Neuroprotective effects of compounds interacting with carrier-mediated amantadine transport across the blood-retinal barrier in rats.

Retinal drug delivery via peripheral administration enhances the safety and efficacy of retinal pharmacotherapy. As retinal drug distribution from the circulating blood is limited by the blood-retinal barrier (BRB), BRB-permeable retinal drugs with potent pharmacological effects are needed for peripheral administration. Our previous research indicated carrier-mediated retinal transport of amantadine, which has neuroprotective effects by inhibiting N-methyl-d-aspartate receptors, across the BRB.

In vitro characterization of taurine transport using the human brain microvascular endothelial cell line as a human blood-brain barrier model.

Taurine, a sulfur-containing β-amino acid, has various roles in the brain including cellular osmoregulation and neuroprotection. For adequate supply to the brain, taurine has to pass through the blood-brain barrier (BBB); however, the associated mechanism behind crossing the human BBB is not fully understood. Therefore, we characterized taurine transport in vitro using the human brain microvascular endothelial (hCMEC/D3) cell line, a model of human BBB function.

Upregulation of P-Glycoprotein and Breast Cancer Resistance Protein Activity in Newly Developed in Vitro Rat Blood-Brain Barrier Spheroids Using Advanced Glycation End-Products.

The blood-brain barrier (BBB) is a dynamic interface controlling the compound translocation between the blood and the brain, thereby maintaining neural homeostasis. There is cumulative evidence that BBB impairment during diabetes mellitus (DM) takes part in the progression of cognitive dementia. As tight junction proteins and ATP-binding cassette (ABC) transporters regulate substance exchange between the circulating blood and brain, the expression and function of these molecules under DM should be fully clarified.

Blood-to-Testis Transport of Ribavirin Involves Carrier-Mediated Processes at the Blood-Testis Barrier.

Ribavirin, an antiretroviral agent targeting the hepatitis C virus, causes male reproductive toxicity. This study investigated the mechanism of ribavirin transport at the blood-testis barrier (BTB). In vivo mouse integration plot analysis after intravenous administration revealed that the net influx clearance of [H]ribavirin in the testis was 3.

Molecular Mechanism of SLC6A8 Dysfunction with c.1699T > C (p.S567P) Mutation in Cerebral Creatine Deficiency Syndromes.

Cerebral creatine deficiency syndromes (CCDS) are neurodevelopmental disorders caused by a decrease in creatine levels in the central nervous system (CNS) due to functional mutations in creatine synthetic enzymes or creatine transporter (CRT/SLC6A8). Although SLC6A8 mutations have been reported to be the most frequent cause of CCDS, sufficient treatment for patients with CCDS harboring SLC6A8 mutations has not yet been achieved. This study aimed to elucidate the molecular mechanism of SLC6A8 dysfunction caused by the c.

Characterization of LysoTracker Red uptake by in vitro model cells of the outer blood-retinal barrier: Implication of lysosomal trapping with cytoplasmic vacuolation and cytotoxicity.

Lysosomal trapping, a physicochemical process in which lipophilic cationic compounds are sequestered in lysosomes, can affect drug disposition and cytotoxicity. To better understand lysosomal trapping at the outer blood-retinal barrier (BRB), we investigated the distribution of LysoTracker Red (LTR), a probe compound for lysosomal trapping, in conditionally immortalized rat retinal pigment epithelial (RPE-J) cells. LTR uptake by RPE-J cells was dependent on temperature and attenuated by ammonium chloride and protonophore, which decreased the pH gradient between the lysosome and cytoplasm, suggesting lysosomal trapping of LTR in RPE-J cells.

Carrier-Mediated Process of Putrescine Elimination at the Rat Blood-Retinal Barrier.

Putrescine is a bioactive polyamine. Its retinal concentration is strictly controlled to maintain a healthy sense of vision. The present study investigated putrescine transport at the blood-retinal barrier (BRB) to gain a better understanding of the mechanisms of putrescine regulation in the retina.

The Structural Characteristics of Compounds Interacting with the Amantadine-Sensitive Drug Transport System at the Inner Blood-Retinal Barrier.

Blood-to-retina transport across the inner blood-retinal barrier (BRB) is a key determinant of retinal drug concentration and pharmacological effect. Recently, we reported on the amantadine-sensitive drug transport system, which is different from well-characterized transporters, at the inner BRB. Since amantadine and its derivatives exhibit neuroprotective effects, it is expected that a detailed understanding of this transport system would lead to the efficient retinal delivery of these potential neuroprotective agents for the treatment of retinal diseases.

Proteomics-Based Transporter Identification by the PICK Method: Involvement of TM7SF3 and LHFPL6 in Proton-Coupled Organic Cation Antiport at the Blood-Brain Barrier.

A proton-coupled organic cation (H/OC) antiporter working at the blood-brain barrier (BBB) in humans and rodents is thought to be a promising candidate for the efficient delivery of cationic drugs to the brain. Therefore, it is important to identify the molecular entity that exhibits this activity. Here, for this purpose, we established the roteomics-based dentification of transporter by rosslinking substrate in eyhole (PICK) method, which combines photo-affinity labeling with comprehensive proteomics analysis using SWATH-MS.

Construction and Functional Evaluation of a Three-Dimensional Blood-Brain Barrier Model Equipped With Human Induced Pluripotent Stem Cell-Derived Brain Microvascular Endothelial Cells.

Purpose: The purpose of this study was to construct and validate an in vitro three-dimensional blood-brain barrier (3DBBB) model system equipped with brain microvascular endothelial cells derived from human induced pluripotent stem cells (hiPS-BMECs).

Methods: The 3D-BBB system was constructed by seeding hiPS-BMECs onto the capillary lane of a MIMETAS OrganoPlate 3-lane coated with fibronectin/collagen IV. hiPS-BMECs were incubated under continuous switchback flow with an OrganoFlow for 2 days.

Transport Characteristics of 6-Mercaptopurine in Brain Microvascular Endothelial Cells Derived From Human Induced Pluripotent Stem Cells.

The likelihood of reoccurrence of acute lymphoblastic leukemia is influenced by the cerebral concentration of the therapeutic agent 6-mercaptopurine (6-MP) during treatment. Therefore, it is important to understand the blood-brain barrier (BBB) transport mechanism of 6-MP. The purpose of this study was to characterize this mechanism using human induced pluripotent stem cell-derived microvascular endothelial cells (hiPS-BMECs).

Functional Investigation of Solute Carrier Family 35, Member F2, in Three Cellular Models of the Primate Blood-Brain Barrier.

Understanding the mechanisms of drug transport across the blood-brain barrier (BBB) is an important issue for regulating the pharmacokinetics of drugs in the central nervous system. In this study, we focused on solute carrier family 35, member F2 (SLC35F2), whose mRNA is highly expressed in the BBB. SLC35F2 protein was enriched in isolated mouse and monkey brain capillaries relative to brain homogenates and was localized exclusively on the apical membrane of MDCKII cells and brain microvascular endothelial cells (BMECs) differentiated from human induced pluripotent stem cells (hiPS-BMECs).

Fibronectin is essential for formation of fenestrae in endothelial cells of the fenestrated capillary.

Endothelial fenestrae are transcellular pores that pierce the capillary walls in endocrine glands such as the pituitary. The fenestrae are covered with a thin fibrous diaphragm consisting of the plasmalemma vesicle-associated protein (PLVAP) that clusters to form sieve plates. The basal surface of the vascular wall is lined by basement membrane (BM) composed of various extracellular matrices (ECMs).

Structural Requirements for Uptake of Diphenhydramine Analogs into hCMEC/D3 Cells Via the Proton-Coupled Organic Cation Antiporter.

There is increasing evidence that a proton-coupled organic cation (H/OC) antiporter facilitates uptake of various central nervous system-active drugs, such as the histamine H1 receptor antagonist diphenhydramine, into the brain. The purpose of this study was to clarify the structural requirements for H/OC antiporter-mediated uptake into hCMEC/D3 cells, an established in vitro model of the human blood-brain barrier, by using a series of diphenhydramine analogs. For this purpose, we synthesized seven tertiary amine analogs and three amide analogs.

Expression and Functional Characterization of Drug Transporters in Brain Microvascular Endothelial Cells Derived from Human Induced Pluripotent Stem Cells.

Brain microvascular endothelial cells derived from human induced pluripotent stem cells (hiPS-BMECs) have been proposed as a new blood-brain barrier model, but their transport function has not been fully clarified. Therefore, in this study, we investigated the gene expression and function of transporters in hiPS-BMECs by means of quantitative reverse transcription-PCR, in vitro transcellular transport studies, and uptake experiments. mRNAs encoding ABC and SLC transporters, such as BCRP, MCT1, CAT1, and GLAST, were highly expressed in hiPS-BMECs.

Transport of Pregabalin Via L-Type Amino Acid Transporter 1 (SLC7A5) in Human Brain Capillary Endothelial Cell Line.

Purpose: The anti-epileptic drug pregabalin crosses the blood-brain barrier (BBB) in spite of its low lipophilicity. This study was performed to determine whether L-type amino acid transporters (LAT1/SLC7A5 and LAT2/SLC7A8) contribute to the uptake of pregabalin.

Methods: Pregabalin uptake by LATs-transfected HEK293 cells or hCMEC/D3 cells, an in vitro human BBB model, was measured by LC-MS/MS analysis.

Design, Synthesis, and Blood-Brain Barrier Transport Study of Pyrilamine Derivatives as Histone Deacetylase Inhibitors.

We designed and synthesized a pyrilamine derivative as a selective class I HDAC inhibitor that targets pyrilamine-sensitive proton-coupled organic cation antiporter (PYSOCA) at the blood-brain barrier (BBB). Introduction of pyrilamine moiety to benzamide type HDAC inhibitors kept selective class I HDAC inhibitory activity and increased BBB permeability. Our BBB transport study showed that compound  is a substrate of PYSOCA.

Impact of Nicotine Transport across the Blood-Brain Barrier: Carrier-Mediated Transport of Nicotine and Interaction with Central Nervous System Drugs.

Nicotine, an addictive substance, is absorbed from the lungs following inhalation of tobacco smoke, and distributed to various tissues such as liver, brain, and retina. Recent in vivo and in vitro studies suggest the involvement of a carrier-mediated transport process in nicotine transport in the lung, liver, and inner blood-retinal barrier. In addition, in vivo studies of influx and efflux transport of nicotine across the blood-brain barrier (BBB) revealed that blood-to-brain influx transport of nicotine is more dominant than brain-to-blood efflux transport of nicotine.

Functional expression of nicotine influx transporter in A549 human alveolar epithelial cells.

Nicotine is a potent addictive alkaloid, and is rapidly absorbed through the alveoli of the lung. However, the transport mechanism of nicotine at the human alveolar epithelial barrier has not been investigated in great detail. In the present study, the transport mechanism of nicotine across alveolar epithelium was investigated in vitro using A549 cells, a human adenocarcinoma-derived cell line with an alveolar epithelial cell like phenotype.

Carrier-Mediated Transport of Nicotine Across the Inner Blood-Retinal Barrier: Involvement of a Novel Organic Cation Transporter Driven by an Outward H(+) Gradient.

The present study was carried out to investigate the blood-to-retina transport of nicotine across the inner blood-retinal barrier (BRB). Using the in vivo vascular injection method, the blood-to-retina influx clearance of nicotine across the BRB was determined as 131 μL/(min?g retina), which is much higher than that of a nonpermeable paracellular marker, and blood-to-retina transport of nicotine was inhibited by organic cations such as pyrilamine and verapamil. The nicotine uptake by a conditionally immortalized rat retinal capillary endothelial cell line (TR-iBRB2 cells), an in vitro model of the inner BRB, exhibited time, temperature, and concentration dependence with a Km of 492 μM.

Involvement of the H+/organic cation antiporter in nicotine transport in rat liver.

Nicotine is an addictive alkaloid in cigarette smoke and is responsible for tobacco dependence. It is important to consider the blood-to-liver transport of nicotine to understand the nicotine elimination from the body because most of the nicotine is converted to inactive metabolites by cytochrome P450 localized in the endoplasmic reticulum of the hepatocytes. In this study, the blood-to-liver transport of nicotine was investigated by means of an in vivo portal vein injection technique in rats, and the in vitro uptake by freshly isolated rat hepatocytes was used to clarify its mechanism.

Blood-to-brain influx transport of nicotine at the rat blood-brain barrier: involvement of a pyrilamine-sensitive organic cation transport process.

Nicotine is the most potent neural pharmacological alkaloid in tobacco, and the modulation of nicotine concentration in the brain is important for smoking cessation therapy. The purpose of this study was to elucidate the net flux of nicotine transport across the blood-brain barrier (BBB) and the major contributor to nicotine transport in the BBB. The in vivo brain-to-blood clearance was determined by a combination of the rat brain efflux index method and a rat brain slice uptake study, and the blood-to-brain transport of nicotine was evaluated by in vivo vascular injection in rats and a conditionally immortalized rat brain capillary endothelial cell line (TR-BBB13 cells) as an in vitro model of the rat BBB.