scholarly journals Engineered nanoparticles for systemic siRNA delivery to malignant brain tumours

Nanoscale ◽  
2019 ◽  
Vol 11 (42) ◽  
pp. 20045-20057 ◽  
Author(s):  
Johan Karlsson ◽  
Yuan Rui ◽  
Kristen L. Kozielski ◽  
Amanda L. Placone ◽  
Olivia Choi ◽  
...  
Keyword(s):  
Mouse Model ◽  
Gene Silencing ◽  
Blood Brain Barrier ◽  
Brain Tumours ◽  
Sirna Delivery ◽  
Engineered Nanoparticles ◽  
Brain Barrier ◽  
Blood Brain ◽  
Malignant Brain Tumours

Bioreducible nanoparticles were engineered for safe and effective systemic siRNA delivery, including crossing the blood–brain barrier to achieve in vivo gene silencing in an orthotopic glioblastoma mouse model.

scholarly journals EXTH-35. LASER INTERSTITIAL THERMAL THERAPY INCREASES BLOOD-BRAIN BARRIER AND BLOOD-TUMOR BARRIER PERMEABILITY IN A MOUSE MODEL OF GLIOBLASTOMA

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi89-vi89
Author(s):  
Mounica Paturu ◽  
Afshin Salehi ◽  
Matthew Caine ◽  
Tatenda Mahlokozera ◽  
Hiroko Yano ◽  
...  
Keyword(s):  
Mouse Model ◽  
Blood Brain Barrier ◽  
Thermal Therapy ◽  
Brain Barrier ◽  
Therapeutic Window ◽  
Normal Brain ◽  
Human Igg ◽  
Laser Interstitial Thermal Therapy ◽  
Blood Brain

Abstract INTRODUCTION A central challenge in glioblastoma treatment is the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB), which prevent access of drugs to the brain and tumor respectively. Recent evidence in patients suggests laser interstitial thermal therapy (LITT), used clinically for tumor ablation, locally disrupts BBB integrity, potentially creating a therapeutic window to deliver otherwise brain-impermeant agents. METHODS A mouse model for LITT, established using a Nd-YAG laser coupled to a 600 mm fiber optic and thermocouple probe, was inserted via burrhole to target the somatosensory cortex. Syngeneic GL261 tumor cells were stereotactically implanted prior to LITT. BBB and BTB permeability were assessed through measurement of fluorescein and doxorubicin after IV injection. Permeability of IV dextran (10 and 70 kDa) and human IgG was monitored by immunohistochemistry (IHC) analysis. Mechanisms of BBB breakdown in vivo were explored utilizing electron microscopy and IHC. RESULTS By fluorescein assay, LITT-induced BBB and BTB permeability began one day post-treatment and was sustained for at least 2 weeks. Additionally, both normal brain and brain tumors demonstrated an increase in Dextran 10 kDa, Dextran 70 kDa, and human IgG extravasation after IV injection in vivo. Mechanistically, we provide evidence that LITT triggers both a decrease in tight junction integrity and an increase in brain endothelial cell transcytosis. As proof-of-concept that LITT can enhance tumor delivery of systemic drugs, LITT increased IV doxorubicin permeability in brain in vivo. Moreover, LITT plus doxorubicin significantly increased survival in brain tumor-bearing mice compared to doxorubicin or LITT alone. CONCLUSIONS Our data suggest that LITT increases BBB and BTB permeability over a defined time window to large molecular weight agents, including antibodies, through multiple cellular mechanisms. Our preclinical results with LITT plus doxorubicin, which mirror a current clinical trial, indicate LITT can enhance the efficacy of systemically delivered drugs.

scholarly journals Protecting P-glycoprotein at the blood–brain barrier from degradation in an Alzheimer’s disease mouse model

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yujie Ding ◽  
Yu Zhong ◽  
Andrea Baldeshwiler ◽  
Erin L. Abner ◽  
Björn Bauer ◽  
...  
Keyword(s):  
Mouse Model ◽  
Protein Expression ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Activity Levels ◽  
Transport Activity ◽  
Brain Capillaries ◽  
P Glycoprotein ◽  
Blood Brain

AbstractBackgroundFailure to clear Aβ from the brain is partly responsible for Aβ brain accumulation in Alzheimer’s disease (AD). A critical protein for clearing Aβ across the blood-brain barrier is the efflux transporter P-glycoprotein (P-gp). In AD, P-gp levels are reduced, which contributes to impaired Aβ brain clearance. However, the mechanism responsible for decreased P-gp levels is poorly understood and there are no strategies available to protect P-gp. We previously demonstrated in isolated brain capillariesex vivothat human Aβ40 (hAβ40) triggers P-gp degradation by activating the ubiquitin-proteasome pathway. In this pathway, hAβ40 initiates P-gp ubiquitination, leading to internalization and proteasomal degradation of P-gp, which then results in decreased P-gp protein expression and transport activity levels. Here, we extend this line of research and present results from anin vivostudy using a transgenic mouse model of AD (human amyloid precursor protein (hAPP)-overexpressing mice; Tg2576).MethodsIn our study, hAPP mice were treated with vehicle, nocodazole (NCZ, microtubule inhibitor to block P-gp internalization), or a combination of NCZ and the P-gp inhibitor cyclosporin A (CSA). We determined P-gp protein expression and transport activity levels in isolated mouse brain capillaries and Aβ levels in plasma and brain tissue.ResultsTreating hAPP mice with 5 mg/kg NCZ for 14 days increased P-gp levels to levels found in WT mice. Consistent with this, P-gp-mediated hAβ42 transport in brain capillaries was increased in NCZ-treated hAPP mice compared to untreated hAPP mice. Importantly, NCZ treatment significantly lowered hAβ40 and hAβ42 brain levels in hAPP mice, whereas hAβ40 and hAβ42 levels in plasma remained unchanged.ConclusionsThese findings provide in vivo evidence that microtubule inhibition maintains P-gp protein expression and transport activity levels, which in turn helps to lower hAβ brain levels in hAPP mice. Thus, protecting P-gp at the blood-brain barrier may provide a novel therapeutic strategy for AD and other Aβ-based pathologies.

scholarly journals Contribution of thrombin-reactive brain pericytes to blood-brain barrier dysfunction in an in vivo mouse model of obesity-associated diabetes and an in vitro rat model

PLoS ONE ◽  
2017 ◽  
Vol 12 (5) ◽  
pp. e0177447 ◽  
Author(s):  
Takashi Machida ◽  
Fuyuko Takata ◽  
Junichi Matsumoto ◽  
Tomoyuki Miyamura ◽  
Ryosuke Hirata ◽  
...  
Keyword(s):  
Mouse Model ◽  
Blood Brain Barrier ◽  
Rat Model ◽  
Brain Barrier ◽  
Barrier Dysfunction ◽  
Blood Brain ◽  
Brain Pericytes

scholarly journals Protecting P-glycoprotein at the Blood-Brain Barrier from Degradation in an Alzheimer’s Disease Mouse Model

2020 ◽  
Author(s):  
Yujie Ding ◽  
Yu Zhong ◽  
Andrea Baldeshwiler ◽  
Erin L. Abner ◽  
Björn Bauer ◽  
...  
Keyword(s):  
Mouse Model ◽  
Protein Expression ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Activity Levels ◽  
Transport Activity ◽  
Brain Capillaries ◽  
P Glycoprotein ◽  
Blood Brain

Abstract Background. Failure to clear Aβ from the brain is partly responsible for Aβ brain accumulation in Alzheimer’s disease (AD). A critical protein for clearing Aβ across the blood-brain barrier is the efflux transporter P-glycoprotein (P-gp). In AD, P-gp levels are reduced, which contributes to impaired Aβ brain clearance. However, the mechanism responsible for decreased P-gp levels is poorly understood and there are no strategies available to protect P-gp. We previously demonstrated in isolated brain capillaries ex vivo that human Aβ40 (hAβ40) triggers P-gp degradation by activating the ubiquitin-proteasome pathway. In this pathway, hAβ40 initiates P-gp ubiquitination, leading to internalization and proteasomal degradation of P-gp, which then results in decreased P-gp protein expression and transport activity levels. Here, we extend this line of research and present results from an in vivo study using a transgenic mouse model of AD (human amyloid precursor protein (hAPP)-overexpressing mice; Tg2576). Methods. In our study, hAPP mice were treated with vehicle, nocodazole (NCZ, microtubule inhibitor to block P-gp internalization), or a combination of NCZ and the P-gp inhibitor cyclosporin A (CSA). We determined P-gp protein expression and transport activity levels in isolated mouse brain capillaries and Aβ levels in plasma and brain tissue. Results. Treating hAPP mice with 5 mg/kg NCZ for 14 days protected P-gp from degradation. Consistent with this, P-gp-mediated hAβ42 transport in brain capillaries was increased in NCZ-treated hAPP mice compared to untreated hAPP mice. Importantly, NCZ treatment significantly lowered hAβ40 and hAβ42 brain levels in hAPP mice, whereas hAβ40 and hAβ42 levels in plasma remained unchanged. Conclusions. These findings provide in vivo proof that blocking P-gp internalization protects P-gp from degradation and maintains P-gp protein expression and transport activity levels, which in turn lowers hAβ brain levels. Thus, protecting P-gp at the blood-brain barrier may provide a novel therapeutic target for AD and other Aβ-based pathologies.

scholarly journals Blood-Brain Barrier Disruption Increases Amyloid-Related Pathology in TgSwDI Mice

2021 ◽  
Vol 22 (3) ◽  
pp. 1231
Author(s):  
Ihab M. Abdallah ◽  
Kamal M. Al-Shami ◽  
Euitaek Yang ◽  
Amal Kaddoumi
Keyword(s):  
Mouse Model ◽  
Blood Brain Barrier ◽  
High Throughput Screening ◽  
Amyloid Β ◽  
Brain Barrier ◽  
Amyloid Angiopathy ◽  
Cancer Resistance ◽  
Screening Assay ◽  
Blood Brain ◽  
High Throughput Screening Assay

In Alzheimer’s disease (AD), several studies have reported blood-brain barrier (BBB) breakdown with compromised function. P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) are transport proteins localized at the BBB luminal membrane and play an important role in the clearance of amyloid-β (Aβ). The purpose of this study was to investigate the effect of pharmacological inhibition of Aβ efflux transporters on BBB function and Aβ accumulation and related pathology. Recently, we have developed an in vitro high-throughput screening assay to screen for compounds that modulate the integrity of a cell-based BBB model, which identified elacridar as a disruptor of the monolayer integrity. Elacridar, an investigational compound known for its P-gp and BCRP inhibitory effect and widely used in cancer research. Therefore, it was used as a model compound for further evaluation in a mouse model of AD, namely TgSwDI. TgSwDI mouse is also used as a model for cerebral amyloid angiopathy (CAA). Results showed that P-gp and BCRP inhibition by elacridar disrupted the BBB integrity as measured by increased IgG extravasation and reduced expression of tight junction proteins, increased amyloid deposition due to P-gp, and BCRP downregulation and receptor for advanced glycation end products (RAGE) upregulation, increased CAA and astrogliosis. Further studies revealed the effect was mediated by activation of NF-κB pathway. In conclusion, results suggest that BBB disruption by inhibiting P-gp and BCRP exacerbates AD pathology in a mouse model of AD, and indicate that therapeutic drugs that inhibit P-gp and BCRP could increase the risk for AD.

scholarly journals Pharmacokinetics and Molecular Modeling Indicate nAChRα4-Derived Peptide HAEE Goes through the Blood–Brain Barrier

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 909
Author(s):  
Yurii A. Zolotarev ◽  
Vladimir A. Mitkevich ◽  
Stanislav I. Shram ◽  
Alexei A. Adzhubei ◽  
Anna P. Tolstova ◽  
...  
Keyword(s):  
Molecular Modeling ◽  
Mouse Model ◽  
Blood Brain Barrier ◽  
Brain Barrier ◽  
Laboratory Animals ◽  
Pharmacokinetic Parameters ◽  
Pharmacokinetic Data ◽  
Bolus Administration ◽  
Blood Brain ◽  
The Brain

One of the treatment strategies for Alzheimer’s disease (AD) is based on the use of pharmacological agents capable of binding to beta-amyloid (Aβ) and blocking its aggregation in the brain. Previously, we found that intravenous administration of the synthetic tetrapeptide Acetyl-His-Ala-Glu-Glu-Amide (HAEE), which is an analogue of the 35–38 region of the α4 subunit of α4β2 nicotinic acetylcholine receptor and specifically binds to the 11–14 site of Aβ, reduced the development of cerebral amyloidogenesis in a mouse model of AD. In the current study on three types of laboratory animals, we determined the biodistribution and tissue localization patterns of HAEE peptide after single intravenous bolus administration. The pharmacokinetic parameters of HAEE were established using uniformly tritium-labeled HAEE. Pharmacokinetic data provided evidence that HAEE goes through the blood–brain barrier. Based on molecular modeling, a role of LRP1 in receptor-mediated transcytosis of HAEE was proposed. Altogether, the results obtained indicate that the anti-amyloid effect of HAEE, previously found in a mouse model of AD, most likely occurs due to its interaction with Aβ species directly in the brain.

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