Ivan A. Boldyrev


PeriodCountry, cityEducation institutionAdditional info
1998–2004 Moscow Moscow State Academy of Fine Chemical Technology Ingineer (Biotechnology)
2004–2007 Moscow Institute of Bioorganic Chemistry postgraduate studentship

Selected publications

  1. Алексеева А.С., Третьякова Д.С., Мельникова Д.Н., Молотковский Юл.Г., Болдырев И.А. (2016). Новый флуоресцентный мембранный зонд (2,3;5,6 бисциклогексил)bodipy меченный фосфатидилхолн. Биоорг. хим. 42 (3), 339–344 [+]

    Новый мембранный зонд бисциклогексил BODIPY (BCHB) меченный фосфатидилхолин структурно очень близок в 1,3,5,7 тетраметил BODIPY (TMB) меченному фосфатидилхолину и синтезируется по аналогичной схеме. Системы сопряженных связей BCHB и TMB формально идентичны, однако спектральные характеристики BCHB заметно отличаются, что делают BCHB хорошим акцептором фёрстеровского резонансного переноса (FRET) для TMB. Показано, что FRET пара фосфатидилхолинов на основе BCHB и TMB является перспективным инструментом для исследования мембранных систем, например, межмембранного липидного переноса.

  2. Alekseeva A., Kapkaeva M., Shcheglovitova O., Boldyrev I., Pazynina G., Bovin N., Vodovozova E. (2015). Interactions of antitumour Sialyl Lewis X liposomes with vascular endothelial cells. Biochim. Biophys. Acta 1848 (5), 1099–1110 [+]

    Recently, we showed that tetrasaccharide selectin ligand SiaLe(X) provided targeted delivery of liposomes loaded in the bilayer with melphalan lipophilic prodrug to tumour endothelium followed by severe injury of tumour vessels in a Lewis lung carcinoma model. Here, we study the impact of SiaLe(X) ligand on the interactions of liposomes with human umbilical vein endothelial cells (HUVEC) using flow cytometry, spectrofluorimetry and confocal microscopy. Liposomes composed of egg phosphatidylcholine/yeast phosphatidylinositol/1,2-dioleoyl glycerol ester of melphalan, 8:1:1, by mol, and varying percentages of lipophilic SiaLe(X) conjugate were labelled with BODIPY-phosphatidylcholine. The increase in SiaLe(X) content in liposomes led to a proportional increase in their uptake by cytokine-activated cells as opposed to non-activated HUVEC: for 10% SiaLe(X) liposomes, binding avidity and overall accumulation increased 14- and 6-fold, respectively. The early stages of intracellular traffic of targeted liposomes in the activated cells were monitored by co-localisation with the trackers of organelles. Endocytosis of SiaLe(X) liposomes occurred mostly via clathrin-independent pathways, which does not contradict the available literature data on E-selectin localisation in the plasma membrane. Using dual fluorescence labelling, with rhodamine-labelled phospholipid and calcein encapsulated at self-quenching concentrations, we found that SiaLe(X) liposomes undergo rapid (within minutes) internalisation by activated HUVEC accompanied by the disruption of liposomes; non-activated cells consumed a negligible dose of liposomes during at least 1.5h. Our data evidence the selective effect of SiaLe(X) formulations on activated endothelial cells and indicate their potential for intracellular delivery of melphalan lipophilic prodrug.

  3. Malakhov M.V., Dubinnyi M.A., Vlasova N.V., Zgoda V.G., Efremov R.G., Boldyrev I.A. (2014). End-group differentiating ozonolysis of furocoumarins. RSC Advances 4 (106), 61277–61280 [+]

    Ozonolysis of furocoumarins followed by reductive work-up yields not only common symmetrical dialdehydes, but also o-formylumbelliferones with moderate-to-high yields. Simultaneous formation of both products accounts for the transformation of carbonyl oxides – products of primary ozonide ring opening.

  4. Alekseeva A.S., Korotaeva A.A., Samoilova E.V., Volynsky P.E., Vodovozova E.L., Boldyrev I.A. (2014). Secretory phospholipase A2 activity in blood serum: The challenge to sense. Biochem. Biophys. Res. Commun. 454 (1), 178–182 [+]

    Excess levels of secretory phospholipase A2 (sPLA2) is known to contribute to several inflammatory diseases including vascular inflammation correlating with coronary events in coronary artery disease. Thus a method to monitor sPLA2 activity in blood serum is urgently needed. Such method is still a challenge since existing fluorescent probes do not allow to monitor sPLA2 activity directly in blood serum. Here we analyze and overcome barriers in sPLA2 sensing methodology and report a fluorescent probe and a kinetic model of its hydrolysis by sPLA2. New probe is designed with a fluorophore and a quencher not interfering binding to the enzyme. At the same time phospholipid matrix bearing the probe promotes efficient initial quenching of the fluorophore. Kinetic model of probe hydrolysis takes into account signal change due to the side processes. The probe and the kinetic model applied together prove the concept that the activity of sPLA can be measured directly in blood serum.

  5. Sachl R., Amaro M., Aydogan G., Koukalová A., Mikhalyov I.I., Boldyrev I.A., Humpolíčková J., Hof M. (2014). On multivalent receptor activity of GM1 in cholesterol containing membranes. Biochim. Biophys. Acta , [+]

    Gangliosides located at the outer leaflet of plasma membrane are molecules that either participate in recognizing of exogenous ligand molecules or exhibit their own receptor activity, which are both essential phenomena for cell communication and signaling as well as for virus and toxin entry. Regulatory mechanisms of lipid-mediated recognition are primarily subjected to the physical status of the membrane in close vicinity of the receptor. Concerning the multivalent receptor activity of the ganglioside GM1, several regulatory strategies dealing with GM1 clustering and cholesterol involvement have been proposed. So far however, merely the isolated issues were addressed and no interplay between them investigated. In this work, several advanced fluorescence techniques such as Z-scan fluorescence correlation spectroscopy, Förster resonance energy transfer combined with Monte Carlo simulations, and a newly developed fluorescence antibunching assay were employed to give a more complex portrait of clustering and cholesterol involvement in multivalent ligand recognition of GM1. Our results indicate that membrane properties have an impact on a fraction of GM1 molecules that is not available for the ligand binding. While at low GM1 densities (~1 %) it is the cholesterol that turns GM1 headgroups invisible, at higher GM1 level (~4 %) it is purely the local density of GM1 molecules that inhibits the recognition. At medium GM1 content, cooperation of the two phenomena occurs. This article is part of a Special Issue entitled: Nanoscale membrane orgainisation and signalling.

  6. Kuznetsova N.R., Stepanova E.V., Peretolchina N.M., Khochenkov D.A., Boldyrev I.A., Bovin N.V., Vodovozova E.L. (2014). Targeting liposomes loaded with melphalan prodrug to tumour vasculature via the Sialyl Lewis X selectin ligand. J Drug Target 22 (3), 242–250 [+]

    Earlier we showed that liposome formulation of DL-melphalan lipophilic prodrug bearing tetrasaccharide Sialyl Lewis X (SiaLe(X)) caused prolonged therapeutic effect on mammary cancer in mice. Here, we compare antivascular effect of SiaLe(X)-liposomes loaded with diglyceride ester of melphalan (Mlph) against SiaLe(X)-free formulation in Lewis lung carcinoma model. Methods: Liposomes of egg phosphatidylcholine/yeast phosphatidylinositol/1,2-dioleoyl glycerol (DOG) conjugate of Mlph/±SiaLe(X)-PEG8-15-DOG, 8:1:1:0.2 by mol, were prepared by standard extrusion. After two intravenous injections with Mlph or liposomes under either standard or delayed treatment protocols, vascular-disrupting effects of the preparations were evaluated basing on tumour section histomorphology, lectin perfusion assay and immunohistochemistry (anti-CD31 staining) data. Also, untreated mice were administered with fluorescently-labelled liposomes to assess their distribution in tumour sections with confocal laser scanning microscopy. Results: Two injections of SiaLe(X)-liposomes reproducibly caused severe injuries of tumour vessels. SiaLe(X)-liposomes co-localized with CD31 marker on vascular endothelium while the non-targeted formulation extravasated into tumour. Discussion: Cytotoxic SiaLe(X)-liposomes exhibit superior vascular-disrupting properties compared to non-targeted liposomes, yet the effect starts to transform into gain in tumour growth inhibition only under delayed treatment regimen. Conclusion: SiaLe(X)-ligand provides targeting of cytotoxic liposomes to tumour endothelium and subsequent antivascular effect.

  7. Zhai X., Boldyrev I.A., Mizuno N.K., Momsen M.M., Molotkovsky J.G., Brockman H.L., Brown R.E. (2014). Nanoscale Packing Differences in Sphingomyelin and Phosphatidylcholine Revealed by BODIPY Fluorescence in Monolayers: Physiological Implications. Langmuir 30 (11), 3154–64 [+]

    Phosphatidycholines (PC) with two saturated acyl chains (e.g., dipalmitoyl) mimic natural sphingomyelin (SM) by promoting raft formation in model membranes. However, sphingoid-based lipids, such as SM, rather than saturated-chain PCs have been implicated as key components of lipid rafts in biomembranes. These observations raise questions about the physical packing properties of the phase states that can be formed by these two major plasma membrane lipids with identical phosphocholine headgroups. To investigate, we developed a monolayer platform capable of monitoring changes in surface fluorescence by acquiring multiple spectra during measurement of a lipid force-area isotherm. We relied on the concentration-dependent emission changes of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-labeled PC to detect nanoscale alterations in lipid packing and phase state induced by monolayer lateral compression. The BODIPY-PC probe contained an indacene ring with four symmetrically located methyl (Me) substituents to enhance localization to the lipid hydrocarbon region. Surface fluorescence spectra indicated changes in miscibility even when force-area isotherms showed no deviation from ideal mixing behavior in the surface pressure versus cross-sectional molecular area response. We detected slightly better mixing of Me4-BODIPY-8-PC with the fluid-like, liquid expanded phase of 1-palmitoyl-2-oleoyl-PC compared to N-oleoyl-SM. Remarkably, in the gel-like, liquid condensed phase, Me4-BODIPY-8-PC mixed better with N-palmitoyl-SM than dipalmitoyl-PC, suggesting naturally abundant SMs with saturated acyl chains form gel-like lipid phase(s) with enhanced ability to accommodate deeply embedded components compared to dipalmitoyl-PC gel phase. The findings reveal a fundamental difference in the lateral packing properties of SM and PC that occurs even when their acyl chains match.

  8. Chugunov A.O., Volynsky P.E., Krylov N.A., Boldyrev I.A., Efremov R.G. (2014). Liquid but Durable: Molecular Dynamics Simulations Explain the Unique Properties of Archaeal-Like Membranes. Sci Rep 4, 7462 [+]

    Archaeal plasma membranes appear to be extremely durable and almost impermeable to water and ions, in contrast to the membranes of Bacteria and Eucaryota. Additionally, they remain liquid within a temperature range of 0-100°C. These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature. In this work, we use molecular dynamics simulations to assess at the atomistic level the structure and dynamics of a series of model archaeal membranes with lipids that have tetraether chemical nature and "branched" hydrophobic tails. We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells. This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems.

  9. Ivanova E.A., Maslov M.A., Kabilova T.O., Puchkov P.A., Alekseeva A.S., Boldyrev I.A., Vlassov V.V., Serebrennikova G.A., Morozova N.G., Zenkova M.A. (2013). Structure-transfection activity relationships in a series of novel cationic lipids with heterocyclic head-groups. Org. Biomol. Chem. 11, 7164–7178 [+]

    Cationic liposomes are promising candidates for the delivery of various therapeutic nucleic acids. Here, we report a convenient synthesis of carbamate-type cationic lipids with various hydrophobic domains (tetradecanol, dialkylglycerol, cholesterol) and positively charged head-groups (pyridinium, N-methylimidazolium, N-methylmorpholinium) and data on the structure-transfection activity relationships. It was found that single-chain lipids possess high surface activity, which correlates with high cytotoxicity due to their ability to disrupt the cellular membrane by combined hydrophobic and electrostatic interactions. Liposomes containing these lipids also display high cytotoxicity with respect to all cell lines. Irrespective of chemical structures, all cationic lipids form liposomes with similar sizes and surface potentials. The characteristics of complexes composed of cationic liposomes and nucleic acids depend mostly on the type of nucleic acid and P/N ratios. In the case of oligodeoxyribonucleotide delivery, the transfection activity depends on the type of cationic head-group regardless of the type of hydrophobic domain: all types of cationic liposomes mediate efficient oligonucleotide transfer into 80-90% of the eukaryotic cells, and liposomes based on lipids with N-methylmorpholinium cationic head-group display the highest transfection activity. In the case of plasmid DNA and siRNA, the type of hydrophobic domain determines the transfection activity: liposomes composed of cholesterol-based lipids were the most efficient in DNA transfer, while liposomes containing glycerol-based lipids exhibited reasonable activity in siRNA delivery under serum-free conditions.

  10. Zhai X., Momsen W.E., Malakhov D.A., Boldyrev I.A., Momsen M.M., Molotkovsky J.G., Brockman H.L., Brown R.E. (2013). GLTP-fold interaction with planar phosphatidylcholine surfaces is synergistically stimulated by phosphatidic acid and phosphatidylethanolamine. J. Lipid Res. 54 (4), 1103–13 [+]

    Among amphitropic proteins, human glycolipid transfer protein (GLTP) forms a structurally-unique fold that translocates on/off membranes to specifically transfer glycolipids. Phosphatidylcholine (PC) bilayers with curvature-induced packing stress stimulate much faster glycolipid intervesicular transfer than nonstressed PC bilayers raising questions about planar cytosol-facing biomembranes being viable sites for GLTP interaction. Herein, GLTP-mediated desorption kinetics of fluorescent glycolipid (tetramethyl-boron dipyrromethene (BODIPY)-label) from lipid monolayers are assessed using a novel microfluidics-based surface balance that monitors lipid lateral packing while simultaneously acquiring surface fluorescence data. At biomembrane-like packing (30-35 mN/m), GLTP uptake of BODIPY-glycolipid from POPC monolayers was nearly nonexistent but could be induced by reducing surface pressure to mirror packing in curvature-stressed bilayers. In contrast, 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) matrices supported robust BODIPY-glycolipid uptake by GLTP at both high and low surface pressures. Unexpectedly, negatively-charged cytosol-facing lipids, i.e., phosphatidic acid and phosphatidylserine, also supported BODIPY-glycolipid uptake by GLTP at high surface pressure. Remarkably, including both 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (5 mol%) and POPE (15 mol%) in POPC synergistically activated GLTP at high surface pressure. Our study shows that matrix lipid headgroup composition, rather than molecular packing per se, is a key regulator of GLTP-fold function while demonstrating the novel capabilities of the microfluidics-based film balance for investigating protein-membrane interfacial interactions.

  11. Semenova A.A., Chugunov A.O., Dubovskii P.V., Chupin V.V., Volynsky P.E., Boldyrev I.A. (2011). The role of chain rigidity in lipid self-association: Comparative study of dihexanoyl- and disorbyl-phosphatidylcholines. Chem. Phys. Lipids 165, 382–386 [+]

    In the course of structure-function investigations of lipids a phosphatidylcholine molecule with short and rigid tails, di-2,4-hexadienoylphosphatidylcholine (DiSorbPC), was synthesized and studied in comparison with its saturated analog, dihexanoylphosphatidylcholine (DHPC). Conjugated double bonds in the acyl chains in DiSorbPC reduce considerably the number of possible conformers of the lipid within an aggregate. This leads to impaired packing of unsaturated acyl chains and thus, to a surprisingly high (115Å(2)) area per molecule for DiSorbPC at the air-water interface and failure to form micelles of regular size and shape. Details on DiSorbPC aggregation and packing provided by a set of experimental techniques combined with molecular dynamics simulations are presented.

  12. Alekseeva A.S., Maslov M.A., Antipova N.V., Boldyrev I.A. (2011). Comparison of two lipid/DNA complexes of equal composition and different morphology. Colloids Surf B Biointerfaces 88 (1), 512–6 [+]

    Two types of complexes were prepared from a cationic cholesterol derivative, dioleoylphos-phatidylcholine and DNA. Depending on the preparation procedure complexes were either dense snarls of lipid covered DNA (type A) or multilayer liposomes with DNA between layers (type B). The transfection efficiency of the snarl-shaped complexes was low but positive. The transfection efficiency of the liposome-shaped complexes was zero, while DNA release upon their interaction with anionic liposomes was 1.7 times higher. The differences in transfection efficacy and DNA release could not be ascribed to the difference in resistance of complexes to decomposition upon interaction with anionic liposomes or intracellular environment since the lipid composition of complexes is the same. Instead the complexes in which lipoplex phase is more continuous (type A) should require more anionic lipids or more time within a cell for complete decomposition. Prolonged life time should lead to the higher probability of DNA expression.

  13. Konshina A.G., Boldyrev I.A., Utkin Y.N., Omelkov A.V., Efremov R.G. (2011). Snake cytotoxins bind to membranes via interactions with phosphatidylserine head groups of lipids. PLoS ONE 6 (4), e19064 [+]

    The major representatives of Elapidae snake venom, cytotoxins (CTs), share similar three-fingered fold and exert diverse range of biological activities against various cell types. CT-induced cell death starts from the membrane recognition process, whose molecular details remain unclear. It is known, however, that the presence of anionic lipids in cell membranes is one of the important factors determining CT-membrane binding. In this work, we therefore investigated specific interactions between one of the most abundant of such lipids, phosphatidylserine (PS), and CT 4 of Naja kaouthia using a combined, experimental and modeling, approach. It was shown that incorporation of PS into zwitterionic liposomes greatly increased the membrane-damaging activity of CT 4 measured by the release of the liposome-entrapped calcein fluorescent dye. The CT-induced leakage rate depends on the PS concentration with a maximum at approximately 20% PS. Interestingly, the effects observed for PS were much more pronounced than those measured for another anionic lipid, sulfatide. To delineate the potential PS binding sites on CT 4 and estimate their relative affinities, a series of computer simulations was performed for the systems containing the head group of PS and different spatial models of CT 4 in aqueous solution and in an implicit membrane. This was done using an original hybrid computational protocol implementing docking, Monte Carlo and molecular dynamics simulations. As a result, at least three putative PS-binding sites with different affinities to PS molecule were delineated. Being located in different parts of the CT molecule, these anion-binding sites can potentially facilitate and modulate the multi-step process of the toxin insertion into lipid bilayers. This feature together with the diverse binding affinities of the sites to a wide variety of anionic targets on the membrane surface appears to be functionally meaningful and may adjust CT action against different types of cells.

  14. Ситников Н.С., Болдырев И.А., Моисеева Е.В., Шавырин А.С., Белецкая И.П., Комб С., Бовин Н.В., Федоров А.Ю., Водовозова Е.Л. (2010). Противоопухолевые липосомы с пролекарством комбретастатина А-4 и тетрасахаридным лигандом селектинов. Известия Академии наук. Серия Химическая. 59 (12), 2234 [+]

    Получены терапевтические липосомы со средним диаметром 100 нм на основе природных фосфолипидов (фосфатидилхолина и фосфатидилинозита), содержащие пальмитоильное или олеоильное производные антимитотического агента комбретастатина А4. Цитотоксическая активность липосом с олеоильным производным в культуре клеток рака молочной железы человека оказалась лишь в 3 раза меньше, чем у комбретастатина А4, что может свидетельствовать о быстром внутриклеточном гидролизе пролекарства. С целью достижения адресной доставки в опухоли in vivo в липосомы также включали диглицеридный конъюгат тетрасахаридного лиганда селектинов — сиалил-Льюис Х (SiaLeX, 2 мол.%). На модели спонтанного рака молочной железы мышей показано достоверное ингибирование роста опухолей SiaLeXлипосомами, нагруженными липофильным пролекарством.

  15. Konshina A.G., Boldyrev I.A., Omelkov A.V., Utkin Y.N., Efremov R.G. (2010). Anionic lipids: determinants of binding cytotoxins from snake venom on the surface of cell membranes. Acta Naturae 2 (2), 88–96 [+]

    The cytotoxic properties of cytotoxins (CTs) from snake venom are mediated by their interaction with the cell membrane. The hydrophobic pattern containing the tips of loops I-III and flanked by polar residues is known to be a membrane-binding motif of CTs. However, this is not enough to explain the difference in activity among various CTs which are similar in sequence and in 3D structure. The mechanism of further CT-membrane interaction leading to pore formation and cell death still remains unknown. Published experimental data on the specific interaction between CT and low molecular weight anionic components (sulphatide) of the bilayer point to the existence of corresponding ligand binding sites on the surface of toxin molecules. In this work we study the membrane-lytic properties of CT I, CT II (Naja oxiana), and Ct 4 (Naja kaouthia), which belong to different structural and functional types (P- and S-type) of CTs, by measuring the intensity of a fluorescent dye, calcein released from liposomes containing a phosphatidylserine (PS) lipid as an anionic component. Using molecular docking simulations, we find and characterize three sites in CT molecules that can potentially bind the PS polar head. Based on the data obtained, we suggest a hypothesis that CTs can specifically interact with one or more of the anionic lipids (in particular, with PS) contained in the membrane, thus facilitating the interaction between CTs and the lipid bilayer of a cell membrane.

  16. Boldyrev I.A., Molotkovskiĭ J.G. (2010). New 4,4-Difluoro-3a,4a-Diaza-s-Indacene (BODIPY)-Labeled Sphingolipids for Membrane Studies. Russ. J. Bioorgan. Chem. 36 (4), 508–511 [+]

    The synthesis of a series of new fluorescently labeled sphingolipids containing a 4,4-difluoro-
    1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene-8-yl (Me4-BODIPY-8) group at the ω-position of a
    fatty acyl residue is described. The obtained probes were used in studies of biological and model membrane

  17. Sachl R., Boldyrev I., Johansson L.B.A. (2010). Localisation of BODIPY-labelled phosphatidylcholines in lipid bilayers. Phys. Chem. Chem. Phys. 12, 6027–6034 [+]

    A series of sn-2 acyl-labelled phosphatidyl-cholines (PC), bearing 4,4-difluoro-1-3-5-7-tetra-methyl-4-bora-3a,4a-diaza-s-indacene-8-yl (Me4-BODIPY) at the end of the Cn-acyl chains were solubilised in unilamellar vesicles and studied with respect to the order and location of the Me4-BODIPY (denoted: B) group. The obtained results are based on time-resolved electronic energy transfer from donors (2-(9-anthroyloxy)-stearic acid) localised in the lipid–water interface to acceptors BnPC (n = 3, 5, 7, 9, 11, 13, 15), as well as the energy migration among the Me4-BODIPY groups of BnPC:s. The donor–acceptor and the donor–donor experiments strongly suggest that the Me4-BODIPY group in BnPC tends to loop back close to the lipid–water interface. The Me4-BODIPY groups, residing in the two bilayer leaflets, are located at approximately the same depth, and transversally separated by ca. 27 Å for all n-values. Close to the interface, the optimal transversal distribution widens somewhat with increasing length of the sn-2 acyl chain. The obtained order parameter profile of the BnPC:s is also compatible with such a location.

  18. Sugár I.P., Zhai X., Boldyrev I.A., Molotkovsky J.G., Brockman H.L., Brown R.E. (2010). Characterization of the lateral distribution of fluorescent lipid in binary-constituent lipid monolayers by principal component analysis. Int J Biomed Imaging 2010, 125850 [+]

    Lipid lateral organization in binary-constituent monolayers consisting of fluorescent and nonfluorescent lipids has been investigated by acquiring multiple emission spectra during measurement of each force-area isotherm. The emission spectra reflect BODIPY-labeled lipid surface concentration and lateral mixing with different nonfluorescent lipid species. Using principal component analysis (PCA) each spectrum could be approximated as the linear combination of only two principal vectors. One point on a plane could be associated with each spectrum, where the coordinates of the point are the coefficients of the linear combination. Points belonging to the same lipid constituents and experimental conditions form a curve on the plane, where each point belongs to a different mole fraction. The location and shape of the curve reflects the lateral organization of the fluorescent lipid mixed with a specific nonfluorescent lipid. The method provides massive data compression that preserves and emphasizes key information pertaining to lipid distribution in different lipid monolayer phases. Collectively, the capacity of PCA for handling large spectral data sets, the nanoscale resolution afforded by the fluorescence signal, and the inherent versatility of monolayers for characterization of lipid lateral interactions enable significantly enhanced resolution of lipid lateral organizational changes induced by different lipid compositions.

  19. Akimov S.A., Hlaponin E.A., Bashkirov P.V., Boldyrev I.A., Mikhalyov I.I., Telford W.G., Molotkovskaya I.M. (2009). Ganglioside GM1 increases line tension at raft boundary in model membranes. Biochemistry (Moscow) Supplement Series A: Membrane and Cell Biology 3 (2), 216–222 [+]

    Gangliosides are significant participants in suppression of immune system during tumor processes. It was shown that they can induce apoptosis of T-lymphocytes in a raft-dependent manner. Fluorescence confocal microscopy was used to study distribution and influence of ganglioside GM1 on raft properties in giant unilamellar vesicles. Both raft and non-raft phase markers were utilized. No visible phase separation was observed without GM1 unless lateral tension was applied to the membrane. At 2 mol % of GM1 large domains appeared indicating macroscopic phase separation. Increase of GM1 content to 5 mol % resulted in shape transformation of the domains consistent with growth of line tension at the domain boundary. At 10 mol % of GM1 almost all domains were pinched out from vesicles, forming their own homogeneous liposomes. Estimations showed that the change of the GM1 content from 2 to 5–10 mol % resulted in a several-fold increase of line tension. This finding provides a possible mechanism of apoptosis induction by GM1. Incorporation of GM1 into a membrane leads to an increase of the line tension. This results in a growth of the average size of rafts due to coalescence or merger of small domains. Thus, necessary proteins can find themselves in one common raft and start the corresponding cascade of reactions.

  20. Boldyrev I.A., Gaenko G.P., Moiseeva E.V., Deligeorgiev T., Kaloianova S., Lesev N., Vasilev A., Molotkovskiĭ Iu.G. (2009). [1,10-phenantroline europium complexes: their inclusion in liposomes and cytotoxicity]. Bioorg. Khim. 37 (3), 408–13 [+]

    For a series of 1,10-phenantroline tris-beta-diketonate europium complexes (EuC), cytotoxic activity on the HBL-100 human breast carcinoma cells was determined. Liposomal preparation of the most active EuC, V12, was also tested for cytotoxicity. Testing of this preparation in vivo on starting lethal murine model of T cell leukemic lymphoma ASF-LL showed that the inclusion of V12 in liposomes did not increase its antitumour activity in a local mode of administration.

  21. Boldyrev I.A., Pavlova Iu.B., Molotkovskiĭ Iu.G. (2009). Synthesis and characteristics of new fluorescent probes based on cardiolipin. Bioorg. Khim. 35 (2), 239–44 [+]

    New fluorescent lipid probes, cardiolipin derivatives AV12-CL and B7-CL, bearing the residues of 12-(9-anthryl)-11E-dodecenoic and 7-(4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl)heptanoic acid, respectively, have been synthesized by acylation of 1-lysocardiolipin, which had been obtained from bovine heart cardiolipin by enzymatic hydrolysis with bacterial lipase. The resulting probes are intended for the study of protein-anionic phospholipid interactions.

  22. Omelkov A.V., Pavlova Iu.B., Boldyrev I.A., Molotkovskiĭ Iu.G. (2009). Depth-dependent investigation of the apolar zone of lipid membranes using a series of fluorescent probes, Me4-BODIPY-8-labeled phosphatidylcholines. Bioorg. Khim. 33 (5), 544–9 [+]

    A series of lipid probes, phosphatidylcholines labeled with Me4-BODIPY-8 (4,4-difluoro-1,3,5,7- tetramethyl-4-bora-3a,4a-diaza-s-indacen-8-yl) fluorophore attached to the end of an acyl residue at different distances from the polar head, were used as depth-dependent probes for the apolar zone of model membrane systems, large unilamellar vesicles (LUVs). Data on the anisotropy of probe fluorescence demonstrated different mobility profiles for the fluorophore microenvironment in LUVs of different composition at various temperatures, which indicates a high sensitivity of these probes as tools for studying membrane systems. An interesting anomaly was observed for LUVs from dimiristoylphosphatidylcholine (DMPC) or from a DMPC-cholesterol mixture: the anisotropy of the fluorophore located near the bilayer center is larger than that of the fluorophore located further from the center; i.e., the mobility of the microenvironment is lower in the first case. This anomaly is supposed to result from the penetration of the unlabeled long chain of the probes into the opposite bilayer leaflet. Such a possibility should be taken into account in constructing fluorescent probes and interpreting the results.

  23. 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.

  24. Boldyrev I.A., Molotkovskiĭ I.G. (2006). [A synthesis and properties of new 4,4-difluoro-3a,4a-diaza-s-indacene (BODIPY))-labeled lipids]. Bioorg. Khim. 32 (1), 87–92 [+]

    A series of fluorescently labeled fatty acids of various chain lengths with 4,4-difluoro-1,3,5,7-tetramethyl-4-bora-3a,4a-diaza-s-indacene-8-yl (Me4-BODIPY-8) residue in the omega-position were synthesized. These acids were used to prepare new fluorescently labeled phosphatidylcholines, sphingomyelin, and galactosyl ceramide. Taking into account the symmetry of the Me4-BODIPY-8-fluorophore, one can presume that, in most bilayer membrane systems, this fluorophore is would be embedded into the bilayer.

  25. Boldyrev I.A., Molotkovskiĭ Yu.G. (2005). A synthesis of new rigid fluorescent bichromophoric probes for studying mechanisms of donor-donor energy migration. Bioorg. Khim. 31 (3), 331–4 [+]

    Three new fluorescent probes were synthesized for improving the method of studying donor-donor energy migration (DDEM). Each probe has two identical fluorescent 7-diethylaminocoumarin-3-carbonyl groups attached to a rigid bisteroid dodecacyclic spacer through additional inserts. In two probes, the inserts are beta-Ala and L-Ser residues, which provide for a different nearest environment of the fluorophores. The third probe has identical beta-Ala inserts. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.

  26. Boldyrev I.A., Molotkovskiĭ Yu.G. (2004). Fluorescent properties of 9-anthracenecarboxamides. Bioorg. Khim. 30 (6), 649–55 [+]

    A number of new 9-anthracenecarboxamides are synthesized in order to create new fluorescent probes for studying biological systems. The parameters of their fluorescence in organic solvents of various polarities are investigated, and possible mechanisms of internal quenching of fluorescence of these compounds are discussed. One of the compounds, 4-ethoxycarbonylphenylamide of 9-anthracenecarboxylic acid, is shown to be a promising basis for the development of a new fluorescent probe. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 6; see also http://www.maik.ru.

  27. Boldyrev I.A., Grechishnikova I.V., Pavlova Iu.B., Molotkovskiĭ Iu.G. (2004). Synthesis and properties of fluorescently-labelled triglyceride, derivative of the antineoplastic agent sarcolysin. Bioorg. Khim. 30 (1), 80–3 [+]

    A new fluorescent probe, a 3-perylenoyl derivative of the lipophilized antitumor drug merphalan (sarcolysine), was synthesized. The probe is suitable for studying intracellular traffic and metabolism of merphalan and its derivatives. The perylenoyl fluorescence is partially quenched by the merphalan chromophore, which broadens the probe potentialities. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 1; see also http://www.maik.ru.