CDDO Increases Translation of CCAAT Enhancer Binding Protein alpha To Induce Granulocytic Differentiation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2458-2458 ◽  
Author(s):  
Steffen Koschmieder ◽  
Francesco D′Alo′ ◽  
Hanna Radomska ◽  
Susumu Kobayashi ◽  
Elena Levantini ◽  
...  
Keyword(s):  
De Novo ◽  
Binding Protein ◽  
Northern Blotting ◽  
Granulocytic Differentiation ◽  
Protein Levels ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Eif2 Alpha

Abstract The triterpenoid 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) is a novel antineoplastic drug which induces apoptosis of a wide variety of tumor cells in vitro and in vivo and leads to granulocytic differentiation of hematopoietic progenitor cells. We studied the effect of CDDO on CCAAT enhancer binding protein alpha (CEBPA), a transcription factor which is critical for granulocytic differentiation. In HL60 myeloblastic cells, CDDO (0.01 to 2 uM) dose-dependently decreased the number of cells in culture and increased the fraction of apoptotic cells. However, at doses which did not induce apoptosis, CDDO increased the number of granulocytic cells, as assessed by morphology, NBT assay, and FACS, and Northern blotting showed an increase of GCSFR and a decrease of c-myc mRNA. Phagocytosis of FITC-labeled E. coli bacteria by these cells was enhanced by CDDO. While CEBPA mRNA was decreased, CEBPA protein was significantly increased within 24 hours of treatment, and this was not abrogated by preincubation with the caspase inhibitor Z-DEVD-fmk, again suggesting that these effects were independent of apoptosis. CDDO increased the ratio of the transcriptionally active isoform p42 and the inactive p30 isoform 3-fold, and gel shift assays showed enhanced DNA binding to a GCSFR promoter probe. Since eukaryotic translation initiation factors (eIF) have been described to alter the CEBPA protein isoform ratio, we studied the effects of CDDO on eiF2 alpha and eiF4E activity. CDDO increased the phosphorylation of eIF4E and decreased the phosphorylation of eIF2 alpha within 5 hours of treatment, and this was associated with an increase of the p42/p30 CEBPA ratio. In the presence of the translation inhibitor cycloheximide, CEBPA protein levels decreased after 2 hours, suggesting that CDDO did not stabilize CEBPA and that de novo protein synthesis was required for the observed effects. The effect of CDDO on the p42/p30 ratio was mimicked by 2-AP, which inhibits eIF2 alpha phosphorylation, but was independent of PPARgamma and TGFß pathways, as demonstrated by preincubation with GW9662, or TGFß1, respectively. In primary blasts from patients with acute myeloid leukemia (AML), the p42/p30 ratio of CEBPA was enhanced by CDDO treatment. In conclusion, CDDO leads to granulocytic differentiation and translational induction of CEBPA protein. Since CEBPA function is impaired in many patients with AML, CDDO may provide a novel treatment approach for these patients.

scholarly journals Impairment of Natural Killer Cytotoxic Activity and Interferon γ Production in Ccaat/Enhancer Binding Protein γ–Deficient Mice

1999 ◽  
Vol 190 (11) ◽  
pp. 1573-1582 ◽  
Author(s):  
Tsuneyasu Kaisho ◽  
Hiroko Tsutsui ◽  
Takashi Tanaka ◽  
Tohru Tsujimura ◽  
Kiyoshi Takeda ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Nk Cells ◽  
Natural Killer ◽  
Binding Protein ◽  
Normal Surface ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Ifn Γ

We have investigated in vivo roles of CCAAT/enhancer binding protein γ (C/EBPγ) by gene targeting. C/EBPγ-deficient (C/EBPγ2/−) mice showed a high mortality rate within 48 h after birth. To analyze the roles of C/EBPγ in lymphoid lineage cells, bone marrow chimeras were established. C/EBPγ2/− chimeras showed normal T and B cell development. However, cytolytic functions of their splenic natural killer (NK) cells after stimulation with cytokines such as interleukin (IL)-12, IL-18, and IL-2 were significantly reduced as compared with those of control chimera NK cells. In addition, the ability of C/EBPγ−/− chimera splenocytes to produce interferon (IFN)-γ in response to IL-12 and/or IL-18 was markedly impaired. NK cells could be generated in vitro with normal surface marker expression in the presence of IL-15 from C/EBPγ2/− newborn spleen cells. However, they also showed lower cytotoxic activity and IFN-γ production when stimulated with IL-12 plus IL-18 than control NK cells, as observed in C/EBPγ2/− chimera splenocytes. In conclusion, our study reveals that C/EBPγ is a critical transcription factor involved in the functional maturation of NK cells.

A rapamycin derivative (everolimus) controls proliferation through down-regulation of truncated CCAAT enhancer binding protein β and NF-κB activity in Hodgkin and anaplastic large cell lymphomas

Blood ◽  
2005 ◽  
Vol 106 (5) ◽  
pp. 1801-1807 ◽  
Author(s):  
Franziska Jundt ◽  
Nina Raetzel ◽  
Christine Müller ◽  
Cornelis F. Calkhoven ◽  
Katharina Kley ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Binding Protein ◽  
Mammalian Target Of Rapamycin ◽  
Large Cell ◽  
Nuclear Factor Κb ◽  
Survival Pathways ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein

Abstract The immunosuppressive macrolide rapamycin and its derivative everolimus (SDZ RAD, RAD) inhibit the mammalian target of rapamycin (mTOR) signaling pathway. In this study, we provide evidence that RAD has profound antiproliferative activity in vitro and in NOD/SCID mice in vivo against Hodgkin lymphoma (HL) and anaplastic large cell lymphoma (ALCL) cells. Moreover, we identified 2 molecular mechanisms that showed how RAD exerts antiproliferative effects in HL and ALCL cells. RAD down-regulated the truncated isoform of the transcription factor CCAAT enhancer binding protein β (C/EBPβ), which is known to disrupt terminal differentiation and induce a transformed phenotype. Furthermore, RAD inhibited constitutive nuclear factor κB (NF-κB) activity, which is a critical survival factor of HL cells. Pharmacologic inhibition of the mTOR pathway by RAD therefore interferes with essential proliferation and survival pathways in HL and ALCL cells and might serve as a novel treatment option. (Blood. 2005;106: 1801-1807)

scholarly journals Genistein inhibits CCAAT/enhancer-binding protein β (C/EBPβ) activity and 3T3-L1 adipogenesis by increasing C/EBP homologous protein expression

2002 ◽  
Vol 367 (1) ◽  
pp. 203-208 ◽  
Author(s):  
Anne W. HARMON ◽  
Yashomati M. PATEL ◽  
Joyce B. HARP
Keyword(s):  
Protein Expression ◽  
Kinase Inhibitor ◽  
Binding Protein ◽  
Dominant Negative ◽  
Peroxisome Proliferator ◽  
Homologous Protein ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein

The tyrosine kinase inhibitor genistein inhibits 3T3-L1 adipogenesis when present during the first 72h of differentiation. In this report, we investigated the underlying mechanisms involved in the anti-adipogenic effects of genistein. We found that genistein blocked the DNA binding and transcriptional activity of CCAAT/enhancer-binding protein β (C/EBPβ) during differentiation by promoting the expression of C/EBP homologous protein, a dominant-negative member of the C/EBP family. Loss of C/EBPβ activity was manifested as a loss of differentiation-induced C/EBPα and peroxisome-proliferator-activated receptor γ protein expression and a dramatic reduction in lipid accumulation. Further, we documented for the first time that C/EBPβ was tyrosine-phosphorylated in vivo during differentiation and in vitro by activated epidermal growth factor receptor. Genistein inhibited both of these events. Collectively, these results indicate that genistein blocks adipogenesis and C/EBPβ activity by increasing the level of C/EBP homologous protein and possibly by inhibiting the tyrosine phosphorylation of C/EBPβ.

scholarly journals Ρύθμιση της ανοσοαπάντησης στις ιδιοπαθείς φλεγμονώδεις νόσους του εντέρου και σε πειραματικά μοντέλα κολίτιδας

2018 ◽  
Author(s):  
Ελένη Κοντάκη
Keyword(s):  
Sulfonic Acid ◽  
Ex Vivo ◽  
Binding Protein ◽  
Suppressor Cells ◽  
Trinitrobenzene Sulfonic Acid ◽  
Hla Dr ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein

Οι Ιδιοπαθείς Φλεγμονώδεις Νόσοι του Εντέρου (ΙΦΝΕ) είναι χρόνιες φλεγμονώδεις παθήσεις του πεπτικού σωλήνα, με υποτροπίαζοντα ή προοδευτικό χαρακτήρα που επηρρεάζουν εκατομμύρια ανθρώπων παγκοσμίως. Ο όρος ΙΦΝΕ περιλαμβάνει τη νόσο του Crohn και την ελκώδη κολίτιδα. Η ηλικία εμφάνισης της νόσου τοποθετείται συνήθως στη δεύτερη και τρίτη δεκαετία της ζωής, με την πλειονότητα των ασθενών να εμφανίζουν κλινική πορεία χαρακτηριζόμενη από υφέσεις και εξάρσεις. Αν και η ακριβής αιτιολογία των ΙΦΝΕ δεν έχει πλήρως αποσαφηνιστεί, θεωρείται νόσος πολυπαραγοντική. Φαίνεται ότι υπάρχει γενετική προδιάθεση, με υπεύθυνα συγκεκριμένα γονίδια που πιθανώς είναι ο πλέον σπουδαίος παράγοντας κινδύνου εμφάνισης των ΙΦΝΕ. Επιπλέον, η αλλαγή του μικροβιώματος δημιουργεί δυσβίωση μεταξύ ξενιστή και μικροβιώματος του εντέρου και αποτελεί σημαντικό παράγοντα του ξενιστή για την αιτιολογία της νόσου. Δεδομένα από πειραματικά μοντέλα κολίτιδας έχουν βοηθήσει σημαντικά στην κατανόηση των ανοσολογικών μηχανισμών που εμπλέκονται στην έναρξη και την εξέλιξη της νόσου. Συνολικά, φαίνεται ότι μία διαταραχή στο ανοσολογικό σύστημα του εντερικού βλεννογόνου οδηγεί σε υπερπαραγωγή φλεγμονωδών κυτταροκινών, απελευθέρωση μεσολαβητών οξειδωτικού στρες και διήθηση του εντέρου από φλεγμονώδη κύτταρα με αποτέλεσμα φλεγμονή του εντέρου και ιστική καταστροφή. Τα κατασταλτικά κύτταρα μυελικής προέλευσης (Myeoid-derived suppressor cells- MDSCs) αποτελούν έναν ετερογενή πληθυσμό κυττάρων που περιλαμβάνει μακροφάγα, κοκκιοκύτταρα, δενδριτικά κύτταρα και κύτταρα μυελικής σειράς σε πρώιμα στάδια διαφοροποίησης. Στα ποντίκια, τα MDSCs χαρακτηρίζονται από την έκφραση των Gr-1 και CD11b δεικτών και περιλαμβάνουν δύο υποομάδες κυττάρων: αυτά με μορφολογία παρόμοια με εκείνη των κοκκιοκυττάρων και φαινότυπο CD11b+Ly6G+Ly6Clow και αυτά με μορφολογία παρόμοια με εκείνα των μονοκυττάρων και φαινότυπο CD11b+Ly6GlowLy6C+. Στους ανθρώπους, ο φαινοτυπικός προσδιορισμός των MDSCs συνιστά πρόκληση, λόγω της έλλειψης ενιαίων κριτηρίων. Συνηθέστερα, χαρακτηρίζονται απο την έκφραση του δείκτη CD33 της μυελικής σειράς και την έλλειψη έκφρασης τόσο του μορίου τάξης ΙΙ του μείζονος συμπλέγματος ιστοσυμβατότητας (MHC-ΙΙ), HLA-DR, όσο και άλλων δεικτών που χαρακτηρίζουν τις υπόλοιπες κυτταρικές σειρές του μυελού των οστών. Αν και ο ρόλος των MDSCs έχει κυρίως μελετηθεί σε πειραματικά μοντέλα καιασθενείς με καρκίνο, πρόσφατες μελέτες αναδεικνύουν το ρόλο αυτών σε πληθώρα παθολογικών καταστάσεων, όπως οι λοιμώξεις, η μεταμόσχευση και η αυτοανοσία. Παραδοσιακά, τα εν λόγω κύτταρα θεωρείται ότι καταστέλλουν την ανοσιακή απάντηση μέσω ποικίλων μηχανισμών. Ωστόσο, η πρόσφατη βιβλιογραφία επισημαίνει την πλαστικότητα αυτών των κυττάρων, δεδομένου ότι το εκάστοτε φλεγμονώδες περιβάλλον μπορεί να τους προσδώσει προφλεγμονώδεις ιδιότητες. Αν και οι κατασταλτικές ιδιότητες των MDSCs στις διαμεσολαβούμενες απο Τ κύτταρα ανοσιακές απαντήσεις είναι καλώς καθορισμένες, ο ρόλος αυτών στα αυτοάνοσα νοσήματα, όπως οι ΙΦΝΕ, είναι αμφιλεγόμενος. Πιο συγκεκριμένα, η ανοσοκατασταλτική δράση των MDSCs υποστηρίζεται από πολλές εργασίες που αναδεικνύουν την αύξηση των CD11b+Gr1+ MDSCs σε πειραματικά μοντέλα κολίτιδας. Παρομοίως, αύξηση των κατασταλτικών CD14+HLA-DRlow MDSCs περιγράφεται και στο περιφερικό αίμα ασθενών με ΙΦΝΕ. Ωστόσο, πρόσφατες μελέτες επισημαίνουν τον προφλεγμονώδη ρόλο των κυττάρων της μυελικής σειράς σε πειραματικά μοντέλα κολίτιδας, καθώς αυτόλογη μεταφορά Ly6Chigh κυττάρων εντερικού βλεννογόνου οδηγεί σε διαφοροποίηση των τελευταίων σε κύτταρα που προάγουν τη φλεγμονή του εντέρου. Στην παρούσα διδακτορική διατριβή, το ενδιαφέρον εστιάστηκε στον ανοσορυθμιστικό ρόλο των MDSCs σε πειραματικά μοντέλα κολίτιδας, καθώς και στις ανοσιακές απαντήσεις που διαμεσολαβούνται από τα Τ κύτταρα σε ασθενείς με ΙΦΝΕ. Ο αριθμός των MDSCs (ταυτοποιούμενα ως CD14+HLA-DR-/lowCD33+CD15+ κύτταρα) προσδιορίστηκε στο περιφερικό αίμα ασθενών με ΙΦΝΕ, ενώ η δράση αυτών αξιολογήθηκε με in vitro δοκιμασίες. Το πειραματικό μοντέλο που χρησιμοποιήθηκε ήταν αυτό της χημικά 2,4,6-trinitrobenzene sulfonic acid (TNBS) επαγόμενης κολίτιδας. Τα MDSCs χαρακτηρίστηκαν με τη μέθοδο της κυτταρομετρία ροής. Η in vivo ανοσοκατασταλτική δράση των MDSCs που καλλιεργήθηκαν από μυελό των οστών υγιών ποντικιών (BM-MDSCs) ελέγχθηκε τόσο με δοκιμασίες απαλοιφής όσο και αυτόλογης μεταφοράς. Η μελέτη σε ανθρώπινα δείγματα ασθενών με ΙΦΝΕ, ανέδειξε αύξηση του αριθμού των MDSCs στο περιφερικό αίμα ασθενών με ενεργό νόσο. Παρομοίως, τα MDSCs, ιδιαίτερα ο υποπληθυσμός που χαρακτηρίζεται ως Ly6G+, αυξήθηκε στα περιφερικά λεμφικά όργανα ποντικών με TNBS επαγόμενη κολίτιδα κατά την ενεργό φάση της νόσου. Αντίθετα με τις αρχικές προσδοκίες, η αυτόλογη μεταφορά BM-MDSCs σε ποντίκια με TNBS κολίτιδα απέτυχε να ελέγξει τη φλεγμονή in vivo. Περαιτέρω μελέτη του μηχανισμού δράσης των MDSCs, έδειξε ότι η έκθεση των εν λόγω κυττάρων στο φλεγμονώδες περιβάλλον της κολίτιδας οδηγεί σε αλλαγή του φαινότυπου (μείωση των Gr1high και αύξηση των Gr1low κυττάρων) αυτών, καθώς και σε μειωμένη έκφραση της πρωτεΐνης CCAAT/enhancer-binding protein beta (CEBPβ), η οποία αποτελεί μεταγραφικό παράγοντα κλειδί στην ανοσοκατασταλτική δράση των MDSCs. Σε συμφωνία με τα αποτελέσματα της μελέτης στο πειραματικό μοντέλο κολίτιδας, MDSCs τα οποία απομονώθηκαν από περιφερικό αίμα ασθενών με ενεργό νόσο όχι μόνο δεν κατέστειλαν αλλά αντιθέτως ενίσχυσαν τον πολλαπλασιασμό αυτόλογων CD4+ Τ κυττάρων ex vivo. Συνολικά, τα δεδομένα αυτά αναδεικνύουν μια παράδοξη λειτουργία των MDSCs σε πειραματικά μοντέλα κολίτιδας, καθώς και στην in vitro ανοσιακή απάντηση ασθενών με ΙΦΝΕ. Η περαιτέρω κατανόηση των μηχανισμών που οδηγούν στην απώλεια του βασικού χαρακτηριστικού των MDSCs, που συνίσταται στην καταστολή των ανοσιακών απαντήσεων, θα μπορούσε να υποβοηθήσει στο σχεδιασμό νέων θεραπευτικών στόχων.

scholarly journals CDDO induces granulocytic differentiation of myeloid leukemic blasts through translational up-regulation of p42 CCAAT enhancer–binding protein alpha

Blood ◽  
2007 ◽  
Vol 110 (10) ◽  
pp. 3695-3705 ◽  
Author(s):  
Steffen Koschmieder ◽  
Francesco D'Alò ◽  
Hanna Radomska ◽  
Christine Schöneich ◽  
Ji Suk Chang ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Myeloid Leukemia ◽  
De Novo ◽  
Binding Protein ◽  
Upstream Open Reading Frame ◽  
Dependent Manner ◽  
Granulocytic Differentiation ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Acute Myeloid

Abstract 2-Cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO) induces differentiation and apoptosis of tumor cells in vitro and in vivo. Here we assessed the effects of CDDO on CCAAT enhancer–binding protein alpha (CEBPA), a transcription factor critical for granulocytic differentiation. In HL60 acute myeloid leukemia (AML) cells, CDDO (0.01 to 2 μM) induces apoptosis in a dose-dependent manner. Conversely, subapoptotic doses of CDDO promote phagocytic activity and granulocytic-monocytic differentiation of HL60 cells through increased de novo synthesis of p42 CEBPA protein. CEBPA translational up-regulation is required for CDDO-induced granulocytic differentiation and depends on the integrity of the CEBPA upstream open reading frame (uORF). Moreover, CDDO increases the ratio of transcriptionally active p42 and the inactive p30 CEBPA isoform, which, in turn, leads to transcriptional activation of CEBPA-regulated genes (eg, GSCFR) and is associated with dephosphorylation of eIF2α and phosphorylation of eIF4E. In concordance with these results, CDDO induces a CEBPA ratio change and differentiation of primary blasts from patients with acute myeloid leukemia (AML). Because AML is characterized by arrested differentiation, our data suggest the inclusion of CDDO in the therapy of AML characterized by dysfunctional CEBPA expression.

scholarly journals EXTH-51. ANTI-INVASIVE EFFICACY AND SURVIVAL BENEFIT OF THE YAP-TEAD INHIBITOR VERTEPORFIN IN PRECLINICAL GLIOBLASTOMA MODELS

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii98-ii98
Author(s):  
Anne Marie Barrette ◽  
Alexandros Bouras ◽  
German Nudelman ◽  
Zarmeen Mussa ◽  
Elena Zaslavsky ◽  
...  
Keyword(s):  
Survival Benefit ◽  
De Novo ◽  
Epithelial Mesenchymal Transition ◽  
Intraperitoneal Administration ◽  
Standard Of Care ◽  
Tumor Burden ◽  
Mesenchymal Transition ◽  
Protein Levels

Abstract Glioblastoma (GBM) remains an incurable disease, in large part due to its malignant infiltrative spread, and current clinical therapy fails to target the invasive nature of tumor cells in disease progression and recurrence. Here, we use the YAP-TEAD inhibitor Verteporfin to target a convergence point for regulating tumor invasion/metastasis and establish the robust anti-invasive therapeutic efficacy of this FDA-approved drug and its survival benefit across several preclinical glioma models. Using patient-derived GBM cells and orthotopic xenograft models (PDX), we show that Verteporfin treatment disrupts YAP/TAZ-TEAD activity and processes related to cell adhesion, migration and epithelial-mesenchymal transition. In-vitro, Verteporfin impairs tumor migration, invasion and motility dynamics. In-vivo, intraperitoneal administration of Verteporfin in mice with orthotopic PDX tumors shows consistent drug accumulation within the brain and decreased infiltrative tumor burden, across three independent experiments. Interestingly, PDX tumors with impaired invasion after Verteporfin treatment downregulate CDH2 and ITGB1 adhesion protein levels within the tumor microenvironment. Finally, Verteporfin treatment confers survival benefit in two independent PDX models: as monotherapy in de-novo GBM and in combination with standard-of-care chemoradiation in recurrent GBM. These findings indicate potential therapeutic value of this FDA-approved drug if repurposed for GBM patients.

Granulocyte colony-stimulating factor regulates myeloid differentiation through CCAAT/enhancer-binding protein ε

Blood ◽  
2001 ◽  
Vol 98 (4) ◽  
pp. 897-905 ◽  
Author(s):  
Hideaki Nakajima ◽  
James N. Ihle
Keyword(s):  
Molecular Mechanisms ◽  
Binding Protein ◽  
Hematopoietic Cells ◽  
Myeloid Differentiation ◽  
Granulocyte Colony Stimulating Factor ◽  
Colony Stimulating Factor ◽  
Granulocytic Differentiation ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Stimulating Factor

Granulocyte colony-stimulating factor (G-CSF) is a major cytokine that regulates proliferation and differentiation of myeloid cells, although the underlying mechanisms by which G-CSF controls myeloid differentiation are largely unknown. Differentiation of hematopoietic cells is regulated by lineage-specific transcription factors, and gene-targeting studies previously revealed the critical roles of CCAAT/enhancer-binding protein (C/EBP) α and C/EBPε, respectively, in the early and mid-late stages of granulocyte differentiation. The expression of C/EBPε in 32Dcl3 cells and FDCP1 cells expressing mutant G-CSF receptors was examined and it was found that G-CSF up-regulates C/EBPε. The signal for this expression required the region containing the first tyrosine residue of G-CSF receptor. Dominant-negative signal transducers and activators of transcription 3 blocked G-CSF–induced granulocytic differentiation in 32D cells but did not block induction of C/EBPε, indicating that these proteins work in different pathways. It was also found that overexpression of C/EBPε greatly facilitated granulocytic differentiation by G-CSF and, surprisingly, that expression of C/EBPε alone was sufficient to make cells differentiate into morphologically and functionally mature granulocytes. Overexpression of c-myc inhibits differentiation of hematopoietic cells, but the molecular mechanisms of this inhibition are not fully understood. In 32Dcl3 cells overexpressing c-myc that do not differentiate by means of G-CSF, induction of C/EBPε is completely abrogated. Ectopic expression of C/EBPε in these cells induced features of differentiation, including changes in nuclear morphologic characteristics and the appearance of granules. These data show that C/EBPε constitutes a rate-limiting step in G-CSF–regulated granulocyte differentiation and that c-myc antagonizes G-CSF–induced myeloid differentiation, at least partly by suppressing induction of C/EBPε.

Tumor necrosis factor-α upregulates 11β-hydroxysteroid dehydrogenase type 1 expression by CCAAT/enhancer binding protein-β in HepG2 cells

2009 ◽  
Vol 296 (2) ◽  
pp. E367-E377 ◽  
Author(s):  
Irena D. Ignatova ◽  
Radina M. Kostadinova ◽  
Christopher E. Goldring ◽  
Andrea R. Nawrocki ◽  
Felix J. Frey ◽  
...  
Keyword(s):  
P38 Mapk ◽  
Hepg2 Cells ◽  
Binding Protein ◽  
Hydroxysteroid Dehydrogenase ◽  
Expression Vectors ◽  
Enhancer Binding Protein ◽  
Tnf Α ◽  
Ccaat Enhancer Binding Protein

The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) catalyzes the conversion of inactive to active glucocorticoids. 11β-HSD1 plays a crucial role in the pathogenesis of obesity and controls glucocorticoid actions in inflammation. Several studies have demonstrated that TNF-α increases 11β-HSD1 mRNA and activity in various cell models. Here, we demonstrate that mRNA and activity of 11β-HSD1 is increased in liver tissue from transgenic mice overexpressing TNF-α, indicating that this effect also occurs in vivo. To dissect the molecular mechanism of this increase, we investigated basal and TNF-α-induced transcription of the 11β-HSD1 gene ( HSD11B1) in HepG2 cells. We found that TNF-α acts via p38 MAPK pathway. Transient transfections with variable lengths of human HSD11B1 promoter revealed highest activity with or without TNF-α in the proximal promoter region (−180 to +74). Cotransfection with human CCAAT/enhancer binding protein-α (C/EBPα) and C/EBPβ-LAP expression vectors activated the HSD11B1 promoter with the strongest effect within the same region. Gel shift and RNA interference assays revealed the involvement of mainly C/EBPα, but also C/EBPβ, in basal and only of C/EBPβ in the TNF-α-induced HSD11B1 expression. Chromatin immunoprecipitation assay confirmed in vivo the increased abundance of C/EBPβ on the proximal HSD11B1 promoter upon TNF-α treatment. In conclusion, C/EBPα and C/EBPβ control basal transcription, and TNF-α upregulates 11β-HSD1, most likely by p38 MAPK-mediated increased binding of C/EBPβ to the human HSD11B1 promoter. To our knowledge, this is the first study showing involvement of p38 MAPK in the TNF-α-mediated 11β-HSD1 regulation, and that TNF-α stimulates enzyme activity in vivo.

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