= Emerging. More than 5 years before clinical availability.
= Expected to be clinically available in 1 to 4 years.
= Clinically available now.
MSACL 2018 EU : Smith

MSACL 2018 EU Abstract

Topic: Tissue Imaging

MALDI-MSI in the Search for Proteomic Indicators of Response to Therapy in Membranous Nephropathy

Andrew Smith (Presenter)
University of Milano-Bicocca

Presenter Bio: I am currently a post-doctoral researcher at the University of Milano-Bicocca, with my principal line of research focusing on the MALDI-MS imaging of glomerular diseases.

I initially obtained my undergraduate degree from Sheffield Hallam University, reading Forensic and Analytical Science. Following which, my PhD programme was then completed at Milano-Bicocca, under the umbrella of a Marie Curie ITN.

Authors: Andrew Smith (1), Vincenzo L'Imperio (2), Elena Ajello (3), Fabio Pagni (2) and Fulvio Magni (1)
(1) Department of Medicine and Surgery, Clinical Proteomics and Metabolomics Unit, University of Milano-Bicocca, Vedano al Lambro, Italy (2) Department of Medicine and Surgery, Pathology, University of Milano-Bicocca, San Gerardo Hospital, Italy (3) Department of Medicine and Surgery, Nephrology Unit, University of Milano-Bicocca, Monza, Italy

Short Abstract

Here we demonstrate how high spatial resolution MALDI-MSI can assist in the search for proteins able to predict response to treatment in Membranous Nephropathy patients. We present three proteins, macrophage migration inhibitory factor (MIF), Sonic Hedgehog (SHH) and α-smooth muscle actin (α-SMA), whose signal intensity and spatial localisation differed between patients who responded favourably or unvaourably to therapeutic treatment (Ponticelli Regimen). If verified in a larger sample cohort, such findings may have direct clinical relevance and could provide support in the prognostic assessment of MN patients.

Long Abstract

Introduction

Membranous Nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults and the disease course is characterised by the “rule of third”, with one third of patients experiencing complete remission and the remaining experiencing relapses or progression [1]. Moreover, the therapeutic approach is not standardised, leading to further heterogeneity in terms of outcome [2], and a marker that can reliably predict the response of a patient a priori is lacking.

Methods

MALDI-MS imaging of renal biopsies taken from patients who differentially responded to immunosuppressive treatment (Ponticelli regimen) was performed. Initially, FFPE specimens (n=13) were analysed using an ultrafleXtreme™ MALDI-TOF-MS instrument, employing a pixel width and raster setting of 40 µm and 50 μm, respectively [3]. Analysis of additional specimens (n=7) was performed using a rapifleX MALDI Tissuetyper™, employing a pixel width and raster of 10 μm.

Results

Following Receiver Operative Characteristic (ROC) analysis, three signals were determined to have a statistical significance when comparing the two patient groups (m/z 1111, 1198 and 1303). The signal at m/z 1303 displayed the greatest discriminatory power and was observed to be of higher intensity in the glomeruli of the non-responding patients. The corresponding tryptic peptide was putatively identified as macrophage migration inhibitory factor (MIF) and validated using immunohistochemistry, depositing on podocyte and parietal epithelial cells (PEC).

We also generated specific profiles of the mesangial cells and podocytes of the glomeruli whilst employing a 10µm pixel. This high spatial resolution imaging was then used to visualise the spatial localisation of those additional discriminatory signals detected (m/z 1111 and 1198) within the glomerular and tubular structures. These signals were putatively identified as tryptic peptides deriving from sonic hedgehog protein (SHH) and α-smooth muscle actin (SMA), respectively.

Conclusions & Discussion

Despite much effort being made in recent years to understand the pathogenesis of MN, a biomarker able to predict the outcome of these patients following therapeutic treatment is still lacking. Here, we highlight three proteins that could differentiate between these MN patients (MIF, SHH and α-SMA) and thus represents a promising starting point in the search for protein markers to provide complimentary support in the routine prognostic assessment of MN patients.


References & Acknowledgements:

References:

[1] Ponticelli C. J. Nephrol., 20(3), 268–87 (2007)

[2] Ponticelli C., Glassock R.J., J. Am. Soc. Nephrol., 9, 609–16

(2014)

[3] Smith A. et al. Biochim. Biophys. Acta, 1865, 865–874 (2017)

The research leading to these results has received funding from MIUR: FIRB 2007 (RBRN07BMCT_11), FAR 2014–2016 and in part by Fondazione Gigi & Pupa Ferrari Onlus.


Financial Disclosure

DescriptionY/NSource
GrantsyesThe research leading to these results has received funding from MIUR: FIRB 2007 (RBRN07BMCT_11), FAR
Salaryno
Board Memberno
Stockno
Expensesno

IP Royalty: no

Planning to mention or discuss specific products or technology of the company(ies) listed above:

no