Spatial distribution of insulin-like growth factor binding protein-2 following hypoxic-ischemic injury
Spatial distribution of insulin-like growth factor binding protein-2 following hypoxic-ischemic injury
Abstract Background Insulin-like growth factor binding protein-2 (IGFBP-2) regulates the bioavailability, transportation, and localization of insulin-like growth factor-I (IGF-I), an effective neuroprotectant in animal stroke models especially when administered intranasally. Therefore, determining IGFBP-2′s endogenous distribution in the normal and ischemic brain is essential in maximizing the neuroprotective potential of the intranasal IGF-I treatment approach. However, current data on IGFBP-2 is limited to mRNA and in situ hybridization studies. The purpose of this study was to determine if there are any changes in IGFBP-2 protein levels and distribution in ischemic brain and also to determine if IGFBPs play a role in the transportation of intranasally administered IGF-I into the brain. Results Using an in vitro approach, we show that ischemia causes changes in the distribution of IGFBP-2 in primary cortical neurons and astrocytes. In addition, we show using the transient middle cerebral artery occlusion (MCAO) model in mice that there is a significant increase in IGFBP-2 levels in the stroke penumbra and core after 72 h. This correlated with an overall increase in IGF-I after stroke, with the highest levels of IGF-I in the stroke core after 72 h. Brain sections from stroke mice indicate that neurons and astrocytes located in the penumbra both have increased expression of IGFBP-2, however, IGFBP-2 was not detected in microglia. We used binding competition studies to show that intranasally administered exogenous IGF-I uptake into the brain is not receptor mediated and is likely facilitated by IGFBPs. Conclusions The change in protein levels indicates that IGFBP-2 plays an IGF-I-dependent and -independent role in the brain’s acute (neuroprotection) and chronic (tissue remodeling) response to hypoxic-ischemic injury. Competition studies indicate that IGFBPs may have a role in rapid transportation of exogenous IGF-I from the nasal tissue to the site of injury.
Cerebral Cortex, Male, Neurons, Primary Cell Culture, Biological Transport, Olfactory Bulb, Rats, Cellular and Molecular Neuroscience, Insulin-Like Growth Factor Binding Protein 2, Mice, Astrocytes, Cerebellum, Hypoxia-Ischemia, Brain, Animals, Microglia, Insulin-Like Growth Factor I, Administration, Intranasal, Research Article
Cerebral Cortex, Male, Neurons, Primary Cell Culture, Biological Transport, Olfactory Bulb, Rats, Cellular and Molecular Neuroscience, Insulin-Like Growth Factor Binding Protein 2, Mice, Astrocytes, Cerebellum, Hypoxia-Ischemia, Brain, Animals, Microglia, Insulin-Like Growth Factor I, Administration, Intranasal, Research Article
3 Research products, page 1 of 1
- 2017IsRelatedTo
- 2017IsRelatedTo
- 2017IsRelatedTo
citations This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).21 popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.Top 10% influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).Average impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.Average
