Metabolomic Profiling Reveals Brain Lipid Alterations in PEX7-Deficient Models of Rhizomelic Chondrodysplasia...

Area of Science:

• Biochemistry
• Genetics
• Neuroscience

Background:

• Rhizomelic chondrodysplasia punctata type 1 (RCDP1) is a severe peroxisomal disorder caused by PEX7 variants.
• It is characterized by skeletal abnormalities, intellectual disability, seizures, and cataracts, with plasmalogen deficiency as a key feature.
• Other peroxisomal disorders like RCDP types 2-5 and Zellweger spectrum disorders also exhibit plasmalogen deficiency.

Purpose of the Study:

• To investigate the neurometabolic consequences of PEX7 deficiency in RCDP1.
• To compare lipid profiles in the central nervous system (CNS) versus plasma of affected individuals and animal models.
• To identify novel insights into the pathogenesis of neurological dysfunction in RCDP.

Main Methods:

• Comprehensive metabolomic profiling of clinical samples from RCDP patients.
• Analysis of Pex7-deficient mouse models to assess CNS and plasma lipid alterations.
• Focus on lipid classes including phosphatidylethanolamines (PEs), phosphatidylcholines (PCs), acylcarnitines, and sphingomyelins.

Main Results:

• Profound neurometabolic disturbances were identified in the cerebral cortex and cerebellum of Pex7-deficient mice.
• Multiple lipid classes, including PEs, PCs, acylcarnitines, and sphingomyelins, were significantly altered in the brain.
• Many of these CNS lipid alterations were not detected in the plasma of patients or Pex7-deficient mice.

Conclusions:

• Plasma metabolomic profiling may underestimate the extent of CNS lipid remodeling in RCDP.
• Plasmalogen deficiency leads to complex neurometabolic adaptations in the brain.
• Additional pathways beyond plasmalogen synthesis may contribute to neurological dysfunction in RCDP.