ADAMTS13
A disintegrin and metalloproteinase with thrombospondin motifs 13 precursor (EC 3.4.24.87) (ADAM-TS 13) (ADAM-TS13) (ADAMTS-13) (von Willebrand factor-cleaving protease) (vWF-CP) (vWF-cleaving protease) [C9orf8] [UNQ6102/PRO20085]
PublicationsПравить
Corpora amylacea (CA) have long been described in aging brains and in patients with neurodegenerative conditions, but their origins have been debated. It has been proposed that CA represent collections of nervous system breakdown products that accumulate within astrocytic cytoplasm. In support of this, studies have shown that CA include glycosylated material, ubiquitin, and an assortment of proteins derived from neuronal cytoplasm. On the other hand, many of these proteins are not specifically localized to neurons or astrocytes; some components of CA, such as complement proteins, are most abundantly expressed outside the central nervous system. The characteristic predilection for CA to accumulate near vessels and ependyma suggests that proteins extravasated from blood or transudated from CSF may form a component of these structures. In this study, we report the immunohistochemical localization of blood and platelet proteins thrombospondin1 and ADAMTS13 in CA from aged individuals and patients with vascular dementia. Thrombospondin1 localized to neurons, but was most prominently localized to CA. An independent serum and platelet expressed protein, ADAMTS13, was found in CA in the same brain regions. In vitro analysis shows that thrombospondin1 and ADAMTS13 form complexes together in cells and in direct protein binding assays. We speculate that CA could result from a conglomeration of interacting proteins from degenerating neurons and from extravasated blood elements released after transient breakdown of the blood-brain barrier.
MeSH Terms
- ADAM Proteins
- ADAMTS13 Protein
- Aged
- Aged, 80 and over
- Aging
- Astrocytes
- Brain
- Dementia, Vascular
- Female
- Humans
- Immunohistochemistry
- Immunoprecipitation
- Inclusion Bodies
- Male
- Middle Aged
- Neurons
- Thrombospondin 1
A plasma metalloprotease, ADAMTS13, cleaves von Willebrand factor (VWF) multimers and downregulates their activity in platelet aggregation. Functional ADAMTS13 deficiency leads to the accumulation of hyperactive large VWF multimers, inducing a life-threatening disease, thrombotic thrombocytopenic purpura (TTP). Although measuring ADAMTS13 activity is important in TTP diagnosis, existing methods require time and skill. Here, we report a fluorescence resonance energy transfer (FRET) assay for ADAMTS13 activity. We developed a synthetic 73-amino-acid peptide, FRETS-VWF73. Cleavage of this substrate between two modified residues relieves the fluorescence quenching in the intact peptide. Incubation of FRETS-VWF73 with normal human plasma quantitatively increased fluorescence over time, while ADAMTS13-deficient plasma had no effect. Quantitative analysis could be achieved within a 1-h period using a 96-well format in commercial plate readers with common filters. The FRETS-VWF73 assay will be useful for the characterization of thrombotic microangiopathies like TTP and may clarify the importance of ADAMTS13 activity as a predictive marker for various thrombotic diseases.
MeSH Terms
- ADAM Proteins
- ADAMTS13 Protein
- Adult
- Aged
- Aged, 80 and over
- Aging
- Biomarkers
- Female
- Fluorescence Resonance Energy Transfer
- Fluorescent Dyes
- Humans
- Indicators and Reagents
- Male
- Metalloendopeptidases
- Middle Aged
- Purpura, Thrombotic Thrombocytopenic
- Recombinant Proteins
- Reference Values
- Reproducibility of Results
- Sex Characteristics