Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Imaging of Key Proteins in Corneal Samples from Lattice Dystrophy Patients with TGFBI-H626R and TGFBI-R124C Mutations

Anandalakshmi Venkatraman, Guillaume Hochart, Jonathan Stauber, Shigeto Shimmura, Lakshminaryanan Rajamani, Konstantin Pervushin,
and Jodhbir S. Mehta.

Dr. A. Venkatraman, Dr. L. Rajamani, Dr. J. S. Mehta
11 Third Hospital Avenue, 168751, Singapore

Dr. A. Venkatraman, Dr. K. Pervushin
School of Biological Sciences
Nanyang Technological University
637551, Singapore

G. Hochart, Dr. D. Bonnel, Dr. J. Stauber
Parc Eurasanté
152 rue du Docteur Yersin 59120 Loos

Dr. S. Shimmura
Department of Ophthalmology
Keio University
35 Shinanomachi, 160-8582, Shinjuku Tokyo, Japan

Dr. L. Rajamani, Dr. J. S. Mehta
Ophthalmology and Visual Sciences Academic Clinical Program
Duke-NUS Graduate Medical School
169857, Singapore

Dr. J. S. Mehta
Singapore National Eye Centre
11 Third Hospital Avenue, 168751, Singapore

Scope: The purpose of this study is to identify and visualize the spatial
distribution of proteins present in amyloid corneal deposits of TGFBI-CD patients using Mass Spectrometry Imaging (MSI) and compare it with healthy control cornea. Corneal Dystrophies (CD) constitute a group of genetically inherited protein aggregation disorders that affects different layers of the cornea. With accumulated protein deposition, the cornea becomes opaque with decreased visual acuity. CD affecting the stroma and Bowman’s membrane, is associated with mutations in transforming growth factor β-induced (TGFBI) gene.

Methods: MALDI-Mass Spectrometry Imaging (MSI) is performed on 2
patient corneas and is compared with 1 healthy control cornea using a
7T-MALDI-FTICR. Molecular images obtained are overlaid with congo-red stained sections to visualize the proteins associated with the corneal amyloid aggregates.

Results: MALDI-MSI provides a relative abundance and two dimensional spatial protein signature of key proteins (TGFBIp, Apolipoprotein A-I, Apolipoprotein A-IV, Apolipoprotein E, Kaliocin-1, Pyruvate Kinase and Ras related protein Rab-10) in the patient deposits compared to the control. This is the first report of the anatomical localization of key proteins on corneal tissue section from CD patients. This may provide insight in understanding the mechanism of amyloid fibril formation in TGFBI-corneal dystrophy.

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