Молотковский Юлиан Георгиевич Доктор химических наук, профессор Главный научный сотрудник (лаборатория химии липидов) Тел.: +7 (495) 330-66-01 Эл. почта: jgmol@ibch.ru

Личная информация

Юл. Г. Молотковский ― сотрудник лаборатории химии липидов ИБХ с ее основания в 1963 г. Выпускник МИТХТ им. М. В. Ломоносова 1957 г, был в 1959 г. принят в аспирантуру Института химии природных соединений АН СССР в лабораторию химии антибиотиков (заведующий - академик М.М. Шемякин).

Среди работ Ю. Г. Молотковского — более 180 научных статей; Государственная премия СССР (1985 г.); он член редколлегий журналов «Биоорганическая химия» и «Биологические мембраны».

Образование

Основные научные результаты

После защиты кандидатской диссертации Ю. Г. Молотковский специализировался в липидной химии и мембранологии, в этой области ему принадлежит ряд новых разработок: методы синтеза труднодоступных фосфолипидов, новый метод разделения рацемических спиртов на антиподы, синтезы флуоресцентных и фотореактивных зондов. В сотрудничестве с отечественными и зарубежными учеными обнаружены новые закономерности в липид-белковой организации липопротеинов крови, мембран эритроцитов и вируса гриппа, изучена рецепция холерного токсина ганглиозидами, топография в мембране цитохрома Р-450, проведена серия модельных исследований бислойных мембран. После защиты докторской диссертации (1985 г.) одно из важнейших направлений лаборатории химии липидов, которой Ю. Г. Молотковский руководил с 1991 по 2007 г., ― синтезы противоопухолевых препаратов липидной природы и разработка способов направленной их доставки к опухолям.

Избранные публикации

1. Kuznetsova N., Kandyba A., Vostrov I., Kadykov V., Gaenko G., Molotkovsky J., Vodovozova E. (2009). Liposomes loaded with lipophilic prodrugs of methotrexate and melphalan as convenient drug delivery vehicles. J. Drug. Deliv. Sci. Techn. 19, 51–59 [+]

   Liposomal formulations prepared by extrusion from natural phospholipids and 1,2-dioleoylglycerol conjugates of methotrexate and melphalan (egg phosphatidylcholine–phosphatidylinositol–prodrug, 8:1:1, by mol.) were characterized by size, composition and stability. Both prodrugs were shown to incorporate completely into unilamellar liposomes with the mean size below 100 nm and form stable dispersions containing the drug concentrations relevant for systemic injections in animals. For long-term storage, the dispersions can be  subjected to deep freezing (- 196°C) and stored at - 70°C; before usage, they should be defrosted and treated shortly in an ultrasonic bath. According to the example of methotrexate conjugate, stability of prodrug ester bond in liposomal formulation towards hydrolysis by human plasma esterases during 24-h incubation were established. Also, liposomes bearing methotrexate conjugate were shown to overcome resistance of human leukemia cells related to impaired transport of initial drug across the membrane.

2. Vodovozova E.L., Pazynina G.V., Tuzikov A.B., Grechishnikova I.V., Molotkovsky J.G. (2009). Synthesis of photoreactive inorganic probes--instruments for studying membrane lectins. Bioorg. Khim. 30 (2), 174–81 [+]

   A method for the synthesis of photoaffinity neoglycolipid probes with a highly efficient carbene-generating diazocyclopentadien-2-ylcarbonyl (Dcp) label, which can be radioiodinated under standard oxidation conditions, was developed. The probes are intended for incorporation into the lipid bilayer. They are lipophilic glycoconjugates on the basis of an amphiphilic aglycone built up from a diacylglycerol and a polyethylene glycol spacer (with a polymerization degree of 9-16) bearing the Dcp label at the terminal unit. The location of the label in the aglycone provides the possibility of one-step preparation of a wide range of probes using various carbohydrate synthons. We have synthesized photoaffinity neoglycoconjugates containing the oligosaccharides: sialyl LewisX tetrasaccharide and A trisaccharide, which is specific to some tumor cells. A probe containing an inactive pentaol (aminodeoxyglucitol) was also synthesized to detect nonspecific binding. The Dcp label is bound to the probe molecule by ester bond; its lability under alkaline conditions facilitates the analysis of cross-linked products after photoaffinity labeling. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.

3. Boldyrev I.A., Zhai X., Momsen M.M., Brockman H.L., Brown R.E., Molotkovsky J.G. (2007). New BODIPY lipid probes for fluorescence studies of membranes. J. Lipid Res. 48 (7), 1518–32 [+]

   Many fluorescent lipid probes tend to loop back to the membrane interface when attached to a lipid acyl chain rather than embedding deeply into the bilayer. To achieve maximum embedding of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) fluorophore into the bilayer apolar region, a series of sn-2 acyl-labeled phosphatidylcholines was synthesized bearing 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene-8-yl (Me(4)-BODIPY-8) at the end of C(3)-, C(5)-, C(7)-, or C(9)-acyl. A strategy was used of symmetrically dispersing the methyl groups at BODIPY ring positions 1, 3, 5, and 7 to decrease fluorophore polarity. Iodide quenching of the phosphatidylcholine probes in bilayer vesicles confirmed that the Me(4)-BODIPY-8 fluorophore was embedded in the bilayer. Parallax analysis of Me(4)-BODIPY-8 fluorescence quenching by phosphatidylcholines containing iodide at different positions along the sn-2 acyl chain indicated that the penetration depth of Me(4)-BODIPY-8 into the bilayer was determined by the length of the linking acyl chain. Evaluation using monolayers showed minimal perturbation of <10 mol% probe in fluid-phase and cholesterol-enriched phosphatidylcholine. Spectral characterization in monolayers and bilayers confirmed the retention of many features of other BODIPY derivatives (i.e., absorption and emission wavelength maxima near 498 nm and approximately 506-515 nm) but also showed the absence of the 620-630 nm peak associated with BODIPY dimer fluorescence and the presence of a 570 nm emission shoulder at high Me(4)-BODIPY-8 surface concentrations. We conclude that the new probes should have versatile utility in membrane studies, especially when precise location of the reporter group is needed.

4. Vodovozova E.L., Tsibizova E.V., Molotkovsky J.G. (2001). One-step iodination of the diazocyclopentadien-2-ylcarbonyl group—a new and convenient preparation of effective radiolabelled photoaffinity probes. J. Chem. Soc., Perkin Trans. 1  (200), 2221–2228 [+]

   A detailed study devoted to direct iodination of the photoactivatable diazocyclopentadien-2-ylcarbonyl (Dcp) group is presented. The iodination does not influence the high carbene reactivity of the Dcp-generated carbene. It was shown that the Dcp substituent forms 4-mono-, 5-mono- and 4,5-diiododerivatives upon iodination under oxidative conditions (76, 20 and 4%, respectively, when DcpOMe 2 is iodinated). Photolysis of the individual products of iodination in cyclohexane resulted in rather high insertion into non-activated CH bonds, without noticeable loss of iodine. Syntheses of new phospholipid and ganglioside membrane probes are also described which incorporate the Dcp function via a labile ester bond. A [125I]-Dcp-phosphatidylcholine probe exhibiting high specific radioactivity (∼500 Ci mmol
   1) was easily prepared at yields of 90% (on the starting Na125I), by using peracetic acid as an oxidant.
   Furthermore, it was successfully used for photolabelling of the integral protein hemagglutinin in a well-characterised influenza virus model. In summary, the Dcp group is efficient for labelling a wide variety of molecules, and as such, it provides a new tool for exploring a diverse range of biological systems.

5. Vodovozova E.L., Moiseeva E.V., Grechko G.K., Gayenko G.P., Nifant'ev N.E., Bovin N.V., Molotkovsky J.G. (2000). Antitumour activity of cytotoxic liposomes equipped with selectin ligand SiaLe(X), in a mouse mammary adenocarcinoma model. Eur. J. Cancer 36 (7), 942–9 [+]

   The overexpression of lectins by malignant cells compared with normal ones can be used for the targeting of drug-loaded liposomes to tumours with the help of specific carbohydrate ligands (vectors). Recently we have shown that liposomes bearing specific lipid-anchored glycoconjugates on a polymeric matrix bind in vitro to human malignant cells more effectively and, being loaded with a lipophilic prodrug of merphalan, reveal higher cytotoxic activity compared with unvectored liposomes. In this study, carbohydrate-equipped cytotoxic liposomes were tested in vivo in a mouse breast cancer model, BLRB-Rb (8.17)1Iem strain with a high incidence of spontaneous mammary adenocarcinoma (SMA). Firstly, a cell line of the SMA was established which was then used to determine the specificity of the tumour cell lectins. After screening of the lectin specificity of a number of fluorescent carbohydrate probes, SiaLe(X) was shown to be the ligand with the most affinity, and a lipophilic vector bearing this saccharide was synthesised. Then different liposomal formulations of the synthetic merphalan lipid derivative and SiaLe(X) vector were prepared and applied in the treatment of mice with grafted adenocarcinomas. The results of the tumorigenesis data show that the therapeutic efficacy of merphalan increases sharply after its insertion as a lipophilic prodrug into the membrane of SiaLe(X)-vectored liposomes.

6. Vodovozova E.L., Gayenko G.P., Razinkov V.I., Korchagina E.Y., Bovin N.V., Molotkovsky J.G. (1998). Saccharide-assisted delivery of cytotoxic liposomes to human malignant cells. Biochem. Mol. Biol. Int. 44 (3), 543–53 [+]

   The overexpression of lectins by malignant cells was applied for in vitro targeting of liposomes equipped with a saccharide vector and loaded in the lipid phase with a lipid derivative of anticancer agent sarcolysine. The lectin specificity of human leukemia HL-60 and human lung adenocarcinoma ACL cells was revealed by tests with fluorescein-labeled sugar probes. With the help of fluorescent lipid dye it was shown that active saccharide ligands increased the level of the vectored liposome binding to malignant cells by 50-80% as compared to liposomes without vector or with inactive one. The degree of liposome/cell membrane fusion was monitored fluorometrically and was shown to be complete and independent of the vectors. The targeted drug-loaded liposomes had the cytotoxic activity 2-4 times higher as compared to the vector-free ones.

7. Bergelson L.D., Molotkovsky J.G., Manevich Y.M. (1985). Lipid-specific fluorescent probes in studies of biological membranes. Chem. Phys. Lipids 37 (2), 165–95 [+]

   Lipid-specific fluorescent probes are natural lipids carrying an apolar fluorophore in one of the hydrocarbon chains. Since such probes retain the head groups and resemble the molecular shape of native membrane lipids, they largely mimic the behaviour of their natural prototypes in biological membranes. Information provided by the lipid-specific probes is more differentiated and easier to interpret than that obtained from non-lipid probes. The principles of design of lipid-specific probes are formulated and the relative advantages and disadvantages of various fluorophores are discussed. In order to reduce ambiguities caused by perturbation of the probe environment, it is proposed to use, in a comparative manner, two or more lipid-specific probes resembling each other in all aspects except the polar head groups (the 'two probes' concept). Two types of fluorophores, the anthrylvinyl group and the perylenoyl group, were found to be well suited for the synthesis of lipid-specific probes. Use of both types of probes 'in tandem' opens new possibilities for studying lipid-protein and lipid-lipid interactions in biological membranes. The anthrylvinyl- and perylenoyl-labeled lipids were applied in studies of serum lipoproteins and erythrocyte membranes. A new highly sensitive ligand-receptor binding assay and a new approach to biological signal amplifying based on the use of lipid-specific probes are described.

8. Molotkovsky J.G., Manevich Y.M., Babak V.I., Bergelson L.D. (1984). Perylenoyl- and anthrylvinyl-labeled lipids as membrane probes.  (778), 281–288
9. Molotkovsky J.G., Bergelson L.D. (1973). Synthesis of unsaturated mixed acid phosphatidylinositol of natural configuration. A new procedure for resolving racemic alcohols.  (11), 135–147