-
Toxins Jul 2022Within Neotropical pit-vipers, the Mexican/Central-American clade consisting of , , , and is a wide-ranging, morphologically and ecologically diverse group of snakes....
Within Neotropical pit-vipers, the Mexican/Central-American clade consisting of , , , and is a wide-ranging, morphologically and ecologically diverse group of snakes. Despite their prevalence, little is known of the functional aspects of their venoms. This study aimed to fill the knowledge gap regarding coagulotoxic effects and to examine the potential of different therapeutic approaches. As a general trait, the venoms were shown to be anticoagulant but were underpinned by diverse biochemical actions. Pseudo-procoagulant activity (i.e., thrombin-like), characterized by the direct cleavage of fibrinogen to form weak fibrin clots, was evident for , , and In contrast, other venoms cleaved fibrinogen in a destructive (non-clotting) manner, with and being the most potent. In addition to actions on fibrinogen, clotting enzymes were also inhibited. FXa was only weakly inhibited by most species, but and were extremely strong in their inhibitory action. Other clotting enzymes were more widely inhibited by diverse species spanning the full taxonomical range, but in each case, there were species that had these traits notably amplified relatively to the others. and were the most potent amongst those that inhibited the formation of the prothrombinase complex and were also amongst the most potent inhibitors of Factor XIa. While most species displayed only low levels of thrombin inhibition, potently inhibited this clotting factor. The regional polyvalent antivenom produced by Instituto Picado Clodomiro was tested and was shown to be effective against the diverse anticoagulant pathophysiological effects. In contrast to the anticoagulant activities of the other species, was uniquely procoagulant through the activation of Factor VII and Factor XII. This viperid species is the first snake outside of the elapid snake clade to be shown to activate FVII and the first snake venom of any kind to activate FXII. Interestingly, while small-molecule metalloprotease inhibitors prinomastat and marimastat demonstrated the ability to prevent the procoagulant toxicity of , neither ICP antivenom nor inhibitor DMPS showed this effect. The extreme variation among the snakes here studied underscores how venom is a dynamic trait and how this can shape clinical outcomes and influence evolving treatment strategies.
Topics: Animals; Anticoagulants; Antivenins; Crotalid Venoms; Crotalinae; Elapid Venoms; Elapidae; Fibrinogen; Snake Venoms; Thrombin; Viperidae
PubMed: 35893753
DOI: 10.3390/toxins14080511 -
Nature Communications Dec 2023Morbidity from snakebite envenoming affects approximately 400,000 people annually. Tissue damage at the bite-site often leaves victims with catastrophic life-long...
Morbidity from snakebite envenoming affects approximately 400,000 people annually. Tissue damage at the bite-site often leaves victims with catastrophic life-long injuries and is largely untreatable by current antivenoms. Repurposed small molecule drugs that inhibit specific snake venom toxins show considerable promise for tackling this neglected tropical disease. Using human skin cell assays as an initial model for snakebite-induced dermonecrosis, we show that the drugs 2,3-dimercapto-1-propanesulfonic acid (DMPS), marimastat, and varespladib, alone or in combination, inhibit the cytotoxicity of a broad range of medically important snake venoms. Thereafter, using preclinical mouse models of dermonecrosis, we demonstrate that the dual therapeutic combinations of DMPS or marimastat with varespladib significantly inhibit the dermonecrotic activity of geographically distinct and medically important snake venoms, even when the drug combinations are delivered one hour after envenoming. These findings strongly support the future translation of repurposed drug combinations as broad-spectrum therapeutics for preventing morbidity caused by snakebite.
Topics: Mice; Humans; Animals; Snake Bites; Snake Venoms; Drug Combinations
PubMed: 38097534
DOI: 10.1038/s41467-023-43510-w -
Biomolecules Apr 2023Ectopic calcification and dysregulated extracellular matrix remodeling are prominent hallmarks of the complex heterogenous pathobiochemistry of 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 , 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 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 CaCl 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.
Topics: Humans; Mice; Animals; Pseudoxanthoma Elasticum; Osteopontin; Calcium; Calcinosis; Phenotype; Matrix Metalloproteinases; Multidrug Resistance-Associated Proteins
PubMed: 37189419
DOI: 10.3390/biom13040672 -
Gut Oct 2014Polycystic liver diseases (PCLDs) are genetic disorders characterised by progressive bile duct dilatation and/or cyst development. Their pathogenesis is a consequence of...
OBJECTIVE
Polycystic liver diseases (PCLDs) are genetic disorders characterised by progressive bile duct dilatation and/or cyst development. Their pathogenesis is a consequence of hyperproliferation, hypersecretion and microRNA alterations in cholangiocytes. Here we evaluate the role of matrix metalloproteases (MMPs) in the hepatic cystogenesis of PCLDs.
DESIGN
Metalloprotease activity was measured by microfluorimetric assays in normal and polycystic cholangiocyte cultures from humans and rats, and gene expression by real time quantitative PCR. The role of cytokines, oestrogens and growth factors present in the cystic fluid of PCLD patients was evaluated for MMP activity. The MMP inhibitor marimastat was examined for cystic expansion in vitro and in polycystic kidney (PCK) rats.
RESULTS
Polycystic human and rat cholangiocytes displayed increased MMP activity, which was associated with increased mRNA levels of different MMPs. Interleukin (IL)-6 and IL-8, and 17β-oestradiol, all stimulated MMP activity in human cholangiocytes. The presence of antibodies against IL-6 and/or IL-8 receptor/s inhibited baseline MMP hyperactivity of polycystic human cholangiocytes but had no effect on normal human cholangiocytes. MMP-3 was overexpressed in cystic cholangiocytes from PCLD human and PCK rat livers by immunohistochemistry. Marimastat reduced MMP hyperactivity of polycystic human and rat cholangiocytes and blocked the cystic expansion of PCK cholangiocytes cultured in three-dimensions. Chronic treatment of 8-week-old PCK rats with marimastat inhibited hepatic cystogenesis and fibrosis.
CONCLUSIONS
PCLDs are associated with cholangiocyte MMP hyperactivity resulting from autocrine/paracrine stimulation by IL-6 and IL-8. Inhibition of this MMP hyperactivity with marimastat decreased hepatic cystogenesis in vitro and in an animal model of PCLD, offering a potential therapeutic tool.
Topics: Animals; Bile Ducts; Blotting, Western; Cell Culture Techniques; Cysts; Cytokines; Cytophotometry; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Hydroxamic Acids; Immunohistochemistry; Liver; Liver Diseases; Male; Metalloendopeptidases; Rats; Real-Time Polymerase Chain Reaction
PubMed: 24436140
DOI: 10.1136/gutjnl-2013-305281 -
The Journal of Parasitology Aug 2018In the course of a structure based drug discovery program the known anticancer candidate marimastat was uncovered as a potent inhibitor of an enzyme in nematode cuticle...
In the course of a structure based drug discovery program the known anticancer candidate marimastat was uncovered as a potent inhibitor of an enzyme in nematode cuticle biogenesis. It was shown to kill Caenorhabditis elegans, and the sheep parasites Haemonchus contortus and Teladorsagia circumcinta via an entirely novel nematode-specific pathway, specifically by inhibiting cuticle-remodelling enzymes that the parasites require for the developmentally essential moulting process. This discovery prompted an investigation of the compound's effect on Heligmosomoides polygyrus parasites in a mouse model of helminth infection. Mice were administered the drug via oral gavage daily from day of infection for a period of 2 wk. A second group received the drug via intra-peritoneal implantation of an osmotic minipump for 4 wk. Control groups were administered identical volumes of water by oral gavage in both cases. Counts of H. polygyrus faecal egg and larval load showed that marimastat effected a consistent and significant reduction in egg laying, and a consistent but minor reduction in adult worm load when administered every day, starting on the first day of infection. However, the drug failed to have any significant effect on egg counts or worm burdens when administered to mice with established infections. Therefore, marimastat does not appear to show promise as an anthelmintic in gastrointestinal nematode infections, although other metalloproteases such as batimastat may prove more effective.
PubMed: 30085900
DOI: 10.1645/18-33 -
Molecules (Basel, Switzerland) Mar 2022Snakebite remains a significant public health burden globally, disproportionately affecting low-income and impoverished regions of the world. Recently, researchers have...
Snakebite remains a significant public health burden globally, disproportionately affecting low-income and impoverished regions of the world. Recently, researchers have begun to focus on the use of small-molecule inhibitors as potential candidates for the neutralisation of key snake venom toxins and as potential field therapies. vipers represent some of the most medically important as well as frequently encountered snake species in Africa, with a number of species possessing anticoagulant phospholipase A (PLA) toxins that prevent the prothrombinase complex from inducing clot formation. Additionally, species within the genus are known to exert pseudo-procoagulant activity, whereby kallikrein enzymatic toxins cleave fibrinogen to form a weak fibrin clot that rapidly degrades, thereby depleting fibrinogen levels and contributing to the net anticoagulant state. Utilising well-validated coagulation assays measuring time until clot formation, this study addresses the in vitro efficacy of three small molecule enzyme inhibitors (marimastat, prinomastat and varespladib) in neutralising these aforementioned activities. The PLA inhibitor varespladib showed the greatest efficacy for the neutralisation of PLA-driven anticoagulant venom activity, with the metalloproteinase inhibitors prinomastat and marimastat both showing low and highly variable degrees of cross-neutralisation with PLA anticoagulant toxicity. However, none of the inhibitors showed efficacy in neutralising the pseudo-procoagulant venom activity exerted by the venom of . Our results highlight the complex nature of snake venoms, for which single-compound treatments will not be universally effective, but combinations might prove highly effective. Despite the limitations of these inhibitors with regards to in vitro kallikrein enzyme pseudo-procoagulant venom activity, our results further support the growing body of literature indicating the potential use of small molecule inhibitors to enhance first-aid treatment of snakebite envenoming, particularly in cases where hospital and thus antivenom treatment is either unavailable or far away.
Topics: Animals; Viperidae
PubMed: 35268832
DOI: 10.3390/molecules27051733 -
Journal of Proteomics Jan 2017ADAM17 (a disintegrin and metalloproteinase 17) is a plasma membrane metalloprotease involved in proteolytic release of the extracellular domain of many cell surface...
UNLABELLED
ADAM17 (a disintegrin and metalloproteinase 17) is a plasma membrane metalloprotease involved in proteolytic release of the extracellular domain of many cell surface molecules, a process known as ectodomain shedding. Through this process, ADAM17 is implicated in several aspects of tumor growth and metastasis in a broad range of tumors, including head and neck squamous cell carcinomas (HNSCC). In this study, mass spectrometry-based proteomics approaches revealed glypican-1 (GPC1) as a new substrate for ADAM17, and its shedding was confirmed to be metalloprotease-dependent, induced by a pleiotropic agent (PMA) and physiologic ligand (EGF), and inhibited by marimastat. In addition, immunoblotting analysis of GPC1 in the extracellular media from control and ADAM17shRNA pointed to a direct involvement of ADAM17 in the cleavage of GPC1. Moreover, mass spectrometry-based interactome analysis of GPC1 revealed biological functions and pathways related mainly to cellular movement, adhesion and proliferation, which were events also modulated by up regulation of full length and cleavage GPC1. Altogether, we showed that GPC1 is a novel ADAM17 substrate, thus the function of GPC1 may be modulated by proteolysis signaling.
BIOLOGICAL SIGNIFICANCE
Inhibition of metalloproteases as a therapeutic approach has failed because there is limited knowledge of the degradome of individual proteases as well as the cellular function of cleaved substrates. Using different proteomic techniques, this study uncovered novel substrates that can be modulated by ADAM17 in oral squamous cell carcinoma cell line. Glypican-1 was validated as a novel substrate for ADAM17, with important function in adhesion, proliferation and migration of carcinoma cells. Therefore, this study opens new avenues regarding the proteolysis-mediated function of GPC1 by ADAM17.
Topics: ADAM17 Protein; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell-Derived Microparticles; Glypicans; Head and Neck Neoplasms; Humans; Mass Spectrometry; Metalloproteases; Protein Binding; Proteolysis; Proteomics; Squamous Cell Carcinoma of Head and Neck
PubMed: 27576135
DOI: 10.1016/j.jprot.2016.08.017 -
Veterinary Journal (London, England :... Sep 2015No validated laminitis drug therapy exists, yet pharmaceutical agents with potential for laminitis prevention have been identified. Many of these are impractical for... (Clinical Trial)
Clinical Trial Comparative Study
No validated laminitis drug therapy exists, yet pharmaceutical agents with potential for laminitis prevention have been identified. Many of these are impractical for systemic administration but may be effective if administered locally. This study compared intraosseous infusion of the distal phalanx (IOIDP) with systemic intravenous constant rate infusion (CRI) to determine which was more effective for lamellar marimastat delivery. Ultrafiltration probes were placed in both forefeet of five horses to collect lamellar interstitial fluid as lamellar ultrafiltrate (LUF). Marimastat solution (3.5 mg/mL) containing lidocaine (20 mg/mL) was infused by IOIDP at 0.15 mL/min for 12 h. After a 12 h wash-out, marimastat (3.5 mg/mL) and lidocaine were infused by constant rate infusion (CRI) at 0.15 mL/min for 12 h. LUF, plasma and lamellar tissue marimastat concentrations were quantified using UPLC-MS. Zymography was used to establish the inhibitory concentrations of marimastat for equine lamellar matrix metalloproteinases (MMPs). Data were analysed non-parametrically. There was no difference between the steady-state marimastat concentration in lamellar ultrafiltrate (LUF[M]) during IOIDP (139[88-497] ng/mL) and CRI (136[93-157] ng/mL). During IOIDP, there was no difference between marimastat concentrations in the treated foot (139[88-497] ng/mL), the untreated foot (91[63-154] ng/mL) and plasma (101[93-118] ng/mL). LUF[M] after IOIDP and CRI were >IC50 of lamellar MMP-2 and 9, but below the concentration considered necessary for in vivo laminitis prevention. Lamellar drug delivery during IOIDP was inconsistent and did not achieve higher lamellar marimastat concentrations than CRI. Modification or refinement of the IOIDP technique is necessary if it is to be consistently effective.
Topics: Animals; Female; Foot Diseases; Hoof and Claw; Horse Diseases; Horses; Hydroxamic Acids; Infusions, Intraosseous; Infusions, Intravenous; Male; Matrix Metalloproteinase Inhibitors
PubMed: 26073286
DOI: 10.1016/j.tvjl.2015.05.010 -
Journal of Thrombosis and Haemostasis :... Jul 2023ADAMTS13 is a circulating metalloprotease that cleaves von Willebrand factor (VWF) in a shear-dependent manner. ADAMTS13 is secreted as an active protease but has a long...
BACKGROUND
ADAMTS13 is a circulating metalloprotease that cleaves von Willebrand factor (VWF) in a shear-dependent manner. ADAMTS13 is secreted as an active protease but has a long half-life, suggesting that it is resistant to circulating protease inhibitors. These zymogen-like properties indicate that ADAMTS13 exists as a latent protease that is activated by its substrate.
OBJECTIVES
To investigate the mechanism of ADAMTS13 latency and resistance to metalloprotease inhibitors.
METHODS
Probe the active site of ADAMTS13 and variants using alpha-2 macroglobulin (A2M), tissue inhibitors of metalloproteases (TIMPs), and Marimastat.
RESULTS
ADAMTS13 and C-terminal deletion mutants are not inhibited by A2M, TIMPs, or Marimastat, but cleave FRETS-VWF73, suggesting that the metalloprotease domain is latent in the absence of substrate. Within the metalloprotease domain, mutating the gatekeeper triad (R193, D217, D252) or substituting the calcium-binding (R180-R193) or the variable (G236-S263) loops with corresponding features from ADAMTS5 did not sensitize MDTCS to inhibition. However, substituting the calcium-binding loop and an extended variable loop (G236-S263) corresponding to the S1-S1' pockets with those from ADAMTS5, resulted in MDTCS-GVC5 inhibition by Marimastat, but not by A2M or TIMP3. Substituting the MD domains of ADAMTS5 into full-length ADAMTS13 resulted in a 50-fold reduction in activity compared with the substitution into MDTCS. However, both chimeras were susceptible to inhibition, suggesting that the closed conformation does not contribute to the latency of the metalloprotease domain.
CONCLUSION
The metalloprotease domain protects ADAMTS13 from inhibitors and exists in a latent state that is partially maintained by loops flanking the S1 and S1' specificity pockets.
Topics: Humans; von Willebrand Factor; ADAM Proteins; Calcium; Hydroxamic Acids; ADAMTS13 Protein
PubMed: 36990157
DOI: 10.1016/j.jtha.2023.03.021 -
Cancer Medicine Jun 2024We previously reported that metastases are generally characterized by a core program of gene expression that activates tissue remodeling/vascularization, alters ion...
BACKGROUND
We previously reported that metastases are generally characterized by a core program of gene expression that activates tissue remodeling/vascularization, alters ion homeostasis, induces the oxidative metabolism, and silences extracellular matrix interactions. This core program distinguishes metastases from their originating primary tumors as well as from their destination host tissues. Therefore, the gene products involved are potential targets for anti-metastasis drug treatment.
METHODS
Because the silencing of extracellular matrix interactions predisposes to anoiks in the absence of active survival mechanisms, we tested inhibitors against the other three components.
RESULTS
Individually, the low-specificity VEGFR blocker pazopanib (in vivo combined with marimastat), the antioxidant dimethyl sulfoxide (or the substitute atovaquone, which is approved for internal administration), and the ionic modulators bumetanide and tetrathiomolybdate inhibited soft agar colony formation by breast and pancreatic cancer cell lines. The individual candidate agents have a record of use in humans (with limited efficacy when administered individually) and are available for repurposing. In combination, the effects of these drugs were additive or synergistic. In two mouse models of cancer (utilizing 4T1 cells or B16-F10 cells), the combination treatment with these medications, applied immediately (to prevent metastasis formation) or after a delay (to suppress established metastases), dramatically reduced the occurrence of disseminated foci.
CONCLUSIONS
The combination of tissue remodeling inhibitors, suppressors of the oxidative metabolism, and ion homeostasis modulators has very strong promise for the treatment of metastases by multiple cancers.
Topics: Animals; Humans; Mice; Sulfonamides; Cell Line, Tumor; Pyrimidines; Female; Indazoles; Neoplasm Metastasis; Molybdenum; Antineoplastic Combined Chemotherapy Protocols; Breast Neoplasms; Pancreatic Neoplasms; Xenograft Model Antitumor Assays
PubMed: 38826119
DOI: 10.1002/cam4.7291