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Liu Z, Li C, Chen Q, Bai C, Wu G, Fu C, He T, Shen M, Feng C, Liu H. Follicular fluid meiosis-activating sterol prevents porcine ovarian granulosa cells from hypoxia-induced apoptosis via inhibiting STAT4 expression. J Anim Sci 2024; 102:skae125. [PMID: 38713167 PMCID: PMC11245709 DOI: 10.1093/jas/skae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Accepted: 05/04/2024] [Indexed: 05/08/2024] Open
Abstract
Follicular fluid meiosis-activating sterol (FF-MAS) is a small molecule compound found in FF, named for its ability to induce oocyte resumption of meiosis. Granulosa cells (GCs) within the follicle are typically located in a hypoxic environment under physiologic conditions due to limited vascular distribution. Previous research suggests that hypoxia-induced cell cycle arrest and apoptosis in GCs may be crucial triggering factors in porcine follicular atresia. However, the impact of FF-MAS on GCs within follicles has not been explored so far. In this study, we uncovered a novel role of FF-MAS in facilitating GC survival under hypoxic conditions by inhibiting STAT4 expression. We found that STAT4 expression was upregulated in porcine GCs exposed to 1% O2. Both gain and loss of function assays confirmed that STAT4 was required for cell apoptosis under hypoxia conditions, and that the GC apoptosis caused by hypoxia was markedly attenuated following FF-MAS treatment through inhibition of STAT4 expression. Correlation analysis in vivo revealed that GC apoptosis was associated with increased STAT4 expression, while the FF-MAS content in follicular fluid was negatively correlated with STAT4 mRNA levels and cell apoptosis. These findings elucidate a novel role of FF-MAS-mediated protection of GCs by inhibiting STAT4 expression under hypoxia, which might contribute to the mechanistic understanding of follicular development.
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Affiliation(s)
- Zhaojun Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chengyu Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Qianqian Chen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chenyu Bai
- Beijing 101 High School, Beijing, 100084, China
| | - Gang Wu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chen Fu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Tong He
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Ming Shen
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Chungang Feng
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
| | - Honglin Liu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China
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DasGupta M, Kumaresan A, Saraf KK, Paul N, Sajeevkumar T, Karthikkeyan G, Prasad TSK, Modi PK, Ramesha K, Manimaran A, Jeyakumar S. Deciphering metabolomic alterations in seminal plasma of crossbred (Bos taurus X Bos indicus) bulls through comparative deep metabolomic analysis. Andrologia 2021; 54:e14253. [PMID: 34549825 DOI: 10.1111/and.14253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 08/14/2021] [Accepted: 09/13/2021] [Indexed: 12/31/2022] Open
Abstract
The incidence of sub-fertility is higher in crossbred bulls compared to zebu bulls. In the present study, we analysed the metabolomic profile of seminal plasma from crossbred and zebu bulls and uncovered differentially expressed metabolites between these two breeds. Using a high-throughput LC-MS/MS-based approach, we identified 990 and 1,002 metabolites in crossbred and zebu bull seminal plasma respectively. After excluding the exogenous metabolites, we found that 50 and 68 putative metabolites were unique to crossbred and zebu bull seminal plasma, respectively, whilst 87 metabolites were common to both. After data normalisation, 63 metabolites were found to be dysregulated between crossbred and zebu bull seminal plasma. Observed pathways included Linoleic acid metabolism (observed metabolite was phosphatidylcholine) in crossbred bull seminal plasma whereas inositol phosphate metabolism (observed metabolites were phosphatidylinositol-3,4,5-trisphosphate/inositol 1,3,4,5,6-pentakisphosphate/myo-inositol hexakisphosphate) was observed in zebu bull seminal plasma. Abundance of Tetradecanoyl-CoA was significantly higher, whilst abundance of Taurine was significantly lower in crossbred bull seminal plasma. In conclusion, the present study established the seminal plasma metabolomic profile in crossbred and zebu bulls and suggest that increased lipid peroxidation coupled with low concentrations of antioxidants in seminal plasma might be associated with high incidence of sub-fertility in crossbred bulls.
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Affiliation(s)
- Mohua DasGupta
- Theriogenology Laboratory, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | - Arumugam Kumaresan
- Theriogenology Laboratory, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | - Kaustubh Kishor Saraf
- Theriogenology Laboratory, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | - Nilendu Paul
- Theriogenology Laboratory, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | | | - Gayathree Karthikkeyan
- Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - T S Keshava Prasad
- Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Prashant Kumar Modi
- Centre for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, India
| | - Kerekoppa Ramesha
- Dairy Production Section, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | - Ayyasamy Manimaran
- Dairy Production Section, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
| | - Sakthivel Jeyakumar
- Dairy Production Section, Southern Regional Station of ICAR-National Dairy Research Institute, Bengaluru, India
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Słowińska M, Sallem H, Clench MR, Ciereszko A. Metabolomic analysis of white and yellow seminal plasma in turkeys (Meleagris gallopavo). Poult Sci 2018; 97:1059-1065. [DOI: 10.3382/ps/pex366] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/05/2017] [Indexed: 12/17/2022] Open
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Gatticchi L, Cerra B, Scarpelli P, Macchioni L, Sebastiani B, Gioiello A, Roberti R. Selected cholesterol biosynthesis inhibitors produce accumulation of the intermediate FF-MAS that targets nucleus and activates LXRα in HepG2 cells. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:842-852. [DOI: 10.1016/j.bbalip.2017.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 05/07/2017] [Indexed: 01/23/2023]
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Li J, Wang X, Yuan Y, Long X, Bao J, Li X. An in vitro test system for evaluation of SCAP–SREBP pathway inhibitory activities of Traditional Chinese Medicines. RSC Adv 2017. [DOI: 10.1039/c7ra09521j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In vitro assay system demonstrates that Rhizoma Alismatis and Semen Cassiae show beneficial effects on inhibition of SCAP–SREBP pathway activities.
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Affiliation(s)
- Jianzong Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education
- College of Life Sciences
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Xin Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education
- College of Life Sciences
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Yuan Yuan
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education
- College of Life Sciences
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Xin Long
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education
- College of Life Sciences
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Jinku Bao
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education
- College of Life Sciences
- Sichuan University
- Chengdu 610065
- P. R. China
| | - Xin Li
- State Key Laboratory of Oral Diseases
- National Clinical Research Center for Oral Diseases
- West China Hospital of Stomatology
- Sichuan University
- Chengdu
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Ačimovič J, Rozman D. Steroidal triterpenes of cholesterol synthesis. Molecules 2013; 18:4002-17. [PMID: 23558541 PMCID: PMC6269928 DOI: 10.3390/molecules18044002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/19/2013] [Accepted: 03/27/2013] [Indexed: 11/21/2022] Open
Abstract
Cholesterol synthesis is a ubiquitous and housekeeping metabolic pathway that leads to cholesterol, an essential structural component of mammalian cell membranes, required for proper membrane permeability and fluidity. The last part of the pathway involves steroidal triterpenes with cholestane ring structures. It starts by conversion of acyclic squalene into lanosterol, the first sterol intermediate of the pathway, followed by production of 20 structurally very similar steroidal triterpene molecules in over 11 complex enzyme reactions. Due to the structural similarities of sterol intermediates and the broad substrate specificity of the enzymes involved (especially sterol-Δ24-reductase; DHCR24) the exact sequence of the reactions between lanosterol and cholesterol remains undefined. This article reviews all hitherto known structures of post-squalene steroidal triterpenes of cholesterol synthesis, their biological roles and the enzymes responsible for their synthesis. Furthermore, it summarises kinetic parameters of enzymes (Vmax and Km) and sterol intermediate concentrations from various tissues. Due to the complexity of the post-squalene cholesterol synthesis pathway, future studies will require a comprehensive meta-analysis of the pathway to elucidate the exact reaction sequence in different tissues, physiological or disease conditions. A major reason for the standstill of detailed late cholesterol synthesis research was the lack of several steroidal triterpene standards. We aid to this efforts by summarizing commercial and laboratory standards, referring also to chemical syntheses of meiosis-activating sterols.
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Affiliation(s)
- Jure Ačimovič
- Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, Institute of Biochemistry, University of Ljubljana, Zaloška 4, Ljubljana SI-1000, Slovenia.
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Keber R, Ačimovič J, Majdič G, Motaln H, Rozman D, Horvat S. Male germ cell-specific knockout of cholesterogenic cytochrome P450 lanosterol 14α-demethylase (Cyp51). J Lipid Res 2013; 54:1653-1661. [PMID: 23509403 DOI: 10.1194/jlr.m035717] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cytochrome P450 lanosterol 14α-demethylase (CYP51) and its products, meiosis-activating sterols (MASs), were hypothesized by previous in vitro studies to have an important role in regulating meiosis and reproduction. To test this in vivo, we generated a conditional male germ cell-specific knockout of the gene Cyp51 in the mouse. High excision efficiency of Cyp51 allele in germ cells resulted in 85-89% downregulation of Cyp51 mRNA and protein levels in germ cells. Quantitative metabolic profiling revealed significantly higher levels of CYP51 substrates lanosterol and 24,25-dihydrolanosterol and substantially diminished levels of MAS, the immediate products of CYP51. However, germ cell-specific ablation of Cyp51, leading to lack of MAS, did not affect testicular morphology, daily sperm production, or reproductive performance in males. It is plausible that due to the similar structures of cholesterol intermediates, previously proposed biological function of MAS in meiosis progression can be replaced by some other yet-unidentified functionally redundant lipid molecule(s). Our results using the germ cell-specific knockout model provide first in vivo evidence that the de novo synthesis of MAS and cholesterol in male germ cells is most likely not essential for spermatogenesis and reproduction and that MASs, originating from germ cells, do not cell-autonomously regulate spermatogenesis and fertility.
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Affiliation(s)
- Rok Keber
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
| | - Jure Ačimovič
- Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor Majdič
- Center for Animal Genomics, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Helena Motaln
- Department of Genetic Toxicology and Cancer Biology, National Institute of Biology, Ljubljana, Slovenia
| | - Damjana Rozman
- Centre for Functional Genomics and Bio-Chips, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Simon Horvat
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia; National Institute of Chemistry, Laboratory for Biotechnology, Ljubljana, Slovenia.
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Abstract
Mammalian spermatogenesis is a complex developmental program in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. One intriguing aspect of sperm production is the dynamic change in membrane lipid composition that occurs throughout spermatogenesis. Cholesterol content, as well as its intermediates, differs vastly between the male reproductive system and nongonadal tissues. Accumulation of cholesterol precursors such as testis meiosis-activating sterol and desmosterol is observed in testes and spermatozoa from several mammalian species. Moreover, cholesterogenic genes, especially meiosis-activating sterol-producing enzyme cytochrome P450 lanosterol 14α-demethylase, display stage-specific expression patterns during spermatogenesis. Discrepancies in gene expression patterns suggest a complex temporal and cell-type specific regulation of sterol compounds during spermatogenesis, which also involves dynamic interactions between germ and Sertoli cells. The functional importance of sterol compounds in sperm production is further supported by the modulation of sterol composition in spermatozoal membranes during epididymal transit and in the female reproductive tract, which is a prerequisite for successful fertilization. However, the exact role of sterols in male reproduction is unknown. This review discusses sterol dynamics in sperm maturation and describes recent methodological advances that will help to illuminate the complexity of sperm formation and function.
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Affiliation(s)
- Rok Keber
- Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Groblje 3, 1230 Domžale, Slovenia
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Lorbek G, Lewinska M, Rozman D. Cytochrome P450s in the synthesis of cholesterol and bile acids--from mouse models to human diseases. FEBS J 2011; 279:1516-33. [PMID: 22111624 DOI: 10.1111/j.1742-4658.2011.08432.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The present review describes the transgenic mouse models that have been designed to evaluate the functions of the cytochrome P450s involved in cholesterol and bile acid synthesis, as well as their link with disease. The knockout of cholesterogenic Cyp51 is embrionally lethal, with symptoms of Antley-Bixler syndrome occurring in mice, whereas the evidence for this association is conflicting in humans. Disruption of Cyp7a1 from classic bile acid synthesis in mice leads to either increased postnatal death or a milder phenotype with elevated serum cholesterol. The latter is similar to the case in humans, where CYP7A1 mutations associate with high plasma low-density lipoprotein and hepatic cholesterol content, as well as deficient bile acid excretion. Disruption of Cyp8b1 from an alternative bile acid pathway results in the absence of cholic acid and a reduced absorption of dietary lipids; however, the human CYP8B1 polymorphism fails to explain differences in bile acid composition. Unexpectedly, apparently normal Cyp27a1(-/-) mice still synthesize bile acids that originate from the compensatory pathway. In humans, CYP27A1 mutations cause cerebrotendinous xanthomatosis, suggesting that only mice can compensate for the loss of alternative bile acid synthesis. In line with this, Cyp7b1 knockouts are also apparently normal, whereas human CYP7B1 mutations lead to a congenital bile acid synthesis defect in children or spastic paraplegia in adults. Mouse knockouts of the brain-specific Cyp46a1 have reduced brain cholesterol excretion, whereas, in humans, CYP46A1 polymorphisms associate with cognitive impairment. At present, cytochrome P450 family 39 is poorly characterized. Despite important physiological differences between humans and mice, mouse models prove to be an invaluable tool for understanding the multifactorial facets of cholesterol and bile acid-related disorders.
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Affiliation(s)
- Gregor Lorbek
- Center for Functional Genomics and Bio-Chips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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Sonawane PJ, Sahu BS, Sasi BK, Geedi P, Lenka G, Mahapatra NR. Functional promoter polymorphisms govern differential expression of HMG-CoA reductase gene in mouse models of essential hypertension. PLoS One 2011; 6:e16661. [PMID: 21304971 PMCID: PMC3031630 DOI: 10.1371/journal.pone.0016661] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 01/10/2011] [Indexed: 11/18/2022] Open
Abstract
3-Hydroxy-3-methylglutaryl-coenzyme A [HMG-CoA] reductase gene (Hmgcr) is a susceptibility gene for essential hypertension. Sequencing of the Hmgcr locus in genetically hypertensive BPH (blood pressure high), genetically hypotensive BPL (blood pressure low) and genetically normotensive BPN (blood pressure normal) mice yielded a number of single nucleotide polymorphisms (SNPs). BPH/BPL/BPN Hmgcr promoter-luciferase reporter constructs were generated and transfected into liver HepG2, ovarian CHO, kidney HEK-293 and neuronal N2A cells for functional characterization of the promoter SNPs. The BPH-Hmgcr promoter showed significantly less activity than the BPL-Hmgcr promoter under basal as well as nicotine/cholesterol-treated conditions. This finding was consistent with lower endogenous Hmgcr expression in liver and lower plasma cholesterol in BPH mice. Transfection experiments using 5′-promoter deletion constructs (strategically made to assess the functional significance of each promoter SNP) and computational analysis predicted lower binding affinities of transcription factors c-Fos, n-Myc and Max with the BPH-promoter as compared to the BPL-promoter. Corroboratively, the BPH promoter-luciferase reporter construct co-transfected with expression plasmids of these transcription factors displayed less pronounced augmentation of luciferase activity than the BPL construct, particularly at lower amounts of transcription factor plasmids. Electrophoretic mobility shift assays also showed diminished interactions of the BPH promoter with HepG2 nuclear proteins. Taken together, this study provides mechanistic basis for the differential Hmgcr expression in these mouse models of human essential hypertension and have implications for better understanding the role of this gene in regulation of blood pressure.
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Affiliation(s)
- Parshuram J. Sonawane
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Bhavani S. Sahu
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Binu K. Sasi
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Parimala Geedi
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Govinda Lenka
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
| | - Nitish R. Mahapatra
- Cardiovascular Genetics Laboratory, Department of Biotechnology, Indian Institute of Technology Madras, Chennai, India
- * E-mail:
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Horvat S, Mcwhir J, Rozman D. Defects in cholesterol synthesis genes in mouse and in humans: lessons for drug development and safer treatments. Drug Metab Rev 2011; 43:69-90. [DOI: 10.3109/03602532.2010.540580] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Schmelzer C, Okun JG, Haas D, Higuchi K, Sawashita J, Mori M, Döring F. The reduced form of coenzyme Q10 mediates distinct effects on cholesterol metabolism at the transcriptional and metabolite level in SAMP1 mice. IUBMB Life 2010; 62:812-8. [DOI: 10.1002/iub.388] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Fon Tacer K, Pompon D, Rozman D. Adaptation of cholesterol synthesis to fasting and TNF-alpha: profiling cholesterol intermediates in the liver, brain, and testis. J Steroid Biochem Mol Biol 2010; 121:619-25. [PMID: 20206258 DOI: 10.1016/j.jsbmb.2010.02.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/16/2010] [Accepted: 02/24/2010] [Indexed: 12/18/2022]
Abstract
Key players in pathogenesis of metabolic disorders are disturbed cholesterol balance and inflammation. In addition to cholesterol also sterol intermediates are biologically active, however, surprisingly little is known about their synthesis and roles. The aim of our study was to assess the interplay between the inflammatory cytokine TNF-alpha and cholesterol synthesis by measuring cholesterol and its intermediates in the liver, brain, and testis. Liquid chromatography-mass spectrometry has been applied to profile sterols of normally fed mice, during fasting and after TNF-alpha administration. In mice on normal chow diet, sterols other than cholesterol represent 0.5% in the liver, 1% in brain and 5% in testis. In the liver only 7-dehydrocholesterol, lanosterol and desmosterol were detected. Major sterol intermediates of the brain are desmosterol, testis meiosis activating sterol (T-MAS), and 7-dehydrocholesterol while in testis T-MAS predominates (4%), followed by desmosterol, lanosterol, 7-dehydrocholesterol and others. In 20h fasting there is no significant change in cholesterol of the three tissues, and no significant change in intermediates of the liver. In the brain sterol intermediates are lowered (significant for zymosterol) while in the testis the trend is opposite. TNF-alpha provokes a significant raise of some intermediates whereas the level of cholesterol is again unchanged. The proportion of sterols in the liver rises from 0.5% in controls to 1.2% in TNF-alpha-treated mice, which is in accordance with published expression profiling data. In conclusion, our data provide novel insights into the interaction between the inflammatory cytokine TNF-alpha and the tissue-specific cholesterol biosynthesis of the liver, brain and testis.
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Affiliation(s)
- Klementina Fon Tacer
- Center for Functional Genomic and Biochips, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Zaloska 4, SI-1000 Ljubljana, Slovenia
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Wang F, Yang J, Wang H, Xia G. Gonadotropin-regulated expressions of lanosterol 14alpha-demethylase, sterol Delta14-reductase and C-4 sterol methyl oxidase contribute to the accumulation of meiosis-activating sterol in rabbit gonads. Prostaglandins Other Lipid Mediat 2010; 92:25-32. [PMID: 20193772 DOI: 10.1016/j.prostaglandins.2010.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Revised: 02/19/2010] [Accepted: 02/19/2010] [Indexed: 11/25/2022]
Abstract
Meiosis-activating sterol (MAS), the intermediate of cholesterol biosynthesis, is an important lipophilic molecule mediating gonadotropins' action in inducing oocyte meiotic resumptions in various mammalian species. With respect to MAS's physiological relevance during oocyte maturation in the rabbit, early study has demonstrated that luteinizing hormone (LH), but not follicle stimulating hormone (FSH) can induce FF-MAS accumulation facilitating oocyte maturation in rabbits. However, the potential underlying mechanism for the MAS accumulation in the rabbit gonad remained unclear. We hypothesized that differential expression of MAS synthetic and metabolic enzymes would contribute to the timely MAS accumulation in the rabbit gonad. To address this issue, in the present investigation, we first cloned the cDNAs encoding there pre- and post-MAS enzymes, lanosterol 14alpha-demethylase (CYP51), sterol Delta14-reductase (14-SR) and C-4 sterol methyl oxidase (C4MO), respectively, using rapid amplification of cDNA ends (RACE) cloning, and then performed northern hybridization experiments to explore their expression profiles in the rabbit ovary, testis, and various other tissues. We observed that CYP51 expression was significantly upregulated only by LH/hCG in the antral follicle exhibiting its peak levels in preovulatory follicles; whereas both FSH and LH significantly downregulated 14-SR expression with the progression of antral follicular development. These findings provided here novel evidence that an inverse upregulation of CYP51 and downregulation of 14-SR expression under FSH/LH stimulation functions as the machinery for FF-MAS accumulation in preovulatory follicles prior to ovulation in the rabbit.
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Affiliation(s)
- Fengchao Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.
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Kőhalmy K, Rozman D, Pascussi JM, Sárváry E, Monostory K. Crosstalk between cholesterol homeostasis and drug metabolism. Orv Hetil 2008; 149:1283-9. [DOI: 10.1556/oh.2008.28329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Napjainkban a cardiovascularis megbetegedések vezető halálozási oknak számítanak világszerte. A szív- és érrendszeri megbetegedések kialakulásában jelentős szerepet játszik a magas szérumkoleszterin-szint, illetve az atherosclerosis. A vér koleszterinszintjének csökkentésével kedvezően befolyásolható a káros folyamatok kialakulása, és a már kialakult betegségekben is javulás érhető el. Az általánosan alkalmazott sztatinalapú gyógyszeres terápia ade novokoleszterin-bioszintézist gátolja a májban. Más hatóanyagok (például ezetimib) a koleszterin táplálékból történő felszívódását gátolják. A leghatékonyabb megoldást ezek kombinált alkalmazása jelentheti. A gyógyszeres terápia során azonban figyelembe kell venni, hogy számos vegyület (gyógyszer) képes specifikusan megváltoztatni – a koleszterinhomeosztázis fenntartásában szerepet játszó enzimek mellett – a gyógyszer-metabolizáló enzimek indukciójával a citokróm P450 enzimek mennyiségét is (például sztatinok), ami a terápia módosítását teszi szükségessé. A koleszterin-anyagcsere és a gyógyszer-metabolizmus szabályozásában ugyanis több kapcsolódási pont is található. A kapcsolat az úgynevezett nukleáris receptorokon keresztül valósul meg, ezért a koleszterinhomeosztázis és a gyógyszer-metabolizmus közti összefüggés megértése és ismereteink bővítése elengedhetetlen egy megfelelő terápiás stratégia kidolgozásához, illetve új gyógyszerek fejlesztéséhez.
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Affiliation(s)
- Krisztina Kőhalmy
- 1 Magyar Tudományos Akadémia, Kémiai Kutatóközpont Farmakobiokémiai Osztály Budapest Pusztaszeri út 59–67. 1025
| | | | - Jean-Marc Pascussi
- 3 Université Montpellier Institut National de la Santé et de la Recherche Médicale Montpellier Franciaország
| | - Enikő Sárváry
- 4 Semmelweis Egyetem, Általános Orvostudományi Kar Transzplantációs és Sebészeti Klinika Budapest
| | - Katalin Monostory
- 1 Magyar Tudományos Akadémia, Kémiai Kutatóközpont Farmakobiokémiai Osztály Budapest Pusztaszeri út 59–67. 1025
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17
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Korošec T, Ačimovič J, Seliškar M, Kocjan D, Tacer KF, Rozman D, Urleb U. Novel cholesterol biosynthesis inhibitors targeting human lanosterol 14α-demethylase (CYP51). Bioorg Med Chem 2008; 16:209-21. [DOI: 10.1016/j.bmc.2007.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 09/15/2007] [Accepted: 10/01/2007] [Indexed: 11/29/2022]
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18
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Kiyose C, Ogino S, Kubo K, Takeuchi M, Saito M. Relationship between Garcinia cambogia-Induced Impairment of Spermatogenesis and Meiosis-Activating Sterol Production in Rat Testis. J Clin Biochem Nutr 2006. [DOI: 10.3164/jcbn.38.180] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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19
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Kiyose C, Kubo K, Saito M. Effect of Garcinia cambogia Administration on Female Reproductive Organs in Rats. J Clin Biochem Nutr 2006. [DOI: 10.3164/jcbn.38.188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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20
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Wang F, Shen Y, Song X, Xia G, Chen X, Zhou B, Lei L. cDNA Cloning, Genomic Structure and Expression Analysis of the Bovine Lanosterol 14.ALPHA.-Demethylase (CYP51) in Gonads. Biol Pharm Bull 2006; 29:430-6. [PMID: 16508140 DOI: 10.1248/bpb.29.430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Meiosis activating sterol (MAS), the intermediate of cholesterol biosynthesis, is an important substance to stimulate oocytes maturation in FSH-induced signal transduction pathway. Lanosterol 14alpha-demethylase (CYP51) converts lanosterol to MAS. Although MAS is firstly isolated from bovine testis, the information about bovine CYP51 gene and its expression is little. In present studies, the cDNA cloning, genomic structure, chromosomal mapping, and expression patterns of bovine CYP51 were demonstrated. The cDNA coding bovine CYP51 contains a 1509 bp open reading frame and a 1119 bp 3' untranslated region. And the bovine CYP51 gene includes 10 exons and spans about 17 kb. Screening the cattle RH5000 panel bovine CYP51 is mapped to chromosome 4 (0cR). The sequenced promoter region is TATA-less and contains several highly conserved regulatory elements, such as GC-box, cAMP-responsive elements (CRE), sterol regulatory element (SRE) which is important fragment for its transcription. No evidence of processed pseudogenes is found using long PCR and Southern blot. Northern blot analysis reveals that an approximately 2.7 kb mRNA is expressed in all the examined bovine tissues, while a 1.8 kb mRNA is found only in the mature bovine testis where the MAS is accumulated. Immunochemistry analysis shows that leydig cells express the highest level of the CYP51 protein in testis. Among different stages follicles it is localized primarily to the oocytes with the level varying slightly. Granulosa cells of primordial, primary and secondary follicles show background staining. While granulosa cells facing the antrum and cumulus granulosa cells of antral follicles show considerably heavier staining. The highest level is expressed in corpus lutea. These data indicate a stage- and cell type-specific expression of CYP51 protein in bovine oogenesis.
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Affiliation(s)
- Fengchao Wang
- College of Biological Science, China Agricultural University, Beijing, PR China
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21
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Fink M, Acimovic J, Rezen T, Tansek N, Rozman D. Cholesterogenic lanosterol 14alpha-demethylase (CYP51) is an immediate early response gene. Endocrinology 2005; 146:5321-31. [PMID: 16123160 DOI: 10.1210/en.2005-0781] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Lanosterol 14alpha-demethylase (CYP51) responds to cholesterol feedback regulation through sterol regulatory element binding proteins (SREBPs). The proximal promoter of CYP51 contains a conserved region with clustered regulatory elements: GC box, cAMP-response elements (CRE-like), and sterol regulatory element (SRE). In lipid-rich (SREBP-poor) conditions, the CYP51 mRNA drops gradually, the promoter activity is diminished, and no DNA-protein complex is observed at the CYP51-SRE1 site. The majority of cAMP-dependent transactivation is mediated through a single CRE (CYP51-CRE2). Exposure of JEG-3 cells to forskolin, a mediator of the cAMP-dependent signaling pathway, provokes an immediate early response of CYP51, which has not been described before for any cholesterogenic gene. The CYP51 mRNA increases up to 4-fold in 2 h and drops to basal level after 4 h. The inducible cAMP early repressor (ICER) is involved in attenuation of transcription. Overexpressed CRE-binding protein (CREB)/CRE modulator (CREM) transactivates the mouse/human CYP51 promoters containing CYP51-CRE2 independently of SREBPs, and ICER decreases the CREB-induced transcription. Besides the increased CYP51 mRNA, forskolin affects the de novo sterol biosynthesis in JEG-3 cells. An increased consumption of lanosterol, a substrate of CYP51, is observed together with modulation of the postlanosterol cholesterogenesis, indicating that cAMP-dependent stimuli cross-talk with cholesterol feedback regulation. CRE-2 is essential for cAMP-dependent transactivation, whereas SRE seems to be less important. Interestingly, when CREB is not limiting, the increasing amounts of SREBP-1a fail to transactivate the CYP51 promoter above the CREB-only level, suggesting that hormones might have an important role in regulating cholesterogenesis in vivo.
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Affiliation(s)
- Martina Fink
- Medical Center for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Slovenia
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22
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Ishikawa T, Hwang K, Lazzarino D, Morris PL. Sertoli cell expression of steroidogenic acute regulatory protein-related lipid transfer 1 and 5 domain-containing proteins and sterol regulatory element binding protein-1 are interleukin-1beta regulated by activation of c-Jun N-terminal kinase and cyclooxygenase-2 and cytokine induction. Endocrinology 2005; 146:5100-11. [PMID: 16123165 DOI: 10.1210/en.2005-0567] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In testicular Sertoli cells, IL-1beta regulates steroid, lactate, and transferrin secretion; although each influences germ cell development and spermatogenesis, little is known about the signaling mechanisms involved. In other cell types, IL-1beta potently induces reactive oxygen species and/or cyclooxygenase-2 (COX-2). In contrast, in Sertoli cells, IL-1beta does not generate reactive oxygen species, but rapidly phosphorylates c-Jun-NH(2)-terminal kinase (JNK), but not p44/42 or p38 MAPK. Phosphorylated JNK stimulates COX-2 activity, mediating the expression of ILs and steroidogenic acute regulatory (StAR)-related (StAR-related lipid transfer protein domain containing) proteins D1 and D5, but not D4. In a time- and dose-dependent manner, IL-1beta rapidly increases levels of COX-2 mRNA (2-fold); induction of COX-2 protein (50-fold) requires de novo protein synthesis. Concomitantly, increases in IL-1alpha, IL-6, and IL-1beta mRNAs (1-3 h) are observed. As StAR-related lipid transfer protein domain containing protein 1 (StARD1) mRNA decreases, StARD5 mRNA increases; substantial recovery phase induction of StARD1 mRNA above control is noted (24 h). Inhibition of JNK or COX-2 activities prevents IL-1beta induction of IL and StARD5 mRNAs and subsequent increases in StARD1 mRNA (24 h), indicating that these effects depend on the activation of both enzymes. StARD1 and D5 protein levels are significantly altered, consistent with posttranscriptional and posttranslational regulation. IL-1beta rapidly decreases levels of precursor and mature sterol regulatory element-binding protein-1, changes not altered by cycloheximide, suggesting coordinate regulation of StARD1 and -D5, but not StARD4, expression. These data demonstrate that JNK and COX-2 activities regulate Sertoli cytokines and particularly START domain-containing proteins, suggesting protective stress responses, including transcription and protein and lipid regulation, within this specialized epithelium.
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Affiliation(s)
- Tomomoto Ishikawa
- Center for Biomedical Research, The Population Council, New York, New York 10021, USA
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23
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Rozman D, Seliskar M, Cotman M, Fink M. Pre-cholesterol precursors in gametogenesis. Mol Cell Endocrinol 2005; 234:47-56. [PMID: 15836952 DOI: 10.1016/j.mce.2004.11.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2004] [Accepted: 11/09/2004] [Indexed: 10/25/2022]
Abstract
Meiosis activating sterols (MAS) are biologically active post-lanosterol intermediates of cholesterol biosynthesis that are synthetized primarily in the gonads, including the sperm. MAS reinitiate the meiosis of oocytes in vitro while in vivo they seem to contribute to the oocyte quality and the progression of meiosis. The mRNAs for the MAS-producing enzyme lanosterol 14alpha-demethylase (CYP51) arise by alternative poly (A) signal selection. Only signals with low cleavage activity are used in the testis. Translation of mammalian CYP51s starts at one of the tandem in-frame ATGs. CYP51 protein of the bull is shorter compared to the human due to the usage of a more downstream translation start site. CYP51 proteins are post-translationally modified by glycosylations in the Golgi and on acrosomal membranes of the sperm. Green fluorescence protein-based ex vivo system has been developed to aid studying the intracellular transport of the MAS-producing CYP51. The influence of the post-translational modifications on MAS-synthesizing capacity is under investigation.
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Affiliation(s)
- Damjana Rozman
- Medical Centre for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, SI-1000 Ljubljana, Slovenia.
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24
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Wang H, San Agustin JT, Witman GB, Kilpatrick DL. Novel role for a sterol response element binding protein in directing spermatogenic cell-specific gene expression. Mol Cell Biol 2004; 24:10681-8. [PMID: 15572673 PMCID: PMC533981 DOI: 10.1128/mcb.24.24.10681-10688.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 08/01/2004] [Accepted: 09/26/2004] [Indexed: 11/20/2022] Open
Abstract
Sperm are highly specialized cells, and their formation requires the synthesis of a large number of unique mRNAs. However, little is known about the transcriptional mechanisms that direct male germ cell differentiation. Sterol response element binding protein 2gc (SREBP2gc) is a spermatogenic cell-enriched isoform of the ubiquitous transcription factor SREBP2, which in somatic cells is required for homeostatic regulation of cholesterol. SREBP2gc is selectively enriched in spermatocytes and spermatids, and, due to its novel structure, its synthesis is not subject to cholesterol feedback control. This suggested that SREBP2gc has unique cell- and stage-specific functions during spermatogenesis. Here, we demonstrate that this factor activates the promoter for the spermatogenesis-related gene proacrosin in a cell-specific manner. Multiple SREBP2gc response elements were identified within the 5'-flanking and proximal promoter regions of the proacrosin promoter. Mutating these elements greatly diminished in vivo expression of this promoter in spermatogenic cells of transgenic mice. These studies define a totally new function for an SREBP as a transactivator of male germ cell-specific gene expression. We propose that SREBP2gc is part of a cadre of spermatogenic cell-enriched isoforms of ubiquitously expressed transcriptional coregulators that were specifically adapted in concert to direct differentiation of the male germ cell lineage.
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Affiliation(s)
- Hang Wang
- Department of Physiology, University of Massachusetts Medical School, 55 Lake Avenue N, Worcester, MA 01655-0127. USA
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25
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Fon Tacer K, Kalanj-Bognar S, Waterman MR, Rozman D. Lanosterol metabolism and sterol regulatory element binding protein (SREBP) expression in male germ cell maturation. J Steroid Biochem Mol Biol 2003; 85:429-38. [PMID: 12943732 DOI: 10.1016/s0960-0760(03)00191-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Expression of genes involved in cholesterol biosynthesis in male germ cells is insensitive to the negative cholesterol feedback regulation, in contrast to cholesterol level-sensitive/sterol regulatory element binding protein (SREBP)-dependent gene regulation in somatic cells. The role of sterol regulatory element binding proteins in spermatogenic cells was an enigma until recently, when a soluble, 55kDa cholesterol-insensitive form of SREBP2 (SREBP2gc) was discovered [Mol. Cell. Endocrinol. 22 (2002) 8478], being translated from a germ cell-specific SREBP2 mRNA. Our RT-PCR results also show that SREBP2 as well as SREBP1c mRNAs are detectable in prepubertal and postpubertal male germ cells while SREBP1a is not detected. Surprisingly, three SREBP2 immunoreactive proteins (72, 63 and 55kDa), that are not present in mouse liver nuclei, reside in testis nuclei of prepubertal and adult mice. The 55kDa protein is likely SREBP2gc, the other two isoforms are novel. HPLC measurements in liver and testes of fasted prepubertal and postpubertal mice showed no significant difference in cholesterol level. However, FF-MAS and lanosterol/testis-meiosis activating sterol (T-MAS) intermediates that are detectable mainly in testes, increase in fasted postpubertal mice which coincides well with the elevated level of 68kDa SREBP2. Similar to SREBP2gc, the two novel SREBP2 immunoreactive proteins seem to be insensitive to the level of cholesterol.
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Affiliation(s)
- Klementina Fon Tacer
- Institute of Biochemistry, Medical Center for Molecular Biology, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia
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26
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Debeljak N, Fink M, Rozman D. Many facets of mammalian lanosterol 14alpha-demethylase from the evolutionarily conserved cytochrome P450 family CYP51. Arch Biochem Biophys 2003; 409:159-71. [PMID: 12464255 DOI: 10.1016/s0003-9861(02)00418-6] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lanosterol 14alpha-demethylase is a cytochrome P450 enzyme of the cholesterol biosynthetic pathway belonging to the CYP51 gene family which is the most evolutionarily conserved member of the CYP superfamily. Mammalian (human, mouse, rat, pig) CYP51 genes are unique in sharing several common characteristics: highly conserved exon/intron borders and proximal promoter structures, ubiquitous expression at the highest level in the testis, and appearance of testis-specific transcripts that arise from differential polyadenylation site usage. CYP51 protein demethylates lanosterol to form follicular fluid meiosis-activating sterol, FF-MAS, which is, besides being an intermediate of cholesterol biosynthesis, also a signaling sterol that accumulates in ovaries. CYP51 protein resides in the endoplasmatic reticulum of most cells and also in acrosomal membranes of spermatids where transport through the Golgi apparatus is suggested. While sterol regulatory element binding protein (SREBP)-dependent transcriptional regulation of CYP51 contributes to synthesis of cholesterol, the germ-cell-specific cAMP/CREMtau-dependent upregulation might contribute to increased production of MAS.
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Affiliation(s)
- Natasa Debeljak
- Medical Center for Molecular Biology, Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, Slovenia
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27
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Wang H, Liu F, Millette CF, Kilpatrick DL. Expression of a novel, sterol-insensitive form of sterol regulatory element binding protein 2 (SREBP2) in male germ cells suggests important cell- and stage-specific functions for SREBP targets during spermatogenesis. Mol Cell Biol 2002; 22:8478-90. [PMID: 12446768 PMCID: PMC139869 DOI: 10.1128/mcb.22.24.8478-8490.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Cholesterol biosynthesis in somatic cells is controlled at the transcriptional level by a homeostatic feedback pathway involving sterol regulatory element binding proteins (SREBPs). These basic helix-loop-helix (bHLH)-Zip proteins are synthesized as membrane-bound precursors, which are cleaved to form a soluble, transcriptionally active mature SREBP that regulates the promoters for genes involved in lipid synthesis. Homeostasis is conferred by sterol feedback inhibition of this maturation process. Previous work has demonstrated the expression of SREBP target genes in the male germ line, several of which are highly up-regulated during specific developmental stages. However, the role of SREBPs in the control of sterol regulatory element-containing promoters during spermatogenesis has been unclear. In particular, expression of several of these genes in male germ cells appears to be insensitive to sterols, contrary to SREBP-dependent gene regulation in somatic cells. Here, we have characterized a novel isoform of the transcription factor SREBP2, which is highly enriched in rat and mouse spermatogenic cells. This protein, SREBP2gc, is expressed in a stage-dependent fashion as a soluble, constitutively active transcription factor that is not subject to feedback control by sterols. These findings likely explain the apparent sterol-insensitive expression of lipid synthesis genes during spermatogenesis. Expression of a sterol-independent, constitutively active SREBP2gc in the male germ line may have arisen as a means to regulate SREBP target genes in specific developmental stages. This may reflect unique roles for cholesterol synthesis and other functional targets of SREBPs during spermatogenesis.
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Affiliation(s)
- Hang Wang
- Department of Physiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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28
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Halder SK, Fink M, Waterman MR, Rozman D. A cAMP-responsive element binding site is essential for sterol regulation of the human lanosterol 14alpha-demethylase gene (CYP51). Mol Endocrinol 2002; 16:1853-63. [PMID: 12145339 DOI: 10.1210/me.2001-0262] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Lanosterol 14alpha-demethylase (CYP51) is involved in the cholesterol biosynthesis pathway, producing follicular fluid meiosis-activating sterol. The promoter region of the human CYP51 gene contains a cluster of regulatory elements including GC box, cAMP response element (CRE), and sterol regulatory element (SRE). To understand the mechanism of sterol-dependent regulation of this gene, several constructs of the promoter with the reporter gene have been tested in JEG-3 cells containing overexpressed human sterol regulatory element binding protein (SREBP)-1a. The wild-type construct showed maximal SREBP-dependent activation, most of which is retained when the GC box is mutated/deleted. Activation is abolished when either CRE or SRE are removed/mutated. Furthermore, mutation of CRE abolishes SREBP-dependent activation after overexpression of SREBP-1a and CRE binding protein (CREB). This shows that CRE is essential, and that under ex vivo conditions CREB and SREBP cooperate in transactivating CYP51. Interestingly, protein kinase A shows a marked stimulation of the CYP51 promoter activity when overexpressed together with SREBP-1a but not when overexpressed with CREB, suggesting phosphorylation of SREBP-1a. Using a DNA probe containing all three regulatory elements, it is found that SREBP-1a, a CREB-like factor, and specificity protein (Sp1) all probably bind the CYP51 promoter. While SREBP-1a and the CRE-bound proteins are essential for the SREBP-dependent response, Sp1 apparently functions only to maximize sterol regulation of CYP51. To date this is the first gene in which cooperation between SREBP and a CREB/CRE modulator/activating transcription factor family transcription factor is shown to be essential and sufficient for SREBP-dependent activation.
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Affiliation(s)
- Sunil K Halder
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146, USA
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29
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Soccio RE, Adams RM, Romanowski MJ, Sehayek E, Burley SK, Breslow JL. The cholesterol-regulated StarD4 gene encodes a StAR-related lipid transfer protein with two closely related homologues, StarD5 and StarD6. Proc Natl Acad Sci U S A 2002; 99:6943-8. [PMID: 12011452 PMCID: PMC124508 DOI: 10.1073/pnas.052143799] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using cDNA microarrays, we identified StarD4 as a gene whose expression decreased more than 2-fold in the livers of mice fed a high-cholesterol diet. StarD4 expression in cultured 3T3 cells was also sterol-regulated, and known sterol regulatory element binding protein (SREBP)-target genes showed coordinate regulation. The closest homologues to StarD4 were two other StAR-related lipid transfer (START) proteins named StarD5 and StarD6. StarD4, StarD5, and StarD6 are 205- to 233-aa proteins consisting almost entirely of START domains. These three constitute a subfamily among START proteins, sharing approximately 30% amino acid identity with one another, approximately 20% identity with the cholesterol-binding START domains of StAR and MLN64, and less than 15% identity with phosphatidylcholine transfer protein (PCTP) and other START domains. StarD4 and StarD5 were expressed in most tissues, with highest levels in liver and kidney, whereas StarD6 was expressed exclusively in the testis. In contrast to StarD4, expression of StarD5 and MLN64 was not sterol-regulated. StarD4, StarD5, and StarD6 may be involved in the intracellular transport of sterols or other lipids.
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Affiliation(s)
- Raymond E Soccio
- Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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