[Amyloid-like fibrils forming and fibroblasts destruction in Tenon's capsule in progressive myopia as a result of pigment epithelium derived factor resistance to restricted proteolysis].

We have shown previously the presence of full length (50 kD) and truncated proteolytic form (45 kD) of pigment epithelium derived factor (PEDF) in the eye Tenon's capsule in progressive myopia. The full length PEDF is prevalent in myopia that correlates with breach in collagen fibrils forming. Immunohistochemical analysis of Tenon's capsule with polyclonal antibodies to PEDF revealed PEDF in control group being exclusively inside fibroblasts, whereas in myopia, PEDF was distributed extracellularly as halo around blasted fibroblasts. By means of atomic force microscopy and immunodot analysis with anti amyloid fibrils antibodies the ability was studied of recombinant PEDF fragments to form fibrils. Only full length PEDF was shown to form amyloid like fibril structures, but not the truncated form. Accumulation offibrils results in fibroblasts destruction and might be the cause of changes in biochemical and morphological structure of Tenon's capsule observed in myopia.

[Haponin (eIF1AD) interacts with glyceraldehyde 3-phosphate dehydrogenase in the CHO-K1 cell line].

Haponin (HLDF-alike protein) was previously identified from the human promyelocytic leukemia HL-60 cell line. For the functional study of this protein, we obtained recombinant haponin with an N-terminal hexahistidine tag using a baculovirus expression system. Antibodies against 6xHis-haponin were produced, and the expression of endogenous haponin was demonstrated in mammalian cell lines of different origin. Using affinity chromatography and immunoprecipitation methods, we have shown that in CHO-K1 cells haponin interacts with glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which is one of the vital glycolytic enzymes with a diverse set of noncanonical functions.

[Antitumor properties of a liposomal form of a differentiation factor HLDF fragment in cultured cells].

Cytotoxic properties of a liposomal form of the HLDF6 hexapeptide, representing an HL-60 cell differentiation factor fragment, have been studied on a murine primary lymphosarcoma cell culture. It is established that the liposomal HLDF6 peptide is capable of inhibiting proliferation and enhancing death of the cells of both LS and RLS lymphosarcoma strains distinguished by their sensitivity to cytostatic agents. The effect of the preparation is determined by its antiproliferative and apoptogenic actions on the cells. Free HLDF6 peptide showed a lower cytotoxic activity with respect to the tumor cells as compared to the liposomal preparation.

[STAT1: a many-sided transcription factor].

Cell homeostasis is regulated by numerous signaling proteins. Their main task is to process extracellular signals and activate the intracellular cascades of reactions that lead to the modulation of gene activity. One of the important signaling systems is the STAT family, which is comprised of seven members. Various STATs operate as effective transcription factors delivering cytokine and growth factor signals to the nucleus. The first found and most studied member of this family is STAT1. This review summarizes modern data on the role of STAT1 in the maintenance of cellular homeostasis, and special attention is paid to this protein in the proliferation and apoptosis of immune system cell processes. It is shown that disturbances in the functionality of this molecule might contribute to oncogenesis.

[Investigation of antitumor activity of the hexamer fraction of HLDF-6 peptide as a differentiation factor in hemoblastoma-bearing mice].

A study of antitumor properties of HLDF-6 was carried out in DBA/2 mice with transplantable ascites lympholeukemia P-388 as well as in tumor cell culture. Immunomodulating characteristics were evaluated. Five-fold administration of HLDF-6 peptide to tumor-bearing mice inhibited tumor growth thus extending survival. As a result metabolic activity decreased which was followed by longer survival of lympholeukemia P-388 cells and enhanced cytological effect of peritoneal macrophages on tumor cells of the same strain.

[The proapoptotic factor HLDF in the normal, hyperplastic and neoplastic endometrium].

Antibodies to the factor HLDF are shown to be specific markers of apoptosis and permit the estimation of the rate of programmed cell death in the course of a normal menstrual cycle and in pathologic endometrial processes. HLDF expression in the epitheliocytic cytoplasm makes it possible to evaluate apoptosis at early stages, before the emergence of the first morphological signs and after apoptotic body formation. The study shows increased apoptotic processes at the end of a normal menstrual cycle and during neoplastic cell transformation. Antibodies to the HLDF factor may be used as a new immunohistochemical marker for the differential diagnosis of benign and malignant endometrial processes.

[Identification and expression of haponin, a new protein from HL-60 cells].

We found a new protein haponin (an HLDF-alike protein) in promyelocyte HL-60 cells that is immunoreactive to polyclonal antibodies against HLDFbeta. Determination of the partial primary structure of the protein allowed us to reveal an immunogenic peptide of haponin and, on the basis of the amino acid sequence of this peptide, the degenerate primers were synthesized, which enabled us to clone the full-size cDNA of haponin. The stable heterologous expression of this cDNA in E. coli cells (Rosetta strain) was obtained. Preparations of natural and recombinant proteins exhibited antigenic cross-reactivity to polyclonal antibodies against this peptide.

[Neuroprotective effect of the hexapeptide HLDF-6 on neurons of rat hippocampus on the model of Alzheimer's disease in vivo and in vitro].

The neuroprotective effect of Thr-Gly-Glu-Asn-His-Arg hexapeptide (HLDF-6), a biologically active fragment of the differentiation factor of human leukemia cells (HLDF), was demonstrated on models of Alzheimer's disease in vivo and in vitro. The syndromes of this pathology were induced in male rats by administration of the peptide corresponding to the 25-35 sequence of beta-amyloid peptide (25-35) and ibotenic acid into the hippocampus. HLDF-6 prevented loss of long-term memory and decrease in the orientation-investigation activity of these animals and significantly decreased the number of pyknotic neurons in the CA1 area of the hippocampus. This peptide also exerts a protective effect in vitro on the primary cultures of neurons of the hippocampus and cerebellum of rats under conditions of the beta-amyloid toxicity. An increase in the dihydrotestosterone (DHT) content was demonstrated in the blood plasma of rats with the syndrome of Alzheimer's disease and in the medium of the culture of hippocampus neurons in the presence of the Abeta(25-35) peptide. HLDF-6 inhibited this increase in both cases. A probable mechanism of the neuroprotective effect of HLDF-6 was suggested as being connected to its possible effect on both the biosynthesis and the metabolism of sex steroid hormones.

[Synthesis and structure-function study of artificial nucleases on the basis of hemin conjugates with peptide fragments of cell differentiation factor HLDF].

A series of octa-hexapeptide fragments of HLDF and their conjugates with hemin were obtained by solid phase peptide synthesis. A relationship between the structure and the nuclease activity of the compounds was established. The effect of various factors (medium pH, the presence of metal ions, complexons, reducers, and buffer composition) on DNA destruction with hemin peptides was studied. Preliminary information confirming an oxidative mechanism of this process was obtained. The cleavage of plasmid DNA under the action of hemin peptides was studied by the methods of electron microscopy, gel electrophoresis, and atomic force microscopy.

[L-Glutamic acid modulates the cytotoxic effect of tumor necrosis factor in the HL-60 cell line].

L-Glutamic acid was shown to increase the stability of cells of the HL-60 line of human promyelocyte leukemia to the cytotoxic action of tumor necrosis factor alpha (TNF-alpha) due to the inhibition of apoptotic and NF-kappaB-activating cascades induced by this cytokine. At the same time, L-glutamic acid increases the TNF-alpha-mediated differentiating signal and the accompanying enhancement of the phosphatidylinositol-specific phospholipase C activity. Therefore, it is a promising agent for the reduction of total toxicity and inflammatory processes during treatment with TNF-alpha. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 6; see also http://www.maik.ru.

[Precursors of HLDF differentiation factor and ribosomal protein RPS21 have a common N-terminal sequence]. / Predshestvennik faktora differentsirovki HLDP i ribosomnyi belok RPS21 imeiut obshchuiu N-kontsevuiu posledovatel'nost'.

The mature differentiation factor HLDF, isolated from culture fluid, comprises 54 aa, whereas the open reading frame of mRNA encodes a 97-aa protein. We presumed that the protein translation begins from the first ATG codon, whose environment mostly meets the requirements for the initiation point. Two more ATG triplets are localized in positions 48-50 and 100-102, i.e., in the area preceding the cDNA fragment that encodes the N-terminal fragment of the mature protein. The mRNAs of HLDF and the S21 ribosomal protein have previously been shown to be highly homologous, and, therefore, their differences appear to be derived from two point deletions in the cDNA of the HLDF-encoding sequence (a G residue in position 112 and a C residue in position 224). As a result, the mature differentiation factor and RPS21 may be the products of translation from different open reading frames, the differentiation factor may be synthesized in the cell as a precursor, and its N-terminal sequence may be identical to that of RPS21. To test this hypothesis, we prepared recombinant RPS21 and the polyclonal antibodies to HLDF, full-size RPS21, and the C-terminal RPS21 peptide. Immunochemical staining by specially produced antibodies of native HL-60 cells and the same cells brought into apoptosis or differentiation confirmed that the precursor of the differentiation factor and the ribosomal S21 protein have a common N-terminal sequence and different cellular localizations. Neither an intron-containing gene nor a pseudogene with the nucleotide sequence corresponding to the HLDF cDNA was detected in the human genome or in the HL-60 cell line genome. On the basis of these facts, we propose a hypothesis of the molecular mechanism of the HLDF mRNA biosynthesis by means of posttranslational modifications of pre-mRNA of RPS21. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2004, vol. 30, no. 2; see also http://www.maik.ru.

[Protein HLDF and antibodies to it as molecular pathogenetic factors and new markers of acute cerebral blood circulation disturbances]. / Belok HLDF i antitela k nemu kak molekuliarnye patogeneticheskie faktory i novye markery ostrykh narushenii mozgovogo krovoobrashcheniia.

Clinic-experimental complex investigation and ELISA determination of protein HLDF as also primary antibodies (Abs) to HLDF values in blood and cerebro-spinal fluid (CSF) of patients with hypertensive crises and acute aterotrombotic ischemic stroke were performed. Statistically improved difference in serum HLDF and Abs content in examined patients in comparison with age-matched controls as also significant intergroup's differences in protein and Abs dynamic content were determined. Correlation between content and dynamics of investigated factors in CSF and blood serum with determined clinical and instrumental parameters was revealed. Pathogenetic and prognostic significance of revealed changes in molecular factors was viewed.

[An artificial protein, possessing biological activity of HL-60 human promyelocytic leukemia differentiation factor]. / Iskusstvennyi belok, obladaiushchii biologicheskoi aktivnost'iu faktora differentsirovki kletok linii HL-60 promielotsitarnogo leikoza cheloveka.

The ABB-df artificial protein was prepared by inserting the TGENHR biologically active peptide corresponding to the 41-46 sequence of the differentiation factor for the HL-60 cell line of the human promyelocyte leukemia into the N-terminus of the polypeptide chain of albebetin, an artificial protein with the preset structure. The ABB-df protein was found to induce the differentiation of HL-60 cells and to inhibit their proliferation; its efficiency was almost the same as that of the starting peptide. According to CD spectroscopy, the inclusion of the peptide fragment into albebetin exerts virtually no effect on the regular secondary structure of albebetin.

[Effect of homologous peptides of differentiation factors HLDF and PEDF on preimplantation development of mice in vitro]. / Vliianie gomologichnykh peptidov factorov differentsirovki HLDF i PEDF na doimplantatsionnoe razvitie myshei in vitro.

We studied the effect of synthetic peptides PEDF-6 and HLDF-6 on preimplantation development of mouse embryos in vitro. PEDF-6 peptide corresponds to fragment 351-356 and of pigment epithelium-derived differentiation factor (PEDF), while HLDF-6 peptide corresponds to fragment 84-89 of differentiation factor HLDF isolated from HL-60 cell line. Despite high homology, these peptides had different effects on the early development. PEDF-6 had no effect on the cleavage of 2-4-cell embryos but decelerated blastocyst formation from such embryos and disturbed their structure. In the presence of HLDF-6 the blastomeres divided more actively as compared to the control and a higher number of embryos developed to the blastocyst stage. The effects of both peptides were stage-specific: the affect the embryos at early cleavage stages and, apparently, determine their further development at that moment although do not directly affect formation of the blastocysts.

[Synthetic peptides -- analogs of biologically active fragment of the differentiation factor from HL-60 cells show radioprotective and adaptogenic activities]. / Sinteticheskie peptidy -- analogi biologicheski aktivnogo fragmenta faktora differentsirovki kletok HL-60 proiavliaiut radioprotektornuiu i adaptogennuiu aktivnost'.

It was shown that the addition of synthetic six-membered peptide (HLDF-6) and its Tyr-analog (HLDF-Y) to cultural medium significantly increased the survival of cells HL-60, treated by cold shock. The prophylactic administration of HDLF-Y (1 mg/kg, 4 hours prior to applied actions) decreased the response of hypothalamushypophysis-adrenal glands system and sympathicoadrenal system of rat males on supercooling and also increased the resistance of mouse males to supercooling and X-irradiation. In the experiences with females HDLF-Y did not show the similar biological activity.

[Nuclease activity of human interleukin-10]. / Nukleaznaia aktivnost' interleikina-10 cheloveka.

The nuclease activity of human interleukin-10, an immunosuppressive cytokine, was predicted on the basis of structural homology between the 97-105 sequence of human interleukin-10 and the DNA/RNA-hydrolyzing fragment of the endogenous differentiation factor for the HL-60 line of human promyelocyte leukemia cells. The human recombinant interleukin-10 was shown to cleave all forms of plasmid DNA. The role of interleukin-10 in the apoptosis induction in monocytic cells was hypothesized. The English version of the paper.

[Expression of the apoptosis inhibitor soluble Fas antigen in patients with malignant and benign bone neoplasms]. / Ekspressiia ingibitora apoptoza--rastvorimogo Fas-antigena u bol'nykh so zlokachestvennymi i dobrokachestvennymi novoobrazovaniiami kostei.

This paper presents results of comparative enzyme immunoassay of soluble serum Fas antigen (sFas) in 98 patients with benign and malignant bone tumors, 15 patients with mechanical bone traumas, and 60 normal individuals of compatible age. The prevalence and concentration of sFas were significantly greater in patients with bone tumors than in normal donors and patients with mechanical bone traumas. The association of sFas with the pathogenesis of primary bone tumors is discussed in the paper.

[Biological role of a neurotrophic factor fragment from pigment epithelium: structure-functional homology with a differentiation factor for the HL-60 cell line]. / Biologicheskaia rol' fragmenta neirotrfnogo faktor iz pigmentnogo épiteliia: strukturno-funktsional'naia gomologiia s faktorom differentsirovki kletok linii HL-60.

It was shown that the full-size neurotrophic factor from pigment epithelium (PEDF) induces the cell differentiation of the human promyelocyte leukemia cell line HL-60. A structural analysis of PEDF revealed in its C-terminal region a six-membered peptide fragment PEDF-(352-357) (PEDF-6) whose sequence is highly homologous to the 41-46 fragment of the active site of the human leukocyte differentiation factor HLDF (HLDF-6). The biological effect of PEDF and synthetic peptides PEDF-6 and HLDF-6 on the HL-60 cells and the early gastrula ectoderm of Xenopus laevis embryos was studied. On the basis of the structural and functional homologies of HLDF, PEDF, and their homologous peptides and the computer models of the spatial structures of the full-size PEDF and the PEDF with the C-terminal fragment split off tby the cleavage of the Leu380-Thr381 bond in the serpin loop, a hypothesis on the functional role of the serpin loop in PEDF was put forward.

[Biologically active fragment of the differentiation factor from HL-60 cell line. Identification and properties]. / Biologicheski aktivnyi fragment faktora differentsirovki kletok linii HL-60. Identifikatsiia i svoistva.

Six-membered peptide fragment TGENHR (HLDF-6) was identified in the HL-60 cell culture of human promyelocyte leukemia treated with retinoic acid when studying the differentiation factor HLDF of this cell line. HLDF-6 retains the ability of the full-size factor to induce the differentiation and arrest the proliferation of the starting HL-60 cells. It was shown that the synthetic peptide HLDF-6 has no specific receptors on the surface of the HL-60 cells but can affect the binding of interleukin IL-1 beta, a cytokine involved in proliferation, to the cell surface. It was found on a model of transplantable NSO myeloma that HLDF-6 has an antitumor activity.

[The endogenous differentiation factor of the HL-60 cells shows a nuclease activity]. / Endogennyi faktor differentsirovki kletok linii HL-60 obladaet nukleaznoi aktivnost'iu.

A structural homology between the endogenous differentiation factor of the HL-60 cell line of promyelocyte leukemia (HLDF) and several DNA/RNA-binding and DNA/RNA-hydrolyzing proteins was revealed, and expression of the hldf gene in prokaryotic systems was studied. On the basis of these experiments, the amino acid sequence of an 8-membered fragment of HLDF with potential nuclease activity was identified. The synthetic octapeptide RRWHRLKE was shown to be capable of the cleavage of RNA, linear DNA from phage lambda, and all forms of plasmid DNA. We established that treatment of the HL-60 cell culture with this peptide (10(-6) M) results in an increase in the number of apoptotic cells and suggested that HLDF is involved in processes of apoptosis.