Macrophages （Mφ） are prominent components of solid tumors and exhibit distinct phenotypes in different microenvironments. We have recently found that tumors can alter the normal developmental process of Mφ to trig...Macrophages （Mφ） are prominent components of solid tumors and exhibit distinct phenotypes in different microenvironments. We have recently found that tumors can alter the normal developmental process of Mφ to trigger transient activation of monocytes, but the underlying regulatory mechanisms are incompletely understood. Here, we showed that the protein expression of transcription factor C/EBPβ was markedly elevated in tumor-associated Mφ both in vitro and human tumors in situ. The expression of C/EBPβ protein correlated with cytokine production in tumor-activated monocytes. Moreover, we found that C/EBPβ expression was regulated at the post-transcriptional level and correlated with sustained reduction of microRNA-155 （miR-155） in tumor-activated monocytes. Bioinformatic analysis revealed that C/EBPβ is a potential target of miR-155 and luciferase assay confirmed that C/EBPβ translation is suppressed by miR-155 through interaction with the 3＇UTR of C/EBPβ mRNA. Further analysis showed that induction of miR-155 suppressed C/EBPβ protein expression as well as cytokine production in tumor-activated monocytes, an effect which could be mimicked by silencing of C/EBPβ. These results indicate that tumor environment causes a sustained reduction of miR-155 in monocytes/Mφ, which in turn regulates the functional activities of monocytes/Mφ by releasing the translational inhibition of transcription factor C/EBPβ.展开更多
Non-alcoholic fatty liver disease(NAFLD)is associated with mutations in lipopolysaccharide-binding protein(LBP),but the underlying epigenetic mechanisms remain understudied.Herein,LBP^(-/-)rats with NAFLD were establi...Non-alcoholic fatty liver disease(NAFLD)is associated with mutations in lipopolysaccharide-binding protein(LBP),but the underlying epigenetic mechanisms remain understudied.Herein,LBP^(-/-)rats with NAFLD were established and used to conduct integrative targetingactive enhancer histone H3 lysine 27 acetylation(H3K27ac)chromatin immunoprecipitation coupled with high-throughput and transcriptomic sequencing analysis to explore the potential epigenetic pathomechanisms of active enhancers of NAFLD exacerbation upon LBP deficiency.Notably,LBP^(-/-)reduced the inflammatory response but markedly aggravated high-fat diet(HFD)-induced NAFLD in rats,with pronounced alterations in the histone acetylome and regulatory transcriptome.In total,1128 differential enhancer-target genes significantly enriched in cholesterol and fatty acid metabolism were identified between wild-type(WT)and LBP^(-/-)NAFLD rats.Based on integrative analysis,CCAAT/enhancer-binding proteinβ(C/EBPβ)was identified as a pivotal transcription factor(TF)and contributor to dysregulated histone acetylome H3K27ac,and the lipid metabolism gene SCD was identified as a downstream effector exacerbating NAFLD.This study not only broadens our understanding of the essential role of LBP in the pathogenesis of NAFLD from an epigenetics perspective but also identifies key TF C/EBPβand functional gene SCD as potential regulators and therapeutic targets.展开更多
Mammalian asparagine endopeptidase(AEP)is a cysteine protease that cleaves its protein substrates on the Cterminal side of asparagine residues.Converging lines of evidence indicate that AEP may be involved in the path...Mammalian asparagine endopeptidase(AEP)is a cysteine protease that cleaves its protein substrates on the Cterminal side of asparagine residues.Converging lines of evidence indicate that AEP may be involved in the pathogenesis of several neurological diseases,including Alzheimer’s disease,Parkinson’s disease,and frontotemporal dementia.AEP is activated in the aging brain,cleaves amyloid precursor protein(APP)and promotes the production of amyloid-β(Aβ).We renamed AEP to δ-secretase to emphasize its role in APP fragmentation and Aβ production.AEP also cleaves other substrates,such as tau,α-synuclein,SET,and TAR DNA-binding protein 43,generating neurotoxic fragments and disturbing their physiological functions.The activity of δ-secretase is tightly regulated at both the transcriptional and posttranslational levels.Here,we review the recent advances in the role of δ-secretase in neurodegenerative diseases,with a focus on its biochemical properties and the transcriptional and posttranslational regulation of its activity,and discuss the clinical implications of δ-secretase as a diagnostic biomarker and therapeutic target for neurodegenerative diseases.展开更多
C/EBPβ (CCAAT/enhancer-binding protein β) is an important transcription factor involved in cellular proliferation and differentiation. Overexpression of the full-length C/EBPβ protein results in cellular growth arr...C/EBPβ (CCAAT/enhancer-binding protein β) is an important transcription factor involved in cellular proliferation and differentiation. Overexpression of the full-length C/EBPβ protein results in cellular growth arrest and apoptosis. Using a nonviral liposome as carrier, we delivered the full-length C/EBPβ expression plasmid, pCN, into nude mice bearing CW-2 human colon cancer tumors via tail vein. Southern blots revealed that the major organs and tumors were transfected. Experimental gene therapy showed that a strong suppression of tumor growth was observed in the pCN- treated mice, and such suppression was due to the overexpression of C/EBPβ, leading to the increased apoptosis in tumors of pCN-treated mice. No apparent toxic effects of pCN/liposome complex were observed in the animals. Thus, C/EBPβ has tumor suppression effect in vivo and may be used in gene therapy for cancers.展开更多
Alzheimer’s disease(AD)is the most common type of dementia.Almost two-thirds of patients with AD are female.The reason for the higher susceptibility to AD onset in women is unclear.However,hormone changes during the ...Alzheimer’s disease(AD)is the most common type of dementia.Almost two-thirds of patients with AD are female.The reason for the higher susceptibility to AD onset in women is unclear.However,hormone changes during the menopausal transition are known to be associated with AD.Most recently,we reported that follicle-stimulating hormone(FSH)promotes AD pathology and enhances cognitive dysfunctions via activating the CCAAT-enhancer-binding protein(C/EBPβ)/asparagine endopeptidase(AEP)pathway.This review summarizes our current understanding of the crucial role of the C/EBPβ/AEP pathway in driving AD pathogenesis by cleaving multiple critical AD players,including APP and Tau,explaining the roles and the mechanisms of FSH in increasing the susceptibility to AD in postmenopausal females.The FSH-C/EBPβ/AEP pathway may serve as a novel therapeutic target for the treatment of AD.展开更多
Interleukin-5 (IL-5),expressed primarily by type-2 T heler (Th2) cell,plays an essential role in the devel-opment of allergic diseases, such as allergic asthma. Histone acetyltransferase CBP/p300 remodels chromatin by...Interleukin-5 (IL-5),expressed primarily by type-2 T heler (Th2) cell,plays an essential role in the devel-opment of allergic diseases, such as allergic asthma. Histone acetyltransferase CBP/p300 remodels chromatin by acety-lating histones, resulting in open structure of chromatin and active transcription. Adenovirus protein E1A inhibits the activity of CBP/p300. In this study,we analysed the effects of E1A on IL-5 gene promoter/luciferase reporter activity. The results showed that E1A protein inhibited the activity of PMA/ionomycin-stimulated IL-5 gene promoter/luiferase reporter construct. In contrast, overexpression of the CBP/p300-binding defective E1A △2-36 protein did not inhibit IL-5 gene promoter activity. These data demonstrated for the first time that transcriptional coactivator CBP/p300 was involved in the activation of IL-5 gene promoter. E1A protein can modulate CBP/p300 function to activate the transcription of IL-5 gene promoter/luciferase reporter plasmid. Furthermore, in collaboration with transcription factor C/EBP, CBP/p300 activated IL-5 gene pro-moter/luciferase reporter expression. This study provides further insight into the mechanisms of transcriptional regu-lation of IL-5 gene.展开更多
文摘Macrophages （Mφ） are prominent components of solid tumors and exhibit distinct phenotypes in different microenvironments. We have recently found that tumors can alter the normal developmental process of Mφ to trigger transient activation of monocytes, but the underlying regulatory mechanisms are incompletely understood. Here, we showed that the protein expression of transcription factor C/EBPβ was markedly elevated in tumor-associated Mφ both in vitro and human tumors in situ. The expression of C/EBPβ protein correlated with cytokine production in tumor-activated monocytes. Moreover, we found that C/EBPβ expression was regulated at the post-transcriptional level and correlated with sustained reduction of microRNA-155 （miR-155） in tumor-activated monocytes. Bioinformatic analysis revealed that C/EBPβ is a potential target of miR-155 and luciferase assay confirmed that C/EBPβ translation is suppressed by miR-155 through interaction with the 3＇UTR of C/EBPβ mRNA. Further analysis showed that induction of miR-155 suppressed C/EBPβ protein expression as well as cytokine production in tumor-activated monocytes, an effect which could be mimicked by silencing of C/EBPβ. These results indicate that tumor environment causes a sustained reduction of miR-155 in monocytes/Mφ, which in turn regulates the functional activities of monocytes/Mφ by releasing the translational inhibition of transcription factor C/EBPβ.
文摘对实验室前期Solexa结果进行深入挖掘,结合生物信息学分析从不同发育阶段猪皮下脂肪组织差异表达的miRNAs中筛选出高丰度差异极显著的候选miR-191.采用腺病毒过表达miR-191,实时定量PCR、Western blot及双荧光素酶报告基因检测等技术方法,初步研究miR-191对猪前体脂肪细胞分化的影响.结果发现,miR-191随着猪前体脂肪细胞的分化表达量逐渐增加.与对照组相比,过表达miR-191的猪前体脂肪细胞中miR-191转录本显著增加,并引起CCAAT增强子结合蛋白β(C/EBPβ)、PPARγ和aP2的mRNA水平降低,抑制了猪前体脂肪细胞分化.同时,Western blot结果显示,与对照组相比过表达miR-191的猪前体脂肪细胞在48 h C/EBPβ蛋白水平下降了55%.更重要的是,通过TargetScan等算法正向筛选以及MicroInspector反向筛选联合获得miR-191候选靶基因,经双荧光素酶报告基因检测结果证实,miR-191可直接作用于C/EBPβ3′UTR,从而降低萤火虫荧光素酶活性.综上所述,miR-191可能通过抑制脂肪细胞分化早期标志基因C/EBPβ的表达,从而抑制了猪前体脂肪细胞的分化.
基金supported by the National Natural Science Foundation of China(81971875,82300661)Natural Science Foundation of Anhui province(2308085QH246)+3 种基金Natural Science Foundation of the Anhui Higher Education Institutions(KJ2021A0205)Basic and Clinical Cooperative Research Program of Anhui Medical University(2019xkjT002,2019xkjT022,2022xkjT013)Talent Training Program,School of Basic Medical Sciences,Anhui Medical University(2022YPJH102)National College Students Innovation and Entrepreneurship Training Program of China(202210366024)。
文摘Non-alcoholic fatty liver disease(NAFLD)is associated with mutations in lipopolysaccharide-binding protein(LBP),but the underlying epigenetic mechanisms remain understudied.Herein,LBP^(-/-)rats with NAFLD were established and used to conduct integrative targetingactive enhancer histone H3 lysine 27 acetylation(H3K27ac)chromatin immunoprecipitation coupled with high-throughput and transcriptomic sequencing analysis to explore the potential epigenetic pathomechanisms of active enhancers of NAFLD exacerbation upon LBP deficiency.Notably,LBP^(-/-)reduced the inflammatory response but markedly aggravated high-fat diet(HFD)-induced NAFLD in rats,with pronounced alterations in the histone acetylome and regulatory transcriptome.In total,1128 differential enhancer-target genes significantly enriched in cholesterol and fatty acid metabolism were identified between wild-type(WT)and LBP^(-/-)NAFLD rats.Based on integrative analysis,CCAAT/enhancer-binding proteinβ(C/EBPβ)was identified as a pivotal transcription factor(TF)and contributor to dysregulated histone acetylome H3K27ac,and the lipid metabolism gene SCD was identified as a downstream effector exacerbating NAFLD.This study not only broadens our understanding of the essential role of LBP in the pathogenesis of NAFLD from an epigenetics perspective but also identifies key TF C/EBPβand functional gene SCD as potential regulators and therapeutic targets.
基金This work is supported by grants from the National Institute of Health(RF1,AG051538,RO1,NS105982)to K.Yegrants from the National Natural Science Foundation of China(No.81822016,81771382,and 81571249)to Z.Zhang.
文摘Mammalian asparagine endopeptidase(AEP)is a cysteine protease that cleaves its protein substrates on the Cterminal side of asparagine residues.Converging lines of evidence indicate that AEP may be involved in the pathogenesis of several neurological diseases,including Alzheimer’s disease,Parkinson’s disease,and frontotemporal dementia.AEP is activated in the aging brain,cleaves amyloid precursor protein(APP)and promotes the production of amyloid-β(Aβ).We renamed AEP to δ-secretase to emphasize its role in APP fragmentation and Aβ production.AEP also cleaves other substrates,such as tau,α-synuclein,SET,and TAR DNA-binding protein 43,generating neurotoxic fragments and disturbing their physiological functions.The activity of δ-secretase is tightly regulated at both the transcriptional and posttranslational levels.Here,we review the recent advances in the role of δ-secretase in neurodegenerative diseases,with a focus on its biochemical properties and the transcriptional and posttranslational regulation of its activity,and discuss the clinical implications of δ-secretase as a diagnostic biomarker and therapeutic target for neurodegenerative diseases.
文摘C/EBPβ (CCAAT/enhancer-binding protein β) is an important transcription factor involved in cellular proliferation and differentiation. Overexpression of the full-length C/EBPβ protein results in cellular growth arrest and apoptosis. Using a nonviral liposome as carrier, we delivered the full-length C/EBPβ expression plasmid, pCN, into nude mice bearing CW-2 human colon cancer tumors via tail vein. Southern blots revealed that the major organs and tumors were transfected. Experimental gene therapy showed that a strong suppression of tumor growth was observed in the pCN- treated mice, and such suppression was due to the overexpression of C/EBPβ, leading to the increased apoptosis in tumors of pCN-treated mice. No apparent toxic effects of pCN/liposome complex were observed in the animals. Thus, C/EBPβ has tumor suppression effect in vivo and may be used in gene therapy for cancers.
基金supported by start-up funding from Shenzhen Institute of Advanced Technologythe National Natural Science Foundation of China(No.82271446).
文摘Alzheimer’s disease(AD)is the most common type of dementia.Almost two-thirds of patients with AD are female.The reason for the higher susceptibility to AD onset in women is unclear.However,hormone changes during the menopausal transition are known to be associated with AD.Most recently,we reported that follicle-stimulating hormone(FSH)promotes AD pathology and enhances cognitive dysfunctions via activating the CCAAT-enhancer-binding protein(C/EBPβ)/asparagine endopeptidase(AEP)pathway.This review summarizes our current understanding of the crucial role of the C/EBPβ/AEP pathway in driving AD pathogenesis by cleaving multiple critical AD players,including APP and Tau,explaining the roles and the mechanisms of FSH in increasing the susceptibility to AD in postmenopausal females.The FSH-C/EBPβ/AEP pathway may serve as a novel therapeutic target for the treatment of AD.
文摘Interleukin-5 (IL-5),expressed primarily by type-2 T heler (Th2) cell,plays an essential role in the devel-opment of allergic diseases, such as allergic asthma. Histone acetyltransferase CBP/p300 remodels chromatin by acety-lating histones, resulting in open structure of chromatin and active transcription. Adenovirus protein E1A inhibits the activity of CBP/p300. In this study,we analysed the effects of E1A on IL-5 gene promoter/luciferase reporter activity. The results showed that E1A protein inhibited the activity of PMA/ionomycin-stimulated IL-5 gene promoter/luiferase reporter construct. In contrast, overexpression of the CBP/p300-binding defective E1A △2-36 protein did not inhibit IL-5 gene promoter activity. These data demonstrated for the first time that transcriptional coactivator CBP/p300 was involved in the activation of IL-5 gene promoter. E1A protein can modulate CBP/p300 function to activate the transcription of IL-5 gene promoter/luciferase reporter plasmid. Furthermore, in collaboration with transcription factor C/EBP, CBP/p300 activated IL-5 gene pro-moter/luciferase reporter expression. This study provides further insight into the mechanisms of transcriptional regu-lation of IL-5 gene.
