The Experts below are selected from a list of 2817 Experts worldwide ranked by ideXlab platform
Shiu-huey Chou - One of the best experts on this subject based on the ideXlab platform.
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Protection of Bone Marrow-Derived CD45(superscript +)/CD34(superscript -)/lin(superscript -) Stromal Cells with Immunosuppressant Activity against Ischemia/Reperfusion Injury in Rats
The Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
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protection of bone marrow derived cd45 superscript cd34 superscript lin superscript stromal cells with Immunosuppressant Activity against ischemia reperfusion injury in rats
Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
Yuan-chang Chung - One of the best experts on this subject based on the ideXlab platform.
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Protection of Bone Marrow-Derived CD45(superscript +)/CD34(superscript -)/lin(superscript -) Stromal Cells with Immunosuppressant Activity against Ischemia/Reperfusion Injury in Rats
The Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
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protection of bone marrow derived cd45 superscript cd34 superscript lin superscript stromal cells with Immunosuppressant Activity against ischemia reperfusion injury in rats
Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
Han-sun Chiang - One of the best experts on this subject based on the ideXlab platform.
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Protection of Bone Marrow-Derived CD45(superscript +)/CD34(superscript -)/lin(superscript -) Stromal Cells with Immunosuppressant Activity against Ischemia/Reperfusion Injury in Rats
The Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
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protection of bone marrow derived cd45 superscript cd34 superscript lin superscript stromal cells with Immunosuppressant Activity against ischemia reperfusion injury in rats
Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
Bo-yang Huang - One of the best experts on this subject based on the ideXlab platform.
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Protection of Bone Marrow-Derived CD45(superscript +)/CD34(superscript -)/lin(superscript -) Stromal Cells with Immunosuppressant Activity against Ischemia/Reperfusion Injury in Rats
The Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
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protection of bone marrow derived cd45 superscript cd34 superscript lin superscript stromal cells with Immunosuppressant Activity against ischemia reperfusion injury in rats
Chinese Journal of Physiology, 2011Co-Authors: Yuan-chang Chung, Bo-yang Huang, Han-sun Chiang, Shiu-huey ChouAbstract:Non-hematopoietic CD45(superscript +) precursor cells are not known to differentiate into cardiomyocytes. We found that CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells isolated from mouse bone marrow (BMSCs) potentially differentiated into cardiomyocyte-like cells in vitro. Therefore, we hypothesized that the CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs might protect rat hearts against ischemia/reperfusion (IR) injury following xeno-transplantation. In the present study, BMSCs were isolated by immunoselection and their cellular phenotype and biochemical properties were characterized. The immunological inertness of BMSCs was examined by the allogeneic and xenogeneic mixed lymphocyte reaction (MLR). The potential role of BMSCs for cardioprotection was evaluated by intravenous introduction of 1×10^6 cells into rat IR hearts, induced by left coronary ligation for 45 min and released for 72 h. Changes in cardiac contractility and the degree of myocardial injury were assessed. Our findings indicated that BMSCs expressed the muscle-cell marker-actinin after 5-azacytidine treatment. CD45(superscript +)/CD34(superscript -)/lin(superscript -) stromal cells were characterized as mesenchymal progenitor cells based on the expression of Sca-1 and Rex-1. The MLR assay revealed an immunosuppression of BMSCs on mouse and rat lymphocytes. After xeno-transplantation, the BMSCs engrafted into the infarct area and attenuated IR injury. However, increases in intracardial TGF-βand IFN-γ contents of IR hearts were not affected by BMSC treatment. Interestingly, ex vivo evidence indicated that CXCR4, SDF-1 and TGFβ-1 receptors were up-regulated after the cells were exposed to tissue extracts prepared from rat post-IR hearts. In addition, IFN-γ treatment also markedly increased Sca-1 expression in BMSCs. Mechanistically, these results indicated that CXCR4/SDF-1 and TGF-β signals potentially enhanced the interaction of BMSCs with the damaged myocardium, and increased IFN-γ in post-ischemic hearts might cause BMSC to behave more like stem cells in cardioprotection. These data show that CD45(superscript +)/CD34(superscript -)/lin(superscript -) BMSCs possess cardioprotective capacity. Evidently, the accurate production of soluble factors TGF-β and IFN-γ in parallel with increased expression of both TGF-β and Sca-1 receptors may favor BMSCs to achieve a more efficient protective capacity.
Jianping Wen - One of the best experts on this subject based on the ideXlab platform.
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Identification of the regulon FkbN for ascomycin biosynthesis and its interspecies conservation analysis as LAL family regulator
Biochemical Engineering Journal, 2019Co-Authors: Yue Zhang, Hong Chen, Pan Wang, Jianping WenAbstract:Abstract Ascomycin is a 23-membered polyketide macrolide with high Immunosuppressant Activity, produced by Streptomyces hygroscopicus var. ascomyceticus. However, the specific regulatory mechanism of the ascomycin biosynthesis pathway remains poorly understood. Here, we show that FkbN is a pathway-specific positive regulator for the ascomycin biosynthesis. Inactivation of fkbN led to a complete loss of ascomycin production ability. Compared with the parental strain, the ascomycin yield of a constructed fkbN overexpression strain increased by 400%–1800 mg/L. Transcriptional levels of the genes of encoding precursor, PKS (polyketide synthase) and NRPS (nonribosomal peptide synthetases) were blocked in the fkbN in-frame deletion strain and greatly upregulated in the fkbN overexpression strain. Electrophoretic mobility shift assays (EMSAs) revealed that FkbN-DBD protein specifically bound to the intergenic regions of fkbR1-fkbE and fkbB-fkbO. To explore the high conservation among regulators homologous to FkbN, EMSAs showed that the FkbN-DBD protein directly bound to the putative promoters of different macrolide biosynthetic gene clusters. We did further study in the fkbN deletion strain by heterologous genetic complementation with single copy of the homologous LAL family regulators. Results showed that all the heterologous complementation strains restored the production of ascomycin. Introduction of a single copy of fkbN into the tacrolimus producing strain S. tsukubaensis or rapamycin producing strain S. hygroscopicus, respectively, both enhanced the yields of the corresponding antibiotics.
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Insights into the metabolic mechanism of rapamycin overproduction in the shikimate-resistant Streptomyces hygroscopicus strain UV-II using comparative metabolomics.
World Journal of Microbiology and Biotechnology, 2017Co-Authors: Huiyan Geng, Cheng Wang, Jiao Liu, Huanhuan Liu, Jianping WenAbstract:Rapamycin is a polyketide with a 31-membered macrolide ring that possesses powerful Immunosuppressant Activity. In this study, we firstly obtained a mutant, shikimate-resistant Streptomyces hygroscopicus strain UV-II, which displayed about 3.20-fold higher rapamycin production (305.9 mg/L) than the wild-type S. hygroscopicus ATCC29253 (95.5 mg/L). Under optimal conditions, with the addition of 2 g/L shikimic acid, the strain’s rapamycin production was further increased by approximately 34.9%, to 412.6 mg/L. To gain deeper insights into the effects of shikimic acid resistance and supplementation, the fermentation properties, metabolite concentrations, and transcriptional levels of relevant genes were analyzed and evaluated for differences between this improved mutant and its parental strain. The results showed that most of the metabolic modules involved in rapamycin biosynthesis were upregulated in the mutant strain. Analysis of metabolic pathways and gene expression levels further revealed that shikimic acid metabolism plays a crucial role in the synthesis of rapamycin, and identified the rapK gene as a potential target for genetic manipulation to obtain rapamycin-producing strains with improved product yield. Consequently, the rapK gene was overexpressed in the UV-II strain, which to our delight further improved rapamycin production to 457.3 mg/L. These findings thus provide a theoretical basis for further improvements in the production of not only rapamycin, but also of other, analogous macrolide compounds.
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A genome-scale dynamic flux balance analysis model of Streptomyces tsukubaensis NRRL18488 to predict the targets for increasing FK506 production
Biochemical Engineering Journal, 2017Co-Authors: Cheng Wang, Jiao Liu, Huanhuan Liu, Junhua Wang, Jianping WenAbstract:Abstract FK506 is a 23-membered polyketide macrolide with a good Immunosuppressant Activity for the treatment of autoimmune diseases. However, the low fermentation yield is a bottleneck to limit its further industrialization and clinical applications. To address this issue, a genome-scale dynamic flux balance analysis (GS-DFBA) model was developed to seek for the bottlenecks of FK506 biosynthesis. After validating under different cultural conditions, lots of targets were predicted successfully with help of Minimization of Metabolic Adjustment (MOMA). Specifically, many uncover targets that heretofore had remained hidden in the complex interconnectedness of central metabolism had also shown significant effects on FK506 accumulation. To validate the model predictions, four identified targets (gcdh, tktB, msdh and ask gene) were engineered in Streptomyces tsukubaensis NRRL18488. All of the engineered strains showed a higher FK506 production, compared with the parent strain. Finally, the best strain HT-△gcdh-tktB/msdh/ask with gcdh-deletion and tktB-, msdh- and ask-overexpression could produce 126.61 ± 4.66 mg/L FK506, 129.8% higher than that of the wild-type strain (55.1 ± 3.83 mg/L). Results demonstrated that the GS-DFBA model could provide an effective approach in engineering S. tsukubaensis NRRL18488 for FK506 overproduction. This strategy developed here could also be extended to titer improvement of other products.