PTBP1 Depletion in Mature Astrocytes Reveals Distinct Splicing Alterations Without Neuronal Features

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• Astrocyte-to-neuron reprogramming via PTBP1 depletion is a proposed therapeutic strategy.
• Efficacy is debated due to inconsistent results and questions about PTBP1 inactivation completeness.

Purpose of the Study:

• To investigate the effect of PTBP1 loss of function in mature astrocytes on RNA splicing.
• To determine if PTBP1 knockout in astrocytes leads to neuronal reprogramming using lineage tracing.

Main Methods:

• Genetic ablation of PTBP1 in adult Aldh1l1-Cre/ERT2 Ai14 mice.
• Lineage tracing to track astrocyte-derived cells.
• RNA splicing analysis and transcriptomic profiling.

Main Results:

• No widespread neuronal induction observed despite PTBP1 knockout.
• A small fraction of cells showed neuron-like transcriptomic signatures.
• PTBP1 loss induced splicing alterations distinct from neuronal patterns, affecting an astrocytic splicing program.

Conclusions:

• PTBP1 depletion alone is ineffective for astrocyte-to-neuron reprogramming.
• Combining splicing and lineage analyses is crucial for mechanistic understanding.
• Loss of astrocytic PTBP1 impacts a distinct splicing program, not neuronal differentiation.