniel G.

In: Kidney International, 01.01.2018.

Research output: Contribution to journalArticle

Pathare, Ganesh ; Dhayat, Nasser A. ; Mohebbi, Nilufar ; Wagner, Carsten A. ; Bobulescu, Ion A. ; Moe, Orson W. ; Fuster, Daniel G. / Changes in V-ATPase subunits of human urinary exosomes reflect the renal response to acute acid/alkali loading and the defects in distal renal tubular acidosis. In: Kidney International. 2018.
@article{34289b9be4da4176b0b9e6c4f7194b17,
title = "Changes in V-ATPase subunits of human urinary exosomes reflect the renal response to acute acid/alkali loading and the defects in distal renal tubular acidosis",
abstract = "In the kidney, final urinary acidification is achieved by V-ATPases expressed in type A intercalated cells. The B1 subunit of the V-ATPase is required for maximal urinary acidification, while the role of the homologous B2 subunit is less clear. Here we examined the effect of acute acid/alkali loading in humans on B1 and B2 subunit abundance in urinary exosomes in normal individuals and of acid loading in patients with distal renal tubular acidosis (dRTA). Specificities of B1 and B2 subunit antibodies were verified by yeast heterologously expressing human B1 and B2 subunits, and murine wild-type and B1-deleted kidney lysates. Acute ammonium chloride loading elicited systemic acidemia, a drop in urinary pH, and increased urinary ammonium excretion. Nadir urinary pH was achieved at four to five hours, and exosomal B1 abundance was significantly increased at two through six hours after ammonium chloride loading. After acute equimolar sodium bicarbonate loading, blood and urinary pH rose rapidly, with a concomitant reduction of exosomal B1 abundance within two hours, which remained lower throughout the test. In contrast, no change in exosomal B2 abundance was found following acid or alkali loading. In patients with inherited or acquired distal RTA, the urinary B1 subunit was extremely low or undetectable and did not respond to acid loading in urine, whereas no change in B2 subunit was found. Thus, both B1 and B2 subunits of the V-ATPase are detectable in human urinary exosomes, and acid and alkali loading or distal RTA cause changes in the B1 but not B2 subunit abundance in urinary exosomes.",
keywords = "Distal tubule, Renal tubular acidosis, Urinary exosome",
author = "Ganesh Pathare and Dhayat, {Nasser A.} and Nilufar Mohebbi and Wagner, {Carsten A.} and Bobulescu, {Ion A.} and Moe, {Orson W.} and Fuster, {Daniel G.}",
year = "2018",
month = "1",
day = "1",
doi = "10.1016/j.kint.2017.10.018",
language = "English (US)",
journal = "Kidney International",
issn = "0085-2538",
publisher = "Nature Publishing Group",

}

TY - JOUR

T1 - Changes in V-ATPase subunits of human urinary exosomes reflect the renal response to acute acid/alkali loading and the defects in distal renal tubular acidosis

AU - Pathare, Ganesh

AU - Dhayat, Nasser A.

AU - Mohebbi, Nilufar

AU - Wagner, Carsten A.

AU - Bobulescu, Ion A.

AU - Moe, Orson W.

AU - Fuster, Daniel G.

PY - 2018/1/1

Y1 - 2018/1/1

N2 - In the kidney, final urinary acidification is achieved by V-ATPases expressed in type A intercalated cells. The B1 subunit of the V-ATPase is required for maximal urinary acidification, while the role of the homologous B2 subunit is less clear. Here we examined the effect of acute acid/alkali loading in humans on B1 and B2 subunit abundance in urinary exosomes in normal individuals and of acid loading in patients with distal renal tubular acidosis (dRTA). Specificities of B1 and B2 subunit antibodies were verified by yeast heterologously expressing human B1 and B2 subunits, and murine wild-type and B1-deleted kidney lysates. Acute ammonium chloride loading elicited systemic acidemia, a drop in urinary pH, and increased urinary ammonium excretion. Nadir urinary pH was achieved at four to five hours, and exosomal B1 abundance was significantly increased at two through six hours after ammonium chloride loading. After acute equimolar sodium bicarbonate loading, blood and urinary pH rose rapidly, with a concomitant reduction of exosomal B1 abundance within two hours, which remained lower throughout the test. In contrast, no change in exosomal B2 abundance was found following acid or alkali loading. In patients with inherited or acquired distal RTA, the urinary B1 subunit was extremely low or undetectable and did not respond to acid loading in urine, whereas no change in B2 subunit was found. Thus, both B1 and B2 subunits of the V-ATPase are detectable in human urinary exosomes, and acid and alkali loading or distal RTA cause changes in the B1 but not B2 subunit abundance in urinary exosomes.

AB - In the kidney, final urinary acidification is achieved by V-ATPases expressed in type A intercalated cells. The B1 subunit of the V-ATPase is required for maximal urinary acidification, while the role of the homologous B2 subunit is less clear. Here we examined the effect of acute acid/alkali loading in humans on B1 and B2 subunit abundance in urinary exosomes in normal individuals and of acid loading in patients with distal renal tubular acidosis (dRTA). Specificities of B1 and B2 subunit antibodies were verified by yeast heterologously expressing human B1 and B2 subunits, and murine wild-type and B1-deleted kidney lysates. Acute ammonium chloride loading elicited systemic acidemia, a drop in urinary pH, and increased urinary ammonium excretion. Nadir urinary pH was achieved at four to five hours, and exosomal B1 abundance was significantly increased at two through six hours after ammonium chloride loading. After acute equimolar sodium bicarbonate loading, blood and urinary pH rose rapidly, with a concomitant reduction of exosomal B1 abundance within two hours, which remained lower throughout the test. In contrast, no change in exosomal B2 abundance was found following acid or alkali loading. In patients with inherited or acquired distal RTA, the urinary B1 subunit was extremely low or undetectable and did not respond to acid loading in urine, whereas no change in B2 subunit was found. Thus, both B1 and B2 subunits of the V-ATPase are detectable in human urinary exosomes, and acid and alkali loading or distal RTA cause changes in the B1 but not B2 subunit abundance in urinary exosomes.

KW - Distal tubule

KW - Renal tubular acidosis

KW - Urinary exosome

UR - http://www.scopus.com/inward/record.url?scp=85039979582&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85039979582&partnerID=8YFLogxK

U2 - 10.1016/j.kint.2017.10.018

DO - 10.1016/j.kint.2017.10.018

M3 - Article

C2 - 29310826

AN - SCOPUS:85039979582

JO - Kidney International

JF - Kidney International

SN - 0085-2538

ER -