Abstract
Pharmacotherapy of brain HIV-1 infection may be limited by ABC transporters [i.e., P-glycoprotein (P-gp), multidrug resistance protein 1 (Mrp1)] that export antiretroviral drugs from HIV-1 brain cellular targets (i.e., astrocytes, microglia). Using an in vitro astrocyte model of an HIV-1 associated inflammatory response, our laboratory has shown that cytokines [i.e., tumor necrosis factor α (TNF-α), interleukin (IL)-1β, IL-6], which are secreted in response to HIV-1 envelope glycoprotein gp120 exposure, can decrease P-gp functional expression; however, it is unknown whether these same cytokines can alter expression and/or activity of other ABC transporters (i.e., Mrp1). In primary cultures of rat astrocytes, Mrp1 expression was increased by TNF-α (2.7-fold) but was not altered by IL-1β or IL-6. Cellular retention of 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, an Mrp substrate, was reduced in TNF-α-treated astrocytes, suggesting increased Mrp-mediated transport. Pharmacologic inhibition of nuclear factor-κB (NF-κB) signaling with SN50 prevented both TNF-α release and Mrp1 expression changes in astrocytes triggered with gp120; however, SN50 did not attenuate Mrp1 expression in cells triggered with TNF-α. In contrast, Mrp1 functional expression was not altered in the presence of gp120 or TNF-α when astrocyte cultures were pretreated with 1,9-pyrazoloanthrone (SP600125), an established c-Jun N-terminal kinase (JNK) inhibitor. SP600125 did not affect TNF-α release from cultured astrocytes triggered with gp120. Mrp1 mRNA expression was increased after treatment with gp120 (1.6-fold) or TNF-α (1.7-fold), suggesting altered Mrp1 gene transcription. These data suggest that gp120 and TNF-α can up-regulate Mrp1 expression in cultured astrocytes. Furthermore, our results imply that both NF-κB and JNK signaling are involved in Mrp1 regulation during an HIV-1 associated inflammatory response.
Footnotes
This work was supported by the Canadian Institutes of Health Research [Grant MOP-56976] and the Ontario HIV Treatment Network, Ontario Ministry of Health.
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
doi:10.1124/mol.109.059410.
-
ABBREVIATIONS:
- CNS
- central nervous system
- TNF-α
- tumor necrosis factor
- IL
- interleukin
- ABC
- ATP-binding cassette
- P-gp
- P-glycoprotein
- MRP/Mrp
- multidrug resistance protein
- LPS
- lipopolysaccharide
- NF-κB
- nuclear factor-κB
- MAPK
- mitogen-activated protein kinase
- JNK
- c-Jun N-terminal kinase
- PSC833
- valspodar
- BCECF
- 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein
- BAY 11-7082
- (E)3-[(4-methylphenyl)sulfonyl]-2-propenenitrile
- SP600125
- anthra[1–9cd]pyrazol-6(2H)-one
- SAPK
- stress-activated protein kinase
- ELISA
- enzyme-linked immunosorbent assay
- PVDF
- polyvinylidene difluoride
- PCR
- polymerase chain reaction
- AM
- acetoxymethyl ester.
- Received July 14, 2009.
- Accepted January 5, 2010.
- Copyright © 2010 The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|