Reprogramming of IELs at the intestinal epithelial barrier during virus infection

Projektinformationen

Virus RePro IEL

ID Finanzhilfevereinbarung: 101027263

DOI

10.3030/101027263

Projekt abgeschlossen

EK-Unterschriftsdatum 8 April 2021

Startdatum 1 Januar 2022

Enddatum 28 Februar 2024

Finanziert unter

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Gesamtkosten

€ 147 463,68

EU-Beitrag

€ 147 463,68

Koordiniert durch

SVEUCILISTE U RIJECI, MEDICINSKI FAKULTET
Croatia

Periodic Reporting for period 1 - Virus RePro IEL (Reprogramming of IELs at the intestinal epithelial barrier during virus infection)

Berichtszeitraum: 2022-01-01 bis 2023-12-31

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

This MSCA offers a chance to explore how MCMV shapes CD8 T cells at the intestinal epithelial barrier and the processes involved in this modulation within mucosal defenses. The relationship between T cells and viruses presents a major challenge in contemporary medicine. Deepening our knowledge of viral interactions with T cells at the intestinal barrier is essential for grasping the pathogenesis of viral infections at mucosal barriers.

The data we gathered could lead to new diagnostic methods and therapeutic targets for intestinal mucosal issues, which are of considerable health importance.

We sought to explore the behavior of intraepithelial lymphocytes (IELs) in infected and non-infected mice and their response to different intestinal challenges, such as DSS-induced colitis, antibiotic treatment, and a high-fat diet. Our primary goal was to identify the potential mechanisms by which the virus influences IELs at the intestinal epithelial barrier in infected mice and to compare this with the impact of virus infection on circulating CD8 T cells in the spleen.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

We infected mice with the mouse cytomegalovirus (MCMV) that colonizes most of the tissues and organs including the small intestine. TCRαβ CD8αβ IELs exhibited the highest proliferation, T-bet expression, and a proportion of them are virus-specific CD8 T cells. These TCRαβ CD8αβ IELs mirror TCRαβ CD8αβ cells in the spleen during MCMV infection, raising questions about their origin.

We also examined surface receptors on IELs linked to MCMV infection and activation. KLRG1 was highly expressed across IEL subsets. 2B4 (CD244) and NKG2D were highly expressed on TCRαβ CD8αα IELs. Surprisingly, by surface staining I found that all IEL subsets expressed chemokine CCL5, unlike TCRαβ CD8αβ T cells in the spleen, indicating small intestine-specific regulation. The expression of this activation receptors and expression of chemokine CCL5 on the surface of all subset of IELs suggests that MCMV could have a role in the regulation of all three subtypes of IELs. Interestingly, lipid droplet formation was increased in spleen CD8 T cells but decreased in IELs during MCMV infection. These findings require further studies on lipid droplet production by other immune cell types, particularly with regard to the role of the unique environment of the small intestine on IELs.

Mitochondrial staining remained unaffected during MCMV infection, possibly due to distinct metabolic pathways triggered by this virus compared to other pathogens. High-fat diet experiments showed IEL activation without affecting virus-infected and non-infected mice, requiring further testing.

In conclusion, comparing impact of systemic infection on CD8 T cells in the spleen and small intestine during MCMV infection provided valuable insights for future research.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

Further experiments are required to determine whether TCRαβ CD8αβ IELs are tissue-resident in the small intestine or infiltrate from the spleen or other secondary lymphoid organs as TCRαβ CD8αβ cells. We intend to use RAG2 knockout mice adoptively transferred with congenic TCRαβ CD8αβ from the spleen. This approach will help us to confirm or rule out the infiltration of TCRαβ CD8αβ from the spleen into the small intestine during MCMV infection.

Differences in T-bet expression, proliferation, and M45 levels between induced TCRαβ CD8αβ IELs and natural TCRαβ CD8αα and TCRγδ CD8αα IELs suggest their roles in MCMV infection. Induced TCRαβ CD8αβ IELs act like classical virus-specific TCRαβ CD8αβ T cells, while natural IELs show low proliferation, T-bet, and high 2B4 (CD244) and KLRG1 expression, hinting at an innate immune response to MCMV. However, further investigation, such as transcriptome sequencing and differential expression analysis, is needed to confirm these distinctions and comprehensively understand the responses of all IEL subsets to MCMV infection. These results will be crucial for understanding the effects of viral infection on CD8 T cells at the intestinal epithelial barrier and important for developing mucosal-specific treatments in virus and stress-induced epithelial environments.

Investigating virus infection and stress disruption at the intestinal epithelial barrier site to pro