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9 results on '"Johnson, Jolyn"'

3. Protein kinase C: a key regulator of dendritic cell function

Author

Johnson, Jolyn, Goldman, Michel, Willems, Fabienne, Bergmann, Pierre, Leo, Oberdan, Trottein, François, Bruyns, Catherine, Communi, Didier, Erneux, Christophe, and Trottein, Francois

Subjects
Interleukines, Protein kinase C, Réaction immunitaire, Interleukins, Cellules dendritiques, Cytokines, Disciplines biomédicales diverses, dendritic cells, Immune response, Protéine kinase C
Abstract

The innate immune system is an important mechanism that protects the host from infection. Viral and bacterial infection triggers activation of the transcription factors interferon response factor (IRF) 3 and nuclear factor (NF)-kB. These transcription factors collaborate to induce transcription of type I interferons (IFNs) cytokines and the interleukin (IL)-12 family of cytokines. Type I IFN and the IL-12 family of cytokines play a critical role in establishing innate immune responses as well as initiating and directing adaptive responses. Our study focused on the role of protein kinase C (PKC) isoforms in Toll-like (TLR)-dependent and –independent activation of IRF-3 and NF-kB and their subsequent regulation of IFN-beta and the IL-12 family of cytokines. TLR3, TLR4 and retinoic acid-inducible gene 1 (RIG-1)/melanoma differentiation associated gene 5 (MDA-5) activation by double stranded (ds) RNA mimic polyinosine-polycytidylic acid (poly(I:C)), lipopolysaccharide (LPS) and synthetic ds-B-DNA respectively, mediated IFN-beta as well as TNF-alpha and IL-8 synthesis in monocyte-derived DCs. Using the pharmacological inhibitor of conventional PKCs (cPKCs), Gö6976, we demonstrated that this family of kinases was involved in TLR3, TLR4 and RIG-1/ MDA-5 signaling pathways leading to the production of IFN-beta but not of TNF-alpha and IL-8. Further analysis with the use of specific kinase inactive cPKC isoforms and siRNA targeted to PKCalpha, we established that PKCalpha was the isoform involved in the TLR3 signaling pathway. In the case of TLR3, we show that PKCalphaexerts its effect downstream of TRIF and TBK1. Moreover, we show that inactivation of PKCalpha specifically inhibits the activation of IRF-3 and not that of NF-kB. Through biochemical analysis, we assessed the contribution of PKCalpha in the critical events of IRF-3 activation: a) phosphorylation b) homodimerization c) nuclear translocation d) DNA-binding and e) recruitment of creb-binding protein (CBP). We conclude that inhibition of cPKCs severely hinders the association of IRF-3 with CBP. Overall, these data revealed the critical role of cPKCs in TLR-dependent and -independent pathways leading to IFN-beta synthesis. The selective targeting of IRF-3 by cPKCs prompted us to study the possible implications of cPKCs in the transcriptional control of IL-12 family members, some of which are regulated by IRF3. Indeed, recent studies have emerged demonstrating the essential role of IRF-3 in IL-12p35 and IL-27p28 gene expression (1;2). Likewise, we investigated the role of cPKCs in the regulation of LPS- and poly(I:C)-induced expression of IL-12(p40/p35), IL-23(p40/p19) and IL-27(p28/EBI3) in monocyte-derived DCs. Treatment of monocyte-derived DCs with Gö6976 down-regulated LPS- and poly(I:C)-induced IL-12 and IL-27 synthesis while it did not alter IL-23 production. Next, we showed that impaired IL-12 and IL-27 synthesis was due to repressed IL-12p35 and IL-27p28 gene expression downstream of TLR3 and TLR4 whereas IL-23p19 and IL-27EBI3 gene expression were not modified. Reporter gene assays demonstrated that cPKCs are involved in LPS- and poly(I:C)-induced IL-12p35 and IL-27p28 promoter activity. Finally, experiments in bone marrow-derived DCs from IRF-3-/- and wild type mice showed that IL-23 synthesis does not require IRF-3 activation. We conclude that cPKCs through the control of IRF-3 activity are critically involved in the regulation of IL-12 and IL-27 synthesis downstream of TLR3 and TLR4 while they do not participate in IRF-3-independent IL-23 synthesis. On whole, we demonstrated a novel function for cPKCs in the regulation of IRF-3 and IRF-3 dependent gene expression, specifically IFN-beta, IL-12 and IL-27. In light of the important and divergent roles of IFN-beta and IL-12 family of cytokines on the development of T helper (Th) Th1, Th2, Th17-mediated immune responses, cPKCs represent a potential target for therapeutic immunomodulation. This modulation needs to be carefully administered due to the complex interplay of the IL-12 family members in immunity., Doctorat en sciences biomédicales, info:eu-repo/semantics/published

Published
2007

4. PKC-alpha controls MYD88-dependent TLR/IL-1R signaling and cytokine production in mouse and human dendritic cells.

Author

Langlet, Christelle, Springael, Cécile, Johnson, Jolyn, Thomas, Séverine, Flamand, Véronique, Leitges, Michael, Goldman, Michel, Aksoy, Ezra, Willems, Fabienne, Langlet, Christelle, Springael, Cécile, Johnson, Jolyn, Thomas, Séverine, Flamand, Véronique, Leitges, Michael, Goldman, Michel, Aksoy, Ezra, and Willems, Fabienne

Abstract

Conventional PKC (cPKC)-alpha regulates TRIF-dependent IFN response factor 3 (IRF3)-mediated gene transcription, but its role in MyD88-dependent TLR signaling remains unknown. Herein, we demonstrate that PKC-alpha is induced by several MyD88-dependent TLR/IL-1R ligands and regulates cytokine expression in human and murine DC. First, inhibition of cPKC activity in human DC by cPKC-specific inhibitors, Gö6976 or HBDDe, downregulated the production of classical inflammatory/immunomodulatory cytokines induced by TLR2, TLR5 or IL-1R but not by TLR3 stimulation. Similarly, dominant negative PKC-alpha repressed Pam(3)CSK(4) induced NF-kappaB- and AP-1-driven promoter activities in TLR2-expressing human embryonic kidney 293 T cells. Dominant negative PKC-alpha inhibited NF-kappaB reporter activity mediated by overexpression of MyD88 but not TRIF. Unexpectedly, BM-derived DC from PKC-alpha(-/-) mice exhibited decreased TNF-alpha and IL-12p40 production induced by both MyD88- and TRIF-dependent ligands. Furthermore, PKC-alpha is coupled to TLR2 signaling proximal to MyD88 since MAPK and IkappaB kinase-alpha/beta phosphorylations and IkappaBalpha degradation were inhibited in PKC-alpha(-/-) BM-derived DC. Finally, co-immunoprecipitation assays revealed that PKC-alpha physically interacts with Pam(3)CSK(4) activated TLR2 in WT but not in MyD88(-/-) DC. Collectively this study identifies a species-specific role of PKC-alpha as a key component that controls MyD88-dependent cytokine gene expression in human and mouse but differentially regulates production of TRIF-dependent cytokines., Journal Article, Research Support, Non-U.S. Gov't, FLWIN, info:eu-repo/semantics/published

Published
2010

5. Protein kinase C: a key regulator of dendritic cell function

Author

Goldman, Michel, Willems, Fabienne, Bergmann, Pierre, Leo, Oberdan, Trottein, François, Bruyns, Catherine, Communi, Didier, Erneux, Christophe, Johnson, Jolyn, Goldman, Michel, Willems, Fabienne, Bergmann, Pierre, Leo, Oberdan, Trottein, François, Bruyns, Catherine, Communi, Didier, Erneux, Christophe, and Johnson, Jolyn

Abstract

The innate immune system is an important mechanism that protects the host from infection. Viral and bacterial infection triggers activation of the transcription factors interferon response factor (IRF) 3 and nuclear factor (NF)-kB. These transcription factors collaborate to induce transcription of type I interferons (IFNs) cytokines and the interleukin (IL)-12 family of cytokines. Type I IFN and the IL-12 family of cytokines play a critical role in establishing innate immune responses as well as initiating and directing adaptive responses. Our study focused on the role of protein kinase C (PKC) isoforms in Toll-like (TLR)-dependent and –independent activation of IRF-3 and NF-kB and their subsequent regulation of IFN-beta and the IL-12 family of cytokines., Doctorat en sciences biomédicales, info:eu-repo/semantics/nonPublished

Published
2007

6. Protein kinase Calpha is involved in interferon regulatory factor 3 activation and type I interferon-beta synthesis.

Author

Johnson, Jolyn, Albarani, Valentina, Nguyen, Muriel, Goldman, Michel, Willems, Fabienne, Aksoy, Ezra, Johnson, Jolyn, Albarani, Valentina, Nguyen, Muriel, Goldman, Michel, Willems, Fabienne, and Aksoy, Ezra

Abstract

Protein kinase C (PKC) isoforms are critically involved in the regulation of innate immune responses. Herein, we investigated the role of conventional PKCalpha in the regulation of IFN-beta gene expression mediated by the Toll-like receptor 3 (TLR3) signaling pathway. Inhibition of conventional PKC (cPKC) activity in monocyte-derived dendritic cells or TLR3-expressing cells by an isoform-specific inhibitor, Gö6976, selectively inhibited IFN-beta synthesis induced by double-stranded RNA polyinosine-polycytidylic acid. Furthermore, reporter gene assays confirmed that PKCalpha regulates IFN-beta promoter activity, since overexpression of dominant negative PKCalpha but not PKCbeta(I) repressed interferon regulatory factor 3 (IRF-3)-dependent but not NF-kappaB-mediated promoter activity upon TLR3 engagement in HEK 293 cells. Dominant negative PKCalpha inhibited IRF-3 transcriptional activity mediated by overexpression of TIR domain-containing adapter inducing IFN-beta and Tank-binding kinase-1. Additional biochemical analysis demonstrated that Gö6976-treated dendritic cells exhibited IRF-3 phosphorylation, dimerization, nuclear translocation, and DNA binding activity analogous to their control counterparts in response to polyinosine-polycytidylic acid. In contrast, co-immunoprecipitation experiments revealed that TLR3-induced cPKC activity is essential for mediating the interaction of IRF-3 but not p65/RelA with the co-activator CREB-binding protein. Furthermore, PKCalpha knock-down with specific small interfering RNA inhibited IFN-beta expression and down-regulated IRF-3-dependent promoter activity, establishing PKCalpha as a component of TLR3 signaling that regulates IFN-beta gene expression by targeting IRF-3-CREB-binding protein interaction. Finally, we analyzed the involvement of cPKCs in other signaling pathways leading to IFN-beta synthesis. These experiments revealed that cPKCs play a role in the synthesis of IFN-beta induced via both TLR-dependent and -independe, Journal Article, Research Support, Non-U.S. Gov't, info:eu-repo/semantics/published

Published
2007

7. A concrete example: when the cracks begin to show

Author

Boon, Jean-Pierre, Castillo, José, Djerassi, C., Johnson, Jolyn, Lovett, A., Norretranders, T., Patera, V., Sommerer, C., Taylor, Robert L., Thurner, S., Boon, Jean-Pierre, Castillo, José, Djerassi, C., Johnson, Jolyn, Lovett, A., Norretranders, T., Patera, V., Sommerer, C., Taylor, Robert L., and Thurner, S.

Abstract

info:eu-repo/semantics/published

Published
2006

9. PKC-alpha controls MYD88-dependent TLR/IL-1R signaling and cytokine production in mouse and human dendritic cells.

Author

Langlet C, Springael C, Johnson J, Thomas S, Flamand V, Leitges M, Goldman M, Aksoy E, and Willems F

Subjects
Adaptor Proteins, Vesicular Transport genetics, Adaptor Proteins, Vesicular Transport metabolism, Animals, Carbazoles pharmacology, Cell Line, Cells, Cultured, Dendritic Cells cytology, Enzyme Inhibitors pharmacology, Humans, Immunoblotting, Intracellular Signaling Peptides and Proteins metabolism, Membrane Proteins metabolism, Mice, Mice, Inbred C57BL, Mice, Inbred Strains, Mice, Knockout, Mitogen-Activated Protein Kinases metabolism, Myeloid Differentiation Factor 88 genetics, Myristoylated Alanine-Rich C Kinase Substrate, NF-kappa B metabolism, Phosphorylation, Protein Kinase C antagonists & inhibitors, Receptors, Interleukin-1 genetics, Reverse Transcriptase Polymerase Chain Reaction, Toll-Like Receptors genetics, Transcription Factor AP-1 metabolism, Cytokines metabolism, Dendritic Cells metabolism, Myeloid Differentiation Factor 88 metabolism, Protein Kinase C metabolism, Receptors, Interleukin-1 metabolism, Toll-Like Receptors metabolism
Abstract

Conventional PKC (cPKC)-alpha regulates TRIF-dependent IFN response factor 3 (IRF3)-mediated gene transcription, but its role in MyD88-dependent TLR signaling remains unknown. Herein, we demonstrate that PKC-alpha is induced by several MyD88-dependent TLR/IL-1R ligands and regulates cytokine expression in human and murine DC. First, inhibition of cPKC activity in human DC by cPKC-specific inhibitors, Gö6976 or HBDDe, downregulated the production of classical inflammatory/immunomodulatory cytokines induced by TLR2, TLR5 or IL-1R but not by TLR3 stimulation. Similarly, dominant negative PKC-alpha repressed Pam(3)CSK(4) induced NF-kappaB- and AP-1-driven promoter activities in TLR2-expressing human embryonic kidney 293 T cells. Dominant negative PKC-alpha inhibited NF-kappaB reporter activity mediated by overexpression of MyD88 but not TRIF. Unexpectedly, BM-derived DC from PKC-alpha(-/-) mice exhibited decreased TNF-alpha and IL-12p40 production induced by both MyD88- and TRIF-dependent ligands. Furthermore, PKC-alpha is coupled to TLR2 signaling proximal to MyD88 since MAPK and IkappaB kinase-alpha/beta phosphorylations and IkappaBalpha degradation were inhibited in PKC-alpha(-/-) BM-derived DC. Finally, co-immunoprecipitation assays revealed that PKC-alpha physically interacts with Pam(3)CSK(4) activated TLR2 in WT but not in MyD88(-/-) DC. Collectively this study identifies a species-specific role of PKC-alpha as a key component that controls MyD88-dependent cytokine gene expression in human and mouse but differentially regulates production of TRIF-dependent cytokines.

Published
2010
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