CSF1R mutations in hereditary diffuse leukoencephalopathy with spheroids are loss of function

Area of Science:

• Neuroscience
• Genetics
• Cell Biology

Background:

• Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a rare autosomal dominant neurological disorder.
• HDLS is characterized by neuroaxonal spheroids in the central nervous system (CNS) white matter.
• Mutations in the colony-stimulating factor 1 receptor (CSF1R) gene are linked to HDLS.

Purpose of the Study:

• To investigate the functional impact of HDLS-associated CSF1R mutations on CSF1R signaling.
• To elucidate the mechanism underlying the dominant phenotype in HDLS.

Main Methods:

• Utilized a factor-dependent cell line engineered to express mutant murine Csf1r.
• Assessed Csf1r expression, CSF1 binding, and cellular proliferation in response to CSF1 stimulation.

Main Results:

• Mutant Csf1r forms were expressed at normal levels on the cell surface and bound CSF1.
• Despite normal binding, mutant Csf1r failed to sustain cell proliferation.
• These findings suggest impaired downstream signaling despite intact ligand binding.

Conclusions:

• The inability of mutant CSF1R to support cell proliferation, likely due to disrupted dimerization or downstream signaling, explains the dominant inheritance pattern in HDLS.
• This study provides a molecular mechanism for CSF1R-mediated neurodegenerative diseases.
• Targeting CSF1R signaling pathways may offer therapeutic potential for HDLS.