The Cerebrosides Are a group of glycosphingolipids that function within the human and animal body as components of the muscular and nerve cell membranes, as well as the general nervous system (central and peripheral).
Within the sphingolipids, cerebrosides are also given the formal name of monoglycosylceramides.
Β-D-Galactosylceramide, a galactocerebroside.
These molecular components are found in abundance in the myelin sheath of the nerves, which is a multilaminar coating made up of protein components that surround the neuronal axons in the Human nervous system .
Cerebrosides are part of the large group of lipids that work within the nervous system. The group of sphingolipids play an important role as components of membranes, regulating their dynamics and forming part of their internal structures with their own functions.
Apart from cerebrosides, other sphingolipids have been shown to be of great importance for the transmission of neuronal signals and recognitions on the cell surface.
The cerebrosides were discovered together with the group of other sphingolipids by the German Johann L. W. Thudichum in 1884. At that time the function that these specifically fulfilled could not be found, but we began to have an idea about the structures that formed these molecular compounds.
In humans, wear and tear of lipid components such as cerebrosides can cause dysfunctional diseases that can affect other organs of the body.
Diseases such as Bubonic Plague or Black Death have been attributed to symptoms caused by the deterioration and degradation of galactosylcerebrosides.
Structure of the brainsids
The most important and fundamental element in the structure of cerebrosides is ceramide, a family of lipids composed of fatty acids and carbon variations that serve as the base molecule for the rest of the sphingolipids.
Because of this, the denominations of the different types of cerebrosides have ceramide in the name, like glucosilceramidas (glucosilcerebrósidos) or galactosilceramidas (galactosilcerebrósidos).
Cerebrosides are considered monosaccharides. A residual sugar is attached to the ceramide molecule that composes them through a glucosidic bond.
Depending on whether the sugar unit is glucose or galactose, two types of cerebrosides can be generated: glucosylcerebrosides (glucose) and galactosylcerebrosides (galactose).
Of these two types, the glucosylcerebrosides are those whose monosaccharide residue is glucose and are usually found and distributed in non-neuronal tissue.
Its excessive accumulation in one place (cells or organs) gives rise to the symptoms of Gaucher disease, which generates conditions such as fatigue, anemia and hypertrophy of organs such as the liver.
Galactosylcerebrosides have a similar composition as above, except for the presence of galactose as a residual monosaccharide instead of glucose.
These are usually distributed across all neural tissues (representing 2% gray matter and up to 12% white matter) and serve as markers for the functioning of oligodentrocytes, cells responsible for myelin formation.
The glycosylcerebrosidos and galactosilcebrosidos can also be differentiated by the types of fatty acids that present their molecules: lignocérico (kerosine), cerebrónico (frenosina), nervónico (nervón), oxinervónico (oxinervón).
Cerebrosides can complement their functions in the company of other elements, especially in non-neuronal tissues.
An example of this is the presence of glucosylcerebrosides in the lipids of the skin, which help ensure the permeability of the skin against water.
Synthesis and properties of cerebrosides
The formation and synthesis of cerebrosides is performed by a process of adhesion or direct transfer of sugar (glucose or galactose) from a nucleotide to the ceramide molecule.
The biosynthesis of glycosylcerebrosides or galactosylcerebrosides occurs in the endoplasmic reticulum (of a eukaryotic cell) and in the membranes of the Golgi apparatus.
Physically, cerebrosides have manifested their own thermal attributes and behaviors. They usually have a melting point much higher than the average temperature of the human body, presenting a structure of liquid crystal.
Cerebrosides have the ability to make up to eight hydrogen bonds from the base elements of ceramide, such as sphingosine.
This creation allows a higher level of compaction between the molecules, generating own internal temperature levels.
Together with substances such as cholesterol, cerebrosides help in the integration of proteins and enzymes.
The natural degradation of cerebrosides consists of a process of deconstruction or separation of its components. It takes place in the Lysosome , Responsible for separating the cerebroside into sugar, sphingosine and fatty acid.
Cerebrosides and diseases
As mentioned above, the erosion of cerebrosides, as well as their excessive accumulation in a single place of the human and animal cellular and organic system can generate affections that in the moment could end up with a third of the continental population, in Europe , for example.
Some of the diseases caused by defects in the functioning of cerebrosides are considered hereditary.
In the case of Gaucher disease, one of its main causes is the absence of glucocerebrocidasa, an enzyme that allows to counteract the accumulation of fats.
This disease is not considered to have a cure, and in some cases, its early appearance (in newborns, for example) is almost always fatal.
Another of the most common diseases, resulting from defects in galactosylcerebrosides, is the Krabbe disease , Which is defined as a dysfunctional failure of the lysosomal deposit, which generates an accumulation of galactosylcerebrosides that affect the myelin sheath, and therefore the white matter of the nervous system, causing a degenerative disorder without brake.
Considered hereditary, it can be born with Krabbe's disease and begin to manifest symptoms between the first three and six months of age.
The most common are: limb stiffness, fever, irritability, seizures and slow development of motor and mental abilities.
Krabbe's disease can also lead to more severe distress, such as muscle weakness, deafness, optic atrophy, blindness, and paralysis.
A cure has not been determined, although bone marrow transplantation is considered to aid in treatment. Children at an early age have a low level of survival.
References
- Medline Plus. (S.f.). Gaucher disease . Retrieved from Medline Plus: medlineplus.gov
- O'Brien, J. S., & Rouser, G. (1964). The fatty acid composition of brain sphingolipids: sphingomyelin, ceramide, cerebroside, and cerebroside sulfate. Journal of Lipid Research , 339-342.
- O'Brien, J.S., Fillerup, D.L., & Mead, J.F. (1964). Brain lipids: I. Quantification and fatty acid composition of cerebroside sulfate in human cerebral gray and white matter. Journal of Lipid Research , 109-116.
- Office of Communications and Public Liaison; National Institute of Neurological Disorders and Stroke; National Institutes of Health. (December 20, 2016). Lipid Storage Diseases Information Page . Retrieved from the National Institute of Neurological Disorders and Stroke: ninds.nih.gov
- Ramil, J. S. (s.f.). Lipids.