Depletion of Cholesterol Reduces ENaC Activity by Decreasing Phosphatidylinositol-4,5-Bisphosphate in Microvilli.
Cell Physiol Biochem
; 47(3): 1051-1059, 2018.
Article
em En
| MEDLINE
| ID: mdl-29843130
ABSTRACT
BACKGROUND/AIMS:
The epithelial sodium channel (ENaC) in cortical collecting duct (CCD) principal cells plays a critical role in regulating systemic blood pressure. We have previously shown that cholesterol (Cho) in the apical cell membrane regulates ENaC; however, the underlying mechanism remains unclear.METHODS:
Patch-clamp technique and confocal microscopy were used to evaluate ENaC activity and density.RESULTS:
Here we show that extraction of membrane Cho with methyl-ß-cyclodextrin (MßCD) significantly reduced amiloride-sensitive current and ENaC single-channel activity. The effects were reproduced by inhibition of Cho synthesis in the cells with lovastatin. We have previously shown that phosphatidylinositol-4,5-bisphosphate (PIP2), an ENaC activator, is predominantly located in the microvilli, a specialized apical membrane domain. Here, our confocal microscopy data show that α-ENaC was co-localized with PIP2 in the microvilli and that Cho was also co-localized with PIP2 in the microvilli. Either extraction of Cho with MßCD or inhibition of Cho synthesis with lovastatin consistently reduced the levels of Cho, PIP2, and ENaC in the microvilli.CONCLUSIONS:
Since PIP2 can directly stimulate ENaC and also affect ENaC trafficking, these data suggest that depletion of Cho reduces ENaC apical density and activity at least in part by decreasing PIP2 in the microvilli.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Colesterol
/
Fosfatidilinositol 4,5-Difosfato
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Canais Epiteliais de Sódio
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Túbulos Renais Coletores
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Microvilosidades
Limite:
Animals
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article