Objective To examine the role of Cd-induced reactive oxygen species（ROS） generation in the apoptosis of neuronal cells. Methods Neuronal cells（primary rat cerebral cortical neurons and PC12 cells） were incubated w...Objective To examine the role of Cd-induced reactive oxygen species（ROS） generation in the apoptosis of neuronal cells. Methods Neuronal cells（primary rat cerebral cortical neurons and PC12 cells） were incubated with or without Cd post-pretreatment with rapamycin（Rap） or N-acetyl-L-cysteine（NAC）. Cell viability was determined by MTT assay, apoptosis was examined using flow cytometry and fluorescence microscopy, and the activation of phosphoinositide 3’-kinase/protein kinase B（Akt）/mammalian target of rapamycin（m TOR） and mitochondrial apoptotic pathways were measured by western blotting or immunofluorescence assays. Results Cd-induced activation of Akt/m TOR signaling, including Akt, m TOR, p70 S6 kinase（p70 S6K）, and eukaryotic initiation factor 4E binding protein 1（4E-BP1）. Rap, an m TOR inhibitor and NAC, a ROS scavenger, blocked Cd-induced activation of Akt/m TOR signaling and apoptosis of neuronal cells. Furthermore, NAC blocked the decrease of B-cell lymphoma 2/Bcl-2 associated X protein（Bcl-2/Bax） ratio, release of cytochrome c, cleavage of caspase-3 and poly（ADP-ribose） polymerase（PARP）, and nuclear translocation of apoptosis-inducing factor（AIF） and endonuclease G（Endo G）. Conclusion Cd-induced ROS generation activates Akt/m TOR and mitochondrial pathways, leading to apoptosis of neuronal cells. Our findings suggest that m TOR inhibitors or antioxidants have potential for preventing Cd-induced neurodegenerative diseases.展开更多
AIM To investigate the underlying mechanism by which CXCL12 and CXCL6 influences the metastatic potential of colon cancer and internal relation of colon cancer and stromal cells. METHODS Western blotting was used to d...AIM To investigate the underlying mechanism by which CXCL12 and CXCL6 influences the metastatic potential of colon cancer and internal relation of colon cancer and stromal cells. METHODS Western blotting was used to detect the expression of CXCL12 and CXCL6 in colon cancer cells and stromal cells. The co-operative effects of CXCL12 and CXCL6 on proliferation and invasion of colon cancer cells and human umbilical vein endothelial cells(HUVECs) were determined by enzyme-linked immunosorbent assay,and proliferation and invasion assays. The angiogenesis of HUVECs through interaction with cancer cells and stromal cells was examined by angiogenesis assay. We eventually investigated activation of PI3K/Akt/m TOR signaling by CXCL12 involved in the metastatic process of colon cancer.RESULTS CXCL12 was expressed in DLD-1 cancer cells and fibroblasts. The secretion level of CXCL6 by colon cancer cells and HUVECs were significantly promoted by fibroblasts derived from CXCL12. CXCL6 and CXCL2 could significantly enhance HUVEC proliferation and migration(P < 0.01). CXCL6 and CXCL2 enhanced angiogenesis by HUVECs when cultured with fibroblast cells and colon cancer cells(P < 0.01). CXCL12 also enhanced the invasion of colon cancer cells. Stromal cell-derived CXCL12 promoted the secretion level of CXCL6 and co-operatively promoted metastasis of colon carcinoma through activation of the PI3K/Akt/m TOR pathway.CONCLUSION Fibroblast-derived CXCL12 enhanced the CXCL6 secretion of colon cancer cells,and both CXCL12 and CXCL6 co-operatively regulated the metastasis via the PI3K/Akt/m TOR signaling pathway. Blocking this pathway may be a potential anti-metastatic therapeutic target for patients with colon cancer.展开更多
Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPKm TOR signaling pathway regulates the activation of the autophagy pathway through the c...Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPKm TOR signaling pathway regulates the activation of the autophagy pathway through the coordinated phosphorylation of ULK1. In this study, we investigated the mechanisms underlying the neuroprotective effect of puerarin and its role in modulating autophagy via the AMPK-m TOR-ULK1 signaling pathway in the rat middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. Rats were intraperitoneally injected with puerarin, 50 or 100 mg/kg, daily for 7 days. Then, 30 minutes after the final administration, rats were subjected to transient middle cerebral artery occlusion for 90 minutes. Then, after 24 hours of reperfusion, the Longa score and infarct volume were evaluated in each group. Autophagosome formation was observed by transmission electron microscopy. LC3, Beclin-1 p62, AMPK, m TOR and ULK1 protein expression levels were examined by immunofluorescence and western blot assay. Puerarin substantially reduced the Longa score and infarct volume, and it lessened autophagosome formation in the hippocampal CA1 area following cerebral ischemia/reperfusion injury in a dose-dependent manner. Pretreatment with puerarin（50 or 100 mg/kg） reduced Beclin-1 expression and the LC3-II/LC3-I ratio, as well as p-AMPK and p S317-ULK1 levels. In comparison, it increased p62 expression. Furthermore, puerarin at 100 mg/kg dramatically increased the levels of p-m TOR and p S757-ULK1 in the hippocampus on the ischemic side. Our findings suggest that puerarin alleviates autophagy by activating the APMK-m TOR-ULK1 signaling pathway. Thus, puerarin might have therapeutic potential for treating cerebral ischemia/reperfusion injury.展开更多
Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and af...Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.展开更多
Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its ...Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its early diagnosis and treatment for RCC.microRNA(miRNA)data of M2-EVs and RCC were searched on the Gene Expression Omnibus database,followed by the prediction of the potential downstream target.Expression of target genes was measured via RT-qPCR and Western blot,respectively.M2 macrophage was obtained viaflow cytometry with M2-EVs extracted.The binding ability of miR-342-3p to NEDD4L and to CEP55 ubiquitination was studied with their roles in the physical abilities of RCC cells assayed.Subcutaneous tumor-bearing mouse models and lung metastasis models were prepared to observe in vivo role of target genes.M2-EVs induced RCC growth and metastasis.miR-342-3p showed high expression in both M2-EVs and RCC cells.M2-EVs carrying miR-342-3p promoted RCC cell abilities to proliferate,invade and migrate.In RCC cells,M2-EV-derived miR-342-3p could specifically bind to NEDD4L and consequently elevate CEP55 protein expression via suppressing NEDD4L,thereby exerting tumor-promoting effects.CEP55 could be degraded by ubiquitination under the function of NEDD4L,and miR-342-3p delivered by M2-EVs facilitated the RCC occurrence and development by activating the PI3K/AKT/mTOR signaling pathway.In conclusion,M2-EVs promote RCC growth and metastasis by delivering miR-342-3p to suppress NEDD4L and subsequently inhibit CEP55 ubiquitination and degradation via activation of the PI3K/AKT/mTOR signaling pathway,strongly driving the proliferative,migratory and invasive of RCC cells.展开更多
Gray mouse lemurs（Microcebus murinus） from Madagascar present an excellent model for studies of torpor regulation in a primate species. In the present study, we analyzed the response of the insulin signaling pathway...Gray mouse lemurs（Microcebus murinus） from Madagascar present an excellent model for studies of torpor regulation in a primate species. In the present study, we analyzed the response of the insulin signaling pathway as well as controls on carbohydrate sparing in six different tissues of torpid versus aroused gray mouse lemurs. We found that the relative level of phospho-insulin receptor substrate（IRS-1） was significantly increased in muscle, whereas the level of phospho-insulin receptor（IR） was decreased in white adipose tissue（WAT） of torpid animals, both suggesting an inhibition of insulin/insulin-like growth factor-1（IGF-1） signaling during torpor in these tissues. By contrast, the level of phospho-IR was increased in the liver. Interestingly, muscle,WAT, and liver occupy central roles in whole body homeostasis and each displays regulatory controls operating at the plasma membrane. Changes in other tissues included an increase in phosphoglycogen synthase kinase 3a（GSK3a） and decrease in phospho-ribosomal protein S6（RPS6） in the heart, and a decrease in phospho-mammalian target of rapamycin（m TOR） in the kidney. Pyruvate dehydrogenase（PDH） that gates carbohydrate entry into mitochondria is inhibited via phosphorylation by pyruvate dehydrogenase kinase（e.g., PDK4）. In the skeletal muscle, the protein expression of PDK4 and phosphorylated PDH at Ser 300 was increased, suggesting inhibition during torpor. In contrast, there were no changes in levels of PDH expression and phosphorylation in other tissues comparing torpid and aroused animals. Information gained from these studies highlight the molecular controls that help to regulate metabolic rate depression and balance energetics during primate torpor.展开更多
基金supported by the National Natural Science Foundation of China(No.31101866 and 31302058)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China Postdoctoral Science Foundation funded project(2015M581874)Jiangsu Planned Projects for Postdoctoral Research Funds(1501072A)
文摘Objective To examine the role of Cd-induced reactive oxygen species（ROS） generation in the apoptosis of neuronal cells. Methods Neuronal cells（primary rat cerebral cortical neurons and PC12 cells） were incubated with or without Cd post-pretreatment with rapamycin（Rap） or N-acetyl-L-cysteine（NAC）. Cell viability was determined by MTT assay, apoptosis was examined using flow cytometry and fluorescence microscopy, and the activation of phosphoinositide 3’-kinase/protein kinase B（Akt）/mammalian target of rapamycin（m TOR） and mitochondrial apoptotic pathways were measured by western blotting or immunofluorescence assays. Results Cd-induced activation of Akt/m TOR signaling, including Akt, m TOR, p70 S6 kinase（p70 S6K）, and eukaryotic initiation factor 4E binding protein 1（4E-BP1）. Rap, an m TOR inhibitor and NAC, a ROS scavenger, blocked Cd-induced activation of Akt/m TOR signaling and apoptosis of neuronal cells. Furthermore, NAC blocked the decrease of B-cell lymphoma 2/Bcl-2 associated X protein（Bcl-2/Bax） ratio, release of cytochrome c, cleavage of caspase-3 and poly（ADP-ribose） polymerase（PARP）, and nuclear translocation of apoptosis-inducing factor（AIF） and endonuclease G（Endo G）. Conclusion Cd-induced ROS generation activates Akt/m TOR and mitochondrial pathways, leading to apoptosis of neuronal cells. Our findings suggest that m TOR inhibitors or antioxidants have potential for preventing Cd-induced neurodegenerative diseases.
基金Supported by National Natural Science Foundation of China,No.81260325(to Ma JC)
文摘AIM To investigate the underlying mechanism by which CXCL12 and CXCL6 influences the metastatic potential of colon cancer and internal relation of colon cancer and stromal cells. METHODS Western blotting was used to detect the expression of CXCL12 and CXCL6 in colon cancer cells and stromal cells. The co-operative effects of CXCL12 and CXCL6 on proliferation and invasion of colon cancer cells and human umbilical vein endothelial cells(HUVECs) were determined by enzyme-linked immunosorbent assay,and proliferation and invasion assays. The angiogenesis of HUVECs through interaction with cancer cells and stromal cells was examined by angiogenesis assay. We eventually investigated activation of PI3K/Akt/m TOR signaling by CXCL12 involved in the metastatic process of colon cancer.RESULTS CXCL12 was expressed in DLD-1 cancer cells and fibroblasts. The secretion level of CXCL6 by colon cancer cells and HUVECs were significantly promoted by fibroblasts derived from CXCL12. CXCL6 and CXCL2 could significantly enhance HUVEC proliferation and migration(P < 0.01). CXCL6 and CXCL2 enhanced angiogenesis by HUVECs when cultured with fibroblast cells and colon cancer cells(P < 0.01). CXCL12 also enhanced the invasion of colon cancer cells. Stromal cell-derived CXCL12 promoted the secretion level of CXCL6 and co-operatively promoted metastasis of colon carcinoma through activation of the PI3K/Akt/m TOR pathway.CONCLUSION Fibroblast-derived CXCL12 enhanced the CXCL6 secretion of colon cancer cells,and both CXCL12 and CXCL6 co-operatively regulated the metastasis via the PI3K/Akt/m TOR signaling pathway. Blocking this pathway may be a potential anti-metastatic therapeutic target for patients with colon cancer.
基金supported by the National Natural Science Foundation of China,No.81202625the Open Fund of Key Laboratory of Cardiovascular and Cerebrovascular Diseases Translational Medicine,China Three Gorges University,China,No.2016xnxg101
文摘Puerarin suppresses autophagy to alleviate cerebral ischemia/reperfusion injury, and accumulating evidence indicates that the AMPKm TOR signaling pathway regulates the activation of the autophagy pathway through the coordinated phosphorylation of ULK1. In this study, we investigated the mechanisms underlying the neuroprotective effect of puerarin and its role in modulating autophagy via the AMPK-m TOR-ULK1 signaling pathway in the rat middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. Rats were intraperitoneally injected with puerarin, 50 or 100 mg/kg, daily for 7 days. Then, 30 minutes after the final administration, rats were subjected to transient middle cerebral artery occlusion for 90 minutes. Then, after 24 hours of reperfusion, the Longa score and infarct volume were evaluated in each group. Autophagosome formation was observed by transmission electron microscopy. LC3, Beclin-1 p62, AMPK, m TOR and ULK1 protein expression levels were examined by immunofluorescence and western blot assay. Puerarin substantially reduced the Longa score and infarct volume, and it lessened autophagosome formation in the hippocampal CA1 area following cerebral ischemia/reperfusion injury in a dose-dependent manner. Pretreatment with puerarin（50 or 100 mg/kg） reduced Beclin-1 expression and the LC3-II/LC3-I ratio, as well as p-AMPK and p S317-ULK1 levels. In comparison, it increased p62 expression. Furthermore, puerarin at 100 mg/kg dramatically increased the levels of p-m TOR and p S757-ULK1 in the hippocampus on the ischemic side. Our findings suggest that puerarin alleviates autophagy by activating the APMK-m TOR-ULK1 signaling pathway. Thus, puerarin might have therapeutic potential for treating cerebral ischemia/reperfusion injury.
基金supported by American Diabetes Association,American Heart Association,NIH NIEHS,NIH NIA,NIH NINDS,and NIH ARRA
文摘Throughout the globe,diabetes mellitus（DM） is increasing in incidence with limited therapies presently available to prevent or resolve the significant complications of this disorder.DM impacts multiple organs and affects all components of the central and peripheral nervous systems that can range from dementia to diabetic neuropathy.The mechanistic target of rapamycin（m TOR） is a promising agent for the development of novel regenerative strategies for the treatment of DM.m TOR and its related signaling pathways impact multiple metabolic parameters that include cellular metabolic homeostasis,insulin resistance,insulin secretion,stem cell proliferation and differentiation,pancreatic β-cell function,and programmed cell death with apoptosis and autophagy.m TOR is central element for the protein complexes m TOR Complex 1（m TORC1） and m TOR Complex 2（m TORC2） and is a critical component for a number of signaling pathways that involve phosphoinositide 3-kinase（PI 3-K）,protein kinase B（Akt）,AMP activated protein kinase（AMPK）,silent mating type information regulation 2 homolog 1（Saccharomyces cerevisiae）（SIRT1）,Wnt1 inducible signaling pathway protein 1（WISP1）,and growth factors.As a result,m TOR represents an exciting target to offer new clinical avenues for the treatment of DM and the complications of this disease.Future studies directed to elucidate the delicate balance m TOR holds over cellular metabolism and the impact of its broad signaling pathways should foster the translation of these targets into effective clinical regimens for DM.
基金supported by the Science and Technology Department of Sichuan Province(2015SZ0117,2019YJ0701,and 2021YJ0239).
文摘Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its early diagnosis and treatment for RCC.microRNA(miRNA)data of M2-EVs and RCC were searched on the Gene Expression Omnibus database,followed by the prediction of the potential downstream target.Expression of target genes was measured via RT-qPCR and Western blot,respectively.M2 macrophage was obtained viaflow cytometry with M2-EVs extracted.The binding ability of miR-342-3p to NEDD4L and to CEP55 ubiquitination was studied with their roles in the physical abilities of RCC cells assayed.Subcutaneous tumor-bearing mouse models and lung metastasis models were prepared to observe in vivo role of target genes.M2-EVs induced RCC growth and metastasis.miR-342-3p showed high expression in both M2-EVs and RCC cells.M2-EVs carrying miR-342-3p promoted RCC cell abilities to proliferate,invade and migrate.In RCC cells,M2-EV-derived miR-342-3p could specifically bind to NEDD4L and consequently elevate CEP55 protein expression via suppressing NEDD4L,thereby exerting tumor-promoting effects.CEP55 could be degraded by ubiquitination under the function of NEDD4L,and miR-342-3p delivered by M2-EVs facilitated the RCC occurrence and development by activating the PI3K/AKT/mTOR signaling pathway.In conclusion,M2-EVs promote RCC growth and metastasis by delivering miR-342-3p to suppress NEDD4L and subsequently inhibit CEP55 ubiquitination and degradation via activation of the PI3K/AKT/mTOR signaling pathway,strongly driving the proliferative,migratory and invasive of RCC cells.
基金supported by a Discovery grant from the Natural Sciences and Engineering Research Council (NSERC) of Canada (Grant No. 6793)a grant from the Heart and Stroke Foundation of Canada (Grant No. G-14-0005874) to KBS. KBS holds the Canada Research Chair in Molecular PhysiologySNT, KKB, and CWW all held NSERC postgraduate scholarships
文摘Gray mouse lemurs（Microcebus murinus） from Madagascar present an excellent model for studies of torpor regulation in a primate species. In the present study, we analyzed the response of the insulin signaling pathway as well as controls on carbohydrate sparing in six different tissues of torpid versus aroused gray mouse lemurs. We found that the relative level of phospho-insulin receptor substrate（IRS-1） was significantly increased in muscle, whereas the level of phospho-insulin receptor（IR） was decreased in white adipose tissue（WAT） of torpid animals, both suggesting an inhibition of insulin/insulin-like growth factor-1（IGF-1） signaling during torpor in these tissues. By contrast, the level of phospho-IR was increased in the liver. Interestingly, muscle,WAT, and liver occupy central roles in whole body homeostasis and each displays regulatory controls operating at the plasma membrane. Changes in other tissues included an increase in phosphoglycogen synthase kinase 3a（GSK3a） and decrease in phospho-ribosomal protein S6（RPS6） in the heart, and a decrease in phospho-mammalian target of rapamycin（m TOR） in the kidney. Pyruvate dehydrogenase（PDH） that gates carbohydrate entry into mitochondria is inhibited via phosphorylation by pyruvate dehydrogenase kinase（e.g., PDK4）. In the skeletal muscle, the protein expression of PDK4 and phosphorylated PDH at Ser 300 was increased, suggesting inhibition during torpor. In contrast, there were no changes in levels of PDH expression and phosphorylation in other tissues comparing torpid and aroused animals. Information gained from these studies highlight the molecular controls that help to regulate metabolic rate depression and balance energetics during primate torpor.
