Nuclear Import Defects Drive Cell Cycle Dysregulation in Neurodegeneration

Area of Science:

• Neuroscience
• Cell Biology
• Aging Research

Background:

• Neurodegenerative diseases (NDDs) share hallmarks like cell cycle dysregulation (CCD) and nucleocytoplasmic transport (NCT) defects.
• The causal role of CCD and NCT defects in aging and NDDs remains debated.
• Aberrant cell cycle activation in neurons can trigger cell death and senescence, while NCT defects lead to protein redistribution, driving NDDs.

Purpose of the Study:

• To investigate the functional significance of NCT defects in neurodegeneration.
• To determine if impaired nuclear import can induce cell cycle machinery perturbation.
• To explore the link between nuclear import defects, CCD, and NDD pathology.

Main Methods:

• Pharmacological inhibition of importin-β nuclear import in neuronal cell lines and primary neurons.
• Utilized a novel Nemf^R86S mouse model exhibiting nuclear import defects.
• Assessed cell cycle machinery perturbation, CCD hallmarks, and transcriptional/phenotypical dysregulation in vitro and in vivo.

Main Results:

• Pharmacological inhibition of importin-β disrupted cell cycle machinery in both mitotic and post-mitotic neurons.
• The Nemf^R86S mouse model recapitulated CCD hallmarks in various neuronal types and spinal motor neurons.
• Observed CCD correlated with transcriptional and phenotypical dysregulation seen in neuronal cell death and senescence in NDDs.

Conclusions:

• Impairment of nuclear import pathways can perturb neuronal cell cycle machinery.
• Nuclear import defects leading to cell cycle dysregulation may be a common driver of neurodegeneration.
• This study provides evidence linking NCT defects to CCD as a shared pathological mechanism in NDDs.