Identification of P‐glycoprotein co‐fractionating proteins and specific binding partners in rat brain microvessels

Tome, Margaret E.; Schaefer, Charles; Jacobs, Leigh M.; Zhang, Yifeng; Herndon, Joseph M.; Matty, Fabian O.; Davis, Thomas P.

doi:10.1111/jnc.13106

Cited by 15 publications

(19 citation statements)

References 65 publications

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“…We identified Hsc70 as a protein that co-immunoprecipitates with PgP in rat brain microvessel isolates. 38 Hsc70 is a nucleocytoplasmic shuttle protein in other cell types in culture. 39,40 By identifying both the source and destination of the PgP in the endothelial cells, we can direct our efforts toward elucidating the steps in the PgP trafficking pathways that result in increased PgP at the PM after PIP.…”

Section: Discussionmentioning

confidence: 99%

P-glycoprotein traffics from the nucleus to the plasma membrane in rat brain endothelium during inflammatory pain

Tome

Herndon

Schaefer

et al. 2016

J Cereb Blood Flow Metab

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P-glycoprotein (PgP), a drug efflux pump in blood-brain barrier endothelial cells, is a major clinical obstacle for effective central nervous system drug delivery. Identifying PgP regulatory pathways that can be exploited clinically is critical for improving central nervous system drug delivery. We previously found that PgP activity increases in rat brain microvessels concomitant with decreased central nervous system drug delivery in response to acute peripheral inflammatory pain. In the current study, we tested the hypothesis that PgP traffics to the luminal plasma membrane of the microvessel endothelial cells from intracellular stores during peripheral inflammatory pain. Using immunofluorescence microscopy, we detected PgP in endothelial cell nuclei and in the luminal plasma membrane in control animals. Following peripheral inflammatory pain, luminal PgP staining increased while staining in the nucleus decreased. Biochemical analysis of nuclear PgP content confirmed our visual observations. Peripheral inflammatory pain also increased endothelial cell luminal staining of polymerase 1 and transcript release factor/cavin1 and serum deprivation response protein/cavin2, two caveolar scaffold proteins, without changing caveolin1 or protein kinase C delta binding protein/cavin3 location. Our data (a) indicate that PgP traffics from stores in the nucleus to the endothelial cell luminal membrane in response to peripheral inflammatory pain; (b) provide an explanation for our previous observation that peripheral inflammatory pain inhibits central nervous system drug uptake; and (c) suggest a novel regulatory mechanism for PgP activity in rat brain. KeywordsCaveolin1, P-glycoprotein, protein kinase C delta binding protein/cavin3, polymerase 1 and transcript release factor/ cavin1, serum deprivation response protein/cavin2, trafficking

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Section: Discussionmentioning

confidence: 99%

P-glycoprotein traffics from the nucleus to the plasma membrane in rat brain endothelium during inflammatory pain

Tome

Herndon

Schaefer

et al. 2016

J Cereb Blood Flow Metab

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show abstract

“…Interestingly, while BBB permeability to [ 14 C]sucrose and [ 3 H]codeine is increased during PIP, there is a decrease in BBB permeability to [ 3 H]morphine (285 Da) [82]. Although morphine and codeine are structurally similar (codeine is morphine 3-methyl ether), morphine is a substrate for the ABC efflux transporter P-glycoprotein (P-gp) at the BBB [83]. During PIP, P-gp traffics from the nucleus to the luminal plasma membrane of brain endothelial cells where it is well positioned to efflux morphine back into the bloodstream [84].…”

Section: Pip Effects On Bbb Paracellular Permeabilitymentioning

confidence: 99%

Hypoxic Stress and Inflammatory Pain Disrupt Blood-Brain Barrier Tight Junctions: Implications for Drug Delivery to the Central Nervous System

Lochhead

Ronaldson

Davis

2017

AAPS J

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A functional blood-brain barrier (BBB) is necessary to maintain central nervous system (CNS) homeostasis. Many diseases affecting the CNS, however, alter the functional integrity of the BBB. It has been shown that various diseases and physiological stressors can impact the BBB’s ability to selectively restrict passage of substances from the blood to the brain. Modifications of the BBB’s permeability properties can potentially contribute to the pathophysiology of CNS diseases and result in altered brain delivery of therapeutic agents. Hypoxia and/or inflammation are central components of a number of diseases affecting the CNS. A number of studies indicate hypoxia or inflammatory pain increase BBB paracellular permeability, induce changes in the expression and/or localization of tight junction proteins, and affect CNS drug uptake. In this review, we look at what is currently known with regard to BBB disruption following a hypoxic or inflammatory insult in vivo. Potential mechanisms involved in altering tight junction components at the BBB are also discussed. A more detailed understanding of the mediators involved in changing BBB functional integrity in response to hypoxia or inflammatory pain could potentially lead to new treatments for CNS diseases with hypoxic or inflammatory components. Additionally, greater insight into the mechanisms involved in TJ rearrangement at the BBB may lead to novel strategies to pharmacologically increase delivery of drugs to the CNS.

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“…Caveolaemediated endocytosis has been shown to facilitate the transport of molecules to other parts of the cell (36). An important characteristic of caveolae is detergent insolubility, which can be exploited for fractionation and enrichment (37)(38)(39)(40). However, whether P-gp constantly circulates in cells and is recruited to the cell membrane upon its encounter with its substrate in the cytoplasm or persists on the cell membrane and pumps out its substrates into the extracellular space is not clearly proven.…”

Section: P-gp Is Highly Expressed In Primary Human Brain Endothelial mentioning

confidence: 99%

A2A adenosine receptor modulates drug efflux transporter P-glycoprotein at the blood-brain barrier

Kim¹,

Bynoe²

2016

Journal of Clinical Investigation

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The blood-brain barrier (BBB) protects the brain from toxic substances within the peripheral circulation. It maintains brain homeostasis and is a hurdle for drug delivery to the CNS to treat neurodegenerative diseases, including Alzheimer's disease and brain tumors. The drug efflux transporter P-glycoprotein (P-gp) is highly expressed on brain endothelial cells and blocks the entry of most drugs delivered to the brain. Here, we show that activation of the A2A adenosine receptor (AR) with an FDA-approved A2A AR agonist (Lexiscan) rapidly and potently decreased P-gp expression and function in a timedependent and reversible manner. We demonstrate that downmodulation of P-gp expression and function coincided with chemotherapeutic drug accumulation in brains of WT mice and in primary mouse and human brain endothelial cells, which serve as in vitro BBB models. Lexiscan also potently downregulated the expression of BCRP1, an efflux transporter that is highly expressed in the CNS vasculature and other tissues. Finally, we determined that multiple pathways, including MMP9 cleavage and ubiquitinylation, mediated P-gp downmodulation. Based on these data, we propose that A2A AR activation on BBB endothelial cells offers a therapeutic window that can be fine-tuned for drug delivery to the brain and has potential as a CNS drug-delivery technology.

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Identification of P‐glycoprotein co‐fractionating proteins and specific binding partners in rat brain microvessels

Cited by 15 publications

References 65 publications

P-glycoprotein traffics from the nucleus to the plasma membrane in rat brain endothelium during inflammatory pain

P-glycoprotein traffics from the nucleus to the plasma membrane in rat brain endothelium during inflammatory pain

Hypoxic Stress and Inflammatory Pain Disrupt Blood-Brain Barrier Tight Junctions: Implications for Drug Delivery to the Central Nervous System

A2A adenosine receptor modulates drug efflux transporter P-glycoprotein at the blood-brain barrier

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