spinal-cord-transection-in-xenopus-laevis-tadpoles

Spinal Cord Transection In <em>Xenopus laevis</em> Tadpoles

Spinal cord injury (SCI) is a permanent affliction, which affects the central nervous system (CNS) motor and sensory nerves, resulting in paralysis ...

P. Universidad Católica de Chile

The Wnt signaling pathway plays important roles during different stages of neuronal development, including neuronal polarization and dendritic and axonal outgrowth. However, little is known about the identity of the Frizzled receptors mediating these processes. In the present study, we investigated the role of Frizzled-5 (Fzd5) on neuronal development in cultured Sprague-Dawley rat hippocampal neurons. We found that Fzd5 is expressed early in cultured neurons on actin-rich structures localized at minor neurites and axonal growth cones. At 4 DIV, Fzd5 polarizes towards the axon, where its expression is detected mainly at the peripheral zone of axonal growth cones, with no obvious staining at dendrites; suggesting a role of Fzd5 in neuronal polarization. Overexpression of Fzd5 during the acquisition of neuronal polarity induces mislocalization of the receptor and a loss of polarized axonal markers. Fzd5 knock-down leads to loss of axonal proteins, suggesting an impaired neuronal polarity. In contrast, overexpression of Fzd5 in neurons that are already polarized did not alter polarity, but decreased the total length of axons and increased total dendrite length and arborization. Fzd5 activated JNK in HEK293 cells and the effects triggered by Fzd5 overexpression in neurons were partially prevented by inhibition of JNK, suggesting that a non-canonical Wnt signaling mechanism might be involved. Our results suggest that, Fzd5 has a role in the establishment of neuronal polarity, and in the morphogenesis of neuronal processes, in part through the activation of the non-canonical Wnt mechanism involving JNK. 

Frizzled-5 receptor is involved in neuronal polarity and morphogenesis of hippocampal neurons.

 has been widely used as a model organism to study wound healing and regeneration. During early development and at tadpole stages,  is a quick healer and is able to regenerate multiple complex organs-abilities that decrease with the progression of metamorphosis. This unique capacity leads us to question which mechanisms allow and direct regeneration at stages before the beginning of metamorphosis and which ones are responsible for the loss of regenerative capacities during later stages.  is an ideal model to study regeneration and has contributed to the understanding of morphological, cellular, and molecular mechanisms involved in these processes. Nevertheless, there is still much to learn. Here we provide an overview on using  as a model organism to study regeneration and introduce protocols that can be used for studying wound healing and regeneration at multiple levels, thus enhancing our understanding of these phenomena.

Article	Year
Frizzled-5 receptor is involved in neuronal polarity and morphogenesis of hippocampal neurons. PloS one\| PubMed ID: 24205342	2013
, a Model to Study Wound Healing and Regeneration: Experimental Approaches. Cold Spring Harbor protocols\| PubMed ID: 33782095	2021

Paula G. Slater

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