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Syafruddin SE, Mohtar MA, Wan Mohamad Nazarie WF, Low TY. Two Sides of the Same Coin: The Roles of KLF6 in Physiology and Pathophysiology. Biomolecules 2020; 10:biom10101378. [PMID: 32998281 PMCID: PMC7601070 DOI: 10.3390/biom10101378] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 09/26/2020] [Accepted: 09/26/2020] [Indexed: 12/12/2022] Open
Abstract
The Krüppel-like factors (KLFs) family of proteins control several key biological processes that include proliferation, differentiation, metabolism, apoptosis and inflammation. Dysregulation of KLF functions have been shown to disrupt cellular homeostasis and contribute to disease development. KLF6 is a relevant example; a range of functional and expression assays suggested that the dysregulation of KLF6 contributes to the onset of cancer, inflammation-associated diseases as well as cardiovascular diseases. KLF6 expression is either suppressed or elevated depending on the disease, and this is largely due to alternative splicing events producing KLF6 isoforms with specialised functions. Hence, the aim of this review is to discuss the known aspects of KLF6 biology that covers the gene and protein architecture, gene regulation, post-translational modifications and functions of KLF6 in health and diseases. We put special emphasis on the equivocal roles of its full-length and spliced variants. We also deliberate on the therapeutic strategies of KLF6 and its associated signalling pathways. Finally, we provide compelling basic and clinical questions to enhance the knowledge and research on elucidating the roles of KLF6 in physiological and pathophysiological processes.
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Affiliation(s)
- Saiful E. Syafruddin
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur 56000, Malaysia; (M.A.M.); (T.Y.L.)
- Correspondence: ; Tel.: +60-3-9145-9040
| | - M. Aiman Mohtar
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur 56000, Malaysia; (M.A.M.); (T.Y.L.)
| | - Wan Fahmi Wan Mohamad Nazarie
- Biotechnology Programme, Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia;
| | - Teck Yew Low
- UKM Medical Molecular Biology Institute (UMBI), Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur 56000, Malaysia; (M.A.M.); (T.Y.L.)
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MiR-429 regulates blood−spinal cord barrier permeability by targeting Krüppel-like factor 6. Biochem Biophys Res Commun 2020; 525:740-746. [DOI: 10.1016/j.bbrc.2020.02.138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 02/22/2020] [Indexed: 11/17/2022]
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3
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Yang M, Wang Y, Wang Q, Zhou Z, Yu Y, Wei S, Wang S, Qin Q. Characterization of Kruppel-like factor 6 in Epinephelus coioides: The role in viral infection and the transcriptional regulation on Peroxisome proliferator-activated receptor δ. FISH & SHELLFISH IMMUNOLOGY 2020; 99:9-18. [PMID: 32007559 DOI: 10.1016/j.fsi.2020.01.061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 06/10/2023]
Abstract
The Kruppel-like factor 6 (KLF6) is a member of Kruppel-like factor family, which belong to the Zinc finger family of transcription factors that mediates various cellular processes, such as proliferation, differentiation, development, and programmed cell death. Peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors belonging to the nuclear receptor superfamily and they regulate numerous genes through ligand-dependent transcriptional activation and repression. In this study, we focus on the role of KLF6 gene in virus infection and the regulation of KLF6 on PPAR-δ in orange-spotted grouper (Epinephelus coioides). The ORF sequence of EcKLF6 was 846 bp, encoding a polypeptide of 282 amino acids with three conserved Zinc finger (type Cys2-His2) domain in the C-terminal region. Basing on the detection of the mRNA levels of viral genes, western blotting of MCP protein, and morphological CPEs, we found that the overexpression of EcKLF6 suppressed the replication of Singapore grouper iridovirus (SGIV), exerting its antiviral activity against fish virus. Moreover, promoter analysis was performed to investigate whether EcKLF6 was a regulator of EcPPAR-δ. The luciferase reporter assay and real time PCR results indicated a negative regulatory role of EcKLF6 on EcPPAR-δ transcription in grouper. Further experimental analysis shows that the potential EcKLF6 binding sites may locate in the EcPPAR-δ-4-M3 (+133 to +154) and EcPPAR-δ-4-M4 (+354 to +368) region of the EcPPAR-δ promoter. Electrophoretic mobile shift assays (EMSAs) verified that EcKLF6 interacted with the binding site of the EcPPAR-δ-4-M4 promoter region. In addition, we also found that KLF6 promotes inflammatory responses in GS cells. Considering that KLF6 and PPAR-δ play opposite roles in regulating inflammatory responses, we speculated the promoting effect of KLF6 on inflammatory response may be related to its negative regulation on EcPPAR-δ. In conclusion, the present study provides the first evidence of the negative regulation of EcPPAR-δ transcription by EcKLF6 and contributes to a better understanding of the transcriptional mechanisms of EcKLF6 in fish.
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Affiliation(s)
- Min Yang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Yuxin Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Qing Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Zhekai Zhou
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Yepin Yu
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Shina Wei
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Shaowen Wang
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China
| | - Qiwei Qin
- Joint Laboratory of Guangdong Province and Hong Kong Region on Marine Bioresource Conservation and Exploitation, College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266000, China.
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4
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Copy Number Variations of KLF6 Modulate Gene Transcription and Growth Traits in Chinese Datong Yak (Bos Grunniens). Animals (Basel) 2018; 8:ani8090145. [PMID: 30134528 PMCID: PMC6162419 DOI: 10.3390/ani8090145] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 08/06/2018] [Accepted: 08/18/2018] [Indexed: 02/08/2023] Open
Abstract
Copy number variation (CNV) is a significant marker of the genetic and phenotypic diversity among individuals that accounts for complex quantitative traits of phenotype and diseases via modulating gene dosage and disrupting coding regions in the genome. Biochemically, Kruppel-like factor 6 (KLF6) genes plays a significant role in the regulation of cell differentiation and proliferation and muscle development. The aim of this study was to detect the distributions of KLF6 copy number variations (CNVs) in five breeds of domestic yak and to explore their effect on growth traits and gene expression. The data were analyzed by real-time quantitative PCR (qPCR). Our results elucidated that a decreased CNV in the KLF6 gene is more highly associated (p < 0.05) with various growth traits than increased or normal CNVs in six-month-old and five-year-old Datong yak. Nevertheless, negative correlations between the DNA copy number and KLF6 gene expression were observed in the skeletal muscle of adult Datong yak. These results suggest that CNVs of the KLF6 gene could be crucial genomic markers for growth phenotypes of Chinese Datong yak breeds and this finding constitutes the first evidence of the biological role of KLF6 CNVs in Chinese Datong yak breeds.
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Ligand-Dependent Corepressor (LCoR) Is a Rexinoid-Inhibited Peroxisome Proliferator-Activated Receptor γ-Retinoid X Receptor α Coactivator. Mol Cell Biol 2018; 38:MCB.00107-17. [PMID: 29463649 DOI: 10.1128/mcb.00107-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 02/12/2018] [Indexed: 01/11/2023] Open
Abstract
The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ) is an essential regulator of placental development. To gain deeper insights into placental PPARγ signaling, we dissected its regulation of the Muc1 promoter. We find that, unlike prototypic target activation by heterodimeric receptors, which is either stimulated by or refractory to retinoid X receptor (RXR) ligands (rexinoids), the induction of Muc1 by liganded PPARγ requires RXRα but is inhibited by rexinoids. We demonstrate that this inhibition is mediated by the activation function 2 (AF2) domain of RXRα and that Muc1 activation entails altered AF2 structures of both PPARγ and RXRα. This unique regulation of Muc1 reflects specific coactivation of PPARγ-RXRα heterodimers by the transcription cofactor ligand-dependent corepressor (LCoR), corroborated by significant downregulation of Muc1 in Lcor-null placentas. LCoR interacts with PPARγ and RXRα in a synergistic fashion via adjacent noncanonical protein motifs, and the AF2 domain of ligand-bound RXRα inhibits this interaction. We further identify the transcription factor Krüppel-like factor 6 (KLF6) as a critical regulator of placental development and a component of Muc1 regulation in cooperation with PPARγ, RXRα, and LCoR. Combined, these studies reveal new principles and players in nuclear receptor function in general and placental PPARγ signaling in particular.
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Yin L, Guo X, Zhang C, Cai Z, Xu C. In silico analysis of expression data during the early priming stage of liver regeneration after partial hepatectomy in rat. Oncotarget 2018; 9:11794-11804. [PMID: 29545936 PMCID: PMC5837750 DOI: 10.18632/oncotarget.24370] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 12/05/2017] [Indexed: 12/13/2022] Open
Abstract
The priming stage is the first step of liver regeneration (LR). This stage is characterized by the transition from G0 to cell cycle for 4 hours in rat. In this study, individual gene level and gene set level (GSEA) was performed to identify the candidate genes and significantly changed biological processes at 2 h after partial hepatectomy (PH). The leading edge analysis is performed to identify the key genes and iRegulon was employed for transcription factor (TF) analysis. A total of 53 differentially expressed genes were identified using RMA package based on R language at 2 h after PH, including the transcription factor, enzyme and cytokine. As the most important genes in our analysis, Socs3 was selected with a special analysis so as to find the pathways correlate to the expression of it. The changed significantly pathways in LR involved response to stress, ATP metabolism, and regulation of cell cycle mainly. Several transcription factors were identified including Stat5a, Cnot3 and zfp384. Taken together, at the early priming stage of LR in rat, the liver is experiencing some changes including response to stress, activated ATP metabolism and inhibition of cell cycle. Our analysis provided a detailed and comprehensive map for further research of the early priming stage of LR in rat.
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Affiliation(s)
- Li Yin
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation and Henan Engineering Laboratory for Bioengineering and Drug Development, Henan Normal University, Xinxiang 453007, Henan Province, China.,Luohe Medical College, Luohe 462002, Henan Province, China
| | - Xueqiang Guo
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China
| | - Chunyan Zhang
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China
| | - Zhihui Cai
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China.,Luohe Medical College, Luohe 462002, Henan Province, China
| | - Cunshuan Xu
- College of Life Science, Henan Normal University, Xinxiang 453007, Henan Province, China.,State Key Laboratory Cultivation Base for Cell Differentiation Regulation and Henan Engineering Laboratory for Bioengineering and Drug Development, Henan Normal University, Xinxiang 453007, Henan Province, China
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7
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Bialkowska AB, Yang VW, Mallipattu SK. Krüppel-like factors in mammalian stem cells and development. Development 2017; 144:737-754. [PMID: 28246209 DOI: 10.1242/dev.145441] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors that are found in many species. Recent studies have shown that KLFs play a fundamental role in regulating diverse biological processes such as cell proliferation, differentiation, development and regeneration. Of note, several KLFs are also crucial for maintaining pluripotency and, hence, have been linked to reprogramming and regenerative medicine approaches. Here, we review the crucial functions of KLFs in mammalian embryogenesis, stem cell biology and regeneration, as revealed by studies of animal models. We also highlight how KLFs have been implicated in human diseases and outline potential avenues for future research.
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Affiliation(s)
- Agnieszka B Bialkowska
- Division of Gastroenterology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
| | - Vincent W Yang
- Division of Gastroenterology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA.,Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
| | - Sandeep K Mallipattu
- Division of Nephrology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA
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Racca AC, Ridano ME, Bandeira CL, Bevilacqua E, Avvad Portari E, Genti-Raimondi S, Graham CH, Panzetta-Dutari GM. Low oxygen tension induces Krüppel-Like Factor 6 expression in trophoblast cells. Placenta 2016; 45:50-7. [PMID: 27577710 DOI: 10.1016/j.placenta.2016.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 07/06/2016] [Accepted: 07/25/2016] [Indexed: 12/11/2022]
Abstract
The transcription factor Krüppel-Like Factor 6 (KLF6) has important roles in cell differentiation, angiogenesis, apoptosis, and proliferation. Furthermore, there is evidence that KLF6 is required for proper placental development. While oxygen is a critical mediator of trophoblast differentiation and function, the involvement of oxygen in the regulation of KLF6 expression remains unexplored. In the present study we examined the expression of KLF6 in placental tissue from uncomplicated and preeclamptic pregnancies, the latter often characterized by an inadequately perfused placenta. We also determined the effect of hypoxia and the involvement of Hypoxia-Inducible Factor 1α (HIF-1α) on the expression of KLF6 in cultured trophoblast cells and placental tissues. Results revealed that villous, interstitial and endovascular extravillous cytotrophoblasts from placentas from normal and preeclamptic pregnancies express KLF6. In addition, KLF6 immunoreactivity was higher in the placental bed of preeclamptic pregnancies than in those of uncomplicated pregnancies. We demonstrated that hypoxia induced an early and transient increase in KLF6 protein levels in HTR8/SVneo extravillous cytotrophoblast cells and in placental explants. Reoxygenation returned KLF6 protein to basal levels. Moreover, hypoxia-induced up-regulation of KLF6 expression was dependent on HIF-1α as revealed by siRNA knockdown in HTR8/SVneo cells. These results indicate that KLF6 may mediate some of the effects of hypoxia in placental development. The regulation of KLF6 protein levels by oxygen has significant implications for understanding its putative role in diseases affected by tissue hypoxia.
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Affiliation(s)
- A C Racca
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - M E Ridano
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - C L Bandeira
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - E Bevilacqua
- Department of Cell and Developmental Biology, Institute of Biomedical Sciences, University of São Paulo, Brazil
| | - E Avvad Portari
- Department of Pathology at Medical Sciences School, State University of Rio de Janeiro, Brazil
| | - S Genti-Raimondi
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - C H Graham
- Departments of Biomedical and Molecular Sciences and Urology, Queen's University, Kingston, Ontario, Canada
| | - G M Panzetta-Dutari
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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Nian Q, Zhang Z, Wei C, Kuang X, Wang X, Wang L. Gene expression profiling in myelodysplastic syndrome after SPARC overexpression associated with Ara-C. Oncol Rep 2015; 34:2072-82. [PMID: 26238482 DOI: 10.3892/or.2015.4139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 06/30/2015] [Indexed: 12/11/2022] Open
Abstract
Secreted protein acidic and rich in cysteine (SPARC) is involved in many biological processes, including erythropoiesis and cell proliferation. However, the role of SPARC in myelodysplastic syndrome (MDS) remains to be elucidated. Pyrimidine analogue cytosine arabinoside (Ara-C) is among the most effective agents used in the treatment of acute leukemia. The aim of the present study was to determine whether the chemotherapeutic activity of Ara-C was enhanced by the overexpression of SPARC. DNA microarray technology and RNA sequencing were employed to examine differential gene expression in the apoptosis signaling pathway after gene change occurred in cells following drug treatment. The results showed that upregulation of the expression of SPARC induced SKM-1 cell death and inhibited proliferation. Additionally, the apoptotic rate of SPARC overexpression combined with Ara-C increased significantly. Transcription factors CPBP and ZNF333 regulated the 69 genes and long non-coding RNA (lncRNA). Moreover, the mRNA and protein expression of apoptosis-related genes in the DNA microarray results were increased. These results suggest that SPARC expression changes with Ara-C, revealing a possible application in the treatment of MDS.
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Affiliation(s)
- Qing Nian
- Department of Emergency, Children's Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
| | - Zhiqiang Zhang
- Department of Emergency, Children's Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
| | - Chunmei Wei
- Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
| | - Xingyi Kuang
- Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
| | - Xingyong Wang
- Department of Emergency, Children's Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
| | - Li Wang
- Department of Hematology, The First Affiliated Hospital of Chongqing Medical University, Yuzhong, Chongqing 400016, P.R. China
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Human cancer: Is it linked to dysfunctional lipid metabolism? Biochim Biophys Acta Gen Subj 2015; 1850:352-64. [DOI: 10.1016/j.bbagen.2014.11.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/27/2014] [Accepted: 11/03/2014] [Indexed: 11/23/2022]
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Trucco LD, Andreoli V, Núñez NG, Maccioni M, Bocco JL. Krüppel-like factor 6 interferes with cellular transformation induced by the H-ras oncogene. FASEB J 2014; 28:5262-76. [PMID: 25212220 DOI: 10.1096/fj.14-251884] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
KLF6 is a member of the Krüppel-like factor family of transcription factors, with diverse roles in the regulation of cell physiology, including proliferation, signal transduction, and apoptosis. Mutations or down-regulation of KLF6 have been described in several human cancers. In this work, we found that KLF6-knockdown resulted in the formation of transformed foci and allowed the spontaneous conversion of NIH3T3 cells to a tumorigenic state. We further assessed the role of KLF6 in the context of oncogenic Ras. We showed that KLF6 was up-regulated by H-Ras(G12V) expression in a Jun N-terminal kinase (JNK)-dependent manner, correlated with enhanced klf6 promoter activity. We found that ectopic KLF6 expression induced a G1-phase cell cycle arrest, thereby decreasing the cell proliferation rate. In addition, constitutive KLF6 expression impaired H-Ras(G12V)-mediated loss of density-dependent growth inhibition and anchorage-independent growth. Moreover, growth of H-Ras(G12V)-driven tumors was reduced in mice challenged with cells stably expressing KLF6. KLF6 expression correlated with the up-regulation of p21, whereas neither p53 induction nor apoptotic cell death was detected. Further, p21 knockdown impaired KLF6-induced cell cycle arrest. These findings provide novel evidence highlighting KLF6 function in response to malignant transformation, suggesting the relevance of KLF6 in controlling cell proliferation and hindering tumorigenesis.
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Affiliation(s)
- Lucas Daniel Trucco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Verónica Andreoli
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Nicolás Gonzalo Núñez
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Mariana Maccioni
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - José Luis Bocco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Nagata K, Hama I, Kiryu-Seo S, Kiyama H. microRNA-124 is down regulated in nerve-injured motor neurons and it potentially targets mRNAs for KLF6 and STAT3. Neuroscience 2013; 256:426-32. [PMID: 24184980 DOI: 10.1016/j.neuroscience.2013.10.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/23/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
Abstract
MicroRNA (miRNA) is a small non-coding RNA that regulates gene expression by degrading target mRNAs or inhibiting translation. Although many miRNAs play important roles in various conditions, it is unclear whether miRNAs are involved in motor nerve regeneration. In this study, we identified the possible implication of miR-124 in nerve regeneration using a mouse hypoglossal nerve injury model. The significant down-regulation of miR-124 was observed in injured hypoglossal motor neurons after nerve injury, and this transient down-regulation showed a clear inverse correlation with the up-regulation of KLF6 and STAT3, known as axon elongation factor and regeneration-associated molecules, respectively. Furthermore, the luciferase assay and in vitro gain of function methods supported that both genes could be potent targets of miR-124. These results suggest that injury-induced repression of miR-124 may be implicated in the regulation of expression of several injury-associated transcription factors, which are crucial for appropriate nerve regeneration.
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Affiliation(s)
- K Nagata
- Laboratory for Proteolytic Neuroscience, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - I Hama
- Department of Anatomy and Neurobiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan
| | - S Kiryu-Seo
- Department of Anatomy and Neurobiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan; Department of Functional Anatomy & Neuroscience, Graduate School of Medicine, 65 Tsurumaicho, Showa-ku, Nagoya 466-8550, Japan; CREST, JST, Nagoya University, Graduate School of Medicine, 65 Tsurumaicho, Showa-ku, Nagoya 466-8550, Japan
| | - H Kiyama
- Department of Anatomy and Neurobiology, Osaka City University Graduate School of Medicine, 1-4-3 Asahimachi, Abeno-ku, Osaka 545-8585, Japan; Department of Functional Anatomy & Neuroscience, Graduate School of Medicine, 65 Tsurumaicho, Showa-ku, Nagoya 466-8550, Japan; CREST, JST, Nagoya University, Graduate School of Medicine, 65 Tsurumaicho, Showa-ku, Nagoya 466-8550, Japan.
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Xu K, Zhou Y, Qiu W, Liu X, Xia M, Liu L, Liu X, Zhao D, Wang Y. Activating transcription factor 3 (ATF3) promotes sublytic C5b-9-induced glomerular mesangial cells apoptosis through up-regulation of Gadd45α and KLF6 gene expression. Immunobiology 2011; 216:871-81. [DOI: 10.1016/j.imbio.2011.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 01/13/2011] [Accepted: 02/15/2011] [Indexed: 01/08/2023]
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14
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Krüppel-like factor 6 expression changes during trophoblast syncytialization and transactivates ßhCG and PSG placental genes. PLoS One 2011; 6:e22438. [PMID: 21799854 PMCID: PMC3142166 DOI: 10.1371/journal.pone.0022438] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 06/27/2011] [Indexed: 11/19/2022] Open
Abstract
Background Krüppel-like factor-6 (KLF6) is a widely expressed member of the Sp1/KLF family of transcriptional regulators involved in differentiation, cell cycle control and proliferation in several cell systems. Even though the highest expression level of KLF6 has been detected in human and mice placenta, its function in trophoblast physiology is still unknown. Methodology/Principal Findings Herein, we explored KLF6 expression and sub-cellular distribution in human trophoblast cells differentiating into the syncytial pathway, and its role in the regulation of genes associated with placental development and pregnancy maintenance. Confocal immunofluorescence microscopy demonstrated that KLF6 is expressed throughout human cytotrophoblast differentiation showing no evident modifications in its nuclear and cytoplasmic localization pattern. KLF6 transcript and protein peaked early during the syncytialization process as determined by qRT-PCR and western blot assays. Overexpression of KLF6 in trophoblast-derived JEG-3 cells showed a preferential nuclear signal correlating with enhanced expression of human β-chorionic gonadotropin (βhCG) and pregnancy-specific glycoprotein (PSG) genes. Moreover, KLF6 transactivated βhCG5, PSG5 and PSG3 gene promoters. Deletion of KLF6 Zn-finger DNA binding domain or mutation of the consensus KLF6 binding site abolished transactivation of the PSG5 promoter. Conclusions/Significance Results are consistent with KLF6 playing a role as transcriptional regulator of relevant genes for placental differentiation and physiology such as βhCG and PSG, in agreement with an early and transient increase of KLF6 expression during trophoblast syncytialization.
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Andreoli V, Gehrau RC, Bocco JL. Biology of Krüppel-like factor 6 transcriptional regulator in cell life and death. IUBMB Life 2011; 62:896-905. [PMID: 21154818 DOI: 10.1002/iub.396] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An essential role for the Krüppel-like transcription factor family has been determined in the regulation of remarkable processes including cell proliferation, differentiation, signal transduction, oncogenesis, and cell death. A member of this group, Krüppel-like factor 6 (KLF6), identified on the basis of its ability to regulate a group of genes belonging to the carcinoembryonic antigen gene family, has been involved in human carcinogenesis. Early studies proposed a tumor suppressor function for KLF6 because of its ability to reduce cell proliferation through several biochemical mechanisms including regulation of cell cycle components, oncogene products, and apoptosis. Mutations within the klf6 gene, decreased expression and/or loss-of-heterozygosity were associated with the development of different human malignancies, and, hence, further supporting the tumor suppressor function of KLF6. This view has been challenged by other studies in distinct types of human cancers describing infrequent genetic alterations of klf6 gene or even enhanced expression in some tumors. The scenario about KLF6 function became still more complex as the description of oncogenic KLF6 splice variant 1 (SV1) with dominant negative activity against the wild type KLF6 (wtKLF6) protein. Additionally, increased evidence is suggesting that KLF6 is a bonafide target of several signaling cascades, which ultimate regulatory effect on this protein could drive decisions of cell life and death, facing the dilemma about how wtKLF6 could be involved in both processes. These apparently conflicting situations, emerged by apparently opposite effects mediated by wtKLF6, may be related, at least in part, to the biological cross-talk with the c-Jun oncoprotein. Depending on the stimulus received by the cell, wtKLF6 interaction with c-Jun determines different cell outcomes such as proliferation control or apoptosis. Thus, KLF6 responsiveness represents a kind of cell warning signal on receiving different stimuli, including oncogenic activation and microbial infections, orchestrating the implementation of proliferation and apoptotic programs.
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Affiliation(s)
- Verónica Andreoli
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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16
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Tchirkov A, Sapin V, Marceau G, Chautard E, Narla G, Veronese L, Friedman S, Khalil T, Vago P, Kemeny JL, Verrelle P. Increased expression of the oncogenic KLF6-SV1 transcript in human glioblastoma. Clin Chem Lab Med 2010; 48:1167-70. [PMID: 20545576 DOI: 10.1515/cclm.2010.219] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Gliomas constitute the vast majority of primary central nervous system tumors in adults. Glioblastoma multiforme (GBM) is the most aggressive form of these primary brain tumors. There is a need to define diagnostic and prognostic markers that may help to distinguish GBM from non-GBM tumors. The Krüppel-like factor 6 (KLF6) gene has recently emerged as a promising candidate. The goal of our study was to determine if there is a link between KLF6 splice variants expression and different grades of gliomas. METHODS Fifty-three primary gliomas tumor samples were analyzed using quantitative real-time PCR for the total KLF6, wild-type and alternatively spliced (SV1) KLF6 mRNA. RESULTS Compared to the non-GBM group, the GBM group had a 2.2-fold increase in the mean level of total KLF6 mRNA expression. GBM showed a 2.1-fold increase in the KLF6 splicing ratio. In addition, KLF6-SV1 mRNA expression levels were also 2.2-fold higher in the GBM group, suggesting that the increase in the KLF6 splicing ratio was due to increased expression of the KLF6-SV1 oncogenic splice variant. CONCLUSIONS Our study demonstrates that quantification of total and spliced forms of KLF6 may provide a new and useful supplementary molecular tool for grading glioma.
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Affiliation(s)
- Andrei Tchirkov
- University Clermont 1, EA 3846, School of Medicine, Clermont-Ferrand, France
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17
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Abstract
The Krüppel-like factor (KLF) family of transcription factors regulates diverse biological processes that include proliferation, differentiation, growth, development, survival, and responses to external stress. Seventeen mammalian KLFs have been identified, and numerous studies have been published that describe their basic biology and contribution to human diseases. KLF proteins have received much attention because of their involvement in the development and homeostasis of numerous organ systems. KLFs are critical regulators of physiological systems that include the cardiovascular, digestive, respiratory, hematological, and immune systems and are involved in disorders such as obesity, cardiovascular disease, cancer, and inflammatory conditions. Furthermore, KLFs play an important role in reprogramming somatic cells into induced pluripotent stem (iPS) cells and maintaining the pluripotent state of embryonic stem cells. As research on KLF proteins progresses, additional KLF functions and associations with disease are likely to be discovered. Here, we review the current knowledge of KLF proteins and describe common attributes of their biochemical and physiological functions and their pathophysiological roles.
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Affiliation(s)
- Beth B McConnell
- Departments of Medicine and of Hematology and Medical Oncology, Emory University School of Medicine,Atlanta, Georgia 30322, USA
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18
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Gehrau RC, D'Astolfo DS, Dumur CI, Bocco JL, Koritschoner NP. Nuclear expression of KLF6 tumor suppressor factor is highly associated with overexpression of ERBB2 oncoprotein in ductal breast carcinomas. PLoS One 2010; 5:e8929. [PMID: 20126619 PMCID: PMC2812494 DOI: 10.1371/journal.pone.0008929] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Accepted: 01/08/2010] [Indexed: 11/19/2022] Open
Abstract
Background Krüppel-like factor 6 (KLF6) is an evolutionarily conserved and ubiquitously expressed protein that belongs to the mammalian Sp1/KLF family of transcriptional regulators. Though KLF6 is a transcription factor and harbors a nuclear localization signal it is not systematically located in the nucleus but it was detected in the cytoplasm of several tissues and cell lines. Hence, it is still not fully settled whether the tumor suppressor function of KLF6 is directly associated with its ability to regulate target genes. Methodology/Principal Findings In this study we analyzed KLF6 expression and sub-cellular distribution by immunohistochemistry in several normal and tumor tissues in a microarray format representing fifteen human organs. Results indicate that while both nuclear and cytoplasmic distribution of KLF6 is detected in normal breast tissues, breast carcinomas express KLF6 mainly detected in the cytoplasm. Expression of KLF6 was further analyzed in breast cancer tissues overexpressing ERBB2 oncoprotein, which is associated with poor disease prognosis and patient's survival. The analysis of 48 ductal carcinomas revealed a significant population expressing KLF6 predominantly in the nuclear compartment (X2p = 0.005; Fisher p = 0.003). Moreover, this expression pattern correlates directly with early stage and small ductal breast tumors and linked to metastatic events in lymph nodes. Conclusions/Significance Data are consistent with a preferential localization of KLF6 in the nuclear compartment of early stage and small HER2-ERBB2 overexpressing ductal breast tumor cells, also presenting lymph node metastatic events. Thus, KLF6 tumor suppressor could represent a new molecular marker candidate for tumor prognosis and/or a potential target for therapy strategies.
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Affiliation(s)
- Ricardo C. Gehrau
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Diego S. D'Astolfo
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC-CONICET), Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Catherine I. Dumur
- Department of Pathology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - José L. Bocco
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
- * E-mail:
| | - Nicolás P. Koritschoner
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI-CONICET), Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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Jeong KH, Kim SK, Kim SY, Cho KO. Immunohistochemical localization of Krüppel-like factor 6 in the mouse forebrain. Neurosci Lett 2009; 453:16-20. [PMID: 19429007 DOI: 10.1016/j.neulet.2009.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 01/31/2009] [Accepted: 02/02/2009] [Indexed: 10/21/2022]
Abstract
Krüppel-like factor 6 (KLF6) is a transcriptional regulator that shows widespread distribution in the peripheral organs of the body. However, it remains uncertain where KLF6 is expressed in the adult forebrain under physiological conditions. Therefore, the present study investigated the spatial patterns of KLF6 expression and identified cell types expressing KLF6 in the forebrain. KLF6 immunoreactivity was widely seen throughout the forebrain including the olfactory bulb, cerebral cortex, hippocampus, septum, amygdala, basal ganglia, thalamus, and hypothalamus. Moreover, KLF6-positive cells were also detected in the radial migratory stream (RMS) and subventricular zone. Immunofluorescent double-labeling revealed that KLF6-immunoreactive cells were co-localized with neuronal nuclei or platelet endothelial cell adhesion molecule-1, a mature neuronal and endothelial marker, respectively, in most forebrain regions. In the RMS, KLF6 was co-expressed with polysialic neural cell adhesion molecule, a marker of neuronal progenitor cells. This is the first report showing that KLF6 protein is expressed in various regions of the adult forebrain and KLF6-positive cells manifest neuronal or endothelial phenotypes under physiological conditions.
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Affiliation(s)
- Kyoung Hoon Jeong
- Department of Pharmacology, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, 137-701 Seoul, Republic of Korea
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20
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Bentov I, Narla G, Schayek H, Akita K, Plymate SR, LeRoith D, Friedman SL, Werner H. Insulin-like growth factor-i regulates Kruppel-like factor-6 gene expression in a p53-dependent manner. Endocrinology 2008; 149:1890-7. [PMID: 18174288 DOI: 10.1210/en.2007-0844] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
High-circulating IGF-I concentrations are associated with an increased risk for breast, prostate, and colorectal cancer. Krüppel-like factor-6 (KLF6) is a zinc finger tumor suppressor inactivated in prostate and other types of cancer. We have previously demonstrated that KLF6 is a potent transactivator of the IGF-I receptor promoter. The aim of the present study was to examine the potential regulation of KLF6 gene expression by IGF-I. The human colon cancer cell lines HCT116 +/+ and -/- (with normal and disrupted p53, respectively) were treated with IGF-I. Western blots, quantitative RT-PCR, and transfection assays were used to evaluate the effect of IGF-I on KLF-6 production. Signaling pathway inhibitors were used to identify the mechanisms responsible for regulation of KLF6 expression. Small interfering RNA against p53 and KLF6 was used to assess the role of p53 in regulation of KLF6 expression by IGF-I and to evaluate KLF6 involvement in cell cycle control. Results obtained showed that IGF-I stimulated KLF-6 transcription in cells with normal, but not disrupted, p53, suggesting that KLF6 is a downstream target for IGF-I action. Stimulation of KLF6 expression by IGF-I in a p53-dependent manner may constitute a novel mechanism of action of IGF-I, with implications in normal cell cycle progression and cancer biology.
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Affiliation(s)
- Itay Bentov
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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21
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Silencing of the transcription factor KLF6 by siRNA leads to cell cycle arrest and sensitizes cells to apoptosis induced by DNA damage. Cell Death Differ 2008; 15:613-6. [DOI: 10.1038/sj.cdd.4402299] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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22
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Blanchon L, Nores R, Gallot D, Marceau G, Borel V, Yang VW, Bocco JL, Lémery D, Panzetta-Dutari G, Sapin V. Activation of the human pregnancy-specific glycoprotein PSG-5 promoter by KLF4 and Sp1. Biochem Biophys Res Commun 2006; 343:745-53. [PMID: 16563348 DOI: 10.1016/j.bbrc.2006.03.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 03/03/2006] [Indexed: 11/17/2022]
Abstract
Pregnancy-specific glycoproteins (PSGs) are major placental proteins thought to be essential for the maintenance of gestation. Little is known about the regulation of expression of the 11 genes encoding these proteins. It was previously demonstrated that Krüppel-like factor 6 (KLF6) and specific-protein 1 (Sp1) bind to conserved sequence within the PSG-5 gene promoter. Informatics analysis revealed the presence of one potential binding site for Krüppel-like factor 4 (KLF4), in the PSG-5 promoter, suggesting a potential transcriptional regulator role for KLF4. Using gene promoter-reporter transfections and X-ChIP assays, we demonstrated that KLF4 is an activator of the PSG-5 promoter by binding to a KLF consensus like binding which includes the Core Promoter Element region (-147/-140). Furthermore, we used previous data showing the binding of Sp1 transcription factor to a GT-box (-443/-437) and co-transfection assays with KLF4 and Sp1 to demonstrate the strong synergic activity of these two factors on the PSG-5 promoter.
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Affiliation(s)
- Loïc Blanchon
- INSERM U.384, Laboratoire de Biochimie, Faculté de Médecine, F-63000 Clermont-Ferrand, France
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23
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Tarabishi R, Zahedi K, Mishra J, Ma Q, Kelly C, Tehrani K, Devarajan P. Induction of Zf9 in the kidney following early ischemia/reperfusion. Kidney Int 2005; 68:1511-9. [PMID: 16164628 DOI: 10.1111/j.1523-1755.2005.00563.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND An improved understanding of the early cell injury mechanisms is critical for effective therapy of acute renal failure (ARF). METHODS We utilized cDNA microarrays to identify renal genes that are induced very early after renal ischemia in a mouse model, whose protein products might provide novel information regarding the pathogenesis of ARF. The findings were confirmed by downstream mRNA and protein expression studies, as well as knockdown analysis with antisense primers. RESULTS The maximally induced gene (21-fold at 3 hours of reflow) was Zf9, a Kruppel-like transcription factor involved in the regulation of transforming growth factor-beta1 (TGF-beta1). The rapid induction of Zf9 mRNA was confirmed by Northern analysis (14.5-fold at 3 hours of reflow) and that of Zf9 protein by Western analysis (10.5-fold at 3 hours of reflow). Zf9 protein was induced in both proximal and distal tubule cells in a cytoplasmic as well as nuclear distribution. TGF-beta1 protein was also up-regulated in a pattern parallel to that of Zf9. In cultured human proximal tubule cells, induction of ischemia by partial adenosine triphosphate (ATP) depletion resulted in a rapid up-regulation of both Zf9 and of TGF-beta1 proteins. Antisense oligonucleotides to Zf9 markedly blunted the induction of Zf9 and TGF-beta1, and significantly inhibited the apoptotic response to ATP depletion. CONCLUSION Induction of Zf9 and its transactivating factor TGF-beta1 may play a critical and hitherto unrecognized role in the early apoptotic response to ischemic renal injury.
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Affiliation(s)
- Ridwan Tarabishi
- Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, Ohio 45229, USA
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24
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Gehrau RC, D'Astolfo DS, Prieto C, Bocco JL, Koritschoner NP. Genomic organization and functional analysis of the gene encoding the Krüppel-like transcription factor KLF6. ACTA ACUST UNITED AC 2005; 1730:137-46. [PMID: 16054710 DOI: 10.1016/j.bbaexp.2005.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2004] [Revised: 06/08/2005] [Accepted: 06/10/2005] [Indexed: 12/31/2022]
Abstract
The Krüppel-like transcription Factor 6 (KLF6) is regulated during cell proliferation and differentiation events like mammalian development and tissue regeneration, while its aberrant expression is associated with tumor formation. To investigate KLF6 transcriptional control, the genomic organization of human KLF6 together with its cis-regulatory region was analyzed. A high sequence homology of KLF6 regulatory regions was found in mammals, which in turn predicts a high degree of evolutionary conserved transcriptional mechanisms. A transcription start site was identified at the first nucleotide downstream of a potential initiator element. Also, the role of KLF6 regulatory regions was determined by transfection experiments. A minimal promoter region lacking a TATA-box yet containing an Initiator was identified and found to be active in all cells analyzed. In addition, two strong activating sequences were located between positions -407/-344 and -307/-207, where the latter contained Sp1 and CAAT-box sites. Furthermore, ectopic expression of Sp1 increased the transcriptional activity of the KLF6 promoter. In conclusion, our data revealed that KLF6 gene transcription is under control of a TATA-box independent initiation mechanism together with an evolutionary conserved array of positive cis-acting elements.
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Affiliation(s)
- Ricardo C Gehrau
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000-Córdoba, Argentina
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25
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Marceau G, Volle DH, Gallot D, Mangelsdorf DJ, Sapin V, Lobaccaro JMA. Placental expression of the nuclear receptors for oxysterols LXR? and LXR? during mouse and human development. ACTA ACUST UNITED AC 2005; 283:175-81. [PMID: 15674823 DOI: 10.1002/ar.a.20157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Ontogenesis and localization expression of genes encoding for the nuclear receptors for oxysterols (lxralpha and lxrbeta) were investigated in human and mouse placenta during gestation. Both mRNAs were detectable in the placentation throughout the gestation (from 7 days postcoitum and 6th week of gestation in mouse and human, respectively) by Northern blots or RT-PCR experiments. Lxralpha showed a higher accumulation in the mouse yolk sac. In situ hybridization pointed a specific expression of lxralpha in the human amniotic membranes.
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26
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Slavin DA, Koritschoner NP, Prieto CC, López-Díaz FJ, Chatton B, Bocco JL. A new role for the Kruppel-like transcription factor KLF6 as an inhibitor of c-Jun proto-oncoprotein function. Oncogene 2004; 23:8196-205. [PMID: 15378003 DOI: 10.1038/sj.onc.1208020] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Kruppel-like transcription factors (KLFs) represent one of the most diverse set of regulators in vertebrate organisms. KLF family members are involved in cell proliferation and differentiation control in normal as well as in pathological situations. Here, we demonstrate that KLF6 behaves as a functional antagonist of the c-Jun proto-oncoprotein. Thus, KLF6 overexpression downregulated c-Jun-dependent transcription and a physical interaction between c-Jun and KLF6 was detected. Moreover, cell proliferation induced by c-Jun was significantly decreased by KLF6. The inhibition of c-Jun functions correlates directly with c-Jun protein degradation induced by KLF6. We also show that all KLF6 effects on c-Jun were largely dependent on phorbol ester (TPA/ionomycin) extracellular stimulation, which enhanced KLF6 nuclear translocation and transcriptional activity and modified its phosphorylation status. Our data are consistent with a novel mechanism of KLF6's role as an inhibitor of cell proliferation by counteracting the function of the c-Jun proto-oncoprotein involving enhanced c-Jun degradation by the proteasome-dependent pathway, and further reinforces KLF6 as a potential tumor suppressor gene product.
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Affiliation(s)
- Daniela A Slavin
- Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI - CONICET). Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
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27
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Asano N, Kondoh M, Ebihara C, Fujii M, Nakanishi T, Soares MJ, Nakashima E, Tanaka K, Sato M, Watanabe Y. Expression profiles of zinc transporters in rodent placental models. Toxicol Lett 2004; 154:45-53. [PMID: 15475177 DOI: 10.1016/j.toxlet.2004.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 07/02/2004] [Accepted: 07/02/2004] [Indexed: 12/01/2022]
Abstract
Zinc is a vital metal that is a structural and functional component of many proteins. The precise mechanism of zinc transport in the placenta remains unclear. In this study, we investigated the expression of zinc transporters (ZnTs) in the mouse placenta and in two rat trophoblast cell lines, TR-TBT cells, which are syncytiotrophoblast cells of the labyrinth zone, and Rcho-1 cells, which retain trophoblast cell features and differentiate into trophoblast giant cells of the junctional zone. All of the ZnTs that have been identified in mice (ZnT1-7) were detected in the mouse placenta by RT-PCR. The expression profiles of ZnTs in the placenta during pregnancy were different. The mRNA levels of ZnTs, with the exception of ZnT7, did not change during pregnancy. The ZnT7 mRNA level in placenta was elevated during pregnancy. In TR-TBT cells, ZnT1, ZnT3 and ZnT4 were detected by RT-PCR analysis. In Rcho-1 cells, all of the ZnTs that have been identified in rats (ZnT1-4) were detected by RT-PCR analysis. There were no differences between the mRNA expression levels of ZnT family members in undifferentiated Rcho-1 cells and differentiated Rcho-1 cells. This is the first report of expression profiles of ZnTs during differentiation of the placenta in the mouse placenta and rat placental cell models.
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Affiliation(s)
- Nagayoshi Asano
- Department of Biopharmaceutics and Pharmaceutics, Showa Pharmaceutical University, Tokyo 194-8543, Japan
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28
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Nores R, Blanchon L, López-Díaz F, Bocco JL, Patrito LC, Sapin V, Panzetta-Dutari GM. Transcriptional control of the human pregnancy-specific glycoprotein 5 gene is dependent on two GT-boxes recognized by the ubiquitous specificity protein 1 (Sp1) transcription factor. Placenta 2004; 25:9-19. [PMID: 15013634 DOI: 10.1016/s0143-4004(03)00213-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2003] [Revised: 07/03/2003] [Accepted: 07/29/2003] [Indexed: 11/28/2022]
Abstract
Pregnancy-specific glycoprotein 5 gene (PSG-5) belongs to the human pregnancy-specific glycoprotein family, encoded by eleven highly similar and transcriptionally active genes. High levels of PSG biosynthesis are restricted to the placenta syncytiotrophoblast and are essential for the maintenance of normal gestation in mammalian species. We have investigated here the nature of the transcription factors that recognize the FP1 (-455/-433) and the CPE (-147/-140) regulatory sequences that significantly contribute to basal PSG-5 promoter activity. Both elements bear a similar GT-box motif; and DNA-protein complex formation, as well as promoter activity, is largely dependent on the integrity of these GT-box sequences. Gel shift, super gel shift and UV-crosslinking experiments clearly demonstrate that the ubiquitous specificity protein 1 (Sp1) is the major transcription factor involved in complex formation with both cis-acting elements in normal term placenta tissue and in PSG-non-expressing COS-7 cells. Furthermore, transfection experiments indicate that Sp1 activates PSG-5 promoter constructs. In addition, we show that Sp1 is indeed co-expressed with PSG genes in the syncytiotrophoblast cells, stressing its potential role in the in vivo regulation of PSG expression.
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Affiliation(s)
- R Nores
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Haya de la Torre, Ciudad Universitaria, 5000 Córdoba, Argentina
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29
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Warke VG, Nambiar MP, Krishnan S, Tenbrock K, Geller DA, Koritschoner NP, Atkins JL, Farber DL, Tsokos GC. Transcriptional activation of the human inducible nitric-oxide synthase promoter by Kruppel-like factor 6. J Biol Chem 2003; 278:14812-9. [PMID: 12590140 DOI: 10.1074/jbc.m300787200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nitric oxide is a ubiquitous free radical that plays a key role in a broad spectrum of signaling pathways in physiological and pathophysiological processes. We have explored the transcriptional regulation of inducible nitric-oxide synthase (iNOS) by Krüppel-like factor 6 (KLF6), an Sp1-like zinc finger transcription factor. Study of serial deletion constructs of the iNOS promoter revealed that the proximal 0.63-kb region can support a 3-6-fold reporter activity similar to that of the full-length 16-kb promoter. Within the 0.63-kb region, we identified two CACCC sites (-164 to -168 and -261 to -265) that bound KLF6 in both electrophoretic mobility shift and chromatin immunoprecipitation assays. Mutation of both these sites abrogated the KLF6-induced enhancement of the 0.63-kb iNOS promoter activity. The binding of KLF6 to the iNOS promoter was significantly increased in Jurkat cells, primary T lymphocytes, and COS-7 cells subjected to NaCN-induced hypoxia, heat shock, serum starvation, and phorbol 12-myristate 13-acetate/ ionophore stimulation. Furthermore, in KLF6-transfected and NaCN-treated COS-7 cells, there was a 3-4-fold increase in the expression of the endogenous iNOS mRNA and protein that correlated with increased production of nitric oxide. These findings indicate that KLF6 is a potential transactivator of the human iNOS promoter in diverse pathophysiological conditions.
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Affiliation(s)
- Vishal G Warke
- Department of Cellular Injury, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA
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30
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Blanchon L, Bocco JL, Gallot D, Gachon AM, Lémery D, Déchelotte P, Dastugue B, Sapin V. Co-localization of KLF6 and KLF4 with pregnancy-specific glycoproteins during human placenta development. Mech Dev 2001; 105:185-9. [PMID: 11429296 DOI: 10.1016/s0925-4773(01)00391-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Pregnancy-specific glycoproteins (PSGs) are major placental proteins essential for the maintenance of normal gestation. However, little is known about their gene expression regulation during placentation. It was previously demonstrated that the human core promoter binding protein recently renamed Krüppel-like factor (KLF) 6 binds to a highly conserved sequence within the PSG promoters and is mainly expressed in human term placenta. Here, we determined the expression pattern of the 13 other KLFs during human placental development. We demonstrate that eight KLFs exhibit specific expression patterns in human placental tissues and membranes, in favor of a functional cooperation of specific KLFs during placentation. In addition, we demonstrate that KLF6, KLF4 and PSG proteins are co-expressed in same cell types of placental villi and membranes. This experimental evidence further strengthens the potential cross talk of both transcription factors for PSG gene regulation in vivo.
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Affiliation(s)
- L Blanchon
- INSERM U.384, Faculté de Médecine, 63000, Clermont-Ferrand, France
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31
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Warke VG, Krishnan S, Nambiar MP, Farber DL, Tsokos GC, Wong HK. Identification of differentially expressed genes in human memory (CD45RO+) CD4+ T lymphocytes. Immunol Invest 2001; 30:87-101. [PMID: 11465674 DOI: 10.1081/imm-100104018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The precise nature and development of the memory (CD45RO+) CD4+ T lymphocytes remain unknown. In this study, we analyzed differential gene expression of human memory CD4+ T lymphocytes in relation to their naive counterparts. A suppression subtractive hybridization technique was used to isolate and clone differentially expressed genes in the memory subset with respect to the naive subset. We screened approximately 300 clones by dot blot analysis and sequenced 23 differentially expressed clones. GenBank sequence homology search showed that these clones included genes for transcription factors, enzymes and immunomodulatory molecules. Differential expression of a subset of these genes was further confirmed by RT-PCR and densitometric analysis revealed that they were expressed five to eightfold more in memory than naive CD4+ T lymphocytes. Collectively, these results suggest that multiple genes with different functions contribute to the development of immunological memory in human T lymphocytes.
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Affiliation(s)
- V G Warke
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park 20742, USA
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