Nuclear Receptor NR1H3 in Familial Multiple Sclerosis

Area of Science:

• Neuroimmunology
• Genetics
• Molecular Biology

Background:

• Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system.
• Pathogenic genetic mutations contributing to MS pathogenesis, particularly in familial cases, remain largely unidentified.
• Understanding the genetic underpinnings of MS is crucial for developing targeted therapies.

Purpose of the Study:

• To identify pathogenic mutations associated with severe, progressive multiple sclerosis in familial cohorts.
• To investigate the functional consequences of identified genetic variants in NR1H3.
• To explore potential therapeutic strategies targeting the NR1H3 pathway for progressive MS.

Main Methods:

• Whole-exome sequencing and targeted gene analysis in affected individuals from multi-incident MS families.
• Functional studies including protein interaction assays, reporter gene assays, and gene expression profiling.
• Association analysis of common NR1H3 variants with MS risk.

Main Results:

• Identification of a novel NR1H3 p.Arg415Gln mutation in seven MS patients from two families with severe, progressive disease.
• The NR1H3 p.Arg415Gln mutation disrupts NR1H3 (LXRA) heterodimerization and transcriptional activity.
• Association of common NR1H3 variant rs2279238 with a 1.35-fold increased risk for progressive MS.
• Mutant NR1H3 alters gene expression profiles, indicating disrupted transcriptional regulation.

Conclusions:

• The NR1H3 gene, specifically the p.Arg415Gln variant, plays a significant role in the pathogenesis of severe, progressive multiple sclerosis.
• Disruption of NR1H3-mediated transcriptional regulation is a key mechanism in MS.
• Targeting LXRA or its downstream pathways presents a promising therapeutic avenue for progressive MS.