Limits...
Pericytes contribute to the disruption of the cerebral endothelial barrier via increasing VEGF expression: implications for stroke.

Bai Y, Zhu X, Chao J, Zhang Y, Qian C, Li P, Liu D, Han B, Zhao L, Zhang J, Buch S, Teng G, Hu G, Yao H - PLoS ONE (2015)

Bottom Line: Our findings demonstrated that treatment of human brain microvascular pericytes with sodium cyanide (NaCN) and glucose deprivation resulted in increased expression of vascular endothelial growth factor (VEGF) via the activation of tyrosine kinase Src, with downstream activation of mitogen activated protein kinase and PI3K/Akt pathways and subsequent translocation of NF-κB into the nucleus.Conditioned medium from NaCN-treated pericytes led to increased permeability of endothelial cells, and this effect was significantly inhibited by VEGF-neutralizing antibody.Understanding the regulation of VEGF expression could open new avenues for the development of potential therapeutic targets for stroke and other neurological disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Medical School of Southeast University, Nanjing, China.

ABSTRACT
Disruption of the blood-brain barrier (BBB) integrity occurring during the early onset of stroke is not only a consequence of, but also contributes to the further progression of stroke. Although it has been well documented that brain microvascular endothelial cells and astrocytes play a critical role in the maintenance of BBB integrity, pericytes, sandwiched between endothelial cells and astrocytes, remain poorly studied in the pathogenesis of stroke. Our findings demonstrated that treatment of human brain microvascular pericytes with sodium cyanide (NaCN) and glucose deprivation resulted in increased expression of vascular endothelial growth factor (VEGF) via the activation of tyrosine kinase Src, with downstream activation of mitogen activated protein kinase and PI3K/Akt pathways and subsequent translocation of NF-κB into the nucleus. Conditioned medium from NaCN-treated pericytes led to increased permeability of endothelial cells, and this effect was significantly inhibited by VEGF-neutralizing antibody. The in vivo relevance of these findings was further corroborated in the stroke model of mice wherein the mice, demonstrated disruption of the BBB integrity and concomitant increase in the expression of VEGF in the brain tissue as well as in the isolated microvessel. These findings thus suggest the role of pericyte-derived VEGF in modulating increased permeability of BBB during stroke. Understanding the regulation of VEGF expression could open new avenues for the development of potential therapeutic targets for stroke and other neurological disease.

No MeSH data available.


Related in: MedlinePlus

NaCN-mediated induction of VEGF involves Src kinase activation.(A) NaCN (2mM) induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (B) Exposure of pericytes to glucose deprivation induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (C) Inhibition of Src activity by Src inhibitor-PP2 (10μM) resulted in amelioration of NaCN-mediated induction of VEGF. All the data are presented as mean±SD of four individual experiments (n = 4). *p<0.05, **p<0.01 vs control group; #p<0.05 vs NaCN-treated group.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4401453&req=5

pone.0124362.g002: NaCN-mediated induction of VEGF involves Src kinase activation.(A) NaCN (2mM) induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (B) Exposure of pericytes to glucose deprivation induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (C) Inhibition of Src activity by Src inhibitor-PP2 (10μM) resulted in amelioration of NaCN-mediated induction of VEGF. All the data are presented as mean±SD of four individual experiments (n = 4). *p<0.05, **p<0.01 vs control group; #p<0.05 vs NaCN-treated group.

Mentions: Role of tyrosine kinase Src has been shown to be involved in expression of VEGF during focal cerebral ischemia reperfusion in rats [41]. Moreover, mounting evidence from other studies also demonstrates that activation of Src kinase plays a critical role in VEGF expression [42,43]. We thus wanted to examine whether Src activation also played a role in NaCN-mediated induction of VEGF. As shown in Fig 2A, treatment of primary human pericytes with NaCN resulted in increased phosphorylation of Src in a time-dependent manner, with the peak activation at 5mins and a gradual decrease thereafter. Consistent with the effect induced by NaCN, exposure of pericytes to glucose deprivation resulted in Src phosphorylation as shown in Fig 2B. To confirm the role of Src activation in NaCN mediated induction of VEGF, pericytes were pre-treated with the Src inhibitor-PP2 for 1hour followed by incubation with NaCN for 24 hours. As shown in Fig 2C, treatment of cells with the Src inhibitor PP2 significantly inhibited NaCN-induced production of VEGF.


Pericytes contribute to the disruption of the cerebral endothelial barrier via increasing VEGF expression: implications for stroke.

Bai Y, Zhu X, Chao J, Zhang Y, Qian C, Li P, Liu D, Han B, Zhao L, Zhang J, Buch S, Teng G, Hu G, Yao H - PLoS ONE (2015)

NaCN-mediated induction of VEGF involves Src kinase activation.(A) NaCN (2mM) induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (B) Exposure of pericytes to glucose deprivation induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (C) Inhibition of Src activity by Src inhibitor-PP2 (10μM) resulted in amelioration of NaCN-mediated induction of VEGF. All the data are presented as mean±SD of four individual experiments (n = 4). *p<0.05, **p<0.01 vs control group; #p<0.05 vs NaCN-treated group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4401453&req=5

pone.0124362.g002: NaCN-mediated induction of VEGF involves Src kinase activation.(A) NaCN (2mM) induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (B) Exposure of pericytes to glucose deprivation induced Src phosphorylation in a time-dependent manner in primary human pericytes. Representative immunoblots from four separate experiments are presented. (C) Inhibition of Src activity by Src inhibitor-PP2 (10μM) resulted in amelioration of NaCN-mediated induction of VEGF. All the data are presented as mean±SD of four individual experiments (n = 4). *p<0.05, **p<0.01 vs control group; #p<0.05 vs NaCN-treated group.
Mentions: Role of tyrosine kinase Src has been shown to be involved in expression of VEGF during focal cerebral ischemia reperfusion in rats [41]. Moreover, mounting evidence from other studies also demonstrates that activation of Src kinase plays a critical role in VEGF expression [42,43]. We thus wanted to examine whether Src activation also played a role in NaCN-mediated induction of VEGF. As shown in Fig 2A, treatment of primary human pericytes with NaCN resulted in increased phosphorylation of Src in a time-dependent manner, with the peak activation at 5mins and a gradual decrease thereafter. Consistent with the effect induced by NaCN, exposure of pericytes to glucose deprivation resulted in Src phosphorylation as shown in Fig 2B. To confirm the role of Src activation in NaCN mediated induction of VEGF, pericytes were pre-treated with the Src inhibitor-PP2 for 1hour followed by incubation with NaCN for 24 hours. As shown in Fig 2C, treatment of cells with the Src inhibitor PP2 significantly inhibited NaCN-induced production of VEGF.

Bottom Line: Our findings demonstrated that treatment of human brain microvascular pericytes with sodium cyanide (NaCN) and glucose deprivation resulted in increased expression of vascular endothelial growth factor (VEGF) via the activation of tyrosine kinase Src, with downstream activation of mitogen activated protein kinase and PI3K/Akt pathways and subsequent translocation of NF-κB into the nucleus.Conditioned medium from NaCN-treated pericytes led to increased permeability of endothelial cells, and this effect was significantly inhibited by VEGF-neutralizing antibody.Understanding the regulation of VEGF expression could open new avenues for the development of potential therapeutic targets for stroke and other neurological disease.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, Medical School of Southeast University, Nanjing, China.

ABSTRACT
Disruption of the blood-brain barrier (BBB) integrity occurring during the early onset of stroke is not only a consequence of, but also contributes to the further progression of stroke. Although it has been well documented that brain microvascular endothelial cells and astrocytes play a critical role in the maintenance of BBB integrity, pericytes, sandwiched between endothelial cells and astrocytes, remain poorly studied in the pathogenesis of stroke. Our findings demonstrated that treatment of human brain microvascular pericytes with sodium cyanide (NaCN) and glucose deprivation resulted in increased expression of vascular endothelial growth factor (VEGF) via the activation of tyrosine kinase Src, with downstream activation of mitogen activated protein kinase and PI3K/Akt pathways and subsequent translocation of NF-κB into the nucleus. Conditioned medium from NaCN-treated pericytes led to increased permeability of endothelial cells, and this effect was significantly inhibited by VEGF-neutralizing antibody. The in vivo relevance of these findings was further corroborated in the stroke model of mice wherein the mice, demonstrated disruption of the BBB integrity and concomitant increase in the expression of VEGF in the brain tissue as well as in the isolated microvessel. These findings thus suggest the role of pericyte-derived VEGF in modulating increased permeability of BBB during stroke. Understanding the regulation of VEGF expression could open new avenues for the development of potential therapeutic targets for stroke and other neurological disease.

No MeSH data available.


Related in: MedlinePlus