Mass spectrometry imaging reveals alterations in protein and N-glycan molecular signatures in endometriosis tissues

Endometriosis is a gynecological condition characterized by the uncontrolled growth of endometrial-like tissue outside the uterine cavity. Although highly prevalent, the biological mechanisms of endometriosis are poorly understood, and the disease is often misdiagnosed due to the unavailability of pre-operative diagnostic methods. Thus, better characterization of molecular markers of endometriosis is critical to improve our understanding of the disease and management of patients. Here, we used matrix-assisted laser desorption ionization mass spectrometry (MALDI MS) imaging to investigate protein and N-glycan molecular signatures in eutopic endometrium and endometriosis lesions from tissues prospectively collected from patients. MALDI MS imaging of intact proteins revealed neutrophil defensins detected at higher relative abundances in regions of endometriosis lesions, providing evidence that immune/inflammatory processes may be associated with endometriosis. Various alterations in N-glycan molecular profiles were also observed when comparing endometriosis lesions and eutopic endometrium, including a significantly higher detection of fucosylated N-glycans and increased levels of branching from biantennary to tri- and tetra-antennary structures in endometriosis lesions. These results provide evidence that alterations in N-glycosylation machinery are involved in dysregulation of cellular and signaling processes and may contribute to endometriosis development. A co-localization analysis identified several tryptic peptides detected within regions of endometriosis lesions, suggesting extracellular matrix (ECM) proteins such as collagen may contribute to the development of endometriosis lesions. Overall, by characterizing molecular alterations in proteins and N-glycans, the results of this study provide novel insights into potential mechanisms involved in endometriosis pathogenesis. Graphical Abstract Similar content being viewed by others Data availability All data from this study are deposited and available at Dataverse (https://dataverse.org/).

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Bruker Daltonics is acknowledged for loan of the RapifleX MALDI TOF/TOF mass spectrometer at the Mass Spectrometry Imaging Facility at UT Austin. We thank Dr. Clara Feider for her advice and expertise. Dr. Mary King and Dr. Michael Keating are acknowledged for their assistance with data analysis. We are thankful for Brooke Lasher, Elizabeth Davis, Hitakshi Modi, and Stephanie Nutt for their assistance with sample collection procedures. Funding This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (R01 HD101560-03) and the Cancer Prevention and Research Institute of Texas (CPRIT, Grant No. RP190617). Author information Authors and Affiliations Contributions M.L., M.T.B., and L.S.E. initiated the project and planned experiments. M.L. and E.H.S. performed experiments. M.L. processed and analyzed the data and generated figures. S.L. performed pathological evaluation of tissues. C.S. and M.T.B. obtained the tissue samples. M.L. and L.S.E. wrote the paper with input and edits from other authors. All authors read and approved the final paper. Corresponding author Ethics declarations Ethics approval This study was performed under approved IRB protocols at UT Austin (protocol #2017080087) and Baylor College of Medicine (protocol #H-50480). Conflict of interest The authors declare no competing interests. Additional information Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary Information Below is the link to the electronic supplementary material. Rights and permissions Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law. About this article Cite this article Lin, M., Seeley, E.H., Ledet, S. et al. Mass spectrometry imaging reveals alterations in protein and N-glycan molecular signatures in endometriosis tissues. Anal Bioanal Chem 417, 4133–4145 (2025). https://doi.org/10.1007/s00216-025-05930-z Received: Revised: Accepted: Published: Version of record: Issue date: DOI: https://doi.org/10.1007/s00216-025-05930-z