International Journal of Neurology Research Online Submissions: http://www.ghrnet.org/index./ijnr/ Int. J. Neurology Res. 2017 September; 3(2): 338-348 doi:10.17554/j.issn.2313-5611.2017.03.64 ISSN 2313-5611 REVIEW Neurolectins: Biochemical Characterisation and Functions Nugzar Aleksidze Nugzar Aleksidze, Andrewthe of Georgia first Called the Georgian and immunotoxic, can be avoided by means of well toasted bread, University of Patriarchate of Gorgia, Member of the Georgian Na- because in the process of toasting, lectins undergo denaturation and tional Academy of Sciences lose their toxic activity. Food should be chewed well, until it becomes saturated with glycoprotein mucine, which is component of saliva, as Conflict-of-interest statement: The author(s) declare(s) that there N-acetyl-D-glucosamine binding and inactivating WGA is presented is no conflict of interest regarding the publication of this paper. in its active centre. In conclusion it is said that uptake of food additives offered by D’Adamo, with the ability of binding WGA and Open-Access: This article is an open-access article which was other neurolectins, is not recommended for teenagers and pregnant selected by an in-house editor and fully peer-reviewed by external women, as they may cause inhibition of key processes, involved in reviewers. It is distributed in accordance with the Creative Com- mechanisms of structural-functional organization of brain. mons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non- Key words: neurolectins, brain, sinaptosoms, neurons, glial cells, commercially, and license their derivative works on different terms, synaptic vesicles, mitochondrion, nuclear, glicoconjugates, migration, provided the original work is properly cited and the use is non- thermoregulation. commercial. See: http: //creativecommons.org/licenses/by-nc/4.0/ Aleksidze N. Neurolectins: Biochemical Characterisation and Func- Correspondence to: Nugzar Aleksidze, St. Andrewthe First Called tions. International Journal of Neurology Research 2017; 3(2): 338- Georgian University of Patriarchate of Georgia 348 Available from: URL: http: //www.ghrnet.org/index.php/jnr/ Email: [email protected] article/view/1966 Telephone: +995 579 973807 INTRODUCTION Received: January 12, 2017 Lectinology as a new direction of science has started to develop in- Revised: May 22, 2017 tensively. Lectins are selectively and reversibly bound with carbohy- Accepted: May 24, 2017 drates and are the cause of agglutination in cells and tissues. They ac- September 11, 2017 Published online: tively participate in such vital processes as communication, signaling systems, adhesion, structural organization, etc. Lectins are proteins of ABSTRACT low-molecular glycoproteinic nature and are distinguished by multi- functional activity. Emerging from the functions of lectins there are The presented work deals with the recent achievements in the field of great perspectives for their use in medicine and biology [1-7]. The anti- research of neurolectins, their quantitative and qualitative distribution cancer, antiallergic and immunomodulatory properties of lectins have in cerebral cells of different animals, subcellular structures and already found practical application in clinical medicine for diagnosis synaptosomes in relation to embryonic development. Distribution of and treatment of infectious diseases[8-19]. Lectins are also effectively neurolectin-binding receptors glycoproteins and glycolipids in the used in biochemical and histochemical investigations. It has become same structures, their role in the processes of migration of neurons and possible to isolate and purify glycoproteins and glycolipids via lec- other mechanisms are studied as well. Two membrane neurolectins tine probe of terminal carbohydrates within biomembranes[20-26]. VL-1 and VL-NAGA have been revealed in synaptosomes, which according to our hypothesis are actively involved in absorption and secretion of neurotransmitters. It was established that VL-1, located RESULTS on the outer membrane of synaptosomes participates in absorption The first protein with agglutination capacity was discovered in 1888 and metabolism of biologically active substances, though VL-NAGA, by a doctorant of Tartu University Peter Herman Stilmark in the which is located in the inner side of the membrane, is also involved seeds and oils of the plant Ricinus communis and was called Ricin. in their metabolism. It is considered that negative effects of wheat As this substance caused agglutination of erythrocytes it became germ agglutinin (WGA) lectins, among them neurotoxic, cardiotoxic known as hemagglutinin. Unfortunately Ricin appeared to be a potent 338 Aleksidze N. Neurolectins toxic substance commonly employed for committing terrorist acts. were found in the lateral parts of Laminae V-VII. RL-29 lectin is a The first terrorist act was carried out in 1978 on the Waterloo bridge multipolar reactive product revealed in the primary and secondary in London where a Bulgarian oppositioner Georgi Markov was killed dendrites and some axons. The results suggest that the neuropathic by pricking an umbrella tip treated with Ricin. This terrorist act injury produces a long term transsynaptic change in a subpopulation became known as “killing with an umbrella”. Later on it appeared of the dorsal horn neurons, which is mediated by excitatory amino that killing with Ricin was due to the inhibition of protein synthesis acid transmitters acting at NMDA receptors. These data show that on the ribosome’s level. the majority of RL-29 IR neurons in the parasympathetic nucleus are It is well known that the majority of agglutinins show particular autonomic preganglionic neurons, thus suggesting that RL-29 can be sensitivity towards hydrogen ions, extractive solutions, detergents, a useful tool in marking this subpopulation neurons[45]. sugars and inorganic ions. It is notable that agglutinin extracted Detection of neurolectins at different stages of embryonic from the rat brain glial cells with 0.5 mM EDTA has specific affinity development became the subject of our great interest. Firstly, in order towards glucose, mannose and inositol, whereas the agglutinin to reveal maximal neurolectin activity in an embryonic and adult hen extracted with potassium phosphate buffer (PPB) was specific for brain, a various compositions of extracting solutions were tested, galactose and inositol. Lectin isolated from the rat brain with 5 mM among them most perspective appeared 0.5 mM EDTA potassium EDTA was found to be sensitive to glucose, fructose, ribose and phosphate buffer (PPB), for further purification of which from 0 mannose. It is noteworthy that their pH optimum ranges from 7.0 to to 80% saturated ammonium sulfate solution was used. It has been 8.0. shown that only on 5th day of embryonic development of hen brain Since the discovery of proteins with agglutination ability neurolectin activity was revealed and it reached its maximum before hemagglutinins in animal organisms are referred to lectins[27], we call hatching[46-48]. neurolectins those ones which are separated from nervous tissues[28]. Noteworthy results were obtained while studying the neurolectin The first neurolectin was isolated from the electric organ of distribution in the rat brain P1 and P2 fractions during 2-16 days [49] Electrophorus electricus by Teichberg et al.(1975). It agglutinates before its hatching . P1 and P2 fractions were obtained according trypsin-treated rabbit erythrocytes and is specifically inhibited by to Teichberg et al[29]. P fractions were dissolved in the 0.5 mM disaccharides containing non reducing terminal beta-D-galactosyl EDTA and homogenized. The Sediment was dissolved in PPB, residues[29]. It was called electrolectin. Electrolectin was partially prepared with sodium chloride and explored lectin activity[50-52]. It membrane-bound, but it was also found in soluble fractions of was stated that the rat brain P1 and P2 fractions were characterized by electric organ homogenates. The neurolectin was purified by affinity agglutinating activity. Much higher activity is predominantly detected th chromatography on cross-linked and disulfated agarose (ECD- on 7 day of embryonal development in P2 protein fraction. If Sepharose) as a protein of molecular weight 33 kDa. Electrolectin neurolectin specific activity in dose days in 1P and P2 fractions were in large amounts was found in the microsomal fraction of electric 79,37 and 132,50 unit, before hatching this index reduces maximally organ, obtained via 70 min 100000 g centrifugation. Electrolectin and is no more than 16,04 and 80,62 unit respectively. A contention amount made up 11% of total proteins. It has been calculated that is expressed that lectin activity reduction can not be accounted by a electrolectin’s amount per 1 kg electric organ is 400 mg, that is decrease in neurolectin’s total amount, but by the increase of brain rather high index, bearing in mind that the amount of one of the dry mass and volume[48,51,52]. Similar view has been offered by other most essential enzymes acetylcholinestherase in 1 kg of nervous authors as well[36,50-52]. tissue does exceed 50-100 mg, whereas the number of acetylcholine The study was pursued of the neurolectin content in the hen receptors fluctuates within 5-10 mg/kg[30]. Recently it has been found brain at embryonic and postembryonic development. Neurolectin out that galactose-specific lectin is extensively distributed in