Spironolactone ameliorates lipopolysaccharide-induced cholestasis in rats by improving Mrp2 function: Role of transcriptional and post-transcriptional mechanisms

RAZORI, MARÍA VALERIA; MARTÍN, PAMELA L.; MAIDAGAN, PAULA M.; BAROSSO, ISMAEL R.; CIRIACI, NADIA; ANDERMATTEN, ROMINA B.; SÁNCHEZ POZZI, ENRIQUE J.; BASIGLIO, CECILIA L.; ROMA, MARCELO G.*; RUIZ, MARÍA LAURA*

LIFE SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020

0024-3205

Aims: Lipopolysaccharide (LPS) induces inflammatory cholestasis by impairingexpression, localization, and function of carriers involved in bile formation, e.g. bile saltexport pump (Bsep) and multidrug resistance associated protein 2 (Mrp2). A specifictherapy against this disease is still lacking. Therefore, we evaluated the anticholestaticeffects of spironolactone (SL), a PXR ligand that regulates bile salt homeostasis, upregulates Mrp2, and bears anti-inflammatory properties.Main methods: Male Wistar rats were divided into four groups: Control, SL (83.3mg/kg/day of SL, i.p., for 3 days), LPS (2.5 mg/kg/day, i.p., at 8 am of the last 2 days,and 1.5 mg/kg/day at 8 pm of the last day), and SL+LPS. Biliary and plasma parametersand the expression, function and localization of Mrp2 and Bsep were evaluated.Key findings: SL partially prevented LPS-induced drop of basal bile flow by normalizingthe bile salt-independent fraction of bile flow (BSIBF), via improvement of glutathioneoutput. This was due to a recovery in Mrp2 transport function, the major canalicularglutathione transporter, estimated by monitoring the output of its exogenouslyadministered substrate dibromosulfophthalein. SL counteracted the LPS-induceddownregulation of Mrp2, but not that of Bsep, at both mRNA and protein levels. LPSinduced endocytic internalization of both transporters, visualized byimmunofluorescence followed by confocal microscopy, and SL partially prevented thisrelocalization. SL did not prevent the increase in IL-1β, IL-6, and TNF-α plasma levels.Significance: SL prevents the impairment in Mrp2 expression and localization, and theresulting recovery of Mrp2 function normalizes the BSIBF by improving glutathioneexcretion.