bioRxiv Science⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/605568

Imaging toxin-induced neuroinflammation in mice using hyperpolarized 13C magnetic resonance spectroscopy

Le Page, L. M.·Guglielmetti, C.·Najac, C. F.·Tiret, B.·Chaumeil, M. M.
View original source ↗Export metadata ↓

Abstract

Lipopolysaccharide (LPS) is a commonly used agent for induction of neuroinflammation in preclinical studies. Upon injection, LPS causes activation of microglia and astrocytes, whose metabolism alters to favor glycolysis. Assessing in vivo neuroinflammation and its modulation following therapy remains challenging, and new non-invasive methods allowing for longitudinal monitoring would be greatly valuable. Hyperpolarized (HP) 13C magnetic resonance spectroscopy (MRS) is a promising technique for assessing in vivo metabolism. In addition to applications in oncology, the most commonly used probe of [1-13C] pyruvate has shown potential in assessing neuroinflammation-linked metabolism in mouse models of multiple sclerosis and traumatic brain injury. Here, we wished to investigate LPS-induced neuroinflammatory changes using HP [1-13C] pyruvate and HP 13C urea.\n\n2D chemical shift imaging following simultaneous intravenous injection of HP [1-13C] pyruvate and HP 13C urea was performed at baseline (day 0), day 3 and day 7 post intracranial injection of LPS (n=6) or saline (n=5). Immunofluorescence (IF) analyses were performed for Iba1 (resting and activated microglia/macrophages), GFAP (resting and reactive astrocytes) and CD68 (activated microglia/macrophages).\n\nA significant increase in HP [1-13C] lactate production was observed in the injected (ipsilateral) side at 3 and 7 days of the LPS-treated mouse brain, but not in either the contralateral side or saline-injected animals. HP 13C lactate/pyruvate ratio, without and with normalization to urea, was also significantly increased in the ipsilateral LPS-injected brain at 7 days compared to baseline. IF analyses showed a significant increase in CD68 and GFAP at 3 days, followed by increased numbers of Iba1 and GFAP positive cells at 7 days post-LPS injection.\n\nIn conclusion, we can detect LPS-induced changes in the mouse brain using HP 13C MRS, in alignment with increased numbers of microglia/macrophages and astrocytes. This study demonstrates that HP 13C spectroscopy holds much potential for providing non-invasive information on neuroinflammation.

Explore related subjects

immunologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Le Page, L. M., Guglielmetti, C., Najac, C. F., Tiret, B., Chaumeil, M. M.. 2019-04-11. Imaging toxin-induced neuroinflammation in mice using hyperpolarized 13C magnetic resonance spectroscopy. https://doi.org/10.1101/605568

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Proteome-wide discovery of novel diagnostic antigens for coccidioidomycosis

Coccidioidomycosis, commonly called Valley Fever (VF), caused by Coccidioides spp., is an understudied fungal disease that accounts for a substantial fraction of pneumonias in endemic areas. Diagnosis remains challenging because the mainstay of diagnosis is serology, and current assays have modest sensitivity in early infection. Discovery of new antigens could improve serologic detection early in disease. Here, we use PepSeq, a DNA-programmable serology platform, to represent the complete proteome of Coccidioides within a library of 244,000 DNA-barcoded peptides. By profiling antibody reactivity at the protein and epitope levels in VF patients, naturally infected pigtail macaques, and healthy controls, we identify numerous previously-unrecognized antigens and epitopes, including some shared between humans and macaque responses. When translated into a pooled peptide ELISA, we show that a subset of identified antigens can discriminate VF cases from controls in an independent cohort with high accuracy (AUC = 0.91). These findings establish high-dimensional peptide serology as a scalable approach for fungal antigen discovery and identify new targets for improved VF diagnosis.

immunology↗
bioRxiv2026

Establishing an ex vivo platform for molecular profiling of skin structural cells using frozen human skin biopsies

Skin structural cells, including keratinocytes, melanocytes, endothelial cells, and fibroblasts, play critical roles in the development of chronic inflammatory skin disease. Inflammatory stimuli induce transcriptional reprogramming and epigenetic changes in skin structural cells, which contribute to disease pathogenesis. Although two-dimensional (2D) and three-dimensional (3D) skin culture models have been widely used to investigate inflammatory responses in skin structural cells, ex vivo systems that maintain skin structure and cellular composition remain limited. To address this gap, we explored using frozen skin biopsies as an experimental platform to study the responses of skin structural cells to inflammatory stimuli. Using a simple air-liquid interface culture method on permeable Transwell inserts, we showed that viable skin structural cells that retain cell-type-specific transcriptional profiles can be recovered from frozen skin biopsies after prolonged in vitro culture. Stimulation with IFN-{gamma} induced robust transcriptional and chromatin accessibility changes that were largely resolved after stimulus removal, with transcriptional responses to secondary stimulation comparable to the primary stimulation. Treatment of cultured skin biopsies with histone-modifying enzyme inhibitors effectively altered global histone modification levels, but did not substantially affect the transcriptional resolution of IFN-{gamma}-induced responses. Collectively, these findings establish cryopreserved human skin biopsies as a scalable ex vivo platform that enables mechanistic studies of inflammatory responses of multiple populations of skin structural cells.

immunology↗
bioRxiv2026

γδ T cell-derived IL-17A aggravates experimental epidermolysis bullosa acquisita in response to IL-1β

Epidermolysis bullosa acquisita (EBA) is a mucocutaneous autoimmune blistering disorder mediated by autoantibodies against type VII collagen and subsequent splitting of the dermal-epidermal junction. Interleukin (IL)-17A promotes the production of chemokines and cytokines involved in neutrophil recruitment and activation, suggesting that IL-17A may contribute to EBA pathogenesis. We aimed to clarify the role of IL-17A in experimental EBA. Using an antibody transfer-induced EBA mouse model, we demonstrate that IL-17A promotes disease development, as pharmacological blockade of IL-17A with a neutralizing antibody ameliorated skin lesions. Gamma-delta ({gamma}{delta}) T cells were identified as the predominant cellular source of IL-17A, supported by the attenuated disease phenotype observed in {gamma}{delta}TCR-deficient mice. In addition, CD4+ T cells and neutrophils contributed to IL-17A production in experimental EBA. Mechanistically, IL-1-beta, rather than IL-23, was identified as a critical mediator of IL-17A production by {gamma}{delta} T cells in vitro, consistent with our in vivo findings. Whereas EBA severity was not reduced in IL-23p19-deficient mice, disease was markedly attenuated in IL-1R-deficient animals. Together, our study provides the first evidence that {gamma}{delta} T cell-derived IL-17A plays a pivotal role in experimental EBA and identifies a previously unrecognized IL-1{beta}/{gamma}{delta} T cell/IL-17A axis that expands current understanding of EBA immunopathogenesis.

immunology↗