Role of Wnt Signaling in Adult Hippocampal Neurogenesis in Health and Disease

Newborn neurons in the adult hippocampus are regulated by many intrinsic and extrinsic cues. It is well accepted that elevated glucocorticoid levels lead to downregulation of adult neurogenesis, which this review discusses as one reason why psychiatric diseases, such as major depression, develop after long-term stress exposure. In reverse, adult neurogenesis has been suggested to protect against stress-induced major depression, and hence, could serve as a resilience mechanism. In this review, we will summarize current knowledge about the functional relation of adult neurogenesis and stress in health and disease. A special focus will lie on the mechanisms underlying the cascades of events from prolonged high glucocorticoid concentrations to reduced numbers of newborn neurons. In addition to neurotransmitter and neurotrophic factor dysregulation, these mechanisms include immunomodulatory pathways, as well as microbiota changes influencing the gut-brain axis. Finally, we discuss recent findings delineating the role of adult neurogenesis in stress resilience.

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Potential Role of Adult Hippocampal Neurogenesis in Traumatic Brain Injury

Current Medicinal Chemistry ◽

10.2174/0929867328666210923143713 ◽

2021 ◽

Vol 28 ◽

Author(s):

Lucas Alexandre Santos Marzano ◽

Fabyolla Lúcia Macedo de Castro ◽

Caroline Amaral Machado ◽

João Luís Vieira Monteiro de Barros ◽

Thiago Macedo e Cordeiro ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Clinical Studies ◽

Molecular Mechanisms ◽

Hippocampal Neurogenesis ◽

Cognitive Outcomes ◽

Adult Hippocampal Neurogenesis ◽

The Brain

: Traumatic brain injury (TBI) is a serious cause of disability and death among young and adult individuals, displaying complex pathophysiology including cellular and molecular mechanisms that are not fully elucidated. Many experimental and clinical studies investigated the potential relationship between TBI and the process by which neurons are formed in the brain, known as neurogenesis. Currently, there are no available treatments for TBI’s long-term consequences being the search for novel therapeutic targets, a goal of highest scientific and clinical priority. Some studies evaluated the benefits of treatments aimed at improving neurogenesis in TBI. In this scenario, herein, we reviewed current pre-clinical studies that evaluated different approaches to improving neurogenesis after TBI while achieving better cognitive outcomes, which may consist in interesting approaches for future treatments.

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Canonical Wnt-signaling modulates the tempo of dendritic growth of adult-born hippocampal neurons

10.1101/2020.01.14.905919 ◽

2020 ◽

Author(s):

Jana Heppt ◽

Marie-Theres Wittmann ◽

Jingzhong Zhang ◽

Daniela Vogt-Weisenhorn ◽

Nilima Prakash ◽

...

Keyword(s):

Young Adult ◽

Wnt Signaling ◽

Progenitor Cells ◽

Dendritic Growth ◽

Functional Integration ◽

Hippocampal Neurogenesis ◽

Adult Hippocampal Neurogenesis ◽

Canonical Wnt Signaling ◽

Adult Born Neurons ◽

Canonical Wnt

AbstractIn adult hippocampal neurogenesis neural stem/progenitor cells generate new dentate granule neurons that contribute to hippocampal plasticity. The establishment of a morphologically defined dendritic arbor is central to the functional integration of adult-born neurons. Here, we investigated the role of canonical Wnt/β-catenin-signaling in dendritogenesis of adult-born neurons. We show that canonical Wnt-signaling follows a biphasic pattern, with high activity in stem/progenitor cells, attenuation in early immature neurons, and re-activation during maturation, and demonstrate that the biphasic activity pattern is required for proper dendrite development. Increasing β-catenin-signaling in maturing neurons of young adult mice transiently accelerated dendritic growth, but eventually resulted in dendritic defects and excessive spine numbers. In middle-aged mice, in which protracted dendrite and spine development was paralleled by lower canonical Wnt-signaling activity, enhancement of β-catenin-signaling restored dendritic growth and spine formation to levels observed in young adult animals. Our data indicate that precise timing and strength of β-catenin-signaling is essential for the correct functional integration of adult-born neurons and suggest Wnt/β-catenin-signaling as a pathway to ameliorate deficits in adult neurogenesis during aging.

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