Chronic Stage Of Infection Research Articles

Transient elastography technology role assessment during the diagnosis and treatment of patients with chronic hepatitis B virus infection

Objective: To explore the role of transient elastography technology in the assessment of disease staging and treatment in patients with chronic hepatitis B virus (HBV) infection. Methods: Patients who were clinically diagnosed with chronic HBV infection at Beijing Tsinghua Changgung Hospital from January 2018 to December 2021 was collected. Liver stiffness measurement (LSM) examination was performed more than once by transient elastography. The count data were expressed as cases (%) and the χ (2) test was made. Fisher's exact test was used with theoretical frequency less than 5. The measurement data between two groups was compared by t-test. Multiple groups were compared with an analysis of variance. Results: 1 055 patients were included in this study, including 669 (63.4%) males and 386 (36.6%) females. 757 (71.8%) patients were untreated. Among the untreated patients, the LSM value in the immune clearance (10.2 ± 3.8) kPa (187 cases, 40.4%), and the reactivation stages (9.1 ± 3.4) kPa (114 cases, 24.6%) was significantly higher than that in the immune tolerance (8.7 ± 3.6) kPa (78 cases, 16.8%) and immune control stages (8.4 ± 3.5) KPa (84 cases, 18.1%), and the difference between the four groups was statistically significant (F = 5.31 and P = 0.03). With ALT (male: 30 U/L, female: 19 U/L) as defined the normal value, the LSM value in the immune tolerance and the immune control stages were (5.8 ± 0.9) kPa and (7.1 ± 2.5) kPa, respectively, which were significantly lower than those of patients in the immune tolerance and immune control stages, and the difference was statistically significant (P < 0.01). There were 294 (38.8%) patients with uncertain period, excluding patients with fatty liver. Patients with uncertain periods were divided into four gray zone (GZ) groups: immune tolerance stage: LSM (5.1 ± 1.3) kPa was significantly lower than GZ-A (6.5 ± 2.4) kPa, t = 2.06, P = 0.03, and the difference was statistically significant; immune control stage: LSM was (5.6 ± 1.5) kPa, which was also lower than GZ-C (6.8 ± 1.3) kPa, t = 3.08, P = 0.02, and the difference was statistically significant; immune clearance stage: LSM > 8.0 kPa. LSM values showed a year-by-year reduction in patients with expanded indications who started antiviral treatment and were followed up for three years. Conclusion: The LSM value is significantly lower after the decrease of the defined high-normal ALT value in patients with the immune tolerance and immune control stages of chronic HBV infection. The LSM values of GZ-A and GZ-C in the uncertain periods of chronic HBV infection are higher than those of patients in the immune tolerance and immune control stages.

Plasma virome dynamics in chronic hepatitis B virus infected patients.

The virome remains an understudied domain of the human microbiome. The role of commensal viruses on the outcome of infections with known pathogens is not well characterized. In this study we aimed to characterize the longitudinal plasma virome dynamics in chronic hepatitis B virus (HBV) infected patients. Eighty-five longitudinal plasma samples were collected from 12 chronic HBV infected individuals that were classified in the four stages of HBV infection. The virome was characterized with an optimized viral extraction protocol and deep-sequenced on a NextSeq 2500 platform. The plasma virome was primarily composed of members of the Anello- Flavi-, and Hepadnaviridae (HBV) families. The virome structure and dynamics did not correlate with the different stages of chronic HBV infection nor with the administration of antiviral therapy. We observed a higher intrapersonal similarity of viral contigs. Genomic analysis of viruses observed in multiple timepoint demonstrated the presence of a dynamic community. This study comprehensively assessed the blood virome structure in chronic HBV infected individuals and provided insights in the longitudinal development of this viral community.

ASXL1 disruption preserves CD8 T cell exhaustion-progenitor epigenetic programming during chronic stimulation

Abstract Differentiation of CD8 T cells into a terminally exhausted state is a major hurdle limiting efficacy of both immune checkpoint blockade and adoptive cellular immunotherapy approaches. Prior studies describing disruption of the epigenetic regulators DNMT3A and TET2 in CD8 T cells have revealed a critical role of DNA methylation in repressing the proliferative capacity and effector potential of CD8 T cells during exhaustion. Disruption of these genes has also been noted to preserve the proliferative capacity of hematopoietic stem cells (HSCs), resulting in clonal hematopoiesis (CH) and establishing the broader concept that these epigenetic regulators control cellular developmental potential. In addition to DNMT3A and TET2, the histone modifier ASXL1 is a critical regulator controlling CH. Here we report that disruption of ASXL1 in CD8 T cells preserved a stem-like phenotype denoted by increased TCF1 expression, IFN-γ production during chronic infection. At the chronic stage of infection, ASXL1 KO CD8 T cells retained a heightened ability to undergo a proliferative burst during PD-L1 blockade. Genome-wide epigenetic profiling demonstrated that disruption of ASXL1 resulted in inhibition of DNA methylation accompanied by changes in chromatin accessibility. These data document crosstalk between histone modifications and DNA methylation in regulating the transition of stem-like progenitor T cells into terminally exhausted T cells. Collectively, these data demonstrate that ASXL1 is a novel epigenetic regulator controlling development of exhausted CD8 T cells and represents a novel immunotherapeutic target for improving responses to T cell-based cancer immunotherapy.

Programming of checkpoint blockade responsive exhausted T cells by rheostatic IL-2 signals during priming by dendritic cells

Abstract Stem-like progenitor exhausted CD8 T cells are critical for maintaining long-term resistance during chronic infections and cancer, and represent an important checkpoint blockade immunotherapy target for functional reinvigoration and disease control. Here, we show a fate-deterministic role of rheostatic IL-2 signals and differential DC priming in programming the development of stem-like progenitor exhausted CD8 T cells during chronic viral infection. In vivo fate-tracking studies reveal that strong IL-2 signals during priming drive terminal differentiation. In contrast, tempered IL-2 signals are associated with TCF-1 Histem-like precursors, which give rise to progenitor exhausted CD8 T cells, capable of long-term persistence and potent responsiveness to anti-PD-1 therapy in later stages of chronic viral infection. In the context of human tumors as well, single cell RNA-seq analyses of total or antigen-specific tumor infiltrating lymphocytes show an inverse relationship of IL-2 signaling signature with T cell stemness, as well as checkpoint blockade therapy outcomes in melanoma. Our studies further show that the rheostatic control of exhausted T cell fates by differential IL-2 signals is physiologically mediated through differential cell surface expression of IL-2Rα during early stages of T cell activation, which in turn is pioneered during priming by distinct dendritic cell subsets. Notably, moderation of in vivo IL-2 signals during priming promotes the development of stem-like TCF-1 Hilineage, thus supporting a unique strategy for improving clinical immunotherapy outcomes by enhancing the development of long-lived, therapy-responsive stem-like cells with vigorous effector expansion capabilities. Pediatric Cancer Research Foundation to SS, the Rachel Lynn Henley Foundation to VK, the Hopes and Smiles For Children Foundation to VK, In Concert for Cancer Foundation to VK and the National Institutes of Health (CA254168 to TP; CA225517 to PN; AI132819, AI103748 to SS; 5P30CA015704; AI154363 to VK)

Erythrocytic, Enzymatic, and Histological Markers of Oxidative Stress in Subacute and Chronic Stage Infections in Wistar Rats (Rattus norvegicus) Infected with Trypanosoma brucei brucei

Trypanosomiasis is a complex of diseases caused by a haemoprotozoan parasite of medical and veterinary importance. One of the leading factors that cause morbidity and death in trypanosomiasis is oxidative stress. The oxidative stress biomarkers in trypanosomiasis at the subacute and chronic stages of infection were investigated in this study. A total of twenty-four Wistar rats were used; the animals were placed in two groups: group A (subacute and chronic) and group B (control). The weight and body temperature of the experimental animals were determined using a digital weighing balance and thermometer. A hematology analyzer was used to determine the erythrocyte indices. Spectrophotometry was used to estimate enzyme (superoxide dismutase, catalase, and glutathione) activities in the serum, kidney, and liver of experimental animals. Liver, kidney, and spleen were harvested and analyzed for histological changes. The mean body weight of the infected decreased compared to the control (P < 0.05). The mean body temperature of infected individuals increased (35-37°C) compared to the control (P < 0.05). The erythrocyte indices of the infected and control groups indicate a significant decrease (P < 0.05). In erythrocyte indices, only MCHC indicated a nonsignificant decrease (P > 0.05). The SOD of serum shows a significant increase (P < 0.05), and no significant increase SOD (P > 0.05) in kidney and the liver SOD indicates a significant decrease (P < 0.05). The serum, kidney, and liver show a significant increase (P < 0.05) in CAT. The serum GSH from the findings indicates a nonsignificant increase (P > 0.05), and the kidney and liver GSH shows a significant increase (P < 0.05). The correlation analysis for SOD shows nonsignificant negative correlation for serum/kidney, and the serum/liver and kidney/liver show significant positive correlation. The result of CAT shows significant correlations for serum and kidney, serum and liver, and kidney/liver with a positive correlation. The GSH result shows no significant negative correlation for serum/kidney and no significant positive correlation for serum/liver and kidney/liver. The histological damage in the kidney, liver, and spleen was much higher in the chronic stage than in the subacute stage and no tissue damage in the control group. In conclusion, subacute and chronic stage trypanosome infection is associated with changes in hematological indices, antioxidants of the liver, spleen and kidney, and histological architecture.

IL-22-producing CD3 + CD8- T cells increase in immune clearance stage of chronic HBV infection and correlate with the response of Peg-interferon treatment

Interleukin (IL)-22 regulates host defense. This study investigated the predominant IL-22-producing cell subsets under HBV associated immune stages. We found circulating IL-22-producing CD3 + CD8- T cells were significantly increased in immune active (IA) stage than those in immunotolerant stage, inactive carrier and healthy controls (HCs). The plasma IL-22 level was higher in IA and HBeAg-negative CHB compared to HCs. Importantly, CD3 + CD8- T cells were identified as the predominant source of plasma IL-22 production. Up-regulated IL-22-producing CD3 + CD8- T cells obviously correlated with the grade of intrahepatic inflammation. The proportions of IL-22-producing CD3 + CD8- T cells were significantly down-regulated after 48 weeks of Peg-interferon treatment, and the differences were of great significance in patients with normalize ALT levels at 48 weeks, rather than those with elevated ALT levels. In conclusion, IL-22 might play a proinflammatory function in.chronic HBV infected patients with active inflammation and Peg-interferon treatment could attenuate the degree of liver inflammation through down-regulating IL-22-producing CD3 + CD8- T cells.

A necroptosis-independent function of RIPK3 promotes immune dysfunction and prevents control of chronic LCMV infection

Necroptosis is a lytic and inflammatory form of cell death that is highly constrained to mitigate detrimental collateral tissue damage and impaired immunity. These constraints make it difficult to define the relevance of necroptosis in diseases such as chronic and persistent viral infections and within individual organ systems. The role of necroptotic signalling is further complicated because proteins essential to this pathway, such as receptor interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL), have been implicated in roles outside of necroptotic signalling. We sought to address this issue by individually defining the role of RIPK3 and MLKL in chronic lymphocytic choriomeningitis virus (LCMV) infection. We investigated if necroptosis contributes to the death of LCMV-specific CD8+ T cells or virally infected target cells during infection. We provide evidence showing that necroptosis was redundant in the pathogenesis of acute forms of LCMV (Armstrong strain) and the early stages of chronic (Docile strain) LCMV infection in vivo. The number of immune cells, their specificity and reactivity towards viral antigens and viral loads are not altered in the absence of either MLKL or RIPK3 during acute and during the early stages of chronic LCMV infection. However, we identified that RIPK3 promotes immune dysfunction and prevents control of infection at later stages of chronic LCMV disease. This was not phenocopied by the loss of MLKL indicating that the phenotype was driven by a necroptosis-independent function of RIPK3. We provide evidence that RIPK3 signaling evoked a dysregulated type 1 interferone response which we linked to an impaired antiviral immune response and abrogated clearance of chronic LCMV infection.

Whole blood transcriptome profiles of trypanotolerant and trypanosusceptible cattle highlight a differential modulation of metabolism and immune response during infection by Trypanosoma congolense

Animal African trypanosomosis, caused by blood protozoan parasites transmitted mainly by tsetse flies, represents a major constraint for millions of cattle in sub-Saharan Africa. Exposed cattle include trypanosusceptible indicine breeds, severely affected by the disease, and West African taurine breeds called trypanotolerant owing to their ability to control parasite development, survive and grow in enzootic areas. Until now the genetic basis of trypanotolerance remains unclear. Here, to improve knowledge of the biological processes involved in trypanotolerance versus trypanosusceptibility, we identified bovine genes differentially expressed in five West African cattle breeds during an experimental infection by Trypanosoma congolense and their biological functions. To this end, whole blood genome-wide transcriptome of three trypanotolerant taurine breeds (N’Dama, Lagune and Baoulé), one susceptible zebu (Zebu Fulani) and one African taurine x zebu admixed breed (Borgou) were profiled by RNA sequencing at four time points, one before and three during infection. As expected, infection had a major impact on cattle blood transcriptome regardless of the breed. The functional analysis of differentially expressed genes over time in each breed confirmed an early activation of the innate immune response, followed by an activation of the humoral response and an inhibition of T cell functions at the chronic stage of infection. More importantly, we highlighted overlooked features, such as a strong disturbance in host metabolism and cellular energy production that differentiates trypanotolerant and trypanosusceptible breeds. N’Dama breed showed the earliest regulation of immune response, associated with a strong activation of cellular energy production, also observed in Lagune, and to a lesser extent in Baoulé. Susceptible Zebu Fulani breed differed from other breeds by the strongest modification in lipid metabolism regulation. Overall, this study provides a better understanding of the biological mechanisms at work during infection, especially concerning the interplay between immunity and metabolism that seems differentially regulated depending on the cattle breeds.

Substantial relation between the bacterial biofilm and oncogenesis progression in host.

Globally, bacteria are well-known microorganisms for bacterial biofilm infection. Bacterial biofilm has generated antibiotic resistance and led the persistent infection. But new complications arise with a biofilm that bacterial biofilm shows the new association with oncogenesis. Some bacteria have a carcinogenic nature at the chronic infection stage like Salmonella Typhi, Helicobacter pylori. Thus, biofilm has a significant role in oncogenesis. Few pieces of evidence also support that the bacterial biofilm has a potential role to develop oncogenesis in the human body. Bacterial biofilm is responsible to induce chronic inflammation and is the main basis for the oncogenesis process. But bacterial biofilm association with the oncogenesis mechanism is unknown yet. This article focuses on the function of bacterial biofilm in tumor formation and the mechanism that encourages the oncogenesis and provide a possible and interesting hypothesis involved in between biofilm and host oncogenesis progression. The discussed relationship will provide a sound direction in the field of oncology and concept may give an informative direction in diagnosis and treatment. Bacterial biofilm behavior could be significantly linked with cancer cell formation. This article attracts the attention of researchers of the field because biofilm mediated oncogenesis further indicate towards an important issue in human health.

Articles of Significant Interest in This Issue.

Helicobacter pylori establishes chronic human stomach infections characterized by persistent inflammation. Previous work had identified a high-inflammation H. pylori mutant lacking the chemoreceptor TlpA. To understand H. pylori inflammation control, Johnson et al. (e00322-22) compared colonization dynamics and host response between the tlpA mutant and the wild type. Both strains caused inflammation at the late, chronic-infection stages, but surprisingly this inflammation fluctuated temporally and was offset in period between the wild type and the tlpA mutant. tlpA mutants also showed high early-infection bacterial numbers. These results suggest that chronic inflammation is more dynamic than previously thought and may be influenced by colonization properties of early infection.

Identification of Molecular Mechanisms Involved in Viral Infection Progression Based on Text Mining: Case Study for HIV Infection.

Viruses cause various infections that may affect human lifestyle for durations ranging from several days to for many years. Although preventative and therapeutic remedies are available for many viruses, they may still have a profound impact on human life. The human immunodeficiency virus type 1 is the most common cause of HIV infection, which represents one of the most dangerous and complex diseases since it affects the immune system and causes its disruption, leading to secondary complications and negatively influencing health-related quality of life. While highly active antiretroviral therapy may decrease the viral load and the velocity of HIV infection progression, some individual peculiarities may affect viral load control or the progression of T-cell malfunction induced by HIV. Our study is aimed at the text-based identification of molecular mechanisms that may be involved in viral infection progression, using HIV as a case study. Specifically, we identified human proteins and genes which commonly occurred, overexpressed or underexpressed, in the collections of publications relevant to (i) HIV infection progression and (ii) acute and chronic stages of HIV infection. Then, we considered biological processes that are controlled by the identified protein and genes. We verified the impact of the identified molecules in the associated clinical study.

Review on Schistosomiasis: Epidemiology and Clinical Manifestation up to Date

Schistosomiasis is a parasite disease that affects both humans and animals and is brought on by the blood flukes of the genus Schistosoma. It is one of the world’s most enduring neglected tropical diseases. Sub-Saharians make up more than 90% of them, and a significant portion of Ethiopians are afflicted and at risk. It spread across the entire nation and was correlated with the rapid development of water resources and population growth. The two species of freshwater snails, Biomphalaria pfeifferi and Biomphalaria sudanica, are responsible for the parasite’s transmission in Ethiopia. Compared to the three primary schistosomes that infect people, Schistosoma mansoni, Schistosoma haematobium, Schistosoma japonicum, Schistosoma intercalatum, and Schistosoma mekongi have less of an epidemiological impact. Geographically, S. haematobium and S. mansoni are more common in Africa than other species. Epidemiological coverage is also influenced by seasonal distributions throughout the postrainy season, as well as the cold and dry seasons. The organs and systems implicated in its pathogenic dissemination include the intestines, urogenital systems, the pulmonary system, the liver, spleen, and the brain. Ecological change and sociocultural influences are risk factors for water contamination. Regarding clinical symptoms, the penetration of cercariae into the dermis, cercarial dermatitis, acute schistosomiasis, and the chronic stage of infection are significant. Mammals and snails serve as the two hosts for the schistosome life cycle. It can be diagnosed through clinical exams and laboratory techniques. Praziquantel can be used to treat this condition, and it can be prevented by taking precautions during ecological shifts that may result in epidemics. Other measures to take include providing clean water, maintaining good hygiene, controlling mosquitoes, and spreading health awareness.

A combined miRNA–piRNA signature in the serum and urine of rabbits infected with Toxoplasma gondii oocysts

BackgroundIncreasing evidence has shown that non-coding RNA (ncRNA) molecules play fundamental roles in cells, and many are stable in body fluids as circulating RNAs. Study on these ncRNAs will provide insights into toxoplasmosis pathophysiology and/or help reveal diagnostic biomarkers.MethodsWe performed a high-throughput RNA-Seq study to comprehensively profile the microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) in rabbit serum and urine after infection with Toxoplasma gondii oocysts during the whole infection process.ResultsTotal RNA extracted from serum and urine samples of acutely infected [8 days post-infection (DPI)], chronically infected (70 DPI) and uninfected rabbits were subjected to genome-wide small RNA sequencing. We identified 2089 miRNAs and 2224 novel piRNAs from the rabbit sera associated with T. gondii infection. Meanwhile, a total of 518 miRNAs and 4182 novel piRNAs were identified in the rabbit urine associated with T. gondii infection. Of these identified small ncRNAs, 1178 and 1317 serum miRNAs and 311 and 294 urine miRNAs were identified as differentially expressed (DE) miRNAs in the acute and chronic stages of infections, respectively. A total of 1748 and 1814 serum piRNAs and 597 and 708 urine piRNAs were found in the acute and chronic infection stages, respectively. Of these dysregulated ncRNAs, a total of 88 common DE miRNAs and 120 DE novel piRNAs were found in both serum and urine samples of infected rabbits.ConclusionsThese findings provide valuable data for revealing the physiology of herbivore toxoplasmosis caused by oocyst infection. Circulating ncRNAs identified in this study are potential novel diagnostic biomarkers for the detection/diagnosis of toxoplasmosis in herbivorous animals.Graphical

Global dynamics of a diffusive SEICR HCV model with nonlinear incidences

To capture the transmission dynamics of hepatitis C virus, we propose and study a reaction–diffusion nonlinear SEICR model, which includes latent, acute, and chronic infection stages. We first establish the well-posedness and boundedness of the model. It is shown the disease-free steady state is globally asymptotically stable if the basic reproduction number R0<1 while the model is uniformly persistent if R0>1. For the special case where the model parameters are spatially homogeneous, we not only derive the explicit expression of R0 but also show that the positive steady state is globally asymptotically stable if R0>1 through the approach of Lyapunov functionals. The feasibility of the theoretical results is demonstrated by numerical simulations. Moreover, we carry out the sensitivity analysis of R0 with respect to the parameters and thus the important parameters significantly influencing the dynamic behaviors are identified.

CircRNA and miRNA expression analysis in livers of mice with Toxoplasma gondii infection.

Toxoplasmosis is an important zoonotic parasitic disease caused by Toxoplasma gondii (T. gondii). However, the functions of circRNAs and miRNAs in response to T. gondii infection in the livers of mice at acute and chronic stages remain unknown. Here, high-throughput RNA sequencing was performed for detecting the expression of circRNAs and miRNAs in livers of mice infected with 20 T. gondii cysts at the acute and chronic stages, in order to understand the potential molecular mechanisms underlying hepatic toxoplasmosis. Overall, 265 and 97 differentially expressed (DE) circRNAs were found in livers at the acute and chronic infection stages in comparison with controls, respectively. In addition, 171 and 77 DEmiRNAs were found in livers at the acute and chronic infection stages, respectively. Functional annotation showed that some immunity-related Gene ontology terms, such as "positive regulation of cytokine production", "regulation of T cell activation", and "immune receptor activity", were enriched at the two infection stages. Moreover, the pathways "Valine, leucine, and isoleucine degradation", "Fatty acid metabolism", and "Glycine, serine, and threonine metabolism" were involved in liver disease. Remarkably, DEcircRNA 6:124519352|124575359 was significantly correlated with DEmiRNAs mmu-miR-146a-5p and mmu-miR-150-5p in the network that was associated with liver immunity and pathogenesis of disease. This study revealed that the expression profiling of circRNAs in the livers was changed after T. gondii infection, and improved our understanding of the transcriptomic landscape of hepatic toxoplasmosis in mice.

Comprehensive analysis of mRNA-lncRNA co-expression profiles in mouse brain during infection with Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular protozoan parasite which seriously threatens the health of domestic animals and humans. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts greater than 200 nucleotides, which are widely involved in transcriptional and epigenetic regulations. However, little is known about the roles of host lncRNAs in the response to T. gondii infections. In this study, using Illumina sequencing technology, we analyzed the expression profiles of mRNAs and lncRNAs in BALB/c mouse brain following infection by T. gondii PRU strain (type II genotype) cysts. The identified differentially expressed (DE) RNAs were subjected to bioinformatics analysis. A total of 2,090 annotated lncRNAs along with 3,577 novel lncRNAs were identified. In the acutely infected mouse brain, a total of 330 mRNAs and 19 lncRNAs were dys-regulated, whereas 136 DE mRNAs and 9 DE lncRNAs were identified in chronically infected mouse brain. GO analysis revealed that these DE mRNAs identified at acute infection stage were involved in immune response, whereas DE mRNAs found at chronic infection stage were mostly enriched in response to protozoan. KEGG analysis showed that DE mRNAs were significantly enriched in disease related pathways. In addition, the putative mRNA-lncRNA co-expression network was constructed, and several hub regulatory RNAs were identified based on the transcriptome data. This study firstly characterized the co-expression profile of mRNAs and lncRNAs in mouse brain infected with T. gondii and provided a framework for further studies of the roles of lncRNAs in host neuropathology during toxoplasmosis progression.

The beta subunit of AMP-activated protein kinase is critical for cell cycle progression and parasite development in Toxoplasma gondii.

Toxoplasma gondii is a widespread eukaryotic pathogen that causes life-threatening diseases in humans and diverse animals. It has a complex life cycle with multiple developmental stages, which are timely adjusted according to growth conditions. But the regulatory mechanisms are largely unknown. Here we show that the AMP-activated protein kinase (AMPK), a key regulator of energy homeostasis in eukaryotes, plays crucial roles in controlling the cell cycle progression and bradyzoite development in Toxoplasma. Deleting the β regulatory subunit of AMPK in the type II strain ME49 caused massive DNA damage and increased spontaneous conversion to bradyzoites (parasites at chronic infection stage), leading to severe growth arrest and reduced virulence of the parasites. Under alkaline stress, all Δampkβ mutants converted to a bradyzoite-like state but the cell division pattern was significantly impaired, resulting in compromised parasite viability. Moreover, we found that phosphorylation of the catalytic subunit AMPKα was greatly increased in alkaline stressed parasites, whereas AMPKβ deletion mutants failed to do so. Phosphoproteomics found that many proteins with predicted roles in cell cycle and cell division regulation were differentially phosphorylated after AMPKβ deletion, under both normal and alkaline stress conditions. Together, these results suggest that the parasite AMPK has critical roles in safeguarding cell cycle progression, and guiding the proper exist of the cell cycle to form mature bradyzoites when the parasites are stressed. Consistent with this model, growth of parasites was not significantly altered when AMPKβ was deleted in a strain that was naturally reluctant to bradyzoite development.

Microglial STAT1-sufficiency is required for resistance to toxoplasmic encephalitis.

Toxoplasma gondii is a ubiquitous intracellular protozoan parasite that establishes a life-long chronic infection largely restricted to the central nervous system (CNS). Constant immune pressure, notably IFN-γ-STAT1 signaling, is required for preventing fatal pathology during T. gondii infection. Here, we report that abrogation of STAT1 signaling in microglia, the resident immune cells of the CNS, is sufficient to induce a loss of parasite control in the CNS and susceptibility to toxoplasmic encephalitis during the early stages of chronic infection. Using a microglia-specific genetic labeling and targeting system that discriminates microglia from blood-derived myeloid cells that infiltrate the brain during infection, we find that, contrary to previous in vitro reports, microglia do not express inducible nitric-oxide synthase (iNOS) during T. gondii infection in vivo. Instead, transcriptomic analyses of microglia reveal that STAT1 regulates both (i) a transcriptional shift from homeostatic to "disease-associated microglia" (DAM) phenotype conserved across several neuroinflammatory models, including T. gondii infection, and (ii) the expression of anti-parasitic cytosolic molecules that are required for eliminating T. gondii in a cell-intrinsic manner. Further, genetic deletion of Stat1 from microglia during T. gondii challenge leads to fatal pathology despite largely equivalent or enhanced immune effector functions displayed by brain-infiltrating immune populations. Finally, we show that microglial STAT1-deficiency results in the overrepresentation of the highly replicative, lytic tachyzoite form of T. gondii, relative to its quiescent, semi-dormant bradyzoite form typical of chronic CNS infection. Our data suggest an overall protective role of CNS-resident microglia against T. gondii infection, illuminating (i) general mechanisms of CNS-specific immunity to infection (ii) and a clear role for IFN-STAT1 signaling in regulating a microglial activation phenotype observed across diverse neuroinflammatory disease states.

Interference between miR-21/PTEN/E-Cadherin and Epithelial-Mesenchymal Transition in Various Stages of Chronic HCV Infection

Interference between miR-21/PTEN/E-Cadherin and Epithelial-Mesenchymal Transition in Various Stages of Chronic HCV Infection

335.2: Long-term Outcomes of Liver Transplantation Using Grafts From Donors With Active Hepatitis B virus Replication: A Multicenter Cohort Study

Background: Liver grafts from donors with hepatitis B infection contributed to expanding the donor pool under the Hepatitis B immunoglobulin (HBIG) and antiviral agents (NA: Nucleos(t)ide analogs) in the hepatitis B virus (HBV) endemic area. The purpose of this study is to describe the long-term outcome of liver transplantation (LT) using grafts from donors with active and chronic hepatitis B virus infection. Methods: Between January 2000 and April 2019, 2260 liver transplants (LTs) were performed at Seoul National University (SNU) Hospital, SNU Bundang Hospital (SNUBH), and Seoul Metropolitan Government-SNU Boramae Hospital. Twenty-six (1.2%) grafts from donors with HBsAg (+), HBeAb (+), or HBV DNA (+) were classified as active and chronic HBV hepatitis grafts and retrospectively reviewed. The demographics of donors and recipients, as well as the outcomes of transplantation, were analyzed. HBV reactivation has been defined as an increase in viral DNA in HBsAg (+) grafts and seroconversion to HBsAg positive grafts in chronic hepatitis grafts. Additionally, we used the chronic HBV infection stage to evaluate and manage recipients who received HBV-infected grafts. Results: Sixteen LT were performed on deceased donors using active HBsAg (+) grafts. Ten living donor LT were performed using inactive HBV grafts; eight patients with inactive hepatitis; HBsAg (-), HBcAb (+), and HBV DNA (+), and two patients with chronic HBV hepatitis with seroconversion; HBsAg (-), HBsAb (+), and HBeAg (+) (Figure 1). The recipients were aged 59.0 ± 10.3 years and had a MELD score of 19.9 ± 8.4. The mean duration of follow-up was 82.6 ± 60.1 months. Depending on the donor and recipient’s serology, NA and HBIG were administered during the perioperative period. Deaths (n=8) occurred between 2.0 and 47.3 months following LT. All deaths were reported in DDLT. When compared with LT using grafts without HBV, LT using HBV infected grafts did not show any significant difference in patient survival (30.8% vs. 18.6%, p=0.247) (Figure 2). The most common causes of death were infection (n=4) and HCC recurrence (n=3). All recurred HCC patients died of cancer. HBV reactivation was identified in 1 patient but resolved spontaneously without additional management. All 10 LDLT recipients survived and were in good condition during follow-up. Survivors were in inactive or resolved status for HBV infection under the HBIG and NA. No graft failure was observed. Fourteen patients followed-up more than 5 years were stable and no increase in HCC recurrence rate was observed 5 years after transplantation. Conclusion: Considering their long-term outcomes, liver grafts with active and chronic HBV infection can be safely used for LT in HBV endemic area.