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Cognitive impairments are closely related to synaptic loss in Alzheimer’s disease (AD). Functional changes in synaptic contacts are reflected in dendritic spine morphology. Visualization of neurons for morphological studies in vivo is complicated by the fixed brain slice staining or expensive adeno-associated virus injections. We created a transgenic 5xFAD-M line of mice with AD-associated mutations and expressed GFP protein in single neurons of the brain. This mouse model of AD is a useful tool for the simplified visualization of the hippocampal neurons’ morphology in vivo without additional staining manipulations. The progressive elimination of mushroom spines was demonstrated in 5xFAD-M mice between 4 and 5 months of age. Five-month-old 5xFAD-M male and female mice showed change both in the total density and the mushroom spines number compared to sex-matched control. We conclude 5xFAD-M mice can be a useful AD model for studying the mechanisms of synaptic pathology under neurodegenerative conditions and evaluating the effects of potential therapeutic agents on spine morphology as crucial aspect of memory loss in AD.

A senescence-associated secretory phenotype (SASP) and a mild inflammatory response characteristic of senescent cells (inflammaging) form the conditions for the development of cardiovascular diseases: atherosclerosis, coronary heart disease, and myocardial infarction. The purpose of the review is to analyze the pool of signaling molecules that form SASP and inflammaging in cells of the cardiovascular system and to search for targets for the action of vasoprotective peptides. The SASP of cells of the cardiovascular system is characterized by a change in the synthesis of anti-proliferative proteins (p16, p19, p21, p38, p53), cytokines characteristic of inflammaging (IL-1α,β, IL-4, IL-6, IL-8, IL-18, TNFα, TGFβ1, NF-κB, MCP), matrix metalloproteinases, adhesion molecules, and sirtuins. It has been established that peptides are physiological regulators of body functions. Vasoprotective polypeptides (liraglutide, atrial natriuretic peptide, mimetics of relaxin, Ucn1, and adropin), KED tripeptide, and AEDR tetrapeptide regulate the synthesis of molecules involved in inflammaging and SASP-forming cells of the cardiovascular system. This indicates the prospects for the development of drugs based on peptides for the treatment of age-associated cardiovascular pathology.

Neuroprotective peptides are promising candidate molecules for the treatment of Alzheimer's disease (AD). Oral application of KED (Lys-Glu-Asp) improved memory and attention in elderly individuals with functional CNS disorders. Peptide KED also restores synaptic plasticity in in vitro model of AD. This review is focused on the analysis of the influence of KED peptide on the expression of genes and synthesis of proteins regulating apoptosis, aging, neurogenesis, and involved in AD pathogenesis. Analysis of published reports and our experimental findings suggests that KED regulates the expression of genes of cell aging and apoptosis (р16, р21), genes (NES, GAP43) and proteins (nestin, GAP43) of the neuronal differentiation, and genes involved in AD pathogenesis (SUMO, APOE, and IGF1). The study the effectiveness of neuroprotective peptide KED in animal models of AD seems to be very important.

The search for innovative ways to treat osteoarthritis (OA) is an urgent task for molecular medicine and biogerontology. OA leads to disability in persons of middle and older age, while safe and effective methods of treating OA have not yet been discovered. The directed differentiation of mesenchymal stem cells (MSCs) into chondrocytes is considered one of the possible methods to treat OA. This review describes the main molecules involved in the chondrogenic differentiation of MSCs. The peptides synthesized on the basis of growth factors’ structures (SK2.1, BMP, B2A, and SSPEPS) and components of the extracellular matrix of cartilage tissue (LPP, CFOGER, CMP, RDG, and N-cadherin mimetic peptide) offer the greatest promise for the regulation of the chondrogenic differentiation of MSCs. These peptides regulate the WNT, ERK-p38, and Smad 1/5/8 signaling pathways, gene expression, and the synthesis of chondrogenic differentiation proteins such as COL2, SOX9, ACAN, etc.

Young age is the best period of human life but it has its peculiarities and hardships. The up-to-date academic process is carrying great physical, psychophysical and emotional loads. A student faces different hardships not only during the academic process, but in everyday, social life. Such a situation may result in fatigue in chronic form - chronic fatigue syndrome, often being reflected on professional training of students. The article deals with the main risk factors of chronic fatigue in students. The sleep and diet regimens of students are examined for this purpose. Besides, dependence of chronic fatigue on motion activity and possible stress in young people’s lives is noted.

Inflamm-aging - the term, describes the development of chronic inflammation during aging without the infection pathology. It is supposed, that inflamm-aging is one of the reason of age-related pathology, partially, Alzheimer disease (AD). There were done comparative analysis of AD (Аβ42, τ-protein, р16) and inflammation (IL-6, TGFα, NF-kB) markers in hippocamp and blood lymphocytes in elderly and old people. It was shown, that expression of investigated signal molecules in hippocamp and lymphocytes of elderly and old AD people increased in comparison with people of control group (without neurodegenerative pathology). Thus, inflammation mediators play important role in AD pathogenesis and can be the potential target for neuropathology therapy.

The goal of the research is to study the effect of KE peptide on telomere length of PHA-stimulated blood lymphocytes of young and middle-aged men. 11 blood lymphocyte samples were enrolled in the analysis. Relative telomere length was measured using fluorescence in situ hybridization with DNA-probes specific to telomere sequences of human chromosomes. 5 cases of significant telomere length alteration were registered. These changes were more frequent registered in middle-aged people: 4 invents cases versus 1. KE peptide increased telomere length in blood lymphocytes of middle-aged people if it was basically low and, vice versa, decreased the basically high telomere length.

A large variety of short biologically active peptides possesses antioxidant, antibacterial, antitumour, anti-ageing and anti-inflammatory activity, involved in the regulation of neuro-immuno-endocrine system functions, cell apoptosis, proliferation and differentiation. Therefore, the mechanisms of their biological activity are attracting increasing attention not only in modern molecular biology, biochemistry and biophysics, but also in pharmacology and medicine. In this work, we systematically analysed the ability of dipeptides (all possible combinations of the 20 standard amino acids) to bind all possible combinations of tetra-nucleotides in the central part of dsDNA in the classic B-form using molecular docking and molecular dynamics. The vast majority of the dipeptides were found to be unable to bind dsDNA. However, we were able to identify 57 low-energy dipeptide complexes with peptide-dsDNA possessing high selectivity for DNA binding. The analysis of the dsDNA complexes with dipeptides with free and blocked N- and C-terminus showed that selective peptide binding to dsDNA can increase dramatically with the peptide length.

We studied the expression of ARID1A, prostaglandin E2 synthase, and prostaglandin E2 receptor in the endometrium and ovarian, peritoneal, and intestinal endometrioid heterotopies in women with endometriosis of young and middle reproductive age. ARID1A protein is a tumor suppressor, its expression reduced in different types of cancer. Prostaglandin E2 synthase and prostaglandin E2 receptor are involved in the signaling cascade of inflammatory reactions presumably underlying the development of endometriosis. In endometrioid heterotopies, expression of ARID1A was reduced in 1.2-4.0 times, the expression of prostaglandin E2 synthase and prostaglandin E2 receptor was reduced in 2.9-5.2 times These findings suggest that ARID1A, prostaglandin E2 synthase, and prostaglandin E2 receptor can be used as predictors of malignant transformation of endometrioid heterotopies in women with endometriosis.

Cardiovascular diseases caused by atherosclerosis are one of the most important social and economic problems in many countries of the world due to the high morbidity and mortality rate of the working population. An immunological theory of atherosclerosis and coronary heart disease (CHD) has been actively developed of late, and markers of inflammation characterizing immuno- and atherogenesis have been sought. The buccal epithelium (BE) can be used as biological material for in vivo molecular-cellular studies, allowing CHD diagnosis via inflammation markers. The purpose of the work was a comparative study of the expression of IL-1β, IL-6, IL-10, MCP-1, and GDF-15 in BE in patients of different ages with CHD and without cardiovascular disease. The BE material in healthy donors and patients with second-stage CHD was divided into groups according to the age classification of the WHO: the first group included middle-aged people (45–59 years), and the second included elderly people (60–74 years). Control material was obtained from people of middle and old age without cardiovascular disease. According to the immunocytochemical study, the area of IL-1β expression in BE is three times higher in middle-aged CHD patients and 4.4 times higher in elderly people as compared to healthy individuals of the same age group. The area of IL-6 expression in middle-aged and elderly CHD patients was 7.9 and 7.4 times higher, respectively, than in the control group. In middle-aged and elderly CHD patients, the IL-10 expression was 1.6 and 2.8 times higher, respectively, as compared to healthy donors of the same age group. The MCP-1 expression in the BE of middle-aged and elderly people with and without ischemic heart disease did not differ. GDF-15 expression is 6.8 and 6.6 times higher in middle-aged and elderly CHD patients than in healthy people of the same age. The findings showed that the expression of the cytokines IL-1β, IL-6, IL-10, and GDF-15 increase in the BE of patients with CHD in middle-aged and elderly people as compared with persons of the same age group without cardiovascular disease. Thus, the BE can serve as an informative material for noninvasive molecular diagnosis of CHD in people of different ages.

Cortexin is a clinically approved cerebral cortex polypeptide complex in calves. The mechanism of cortexin action is not understood well. Two cortexin derivatives, short peptides EDR and DS with neuroprotective activity, were synthesized. According to the data of molecular modeling, these peptides are able to bind to the histone H1.3 protein. This can affect the conformation of histone H1.3, which leads to a change in the chromatin structure in the loci of some genes, in particular Fkbp1b encoding the FK506-binding protein. Electrophysiological processes associated with the Ca^(2+) exchange are disturbed in the pyramidal neurons of the hippocampus during aging of the brain. The Fkbp1b gene encodes peptidyl-prolyl cis-trans isomerase, regulating the release of calcium ions from the sarcoplasmic and endoplasmic reticulum of neurons. The activation of the Fkbp1b gene transcription under treatment with short peptides can promote the synthesis of its protein product and the activation of the Ca^(2+) release from organelles of the sarcoplasmic and endoplasmic reticulum of neurons, which, in turn, can lead to an increase in the functional activity of neurons.

More than a quarter of the elderly and senile age population suffers from kidney pathology. For this reason, a prophylaxis of kidney diseases with safe and effective nephroprotectors is a priority of gerontology. This work studies the influence of the polypeptide kidney complex (PKC) and peptides AED, EDL, and AEDG, on the functional state of kidneys in old rats. The administration of the PKC and peptides AED and EDL increased diuresis by 1.2–1.4 times. The PKC and peptide AED reduced the urine protein level and protein excretion by 1.5–2.8 times. The PKC and peptides AED and EDL increased distal sodium transport by 1.2–1.3 times. The peptides AED and EDL increased sodium excretion by 1.3 and 1.6 times respectively. The renal effects of the peptide AEDG resulted in a 21% reduction of glomerular filtration rate, a 3.1-fold decrease in the urine protein level, and a 2.5-fold decrease in protein excretion. The peptide AEDG reduced absolute sodium reabsorption by 1.3 times and increased distal sodium transport by 1.4 times. The realization of glomerular–tubular and tubular–tubular balances is verified by the correlation between the glomerular filtration rate (GFR) and absolute, proximal, and distal sodium reabsorption. In kidney tissue, stimulation of the antioxidant enzyme activity on the background of inhibition of the intensity peroxidation processes was observed, which, together with morphological data, reflects the absence of nephrotoxic effects. PKC and peptides AED, EDL, and AEDG may be considered nephroprotective agents in kidney aging.

Ultrashort peptides (USPs), consisting of 2–7 amino-acid residues, are a group of signaling molecules that regulate gene expression and protein synthesis under normal conditions in various diseases and ageing. USPs serve as a basis for the development of drugs with a targeted mechanism of action. The purpose of this review is to systematize the available data on USP transport involving POT and LAT transporters in various organs and tissues under normal, pathological and ageing conditions. The carriers of the POT family (PEPT1, PEPT2, PHT1, PHT2) transport predominantly di- and tripeptides into the cell. Methods of molecular modeling and physicochemistry have demonstrated the ability of LAT1 to transfer not only amino acids but also some di- and tripeptides into the cell and out of it. LAT1 and 2 are involved in the regulation of the antioxidant, endocrine, immune and nervous systems’ functions. Analysis of the above data allows us to conclude that, depending on their structure, di- and tripeptides can be transported into the cells of various tissues by POT and LAT transporters. This mechanism is likely to underlie the tissue specificity of peptides, their geroprotective action and effectiveness in the case of neuroimmunoendocrine system disorders.

Embryogenesis is a complex multi-stage process regulated by various signaling molecules including pineal and extrapineal melatonin (MT). Extrapineal MT is found in the placenta and ovaries, where it carries out local hormonal regulation. MT is necessary for normal development of oocytes, fertilization and subsequent development of human, animal and avian embryos. This review discusses the role of MT as a regulator of preimplantation development of the embryo and its implantation into endometrial tissue, followed by histo-, morpho- and organogenesis. MT possesses pronounced antioxidant properties and helps to protect the embryo from oxidative stress by regulating the expression of the NFE2L2, SOD1, and GPX1 genes. MT activates the expression of the ErbB1, ErbB4, GJA1, POU5F1, and Nanog genes which are necessary for embryo implantation and blastocyst growth. MT induces the expression of vascular endothelial growth factor (VEGF) and its type 1 receptor (VEGF-R1) in the ovaries, activating angiogenesis. Given the increased difficulties in successful fertilization and embryogenesis with age, it is of note that MT slows down ovarian aging by increasing the transcription of sirtuins. MT administration to patients suffering from infertility demonstrates an increase in the effectiveness of in vitro fertilization. Thus, MT may be viewed as a key factor in embryogenesis regulation, including having utility in the management of infertility.

Thymalin is a polypeptide complex isolated from the thymus and regulating the functions of the immune system. Thymalin is effective in therapy of acute respiratory syndrome, chronic obstructive bronchitis, and other immunopathology. Thymalin increases functional activity of T lymphocytes, but the targeted molecular mechanism of its biological activity requires further study. We studied the influence of thymalin on differentiation of human hematopoietic stem cells (HSC) and expression of CD28 molecule involved in the implementation of antiviral immunity in COVID-19 infection. It was found that thymalin reduced the expression of CD44 (stem cell marker) and CD117 (molecule of the intermediate stage of HSC differentiation) by 2-3 times and increased the expression of CD28 (marker of mature T lymphocytes) by 6.8 times. This indirectly indicates that thymalin stimulated differentiation of CD117+ cells into mature CD28+T lymphocytes. It is known that in patients with severe COVID-19, the number of CD28+, CD4+, CD8+T lymphocytes in the blood decreased, which attested to a pronounced suppression of immunity. It is possible that the antiviral effect of thymalin consists in compensatory stimulation of HSC differentiation into CD28+T lymphocytes at the stage of immunity suppression in unfavorable course of viral infection. Thymalin can be considered as an immunoprotective peptide drug for the prevention of COVID-19.

Melatonin (MT) and sirtuins (SIRT) are geroprotective molecules that hold back the aging process and the development of age-related diseases, including cardiovascular pathologies. Buccal epithelium (BE) sampling is a non-invasive procedure, yielding highly informative material for evaluating the expression of genes and proteins as well as the synthesis of molecules. Among these, MT and SIRTs are valuable markers of the aging process and age-related pathologies. The purpose of this study was to examine age-related expression patterns of these signaling molecules, in particular MT, SIRT1, SIRT3, and SIRT6 in BE of subjects of different ages with and without arterial hypertension (AH). We used real-time polymerase chain reaction (RT-PCR) and immunofluorescence analysis by confocal microscopy. We found that MT immunofluorescence intensity in BE decreases with aging, more evidently in AH patients. SIRT3 and SIRT6 genes expression and immunofluorescence intensity in BE was decreased in aging controls. In AH patients, SIRT1, SIRT3, and SIRT6 gene expression and immunofluorescence intensity in BE was decreased in relation to age and in comparison with age-matched controls. In conclusion, the evaluation of MT and sirtuins in BE could provide a non-invasive method for appraising the aging process, also when accompanied by AH.

There is a vast practice of using antimalarial drugs, RAS inhibitors, serine protease inhibitors, inhibitors of the RNA-dependent RNA polymerase of the virus and immunosuppressants for the treatment of the severe form of COVID-19, which often occurs in patients with chronic diseases and older persons. Currently, the clinical efficacy of these drugs for COVID-19 has not been proven yet. Side effects of antimalarial drugs can worsen the condition of patients and increase the likelihood of death. Peptides, given their physiological mechanism of action, have virtually no side effects. Many of them are geroprotectors and can be used in patients with chronic diseases. Peptides may be able to prevent the development of the pathological process during COVID-19 by inhibiting SARS-CoV-2 virus proteins, thereby having immuno- and bronchoprotective effects on lung cells, and normalizing the state of the hemostasis system. Immunomodulators (RKDVY, EW, KE, AEDG), possessing a physiological mechanism of action at low concentrations, appear to be the most promising group among the peptides. They normalize the cytokines’ synthesis and have an anti-inflammatory effect, thereby preventing the development of disseminated intravascular coagulation, acute respiratory distress syndrome and multiple organ failure.

It was shown that AEDG peptide (Ala-Glu-Asp-Gly, Epitalon) regulates the function of the pineal gland, the retina, and the brain. AEDG peptide increases longevity in animals and decreases experimental cancerogenesis. AEDG peptide induces neuronal cell differentiation in retinal and human periodontal ligament stem cells. The aim of the study was to investigate the influence of AEDG peptide on neurogenic differentiation gene expression and protein synthesis in human gingival mesenchymal stem cells, and to suggest the basis for the epigenetic mechanism of this process. AEDG peptide increased the synthesis of neurogenic differentiation markers: Nestin, GAP43, &beta, Tubulin III, Doublecortin in hGMSCs. AEDG peptide increased Nestin, GAP43, &beta, Tubulin III and Doublecortin mRNA expression by 1.6&ndash, 1.8 times in hGMSCs. Molecular modelling method showed, that AEDG peptide preferably binds with H1/6 and H1/3 histones in His-Pro-Ser-Tyr-Met-Ala-His-Pro-Ala-Arg-Lys and Tyr-Arg-Lys-Thr-Gln sites, which interact with DNA. These results correspond to previous experimental data. AEDG peptide and histones H1/3, H1/6 binding may be one of the mechanisms which provides an increase of Nestin, GAP43, &beta, Tubulin III, and Doublecortin neuronal differentiation gene transcription. AEDG peptide can epigenetically regulate neuronal differentiation gene expression and protein synthesis in human stem cells.

The data on the role of hypoxia-inducible factor, HIF-1, in the development of immunopathology (infectious, inflammatory, and autoimmune diseases), cancer (of the lung, brain, female reproductive system, urinary bladder, and pancreas), diabetes mellitus, and Alzheimer’s disease are analyzed. The data on the genes involving cell differentiation, apoptosis, and proliferation, the expression of which is regulated by HIF-1, are described. HIF-1 activates the expression of the telomerase gene and increases the replicative lifetime of human lung fibroblasts under hypoxic conditions. HIF-1 may be a molecular marker of cell aging and metabolism, as well as a potential therapeutic target for the treatment of age-related diseases.

The data on the molecular mechanisms of normal and pathological apoptosis are summarized. Three phases of apoptosis are distinguished: signal, effector, and degradation. The signal phase includes the extrinsic (caspase-dependent) and extrinsic (mitochondrial) pathways. Molecular markers of extrinsic and extrinsic apoptotic pathways play an important role in the diagnostics and treatment of immune, bronchopulmonary, excretory, and cardiovascular system pathologies, oncology, and senescence. This review considers the initiator caspases-8 and -9 and the effector caspase-3 as the molecular markers of the caspase-dependent apoptosis. The main molecular markers of the mitochondrial (or caspase-independent) apoptosis are p53, p21, and p16 proteins, which respond to DNA damage and are involved in cellular senescence, as well as chaperon prohibitin and flavoprotein apoptosis-inducing factor.

Short peptides are molecules with small molecular weight, capable of penetrating the cell membrane and nuclear membrane for epigenetic regulation of gene expression, including the genes responsible for cell differentiation. The direction of cell differentiation induction depends on the peptide structure and concentration. AEDG and AEDP peptides induce differentiation of pluripotent cells in the epidermis, mesenchyme and nervous tissue. Peptides KE, AED, KED, AEDG and AAAAEKAAAAEKAAAAEK activate neural differentiation. Peptides AEDL and KEDW induce lung and pancreatic cell differentiation. Differentiation of immune cells is stimulated by KE, DS, (Nα-(γ-E)-E), K(Н-E-OH)-OH, AED, KED, EDA, and KEDG peptides. IRW, GRGDS and YCWSQYLCY peptides activate osteogenic differentiation of stem cells. KE, AEDL, and AEDG peptides also induce plant cells differentiation. Short peptides can take part in activation of the signaling pathways regulating expression of differentiation genes. They can interact with histones changing the availability of genes for transcription, regulate gene methylation and activate or inhibit their expression, as well as directly interact with the DNA. Research in the area of directed stem cell differentiation by peptide regulation is of special importance for developing innovative approaches to molecular medicine and cell therapy.

Skin aging is an current problem of modern geriatric cosmetology. One promising method to decelerate the process of age-related skin changes is the use of cosmetics with short peptides. The goal of the work was to study the effect of peptide KE (Lys-Glu, Vilon) on the expression of aging markers of human fibroblasts in an in vitro model. The expression of collagen type 1 and sirtuin 6 was studied with immunofluorescent confocal microscopy in “young” and “old” cultures of skin fibroblasts. It has been found that the area of expression of collagen type 1 and sirtuin 6 decreases by 3.5 and 3.6 times, respectively, in skin fibroblast cultures with aging. Peptide KE increases the expression area of collagen type 1 in old skin fibroblast cultures by 83%; the expression area of sirtuin 6 in young and old cultures of skin fibroblasts increased by 1.6 and 2.6 times, respectively. Thus, peptide KE increases the functional activity of skin fibroblasts and decelerates their senescence.

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder of elderly and old-aged people. Cerebrospinal fluid (CSF) and peripheral tissues—lymphocytes and platelets, buccal and olfactory epithelium, and skin fibroblasts—are used for intravital diagnostics of the expression of signaling molecules (AD markers). There are several changes in the production of hyperphosphorylated τ-protein form, BACE1, and peptide Aβ42 in CSF in the case of AD, but CSF sampling can have a number of side effects. Biopsies of the epithelium and portions of blood are a less traumatic method of obtaining tissue samples for AD diagnosis. An increase in the expression of the hyperphosphorylated form of τ-protein is shown in the blood lymphocytes of AD patients. An increase in the content of high molecular forms of phosphorylated τ protein and amyloid precursor protein (APP) was also detected in the platelets of AD patients. Changes in the amount of two miRNA families, miR-132 and miR-134, were detected in blood cells 1–5 years before the manifestation of clinical signs of AD. An increase in the bound-calcium concentration, Aβ40 and Aβ42 peptide synthesis, and τ protein was observed in AD skin fibroblasts. In olfactory and buccal epithelia, an increase in the expression of hyperphosphorylated τ-protein form and Aβ peptide was detected in AD patients. The detection of AD markers in peripheral tissues available for biopsy is highly important for intravital diagnostics, prevention, and targeted treatment of AD.

We studied the expression of MMP-2, MMP-9, and inhibitor TIMP-1 in myocardial autopsy samples from subjects of different age and in cardiomyocyte cultures in the norm and in dilated cardiomyopathy. In autopsy samples of normal myocardium and in cardiomyocyte cultures, expression of molecules involved in extracellular matrix remodeling did not change during aging. In dilation cardiomyopathy, expression of MMP-2, MMP-9, and TIMP-1 and their ratios in autopsy material and in cultures was elevated by 1.5-9 times. Remodeling of extracellular matrix plays an important role in the pathogenesis of dilated cardiomyopathy. MMP-2, MMP-9, and their inhibitor TIMP-1 and the MMP/TIMP ratios can be regarded as promising predictors of dilated cardiomyopathy and used for evaluation of the effectiveness of treatment of this conditions in patients of different ages.

Peptides are characterized by their wide range of biological activity: they regulate functions of the endocrine, nervous, and immune systems. The mechanism of such action of peptides involves their ability to regulate gene expression and protein synthesis in plants, microorganisms, insects, birds, rodents, primates, and humans. Short peptides, consisting of 2–7 amino acid residues, can penetrate into the nuclei and nucleoli of cells and interact with the nucleosome, the histone proteins, and both single- and double-stranded DNA. DNA–peptide interactions, including sequence recognition in gene promoters, are important for template-directed synthetic reactions, replication, transcription, and reparation. Peptides can regulate the status of DNA methylation, which is an epigenetic mechanism for the activation or repression of genes in both the normal condition, as well as in cases of pathology and senescence. In this context, one can assume that short peptides were evolutionarily among the first signaling molecules that regulated the reactions of template-directed syntheses. This situation enhances the prospects of developing effective and safe immunoregulatory, neuroprotective, antimicrobial, antiviral, and other drugs based on short peptides.

The effect of a pineal gland polypeptide complex, Pineamin, on urine excretion of 6-sulfatoxymelatonin (6-SOMT) was investigated by immunoenzyme assay in 55 elderly patients with decreased melatonin formation. Pineamin at a dose of 100 mg increased the level of 6-SOMT excretion in overnight urine by 1.9 times in comparison with the respective indicator before the treatment. A similar effect was previously obtained upon the administration of Epitalamin, which also facilitated the restoration of melatonin synthesis in human and animal pineal glands affected by aging. Hence, Pineamin and Epitalamin exhibit a one-directional stimulating property with respect to the melatonin-forming function of the pineal gland in elderly people.

EDL peptide produced a nephroprotective effect on experimental models gentamycin-induced nephropathy and ischemia/reperfusion kidney injury in rats. The nephroprotective effect of EDL peptide manifested in prevention of oliguria and retention azotemia, a decrease in proteinuria and sodium excretion, prevention of critical decrease in activities of antioxidant enzymes, suppression of LPO, and normalization of energy supply to kidneys cells. Our findings confirm the prospects of further studies of the nephroprotective properties of peptide EDL in various pathologies of the kidneys.

The review is dedicated to one of the molecular factors of skin aging essential for cosmetic medicine for the elderly. Cell renewal processes slow down with aging, and the proliferation–apoptosis equilibrium shifts towards cell death. One of the pivotal apoptotic markers is transcription factor p53. Its expression in skin keratinocytes increases under the influence of ultraviolet radiation. Mutant forms of p53 have been revealed in 70% of keratinocytes of skin exposed to ultraviolet radiation. On the one hand, suppression of p53 expression decreases apoptosis in skin cells, thereby decelerating senescence. On the other hand, it promotes the development of neoplasms in the skin. Thus, support of the physiological balance of p53 expression in skin cells is important for theoretical and practical gerontocosmetology. In addition, p53 can be used as a marker for skin cell functionality in response to anti-aging cosmetic products and to instrumental cosmetology.

In the cell culture experiments, the AEDL peptide proved to be an efficient agent stimulating the cell renewal processes and the enhancement of the functional activity of bronchial epithelial cells. A presumed target of the peptide action is a DNA molecule. The work studies the peptide binding with high-molecular DNA in solutions with different ionic strengths. The spectral (UV spectophotometery and circular dichroism) and hydrodynamic (viscosimetry) methods show that, under the experimental conditions, the AEDL peptide forms a complex with DNA and that nitrogen bases are involved in the binding. The character of spectral changes in DNA suggests a possible interaction of the AEDL peptide with DNA in the major furrow at the guanine N7 site without a visible distortion of the double helix structure.

Primary stem cells, after several cell divisions, enter into a senescence state, that is characterized by alterations to spindle-shape typical morphology. This concern is one of the main problems in the use of human mesenchymal stem cells (hMSCs) in clinical applications which demand cells in large numbers. Short peptides had geroprotective properties and stimulated stem cell differentiation. The aim of the study is to demonstrate the role of AEDG and KED peptides in maintaining oral hMSCs morphology and functions over long-term expansion. 2 types of hMSCs were investigated: human periodontal ligament stem cells (hPLSCs) and human gingival mesenchymal stem cells (hGMSCs). Cells at the 25th passage were divided into 3 groups: 1 - control (without adding peptide), 2 - treated with AEDG peptide, 3 - treated with KED peptide. Cell cultures were analyzed by an immunofluorescence method and RT-PCR on the p16 and p21 senescence markers expression. AEDG peptide decreased p16 and p21 mRNA expression by 1.56-2.44 times in comparison with the control group. KED peptide decreased p16 and p21 mRNA expression by 1.82-3.23 times in comparison with the control group. These results were confirmed by immunofluorescent visualization. AEDG and KED peptides could be used as supplementary substances in a culture medium to delay the expression of senescence markers in long term stem cell cultivation in order to promote the large-scale in vitro expansion necessarily required for stem cell therapy clinical application. The data obtained confirm the geroprotective effect of AEDG and KED peptide, which was shown early in animal and cells models.

Peptide KE exhibits immunoprotective, geroprotective, and oncostatic activities and stimulates functional activity of fibroblasts. The KE motif is present in amino acid sequences of some cytokines and peptide hormones functionally similar to KE peptide. However, the relationship between the presence of KE motif and protein functions on the scale of known human proteome has not yet received sufficient attention. The incidence of bioregulatory peptide KE in proteins of various functional groups constituting human proteome is studied. The study is carried out with the use of the available data on the human proteome (UniProt portal) comprising 20,417 proteins. The levels of KE motifs were maximum in cytoplasmic and nuclear proteins, while the presence of KE in the membrane and all other proteins was the minimum. KE peptide molecules released from nuclear proteins during limited proteolysis can bind to DNA and regulate gene expression.

We studied the effect of peptide AEDG on telomere length and mitotic index of PHA-stimulated blood lymphocytes from young (18-22 years, N=5) and middle-aged (49-54 years, N=6) men. In the younger age group, no significant changes in the mitotic index were detected, while in the middle-aged group, a decrease in this parameter was found in one case. The relative length of telomeric regions of metaphase chromosomes was evaluated by in situ fluorescence hybridization with DNA probes specific to telomeres. After incubation with peptide AEDG, significant changes in the relative telomere length were found in 7 of 11 individuals (3 cases in the younger age group and 4 cases in the middle age group). Significant increase in telomere length after exposure to peptide AEDG was revealed in 5 cases, including two individuals of the younger age group (by 41 and 55%) and three individuals of the middle age group (by 156, 18, and 76%). In one individual of the younger age group and in one of the middle-age group, a significant decrease in telomere length (by 37 and 15%, respectively) was found. A tendency to normalization of telomere lengths was noted: this parameter increased in individuals with initially lower telomere length relative to the group mean value and decreased in individuals with initially longer telomeres compared to the mean length in the group.

It has been demonstrated that short peptides play an important role in the transmission of biological information, modulation of transcription, and restoring genetically conditioned alterations occurring with age. Peptidergic regulation of homeostasis occupies an important place in physiological processes, which lead to the aging of cells, tissues, and organs, consisting in the involution of major regulatory systems—the nervous, the endocrine, and the immune. The effect of AED (Ala-Glu-Asp), KED (Lys-Glu-Asp), KE (Lys-Glu), AEDG (Ala-Glu-Asp-Gly) peptides and their compound on neuronal differentiation of human periodontal ligament stem cells (hPDLSCs) was studied by immunofluorescence and western blot analysis. Growth-Associated Protein 43 (GAP43), which implements neurotransmission mechanisms and neuroplasticity, demonstrated an increased expression in hPDLSCs cultured with a compound of all studied peptides and with KED alone. The peptide compound and KED, increase the expression of Nestin (neurofilament protein), expressed in early neuronal precursors in hPDLSCs cultures. Thus, the compound of peptides AEDG, KE, AED, and KED could promote the neuronal differentiation of hPDLSCs and be a promising tool for the study of peptides as a modulator of neurogenesis in neurodegenerative diseases studied in animal models.

We compared the expression of Aβ42 peptide, τ-protein, and α-synuclein in the substantia nigra and skin fibroblasts of elderly and senile patients with Parkinson's disease and subjects without neuropathology. Expression of markers in the studied tissues was assessed by immunohistochemical and immunocytochemical methods. The expression of Aβ42 peptide, τ-protein, and α-synuclein in the substantia nigra of elderly and senile patients with Parkinson's disease was higher by 11-31 times than in subjects without neuropathology. In skin fibroblasts of patients with Parkinson's disease, the expression of Aβ42 peptide and α-synuclein was 3-14 times higher than in subjects without neuropathology, and expression of τ-protein did not significantly differ in the studied groups. Thus, immunocytochemical analysis of the expression Aβ42 peptide and α-synuclein in skin fibroblasts can be a simple method of early diagnosis of Parkinson's disease in elderly persons.

KED and EDR peptides prevent dendritic spines loss in amyloid synaptotoxicity in in vitro model of Alzheimer’s disease (AD). The objective of this paper was to study epigenetic mechanisms of EDR and KED peptides’ neuroprotective effects on neuroplasticity and dendritic spine morphology in an AD mouse model. Daily intraperitoneal administration of the KED peptide in 5xFAD mice from 2 to 4 months of age at a concentration of 400 μg/kg tended to increase neuroplasticity. KED and EDR peptides prevented dendritic spine loss in 5xFAD-M mice. Their action’s possible molecular mechanisms were investigated by molecular modeling and docking of peptides in dsDNA, containing all possible combinations of hexanucleotide sequences. Similar DNA sequences were found in the lowest-energy complexes of the studied peptides with DNA in the classical B-form. EDR peptide has binding sites in the promoter region of CASP3, NES, GAP43, APOE, SOD2, PPARA, PPARG, GDX1 genes. Protein products of these genes are involved in AD pathogenesis. The neuroprotective effect of EDR and KED peptides in AD can be defined by their ability to prevent dendritic spine elimination and neuroplasticity impairments at the molecular epigenetic level.

The EDR peptide (Glu-Asp-Arg) has been previously established to possess neuroprotective properties. It activates gene expression and synthesis of proteins, involved in maintaining the neuronal functional activity, and reduces the intensity of their apoptosis in in vitro and in vivo studies. The EDR peptide interferes with the elimination of dendritic spines in neuronal cultures obtained from mice with Alzheimer’s (AD) and Huntington’s diseases. The tripeptide promotes the activation of the antioxidant enzyme synthesis in the culture of cerebellum neurons in rats. The EDR peptide normalizes behavioral responses in animal studies and improves memory issues in elderly patients. The purpose of this review is to analyze the molecular and genetics aspects of the EDR peptide effect on gene expression and synthesis of proteins involved in the pathogenesis of AD. The EDR peptide is assumed to enter cells and bind to histone proteins and/or ribonucleic acids. Thus, the EDR peptide can change the activity of the MAPK/ERK signaling pathway, the synthesis of proapoptotic proteins (caspase-3, p53), proteins of the antioxidant system (SOD2, GPX1), transcription factors PPARA, PPARG, serotonin, calmodulin. The abovementioned signaling pathway and proteins are the components of pathogenesis in AD. The EDR peptide can be AD.

This review describes the expression of neuroendocrine and immune signaling molecules in human endometrial cells under normal and pathological conditions and during aging. Human endometrial cells synthesize estrogen, progesterone, estradiol, progestin, cell-adhesion molecules (integrins α1β1, α4β1, αVβ3, L-selectin, E-cadherin, and MUC1), growth factors (TGF, EGF, HB-EGF, and IGF), cytokines (IL-1, IL-2, INF-α, IL-12, CXCL10, CXCL11, and CXCR3), various immune-cell markers (CD68, CD105, CD163, CD16, CD56, CD4, and CD8), and heat-shock proteins (HSP60, HSP70, HSP90, VEGF, and MMP). Aberrations in their expression levels underlie such socially significant diseases as endometriosis, endometrial cancer, and infertility. Thus, investigation of neuroendocrine and immune interactions among endometrial cells can be used for the purposes of drug development, differential diagnostics of endometrial cancer, and increasing the efficacy of in vitro fertilization.

The polypeptide complex of the epiphysis and the peptide AEDG, constructed on the basis of its amino acid analysis, exert similar biological effects. Both bioregulators normalize melatonin synthesis in the pineal gland, functioning of the brain, eye retina, cardiovascular, endocrine, and immune systems; they also act as antioxidants, stress-protectors, and geroprotectors. Within the epiphysis polypeptide complex, free amino acids (3.26%), dipeptides (23.19%), tripeptides (50.72%), tetrapeptides (22.10%), and pentapeptides (0.72%) were revealed by mass spectrometry and HPLC. Peptide AEDG was detected among the tetrapeptides of the epiphysis polypeptide complex by selective reaction monitoring method. The biological effects of the epiphysis polypeptide complex are determined by the effect of its component AEDG.

The expression of Aβ42, and τ-protein, and p16 and p53 proteins was analyzed in the buccal epithelium of elderly and senile patients with Alzheimer’s disease. We revealed enhanced synthesis of Alzheimer’s disease markers Aβ42 (by 15-30 times) and τ-protein (by 5 times) in comparison with the corresponding values in people without neurodegenerative pathology of the same age groups. In addition, increased synthesis of proteins of cell aging and apoptosis p16 (by 6-10 times) and p53 (by 2-3 times) was observed in patients in comparison with age-matched persons without neuropathology. These data suggest that complex analysis of the expression of Aβ42, τ-protein, p16, and p53 in the buccal epithelium is a promising method for in vivo diagnosis of Alzheimer’s disease and assessment of the rate of aging during the development of this pathology.

Short peptides vesugen and D-7 have stimulated proliferation-associated protein Ki-67 decreased during aging in tissue-specific cell cultures received from young and old animals and in dissociated vascular endothelial cell cultures. Peptides vesugen and D-7 have interacted with promoter region of MKI67 gene coding protein Ki-67 that was obtained using methods of molecular docking. Both peptides have contacted with core promoter 5'-agcctcaaccatcaggaaaacaagagt-3' located in MKI67 gene from -14 to +12 base pairs relative to the transcriptional initiation site through sequence CATC(ENSG00000148773). Thus, vasoprotective effect of peptide vesugen revealed previously in elder people could be realized through epigenetic regulation of Ki-67 gene expression.

Cytokines CCL11 (eotaxin) and HMGB1 (alarmin 1) are molecular markers of ageing and neurological, cardiovascular, and immune diseases. Created at the St. Petersburg Institute of Bioregulation and Gerontology, these short peptides are known to regulate gene expression and protein synthesis. They promote decreased mortality and deceleration of pathology in the elderly. The review suggests that the dipeptide vilon (Lys-Glu) and tetrapeptide epitalon (Ala-Glu-Asp-Gly) are involved in regulation of the CCL11 and HMGB1 genes as activators of their expression. The geroprotective effect of vilon and epitalon is probably due to the suppression of these genes.

Polypeptide complex isolated from calf kidneys stimulates the processes of cell renewal in organotypic kidney tissue cultures from young and old rats. The polypeptide complex enhances expression of proliferation marker Ki-67 and reduces expression of proapoptotic peptide p53 in kidney explants obtained from young and old animals. Short peptides T-31 (AED) and T-35 (EDL) also stimulate proliferation and reduce apoptosis of the kidney cells, but to a lesser degree than the polypeptide complex. The results provide the basis for further investigation of the polypeptide complex as a preparation for the therapy of kidney diseases, including age-related pathologies.

Data on endothelial signaling molecules involved in homeostasis regulation and development of age-associated disorders are summarized. Regulation of the endothelium function is implemented by a system of signaling molecules: NO, NO synthase, prostacyclin, thrombomodulin, thromboxane, antithrombin, endothelins, fibronectin, von Willebrand factor, etc. Changes in their synthesis can cause arterial hypertension, atherosclerosis, ischemic heart disease, myocardial infarction, and other age-related disorders. Study of the molecular mechanisms mediating endothelial functioning is essential for developing new methods of diagnostics and a treatment for age-associated cardiovascular diseases.

Irisin produced by muscles during exercise and promoting fat burning also exhibits geroprotective effect and induces telomere elongation in normal somatic cells. Special attention is paid to studies of the role of peptides Lys-Glu, Glu-Asp-Arg, and Ala-Glu-Asp-Gly in epigenetic regulation of irisin content. The data suggest that the immunomodulatory peptide Lys-Glu and neuroprotective peptide Glu-Asp-Arg modulate the life span by modulating irisin gene expression.

In primary culture of mouse hippocampal neurons, peptide EDR (200 ng/ml) under conditions of amyloid synaptotoxicity (a model of Alzheimer’s disease) increased the number of mushroom spines by 71% and returned this parameter to the normal level. Under the same conditions, tripeptide KED (200 ng/ml) increased the number of mushroom spines in hippocampal neurons by 20%. Tripeptide EDR can be recommended for further experimental study as a candidate neuroprotective agent for prevention and treatment of Alzheimer’s disease.

Peptides Glu-Asp-Arg and Lys-Glu-Asp stimulate serotonin expression in aging cultures of brain cortex cells. Peptide regulation of 5-tryptophan hydroxylase gene encoding the enzyme involved in serotonin synthesis was demonstrated by the molecular docking method. The CCTGCC nucleotide sequence in 5-tryptophan hydroxylase gene was found to be complementary to these peptides. Hence, Glu-Asp-Arg and Lys-Glu-Asp peptides epigenetically regulate serotonin synthesis in the brain cortex, which indicates their neuro- and geroprotective activities.

In this work, it was shown that short peptides, such as vilon, thymogen, crystagen and R-1, possess different age-associated immunoprotecting properties in the spleen. Both the R-1 and vilon peptides were found to activate T-helper cells. T-Helper activation by vilon was based on the inhibition of cellular apoptosis, whereas R-1 acted through positive stimulation of cellular proliferation and differentiation. Thymogen was found to be an activator of B-lymphocytes and acted through the inhibition of apoptosis, as well as by the stimulation of spleen cells proliferation. Crystagen was also found to activate the B-cell immunity system but had no effect on the processes of cellular renewal in the spleen during aging.

Peptide bioregulators promote restoration of the physiological activity of the retina in retinitis pigmentosa in older adults and in animal models. The molecular mechanism of the physiological activity of peptides is associated with their ability to epigenetically regulate the synthesis of protein markers of the differentiation of retinal neurons and pigment epithelium.

Data on various aspects of the molecular and cellular mechanism of the biological activity of short peptides used as potential drugs were analyzed. Based on the published data and our own results, a possible mechanism of the penetration of short peptides into the cytoplasm and cell nucleus is considered. In addition, the possibility of the involvement of short peptides in the mechanisms of the epigenetic regulation of gene expression via their complimentary interaction with promoter regions of genes in DNA is substantiated.

The review contains different aspects indicating the participation of cytokines in aging-associated diseases. Authors reveal the role of short peptides in molecular mechanisms of homeostatic regulation in immune, cardiovascular, haemostatic systems which is based on the literature data and own experimental data. It is established that short peptides realize their geroprotective effect by changing gene expression of immune and proinflammatory cytokines and g-interferon.