• Purification of the human fibroblast growth factor 2 using novel animal-component free materials

      Bolten, Svenja Nicolin; Knoll, Anne-Sophie; Li, Zhaopeng; Gellermann, Pia; Pepelanova, Iliyana; Rinas, Ursula; Scheper, Thomas; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Elsevier BV, 2020-08)
      This paper analyzes the use of animal-component free chromatographic materials for the efficient purifi- cation of the human fibroblast growth factor 2 (hFGF-2). hFGF-2 is produced in Escherichia coli and pu- rified via three different chromatography steps, which include a strong cation exchange chromatography as a capture step, followed by heparin affinity chromatography and an anion exchange chromatography as a polishing step. The affinity chromatography step is based on the animal-derived material heparin. Chemically produced ligands provide a viable alternative to animal-derived components in production processes, since they are characterized by a defined structure which leads to reproducible results and a broad range of applications. The alternative ligands can be assigned to adsorber of the mixed-mode chromatography (MMC) and pseudo-affinity chromatography. Eight different animal-component free materials used as adsorbers in MMC or pseudo-affinity chromatog- raphy were tested as a substitute for heparin. The MMCs were cation exchangers characterized with fur- ther functional residues. The ligands of the pseudo-affinity chromatography were heparin-like ligands which are based on heparin’s molecular structure. The alternative methods were tested as a capture step and in combination with another chromatographic step in the purification procedure of hFGF-2. In each downstream step purity, recovery and yield were analysed and compared to the conventional downstream process. Two types of MMC –the column Foresight TM Nuvia TM cPrime TM from Bio-Rad Laboratories and the col- umn HiTrap TM Capto TM MMC from GE Healthcare Life Sciences - can be regarded as effective animal- component free alternatives to the heparin - based adsorber.
    • TLR4 abrogates the Th1 immune response through IRF1 and IFN-β to prevent immunopathology during L. infantum infection.

      Sacramento, Laís Amorim; Benevides, Luciana; Maruyama, Sandra Regina; Tavares, Lucas; Fukutani, Kiyoshi Ferreira; Francozo, Marcela; Sparwasser, Tim; Cunha, Fernando Queiroz; Almeida, Roque Pacheco; da Silva, João Santana; et al. (PLOS, 2020-03-25)
      A striking feature of human visceral leishmaniasis (VL) is chronic inflammation in the spleen and liver, and VL patients present increased production levels of multiple inflammatory mediators, which contribute to tissue damage and disease severity. Here, we combined an experimental model with the transcriptional profile of human VL to demonstrate that the TLR4-IFN-β pathway regulates the chronic inflammatory process and is associated with the asymptomatic form of the disease. Tlr4-deficient mice harbored fewer parasites in their spleen and liver than wild-type mice. TLR4 deficiency enhanced the Th1 immune response against the parasite, which was correlated with an increased activation of dendritic cells (DCs). Gene expression analyses demonstrated that IRF1 and IFN-β were expressed downstream of TLR4 after infection. Accordingly, IRF1- and IFNAR-deficient mice harbored fewer parasites in the target organs than wild-type mice due to having an increased Th1 immune response. However, the absence of TLR4 or IFNAR increased the serum transaminase levels in infected mice, indicating the presence of liver damage in these animals. In addition, IFN-β limits IFN-γ production by acting directly on Th1 cells. Using RNA sequencing analysis of human samples, we demonstrated that the transcriptional signature for the TLR4 and type I IFN (IFN-I) pathways was positively modulated in asymptomatic subjects compared with VL patients and thus provide direct evidence demonstrating that the TLR4-IFN-I pathway is related to the nondevelopment of the disease. In conclusion, our results demonstrate that the TLR4-IRF1 pathway culminates in IFN-β production as a mechanism for dampening the chronic inflammatory process and preventing immunopathology development.
    • Variations in microbiota composition of laboratory mice influence Citrobacter rodentium infection via variable short-chain fatty acid production.

      Osbelt, Lisa; Thiemann, Sophie; Smit, Nathiana; Lesker, Till Robin; Schröter, Madita; Gálvez, Eric J C; Schmidt-Hohagen, Kerstin; Pils, Marina C; Mühlen, Sabrina; Dersch, Petra; et al. (PLOS, 2020-03-24)
      The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Citrobacter rodentium colonization after infection. Transfer of communities from susceptible and resistant mice into germ-free mice verified that the varying susceptibilities are determined by microbiota composition. The strongest differences in colonization were observed in the cecum and could be maintained in vitro by coculturing cecal bacteria with C. rodentium. Cohousing of animals as well as the transfer of cultivable bacteria from resistant to susceptible mice led to variable outcomes in the recipient mice. Microbiome analysis revealed that a higher abundance of butyrate-producing bacteria was associated with the resistant phenotype. Quantification of short-chain fatty acid (SCFA) levels before and after infection revealed increased concentrations of acetate, butyrate and propionate in mice with delayed colonization. Addition of physiological concentrations of butyrate, but not of acetate and/or propionate strongly impaired growth of C. rodentium in vitro. In vivo supplementation of susceptible, antibiotic-treated and germ-free mice with butyrate led to the same level of protection, notably only when cecal butyrate concentration reached a concentration higher than 50 nmol/mg indicating a critical threshold for protection. In the recent years, commensal-derived primary and secondary bacterial metabolites emerged as potent modulators of hosts susceptibility to infection. Our results provide evidence that variations in SCFA production in mice fed fibre-rich chow-based diets modulate susceptibility to colonization with Enterobacteriaceae not only in antibiotic-disturbed ecosystems but even in undisturbed microbial communities. These findings emphasise the need for microbiota normalization across laboratory mouse lines for infection experiments with the model-pathogen C. rodentium independent of investigations of diet and antibiotic usage.
    • Characterization of a transcriptional TPP riboswitch in the human pathogen Neisseriameningitidis.

      Righetti, Francesco; Materne, Solange Lise; Boss, John; Eichner, Hannes; Charpentier, Emmanuelle; Loh, Edmund; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Taylor & Francis, 2020-02-20)
      Increasing evidence has demonstrated that regulatory RNA elements such as riboswitches (RS) play a pivotal role in the fine-tuning of bacterial gene expression. In this study, we investigated and characterized a novel transcriptional thiamine pyrophosphate (TPP) RS in the obligate human pathogen N. meningitidis MC58 (serogroup B). This RS is located in the 5´ untranslated region upstream of thiC gene, encoding a protein involved in TPP biosynthesis, an essential cofactor for all living beings. Primer extension revealed the transcriptional start site of thiC. Northern blot analysis of thiC mRNA and reporter gene studies confirmed the presence of an active TPP-sensing RS. Expression patterns of the wild-type RS and site-specific mutants showed that it is an OFF switch that controls transcription elongation of thiC mRNA. Interestingly, the regulatory mechanism of the meningococcal thiC RS resembles the Gram-positive Bacillus subtilis thiC RS rather than the Gram-negative Escherichia coli thiC RS. Therefore, the meningococcal thiC RS represents a rare example of transcriptional RS in a Gram-negative bacterium. We further observed that the RS is actively involved in modulating gene expression in response to different growth media and to supplemented bacterial and eukaryotic cell lysates as possible sources of nutrients in the nasopharynx. Our results suggest that RS-mediated gene regulation could influence meningococcal fitness, through the fine-tuning of biosynthesis and scavenging of nutrients and cofactors, such as thiamine.
    • MAIT cells are enriched and highly functional in ascites of patients with decompensated liver cirrhosis.

      Niehaus, Christian E; Strunz, Benedikt; Cornillet, Martin; Falk, Christine S; Schnieders, Ansgar; Maasoumy, Benjamin; Hardtke, Svenja; Manns, Michael P; Rm Kraft, Anke; Björkström, Niklas K; et al. (Wiley Online Open, 2020-02-03)
      Patients with advanced liver cirrhosis have an increased susceptibility to infections. As part of the cirrhosis-associated immune dysfunction, mucosal associated invariant T (MAIT) cells, that have the capacity to respond towards bacteria, are severely diminished in circulation and liver tissue. However, MAIT cell presence and function in the peritoneal cavity, a common anatomical site for infections in cirrhosis, remain elusive. To study this, matched peripheral blood and ascites fluid were collected from 35 patients with decompensated cirrhosis, with or without spontaneous bacterial peritonitis (SBP). MAIT cell phenotype and function were analyzed using high-dimensional flow cytometry and obtained data was compared to blood samples of healthy controls (n=24) and patients with compensated cirrhosis (n=11). We found circulating MAIT cells to be severely decreased in cirrhotic patients as compared to controls. In contrast, in ascites fluid, MAIT cells were significantly increased together with CD14+ CD16+ monocytes, ILCs, and NK cells. This was paralleled by elevated levels of several pro-inflammatory cytokines and chemokines in ascites fluid as compared to plasma. Peritoneal MAIT cells displayed an activated tissue-resident phenotype and this was corroborated by increased functional responses following stimulation with E. coli or lL-12 + IL-18 as compared to circulating MAIT cells. During SBP, peritoneal MAIT cell frequencies increased most among all major immune cell subsets, suggestive of active homing of MAIT cells to the site of infection. CONCLUSIONS: Despite severely diminished MAIT cell numbers and impaired phenotype in circulation, peritoneal MAIT cells remain abundant, activated, and highly functional in decompensated cirrhosis and are further enriched in SBP. This suggests that peritoneal MAIT cells could be of interest for immune intervention strategies in patients with decompensated liver cirrhosis and SBP.
    • Ex Vivo/In vivo Gene Editing in Hepatocytes Using "All-in-One" CRISPR-Adeno-Associated Virus Vectors with a Self-Linearizing Repair Template.

      Krooss, Simon Alexander; Dai, Zhen; Schmidt, Florian; Rovai, Alice; Fakhiri, Julia; Dhingra, Akshay; Yuan, Qinggong; Yang, Taihua; Balakrishnan, Asha; Steinbrück, Lars; et al. (Cell Press/Elsevier, 2020-01-24)
      Adeno-associated virus (AAV)-based vectors are considered efficient and safe gene delivery systems in gene therapy. We combined two guide RNA genes, Cas9, and a self-linearizing repair template in one vector (AIO-SL) to correct fumarylacetoacetate hydrolase (FAH) deficiency in mice. The vector genome of 5.73 kb was packaged into VP2-depleted AAV particles (AAV2/8ΔVP2), which, however, did not improve cargo capacity. Reprogrammed hepatocytes were treated with AIO-SL.AAV2ΔVP2 and subsequently transplanted, resulting in large clusters of FAH-positive hepatocytes. Direct injection of AIO-SL.AAV8ΔVP2 likewise led to FAH expression and long-term survival. The AIO-SL vector achieved an ∼6-fold higher degree of template integration than vectors without template self-linearization. Subsequent analysis revealed that AAV8 particles, in contrast to AAV2, incorporate oversized genomes distinctly greater than 5.2 kb. Finally, our AAV8-based vector represents a promising tool for gene editing strategies to correct monogenic liver diseases requiring (large) fragment removal and/or simultaneous sequence replacement.
    • Nasal DNA methylation profiling of asthma and rhinitis.

      Qi, Cancan; Jiang, Yale; Yang, Ivana V; Forno, Erick; Wang, Ting; Vonk, Judith M; Gehring, Ulrike; Smit, Henriëtte A; Milanzi, Edith B; Carpaij, Orestes A; et al. (2020-01-14)
    • Efficacy of rituximab in difficult-to-manage autoimmune hepatitis: Results from the International Autoimmune Hepatitis Group.

      Than, Nwe Ni; Hodson, James; Schmidt-Martin, Daniel; Taubert, Richard; Wawman, Rebecca E; Botter, Meemee; Gautam, Nishant; Bock, Kilian; Jones, Rebecca; Appanna, Gautham D; et al. (Elsevier, 2019-12-01)
      Twenty-two patients with type-1 AIH were included, with a median age of 40 years at diagnosis (range 19-79); 15/22 (68%) were female and 18/22 (82%) were Caucasian. The median period from diagnosis to the end of follow-up in these patients was 11 years (range 3-28). Values of alanine aminotransferase, aspartate aminotransferase and albumin improved significantly following rituximab therapy, and were sustained for up to 2 years (all p ≪0.001). Prednisolone doses were significantly reduced by 12 months post-treatment (p = 0.003), with 13/21 (62%) patients having a dose reduction. Over a median post-treatment follow-up period of 6 years (range 1-10), 5 patients developed AIH flares at a median of 22 months post-treatment, giving an estimated 71% freedom from AIH flare at 2 years. Four of these patients received a second course of treatment, of whom 2 had subsequent further flares. No serious adverse events attributable to rituximab were recorded.
    • Parasites in brains of wild rodents (Arvicolinae and Murinae) in the city of Leipzig, Germany

      Waindok, Patrick; Özbakış-Beceriklisoy, Gökben; Janecek-Erfurth, Elisabeth; Springer, Andrea; Pfeffer, Martin; Leschnik, Michael; Strube, Christina; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Elsevier, 2019-12-01)
      Small rodents serve as intermediate or paratenic hosts for a variety of parasites and may participate in thetransmission of these parasites into synanthropic cycles. Parasites with neuroinvasive stages, such asToxoplasmagondiiorToxocara canis, can cause detrimental damage in the brain of intermediate or paratenic hosts.Therefore, the occurrence of neuroinvasive parasite stages was evaluated in brains of wild rodents captured inthe city of Leipzig, Germany. In addition, a few specimens from the cities of Hanover, Germany, and Vienna,Austria were included, resulting in a total of 716 rodents collected between 2011 and 2016. Brains were in-vestigated for parasitic stages by microscopic examination of native tissue, artificially digested tissue as well asGiemsa-stained digestion solution to verify positive results. Infective stages of zoonotic ascarids or other hel-minths were not detected in any sample, while coccidian cysts were found in 10.1% (95% CI: 7.9–12.5%; 72/716) of examined brains. The most abundant rodent species in the study was the bank vole (Myodes glareolus;Arvicolinae), showing an infection rate with cerebral cysts of 13.9% (95% CI: 11.0–17.8%; 62/445), while 2.7%(95% CI: 1.0–5.8%; 6/222) of yellow-necked mice (Apodemusflavicollis; Murinae) were infected. Generalizedlinear modelling revealed a statistically significant difference in prevalence betweenM. glareolusandA.flavi-collis, significant local differences as well as an effect of increasing body mass on cyst prevalence. Coccidian cystswere differentiated by amplification of the18S rRNAgene and subsequent sequencing. The majority of iden-tifiable cysts (97.9%) were determined asFrenkelia glareoli, a coccidian species mainly circulating betweenM.glareolusas intermediate and buzzards (Buteospp.) as definitive hosts. The zoonotic pathogenToxoplasma gondiiwas confirmed in oneM. glareolusoriginating from the city of Leipzig. Overall, it can be concluded that neu-roinvasion of zoonotic parasites seems to be rare inM. glareolusandA.flavicollis.
    • Stability and Biological Activity of E. coli Derived Soluble and Precipitated Bone Morphogenetic Protein-2.

      Quaas, Bastian; Burmeister, Laura; Li, Zhaopeng; Satalov, Alexandra; Behrens, Peter; Hoffmann, Andrea; Rinas, Ursula; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Springer, 2019-11-20)
      PURPOSE: There is a plethora of studies on recombinant human bone morphogenetic protein-2 (rhBMP-2) application and delivery systems, but surprisingly few reports address the biophysical properties of the protein which are of crucial importance to develop effective delivery systems or to solve general problems related to rhBMP-2 production, purification, analysis and application. METHODS:The solubility, stability and bioactivity of rhBMP-2 obtained by renaturation of E. coli derived inclusion bodies was assessed at different pH and in different buffer systems using (dynamic) light scattering and thermal shift assays as well as intrinsic fluorescence measurements and luciferase based bioassays. RESULTS: rhBMP-2 is poorly soluble at physiological pH and higher. The presence of divalent anions further decreases the solubility even under acidic conditions. Thermal stability analyses revealed that rhBMP-2 precipitates are more stable compared to the soluble protein. Moreover, correctly folded rhBMP-2 is also bioactive as precipitated protein and precipitates readily dissolve under appropriate buffer conditions. Once properly formed rhBMP-2 also retains biological activity after temporary exposure to high concentrations of chaotropic denaturants. However, care should be taken to discriminate bioactive rhBMP-2 precipitates from misfolded rhBMP-2 aggregates, e.g. resolvability in MES buffer (pH 5) and a discrete peak in thermoshift experiments are mandatory for correctly folded rhBMP-2. CONCLUSIONS: Our analysis revealed that E. coli derived rhBMP-2 precipitates are not only bioactive but are also more stable compared to the soluble dimeric molecules. Knowledge about these unusual properties will be helpful to design improved delivery systems requiring lower amounts of rhBMP-2 in clinical applications.
    • Groundwater, soil and compost, as possible sources of virulent and antibiotic-resistant Pseudomonas aeruginosa.

      Kaszab, Edit; Radó, Júlia; Kriszt, Balázs; Pászti, Judit; Lesinszki, Virág; Szabó, Ádám; Tóth, Gergő; Khaledi, Ariane; Szoboszlay, Sándor; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Taylor & Francis, 2019-11-18)
      Pseudomonas aeruginosa is a major public health concern all around the world. In the frame of this work, a set of diverse environmental P. aeruginosa isolates with various antibiotic resistance profiles were examined in a Galleria mellonella virulence model. Motility, serotypes, virulence factors and biofilm-forming ability were also examined. Molecular types were determined by pulsed-field gel electrophoresis (PFGE). Based on our results, the majority of environmental isolates were virulent in the G. mellonella test and twitching showed a positive correlation with mortality. Resistance against several antibiotic agents such as Imipenem correlated with a lower virulence in the applied G. mellonella model. PFGE revealed that five examined environmental isolates were closely related to clinically detected pulsed-field types. Our study demonstrated that industrial wastewater effluents, composts, and hydrocarbon-contaminated sites should be considered as hot spots of high-risk clones of P. aeruginosa.
    • Quantitation of large, middle and small hepatitis B surface proteins in HBeAg-positive patients treated with peginterferon alfa-2a.

      Rinker, Franziska; Bremer, Corinna M; Schröder, Kathrin; Wiegand, Steffen B; Bremer, Birgit; Manns, Michael P; Kraft, Anke R; Wedemeyer, Heiner; Yang, Lei; Pavlovic, Vedran; et al. (Wiley, 2019-11-13)
      BACKGROUND & AIMS: Hepatitis B virus (HBV) contains three viral surface proteins, large, middle and small hepatitis B surface protein (LHBs, MHBs, SHBs). Proportions of LHBs and MHBs are lower in patients with inactive versus active chronic infection. Interferon alfa may convert HBeAg-positive chronic hepatitis B (CHB) to an inactive carrier state, but prediction of sustained response is unsatisfactory. The aim of this study was to test the hypothesis that quantification of MHBs and LHBs may allow for a better prognosis of therapeutic response than total hepatitis B surface antigen (HBsAg) concentration. METHODS: HBs proteins were measured before and during peginterferon alfa-2a therapy in serum from 127 Asian patients with HBeAg-positive CHB. Sustained response was defined as hepatitis B e antigen (HBeAg) seroconversion 24 weeks post-treatment. RESULTS: Mean total HBs levels were significantly lower in responders versus nonresponders at all time points (P<.05) and decreased steadily during the initial 24 weeks' treatment (by 1.16 versus 0.86 ng/mL in responders/nonresponders, respectively) with unchanged relative proportions. Genotype B had a twofold higher proportion of LHBs than genotype C (13% versus 6%). HBV DNA, HBeAg, HBsAg, and HBs protein levels predicted response equally well but not optimally (area under the ROC curve values >0.70). CONCLUSIONS: HBs proteins levels differ by HBV genotype. However, quantification of HBs proteins has no advantage over the already established HBsAg assays to predict response to peginterferon alfa-2a therapy in HBeAg-positive patients.
    • The role of epigenetics in the development of childhood asthma.

      Qi, Cancan; Xu, Cheng-Jian; Koppelman, Gerard H; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (2019-11-10)
      Introduction: The development of childhood asthma is caused by a combination of genetic factors and environmental exposures. Epigenetics describes mechanisms of (heritable) regulation of gene expression that occur without changes in DNA sequence. Epigenetics is strongly related to aging, is cell-type specific, and includes DNA methylation, noncoding RNAs, and histone modifications.Areas covered: This review summarizes recent epigenetic studies of childhood asthma in humans, which mostly involve studies of DNA methylation published in the recent five years. Environmental exposures, in particular cigarette smoking, have significant impact on epigenetic changes, but few of these epigenetic signals are also associated with asthma. Several asthma-associated genetic variants relate to DNA methylation. Epigenetic signals can be better understood by studying their correlation with gene expression, which revealed higher presence and activation of blood eosinophils in asthma. Strong associations of nasal methylation signatures and atopic asthma were identified, which were replicable across different populations.Expert commentary: Epigenetic markers have been strongly associated with asthma, and might serve as biomarker of asthma. The causal and longitudinal relationships between epigenetics and disease, and between environmental exposures and epigenetic changes need to be further investigated. Efforts should be made to understand cell-type-specific epigenetic mechanisms in asthma.
    • Unexpected roles for ADH1 and SORD in catalyzing the final step of erythritol biosynthesis.

      Schlicker, Lisa; Szebenyi, Doletha M E; Ortiz, Semira R; Heinz, Alexander; Hiller, Karsten; Field, Martha S; HIRI, Helmholtz-Institut für RNA-basierte Infektionsforschung, Josef-Shneider Strasse 2, 97080 Würzburg, Germany. (American Society for Biochemistry and Molecular Biology, 2019-11-01)
      The low-calorie sweetener erythritol is endogenously produced from glucose through the pentose phosphate pathway in humans. Erythritol is of medical interest because elevated plasma levels of this polyol are predictive for visceral adiposity gain and development of type 2 diabetes. However, the mechanisms behind these associations remain unknown because the erythritol biosynthesis pathway, particularly the enzyme catalyzing the final step of erythritol synthesis (reduction of erythrose to erythritol), is not characterized. In this study, we purified two enzymes from rabbit liver capable of catalyzing the conversion of erythrose to erythritol: alcohol dehydrogenase 1 (ADH1) and sorbitol dehydrogenase (SORD). Both recombinant human ADH1 and SORD reduce erythrose to erythritol, using NADPH as a co-factor, and cell culture studies indicate that this activity is primarily NADPH-dependent. We found that ADH1 variants vary markedly in both their affinity for erythrose and their catalytic capacity (turnover number). Interestingly, the recombinant protein produced from the ADH1B2 variant, common in Asian populations, is not active when NADPH is used as a co-factor in vitro We also confirmed SORD contributes to intracellular erythritol production in human A549 lung cancer cells, where ADH1 is minimally expressed. In summary, human ADH1 and SORD catalyze the conversion of erythrose to erythritol, pointing to novel roles for two dehydrogenase proteins in human glucose metabolism that may contribute to individual responses to diet. Proteomics data are available via ProteomeXchange with identifier PXD015178.
    • DSA are associated with more graft injury, more fibrosis and upregulation of rejection associated transcripts in subclinical rejection.

      Höfer, Anne; Jonigk, Danny; Hartleben, Björn; Verboom, Murielle; Hallensleben, Michael; Hübscher, Stefan G; Manns, Michael P; Jaeckel, Elmar; Taubert, Richard; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Lippincott, Williams & Wilkins , 2019-10-23)
      Background: Subclinical T cell-mediated rejection (subTCMR) is commonly found after liver transplantation and has a good short-term prognosis, even when it is left untreated. Donor-specific antibodies (DSA) are putatively associated with a worse prognosis for recipient and graft after liver transplantation. Methods: To assess the immune regulation in subTCMR grafts, gene expression of 93 transcripts for graft injury, tolerance and immune regulation was analyzed in 77 biopsies with “no histological rejection” (NHR; n=25), “clinical TCMR” (cTMCR; n=16) and subTCMR (n=36). In addition, all available subTCMR biopsies (n=71) were tested for DSA with bead assays. Results: SubTCMR showed heterogeneous and intermediate expression profiles of transcripts that were upregulated in cTCMR. Graft gene expression suggested a lower activation of effector lymphocytes and a higher activation of regulatory T cells in grafts with subTCMR compared to cTCMR.DSA positivity in subTCMR was associated with histological evidence of more severe graft inflammation and fibrosis. This more severe DSA+ associated graft injury in subTCMR was converged with an upregulation of cTCMR associated transcripts. In nonsupervised analysis DSA positive subTCMR mostly clustered together with cTCMR, while DSA negative subTCMR clustered together with NHR. Conclusion: T cell-mediated rejection seem to form a continuum of alloimmune activation. Although subTCMR exhibited less expression of TCMR associated transcript, DSA positivity in subTCMR was associated with an upregulation of rejection associated transcripts. The identification of DSA positive subclinical rejection might help to define patients with more inflammation in the graft and development of fibrosis.
    • Soluble immune markers in the different phases of chronic hepatitis B virus infection

      Wiegand, Steffen B.; Beggel, Bastian; Wranke, Anika; Aliabadi, Elmira; Jaroszewicz, Jerzy; Xu, Cheng Jian; Li, Yang; Manns, Michael P.; Lengauer, Thomas; Wedemeyer, Heiner; et al. (Nature publishing group, 2019-10-01)
      Chronic hepatitis B virus (HBV) infection may follow four different consecutive phases, which are defined by virology as well as biochemical markers and differ in terms of prognosis and need for antiviral treatment. Currently, host responses reflected by immune markers are not considered in this definition. We aimed to study soluble immune markers and their distribution in different phases of chronic HBV infection. In this cross-sectional retrospective study, we investigated a panel of 14 soluble immune markers (SIM) including CXCL10 in 333 patients with chronic HBV infection. In a small cohort of HBeAg positive patients we analyzed SIM before and after HBeAg seroconversion and compared seroconverters to patients with unknown outcome. Significant differences were documented in the levels of several SIM between the four phases of chronic HBV infection. The most pronounced difference among all investigated SIM was observed for CXCL10 concentrations with highest levels in patients with hepatitis. TGF-β and IL-17 revealed different levels between HBeAg negative patients. HBeAg positive patients with HBeAg seroconversion presented higher amounts of IL-12 before seroconversion compared to HBeAg positive patients with unknown follow up. SIM such as CXCL10 but also IL-12, TGF-β and IL-17 may be useful markers to further characterize the phase of chronic HBV infection.
    • Catalytically Active Cas9 Mediates Transcriptional Interference to Facilitate Bacterial Virulence.

      Ratner, Hannah K; Escalera-Maurer, Andrés; Le Rhun, Anaïs; Jaggavarapu, Siddharth; Wozniak, Jessie E; Crispell, Emily K; Charpentier, Emmanuelle; Weiss, David S; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Elsevier; Cell Press, 2019-06-24)
      In addition to defense against foreign DNA, the CRISPR-Cas9 system of Francisella novicida represses expression of an endogenous immunostimulatory lipoprotein. We investigated the specificity and molecular mechanism of this regulation, demonstrating that Cas9 controls a highly specific regulon of four genes that must be repressed for bacterial virulence. Regulation occurs through a protospacer adjacent motif (PAM)-dependent interaction of Cas9 with its endogenous DNA targets, dependent on a non-canonical small RNA (scaRNA) and tracrRNA. The limited complementarity between scaRNA and the endogenous DNA targets precludes cleavage, highlighting the evolution of scaRNA to repress transcription without lethally targeting the chromosome. We show that scaRNA can be reprogrammed to repress other genes, and with engineered, extended complementarity to an exogenous target, the repurposed scaRNA:tracrRNA-FnoCas9 machinery can also direct DNA cleavage. Natural Cas9 transcriptional interference likely represents a broad paradigm of regulatory functionality, which is potentially critical to the physiology of numerous Cas9-encoding pathogenic and commensal organisms.
    • Ten-year efficacy and safety of tenofovir disoproxil fumarate treatment for chronic hepatitis B virus infection.

      Marcellin, Patrick; Wong, Dave; Sievert, William; Buggisch, Peter; Petersen, Jörg; Flisiak, Robert; Manns, Michael; Kaita, Kelly; Krastev, Zahari; Lee, Samuel S; et al. (Wiley-Blackwell, 2019-05-28)
      Background & Aims Tenofovir disoproxil fumarate (TDF) is a first‐line treatment for chronic hepatitis B (CHB). We aimed to describe the efficacy and safety profiles of TDF treatment for up to 10 years in a well‐described cohort of CHB patients. Methods Hepatitis B e antigen (HBeAg)‐negative and HBeAg‐positive patients from two randomised, double‐blind trials (ClinicalTrials. gov: NCT00117676 and NCT00116805) completed 48 weeks of randomised treatment with TDF or adefovir dipivoxil. A subset of these patients was then eligible to receive open‐label TDF treatment for up to 10 years. At Year 10, patients were assessed for virological suppression, alanine aminotransferase (ALT) normalisation, serological response, safety, and tolerability. Results Of 641 randomised and treated patients, 585 (91%) entered the open‐label extension phase with 203 (32%) patients completing Year 10 of the study. At Year 10, 118/118 (100%) of HBeAg‐negative patients and 78/80 (98%) of HBeAg‐positive patients with available data achieved hepatitis B virus (HBV) DNA <69 IU/mL, while 88/106 (83%) and 60/77 (78%) patients achieved ALT normalisation, respectively. Of the 23 patients with HBeAg status available at Year 10, 12 (52%) and six (27%) experienced HBeAg loss and seroconversion, respectively. No resistance to TDF was documented up to Year 10. In the period between Year 8 and Year 10, the safety profile of TDF was similar to previous reports, with few patients experiencing renal‐ or bone‐related adverse events. Conclusions Over 10 years, TDF had a favourable safety profile, was well tolerated, and resulted in continued maintenance of virological suppression with no documented resistance.
    • A combined in silico and in vitro study on mouse Serpina1a antitrypsin-deficiency mutants.

      Eggenschwiler, Reto; Patronov, Atanas; Hegermann, Jan; Fráguas-Eggenschwiler, Mariane; Wu, Guangming; Cortnumme, Leon; Ochs, Matthias; Antes, Iris; Cantz, Tobias; TWINCORE, Zentrum für experimentelle und klinische Infektionsforschung GmbH,Feodor-Lynen Str. 7, 30625 Hannover, Germany. (Springer-Nature, 2019-05-16)
      Certain point-mutations in the human SERPINA1-gene can cause severe α1-antitrypsin-deficiency (A1AT-D). Affected individuals can suffer from loss-of-function lung-disease and from gain-of-function liver-disease phenotypes. However, age of onset and severity of clinical appearance is heterogeneous amongst carriers, suggesting involvement of additional genetic and environmental factors. The generation of authentic A1AT-D mouse-models has been hampered by the complexity of the mouse Serpina1-gene locus and a model with concurrent lung and liver-disease is still missing. Here, we investigate point-mutations in the mouse Serpina1a antitrypsin-orthologue, which are homolog-equivalent to ones known to cause severe A1AT-D in human. We combine in silico and in vitro methods and we find that analyzed mutations do introduce potential disease-causing properties into Serpina1a. Finally, we show that introduction of the King’s-mutation causes inactivation of neutrophil elastase inhibitory-function in both, mouse and human antitrypsin, while the mouse Z-mutant retains activity. This work paves the path to generation of better A1AT-D mouse-models.
    • miR-181a/b-1 controls thymic selection of Treg cells and tunes their suppressive capacity.

      Łyszkiewicz, Marcin; Winter, Samantha J; Witzlau, Katrin; Föhse, Lisa; Brownlie, Rebecca; Puchałka, Jacek; Verheyden, Nikita A; Kunze-Schumacher, Heike; Imelmann, Esther; Blume, Jonas; et al. (PLOS, 2019-03-01)
      The interdependence of selective cues during development of regulatory T cells (Treg cells) in the thymus and their suppressive function remains incompletely understood. Here, we analyzed this interdependence by taking advantage of highly dynamic changes in expression of microRNA 181 family members miR-181a-1 and miR-181b-1 (miR-181a/b-1) during late T-cell development with very high levels of expression during thymocyte selection, followed by massive down-regulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus but simultaneously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg-cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1-deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of cytotoxic T-lymphocyte-associated 4 (CTLA-4) protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function.