Targeting brain tumors with innovative nanocarriers:bridging the gap through the blood-brain barrier

Background:Glioblastoma multiforme(GBM)is recognized as the most lethal and most highly invasive tumor.The high likelihood of treatment failure arises fromthe presence of the blood-brain barrier(BBB)and stemcells around GBM,which avert the entry of chemotherapeutic drugs into the tumormass.Objective:Recently,several researchers have designed novel nanocarrier systems like liposomes,dendrimers,metallic nanoparticles,nanodiamonds,and nanorobot approaches,allowing drugs to infiltrate the BBB more efficiently,opening up innovative avenues to prevail over therapy problems and radiation therapy.Methods:Relevant literature for this manuscript has been collected from a comprehensive and systematic search of databases,for example,PubMed,Science Direct,Google Scholar,and others,using specific keyword combinations,including“glioblastoma,”“brain tumor,”“nanocarriers,”and several others.Conclusion:This review also provides deep insights into recent advancements in nanocarrier-based formulations and technologies for GBM management.Elucidation of various scientific advances in conjunction with encouraging findings concerning the future perspectives and challenges of nanocarriers for effective brain tumor management has also been discussed.

Functionalized lipid nanoparticles modulate the blood-brain barrier and eliminate α-synuclein to repair dopamine neurons

The challenge in the clinical treatment of Parkinson's disease lies in the lack of disease-modifying therapies that can halt or slow down the progression. Peptide drugs, such as exenatide (Exe), with potential disease-modifying efficacy, have difficulty in crossing the blood-brain barrier (BBB) due to their large molecular weight. Herein, we fabricate multi-functionalized lipid nanoparticles (LNP) Lpc-BoSA/CSO with BBB targeting, permeability-increasing and responsive release functions. Borneol is chemically bonded with stearic acid and, as one of the components of Lpc-BoSA/CSO, is used to increase BBB permeability. Immunofluorescence results of brain tissue of 15-month-old C57BL/6 mice show that Lpc-BoSA/CSO disperses across the BBB into brain parenchyma, and the amount is 4.21 times greater than that of conventional LNP. Motor symptoms of mice in Lpc-BoSA/CSO-Exe group are significantly improved, and the content of dopamine is 1.85 times (substantia nigra compacta) and 1.49 times (striatum) that of PD mice. α-Synuclein expression and Lewy bodies deposition are reduced to 51.85% and 44.72% of PD mice, respectively. Immunohistochemical mechanism studies show AKT expression in Lpc-BoSA/CSO-Exe is 4.23 times that of PD mice and GSK-3β expression is reduced to 18.41%. Lpc-BoSA/CSO-Exe could reduce the production of α-synuclein and Lewy bodies through AKT/GSK-3β pathway, and effectively prevent the progressive deterioration of Parkinson's disease. In summary, Lpc-BoSA/CSO-Exe increases the entry of exenatide into brain and promotes its clinical application for Parkinson's disease therapy.

Activation of the wnt/β-catenin/CYP1B1 pathway alleviates oxidative stress and protects the blood-brain barrier under cerebral ischemia/reperfusion conditions

Accumulating evidence suggests that oxidative stress and the Wnt/β-catenin pathway participate in stroke-induced disruption of the blood-brain barrier.However,the potential links between them following ischemic stroke remain largely unknown.The present study found that cerebral ischemia leads to oxidative stress and repression of the Wnt/β-catenin pathway.Meanwhile,Wnt/β-catenin pathway activation by the pharmacological inhibito r,TWS119,relieved oxidative stress,increased the levels of cytochrome P4501B1(CYP1B1)and tight junction-associated proteins(zonula occludens-1[ZO-1],occludin and claudin-5),as well as brain microvascular density in cerebral ischemia rats.Moreove r,rat brain microvascular endothelial cells that underwent oxygen glucose deprivation/reoxygenation displayed intense oxidative stress,suppression of the Wnt/β-catenin pathway,aggravated cell apoptosis,downregulated CYP1B1and tight junction protein levels,and inhibited cell prolife ration and migration.Overexpression ofβ-catenin or knockdown ofβ-catenin and CYP1B1 genes in rat brain mic rovascular endothelial cells at least partly ameliorated or exacerbated these effects,respectively.In addition,small interfering RNA-mediatedβ-catenin silencing decreased CYP1B1 expression,whereas CYP1B1 knoc kdown did not change the levels of glycogen synthase kinase 3β,Wnt-3a,andβ-catenin proteins in rat brain microvascular endothelial cells after oxygen glucose deprivatio n/reoxygenation.Thus,the data suggest that CYP1B1 can be regulated by Wnt/β-catenin signaling,and activation of the Wnt/β-catenin/CYP1B1 pathway contributes to alleviation of oxidative stress,increased tight junction levels,and protection of the blood-brain barrier against ischemia/hypoxia-induced injury.

The importance of laminin at the blood-brain barrier

The blood-brain barrier is a unique property of central nervous system blood vessels that protects sensitive central nervous system cells from potentially harmful blood components.The mechanistic basis of this barrier is found at multiple levels,including the adherens and tight junction proteins that tightly bind adjacent endothelial cells and the influence of neighboring pericytes,microglia,and astrocyte endfeet.In addition,extracellular matrix components of the vascular basement membrane play a critical role in establishing and maintaining blood-brain barrier integrity,not only by providing an adhesive substrate for blood-brain barrier cells to adhere to,but also by providing guidance cues that strongly influence vascular cell behavior.The extracellular matrix protein laminin is one of the most abundant components of the basement membrane,and several lines of evidence suggest that it plays a key role in directing blood-brain barrier behavior.In this review,we describe the basic structure of laminin and its receptors,the expression patterns of these molecules in central nervous system blood vessels and how they are altered in disease states,and most importantly,how genetic deletion of different laminin isoforms or their receptors reveals the contribution of these molecules to blood-brain barrier function and integrity.Finally,we discuss some of the important unanswered questions in the field and provide a“to-do”list of some of the critical outstanding experiments.

The role of fibronectin in multiple sclerosis and the effect of drug delivery across the blood-brain barrier

Remyelination failure is one of the main characteristics of multiple sclerosis and is potentially correlated with disease progression.Previous research has shown that the extracellular matrix is associated with remyelination failure because remodeling of the matrix often fails in both chronic and progressive multiple sclerosis.Fibronectin aggregates are assembled and persistently exist in chronic multiple sclerosis,thus inhibiting remyelination.Although many advances have been made in the mechanisms and treatment of multiple sclerosis,it remains very difficult for drugs to reach pathological brain tissues;this is due to the complexity of brain structure and function,especially the existence of the blood-brain barrier.Therefore,herein,we review the effects of fibronectin aggregates on multiple sclerosis and the efficacy of different forms of drug delivery across the blood-brain barrier in the treatment of this disease.

Human induced pluripotent stem cell based in vitro models of the blood-brain barrier： the future standard？

There is an urgent and tremendous need for human dis- ease models in drug development in order to improve pre- clinical predictability. In the case of brain disorders drugs have to cross the blood-brain barrier （BBB） to enter the central nervous system （CNS）. It was estimated that more than 95% of the drugs cannot cross the BBB.

Effects of Minimally Invasive Puncture and Drainage of Intracranial Hematoma on the Blood-brain Barrier in Patients with Cerebral Hemorrhage

The effects of minimally invasive surgery on the blood-brain barrier （BBB） of 30 patients with cerebral hemorrhage were investigated. Difference of the BBB index and serum MBP concentration were assessed in 15 cases of conservative treatment group and 15 cases of minimally invasive surgery group. The BBB index in minimally invasive surgery group was significantly lower than in conservative treatment group （P〈0.05）, and the BBB index in the two treatment groups was significantly higher than in control group （P〈0.01）. Serum MBP concentration in minimally invasive surgery group was significantly lower than in conservative treatment group （P〈0.05）, and that in the two treatment groups was significantly higher than in control group （P〈0.01）. It was suggested the permeability of BBB in patients with cerebral hemorrhage was increased, and BBB index and serum MBP concentration in patients with cerebral hemorrhage were increased. Minimally invasive surgery can reduce the lesion of cytotoxicity to BBB and cerebral edema.

Intranasal nerve growth factor bypasses the blood-brain barrier and affects spinal cord neurons in spinal cord injury

The purpose of this work was to investigate whether, by intranasal administration, the nerve growth factor bypasses the blood-brain barrier and turns over the spinal cord neurons and if such therapeutic approach could be of value in the treatment of spinal cord injury. Adult Sprague-Dawley rats with intact and injured spinal cord received daily intranasal nerve growth factor administration in both nostrils for 1 day or for 3 consecutive weeks. We found an in-creased content of nerve growth factor and enhanced expression of nerve growth factor receptor in the spinal cord 24 hours after a single intranasal administration of nerve growth factor in healthy rats, while daily treatment for 3 weeks in a model of spinal cord injury improved the deifcits in locomotor behaviour and increased spinal content of both nerve growth factor and nerve growth factor receptors. These outcomes suggest that the intranasal nerve growth factor bypasses blood-brain barrier and affects spinal cord neurons in spinal cord injury. They also suggest exploiting the possible therapeutic role of intranasally delivered nerve growth factor for the neuroprotection of damaged spinal nerve cells.

In vitro model of the blood-brain barrier established by co-culture of primary cerebral microvascular endothelial and astrocyte cells

Drugs for the treatment and prevention of nervous system diseases must permeate the bloodbrain barrier to take effect.In vitro models of the blood-brain barrier are therefore important in the investigation of drug permeation mechanisms.However,to date,no unified method has been described for establishing a blood-brain barrier model.Here,we modified an in vitro model of the blood-brain barrier by seeding brain microvascular endothelial cells and astrocytes from newborn rats on a polyester Transwell cell culture membrane with 0.4-μm pores,and conducted transepithelial electrical resistance measurements,leakage tests and assays for specific bloodbrain barrier enzymes.We show that the permeability of our model is as low as that of the bloodbrain barrier in vivo.Our model will be a valuable tool in the study of the mechanisms of action of neuroprotective drugs.

Effect of Tong-Qiao-Huo-Xue decoction on the expressions of related proteins of the blood-brain barrier and analysis of constituents in cerebrospinal fluid of cerebral ischemic rats

OBJECTIVE To evaluate the effects of Tong-Qiao-Huo-Xue decoction(TQHXD)on the bloodbrain barrier(BBB)permeability and the expressions of related proteins on the rats;and to analyse the constituents in the cerebrospinal fluid on the rats with cerebral ischemic injury.METHODS Cerebral ischemia rats were induced by middle cerebral artery occlusion(MCAO).Adult male sprague-dawley(SD)rats were randomly divided into seven groups:sham-group;model group;nimodipine(NMP)-treated group and nao mai tai(NMT)-treated group were set as positive drug control groups;TQHXD-treated group(3,6 and 12g·kg-1body weight);The neurological function of rats was estimated by neurological defect scoring after the 1,7and 15 dafter administration.Histological structure of the brain in rats were observed by hematoxylin and eosin(H&E)staining.Ultramicrostructural features of hippocampus neurons and the opening of tight junction(TJ)of BBB in rats were observed by transmission electron microscope(TEM).Western blotting was performed to detect the expression of ZO-1,occludin,claudin-5,AQP-4 and MMP-9 in BBB after cerebral ischemia injury.Component analysis experiments:adult male SD rats were randomly divided into four groups:Distilled water was administered intragastrically sham-operated rats;Distilled water was administered intragastrically model rats by MCAO;TQHXD was administered intragatrically to rats in sham-operated group;TQHXD was administered intragestrically to rats in model group by MCAO.GC and HPLC was used to detect three compounds,namely,muscone,ligustilide and hydroxysafflor yellow A,in rats cerebrospinal fluid(CSF)after oral administration of TQHXD.Finally,samples of cerebrospinal fluid of rats in each group were compared with single medicine so as to explicit the three compounds come from which herb.RESULTS TQHXD significantly reduced the neurological defect scores.Histological examination indicated that dense neuropil and largely surviving neurons had been seen in TQHXD-treated rats.TEM observation revealed that TQHXD could significantly inhibit the damage of hippocampal neurons and reduce the opening of TJ.The decreased protein expression levels of claudin-5,occludin,ZO-1 and the increased protein expression levels of AQP-4 and MMP-9in cerebral ischemia tissue were significantly prevented by treatment of TQHXD.Analysis of experimental results showed that muscone,ligustilide and hydroxysafflor yellow A could penetrate the BBB into the CSF,and the content of the model group was lower than that of sham group after intragastric administration of TQHXD.CONCLUSION These results demonstrated that TQHXD may act as a potential neuroprotective agent against BBB damage for cerebral ischemia through protecting of hippocampus neurons,reducing the opening of TJ and decreasing the permeability of BBB by up-regulating ZO-1,occludin,claudin-5 expressions,down-regulating AQP-4 and MMP-9 expressions.The effect of TQHXD on the decrease of the opening of TJ also reduced the content of muscone,ligustilide and hydroxysafflor yellow A in cerebrospinal fluid.

Limb remote ischemic postconditioning protects integrity of the blood-brain barrier after stroke

Integrity of the blood-brain barrier structure is essential for maintaining the internal environment of the brain.Development of cerebral infarction and brain edema is strongly associated with blood-brain barrier leakage.Therefore,studies have suggested that protecting the blood-brain barrier may be an effective method for treating acute stroke.To examine this possibility,stroke model rats were established by middle cerebral artery occlusion and reperfusion.Remote ischemic postconditioning was immediately induced by three cycles of 10-minute ischemia/10-minute reperfusion of bilateral hind limbs at the beginning of middle cerebral artery occlusion reperfusion.Neurological function of rat models was evaluated using Zea Longa’s method.Permeability of the blood-brain barrier was assessed by Evans blue leakage.Infarct volume and brain edema were evaluated using 2,3,5-triphenyltetrazolium chloride staining.Expression of matrix metalloproteinase-9 and claudin-5 m RNA was determined by real-time quantitative reverse transcription-polymerase chain reaction.Expression of matrix metalloproteinase-9 and claudin-5 protein was measured by western blot assay.The number of matrix metalloproteinase-9-and claudin-5-positive cells was analyzed using immunohistochemistry.Our results showed that remote ischemic postconditioning alleviated disruption of the blood-brain barrier,reduced infarct volume and edema,decreased expression of matrix metalloproteinase-9 m RNA and protein and the number of positive cells,increased expression of claudin-5 m RNA and protein and the number of positive cells,and remarkably improved neurological function.These findings confirm that by suppressing expression of matrix metalloproteinase-9 and claudin-5 induced by acute ischemia/reperfusion,remote ischemic postconditioning reduces blood-brain barrier injury,mitigates ischemic injury,and exerts protective effects on the brain.

Electroacupuncture reduces injury to the blood-brain barrier following cerebral ischemia/reperfusion injury

This study used electroacupuncture at Renzhong （DU26） and Baihui （DU20） in a rat model of cerebral ischemia/reperfusion injury. Neurological deficit scores, western blotting, and reverse transcription-PCR results demonstrated that electroacupuncture markedly reduced neurological deficits, decreased corpus striatum aquaporin-4 protein and mRNA expression, and relieved damage to the blood-brain barrier in a rat model of cerebral ischemia/reperfusion injury. These results suggest that electroacupuncture most likely protects the blood-brain barrier by regulating aquaporin-4 expression following cerebral ischemia/reperfusion injury.

CircLphn3 protects the blood-brain barrier in traumatic brain injury

Circular RNAs(circRNAs)are a new and large group of non-coding RNA molecules that are abundantly expressed in the central nervous system.However,very little is known about their roles in traumatic brain injury.In this study,we firstly screened differentially expressed circ RNAs in normal and injured brain tissues of mice after traumatic brain injury.We found that the expression of circ Lphn3 was substantially decreased in mouse models of traumatic brain injury and in hemin-treated b End.3(mouse brain cell line)cells.After overexpressing circ Lphn3 in b End.3 cells,the expression of the tight junction proteins,ZO-1,ZO-2,and occludin,was upregulated,and the expression of mi R-185-5 p was decreased.In b End.3 cells transfected with mi R-185-5 p mimics,the expression of ZO-1 was decreased.Dual-luciferase reporter assays showed that circ Lphn3 bound to mi R-185-5 p,and that mi R-185-5 p bound to ZO-1.Additionally,circ Lphn3 overexpression attenuated the hemin-induced high permeability of the in vitro b End.3 cell model of the blood-brain barrier,while mi R-185-5 p transfection increased the permeability.These findings suggest that circ Lphn3,as a molecular sponge of mi R-185-5 p,regulates tight junction proteins'expression after traumatic brain injury,and it thereby improves the permeability of the blood-brain barrier.This study was approved by the Animal Care and Use Committee of Chongqing Medical University of China(approval No.2021-177)on March 22,2021.

Aquaporin 4 expression and ultrastructure of the blood-brain barrier following cerebral contusion injury

This study aimed to investigate aquaporin 4 expression and the ultrastructure of the blood-brain barrier at 2-72 hours following cerebral contusion injury, and correlate these changes to the formation of brain edema. Results revealed that at 2 hours after cerebral contusion and laceration injury, aquaporin 4 expression significantly increased, brain water content and blood-brain barrier permeability increased, and the number of pinocytotic vesicles in cerebral microvascular endothelia cells increased. In addition, the mitochondrial accumulation was observed. As contusion and laceration injury became aggravated, aquaporin 4 expression continued to increase, brain water content and blood-brain barrier permeability gradually increased, brain capillary endothelial cells and astrocytes swelled, and capillary basement membrane injury gradually increased. The above changes were most apparent at 12 hours after injury, after which they gradually attenuated. Aquaporin 4 expression positively correlated with brain water content and the blood-brain barrier index. Our experimental findings indicate that increasing aquaporin 4 expression and blood-brain barrier permeability after cerebral contusion and laceration injury in humans is involved in the formation of brain edema.

Hyperoside protects the blood-brain barrier from neurotoxicity of amyloid beta 1–42

Mounting evidence indicates that amyloid β protein（Aβ） exerts neurotoxicity by disrupting the blood-brain barrier（BBB） in Alzheimer＇s disease. Hyperoside has neuroprotective effects both in vitro and in vivo against Aβ. Our previous study found that hyperoside suppressed Aβ1-42-induced leakage of the BBB, however, the mechanism remains unclear. In this study, bEnd.3 cells were pretreated with 50, 200, or 500 μM hyperoside for 2 hours, and then exposed to Aβ1-42 for 24 hours. Cell viability was determined using 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl-2-H-tetrazolium bromide assay. Flow cytometry and terminal deoxynucleotidyl transferase-mediated d UTP nick-end labeling assay were used to analyze cell apoptosis. Western blot assay was carried out to analyze expression levels of Bax, Bcl-2, cytochrome c, caspase-3, caspse-8, caspase-9, caspase-12, occludin, claudin-5, zonula occludens-1, matrix metalloproteinase-2（MMP-2）, and MMP-9. Exposure to Aβ1-42 alone remarkably induced bEnd.3 cell apoptosis; increased ratios of cleaved caspase-9/caspase-9, Bax/Bcl-2, cleav ed caspase-8/caspase-8, and cleaved caspase-12/caspase-12; increased expression of cytochrome c and activity of caspase-3; diminished levels of zonula occludens-1, claudin-5, and occludin; and increased levels of MMP-2 and MMP-9. However, hyperoside pretreatment reversed these changes in a dose-dependent manner. Our findings confirm that hyperoside alleviates fibrillar Aβ1-42-induced BBB disruption, thus offering a feasible therapeutic application in Alzheimer＇s disease.

Super Antibiotics, Part II. Hyperforin, Mass Spectroscopy (MS) and Gas Chromatography-Mass Spectrometry (GC-MS), Evidence of Permeability of the Blood-Testis Barrier (BTB) and the Blood-Brain Barrier (BBB) to Hyperforin

In the first article of this series, we presented some evidence of hyperforin as an antibiotic, antiprotozoal, antiviral, anticancer, and immunomodulatory substance. In the present article, evidence of the permeability of the blood-testis barrier (BTB) and blood-brain barrier (BBB) to hyperforin and its distribution in other organs of the domestic pig (Sus scrofa domesticus) are revealed. Seven-month-old male boars with a body mass of 100 kg were fed a diet containing hyperforin. Organs were surgically removed under anesthesia. Organs were suitable prepared and extracted, and then analyzed using gas chromatography-mass spectrometry with supersonic molecular beams (GC-MS with SMB). The presence of hyperforin was recorded in all organs and body fluids. Special attention was paid to the evaluation of the presence of hyperforin in the brain and testes of experimental animals. The presence of hyperforin in the brain and testes of experimental animals was established by GC-MS with SMB. The results are of interest because penicillin and numerous other antibiotics cannot pass through the BTB or BBB if healthy or non-inflamed, which limits their use in patients with meningitis and gonorrhea. The findings are also of interest in cases of penicillin- and multi-antibiotic-resistant bacterial infections.

Non-viral liposome-mediated transfer of brain-derived neurotrophic factor across the blood-brain barrier

Brain-derived neurotrophic factor（BDNF） plays an important role in the repair of central nervous system injury,but cannot directly traverse the blood-brain barrier.Liposomes are a new type of non-viral vector,able to carry macromolecules across the blood-brain barrier and into the brain.Here,we investigate whether BDNF could be transported across the blood-brain barrier by tail-vein injection of liposomes conjugated to transferrin（Tf） and polyethylene glycol（PEG）,and carrying BDNF modified with cytomegalovirus promoter（pC MV） or glial fibrillary acidic protein promoter（p GFAP）（Tf-p CMV-BDNF-PEG and Tf-p GFAP-BDNF-PEG,respectively）.Both liposomes were able to traverse the blood-brain barrier,and BDNF was mainly expressed in the cerebral cortex.BDNF expression in the cerebral cortex was higher in the Tf-p GFAP-BDNF-PEG group than in the Tf-p CMV-BDNF-PEG group.This study demonstrates the successful construction of a non-virus targeted liposome,Tf-p GFAP-BDNF-PEG,which crosses the blood-brain barrier and is distributed in the cerebral cortex.Our work provides an experimental basis for BDNF-related targeted drug delivery in the brain.

The protection effect of compatibility of baicalin and gardenoside on the blood-brain barrier damage

Aim To investigate the protection effect of the compatibility of baicalin and geniposide （7 ： 3 ） on blood-brain barrier （BBB） damage and the mechanism of down-regulating the expression of AQP-4 protein in cere- bral ischemia reperfusion injury （CIRI） rats. Method： 100 rats were divided into 5 groups： sham, CIRI model group, baicalin and geniposide （7 ： 3） （30 mg · kg^-1 ,60 mg · kg^-1） group, allyl chloride （0. 0021 ml· kg^-1）group. The model of CIRI made by improved suture method, Neural function defect, morphology and number of neurons in cerebral cortex was observed by Nissl staining; tested the contental change of P-gp and Na＋ , K＋-ATP enzymes of brain tissue, the contental change of S100β, Glucose, pyruvic acid and lactic acid of plasma by ELISA; the dry wet weight and Evans Blue （EB） tracing method served BBB permeabilitical changes; immunohis- tochemistry staining and semi-quantitation analysis were performed to detect the AQP-4 and GFAP in cerebra ische- mia; the expression of AQP-4 in cerebra hippocampus was determined by RT-qPCR and Western blot; pathological change was observed in brain issueby HE staining; observed the changes of brain tissue ultrastructure usingtrans- mission electron microscope with Lanthanum nitrate tracer ; monitored the size and location of the ischemia injury in brain regions with magnetic resonance imaging （MRI）. Results Compared with CIRI group, baicalin and genipo- side group can restore nerve function defect; increase the number of Nissl positive cells in cerebral cortex; weaken Na＋ ,K＋-ATP enzyme dynamic, reduce the content of S10013 Glucose and P-gp, reduce the content of water and volume EB in brain, elevated the7content of pyruvic acid and pyruvic acid; remarkable attenuation of AQP-4 and GFAP over-expression in the brain; remarkable attenuation of AQP-4 mRNA expression in hippocampus; The mor- phology is became clear, eased lumen of blood vessel compression deformation, loose organization, lessened cell volume and edema; Reduction of lanthanum particles into the blood vessels and the cells, reduce the vascular endo- thelial cell edema. Conclusion Baicalin and geniposide （7 ： 3 ） can reduce the permeability of blood brain barri- er, and has a protective effect on the brain edema induced by CIRI.

Studying Molecular Aspects of the Blood-Brain Barrier Using an in Vitro Model: Contribution of a Global Proteomics Strategy

A global proteomics strategy was initiated to decipher molecular mechanisms associated with the blood-brain barrier (BBB) phenotype of the brain capillary endothelial cells. The different methods implemented were shown complementarily. The main results obtained using an in vitro BBB model allowed highlighting the role of several protein actors of cytoskeleton remodelling, the involvement of the asymmetric dimethylarginine pathway in regulating endothelial function and the role of tissue non-specific alkaline phosphatase in the regulation of endothelial permeability.

Intravenous injection of AAV-PHP.eB across the blood-brain barrier in the adult mouse for central nervous system gene therapy

Objective To verify the neurotypicality of AAV-PHP.eB after tail vein injection in adult mice and its efficiency in crossing the blood-brain barrier(BBB).Methods The rAAV-SYN-GFP plasmid was constructed, and adult C57 BL mice were injected with AAV PHP.eB: SYN-GFP in the tail vein(300 nL, virus titer 3 × 10~9 vg) and in the prefrontal lobe(50 L, virus tite5 × 10^(11) vg). The green fluorescent protein(GFP) signal in the brain was observed at two weeks, while the GFP signal in the peripheral organs was observed at four weeks. Results Two weeks after tail vein injection, GFP expression was observed throughout the brain especially in the cortex, hippocampus, and geniculate nucleus. No GFP signal was observed or detected by western blotting in the peripheral organs after four weeks. GFP signal was observed mainly at the loca site after prefrontal lobe injection.Conclusion AAV-PHP.eB: SYN-GFP can effectively cross the BBB in adult mice. Using a neuron-specific promoter allows exogenous gene expression in neurons; therefore, AAV-PHP.eB can be used as an effective carrier for studying diseases in the central nervous system(CNS).