Papers by Yegor E Yegorov
Biochemistry (Moscow), Oct 31, 2023
The science of telomeres and telomerase has made tremendous progress in recent decades. In this r... more The science of telomeres and telomerase has made tremendous progress in recent decades. In this review, we consider it first in a historical context (the Carrel-Hayf lick-Olovnikov-Blackburn chain of discoveries) and then review current knowledge on the telomere structure and dynamics in norm and pathology. Central to the review are consequences of the telomere shortening, including telomere position effects, DNA damage signaling, and increased genetic instability. Cell senescence and role of telomere length in its development are discussed separately. Therapeutic aspects and risks of telomere lengthening methods including use of telomerase and other approaches are also discussed.
Russian Journal of Developmental Biology, 2011
53 The award of the Demidov prize to A.M. Olovnikov is an important event generally for our nativ... more 53 The award of the Demidov prize to A.M. Olovnikov is an important event generally for our native biological science and, in particular, for the Russian Journal of Developmental Biology. The significance of this event to science in Russia is that the work of A.M. Olovnikov is widely recognized by the world scientific community. Also, the significance to our journal is that for many years he has been a mem ber of the editorial board and his active work has led to the success of the journal. The originality of the event being discussed is linked to the fact that, to some extent, it has been a “Russian response” to the award of the Nobel Prize to the group of American scientists for advancement in the research of telomeres and telomerase. This decision by the Nobel committee has been widely discussed in scientific and nonscientific circles in Russia. Many scientists were perplexed that Olovni kov was not among the recipients of this most presti gious award. In nonscientific and near scientific cir cles, this issue was jokingly discussed but was not always in a friendly way. Discussing the motive and basis of the Nobel com mittee decision is unlikely to make sense although we would return to this question again. There is the need to consider the essence of the work of Olovnikov. According to the decision of the Demidov commit tee, Olovnikov was awarded the prize for a series of the oretical works in which the shortening of chromosomes during aging was predicted and the effect of the end underreplication of the linear DNA molecule, as well the existence of telomerase as an enzyme which com pensates for the telomere shortening (end regions of chromosomes), was described. Looking retrospectively at when these researches were carried out, undoubtedly two people whose contri butions were obviously underestimated by the world sci entific society can be distinguished. They are Leonard Hayflick and Alexey Olovnikov. The work of Hayflick (Hayflick and Moorhead, 1961) is still one of the most cited in biology. It did not only identify the then before unknown fact but awak ened the creative energy of most scientists in their attempt to explain how cells count their division. As a result of many years research Hayflick showed that human cells divide in culture only a finite number of times after which they initially stop dividing and later die. Hayflick published his results with great difficulty. Presenting the history of his discovery at the Telomeres and Telomerase: Implications of Cell Immortality, Cancer, and Related Diseases Conference (Redwood City, California, June 1–3, 1998), Hayflick stated that when his paper went for review by the later to be Nobel Prize winner, Peyton Rous (discoverer of Rous sar coma) rejected it. The public opinion by then was dom inated by the belief that, in the hands of a skillful researcher, cells are immortal, i.e., the number of divi sions is infinite. This was based on the indisputable authority of Nobel Prize winner Alexis Carrel, who, in the early twentieth century, convinced a large mass of researchers that cells can be cultured for decades (Car rel, 1912).
PubMed, Aug 1, 1999
The reverse transcriptase inhibitors (RTI) azidothymidine and carbovir can block telomerase funct... more The reverse transcriptase inhibitors (RTI) azidothymidine and carbovir can block telomerase function in various cells, whereas dideoxycytidine does not exhibit such activity. RTI induce senescence in 3T3 Swiss, NIH 3T3 cell cultures and in the clones of immortal spontaneously transformed mouse fibroblasts. The RTI-induced senescence of L6 rat myoblasts in culture resembles the senescence of fibroblasts, but the resulting cells acquire sharp morphological peculiarities. The artificial senescence of fibroblasts and myoblasts resulted in both the appearance of corresponding senescent cells and a small portion of cells with the signs of another type of differentiation. The blockade of telomerase function by RTI in the human tumour cell lines U-937 and MeWo leads to the shortening of telomeres, but does not result in senescence. These cells may undergo crisis and after a while the proliferation resumes and resistant cells appear. RTI inhibit spontaneous reactivation of telomerase in the process of spontaneous transformation of mouse embryonic fibroblasts, which leads to the formation of telomerase-free clones. A fraction of these clones may overcome the senescence via the acquisition of telomerase activity. Cells with a very high level of telomerase activity become resistant to RTI. Thus, the blockade of telomerase function in different cells can induce senescence, partial differentiation or crisis. In human tumour cells it induces mainly crisis.
American Journal of Therapeutics, 2016
The aging eye appears to be at considerable risk from oxidative stress. A great deal of research ... more The aging eye appears to be at considerable risk from oxidative stress. A great deal of research indicates that dysfunctional mitochondria are the primary site of reactive oxygen species (ROS). More than 95% of O 2 2Á produced during normal metabolism is generated by the electron transport chain in the inner mitochondrial membrane. Mitochondria are also the major target of ROS. Cataract formation, the opacification of the eye lens, is one of the leading causes of human blindness worldwide, accounting for 47.8% of all causes of blindness. Cataracts result from the deposition of aggregated proteins in the eye lens and lens fiber cell plasma membrane damage, which causes clouding of the lens, light scattering, and obstruction of vision. ROS-induced damage in the lens cell may consist of oxidation of proteins, DNA damage, and/or lipid peroxidation, all of which have been implicated in cataractogenesis. This article is an attempt to integrate how mitochondrial ROS are altered in the aging eye along with those protective and repair therapeutic systems believed to regulate ROS levels in ocular tissues and how damage to these systems contributes to age-onset eye disease and cataract formation. Mitochondriatargeted antioxidants might be used to effectively prevent ROS-induced oxidation of lipids and proteins in the inner mitochondrial membrane in vivo. As a result of the combination of weak metal chelating, OH_ and lipid peroxyl radicals scavenging, reducing activities to liberated fatty acid, and phospholipid hydroperoxides, carnosine and carcinine appear to be physiological antioxidants able to efficiently protect the lipid phase of biologic membranes and aqueous environments and act as the antiapoptotic natural drug compounds The authors developed and patented the new ophthalmic compositions, including N-acetylcarnosine, acting as a prodrug of naturally targeted to mitochondria L-carnosine endowed with pluripotent antioxidant activities combined with mitochondria-targeted
Biochemistry (Moscow). Supplement. Series A, Membrane and cell biology, Mar 1, 2009
A cell culture of rare and threatened species of Sakhalin sturgeon Acipenser mikadoi was establis... more A cell culture of rare and threatened species of Sakhalin sturgeon Acipenser mikadoi was established from a fragment of the pectoral fin and neighboring tissues. Initially, the culture consisted of different cell types including typical fibroblasts as well as cells of epithelial origin, myofibroblasts, etc. After approximately five passages, the culture largely consisted of cells with fibroblast morphology. Under normal culture conditions, these cells grew for more than one year at a constant rate and passed about 80 population doublings. In the absence of serum, cells entered the state of proliferative quiescence (G 0-state). When cultured without medium replacement for a long period of time, cells fused to form myofibers of about 1 cm in length. These myofibers could branch and acquired cross striation with time. About forty days after myofibers emerged, they degenerated, lost their shape, detached from the substrate, and finally died. The induction of adipogenic differentiation arrested cell proliferation and introduced lipophilic inclusions formed in a minor fraction of cells. The number of these inclusions was low, and cells with inclusions demonstrated various morphology distinct from typical adipocytes. The induction of osteogenic differentiation gave rise to cells that produce mineralized extracellular matrix and bone nodules. Chromosome analysis revealed a set of chromosomes typical for "high chromosome" sturgeon species. The variation in the chromosome number was very high (mean, 247 ± 33 ; modal value, 248). The analysis involving AT-and GC-specific fluorochromes has demonstrated that the telomeric and centromeric regions of all chromosomes are enriched in GC content. The distribution of AT-and GC-rich sequences along the chromosomes was heterogeneous. Long chromosomes were preferentially stained by the AT-specific dye, whereas small chromosomes demonstrated brighter fluorescence after 7-amino-actinomycin D staining; in particular, several small chromosomes fluoresced extremely brightly. This work is the first report of cell culture and karyotype analysis of Sakhalin sturgeon.
Recent Patents on Drug Delivery & Formulation, Jun 24, 2016
Molecular Biology, Jul 1, 2021
Abstract Hydrophobic molecules may be toxic when present in excess. When dissolved in membranes, ... more Abstract Hydrophobic molecules may be toxic when present in excess. When dissolved in membranes, hydrophobic molecules disrupt membrane function. Studies on the effects of free fatty acids (FFA) on cultured cells contradict each other. Here we describe the effects of FFA on various human cells in culture. The addition of long-chain FFA (oleic, palmitic, linoleic, linolenic, etc.) to cultured cells led to lipid accumulation in hepatocytes and muscle cells, initiation of autophagy, and uncoupling of oxidative phosphorylation. Although treated cells increase their oxygen consumption, metabolic shifts in favor of glycolysis were observed. All these effects were expressed to varying degrees in different cells and with the addition of different FFAs. The mechanisms of these FFA effects are discussed, as well their practical implications.
Recent Patents on Drug Delivery & Formulation, Nov 1, 2010
A pharmacological chaperone is a relatively new concept in the treatment of certain chronic disab... more A pharmacological chaperone is a relatively new concept in the treatment of certain chronic disabling diseases. Cells maintain a complete set of functionally competent proteins normally and in the face of injury or environmental stress with the use of various mechanisms, including systems of proteins called molecular chaperones. Proteins that are denatured by any form of proteotoxic stress are cooperatively recognized by heat shock proteins (HSP) and directed for refolding or degradation. Under non-denaturing conditions HSP have important functions in cell physiology such as in transmembrane protein transport and in enabling assembly and folding of newly synthesized polypeptides. Besides cellular molecular chaperones, which are stress-induced proteins, there have been recently reported chemical, or so-called pharmacological chaperones with demonstrated ability to be effective in preventing misfolding of different disease causing proteins, specifically in the therapeutic management of sight-threatening eye diseases, essentially reducing the severity of several neurodegenerative disorders (such as age-related macular degeneration), cataract and many other protein-misfolding diseases. This work reviews the biological and therapeutic activities protected with the patents of the family of imidazole-containing peptidomimetics Carcinine (β-alanylhistamine), N-acetylcarnosine (N-acetyl-β-alanylhistidine) and Carnosine (β-alanyl-L-histidine) which are essential constituents possessing diverse biological and pharmacological chaperone properties in human tissues.
Current Molecular Medicine, Oct 1, 2011
Current Clinical Pharmacology, Apr 1, 2014
Influenza A is a viral disease of global dimension, presenting with high morbidity and mortality ... more Influenza A is a viral disease of global dimension, presenting with high morbidity and mortality in annual epidemics, and in pandemics which are of infrequent occurrence but which have very high attack rates. Influenza vaccines of the future must be directed toward use of conserved group-specific viral antigens, such as are present in transitional proteins which are exposed during the fusion of virus to the host cell. Influenza probes revealed a continuing battle for survival between host and parasite in which the host population updates the specificity of its pool of humoral immunity by contact with and response to infection with the most recent viruses which possess altered antigenic specificity in their hemagglutinin (HA) ligand. It is well known that the HA protein is found on the surface of the influenza virus particle and is responsible for binding to receptors on host cells and initiating infection. Polymorphonuclear neutrophils (PMN) have been reported to be involved in the initial host response to influenza A virus (IAV). Early after IAV infection, neutrophils infiltrate the airway probably due to release of chemokines that attract PMN. Clearly, severe IAV infection is characterized by increased neutrophil influx into the lung or upper respiratory tract. Carnosine (β-alanyl-L-histidine) and anserine (N-β-alanyl-1-methyl-L-histidine) are found in skeletal muscle of most vertebrates, including those used for food; for example, 100 g of chicken breast contains 400 mg (17.6 mmol/L) of carnosine and 1020 mg (33.6 mmol/l) of anserine. Carnosine-stimulated respiratory burst in neutrophils is a universal biological mechanism of influenza virus destruction. Our own studies revealed previously unappreciated functional effects of carnosine and related histidine containing compounds as a natural biological prevention and barrier against Influenza virus infection, expand public understanding of the antiviral properties of imidazole-containing dipeptide based compounds, and suggest important interactions between neutrophills and carnosine related compounds in the host response to viruses and bacteria. Carnosine and anserine were also found to reduce apoptosis of human neutrophils. In this way these histidine-containing compounds can modulate the Influenza virus release from neutrophills and reduce virus dissemination through the body of the organism. This review points the ability of therapeutic control of Influenza viral infections associated with modulation by oral nonhydrolized forms of carnosine and related histidine-containg compounds of PMN apoptosis which may be involved at least in part in the pathophysiology of the disease in animals and humans. The data presented in this article, overall, may have implications for global influenza surveillance and planning for pandemic influenza therapeutic prevention with oral forms of non-hydrolized natural L-carnosine as a suitable alternative to the conventional vaccination for various flu ailments.
Biomedicines, Nov 17, 2022
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Molekulârnaâ biologiâ, 2021
Hydrophobic molecules may be toxic when present in excess. When dissolved in membranes, hydrophob... more Hydrophobic molecules may be toxic when present in excess. When dissolved in membranes, hydrophobic molecules disrupt membrane function. Studies on the effects of free fatty acids (FFA) on cultured cells contradict each other. Here we describe the effects of FFA on various human cells in culture. The addition of long-chain FFA (oleic, palmitic, linoleic, linolenic, etc.) to cultured cells led to lipid accumulation in hepatocytes and muscle cells, initiation of autophagy, and uncoupling of oxidative phosphorylation. Although treated cells increase their oxygen consumption, metabolic shifts in favor of glycolysis were observed. All these effects were expressed to varying degrees in different cells and with the addition of different FFAs. The mechanisms of these FFA effects are discussed, as well their practical implications.
Russian Journal of Bioorganic Chemistry, Mar 1, 2018
⎯S-layer proteins of lactobacilli may be utilized for developing a surface display system in thes... more ⎯S-layer proteins of lactobacilli may be utilized for developing a surface display system in these bacteria. In this study, S-layer proteins of Lactobacillus brevis ATCC 367 were identified for the first time. Using the peptide fingerprint method, it was shown that the main protein of the S-layer of this strain, SlpE, having a mass of 52 kDa is the product of translation of the consecutive open reading frames LVIS_2086 and LVIS_2085. Repeated sequencing of a genome region of L. brevis ATCC 367, containing LVIS_2086 and LVIS_2085 loci, has showed that the LVIS_2086 sequence contains the TGG tryptophan codon instead of the TAG stop codon. Thus, LVIS_2085 and LVIS_2086 form a single slpE gene, the nucleotide sequence we deposited in the Genbank database under No. KY273133. The translation product of the slpE gene consists of 465 amino acids and has a calculated mass of 51.6 kDa, which corresponds to the experimentally obtained value. An S-layer protein with a mass of 56 kDa, identified as a form of the SlpE, is probably formed during the posttranslational modification. The concomitant 48 kDa S-protein was proven to be product of the LVIS-2083 gene. The N-terminal domains of LVIS_2083 and SlpE have 70.7 and 96.5%, respectively, identity to the anchoring N-terminal domain of SlpA from L. brevis ATCC 8287, which is responsible for attachment to the cell wall. In this work, fusion proteins consisting of N-terminal domains of Lvis_2083 and SlpA proteins and the eGFP marker protein were obtained. The ability of fusion proteins SlpA_eGFP and Lvis_2083_eGFP, as well as the recombinant Lvis_2083 protein, to be specifically sorbed on the cell wall of L. brevis ATCC 8287, ATCC 367, and L. acidophilus ATCC 4356 strains has been demonstrated. It was shown that in the chimeric Lvis_2083_eGFP construction the N-terminal domain Lvis_2083 is responsible for an attachment to the cell wall and provides display of the functionally active eGFP protein on its surface. Thus, the N-terminal domain Lvis_2083 can be used as a basis of the protein display system on the cell surface of L. brevis strains in vitro.
Molecular Biology, May 1, 2020
The free radical theory of aging was proposed in 1956. Although it does not fully describe the me... more The free radical theory of aging was proposed in 1956. Although it does not fully describe the mechanisms of aging, it is generally accepted that reactive oxygen species (ROS) are one of the pathogenetic factors in aging and, in particular, in the development of pathologies associated with aging. The main source of ROS in the cell is mitochondria. Antioxidants directed to mitochondria have a positive effect, but have low efficiency. The problem is that increased amounts of antioxidants disrupt normal cellular redox reactions, and a low amount of antioxidants is not able to seriously affect the processes. Protection against ROS may be more effective if the rate of ROS formation is reduced. There is a natural mitochondrial uncoupling process that significantly reduces ROS production. The weak uncoupler dinitrophenol (DNP) prolongs the life span of mice, reduces traumatic brain damage, and inhibits the development of a number of neurodegenerative diseases. Unfortunately, DNP has a number of disadvantages that hinder its practical use. Uncoupling of oxidative phosphorylation by free fatty acids is a natural mechanism, the activation of which can be used in medicine. The third (after antioxidants and uncouplers), but so far little studied, method of reducing ROS is telomerase, which, under conditions of oxidative stress, is transported into the mitochondria and improves cell survival by reducing ROS production.
Critical Reviews in Therapeutic Drug Carrier Systems, 2010
The purpose of this study was to determine how the naturally occurring molecules N-acetylcarnosin... more The purpose of this study was to determine how the naturally occurring molecules N-acetylcarnosine, L-carnosine, and carcinine, which are chemical or pharmacological chaperones, affect the cells and biomolecules of patients with skin diseases, cosmetic skin lesions, or underlying clinically significant visual impairment such as age-related cataracts, age-related retinal degeneration, and ocular complications of diabetes. We evaluated and characterized the effects of cited pharmacological chaperones on enzyme activity, protein structure in tissues, and other biomarkers of diseases in skin cells and tissues or in ocular tissues (human cataractous and normal lenses) derived from ophthalmic patients or age-matched donors. The samples were used to test imidazole-containing peptidomimetic chemical/pharmacological chaperones in relation to oxidative stress induced by reaction with lipid peroxides or advanced non-enzymatic glycation processes. Chaperone function is characterized by interaction with other proteins, mediating their folding, transport, and interaction with other molecules, lipid peroxidation products, and membranes. Although these therapies remain on hold pending further investigation, we present growing evidence demonstrating the ability of N-acetylcarnosine (lubricant eye drops) or carcinine pharmacological chaperone therapy to act as novel treatments for age-related cataracts, age-related macular degeneration, and ocular complications of diabetes. Finally, we examine strategies for identifying potential chaperone compounds and for experimentally demonstrating chaperone and transglycating (de-glycation) types of activity in in vitro and in vivo models of human age-related eye diseases, such as cataracts, and advanced glycation tissue protein-engineered systems.
Histochemistry and Cell Biology, Mar 25, 2010
The ability of dermal papilla (DP) cells to induce hair growth was reported in many studies. Howe... more The ability of dermal papilla (DP) cells to induce hair growth was reported in many studies. However, early stages of hair follicle development and signals that govern this process are poorly understood. Therefore, an in vitro model may be a convenient system to study epithelial-mesenchymal interactions and early stages of epidermal morphogenesis, especially in humans. To investigate the role of DP cells in epidermal morphogenesis we modified the method of isolation of DP cells from hair follicle of human scalp and developed the three-dimensional model of epidermal morphogenesis. Isolated DP cells were able to differentiate in adipogenic and osteogenic directions and retained activity of alkaline phosphatase (AP) for seven passages in culture. DP cells were able to induce tubule-like structures in three-dimensional model in vitro and to reorganize collagen matrix. Prolonged cultivation of DP cells has been a big problem because of the loss of hair follicle-inducing ability and growth activity after several passages. To solve this problem we immortalized DP cells by the transfection of the human telomerase reverse transcriptase cDNA (hTERT). Immortalized DP-hTERT cells retained AP activity and demonstrated low ability to osteogenic differentiation. The conditioned medium collected from actively proliferated cells as well as DP-hTERT cells themselves were capable to induce tubulogenesis after prolonged keratinocyte cultivation.
Cell Biology International, Dec 1, 2002
In previous work we demonstrated that various types of cultured cells with a limited life span co... more In previous work we demonstrated that various types of cultured cells with a limited life span could not reactivate DNA synthesis in the nuclei of mouse peritoneal macrophages in heterokaryons. We now investigate the role of telomerase in the process of the macrophage nucleus reactivation in heterokaryons with immortal telomerase-positive 3T3 Swiss mouse fibroblasts and human fibroblasts with introduced hTERT gene. We report that introduction of the hTERT gene into human diploid fibroblasts results in emergence of telomerase activity in these cells and the ability to induce the reactivation of DNA synthesis in the macrophage nuclei in heterokaryons. Inhibition of telomerase activity in heterokaryons by reverse transcriptase inhibitors (azidothymidine and guanosine polyphosphonate analogues) and by a 2-O-methyl-RNA oligonucleotide anti-sense to the template region of telomerase RNA, block reactivation of DNA synthesis in macrophage nuclei without inhibiting DNA synthesis in the nuclei of fibroblasts. Our results suggest alterations (shortening or damage) in the macrophage telomere structure. As far as we know, heterokaryons with macrophages are the first cellular model for rapid investigation of the effects of telomerase inhibitors.
Biologicheskie Membrany, Dec 1, 1998
ABSTRACT
Review includes broad spectrum of data concerning telomeres and telomerase. Along with descriptio... more Review includes broad spectrum of data concerning telomeres and telomerase. Along with description of telomere length and telomerase activity alterations in the process of development there are data about telomere and telomerase roles in the oncogenesis, the consequences of hereditary decreasing of telomerase activity, and principles of cancer treatment in the context of telomerase. Some attention paid to recent discoveries of nontelomeric functions of telomerase, the history of Nobel prize awarding in 2009 and to linkage of peripheral blood leucocytes telomere length with the development of various pathologies associated with aging. Some data are presented concerning telomere biology of stem cells and forced expression of telomerase in human cells (telomerization).
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Papers by Yegor E Yegorov