| 4. |
- Poupeau, A., et al.
(författare)
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Genes controlling the activation of natural killer lymphocytes are epigenetically remodeled in intestinal cells from germ-free mice
- 2019
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Ingår i: Faseb Journal. - 0892-6638. ; 33:2, s. 2719-2731
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Tidskriftsartikel (refereegranskat)abstract
- Remodeling of the gut microbiota is implicated in various metabolic and inflammatory diseases of the gastrointestinal tract. We hypothesized that the gut microbiota affects the DNA methylation profile of intestinal epithelial cells (IECs) which could, in turn, alter intestinal function. In this study, we used mass spectrometry and methylated DNA capture to respectively investigate global and genome-wide DNA methylation of intestinal epithelial cells from germ-free (GF) and conventionally raised mice. In colonic IECs from GF mice, DNA was markedly hypermethylated. This was associated with a dramatic loss of ten-eleven-translocation activity, a lower DNA methyltransferase activity and lower circulating levels of the 1-carbon metabolite, folate. At the gene level, we found an enrichment for differentially methylated regions proximal to genes regulating the cytotoxicity of NK cells (false-discovery rate < 8.9E(-6)), notably genes regulating the cross-talk between NK cells and target cells, such as members of the NK group 2 member D ligand superfamily Raet. This distinct epigenetic signature was associated with a marked decrease in Raet1 expression and a loss of CD56(+)/CD45(+) cells in the intestine of GF mice. Thus, our results indicate that altered activity of methylation-modifying enzymes in GF mice influences the IEC epigenome and modulates the crosstalk between IECs and NK cells. Epigenetic reprogramming of IECs may modulate intestinal function in diseases associated with altered gut microbiota.Poupeau, A., Garde, C., Sulek, K., Citirikkaya, K., Treebak, J. T., Arumugam, M., Simar, D., Olofsson, L. E., Backhed, F., Barres, R. Genes controlling the activation of natural killer lymphocytes are epigenetically remodeled in intestinal cells from germ-free mice.
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| 5. |
- Graae, Anne-Sofie, et al.
(författare)
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ADAMTS9 Regulates Skeletal Muscle Insulin Sensitivity Through Extracellular Matrix Alterations
- 2019
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Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 68:3, s. 502-514
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Tidskriftsartikel (refereegranskat)abstract
- The ADAMTS9 rs4607103 C allele is one of the few gene variants proposed to increase the risk of type 2 diabetes through an impairment of insulin sensitivity. We show that the variant is associated with increased expression of the secreted ADAMTS9 and decreased insulin sensitivity and signaling in human skeletal muscle. In line with this, mice lacking Adamts9 selectively in skeletal muscle have improved insulin sensitivity. The molecular link between ADAMTS9 and insulin signaling was characterized further in a model where ADAMTS9 was overexpressed in skeletal muscle. This selective over expression resulted in decreased insulin signaling presumably mediated through alterations of the integrin 131 signaling pathway and disruption of the intracellular cytoskeletal organization. Furthermore, this led to impaired mitochondria! function in mouse muscle-an observation found to be of translational character because humans carrying the ADAMTS9 risk allele have decreased expression of mitochondrial markers. Finally, we found that the link between ADAMTS9 overexpression and impaired insulin signaling could be due to accumulation of harmful lipid intermediates. Our findings contribute to the understanding of the molecular mechanisms underlying insulin resistance and type 2 diabetes and point to inhibition of ADAMTS9 as a potential novel mode of treating insulin resistance.
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