Netrin-1 hyperexpression in mouse brain promotes angiogenesis and long-term neurological recovery after transient focal ischemia.

Abstract

BACKGROUND AND PURPOSE:

Netrin-1 (NT-1) stimulates endothelial cell proliferation and migration in vitro and promotes focal neovascularization in the adult brain in vivo. This in vivo study in mice investigated the effect of NT-1 hyperexpression on focal angiogenesis and long-term functional outcome after transient middle cerebral artery occlusion (tMCAO).

METHODS:

Adeno-associated viral vectors carrying either the NT-1 gene (AAV-NT-1) or GFP (AAV-GFP) were generated and injected into the brains of separate groups of 93 mice. Seven days later, tMCAO followed by 7-28 days of reperfusion were carried out. Histological outcomes and behavioral deficits were quantified 7-28 days after tMCAO. Small cerebral vessel network and angiogenesis were assessed 28 days after tMCAO, using synchrotron radiation microangiography and immunohistochemistry.

RESULTS:

Western blot and immunohistochemistry showed that on the day of tMCAO, NT-1 hyperexpression had been achieved in both normal and ischemic hemispheres. Immunofluorescence imaging showed that NT-1 expression was primarily in neurons and astrocytes. Ischemia-induced infarction in the NT-1 hyperexpression group was attenuated in comparison to saline or AAV-GFP-treated groups (P<0.01). Similarly, neurological deficits were greatly improved in AAV-NT-1-treated mice compared with mice in saline or AAV-GFP-treated groups (P<0.05). In addition, angiogenesis was increased in AAV-NT-1-treated mice compared with the other 2 groups (P<0.05). In vivo synchrotron radiation microangiography 28 days after tMCAO revealed more branches in AAV-NT-1-treated mice than in other groups.

CONCLUSIONS:

AAV-NT-1 induced NT-1 hyperexpression before tMCAO reduced infarct size, enhanced neovascularization, and improved long-term functional recovery.

• Authors: Haiyan Lu, Yongting Wang, Xiaosong He, Falei Yuan, Xiaojie Lin, Bohua Xie, Guanghui Tang, Jun Huang, Yaohui Tang, Kunlin Jin, Shengdi Chen, Guo-Yuan Yang
• Journal: Stroke (Stroke) Vol. 43 Issue 3 Pg. 838-43 (Mar 2012) ISSN: 1524-4628 [Electronic] United States
• PMID: 22223243 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Nerve Growth Factors
• Ntn1 protein, mouse
• Tumor Suppressor Proteins
• Netrin-1

Topics

• Animals
• Behavior, Animal (drug effects)
• Blotting, Western
• Brain Chemistry (genetics, physiology)
• Capillaries (pathology)
• Cell Death (physiology)
• Cerebral Angiography (methods)
• Dependovirus (genetics)
• Fluorescent Antibody Technique
• Genetic Therapy (methods)
• Genetic Vectors
• Immunohistochemistry
• Infarction, Middle Cerebral Artery (pathology)
• Ischemic Attack, Transient (pathology, therapy)
• Male
• Mice
• Microscopy, Fluorescence
• Neovascularization, Physiologic (genetics, physiology)
• Nerve Growth Factors (biosynthesis, genetics, physiology)
• Netrin-1
• Neurons (pathology)
• Postural Balance (physiology)
• Recovery of Function
• Tumor Suppressor Proteins (biosynthesis, genetics, physiology)