Transactivating-transduction protein-polyethylene glycol modified liposomes traverse the blood-spinal cord and blood-brain barriers

Naive liposomes can cross the blood-brain barrier and blood-spinal cord barrier in small amounts. Liposomes modified by a transactivating-transduction protein can deliver antibiotics for the treatment of acute bacterial infection-induced brain inflammation. Liposomes conjugated with polyethylene glycol have the capability of long-term circulation. In this study we prepared transactivating-transduction protein-polyethylene glycol-modified liposomes labeled with fiuorescein isothiocyanate. Thus, liposomes were characterized by transmembrane, long-term circulation and fluorescence tracing. Uptake, cytotoxicity, and the ability of traversing blood-spinal cord and blood-brain barriers were observed following coculture with human breast adenocarcinoma cells （MCF-7）. Results demonstrated that the liposomes had good biocompatibility, and low cytotoxicity when cocultured with human breast adenocarcinoma cells. Liposomes could traverse cell membranes and entered the central nervous system and neurocytes through the blood-spinal cord and blood-brain barriers of rats via the systemic circulation. These results verified that fluorescein isothiocyanate-modified transactivating-transduction protein-polyethylene glycol liposomes have the ability to traverse the blood-spinal cord and blood-brain barriers.

Overexpression of mitogen-activated protein kinase phosphatase-1 in endothelial cells reduces blood-brain barrier injury in a mouse model of ischemic stroke

Ischemic stroke can cause blood-brain barrier(BBB)injury,which worsens brain damage induced by stroke.Abnormal expression of tight junction proteins in endothelial cells(ECs)can increase intracellular space and BBB leakage.Selective inhibition of mitogen-activated protein kinase,the negative regulatory substrate of mitogen-activated protein kinase phosphatase(MKP)-1,improves tight junction protein function in ECs,and genetic deletion of MKP-1 aggravates ischemic brain injury.However,whether the latter affects BBB integrity,and the cell type-specific mechanism underlying this process,remain unclear.In this study,we established an adult male mouse model of ischemic stroke by occluding the middle cerebral artery for 60 minutes and overexpressed MKP-1 in ECs on the injured side via lentiviral transfection before stroke.We found that overexpression of MKP-1 in ECs reduced infarct volume,reduced the level of inflammatory factors interleukin-1β,interleukin-6,and chemokine C-C motif ligand-2,inhibited vascular injury,and promoted the recovery of sensorimotor and memory/cognitive function.Overexpression of MKP-1 in ECs also inhibited the activation of cerebral ischemia-induced extracellular signal-regulated kinase(ERK)1/2 and the downregulation of occludin expression.Finally,to investigate the mechanism by which MKP-1 exerted these functions in ECs,we established an ischemic stroke model in vitro by depriving the primary endothelial cell of oxygen and glucose,and pharmacologically inhibited the activity of MKP-1 and ERK1/2.Our findings suggest that MKP-1 inhibition aggravates oxygen and glucose deprivation-induced cell death,cell monolayer leakage,and downregulation of occludin expression,and that inhibiting ERK1/2 can reverse these effects.In addition,co-inhibition of MKP-1 and ERK1/2 exhibited similar effects to inhibition of ERK1/2.These findings suggest that overexpression of MKP-1 in ECs can prevent ischemia-induced occludin downregulation and cell death via deactivating ERK1/2,thereby protecting the integrity of BBB,alleviating brain injury,and improving post-stroke prognosis.

Relationship of gelatinases-tight junction proteins and blood-brain barrier permeability in the early stage of cerebral ischemia and reperfusion

Gelatinases matrix metalloproteinase-2 and matrix metalloproteinase-9 have been shown to mediate claudin-5 and occludin degradation, and play an important regulatory role in blood-brain barrier permeability. This study established a rat model of 1.5-hour middle cerebral artery occlusion with reperfusion. Protein expression levels of claudin-5 and occludin gradually decreased in the early stage of reperfusion, which corresponded to the increase of the gelatinolytic activity of matrix metalloproteinase-2 and matrix metalloproteinase-9. In addition, rats that received treatment with matrix metalloproteinase inhibitor N-[（2R）-2-（hydroxamidocarbonylmethyl）-4-methylpenthanoyl]-L- tryptophan methylamide （GM6001） showed a significant reduction in Evans blue leakage and an inhibition of claudin-5 and occludin protein degradation in striatal tissue. These data indicate that matrix metalloproteinase-2 and matrix metalloproteinase-9-mediated claudin-5 and occludin degradation is an important reason for blood-brain barrier leakage in the early stage of reperfusion. The leakage of the blood-brain barrier was present due to gelatinases-mediated degradation of claudin-5 and occludin proteins. We hypothesized that the timely closure of the structural component of the blood-brain barrier （tight junction proteins） is of importance.

Potential therapeutic molecular targets for blood-brain barrier disruption after subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage remains serious hemorrhagic stroke with high morbidities and mortalities.Aneurysm rupture causes arterial bleeding-induced mechanical brain tissue injuries and elevated intracranial pressure,followed by global cerebral ischemia.Post-subarachnoid hemorrhage ischemia,tissue injuries as well as extravasated blood components and the breakdown products activate microglia,astrocytes and Toll-like receptor 4,and disrupt blood-brain barrier associated with the induction of many inflammatory and other cascades.Once blood-brain barrier is disrupted,brain tissues are directly exposed to harmful blood contents and immune cells,which aggravate brain injuries furthermore.Blood-brain barrier disruption after subarachnoid hemorrhage may be developed by a variety of mechanisms including endothelial cell apoptosis and disruption of tight junction proteins.Many molecules and pathways have been reported to disrupt the blood-brain barrier after subarachnoid hemorrhage,but the exact mechanisms remain unclear.Multiple independent and/or interconnected signaling pathways may be involved in blood-brain barrier disruption after subarachnoid hemorrhage.This review provides recent understandings of the mechanisms and the potential therapeutic targets of blood-brain barrier disruption after subarachnoid hemorrhage.

Urolithin A alleviates blood-brain barrier disruption and attenuates neuronal apoptosis following traumatic brain injury in mice

Urolithin A(UA)is a natural metabolite produced from polyphenolics in foods such as pomegranates,berries,and nuts.UA is neuroprotective against Parkinson’s disease,Alzheimer’s disease,and cerebral hemorrhage.However,its effect against traumatic brain injury remains unknown.In this study,we established adult C57BL/6J mouse models of traumatic brain injury by controlled cortical impact and then intraperitoneally administered UA.We found that UA greatly reduced brain edema;increased the expression of tight junction proteins in injured cortex;increased the immunopositivity of two neuronal autophagy markers,microtubule-associated protein 1A/B light chain 3A/B(LC3)and p62;downregulated protein kinase B(Akt)and mammalian target of rapamycin(mTOR),two regulators of the phosphatidylinositol 3-kinase(PI3K)/Akt/mTOR signaling pathway;decreased the phosphorylation levels of inhibitor of NFκB(IκB)kinase alpha(IKKα)and nuclear factor kappa B(NFκB),two regulators of the neuroinflammation-related Akt/IKK/NFκB signaling pathway;reduced blood-brain barrier permeability and neuronal apoptosis in injured cortex;and improved mouse neurological function.These findings suggest that UA may be a candidate drug for the treatment of traumatic brain injury,and its neuroprotective effects may be mediated by inhibition of the PI3K/Akt/mTOR and Akt/IKK/NFκB signaling pathways,thus reducing neuroinflammation and enhancing autophagy.

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.

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.

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.

Changes in blood-brain barrier permeability and expression of related factors in a rat model of intracerebral hemorrhage following minocycline treatment

Inflammatory factor aggregation and blood-brain barrier（BBB）damage occur around hematoma foci following intracerebral hemorrhage.Minocycline is lipophilic,can pass through the BBB,and shows anti-inflammatory effects in models of central nervous system disease.We found that minocycline application at 6 hours after intracerebral hemorrhage reduced BBB permeability,decreased vascular endothelial growth factor expression,and increased nerve growth factor and heat shock protein 70 expression,primarily in neurons and microglia.Early intraperitoneal injection of minocycline attenuated BBB damage possibly by reducing vascular endothelial growth factor expression and enhancing nerve growth factor and heat shock protein 70 expression.

Upregulated inflammatory associated factors and blood-retinal barrier changes in the retina of type 2diabetes mellitus model

AIM： To examine the expression of high mobility group box-1（HMGB-1） and intercellular adhesion molecule-1（ICAM-1） in the retina and the hippocampal tissues; and further to evaluate the association of these two molecules with the alterations of blood-retinal barrier（BRB） and blood-brain barrier（BBB） in a rat model of type 2 diabetes.METHODS： The type-2 diabetes mellitus（DM） model was established with a high-fat and high-glucose diet combined with streptozotocin（STZ）. Sixteen weeks after DM induction, morphological changes of retina and hippocampus were observed with hematoxylin-eosin staining, and alternations of BRB and BBB permeability were measured using Evans blue method. Levels of HMGB-1 and ICAM-1 in retina and hippocampus were detected by Western blot. Serum HMGB-1 levels were determined by enzyme-linked immunosorbent assay（ELISA）.RESULTS： A significantly higher serum fasting blood glucose level in DM rats was observed 2wk after STZ injection（P 〈0.01）. The serum levels of fasting insulin,Insulin resistance homeostatic model assessment（IRHOMA）,total cholesterol（TC）, total triglycerides（TG） and low density lipoprotein cholesterol（LDL-C） in the DM rats significantly higher than those in the controls（all P 〈0.01）.HMGB-1（0.96±0.03, P 〈0.01） and ICAM-1（0.76±0.12, P 〈0.05） levels in the retina in the DM rats were significantly higher than those in the controls. HMGB-1（0.83±0.13, P 〈0.01） and ICAM-1（1.15 ±0.08, P 〈0.01） levels in the hippocampal tissues in the DM rats were alsosignificantly higher than those in the controls. Sixteen weeks after induction of DM, the BRB permeability to albumin-bound Evans blue dye in the DM rats was significantly higher than that in the controls（P 〈0.01）.However, there was no difference of BBB permeability between the DM rats and controls. When compared to the controls, hematoxylin and eosin staining showed obvious irregularities in the DM rats.CONCLUSION： BRB permeability increases significantly in rats with type-2 DM, which may be associated with the up-regulated retinal expression of HMGB-1 and ICAM-1.

Relationship between serum S-100 protein level and ischemic damage degree in patients with acute cerebral infarction

Objective: To investigate the time course of serum S-100 concentrations of patients with acute cerebral infarction,and their relation with the clinical data and the prognosis. Methods: Serum S-100 levels were serially determined in 36 patients with acute cerebral infarction within 12 h, at 24 h and day 2, 3, 4, 5, 7 and 10 after acute cerebral infarction and in 20 age- and sex-matched control subjects. An S-100 content assay was performed using a two-site radioimmunoassay technique. The clinical status was assessed using NIH Stroke Scale. The functional deficit at 4 weeks after acute cerebral infarction was scored using the modified Rankin scale. A cranial computed tomography was performed initially. Results: Elevated concentrations of S-100 (>0.2 μg/L) were observed in 29 of 36 patients with acute cerebral infarction,but none of the control subjects. The S-100 peak levels were at day 2 and 3 after acute cerebral infarction and were significantly high in those patients with severe neurological deficit at admission, with extensive infarction or with space-occupying effect of ischemic edema as compared with the rest of the populations. Conclusion: Serum S-100 level assay can be used as a peripheral marker of ischemic brain damage, and may be helpful for evaluation of therapeutic effects in acute ischemic stroke.

Self-Assembly Protein Superstructures as a Powerful Chemodynamic Therapy Nanoagent for Glioblastoma Treatment

Glioblastoma(GBM) remains a formidable challenge in oncology.Chemodynamic therapy(CDT) that triggers tumor cell death by reactive oxygen species(ROS) could open up a new door for GBM treatment.Herein,we report a novel CDT nanoagent.Hemoglobin(Hb)and glucose oxidase(GOx) were employed as powerful CDT catalysts.Instead of encapsulating the proteins in drug delivery nanocarriers,we formulate multimeric superstructures as self-delivery entities by crosslinking techniques.Red blood cell(RBC) membranes are camouflaged on the protein superstructures to promote the delivery across blood-brain barrier.The as-prepared RBC@Hb@GOx nanoparticles(NPs) offer superior biocompatibility,simplified structure,and high accumulation at the tumor site.We successfully demonstrated that the NPs could efficiently produce toxic ROS to kill U87 MG cancer cells in vitro and inhibit the growth of GBM tumor in vivo,suggesting that the new CDT nanoagent holds great promise for treating GBM.

Protocadherin gamma C3:a new player in regulating vascular barrier function

Defects in the endothelial cell barrier accompany diverse malfunctions of the central nervous system such as neurodegenerative diseases,stroke,traumatic brain injury,and systemic diseases such as sepsis,viral and bacterial infections,and cancer.Compromised endothelial sealing leads to leaking blood vessels,followed by vasogenic edema.Brain edema as the most common complication caused by stroke and traumatic brain injury is the leading cause of death.Brain microvascular endothelial cells,together with astrocytes,pericytes,microglia,and neurons form a selective barrier,the so-called blood-brain barrier,which regulates the movement of molecules inside and outside of the brain.Mechanisms that regulate blood-brain barrier permeability in health and disease are complex and not fully understood.Several newly discovered molecules that are involved in the regulation of cellular processes in brain microvascular endothelial cells have been described in the literature in recent years.One of these molecules that are highly expressed in brain microvascular endothelial cells is protocadherin gamma C3.In this review,we discuss recent evidence that protocadherin gamma C3 is a newly identified key player involved in the regulation of vascular barrier function.

Biomedical Applications of Single Protein Nanoparticles

The drug carrier function of single protein nanoparticles, i.e., each individual protein molecule covered by a very thin, porous and few nanometer thick polymer layer, has been investigated. This layer around protein molecule is very thin, about 3-5 nm thick and highly porous, thus it does not reduce seriously the enzymatic function of protein molecule. The spatial structure of encapsulated protein molecule, which is essential in its function, can be stabilized by this polymer layer. Bovine serum albumin was used as protein drug molecule and it was encapsulated with acrylamide-bisarylamide random copolymer. The polymerization, starting from the modified sites of the surface of bovine serum albumin molecules was initiated by TEMED （tetramethylethylenediamine）. These single albumin nanoparticles were painted with fluorescein isothiocyanate. This material was then injected into the inferior vena cava of rats. The treated rats were decapitated after 1 to 10 minutes and its brain was investigated by fluorescent microscopy. It was proved that bovine serum albumin molecules as drugs encapsulated in polymer nano-layer with a reduced size （about 10 nm） can pass through the blood brain barrier. The results suggest that this method is capable of transformation of biomacromolecules to access the brain tissue via the blood.

Engineering blood-brain barrier-permeable and tumor cell-ingestible pro-proteins for glioblastoma treatment

Intracellular protein therapeutics holds great potentials for the treatment of glioblastoma, which however, is greatly challenged by the unmet demands to concomitantly penetrate the blood-brain barrier(BBB) and glioblastoma cell membrane barrier with high efficiency and selectivity. Herein, a unique pro-protein platform was developed via facile green synthesis, which allowed efficient and selective delivery into glioblastoma cells in a carrier-free manner. Pro-proteins were engineered via reversible modification of native proteins in the aqueous buffer with 3,4-dihydroxy-phenylalanine, the substrate of L-type amino acid transporter(LAT1), bridged with a phenylboronic acid-containing linker. By harnessing the LAT1-mediated direct transport mechanism, the optimized pro-protein, named protein-M2-D, can efficiently penetrate BBB after i.v. injection, and subsequently enable selective and endocytosis-free delivery of various proteins including enzymes, toxins, and antibodies into glioblastoma cells, wherein intracellular H_(2)O_(2) triggered traceless restoration of the native protein structure. Systemic administration of saporin-M2-D provoked potent anti-tumor efficacy against orthotopic U87 glioblastoma in mice, without inducing systemic toxicity. Such a facile, versatile, and robust platform renders a promising paradigm for cytosolic protein delivery and glioblastoma treatment.

Dexmedetomidine attenuates traumatic brain injury: action pathway and mechanisms

Traumatic brain injury induces potent inflammatory responses that can exacerbate secondary blood-brain barrier（BBB） disruption, neuronal injury, and neurological dysfunction. Dexmedetomidine is a novel α2-adrenergic receptor agonist that exert protective effects in various central nervous system diseases. The present study was designed to investigate the neuroprotective action of dexmedetomidine in a mouse traumatic brain injury model, and to explore the possible mechanisms. Adult male C57 BL/6 J mice were subjected to controlled cortical impact. After injury, animals received 3 days of consecutive dexmedetomidine therapy（25 μg/kg per day）. The modified neurological severity score was used to assess neurological deficits. The rotarod test was used to evaluate accurate motor coordination and balance. Immunofluorescence was used to determine expression of ionized calcium binding adapter molecule-1, myeloperoxidase, and zonula occluden-1 at the injury site. An enzyme linked immunosorbent assay was used to measure the concentration of interleukin-1β（IL-1β）, tumor necrosis factor α, and IL-6. The dry-wet weight method was used to measure brain water content. The Evans blue dye extravasation assay was used to measure BBB disruption. Western blot assay was used to measure protein expression of nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3（NLRP3）, caspase-1 p20, IL-1β, nuclear factor kappa B（NF-κB） p65, occluding, and zonula occluden-1. Flow cytometry was used to measure cellular apoptosis. Results showed that dexmedetomidine treatment attenuated early neurological dysfunction and brain edema. Further, dexmedetomidine attenuated post-traumatic inflammation, up-regulated tight junction protein expression, and reduced secondary BBB damage and apoptosis. These protective effects were accompanied by down-regulation of the NF-κB and NLRP3 inflammasome pathways. These findings suggest that dexmedetomidine exhibits neuroprotective effects against acute（3 days） post-traumatic inflammatory responses, potentially via suppression of NF-κB and NLRP3 inflammasome activation.

Shuxuetong injection protects cerebral microvascular endothelial cells against oxygen-glucose deprivation reperfusion

Shuxuetong injection composed of leech(Hirudo nipponica Whitman) and earthworm(Pheretima aspergillum) has been used for the clinical treatment of acute stroke for many years in China. However, the precise neuroprotective mechanism of Shuxuetong injection remains poorly understood. Here, cerebral microvascular endothelial cells(bEnd.3) were incubated in glucose-free Dulbecco's modified Eagle's medium containing 95% N_2/5% CO_2 for 6 hours, followed by high-glucose medium containing 95% O_2 and 5% CO_2 for 18 hours to establish an oxygen-glucose deprivation/reperfusion model. This in vitro cell model was administered Shuxuetong injection at 1/32, 1/64, and 1/128 concentrations(diluted 32-, 64-, and 128-times). Cell Counting Kit-8 assay was used to evaluate cell viability. A fluorescence method was used to measure lactate dehydrogenase, and a fluorescence microplate reader used to detect intracellular reactive oxygen species. A fluorescent probe was also used to measure mitochondrial superoxide production. A cell resistance meter was used to measure transepithelial resistance and examine integrity of monolayer cells. The fluorescein isothiocyanate-dextran test was performed to examine blood-brain barrier permeability. Real-time reverse transcription polymerase chain reaction was performed to analyze mRNA expression levels of tumor necrosis factor alpha, interleukin-1β, interleukin-6, and inducible nitric oxide synthase. Western blot assay was performed to analyze expression of caspase-3, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, occludin, vascular endothelial growth factor, cleaved caspase-3, B-cell lymphoma 2, phosphorylated extracellular signal-regulated protein kinase, extracellular signal-regulated protein kinase, nuclear factor-κB p65, I kappa B alpha, phosphorylated I kappa B alpha, I kappa B kinase, phosphorylated I kappa B kinase, claudin-5, and zonula occludens-1. Our results show that Shuxuetong injection increases bEnd.3 cell viability and B-cell lymphoma 2 expression, reduces cleaved caspase-3 expression, inhibits production of reactive oxygen species and mitochondrial superoxide, suppresses expression of tumor necrosis factor alpha, interleukin-1β, interleukin-6, inducible nitric oxide synthase mRNA, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1, markedly increases transepithelial resistance, decreases blood-brain barrier permeability, upregulates claudin-5, occludin, and zonula occludens-1 expression, reduces nuclear factor-κB p65 and vascular endothelial growth factor expression, and reduces I kappa B alpha, extracellular signal-regulated protein kinase 1/2, and I kappa B kinase phosphorylation levels. Overall, these findings suggest that Shuxuetong injection has protective effects on brain microvascular endothelial cells after oxygen-glucose deprivation/reperfusion. Moreover, its protective effect is associated with reduction of mitochondrial superoxide production, inhibition of the inflammatory response, and inhibition of vascular endothelial growth factor, extracellular signal-regulated protein kinase 1/2, and the nuclear factor-κB p65 signaling pathway.

Knockout of Sirt2 alleviates traumatic brain injury in mice

Sirtuin 2(SIRT2)inhibition or Sirt2 knocko ut in animal models protects against the development of neurodegenerative diseases and cerebral ischemia.However,the role of SIRT2 in traumatic brain injury(TBI)remains unclear.In this study,we found that knockout of Sirt2 in a mouse model of TBI reduced brain edema,attenuated dis ruption of the blood-brain barrie r,decreased expression of the nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome,reduced the activity of the effector caspase-1,reduced neuroinflammation and neuronal pyroptosis,and improved neurological function.Knoc kout of Sirt2 in a mechanical stretch injury cell model in vitro also decreased expression of the NLRP3 inflammasome and pyroptosis.Our findings suggest that knockout of Sirt2 is neuro protective against TBI;therefore.Sirt2 could be a novel to rget for TBI treatment.

TIMP1 preserves the blood-brain barrier through interacting with CD63/integrin β1 complex and regulating downstream FAK/RhoA signaling

Blood-brain barrier(BBB)breakdown and the associated microvascular hyperpermeability are hallmark features of several neurological disorders,including traumatic brain injury(TBI).However,there is no viable therapeutic strategy to rescue BBB function.Tissue inhibitor of metalloproteinase-1(TIMP1)has been considered to be beneficial for vascular integrity,but the molecular mechanisms underlying the functions of TIMP1 remain elusive.Here,we report that TIMP1 executes a protective role on neuroprotective function via ameliorating BBB disruption in mice with experimental TBI.In human brain microvessel endothelial cells(HBMECs)exposed to hypoxia and inflammation injury,the recombinant TIMP1(rTIMP1)treatment maintained integrity of junctional proteins and trans-endothelial tightness.Mechanistically,TIMP1 interacts with CD63/integrinβ1 complex and activates downstream FAK signaling,leading to attenuation of RhoA activation and F-actin depolymerization for endothelial cells structure stabilization.Notably,these effects depend on CD63/integrinβ1 complex,instead of the MMP-inhibitory function.Together,our results identified a novel MMP-independent function of TIMP1 in regulating endothelial barrier integrity.Therapeutic interventions targeting TIMP1 and its downstream signaling may be beneficial to protect BBB function following brain injury and neurological disorders.

CT血流灌注结合血脑屏障标志蛋白对中毒性休克患者神经元损伤的评价价值

选择2017年12月~2018年11月我院收治的100例经临床确认的中毒性休克患者的临床资料,所有患者均进行CT血流灌注成像检查,原始图像经工作站自带的脑灌注软件处理后产生灌注参数伪彩图像,测量病变侧及对侧大脑半球多个解剖部位的脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)、达峰时间(TTP)等灌注参数,计算病变侧/对侧的对比值(rCBF、rCBV、rMTT、rTTP)。并使用免疫组学方法检测不同患者外周血及脑脊液中血脑屏障通透性与紧密连接蛋白claudin-5、occludin、ZO-1、JAM-1、NOS和NSE的表达水平变化,并比较灌注参数与血脑屏障标志蛋白水平的相关性。结果显示,观察组患者外周血及脑脊液rCBF显著下降,rTTP降低,rPS升高(P<0.05),但两组rMTT、rCBV比较,差异无统计学意义(P>0.05)。观察组患者外周血及脑脊液claudin-5、occludin、ZO-1、NOS显著下降,JAM-1、NSE明显升高(P<0.05)。观察组claudin-5、occludin、ZO-1和NOS与rCBF、rTTP呈正相关,与rPS呈负相关;JAM-1和NSE与rCBF、rTTP呈负相关,与rPS呈正相关。rCBF、rTTP、JAM-1、NSE与神经元损伤程度呈正相关,claudin-5、occludin、ZO-1和NOS与神经元损伤程度呈负相关。上述结果表明CT血流灌注参数结合血脑屏障标志蛋白可有效评估中毒性休克患者神经元损伤程度,值得推广和应用。