scholarly journals Protective effects of polysialic acids (PSAs) and its mimics on the nervous system after injury

2021 ◽  
Vol 26 (4) ◽  
pp. 643-647
Author(s):  
Wei-jiang Zhao ◽  
Jia-hui He ◽  
Shuang-xi Chen

Polysialic acid (PSA), a polymer of alpha-2,8 linked sialic acid residues, is a negatively charged macromolecular glycan mainly attached to neural cell adhesion molecules (NCAM). Studies have shown that PSA is not only essential for the development of normal brain circulation, but also for synaptic plasticity, learning and memory in adults. Although the occurrence, features, biosynthesis, and physiological roles of PSA and related effects on related diseases, including schizophrenia, bipolar disorder, neurodegenerative diseases and cancer, have been well reviewed, the important roles of PSA and its mimics in the regeneration of the nervous system following injury have not been well discussed. As a consequence, this article comprehensively reviews the effects of small organic compounds that simulate PSA, such as tegaserod and 5-nonyloxytryptamine (5-NOT), on the nervous system of mammals, suggesting that these mimetics may have tremendous therapeutic potential, especially for strategies aimed at tissue repair after injury of the nervous system.

2020 ◽  
Vol 21 (22) ◽  
pp. 8593
Author(s):  
Yi Yang ◽  
Ryo Murai ◽  
Yuka Takahashi ◽  
Airi Mori ◽  
Masaya Hane ◽  
...  

Polysialic acid (polySia/PSA) is a linear homopolymer of sialic acid (Sia) that primarily modifies the neural cell adhesion molecule (NCAM) in mammalian brains. PolySia-NCAM not only displays an anti-adhesive function due to the hydration effect, but also possesses a molecule-retaining function via a direct binding to neurologically active molecules. The quality and quantity of polySia determine the function of polySia-NCAM and are considered to be profoundly related to the maintenance of normal brain functions. In this study, to compare the structures of polySia-NCAM in brains of five different vertebrates (mammals, birds, reptiles, amphibians, and fish), we adopted newly developed combinational methods for the analyses. The results revealed that the structural features of polySia considerably varied among different species. Interestingly, mice, as a mammal, possess eminently distinct types of polySia, in both quality and quantity, compared with those possessed by other animals. Thus, the mouse polySia is of larger quantities, of longer and more diverse chain lengths, and of a larger molecular size with higher negative charge, compared with polySia of other species. These properties might enable more advanced brain function. Additionally, it is suggested that the polySia/Sia ratio, which likely reflects the complexity of brain function, can be used as a new promising index to evaluate the intelligence of different vertebrate brains.


1995 ◽  
Vol 12 (6) ◽  
pp. 829-837 ◽  
Author(s):  
Ellen W. Easton ◽  
Wietske E. C. M. Schiphorst ◽  
Carolien A. M. Koeleman ◽  
Rob J. A. M. Michalides ◽  
Dirk H. van den Eijnden

2018 ◽  
Vol 25 (14) ◽  
pp. 1663-1681 ◽  
Author(s):  
Chun-Ting Lee ◽  
Heng-Chun Kuo ◽  
Yung-Hsiang Chen ◽  
Ming-Yen Tsai

The polysaccharides in many plants are attracting worldwide attention because of their biological activities and medical properties, such as anti-viral, anti-oxidative, antichronic inflammation, anti-hypertensive, immunomodulation, and neuron-protective effects, as well as anti-tumor activity. Denodrobium species, a genus of the family orchidaceae, have been used as herbal medicines for hundreds of years in China due to their pharmacological effects. These effects include nourishing the Yin, supplementing the stomach, increasing body fluids, and clearing heat. Recently, numerous researchers have investigated possible active compounds in Denodrobium species, such as lectins, phenanthrenes, alkaloids, trigonopol A, and polysaccharides. Unlike those of other plants, the biological effects of polysaccharides in Dendrobium are a novel research field. In this review, we focus on these novel findings to give readers an overall picture of the intriguing therapeutic potential of polysaccharides in Dendrobium, especially those of the four commonly-used Denodrobium species: D. huoshanense, D. offininale, D. nobile, and D. chrysotoxum.


2018 ◽  
Vol 25 (28) ◽  
pp. 3333-3352 ◽  
Author(s):  
Natalia Pessoa Rocha ◽  
Ana Cristina Simoes e Silva ◽  
Thiago Ruiz Rodrigues Prestes ◽  
Victor Feracin ◽  
Caroline Amaral Machado ◽  
...  

Background: The Renin-Angiotensin System (RAS) is a key regulator of cardiovascular and renal homeostasis, but also plays important roles in mediating physiological functions in the central nervous system (CNS). The effects of the RAS were classically described as mediated by angiotensin (Ang) II via angiotensin type 1 (AT1) receptors. However, another arm of the RAS formed by the angiotensin converting enzyme 2 (ACE2), Ang-(1-7) and the Mas receptor has been a matter of investigation due to its important physiological roles, usually counterbalancing the classical effects exerted by Ang II. Objective: We aim to provide an overview of effects elicited by the RAS, especially Ang-(1-7), in the brain. We also aim to discuss the therapeutic potential for neuropsychiatric disorders for the modulation of RAS. Method: We carried out an extensive literature search in PubMed central. Results: Within the brain, Ang-(1-7) contributes to the regulation of blood pressure by acting at regions that control cardiovascular functions. In contrast with Ang II, Ang-(1-7) improves baroreflex sensitivity and plays an inhibitory role in hypothalamic noradrenergic neurotransmission. Ang-(1-7) not only exerts effects related to blood pressure regulation, but also acts as a neuroprotective component of the RAS, for instance, by reducing cerebral infarct size, inflammation, oxidative stress and neuronal apoptosis. Conclusion: Pre-clinical evidence supports a relevant role for ACE2/Ang-(1-7)/Mas receptor axis in several neuropsychiatric conditions, including stress-related and mood disorders, cerebrovascular ischemic and hemorrhagic lesions and neurodegenerative diseases. However, very few data are available regarding the ACE2/Ang-(1-7)/Mas receptor axis in human CNS.


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