Non-alcoholic fatty liver disease (NAFLD) has become a global issue and a severe threat to public health.However, to date, no approved therapeutic drugs have been developed. Dietary interventions with naturalproducts ...Non-alcoholic fatty liver disease (NAFLD) has become a global issue and a severe threat to public health.However, to date, no approved therapeutic drugs have been developed. Dietary interventions with naturalproducts have shown promise in preventing and treating NAFLD. Sulforaphane (SFN) is a phytocompoundwith antioxidant and anti-inflammatory properties, and previous research has demonstrated that SFN canameliorate hepatic lipid accumulation and inflammation. However, the molecular mechanisms underlying thesebeneficial effects remain unclear. In this study, we confirmed the protective effects of SFN on excessive lipidaccumulation and inflammatory injury in a high-fat, high-fructose diet-induced non-alcoholic steatohepatitis(NASH) mouse model. We found that SFN attenuates the inflammatory injury in a macrophage cell line andthe liver of NASH mice, owing to the promotion of M1-type macrophage polarization toward the M2-type andthe regulation of inflammatory mediators. Further analysis demonstrated that this SFN-induced macrophageM2-type polarization occurs in a Krüppel-like factor 4 (KLF4)-dependent manner. In summary, we uncovereda new mechanism of action underlying SFN activity and provide evidence that dietary intervention with SFNmight be protective against NASH.展开更多
Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key do...Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.展开更多
Salidroside is extensively used as a herbal medicine worldwide, and it has been shown to protect against disruption of endothelial homeostasis and act as an anti-aging agent. The present study aimed to investigate the...Salidroside is extensively used as a herbal medicine worldwide, and it has been shown to protect against disruption of endothelial homeostasis and act as an anti-aging agent. The present study aimed to investigate the ameliorative effects of salidroside on homocysteine (Hcy)-induced cell senescence in human umbilical vein endothelial cells (HUVECs) that were mediated via inhibition of Krüppel-like factor 4 (KLF4). An endothelial cell senescence model was induced by Hcy. The cell viability, activities of telomerase and lactate dehydrogenase (LDH), and the level of reactive oxygen species were determined using commercial kits. The expression levels of KLF4, p53 and p21 were determined via western blot analysis, whereas the mRNA expression levels of KLF4 were detected by reverse transcription-quantitative PCR. Small interfering RNA-mediated knockdown of KLF4 was found to reverse Hcy-induced cell senescence. Hcy treatment led to an accelerated cell senescence, as evidenced by decreases in both cell viability and telomerase activity, whereas increases were noted in the leakage of LDH and the level of reactive oxygen species, in addition to an up-regulation of the protein levels of p53 and p21, and up-regulation of KLF4 at both the mRNA and protein level. Treatment with salidroside ameliorated Hcy-induced cell senescence in a dose-dependent manner. Taken together, these results suggested that Hcy may induce cell senescence through upregulation of KLF4, and this may be reversed by treatment with salidroside. Therefore, salidroside was shown to inhibit Hcy-induced cell senescence through KLF4 inhibition.展开更多
Aim: Colorectal cancer (CRC) is the third leading cancer-related cause of death due to its propensity to metastasize. Epithelial-mesenchymal transition (EMT) is a multistep process important for invasion and metastasi...Aim: Colorectal cancer (CRC) is the third leading cancer-related cause of death due to its propensity to metastasize. Epithelial-mesenchymal transition (EMT) is a multistep process important for invasion and metastasis of CRC. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor highly expressed in differentiated cells of the intestinal epithelium. KLF4 has been shown to play a tumor suppressor role during CRC tumorigenesis - its loss accelerates development and progression of cancer. The present study examined the relationship between KLF4 and markers of EMT in CRC. Methods: Immunofluorescence staining for KLF4 and EMT markers was performed on archived patient samples after colorectal cancer resection and on colonic tissues of mice with colitis-associated cancer. Results: We found that KLF4 expression is lost in tumor sections obtained from CRC patients and in those of mouse colon following azoxymethane and dextran sodium sulfate (AOM/DSS) treatment when compared to their respective normal appearing mucosa. Importantly, in CRC patient tumor sections, we observed a negative correlation between KLF4 levels and mesenchymal markers including TWIST, β-catenin, claudin-1, N-cadherin, and ;vimentin. Similarly, in tumor tissues from AOM/DSS-treated mice, KLF4 levels were negatively correlated with mesenchymal markers including SNAI2, β-catenin, and vimentin and positively correlated with the epithelial marker E-cadherin. Conclusion: These findings suggest that the loss of KLF4 expression is a potentially significant indicator of EMT in CRC.展开更多
基金supported by the Science and Technology project of Henan Province(202102310142)the National Natural Science Foundation of China(32001806)。
文摘Non-alcoholic fatty liver disease (NAFLD) has become a global issue and a severe threat to public health.However, to date, no approved therapeutic drugs have been developed. Dietary interventions with naturalproducts have shown promise in preventing and treating NAFLD. Sulforaphane (SFN) is a phytocompoundwith antioxidant and anti-inflammatory properties, and previous research has demonstrated that SFN canameliorate hepatic lipid accumulation and inflammation. However, the molecular mechanisms underlying thesebeneficial effects remain unclear. In this study, we confirmed the protective effects of SFN on excessive lipidaccumulation and inflammatory injury in a high-fat, high-fructose diet-induced non-alcoholic steatohepatitis(NASH) mouse model. We found that SFN attenuates the inflammatory injury in a macrophage cell line andthe liver of NASH mice, owing to the promotion of M1-type macrophage polarization toward the M2-type andthe regulation of inflammatory mediators. Further analysis demonstrated that this SFN-induced macrophageM2-type polarization occurs in a Krüppel-like factor 4 (KLF4)-dependent manner. In summary, we uncovereda new mechanism of action underlying SFN activity and provide evidence that dietary intervention with SFNmight be protective against NASH.
基金supported by the Start-up Funding of Henan University of Science and Technology(13480027) to Q. C.the Key Science Foundation of Nanjing Medical University(2015NJMUZD002)+2 种基金the Natural Science Foundation of Higher Education Institutions of Jiangsu Province(16KJB-180020)Natural Science Foundation of Jiangsu Province (BK20171053)National Natural Science Funds of China (81702747) to C.L
文摘Kruppel-like factor 4（Klf4） is a zinc finger transcription factor and plays crucial roles in Xenopus embryogenesis.However, its regulation during embryogenesis is still unclear. Here, we report that Tcf711, a key downstream transducer of the Wnt signaling pathway, could promote Klf4 transcription and stimulate Klf4 promoter activity in early Xenopus embryos. Furthermore, cycloheximide treatment showed a direct effect on Klf4 transcription facilitated by Tcf711. Moreover, the dominant negative form of Tcf711（dnTcf711）, which lacks N-terminus of the β-catenin binding motif, could still activate Klf4 transcription, suggesting that this regulation is Wnt/β-catenin independent.Taken together, our results demonstrate that Tcf711 lies upstream of Klf4 to maintain its expression level during Xenopus embryogenesis.
文摘Salidroside is extensively used as a herbal medicine worldwide, and it has been shown to protect against disruption of endothelial homeostasis and act as an anti-aging agent. The present study aimed to investigate the ameliorative effects of salidroside on homocysteine (Hcy)-induced cell senescence in human umbilical vein endothelial cells (HUVECs) that were mediated via inhibition of Krüppel-like factor 4 (KLF4). An endothelial cell senescence model was induced by Hcy. The cell viability, activities of telomerase and lactate dehydrogenase (LDH), and the level of reactive oxygen species were determined using commercial kits. The expression levels of KLF4, p53 and p21 were determined via western blot analysis, whereas the mRNA expression levels of KLF4 were detected by reverse transcription-quantitative PCR. Small interfering RNA-mediated knockdown of KLF4 was found to reverse Hcy-induced cell senescence. Hcy treatment led to an accelerated cell senescence, as evidenced by decreases in both cell viability and telomerase activity, whereas increases were noted in the leakage of LDH and the level of reactive oxygen species, in addition to an up-regulation of the protein levels of p53 and p21, and up-regulation of KLF4 at both the mRNA and protein level. Treatment with salidroside ameliorated Hcy-induced cell senescence in a dose-dependent manner. Taken together, these results suggested that Hcy may induce cell senescence through upregulation of KLF4, and this may be reversed by treatment with salidroside. Therefore, salidroside was shown to inhibit Hcy-induced cell senescence through KLF4 inhibition.
基金grants from the National Institutes of Health awarded to Yang VW (CA084197)
文摘Aim: Colorectal cancer (CRC) is the third leading cancer-related cause of death due to its propensity to metastasize. Epithelial-mesenchymal transition (EMT) is a multistep process important for invasion and metastasis of CRC. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor highly expressed in differentiated cells of the intestinal epithelium. KLF4 has been shown to play a tumor suppressor role during CRC tumorigenesis - its loss accelerates development and progression of cancer. The present study examined the relationship between KLF4 and markers of EMT in CRC. Methods: Immunofluorescence staining for KLF4 and EMT markers was performed on archived patient samples after colorectal cancer resection and on colonic tissues of mice with colitis-associated cancer. Results: We found that KLF4 expression is lost in tumor sections obtained from CRC patients and in those of mouse colon following azoxymethane and dextran sodium sulfate (AOM/DSS) treatment when compared to their respective normal appearing mucosa. Importantly, in CRC patient tumor sections, we observed a negative correlation between KLF4 levels and mesenchymal markers including TWIST, β-catenin, claudin-1, N-cadherin, and ;vimentin. Similarly, in tumor tissues from AOM/DSS-treated mice, KLF4 levels were negatively correlated with mesenchymal markers including SNAI2, β-catenin, and vimentin and positively correlated with the epithelial marker E-cadherin. Conclusion: These findings suggest that the loss of KLF4 expression is a potentially significant indicator of EMT in CRC.
