| 1. |
- Alfredsson, Johannes, et al.
(author)
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Isobaric labeling-based quantitative proteomics of FACS-purified immune cells and epithelial cells from the intestine of Crohn's disease patients reveals proteome changes of potential importance in disease pathogenesis.
- 2023
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In: Proteomics. - : Wiley. - 1615-9861 .- 1615-9853. ; 23:5
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Journal article (peer-reviewed)abstract
- Crohn's disease (CD) is a chronic condition characterized by recurrent flares of inflammation in the gastrointestinal tract. Disease etiology is poorly understood and is characterized by dysregulated immune activation that progressively destroys intestinal tissue. Key cellular compartments in disease pathogenesis are the intestinal epithelial layer and its underlying lamina propria. While the epithelium contains predominantly epithelial cells, the lamina propria is enriched in immune cells. Deciphering proteome changes in different cell populations is important to understand CD pathogenesis. Here, using isobaric labeling-based quantitative proteomics, we perform an exploratory study to analyze in-depth proteome changes in epithelial cells, immune cells and stromal cells in CD patients compared to controls using cells purified by FACS. Our study revealed increased proteins associated with neutrophil degranulation and mitochondrial metabolism in immune cells of CD intestinal mucosa. We also found upregulation of proteins involved in glycosylation and secretory pathways in epithelial cells of CD patients, while proteins involved in mitochondrial metabolism were reduced. The distinct alterations in protein levels in immune- versus epithelial cells underscores the utility of proteome analysis of defined cell types. Moreover, our workflow allowing concomitant assessment of cell-type specific changes on an individual basis enables deeper insight into disease pathogenesis.
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| 2. |
- Gorreja, Frida, et al.
(author)
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MEFV and NLRP3 Inflammasome Expression Is Attributed to Immature Macrophages and Correlates with Serum Inflammatory Proteins in Crohn ' s Disease Patients
- 2022
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In: Inflammation. - : Springer Science and Business Media LLC. - 0360-3997 .- 1573-2576. ; 45, s. 1631-1650
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Journal article (peer-reviewed)abstract
- Inflammasomes are intracellular protein complexes whose activation results in proinflammatory cytokines. Inflammasomes are implicated in Crohn ' s disease (CD) pathogenesis, yet the contribution of inflammasomes in intestinal epithelial cells (IECs) versus lamina propria (LP) macrophages is poorly understood. Whether inflammasome expression in intestinal tissue reflects the serum inflammatory protein profile of patients is also not known. We aimed to determine the intestinal cell types where inflammasome expression is increased in CD and if they correlate with the serum protein profile. RT-PCR and NanoString nCounter technology were used to characterize inflammasome gene expression in CD patients and controls. The mucosa, LP and IEC cell fractions and FACS-sorted cells were analyzed. Proximity extension assay with a 92-protein panel was used to determine the serum inflammatory protein profile. Compositional analysis was used to correlate ileum inflammasome gene expression with intestinal mononuclear phagocyte populations. We show that NLRP3 and MEFV inflammasome sensors and downstream effector expression including IL-1 beta are increased in inflamed mucosa of IBD patients and correlate with disease activity. Inflammasome gene expression increased with the abundance of immature intestinal macrophages, and increased IL-1 beta released by CD LP cells correlated with immature macrophage frequency. Inflammasome gene expression was also increased in circulating monocytes, the precursors of immature intestinal macrophages. Finally, the serum inflammatory profile of CD patients correlates with ileal expression of genes related to NLRP3 and MEFV inflammasomes. Overall, we show that MEFV and NLRP3 inflammasome expression in CD intestine is attributed to the accumulation of immature macrophages and correlates with serum inflammatory proteins.
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| 3. |
- Alfredsson, Johannes, et al.
(author)
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Mechanism of fibrosis and stricture formation in Crohn's disease
- 2020
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In: Scandinavian Journal of Immunology. - : Wiley. - 0300-9475 .- 1365-3083. ; 92:6
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Research review (peer-reviewed)abstract
- Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract that leads to substantial suffering for millions of patients. In some patients, the chronic inflammation leads to remodelling of the extracellular matrix and fibrosis. Fibrosis, in combination with expansion of smooth muscle layers, leaves the bowel segment narrowed and stiff resulting in strictures, which often require urgent medical intervention. Although stricture development is associated with inflammation in the affected segment, anti-inflammatory therapies fall far short of treating strictures. At best, current therapies might allow some patients to avoid surgery in a shorter perspective and no anti-fibrotic therapy is yet available. This likely relates to our poor understanding of the mechanism underlying stricture development. Chronic inflammation is a prerequisite, but progression to strictures involves changes in fibroblasts, myofibroblasts and smooth muscle cells in a poorly understood interplay with immune cells and environmental cues. Much of the experimental evidence available is from animal models, cell lines or non-strictured patient tissue. Accordingly, these limitations create the basis for many previously published reviews covering the topic. Although this information has contributed to the understanding of fibrotic mechanisms in general, in the end, data must be validated in strictured tissue from patients. As stricture formation is a serious complication of CD, we endeavoured to summarize findings exclusively performed using strictured tissue from patients. Here, we give an update of the mechanism driving this serious complication in patients, and how the strictured tissue differs from adjacent unaffected tissue and controls.
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| 4. |
- Caër, Charles, et al.
(author)
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Human Intestinal Mononuclear Phagocytes in Health and Inflammatory Bowel Disease
- 2020
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In: Frontiers in Immunology. - : Frontiers Media SA. - 1664-3224. ; 11
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Journal article (peer-reviewed)abstract
- Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is a complex immune-mediated disease of the gastrointestinal tract that increases morbidity and negatively influences the quality of life. Intestinal mononuclear phagocytes (MNPs) have a crucial role in maintaining epithelial barrier integrity while controlling pathogen invasion by activating an appropriate immune response. However, in genetically predisposed individuals, uncontrolled immune activation to intestinal flora is thought to underlie the chronic mucosal inflammation that can ultimately result in IBD. Thus, MNPs are involved in fine-tuning mucosal immune system responsiveness and have a critical role in maintaining homeostasis or, potentially, the emergence of IBD. MNPs include monocytes, macrophages and dendritic cells, which are functionally diverse but highly complementary. Despite their crucial role in maintaining intestinal homeostasis, specific functions of human MNP subsets are poorly understood, especially during diseases such as IBD. Here we review the current understanding of MNP ontogeny, as well as the recently identified human intestinal MNP subsets, and discuss their role in health and IBD.
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| 5. |
- Caër, Charles, et al.
(author)
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TREM-1+ Macrophages Define a Pathogenic Cell Subset in the Intestine of Crohn's Disease Patients
- 2021
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In: Journal of Crohn's & colitis. - : Oxford University Press (OUP). - 1876-4479 .- 1873-9946. ; 15:8, s. 1346-1361
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Journal article (peer-reviewed)abstract
- BACKGROUND AND AIMS: Uncontrolled activation of intestinal mononuclear phagocytes [MNPs] drives chronic inflammation in inflammatory bowel disease [IBD]. Triggering receptor expressed on myeloid cells 1 [TREM-1] has been implicated in the pathogenesis of IBD. However, the role of TREM-1+ cell subsets in driving IBD pathology and the link with clinical parameters are not understood. We investigated TREM-1 expression in human intestinal MNP subsets and examined blocking TREM-1 as a potential IBD therapy. METHODS: TREM-1 gene expression was analysed in intestinal mucosa, enriched epithelial and lamina propria [LP] layers, and purified cells from controls and IBD patients. TREM-1 protein on immune cells was assessed by flow cytometry and immunofluorescence microscopy. Blood monocyte activation was examined by large-scale gene expression using a TREM-1 agonist or LP conditioned media [LP-CM] from patients in the presence or absence of TREM-1 and tumour necrosis factor [TNF] antagonist antibodies. RESULTS: TREM-1 gene expression increases in intestinal mucosa from IBD patients and correlates with disease score. TREM-1+ cells, which are mainly immature macrophages and CD11b+ granulocytes, increase among LP cells from Crohn's disease patients and their frequency correlates with inflammatory molecules in LP-CM. LP-CM from Crohn's disease patients induces an inflammatory transcriptome in blood monocytes, including increased IL-6 expression, which is reduced by simultaneous blocking of TREM-1 and TNF. CONCLUSIONS: High intestinal TREM-1 expression, reflecting a high frequency of TREM-1+ immature macrophages and TREM-1+CD11b+ granulocytes, is linked to the deleterious inflammatory microenvironment in IBD patients. Therefore, blocking the TREM-1 pathway, especially simultaneously with anti-TNF therapy, has potential as a new IBD therapy.
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| 6. |
- Wick, Mary Jo, 1963, et al.
(author)
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Remembering Nils Lycke (1954-2022)
- 2023
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In: Scandinavian Journal of Immunology. - : Wiley. - 1365-3083 .- 0300-9475. ; 97:1
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Journal article (peer-reviewed)
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