Heparan sulfate is a molecule present in the human body and in all animals. It is a polysaccharide related to the extracellular matrix and the cell surface of proteins, as well as to the cellular energy cycle and growth signals.
Heparan sulfate, what it is
Classified as a polysaccharide, its function is to serve as an energy and structural reserve for animal tissues. Among polysaccharides, heparan sulfate is a proteoglycan that binds to various proteins in the human body, carrying out multiple biological functions.
It is also part of the carbohydrates of mucopolysaccharides or glycosaminoglycans and is found in large quantities in the lungs, liver, and major arteries of the human body, such as the aorta.
Contents
Proteoglycans
Within the group of proteoglycans, they are found in the extracellular matrix and basal membrane, with nuclear proteins called agrin, multidomain perlecans, and type XVIII collagen containing the highest amounts. At the same time, smaller forms are defined as HSPG, betaglycans, and the V-3 isoform of CD44.
The major forms of heparan sulfates are glypicans and transmembrane syndecans. Glypicans are anchored to glycosylphosphatidylinositol.
Function of heparan sulfate
One of the key properties of heparan sulfate is its role in angiogenesis, the formation of new blood vessels using existing ones as a route.
Its structure is also essential for blood clotting. This property allows the body’s circulatory system to close wounds through platelet aggregation.
The type of heparan sulfate known as HSPG is believed to play a significant role in degenerative diseases such as Alzheimer’s and Parkinson’s.
Cells require signals to duplicate and promote tissue growth. These signals, in the form of growth factors from proteins, bind to the cell surface. This facilitates the connection between protein growth factors and cells, prompting a response accordingly.
Differences between heparan sulfate and heparin
Both are classified as biomolecules, and although they have similar chemical structures, they serve different functions and have distinct medical applications.
Heparan sulfate is a carbohydrate belonging to glycosaminoglycans. It consists of glucuronic acid (GlcA) and N-acetylglucosamine (GlcNAc).
On the other hand, heparin, although very similar, is often difficult to distinguish. It has a higher concentration of N-sulfate groups compared to N-acetyl groups. Additionally, one way to identify it is that the concentration of O-sulfate groups exceeds that of N-sulfate groups.
Its formation in the body follows different pathways, initiating synthesis as needed—for instance, increasing levels of heparan sulfate, chondroitin sulfate, heparin, or dermatan sulfate. This biochemical and biological process is regulated by the enzyme GlcNAcT and GalNAcTI.
Relationship with leptin
Leptin is a peptide produced and released by adipocytes, or fat cells. Its function is to send a signal to stop eating and start burning energy. The higher the leptin levels, the stronger the body’s response to fat storage. It is directly related to the percentage of body fat and how it is stored.
The entire filtration process occurs in the liver and kidneys, where these types of sulfated molecules are most abundant. The absorption of leptin from food will be more effective depending on the amount of heparan sulfate present in the body.
