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- Cederlund, A, et al.
(författare)
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Label-free quantitative mass spectrometry reveals novel pathways involved in LL-37 expression
- 2014
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Ingår i: Journal of innate immunity. - : S. Karger AG. - 1662-8128 .- 1662-811X. ; 6:3, s. 365-376
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Tidskriftsartikel (refereegranskat)abstract
- Antimicrobial peptides are important for a healthy host-microbe homeostasis. In infections characterized by low levels of the human cathelicidin, LL-37, induction of its expression increases clearance of pathogens. Our aim was to discover signaling pathways and compounds capable of affecting the expression of LL-37. We recently observed a synergistic induction of LL-37 expression by stimulating the colonic epithelial cell-line HT-29 with lactose and phenylbutyrate (PBA). Here, we studied regulatory circuits mediating this synergism in HT-29 cells stimulated with lactose (60 g/l) and PBA (2 m<smlcap>M</smlcap>) for 24 h by using mass spectrometry and pathway analyses. Selected pathways were evaluated for their involvement in LL-37 regulation in a <i>CAMP</i> gene-luciferase reporter system. Three pathways were examined in detail: thyroid hormone receptor and retinoid X receptor (TR/RXR) activation, eicosanoid signaling and steroid biosynthesis. Induced expression of LL-37 was observed upon stimulation with triiodothyronine (T3, 2.5 n<smlcap>M</smlcap>-1 µ<smlcap>M</smlcap> for 3-30 h) and thyroxine (T4, 2.5-10 n<smlcap>M</smlcap> for 24 h). Furthermore, the synergism of lactose and PBA was reduced in cells coincubated with inhibitors of phospholipase A2, cyclooxygenase 2 or HMG-CoA reductase. Based on these results, we conclude that proteomics and pathway analyses are valuable tools for dissecting the regulatory networks involved in LL-37 expression.
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| 2. |
- Nylen, F, et al.
(författare)
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Boosting innate immunity: development and validation of a cell-based screening assay to identify LL-37 inducers
- 2014
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Ingår i: Innate immunity. - : SAGE Publications. - 1753-4267 .- 1753-4259. ; 20:4, s. 364-376
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Tidskriftsartikel (refereegranskat)abstract
- Innate immunity, the front line of our defence against pathogens, relies, to a great extent, on the production of antimicrobial peptides (AMPs). These peptides exhibit antimicrobial activity and immunomodulatory properties. In humans, AMPs include the defensins (α- and β-families) and the cathelicidin, LL-37. Bacterial resistance against antibiotics is a growing concern, and novel antimicrobial strategies are needed urgently. Hence, the concept of strengthening immune defences against infectious microbes by inducing AMP expression may represent novel or complementary pharmaceutical interventions in the treatment or prevention of infections. We have developed and validated a robust cell-based reporter assay for LL-37 expression, which serves as a marker for a healthy epithelial barrier. This reporter assay can be a powerful tool for high-throughput screenings. We first employed our assay to screen a panel of histone deacetylase inhibitors and derivatives, and then the Prestwick Chemical Library of Food and Drug Administration-approved compounds. After hit confirmation and independent validation in the parental cell line we identified five novel inducers of LL-37. This reporter assay will help to identify novel drug candidates for the treatment and prevention of infections. Importantly, the pattern of hits obtained may suggest cellular pathways and key mediators involved in the regulation of AMP expression.
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