TY  - JOUR
AB  - Hepatitis B virus (HBV) infection is a major health threat causing 880,000 deaths each year. Available therapies control viral replication, but do not cure HBV leaving patients at risk to develop hepatocellular carcinoma. Here we show that HBV envelope proteins (HBs) - besides their integration into endosomal membranes - become embedded in the plasma membrane where they can be targeted by redirected T-cells. HBs was detected on the surface of HBV-infected cells, in livers of mice replicating HBV and in HBV-induced hepatocellular carcinoma. Staining with HBs-specific recombinant antibody MoMab recognizing a conformational epitope indicated that membrane-associated HBs remains correctly folded in HBV-replicating cells in cell culture and in livers of HBV-transgenic mice in vivo. MoMab coated onto superparamagnetic iron oxide nanoparticles allowed to detect membrane-associated HBs after HBV infection by electron microscopy in distinct stretches of the hepatocyte plasma membrane. Last not least we demonstrate that HBs located to the cell surface allows therapeutic targeting of HBV-positive cells by T-cells either engrafted with a chimeric antigen receptor or redirected by bispecific, T-cell engager antibodies. This article is protected by copyright. All rights reserved.
AU  - Zhao, L.
AU  - Chen, F.
AU  - Quitt, O.
AU  - Festag, M.
AU  - Ringelhan, M.*
AU  - Wisskirchen, K.
AU  - Festag, J.
AU  - Yakovleva, L.*
AU  - Sureau, C.*
AU  - Bohne, F.
AU  - Aichler, M.
AU  - Bruss, V.
AU  - Shevtsov, M.*
AU  - van de Klundert, M.
AU  - Momburg, F.*
AU  - Möhl, B.S.
AU  - Protzer, U.
C1  - 63419
C2  - 51526
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
TI  - Hepatitis B virus envelope proteins can serve as therapeutic targets embedded in the host cell plasma membrane.
JO  - Cell. Microbiol.
VL  - 23
IS  - 12
PB  - Wiley
PY  - 2021
SN  - 1462-5814
ER  - 

TY  - JOUR
AB  - Hepatitis B virus (HBV) is an enveloped DNA virus that contains a partially double-stranded relaxed circular (rc) DNA. Upon infection, rcDNA is delivered to the nucleus where it is repaired to covalently closed circular (ccc) DNA that serves as the transcription template for all viral RNAs. Our understanding of HBV particle entry dynamics and host pathways regulating intracellular virus trafficking and cccDNA formation is limited. The discovery of sodium taurocholate co-transporting peptide (NTCP) as the primary receptor allows studies on these early steps in viral life cycle. We employed a synchronised infection protocol to quantify HBV entry kinetics. HBV attachment to cells at 4 degrees C is independent of NTCP, however, subsequent particle uptake is NTCP-dependent and reaches saturation at 12 h post-infection. HBV uptake is clathrin- and dynamin dependent with actin and tubulin playing a role in the first 6 h of infection. Cellular fractionation studies demonstrate HBV DNA in the nucleus within 6 h of infection and cccDNA was first detected at 24 h post-infection. Our studies show the majority (83%) of cell bound particles enter HepG2-NTCP cells, however, only a minority (<1%) of intracellular rcDNA was converted to cccDNA, highlighting this as a rate-limiting in establishing infection in vitro. This knowledge highlights the deficiencies in our in vitro cell culture systems and will inform the design and evaluation of physiologically relevant models that support efficient HBV replication.
AU  - Chakraborty, A.
AU  - Ko, C.
AU  - Henning, C.
AU  - Lucko, A.
AU  - Harris, J.M.*
AU  - Chen, F.*
AU  - Zhuang, X.*
AU  - Wettengel, J.M.
AU  - Roessler, S.*
AU  - Protzer, U.
AU  - McKeating, J.A.*
C1  - 59916
C2  - 49116
CY  - 111 River St, Hoboken 07030-5774, Nj Usa
TI  - Synchronised infection identifies early rate-limiting steps in the hepatitis B virus life cycle.
JO  - Cell. Microbiol.
VL  - 22
IS  - 12
PB  - Wiley
PY  - 2020
SN  - 1462-5814
ER  - 

TY  - JOUR
AB  - Members of the NLR family evolved as intracellular sensors for bacterial and viral infection. However, our knowledge on the implication of most of the human NLR proteins in innate immune responses still remains fragmentary. Here we characterized the role of human NLRP10 in bacterial infection. Our data revealed that NLRP10 is a cytoplasmic localized protein that positively contributes to innate immune responses induced by the invasive bacterial pathogen Shigella flexneri. SiRNA-mediated knock-down studies showed that NLRP10 contributes to pro-inflammatory cytokine release triggered by Shigella in epithelial cells and primary dermal fibroblasts, by influencing p38 and NF-κB activation. This effect is dependent on the ATPase activity of NLRP10 and its PYD domain. Mechanistically, NLRP10 interacts with NOD1, a NLR that is pivotally involved in sensing of invasive microbes, and both proteins are recruited to the bacterial entry point at the plasma membrane. Moreover, NLRP10 physically interacts with downstream components of the NOD1 signalling pathway, such as RIP2, TAK1 and NEMO. Taken together, our data revealed a novel role of NLRP10 in innate immune responses towards bacterial infection and suggest that NLRP10 functions as a scaffold for the formation of the NOD1-Nodosome.
AU  - Lautz, K.*
AU  - Damm, A.*
AU  - Menning, M.*
AU  - Wenger, J.*
AU  - Adam, A.C.*
AU  - Zigrino, P.*
AU  - Kremmer, E.
AU  - Kufer, T.A.*
C1  - 10480
C2  - 30218
SP  - 1568-1583
TI  - NLRP10 enhances Shigella-induced pro-inflammatory responses.
JO  - Cell. Microbiol.
VL  - 14
IS  - 10
PB  - Wiley-Blackwell
PY  - 2012
SN  - 1462-5814
ER  - 

TY  - JOUR
AB  - The pattern-recognition molecule Nod1 is a critical sensor for bacterial derived diaminopimelic acid-containing peptidoglycan fragments which induces innate immune responses in epithelial cells. Here we report the subcellular localization of this protein in human epithelial cells. Nod1 is localized in the cytosol and at the plasma membrane in human cells. This membrane association is dependent on the integrity of the protein, on its signalling capacity and on an intact actin cytoskeleton. Signalling-inactive mutants of Nod1 or disruption of the actin cytoskeleton interferes with this localization pattern and impacts on downstream NF-kappaB activation. Moreover, the invasive bacterium Shigella flexneri was used as a model for physiological activation of Nod1. Imaging revealed that Nod1 is recruited to the site of bacterial entry, where it colocalizes with NEMO. Our data provide evidence that membrane association is linked to Nod1 function and, in view of recent findings on Nod2, that this may be a common feature of NLR family members.
AU  - Kufer, T.A.*
AU  - Kremmer, E.
AU  - Adam, A.C.*
AU  - Philpott, D.J.*
AU  - Sansonetti, P.J.*
C1  - 2515
C2  - 25696
SP  - 477-486
TI  - The pattern-recognition molecule Nod1 is localized at the plasma membrane at sites of bacterial interaction.
JO  - Cell. Microbiol.
VL  - 10
IS  - 2
PB  - Blackwell
PY  - 2008
SN  - 1462-5814
ER  - 

TY  - JOUR
AB  - Hepatitis B virus (HBV) is an important human pathogen, which targets the liver extremely efficient, gaining access to hepatocytes by a so far unknown receptor and replicating in a hepatocyte-specific fashion. Cell differentiation seems to determine HBV replication. We here show that the level of hepatocyte differentiation, as indicated by hepatocyte polarization and metabolic activity, is closely correlated to the transcription of the HBV RNA pregenome. Pregenome transcription determined the level of HBV replication in various cell lines of hepatocellular origin and in primary human hepatocytes. A variety of hepatocyte-enriched nuclear factors have been described to regulate transcription of the pregenome, but it remained unknown which factors link HBV replication to hepatocyte differentiation. We determined that high expression levels of HNF4alpha but not its potential cofactors or other hepatocyte-enriched transcription factors were essential for efficient HBV replication, and link it to hepatocyte differentiation. HNF1alpha contributed to the control of HBV replication because it regulated the expression of HNF4alpha. Thus, a concerted action of HNF4alpha and HNF1alpha, which also determines morphological and functional differentiation of hepatocytes, links HBV replication to hepatocyte differentiation.
AU  - Quasdorff, M.*
AU  - Hösel, M.*
AU  - Odenthal, M.*
AU  - Zedler, U.*
AU  - Bohne, F.*
AU  - Gripon, P.*
AU  - Dienes, H.P.*
AU  - Drebber, U.*
AU  - Stippel, D.*
AU  - Goeser, T.*
AU  - Protzer, U.
C1  - 2498
C2  - 25465
SP  - 1478-1490
TI  - A concerted action of HNF4alpha and HNF1alpha links hepatitis B virus replication to hepatocyte differentiation.
JO  - Cell. Microbiol.
VL  - 10
IS  - 7
PB  - Blackwell
PY  - 2008
SN  - 1462-5814
ER  - 

TY  - JOUR
AB  - Because of their beneficial impact on plants, the highly diverse mycorrhizal fungi grouped in the order Sebacinales lay claim to high ecological and agricultural significance. Here, we describe for the first time associations of Sebacinoid members with bacteria. Using quantitative PCR, denaturating gradient gel electrophoresis and fluorescence in situ hybridization, we detected an intimate association between Piriformospora indica and Rhizobium radiobacter, an alpha-Proteobacterium. The stability of the association, vertical transmission of the bacteria during asexual fungal reproduction and fungal plant colonization was monitored using R. radiobacter-specific primers. Treatment of mycelium or fungal protoplasts with antibiotics highly efficient against the free bacteria failed to cure the fungus. Barley seedlings dip-inoculated with R. radiobacter showed growth promotion and systemic resistance to the powdery mildew fungus Blumeria graminis comparable to P. indica inoculation. By screening additional isolates of the Sebacina vermifera complex, three species-specific associations with bacteria from the genera Paenibacillus, Acinetobacter and Rhodococcus were found. These findings suggest that Sebacinales species regularly undergo complex interactions involving host plants and bacteria reminiscent of other ectomycorrhizal and endomycorrhizal associations.
AU  - Sharma, M.*
AU  - Schmid, M.
AU  - Rothballer, M.
AU  - Hause, G.*
AU  - Zuccaro, A.*
AU  - Imani, J.*
AU  - Kämpfer, P.*
AU  - Domann, E.*
AU  - Schäfer, P.*
AU  - Hartmann, A.
AU  - Kogel, K.H.*
C1  - 2299
C2  - 25824
SP  - 2235-2246
TI  - Detection and identification of bacteria intimately associated with fungi of the order Sebacinales.
JO  - Cell. Microbiol.
VL  - 10
IS  - 11
PB  - Blackwell Publishing
PY  - 2008
SN  - 1462-5814
ER  -