Occludin regulates glucose uptake and ATP production in pericytes by influencing AMP-activated protein kinase activity

Energetic regulation at the blood-brain barrier is critical for maintaining its integrity, transport capabilities, and brain demands for glucose. However, the underlying mechanisms that regulate these processes are still poorly explored. We recently characterized the protein occludin as a NADH oxidase and demonstrated its influence on the expression and activation of the histone deacetylase SIRT-1. Because SIRT-1 works in concert with AMP-activated protein kinase (AMPK) (AMPK), we investigated the impact of occludin on this metabolic switch. Here we show that in blood-brain barrier pericytes, occludin promotes AMPK expression and activation, influencing the expression of glucose transporters GLUT-1 and GLUT-4, glucose uptake, and ATP content. Furthermore, occludin expression, AMP-dependent protein kinase activity, and glucose uptake were altered under inflammatory (TNFα) and infectious (HIV) conditions. We also show that pericytes share glucose and mitochondria with astrocytes, and that occludin levels modify the ability of pericytes to share those energetic resources. In addition, we demonstrate that murine mitochondria can be transferred from live brain microvessels to energetically impaired human astrocytes, promoting their survival. Our findings demonstrate that occludin plays an important role in blood-brain barrier pericyte metabolism by influencing AMPK protein kinase activity, glucose uptake, ATP production, and by regulating the ability of pericytes to interact metabolically with astrocytes.

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Metformin induces up-regulation of blood–brain barrier functions by activating AMP-activated protein kinase in rat brain microvascular endothelial cells

Biochemical and Biophysical Research Communications ◽

10.1016/j.bbrc.2013.03.036 ◽

2013 ◽

Vol 433 (4) ◽

pp. 586-590 ◽

Cited By ~ 37

Author(s):

Fuyuko Takata ◽

Shinya Dohgu ◽

Junichi Matsumoto ◽

Takashi Machida ◽

Shuji Kaneshima ◽

...

Keyword(s):

Endothelial Cells ◽

Protein Kinase ◽

Rat Brain ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Microvascular Endothelial Cells ◽

Brain Microvascular Endothelial Cells ◽

Barrier Functions ◽

Blood Brain ◽

Amp Activated Protein Kinase

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Melatonin alleviates lipopolysaccharide-compromised integrity of blood-brain barrier through activating AMP-activated protein kinase in old mice

Aging Cell ◽

10.1111/acel.12572 ◽

2017 ◽

Vol 16 (2) ◽

pp. 414-421 ◽

Cited By ~ 24

Author(s):

Xiaona Wang ◽

Gai-Xiu Xue ◽

Wen-Cao Liu ◽

Hui Shu ◽

Mengwei Wang ◽

...

Keyword(s):

Protein Kinase ◽

Blood Brain Barrier ◽

Brain Barrier ◽

Blood Brain ◽

Amp Activated Protein Kinase ◽

Old Mice

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Isoleucine, a Blood Glucose-Lowering Amino Acid, Increases Glucose Uptake in Rat Skeletal Muscle in the Absence of Increases in AMP-Activated Protein Kinase Activity

Journal of Nutrition ◽

10.1093/jn/135.9.2103 ◽

2005 ◽

Vol 135 (9) ◽

pp. 2103-2108 ◽

Cited By ~ 71

Author(s):

Masako Doi ◽

Ippei Yamaoka ◽

Mitsuo Nakayama ◽

Shinji Mochizuki ◽

Kunio Sugahara ◽

...

Keyword(s):

Skeletal Muscle ◽

Blood Glucose ◽

Amino Acid ◽

Protein Kinase ◽

Glucose Uptake ◽

Kinase Activity ◽

Protein Kinase Activity ◽

Rat Skeletal Muscle ◽

Glucose Lowering ◽

Amp Activated Protein Kinase

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Miniaturization and Automation of a Human In Vitro Blood–Brain Barrier Model for the High-Throughput Screening of Compounds in the Early Stage of Drug Discovery

Pharmaceutics ◽

10.3390/pharmaceutics13060892 ◽

2021 ◽

Vol 13 (6) ◽

pp. 892

Author(s):

Elisa L. J. Moya ◽

Elodie Vandenhaute ◽

Eleonora Rizzi ◽

Marie-Christine Boucau ◽

Johan Hachani ◽

...

Keyword(s):

Drug Discovery ◽

Blood Brain Barrier ◽

Early Stage ◽

Molecular Transport ◽

Brain Barrier ◽

Blood Brain ◽

Cns Drugs ◽

The Impact ◽

The Brain

Central nervous system (CNS) diseases are one of the top causes of death worldwide. As there is a difficulty of drug penetration into the brain due to the blood–brain barrier (BBB), many CNS drugs treatments fail in clinical trials. Hence, there is a need to develop effective CNS drugs following strategies for delivery to the brain by better selecting them as early as possible during the drug discovery process. The use of in vitro BBB models has proved useful to evaluate the impact of drugs/compounds toxicity, BBB permeation rates and molecular transport mechanisms within the brain cells in academic research and early-stage drug discovery. However, these studies that require biological material (animal brain or human cells) are time-consuming and involve costly amounts of materials and plastic wastes due to the format of the models. Hence, to adapt to the high yields needed in early-stage drug discoveries for compound screenings, a patented well-established human in vitro BBB model was miniaturized and automated into a 96-well format. This replicate met all the BBB model reliability criteria to get predictive results, allowing a significant reduction in biological materials, waste and a higher screening capacity for being extensively used during early-stage drug discovery studies.

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CdSe/ZnS Core-Shell-Type Quantum Dot Nanoparticles Disrupt the Cellular Homeostasis in Cellular Blood–Brain Barrier Models

International Journal of Molecular Sciences ◽

10.3390/ijms22031068 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1068

Author(s):

Katarzyna Dominika Kania ◽

Waldemar Wagner ◽

Łukasz Pułaski

Keyword(s):

Gene Expression ◽

Quantum Dot ◽

Blood Brain Barrier ◽

Protein Gene ◽

Brain Barrier ◽

Core Shell ◽

Cellular Homeostasis ◽

Blood Brain ◽

Shell Type ◽

The Impact

Two immortalized brain microvascular endothelial cell lines (hCMEC/D3 and RBE4, of human and rat origin, respectively) were applied as an in vitro model of cellular elements of the blood–brain barrier in a nanotoxicological study. We evaluated the impact of CdSe/ZnS core-shell-type quantum dot nanoparticles on cellular homeostasis, using gold nanoparticles as a largely bioorthogonal control. While the investigated nanoparticles had surprisingly negligible acute cytotoxicity in the evaluated models, a multi-faceted study of barrier-related phenotypes and cell condition revealed a complex pattern of homeostasis disruption. Interestingly, some features of the paracellular barrier phenotype (transendothelial electrical resistance, tight junction protein gene expression) were improved by exposure to nanoparticles in a potential hormetic mechanism. However, mitochondrial potential and antioxidant defences largely collapsed under these conditions, paralleled by a strong pro-apoptotic shift in a significant proportion of cells (evidenced by apoptotic protein gene expression, chromosomal DNA fragmentation, and membrane phosphatidylserine exposure). Taken together, our results suggest a reactive oxygen species-mediated cellular mechanism of blood–brain barrier damage by quantum dots, which may be toxicologically significant in the face of increasing human exposure to this type of nanoparticles, both intended (in medical applications) and more often unintended (from consumer goods-derived environmental pollution).

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