miR-155-5p Promotes Dorsal Root Ganglion Neuron Axonal Growth in an Inhibitory Microenvironment via the cAMP/PKA Pathway

Int. J. Biol. Sci., 2019 · DOI: 10.7150/ijbs.31904 · Published: June 2, 2019

Simple Explanation

This study investigates how miR-155-5p, a small RNA molecule, affects the growth of nerve fibers (axons) from dorsal root ganglion (DRG) neurons, which are important for sensory function after spinal cord injury. The research shows that miR-155-5p can promote axon growth even in an environment that normally inhibits such growth, such as after a spinal cord injury. The mechanism involves the cAMP/PKA pathway, a signaling pathway important for nerve regeneration, and the molecule PKI-α, which miR-155-5p targets.

Study Duration

3 Months

Participants

204 adult female Wistar rats and 10 neonatal Wistar rats

Evidence Level

Not specified

Key Findings

1
miR-155-5p promotes DRG neuron axon growth via the cAMP/PKA pathway.
2
miR-155-5p enhances DRG neuron axon growth in an inhibitory microenvironment containing IL-1β, TNF-α, or MAG.
3
Upregulated miR-155-5p can repair SDCL by enhancing DRG neuron axon growth via the cAMP/PKA pathway.

Research Summary

This study aimed to determine the key miRNAs to regulate the promotion of spinal cord sensory function recovery by SNCI and clarify the associated pathway in vitro and in vivo to develop an alternative treatment strategy. The miRNA expression profile of SDCL and SNCI group rats were detected by microarray. We found that miR-155-5p was downregulated at all time points in both groups. miR-155-5p plays a pivotal role in controlling DRG neuron axon growth via the cAMP/PKA pathway, therefore improving sensory functional recovery post SDCL.

Practical Implications

Therapeutic Target

miR-155-5p could be a novel therapeutic target to promote sensory functional recovery post SDCL.

Drug Development

These findings can be used to develop drugs that target miR-155-5p to improve spinal cord injury outcomes.

Understanding Recovery

The study enhances the understanding of molecular mechanisms involved in spinal cord injury recovery.

Study Limitations

1
The study only focuses on one miRNA (miR-155-5p).
2
The study is limited to a rat model of spinal cord injury.
3
The study does not fully elucidate the downstream targets of the cAMP/PKA pathway.

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