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- Ahi, Ehsan Pashay, et al.
(författare)
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Appetite regulating genes in zebrafish gut; a gene expression study
- 2022
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 17:7
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Tidskriftsartikel (refereegranskat)abstract
- The underlying molecular pathophysiology of feeding disorders, particularly in peripheral organs, is still largely unknown. A range of molecular factors encoded by appetite-regulating genes are already described to control feeding behaviour in the brain. However, the important role of the gastrointestinal tract in the regulation of appetite and feeding in connection to the brain has gained more attention in the recent years. An example of such inter-organ connection can be the signals mediated by leptin, a key regulator of body weight, food intake and metabolism, with conserved anorexigenic effects in vertebrates. Leptin signals functions through its receptor (lepr) in multiple organs, including the brain and the gastrointestinal tract. So far, the regulatory connections between leptin signal and other appetite-regulating genes remain unclear, particularly in the gastrointestinal system. In this study, we used a zebrafish mutant with impaired function of leptin receptor to explore gut expression patterns of appetite-regulating genes, under different feeding conditions (normal feeding, 7-day fasting, 2 and 6-hours refeeding). We provide evidence that most appetite-regulating genes are expressed in the zebrafish gut. On one hand, we did not observed significant differences in the expression of orexigenic genes (except for hcrt) after changes in the feeding condition. On the other hand, we found 8 anorexigenic genes in wild-types (cart2, cart3, dbi, oxt, nmu, nucb2a, pacap and pomc), as well as 4 genes in lepr mutants (cart3, kiss1, kiss1r and nucb2a), to be differentially expressed in the zebrafish gut after changes in feeding conditions. Most of these genes also showed significant differences in their expression between wild-type and lepr mutant. Finally, we observed that impaired leptin signalling influences potential regulatory connections between anorexigenic genes in zebrafish gut. Altogether, these transcriptional changes propose a potential role of leptin signal in the regulation of feeding through changes in expression of certain anorexigenic genes in the gastrointestinal tract of zebrafish.
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| 2. |
- Chen, Junyu
(författare)
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Novel biomarkers in regulating human dense connective tissue repair
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Painful and degenerative disorders of the musculoskeletal system pose a tremendous burden on the healthcare system. One main reason is the limited knowledge of the underlying key factors and pathways responsible for the suboptimal and often varying healing outcomes of dense connective tissues (CTs), such as tendons, ligaments and knee meniscus, which have vital supportive, protective and force transmitting roles in the human body. The overall aim of this thesis was to identify novel biomarkers of dense CT healing. The thesis was designed to explore for biomarkers during the inflammatory- and proliferative healing phases in tissue biopsies and micro-dialysate, respectively, after Achilles tendon rupture (ATR) as a model of dense CT healing. Using quantitative RT-PCR and immunohistochemistry of ATR tissue biopsies from the inflammatory healing phase the presence of potential biomarkers (Col I, Col III, FGF, FN, MMP-9) was identified. The gene expression of fibroblast growth factor (FGF) was positively associated with improved 1-year patient-reported- and functional outcomes. Higher Col III mRNA expression was associated with more perceived tendon strength at 1 year. Proteomic profiling using quantitative mass spectrometry of ATR biopsies from the inflammatory healing phase disclosed 769 proteins, including 51 differentially expressed proteins among patients with good- versus poor 1-year outcome. Among them a novel biomarker, elongation factor-2 (eEF2), was identified as being strongly prognostic of the 1-year clinical outcome. Experimental exploration revealed that eEF2 regulated autophagy, cell proliferation and migration, as well as reduced cell death and apoptosis in dense CT healing. Utilizing the proteomic profile from the inflammatory healing phase together with weighted co-expression network analysis a biomarker, inter-alpha-trypsin inhibitor heavy chain (ITIH4), associated with improved 1-year healing outcomes was discovered. Experimental explorations identified ITIH4 to stimulate collagen I production mediated by PPARγ signaling pathways. Further proteomic profiling of micro-dialysate from the proliferative healing phase discovered 1288 unique proteins, whereof 9 upregulated, and 23 downregulated proteins in patients with good- versus poor 1-year outcome. Upregulated proteins were related mainly to extracellular matrix organization, while downregulated pathways were associated with functions such as thrombosis formation. The most reliable predictive biomarker was the downregulated pro-inflammatory complement factor D (CFD). Expanded characterization of CFD demonstrated higher expression during inflammatory- and lower expression during proliferative healing phases in the good outcome patients. Further experimental explorations demonstrated that CFD improved repair by enhancing cell migration and collagen type I (Col1a1) production during inflammation, while exerting the opposite effects during proliferative healing. The results of this thesis have established biomarkers eEF2, FGF, ITIH4 during the inflammatory healing phase and CFD mainly during the proliferative healing phase, all prognostic of improved patient outcome in tendon repair, presumably reflective of dense CT healing in general. These findings may lead to improved individualized treatment decisions, as well as accelerate the development of improved therapies to promote good long-term clinical healing outcomes.
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