Blood Flow Promotes Neuronal Migration in the Adult Brain

Core Concepts

Blood flow facilitates the migration of new neurons in the adult brain by promoting somal translocation through ghrelin signaling.

Abstract

The study investigates the role of blood flow in the migration of new neurons in the adult brain. Key findings:

New neurons migrate along blood vessels throughout their migration route in the olfactory bulb (OB) and rostral migratory stream (RMS).
Neuronal migration is faster near blood vessels with high blood flow compared to those with low flow.
Inhibition of blood flow attenuates neuronal migration, suggesting blood contains factors that promote migration.
The blood-derived hormone ghrelin directly promotes neuronal migration by activating actin cytoskeleton contraction at the rear of the cell soma, leading to enhanced somal translocation.
Ghrelin signaling through its receptor GHSR1a is required for the pro-migratory effects of ghrelin on new neurons.
Calorie restriction, which increases blood ghrelin levels, promotes neuronal migration and maturation in the OB, an effect mediated by ghrelin signaling.

The results indicate that blood flow facilitates neuronal migration in the adult brain through blood-derived ghrelin signaling, which could be a mechanism to improve olfactory function for food-seeking behavior during starvation.

Stats

New neurons migrate faster near high-flow blood vessels compared to low-flow vessels.
Inhibition of blood flow by bilateral carotid artery stenosis or photothrombotic clot formation reduces neuronal migration speed.
Ghrelin application increases the migratory phase proportion and somal translocation speed of cultured new neurons.
Calorie restriction increases the proportion of new neurons in the glomerular layer of the olfactory bulb.

Quotes

"Blood flow promotes the migration of new olfactory-bulb neurons in the adult brain."
"Ghrelin signaling promotes somal translocation by activating actin cytoskeleton contraction at the rear of the cell soma."
"Calorie restriction facilitates the OB neurogenesis through ghrelin signaling."

Key Insights Distilled From

Neuronal migration depends on blood flow in the adult brain

by Ogino,T., Sa... at www.biorxiv.org 05-18-2024

https://www.biorxiv.org/content/10.1101/2024.05.16.594485v1

Deeper Inquiries

How might the blood flow-dependent neuronal migration mechanism be leveraged for therapeutic applications, such as promoting neurogenesis after brain injury or neurodegenerative diseases?

The blood flow-dependent neuronal migration mechanism uncovered in this study presents exciting possibilities for therapeutic applications in promoting neurogenesis after brain injury or in neurodegenerative diseases. By understanding how blood flow influences neuronal migration, researchers can potentially develop strategies to enhance this process in damaged or degenerating brain regions. One approach could involve modulating blood flow to specific brain areas to facilitate the migration of new neurons to the sites of injury or degeneration. This could be achieved through pharmacological interventions or even non-invasive techniques such as transcranial magnetic stimulation, which has been shown to influence blood flow in the brain.
Furthermore, the identification of blood-derived factors that promote neuronal migration, such as ghrelin, opens up avenues for the development of targeted therapies. By manipulating the levels of these factors in the bloodstream, either through pharmacological means or dietary interventions, it may be possible to enhance neurogenesis and neuronal migration in the adult brain. This could be particularly beneficial in conditions where neurogenesis is impaired, such as in neurodegenerative diseases like Alzheimer's or Parkinson's.
Overall, leveraging the blood flow-dependent neuronal migration mechanism for therapeutic applications holds promise for enhancing brain repair and regeneration in various neurological conditions.

What other blood-derived factors, in addition to ghrelin, might influence neuronal migration and maturation in the adult brain?

In addition to ghrelin, several other blood-derived factors may influence neuronal migration and maturation in the adult brain. One such factor is brain-derived neurotrophic factor (BDNF), which is known to play a crucial role in neurogenesis, neuronal survival, and synaptic plasticity. BDNF has been shown to promote the migration of new neurons in the adult brain and enhance their maturation into functional neurons.
Another important factor is vascular endothelial growth factor (VEGF), which is involved in angiogenesis and neuroprotection. VEGF has been shown to enhance neurogenesis and promote the migration of new neurons along blood vessels in the brain. Its role in regulating blood vessel formation and maintenance can indirectly influence neuronal migration by providing a supportive environment for new neuron migration.
Furthermore, insulin-like growth factor 1 (IGF-1) is another blood-derived factor that can influence neuronal migration and maturation. IGF-1 has been shown to enhance neurogenesis and promote the survival and differentiation of new neurons in the adult brain. Its effects on neuronal migration may be mediated through its role in cell growth and differentiation processes.
These are just a few examples of blood-derived factors that can influence neuronal migration and maturation in the adult brain. The complex interplay between these factors and their effects on neurogenesis highlight the intricate regulatory mechanisms involved in brain development and repair.

Could the insights from this study on the relationship between blood flow, ghrelin signaling, and neuronal migration provide clues about the evolutionary origins of the olfactory system and its role in foraging behavior?

The insights gained from the study on the relationship between blood flow, ghrelin signaling, and neuronal migration could indeed provide valuable clues about the evolutionary origins of the olfactory system and its role in foraging behavior. The findings suggest that blood flow plays a crucial role in promoting neuronal migration in the adult brain, particularly in regions associated with olfactory function such as the olfactory bulb.
From an evolutionary perspective, the olfactory system is one of the oldest sensory systems in vertebrates and is essential for survival-related behaviors such as foraging and predator avoidance. The migration of new neurons to the olfactory bulb, facilitated by blood flow and ghrelin signaling, may have evolutionary significance in enhancing the olfactory function for food-seeking behavior during starvation or other challenging conditions.
The link between blood flow, ghrelin signaling, and neuronal migration in the olfactory system could shed light on how these mechanisms have evolved to optimize sensory function in response to environmental cues. By understanding the molecular and cellular processes that underlie these interactions, researchers may uncover evolutionary adaptations that have shaped the olfactory system and its role in guiding behaviors essential for survival and reproduction.