Why are Behçet's disease patients always exhausted?

OBJECTIVES: Patients with Behçet's disease (BD) constantly complain of fatigue and many have problems with poor sleep. This ultimately has a major impact on all aspects of normal living. To attempt to understand this, Artificial Intelligence (AI) was used to identify potential biomarkers. These were alpha-melanocyte stimulating hormone (α-MSH), vasoactive intestinal peptide (VIP) and some inflammatory cytokines. We assessed the association of fatigue, quality of sleep and disease activity with circulating concentration of α-MSH, VIP and inflammatory cytokines. METHODS: There were 127 participants, 97 BD patients, and 30 healthy controls (HC). All completed the Multi-Dimensional Assessment of Fatigue questionnaire (MAF) and the Pittsburgh Sleep Quality Index (PSQI) on the day of their clinical assessment. Enzyme-linked immunosorbent assays (ELISA) were used to evaluate the serum concentrations of α-MSH, VIP and cytokines (IL-1ß, IL-6, IL-10, and TNF-α). RESULTS: 64% of BD patients experienced high fatigue scores, and 63% had poor quality of sleep. When BD and HC were compared the MAF and PSQI scores as well as the serum concentrations of α-MSH, VIP, and IL-6 were significantly higher in BD (p values were: 0.001, 0.001, 0.001, 0.004 and 0.036, respectively). Both α-MSH and IL-6 had significant impact on MAF and PSQI. Interestingly, VIP had a significant influence on PSQI and disease activity, but not on MAF. CONCLUSIONS: A better understanding of these complex clinical and biochemical interactions between α-MSH, VIP and IL-6 might lead to the development of novel approaches to manage fatigue and sleep disorders as well as disease activity in BD patients.

Augmentation of the effects of vasoactive intestinal peptide aerosol on pulmonary hypertension via coapplication of a neutral endopeptidase 24.11 inhibitor.

A deficiency of the pulmonary vasodilative vasoactive intestinal peptide (VIP) has been suggested to be involved in the pathophysiology of pulmonary hypertension (PH). Supplementation of VIP as an aerosol is hampered by the fact that it is rapidly inactivated by neutral endopeptidases (NEP) located on the lung surface. Coapplication of thiorphan, an NEP 24.11 inhibitor, could augment the biological effects of inhaled VIP alone. A stable pulmonary vasoconstriction with a threefold increase of pulmonary artery pressure was established by application the thromboxane mimetic U46619 in the isolated rabbit lung model. VIP and thiorphan were either applied intravascularly or as an aerosol. VIP caused a significant pulmonary vasodilation either during intravascular application or inhalation. These effects were of short duration. Thiorphan application had no effects on pulmonary vasoconstriction per se but significantly augmented the effects of VIP aerosol. Thiorphan, not only augmented the maximum hemodynamic effects of VIP aerosol, but also led to a significant prolongation of these effects. VIP causes pulmonary vasodilation in a model of acute experimental PH. The hemodynamic effects of VIP aerosol can be significantly augmented via coapplication of an NEP inhibitor.

Graph theory enables drug repurposing--how a mathematical model can drive the discovery of hidden mechanisms of action.

We introduce a methodology to efficiently exploit natural-language expressed biomedical knowledge for repurposing existing drugs towards diseases for which they were not initially intended. Leveraging on developments in Computational Linguistics and Graph Theory, a methodology is defined to build a graph representation of knowledge, which is automatically analysed to discover hidden relations between any drug and any disease: these relations are specific paths among the biomedical entities of the graph, representing possible Modes of Action for any given pharmacological compound. We propose a measure for the likeliness of these paths based on a stochastic process on the graph. This measure depends on the abundance of indirect paths between a peptide and a disease, rather than solely on the strength of the shortest path connecting them. We provide real-world examples, showing how the method successfully retrieves known pathophysiological Mode of Action and finds new ones by meaningfully selecting and aggregating contributions from known bio-molecular interactions. Applications of this methodology are presented, and prove the efficacy of the method for selecting drugs as treatment options for rare diseases.

New furin inhibitors based on weakly basic amidinohydrazones.

A novel series of amidinohydrazone-derived furin inhibitors was prepared; the most potent compounds 17 and 21 inhibit furin with K(i) values of 0.46 and 0.59µM, respectively. In contrast to inhibitor 17, which still contains a guanidino residue, compound 21 possesses only weakly basic amidinohydrazone groups.

Inhaled vasoactive intestinal peptide exerts immunoregulatory effects in sarcoidosis.

RATIONALE: Previous studies suggest an important immunoregulatory role of vasoactive intestinal peptide (VIP) in experimental models of chronic noninfectious inflammation. Sarcoidosis is characterized by noncaseating epitheloid cell granulomas, where excessive tumor necrosis factor-alpha production by pulmonary macrophages plays a critical role in granuloma formation and disease progression, which may lead to fatal organ dysfunction. OBJECTIVES: To test whether inhaled VIP has an immunoregulatory role. Sarcoid alveolitis was used as a prototype of immune-mediated chronic lung inflammation. METHODS: In an open clinical phase II study, we treated 20 patients with histologically proved sarcoidosis and active disease with nebulized VIP for 4 weeks. MEASUREMENTS AND MAIN RESULTS: VIP inhalation was safe, well-tolerated, and significantly reduced the production of tumor necrosis factor-alpha by cells isolated from bronchoalveolar lavage fluids of these patients. VIP treatment significantly increased the numbers of bronchoalveolar lavage CD4(+)CD127(-)CD25(+) T cells, which showed regulatory activities on conventional effector T cells. In vitro experiments demonstrated the capacity of VIP to convert naive CD4(+)CD25(-) T cells into CD4(+)CD25(+)FoxP3(+) regulatory T cells, suggesting the generation of peripheral regulatory T cells by VIP treatment. CONCLUSIONS: This study is the first to show the immunoregulatory effect of VIP in humans, and supports the notion of inhaled VIP as an attractive future therapy to dampen exaggerated immune responses in lung disorders. Thus, the inhalation of neuropeptides may be developed into a new therapeutic principle for chronic inflammatory lung disorders in humans.

Preserved pulmonary vasodilative properties of aerosolized brain natriuretic peptide.

INTRODUCTION: Inhalation of vasoactive substances is an effective treatment of pulmonary hypertension. The B-type natriuretic peptide (BNP) leads to relaxation of smooth muscle cells, caused by an increased formation of cyclic guanosine monophosphate (cGMP). The biologic activity of BNP using an inhalative approach has not been addressed. METHODS: In order to assess the vasorelaxing capacity of exogenous BNP in the isolated ventilated and buffer perfused rabbit lung model, a stable pulmonary vasoconstriction was established by either the application of endothelin-1 or the thromboxane A(2) mimetic U46619. This was followed by an intravascular or aerosol application of BNP. CGMP was measured in the recirculating buffer fluid using a radioimmunoassay technique. RESULTS: During a stable plateau of U46619 induced pulmonary vasoconstriction (mean pulmonary artery pressure, PAP 25.5+/-0.23 mmHg), the intravascular administration of BNP induced a rapid vasodilation (mean PAP 18.13+/-0.95 mmHg, p<0.001). This vasodilation was dose dependent and was paralleled by a 6-fold increase of cGMP. When BNP was aerosolized, pulmonary vasoconstriction was also significantly alleviated in the U46619 model (mean PAP 22+/-2.1 mmHg) and during endothelin-1 induced vasoconstriction (mean PAP 17.1+/-2.47 mmHg). Correspondingly, inhalation caused a significant augmentation of cGMP levels was. CONCLUSION: The vasodilative capability of BNP as an indicator of the biologic activity of this peptide is preserved during its aerosolization. Presumably these vascular actions are caused at least in part by an increased availability of cGMP.

The guanylhydrazone CNI-1493: an inhibitor with dual activity against malaria-inhibition of host cell pro-inflammatory cytokine release and parasitic deoxyhypusine synthase.

Malaria is still a major cause of death in the tropics. There is an urgent need for new anti-malarial drugs because drug-resistant plasmodia frequently occur. Over recent years, we elucidated the biosynthesis of hypusine, a novel amino acid contained in eukaryotic initiation factor 5A (eIF-5A) in Plasmodium. Hypusine biosynthesis involves catalysis of deoxyhypusine synthase (DHS) in the first step of post-translational modification. In a screen for new inhibitors of purified plasmodium DHS, CNI-1493, a novel selective pro-inflammatory cytokine inhibitor used in clinical phase II for the treatment of Crohn's disease, inhibited the enzyme of the parasite 3-fold at a concentration of 2 microM. In vitro experiments with 200 microM CNI-1493 in Plasmodium-infected erythrocytes, which lack nuclei and DHS protein, showed a parasite clearance within 2 days. This can presumably be attributed to an anti-proliferating effect because of the inhibition of DHS by the parasite. The determined IC50 of CNI-1493 was 135.79 microM after 72 h. In vivo application of this substance in Plasmodium berghei ANKA-infected C57BL/6 mice significantly reduced parasitemia after dosage of 1 mg/kg or 4 mg/kg/body weight and prevented death of mice with cerebral malaria. This effect was paralleled by a decrease in serum TNF levels of the mice. We suggest that the new mechanism of CNI-1493 is caused by a decrease in modified eIF-5A biosynthesis with a downstream effect on the TNF synthesis of the host. From the current data, we consider CNI-1493 to be a promising drug for anti-malarial therapy because of its combined action, i.e., the decrease in eIF-5A biosynthesis of the parasite and host cell TNF biosynthesis.

Inhibition of multidrug-resistant HIV-1 by interference with cellular S-adenosylmethionine decarboxylase activity.

S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in polyamine biosynthesis, can be specifically inhibited by the experimental drug SAM486A. The pharmaceutical interference with SAMDC activity results in the depletion of the intracellular pool of spermidine and spermine. In particular, low spermidine levels compromise hypusine modification and, thereby, activation of eukaryotic initiation factor 5A (eIF-5A), which is a cellular cofactor of the essential human immunodeficiency virus type 1 (HIV-1) regulatory protein Rev. In the present study, we show that SAM486A efficiently suppresses HIV-1 replication, including the replication of viruses that are resistant to multiple reverse transcriptase and protease inhibitors. At drug concentrations that efficiently inhibit the formation of progeny viruses, no toxic effects of SAM486A on cellular metabolism are observed. It is demonstrated that the antiretroviral effect of SAM486A is based on the fact that Rev activity is severely compromised in drug-treated cells. Thus, inhibition of cellular SAMDC activity may provide a novel strategy to achieve suppression of otherwise drug-resistant viruses.

Identification of cellular deoxyhypusine synthase as a novel target for antiretroviral therapy.

The introduction of highly active antiretroviral therapy (HAART) has significantly decreased morbidity and mortality among patients infected with HIV-1. However, HIV-1 can acquire resistance against all currently available antiretroviral drugs targeting viral reverse transcriptase, protease, and gp41. Moreover, in a growing number of patients, the development of multidrug-resistant viruses compromises HAART efficacy and limits therapeutic options. Therefore, it is an ongoing task to develop new drugs and to identify new targets for antiretroviral therapy. Here, we identified the guanylhydrazone CNI-1493 as an efficient inhibitor of human deoxyhypusine synthase (DHS). By inhibiting DHS, this compound suppresses hypusine formation and, thereby, activation of eukaryotic initiation factor 5A (eIF-5A), a cellular cofactor of the HIV-1 Rev regulatory protein. We demonstrate that inhibition of DHS by CNI-1493 or RNA interference efficiently suppressed the retroviral replication cycle in cell culture and primary cells. We show that CNI-1493 inhibits replication of macrophage- and T cell-tropic laboratory strains, clinical isolates, and viral strains with high-level resistance to inhibitors of viral protease and reverse transcriptase. Moreover, no measurable drug-induced adverse effects on cell cycle transition, apoptosis, and general cytotoxicity were observed. Therefore, human DHS represents a novel and promising drug target for the development of advanced antiretroviral therapies, particularly for the inhibition of multidrug-resistant viruses.

Screening assay for the identification of deoxyhypusine synthase inhibitors.

The 1st step in the posttranslational hypusine [N(epsilon)-(4-amino-2-hydroxybutyl)lysine] modification of eukaryotic translation initiation factor 5A (eIF5A) is catalyzed by deoxyhypusine synthase (DHS). The eIF5A intermediate is subsequently hydroxylated by deoxyhypusine hydroxylase (DHH), thereby converting the eIF5A precursor into a biologically active protein. Depletion of eIF5A causes inhibition of cell growth, and the identification of eIF5A as a cofactor of the HIV Rev protein turns this host protein and therefore DHS into an interesting target for drugs against abnormal cell growth and/or HIV replication. The authors developed a 96-well format DHS assay applicable for the screening of DHS inhibitors. Using this assay, they demonstrate DHS inhibition by AXD455 (Semapimod, CNI-1493). This assay represents a powerful tool for the identification of new DHS inhibitors with potency against cancer and HIV.

Activation of human mast cells through stem cell factor receptor (KIT) is associated with expression of bcl-2.

BACKGROUND: Mast cells (MCs) are multifunctional effector cells of the immune system. These cells originate from pluripotent hemopoietic progenitors. In contrast to basophils and other leukocytes, MCs exhibit a remarkably long life span (years) in vivo. Although a role for stem cell factor (SCF) and SCF receptor (KIT) in long-term survival of MCs has been proposed, the underlying biochemical mechanisms remain unknown. MATERIALS AND METHODS: We have examined expression of 'survival-related' molecules of the bcl-2 family including bcl-2 and bcl-x(L), in primary human MCs and the human MC line HMC-1. Primary MCs were isolated from dispersed lung tissue by cell sorting using an antibody against KIT. mRNA expression was analyzed by RT-PCR and Northern blotting. RESULTS: As assessed by RT-PCR, purified unstimulated lung MCs (>98% pure) exhibited KIT- and bcl-x(L) mRNA, but did not express bcl-2 mRNA. However, exposure of lung MCS to SCF (100 ng/ml) for 8 h resulted in expression of bcl-2 mRNA. Corresponding results were obtained by immunocytochemistry. In fact, exposure of MC to SCF resulted in expression of the bcl-2 protein whereas unstimulated MCs displayed only the bcl-x(L) protein without expressing the bcl-2 protein. The human MC leukemia cell line HMC-1, which contains a mutated and intrinsically activated SCF receptor, showed constitutive expression of both bcl-2 and bcl-x(L) at the mRNA and protein level. CONCLUSION: Our data show that human MCs can express members of the bcl-2 family. It is hypothesized that bcl-x(L) plays a role in KIT-independent growth of MCs, whereas bcl-2 may be involved in KIT-dependent functions of MCs.