Project description:The molecular identification of tissue proteoforms by top-down mass spectrometry (TDMS) is significantly limited by throughput and dynamic range. We introduce AutoPiMS, a single-ion MS based multiplexed workflow for top-down tandem MS (MS2) directly from tissue microenvironments in a semi-automated manner. AutoPiMS directly off human ovarian cancer sections allowed for MS2 identification of 73 proteoforms up to 54 kDa at a rate of <1 min per proteoform. AutoPiMS is directly interfaced with multifaceted proteoform imaging MS data modalities for the identification of proteoform signatures in tumor and stromal regions in ovarian cancer biopsies. From a total of ~1000 proteoforms detected by region-of-interest label-free quantitation, we discover 303 differential proteoforms in stroma versus tumor from the same patient. 14 of the top proteoform signatures are corroborated by MSI at 20 micron resolution including the differential localization of methylated forms of CRIP1, indicating the importance of proteoform-enabled spatial biology in ovarian cancer.
Project description:Spatially resolved characterization of proteoforms has great potential to significantly advance our understanding of physiological and disease mechanisms. However, it faces challenges regarding throughput and coverage. Herein, we developed a robust method for high-throughput proteoform imaging (HTPi) by combining matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI MSI) and region-specific top-down proteomic analysis.
Project description:Mass spectrometry (MS)-based spatially resolved top-down proteomics (TDP) of tissues is crucial for understanding the roles played by microenvironmental heterogeneity in the biological functions of organs and for discovering new proteoform biomarkers of diseases. There are few published spatially resolved TDP studies. One of the challenges relates to the limited performance of TDP for the analysis of spatially isolated samples using, for example, laser capture microdissection (LCM) because those samples are usually mass-limited. We present the first pilot study of LCM-capillary zone electrophoresis (CZE)-MS/MS for spatially resolved TDP and used zebrafish brain as the sample. The LCM-CZE-MS/MS platform employed a non-ionic detergent and a freeze-thaw method for efficient proteoform extraction from LCM isolated brain sections followed by CZE-MS/MS without any sample cleanup step, ensuring high sensitivity. Over 400 proteoforms were identified in a CZE-MS/MS analysis of one LCM brain section via consuming the protein content of roughly 250 cells. We observed drastic differences in proteoform profiles between two LCM brain sections isolated from the optic tectum (Teo) and telencephalon (Tel) regions. Proteoforms of three proteins (npy, penkb, and pyya) having neuropeptide hormone activity were exclusively identified in the isolated Tel section. Proteoforms of reticulon, myosin, and troponin were almost exclusively identified in the isolated Teo section, and those proteins play essential roles in visual and motor activities. The proteoform profiles accurately reflected the main biological functions of the Teo and Tel regions of the brain. Additionally, hundreds of post-translationally modified proteoforms were identified.
Project description:DBiTplus utilizes in situ reverse transcription, in-tissue delivery of DNA oligos for spatial barcoding, and RNaseH-mediated selective cDNA retrieval, preserving tissue architecture to enable highly multiplexed protein imaging and spatial transcriptomics on the same slide. Computational pipelines seamlessly integrates these modalities, allowing imaging-guided deconvolution to generate genome-scale, single-cell-resolved spatial transcriptome atlases. DBiTplus was demonstrated across diverse samples including mouse embryos, normal human lymph nodes, and formalin-fixed paraffin-embedded (FFPE) human lymphoma tissues, highlighting its compatibility with challenging clinical specimens. Applying DBiTplus to human lymphoma samples reveals key mechanisms driving lymphomagenesis, progression, and notably, the progression of indolent marginal zone lymphoma (MZL) or the transformation from chronic lymphocytic leukemia (CLL) to diffuse large B-cell lymphoma (DLBCL), including uniquely, the spatially resolved involvement of microRNAs in modulating the transformation dynamics. Thus, DBiTplus is a unified workflow including integrative experimental procedure and computational innovation for spatially resolved single-cell atlasing and exploration of biological pathways cell-by-cell at genome-scale.
Project description:The main goal of this study is to explore the proteomic expression in prophylactic salpingooophorectomy specimens, obtained from highly selected cohort of patients at risk of developing a high-grade serous ovarian carcinoma (HGSOC), because of a hereditary (BRCA 1 or 2 mutation) or a documented familial context. Pathological aspects of fallopian tube specimens, at the origin of most HGSOC in this selected feminine population, are extracted from slides annotated by the pathologist, then submitted to a proteomic analysis. We carried out an in-depth proteomics analysis of these epithelial lesions (p53 signature, serous tubal intraepithelial carcinoma-STIC and serous tubal intraepithelial lesions-STIL) based on spatially resolved proteomic guided by IHC technique.
Project description:Here we present an approach to identify N-linked glycoproteins and deduce their spatial localization using a combination of MALDI N-glycan MSI and spatially-resolved glycoproteomics. We subjected glioma biopsies to on-tissue PNGaseF digestion and MALDI-MSI and found that the glycan HexNAc4-Hex5-NeuAc2 was predominantly expressed in necrotic regions of high-grade canine gliomas. To determine the underlying sialo-glycoprotein, various regions in adjacent tissue sections were subjected to microdigestion and manual glycoproteomic analysis. Results identified haptoglobin as the protein associated with HexNAc4-Hex5-NeuAc2, making our study the first report that directly links glycan imaging with intact glycopeptide identification. In total, our spatially-resolved glycoproteomics technique identified over 400 N-, O-, and S- glycopeptides from over 30 proteins, demonstrating the diverse array of glycosylation present on the tissue slides and the sensitivity of our technique. Ultimately, this proof-of-principle work demonstrates that spatially-resolved glycoproteomics greatly complement MALDI-MSI in understanding dysregulated glycosylation.
Project description:Here we present an approach to identify N-linked glycoproteins and deduce their spatial localization using a combination of MALDI N-glycan MSI and spatially-resolved glycoproteomics. We subjected glioma biopsies to on-tissue PNGaseF digestion and MALDI-MSI and found that the glycan HexNAc4-Hex5-NeuAc2 was predominantly expressed in necrotic regions of high-grade canine gliomas. To determine the underlying sialo-glycoprotein, various regions in adjacent tissue sections were subjected to microdigestion and manual glycoproteomic analysis. Results identified haptoglobin as the protein associated with HexNAc4-Hex5-NeuAc2, making our study the first report that directly links glycan imaging with intact glycopeptide identification. In total, our spatially-resolved glycoproteomics technique identified over 400 N-, O-, and S- glycopeptides from over 30 proteins, demonstrating the diverse array of glycosylation present on the tissue slides and the sensitivity of our technique. Ultimately, this proof-of-principle work demonstrates that spatially-resolved glycoproteomics greatly complement MALDI-MSI in understanding dysregulated glycosylation.
Project description:High-grade serous ovarian cancer (HGSOC) is often detected at an advanced stage, where curative treatment options are limited. Recent advances in ultrasensitive mass spectrometry-based spatial proteomics have provided a unique opportunity to uncover molecular drivers of early tumorigenesis and novel therapeutic targets. Here, we present a comprehensive proteomic analysis of serous tubal intraepithelial carcinoma (STIC), the HGSOC precursor lesion, and concurrent invasive carcinoma, covering more than 10,000 proteins from ultra-low input archival tissue. STIC and HGSOC showed highly similar proteomes, clustering into two subtypes with distinct tumor immune microenvironments and common remodelling of the extracellular matrix. We discovered cell-of-origin signatures from secretory fallopian tube epithelial cells in STICs and identified early dysregulated pathways of therapeutic relevance. Targeting cholesterol biosynthesis by inhibiting the terminal steps via DHCR7 showed therapeutic effects in ovarian cancer cell lines and synergized with standard-of-care carboplatin treatment. This study demonstrates the power of spatially resolved quantitative proteomics in understanding early carcinogenesis and provides a rich resource for biomarker and drug target research.
Project description:Method development for high-resolution spatially-resolved proteome mapping of tissue heterogeneity. Laser microdissection was coupled with nanodroplet sample preparation and ultrasensitive LC-MS.