Dual Specificity Phosphatases Support Axon Plasticity and Viability

Area of Science:

• Neuroscience
• Molecular Biology
• Cell Biology

Background:

• Axonal degeneration (AxD) significantly hinders recovery in peripheral neuropathies.
• Dual specificity phosphatases (DUSPs), also known as MAP kinase phosphatases (MKPs), play a role in cellular processes.

Purpose of the Study:

• To investigate the role of DUSPs in supporting autonomous axon plasticity and viability.
• To determine the impact of DUSP knockdown on neuronal function and survival.

Main Methods:

• Studied DUSP 1 and 4 expression in sensory neurons.
• Utilized knockdown techniques for DUSP 1 and 4 in adult dissociated sensory neurons.
• Assessed neurite outgrowth and sensitivity to axonopathy induced by capsaicin via TrpV1 activation.
• Examined neurofilament dissolution in explanted nerves and axon excitability in vivo.
• Investigated the interaction with DLK and SARM1 pathways.

Main Results:

• DUSP 1 and 4 were found in sensory neurons.
• Knockdown of DUSP 1 or 4 impaired neurite outgrowth and sensitized neurons to axonopathy.
• DUSP inhibition heightened neurofilament dissolution ex vivo.
• In vivo, DUSP knockdown led to rapid loss of motor axon excitability.
• SARM1 siRNA abrogated DUSP-mediated excitability loss, while DLK knockdown did not prevent axonopathy sensitivity.

Conclusions:

• DUSPs are essential for maintaining axon plasticity and survival.
• DUSP deficiency accelerates neurofilament breakdown and axon degeneration.
• Targeting DUSPs may offer therapeutic strategies for peripheral neuropathies.