Treatment and prophylaxis of anthrax by new neurosecretory cytokines

A FRET-based high throughput screening assay to identify inhibitors of anthrax protective antigen binding to capillary morphogenesis gene 2 protein

Anti-angiogenic therapies are effective for the treatment of cancer, a variety of ocular diseases, and have potential benefits in cardiovascular disease, arthritis, and psoriasis. We have previously shown that anthrax protective antigen (PA), a non-pathogenic component of anthrax toxin, is an inhibitor of angiogenesis, apparently as a result of interaction with the cell surface receptors capillary morphogenesis gene 2 (CMG2) protein and tumor endothelial marker 8 (TEM8). Hence, molecules that bind the anthrax toxin receptors may be effective to slow or halt pathological vascular growth. Here we describe development and testing of an effective homogeneous steady-state fluorescence resonance energy transfer (FRET) high throughput screening assay designed to identify molecules that inhibit binding of PA to CMG2. Molecules identified in the screen can serve as potential lead compounds for the development of anti-angiogenic and anti-anthrax therapies. The assay to screen for inhibitors of this protein–protein interaction is sensitive and robust, with observed Z' values as high as 0.92. Preliminary screens conducted with a library of known bioactive compounds identified tannic acid and cisplatin as inhibitors of the PA-CMG2 interaction. We have confirmed that tannic acid both binds CMG2 and has anti-endothelial properties. In contrast, cisplatin appears to inhibit PA-CMG2 interaction by binding both PA and CMG2, and observed cisplatin anti-angiogenic effects are not mediated by interaction with CMG2. This work represents the first reported high throughput screening assay targeting CMG2 to identify possible inhibitors of both angiogenesis and anthrax intoxication.

The protective and immunomodulatory effects of hypothalamic proline-rich polypeptide galarmin against methicillin-resistant Staphylococcus aureus infection in mice

The present research summarizes the protective and immunomodulatory activity of hypothalamic proline-rich polypeptide galarmin against methicillin-resistant Staphylococcus aureus (MRSA). The protective effect of galarmin was shown on MRSA-infected animals' survival and weight loss recovery. The immunological impact of galarmin was evaluated in terms of immunocompetent cell recruitment, serum immunoglobulins, complement components C3 and C4, and pro- and anti-inflammatory cytokines (IL-6, IL-8, IL-10, IL-1b, TNFa, and KC) secretion. Galarmin efficiently protects mice against lethal MRSA infection (100% of survival vs. 0% in the untreated group) when intramuscularly injected 24 h before infection and during the 1-h post-infection period at a concentration of 1 μg per mouse, while its higher concentrations (5 and 10 μg) were protective when injected in parallel to the infection process. The protective effect of galarmin was not due to a direct effect on MRSA, but should be attributed to an action on the host response to infection. Galarmin significantly increased and modulated the levels of IL-6, IL-8, IL-1b, IL-10, and KC in both peritoneal lavages and blood, leukocyte and platelet counts, lymphocytes percentage, serum IgM and IgG, and complement C3 and C4 components secretion. The experimental results allow concluding that galarmin is a powerful immunomodulatory and protective agent for the in vivo prophylaxis and treatment of MRSA-induced infection.

Antitumorigenic effect of brain proline rich polypeptide-1 in human chondrosarcoma

Proline rich polypeptide (PRP-1) produced by neurosecretory cells of the hypothalamus is one of the fragments of neurophysin-vasopressin-associated glycoprotein. The primary structure of the neuropeptide PRP-1 isolated from neurosecretory granules of bovine neurohypophysis. We investigated PRP-1 action on chondrosarcoma, the second most common malignancy in bone, which primarily affects the cartilage cells. This deadly disease does not have any effective treatment. Earlier we demonstrated MYC oncogene inactivating effect by 1 lg/ml concentration brain PRP-1 In the present study we observed reduced viable sarcoma JJ012 cell numbers in comparison with control (89% growth inhibition) when treated with low concentrations of PRP-1 (0.5–1 lg/ml). Higher concentrations did not exhibit inhibitory effect. We assume that PRP-1 in low concentration impedes cell cycle progression. The fact that low concentrations of PRP-1 abolished Myc activity prompts to think that the antitumorigenic effect of PRP-1 in low concentrations is mediated through oncogene inactivation.

Cytostatic effect of novel mTOR inhibitor, PRP-1 (galarmin) in MDA 231 (ER-) breast carcinoma cell line. PRP-1 inhibits mesenchymal tumors

Activation of the PI3K-Akt-mTOR pathway is implicated both in the establishment of tumors and as well as a target for therapy in many types of solid malignancy, its blockade represents an opportunity to improve outcomes in patients with tumors that are associated with poor prognosis. Our experimental data indicates that proline-rich polypeptide-1 (PRP-1, galarmin) is immunomodulator cytokine, produced by hypothalamic neurosecretory cells and exerts its antiproliferative effect on the tumor cells of mesenchymal origin via inhibiting mTOR kinase activity and repressing cell cycle progression. The goal of these investigations was to elucidate the antiproliferative action of PRP-1 on the breast carcinoma cell line MDA 231 (ER-) and to compare PRP-1 action previously reported on other mesenchymal tumors. These experiments confirmed maximum inhibition of cell growth at 0.5 and 1 μg/ml PRP-1 (71% and 63%, respectively) and inhibition at 10 μg/ml of 44%. There was no inhibitory effect observed on luminal T47-D (ER+) cells. Videomicroscopy results demonstrated dividing cells in the cytokine-treated MDA 231 (ER-), suggesting that the cells were not in the state of dormancy. The flow cytometry experiments confirmed that PRP-1-treated cells were accumulated in S phase. No apoptosis, caspase activation, or senescence was detected after treatment with this cytokine. Experiments with mTOR with PRP-1 (10 μg/ml) indicated statistically significant 40% inhibition of mTOR kinase activity in immunoprecipitates of the MDA 231 (ER-) cell line. PRP-1 is a novel mTOR inhibitor with strong antiproliferative action in mesenchymal tumors mostly resistant to radiation and chemotherapy.

Cytostatic effect of the hypothalamic cytokine PRP-1 is mediated by mTOR and cMyc inhibition in high grade chondrosarcoma

This study aimed to further elucidate the molecular mechanisms of antiproliferative action of proline rich polypeptide 1 (PRP-1) cytokine, produced by neurosecretory cells of the hypothalamus to be considered as alternative adjuvant therapy for metastatic chondrosarcoma, which does not respond to chemotherapy or radiation and currently without any effective treatment. Rapid cell proliferation assay of human primary cultures from high grade chondrosarcoma patients biopsies and human chondrosarcoma JJ012 cell line indicated 50 and 80% inhibition in PRP-1 treated samples correspondingly. Videomicroscopy detected that despite the treatment there are still dividing cells, meaning that cells are not in the state of dormancy, rather PRP-1 repressed the cell cycle progression, exhibited cytostatic effect. The mammalian target of rapamycin (mTOR) is an intracellular serine/threonine protein kinase that has a crucial role in a nutrient sensitive signaling pathway that regulates cell growth. Experiments with mTOR pathway after PRP-1 (10 μg/ml) treatment indicated statistically significant 30% inhibition of mTOR activity and its 56% inhibition in immunoprecipitates with PRP-1 concentrations effective for cell proliferation inhibition. Treatment with PRP- caused inhibition of mTOR and downstream target cMyc oncogenic transcription factor sufficient to trigger the cytostatic effect in high grade, but not in low grade chondrosarcomas. The fact that lower concentrations than 10 μg/ml peptide with cytostatic effect did not inhibit mTOR, but inhibited cMyc prompted us to assume that PRP-1 binds to two different receptors facilitating the antiproliferative effect.

Concepts of neuroendocrine cardiology and neuroendocrine immunology, chemistry and biology of signal molecules

Discovery of neurosecretion of cardioactive neurohormones produced by hypothalamic nuclei (NSO and NPV), as well as the biosynthesis of several immunomodulators (signal molecules of the neuroendocrine immune system of brain), deciphering of their chemical structure and study of their biological properties led to the foundation of two important trends of neurobiology: neuroendocrine immunology and cardiology. Hormone formation by atrium ganglionary nerve cells and auriculum establishment of neurohumoral interactions between hypothalamic and atrium neurosecretion indicated the existence of the system neuroendocrine hypothalamus--endocrine heart. Study of their biological properties promoted creation of powerful neurohormonal preparations for the treatment of immune, cardio-vascular, neurodegenerative, infectious and tumor diseases. Concepts suggested by us on neuroendocrine cardiology and immunology, create large perspectives for development of the theory and its implementation in medicine.

Antioxidant and electron donating function of hypothalamic polypeptides: galarmin and Gx-NH2

Chemical mechanisms of antioxidant and electron donating function of the hypothalamic proline-rich polypeptides have been clarified on the molecular level. The antioxidant-chelating property of Galarmin and Gx-NH(2) was established by their capability to inhibit copper(II) dichloride catalyzed H(2)O(2) decomposition, thus preventing formation of HO(*) and HOO(*) radicals. The antiradical activity of Galarmin and Gx-NH(2) was determined by their ability to react with 2,2-diphenyl-1-picrylhydrazyl radical applying differential pulse voltammetry and UV-Vis spectrophotometry methods. Galarmin manifest antiradical activity towards 2,2-diphenyl-1-picrylhydrazyl radical, depending on the existence of phenolic OH group in tyrosine residue at the end of the molecule. The presence of antiradical activity and reduction properties of Galarmin are confirmed by the existence of an oxidation specific peak in voltammograms made by differential pulse voltammetry at E ( composite function) = 0.795 V vs. Ag/Ag(+) aq.