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Antibody-free quantification of seven tau peptides in human CSF using targeted mass spectrometry.

Bros P, Vialaret J, Barthelemy N, Delatour V, Gabelle A, Lehmann S, Hirtz C - Front Neurosci (2015)

Bottom Line: Quantification was performed using isotopically labeled (15)N- recombinant tau protein as internal standard and validated using CSF pools with low, medium, or high tau concentrations (HTCs).Repeatability, intermediate precision, linearity, limit of quantification (LOQ), and recovery were calculated for the different peptides.This new MRM assay, which allowed for the first time CSF tau protein quantification without immunocapture, has important potential application to follow tau metabolism in both diagnostic and therapeutic research.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Biochimie et de Protéomique Clinique - Institut de Médecine Régénérative et Biothérapies, Centre Hospitalier Universitaire de Montpellier Montpellier, France ; Laboratoire National de Métrologie et d'Essais (LNE) Paris, France.

ABSTRACT
Tau protein concentration in cerebrospinal fluid (CSF) is currently used as a sensitive and specific biomarker for Alzheimer's disease. Its detection currently relies on ELISA but the perspective of using mass spectrometry (MS) to detect its different proteoforms represents an interesting alternative. This is however an analytical challenge because of its low concentration in the CSF, a biological fluid collected in small volume by lumbar puncture, and with a high structural heterogeneity. To overcome these issues, instead of using immunocapture as previously done, we rather relied on an original two steps pre-fractionation technique of CSF: perchloric acid (PCA) followed by micro solid phase extraction (μSPE). We could then measure seven tau trypsic peptides by Multiple Reaction Monitoring (MRM) on a triple quadrupole mass spectrometer. Quantification was performed using isotopically labeled (15)N- recombinant tau protein as internal standard and validated using CSF pools with low, medium, or high tau concentrations (HTCs). Repeatability, intermediate precision, linearity, limit of quantification (LOQ), and recovery were calculated for the different peptides. This new MRM assay, which allowed for the first time CSF tau protein quantification without immunocapture, has important potential application to follow tau metabolism in both diagnostic and therapeutic research.

No MeSH data available.


Related in: MedlinePlus

Correlation between MRM and ELISA results.
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Figure 5: Correlation between MRM and ELISA results.

Mentions: Tau concentration determined in the LTC, MTC, and HTC pools using ELISA were 184 pg/mL, 399 pg/mL, and 1096 pg/mL, respectively. For the 7 peptides, concentrations obtained using MRM were highly correlated with those measured by ELISA (r2 above 0.99) (see Figure 5 for the TPSLPTPPTR peptide as an example). However, ELISA concentrations were 17–25 times lower than those measured by MRM.


Antibody-free quantification of seven tau peptides in human CSF using targeted mass spectrometry.

Bros P, Vialaret J, Barthelemy N, Delatour V, Gabelle A, Lehmann S, Hirtz C - Front Neurosci (2015)

Correlation between MRM and ELISA results.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4555028&req=5

Figure 5: Correlation between MRM and ELISA results.
Mentions: Tau concentration determined in the LTC, MTC, and HTC pools using ELISA were 184 pg/mL, 399 pg/mL, and 1096 pg/mL, respectively. For the 7 peptides, concentrations obtained using MRM were highly correlated with those measured by ELISA (r2 above 0.99) (see Figure 5 for the TPSLPTPPTR peptide as an example). However, ELISA concentrations were 17–25 times lower than those measured by MRM.

Bottom Line: Quantification was performed using isotopically labeled (15)N- recombinant tau protein as internal standard and validated using CSF pools with low, medium, or high tau concentrations (HTCs).Repeatability, intermediate precision, linearity, limit of quantification (LOQ), and recovery were calculated for the different peptides.This new MRM assay, which allowed for the first time CSF tau protein quantification without immunocapture, has important potential application to follow tau metabolism in both diagnostic and therapeutic research.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Biochimie et de Protéomique Clinique - Institut de Médecine Régénérative et Biothérapies, Centre Hospitalier Universitaire de Montpellier Montpellier, France ; Laboratoire National de Métrologie et d'Essais (LNE) Paris, France.

ABSTRACT
Tau protein concentration in cerebrospinal fluid (CSF) is currently used as a sensitive and specific biomarker for Alzheimer's disease. Its detection currently relies on ELISA but the perspective of using mass spectrometry (MS) to detect its different proteoforms represents an interesting alternative. This is however an analytical challenge because of its low concentration in the CSF, a biological fluid collected in small volume by lumbar puncture, and with a high structural heterogeneity. To overcome these issues, instead of using immunocapture as previously done, we rather relied on an original two steps pre-fractionation technique of CSF: perchloric acid (PCA) followed by micro solid phase extraction (μSPE). We could then measure seven tau trypsic peptides by Multiple Reaction Monitoring (MRM) on a triple quadrupole mass spectrometer. Quantification was performed using isotopically labeled (15)N- recombinant tau protein as internal standard and validated using CSF pools with low, medium, or high tau concentrations (HTCs). Repeatability, intermediate precision, linearity, limit of quantification (LOQ), and recovery were calculated for the different peptides. This new MRM assay, which allowed for the first time CSF tau protein quantification without immunocapture, has important potential application to follow tau metabolism in both diagnostic and therapeutic research.

No MeSH data available.


Related in: MedlinePlus