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3rd International Top-Down Proteomics Symposium

Aug 25 – 29, 2025
Lecture Hall D
Europe/Berlin timezone

Probing Human Oocyte Heterogeneity by Single Cell Proteoform Imaging Mass Spectrometry

Not scheduled
20m
VMP 6 / Philturm (Lecture Hall D)

VMP 6 / Philturm

Lecture Hall D

Von-Melle-Park 6 20146 Hamburg
Oral Presentation Poster Session 2

Speaker

Nickolas Fisher (Department of Chemistry and Molecular Biosciences, Northwestern University, Evanston, IL, USA.)

Description

Ovarian tissue cryopreservation (OTC) is utilized by clinics to preserve oocytes and immature eggs for pediatric patients who are at increased risk of becoming infertile due to a diagnosis or treatment. Late-stage oocytes, that are not yet mature, are often released during OTC. We are interested in identifying proteoforms that may improve in vitro maturation of oocytes into eggs for these patients as an additional fertility preservation strategy. We are utilizing single cell proteoform imaging mass spectrometry (scPiMS), which is a nanoDESI direct sampling approach coupled to individual ion mass spectrometry (I2MS) detection, to profile human oocytes to identify and assess the intact proteoform population between single oocytes. We have used this scPiMS approach to analyze 24 denuded oocytes from 6 different participants/donors aged 1.71 years old to 33. We have also utilized the high spatial resolution afforded by the scPiMS probe (~100 µM) to selectively sample oocytes and cumulus granulosa cells within 4 cumulus oocyte complexes (COCs) from two participants to identify proteoforms that are cell-type specific. We have identified ~78 proteoforms on average across the 28 oocytes sampled, with an average identification rate of THRASH proteoform features of ~55%. We have identified several proteoforms that are highly specific to oocytes rather than cumulus granulosa cells, including oocyte expressing protein homolog (OOEP), KH-domain containing protein 3 (KHDC3), and ferritin light chain. We utilized this data to further understand the proteomic heterogeneity of single oocytes between patients and between multiple oocytes from the same donor. Finally, we demonstrate the utility of scPiMS for analyzing patient specific proteoform landscapes by identifying OOEP and KHDC3 proteoforms with SNPs and variable modifications across the cohort. We ultimately aim to expand our analysis to quantify the abundance of these proteoforms and understand how proteoform landscapes change in the context of age.

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Authors

Chelsea Lock (Department of Chemistry and Molecular Biosciences, Northwestern University, Evanston, IL, USA.) Dr Diane C. Saunders (Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago and Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA) Dr Elizabeth L. Tsui (Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago and Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA) Hannah B. McDowell (Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago and Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA) Dr Indira Pla Parada (Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA) Dr Jared O. Kafader (Department of Chemistry and Molecular Biosciences, Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA) Prof. Monica M. Laronda (Stanley Manne Children’s Research Institute, Ann & Robert H. Lurie Children’s Hospital of Chicago, Department of Pediatrics, Feinberg School of Medicine, Department of Obstetrics and Gynecology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA) Prof. Neil L. Kelleher (1Department of Chemistry and Molecular Biosciences, 2Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA) Nickolas Fisher (Department of Chemistry and Molecular Biosciences, Northwestern University, Evanston, IL, USA.) Dr Tian Xu (Proteomics Center of Excellence, Northwestern University, Evanston, IL, USA) Dr Vijaya Kanchustabahm (Proteomics Center of Excellence, Northwestern University)

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