Metalloproteinases in disease: identification of biomarkers of tissue damage through proteomics

Dermatopathological findings of Bothrops atrox snakebites: A case series in the Brazilian Amazon

BACKGROUND

Bothrops venom consists primarily of metalloproteinase and phospholipase A2 toxins, which are responsible for the acute inflammatory, coagulant and hemorrhagic action following snakebite. The local effects of snakebite envenomation by Bothrops species are particularly prevalent yet poorly studied, but include pain, edema, erythema, blistering, bleeding, and ecchymosis.

METHODS AND FINDINGS

In this study, we describe the dermatopathological findings observed in a series of 22 patients diagnosed with Bothrops envenomation treated in a tertiary hospital of Manaus, in the Brazilian Amazon. Clinically, pain and edema were observed in all patients, followed by fang marks (63.6%), secondary infection (36.3%), ecchymosis (31.8%), erythema (22.7%), blister (13.6%), and necrosis (4.5%). Regarding histopathological findings, epidermal alterations such as spongiosis, acanthosis and hyperkeratosis were the most observed characteristics in our cases series, with isolated cases of hyperplasia, hemorrhagic intraepidermal blister and severe necrosis. Changes in dermis and hypodermis consisted mainly of hemorrhage, inflammatory infiltrate, edema, congestion, and vascular damage, whereas cases of collagen damage, necrosis, abscess, and signs of tissue repair, indicated by the presence of granulation tissue, were also observed, with a persistence of inflammatory and hemostatic alterations even days after antivenom administration. Therefore, the tissue damage resulting from Bothrops envenomation could be related to both direct venom activity as well as inflammatory response or presence of infectious process. The histopathological analysis of human skin injury can enlighten the pathological and endogenous effects of local envenomation and could underpin new strategies, including novel treatments, adjuvants or changes in clinical management, that lead to better outcomes in snakebite patients.

Proteomic study of localized tissue necrosis by Naja atra venom

Naja atra bites often result in immediate and severe illness. The venom of N. atra contains a complex mixture of toxins that can cause significant damage to the patient's skin tissue. If left untreated, this condition can progress to localized necrosis, potentially resulting in impairment or even amputation in severe cases. Despite the known effects of the venom, the exact mechanisms underlying this tissue necrosis are not fully understood. This study aimed to investigate the protein components responsible for tissue necrosis induced by N. atra venom at both the organism-wide and molecular levels. To achieve this, venom was injected into Bama miniature pigs to cause ulcers, and exudate samples were collected at various time points after injection. Label-free proteomics analysis identified 1119, 1016, 938, 864, and 855 proteins in the exudate at 6, 12, 24, 36, and 48 h post-injection, respectively. Further analysis revealed 431 differentially expressed proteins, with S100A8, MMP-2, MIF, and IDH2 identified as proteins associated with local tissue necrosis. In this study, we established a Bama miniature pig model for N. atra venom injection and performed proteomic analysis of the wound exudate, which provides important insights into the molecular pathology of snakebite-induced tissue necrosis and potential theoretical bases for clinical treatment. Proteomic data from this study can be accessed through ProteomeXchange using the identifier PXD052498.

BjussuMP-II, a venom metalloproteinase, induces the release and cleavage of pro-inflammatory cytokines and disrupts human umbilical vein endothelial cells

Snake venom metalloproteases (SVMPs) are hydrolytic enzymes dependent on metal binding, primarily zinc (Zn2+), at their catalytic site. They are classified into three classes (P-I to P-III). BjussuMP-II, a P-I SVMP isolated from Bothrops jararacussu snake venom, has a molecular mass of 24 kDa. It exhibits inhibitory activity on platelet aggregation and hydrolyzes fibrinogen. TNF-α upregulates the expression of adhesion molecules on endothelial cell surfaces, promoting leukocyte adhesion and migration during inflammation. Literature indicates that SVMPs may cleave the TNF-α precursor, possibly due to significant homology between metalloproteases from mammalian extracellular matrix and SVMPs. This study aimed to investigate BjussuMP-II's effects on human umbilical vein endothelial cells (HUVEC), focusing on viability, detachment, adhesion, release, and cleavage of TNF-α, IL-1β, IL-6, IL-8, and IL-10. HUVEC were incubated with BjussuMP-II (1.5-50 μg/mL) for 3-24 h. Viability was determined using LDH release, MTT metabolization, and 7AAD for membrane integrity. Adhesion and detachment were assessed by incubating cells with BjussuMP-II and staining with Giemsa. Cytokines were quantified in HUVEC supernatants using EIA. TNF-α cleavage was evaluated using supernatants from PMA-stimulated cells or recombinant TNF-α. Results demonstrated BjussuMP-II's proteolytic activity on casein. It was not toxic to HUVEC at any concentration or duration studied but interfered with adhesion and promoted detachment. PMA induced TNF-α release by HUVEC, but this effect was not observed with BjussuMP-II, which cleaved TNF-α. Additionally, BjussuMP-II cleaved IL-1β, IL-6, and IL-10. These findings suggest that the zinc metalloprotease BjussuMP-II could be a valuable biotechnological tool for treating inflammatory disorders involving cytokine deregulation.

Tissue damaging toxins in snake venoms: mechanisms of action, pathophysiology and treatment strategies

Snakebite envenoming is an important public health issue responsible for mortality and severe morbidity. Where mortality is mainly caused by venom toxins that induce cardiovascular disturbances, neurotoxicity, and acute kidney injury, morbidity is caused by toxins that directly or indirectly destroy cells and degrade the extracellular matrix. These are referred to as 'tissue-damaging toxins' and have previously been classified in various ways, most of which are based on the tissues being affected (e.g., cardiotoxins, myotoxins). This categorisation, however, is primarily phenomenological and not mechanistic. In this review, we propose an alternative way of classifying cytotoxins based on their mechanistic effects rather than using a description that is organ- or tissue-based. The mechanisms of toxin-induced tissue damage and their clinical implications are discussed. This review contributes to our understanding of fundamental biological processes associated with snakebite envenoming, which may pave the way for a knowledge-based search for novel therapeutic options.

Feasibility of detecting snake envenomation biomarkers from dried blood spots

Biofluid proteomics is a sensitive and high throughput technique that provides vast amounts of molecular data for biomarker discovery. More recently, dried blood spots (DBS) have gained traction as a stable, noninvasive, and relatively cheap source of proteomic data for biomarker identification in disease and injury. Snake envenomation is responsible for significant morbidity and mortality worldwide; however, much remains unknown about the systemic molecular response to envenomation and acquiring biological samples for analysis is a major hurdle. In this study, we utilized DBS acquired from a case of lethal rattlesnake envenomation to determine the feasibility of discovering biomarkers associated with human envenomation. We identified proteins that were either unique or upregulated in envenomated blood compared to non-envenomated blood and evaluated if physiological response pathways and protein markers that correspond to the observed syndromes triggered by envenomation could be detected. We demonstrate that DBS provide useful proteomic information on the systemic processes that resulted from envenomation in this case and find evidence for a massive and systemic inflammatory cascade, combined with coagulation dysregulation, complement system activation, hypoxia response activation, and apoptosis. We also detected potential markers indicative of lethal anaphylaxis, cardiac arrest, and brain death. Ultimately, DBS proteomics has the potential to provide stable and sensitive molecular data on envenomation syndromes and response pathways, which is particularly relevant in low-resource areas which may lack the materials for biofluid processing and storage.

Structural and evolutionary insights into astacin metallopeptidases

The astacins are a family of metallopeptidases (MPs) that has been extensively described from animals. They are multidomain extracellular proteins, which have a conserved core architecture encompassing a signal peptide for secretion, a prodomain or prosegment and a zinc-dependent catalytic domain (CD). This constellation is found in the archetypal name-giving digestive enzyme astacin from the European crayfish Astacus astacus. Astacin catalytic domains span ∼200 residues and consist of two subdomains that flank an extended active-site cleft. They share several structural elements including a long zinc-binding consensus sequence (HEXXHXXGXXH) immediately followed by an EXXRXDRD motif, which features a family-specific glutamate. In addition, a downstream SIMHY-motif encompasses a "Met-turn" methionine and a zinc-binding tyrosine. The overall architecture and some structural features of astacin catalytic domains match those of other more distantly related MPs, which together constitute the metzincin clan of metallopeptidases. We further analysed the structures of PRO-, MAM, TRAF, CUB and EGF-like domains, and described their essential molecular determinants. In addition, we investigated the distribution of astacins across kingdoms and their phylogenetic origin. Through extensive sequence searches we found astacin CDs in > 25,000 sequences down the tree of life from humans beyond Metazoa, including Choanoflagellata, Filasterea and Ichtyosporea. We also found < 400 sequences scattered across non-holozoan eukaryotes including some fungi and one virus, as well as in selected taxa of archaea and bacteria that are pathogens or colonizers of animal hosts, but not in plants. Overall, we propose that astacins originate in the root of Holozoa consistent with Darwinian descent and that the latter genes might be the result of horizontal gene transfer from holozoan donors.

ADAM12 is an independent predictor of poor prognosis in liver cancer

Disintegrin and metalloproteinase 12 (ADAM12) is thought to trigger the occurrence and development of numerous tumours, including colorectal, breast, and pancreatic cancers. On the basis of The Cancer Genome Atlas (TCGA) datasets, in this study, the relationship between ADAM12 gene expression and hepatocellular carcinoma (HCC), the prognostic value of this relationship, and the potential mechanisms influencing HCC development were evaluated. The results showed that the ADAM12 gene was significantly and highly expressed in liver cancer tissue. The high expression of the ADAM12 gene in liver cancer tissue significantly and positively correlated with T stage, pathological stage, and residual tumour. Kaplan–Meier and Cox regression analyses revealed that ADAM12 gene expression is an independent risk factor influencing the prognosis of patients with liver cancer. Pathway analyses of ADAM12 in HCC revealed ADAM12-correlated signalling pathways, and the expression level of ADAM12 was associated with immune cell infiltration. In vitro experiments demonstrated that the expression level of ADAM12 in Huh-7 and Hep3B cells was significantly higher than that in other HCC cells. ShRNA transfection experiments confirmed that the expression levels of TGF-β and Notch pathway-related proteins were significantly decreased. An EdU cell proliferation assay showed that a low level of ADAM12 gene expression significantly inhibited the proliferative activity of HCC cells. Cell cycle experiments showed that low ADAM12 expression blocked the G1/S phase transition. Overall, this research revealed that high ADAM12 gene expression implies a poor prognosis for patients with primary liver cancer. In addition, it is a potential indicator for the diagnosis of liver cancer.

Combination of ebselen and hydrocortisone substantially reduces nitrogen mustard-induced cutaneous injury

The purpose of the present study was to investigate the vesicant countermeasure effects of hydrocortisone (HC) and ebselen (EB-1), administered as monotherapy or as a combination treatment. The mouse ear vesicant model (MEVM) was utilized and test doses of HC (0.016, 0.023, 0.031, 0.047, 0.063, 0.125 or 0.250 mg/ear), EB-1 (0.125, 0.187, 0.250, 0.375 or 0.500 mg/ear) or the combination of HC + EB-1 were topically applied at 15 min, 4 h and 8 h after nitrogen mustard exposure. Ear punch biopsies were obtained 24 h after mechlorethamine (HN2) exposure. Compared to control ears, ear tissues exposed topically to HN2 (0.500 µmol/ear) presented with an increase in ear thickness, vesication, TUNEL fluorescence and expression of matrix metalloproteinase 9 (MMP-9) and inducible nitric oxide synthase (iNOS). In contrast, HN2 exposed ears treated topically with EB-1 showed a significant decrease in morphometric thickness and vesication vs. HN2 alone. Ear tissues exposed to HN2 and then treated with HC also demonstrated reductions in morphometric thickness and vesication. Combination treatment of HC + EB-1 was found to be the most effective at reducing HN2-induced ear edema and vesication. The combination also dramatically decreased HN2-mediated cutaneous expression of iNOS and MMP-9 and decreased HN2-induced TUNEL staining. Taken together, our study demonstrates that the combination of HC + EB-1 is an efficacious countermeasure to HN2.

A Disintegrin and Metalloprotease 12 Promotes Tumor Progression by Inhibiting Apoptosis in Human Colorectal Cancer

Simple Summary

A disintegrin and metalloprotease 12 (ADAM12) has been associated with tumor development and progression. The aim of the current study was to evaluate the impact of ADAM12 on cancer progression, prognosis, and therapeutic targets in colorectal cancer (CRC). Our results show that ADAM12 overexpression enhanced proliferation, inhibited apoptosis, and acted as a positive regulator of cell cycle progression in CRC cells. Phosphorylation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was decreased and that of Akt was increased by ADAM12 overexpression. These results were reversed upon ADAM12 knockdown. ADAM12 overexpression was significantly associated with the cancer stage, depth of invasion, lymph node metastasis, distant metastasis, and poor survival in CRC patients. In a mouse xenograft model, tumor area, volume, and weight were significantly greater for the ADAM12 overexpression group and significantly lower for the ADAM12 knockdown group. In conclusion, ADAM12 may serve as a promising biomarker and/or therapeutic target in CRC.

Abstract

A disintegrin and metalloprotease 12 (ADAM12) has been implicated in cell growth, tumor formation, and metastasis. Therefore, we evaluated the role of ADAM12 in colorectal cancer (CRC) progression and prognosis, and elucidated whether targeted downregulation of ADAM12 could lead to therapeutic sensitization. The effect of ADAM12 on tumor cell behavior was assessed in CRC cell lines, CRC tissues, and a mouse xenograft model. ADAM12 overexpression enhanced proliferation, inhibited apoptosis, and acted as positive regulator of cell cycle progression in CRC cells. Phosphorylation of PTEN was decreased and that of Akt was increased by ADAM12 overexpression. These results were reversed upon ADAM12 knockdown. ADAM12 overexpression was significantly associated with the cancer stage, depth of invasion, lymph node metastasis, distant metastasis, and poor survival in CRC patients. In a mouse xenograft model, tumor area, volume, and weight were significantly greater for the ADAM12-pcDNA6-myc-transfected group than for the empty-pcDNA6-myc-transfected group, and significantly lower for the ADAM12-pGFP-C-shLenti-transfected group than for the scrambled pGFP-C-shLenti-transfected group. In conclusion, ADAM12 overexpression is essential for the growth and progression of CRC. Furthermore, ADAM12 knockdown reveals potent anti-tumor activity in a mouse xenograft model. Thus, ADAM12 may serve as a promising biomarker and/or therapeutic target in CRC.

Identifying and revealing the geographical variation in Nemopilema nomurai venom metalloprotease and phospholipase A2 activities

Venom geographical variation is common among venomous animals. This phenomenon presents problems in the development of clinical treatments and medicines against envenomation. The venomous giant jellyfish Nemopilema nomurai, Scyphozoan, is a blooming jellyfish species in the Yellow Sea and the East China Sea that causes numerous jellyfish sting cases every year. Metalloprotease and phospholipase A₂ (PLA₂) are the main components in Nemopilema nomurai venom and may activate many toxicities, such as hemolysis, inflammation and lethality. Geographical variation in the content and activity of these enzymes may cause different symptoms and therapeutic problems. For the first time, we verified metalloprotease and PLA₂ geographical variation in Nemopilema nomurai venom by performing a comparative analysis of 31 venom samples by SDS-PAGE, analyzing protease zymography, enzymatic activity, and drawing contour maps. Band locations and intensities of SDS-PAGE and protease zymograms showed geographical differences. The enzymatic activities of both metalloprotease and PLA₂ showed a trend of geographic regularity. The distribution patterns of these activities are directly shown in contour maps. Metalloproteinase activity was lower near the coast. PLA₂-like activity was lower in the Southern Yellow Sea. We surmised that metalloproteinase and PLA₂-like activities might be related to venom ontogeny and species abundance respectively, and influenced by similar environmental factors. This study provides a theoretical basis for further ecological and medical studies of Nemopilema nomurai jellyfish venom.

Can the expression of the metalloproteinase 9 gene and its inhibitor be considered as markers of heart failure?

BACKGROUND

Heart failure (HF) is a major cause of mortality in developed countries. Its formation is associated with a change in the transcriptional activity of many genes. The aim of the study was to select, from the group of genes related to coronary atherosclerosis and heart failure, genes differentiating patients with coronary heart disease and heart failure on the basis of myocardial ischemia from healthy people, and then genes differentiating patients with various stages of heart failure.

METHODS

The study was carried out using the oligonucleotide microarray technique HG-U133A (Affymetrix, Santa Clara, CA, USA). Cluster analysis showed a homogeneous division of the study group into patients with heart failure and healthy patients with excluded coronary artery disease and patients with heart failure depending on the size of the left ventricle ejection fraction.

RESULTS

The study showed that genes differentiating the group of patients from healthy people were: TGF-β1, TIMP-1 and MMP-9. The analysis also showed that genes differentiated patients with advanced heart failure in the course of coronary disease and left ventricular ejection fraction (LVEF) 20% and patients from the group with 40% LVEF were MMP-9 and TIMP-1.

CONCLUSIONS

Extracting from the group of genes related to coronary atherosclerosis and cardiac failure: MMP-9, TGF-β1 and TIMP-1 differentiating patients with heart failure on the basis of myocardial ischemia in varying degrees of severity from healthy people may indicate their significant contribution to disease development. Also increased expression of the metalloproteinase gene 9 (MMP-9) with a simultaneous decrease in the expression of its tissue inhibitor 1 (TIMP-1) in the studied group of patients with ischemic heart failure differing in left ventricular ejection fraction LVEF makes them the markers of progression in failure.

Proteomic Analysis of Human Blister Fluids Following Envenomation by Three Snake Species in India: Differential Markers for Venom Mechanisms of Action

Skin blistering as a result of snakebite envenomation is characteristic of some bites, however little is known regarding the mechanism of blister formation or the composition of the blister fluid. In order to investigate if blister fluid proteomes from humans suffering snakebite envenomation could provide insights on the pathophysiology of these skin alterations, blister fluid was collected from six patients upon presentation at a clinic in India bitten by three species of snakes, Daboia russelii (3), Hypnale hypnale (2), or Naja naja (1). Standard clinical data were recorded throughout the treatment. Approximately 805 proteins were identified in blister fluids using proteomic analyses. Informatics analyses of the proteomes identified the top biological response categories as: platelet degranulation, innate immune response, receptor-mediated endocytosis, complement activation, and blood coagulation. Hierarchical clustering did not show a clear segregation of patients' proteomes being associated with the species of snake involved, suggesting that either the proteomic profiles described reflect a general response to venom-induced tissue damage or more patient data sets will be required to observe significant differences. Finally, it is of interest that venom proteins were also identified in the blister fluids suggesting that this fluid may serve as a reservoir of venom biologically active proteins/toxins, and as such, may indicate the clinical value of removing blister fluid to attenuate further tissue damage.