Objective： To investigate the role of peroxisome proliferator-activated receptors δ （PPARδ） in inflammatory reaction and its possible mechanism in adipocyte. Methods：Lentivirus-mediated RNA interference （RNAi）...Objective： To investigate the role of peroxisome proliferator-activated receptors δ （PPARδ） in inflammatory reaction and its possible mechanism in adipocyte. Methods：Lentivirus-mediated RNA interference （RNAi） was used to block the expression of PPARδ in 3T3-L1 cells. In order to induce inflammation in 3T3-L1, cells were stimulated with tumor necrosis factor-α（TNFα, 20 ng/ml） for 4 h. The expression of PPARδ, nuclear factor κB （NFκB） and C reactive protein （CRP） were determined by Western blot analysis. Results：The expression of PPARδ was reduced by 80% after RNAi. Blockage of PPARδ promoted the expression of CRP and NFκB in cells stimulated with TNFα but had no effect on normal cells. Conclusion： PPARδ is involved in inflammatory reaction in adipocyte. Blockage of PPARδ can promote the inflammation mediated by inflammatory factors and increase the expression of NFκB and CRP in 3T3-L1 cells stimulated with TNFα.展开更多
Glucose transporter 4 (GLUT4) is responsible for insulin-stimulated glucose transporting into the insulin-sensitive fat and muscle cells. The dynamics of GLUT4 storage vesicles (GSVs) remains to be explored and it is ...Glucose transporter 4 (GLUT4) is responsible for insulin-stimulated glucose transporting into the insulin-sensitive fat and muscle cells. The dynamics of GLUT4 storage vesicles (GSVs) remains to be explored and it is unclear how GSVs are arranged based on their mobility. We examined this issue in 3T3-L1 cells via investigating the three-dimensional mobility of single GSV labeled with EGFP-fused GLUT4. A thin layer of cytosol right adjacent to the plasma membrane was illuminated and successively imaged at 5 Hz under a total internal reflection fluorescence microscope with a penetration depth of 136 nm. Employing single particle tracking, the three-dimensional subpixel displacement of single GSV was tracked at a spatial precision of 22 nm. Both the mean square displacement and the diffusion coefficient were calculated for each vesicle. Tracking results revealed that vesicles moved as if restricted within a cage that has a mean radius of 160 nm, suggesting the presence of some intracellular tethering matrix. By constructing the histogram of the diffusion coefficients of GSVs, we observed a smooth distribution instead of the existence of distinct groups. The result indicates that GSVs are dynamically retained in a continuous and wide range of mobility rather than into separate classes.展开更多
Obesity is a major human health problem associated with various diseases, including cardiac injury and type 2 diabetes. Trapa japonica Flerov (TJF) has been used in traditional oriental medicine to treat diabetes. In ...Obesity is a major human health problem associated with various diseases, including cardiac injury and type 2 diabetes. Trapa japonica Flerov (TJF) has been used in traditional oriental medicine to treat diabetes. In this study, we evaluated the inhibitory effect of and the mechanism underlying the effect of TJF extract on adipogenesis in 3T3-L1 cells. The effects of TJF extract on cell viability were analyzed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, and the anti-adipogenic effect was measured by oil red O staining. The expression of peroxisomal proliferator activated receptor (PPAR)γ, CCAAT/enhancer-binding protein-α (C/EBP)α, adenosine monophosphate-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), adiponectin, and fatty acid binding protein (FABP)4 involved in adipogenesis was determined by western blot analysis. TJF extract effectively inhibited lipid accumulation and the expression of PPARγ and C/EBPα in 3T3-L1 cells. TJF also increased the phosphorylation of AMPK and ACC, and decreased the expression of adiponectin and FABP4. These results indicate that TJF extract exerts its anti-obesity effect through the downregulation of adipogenic transcription factors and adipogenic marker genes.展开更多
Although clozapine (CZP), which is used for schizophrenia treatment, causes weight gain, the mechanism remains unclear. We recently reported that the naturally occurring compound curcumin (CUR) suppresses adipogenesis...Although clozapine (CZP), which is used for schizophrenia treatment, causes weight gain, the mechanism remains unclear. We recently reported that the naturally occurring compound curcumin (CUR) suppresses adipogenesis in 3T3-L1 cells. The aims of the present study were to determine the mechanism by which CZP induces adipocyte differentiation of 3T3-L1 cells, and whether CUR reduces CZP-induced adipogenesis. We found that cells grown in the presence of CZP had significantly higher triacylglycerol levels, numbers of lipid-filled adipocytes, and mRNA expression levels of CCAAT-enhancer binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) than those grown without CZP. Treatment with CZP plus CUR resulted in major reductions in these four parameters. These results suggest that CZP enhances adipogenesis in 3T3-L1 cells via the C/EBPα-PPARγ pathway and that by interrupting CZP’s effects, CUR might be a potent agent for preventing CZP-induced weight gain.展开更多
BACKGROUND Limonin is one of the most abundant active ingredients of Tetradium ruticarpum.It exerts antitumor effects on several kinds of cancer cells.However,whether limonin exerts antitumor effects on colorectal can...BACKGROUND Limonin is one of the most abundant active ingredients of Tetradium ruticarpum.It exerts antitumor effects on several kinds of cancer cells.However,whether limonin exerts antitumor effects on colorectal cancer(CRC)cells and cancer stem-like cells(CSCs),a subpopulation responsible for a poor prognosis,is unclear.AIM To evaluate the effects of limonin on CSCs derived from CRC cells.METHODS CSCs were collected by culturing CRC cells in serum-free medium.The cytotoxicity of limonin against CSCs and parental cells(PCs)was determined by cholecystokinin octapeptide-8 assay.The effects of limonin on stemness were detected by measuring stemness hallmarks and sphere formation ability.RESULTS As expected,limonin exerted inhibitory effects on CRC cell behaviors,including cell proliferation,migration,invasion,colony formation and tumor formation in soft agar.A relatively low concentration of limonin decreased the expression stemness hallmarks,including Nanog andβ-catenin,the proportion of aldehyde dehydrogenase 1-positive CSCs,and the sphere formation rate,indicating that limonin inhibits stemness without presenting cytotoxicity.Additionally,limonin treatment inhibited invasion and tumor formation in soft agar and in nude mice.Moreover,limonin treatment significantly inhibited the phosphorylation of STAT3 at Y705 but not S727 and did not affect total STAT3 expression.Inhibition of Nanog andβ-catenin expression and sphere formation by limonin was obviously reversed by pretreatment with 2μmol/L colievlin.CONCLUSION Taken together,these results indicate that limonin is a promising compound that targets CSCs and could be used to combat CRC recurrence and metastasis.展开更多
BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against...BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.展开更多
Vaccarin,a flavonoid glycoside isolated from Vaccaria segetalis,is non-toxic to 3T3-L1 cells up to concentrations of 200μM.Accordingly,we investigated the effects of this natural product on adipogenesis and lipolysis...Vaccarin,a flavonoid glycoside isolated from Vaccaria segetalis,is non-toxic to 3T3-L1 cells up to concentrations of 200μM.Accordingly,we investigated the effects of this natural product on adipogenesis and lipolysis in 3T3-L1 adipocytes.Our results revealed that vaccarin significantly inhibited lipid accumulation by suppressing the adipogenesis-related transcription factors peroxisome proliferator-activated receptorγ(PPARγ)and the CCAAT/enhancer-binding proteinα(C/EBPα).Specifically,lipid accumulation decreased by up to 27.7±2.7%when 3T3-L1 adipocytes were treated with a 10μM concentration of vaccarin.Mechanistic studies showed that the compound inhibited adipogenesis through activation of the Hedgehog(Hh)signaling pathway and so restoring Smo and Gli1 expression at an early stage of differentiation.In mature 3T3-L1 cells,vaccarin significantly increased the secretion of glycerol into the surrounding medium and thus indicating that it accelerated the degradation of triglycerides.In addition,vaccarin,was shown to enhance lipolysis through stimulation of the transcription levels of lipoprotein lipase,monoglycerides lipase,adipose triacylglyceride lipase,hormone-sensitive lipase and adipose differentiated-related protein.All told,vaccarin suppressed lipid accumulation and enhanced lipolysis during adipocyte differentiation by restoring Hh signaling.As such,it is a phytochemical capable of halting adipocyte hyperplasia and,thereby,ameliorating the effects of obesity.展开更多
文摘Objective： To investigate the role of peroxisome proliferator-activated receptors δ （PPARδ） in inflammatory reaction and its possible mechanism in adipocyte. Methods：Lentivirus-mediated RNA interference （RNAi） was used to block the expression of PPARδ in 3T3-L1 cells. In order to induce inflammation in 3T3-L1, cells were stimulated with tumor necrosis factor-α（TNFα, 20 ng/ml） for 4 h. The expression of PPARδ, nuclear factor κB （NFκB） and C reactive protein （CRP） were determined by Western blot analysis. Results：The expression of PPARδ was reduced by 80% after RNAi. Blockage of PPARδ promoted the expression of CRP and NFκB in cells stimulated with TNFα but had no effect on normal cells. Conclusion： PPARδ is involved in inflammatory reaction in adipocyte. Blockage of PPARδ can promote the inflammation mediated by inflammatory factors and increase the expression of NFκB and CRP in 3T3-L1 cells stimulated with TNFα.
文摘Glucose transporter 4 (GLUT4) is responsible for insulin-stimulated glucose transporting into the insulin-sensitive fat and muscle cells. The dynamics of GLUT4 storage vesicles (GSVs) remains to be explored and it is unclear how GSVs are arranged based on their mobility. We examined this issue in 3T3-L1 cells via investigating the three-dimensional mobility of single GSV labeled with EGFP-fused GLUT4. A thin layer of cytosol right adjacent to the plasma membrane was illuminated and successively imaged at 5 Hz under a total internal reflection fluorescence microscope with a penetration depth of 136 nm. Employing single particle tracking, the three-dimensional subpixel displacement of single GSV was tracked at a spatial precision of 22 nm. Both the mean square displacement and the diffusion coefficient were calculated for each vesicle. Tracking results revealed that vesicles moved as if restricted within a cage that has a mean radius of 160 nm, suggesting the presence of some intracellular tethering matrix. By constructing the histogram of the diffusion coefficients of GSVs, we observed a smooth distribution instead of the existence of distinct groups. The result indicates that GSVs are dynamically retained in a continuous and wide range of mobility rather than into separate classes.
文摘Obesity is a major human health problem associated with various diseases, including cardiac injury and type 2 diabetes. Trapa japonica Flerov (TJF) has been used in traditional oriental medicine to treat diabetes. In this study, we evaluated the inhibitory effect of and the mechanism underlying the effect of TJF extract on adipogenesis in 3T3-L1 cells. The effects of TJF extract on cell viability were analyzed using a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay, and the anti-adipogenic effect was measured by oil red O staining. The expression of peroxisomal proliferator activated receptor (PPAR)γ, CCAAT/enhancer-binding protein-α (C/EBP)α, adenosine monophosphate-activated protein kinase (AMPK), acetyl-CoA carboxylase (ACC), adiponectin, and fatty acid binding protein (FABP)4 involved in adipogenesis was determined by western blot analysis. TJF extract effectively inhibited lipid accumulation and the expression of PPARγ and C/EBPα in 3T3-L1 cells. TJF also increased the phosphorylation of AMPK and ACC, and decreased the expression of adiponectin and FABP4. These results indicate that TJF extract exerts its anti-obesity effect through the downregulation of adipogenic transcription factors and adipogenic marker genes.
文摘Although clozapine (CZP), which is used for schizophrenia treatment, causes weight gain, the mechanism remains unclear. We recently reported that the naturally occurring compound curcumin (CUR) suppresses adipogenesis in 3T3-L1 cells. The aims of the present study were to determine the mechanism by which CZP induces adipocyte differentiation of 3T3-L1 cells, and whether CUR reduces CZP-induced adipogenesis. We found that cells grown in the presence of CZP had significantly higher triacylglycerol levels, numbers of lipid-filled adipocytes, and mRNA expression levels of CCAAT-enhancer binding protein α (C/EBPα) and peroxisome proliferator-activated receptor γ (PPARγ) than those grown without CZP. Treatment with CZP plus CUR resulted in major reductions in these four parameters. These results suggest that CZP enhances adipogenesis in 3T3-L1 cells via the C/EBPα-PPARγ pathway and that by interrupting CZP’s effects, CUR might be a potent agent for preventing CZP-induced weight gain.
文摘BACKGROUND Limonin is one of the most abundant active ingredients of Tetradium ruticarpum.It exerts antitumor effects on several kinds of cancer cells.However,whether limonin exerts antitumor effects on colorectal cancer(CRC)cells and cancer stem-like cells(CSCs),a subpopulation responsible for a poor prognosis,is unclear.AIM To evaluate the effects of limonin on CSCs derived from CRC cells.METHODS CSCs were collected by culturing CRC cells in serum-free medium.The cytotoxicity of limonin against CSCs and parental cells(PCs)was determined by cholecystokinin octapeptide-8 assay.The effects of limonin on stemness were detected by measuring stemness hallmarks and sphere formation ability.RESULTS As expected,limonin exerted inhibitory effects on CRC cell behaviors,including cell proliferation,migration,invasion,colony formation and tumor formation in soft agar.A relatively low concentration of limonin decreased the expression stemness hallmarks,including Nanog andβ-catenin,the proportion of aldehyde dehydrogenase 1-positive CSCs,and the sphere formation rate,indicating that limonin inhibits stemness without presenting cytotoxicity.Additionally,limonin treatment inhibited invasion and tumor formation in soft agar and in nude mice.Moreover,limonin treatment significantly inhibited the phosphorylation of STAT3 at Y705 but not S727 and did not affect total STAT3 expression.Inhibition of Nanog andβ-catenin expression and sphere formation by limonin was obviously reversed by pretreatment with 2μmol/L colievlin.CONCLUSION Taken together,these results indicate that limonin is a promising compound that targets CSCs and could be used to combat CRC recurrence and metastasis.
文摘BACKGROUND Leukemia stem cells(LSCs)are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia(AML),as they are protected by the bone marrow microenvironment(BMM)against conventional therapies.Gossypol acetic acid(GAA),which is extracted from the seeds of cotton plants,exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.AIM To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.METHODS In this study,LSCs were magnetically sorted from AML cell lines and the CD34+CD38-population was obtained.The expression of leucine-rich pentatricopeptide repeat-containing protein(LRPPRC)and forkhead box M1(FOXM1)was evaluated in LSCs,and the effects of GAA on malignancies and mitochondrial RESULTS LRPPRC was found to be upregulated,and GAA inhibited cell proliferation by degrading LRPPRC.GAA induced LRPPRC degradation and inhibited the activation of interleukin 6(IL-6)/janus kinase(JAK)1/signal transducer and activator of transcription(STAT)3 signaling,enhancing chemosensitivity in LSCs against conventional chemotherapies,including L-Asparaginase,Dexamethasone,and cytarabine.GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC.Furthermore,GAA induced reactive oxygen species accumulation,disturbed mitochondrial homeostasis,and caused mitochondrial dysfunction.By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC,GAA resulted in the elimination of LSCs.Meanwhile,GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.CONCLUSION Taken together,the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.
基金This work was graciously supported by the Chinese National Natural Science Foundation(Grant 31901725 and 32201933)the Science and Technology Projects in Guangzhou(Grant 202201010170).
文摘Vaccarin,a flavonoid glycoside isolated from Vaccaria segetalis,is non-toxic to 3T3-L1 cells up to concentrations of 200μM.Accordingly,we investigated the effects of this natural product on adipogenesis and lipolysis in 3T3-L1 adipocytes.Our results revealed that vaccarin significantly inhibited lipid accumulation by suppressing the adipogenesis-related transcription factors peroxisome proliferator-activated receptorγ(PPARγ)and the CCAAT/enhancer-binding proteinα(C/EBPα).Specifically,lipid accumulation decreased by up to 27.7±2.7%when 3T3-L1 adipocytes were treated with a 10μM concentration of vaccarin.Mechanistic studies showed that the compound inhibited adipogenesis through activation of the Hedgehog(Hh)signaling pathway and so restoring Smo and Gli1 expression at an early stage of differentiation.In mature 3T3-L1 cells,vaccarin significantly increased the secretion of glycerol into the surrounding medium and thus indicating that it accelerated the degradation of triglycerides.In addition,vaccarin,was shown to enhance lipolysis through stimulation of the transcription levels of lipoprotein lipase,monoglycerides lipase,adipose triacylglyceride lipase,hormone-sensitive lipase and adipose differentiated-related protein.All told,vaccarin suppressed lipid accumulation and enhanced lipolysis during adipocyte differentiation by restoring Hh signaling.As such,it is a phytochemical capable of halting adipocyte hyperplasia and,thereby,ameliorating the effects of obesity.
