cérébrosides

Cerebrosides are a class of neutral glycosphingolipids composed of a ceramide molecule linked to a single sugar residue, either glucose or galactose. They are among the simplest glycosphingolipids and contain no sialic acid. The two principal cerebrosides are glucocerebroside and galactocerebroside, in contrast to more complex glycosphingolipids such as gangliosides that carry multiple sugar units and sialic acid.

Chemically, ceramide forms the hydrophobic backbone, created by a fatty acid attached to sphingosine. The sugar head group attaches via a glycosidic bond, yielding a molecule with a hydrophilic head and a hydrophobic tail. Cerebrosides are widely distributed in tissues but are especially abundant in the nervous system, with galactocerebroside a major constituent of central nervous system myelin.

Functionally, cerebrosides contribute to the structural integrity of cell membranes and myelin sheaths, influencing membrane fluidity and organizational microdomains. They also participate in cellular signaling and recognition processes, and may affect interactions between cells and the extracellular environment.

Metabolism and clinical relevance: cerebrosides are degraded in lysosomes by specific hydrolases. Galactocerebrosidase breaks down galactocerebroside, while glucocerebrosidase degrades glucocerebroside. Deficiencies in these enzymes cause lysosomal storage disorders. For example, galactocerebrosidase deficiency leads to Krabbe disease, characterized by demyelination and neurodegeneration, whereas glucocerebrosidase deficiency causes Gaucher disease, marked by glucocerebroside accumulation in macrophages. Treatments exist for Gaucher disease, and research into therapies for Krabbe disease, including gene and enzyme-based approaches, is ongoing.