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Guérit S, Fidan E, Macas J, Czupalla CJ, Figueiredo R, Vijikumar A, Yalcin BH, Thom S, Winter P, Gerhardt H, Devraj K, Liebner S. Astrocyte-derived Wnt growth factors are required for endothelial blood-brain barrier maintenance. Prog Neurobiol 2021; 199:101937. [PMID: 33383106 DOI: 10.1016/j.pneurobio.2020.101937] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 08/28/2020] [Accepted: 10/19/2020] [Indexed: 02/06/2023]
Abstract
Maintenance of the endothelial blood-brain-barrier (BBB) through Wnt/β-catenin signalling is essential for neuronal function. The cells however, providing Wnt growth factors at the adult neurovascular unit (NVU) are poorly explored. Here we show by conditionally knocking out the evenness interrupted (Evi) gene in astrocytes (EviΔAC) that astrocytic Wnt release is crucial for BBB and NVU integrity. EviΔAC mice developed brain oedema and increased vascular tracer leakage. While brain vascularization and endothelial junctions were not altered in 10 and 40 week-old mice, endothelial caveolin(Cav)-1-mediated vesicle formation was increased in vivo and in vitro. Moreover, astrocytic end-feet were swollen, and aquaporin-4 distribution was disturbed, coinciding with decreased astrocytic Wnt activity. Vascular permeability correlated with increased neuronal activation by c-fos staining, indicative of altered neuronal function. Astrocyte-derived Wnts thus serve to maintain Wnt/β-catenin activity in endothelia and in astrocytes, thereby controlling Cav-1 expression, vesicular abundance, and end-feet integrity at the NVU.
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Nonnenmacher M, Wang W, Child MA, Ren XQ, Huang C, Ren AZ, Tocci J, Chen Q, Bittner K, Tyson K, Pande N, Chung CHY, Paul SM, Hou J. Rapid evolution of blood-brain-barrier-penetrating AAV capsids by RNA-driven biopanning. Mol Ther Methods Clin Dev 2020; 20:366-378. [PMID: 33553485 PMCID: PMC7841218 DOI: 10.1016/j.omtm.2020.12.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Accepted: 12/16/2020] [Indexed: 12/26/2022]
Abstract
Therapeutic payload delivery to the central nervous system (CNS) remains a major challenge in gene therapy. Recent studies using function-driven evolution of adeno-associated virus (AAV) vectors have successfully identified engineered capsids with improved blood-brain barrier (BBB) penetration and CNS tropism in mouse. However, these strategies require transgenic animals and thus are limited to rodents. To address this issue, we developed a directed evolution approach based on recovery of capsid library RNA transcribed from CNS-restricted promoters. This RNA-driven screen platform, termed TRACER (Tropism Redirection of AAV by Cell-type-specific Expression of RNA), was tested in the mouse with AAV9 peptide display libraries and showed rapid emergence of dominant sequences. Ten individual variants were characterized and showed up to 400-fold higher brain transduction over AAV9 following systemic administration. Our results demonstrate that the TRACER platform allows rapid selection of AAV capsids with robust BBB penetration and CNS tropism in non-transgenic animals.
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Affiliation(s)
| | - Wei Wang
- Voyager Therapeutics, Cambridge, MA 02139, USA
| | | | | | - Carol Huang
- Voyager Therapeutics, Cambridge, MA 02139, USA
| | | | - Jenna Tocci
- Voyager Therapeutics, Cambridge, MA 02139, USA
| | | | | | | | | | | | | | - Jay Hou
- Voyager Therapeutics, Cambridge, MA 02139, USA
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Song S, Huang H, Guan X, Fiesler V, Bhuiyan MIH, Liu R, Jalali S, Hasan MN, Tai AK, Chattopadhyay A, Chaparala S, Sun M, Stolz DB, He P, Agalliu D, Sun D, Begum G. Activation of endothelial Wnt/β-catenin signaling by protective astrocytes repairs BBB damage in ischemic stroke. Prog Neurobiol 2021; 199:101963. [PMID: 33249091 DOI: 10.1016/j.pneurobio.2020.101963] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 11/02/2020] [Accepted: 11/19/2020] [Indexed: 01/04/2023]
Abstract
The role of astrocytes in dysregulation of blood-brain barrier (BBB) function following ischemic stroke is not well understood. Here, we investigate the effects of restoring the repair properties of astrocytes on the BBB after ischemic stroke. Mice deficient for NHE1, a pH-sensitive Na+/H+ exchanger 1, in astrocytes have reduced BBB permeability after ischemic stroke, increased angiogenesis and cerebral blood flow perfusion, in contrast to wild-type mice. Bulk RNA-sequencing transcriptome analysis of purified astrocytes revealed that ∼177 genes were differentially upregulated in mutant astrocytes, with Wnt7a mRNA among the top genes. Using a Wnt reporter line, we confirmed that the pathway was upregulated in cerebral vessels of mutant mice after ischemic stroke. However, administration of the Wnt/β-catenin inhibitor, XAV-939, blocked the reparative effects of Nhe1-deficient astrocytes. Thus, astrocytes lacking pH-sensitive NHE1 protein are transformed from injurious to "protective" by inducing Wnt production to promote BBB repair after ischemic stroke.
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Kern JK, Geier DA, Homme KG, Geier MR. Examining the evidence that ethylmercury crosses the blood-brain barrier. Environ Toxicol Pharmacol 2020; 74:103312. [PMID: 31841767 DOI: 10.1016/j.etap.2019.103312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 12/06/2019] [Accepted: 12/06/2019] [Indexed: 06/10/2023]
Abstract
Scientific research can provide us with factual, repeatable, measurable, and determinable results. As such, scientific research can provide information that can be used in the decision-making process in the care of patients and in public policy. Although it has been suggested that ethylmercury (C2H5Hg+)-containing compounds do not cross the blood-brain barrier (BBB), this review examines the literature that addresses the question as to whether ethylmercury-containing compounds cross the BBB. The review will begin with cellular studies that provide evidence for the passive and active transport of mercury species across the BBB. Then, animal and clinical studies will be presented that specifically examine whether mercury accumulates in the brain after exposure to ethylmercury-containing compounds or Thimerosal (an ethylmercury-containing compound used as a preservative in vaccines and other drugs that metabolizes or degrades to ethylmercury-containing compounds and thiosalicylate). The results indicate that ethylmercury-containing compounds are actively transported across membranes by the L (leucine-preferring)-amino acid transport (LAT) system, the same as methylmercury-containing compounds. Further, 22 studies from 1971 to 2019 show that exposure to ethylmercury-containing compounds (intravenously, intraperitoneally, topically, subcutaneously, intramuscularly, or intranasally administered) results in accumulation of mercury in the brain. In total, these studies indicate that ethylmercury-containing compounds and Thimerosal readily cross the BBB, convert, for the most part, to highly toxic inorganic mercury-containing compounds, which significantly and persistently bind to tissues in the brain, even in the absence of concurrent detectable blood mercury levels.
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Affiliation(s)
- Janet K Kern
- Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA; CoMeD, Inc, Silver Spring, MD, USA; CONEM US Autism Research Group, Allen, TX, USA.
| | - David A Geier
- Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA; CoMeD, Inc, Silver Spring, MD, USA
| | - Kristin G Homme
- International Academy of Oral Medicine and Toxicology, ChampionsGate, FL, USA
| | - Mark R Geier
- Institute of Chronic Illnesses, Inc, Silver Spring, MD, USA; CoMeD, Inc, Silver Spring, MD, USA
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Kimura I, Dohgu S, Takata F, Matsumoto J, Watanabe T, Iwao T, Yamauchi A, Kataoka Y. Oligodendrocytes upregulate blood-brain barrier function through mechanisms other than the PDGF-BB/PDGFRα pathway in the barrier-tightening effect of oligodendrocyte progenitor cells. Neurosci Lett 2019; 715:134594. [PMID: 31678431 DOI: 10.1016/j.neulet.2019.134594] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 10/18/2019] [Accepted: 10/24/2019] [Indexed: 12/12/2022]
Abstract
White matter lesions are associated with impairment of the blood-brain barrier (BBB), an essential component of the cerebrovasculature. The BBB allows the brain to maintain its highly specialized microenvironment by restricting entry of blood-borne substances including molecules that induce myelin damage. Accumulating evidence suggests that interactions between brain endothelial cells and neighboring cells, including oligodendrocyte progenitor cells (OPCs), are required for the induction and maintenance of BBB function. Here, we compared the ability of OPCs and oligodendrocytes to modulate BBB integrity using co-cultures of rat brain endothelial cells with OPCs or oligodendrocytes. We found that OPCs lowered the brain endothelial permeability to sodium fluorescein, and this enhancement of BBB function was prevented by treatment with AG1296 (a PDGFRα inhibitor). Oligodendrocytes also enhanced BBB integrity. Pharmacological inhibition of PDGFRα did not affect the oligodendrocyte-induced BBB facilitation. These data indicate that oligodendrocytes enhance BBB integrity through pathways other than PDGF-BB/PDGFRα signaling triggered by the brain endothelial cell-derived PDGF-BB. Therefore, our findings suggest that oligodendrocytes constitutively support BBB integrity through soluble factors. Crosstalk between brain endothelial cells and oligodendrocytes could play a facilitatory role in maintaining BBB integrity in the white matter.
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Affiliation(s)
- Ikuya Kimura
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Shinya Dohgu
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Fuyuko Takata
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Junichi Matsumoto
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Takuya Watanabe
- Department of Neuropharmacology, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Takuro Iwao
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Atsushi Yamauchi
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
| | - Yasufumi Kataoka
- Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
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Abstract
Dementia is one of the greatest public health concerns for the modern aging world. Over the last decade, most researchers developing new therapeutic strategies for dementia have focused on amyloid-β. In contrast, numerous recent studies have indicated that vascular risk factors are associated with various forms of dementia, and that in fact most forms of dementia can be considered an extension of vascular disease. Accordingly, it is sensible to pursue treatment approaches that focus on the blood vessels. Blood-brain barrier (BBB) disruptions in the white matter of patients with vascular cognitive impairment (VCI) have been observed using imaging analysis, and might be potential targets for novel VCI treatment. Tight junctions between cerebral endothelial cells play an important role in the function of the BBB, and recent studies have demonstrated the essential role of microRNAs in regulating tight junctions. Further elucidation of the mechanisms of tight junction-disruption in dementia are likely to lead to promising novel treatments. In this article, we summarize current knowledge regarding microRNAs and vascular cognitive impairment and the possibility of utilizing microRNAs as biomarkers for BBB dysfunction, and seek to envision future therapeutic strategies.
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Affiliation(s)
- Kensuke Toyama
- Department of Pharmacology, Ehime University Graduate School of Medicine, Ehime, Japan.
| | - Joshua M Spin
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, United States; VA Palo Alto Health Care System, Palo Alto, CA, United States
| | - Masaki Mogi
- Department of Pharmacology, Ehime University Graduate School of Medicine, Ehime, Japan
| | - Philip S Tsao
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA, United States; VA Palo Alto Health Care System, Palo Alto, CA, United States
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Vilar S, Sobarzo-Sanchez E, Santana L, Uriarte E. Ligand and Structure-based Modeling of Passive Diffusion through the Blood-Brain Barrier. Curr Med Chem 2019; 25:1073-1089. [PMID: 29110594 DOI: 10.2174/0929867324666171106163742] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 09/25/2017] [Accepted: 10/26/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Blood-brain barrier transport is an important process to be considered in drug candidates. The blood-brain barrier protects the brain from toxicological agents and, therefore, also establishes a restrictive mechanism for the delivery of drugs into the brain. Although there are different and complex mechanisms implicated in drug transport, in this review we focused on the prediction of passive diffusion through the blood-brain barrier. METHODS We elaborated on ligand-based and structure-based models that have been described to predict the blood-brain barrier permeability. RESULTS Multiple 2D and 3D QSPR/QSAR models and integrative approaches have been published to establish quantitative and qualitative relationships with the blood-brain barrier permeability. We explained different types of descriptors that correlate with passive diffusion along with data analysis methods. Moreover, we discussed the applicability of other types of molecular structure-based simulations, such as molecular dynamics, and their implications in the prediction of passive diffusion. Challenges and limitations of experimental measurements of permeability and in silico predictive methods were also described. CONCLUSION Improvements in the prediction of blood-brain barrier permeability from different types of in silico models are crucial to optimize the process of Central Nervous System drug discovery and development.
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Affiliation(s)
- Santiago Vilar
- Departamento de Quimica Organica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Eduardo Sobarzo-Sanchez
- Departamento de Quimica Organica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.,Instituto de Investigacion e Innovacion en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago, Chile
| | - Lourdes Santana
- Departamento de Quimica Organica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | - Eugenio Uriarte
- Departamento de Quimica Organica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.,Instituto de Ciencias Quimicas Aplicadas, Facultad de Ingenieria, Universidad Autonoma de Chile, 7500912 Santiago, Chile
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Lan YL, Wang X, Lou JC, Xing JS, Yu ZL, Wang H, Zou S, Ma X, Zhang B. Bufalin inhibits glioblastoma growth by promoting proteasomal degradation of the Na +/K +-ATPase α1 subunit. Biomed Pharmacother 2018; 103:204-215. [PMID: 29653366 DOI: 10.1016/j.biopha.2018.04.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/02/2018] [Accepted: 04/05/2018] [Indexed: 01/02/2023] Open
Abstract
Chansu is a traditional Chinese medicine that is generally recognized as a specific inhibitor of Na+/K+-ATPase. Bufalin, an active component of Chansu, is an endogenous steroid hormone with great potential as a cancer treatment. However, the mechanism by which it exerts its antitumor activity requires further research. Currently, the α1 subunit of Na+/K+-ATPase (ATP1A1) is known to exert important roles in tumorigenesis, and the precise mechanisms underlying the effect of Bufalin on the Na+/K+-ATPase α1 subunit was therefore investigated in this study to determine its role in glioblastoma treatments. The effect of ATP1A1 on the sensitivity of glioblastoma cells to Bufalin was investigated using MTT assays, RT-PCR and siRNA. Western blot was also used to explore the important roles of the ubiquitin-proteasome pathway in the Bufalin-mediated inhibition of ATP1A1. Xenografted mice were used to examine the anti-tumor activity of Bufalin in vivo. LC-MS/MS analysis was performed to determine the ability of Bufalin to traverse the blood-brain barrier (BBB). The results indicated that Bufalin inhibited the expression of ATP1A1 in glioblastoma by promoting the activation of proteasomes and the subsequent protein degradation of ATP1A1, while Bufalin had no effect on ATP1A1 protein synthesis. Bufalin also inhibited the expression of ATP1A1 in xenografted mice and significantly suppressed tumor growth. These data should contribute to future basic and clinical investigations of Bufalin. In conclusion, Bufalin significantly inhibited the expression of ATP1A1 in glioblastoma cells by activating the ubiquitin-proteasome signaling pathway. Bufalin may therefore have the potential to be an effective anti-glioma drug for human glioblastoma in the future.
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Affiliation(s)
- Yu-Long Lan
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, 467 Zhong Shan Road, Dalian, 116023, China; Department of Neurology, The Second Affiliated Hospital of Dalian Medical University, Dalian, 116023, China; Department of Pharmacy, Dalian Medical University, Dalian, 116044, China; Department of Physiology, Dalian Medical University, Dalian, 116044, China
| | - Xun Wang
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, 467 Zhong Shan Road, Dalian, 116023, China
| | - Jia-Cheng Lou
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, 467 Zhong Shan Road, Dalian, 116023, China
| | - Jin-Shan Xing
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, 467 Zhong Shan Road, Dalian, 116023, China
| | - Zhen-Long Yu
- Department of Pharmacy, Dalian Medical University, Dalian, 116044, China
| | - Hongjin Wang
- Department of Neurology, The Second Affiliated Hospital of Dalian Medical University, Dalian, 116023, China
| | - Shuang Zou
- Department of Physiology, Dalian Medical University, Dalian, 116044, China
| | - Xiaochi Ma
- Department of Pharmacy, Dalian Medical University, Dalian, 116044, China.
| | - Bo Zhang
- Department of Neurosurgery, The Second Affiliated Hospital of Dalian Medical University, 467 Zhong Shan Road, Dalian, 116023, China.
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Rempe RG, Hartz AMS, Soldner ELB, Sokola BS, Alluri SR, Abner EL, Kryscio RJ, Pekcec A, Schlichtiger J, Bauer B. Matrix Metalloproteinase-Mediated Blood-Brain Barrier Dysfunction in Epilepsy. J Neurosci 2018; 38:4301-15. [PMID: 29632167 DOI: 10.1523/JNEUROSCI.2751-17.2018] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 03/12/2018] [Accepted: 03/21/2018] [Indexed: 01/08/2023] Open
Abstract
The blood-brain barrier is dysfunctional in epilepsy, thereby contributing to seizure genesis and resistance to antiseizure drugs. Previously, several groups reported that seizures increase brain glutamate levels, which leads to barrier dysfunction. One critical component of barrier dysfunction is brain capillary leakage. Based on our preliminary data, we hypothesized that glutamate released during seizures mediates an increase in matrix-metalloproteinase (MMP) expression and activity levels, thereby contributing to barrier leakage. To test this hypothesis, we exposed isolated brain capillaries from male Sprague Dawley rats to glutamate ex vivo and used an in vivo/ex vivo approach of isolated brain capillaries from female Wistar rats that experienced status epilepticus as an acute seizure model. We found that exposing isolated rat brain capillaries to glutamate increased MMP-2 and MMP-9 protein and activity levels, and decreased tight junction protein levels, which resulted in barrier leakage. We confirmed these findings in vivo in rats after status epilepticus and in brain capillaries from male mice lacking cytosolic phospholipase A2 Together, our data support the hypothesis that glutamate released during seizures signals an increase in MMP-2 and MMP-9 protein expression and activity levels, resulting in blood-brain barrier leakage.SIGNIFICANCE STATEMENT The mechanism leading to seizure-mediated blood-brain barrier dysfunction in epilepsy is poorly understood. In the present study, we focused on defining this mechanism in the brain capillary endothelium. We demonstrate that seizures trigger a pathway that involves glutamate signaling through cytosolic phospholipase A2, which increases MMP levels and decreases tight junction protein expression levels, resulting in barrier leakage. These findings may provide potential therapeutic avenues within the blood-brain barrier to limit barrier dysfunction in epilepsy and decrease seizure burden.
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Amaraneni M, Sharma A, Pang J, Muralidhara S, Cummings BS, White CA, Bruckner JV, Zastre J. Plasma protein binding limits the blood brain barrier permeation of the pyrethroid insecticide, deltamethrin. Toxicol Lett 2016; 250-251:21-8. [PMID: 27016408 DOI: 10.1016/j.toxlet.2016.03.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/14/2016] [Accepted: 03/22/2016] [Indexed: 10/22/2022]
Abstract
Previous pharmacokinetic studies of deltamethrin (DLM) have revealed that brain levels of this highly lipophilic pyrethroid insecticide are only 15-20% of plasma levels. Experiments were performed to assess determinants limiting CNS access including plasma protein binding and the efflux transporter, P-gp. A human brain microvascular endothelial cell line, hCMEC/D3, was utilized as a model in vitro system to evaluate blood-brain barrier (BBB) permeation. Incubation of DLM with a series of human serum albumin (HSA) concentrations showed that unbound (fu) DLM ranged from 80% with 0.01% HSA to ∼20% at the physiologically-relevant 4% HSA. A positive correlation (R=0.987) was seen between fu and cellular uptake. Concentration-dependent uptake of DLM in 0.01% HSA was non-linear and was reduced at 4°C and by the P-gp inhibitor cyclosporine (CSA), indicative of a specific transport process. Cellular accumulation of [(3)H]-paclitaxel, a P-glycoprotein (P-gp) substrate, was increased by CSA but not by DLM, suggesting that DLM is neither a substrate nor an inhibitor of P-gp. The concentration-dependent uptake of DLM from 4% HSA was linear and not significantly impacted by temperature or CSA. In situ brain perfusion studies monitoring brain association of DLM at 0.01% and 4% HSA confirmed the aforementioned in vitro findings. This study demonstrates that brain uptake of DLM under normal physiological conditions appears to be a passive, non-saturable process, limited by the high protein binding of the pyrethroid.
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Affiliation(s)
- Manoj Amaraneni
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Anshika Sharma
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Jing Pang
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Srinivasa Muralidhara
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Brian S Cummings
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Catherine A White
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - James V Bruckner
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States
| | - Jason Zastre
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, 250 west Green St. Athens, GA, 30602, United States.
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