U6 snRNA expression prevents toxicity in TDP-43-knockdown cells

Area of Science:

• Neuroscience
• Molecular Biology
• Genetics

Background:

• The transactivation response (TAR) RNA/DNA-binding protein 43 kDa (TDP-43) is linked to amyotrophic lateral sclerosis (ALS).
• TDP-43 depletion affects RNA splicing and can cause neuronal cell death.
• The impact of TDP-43 depletion on small nuclear RNA (snRNA) expression and its connection to cell death is not fully understood.

Purpose of the Study:

• To investigate the relationship between TDP-43 depletion, snRNA expression alterations, and neuronal cell death.
• To determine if U6 snRNA downregulation is a cause or consequence of TDP-43 depletion-induced cell death.

Main Methods:

• TDP-43 was knocked down in murine neuroblastoma Neuro2A cells.
• snRNA levels (U1, U2, U4, U6) were quantified over time.
• Cell death was assessed following TDP-43 knockdown.
• U6 snRNA was exogenously expressed to observe its effect on cell death and splicing.

Main Results:

• A time lag was observed between TDP-43 depletion and cell death.
• U6 snRNA levels significantly decreased before significant cell death occurred.
• Downregulation of U6 snRNA induced cell death.
• Exogenous U6 snRNA expression counteracted TDP-43 knockdown-induced cell death and partially rescued mis-splicing of specific transcripts.

Conclusions:

• TDP-43 regulates U6 snRNA expression levels.
• U6 snRNA downregulation is a key mechanism contributing to cell death upon TDP-43 loss-of-function.
• Targeting U6 snRNA levels may offer a therapeutic strategy for TDP-43 proteinopathies.