Two Antagonistic MALT1 Auto-Cleavage Mechanisms Reveal a Role for TRAF6 to Unleash MALT1 Activation.

The paracaspase MALT1 has arginine-directed proteolytic activity triggered by engagement of immune receptors. Recruitment of MALT1 into activation complexes is required for MALT1 proteolytic function. Here, co-expression of MALT1 in HEK293 cells, either with activated CARD11 and BCL10 or with TRAF6, was used to explore the mechanism of MALT1 activation at the molecular level. This work identified a prominent self-cleavage site of MALT1 isoform A (MALT1A) at R781 (R770 in MALT1B) and revealed that TRAF6 can activate MALT1 independently of the CBM. Intramolecular cleavage at R781/R770 removes a C-terminal TRAF6-binding site in both MALT1 isoforms, leaving MALT1B devoid of the two key interaction sites with TRAF6. A previously identified auto-proteolysis site of MALT1 at R149 leads to deletion of the death-domain, thereby abolishing interaction with BCL10. By using MALT1 isoforms and cleaved fragments thereof, as well as TRAF6 WT and mutant forms, this work shows that TRAF6 induces N-terminal auto-proteolytic cleavage of MALT1 at R149 and accelerates MALT1 protein turnover. The MALT1 fragment generated by N-terminal self-cleavage at R149 was labile and displayed enhanced signaling properties that required an intact K644 residue, previously shown to be a site for mono-ubiquitination of MALT1. Conversely, C-terminal self-cleavage at R781/R770 hampered the ability for self-cleavage at R149 and stabilized MALT1 by hindering interaction with TRAF6. C-terminal self-cleavage had limited impact on MALT1A but severely reduced MALT1B proteolytic and signaling functions. It also abrogated NF-κB activation by N-terminally cleaved MALT1A. Altogether, this study provides further insights into mechanisms that regulate the scaffolding and activation cycle of MALT1. It also emphasizes the reduced functional capacity of MALT1B as compared to MALT1A

Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionation

10 páginas, 7 figuras.Increasing resistance towards anthelmintic drugs has necessitated the search for alternative treatments for the control of gastrointestinal nematode parasites. Animals fed on chicory (Cichorium intybus L.), a temperate (pasture) crop, have reduced parasite burdens, hence making C. intybus a potentially useful source for novel anthelmintic compounds or a diet-based preventive/therapeutic option. Here, we utilized in vitro bioassays with the parasitic nematode Ascaris suum and molecular networking techniques with five chicory cultivars to identify putative active compounds. Network analysis predicted sesquiterpene lactones (SL) as the most likely group of anthelmintic compounds. Further bioassay-guided fractionation supported these predictions, and isolation of pure compounds demonstrated that the SL 8-deoxylactucin (8-DOL) is the compound most strongly associated with anti-parasitic activity. Furthermore, we showed that 8-DOL acts in a synergistic combination with other SL to exert the anti-parasitic effects. Finally, we established that chicory-derived extracts also showed activity against two ruminant nematodes (Teladorsagia circumcincta and Cooperia oncophora) in in vitro assays. Collectively, our results confirm the anti-parasitic activity of chicory against a range of nematodes, and pave the way for targeted extraction of active compounds or selective breeding of specific cultivars to optimize its future use in human and veterinary medicine.We are very grateful for the guidance and support by Dr. Thomas Ostenfeld Larsen and Christopher Phippen, Technical University of Denmark, Natural product discovery, and the laboratory assistance of Mette Schjelde, University of Copenhagen. This work was funded by the Danish Council for Independent Research (Grant DFF–6111-00394). Fractionation and purification of compounds were further supported by the Green Development and Demonstration Program (GUDP) (Project No. 34009-17-1220). MPE was supported by CONICYT Chile (FONDE-CYT Postdoctorado #317087

Cl Anion-Dependent Mg-ATPase

We studied, in the rat brain, the synaptosomal and microsomal membrane fractions of Cl− ion-activated, Mg2+-dependent ATPase, satisfying the necessary kinetic peculiarities of transport ATPases, by a novel method of kinetic analysis of the multisite enzyme systems: (1) the [Mg-ATP] complex constitutes the substrate of the enzymic reaction; (2) the V = f(Cl−) dependence-reflecting curve is bell-shaped; (3) substrate dependence, V = f(S), curves at a constant concentration of free ligands (Mgf, ATPf, Cl−); (4) as known from the literature, in the process of reaction a phosphorylated intermediate is formed (Gerencser, Crit Rev Biochem Mol Biol 31:303–337, 1996). We report on the Cl-ATPase molecular mechanism and its place in the “P-type ATPase” classification

Chemical mediation as a structuring element in marine gastropod predator-prey interactions

Chemical mediation regulates behavioral interactions between species and thus affects population structure, community organization and ecosystem function. Among marine taxa that have developed chemical mediation strategies, gastropods belong to a diverse group of molluscs found worldwide, including species with a coiled, reduced or absent shell. Most gastropods use natural products to mediate a wide range of behaviors such as defense, prey location or interactions with con- and hetero-geners. Their chemically defended diet, such as cyanobacteria, algae, sponges, bryozoans and tunicates, provides them with a considerable opportunity either as shelter from predators, or as a means to enhance their own chemical defense. In addition to improving their defenses, molluscs also use prey secondary metabolites in complex chemical communication including settlement induction, prey detection and feeding preferences. The assimilation of prey secondary metabolites further provides the opportunity for interactions with conspecifics via diet-derived chemical cues or signals. This review intends to provide an overview on the sequestration, detoxification, and biotransformation of diet-derived natural products, as well as the role of these compounds as chemical mediators in gastropod-prey interactions

Short-term scientific mission at CSIC-Universidad de León: Potent in vitro anthelmintic effects of the seaweed Saccharina latissima against Teladorsagia circumcinta

Trabajo presentado al: JOINT COMBAR - ACSRPC meeting: Anthelmintic Resistance in Ruminants: Who cares? Abstract Book, Short Term Scientific Missions, pp. 36. Gante (Bélgica). 27-29 agosto 2019.Seaweed contains an abundance of bioactive compounds, and some seaweed species have been used for livestock feeding and as natural deworming agents for centuries. However, there is a lack of scientific evidence. In this study, we investigated the in vitro anthelmintic (AH) activity of extracts of seaweed from cold (Nordic) waters. We prepared three different extracts with hexane, dichlormethan:methanol (DCM), or water:methanol (WM) of dried and milled seaweed from four species: Saccharina latissima, Laminaria digitata, Ascophyllum nodosum, and Palmaria palmata. Both fermented (addition of Lactobacillus spp.) and non-fermented material (N=24) was included. The AH activity was assessed using an 48 hour Teladorsagia circumcincta first stage larval (L1) mortality assay (1 mg DM/mL dissolved in DMSO). The results showed a high AH activity of all six S. latissima extracts and fermented L. digitata extracts, and no activity of A. nodosum extracts. An egg hatch assay (EHA), using the same extracts (1 mg/mL, 48 h) and T. circumcincta eggs, showed >95% inhibition by the WM extracts of fermented and non-fermented S. latissima, and fermented L. digitata and P. palmata. We conclude that the seaweed S. latissima has a strong in vitro AH effect against eggs and L1 of the common sheep nematode T. circumcincta, and that fermentation of the other seaweeds may increase their ability to inhibit egg hatching

The Nordic Seaweeds Saccharina latissima and Laminaria digitata have potent anthelmintic effects in vitro

Trabajo presentado al: 27th International Conference of the World Association for the Advancement of Veterinary Parasitology. Abstract book, Oral Session OA28.01, pp. 108. Madison (USA). 7-11 julio 2019.Seaweed contains an abundance of bioactive compounds, and some seaweed species have been used as natural deworming agents for centuries in traditional Chinese medicine. In this study, we investigated the in vitro anthelmintic (AH) activity of extracts of seaweed, from Nordic waters. We prepared three di@erent extracts: hexane, dichlormethan:methanol (DCM), and water:methanol (WM), from four seaweed species: Saccharina latissima, Laminaria digitata, Ascophyllum nodosum, and Palmaria palmata. The AH activity was assessed using an Ascaris suum third stage larvae (L3) mortality assay (1 mg DM/mL dissolved in DMSO). Moving or coiled-up larvae were counted as alive, and immobile or straight larvae as dead. Extracts with more apolar compounds (hexane, DCM) showed higher AH activity than extracts with polar compounds (WM), and the most potent extracts originated from S. latissima and L. digitata, with an average mortality of >95% after 48 hours. Extracts from A. nodosum had significantly lower AH e@ect after 48 hours. The extracts were further tested for AH e@ect in vitro against Teladorsagia circumcincta L1 (1 mg/mL, 48 h). The results showed a high AH activity of S. latissima and very low activity of A. nodosum extracts. An egg hatch assa

MALT1 is a targetable driver of epithelial-to-mesenchymal transition in claudin-low, triple-negative breast cancer.

MALT1 is the effector protein of the CARMA/Bcl10/MALT1 (CBM) signalosome, a multiprotein complex that drives pro-inflammatory signaling pathways downstream of a diverse set of receptors. Although CBM activity is best known for its role in immune cells, emerging evidence suggests that it plays a key role in the pathogenesis of solid tumors, where it can be activated by selected G protein-coupled receptors (GPCR). Here, we demonstrated that overexpression of GPCRs implicated in breast cancer pathogenesis, specifically the receptors for Angiotensin II and thrombin (AT1R and PAR1), drove a strong epithelial-to-mesenchymal transition (EMT) program in breast cancer cells that is characteristic of claudin-low, triple-negative breast cancer (TNBC). In concert, MALT1 was activated in these cells and contributed to the dramatic EMT phenotypic changes through regulation of master EMT transcription factors including Snail and ZEB1. Importantly, blocking MALT1 signaling, through either siRNA-mediated depletion of MALT1 protein or pharmacologic inhibition of its activity, was effective at partially reversing the molecular and phenotypic indicators of EMT. Treatment of mice with mepazine, a pharmacologic MALT1 inhibitor, reduced growth of PAR1+, MDA-MB-231 xenografts and had an even more dramatic effect in reducing the burden of metastatic disease. These findings highlight MALT1 as an attractive therapeutic target for claudin-low TNBCs harboring overexpression of one or more selected GPCRs. IMPLICATIONS: This study nominates a GPCR/MALT1 signaling axis as a pathway that can be pharmaceutically targeted to abrogate EMT and metastatic progression in TNBC, an aggressive form of breast cancer that currently lacks targeted therapies