Ian Pike

Tubulin β-III: a novel immunohistochemical marker for intrahepatic peripheral cholangiocarcinoma

Our recent proteomic study identified tubulin β‐III (TUBB3) as a potential tissue marker for intrahepatic cholangiocarcinomas (CCs). This validation study was conducted to see whether or not TUBB3 can serve as a novel immunohistochemical marker for peripheral CCs, using a large cohort (n = 197) covering various liver tumours and premalignant conditions.

Comprehensive Quantitative Profiling of Tau and Phosphorylated Tau Peptides in Cerebrospinal Fluid by Mass Spectrometry Provides New Biomarker Candidates

Aberrant tau phosphorylation is a hallmark in Alzheimers disease (AD), believed to promote formation of paired helical filaments, the main constituent of neurofibrillary tangles in the brain. While cerebrospinal fluid (CSF) levels of total tau and tau phosphorylated at threonine residue 181 (pThr181) are established core biomarkers for AD, the value of alternative phosphorylation sites, which may have more direct relevance to pathology, for early diagnosis is not yet known, largely due to their low levels in CSF and lack of standardized detection methods. To overcome sensitivity limitations for analysis of phosphorylated tau in CSF, we have applied an innovative mass spectrometry (MS) workflow, TMTcalibratortrademark, to enrich and enhance the detection of phosphoproteome components of AD brain tissue in CSF, and enable the quantitation of these analytes. We aimed to identify which tau species present in the AD brain are also detectable in CSF and which, if any, are differentially regulated with disease. Over 75% coverage of full-length (2N4R) tau was detected in the CSF with 47 phosphopeptides covering 31 different phosphorylation sites. Of these, 11 phosphopeptides were upregulated by at least 40%, along with an overall increase in tau levels in the CSF of AD patients relative to controls. Use of the TMTcalibratortrademark workflow dramatically improved our ability to detect tau-derived peptides that are directly related to human AD pathology. Further validation of regulated tau peptides as early biomarkers of AD is warranted and is currently being undertaken.

Proteomics Testing for Sensitization Potency Using the Sensiderm™ TMT-SRM 10-Plex Assay

Along with the rise in the use chemical allergens in in fragrances and cosmetic products, increased reporting of allergic contact dermatitis (ACD) continues to be a public health concern. So far, risk assessment of potential allergens essentially relies upon animal testing. New proteomics technologies combined with appropriate cell culture models and bioinformatics tools open up the window to transfer logical pathway information into biomarker assays. Sensiderm™ TMT-SRM 10-plex is a multiparametric assay, which is based on the established principles of selected reaction monitoring (SRM) mass spectrometry. The assay uses the human dendritic model MUTZ-3 exposed to chemical sensitizers to measure a response signature of ten proteins. In a model-building phase, the ten protein targets were initially discovered using a set of chemical sensitizers provided by the European Integrated Project Sens-it-iv. Currently, the Sensiderm assay has been pre-validated in two analytical laboratories, and a set of testing chemicals has been investigated in both non-blinded and blinded manner. In summary, the Sensiderm 10-plex assay reflects the activation of different sensitization-related pathways. A proper interpretation of this information may be integrated in decision-making processes of suspicious chemicals.

Predicting the progression of Alzheimer's disease by plasma-based biomarkers

Background: Alzheimer’s disease (AD) is the most common form of dementia, at present there remains a need for accurate biomarkers that can predict disease progression. In recent years markers of prediction, early diagnosis and progression have been identified in plasma by our group. We have therefore selected a multiplexing approach using the immunobased MILLIPLEX MAP assays to validate our previously discovered biomarkers with the aim to identify a combination of markers that can predict disease progression. Methods: 430 Alzheimer’s disease subjects, 395 cognitively normal and 173 mild cognitively impairment subjects were recruited from 2 large multi-centre cohorts. EDTA plasma was collected and evaluated for 45 analytes, using immuno-based MILLIPLEX MAP assays. Samples were randomized, blinded to the clinical information and measured in duplicate. Results: The intra-assay precision was calculated as the coefficient of variation (%) for each analyte and was <10% across the 45 analytes. The inter-assay precision was <15% for 40 out of the 45 analytes. The results from our study have identified 32 analytes that significantly correlate with changes in Clinical Dementia Rating (CDR), minimental state examination (MMSE), Alzheimer’s disease Assessment Scale-Cognitive Subscale (ADAS-cog) and Global Detoriation Scale (GDS) in our Alzheimer’s disease subjects. This univariate analysis will be followed by multivariate analysis to identify which combination of analytes may be able to predict disease progression. Conclusions: Plasma-based biomarkers have the potential to successfully predict disease progression. Results from previous studies along with this qualification study, strengthen the notion that multiplexing plasma biomarkers improve accuracy and may have a useful clinical application.