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1.
J Pharmacol Sci ; 145(1): 155-165, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33357774

RESUMEN

In this study, among neurovascular unit (NVU) cells, we focused on pericyte reactivity in mice subjected to controlled cortical impact (CCI) to understand how traumatic brain injury (TBI) causes uncoordinated crosstalk in the NVU and alters neuronal activity. Histological analyses of brain pericytes, microglia and astrocytes were performed for up to 28 days after CCI in the injured ipsilateral hippocampus. To evaluate altered neuronal activity caused by CCI, we measured seizure susceptibility to a sub-threshold dose of pilocarpine on postoperative day 7, 14, 21 and 28. Platelet-derived growth factor receptor (PDGFR) ß immunoreactivity in pericytes significantly increased from 1 h to 4 days after CCI. The expression of Iba1 and GFAP, as markers of microglia and astrocytes, respectively, increased from 4 to 28 days after CCI. The severity of seizure induced by pilocarpine gradually increased, becoming significant at 28 days after CCI. Then, we treated CCI mice with an inhibitor of PDGFR signaling, imatinib, during the postoperative day 0-4 period. Imatinib lowered seizure susceptibility to pilocarpine and suppressed microglial activation in the injured hippocampus at postoperative day 28. These findings indicate that brain pericytes with rapidly increased PDGFRß expression may drive TBI-induced dysregulation of NVU function and brain hyperexcitability.

2.
Neurosci Lett ; 738: 135352, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-32931862

RESUMEN

The blood-brain barrier (BBB) is the multicellular interface located between the peripheral circulation and the brain parenchyma. BBB dysfunction is reported in many CNS diseases, such cognitive impairment, depression, Alzheimer's disease (AD), and multiple sclerosis (MS). Emerging evidence indicates that liver-derived inflammatory mediators are upregulated in neurological diseases with BBB dysfunction. Serum amyloid A (SAA), an acute phase protein secreted by hepatocytes, could be a candidate inflammatory signaling molecule transmitted from the liver to the brain; however, its contribution to BBB dysfunction is poorly understood. The present study aimed to elucidate the involvement of SAA in BBB impairment in an in vitro BBB model using rat brain microvascular endothelial cells (RBECs). We demonstrated that Apo-SAA significantly decreased transendothelial electrical resistance (TEER) and increased sodium fluorescein (Na-F) permeability in RBEC monolayers. Apo-SAA also decreased claudin-5 expression levels in RBECs. Furthermore, the Apo-SAA-mediated impairment of the BBB with decreased claudin-5 expression was inhibited by the addition of a high-density lipoprotein (HDL) related to SAA in plasma. These findings suggest that HDL counteracts the effects of SAA on BBB function. Therefore, the functional imbalance between SAA and HDL may induce BBB impairment, thereby triggering development of neuroinflammation. SAA could be a significant endogenous mediator in the liver-to-brain inflammation axis.

3.
NPJ Sci Food ; 4: 7, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32377566

RESUMEN

In this study, experiments on amyloid ß peptide25-35-induced mice were performed to provide in vivo evidence on the potential of the blood-brain barrier transportable soy dipeptide, Tyr-Pro, in combating memory impairment. We demonstrated for the first time that oral administration of Tyr-Pro (100 mg/kg, twice a day) in mice for 16 days significantly improved impaired memory by spontaneous alternation and shortened step-through latency in amyloid ß-induced mice.

4.
Neurosci Lett ; 715: 134594, 2020 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-31678431

RESUMEN

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.

5.
Neuroscience ; 422: 12-20, 2019 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-31705893

RESUMEN

Oncostatin M (OSM) is a cytokine of the interleukin (IL)-6 family members. It induces blood-brain barrier (BBB) dysfunction by activating Janus-activated kinase (JAK) and signal transducer and activator of transcription (STAT) 3 pathways in brain endothelial cells. Brain pericytes located around microvessels are one of the BBB constituents. Pericytes work as a boundary surface between the blood circulation and brain parenchyma, and their functions are altered under pathophysiological conditions, leading to BBB dysregulation. However, it remains unknown whether pericytes are associated with OSM-induced BBB dysfunction. We demonstrated that pericyte exposure to OSM (100 ng/mL) elevated phosphorylation of STAT3, a main OSM signaling pathway, and that pericytes expressed OSM receptors (OSMRs) including OSMRß and glycoprotein 130. These results suggest that pericytes are able to respond to OSM. To determine the effects of OSM-reactive pericytes on BBB functions, rat brain endothelial cell (RBEC) monolayers were cultured with OSM-treated pericytes. The presence of pericytes exposed to 100 ng/mL of OSM for 48 h aggravated both the elevated permeability to sodium fluorescein and the lowered transendothelial electrical resistance which were induced by OSM in RBECs. This OSM-reactive pericyte-induced aggravation of lowered RBEC barrier function was reversed by ruxolitinib, a JAK inhibitor. These findings suggest that activated JAK/STAT3 signaling in pericytes contributes to OSM-produced BBB breakdown. Thus, OSM-reactive pericytes may have to be considered a characteristic machinery in the formation and progression of BBB breakdown under pathological conditions associated with increased OSM levels.


Asunto(s)
Barrera Hematoencefálica/fisiopatología , Quinasas Janus/metabolismo , Oncostatina M/farmacología , Oncostatina M/fisiología , Factor de Transcripción STAT3/metabolismo , Animales , Receptor gp130 de Citocinas/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Oncostatina M/antagonistas & inhibidores , Subunidad beta del Receptor de Oncostatina M/metabolismo , Pericitos/efectos de los fármacos , Pericitos/metabolismo , Fosforilación/efectos de los fármacos , Cultivo Primario de Células , Pirazoles/farmacología , Ratas , Transducción de Señal
6.
Cerebrovasc Dis Extra ; 9(1): 25-30, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31039570

RESUMEN

BACKGROUND/PURPOSE: Because atherosclerotic factors and antithrombotic agents sometimes induce cerebral microbleeds (CMBs), patients with cerebral large artery disease (CLAD) tend to have more CMBs than control subjects. On the other hand, VEGF contributes to the disruption of the blood-brain barrier, and it may induce parenchymal edema and bleeding. We conducted a study to evaluate the role of vascular endothelial growth factor (VEGF) in the occurrence of CMBs in patients with CLAD. METHODS: CLAD is defined as stenosis or occlusion of either the carotid artery or the middle cerebral artery of 50% or more. We prospectively registered patients with CLAD who were hospitalized in our neurocenter. Biological backgrounds, atherosclerotic risk factors, administration of antithrombotics before hospitalization, and levels of cytokines and chemokines were evaluated. Susceptibility-weighted imaging or T2*-weighted MR angiography was used to evaluate CMBs. The Brain Observer MicroBleed Scale (BOMBS) was used for CMB assessments. Images were analyzed with regard to the presence or absence of CMBs. We also examined plasma VEGF concentrations using a commercial ELISA kit. Because more than half showed plasma VEGF levels below assay detection limits (3.2 pg/mL), the patients were dichotomized by plasma VEGF levels into two groups (above and below the detection limit). After univariate analyses, logistic regression analysis was conducted to determine the factors associated with the CMBs after adjustment for age, sex, the presence of hypertension, and administration of antithrombotic agents. A similar analysis with CMBs separated by location (cortex, subcortex, or posterior circulation) was also conducted. RESULTS: Sixty-six patients (71.1 ± 8.9 years, 53 males and 13 females) were included in this study. Plasma VEGF levels were not correlated with age, sex, and atherosclerotic risk factors; however, patients with VEGF levels >3.2 pg/mL tended toward more frequent CMBs (60.0 vs. 32.6%, in the presence and absence of CMBs, p = 0.056). With regard to the location of CMBs, those in the cortex and/or at the gray-white junction were observed more frequently in the patients with VEGF levels >3.2 pg/mL after multivariable analyses (odds ratio: 3.80; 95% confidence interval: 1.07-13.5; p = 0.039). CONCLUSIONS: In patients with CLAD, elevated plasma VEGF might be associated with CMBs, especially those located in the cortex and/or at the gray-white junction.


Asunto(s)
Estenosis Carotídea/sangre , Enfermedades Arteriales Cerebrales/sangre , Hemorragia Cerebral/sangre , Factor A de Crecimiento Endotelial Vascular/sangre , Anciano , Anciano de 80 o más Años , Biomarcadores/sangre , Estenosis Carotídea/complicaciones , Estenosis Carotídea/diagnóstico por imagen , Angiografía Cerebral/métodos , Enfermedades Arteriales Cerebrales/complicaciones , Enfermedades Arteriales Cerebrales/diagnóstico por imagen , Hemorragia Cerebral/diagnóstico por imagen , Hemorragia Cerebral/etiología , Imagen de Difusión por Resonancia Magnética , Femenino , Humanos , Angiografía por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Regulación hacia Arriba
7.
Sci Rep ; 9(1): 5769, 2019 04 08.
Artículo en Inglés | MEDLINE | ID: mdl-30962462

RESUMEN

Apart from nutrients required for the brain, there has been no report that naturally occurring peptides can cross the blood-brain barrier (BBB). The aim of this study was to identify the BBB-transportable peptides using in situ mouse perfusion experiments. Based on the structural features of Gly-N-methylated Gly (Gly-Sar), a reported BBB-transportable compound, 18 dipeptides were synthesized, and were perfused in the mouse brain for two minutes. Among the synthesized dipeptides, Gly-Sar, Gly-Pro, and Tyr-Pro were transported across the BBB with Ki values of 7.60 ± 1.29, 3.49 ± 0.66, and 3.53 ± 0.74 µL/g·min, respectively, and accumulated in the mouse brain parenchyma. Additionally, using MALDI-MS/MS imaging analysis of Tyr-Pro-perfused brain, we provide evidence for Tyr-Pro accumulation in the hippocampus, hypothalamus, striatum, cerebral cortex, and cerebellum of mouse brain.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Dipéptidos/farmacocinética , Animales , Cerebelo/metabolismo , Corteza Cerebral/metabolismo , Dipéptidos/química , Hipocampo/metabolismo , Hipotálamo/metabolismo , Masculino , Ratones , Ratones Endogámicos ICR , Distribución Tisular
8.
Microvasc Res ; 124: 61-66, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30885616

RESUMEN

Blood-brain barrier (BBB) disruption is often mediated by neuroinflammation, and occurs during various neurodegenerative diseases including Parkinson's disease (PD). PD is characterized by loss of dopaminergic neurons and aggregated α-synuclein protein in inclusions known as Lewy bodies. Misfolded α-synuclein has been implicated in neurodegeneration and neuroinflammation through activation of microglia and astrocytes. Pericytes are a key cellular regulator of the BBB, although it is not known if they participate in α-synuclein-associated PD pathology. Here, we investigated the impact of pericytes on BBB integrity in response to α-synuclein using rat brain endothelial cells (RBECs) co-cultured with rat brain pericytes (RBEC/pericyte co-culture). In RBEC/pericyte co-cultures, α-synuclein added to the abluminal chamber (where pericytes were grown) significantly increased RBEC permeability to sodium fluorescein. In contrast, it had no marked effect when added to the luminal chamber. In the absence of pericytes, both luminal and abluminal addition of α-synuclein failed to affect permeability of the RBEC monolayer. α-Synuclein did not self-assemble in culture media within 24 h, suggesting that monomeric α-synuclein can disrupt the BBB by interacting with pericytes. We found that in response to α-synuclein, pericytes, but not RBECs, released interleukin (IL)-1ß, IL-6, monocyte chemotactic protein (MCP)-1, tumor necrosis factor (TNF)-α, and matrix metalloproteinase-9 (MMP-9). α-Synuclein did not affect platelet-derived growth factor (PDGF)-BB release from RBECs and PDGF receptor-ß expression in pericytes. These results suggest that pericytes are more sensitive to monomeric α-synuclein than RBECs regarding release of various inflammatory cytokines/chemokines and MMP-9. Thus, monomeric α-synuclein-activated pericytes may contribute to BBB breakdown in patients with PD.


Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Mediadores de Inflamación/metabolismo , Pericitos/efectos de los fármacos , alfa-Sinucleína/farmacología , Animales , Barrera Hematoencefálica/metabolismo , Permeabilidad Capilar/efectos de los fármacos , Células Cultivadas , Quimiocina CCL2/metabolismo , Técnicas de Cocultivo , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Femenino , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Pericitos/metabolismo , Ratas Wistar , Factor de Necrosis Tumoral alfa/metabolismo
9.
Anal Sci ; 35(4): 433-439, 2019 Apr 10.
Artículo en Inglés | MEDLINE | ID: mdl-30584183

RESUMEN

In this study, a simultaneous assay for catecholamines and their metabolites in the brain was established using liquid chromatography-mass spectrometry (LC-MS). To achieve complete separation, a cation-exchange/reversed-phase mixed-mode copolymer resin column containing 0.81 wt% sulfo groups was used for the simultaneous LC-MS assay. The analyzed catecholamines were dopamine (DA), norepinephrine (NE), and epinephrine (E), while the metabolites lacking amino groups were 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG). The metabolites were separated and detected using LC-MS, on columns with and without sulfo groups. However, we could not achieve adequate separation of catecholamines on both columns using a gradient elution of 0 - 50 (v/v)% methanol containing 0.1 (v/v)% formic acid (FA). When volatile ion-pairing reagents were added to the mobile phase, they improved the retention and detection of catecholamines on the sulfonated mixed-mode column. Under optimized elution conditions, which involved a linear gradient elution of water containing 0.1 (v/v)% FA to 50 (v/v)% acetonitrile in 50 mM ammonium formate at 40°C and a 0.20 mL/min rate, all six target molecules were simultaneously detected within 25 min, when using negative mode LC-MS on a sulfonated mixed-mode column. The limits of detection (LODs) for DA, NE, E, DOPCA, HVA, and MHPG were determined to be 20.7, 12.6, 74.6, 1110, 18.7, and 3196 nM, respectively. Moreover, the established LC-MS assay allowed the detection of endogenous DA, NE, and HVA, in normal mouse brain samples at concentrations higher than 20, 9, and 4 pmol/mg, respectively.


Asunto(s)
Ácido 3,4-Dihidroxifenilacético/análisis , Encéfalo/metabolismo , Catecolaminas/análisis , Glicoles de Etileno/análisis , Ácido Homovanílico/análisis , Fenoles/análisis , Polímeros/química , Ácido 3,4-Dihidroxifenilacético/metabolismo , Animales , Catecolaminas/metabolismo , Cromatografía Líquida de Alta Presión , Glicoles de Etileno/metabolismo , Ácido Homovanílico/metabolismo , Masculino , Espectrometría de Masas , Ratones , Ratones Endogámicos ICR , Fenoles/metabolismo , Ácidos Sulfónicos/química
10.
Behav Pharmacol ; 30(1): 89-94, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-29847340

RESUMEN

The development of Parkinson's disease (PD) involves the degeneration of dopaminergic neurons caused by oxidative stress. Accumulating clinical evidence indicates that high blood levels of uric acid (UA), an intrinsic antioxidative substance, are associated with reduced risk of PD. However, this hypothesis has not been confirmed by in-vivo experiments. The present study investigated the effects of UA on behavioral abnormalities in the development of PD. We used unilateral 6-hydroxydopamine-lesioned mice, which were fed on a diet containing 1% UA and 2.5% potassium oxonate (an uricase inhibitor) to induce hyperuricemia. A significant elevation in UA levels was found in groups that were fed a UA diet. The 6-hydroxydopamine-lesioned mice showed impaired rotarod performance and increased apomorphine-induced contralateral rotations. These behavioral abnormalities were significantly reversed by feeding a UA diet for 1 week before and 5 weeks after surgery (subchronic hyperuricemia). These behavioral improvements occurred in parallel with recovery of tyrosine hydroxylase protein levels in the lesioned striatal side. The present study with a dietary hyperuricemia mice model confirms that UA exerts a neuroprotective effect on dopaminergic neuronal loss, improving motor dysfunction and ameliorating PD development.


Asunto(s)
Trastornos Mentales/sangre , Trastornos Mentales/etiología , Enfermedad de Parkinson Secundaria/complicaciones , Ácido Úrico/sangre , Adrenérgicos/toxicidad , Animales , Apomorfina/farmacología , Modelos Animales de Enfermedad , Hiperuricemia/sangre , Hiperuricemia/etiología , Masculino , Trastornos Mentales/dietoterapia , Ratones , Ratones Endogámicos ICR , Actividad Motora/efectos de los fármacos , Oxidopamina/toxicidad , Ácido Oxónico/administración & dosificación , Enfermedad de Parkinson Secundaria/inducido químicamente , Prueba de Desempeño de Rotación con Aceleración Constante , Tirosina 3-Monooxigenasa/metabolismo
11.
Neurosci Lett ; 694: 9-13, 2019 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-30452951

RESUMEN

The blood-brain barrier (BBB) is formed by brain endothelial cells (BECs) and regulates brain homeostasis by restricting the entry of blood-borne substances into the brain. Recent in vivo studies have shown that administration of nicotinic acetylcholine receptor (nAChR) agonists protects against BBB disruption and neuroinflammation induced by stroke and traumatic brain injury through the systemic cholinergic anti-inflammatory pathway. In the present study, we focused on the nAChRs expressed on BECs rather than those widely expressed in the central nervous system and peripheral tissues, and examined whether activation of the nAChRs on BECs facilitates BBB function. We used primary cultures of rat brain endothelial cells to evaluate brain endothelial permeability and tight junction (TJ)-related protein expression after a 24-h exposure to PHA543613 (a selective α7 nAChR agonist) or 5-iodo-A-85380 (a selective α4ß2 nAChR agonist). We found that PHA543613 decreased sodium fluorescein permeability and increased the expression levels of claudin-5 and occludin, key TJ components. In contrast, 5-iodo-A-85380 had no effect on brain endothelial permeability or TJ protein expression. These findings suggest that the selective activation of α7 nAChRs on BECs has a specific role in upregulating BBB properties through increased claudin-5 and occludin expression.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Claudina-5/metabolismo , Células Endoteliales/metabolismo , Ocludina/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/metabolismo , Animales , Compuestos Bicíclicos Heterocíclicos con Puentes/administración & dosificación , Permeabilidad de la Membrana Celular , Agonistas Nicotínicos/administración & dosificación , Cultivo Primario de Células , Quinuclidinas/administración & dosificación , Ratas Wistar , Receptores Nicotínicos/metabolismo , Proteínas de Uniones Estrechas/metabolismo , Receptor Nicotínico de Acetilcolina alfa 7/agonistas
12.
J Cell Biochem ; 119(11): 9055-9063, 2018 11.
Artículo en Inglés | MEDLINE | ID: mdl-30076740

RESUMEN

Oncostatin M (OSM) is a member of the interleukin (IL)-6 family cytokines. We previously demonstrated that OSM induces blood-brain barrier (BBB) impairment. However, functional characterization of IL-6 family cytokines in BBB regulation and the cytokine-related intracellular signaling pathway remain unclear. In this study, we demonstrate that among IL-6 family cytokines, including IL-6 and leukemia inhibitory factor (LIF), OSM is the most potent molecule for inducing BBB dysfunction via prolonged activation of signal transducer and activator of transcription (STAT) 3 following Janus-activated kinase (JAK) activation. OSM but not IL-6 and LIF (100 ng/mL for 24 hours) markedly produced increased sodium fluorescein permeability and decreased transendothelial electrical resistance in rat brain endothelial cell (RBEC) monolayers. This OSM-induced BBB dysfunction was accompanied by decreased levels of claudin-5 expression in RBECs, which were ameliorated by JAK inhibitor. We examined the time-course of STAT3 phosphorylation in RBECs treated with OSM, IL-6, and LIF. OSM upregulated STAT3 phosphorylation levels during a 24 hours period with a peak at 10 minutes. While IL-6 and LIF transiently increased phosphorylated STAT3 at 10 minutes after addition, this phosphorylation decreased during the period from 1 to 24 hours after addition. These findings suggest that OSM-induced sustained increases in STAT3 phosphorylation levels largely contribute to BBB impairment. Thus, elevated OSM levels and activation of brain endothelial JAK/STAT3 signaling pathway under pathological conditions should be considered as a possible hallmark for induction and development of BBB impairment.


Asunto(s)
Barrera Hematoencefálica/efectos de los fármacos , Barrera Hematoencefálica/metabolismo , Oncostatina M/farmacología , Factor de Transcripción STAT3/metabolismo , Animales , Células Cultivadas , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Interleucina-6/farmacología , Factor Inhibidor de Leucemia/farmacología , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Transducción de Señal/efectos de los fármacos
13.
Brain Res ; 1692: 34-44, 2018 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-29702085

RESUMEN

Interleukin (IL)-6 is an important mediator of neurovascular dysfunction, neurodegeneration and/or neuroinflammation. We previously reported that brain pericytes released higher levels of IL-6 than did glial cells (astrocytes and microglia) in response to tumor necrosis factor (TNF)-α. Moreover, pericytes stimulated with TNF-α enhanced activation of BV-2 microglia. In this study, we investigated the mechanisms of TNF-α mediated induction of IL-6 release from brain pericytes and astrocytes and whether pericyte-derived IL-6 would facilitate activation of BV-2 microglia. Using rat brain pericyte and astrocyte primary cultures and pharmacological inhibitors, we found that, TNF-α induced the highest levels of IL-6 release from pericytes by activating the inhibitor kappa B (IκB)-nuclear factor kappa-light-chain-enhancer of activated B cells (NFκB) and Janus family of tyrosine kinase (JAK)-signal transducer and activator of transcription (STAT)3 pathways. STAT3 contributed to TNF-α induced nuclear translocation of phospho-NFκB in pericytes. TNF-α-induced IL-6 release in astrocytes was mediated by NFκB but not by STAT3. The presence of pericytes amplified TNF-α-induced iNOS mRNA expression in BV-2 microglia. This effect was blocked by a neutralizing antibody for IL-6. These findings indicated that crosstalk between the IκB-NFκB and JAK-STAT3 pathways is a pericyte specific mechanism, not occurring in astrocytes, for TNF-α-induced IL-6 release. IL-6 derived from pericytes enhanced microglial activation. Our findings increase understanding of the role of pericyte-microglia crosstalk in the brain under neuroinflammatory conditions and suggest a potentially attractive therapeutic target for brain inflammation.


Asunto(s)
Encéfalo/citología , Interleucina-6/metabolismo , Microglía/efectos de los fármacos , Pericitos/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Factor de Necrosis Tumoral alfa/farmacología , Animales , Células Cultivadas , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Proteínas I-kappa B/metabolismo , Ratones , FN-kappa B , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Factor de Transcripción STAT3/metabolismo
14.
PLoS One ; 12(5): e0177447, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28489922

RESUMEN

Diabetic complications are characterized by the dysfunction of pericytes located around microvascular endothelial cells. The blood-brain barrier (BBB) exhibits hyperpermeability with progression of diabetes. Therefore, brain pericytes at the BBB may be involved in diabetic complications of the central nervous system (CNS). We hypothesized that brain pericytes respond to increased brain thrombin levels in diabetes, leading to BBB dysfunction and diabetic CNS complications. Mice were fed a high-fat diet (HFD) for 2 or 8 weeks to induce obesity. Transport of i.v.-administered sodium fluorescein and 125I-thrombin across the BBB were measured. We evaluated brain endothelial permeability and expression of tight junction proteins in the presence of thrombin-treated brain pericytes using a BBB model of co-cultured rat brain endothelial cells and pericytes. Mice fed a HFD for 8 weeks showed both increased weight gain and impaired glucose tolerance. In parallel, the brain influx rate of sodium fluorescein was significantly greater than that in mice fed a normal diet. HFD feeding inhibited the decline in brain thrombin levels occurring during 6 weeks of feeding. In the HFD fed mice, plasma thrombin levels were significantly increased, by up to 22%. 125I-thrombin was transported across the BBB in normal mice after i.v. injection, with uptake further enhanced by co-injection of unlabeled thrombin. Thrombin-treated brain pericytes increased brain endothelial permeability and caused decreased expression of zona occludens-1 (ZO-1) and occludin and morphological disorganization of ZO-1. Thrombin also increased mRNA expression of interleukin-1ß and 6 and tumor necrosis factor-α in brain pericytes. Thrombin can be transported from circulating blood through the BBB, maintaining constant levels in the brain, where it can stimulate pericytes to induce BBB dysfunction. Thus, the brain pericyte-thrombin interaction may play a key role in causing BBB dysfunction in obesity-associated diabetes and represent a therapeutic target for its CNS complications.


Asunto(s)
Barrera Hematoencefálica/patología , Complicaciones de la Diabetes/complicaciones , Obesidad/complicaciones , Pericitos/patología , Trombina/metabolismo , Animales , Barrera Hematoencefálica/metabolismo , Células Cultivadas , Complicaciones de la Diabetes/metabolismo , Complicaciones de la Diabetes/patología , Masculino , Ratones , Ratones Endogámicos ICR , Obesidad/metabolismo , Obesidad/patología , Pericitos/metabolismo , Ratas Wistar , Proteína de la Zonula Occludens-1/metabolismo
15.
Neuroscience ; 350: 146-157, 2017 05 14.
Artículo en Inglés | MEDLINE | ID: mdl-28344073

RESUMEN

Thrombin, an essential component in the coagulation cascade, participates in the pathogenesis of brain diseases, such as ischemic stroke, intracerebral hemorrhage, Alzheimer's disease and Parkinson's disease through blood-brain barrier (BBB) dysfunction. It is thought that the thrombin-matrix metalloproteinase (MMP)-9 axis is an important process in the pathogenesis of neurovascular disease, such as BBB dysfunction. We recently reported that brain pericytes are the most MMP-9-releasing cells in response to thrombin stimulation among the BBB-constituting cells. This thrombin-induced MMP-9 release is partially due to protease-activated receptor (PAR1), one of the specific thrombin receptors. Then, we evaluated the intracellular signaling pathways involved in MMP-9 release and the contribution of thrombin-reactive brain pericytes to BBB dysfunction. PKC activator evoked MMP-9 release from brain pericytes. The thrombin-induced MMP-9 release was inhibited by U0126, LY294002, Go6976, and Go6983. However, Go6976 decreased phosphorylation levels of PKCθ and Akt, and Go6983 decreased phosphorylation levels of PKCδ and extracellular signal-regulated kinase (ERK). Additionally, treatment of pericytes with thrombin or PAR1-activating peptide stimulated PKCδ/θ signaling. These substances impaired brain endothelial barrier function in the presence of brain pericytes. Brain pericytes function through two independent downstream signaling pathways via PAR1 activation to release MMP-9 in response to thrombin - the PKCθ-Akt pathway and the PKCδ-ERK1/2 pathway. These pathways participate in PAR1-mediated MMP-9 release from pericytes, which leads to BBB dysfunction. Brain pericytes and their specific signaling pathways could provide novel therapeutic targets for thrombin-induced neurovascular diseases.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Pericitos/metabolismo , Proteína Quinasa C-delta/metabolismo , Proteína Quinasa C-theta/metabolismo , Receptor PAR-1/metabolismo , Trombina/metabolismo , Animales , Encéfalo/metabolismo , Células Cultivadas , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Ratas , Receptores de Trombina/metabolismo
16.
J Pharmacol Sci ; 129(1): 78-81, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26382104

RESUMEN

Chronic obstructive pulmonary disease (COPD) shows progressive, irreversible airflow limitation induced by emphysema and lung inflammation. The aim of the present study was to determine if COPD conditions induce blood-brain barrier (BBB) dysfunction. We found that the intratracheal administration of porcine pancreatic elastase (PPE; 3 U) induced alveolar enlargement, increased neutrophil number in bronchoalveolar lavage fluid, and decreased blood oxygen saturation in mice at 21 days after inhalation. In parallel with these lung damages, BBB permeability to sodium fluorescein and Evans blue albumin was markedly increased. Our findings demonstrate that COPD conditions are associated with risk for BBB impairment.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Barrera Hematoencefálica/fisiopatología , Elastasa Pancreática/efectos adversos , Enfermedad Pulmonar Obstructiva Crónica/inducido químicamente , Enfermedad Pulmonar Obstructiva Crónica/metabolismo , Enfermedad Pulmonar Obstructiva Crónica/fisiopatología , Administración por Inhalación , Animales , Líquido del Lavado Bronquioalveolar/citología , Modelos Animales de Enfermedad , Azul de Evans/metabolismo , Fluoresceína/metabolismo , Recuento de Leucocitos , Ratones , Neutrófilos , Oxígeno/sangre , Elastasa Pancreática/administración & dosificación , Permeabilidad , Porcinos
18.
Neurosci Lett ; 599: 109-14, 2015 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-26002077

RESUMEN

In the acute phase of intracerebral hemorrhage (ICH), hemorrhagic transformation and brain edema are associated with blood-brain barrier (BBB) disruption. Elevated levels of thrombin, a coagulation factor, contribute to the development of brain edema during ICH through matrix metalloproteinase (MMP)-9 production. Thrombin directly induces a variety of cellular responses through its specific receptors known as protease-activated receptors (PARs). However, it remains unclear which cell types constituting the BBB mainly produce MMP-9 in response to thrombin. Here, we compared the MMP-9 release induced by thrombin using primary cultures of rat brain microvascular endothelial cells, astrocytes, and pericytes. Brain pericytes exhibited the highest levels of MMP-9 release due to thrombin stimulation among the BBB cells. The pattern of PAR mRNA expression in pericytes was characterized by high expression of PAR1 and moderate expression of PAR4. Heat-inactivated thrombin failed to stimulate pericytes to release MMP-9. A selective PAR1 inhibitor SCH79797 blocked the thrombin-induced MMP-9 release from pericytes. These findings suggest that both PAR1 and PAR4 mediate thrombin-induced MMP-9 release from pericytes. The present study raises the possibility that brain pericytes could play a pivotal role as a highly thrombin-sensitive and MMP-9-producing cell type at the BBB in brain damage including ICH.


Asunto(s)
Barrera Hematoencefálica/citología , Metaloproteinasa 9 de la Matriz/metabolismo , Pericitos/citología , Trombina/metabolismo , Animales , Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Barrera Hematoencefálica/metabolismo , Encéfalo/irrigación sanguínea , Encéfalo/citología , Células Endoteliales/efectos de los fármacos , Células Endoteliales/metabolismo , Microvasos/citología , Microvasos/metabolismo , Pericitos/efectos de los fármacos , Pericitos/metabolismo , Ratas Wistar , Receptores Proteinasa-Activados/metabolismo , Trombina/farmacología
19.
Biochem Biophys Res Commun ; 457(4): 532-7, 2015 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-25597994

RESUMEN

Insulin signaling in the hypothalamus plays an important role in food intake and glucose homeostasis. Hypothalamic neuronal functions are modulated by glial cells; these form an extensive network connecting the neurons and cerebral vasculature, known as the neurovascular unit (NVU). Brain pericytes are periendothelial accessory structures of the blood-brain barrier and integral members of the NVU. However, the interaction between pericytes and neurons is largely unexplored. Here, we investigate whether brain pericytes could affect hypothalamic neuronal insulin signaling. Our immunohistochemical observations demonstrated the existence of pericytes in the mouse hypothalamus, exhibiting immunoreactivity of platelet-derived growth factor receptor ß (a pericyte marker), and laminin, a basal lamina marker. We then exposed a murine hypothalamic neuronal cell line, GT1-7, to conditioned medium obtained from primary cultures of rat brain pericytes. Pericyte-conditioned medium (PCM), but not astrocyte- or aortic smooth muscle cell-conditioned medium, increased the insulin-stimulated phosphorylation of Akt in GT1-7 cells in a concentration-dependent manner. PCM also enhanced insulin-stimulated tyrosine phosphorylation of insulin receptor ß without changing its expression or localization in cytosolic or plasma membrane fractions. These results suggest that pericytes, rather than astrocytes, increase insulin sensitivity in hypothalamic neurons by releasing soluble factors under physiological conditions in the NVU.


Asunto(s)
Medios de Cultivo Condicionados/metabolismo , Hipotálamo/citología , Resistencia a la Insulina , Insulina/metabolismo , Pericitos/metabolismo , Animales , Línea Celular , Células Cultivadas , Hipotálamo/irrigación sanguínea , Ratones , Pericitos/citología , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas , Ratas Wistar , Receptor de Insulina/metabolismo , Receptor beta de Factor de Crecimiento Derivado de Plaquetas/metabolismo , Transducción de Señal
20.
Neurosci Lett ; 578: 133-8, 2014 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-24993300

RESUMEN

Brain pericytes are involved in neurovascular dysfunction, neurodegeneration and/or neuroinflammation. In the present study, we focused on the proinflammatory properties of brain pericytes to understand their participation in the induction of inflammation at the neurovascular unit (NVU). The NVU comprises different cell types, namely, brain microvascular endothelial cells, pericytes, astrocytes and microglia. Among these, we found pericytes to be the most sensitive to tumor necrosis factor (TNF)-α, possessing a unique cytokine and chemokine release profile. This was characterized by marked release of interleukin (IL)-6 and macrophage inflammatory protein-1α. Furthermore, TNF-α-stimulated pericytes induced expression of inducible nitric oxide synthase and IL-1ß mRNAs, as an index of BV-2 microglial cell activation state, to the highest levels. Based on these findings, the possibility that brain pericytes act specifically as TNF-α-sensitive cells and as effectors of TNF-α through the release of proinflammatory factors, and that, as such, they have a role in inducing brain inflammation, should be considered.


Asunto(s)
Barrera Hematoencefálica/metabolismo , Quimiocinas/metabolismo , Citocinas/metabolismo , Encefalitis/metabolismo , Microglía/metabolismo , Pericitos/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Astrocitos/metabolismo , Células Endoteliales/metabolismo , Interleucina-1beta/metabolismo , Óxido Nítrico Sintasa/metabolismo , Pericitos/efectos de los fármacos , Cultivo Primario de Células , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Factor de Necrosis Tumoral alfa/farmacología
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