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PublicationA helicase-primase drug candidate with sufficient target tissue exposure affects latent neural herpes simplex virus infections( 2021)More than 50% of the world population is chronically infected with herpesviruses. Herpes simplex virus (HSV) infections are the cause of herpes labialis (cold sores), genital herpes, and sight-impairing keratitis. Less frequently, life-threatening disseminated disease (encephalitis and generalized viremia) can also occur, mainly in immunocompromised patients and newborns. After primary infection, HSV persists for life in a latent state in trigeminal or sacral ganglia and, triggered by diverse stimuli, disease recurs in more than 30% of patients up to several times a year. Current therapy with nucleoside analogs targeting the viral polymerase is somewhat effective but limited by poor exposure in the nervous system, and latent infections are not affected by therapy. Here, we report on an inhibitor of HSV helicase-primase with potent in vitro anti-herpes activity, a different mechanism of action, a low frequency of HSV resistance, and a favorable pharmacokinetic and safety profile. Improved target tissue exposure results in superior efficacy in preventing and treating HSV infection and disease in animal models as compared to standard of care. Therapy of primary HSV infections with drug candidate IM-250 {(S)-2-(2',5'-difluoro-[1,1'-biphenyl]-4-yl)-Nmethyl-N-(4-methyl-5-(S-methylsulfon-imidoyl)thiazol-2-yl)acetamide} not only reduces the duration of disease symptoms or time to healing but also prevents recurrent disease in guinea pigs. Treatment of recurrent infections reduces the frequency of recurrences and viral shedding, and, unlike nucleosidic drugs, IM-250 remains effective for a time after cessation of treatment. Hence, IM-250 has advantages over standard-of-care therapies and represents a promising therapeutic for chronic HSV infection, including nucleoside-resistant HSV.
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PublicationPhenomenological investigation of the cytotoxic activity of fucoidan isolated from Fucus vesiculosus( 2019)
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PublicationComputationally designed bispecific MD2/CD14 binding peptides show TLR4 agonist activity( 2018)Toll-like receptor 4 plays an important role in the regulation of the innate and adaptive immune response. The majority of TLR4 activators currently in clinical use are derivatives of its prototypic ligand LPS. The discovery of innovative TLR4 activators has the potential of providing new therapeutic immunomodulators and adjuvants. We used computational design methods to predict and optimize a total of 53 cyclic and linear peptides targeting myeloid differentiation 2 (MD2) and cluster of differentiation 14 (CD14), both coreceptors of human TLR4. Activity of the designed peptides was first assessed using NF-kB reporter cell lines expressing either TLR4/MD2 or TLR4/CD14 receptors, then binding to CD14 and MD2 confirmed and quantified using MicroScale Thermophoresis. Finally, we incubated select peptides in human whole blood and observed their ability to induce cytokine production, either alone or in synergy with LPS. Our data demonstrate the advantage of computational design for the discovery of new TLR4 peptide activators with little structural resemblance to known ligands and indicate an efficient strategy with which to identify TLR4 targeting peptides that could be used as easy-to-produce alternatives to LPS-derived molecules in a variety of settings.
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PublicationAn in vitro HSV-1 reactivation model containing quiescently infected PC12 cells( 2013)Advances in the understanding of the infection and reactivation process of herpes simplex type 1 (HSV-1) are generally gained by monolayer cultures or extensive and cost-intensive animal models. So far, no reliable in vitro skin model exists either to investigate the molecular mechanisms involved in controlling latency and virus reactivation or to test pharmaceuticals. Here we demonstrate the first in vitro HSV-1 reactivation model generated by using the human keratinocyte cell line HaCaT grown on a collagen substrate containing primary human fibroblasts. We integrated the unique feature of a quiescently infected neuronal cell line, the rat pheochromocytoma line PC12, within the dermal layer of the three-dimensional skin equivalent. Transmission electron microscopy, a cell-based TCID50 assay, and polymerase chain reaction analysis were used to verify cell latency. Thereby viral DNA could be detected, whereas extracellular as well as intracellular virus activity could not be found. Further, the infected PC12 cells show no spontaneous reactivation within the in vitro skin equivalent. In order to simulate a physiologically comparable HSV-1 infection, we achieved a specific and pointed reactivation of quiescently HSV-1 infected PC12 cells by UVB irradiation at 1000 mJ/cm2.
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PublicationIntracellular action of the cytokine MIF to modulate AP-1 activity and the cell cycle through Jab1( 2000)Cytokines are multifunctional mediators that classically modulate immune activity by receptor-mediated pathways. Macrophage migration inhibitory factor (MIF) is a cytokine that has a critical role in several inflammatory conditions but that also has endocrine and enzymatic functions. The molecular targets of MIF action have so far remained unclear. Here we show that MIF specifically interacts with an intracellular protein, Jab1, which is a coactivator of AP-1 transcription that also promotes degradation of the cyclin-dependent kinase inhibitor p27(exp Kip1) (ref. 10). MIF colocalizes with Jab1 in the cytosol, and both endogenous and exogenously added MIF following endocytosis bind Jab 1. MIF inhibits Jab1- and stimulus-enhanced AP-1 activity; but does not interfere with the induction of the transcription factor NF(kappa)B. Jab1 activates c-Jun amino-terminal kinase (INK) activity and enhances endogenous phospho-c-Jun levels, and MIF inhibits these effects. MIF also antagonizes Jab1-dependent cell-cycle regulatioft by increasing p27(exp Kip1) expression through stabilization of p27(exp Kip1) protein. Consequently, Jab1-mediated rescue of fibroblasts from growth arrest is blocked by MIF Amino acids 50-65 and Cys 60 of MIF are important for Jab1 binding and modulation. We conclude that MIF may act broadly no negatively regulate Jab1-controlled pathways and that the MIF-Jab1 interaction may provide a molecular basis for key activities of MIF.
