| 1. |
- Sigurdsson, Valgardur, et al.
(författare)
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Bile Acids Protect Expanding Hematopoietic Stem Cells from Unfolded Protein Stress in Fetal Liver.
- 2016
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Ingår i: Cell Stem Cell. - : Elsevier BV. - 1934-5909. ; 18:4, s. 32-522
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Tidskriftsartikel (refereegranskat)abstract
- During development, hematopoietic stem cells (HSCs) undergo a rapid expansion in the fetal liver (FL) before settling in the adult bone marrow. We recently reported that proliferating adult HSCs are vulnerable to ER stress caused by accumulation of mis-folded proteins. Here, we find that FL-HSCs, despite an increased protein synthesis rate and a requirement for protein folding, do not upregulate ER chaperones. Instead, bile acids (BAs), secreted from maternal and fetal liver, coordinate to serve as chemical chaperones. Taurocholic acid, the major BA in FL, supports growth of HSCs in vitro by inhibiting protein aggregation. In vivo, reducing BA levels leads to ER stress elevation and accumulation of aggregated proteins and significantly decreases the number of FL-HSCs. Taken together, these findings reveal that BA alleviation of ER stress is a mechanism required for HSC expansion during fetal hematopoiesis.
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| 2. |
- Sigurdsson, Valgardur, et al.
(författare)
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Induction of blood-circulating bile acids supports recovery from myelosuppressive chemotherapy
- 2020
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Ingår i: Blood Advances. - : American Society of Hematology. - 2473-9529 .- 2473-9537. ; 4:9, s. 1833-1843
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Tidskriftsartikel (refereegranskat)abstract
- Chemotherapeutic agents can reduce bone marrow (BM) activity, causing myelosuppression, a common life-threatening complication of cancer treatment. It is challenging to predict the patients in whom prolonged myelosuppression will occur, resulting in a delay or discontinuation of the treatment protocol. An early indicator of recovery from myelosuppression would thus be highly beneficial in clinical settings. In this study, bile acids (BAs) were highly increased in the systemic circulation as a natural response during recovery from myelosuppression, supporting regeneration of BM cells. BA levels in the blood of pediatric cancer patients and mice treated with chemotherapeutic agents were increased, in synchrony with early proliferation of BM cells and recovery from myelosuppression. In a mouse model of altered BA composition, Cyp8b1 knockout mice, a subset of mice recovered poorly after chemotherapy. The poor recovery correlated with low levels and changes in composition of BAs in the liver and systemic circulation. Conversely, BA supplementation in chemotherapy-treated wild-type mice resulted in significantly improved recovery. The results suggest that part of the mechanism by which BAs support recovery is the suppression of endoplasmic reticulum stress pathways in expanding and recovering hematopoietic cells. The findings propose a novel role of BAs as early markers of recovery and active components of the recovery process after chemotherapy.
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