Biology subjects

Najera, I.

Publications and source records attributed to Najera, I..

4 recordsLinked to original sources

bioRxiv2023

Patient phenotypes and their relation to TNFα signaling and immune cell composition in critical illness and autoimmune disease

RationaleTNF inhibitors have shown promise in reducing mortality in hospitalized COVID-19 patients; one hypothesis explaining the limited clinical efficacy is patient heterogeneity in the TNF pathway. MethodsWe evaluated the effect of TNF inhibitors in a mouse model of LPS-induced acute lung injury. Using machine learning we attempted predictive enrichment of TNF signaling in patients with either ARDS or sepsis. We examined biological factors that drive heterogeneity in host responses to critical infection and their relation to clinical outcomes. ResultsIn mice, LPS induced TNF-dependent neutrophilia, alveolar permeability and endothelial injury. In humans, TNF pathway activation was significantly increased in peripheral blood of patients with critical illnesses and associated with the presence of mature neutrophils across critical illnesses and several autoimmune conditions. Machine learning using a gene signature separated patients into 5 phenotypes; one was a hyper-inflammatory, interferon-associated phenotype enriched for increased TNF pathway activation and conserved across critical illnesses and autoimmune diseases. Cell subset profiles segregated severely ill patients into neutrophil-subset-dependent groups that were enriched for disease severity, demonstrating the importance of neutrophils in the immune response in critical illness. ConclusionsTNF signaling and mature neutrophils are associated with a hyper-inflammatory phenotype of patients, shared across critical illness and autoimmune disease. This phenotyping provides a personalized medicine hypothesis to test anti-TNF therapy in severe respiratory illness. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=103 SRC="FIGDIR/small/564631v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@1e25724org.highwire.dtl.DTLVardef@c708bcorg.highwire.dtl.DTLVardef@10e7531org.highwire.dtl.DTLVardef@3014b8_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

bioRxiv2023

Class A capsid assembly modulator apoptotic elimination of hepatocytes with high HBV core antigen level in vivo is dependent on de novo core protein translation

Background and aimsCapsid assembly (CA) is a critical step in the hepatitis B virus (HBV) life cycle, mediated by the viral core protein. CA is the target for various new anti-viral candidate therapeutics known as capsid assembly modulators (CAMs) of which the CAM-aberrant (CAM-A) class induces aberrant shaped core protein structures and lead to hepatocyte cell death. The aim of the studies was to identify the mechanism of action of the CAM-A modulators leading to HBV infected hepatocyte elimination. MethodsThe CAM-A mediated mechanism of HBsAg reduction was evaluated in vitro in a stable HBV replicating cell line and in vivo in AAV-HBV transduced C57BL/6, C57BL/6 SCID and HBV-infected chimeric mice with humanized livers. ResultsIn vivo treatment with CAM-A modulators induced pronounced reductions in HBe- and HBsAg which were associated with a transient increase in ALT. Both HBs- and HBeAg reduction and ALT increase were delayed in C57BL/6 SCID and chimeric mice, suggesting that adaptive immune responses may indirectly contribute to this phenotype. However, depletion of CD8+ T-cells in transduced wild-type mice did not have a negative impact on antigen reduction, indicating that CD8+ T-cell responses are not essential. Coinciding with the transient ALT elevation in AAV-HBV transduced mice, we observed a transient increase in markers related to endoplasmic reticulum stress and apoptosis as well as cytokines related to apoptosis pathways, followed by the detection of a proliferation marker. Pathway enrichment analysis of microarray data revealed that antigen presentation pathway (MHC-I) was upregulated, overlapping with observed apoptosis. Combination treatment with HBV-specific siRNA demonstrated that CAM-A mediated HBsAg reduction is dependent on de novo core protein translation and that the effect is dependent on high levels of core protein expression, which will likely focus the CHB sub-population that could respond. ConclusionCAM-A treatment eradicates HBV infected hepatocytes with high core protein levels through the induction of apoptosis a promising approach as part of a regimen to achieve functional cure. Lay summaryTreatment with hepatitis B virus (HBV) capsid assembly modulators that induce the formation of aberrant HBV core protein structures (CAM-A) leads to programmed cell death, apoptosis, of HBV-infected hepatocytes and subsequent reduction of HBV antigens, which differentiates CAM-A from other CAMs. The effect is dependent on the de novo synthesis and high levels of core protein.

microbiology↗

bioRxiv2023

Sustained liver HBsAg loss and clonal T and B cell expansion upon therapeutic DNA vaccination require low HBsAg levels

Background & AimsSuppression of HBV DNA, inhibition of HBsAg production and therapeutic vaccination to reverse HBV-specific T-cell exhaustion in chronic HBV patients are likely required to achieve functional cure. In the AAV-HBV mouse model, therapeutic vaccination can be effective in clearing HBsAg when hepatitis B surface (HBsAg) levels are low. The factor(s) required for mounting an effective immune control of HBV infection are unclear. Using a single-cell approach, we investigated the liver immune environment in the context of different levels of HBsAg as well as upon sustained HBsAg loss through treatment with an HBV specific GalNAc-siRNA followed by therapeutic vaccination. MethodsC57BL/6 mice were transduced with a range of rAAV-HBV DNA to express different HBsAg levels. Mice were treated with GalNAc-siRNA targeting HBV transcripts to lower the HBsAg levels and then vaccinated 4 times with a DNA vaccine encoding HBV Core, Pol and Surface. We used single-cell RNA-sequencing on homogenised liver resident cells, paired with single-cell V(D)J receptor sequencing to understand the changes in the liver immune microenvironment. ResultsTreatment with GalNAc-HBV siRNA followed by therapeutic vaccination, achieved a sustained HBsAg loss in all mice. This was accompanied by an induction of CD4 follicular helper T-cell responses, polyclonal activation of CD8 T-cells in the liver and clonal expansion of plasma cells that were responsible for antibody production. ConclusionsThis study provides novel insight into the immune changes in the liver at the single-cell level, highlighting the correlation between the induced reduction in HBsAg levels and the clonal expansion of CD4 follicular helper T-cells, CD8 cytotoxic T-cells, plasma cells, and ISG-producing neutrophils in the liver upon HBV siRNA and subsequent therapeutic vaccine treatment. Lay SummaryChronic hepatitis B infection is characterized by a complex interplay between immune responses and viral replication in the liver. To achieve functional cure a combination of different treatments is likely required. In this study single-cell approach was used to understand the liver microenvironment in the context of different HBsAg levels followed by therapeutic vaccination in AAV-HBV mouse model and to identify key factors required to achieve functional cure. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/556204v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@5776a4org.highwire.dtl.DTLVardef@2e1b9forg.highwire.dtl.DTLVardef@1179a2eorg.highwire.dtl.DTLVardef@8b801d_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIAAV-HBV transduced mice sequentially treated with GalNAc-siRNA and therapeutic vaccine showed sustained HBsAg loss. C_LIO_LIThe sustained HBsAg loss correlates with increased proportion and clonal expansion of CD4 follicular helper T-cells, CD8 cytotoxic T-cells, plasma cells, and ISG producing neutrophils in the liver. C_LIO_LIBaseline levels of HBsAg are important to determine outcome of therapeutic vaccination in mice. C_LI

immunology↗

bioRxiv2023

AAV-HBV mouse model replicates immune exhaustion patterns of chronic HBV patients at single-cell level

Background and AimsUnresolved hepatitis B virus (HBV) infection leads to a progressive state of immune exhaustion that impairs resolution of infection, leading to chronic infection (CHB). The immune-competent AAV-HBV mouse is a common HBV preclinical immune competent model, though a comprehensive characterization of the liver immune microenvironment and its translatability to human infection is still lacking. We investigated the intrahepatic immune profile of the AAV-HBV mouse model at a single-cell level and compared with data from CHB patients in immune tolerant (IT) and immune active (IA) clinical stages. MethodsImmune exhaustion was profiled through an iterative subclustering approach for cell-typing analyses of single-cell RNA-sequencing data in CHB donors and compared to the AAV-HBV mouse model 24-weeks post-transduction to assess its translatability. This was validated using an exhaustion flow cytometry panel at 40 weeks post-transduction. ResultsUsing single-cell RNA-sequencing, CD8 pre-exhausted T-cells with self-renewing capacity (TCF7+), and terminally exhausted CD8 T-cells (TCF7-) were detected in the AAV-HBV model. These terminally exhausted CD8 T-cells (expressing Pdcd1, Tox, Lag3, Tigit) were significantly enriched versus control mice and independently identified through flow cytometry. Importantly, comparison to CHB human data showed a similar exhausted CD8 T-cell population in IT and IA donors, but not in healthy individuals. ConclusionsLong term high titer AAV-HBV mouse liver transduction led to T-cell exhaustion, as evidenced by expression of classical immune checkpoint markers at mRNA and protein levels. In both IT and IA donors, a similar CD8 exhausted T-cell population was identified, with increased frequency observed in IA donors. These data support the use of the AAV-HBV mouse model to study T-cell exhaustion in HBV infection and the effect of immune-based therapeutic interventions. Lay SummaryThe AAV-HBV mouse model is used as a research tool to study hepatitis B infection. In this study we evaluated the translation value from mouse to human with regards to T-cell exhaustion. HighlightsO_LIAAV-HBV mice transduced with a high titer vector showed presence of CD8 exhausted T-cells after 24 weeks. C_LIO_LIHigh titer transduced mice, but not lower titer show increased expression of LAG-3, TOX, TIM-3 and TIGIT in CD8 T-cells. PD-1 was increased in CD8 T-cells, independent of HBV transduction titer. C_LIO_LIA similar exhausted CD8 T-cell population could be found in chronic HBV donors, but not in healthy individuals. C_LI Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=75 SRC="FIGDIR/small/552328v1_ufig1.gif" ALT="Figure 1"> View larger version (14K): org.highwire.dtl.DTLVardef@17db34dorg.highwire.dtl.DTLVardef@186a0b1org.highwire.dtl.DTLVardef@19fd39borg.highwire.dtl.DTLVardef@1fd9f64_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗