(D-130) Development of a Quantitative Spatial Omics Platform

Introduction:: In recent years, the ability to gather omic datasets while preserving the spatial relationship of cell populations and morphological structures present in tissues and organs has gained popularity. The appeal of spatial omics is that it preserves the cellular organization and interactions within tissues, in order to better understand the biology associated with the different disease models and treatments being studied. The utilization of multi-omic datasets (i.e. metabolites, lipids, & protein) in a spatial context is not as well explored, particularly with the ability to attain quantitative measurements of the metabolites and lipids in the whole tissue images.


Materials and Methods:: In the MultiOmics Analysis Group at PTC Therapeutics, we’re developing a quantitative spatial omics platform, consisting of Matrix Assisted Laser Desorption Ionization imaging mass spectrometry (MALDI-IMS, Bruker TimsToF MALDI2, MA, USA) for metabolite and lipid imaging; AmberGen Miralys Photocleavable Mass-Tags (MA, USA) for protein imaging with MALDI-IMS; and immunofluorescence and brightfield imaging with the Zeiss Axio Observer 7 (Jena, Germany) (Fig. 1). To achieve quantitation with the mass spectrometry imaging (IMS), a tissue mimetic model is being developed to create a standard curve, currently experimenting with different embedding material options (e.g. fish gelatin, carboxymethyl cellulose, and optimal cutting temperature).

Flash frozen mouse brains are serially sectioned with the Leica Cryostar NX70 (Wetzlar, Germany). Sections are then spray-coated with CHCA in the HTX M3+ Sprayer (NC, USA) and placed in a desiccator until imaging with the MALDI-ToF. Post-IMS, the same sections are H&E stained for histological imaging to compare and confirm spatial information as needed. Serial sections are stained with selected antibodies for imaging on our Zeiss Axio Observer.
For the quantitative mass spectrometry imaging method development, various mold designs were tested including Ted Pella microarray molds and TPE 3D printed molds with the Prusa Mini+ 3D printer (Prague, Czech Republic). Embedding materials are cast into the mold. After curing, the molds are released and tissue homogenate spiked with isotopically-labeled standards is pipetted into the mold. The mold is then frozen and sectioned for analysis.


Results, Conclusions, and Discussions::
The Q-IMS tissue mimic mold and embedding material was optimized for visual clarity, ease of release from the mold, , and low background signal in the MALDI-ToF analysis. Following this Q-IMS material optimization, different materials were found to provide added benefits depending on the type of imaging desired. The combination of quantitation and spatial multi-omics is new to research labs. The preposed platform shows promise for use in disease model development and drug discovery both in research and academia. This quantitative spatial omics platform will provide comprehensive biochemical stories that can transform our understanding of rare diseases and effective therapies.




Acknowledgements (Optional): :

References (Optional): : [1] Lamont L, Analytical and Biochemistry, 2021, 413:2779–2791, [2] BioRender.com.