[Fragment of Receptor for Advanced Glycation End Products Improves Memory State in a Model of Alzheimer's Disease].

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.

Immunization with either prion protein fragment 95-123 or the fragment-specific antibodies rescue memory loss and neurodegenerative phenotype of neurons in olfactory bulbectomized mice.

Epidemiological studies demonstrated association between head injury (HI) and the subsequent development of Alzheimer's disease (AD). Certain hallmarks of AD, e.g. amyloid-ß (Aß) containing deposits, may be found in patients following traumatic BI (TBI). Recent studies uncover the cellular prion protein, PrP(C), as a receptor for soluble polymeric forms of Aß (sAß) which are an intermediate of such deposits. We aimed to test the hypothesis that targeting of PrP(C) can prevent Aß related spatial memory deficits in olfactory bulbectomized (OBX) mice utilized here to resemble some clinical features of AD, such as increased level of Aß, memory loss and deficit of the CNS cholin- and serotonin-ergic systems. We demonstrated that immunization with the a.a. 95-123 fragment of cellular prion (PrP-I) recovered cortical and hippocampus neurons from OBX induced degeneration, rescued spatial memory loss in Morris water maze test and significantly decrease the Aß level in brain tissue of these animals. Affinity purified anti-PrP-I antibodies rescued pre-synaptic biomarker synaptophysin eliciting similar effect on memory of OBX mice, and protected hippocampal neurones from Aß25-35-induced toxicity in vitro. Immunization OBX mice with a.a. 200-213 fragment of cellular prion (PrP-II) did not reach a significance in memory protection albeit having similar to PrP-I immunization impact on Aß level in brain tissue. The observed positive effect of targeting the PrP-I by either active or passive immunization on memory of OBX mice revealed the involvement of the PrP(C) in AD-like pathology induced by olfactory bulbectomy. This OBX model may be a useful tool for mechanistic and preclinical therapeutic investigations into the association between PrP(C) and AD.

[Antibodies for detection of E/K amino acid substitution in 129 position of the survivin sequence].

Survivin is an oncofetal protein involved both in inhibiting of apoptosis and in cell cycle regulation. The functions of survivin are defined by its structural state. Due to nature polymorphism, survivin cancontain either E or K amino acid in 129 residue, and K129 is commonly acetylated. Only the protein having acetylated K129 tends to form dimeric structure. Thus, antibodies detecting the amino acid substitution can be a useful tool for structural and functional research of the protein. To obtain the antibodies specific to amino acid substitution E129/K129 peptide fragments overlapping 129 amino acid residue were synthesized, rabbits were immunized with the peptides and affinity purification of the antibodies on sepharose conjugated with the peptides was carried out. The data of ELISA and western blot showed that antibodies obtained were able to detect amino acid substitution E129/K129 in the recombinant and endogenous survivin.

[Antibodies to synthetic fragment 95-123 of the prion protein protect neurons and astrocytes from beta-amyloid toxicity].

Toxic effect of beta-amyloid on brain cells during Alzheimer's disease pathology is known to be associated with oxidative stress, intracellular Ca2+ increase in neurons and astrocytes and activation of reactive oxygen species production. Prion protein is involved in beta-amyloid toxicity. Here we investigated an effect of affinity purified antibodies to synthetic fragment 95-123 of the prion protein on beta-amyloid induced cell death, Ca(2+)-signal, reactive oxygen species production and caspase 3 activation. We have shown that antibodies to fragment 95-123 are able to protect neurons and astrocytes from beta-amyloid induced cell death with no effect on the intracellular Ca2+ concentration altered by beta-amyloid treatment. However, the antibodies significantly reduced Abeta induced reactive oxygen species production in astrocytes and decreased caspase 3 activation in neurons and astrocytes. Thus, induction of antibodies to synthetic fragment 95-123 of the prion protein provides a new approach to anti-AD vaccine design.

[Antibodies to synthetic peptides for the detection of survivin in tumor tissues].

Survivin, an endogenous protein, is a promising marker for the diagnosis of cancer. The aim of the present work was to obtain antibodies specific to survivin and capable of detecting this protein in tumor tissues. Four peptides corresponding to fragments (1-22), (54-74), (80-88)-(153-165), and (118-144) of the survivin-2B sequence were selected and synthesized. Rabbits were immunized with the synthetic peptides. It has been shown that all peptides in a free state, without conjugation with a high-molecular-weight carrier, stimulate the production of antibodies capable of binding with recombinant survivin. Antipeptide antibodies were isolated from sera and their performance in the immunohistochemical detection of survivin in human tumor tissues was studied. It was shown that only antibodies to the (80-88)-(153-165) peptide bind to the survivin present in breast and bladder tumors. The ability of antibodies to this peptide to detect survivin in tumor tissue lysates was demonstrated by immunoblotting. The part of the sequence targeted by the antibodies against the (80-88)-(153-165) peptide was localized using truncated peptide fragments.

[Antibodies to synthetic fragments of nucleophosmin for the specific detection of its monomeric and oligomeric forms].

Immunoactive fragments corresponding to the N-terminal (19-36) and C-terminal (283-294) regions of the NPM1.1 isoform of nucleophosmin and their shortened fragments were chosen and synthesized. Rabbits were immunized with free full-size peptides and their protein conjugates. Antibodies produced against the 19-36 and 283-294 peptides were purified by affinity chromatography on bromocyanogen-activated sepharose that was preliminary conjugated with the synthetic peptides. An analysis of immunoblots of lysates of the HeLa and Ramos cells demonstrated that the antibodies produced against the 19-36 peptide detected the monomeric form of nucleophosmin, whereas the antibodies against the 283-294 peptide predominantly revealed its oligomeric form. It was established by immunocytochemical analysis that the antibodies induced by the 19-36 peptide stained the nucleoplasm and perinuclear space of the cytoplasm of the HeLa and Ramos cells, but did not stain the nucleoli, while the antibodies against the 283-294 peptide stained only the nucleoli of the same cells. On the basis of these results, one could propose that the monomeric and oligomeric forms of nucleophosmin were located in the nucleoplasm and nucleoli of the examined cells, respectively. Thus, antibodies which can predominantly detect monomeric and oligomeric forms of nucleophosmin were produced for the first time. An analysis of the monomeric-oligomeric state and the location of the nucleophosmin in tumor cells could be performed using these antibodies.

[New approaches to the immunotherapy of Alzheimer's disease with the synthetic fragments of alpha7 subunit of the acetylcholine receptor].

The effect of immunization with the synthetic fragments of the alpha7 subunit of the acetylcholine nicotine receptor on the spatial memory of mice subjected to olfactory bulbectomy, which causes the development of the neuro-degenetrative disease of Alzheimer's type, was studied. Mice of the NMRI line were immunized with the KLH conjugates of two peptide fragments of the N-terminal fragment of the alpha7 subunit extraxcellular fragment, subjected to olfactory bulbectomy to cause the development of the neurodegenetrative disease of Alzheimer's type, and then the state of the spartial memory was evaluated. It was shown that 20% of bulbectomized mice immunized with the N-terminal 1-23 fragment exhibited good spatial memory after training. Immunization with the peptide construct (159-167)-(179-188) consisting of two hydrophilic exposed regions of alpha7-subunit induced good spatial memory in 50% of bulbectomized mice, while in the control group, which received only KLH, none of the animals were educated. Thus, the development of immunotherapy with peptide (159-167)-(179-188) seems to be a promising approach to prophylaxis and treatment of Alzheimer's disease.

[Antitumor immunotherapy with the use of synthetic fragments of survivin].

The endogenous protein survivin is present in tumor cells and inhibits apoptosis. The influence of vaccination of mice by survivin fragments on growth of various types of tumors was studied to examine the possibility of creation of an antitumor vaccinating agent on its basis. Two peptides corresponding to the (118-144) and (80-88)-(153-165) sequences of survivin 2B were chosen and synthesized on the basis of literature data and theoretical calculations. Their ability to stimulate antibody production in mice of the C57BL/6J line (b haplotype) and in BDF1 hybrids (b x d haplotype) was investigated. Both peptides were shown to stimulate production of antibodies that bound the recombinant survivin in the BDF1 mice. Immunization of the BDF1 and C57BL/6J mice with the recombinant survivin resulted in the formation of antibodies that reacted with the (118-144) peptide. The effect of preventive vaccination with the peptides and the recombinant protein on the dynamics of growth of several species of tumors was studied. Vaccination with the (80-88)-(153-165) peptide was found to cause an antitumor effect in BDF1 mice suffering from sarcoma S-37. Thus, the creation of an antitumor agent on the basis of this peptide is a promising area of further studies.

[Synthesis and biological properties of polysaccharide-peptide conjugates as potential antigens for a vaccine against meningococci of serogroups A and B].

A new approach to the development of a vaccine against meningococci of serogroups A and B was proposed. It involves the synthesis of conjugates of high-molecular capsule polysaccharides of the serogroup A meningococcus (PsA) with earlier synthesized protective fragments of membrane proteins from serogroup B meningococci. The conjugates were synthesized using a method that consists of the generation of aldehyde groups by oxidizing free vicinal hydroxyl groups of PsA and subsequent reaction of these groups with amino groups of the peptide. The reaction proceeds with the intermediate formation of the Schiff base, which is reduced to the stable secondary amine. The main parameters of the reaction were optimized in the synthesis of a PsA conjugate with a model peptide and methods of their characterization were developed. The reproducibility and efficiency of the synthetic procedure were demonstrated by the example of synthesis of PsA conjugates with fragments of protein PorA from the outer membrane of the serogroup B meningococcus. It was shown that, when administered without adjuvant, a conjugate of PsA with a protective peptide, which represents an exposed conserved fragment 306-332 of protein PorA, stimulates the formation of antibodies to the peptide and polysaccharide moieties of the molecule and is also capable of decreasing the degree of bacteremia in animals infected with serogroup A and serogroup B meningococci. The approach can be applied to the development of a complex vaccine for serogroup A and serogroup B meningococci.

[Synthetic fragments of the NS1 protein of the tick-borne encephalitis virus exhibiting a protective effect].

Potentially immunoactive regions of the NS1 nonstructural protein of the tick-borne encephalitis virus that can stimulate the antibody formation in vivo and protect animals from this disease were chosen on the basis of theoretical calculations. Eleven 16- to 27-aa peptides containing the chosen regions were synthesized. The ability of the free peptides (without any high-molecular-mass carrier) to stimulate the production of antipeptide antibodies in mice of three lines and ensure the formation of protective immunity was studied. Most of these peptides were shown to exhibit the immunogenic activity in a free state. Five fragments that can protect mice from the infection by a lethal dose of tick-borne encephalitis virus were found.

[Induction of antibodies to particular sites of the alpha7 subunit of the nicotinic acetylcholine receptor in mice of different lines].

Five synthetic fragments of the N-terminal domain of the alpha7 subunit of the human nicotinic acetylcholine receptor (alpha7 nAChR) that correspond to theoretically calculated B epitopes and T helper epitopes of the protein and contain from 16 to 29 amino acid residues were tested for the ability to stimulate the formation of antibodies in mice of three lines having H-2d, H-2b, and H-2k haplotypes of the major histocompatibility complex. It was shown that, in the free (unconjugated) form, all the peptides stimulate the formation of antibodies at least in one mouse line. Most of the peptides induced the formation of antibodies in BALB/c mice (haplotype H-2d); therefore, more detailed studies were carried out on these animals. The free peptides and/or their conjugates with keyhole limpet hemocyanin were demonstrated to be capable of stimulating the formation in BALB/c mice of antibodies that bind to the recombinant extracellular N-terminal domain of (alpha7 nAChRalpha). The epitope mapping of antipeptide antibodies carried out using truncated fragments helped reveal antipeptide antibodies to four regions of the alpha7 subunit: 1-23, 98-106, 159-168, and 173-188 (or 179-188).

[Peptide inhibitors of the renin-angiotensin system. 2. Polymer-bound tri-, penta- and nonapeptide inhibitors of angiotensin converting enzyme]. / Peptidinhibitoren des Renin-Angiotensin-Systems. 2. Mitteilung: Polymergebundene Tri-, Penta- und Nonapeptid-Inhibitoren des Angiotensin-Coverting-Enzyms.

Inhibitors of the angiotensin converting enzyme (ACE, EC 3.4.15.1) are important in the treatment of the high blood pressure. The therapeutically used drugs captopril, enalapril and ramipril are enzymatic stable short pseudo-peptides. They are stabilized against enzymatic degradation and therefore usefully for oral application. But for some indications e.g. post operative treatment and shock therapy well dosed infusions are needed. For this purpose we attached nona-, penta- and tripeptide inhibitors of the ACE to immunologically inert dextran polymers. The inhibitors are derived as well from the bradykinin potentiating nonapeptide BPP9 alpha (Pyr-Trp-Pro-Arg-Pro-Gln-Ile-Pro-Pro) and the bradykinin potentiating pentapeptide BPP5 alpha (Pyr-Lys-Trp-Ala-Pro), both originally isolated from snake venoms, as from acylated tripeptides with the structure Acyl-AA1-Arg-Pro. We estimated the influence on the biological activity of two different linkers to the dextran polymers. The coupling to the polymer was achieved on the one hand via the aldehyd moiety (DAD-AK) and on the other hand by the carboxyl residue (KMD). In the case of DAD-AK-polymers the condensation of the peptides was performed by the N-hydroxysuccinimide ester of the polymer. Because of the instability of the KMD-OSU in this case water soluble carbodiimides are used. The polymer bound peptides inhibit the isolated ACE, but in the most cases with a reduced activity. Only the tripeptide DPhe-Arg-Pro has a enhanced activity in the polymer bound state. The polymer bound inhibitors show a prolongated action on normotensive rats by intravenous application.(ABSTRACT TRUNCATED AT 250 WORDS)

[Synthesis and effect of affinity-labeled analogs and partial sequences of the bradykinin potentiating nonapeptide BPP9 alpha (teprotide)]. / Synthese und Wirkung affinitätsmarkierter Analoga und Partialsequenzen des Bradykinin potenzierenden Nonapeptides BPP9 alpha (Teprotide).

Affinity labeled analogues and partial sequences of the bradykinin potentiating nonapeptide BPP9 alpha inhibit the BPP9 alpha induced potentiation of the bradykinin action on the isolated guinea pig ileum. The labeled nonapeptides are more active than the labeled partial sequences. The inhibition of the potentiating action of BPP9 alpha demonstrates, that the influence on bradykinin action is not only a result of the inhibition of peptidyl dipeptide hydrolase.

[Synthesis and analysis of conformationally restricted analogs of peptide inhibitors of the angiotensin-converting enzyme]. / Sintez i issledovanie konformatsionno ogranichennykh analogov peptidnykh ingibitorov angiotenzinprevrashchaiushchego fermenta.

To investigate conformations of peptide inhibitors of the angiotensin-converting enzyme in the enzyme-inhibitor complex, the synthesis, studies of inhibitory activity, and conformational calculations of analogues of bradykinin-potentiating peptides with N-methylalanine or D-alanine in place of L-proline or L-alanine residues have been carried out. All the analogues showed a sharp decrease of inhibitory activity in comparison with the natural peptides, that might be considered as an indirect confirmation of the earlier proposed "conformation of inhibition" of the above-mentioned peptides.

[Synthesis and biological activity of analogs of a nonapeptide inhibitor of peptidyldipeptidase]. / Sintez i biologicheskaia aktivnost' analogov nonapeptidnogo ingibitora peptidildipeptidazy.

The synthesis of 5 analogues of the effective inhibitor of peptidyl dipeptidase, teprotide, has been carried out. The inhibitory and bradykinin-potentiating activity of these compounds has been assayed. N-Terminal pyroglutamic acid and positive charge of arginine in position 4 were found to be essential for biological activity of the inhibitor.

[Synthesis of angiotensin converting enzyme inhibitors containing residues of substituted quinolines and a study of their biological activity]. / Sintez ingibitorov angiotenzinprevrashchaiushchego fermenta, soderzhashch ostatki zameshchennykh khinolinov, i issledovanie ikh biologicheskoi aktivnosti.

Inhibitors of the angiotensin-converting enzyme were synthesized by substituting N-and C-terminal amino acid residues of tripeptide Bz-Phe-Ala-Pro by the residues of 8-methoxy-5-sulphoquinoline and carboxy-1,2,3,4-tetrahydroquinoline, respectively, and their in vivo and in vitro biological activity was determined. The enzyme's S2' site proved to be non specific to the position of the carboxylic group in the C-terminal heterocyclic part of the inhibitor molecule. Introducing a modified quinoline residue into the N-terminal part of the inhibitor does not increase its specific interaction with the hydrophobic pocket of the angiotensin-converting enzyme.

[Peptides--inhibitors of carboxycathepsin (peptidyl-dipeptidase A) and their role in clinical medicine]. / Peptidy-ingibitory karpoksikatepsina (peptidil-dipeptidazy A) i ikh znachenie dlia klinicheskoi meditsiny.

Properties of the carboxycathepsin inhibitors teprotide, captopryl, enalacryl are considered. Presence of low molecular thermo- and acid stable carboxycathepsin inhibitors of peptide nature in blood serum and lymphocytes is discussed.

Mechanisms of defense formation against meningococcal infection in mice immunized with synthetic peptides.

Immunization of mice with synthetic peptide fragments of conservative sites of meningococcal outer membrane proteins led to defense formation against infection with virulent serogroup A and B Meningococci. The role of cellular immunity in the formation of defense against meningococcal infection after immunization with the peptides and the possibility of stimulating lymphocyte population with these peptides were demonstrated.

[A substrate inhibitor analysis of the urinary excretion of tissue and plasma kallikreins in patients with chronic glomerulonephritis]. / Substratno-ingibitornyi analiz mochevoi ékskretsii tkanevogo i plazmennogo kallikreinov u bol'nykh khronicheskim glomerulonefritom.

The usage of substrate inhibitor analysis made it possible to estimate the levels of excretion of plasma proteinases, including plasma kallikrein in the urinary DValLeuArgpNA (S-2266)- and DProPheArgpNA (S-2302)-amidase activity in patients with latent and nephrotic types of chronic glomerulonephritis (CGN). The soya bean trypsin inhibitor, an inhibitor of plasma kallikrein and other plasma proteinases, such as that of the blood coagulative factors XIa and XIIa, and the high selective plasma kallikrein inhibitor DPhePheArgCH2Cl were used as those differentiating kallikreins of tissue and plasma origin. The S-2266 and S-2302-amidase activity of the urine from healthy subjects was shown to be determined by only tissue (renal) kallikrein. The urine from the patients with a latent CGN type displayed the activity of plasma proteinases, but plasma kallikrein made no significant contribution to the urine amidase activity in these patients. With a nephrotic CGN type, great quantities of trypsin-like proteinases were secreted from the plasma through the glomerular filter into the urine, the proportion of plasma kallikrein in the urinary S-2266 and S-2302-amidase activities being approximately 27%. The compensatory and pathogenetic role of plasma kallikrein is discussed if there is lower excretion of tissue (renal) kallikrein in CGN with the nephrotic syndrome.