TACE/ADAM17 substrates associate with ACS (Ep-CAM, HB-EGF) and follow-up MACE (TNFR1 and TNFR2).

Background and aims: TACE/ADAM17 is a membrane bound metalloprotease, which cleaves substrates involved in immune and inflammatory responses and plays a role in coronary artery disease (CAD). We measured TACE and its substrates in CAD patients to identify potential biomarkers within this molecular pathway with potential for acute coronary syndrome (ACS) and major adverse cardiovascular events (MACE) prediction. Methods: Blood samples were obtained from consecutive patients (n = 229) with coronary angiographic evidence of CAD admitted with ACS or electively. MACE were recorded after a median 3-year follow-up. Controls (n = 115) had a <10% CAD risk as per the HeartSCORE. TACE and TIMP3 protein and mRNA levels were measured by ELISA and RT-qPCR respectively. TACE substrates were measured using a multiplex proximity extension assay. Results: TACE mRNA and cell protein levels (p < 0.01) and TACE substrates LDLR (p = 0.006), TRANCE (p = 0.045), LAG-3 (p < 0.001) and ACE2 (p < 0.001) plasma levels were significantly higher in CAD patients versus controls. TACE inhibitor TIMP3 mRNA levels were significantly lower in CAD patients and tended to be lower in the ACS population (p < 0.05). TACE substrates TNFR1 (OR:3.237,CI:1.514-6.923,p = 0.002), HB-EGF (OR:0.484,CI:0.288-0.813,p = 0.006) and Ep-CAM (OR:0.555,CI:0.327-0.829,p = 0.004) accurately classified ACS patients with HB-EGF and Ep-CAM levels being lower compared to electively admitted patients. TNFR1 (OR:2.317,CI:1.377-3.898,p = 0.002) and TNFR2 (OR:1.902,CI:1.072-3.373,p = 0.028) were significantly higher on admission in those patients who developed MACE within 3 years. Conclusions: We demonstrate a possible role of TACE substrates LAG-3, HB-EGF and Ep-CAM in atherosclerotic plaque development and stability. We also underline the importance of measuring TNFR1 and TNFR2 earlier than previously appreciated for MACE prediction. We report an important role of TIMP3 in regulating TACE levels.

A hybrid computational approach for efficient Alzheimer's disease classification based on heterogeneous data.

There is currently a lack of an efficient, objective and systemic approach towards the classification of Alzheimer's disease (AD), due to its complex etiology and pathogenesis. As AD is inherently dynamic, it is also not clear how the relationships among AD indicators vary over time. To address these issues, we propose a hybrid computational approach for AD classification and evaluate it on the heterogeneous longitudinal AIBL dataset. Specifically, using clinical dementia rating as an index of AD severity, the most important indicators (mini-mental state examination, logical memory recall, grey matter and cerebrospinal volumes from MRI and active voxels from PiB-PET brain scans, ApoE, and age) can be automatically identified from parallel data mining algorithms. In this work, Bayesian network modelling across different time points is used to identify and visualize time-varying relationships among the significant features, and importantly, in an efficient way using only coarse-grained data. Crucially, our approach suggests key data features and their appropriate combinations that are relevant for AD severity classification with high accuracy. Overall, our study provides insights into AD developments and demonstrates the potential of our approach in supporting efficient AD diagnosis.

A combined mass spectrometric and cDNA sequencing approach to the isolation and characterization of novel antimicrobial peptides from the skin secretions of Phyllomedusa hypochondrialis azurea.

Studies conducted on amphibian skin secretions over the past 40 years have isolated and identified huge arrays of bioactive peptides, many of which have demonstrated potent anti-microbial activity. Such peptides are attracting increasing attention due to the growing problem of pathogenic microorganisms resistant to conventional antibiotics. The current study utilized a combined proteomic/genomic approach to facilitate the high throughput sequencing of five novel dermaseptins and four novel phylloseptins from the skin secretions of Phyllomedusa hypochondrialis azurea. Peptides were partially identified using Q-TOF MS/MS fragmentation and de novo sequencing, while a cDNA library was constructed from the lyophilized skin secretion. 3'-RACE reactions used primers designed for the highly conserved 5'-signal regions of previously deduced dermaseptin precursors. cDNA sequenced peptides were attributed to their respective fragmentation spectra to confirm the structure of the final processed peptides. Such an approach identified post-translational modifications in addition to deciphering isobaric amino acids. Several of the peptides were purified to homogeneity and displayed potent antimicrobial activity with minimum inhibitory concentrations starting at 0.4 microM when tested against and range of Gram-positive and Gram-negative bacteria including Escherichia coli, Staphylococcus aureus and Micrococcus luteus.

Role of tumour necrosis factor alpha converting enzyme (TACE/ADAM17) and associated proteins in coronary artery disease and cardiac events.

Tumour necrosis factor alpha converting enzyme (TACE/ADAM17) is a member of the A disintegrin and metalloproteinase (ADAM) family of ectodomain shedding proteinases. It regulates many inflammatory processes by cleaving several transmembrane proteins, including tumour necrosis factor alpha (TNFα) and its receptors tumour necrosis factor alpha receptor 1 and tumour necrosis factor alpha receptor 2. There is evidence that TACE is involved in several inflammatory diseases, such as ischaemia, heart failure, arthritis, atherosclerosis, diabetes and cancer as well as neurological and immune diseases. This review summarizes the latest discoveries regarding the mechanism of action and regulation of TACE. It also focuses on the role of TACE in atherosclerosis and coronary artery disease (CAD), highlighting clinical studies that have investigated its expression and protein activity. The multitude of substrates cleaved by TACE make this enzyme an attractive target for therapy and a candidate for biomarker research and development in CAD.

Amphibian skin secretomics: application of parallel quadrupole time-of-flight mass spectrometry and peptide precursor cDNA cloning to rapidly characterize the skin secretory peptidome of Phyllomedusa hypochondrialis azurea: discovery of a novel peptide family, the hyposins.

This study reports the variety of peptides present in the skin secretory peptidome of Phyllomedusa hypochondrialis azurea. Peptide structures, along with post-translational modifications, were elucidated by QTOF MS/MS analysis, cDNA sequencing, or a combination of both. Twenty-two peptides, including 19 novel structures, were identified from six different structural classes, including tryptophyllins, dermorphins, and a novel group of peptides termed hyposins. The study demonstrates the power of this combined approach to mine the rich peptidome compliment of the amphibian defensive skin secretome.

Bradykinin-related peptides from Phyllomedusa hypochondrialis azurea: Mass spectrometric structural characterisation and cloning of precursor cDNAs.

Amphibian skin secretions contain a plethora of bioactive compounds, many of which are understood to act to deter ingestion by predators. Bradykinins in particular are constitutively expressed in many amphibian skin secretions, mediating a variety of effects including hyperalgesia and contraction of gastric smooth muscle. Using a variety of proteomic techniques (high-performance liquid chromatography (HPLC) separation, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS), and quadrupole time-of-flight tandem mass spectrometry (Q-TOF-MS/MS)) the current study identified 13 bradykinin-like peptides in the skin secretions of Phyllomedusa hypochondrialis azurea, including several new C-terminally extended isoforms (VPPGFTPFRLT, VHypPGFTPFRQT) and a novel phyllokinin-like peptide (RPPGFTPFRVY). Identification of the cDNA sequences encoding these peptides led to the deduction that the peptides were derived from differential post-translational processing and modification of five different precursors. Such an event emphasises the metabolic efficiency of peptide production in amphibian venom, with multiple products perhaps selective to different receptors in a variety of predators generated from a single precursor. An unusual modification was also recognised in the present study, with several bradykinin-like peptides featuring hydroxyprolination of the first proline residue rather than the commonly targeted second. This alteration may be mediated by the structural organisation of N-terminal amino acids prior to precursor processing.