Guillaume GIRAUD
@ihu-hepatolyon.fr
INSERM UMR1350
Scopus Publications
- Role of cccDNA in the Quest for HBV Cure- Implications for HIV-HBV Coinfection
Guillaume Giraud, Barbara Testoni
Current HIV AIDS Reports, 2025 - Protocol for isolating CD163+ Kupffer cells from human liver resections
Armando Andres Roca Suarez, Marie-Laure Plissonnier, Maud Michelet, Anaëlle Dubois, Sarah Heintz, Maria Saez-Palma, Marion Delphin, Isabelle Bordes, Jennifer Molle, Audrey Diederichs, Mélanie Rodà, Emmanuel Combe, Léa Mougené, Guillaume Giraud, Xavier Grand, Michel Rivoire, Massimo Levrero, Barbara Testoni, Fabien Zoulim
STAR Protocols, 2024
The liver microenvironment contains a wide variety of monocyte and macrophage populations. Here, we present a protocol for the specific isolation of liver-resident macrophages, known as Kupffer cells (KCs), from human liver resections. We describe steps for dissociating human liver tissues, separating non-parenchymal cells into fractions by a 2-phase iodixanol gradient, and positive selection of KCs based on the expression of CD163. We then provide instructions for validating the procedure by immunofluorescence to detect CD163. For complete details on the use and execution of this protocol, please refer to Roca Suarez, Plissonnier, et al. 1 • Protocol for the isolation of human Kupffer cells (KCs) • Validation of the procedure by IF detection of CD163 • Isolated KCs are suitable for functional and perturbation studies • Liver dissociation technique is compatible with the isolation of additional cell types Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics. The liver microenvironment contains a wide variety of monocyte and macrophage populations. Here, we present a protocol for the specific isolation of liver-resident macrophages, known as Kupffer cells (KCs), from human liver resections. We describe steps for dissociating human liver tissues, separating non-parenchymal cells into fractions by a 2-phase iodixanol gradient, and positive selection of KCs based on the expression of CD163. We then provide instructions for validating the procedure by immunofluorescence to detect CD163. - TLR8 agonist selgantolimod regulates Kupffer cell differentiation status and impairs HBV entry into hepatocytes via an IL-6-dependent mechanism
Armando Andres Roca Suarez, Marie-Laure Plissonnier, Xavier Grand, Maud Michelet, Guillaume Giraud, Maria Saez-Palma, Anaëlle Dubois, Sarah Heintz, Audrey Diederichs, Nicolaas Van Renne, Thomas Vanwolleghem, Stephane Daffis, Li Li, Nikita Kolhatkar, Yao-Chun Hsu, Jeffrey J Wallin, Audrey H Lau, Simon P Fletcher, Michel Rivoire, Massimo Levrero, Barbara Testoni, Fabien Zoulim
Gut, 2024
ObjectiveAchieving HBV cure will require novel combination therapies of direct-acting antivirals and immunomodulatory agents. In this context, the toll-like receptor 8 (TLR8) agonist selgantolimod (SLGN) has been investigated in preclinical models and clinical trials for chronic hepatitis B (CHB). However, little is known regarding its action on immune effectors within the liver. Our aim was to characterise the transcriptomic changes and intercellular communication events induced by SLGN in the hepatic microenvironment.DesignWe identifiedTLR8-expressing cell types in the human liver using publicly available single-cell RNA-seq data and established a method to isolate Kupffer cells (KCs). We characterised transcriptomic and cytokine KC profiles in response to SLGN. SLGN’s indirect effect was evaluated by RNA-seq in hepatocytes treated with SLGN-conditioned media (CM) and quantification of HBV parameters following infection. Pathways mediating SLGN’s effect were validated using transcriptomic data from HBV-infected patients.ResultsHepaticTLR8expression takes place in the myeloid compartment. SLGN treatment of KCs upregulated monocyte markers (eg,S100A12) and downregulated genes associated with the KC identity (eg,SPIC). Treatment of hepatocytes with SLGN-CM downregulatedNTCPand impaired HBV entry. Cotreatment with an interleukin 6-neutralising antibody reverted the HBV entry inhibition.ConclusionOur transcriptomic characterisation of SLGN sheds light into the programmes regulating KC activation. Furthermore, in addition to its previously described effect on established HBV infection and adaptive immunity, we show that SLGN impairs HBV entry. Altogether, SLGN may contribute through KCs to remodelling the intrahepatic immune microenvironment and may thus represent an important component of future combinations to cure HBV infection. - Helicases DDX5 and DDX17 promote heterogeneity in HBV transcription termination in infected human hepatocytes
Fleur Chapus, Guillaume Giraud, Pélagie Huchon, Mélanie Rodà, Xavier Grand, Caroline Charre, Chloé Goldsmith, Armando Andres Roca Suarez, Maria-Guadalupe Martinez, Judith Fresquet, Audrey Diederichs, Maëlle Locatelli, Hélène Polvèche, Caroline Scholtès, Isabelle Chemin, Hector Hernandez Vargas, Michel Rivoire, Cyril F. Bourgeois, Fabien Zoulim, Barbara Testoni
Journal of Hepatology, 2024 - cccDNA phase separates in a G-quadruplex-dependent manner to facilitate its transcription and HBV replication
Guillaume Giraud, Barbara Testoni
Medecine Sciences, 2024
International audience - Co-Transcriptional Regulation of HBV Replication: RNA Quality Also Matters
Guillaume Giraud, Khadija El Achi, Fabien Zoulim, Barbara Testoni
Viruses, 2024
Chronic hepatitis B (CHB) virus infection is a major public health burden and the leading cause of hepatocellular carcinoma. Despite the efficacy of current treatments, hepatitis B virus (HBV) cannot be fully eradicated due to the persistence of its minichromosome, or covalently closed circular DNA (cccDNA). The HBV community is investing large human and financial resources to develop new therapeutic strategies that either silence or ideally degrade cccDNA, to cure HBV completely or functionally. cccDNA transcription is considered to be the key step for HBV replication. Transcription not only influences the levels of viral RNA produced, but also directly impacts their quality, generating multiple variants. Growing evidence advocates for the role of the co-transcriptional regulation of HBV RNAs during CHB and viral replication, paving the way for the development of novel therapies targeting these processes. This review focuses on the mechanisms controlling the different co-transcriptional processes that HBV RNAs undergo, and their contribution to both viral replication and HBV-induced liver pathogenesis. - G-quadruplexes control hepatitis B virus replication by promoting cccDNA transcription and phase separation in hepatocytes
Guillaume Giraud, Mélanie Rodà, Pélagie Huchon, Maud Michelet, Sarah Maadadi, Daniel Jutzi, Roland Montserret, Marc-David Ruepp, Romain Parent, Christophe Combet, Fabien Zoulim, Barbara Testoni
Nucleic Acids Research, 2024
Phase separation regulates fundamental processes in gene expression and is mediated by the local concentration of proteins and nucleic acids, as well as nucleic acid secondary structures such as G-quadruplexes (G4s). These structures play fundamental roles in both host gene expression and in viral replication due to their peculiar localisation in regulatory sequences. Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) is an episomal minichromosome whose persistence is at the basis of chronic infection. Identifying the mechanisms controlling its transcriptional activity is indispensable to develop new therapeutic strategies against chronic hepatitis B. The aim of this study was to determine whether G4s are formed in cccDNA and regulate viral replication. Combining biochemistry and functional studies, we demonstrate that cccDNA indeed contains ten G4s structures. Furthermore, mutations disrupting two G4s located in the enhancer I HBV regulatory region altered cccDNA transcription and viral replication. Finally, we showed for the first time that cccDNA undergoes phase separation in a G4-dependent manner to promote its transcription in infected hepatocytes. Altogether, our data give new insight in the transcriptional regulation of the HBV minichromosome that might pave the way for the identification of novel targets to destabilize or silence cccDNA. - Detection and Quantification of HBV Transcripts by Full-Length 5′RACE-PCR
Guillaume Giraud, Doohyun Kim, Bernd Stadelmayer, Fleur Chapus, Barbara Testoni, Fabien Zoulim
Methods in Molecular Biology, 2024 - RNA helicase-dependent gene looping impacts messenger RNA processing
Sophie Terrone, Jessica Valat, Nicolas Fontrodona, Guillaume Giraud, Jean-Baptiste Claude, Emmanuel Combe, Audrey Lapendry, Hélène Polvèche, Lamya Ben Ameur, Arnaud Duvermy, Laurent Modolo, Pascal Bernard, Franck Mortreux, Didier Auboeuf, Cyril F Bourgeois
Nucleic Acids Research, 2022
DDX5 and DDX17 are DEAD-box RNA helicase paralogs which regulate several aspects of gene expression, especially transcription and splicing, through incompletely understood mechanisms. A transcriptome analysis of DDX5/DDX17-depleted human cells confirmed the large impact of these RNA helicases on splicing and revealed a widespread deregulation of 3′ end processing. In silico analyses and experiments in cultured cells showed the binding and functional contribution of the genome organizing factor CTCF to chromatin sites at or near a subset of DDX5/DDX17-dependent exons that are characterized by a high GC content and a high density of RNA Polymerase II. We propose the existence of an RNA helicase-dependent relationship between CTCF and the dynamics of transcription across DNA and/or RNA structured regions, that contributes to the processing of internal and terminal exons. Moreover, local DDX5/DDX17-dependent chromatin loops spatially connect RNA helicase-regulated exons with their cognate promoter, and we provide the first direct evidence that de novo gene looping modifies alternative splicing and polyadenylation. Overall our findings uncover the impact of DDX5/DDX17-dependent chromatin folding on pre-messenger RNA processing. - Chromatin Conformation in Development and Disease
Ilias Boltsis, Frank Grosveld, Guillaume Giraud, Petros Kolovos
Frontiers in Cell and Developmental Biology, 2021
Chromatin domains and loops are important elements of chromatin structure and dynamics, but much remains to be learned about their exact biological role and nature. Topological associated domains and functional loops are key to gene expression and hold the answer to many questions regarding developmental decisions and diseases. Here, we discuss new findings, which have linked chromatin conformation with development, differentiation and diseases and hypothesized on various models while integrating all recent findings on how chromatin architecture affects gene expression during development, evolution and disease. - Interplay between FLI-1 and the LDB1 complex in murine erythroleukemia cells and during megakaryopoiesis
Guillaume Giraud, Petros Kolovos, Ilias Boltsis, Jente van Staalduinen, Boris Guyot, Michele Weiss-Gayet, Wilfred van IJcken, François Morlé, Frank Grosveld
Iscience, 2021 - The CCCTC-binding factor CTCF represses hepatitis B virus enhancer I and regulates viral transcription
Valentina D'Arienzo, Jack Ferguson, Guillaume Giraud, Fleur Chapus, James M. Harris, Peter A. C. Wing, Adam Claydon, Sophia Begum, Xiaodong Zhuang, Peter Balfe, Barbara Testoni, Jane A. McKeating, Joanna L. Parish
Cellular Microbiology, 2021 - Intragenic recruitment of NF-κB drives splicing modifications upon activation by the oncogene Tax of HTLV-1
Lamya Ben Ameur, Paul Marie, Morgan Thenoz, Guillaume Giraud, Emmanuel Combe, Jean-Baptiste Claude, Sebastien Lemaire, Nicolas Fontrodona, Hélène Polveche, Marine Bastien, Antoine Gessain, Eric Wattel, Cyril F. Bourgeois, Didier Auboeuf, Franck Mortreux
Nature Communications, 2020 - Functions of DEAD box RNA helicases DDX5 and DDX17 in chromatin organization and transcriptional regulation
Guillaume Giraud, Sophie Terrone, Cyril F. Bourgeois
Bmb Reports, 2018 - The RNA helicase DDX17 controls the transcriptional activity of REST and the expression of proneural microRNAs in neuronal differentiation
Marie-Pierre Lambert, Sophie Terrone, Guillaume Giraud, Clara Benoit-Pilven, David Cluet, Valérie Combaret, Franck Mortreux, Didier Auboeuf, Cyril F Bourgeois
Nucleic Acids Research, 2018 - NLS-tagging: an alternative strategy to tag nuclear proteins
Guillaume Giraud, Ralph Stadhouders, Andrea Conidi, Dick H.W. Dekkers, Danny Huylebroeck, Jeroen A.A. Demmers, Eric Soler, Frank G. Grosveld
Nucleic Acids Research, 2014 - Spi-1, Fli-1 and Fli-3 (miR-17-92) Oncogenes Contribute to a Single Oncogenic Network Controlling Cell Proliferation in Friend Erythroleukemia
Samer Kayali, Guillaume Giraud, François Morlé, Boris Guyot
Plos One, 2012 - Spi-1 and Fli-1 directly activate common target genes involved in ribosome biogenesis in friend erythroleukemic cells
Gaëtan Juban, Guillaume Giraud, Boris Guyot, Stéphane Belin, Jean-Jacques Diaz, Joëlle Starck, Christel Guillouf, Françoise Moreau-Gachelin, François Morlé
Molecular and Cellular Biology, 2009
