Novel Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa) from Natural Product Anabaenopeptin

Halland, Nis; Brönstrup, Mark; Czech, Jörg; Czechtizky, Werngard; Evers, Andreas; Follmann, Markus; Kohlmann, Markus; Schiell, Matthias; Kurz, Michael; Schreuder, Herman; Kallus, Christopher

doi:10.1021/jm501840b

Cited by 36 publications

(36 citation statements)

References 31 publications

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“…Anabaenopeptins are a highly diverse family of cyclic heptapeptides characterized by an ureidolinkage connecting the side chain amino acids to D-lysine. Members of this family are potent protease inhibitors and have served as lead products for the design of inhibitors against carboxypeptidase TAFIa (24). Although anabaenopeptin production has been principally demonstrated for N. punctiforme PCC 73102, no larger amount could be obtained for further characterization (18).…”

Section: Discussionmentioning

confidence: 99%

High-Density Cultivation of Terrestrial Nostoc Strains Leads to Reprogramming of Secondary Metabolome

Guljamow

Kreische

Ishida

et al. 2017

Appl Environ Microbiol

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Terrestrial symbiotic cyanobacteria of the genus Nostoc exhibit a large potential for the production of bioactive natural products of the nonribosomal peptide, polyketide, and ribosomal peptide classes, and yet most of the biosynthetic gene clusters are silent under conventional cultivation conditions. In the present study, we utilized a high-density cultivation approach recently developed for phototrophic bacteria to rapidly generate biomass of the filamentous bacteria up to a density of 400 g (wet weight)/liter. Unexpectedly, integrated transcriptional and metabolomics studies uncovered a major reprogramming of the secondary metabolome of two Nostoc strains at high culture density and a governing effect of extracellular signals in this process. The holistic approach enabled capturing and structural elucidation of novel variants of anabaenopeptin, including one congener with potent allelopathic activity against a strain isolated from the same habitat. The study provides a snapshot on the role of cell-type-specific expression for the formation of natural products in cyanobacteria.IMPORTANCE Terrestrial filamentous cyanobacteria are a largely untapped source of small-molecule natural products. Exploitation of the phototrophic organisms is hampered by their slow growth and the requirement of photobioreactors. The present study not only demonstrates the suitability of a recently developed two-tier vessel cultivation approach for the rapid generation of biomass of Nostoc strains but also demonstrates a pronounced upregulation of high value natural products at ultrahigh culture densities. The study provides new guidelines for high-throughput screening and exploitation of small-molecule natural products and can facilitate the discovery new bioactive products from terrestrial cyanobacteria.

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Section: Discussionmentioning

confidence: 99%

High-Density Cultivation of Terrestrial Nostoc Strains Leads to Reprogramming of Secondary Metabolome

Guljamow

Kreische

Ishida

et al. 2017

Appl Environ Microbiol

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“…Characteristic for many anabaenopeptins is the inhibition of zinc-containing metalloexopeptidases such as carboxypeptidase A (CPA) and B (CPB) [ 14 , 25 ]. In experiments driven by pharmacological interests, anabaenopeptins have been shown to inhibit also carboxypeptidase U [ 26 ] and carboxypeptidase TAFIa, the thrombin activatable fibrinolysis inhibitor, important in the coagulation-fibrinolysis system [ 27 ]. Only a few studies so far have demonstrated activity of anabaenopeptins towards serine endopeptidases such as elastase, trypsin and chymotrypsin [ 28 , 29 , 30 ].…”

Section: Introductionmentioning

confidence: 99%

Structures and Activity of New Anabaenopeptins Produced by Baltic Sea Cyanobacteria

et al. 2015

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Anabaenopeptins, bioactive cyclic hexapeptides, were isolated by preparative reversed-phase high performance liquid chromatography from an extract of Baltic Sea cyanobacterial bloom material composed of Nodularia spumigena (50%), Aphanizomenon flos-aquae (40%) and Dolichospermum spp. (10%). Five new anabaenopeptins and nine previously known anabaenopeptins were isolated, and their putative structures were determined by tandem mass spectrometry. The activity of the peptides against carboxypeptidase A and protein phosphatase 1 as well as chymotrypsin, trypsin and thrombin was tested. All anabaenopeptins inhibited carboxypeptidase A (apart from one anabaenopeptin variant) and protein phosphatase 1 with varying potency, but no inhibition against chymotrypsin, trypsin and thrombin was observed.

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“…Data collection was performed at the Swiss Light Source. Data processing and structure refinement was performed as described (25). The coordinates and structures factors of the crystal structure were submitted to the Protein Data Bank (code 5CGJ).…”

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confidence: 99%

Characterization of RA839, a Noncovalent Small Molecule Binder to Keap1 and Selective Activator of Nrf2 Signaling

Winkel

Engel

Margerie

et al. 2015

Journal of Biological Chemistry

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The activation of the transcription factor NF-E2-related factor 2 (Nrf2) maintains cellular homeostasis in response to oxidative stress by the regulation of multiple cytoprotective genes. Without stressors, the activity of Nrf2 is inhibited by its interaction with the Keap1 (kelch-like ECH-associated protein 1). Here, we describe (3S)-1-[4-[(2,3,5,6-tetramethylphenyl) sulfonylamino]-1-naphthyl]pyrrolidine-3-carboxylic acid (RA839), a small molecule that binds noncovalently to the Nrf2-interacting kelch domain of Keap1 with a K d of ϳ6 M, as demonstrated by x-ray co-crystallization and isothermal titration calorimetry. Whole genome DNA arrays showed that at 10 M RA839 significantly regulated 105 probe sets in bone marrow-derived macrophages. Canonical pathway mapping of these probe sets revealed an activation of pathways linked with Nrf2 signaling. These pathways were also activated after the activation of Nrf2 by the silencing of Keap1 expression. RA839 regulated only two genes in Nrf2 knock-out macrophages. Similar to the activation of Nrf2 by either silencing of Keap1 expression or by the reactive compound 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid methyl ester (CDDO-Me), RA839 prevented the induction of both inducible nitric-oxide synthase expression and nitric oxide release in response to lipopolysaccharides in macrophages. In mice, RA839 acutely induced Nrf2 target gene expression in liver. RA839 is a selective inhibitor of the Keap1/Nrf2 interaction and a useful tool compound to study the biology of Nrf2.The transcription factor NF-E2-related factor 2 (Nrf2) 2 is a promising target for the treatment of oxidative and inflammatory stress-related disorders, such as neurodegenerative and microvascular diseases (1-5). Nrf2 regulates the expression of several cytoprotective anti-oxidative and anti-inflammatory proteins by binding to the cis-acting antioxidant response element (ARE) within gene promoters. Nrf2 itself is regulated by the kelch-like ECH-associated protein 1 (Keap1), which is a substrate recognition subunit for a cullin3-based ubiquitin E3 ligase and functions as a sensor for oxidative and electrophilic stress. Structural elements of the Keap1 protein include the C-terminal Nrf2-binding kelch domain, the intervening region, and the broad complex-Tramtrack-Bric-a-Brac domain. Keap1 binds as a dimer via its two Kelch domains to one molecule of Nrf2, specifically to the high affinity ETGE and the low affinity DLG motives at the N terminus of Nrf2. Without stressors, this leads to the ubiquitinylation and subsequent proteolytic degradation of the transcription factor. In the presence of oxidative or electrophilic stress, cysteine residues within the intervening region and broad complex-Tramtrack-Bric-a-Brac domain of Keap1 become modified. According to the hinge and latch model, this weakens the interaction between Keap1 and the DLG motif of Nrf2 but does not lead to a release of Nrf2 (6, 7). The conformation cycling model postulates a stabilization of the Keap1/Nrf2 interaction by the Keap1 modifica...

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Novel Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa) from Natural Product Anabaenopeptin

Cited by 36 publications

References 31 publications

High-Density Cultivation of Terrestrial Nostoc Strains Leads to Reprogramming of Secondary Metabolome

High-Density Cultivation of Terrestrial Nostoc Strains Leads to Reprogramming of Secondary Metabolome

Structures and Activity of New Anabaenopeptins Produced by Baltic Sea Cyanobacteria

Characterization of RA839, a Noncovalent Small Molecule Binder to Keap1 and Selective Activator of Nrf2 Signaling

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