Guidance Molecules in Axon Pruning and Cell Death

Vanderhaeghen, Pierre; Cheng, Hwai-Jong

doi:10.1101/cshperspect.a001859

Cited by 111 publications

(101 citation statements)

References 132 publications

(174 reference statements)

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“…Regardless of how hyperoxia affects expansion of type I cells, it clearly exerts a positive effect on the alveolar epithelium because it inhibits angiogenesis represented by expression of PECAM (Figure 1 (48). Axon overproduction followed by neuronal pruning and death are necessary for proper development of the brain (49). Postlactation involution of the mammary gland involves extensive death of the secretory epithelium and remodeling of the fat pad (50).…”

Section: Discussionmentioning

confidence: 99%

Neonatal Hyperoxia Stimulates the Expansion of Alveolar Epithelial Type II Cells

Yee¹,

Buczynski

O’Reilly³

2014

Am J Respir Cell Mol Biol

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Supplemental oxygen used to treat infants born prematurely disrupts angiogenesis and is a risk factor for persistent pulmonary disease later in life. Although it is unclear how neonatal oxygen affects development of the respiratory epithelium, alveolar simplification and depletion of type II cells has been observed in adult mice exposed to hyperoxia between postnatal Days 0 and 4. Because hyperoxia inhibits cell proliferation, we hypothesized that it depleted the adult lung of type II cells by inhibiting their proliferation at birth. Newborn mice were exposed to room air (RA) or hyperoxia, and the oxygenexposed mice were recovered in RA. Hyperoxia stimulated mRNA expressed by type II (Sftpc, Abca3) and type I (T1a, Aquaporin 5) cells and inhibited Pecam expressed by endothelial cells. 5-Bromo-2'-deoxyuridine labeling and fate mapping with enhanced green fluorescence protein controlled statically by the Sftpc promoter or conditionally by the Scgb1a1 promoter revealed increased Sftpc and Abca3 mRNA seen on Day 4 reflected an increase in expansion of type II cells shortly after birth. When mice were returned to RA, this expanded population of type II cells was slowly depleted until few were detected by 8 weeks. These findings reveal that hyperoxia stimulates alveolar epithelial cell expansion when it disrupts angiogenesis. The loss of type II cells during recovery in RA may contribute to persistent pulmonary diseases such as those reported in children born preterm who were exposed to supplemental oxygen.

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Section: Discussionmentioning

confidence: 99%

Neonatal Hyperoxia Stimulates the Expansion of Alveolar Epithelial Type II Cells

Yee¹,

Buczynski

O’Reilly³

2014

Am J Respir Cell Mol Biol

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“…Branch pruning may involve cellular factors that are important for branch degeneration (Luo and O'Leary, 2005), and its regulation may employ the same molecules that are used for axon guidance (Vanderhaeghen and Cheng, 2010). For example, an early study of the SEMA3A receptor, plexin A3 (PLXNA3), suggests that pruning of specific hippocampal mossy fibers and of pyramidal branches requires this pathway (Bagri et al, 2003), as both pruning events are defective in the Plxna3 mouse knockout.…”

Section: Pruning Branchesmentioning

confidence: 99%

Developmental regulation of axon branching in the vertebrate nervous system

2011

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SummaryDuring nervous system development, axons generate branches to connect with multiple synaptic targets. As with axon growth and guidance, axon branching is tightly controlled in order to establish functional neural circuits, yet the mechanisms that regulate this important process are less well understood. Here, we review recent advances in the study of several common branching processes in the vertebrate nervous system. By focusing on each step in these processes we illustrate how different types of branching are regulated by extracellular cues and neural activity, and highlight some common principles that underlie the establishment of complex neural circuits in vertebrate development.

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“…Initially, all connection weights are set to their maximum value of 1, reflecting the overabundance of synaptic connections as a result of progressive growth in the early phases of human brain development [14]. During development, useless connections in the human brain are gradually eliminated in a process called synaptic pruning, leaving only well-used connections, resulting in a more precise and mature circuitry [15]. This is modelled by decreasing the synaptic strengths of connections from activated neurons to non-activated neurons (thus, useless connections) after each timestep as follows:…”

Section: B Synaptic Strengths Learning and Memorymentioning

confidence: 99%

A biologically inspired recurrent neural network for sound source recognition incorporating auditory attention

Boes

Oldoni

Coensel

et al. 2013

The 2013 International Joint Conference on Neural Networks (IJCNN)

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Abstract-In this paper, a human-mimicking model for sound source recognition is presented. It consists of an artificial neural network with three neuron layers (input, middle and output) that are connected by feedback connections between the output and middle layer, on top of feedforward connections from the input to middle and middle to output layers. Learning is accomplished by the model following the Hebb principle, dictating that "cells that fire together, wire together", with some important alterations, compared to standard Hebbian learning, in order to prevent the model from forgetting previously learned patterns, when learning new ones. In addition, short-term memory is introduced into the model in order to facilitate and guide learning of neuronal synapses (long-term memory). As auditory attention is an essential part of human auditory scene analysis (ASA), it is also indispensable in any computational model mimicking it, and it is shown that different auditory attention mechanism naturally emerge from the neuronal behaviour as implemented in the model described in this paper. The learning behavior of the model is further investigated in the context of an urban sonic environment, and the importance of shortterm memory in this process is demonstrated. Finally, the effectiveness of the model is evaluated by comparing model output on presented sound recordings to a human expert listeners evaluation of the same fragments.

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Guidance Molecules in Axon Pruning and Cell Death

Cited by 111 publications

References 132 publications

Neonatal Hyperoxia Stimulates the Expansion of Alveolar Epithelial Type II Cells

Neonatal Hyperoxia Stimulates the Expansion of Alveolar Epithelial Type II Cells

Developmental regulation of axon branching in the vertebrate nervous system

A biologically inspired recurrent neural network for sound source recognition incorporating auditory attention

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