Peculiarities of immunocorrective effects of the bone marrow regulatory peptides (myelopeptides)

Myelopeptides (MPs) are low-molecular-weight immunoregulatory peptides of bone marrow origin. The peculiarities of their immunoregulatory effects are demonstrated with two of the six synthesized MPs, MP-1 (Phe-Leu-Gly-Phe-Pro-Thr) and MP-2 (Leu-Val-Val-Tyr-Pro-Trp). It is shown that MP action is directed to the damaged links of immunity. MP-1 enhances a decreased level of antibody production in cyclophosphamide (Cy)-treated mice, but does not influence the antibody formation in normal animals. MP-2 inhibits the tumor growth more in a tumor-bearing organism as the tumor size gets larger, insofar as MP-2 antitumor effect is concerned, by its ability to recover functional activity of T lymphocytes suppressed by tumor products. Selective immunocorrective effects of MPs are based on ligand-receptor interactions. Using FITC-labeled MP-1 and [3H]-labeled MP-2, specific binding of these peptides with appropriate cell populations is shown. The cytofluorimetric analysis revealed a target cell for MP-1--CD4+ T lymphocyte (T helper). The data obtained suggest that MPs are endogenic immunoregulators which participate in the maintenance of immune homeostasis.     

Heme-peptide/protein interactions: the binding of heme octa and undecapeptides, and microperoxidase-8 and -11, to human serum albumin

The interaction of the heme octa (MP-8) and undeca (MP-11) peptides derived from cytochrome c with lipidated human serum albumin (HSA) has been investigated in aqueous solution. It is demonstrated that complex formation occurs in each case with a 1:1 stoichiometry. CN- binding has been used to investigate the accessibility of the heme in each complex by comparison with CN- interaction with methemalbumin. A preliminary study of the kinetics of the Fe3+MP-8/11 human serumalbumin (HSA) interaction demonstrates a clear ligand-size-related effect on mechanism of interaction--an ad hoc explanation of which is given in terms of HSA existing as two nonconverting conformers in solution.     

Isolation and partial characterization of membrane protein constituents of human neutrophil receptors for chemotactic formylmethionyl peptides

Plasma membranes of human neutrophils were solubilized in buffer containing a nonionic detergent and applied to a formylmethionylleucylphenylalanine (fMet-Leu-Phe)-Sepharose column that was washed and eluted with the chemotactic peptide fMet-Leu-Phe. Analysis of the eluate by filtration on Bio-Gel P150 in sodium dodecyl sulfate (NaDodSO4) buffer and by NaDodSO4-polyacrylamide gel electrophoresis revealed three predominant membrane proteins of approximate molecular weight 94 000 (MP-1), 68 000 (MP-2), and 40 000 (MP-3), of which MP-2 accounted for 74--93% of the total protein. Purified MP-1 and MP-2 contained an above average content of hydrophobic amino acids, while MP-2 and MP-3 had an above average content of acid and/or amide amino acids and a below average content of basic amino acids. MP-2 and MP-3, but not MP-1, bound [3H]fMet-Leu-Phe in equilibrium dialysis chambers. Both MP-2 and MP-3 exhibited high-affinity sites with a valence of 0.2--0.3 and mean KA values of 9 x 10(8) and 2 x 10(7) M-1, respectively, and low-affinity sites with a valence of 0.3--0.5 and mean KA values of 3 x 10(7) and 2 x 10(6) M-1 (n = 3). The specificity of the binding of fMet-Leu-Phe was suggested by the failure of MP-2 and MP-3 to bind lipid chemotactic factors and to adhere to a Sepaharose column to which had been coupled chemotactic fragments of the fifth component of complement. A series of synthetic formylmethionyl peptides exhibited the same rank order of potency as inhibitors of the binding of [3H]fMet-Leu-Phe by MP-2 and as stimuli of neutrophil chemotaxis. Membrane proteins isolated by fMet-Leu-Phe-Sepharose affinity chromatography may represent constituents of specific human neutrophil receptors for chemotactic peptides.     

Characterization of cDNAs, mRNAs, and proteins related to human liver microsomal cytochrome P-450 (S)-mephenytoin 4'-hydroxylase

A cytochrome P-450 (P-450) multigene family codes for several related human liver enzymes, including the P-450 responsible for (S)-mephenytoin 4'-hydroxylation. This enzyme activity has previously been shown to be associated with a genetic polymorphism. Genomic (Southern) blot analysis using non-overlapping 5' and 3' portions of a cDNA clone suggests that approximately seven related sequences are present in this gene family. In this study four cDNA clones, all nearly full-length, were isolated from a bacteriophage lambda gt11 library prepared from a single human liver. These clones can be grouped into two categories that are approximately 85% identical at the level of DNA sequence. The cDNA clones in one category (MP-4, MP-8) both match the N-terminal sequences of the P-450MP-1 and P-450MP-2 proteins, which had previously been shown to be catalytically active in (S)-mephenytoin 4'-hydroxylation. These two cDNAs, MP-4 and MP-8, differ in only two bases in the coding region but are quite distinct in their 3' noncoding regions. Another protein (P-450MP-3) was isolated on the basis of its immunochemical similarity to P-450MP-1 but was found to be catalytically inactive; amino acid sequencing of tryptic peptides of P-450MP-3 showed a correspondence to the second category of cDNA clones (MP-12, MP-20), which differ from each other in only four (nonsilent) base changes. Oligonucleotides specific for the two groups of cDNA clones were used as probes of human liver mRNAs--individual liver samples examined expressed both types of mRNAs but no correlation was observed between the abundance levels of any mRNA and catalytic activity. Further, oligonucleotide probes indicated that mRNAs corresponding to both the MP-4 and MP-8 clones were apparently present in individual liver samples. A monoclonal antibody was isolated that recognized P-450MP-1 but not P-450MP-2 or P-450MP-3; the amount of protein detected by the antibody in different liver samples was not correlated with the mephenytoin 4'-hydroxylase activity. These results indicate that several closely related P-450 genes are all expressed in individual human livers. The MP-4/MP-8 gene products are proposed to be the ones most likely involved in mephenytoin 4'-hydroxylation, and much of the variation in catalytic activity among individuals is not a result of differences in levels of P-450MP-1 or mRNA but may be due to base differences in the structural gene(s).     

Helix-stabilizing effects of the pentapeptide KIFMK and its related peptides on the sodium channel inactivation gate peptides.

We have previously found by NMR and CD spectroscopic studies that the helical content of the sodium channel inactivation gate-related peptide (Ac-GGQDIFMTEEQK-NH2; MP-1A) in 80% trifluoroethanol solutions was increased by adding a pentapeptide, KIFMK. In order to study in further detail whether the presence of the IFM motif and the two lysine residues is a prerequisite for stabilizing the helical conformation, we examined interactions between various oligopeptides (RIFMR, KIFMTK, KIQMK, KAFAK, KIIIK) and MP-1A and its related peptides; that is, MP-2A in which Phe was replaced by Gln, MP-1MMA in which Thr was replaced by Met, MP-1TA in which Thr was removed from MP-1A, and MP-1A' in which L-Phe was replaced by D-Phe. It was found that the IFM motif was absolutely necessary in both the oligopeptide and the inactivation gate peptide. This finding means that hydrophobic interactions are operative between KIFMK and MP-1A. In contrast, KIFMK destabilized the helical structure of MP-1MMA, MP-1TA, and MP-1A', showing that the conformation around the IFM motif in the inactivation gate peptides is an important factor. It was concluded that the IFM motif and the two Lys residues are a prerequisite for effectively stabilizing the alpha-helix of MP-1A.     

Myelopeptide MP-5 and fluorescent derivatives: Synthesis and biological activity

The Val-Val-Tyr-Pro-Asp bone marrow peptide (MP-5) and its analogue (MP-5-Lys) were synthesized. Fluorescent derivatives, Ftc-MP-5 and MP-5-Lys(Ftc), were prepared. The iological activity of MP-5 and MP-5-Lys was studied in vitro and in vivo. The MP-5 peptide caused 60–84% inhibition of growth of the following mouse cancers: lymphatic leukemia P388, melanoma B-16, and cervical carcinoma CUC-5. These peptides also restored functional activity of T-lymphocytes that was inhibited by metabolic products of the HL-60 leukemic cell line. MP-5-Lys(Ftc) was shown to preserve the functional properties of MP-5 towards T-lymphocytes, but Ftc-MP-5 was practically inactive.     

Structural study of the sodium channel inactivation gate peptide including an isoleucine-phenylalanine-methionine motif and its analogous peptide (phenylalanine/glutamine) in trifluoroethanol solutions and SDS micelles.

In order to gain insight into the gating mechanisms of Na+ channels, in particular their inactivation mechanisms, we studied the structures of the Na+ channel inactivation gate related peptide which includes the IFM (Ile-Phe-Met) motif (Ac-KKKFGGQDIFMTEEQKK-NH2; K1480-K1496 in rat brain type-IIA Na+ channels, MP-3A) and its F/Q(Gln) substituted one (MP-4A) in trifluoroethanol (TFE) solutions and sodium dodecyl sulfate (SDS) micelles using circular dichroism (CD) and 1H-NMR spectroscopies. Based on observed nuclear Overhauser effect constraints, three-dimensional structures of MP-3A and MP-4A were determined using simulated annealing molecular dynamics/ energy minimization calculations. In TFE solutions, no appreciable differences in the structure were observed using either CD or NMR spectra. In SDS micelles, however, the two peptides exhibited definitely different structures from each other. It was found that in MP-3A, residues 11488 and T1491 were spatially proximate with each other owing to hydrogen bonding between the amide proton of 11488 and the hydroxyl oxygen atom of T1491, whereas in MP-4A, F/Q substitution separated them owing to conformational changes. The solvent-accessible surfaces calculated for the structures of MP-3A and MP-4A showed that the former has a smoother interaction surface to the hydrophobic docking site than the latter. In conclusion, the conformational changes, as well as decreased hydrophobicity around the IFM motif owing to the F/Q mutation, may be one reason why F1489Q mutated channels cannot inactivate almost completely.     

Synthesis and properties of the retro-analogue of myelopeptide MP-2

The bone marrow myelopeptide MP-2 (Leu-Val-Val-Tyr-Pro-Trp), exhibiting antitumor activity, and its retro-analogue (Trp-Pro-Tyr-Val-Val-Leu) were synthesized, and their properties were studied. The in vitro and in vivo activities of retro-MP-2 were comparable with those of MP-2. Both peptides equally restored the functional activity of T-lymphocytes inhibited by toxins released by HL-60 cells and inhibited by 70-82% the growth of various types of transplantable solid tumors: Ca-755 adenocarcinoma of the mammary gland, Lewis adenocarcinoma of the lung, and S180 sarcoma. The positions and intensities of the Cotton effects in CD spectra of the MP-2 peptide and its retro-analogue in various solvents are almost indistinguishable. The positions of extrema and integral intensities of the amide I and amide A bands in IR spectra of both peptides were practically identical. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.     

Spatial structure of myelopeptides: I. Conformational analysis of MP-1, MP-2, and MP-3

Theoretical conformational analysis was used to study the spatial structure and conformational properties of myelopeptides, bone-marrow peptide mediators. The low-energy conformations of three hexapeptides MP-1 (Phe-Leu-Gly-Phe-Pro-Thr), MP-2 (Leu-Val-Val-Tyr-Pro-Trp), and MP-3 (Leu-Val-Cys-Tyr-Pro-Gln) were found, the values of dihedral angles of the backbone and side chains of the amino acid residues constituting these peptides were determined, and the energies of intra- and interresidual interactions were estimated.     

Effect of the SH-group of myelopeptide MP-3 on its macrophage-stimulating activity]

Peptide Leu-Val-Cys-Tyr-Pro-Gln, identical to the bone marrow peptide MP-3, and its Val3 and Ser3 analogs, lacking SH-group, were synthesized by conventional methods of peptide chemistry in solution and, along with the MP-3 S-S-dimerization product, were studied with respect to their effect on the macrophage phagocytic activity. It was shown that the activity was only enhanced by peptide MP-3, which demonstrated the essential role of the SH-group in this function. The dimer analog of MP-3, unlike dimer analogs of other monocysteine-containing peptides, glutathione and HP5b, did not exhibit the inhibitory effect.     

Effect of the SH Group of Myelopeptide MP-3 on Its Macrophage Stimulating Activity

Peptide Leu-Val-Cys-Tyr-Pro-Gln, identical to the bone marrow peptide MP-3, and its Val³and Ser³analogs, lacking SH group, were synthesized by conventional methods of peptide chemistry in solution and, along with the MP-3 S–S-dimerization product, were studied with respect to their effect on the macrophage phagocytic activity. It was shown that the activity was only enhanced by peptide MP-3, which demonstrated the essential role of the SH group in this function. The dimer analog of MP-3, unlike dimer analogs of other monocycteine-containing peptides, glutathione and HP5b, did not exhibit the inhibitory effect.     

Myelopeptides: Bone marrow regulatory mediators

Bone marrow cells of various animal species and men produce a group of bioregulatory peptides called myelopeptides (MPs). A highly purified MP fraction and some individual molecules have been isolated from the supernatant of porcine bone marrow cell cultures by reverse phase chromatography.MPs have a wide spectrum of functional activities: immunoregulatory, differentiating and opiate-like. They evoke 2–5-fold stimulation of antibody production to various antigens. They correct some immune defects in MRL/lpr mice with spontaneous autoimmune disorders that results in 2-fold prolongation of the life span of these mice. MPs influence the differentiation of bone marrow and peripheral blood cells derived from healthy and leukemic donors. They induce terminal differentiation in the leukemic human HL-60 cell line. MPs also show an effect on pain sensitivity.A new immunocorrective drug Myelopid has been developed on the basis of MP mixtures. This drug is effectively used in Russia both in medicine and veterinary practice for prophylaxis and treatment of diseases accompanied by immunodeficiency.Two individual MPs were isolated and identified: Phe-Leu-Gly-Phe-Pro-Thr (MP-1) and Leu-Val-Val-Tyr-Pro-Trp (MP-2). MP-1 displays immunoregulatory activity; MP-2 abolishes the inhibitory effect of leukemic cells on T-lymphocyte functional activity.MPs seem to provide not only immunoregulation but also to participate in complex interactions between different systems in the organism.     

Synthesis and Properties of the <Emphasis Type="Italic">retro</Emphasis>-Analogue of Myelopeptide MP-2

The bone marrow myelopeptide MP-2 (Leu-Val-Val-Tyr-Pro-Trp), exhibiting antitumor activity, and its retro-analogue (Trp-Pro-Tyr-Val-Val-Leu) were synthesized, and their properties were studied. The in vitro and in vivo activities of retro-MP-2 were comparable with those of MP-2. Both peptides equally restored the functional activity of T-lymphocytes inhibited by toxins released by HL-60 cells and inhibited by 70–82% the growth of various types of transplantable solid tumors: Ca-755 adenocarcinoma of the mammary gland, Lewis adenocarcinoma of the lung, and S180 sarcoma. The positions and intensities of the Cotton effects in CD spectra of the MP-2 peptide and its retro-analogue in various solvents are almost indistinguishable. The positions of extrema and integral intensities of the amide I and amide A bands in IR spectra of both peptides were practically identical.__________Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 3, 2005, pp. 239–244.Original Russian Text Copyright © 2005 by Fonina, Ovchinnikov, Gur’yanov, Sychev, Belevskaya, Treshchalina.     

1H-NMR and circular dichroism spectroscopic studies on changes in secondary structures of the sodium channel inactivation gate peptides as caused by the pentapeptide KIFMK.

The pentapeptide KIFMK, which contains three clustered hydrophobic amino acid residues of isoleucine, phenylalanine, and methionine (IFM) in the sodium channel inactivation gate on the cytoplasmic linker between domains III and IV (III-IV linker), is known to restore fast inactivation to the mutant sodium channels having a defective inactivation gate or to accelerate the inactivation of the wild-type sodium channels. To investigate the docking site of KIFMK and to clarify the mechanisms for restoring the fast inactivation, we have studied the interactions between KIFMK and the fragment peptide in the III-IV linker GGQDIFMTEEQK (MP-1A; G1484-K1495 in rat brain IIA) by one- and two-dimensional (1)H-NMR and circular dichroism (CD) spectroscopies. KIFMK was found to increase the helical content of MP-1A in 80% trifluoroethanol (TFE) solution by approximately 11%. A pentapeptide, KIFMT, which can restore inactivation but less effectively than KIFMK, also increased the helical content of MP-1A, but to a lesser extent ( approximately 6%) than did KIFMK. In contrast, KDIFMTK, which is ineffective in restoring inactivation, decreased the helical content ( approximately -4%). Furthermore, we studied the interactions between KIFMK and modified peptides from MP-1A, that is, MP-1NA (D1487N), MP-1QEA (E1492Q), or MP-1EQA (E1493Q). The KIFMK was found to increase the helical content of MP-1EQA to an extent nearly identical to that of MP-1A, whereas it was found to decrease those of MP-1NA and MP-1QEA. These findings mean that KIFMK, by allowing each of the Lys residues to interact with D1487 and E1492, respectively, stabilized the helical structure of the III-IV linker around the IFM residues. This helix-stabilizing effect of KIFMK on the III-IV linker may restore and/or accelerate fast inactivation to the sodium channels having a defective inactivation gate or to wild-type sodium channels.     

Kinetics of heme octapeptide (microperoxidase-8; MP-8) formation studied by high-pressure liquid chromatography (HPLC) monitoring of the peptic and tryptic hydrolysis of horse heart cytochrome-c

The kinetics of the sequential peptic and tryptic hydrolysis of cytochrome-c to give the heme-peptides microperoxidase-11 (MP-11) and -8 (MP-8), respectively, has been investigated by high performance liquid chromatography (HPLC), and we demonstrate that MP-8 can be prepared from cytochrome-c to the point of lyophilization within 4 hr.     

Spatial structure of myelopeptides: I. conformational analysis of MP-1, MP-2, and MP-3

Theoretical conformational analysis was used to study the spatial structure and conformational properties of myelopeptides, bone-marrow peptide mediators. The low-energy conformations of three hexapeptides MP-1 (Phe-Leu-Gly-Phe-Pro-Thr), MP-2 (Leu-Val-Val-Tyr-Pro-Trp), and MP-3 (Leu-Val-Cys-Tyr-Pro-Gln) were found, the values of dihedral angles of the backbone and side chains of the amino acid residues con-stituting these peptides were determined, and the energies of intra- and interresidual interactions were estimated.Translated from Bioorganicheskaya Khimiya, Vol. 31, No. 1, 2005, pp. 31–38.Original Russian Text Copyright © 2005 by Akhmedov, Ismailova, Abbasli, Akhmedov, Godjaev.     

Effect of the mineral-ammonia preparations MP-15 and MP-7 on nitrogen metabolism in cows

It has been studied how MP-15 and MP-7 preparations fed on to lactating cows affect the indices of acid-base equilibrium of their blood, nitrogen metabolism, milk yield and milk quality. It is shown that feeding on MP-15 and MP-7 preparations to cows of test groups has no negative effect on the acid-base equilibrium indices, decreases the ammonia concentration by 38.5 and 54.9%, respectively, increases the glutamine content in blood by 23.5 and 29.4%, respectively, does not affect the pyruvate, glutamate, oxaloacetate concentration and alanine-transaminase activity, increases the average daily milk yields by 2.1 and 2.3 l, respectively, and does not deteriorate the composition and physicochemical indices of milk quality.     

Effect of myelopeptide-1 on the functional activity of phagocytes from mice treated with cyclophosphane

The capacity of the bone marrow-derived myelopeptide-1 (MP-1) to affect in vivo and in vitro the functional activity of phagocytes of intact mice and mice treated with a cytostatic agent (cyclophosphane) has been studied. It was found that MP-1 produces a correcting effect on the functional activity of bone marrow and peripheral blood phagocytes. An optimal scheme of the injection of MP-1 to mice with the cyclophosphane-induced immunodeficiency was developed, which provides a maximum immunocorrecting action. MP-1 had the most pronounced effect on the quantitative characteristics and the functional activity of phagocytes of different localization when introduced prior to the cytostatic; under these conditions, the pep tide affects peripheral blood neutrophils. The results obtained enable one to consider MP-1 as a preparation protecting the peripheral blood phagocytes from the damaging action of cyclophosphane.     

抗HIV-1活性的大环多胺类化合物与RNA的识别作用及其对细胞凋亡的影响(英)

研究了具有抗HIV-1活性的大环多胺类化合物与RNA的识别作用，以及其对cos-7细胞凋亡的影响，以进一步探讨其抗HIV-1的作用机理.实验采用琼脂糖凝胶电泳方法, 观察化合物与RNA的识别作用；通过流式细胞计数法探讨其对cos-7细胞凋亡的影响；运用计算机分子模型, 从理论上Docking计算化合物与TAR RNA结合的可能性.结果表明, 大环多胺类化合物MP-1、MP-2和MP-3不仅具有断裂RNA的作用，并可抑制Tat-RNA的相互作用, 还可影响cos-7细胞亚二倍体的含量; 理论化学计算数据与实验结果基本一致.这一结果提示化合物的抗HIV-1活性可能通过作用于病毒基因组RNA而发挥作用，是多靶作用的结果.     

A new endogenous differentiating factor (myelopeptide-4) for myeloid cells

Along with known lymphokines involved in the regulation of hematopoiesis, a new differentiating factor (myelopeptide-4, MP-4) for myeloid cells was found. The peptide (Phe-Arg-Pro-Arg-Ile-Met-Thr-Pro) originally isolated from the culture medium of porcine bone marrow cell culture was examined for its ability to induce differentiation in two human myeloid leukemia cell lines, HL-60 and K-562. Agents with well-known differentiation-inducing activity, such as phorbol myristate acetate, dimethylsulfoxide and the lymphokines were used as a reference. It has been shown that MP-4 significantly influences the integral characteristics of metabolism, expression of surface antigens and morphology of these cells. It decreased the level of chromosomal DNA synthesis and, in parallel, increased the total protein synthesis in both HL-60 and K-562 cells. MP-4 induced the expression of CD14 monocyte-specific surface antigen and the appearance of mature monocytes/macrophages in HL-60 cell cultures. There was a good correlation of cell metabolic/morphological changes and the CD14 marker expression for HL-60 cells. A similar phenomenon was observed in K-562 cells treated with MP-4 when the levels of hemoglobin synthesis were detected in their cytoplasm. Thus, we consider MP-4 as a new endogenous differentiating factor for myeloid cells.