Heat stress(HS) has serious negative effects on plant development and has become a major threat to agriculture. A rapid transcriptional regulatory cascade has evolved in plants in response to HS. Nuclear Factor-Y(NF-Y...Heat stress(HS) has serious negative effects on plant development and has become a major threat to agriculture. A rapid transcriptional regulatory cascade has evolved in plants in response to HS. Nuclear Factor-Y(NF-Y) complexes are critical for this mechanism, but how NF-Y complexes are regulated remains unclear.In this study, we identified NF-YC10(NF-Y subunit C10), a central regulator of the HS response in Arabidopsis thaliana, as a substrate of SUMOylation, an important post-translational modification. Biochemical analysis showed that the SUMO ligase SIZ1(SAP AND MIZ1 DOMAINCONTAINING LIGASE1) interacts with NF-YC10and enhances its SUMOylation during HS. The SUMOylation of NF-YC10 facilitates its interaction with and the nuclear translocation of NF-YB3, in which the SUMO interaction motif(SIM)is essential for its efficient association with NF-YC10. Further functional analysis indicated that the SUMOylation of NF-YC10 and the SIM of NF-YB3 are critical for HS-responsive gene expression and plant thermotolerance. These findings uncover a role for the SIZ1-mediated SUMOylation of NF-YC10 in NF-Y complex assembly under HS, providing new insights into the role of a post-translational modification in regulating transcription during abiotic stress responses in plants.展开更多
Background:Pancreaticβ-cells elevate insulin production and secretion through a compensatory mechanism to override insulin resistance under metabolic stress conditions.Deficits inβ-cell compensatory capacity result ...Background:Pancreaticβ-cells elevate insulin production and secretion through a compensatory mechanism to override insulin resistance under metabolic stress conditions.Deficits inβ-cell compensatory capacity result in hyperglycemia and type 2 diabetes(T2D).However,the mechanism in the regulation ofβ-cell compensative capacity remains elusive.Nuclear factor-Y(NF-Y)is critical for pancreatic islets’homeostasis under physiological conditions,but its role inβ-cell compensatory response to insulin resistance in obesity is unclear.Methods:In this study,using obese(ob/ob)mice with an absence of NF-Y subunit A(NF-YA)inβ-cells(ob,Nf-yaβKO)as well as rat insulinoma cell line(INS1)-based models,we determined whether NF-Y-mediated apoptosis makes an essential contribution toβ-cell compensation upon metabolic stress.Results:Obese animals had markedly augmented NF-Y expression in pancreatic islets.Deletion ofβ-cell Nf-ya in obese mice worsened glucose intolerance and resulted inβ-cell dysfunction,which was attributable to augmentedβ-cell apoptosis and reactive oxygen species(ROS).Furthermore,primary pancreatic islets from Nf-yaβKO mice were sensitive to palmitate-inducedβ-cell apoptosis due to mitochondrial impairment and the attenuated antioxidant response,which resulted in the aggravation of phosphorylated c-Jun N-terminal kinase(JNK)and cleaved caspase-3.These detrimental effects were completely relieved by ROS scavenger.Ultimately,forced overexpression of NF-Y in INS1β-cell line could rescue palmitate-inducedβ-cell apoptosis,dysfunction,and mitochondrial impairment.Conclusion:Pancreatic NF-Y might be an essential regulator ofβ-cell compensation under metabolic stress.展开更多
AIM:To develop a molecular therapy for pancreatic cancer, the insulin-like growth factor-I (IGF-I) signaling pathway was analyzed.METHODS: Pancreatic cancer cell lines (MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 a...AIM:To develop a molecular therapy for pancreatic cancer, the insulin-like growth factor-I (IGF-I) signaling pathway was analyzed.METHODS: Pancreatic cancer cell lines (MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4) were cultured in media with 10 mL/L fetal bovine serum. Western blotting analysis was performed to clarify the expression of IGF-I receptor (IGF-IR). Picropodophyllin (PPP), a specific inhibitor of IGF-IR, LY294002, a specific inhibitor of phosphatidylinositol3 kinase (PI3K), and PD98059, a specific inhibitor of mitogen-activated protein kinase, were added to the media. After 72 h, a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay was performed to analyze cell proliferation. A wound assay was performed to analyze cell motility with hematoxylin and eosin (HE) staining 48 h after addition of each inhibitor. RESULTS: All cell lines clearly expressed not only IGF-IR but also phosphorylated IGF-IR. PPP significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 36.9% ± 2.4% (mean ± SD), 30.9% ± 5.5%, 23.8% ± 3.9%, 37.1% ± 5.3%, 10.4% ± 4.5%, 52.5% ± 4.5% and 22.6% ± 0.4%, at 2 μmol/L, respectively (P < 0.05). LY294002 significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 44.4% ± 7.6%, 32.9% ± 8.2%, 53.9% ± 8.0%, 52.8% ± 4.0%, 32.3% ± 4.2%, 51.8% ± 4.5%, and 30.6% ± 9.4%, at 50 μmol/L, respectively (P < 0.05). PD98059 did not significantly suppress cell proliferation. PPP at 2 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 3.0% ± 0.2%, 0%, 0%, 2.0% ± 0.1%, 5.0% ± 0.2%, 3.0% ± 0.1%, and 5.0% ± 0.2%, respectively (P < 0.05). LY294002 at 50 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 to 3.0% ± 0.2%, 0%, 3.0% ± 0.2%, 0%, 0%, 0% and 3% ± 0.1%, respectively (P < 0.05). PD980509 at 20 μmol/L did not suppress motility. Cells were observed by microscopy to analyze the morphological changes induced by the inhibitors. Cells in medium treated with 2 μmol/L PPP or 50 μmol/L LY294002 had pyknotic nuclei, whereas those in medium with 20 μmol/L PD98059 did not show apoptosis.CONCLUSION: IGF-IR and PI3K are good candidates for molecular therapy of pancreatic cancer.展开更多
基金supported by the Major Program of Guangdong Basic and Applied Research (2019B030302006)the National Natural Science Foundation of China (31871222 and 31970531)+4 种基金the Natural Science Foundation of Guangdong (2018B030 308002, 2019A1515110330, 2021A1515011151)Guangdong Modern Agro-industry Technology Research System (2021KJ114)South China Normal University Young Teachers' Research Incubation Fund Project (21KJ18)the Program for Changjiang Scholarsthe Guangdong Special Support Program of Young Top-Notch Talent in Science and Technology Innovation (2019TQ05N651)。
文摘Heat stress(HS) has serious negative effects on plant development and has become a major threat to agriculture. A rapid transcriptional regulatory cascade has evolved in plants in response to HS. Nuclear Factor-Y(NF-Y) complexes are critical for this mechanism, but how NF-Y complexes are regulated remains unclear.In this study, we identified NF-YC10(NF-Y subunit C10), a central regulator of the HS response in Arabidopsis thaliana, as a substrate of SUMOylation, an important post-translational modification. Biochemical analysis showed that the SUMO ligase SIZ1(SAP AND MIZ1 DOMAINCONTAINING LIGASE1) interacts with NF-YC10and enhances its SUMOylation during HS. The SUMOylation of NF-YC10 facilitates its interaction with and the nuclear translocation of NF-YB3, in which the SUMO interaction motif(SIM)is essential for its efficient association with NF-YC10. Further functional analysis indicated that the SUMOylation of NF-YC10 and the SIM of NF-YB3 are critical for HS-responsive gene expression and plant thermotolerance. These findings uncover a role for the SIZ1-mediated SUMOylation of NF-YC10 in NF-Y complex assembly under HS, providing new insights into the role of a post-translational modification in regulating transcription during abiotic stress responses in plants.
基金National Natural Science Foundation of China(Nos.82270846,32200933 and 81770814)National Clinical Research Center for Geriatrics,West China Hospital,Sichuan University(No.Z20201010)Sichuan Natural Science Foundation(No.23NSFSC4132)
文摘Background:Pancreaticβ-cells elevate insulin production and secretion through a compensatory mechanism to override insulin resistance under metabolic stress conditions.Deficits inβ-cell compensatory capacity result in hyperglycemia and type 2 diabetes(T2D).However,the mechanism in the regulation ofβ-cell compensative capacity remains elusive.Nuclear factor-Y(NF-Y)is critical for pancreatic islets’homeostasis under physiological conditions,but its role inβ-cell compensatory response to insulin resistance in obesity is unclear.Methods:In this study,using obese(ob/ob)mice with an absence of NF-Y subunit A(NF-YA)inβ-cells(ob,Nf-yaβKO)as well as rat insulinoma cell line(INS1)-based models,we determined whether NF-Y-mediated apoptosis makes an essential contribution toβ-cell compensation upon metabolic stress.Results:Obese animals had markedly augmented NF-Y expression in pancreatic islets.Deletion ofβ-cell Nf-ya in obese mice worsened glucose intolerance and resulted inβ-cell dysfunction,which was attributable to augmentedβ-cell apoptosis and reactive oxygen species(ROS).Furthermore,primary pancreatic islets from Nf-yaβKO mice were sensitive to palmitate-inducedβ-cell apoptosis due to mitochondrial impairment and the attenuated antioxidant response,which resulted in the aggravation of phosphorylated c-Jun N-terminal kinase(JNK)and cleaved caspase-3.These detrimental effects were completely relieved by ROS scavenger.Ultimately,forced overexpression of NF-Y in INS1β-cell line could rescue palmitate-inducedβ-cell apoptosis,dysfunction,and mitochondrial impairment.Conclusion:Pancreatic NF-Y might be an essential regulator ofβ-cell compensation under metabolic stress.
文摘AIM:To develop a molecular therapy for pancreatic cancer, the insulin-like growth factor-I (IGF-I) signaling pathway was analyzed.METHODS: Pancreatic cancer cell lines (MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4) were cultured in media with 10 mL/L fetal bovine serum. Western blotting analysis was performed to clarify the expression of IGF-I receptor (IGF-IR). Picropodophyllin (PPP), a specific inhibitor of IGF-IR, LY294002, a specific inhibitor of phosphatidylinositol3 kinase (PI3K), and PD98059, a specific inhibitor of mitogen-activated protein kinase, were added to the media. After 72 h, a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt (MTS) assay was performed to analyze cell proliferation. A wound assay was performed to analyze cell motility with hematoxylin and eosin (HE) staining 48 h after addition of each inhibitor. RESULTS: All cell lines clearly expressed not only IGF-IR but also phosphorylated IGF-IR. PPP significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 36.9% ± 2.4% (mean ± SD), 30.9% ± 5.5%, 23.8% ± 3.9%, 37.1% ± 5.3%, 10.4% ± 4.5%, 52.5% ± 4.5% and 22.6% ± 0.4%, at 2 μmol/L, respectively (P < 0.05). LY294002 significantly suppressed proliferation of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 44.4% ± 7.6%, 32.9% ± 8.2%, 53.9% ± 8.0%, 52.8% ± 4.0%, 32.3% ± 4.2%, 51.8% ± 4.5%, and 30.6% ± 9.4%, at 50 μmol/L, respectively (P < 0.05). PD98059 did not significantly suppress cell proliferation. PPP at 2 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 cells to 3.0% ± 0.2%, 0%, 0%, 2.0% ± 0.1%, 5.0% ± 0.2%, 3.0% ± 0.1%, and 5.0% ± 0.2%, respectively (P < 0.05). LY294002 at 50 μmol/L suppressed motility of MIA-Paca2, NOR-P1, PANC-1, PK-45H, PK-1, PK-59 and KP-4 to 3.0% ± 0.2%, 0%, 3.0% ± 0.2%, 0%, 0%, 0% and 3% ± 0.1%, respectively (P < 0.05). PD980509 at 20 μmol/L did not suppress motility. Cells were observed by microscopy to analyze the morphological changes induced by the inhibitors. Cells in medium treated with 2 μmol/L PPP or 50 μmol/L LY294002 had pyknotic nuclei, whereas those in medium with 20 μmol/L PD98059 did not show apoptosis.CONCLUSION: IGF-IR and PI3K are good candidates for molecular therapy of pancreatic cancer.
