Light- and electron-microscopic evaluation of renal tubular cell vacuolation induced by administration of nitrilotriacetate or sucrose

Merski, Jerome A.; Meyers, Marta

doi:10.1016/0278-6915(85)90109-7

Cited by 16 publications

(5 citation statements)

References 17 publications

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“…2 Instead of the characteristic V-type ATPasepositive vesicles, we observed atypical vesicular structures reminiscent of cell vacuolation in A-ICs of knockin mice, which can occur in response to different types of stress. 22 Notably, the accumulation of intracellular p62-and ubiquitin-positive structures in A-ICs of Ae1 +/R607H and Ae1 R607H/R607H mice suggests a defect in the degradative pathway and/or in autophagy, 23 which may be related to defective lysosomal targeting of the V-type ATPase. Notably, impaired V-type ATPase activity because of inactivation of the renal (pro)renin receptor also resulted in multilamellar bodies and defects in autophagy.…”

Section: Discussionmentioning

confidence: 99%

Intercalated Cell Depletion and Vacuolar H+-ATPase Mistargeting in an Ae1 R607H Knockin Model

Mumtaz¹,

Trepiccione²,

Hennings³

et al. 2016

JASN

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Distal nephron acid secretion is mediated by highly specialized type A intercalated cells (A-ICs), which contain vacuolar H-ATPase (V-type ATPase)-rich vesicles that fuse with the apical plasma membrane on demand. Intracellular bicarbonate generated by luminal H secretion is removed by the basolateral anion-exchanger AE1. Chronically reduced renal acid excretion in distal renal tubular acidosis (dRTA) may lead to nephrocalcinosis and renal failure. Studies in MDCK monolayers led to the proposal of a dominant-negative trafficking mechanism to explain AE1-associated dominant dRTA. To test this hypothesis , we generated an Ae1 R607H knockin mouse, which corresponds to the most common dominant dRTA mutation in human AE1, R589H. Compared with wild-type mice, heterozygous and homozygous R607H knockin mice displayed incomplete dRTA characterized by compensatory upregulation of the Na/HCO cotransporter NBCn1. Red blood cell Ae1-mediated anion-exchange activity and surface polypeptide expression did not change. Mutant mice expressed far less Ae1 in A-ICs, but basolateral targeting of the mutant protein was preserved. Notably, mutant mice also exhibited reduced expression of V-type ATPase and compromised targeting of this proton pump to the plasma membrane upon acid challenge. Accumulation of p62- and ubiquitin-positive material in A-ICs of knockin mice suggested a defect in the degradative pathway, which may explain the observed loss of A-ICs. R607H knockin did not affect type B intercalated cells. We propose that reduced basolateral anion-exchange activity in A-ICs inhibits trafficking and regulation of V-type ATPase, compromising luminal H secretion and possibly lysosomal acidification.

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Section: Discussionmentioning

confidence: 99%

Intercalated Cell Depletion and Vacuolar H+-ATPase Mistargeting in an Ae1 R607H Knockin Model

Mumtaz¹,

Trepiccione²,

Hennings³

et al. 2016

JASN

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“…Given that they also become sequestered in high concentrations within the lysosomal compartment, then a simultaneous osmotic effect can occur leading to visible dilation of the lysosome. Similar osmotic vacuolation in the renal tubule epithelium occurs with other hydrophilic compounds such as sugars 12 and pegylated proteins. 13 In the case of ASO-related renal vacuolation, it was found to be abolished by employing more rapid fixation by perfusion with modified Karnovsky's fixative.…”

Section: Fixation Effectsmentioning

confidence: 74%

Antisense Oligonucleotide-Related Macrovesicular Vacuolation of Hippocampal Neurons in Nonhuman Primates

et al. 2022

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2′-methoxyethyl (MOE) antisense oligonucleotides (ASOs) tested in multidose intrathecal nonhuman primate (NHP) toxicity studies have consistently revealed the presence of single large vacuoles in pyramidal neurons of the hippocampus in the absence of any cellular response. Termed “macrovesicular,” these vacuoles were characterized by immunohistochemistry and transmission electron microscopy which showed that these vacuoles are dilated lysosomes in neurons containing accumulated ASO. Additionally, two NHP studies were conducted to investigate the role of tissue fixation on their histogenesis. In Fixation Study 1, 6 doses of 5 mg 2′-MOE ASO with a full phosphorothioate backbone were administered by lumbar puncture over 5 weeks; in Fixation Study 2, 5 doses of 35 mg 2′-MOE ASO with a mixed phosphorothioate/phosphodiester backbone were administered over 12 weeks. At necropsy in each study, brain slices were either immersion fixed in neutral buffered 10% formalin or Carnoy’s fixative; frozen at −80 °C; or perfusion fixed with modified Karnovsky’s fixative. Fixed samples were processed to paraffin, sectioned, and stained with hematoxylin and eosin (H&E) and compared with H&E cryosections prepared from the frozen tissue of the same brain. The presence of vacuoles in fixed brain tissue but never in fresh frozen tissue showed that they arose during postmortem tissue fixation, and as such represent a processing artifact that is not relevant to human safety assessment of intrathecally administered 2′-MOE ASOs.

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“…The vacuoles did not conform to any known organelles or lipid storage vacuoles. Cellular vacuolization is a known response to various forms of cellular stress 35, 36 and addition of NH 4 Cl to chick fibroblast cells causes reversible vacuolation with no effect on functionality. 36 These authors suggested a mechanism involving sequestration of base left from NH 4 Cl dissociation, to minimise alkalinization of the cytosol.…”

Section: Discussionmentioning

confidence: 99%

Renal peroxiredoxin 6 interacts with anion exchanger 1 and plays a novel role in pH homeostasis

Sorrell

Golder

Johnstone

et al. 2016

Kidney International

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Peroxiredoxin 6 (PRDX6) is one of six members of the PRDX family, which have peroxidase and antioxidant activity. PRDX6 is unique, containing only one conserved cysteine residue (C47) rather than the two found in other PRDXs. A yeast two-hybrid screen found PRDX6 to be a potential binding partner of the C-terminal tail of anion exchanger 1 (AE1), a Cl−/HCO3− exchanger basolaterally expressed in renal α-intercalated cells. PRDX6 immunostaining in human kidney was both cytoplasmic and peripheral and co-localized with AE1. Analysis of native protein showed it was largely monomeric, whereas expressed tagged protein was more dimeric. Two methionine oxidation sites were identified. In vitro and ex vivo pulldowns and immunoprecipitation assays confirmed interaction with AE1, but mutation of the conserved cysteine resulted in loss of interaction. Prdx6 knockout mice had a baseline acidosis with a major respiratory component and greater AE1 expression than wild type animals. After an oral acid challenge, PRDX6 expression increased in wild type mice, with preservation of AE1. However, AE1 expression was significantly decreased in knockout animals. Kidneys from acidified mice showed widespread proximal tubular vacuolation in wild type but not knockout animals. Knockdown of PRDX6 by siRNA in mammalian cells reduced both total and cell membrane AE1 levels. Thus, PRDX6-AE1 interaction contributes to maintenance of AE1 during cellular stress such as during metabolic acidosis.

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Light- and electron-microscopic evaluation of renal tubular cell vacuolation induced by administration of nitrilotriacetate or sucrose

Cited by 16 publications

References 17 publications

Intercalated Cell Depletion and Vacuolar H+-ATPase Mistargeting in an Ae1 R607H Knockin Model

Intercalated Cell Depletion and Vacuolar H+-ATPase Mistargeting in an Ae1 R607H Knockin Model

Antisense Oligonucleotide-Related Macrovesicular Vacuolation of Hippocampal Neurons in Nonhuman Primates

Renal peroxiredoxin 6 interacts with anion exchanger 1 and plays a novel role in pH homeostasis

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