Biology subjects

Sommella, E. M.

Publications and source records attributed to Sommella, E. M..

3 recordsLinked to original sources

bioRxiv2026

Ion Mobility-Guided Tandem Mass Spectrometry Imaging Resolves Bis(monoacylglycero)phosphate and Phosphatidylglycerol Isomers in Tissue

Molecular specificity remains a major challenge in mass spectrometry imaging (MSI), particularly when low-abundance species coexist with structurally related isomers that cannot be distinguished by accurate mass and exhibit similar fragmentation behavior. Bis(monoacylglycero)phosphates (BMPs), lysosomal lipids increasingly implicated in lipid homeostasis and disease, represent a particularly demanding example because they are structural isomers of phosphatidylglycerols (PGs) and display highly similar negative-ion fragmentation. Here, we developed an ion mobility-guided targeted MALDI-MS/MS imaging workflow for direct on-tissue discrimination of endogenous BMP/PG isomeric pairs. Orthogonal HILIC-DDA-PASEF analysis provided accurate-mass, retention-time, fragmentation, and ion-mobility information used to define mobility-constrained precursor coordinates for scheduled MALDI-iPRM-PASEF acquisition. Ion-mobility measurements showed high agreement across ESI-TIMS, MALDI-TIMS, and tissue-based MALDI-TIMS-MSI, while optimization of laser sampling minimized ion-load-dependent mobility shifts. Narrow mobility windows reduced reciprocal PG/BMP cross-talk to below 4% while preserving selective detection under strongly unbalanced abundance conditions. The workflow enabled distinct precursor- and product-ion imaging of endogenous PG 34:1 and BMP 34:1 in sagittal mouse brain, supporting their acyl-chain-level assignment as PG 16:0_18:1 and BMP 16:0_18:1. Application to a CLN3-knockout mouse model revealed BMP-specific reductions across brain, kidney, and lung that were not mirrored by the corresponding PG isomers, providing an orthogonal biological validation of the analytical discrimination. Mobility-constrained targeted MS/MS additionally resolved type-II isotopic interference that remained ambiguous at the MS1 level. Overall, this work provides a strategy for reciprocal spatial discrimination and structural confirmation of endogenous BMP and PG isomers directly in tissue and highlights the value of combining ion mobility with targeted product-ion imaging to increase molecular specificity in spatial lipidomics.

biochemistry↗

bioRxiv2025

A missense mutation in Muc2 promotes gut microbiome- and metabolome-dependent colitis-associated tumorigenesis.

Colitis-associated cancer (CAC) arises from a complex interplay between host and environmental factors, including the gut microbiome. Since ulcerative colitis (UC), a significant risk factor for CAC, is rising in prevalence worldwide, an integrative approach is essential to identify potential triggers linking inflammation to cancer. In the present study, we investigated the role of the gut microbiome using Winnie mice, a UC-like model with a relevant missense mutation in the Muc2 gene. Upon transfer from a conventional (CONV) to a specific-pathogen-free (SPF) facility, Winnie mice exhibited a more severe colitis phenotype, and notably, spontaneous CAC as early as four weeks of age, which progressively worsened over time. In contrast, CONV Winnie developed only mild colitis but with no overt signs of tumorigenesis. Notably, when rederived into germ-free (GF) conditions, SPF Winnie mice were protected from colitis or colon tumor development, indicating an essential role for the gut microbiome in the initiation and progression of CAC in these mice. Using shotgun metagenomics, metabolomics, and lipidomics, we identified a distinct pro-inflammatory microbial and metabolic signature that potentially drives the transition from colitis to CAC. Fecal microbiota transplantation (FMT), using either SPF Winnie or WT (Bl/6) donors into GF Winnie recipients, demonstrated that while colitis developed regardless of donor, only FMT from SPF Winnie donors resulted in CAC, revealing a microbiota-driven, host-specific susceptibility to tumorigenesis in Winnie mice. Our studies present a novel and relevant model of CAC, providing further evidence that the microbiome plays a key role in the pathogenesis of CAC, thereby challenging the concept of colon cancer as a strictly non-transmissible disease. Lay summaryThis study reveals a distinct metagenomic, metabolomic, and lipidomic profile associated with tumorigenesis in a murine model of ulcerative colitis, highlighting the risks of specific intestinal dysbiosis in genetically predisposed subjects. What you need to knowO_ST_ABSBackground and contextC_ST_ABSColitis-associated colorectal cancer arises from complex host-environment interactions, including gut microbiome influences, driving chronic inflammation, with the intestinal lumen environment remaining a largely unexplored potential risk factor in cancer development. New findingsWinnie mice in specific pathogen-free conditions developed severe colitis, and a novel juvenile colon dysplasia and cancer, with gut microbiome changes driving colitis-associated cancer initiation and progression. LimitationsWe identified a pro-inflammatory microbial/metabolic signature promoting colitis-to-CAC transition in Winnie mice, with FMT confirming microbiota-driven tumor susceptibility. However, further research is needed to pinpoint the key bacteria-metabolite-lipid combination driving CAC. Clinical research relevanceThis newly characterized microbiota-metabolome-based model of CAC, challenges the dogma of cancer as a non-transmittable disease, providing a foundation for developing microbiota-based strategies for CAC prevention and treatment. Basic research relevanceUnlike genetic or chemically induced models, the Winnie mouse model uniquely serves as a dual model for spontaneous colitis and juvenile CAC, offering a fast, 100% penetrant phenotype that enhances reliability, accelerates research, and provides valuable insights into IBD and CAC.

cancer biology↗

bioRxiv2024

Development of a high-throughput 3D culture microfluidic platform for multi-parameter phenotypic and omics profiling of patient-derived organoids

Patient-derived organoids (PDOs) are poised to become central tools both in clinical practice, to preemptively identify patient optimal treatments, and in drug discovery, overcoming the limitations of cancer cell lines. However, the use of PDOs in these settings has been hampered by several bottlenecks, including sample requirements, assay time, and handling in the context of high-throughput assays. We developed a Microfluidic Platform for Organoids culture (MPO) that miniaturises and simplifies PDOs cultures in a 384-plate format. Both retrospective and prospective clinical studies demonstrate MPO predictive value and the straightforward implementation in the clinical setting. MPO allows subcellular phenotypic screenings, as imaging-based applications like Cell Painting, target engagement analyses, alongside the comprehensive definition of PDOs genomic, transcriptomic, proteomic, lipidomic, and metabolomic landscapes. Harnessing the pleiotropic capabilities of MPO, we uncovered the role of EZH2 inhibitors to prevent the long-term emergence of resistance to RAS inhibitors in metastatic colon cancer. In all, we demonstrate the potential of MPO to impact clinical practice, alongside exploration of the mechanisms underlying compound response and resistance.

cancer biology↗