TACE inhibition: a promising therapeutic intervention against AATF-mediated steatohepatitis to hepatocarcinogenesis

Metabolic dysfunction-associated steatohepatitis-driven hepatocellular carcinoma (MASH-HCC) is a global clinical challenge for which there is a limited understanding of disease pathogenesis and a subsequent lack of therapeutic interventions. We previously identified that tumor necrosis factor-alpha (TNF-α) upregulated apoptosis antagonizing transcription factor (AATF) in MASH. Here, we investigated the effect of TNF-α converting enzyme (TACE) inhibition as a promising targeted therapy against AATF-mediated steatohepatitis to hepatocarcinogenesis. A preclinical murine model that recapitulates human MASH-HCC was used in the study. C57Bl/6 mice were fed with chow diet normal water (CD) or western diet sugar water (WD) along with a low dose of carbon tetrachloride (CCl4; 0.2 μL·g-1, weekly) for 24 weeks. TACE activity, TNF-α levels, and AATF expression were measured. The mice were treated with the TACE inhibitor Marimastat for 12 weeks, followed by analyses of liver injury, fibrosis, inflammation, and oncogenic signaling. In vitro experiments using stable clones of AATF control and AATF knockdown were also conducted. We found that AATF expression was upregulated in WD/CCl4 mice, which developed severe MASH at 12 weeks and advanced fibrosis with HCC at 24 weeks. WD/CCl4 mice showed increased TACE activity with reduced hepatic expression of sirtuin 1 (Sirt1) and tissue inhibitor of metalloproteinase 3 (Timp3). The involvement of the SIRT1/TIMP3/TACE axis was confirmed by the release of TNF-α, which upregulated AATF, a key molecular driver of MASH-HCC. Interestingly, TACE inhibition by Marimastat reduced liver injury, dyslipidemia, AATF expression, and oncogenic signaling, effectively preventing hepatocarcinogenesis. Furthermore, Marimastat inhibited the activation of JNK, ERK1/2, and AKT, which are key regulators of tumorigenesis in WD/CCl4 mice and in AATF control cells, but had no effect on AATF knockdown cells. This study shows that TACE inhibition prevents AATF-mediated inflammation, fibrosis, and oncogenesis in MASH-HCC, offering a potential target for therapeutic intervention.

Matrix Metalloproteinases Contribute to the Calcification Phenotype in Pseudoxanthoma Elasticum

Ectopic calcification and dysregulated extracellular matrix remodeling are prominent hallmarks of the complex heterogenous pathobiochemistry of pseudoxanthoma elasticum (PXE). The disease arises from mutations in ABCC6, an ATP-binding cassette transporter expressed predominantly in the liver. Neither its substrate nor the mechanisms by which it contributes to PXE are completely understood. The fibroblasts isolated from PXE patients and Abcc6-/- mice were subjected to RNA sequencing. A group of matrix metalloproteinases (MMPs) clustering on human chromosome 11q21-23, respectively, murine chromosome 9, was found to be overexpressed. A real-time quantitative polymerase chain reaction, enzyme-linked immunosorbent assay and immunofluorescent staining confirmed these findings. The induction of calcification by CaCl2 resulted in the elevated expression of selected MMPs. On this basis, the influence of the MMP inhibitor Marimastat (BB-2516) on calcification was assessed. PXE fibroblasts (PXEFs) exhibited a pro-calcification phenotype basally. PXEF and normal human dermal fibroblasts responded with calcium deposit accumulation and the induced expression of osteopontin to the addition of Marimastat to the calcifying medium. The raised MMP expression in PXEFs and during cultivation with calcium indicates a correlation of ECM remodeling and ectopic calcification in PXE pathobiochemistry. We assume that MMPs make elastic fibers accessible to controlled, potentially osteopontin-dependent calcium deposition under calcifying conditions.

Keel venom: Rhabdophis subminiatus (red-necked keelback) venom pathophysiologically affects diverse blood clotting pathways

Venoms are evolutionary novelties that have real-world implications due to their impact upon human health. However, relative to the abundant studies of elapid and viperid snake venoms, fewer investigations have been undertaken on those of rear-fanged snakes as they are more problematic for obtaining venom. While most rear-fanged venomous snakes are not considered to be of great medical importance, several species are capable of producing fatalities. Most notable among these are snakes from the genus Rhabdophis, the Asian "keelback" snakes. Prior work have described potent procoagulant toxicity suggesting Factor X and prothrombin activation, but did not investigate the ability to activate other clotting factors. Here we show that in addition to activating both Factor X and prothrombin (with prothrombin twice that of FX), the venom of Rhabdophis subminiatus is able to more potently activate Factor VII (ten times that of prothrombin), while also activating FXII and FIX equipotently to prothrombin, and with FXI also activated but at a much lower level. The ability to activate FVII represents a third convergent evolution of this trait. The Australian elapid clade of [Oxyuranus (taipans) + Pseudonaja (brown snakes)] was the first identified to have evolved this trait. and only recently was it shown to be independently present in another lineage (the Central American viperid species Porthidium volcanicum). In addition, the abilities to activate FXI and FXII are also convergent between R. subminiatus and P. volcanicum, but with R. subminiatus being much more potent. By testing across amphibian, avian, and mammalian plasmas we demonstrate that the venom is potently procoagulant across diverse plasma types. However, consistent with dietary preference, R. subminiatus venom was most potent upon amphibian plasma. While a Rhabdophis antivenom is produced in Japan to treat R. tigrinus envenomings, it is scarce even within Japan and is not exported. As this genus is very wide-ranging in Asia, alternate treatment options are in need of development. Hence we tested the ability of candidate, broad-spectrum enzyme inhibitors to neutralize R. subminiatus venom: marimastat was more effective than prinomastat but both marimastat and prinomastat were significantly more effective than DMPS (2,3-Dimercapto-1-propanesulfonic acid). The findings of this study shed light on the evolution of these fascinating rear-fanged snakes as well as explored their systemic effects upon blood coagulation and point to potential treatment options for the rare, but potentially lethal encounters.

Neutralising effects of small molecule toxin inhibitors on nanofractionated coagulopathic Crotalinae snake venoms

Repurposing small molecule drugs and drug candidates is considered as a promising approach to revolutionise the treatment of snakebite envenoming. In this study, we investigated the inhibiting effects of the small molecules varespladib (nonspecific phospholipase A2 inhibitor), marimastat (broad spectrum matrix metalloprotease inhibitor) and dimercaprol (metal ion chelator) against coagulopathic toxins found in Crotalinae (pit vipers) snake venoms. Venoms from Bothrops asper, Bothrops jararaca, Calloselasma rhodostoma and Deinagkistrodon acutus were separated by liquid chromatography, followed by nanofractionation and mass spectrometry identification undertaken in parallel. Nanofractions of the venom toxins were then subjected to a high-throughput coagulation assay in the presence of different concentrations of the small molecules under study. Anticoagulant venom toxins were mostly identified as phospholipases A2, while procoagulant venom activities were mainly associated with snake venom metalloproteinases and snake venom serine proteases. Varespladib was found to effectively inhibit most anticoagulant venom effects, and also showed some inhibition against procoagulant toxins. Contrastingly, marimastat and dimercaprol were both effective inhibitors of procoagulant venom activities but showed little inhibitory capability against anticoagulant toxins. The information obtained from this study aids our understanding of the mechanisms of action of toxin inhibitor drug candidates, and highlights their potential as future snakebite treatments.

A drug-delivering-drug strategy for combined treatment of metastatic breast cancer

Treatment of metastatic cancer continues to be a huge challenge worldwide. Notably, drug nanocrystals (Ns) in nanosuspensions clearly belong to a type of nanoparticle. Therefore, a question arose as to whether these drug particles can also be applied as carriers for drug delivery. Here, we design a novel paclitaxel (PTX) nanocrystal stabilized with complexes of matrix metalloproteinase (MMP)-sensitive β-casein/marimastat (MATT) for co-delivering MATT and PTX and combined therapy of metastatic breast cancer. The prepared Ns (200 nm) with a drug-loading of >50% were potent in treatment of metastatic cancer, which markedly inhibited MMP expression and activity and greatly blocked the lung metastasis and angiogenesis. In conclusion, employing protein-drug complexes as stabilizers, Ns with dual payloads are developed and are a promising strategy for co-delivery. Furthermore, the developed Ns can target the tumor microenvironment and cancer cells and, as a result, enable efficient treatment for breast metastatic cancer.

Degradation of extracellular matrix regulates osteoblast migration: A microfluidic-based study

Bone regeneration is strongly dependent on the capacity of cells to move in a 3D microenvironment, where a large cascade of signals is activated. To improve the understanding of this complex process and to advance in the knowledge of the role of each specific signal, it is fundamental to analyze the impact of each factor independently. Microfluidic-based cell culture is an appropriate technology to achieve this objective, because it allows recreating realistic 3D local microenvironments by taking into account the extracellular matrix, cells and chemical gradients in an independent or combined scenario. The main aim of this work is to analyze the impact of extracellular matrix properties and growth factor gradients on 3D osteoblast movement, as well as the role of cell matrix degradation. For that, we used collagen-based hydrogels, with and without crosslinkers, under different chemical gradients, and eventually inhibiting metalloproteinases to tweak matrix degradation. We found that osteoblast's 3D migratory patterns were affected by the hydrogel properties and the PDGF-BB gradient, although the strongest regulatory factor was determined by the ability of cells to remodel the matrix.

Peptidomimetic hydroxamate metalloproteinase inhibitors abrogate local and systemic toxicity induced by Echis ocellatus (saw-scaled) snake venom

The ability of two peptidomimetic hydroxamate metalloproteinase inhibitors, Batimastat and Marimastat, to abrogate toxic and proteinase activities of the venom of Echis ocellatus from Cameroon and Ghana was assessed. Since this venom largely relies for its toxicity on the action of zinc-dependent metalloproteinases (SVMPs), the hypothesis was raised that toxicity could be largely eliminated by using SVMP inhibitors. Both hydroxamate molecules inhibited local and pulmonary hemorrhagic, in vitro coagulant, defibrinogenating, and proteinase activities of the venoms in conditions in which venom and inhibitors were incubated prior to the test. In addition, the inhibitors prolonged the time of death of mice receiving 4 LD₅₀s of venom by the intravenous route. Lower values of IC₅₀ were observed for in vitro and local hemorrhagic activities than for systemic effects. When experiments were performed in conditions that simulated the actual circumstances of snakebite, i.e. by administering the inhibitor after envenoming, Batimastat completely abrogated local hemorrhage if injected immediately after venom. Moreover, it was also effective at inhibiting lethality and defibrinogenation when venom and inhibitor were injected by the intraperitoneal route. Results suggest that these, and possibly other, metalloproteinase inhibitors may become an effective adjunct therapy in envenomings by E. ocellatus when administered at the anatomic site of venom injection rapidly after the bite.