ADAMTS7 Antibody

What is ADAMTS7 and why is it significant in cardiovascular research?

ADAMTS7 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 7) is an extracellular matrix (ECM) protease that has been genome-wide significantly associated with coronary artery disease (CAD) . Research has demonstrated that lack of ADAMTS-7 reduces atherosclerotic plaque formation, establishing it as a critical protein in the pathogenesis of atherosclerosis . The significance of ADAMTS7 is highlighted by studies showing its expression is higher in caps of unstable carotid plaques compared to stable plaques, suggesting a role in plaque instability . Additionally, ADAMTS7's ability to degrade extracellular matrix components and influence vascular smooth muscle cell migration positions it as a potential therapeutic target for atherosclerotic disease .

What are the recommended methods for validating ADAMTS7 antibody specificity?

Validating ADAMTS7 antibody specificity requires multiple complementary approaches. Primary validation should include Western blotting using protein lysates from cells overexpressing ADAMTS7 compared to control lysates, as demonstrated in studies examining ADAMTS7-V5 and TIMP-1-HA constructs . Researchers should also perform immunoprecipitation followed by mass spectrometry to confirm antibody specificity and identify potential cross-reactivity .

For tissue analysis, immunohistochemistry or immunofluorescence should be performed on both wildtype and knockout tissue samples (such as from Apoe−/−Adamts7−/− mice) to validate antibody specificity in physiological contexts . When analyzing antibody specificity, attention should be paid to detecting the proper molecular weight bands, as ADAMTS7 undergoes post-translational modifications including glycosylation . Analysis of known ADAMTS7 domains (catalytic domain, disintegrin-like domain, and thrombospondin repeats) can provide additional specificity confirmation .

How should researchers utilize ADAMTS7 antibodies in immunoblotting experiments?

When performing immunoblotting with ADAMTS7 antibodies, researchers should follow these methodological considerations:

• Sample preparation: Protein extraction from tissues (such as atherosclerotic aortas) should be performed with buffers containing protease inhibitors to prevent degradation of ADAMTS7 .

• Protein separation: Use appropriate percentage gels (typically 7.5-10% SDS-PAGE) to effectively resolve ADAMTS7 (approximately 180 kDa full-length protein) .

• Transfer conditions: Due to the relatively large size of ADAMTS7, extended transfer times or semi-dry transfer systems are recommended for efficient transfer to membranes .

• Blocking: Use 5% non-fat dry milk or BSA in TBS-T for blocking, depending on the antibody manufacturer's recommendations.

• Antibody dilution: Optimal dilutions should be determined empirically, but typically range from 1:500 to 1:2000 for primary antibodies against ADAMTS7 .

• Detection system: For quantitative analysis, fluorescence-based detection systems such as the ImageQuant 800 imaging system provide superior linearity compared to chemiluminescence .

• Controls: Include positive controls (ADAMTS7-overexpressing cells) and negative controls (knockout models or siRNA-treated samples) to validate specificity .

Quantification should be performed using software such as ImageJ, normalizing to loading controls such as β-actin or GAPDH .

What experimental applications are most suitable for ADAMTS7 antibodies?

ADAMTS7 antibodies have demonstrated utility in numerous experimental applications:

For most accurate results, researchers should validate antibodies in each specific application before proceeding with experimental work .

What are the differences between polyclonal and monoclonal ADAMTS7 antibodies in research applications?

Polyclonal and monoclonal ADAMTS7 antibodies offer different advantages depending on the research application:

Polyclonal ADAMTS7 antibodies:

• Recognize multiple epitopes, increasing detection sensitivity

• Useful for detecting low abundance ADAMTS7 in tissues or primary cells

• Better for immunoprecipitation of native proteins

• May show batch-to-batch variation requiring validation

• Suitable for initial characterization studies of ADAMTS7 expression

Monoclonal ADAMTS7 antibodies:

• Recognize single epitopes, providing higher specificity

• Consistent performance across experiments with minimal batch variation

• Preferable for quantitative applications and comparative studies

• May have reduced sensitivity compared to polyclonal antibodies

• Essential for distinguishing specific domains of ADAMTS7 (catalytic domain vs. thrombospondin repeats)

When designing experiments to study ADAMTS7-TIMP-1 interactions or domain-specific functions, monoclonal antibodies targeting specific domains offer advantages for mapping protein-protein interaction sites .

How can researchers use ADAMTS7 antibodies to study protein-protein interactions with TIMP-1?

Investigating ADAMTS7-TIMP-1 interactions requires several sophisticated antibody-based approaches:

• Co-immunoprecipitation (Co-IP): Researchers should use epitope-tagged constructs (ADAMTS7-V5, TIMP-1-HA) for initial validation of interactions . For endogenous interactions, use ADAMTS7 antibodies to immunoprecipitate protein complexes from vascular smooth muscle cells or atherosclerotic tissue lysates, followed by immunoblotting for TIMP-1 .

• Domain mapping: Create deletion constructs of ADAMTS7 lacking specific domains (e.g., ΔTSPrADAMTS7-V5 and ΔcatADAMTS7-V5) to determine binding sites through Co-IP experiments . Research has demonstrated that TIMP-1 binds to the catalytic domain of ADAMTS7, unlike other ADAMTS7 targets such as TSP-1 and COMP that bind to C-terminal thrombospondin repeats .

• FRET-based assays: For quantitative analysis of protein interactions, develop time-resolved FRET assays using ADAMTS7-FLAG and TIMP-1-HA constructs . This approach requires:

  • Overexpression of tagged proteins in HEK293 cells

  • Incubation of protein lysates with fluorophore-conjugated antibodies (anti-FLAG-cryptate and anti-HA-d2)

  • Excitation at 337 nm and measurement of emission at both 620 nm and 665 nm

  • Calculation of FRET ratio (665/620 nm) as primary readout

• Competition assays: To validate specificity and screen for inhibitors, perform competition assays with untagged recombinant TIMP-1, which should produce dose-dependent decreases in FRET signal . Research has shown that untagged TIMP-1 at 800 ng reduced the FRET signal from 4954±197.5 to 3571±143.8 (665/620 ratio, P value for trend=2×10−4) .

These methodologies provide a comprehensive approach to characterizing the ADAMTS7-TIMP-1 interaction, which has implications for understanding atherosclerosis pathogenesis and developing potential therapeutic interventions .

How can ADAMTS7 antibodies be used to evaluate differential expression in stable versus unstable atherosclerotic plaques?

Analysis of ADAMTS7 expression in different plaque phenotypes requires specific methodological approaches:

• Tissue microdissection: For human samples, researchers should carefully isolate fibrous caps from both stable and unstable carotid plaques, as demonstrated in studies from the Munich Vascular Biobank . This requires precise microdissection techniques to separate the cap from the necrotic core.

• RNA expression analysis: For mRNA quantification, use real-time RT-PCR with ADAMTS7-specific primers. Normalization should be performed against stable housekeeping genes (such as GAPDH or β-actin) . Research has demonstrated that ADAMTS7 mRNA levels are significantly higher in caps of unstable plaques (stable plaques: median, 0.22; interquartile range, 0.16–0.63 versus unstable plaques: median, 1.29; interquartile range, 0.66–2.25 [2−ΔCt]; P=5×10−4) .

• Protein expression analysis: For protein-level assessment, immunohistochemistry or immunofluorescence using validated ADAMTS7 antibodies should be performed on serial sections of plaque specimens . Quantification of staining intensity and distribution should be conducted using digital image analysis software.

• Co-localization studies: Double immunofluorescence staining with ADAMTS7 antibodies and markers of plaque instability (such as CD68 for macrophages, MMP-9, or markers of intraplaque hemorrhage) can provide insights into the spatial relationship between ADAMTS7 expression and plaque vulnerability features .

• Validation in animal models: To complement human studies, researchers can induce plaque destabilization in mouse models (such as Apoe−/− mice) through tandem stenosis or collar placement and analyze ADAMTS7 expression in stable versus vulnerable plaque regions .

These approaches allow researchers to establish the relationship between ADAMTS7 expression and plaque stability, which has potential implications for using ADAMTS7 as a biomarker for plaque vulnerability .

What methodology should be employed to develop FRET-based screening assays for ADAMTS7 inhibitors using specific antibodies?

Developing FRET-based screening assays for ADAMTS7 inhibitors requires careful optimization:

• Construct design and expression: Generate epitope-tagged constructs (ADAMTS7-FLAG and TIMP-1-HA) and express them in appropriate cell lines (e.g., HEK293) . For the ADAMTS7 construct, researchers should include the catalytic domain, which has been shown to interact with TIMP-1 .

• FRET pair selection: Use fluorophore-conjugated antibodies that form efficient FRET pairs, such as anti-FLAG-cryptate (donor) and anti-HA-d2 (acceptor) . The excitation wavelength should be 337 nm for cryptate, with emission measured at 620 nm (donor) and 665 nm (acceptor) .

• Assay optimization:

  • Determine optimal protein expression levels

  • Titrate antibody concentrations

  • Establish protein-protein interaction baselines

  • Test signal stability over time

• Validation of specificity:

  • Include negative controls (mock plasmid + TIMP-1-HA, ADAMTS7-FLAG + mock)

  • Test constructs lacking the catalytic domain of ADAMTS7 (ΔcatADAMTS7)

  • Perform competition assays with untagged recombinant proteins

• Assay miniaturization and automation: Adapt the protocol to 384-well or 1536-well format for high-throughput screening applications.

• Screening methodology:

  • Calculate FRET ratio (665/620 nm) as primary readout

  • Set threshold values based on positive and negative controls

  • Include dose-response testing for hit confirmation

Research has demonstrated that this approach can detect protein-protein interactions with high sensitivity (ADAMTS-7-FLAG+TIMP-1-HA 5484±302.9 versus mock+TIMP-1-HA 369.5±142.2, P=6.9×10−10) , and the competition assay with untagged TIMP-1 shows dose-dependent signal reduction suitable for inhibitor screening .

How can ADAMTS7 antibodies be utilized to evaluate the efficacy of ADAMTS7-targeting vaccines?

Evaluating ADAMTS7-targeting vaccines requires comprehensive antibody-based approaches:

• Antibody response characterization: Use ELISA with recombinant ADAMTS7 or peptide epitopes to quantify vaccine-induced antibody titers in animal models . Research has shown successful immunization with peptide vaccines conjugated to KLH (keyhole limpet hemocyanin) carrier protein .

• Antibody specificity testing: Employ competitive binding assays and epitope mapping to ensure antibodies target the intended ADAMTS7 epitopes, typically within functional domains .

• Functional neutralization assays:

  • In vitro assessment of vaccine-induced antibodies to inhibit ADAMTS7-mediated COMP (cartilage oligomeric matrix protein) and TSP-1 (thrombospondin-1) degradation

  • Evaluation of antibody effects on vascular smooth muscle cell migration

  • Analysis of re-endothelialization processes

• Tissue-level evaluation: Use immunohistochemistry with ADAMTS7 antibodies to assess:

  • Atherosclerotic plaque formation in ApoE−/− and LDLR−/− mice

  • Neointima formation in arterial injury models

  • In-stent restenosis in larger animal models (e.g., Bama miniature pigs)

• Mechanistic verification: Apply Western blotting to evaluate downstream molecular targets affected by vaccine-induced antibodies, such as COMP and TSP-1 degradation products .

Research has demonstrated that effective ADAMTS7 vaccines (such as ATS7vac) can inhibit intimal thickening in murine models, alleviate neointima formation after vascular injury, and mitigate atherosclerotic lesions in hyperlipidemic mice without altering lipid levels .

What methodological approaches can resolve contradictory results when using different ADAMTS7 antibodies?

When faced with contradictory results using different ADAMTS7 antibodies, researchers should implement the following systematic approach:

• Epitope mapping: Determine the exact epitopes recognized by each antibody to understand if they target different domains of ADAMTS7 (catalytic domain, disintegrin-like domain, or thrombospondin repeats) . Different functional domains may show varying expression patterns or accessibility in different experimental contexts.

• Validation panel: Establish a comprehensive validation panel including:

  • Western blotting with recombinant ADAMTS7 and tissue lysates

  • Immunoprecipitation followed by mass spectrometry

  • Use of ADAMTS7 knockout tissues as negative controls

  • Testing antibodies on domain deletion mutants

• Cross-validation with orthogonal methods:

  • Compare protein detection results with mRNA expression (RT-qPCR)

  • Use epitope-tagged ADAMTS7 constructs detected with tag-specific antibodies

  • Employ proteomics approaches for unbiased protein identification

• Technical optimization:

  • Test different sample preparation methods (native vs. denaturing conditions)

  • Optimize antigen retrieval protocols for tissue sections

  • Evaluate fixation methods that may affect epitope accessibility

• Post-translational modification analysis: Determine if contradictory results stem from antibodies differentially recognizing modified forms of ADAMTS7, using:

  • Enzymatic deglycosylation treatments

  • Phosphatase treatments

  • Mass spectrometry to identify modified residues

This systematic approach can help reconcile contradictory findings and provide a more complete understanding of ADAMTS7 biology in different experimental contexts .

How can researchers employ ADAMTS7 antibodies to study its role in collagen degradation and plaque stability?

Investigating ADAMTS7's role in collagen degradation and plaque stability requires specific methodological approaches:

• Collagen content assessment: Use Picrosirius red staining of atherosclerotic plaques from control and ADAMTS7-deficient models (e.g., Apoe−/− vs. Apoe−/−Adamts7−/− mice) to quantify collagen content as a readout of MMP-9 activity . This histological approach should be coupled with polarized light microscopy to differentiate collagen fiber types.

• In situ zymography: Apply fluorescein-conjugated gelatin substrates to tissue sections to directly visualize areas of collagenase/gelatinase activity, correlating with ADAMTS7 expression through immunofluorescence on serial sections .

• Ex vivo matrix degradation assays:

  • Use fluorescein-conjugated gelatin assays with supernatants from cells overexpressing ADAMTS7 or control plasmids

  • Perform gel zymography to identify specific matrix metalloproteinases activated downstream of ADAMTS7

  • Conduct colorimetric assays with recombinant MMP-9 added to concentrated supernatants from cells expressing ADAMTS7 and TIMP-1

• Mechanistic pathway analysis:

  • Investigate the ADAMTS7-TIMP-1-MMP-9 axis through sequential knockdown or inhibition experiments

  • Quantify TIMP-1 protein levels in atherosclerotic tissue from Apoe−/− and Apoe−/−Adamts7−/− mice using immunoblotting

  • Perform coimmunoprecipitation experiments to demonstrate binding between the catalytic domain of ADAMTS7 and TIMP-1

• Functional consequences assessment:

  • Evaluate plaque vulnerability features in mouse models with differential ADAMTS7 expression

  • Correlate ADAMTS7 expression with markers of plaque instability in human samples

  • Perform biomechanical testing of plaque tensile strength in relation to ADAMTS7 expression

Research has demonstrated that ADAMTS7 reduces the inhibitory capacity of TIMP-1 on MMP-9, leading to increased MMP-9 activity and reduced collagen content in atherosclerotic plaques . This mechanism provides insight into how ADAMTS7 may influence plaque stability and potential therapeutic targets.

What are the emerging applications of ADAMTS7 antibodies in cardiovascular research?

ADAMTS7 antibodies are increasingly being utilized in novel research directions with significant therapeutic implications:

• Biomarker development: ADAMTS7 antibodies are being explored for developing immunoassays to detect circulating ADAMTS7 as a potential biomarker for plaque instability and cardiovascular risk stratification . The higher expression of ADAMTS7 in unstable versus stable plaques provides a rationale for this application .

• Therapeutic antibody development: Based on vaccine research showing efficacy of induced anti-ADAMTS7 antibodies , therapeutic monoclonal antibodies against ADAMTS7 are being explored as potential treatments for atherosclerosis and restenosis.

• Imaging applications: Development of labeled ADAMTS7 antibodies or antibody fragments for molecular imaging of atherosclerotic plaques could enable non-invasive assessment of plaque vulnerability in vivo.

• Precision medicine approaches: ADAMTS7 antibodies may help identify patient subgroups with high ADAMTS7 activity who might benefit from targeted therapies, especially given the genetic association of ADAMTS7 variants with coronary artery disease .

• Drug discovery platforms: High-throughput screening systems using FRET-based assays with ADAMTS7 antibodies are facilitating the identification of small molecule inhibitors of ADAMTS7-TIMP-1 interactions .