It was found earlier that the synthetic fragment corresponding to the 60–76 sequence of the extracellular domain of the receptor for advanced glycation end products (RAGE) had a protective effect on animal and cellular models of Alzheimer’s disease. It was proposed that this effect was mediated via the interaction of the peptide with beta-amyloid (Aβ), which was one of the RAGE ligands, by inhibiting the formation of toxic Aβ oligomers. The aim of this study was an application of physicochemical methods to an investigation of the ability of the 60–76 peptide to prevent the Aβ40 oligomerization in solution in comparison with the nonprotective 65–76 truncated peptide. The dynamics of the formation of the Aβ40 fibrils in the presence of the peptides was evaluated using thioflavin T. The relative sizes of oligomers were determined by dynamic light scattering. The peptide binding to Aβ40 was examined by fluorescence titration. We demonstrated by the two methods that the peptide corresponding to the 60–76 sequence of RAGE considerably inhibited (by more than 90%) the formation of oligomers and fibrils of Aβ40 distinct from the 65–76 peptide. In addition, we found that the protective effect of the peptides and their ability to inhibit the Aβ40 oligomerization did not correlate with their binding to the monomeric/tetrameric Aβ40. We confirmed in vitro the hypothesis that the protective activity of the synthetic 60–76 fragment of RAGE was associated with its ability to inhibit the Aβ oligomerization.

The receptor for advanced glycation end products (RAGE) plays an essential role in Alzheimer's disease (AD). We previously demonstrated that a fragment (60-76) of RAGE improved the memory of olfactory bulbectomized (OBX) and Tg 5 x FAD mice - animal models of AD. The peptide analog (60-76) with protected N- and C-terminal groups was more active than the free peptide in Tg 5 x FAD mice. This study investigated proteolytic cleavage of the RAGE fragment (60-76) and its C- and N-terminally modified analog by blood serum using HPLC and mass spectrometry. The modified peptide was proteolyzed slower than the free peptide. Degrading the protected analog resulted in shortened fragments with memory-enhancing effects, whereas the free peptide yielded inactive fragments. After administering the different peptides to OBX mice, their performance in a spatial memory task revealed that the effective dose of the modified peptide was five times lower than that of the free peptide. HPLC and mass spectrometry analysis of the proteolytic products allowed us to clarify the differences in the neuroprotective activity conferred by administering these two peptides to AD animal models. The current study suggests that the modified RAGE fragment is more promising for the development of anti-AD therapy than its free analog.

Using machine-learning methods based on self-organising Kohonen maps, the results of numerical simulation of the acceleration of electrons during the interaction of high-power laser radiation with plasma are analysed and classified. The particle-in-cell (PIC) method is used to simulate the interaction in a wide range of parameters (laser intensity and plasma concentration). For each set of parameters, the spectrum of accelerated electrons is found, based on which the charge, average energy, and relative energy spread of accelerated electrons are calculated. Using the obtained values as input parameters of the map, the classification of various acceleration regimes is performed. The developed scheme can be used to identify the optimal acceleration regimes under more realistic conditions, considering a larger number of parameters.

The solid-phase synthesis and purification of the 1-40 sequence of the human beta-amyloid were optimized, resulting in a preparation of a product with a high yield and homogeneity more than 95%. The synthetic peptide is capable of forming oligomers. This fact was confirmed by electrophoresis in the polyacrylamide gel with a subsequent immunoblotting and fluorescence spectrophotometry using the thioflavin T dye. An available method for a production of the highly specific anti-beta-amyloid antibodies with a high titer was developed. These antibodies recognized both monomeric and oligomeric forms of the 1-40 peptide of beta-amyloid under the immunoblotting conditions.

The use of rectangular-shaped microstructures at the front surface of a solid target is shown to improve gamma-ray generation by 2–3 orders of magnitude, compared to the case of a planar target, when irradiated by laser pulses with an intensity of 1.13 × 1022 W cm−2. Also, it is observed that the laser energy absorption rate increases more than 10 times, up to 57%. The analysis of the simulation results suggests that in the case of relatively narrow microstructure elements, the gamma-ray generation mechanism is similar to that in the case of laser pulse normally incident onto a planar target, but with differences in the electron trajectories. The optimal dimensions of rectangular-shaped microstructured target have been found with the help of 3D particle-in-cell simulations.

The membrane receptor for advanced glycation endproducts (RAGE) is involved in the development of a number of pathological conditions, including Alzheimer’s disease (AD), in which the receptor overexpression in brain cells and its increasing activity is observed. We have previously shown that the synthetic fragment RAGE (60–76), administered intranasally, could prevent the disturbance of the spatial memory of olfactory bulbectomized mice, that develop features of AD. We suggested that N-terminal amino function of the peptide protected with acetic group and C-terminal carboxyl group replaced with amide, would increase the stability of this peptide in in vivo experiments, and this protected peptide would show higher activity compared to the original free one. In the current study the protected peptide analog Ac-(60–76)-NH 2 was synthesized. The activity of the peptide (60–76) and its protected analog has studied in transgenic 5xFAD mice, which represent a generally accepted model of AD. The memory testing was performed in the Morris water maze. It was shown that intranasal administration of these peptides to transgenic 5xFAD mice for two months preserved the spatial memory of animals, and both peptides exhibited the same ability to prevent the spatial memory. The difference in the activity of the tested peptides was revealed 7 days after drug administration had been over, and only animals, previously received the modified peptide Ac-(60–76)-NH 2 , showed the ability to find the Morris water maze learning sector. The animals received the peptide (60–76) lost their ability to find the learning sector after 7 days and were completely disoriented. The data obtained allow us to conclude that the modified fragment (60–76) with protected N- and C-terminal functional groups has a more pronounced and long lasting protective effect compared to the free peptide (60–76). Thus, Ac-(60–76)-NH 2 is a promising candidate for development of the drug for the treatment of Alzheimer’s disease.

Activation of receptor for advanced glycation end products (RAGE) plays an essential role in the development of Alzheimer's disease (AD). It is known that the soluble isoform of the receptor binds to ligands and prevents negative effects of the receptor activation. We proposed that peptide fragments from RAGE prevent negative effects of the receptor activation during AD neurodegeneration. We have synthesized peptide fragments from surface-exposed regions of RAGE. Peptides were intranasally administrated into olfactory bulbectomized (OBX) mice, which developed some characteristics similar to AD neurodegeneration. We have found that only insertion of fragment (60-76) prevents the memory of OBX mice. Immunization of OBX mice with peptides showed that again only (60-76) peptide protected the memory of animals. Both intranasal insertion and immunization decreased the amyloid-β (Aβ) level in the brain. Activity of shortened fragments of (60-76) peptide was tested and showed only the (60-70) peptide is responsible for manifestation of activity. Intranasal administration of (60-76) peptide shows most protective effect on morpho-functional characteristics of neurons in the cortex and hippocampal areas. Using Flu-(60-76) peptide, we revealed its penetration in the brain of OBX mice as well as colocalization of Flu-labeled peptide with Aβ in the brain regions in transgenic mice. Flu-(60-76) peptide complex with trimer of Aβ was detected by SDS-PAGE. These data indicate that Aβ can be one of the molecular target of (60-70) peptide. These findings provide a new peptide molecule for design of anti-AD drug and for investigation of RAGE activation ways in progression of AD neurodegeneration.

Six synthetic peptides overlapping a fragment 60–76 of the receptor for advanced glycation end products (RAGE) were studied on a protective effect on spatial memory of animals in the experimental model of Alzheimer’s disease. It was shown that only a peptide corresponding to the fragment 60–70 of RAGE exhibits a therapeutic activity. Intranasal administration of this peptide into bulbectomized mice, which develop neurodegenerative features of the Alzheimer type, completely protects animal memory. Thus, it was found that the N -terminal region (60–70) within the peptide sequence 60–76 of RAGE is responsible for the revealed protective effect. The synthetic peptide RAGE-(60–70) could be the basis for the development of a new drug for the treatment of Alzheimer’s disease.

The receptor for advanced glycation end products (RAGE) plays an essential role in the development of Alzheimer's disease. Activation of RAGE causes brain inflammation, oxidative stress and secretion of beta-amyloid. It is known that the soluble isoform of receptor (sRAGE), which lacks the transmembrane and cytosolic domains, binds to ligands and prevents negative effects of the receptor activation in in vivo and in vitro experiments. We proposed that peptide fragments from sRAGE would demonstrate the same biological activity. RAGE fragments were prepared with standard Fmoc/Butprotocol of solid-phase peptide synthesis. NMRI mice were used after olfactory bulbectomy (OBX) which induced behavioral, morphological and biochemical signs of the Alzheimer's type degeneration. In 2 weeks after the surgery peptides were intranasally administrated in a dose of 20 mg per mouse during 15 days. Murine memory was tested in the Morris's water maze. We used Nissl staining to observe the morphological state of neurons in the temporal cortex and areas of CA1 and CA3 of the hippocampus. We counted the neuronal density, the percentage of normal neurons and neurons with pathologies. We selected and synthesized ten peptide fragments from unstructured surface-exposed regions of RAGE. We found that after intranasal administration of peptides only fragment (60–76) effectively prevents murine memory from impairment. Six overlapping fragments of RAGE (60–76) peptide were synthesized to find a site responding for the therapeutic effect. Tests carried out with these fragments showed that only (60–70) peptide is responsible for preventing animal memory impairment. Fragments (60–76) and (60–70) block the development of neuronal pathology in OBX mice. However, some N-terminal fragments which do not have significant activity in Morris's test also improve the morpho-functional state of neurons in OBX animals, but not so efficient in several aspects. There is a correlation between memory improvement activity and maintenance of neuronal morphology on a normal level after intranasal administration of RAGE fragment. Peptides (60–76) and (60–70) are active in both tests. Several N-terminal fragments also protect morphological state of neurons, but less noticeably, which corresponds with the absence of effect in Morris's test. Supported by RFBR Grant 15–04–01360, 17–34–80016 ”moleva.

Прионный белок является одной из мембранных мишеней бета-амилоида, основного нейротоксического агента при болезни Альцгеймера. Нами был осуществлен выбор и синтез фрагментов прионного белка 17–33, 23–33, 95–110 и 101–115, ответственных за связывание с бета-амилоидом. Было изучено влияние иммунизации пептидами на развитие признаков болезни у животных с экспериментально индуцированной формой болезни Альцгеймера. Показано, что иммунизация свободным пептидом 17–33 и белковыми конъюгатами пептидов 23–33 и 101–115 приводит к восстановлению состояния пространственной памяти животных. Также показано, что иммунизация пептидом 17–33 приводит к снижению уровня мозгового бета-амилоида и восстановлению морфофункциональных показателей мозга.

The prion protein is considered as one of the membrane targets of the neurotoxic beta-amyloid during development of Alzheimer’s disease. We chose and synthesized peptide fragments that corresponded to the 17–33, 23–33, 95–110, and 101–115 sequences of the prion protein and are responsible for the betaamyloid binding. The effect of immunization with the peptides on the development of symptoms of Alzheimer’s disease was investigated on animals with an experimentally induced form of the disease. Immunization with either free 17–33 peptide or with protein conjugates of the 23–33 and 101–115 peptides was shown to restore spatial memory of the animals. Immunization with the 17–33 peptide was also shown to decrease the level of brain beta-amyloid and to recover morphofunctional parameters of the brain.

The ability of some synthetic peptides modeling the potentially important regions of four membrane proteins, known as cell targets for beta-amyloid, to restore the spatial memory of animals in an experimental model of Alzheimer’s disease has been studied. Nine fragments of the protein receptor for advanced glycation end products (RAGE), which, according to X-ray structure analysis data, repeat all its exposed nonstructural regions, have been synthesized. The effect of these peptides and of earlier synthesized immunoprotective fragments of three other proteins (alpha7-type acethylcholine receptor, the prion protein, and the neurotrophin receptor p75) has been studied on intranasal administration, which excludes the development of the immune response to the peptide. It has been shown that only one fragment, RAGE (60–76), exhibits a therapeutic activity, by restoring the spatial memory of bulbectomized mice and decreasing the level of the brain beta-amyloid.

Receptor p75 is a classical membrane receptor, which consists of an extracellular region, a transmembrane region, and an intracellular C-terminus death domain. p75 is involved in the activation of neurotrophic factors and plays an essential role in the regulation of cell functions such as proliferation, differentiation, synaptogenesis, neuronal plasticity, and survival or apoptosis. It is supposed that p75 accelerates the positive effects of neurotrophins being a part of the complex with the Trk receptor; however, in the absence of Trk receptors, the interaction between p75 and neurotrophins leads to cell apoptosis. The interest in the p75 receptor has increased dramatically in the past few years, as it has been shown that p75 may play a crucial role in the genesis of neurodegenerative disorders, in particular, Alzheimer’s disease. The interaction between p75 and β-amyloid leads to neuronal death in the brain. Identification of the p75 regions involved in the development of pathology is of great importance for understanding the mechanisms of Alzheimer’s disease and for creating targeted therapeutic agents for this disorder. In the present work, immunological approaches have been used for structure-function mapping of the extracellular domain of the p75 receptor during the development of a neurodegenerative process in olfactory bulbectomized animals. The nine extracellular regions selected on the basis of X-ray structure analysis of p75 molecule hypothetically could include β-amyloid binding sites and participate in the progression of pathology. Peptides with the amino acid sequences analogous to the selected regions were synthesized. Immunization with such fragments conjugated with hemocyanin induced the formation of antipeptide antibodies in experimental animals. However, only immunization with fragment (167–176) prevented the memory loss and neuronal death in the cortex and hippocampus of bulbectomized mice. This fragment had no effect on sham-operated mice. The results indicate that fragment (167–176) of the p75 sequence deserves further research as a potential basis of the targeted immunotherapy of Alzheimer’s disease.

OBJECTIVE:Determination of antibodies to neuronal membrane proteins in the blood serum of patients is of interest for diagnosis and optimization of treatment of Alzheimer's disease (AD). Authors studied the level of antibodies to acetylcholine receptor alpha 7 protein fragment (AChR), prion protein (РrР) and glycation end-products (RAGE) as well as to intracellular proteins nucleophosmin (Nuc) and survivin (Sur) in the serum of AD patients.MATERIAL AND METHODS:Serum samples of 26 patients with probable AD and 13 healthy people were studied. Exposed sections of each protein were used for the choice of peptides for antibody visualization. ELIZA was a main method in this study.RESULTS AND CONCLUSION:Antibodies to several proteins were identified but significant differences were found only for AChR-(173-193). The results demonstrated the involvement of AChR and AChR-antibodies in the development of AD. Determination of antibodies to AChR-(173-193) may be a marker of AD and a method for specifying the diagnosis of AD.

A number of synthetic peptides corresponding to potentially important regions in the sequence of the four membrane proteins known as beta-amyloid cell receptors have been investigated on their ability to improve memory state in experimental model of Alzheimer's disease. Nine fragments repeating all the exposed nonstructural regions of the RAGE protein according to X-ray data, have been synthesized. The activity of these peptides and synthesized earlier immunoprotective fragments of other three proteins (acetylcholine receptor alpha7-type, prion protein and neurotrophin receptor p75) has been investigated under intranasal administration, without immune response to the peptide. Only one fragment RAGE (60-76) was shown to have a therapeutic activity improving the memory state of bulbectomized mice and leads to decreasing in the level of brain beta-amyloid.