Quantitative proteomic analysis of cerebrospinal fluid of women newly diagnosed with multiple sclerosis

Abstract

Purpose

The lack of reliable diagnostic and/or prognostic biomarkers for multiple sclerosis (MS) is the major obstacle to timely and accurate patient diagnosis in MS patients. To identify new proteins associated with MS we performed a detailed proteomic analysis of cerebrospinal fluid (CSF) of patients newly diagnosed with relapsing-remitting MS (RRMS) and healthy controls.

Material

Reflecting significantly higher prevalence of MS in women we included only women patients and controls in the study. To eliminate a potential effect of therapy on the CSF composition, only the therapy-naïve patients were included.

Methods

Pooled CSF samples were processed in a technical duplicate, and labeled with stable-isotope coded TMT tags. To maximize the proteome coverage, peptide fractionation using 2D-LC preceded mass analysis using Orbitrap Fusion Tribrid Mass Spectrometer. Differential concentration of selected identified proteins between patients and controls was verified using specific antibodies.

Results

Of the identified 900 CSF proteins, we found 69 proteins to be differentially abundant between patients and controls. In addition to several proteins identified as differentially abundant in MS patients previously, we observed several linked to MS for the first time, namely eosinophil-derived neurotoxin and Nogo receptor.

Conclusions

Our data confirm differential abundance of several previously proposed protein markers, and provide indirect support for involvement of copper–iron disbalance in MS. Most importantly, we identified two new differentially abundant CSF proteins that seem to be directly connected with myelin loss and axonal damage via TLR2 signaling and Nogo-receptor pathway in women newly diagnosed with RRMS.

Keywords:

• Multiple sclerosis
• proteomics
• cerebrospinal fluid
• markers
• Nogo
• TLR2
• iron
• copper

Acknowledgments

Authors would like to thank Ondrej Vit for his kind assistance with figure preparation.

Ethics approval and consent to participate

The CSF samples were obtained from patients treated at the Center for Demyelinating Diseases, General University Hospital, Prague, Czech Republic. The study was approved by the Ethics Committee of General University Hospital, Prague (approval no. 120/14). All included MS patients and controls signed a written informed consent to participate including consent for publication.

Patient consent for publication

Patient consent for publication was included in the written informed consent signed by all patients enrolled.

Disclosure statement

Authors declare no competing interests. E. K. H. received honoraria/research support from Biogen, Merck Serono, Novartis, Roche, and Teva; E. K. H. is an advisory board member for Actelion, Biogen, Celgene, Merck Serono, Novartis, and Sanofi Genzyme.

Availability of data and materials

The raw proteomic data are available from the corresponding author on reasonable request.

Additional information

Funding

The study was supported by the Ministry of Health of the Czech Republic (NV 15-32961A), by the Ministry of Education, Youth and Sports of the Czech Republic (Progres Q26, Progres Q27, NPU II – LQ1604, SVV 260521, UNCE/MED/016). Authors also acknowledge a support by the projects CZ.1.05/2.1.00/19.0400 and CZ.1.05/1.1.00/02.0109 from the Research and Development for Innovations Operational Program (RDIOP) co-financed by European regional development fund and the state budget of the Czech Republic. E. K. H. received honoraria/research support from Biogen, Merck Serono, Novartis, Roche, and Teva; E. K. H. is an advisory board member for Actelion, Biogen, Celgene, Merck Serono, Novartis, and Sanofi Genzyme.