Characterizing the Natural History of Acute Radiation Syndrome of the Gastrointestinal Tract: Combining High Mass and Spatial Resolution Using MALDI-FTICR-MSI

Abstract

The acute radiation syndrome of the gastrointestinal tract has been histologically characterized but the molecular and functional mechanisms that lead to these cellular alterations remain enigmatic. Mass spectrometry imaging is the only technique that enables the simultaneous detection and cellular or regional localization of hundreds of biomolecules in a single experiment. This current study utilized matrix-assisted laser desorption/ionization mass spectrometry imaging for the molecular characterization of the first natural history study of GI-ARS in the non-human primate. Jejunum samples were collected at days 4, 8, 11, 15 and 21 following 12 Gy partial body irradiation with 2.5% bone marrow sparing. Mass spectrometry imaging investigations identified alterations in lipid species that further understanding of the functional alterations that occur over time in the different cellular regions of the jejunum following exposure to high doses of irradiation. Alterations in phosphatidylinositol species informed on dysfunctional epithelial cell differentiation and maturation. Differences in glycosphingolipids of the villi epithelium that would influence the absorptive capacity and functional structure of the brush border membrane were detected. Dichotomous alterations in cardiolipins indicated altered structural and functional integrity of mitochondria. Phosphatidylglycerol species, known regulators of toll-like receptors, were detected and localized to regions in the lamina propria that contained distinct immune cell populations. These results provide molecular insight that can inform on injury mechanism in a non-human primate model of the acute radiation syndrome of the gastrointestinal tract. Findings may contribute to the identification of therapeutic targets and the development of new medical countermeasures.

Proteomic Evaluation of the Natural History of the Acute Radiation Syndrome of the Gastrointestinal Tract in a Non-human Primate Model of Partial-body Irradiation with Minimal Bone Marrow Sparing Includes Dysregulation of the Retinoid Pathway

“…Sampling occurred from NHP at timed euthanasia as planned at day 4, 8, 15, and 21 after radiation as well as from NHP that were euthanized for cause according to pre-defined euthanasia criteria. Previous publications have described this PBI model and the analysis of resulting tissue injury (MacVittie et al 2012a;Jones et al 2015a;Shea-Donohue et al 2016;Cohen et al 2017;Prado et al 2017;Carter et al 2019;Cohen et al 2019;MacVittie et al 2019a;MacVittie et al 2019b;Parker et al 2019a;Parker et al 2019b;Parker et al 2019c).…”

“…Such exposures are likely to include bone marrow sparing and to permit the concurrent analysis of coincident short-and long-term damage to organ systems in a time and dose dependent manner (MacVittie et al 2012a). Previous publications by our team have described this PBI model, the analysis of resulting tissue injury, as well as its use for medical countermeasure development (MacVittie et al 2012a;Jones et al 2015a;MacVittie et al 2015;Shea-Donohue et al 2016;Cohen et al 2017;Prado et al 2017;Carter et al 2019;Cohen et al 2019;Farese et al 2019;MacVittie et al 2019a;MacVittie et al 2019b;Parker et al 2019a;Parker et al 2019b;Parker et al 2019c). Here we sought to further characterize the natural history of radiation-induced injury in NHP via determination of differential protein expression in jejunum.…”

“…More studies have focused on the complementary metabolome; metabolomic interrogation of intestine after radiation exposure has been reported for mouse, rat and NHP (Cheema et al 2014;Jang et al 2016;Cheema et al 2019a;Cheema et al 2019b;Jones et al 2019) and Kumar, Wang, et al in this issue. Additionally, a mass spectrometry imaging interrogation of the lipid alterations across the natural history of the PBI/BM2.5 model has been reported (Carter et al 2019). To help inform on the natural history of the GI-ARS in the NHP PBI/BM2.5 model, we quantitatively profiled the jejunum proteome of NHPs over a time period of three weeks.…”

Clostridioides difficile infection induces a rapid influx of bile acids into the gut during colonization of the host

“…IMS has also been applied to the intestines in a variety of studies outside the context of host-pathogen interactions ( Nguyen et al, 2019 ). Most imaging experiments have probed discrete regions of the intestine for analysis due to the difficulty in preparing large sections of intestine for sectioning ( Carter et al, 2019 ). Our study, however, underscores the importance of including luminal content in MALDI IMS analysis for a more representative analysis of the gut, as seen by the bile acid localization patterns previously not shown with traditional sample preparation approaches ( Figure S1 ) ( Genangeli et al, 2019 ).…”

Multimodal Imaging Mass Spectrometry of Murine Gastrointestinal Tract with Retained Luminal Content Shows Molecular Localization Patterns

“…4,5 Matrix assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) has been employed to provide spatially-associated chemical information for molecular species in mammalian GI tissue. [6][7][8] These studies do not encompass the entirety of the GI tract, as either an incomplete portion of the tissue is probed or the luminal content is removed. Sample preparation of this organ must be improved to leverage MALDI IMS for analysis of all regions of the GI tract.…”