Polysialic acid (PSA) is important for nervous system development and maintenance, promotes cancer metastasis, tissue regeneration, and repair. Based on years of extensive experience in offering anti-glycan antibody services, Creative Biolabs can offer a full range of high-quality antibody development services against PSA to fit your specific demands in glycan identification, glycan purification or glycoantigens detection and discovery, Anti-glycan antibody diagnostics and anti-glycan antibodies in therapeutics. With the help of our professional scientists, we are confident in providing a unique antibody development service to meet every customer's requirements.
Polysialic acid (PSA) occurs as a capsular polysaccharide of neuroinvasive bacterial pathogens and as a unique glycan structure of a small set of eukaryotic cell surface proteins. In mammals, PSA consists of linear chains of α2,8-glycosidically linked N-acetylneuraminic acid residues with a variable degree of polymerization ranging from 8 up to approximately 90 sugar units and comprises approximately 10% of the total protein-bound neuraminic acid in the developing brain. In vertebrates, PSA consists of α2,8-linked N-acetylneuraminic acid and is also most prominent during nervous system development. PSA is produced by two complementary sialyltransferases, ST8SiaII and ST8SiaIV. PSA possesses excellent water solubility, low viscosity, good biocompatibility and degradation in vivo.
Fig.1 Eukaryotic PSA structure. (Hildebrandt, 2013)
PSA plays an important role in tumor invasion and recurrence. PSA has been found in various tumors, such as small cell and non-small cell lung carcinomas, neuroblastoma, multiple myeloma, rhabdomyosarcoma. The presence of PSA on the tumor cells reduced adhesion of neural adhesion molecule (NCAM), and enhanced cell motility, thus allowing the tumor cells that expressed PSA to deviate from the primary tumor and format metastases.
PSA is also critical for axon outgrowth and targeting. The presence of PSA allows limb motorneurons to defasciculate (unbundle) as they leave the spinal cord so that they can appropriately innervate different muscles. The presence of PSA is required for the migration of axons over long distances and protects them from making incorrect contacts along their path.
The presence of PSA in the adult hypothalamus has been linked to the regulation of circadian rhythms. PSA expression in the hippocampus connects to the plasticity required for memory formation and learning. Additionally, PSA is expressed in the neurohypophysis of the hypothalamus where its expression is regulated to respond to changes in the ovarian cycle, lactation, and dehydration allowing the reversible establishment of new synapses.
Studies revealed that PSA has an ability to capture biologically active molecules and that PSA regulates and controls the functions of these molecules, such as the interaction of PSA with neurotrophins, growth factors, neurotransmitters, cytokines, ions, membrane lipids, and membrane-associated proteins.
Fig.2 Overview of PSA functions. (Colley, 2014)
PSA serves as endogenous substances, which is non-immunogenic, biodegradable and biocompatible. In detail, PSA modification can reduce the immunogenicity of the proteins or polypeptides and increase circulation time of the modified drugs and carriers in the blood, thus achieving the active targeting effect.
Fig.3 The preparation of PSA decylamine derivatives and their micelles. (Zhang, 2014)
In the nervous system, PSA is present on migrating precursor cells helping them to move rapidly to their destinations and protecting them from making inappropriate contacts and differentiating prematurely. PSA is also found on the axons of neurons that must move across long distances and its presence regulates their fasciculation, sprouting and path finding. The up-regulation of PSA is observed in areas of nerve damage in both the peripheral and central nervous systems (CNS). Investigators have observed that PSA is transiently expressed on a subpopulation of astrocytes in this scar and that those axons most closely associated with these PSA expressing astrocytes exhibit more sprouting.
Serogroup B meningitis is the leading cause of meningococcal disease and septicemia in the developed world and can lead to death within 24 h. Scientists generated modified α2,8-PSA structures containing N-propionyl- rather than N-acetyl-neuraminic acid and linked these to tenanus toxoid. Then, further evaluation of this N-propionyl-2,8-PSA -tetanus toxoid vaccine in healthy male volunteers was conducted. Results showed that it increased the pre-existing IgM antibodies to group B PSA and N-propionyl-PSA, and induced IgG antibodies against N-propionyl-PSA.
The physical and biological properties of PSA make it useful in a variety of applications to improve the bioavailability of proteins used in replacement therapies. If you are interested in the PSA-related services or anti-PSA antibodies that we provide and would like to know more about the detail, just feel free to contact us. Creative Biolabs is happy to help you to make your project a success.
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