Elevated nuclear TDP-43 induces constitutive exon skipping.

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Cytoplasmic inclusions and nuclear TDP-43 loss are hallmarks of neurodegenerative diseases.
• Gain- and loss-of-function mechanisms are implicated in TDP-43 proteinopathies.
• TDP-43 overexpression models are used to study gain-of-function disease mechanisms.

Purpose of the Study:

• To investigate TDP-43-mediated changes in RNA splicing.
• To explore species-specific splicing patterns in TDP-43 overexpression models.
• To correlate splicing alterations with neurodegenerative disease pathology.

Main Methods:

• Analyzed RNA-seq data from mouse and human neurons overexpressing TDP-43.
• Investigated the relationship between TDP-43 levels and exon repression in vitro.
• Examined human brain samples and public RNA datasets for splicing changes and disease correlation.

Main Results:

• Excessive nuclear TDP-43 induces constitutive, largely species-specific exon skipping.
• Aberrant exon skipping in human brains shows no correlation with disease.
• Cryptic exon incorporation, linked to TDP-43 loss, is a distinct disease-associated event.

Conclusions:

• Caution is needed when interpreting TDP-43 overexpression data.
• Controlling for TDP-43-induced exon skipping is crucial for accurate disease modeling.
• Findings differentiate effects of TDP-43 gain-of-function versus loss-of-function.