Paricalcitol attenuates lipopolysaccharide-induced inflammation and apoptosis in proximal tubular cells through the prostaglandin E₂ receptor EP4
Kidney Research and Clinical Practice
; : 145-158, 2017.
Article
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| WPRIM
| ID: wpr-214950
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ABSTRACT
BACKGROUND: Vitamin D is considered to exert a protective effect on various renal diseases but its underlying molecular mechanism remains poorly understood. This study aimed to determine whether paricalcitol attenuates inflammation and apoptosis during lipopolysaccharide (LPS)-induced renal proximal tubular cell injury through the prostaglandin E₂ (PGE₂) receptor EP4. METHODS: Human renal tubular epithelial (HK-2) cells were pretreated with paricalcitol (2 ng/mL) for 1 hour and exposed to LPS (1 μg/mL). The effects of paricalcitol pretreatment in relation to an EP4 blockade using AH-23848 or EP4 small interfering RNA (siRNA) were investigated. RESULTS: The expression of cyclooxygenase-2, PGE₂, and EP4 were significantly increased in LPS-exposed HK-2 cells treated with paricalcitol compared with cells exposed to LPS only. Paricalcitol prevented cell death induced by LPS exposure, and the cotreatment of AH-23848 or EP4 siRNA offset these cell-protective effects. The phosphorylation and nuclear translocation of p65 nuclear factor-kappaB (NF-κB) were decreased and the phosphorylation of Akt was increased in LPS-exposed cells with paricalcitol treatment. AH-23848 or EP4 siRNA inhibited the suppressive effects of paricalcitol on p65 NF-κB nuclear translocation and the activation of Akt. The production of proinflammatory cytokines and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells were attenuated by paricalcitol in LPS exposed HK-2 cells. The cotreatment with an EP4 antagonist abolished these anti-inflammatory and antiapoptotic effects. CONCLUSION: EP4 plays a pivotal role in anti-inflammatory and antiapoptotic effects through Akt and NF-κB signaling after paricalcitol pretreatment in LPS-induced renal proximal tubule cell injury.
Texte intégral:
1
Indice:
WPRIM
Sujet Principal:
Phosphorylation
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Vitamine D
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Ergocalciférol
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Cytokines
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Mort cellulaire
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Apoptose
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Petit ARN interférent
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Cyclooxygenase 2
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Sous-type EP4 des récepteurs des prostaglandines E
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Inflammation
Limites du sujet:
Humans
langue:
En
Texte intégral:
Kidney Research and Clinical Practice
Année:
2017
Type:
Article