Polyinosinic-polycytidylic Acid Research Articles

Abstract 1413: BRCA1 loss is synthetic lethal with double stranded RNA: A genome wide CRISPR screen to identify mechanisms of RNASEL independent death

Abstract Double-stranded RNAs (dsRNAs) are potent immunostimulatory nucleic acids of viral origin but also physiologically produced by mammalian cells. Recent studies demonstrated that elevating dsRNA levels, either exogenously through dsRNA mimetics like Polyinosinic-polycytidylic acid (pI:C) or endogenously through epigenetic modulation of retroviral elements, can elicit anticancer effects. In response to dsRNA, cells elicit a dual response consisting in Interferon (IFN) production and translational shutdown associated, in some cells, with cell death. These two responses are linked in a feed-forward loop in which induced cytokines themselves enhance dsRNA sensing by the death-inducing pathway, complicating our understanding of the cell-intrinsic mechanisms at play. The 2,5-oligoadenylate synthetase (OAS)-RNASEL system is widely thought to be the main responsible for dsRNA-induced cell death, but it remains unclear how its activity leads to cell death.To elucidate these mechanisms, we decided to minimize the impact of interferon modulation by studying dsRNA-induced death in interferon-saturated conditions. RNASEL-KO A549 cells were, as expected, refractory to IFN+pI:C induced cell death; however, inhibiting protein synthesis or RNA transcription with Cycloheximide (CHX) or Actinomycin D (ActD) abolished the need for RNASEL causing RNASEL-KO cells to undergo apoptosis, although CHX/ActD alone had no effect. In addition, HT-29 cells revealed no clear dependence on RNASEL for dsRNA-induced cell death. Transient ablation through siRNA showed that this novel death-inducing pathway is independent of other canonical dsRNA sensors such as RIG-I, MDA5 and PKR. We then performed a genome-wide CRISPR screen for factors involved in dsRNA-induced death in our interferon-saturated conditions in HT29 cells. Pathway enrichment analysis of screen hits revealed that RNA surveillance, RNA Polymerase II Transcription Initiation, Mitochondrial translation and respiratory chain and DNA Repair genes have a protective role against dsRNA increase. In particular, we validated the synthetic lethality of IFN+pI:C with BRCA1 by CRISPR. Ongoing research is aimed at validating this interaction in vivo models.Our work shed light on potential new mechanisms involved in dsRNA dependent cell death, revealing a connection with DNA damage and BRCA1. If confirmed, these findings may pave the way for the use of dsRNA mimetics, possibly in conjunction with immune checkpoint inhibitors, in the treatment of BRCA1-mutated tumors. Citation Format: Deborah Trastulli, Gianluca Vozza, Veronica Pinamonti, Luca Mazzarella. BRCA1 loss is synthetic lethal with double stranded RNA: A genome wide CRISPR screen to identify mechanisms of RNASEL independent death [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1413.

Amiodarone inhibits the Toll-like receptor 3-mediated nuclear factor κB signaling pathway by blocking organelle acidification

Toll-like receptor (TLR) agonists or pro-inflammatory cytokines converge to activate the nuclear factor κB (NF-κB) signaling pathway, which provokes inflammatory responses. In the present study, we identified amiodarone hydrochloride as a selective inhibitor of the TLR3-mediated NF-κB signaling pathway by screening the RIKEN NPDepo Chemical Library. In human umbilical vein endothelial cells (HUVEC), amiodarone selectively inhibited the expression of intercellular adhesion molecule-1 (ICAM-1) induced by polyinosinic-polycytidylic acid (Poly(I:C)), but not tumor necrosis factor-α, interleukin-1α, or lipopolysaccharide. In response to a Poly(I:C) stimulation, amiodarone at 20 μM reduced the up-regulation of mRNA expression encoding ICAM-1, vascular cell adhesion molecule-1, and E-selectin. The nuclear translocation of the NF-κB subunit RelA was inhibited by amiodarone at 15–20 μM in Poly(I:C)-stimulated HUVEC. Amiodarone diminished the fluorescent dots of LysoTracker® Red DND-99 scattered over the cytoplasm of HUVEC. Therefore, the present study revealed that amiodarone selectively inhibited the TLR3-mediated NF-κB signaling pathway by blocking the acidification of intracellular organelles.

Monophosphoryl lipid A and poly I:C combination enhances immune responses of equine influenza virus vaccine

Equine influenza is a contagious respiratory disease caused by H3N8 type A influenza virus. Vaccination against equine influenza is conducted regularly; however, infection still occurs globally because of the short immunity duration and suboptimal efficacy of current vaccines. Hence the objective of this study was to investigate whether an adjuvant combination can improve immune responses to equine influenza virus (EIV) vaccines. Seventy-two mice were immunized with an EIV vaccine only or with monophosphoryl lipid A (MPL), polyinosinic-polycytidylic acid (Poly I:C), or MPL + Poly I:C. Prime immunization was followed by boost immunization after 2 weeks. Mice were euthanized at 4, 8, and 32 weeks post-prime immunization, respectively. Sera were collected to determine humoral response. Bone marrow, spleen, and lung samples were harvested to determine memory cell responses, antigen-specific T-cell proliferation, and lung viral titers. MPL + Poly I:C resulted in the highest IgG, IgG1, and IgG2a antibodies and hemagglutination inhibition titers among the groups and sustained their levels until 32 weeks post-prime immunization. The combination enhanced memory B cell responses in the bone marrow and spleen. At 8 weeks post-prime immunization, the combination induced higher CD8+ central memory T cell frequencies in the lungs and CD8+ central memory T cells in the spleen. In addition, the combination group exhibited enhanced antigen-specific T cell proliferation, except for CD4+ T cells in the lungs. Our results demonstrated improved immune responses when using MPL + Poly I:C in EIV vaccines by inducing enhanced humoral responses, memory cell responses, and antigen-specific T cell proliferation.

TMEM2 suppresses TLR3-mediated IFN-β/ISG56/CXCL10 expression in BEAS-2B bronchial epithelial cells.

Bronchial epithelial cells are at the front line of viral infections. Toll-like receptor 3 (TLR3) cascade causes the expression of interferon (IFN)-β and IFN-stimulated genes (ISGs), which in turn induce an antiviral response. Members of the transmembrane protein (TMEM) family are expressed in various cell types. Although the prognostic value of TMEM2 in various cancers has been reported, its association with infectious diseases remains unknown. In this study, we investigated the effects of TMEM2 on antiviral immunity in BEAS-2B bronchial epithelial cells. TMEM2 protein was found in the cytoplasm of normal human bronchial epithelial cells and differed between organs using immunohistochemistry. Cultured BEAS-2B cells were transfected with TMEM2 siRNA, followed by administration of TLR3 ligand polyinosinic-polycytidylic acid (poly IC) or recombinant human (r(h)) IFN-β. The expression of TMEM2, IFN-β, ISG56, C-X-C motif chemokine ligand 10 (CXCL10) and hyaluronan were evaluated appropriately by western blotting, quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. TMEM2 expression was not altered by poly IC stimulation. Knockdown of TMEM2 increased poly IC-induced expression of IFN-β, CXCL10, and ISG56, while IFN-β-induced expression of ISG56 and CXCL10 were not changed by TMEM2 knockdown. The hyaluronan concentration in the medium was decreased by either TMEM2 knockdown or poly IC, but additive or synergistic effects were not observed. TMEM2 knockdown enhanced TLR3-mediated IFN-β, CXCL10, and ISG56 expression in BEAS-2B cells. This implies that TMEM2 suppresses antiviral immune responses and prevents tissue injury in bronchial epithelial cells.

Cecropin A: investigation of a host defense peptide with multifaceted immunomodulatory activity in a chicken hepatic cell culture.

Host defense peptides (HDPs) are increasingly referred to as promising candidates for the reduction of the use of conventional antibiotics, thereby combating antibiotic resistance. As HDPs have been described to exert various immunomodulatory effects, cecropin A (CecA) appears to be a potent agent to influence the host inflammatory response. In the present study, a chicken primary hepatocyte-non-parenchymal cell co-culture was used to investigate the putative immunomodulatory effects of CecA alone and in inflammatory conditions evoked by polyinosinic-polycytidylic acid (Poly I:C). To examine the viability of the cells, the extracellular lactate dehydrogenase (LDH) activity was determined by colorimetric assay. Inflammatory markers interleukin (IL)-8 and transforming growth factor-ß1 (TGF-ß1) were investigated using the ELISA method, whereas concentrations of IL-6, IL-10, and interferon-γ (IFN-γ) were assayed by Luminex xMAP technology. Extracellular H2O2 and malondialdehyde levels were measured by fluorometric and colorimetric methods, respectively. Results of the lower concentrations suggested the safe application of CecA; however, it might contribute to hepatic cell membrane damage at its higher concentrations. We also found that the peptide alleviated the inflammatory response, reflected by the decreased production of the pro-inflammatory IL-6, IL-8, and IFN-γ. In addition, CecA diminished the levels of anti-inflammatory IL-10 and TGF-ß1. The oxidative markers measured remained unchanged in most cases of CecA exposure. CecA displayed a multifaceted immunomodulatory but not purely anti-inflammatory activity on the hepatic cells, and might be suggested to maintain the hepatic inflammatory homeostasis in Poly I:C-triggered immune response. To conclude, our study suggests that CecA might be a promising molecule for the development of new immunomodulatory antibiotic-substitutive agents in poultry medicine; however, there is still a lot to clarify regarding its cellular effects.

Toll-like receptor 3 signaling drives enteric glial cells against dextran sulfate sodium-induced colitis in mice.

The activation of toll-like receptor 3 (TLR3) has been reported to attenuate astrocytes injury in central nervous system, but its effect on enteric glial cells (EGCs) remains unknown. Here, we confirmed that the residence of EGCs was regulated by TLR3 agonist (polyinosinic-polycytidylic acid, PIC) or TLR3/dsRNA complex inhibitor in dextran sulfate sodium (DSS)-induced mice. In vitro, TLR3 signaling prevented apoptosis in EGCs and drove the secretion of EGCs-derived glial cell line-derived neurotrophic factor, 15-hydroxyeicosatetraenoic acid and S-nitrosoglutathione. PIC preconditioning enhanced the protective effects of EGCs against the dysfunction of intestinal epithelial barrier and the development of colitis in DSS-induced mice. Interestingly, PIC stimulation also promoted the effects of EGCs on converting macrophages to an M2-like phenotype and regulating the levels of inflammatory cytokines, including IL-1β, TNF-α and IL-10, in DSS-induced mice. These findings imply that TLR3 signaling in EGCs may provide a potential target for the prevention and treatment of colitis.

Dysfunctional neutrophil type 1 interferon responses in preschool children with recurrent wheezing and IL-4–mediated aeroallergen sensitization

BackgroundThe innate mechanisms associated with viral exacerbations in preschool children with recurrent wheezing are not understood. ObjectiveWe assessed differential gene expression in blood neutrophils from preschool children with recurrent wheezing, stratified by aeroallergen sensitization, at baseline and after exposure to polyinosinic-polycytidylic acid (poly(I:C)). We also examined whether poly(I:C)-stimulated blood neutrophils influenced airway epithelial gene expression. MethodsBlood neutrophils were purified and cultured overnight with poly(I:C) and underwent next-generation sequencing with Reactome pathway analysis. Primary human small airway epithelial cells were treated with poly(I:C)-treated neutrophil culture supernatants and were analyzed for Type 1 interferon gene expression with a targeted array. Symptoms and exacerbations were assessed in participants over 12 months. Results436 genes were differently expressed in neutrophils from children with versus without aeroallergen sensitization at baseline, with significant downregulation of Type 1 interferons. These Type 1 interferons were significantly upregulated in sensitized children after poly(I:C) stimulation. Confirmatory experiments demonstrated similar upregulation of Type 1 interferons in IL-4 treated neutrophils stimulated with poly(I:C). Poly(I:C)-treated neutrophil supernatants from children with aeroallergen sensitization also induced a Type 1 interferon response in epithelial cells. Children with aeroallergen sensitization also had higher symptom scores during exacerbations and these symptom differences persisted for three days after prednisolone treatment. ConclusionsType 1 interferon responses are dysregulated in preschool children with aeroallergen sensitization, which is in turn associated with exacerbation severity. Given the importance of Type 1 interferon signaling in viral resolution, additional studies of neutrophil Type 1 interferon responses are needed in this population.

Examining rainbow trout vig-3 expression patterns in vitro following treatment with type I IFN, poly IC or viral infection

Interferon-stimulated genes (ISGs) are key mediators of antiviral immunity. Investigating ISGs can help create novel therapeutics to increase survival rates of farmed fish and aid in protection against pathogens. The current study investigated the induction of one such ISG, viral hemorrhagic septicemia (VHSV) – induced gene 3 (vig-3), also known as ISG15 in mammals and other fish species. Vig-3 is one of many rainbow trout ISGs whose expression patterns, induction, and role remain relatively unknown. In this study, vig-3 transcript expression was identified in a panel of tissues from healthy rainbow trout. Vig-3 transcripts were upregulated in response to recombinant type I interferon (IFN-I) treatment in rainbow trout gonadal cells (RTG-2). Vig-3 transcript and protein levels were upregulated overtime following treatment with a double-stranded (ds)RNA molecule, polyinosinic: polycytidylic acid (poly IC), and infection with two viruses, infectious pancreatic necrosis virus (IPNV) and viral hemorrhagic septicemia virus (VHSV) in two rainbow trout cell lines, RTG-2 and RTgill-W1. Vig-3 transcript expression kinetics positively corelated with viral replication kinetics. Western blot analysis demonstrated evidence of protein ISGylation, a unique feature of vig-3. Vig-3′s cellular localization was assessed using immunocytochemistry following viral infection. Vig-3 expression was cytoplasmic and increased in quantity over time, upon treatment with poly IC, or infection with IPNV or VHSV. These findings improve our understanding of the rainbow trout innate immune system and could aid in the production of fish antiviral therapeutics in the future.

RWTC-MBTA Vaccine Induces Potent Adaptive Immune Responses Against Glioblastomas via Dynamic Activation of Dendritic Cells.

Despite strides in immunotherapy, glioblastoma multiforme (GBM) remains challenging due to low inherent immunogenicity and suppressive tumor microenvironment. Converting "cold" GBMs to "hot" is crucial for immune activation and improved outcomes. This study comprehensively characterized a therapeutic vaccination strategy for preclinical GBM models. The vaccine consists of Mannan-BAM-anchored irradiated whole tumor cells, Toll-like receptor ligands [lipoteichoic acid (LTA), polyinosinic-polycytidylic acid (Poly (I:C)), and resiquimod (R-848)], and anti-CD40 agonistic antibody (rWTC-MBTA). Intracranial GBM models (GL261, SB28 cells) are used to evaluate the vaccine efficacy. A substantial number of vaccinated mice exhibited complete regression of GBM tumors in a T-cell-dependent manner, with no significant toxicity. Long-term tumor-specific immune memory is confirmed upon tumor rechallenge. In the vaccine-draining lymph nodes of the SB28 model, rWTC-MBTA vaccination triggered a major rise in conventional dendritic cell type 1 (cDC1) 12h post-treatment, followed by an increase in conventional dendritic cell type 2 (cDC2), monocyte-derived dendritic cell (moDC), and plasmacytoid dendritic cell (pDC) on Day 5 and Day 13. Enhanced cytotoxicity of CD4+ and CD8+ T cells in vaccinated mice is verified in co-culture with tumor cells. Analyses of immunosuppressive signals (T-cell exhaustion, myeloid-derived suppressor cells (MDSC), M2 macrophages) in the GBM microenvironment suggest potential combinations with other immunotherapies for enhanced efficacy. In conclusion, the authors findings demonstrate that rWTC-MBTA induces potent and long-term adaptive immune responses against GBM.

Possible involvement of DExD/H box helicase 60 in synovial inflammation of rheumatoid arthritis: role of toll-like receptor 3 signaling.

Innate immunity is known to be implicated in the etiology of synovitis in rheumatoid arthritis (RA). However, details of the molecular mechanisms have not been fully clarified. DExD/H-box helicase 60 (DDX60), a putative RNA helicase, is of consequence in anti-viral innate immune reactions followed by inflammation. Although DDX60 is involved in the pathogenesis of autoimmune diseases such as systemic lupus nephritis, the role of DDX60 in RA has not been elucidated. The objective of this study was to examine the expression and the role of DDX60 in RA synovial inflammation. DDX60 protein expression was investigated by immunohistochemistry in synovial tissues resected from 4 RA and 4 osteoarthritis (OA) patients. We found that synovial DDX60 expression was more intense in RA than in OA. Treatment of human rheumatoid fibroblast-like synoviocytes in culture with polyinosinic-polycytidylic acid, a Toll-like receptor 3 (TLR3) ligand, increased DDX60 protein and mRNA expression. A knockdown experiment of DDX60 using RNA interference revealed a decrease in the expression of poly IC-induced C-X-C motif chemokine ligand 10 (CXCL10) which induces lymphocyte chemotaxis. The synovial DDX60 was more expressed in RA patients than in OA. In human RFLS, DDX60 stimulated by TLR3 signaling affected CXCL10 expression. DDX60 may contribute to synovial inflammation in RA.

Inter-alpha-trypsin inhibitor (IαI) and hyaluronan modifications enhance the innate immune response to influenza virus in the lung

The inter-alpha-trypsin inhibitor (IαI) complex is composed of the bikunin core protein with a single chondroitin sulfate (CS) attached and one or two heavy chains (HCs) covalently linked to the CS chain. The HCs from IαI can be transferred to hyaluronan (HA) through a TNFα-stimulated gene-6 (TSG-6) dependent process to form an HC•HA matrix. Previous studies reported increased IαI, HA, and HC•HA complexes in mouse bronchoalveolar lavage fluid (BALF) post-influenza infection. However, the expression and incorporation of HCs into the HA matrix of the lungs during the clinical course of influenza A virus (IAV) infection and the biological significance of the HC•HA matrix are poorly understood. The present study aimed to better understand the composition of HC•HA matrices in mice infected with IAV and how these matrices regulate the host pulmonary immune response. In IAV infected mice bikunin, HC1–3, TSG-6, and HAS1–3 all show increased gene expression at various times during a 12-day clinical course. The increased accumulation of IαI and HA was confirmed in the lungs of infected mice using immunohistochemistry and quantitative digital pathology. Western blots confirmed increases in the IαI components in BALF and lung tissue at 6 days post-infection (dpi). Interestingly, HCs and bikunin recovered from BALF and plasma from mice 6 dpi with IAV, displayed differences in the HC composition by Western blot analysis and differences in bikunin's CS chain sulfation patterns by mass spectrometry analysis. This strongly suggests that the IαI components were synthesized in the lungs rather than translocated from the vascular compartment. HA was significantly increased in BALF at 6 dpi, and the HA recovered in BALF and lung tissues were modified with HCs indicating the presence of an HC•HA matrix. In vitro experiments using polyinosinic-polycytidylic acid (poly(I:C)) treated mouse lung fibroblasts (MLF) showed that modification of HA with HCs increased cell-associated HA, and that this increase was due to the retention of HA in the MLF glycocalyx. In vitro studies of leukocyte adhesion showed differential binding of lymphoid (Hut78), monocyte (U937), and neutrophil (dHL60) cell lines to HA and HC•HA matrices. Hut78 cells adhered to immobilized HA in a size and concentration-dependent manner. In contrast, the binding of dHL60 and U937 cells depended on generating a HC•HA matrix by MLF. Our in vivo findings, using multiple bronchoalveolar lavages, correlated with our in vitro findings in that lymphoid cells bound more tightly to the HA-glycocalyx in the lungs of influenza-infected mice than neutrophils and mononuclear phagocytes (MNPs). The neutrophils and MNPs were associated with a HC•HA matrix and were more readily lavaged from the lungs. In conclusion, this work shows increased IαI and HA accumulation and the formation of a HC•HA matrix in mouse lungs post-IAV infection. The formation of HA and HC•HA matrices could potentially create specific microenvironments in the lungs for immune cell recruitment and activation during IAV infection.

Bovine serum albumin nanoparticles containing Poly (I:C) can enhance the neutralizing antibody response induced by envelope protein of Orthoflavivirus zikaense

Since the Orthoflavivirus zikaense (ZIKV) has been considered a risk for Zika congenital syndrome development, developing a safe and effective vaccine has become a high priority. Numerous research groups have developed strategies to prevent ZIKV infection and have identified the domain III of the ZIKV envelope protein (zEDIII) as a promising target. Subunit antigens are often poorly immunogenic, necessitating the use of adjuvants and/or delivery systems to induce optimal immune responses. The subject of nanotechnology has substantial expansion in recent years in terms of research and applications. Nanoparticles could be used as drug delivery systems and to increase the immunogenicity and stability of a given antigen. This work aims to characterize and validate the potential of a vaccine formulation composed of domain zEDIII and bovine serum albumin nanoparticles containing polyinosinic-polycytidylic acid (NPPI). NPPI were uptake in vitro by immature bone marrow dendritic cells and histological analysis of the skin of mice treated with NPPI showed an increase in cellularity. Immunization assay showed that mice immunized with zEDIII in the presence of NPPI produced neutralizing antibodies. Through the passive transfer of sera from immunized mice to ZIKV-infected neonatal mice, it was demonstrated that these antibodies provide protection, mitigating weight loss, clinical or neurological signs induced by infection, and significantly increased survival rates. Protection was further substantiated by the reduction in the number of viable infectious ZIKV, as well as a decrease in inflammatory cytokines and tissue alterations in the brains of infected mice. Taken together, data presented in this study shows that NPPI + zEDIII is a promising vaccine candidate for ZIKV.

Mitochondrial Reactive Oxygen Species in TRIF-Dependent Toll-like Receptor 3 Signaling in Bronchial Epithelial Cells against Viral Infection.

Toll-like receptor 3 (TLR3) plays an important role in double-stranded RNA recognition and triggers the innate immune response by acting as a key receptor against viral infections. Intracellular reactive oxygen species (ROS) are involved in TLR3-induced inflammatory responses during viral infections; however, their relationship with mitochondrial ROS (mtROS) remains largely unknown. In this study, we show that polyinosinic-polycytidylic acid (poly(I:C)), a mimic of viral RNA, induced TLR3-mediated nuclear factor-kappa B (NF-κB) signaling pathway activation and enhanced mtROS generation, leading to inflammatory cytokine production. TLR3-targeted small interfering RNA (siRNA) and Mito-TEMPO inhibited inflammatory cytokine production in poly(I:C)-treated BEAS-2B cells. Poly(I:C) recruited the TLR3 adaptor molecule Toll/IL-1R domain-containing adaptor, inducing IFN (TRIF) and activated NF-κB signaling. Additionally, TLR3-induced mtROS generation suppression and siRNA-mediated TRIF downregulation attenuated mitochondrial antiviral signaling protein (MAVS) degradation. Our findings provide insights into the TLR3-TRIF signaling pathway and MAVS in viral infections, and suggest TLR3-mtROS as a therapeutic target for the treatment of airway inflammatory and viral infectious diseases.

Effects of Chlorella fusca-supplemented diet on intestinal microbiota and gene expression related to metabolism, stress, and immune response in Chelon labrosus

Microalgae are emerging as promising alternatives to traditional fishmeal and crop ingredients in aquaculture diets. In this study, we aimed to characterize the intestinal microbiota and evaluate the transcription of genes related to metabolism, stress, and the immune system in various tissues of thick-lipped grey mullet (Chelon labrosus) fed a diet containing 15 % of microalga Chlorella fusca against a microalgae-free control diet for 90 days. After this period, the fish were challenged with Aeromonas hydrophila and polyinosinic–polycytidylic acid (poly I:C) to assess their immune response during 72 h. Microbiota analysis revealed that dietary inclusion of microalgae did not produce significant differences in intestine diversity compared to the control group. The dominant genera differed between the groups, with Pseudomonas and Mycoplasma most abundant in the fish fed with C. fusca, and Brevinema, Cetobacterium, and Pseudomonas predominant in the control group. Gene expression analysis indicated significant changes in hif3α, mhcII, ferritin, and mx genes in different organs of fish fed the microalgae-supplemented diet. Gene expression in the head kidney showed variations after A. hydrophila or poly I:C challenges, and higher peak values were observed in poly I:C-injected fish. Furthermore, c3 mRNA levels were significantly up-regulated in the fish fed with C. fusca at 24 h following A. hydrophila challenge. In conclusion, the inclusion of C. fusca in the fish diet modifies the composition of microbial species in the intestine but does not seem to affect its functionality. Regarding the influence on gene expression, the microalgae-supplemented diet effectively modulates the transcription of stress and immune-related genes, which may potentially enhance the fish resistance to stress and infections.

Polyinosinic: polycytidylic acid induced inflammation enhances while lipopolysaccharide diminishes alloimmunity to platelet transfusion in mice.

Alloimmune responses against platelet antigens, which dominantly target the major histocompatibility complex (MHC), can cause adverse reactions to subsequent platelet transfusions, platelet refractoriness, or rejection of future transplants. Platelet transfusion recipients include individuals experiencing severe bacterial or viral infections, and how their underlying health modulates platelet alloimmunity is not well understood. This study investigated the effect of underlying inflammation on platelet alloimmunization by modelling viral-like inflammation with polyinosinic-polycytidylic acid (poly(I:C)) or gram-negative bacterial infection with lipopolysaccharide (LPS), hypothesizing that underlying inflammation enhances alloimmunization. Mice were pretreated with poly(I:C), LPS, or nothing, then transfused with non-leukoreduced or leukoreduced platelets. Alloantibodies and allogeneic MHC-specific B cell (allo-B cell) responses were evaluated two weeks later. Rare populations of allo-B cells were identified using MHC tetramers. Relative to platelet transfusion alone, prior exposure to poly(I:C) increased the alloantibody response to allogeneic platelet transfusion whereas prior exposure to LPS diminished responses. Prior exposure to poly(I:C) had equivalent, if not moderately diminished, allo-B cell responses relative to platelet transfusion alone and exhibited more robust allo-B cell memory development. Conversely, prior exposure to LPS resulted in diminished allo-B cell frequency, activation, antigen experience, and germinal center formation and altered memory B cell responses. In conclusion, not all inflammatory environments enhance bystander responses and prior inflammation mediated by LPS on gram-negative bacteria may in fact curtail platelet alloimmunization.

Identification, functional characterization and expression pattern of interferon-gamma (IFN-γ) and interferon-gamma receptor 1 (IFNGR1) in Nibea albiflora

Interferon-gamma (IFN-γ) is an inflammatory cytokine that plays a crucial role in regulating both innate and cell-mediated immune responses by binding to a receptor complex made up of IFNGR1 and IFNGR2. In this study, the complete cDNA of IFN-γ and IFNGR1 from Nibea albiflora were cloned and functionally characterized (named NaIFN-γ and NaIFNGR1), whose complete cDNA sequences were 1593 bp and 2792 bp, encoding 201 and 399 amino acids, respectively. Multiple sequence alignment and phylogenetic analysis showed that the concluded amino acids sequences of NaIFN-γ and NaIFNGR1 shared high identity with their teleost orthologues including the IFN-γ signature and nuclear localization signal (NLS) motif in NaIFN-γ and FN Ⅲ domain in NaIFNGR1. Real-time PCR showed that NaIFN-γ and NaIFNGR1 constitutively expressed in all tested tissues, such as the head-kidney, spleen, liver, kidney, gill, muscle, blood, and intestine with the highest expression of NaIFN-γ and NaIFNGR1 appearing in the liver and gill, respectively. After experiencing stimulation with Polyinosinic-polycytidylic acid (Poly (I:C)), Vibrio alginolyticus (V. alginolyticus) or Vibrio parahaemolyticus (V. parahaemolyticus), NaIFN-γ and NaIFNGR1 mRNA were up-regulated with the time-dependent model. Due to the presence of a nuclear localization signal (NLS), the subcellular localization revealed that NaIFN-γ dispersed throughout the cytoplasm and nucleus. NaIFNGR1, as a member of Cytokine receptor family B, was primarily expressed on the cell membrane. When NaIFN-γ and NaIFNGR1 were co-transfected, their fluorescence signals overlapped on the membrane of HEK 293T cells indicating the potential interaction between IFN-γ and IFNGR1. The GST-pull-down results further showed that NaIFN-γ could directly interact with the extracellular region of NaIFNGR1, further confirming the affinity between IFN-γ and IFNGR1. Taken together, the results firstly demonstrated that the NaIFN-γ ligand-receptor system existed in N.albiflora and played a pivotal part in N.albiflora's immune response against pathogenic bacterial infections, which contributed to the better understanding of the role of IFN-γ in the immunomodulatory mechanisms of teleost.

Paracrine Responses of Cardiosphere-Derived Cells to Cytokines and TLR Ligands: A Comparative Analysis.

Cardiosphere-derived cells (CDCs) are currently being evaluated in clinical trials as a potential therapeutic tool for regenerative medicine. The effectiveness of transplanted CDCs is largely attributed to their ability to release beneficial soluble factors to enhance therapeutic effects. An emerging area of research is the pretreatment of stem cells, including CDCs, with various cytokines to improve their therapeutic properties. This strategy aims to enhance their survival, proliferation, differentiation, and paracrine activities after transplantation. In our study, we investigated the differential effects of various cytokines and TLR ligands on the secretory phenotype of human CDCs. Using a magnetic bead-based immunoassay, we analyzed the CDCs-conditioned media for 41 cytokines and growth factors and detected the presence of 21 cytokines. We found that CDC incubation with lipopolysaccharide, a TLR4 ligand, and the cytokine combination of TNF/IFN significantly increased the secretion of most of the cytokines detected. Specifically, we observed an increased secretion and gene expression of IP10, MCP3, IL8, and VEGFA. In contrast, the TLR3 ligand polyinosinic-polycytidylic acid and TGF-beta had minimal effects on CDC cytokine secretion. Additionally, TNF/IFN, but not LPS, enhanced ICAM1 expression. Our findings offer new insights into the role of cytokines in potentially modulating the biology and regenerative potential of CDCs.

The effect of TLR3 priming conditions on MSC immunosuppressive properties

BackgroundMesenchymal stromal cells (MSCs) have regenerative and immunomodulatory properties, making them suitable for cell therapy. Toll-like receptors (TLRs) in MSCs respond to viral load by secreting immunosuppressive or proinflammatory molecules. The expression of anti-inflammatory molecules in MSCs can be altered by the concentration and duration of exposure to the TLR3 ligand polyinosinic-polycytidylic acid (poly(I:C)). This study aimed to optimize the preconditioning of MSCs with poly(I:C) to increase immunosuppressive effects and to identify MSCs with activated TLR3 (prMSCs).MethodsFlow cytometry and histochemical staining were used to analyze MSCs for immunophenotype and differentiation potential. MSCs were exposed to poly(I:C) at 1 and 10 μg/mL for 1, 3, and 24 h, followed by determination of the expression of IDO1, WARS1, PD-L1, TSG-6, and PTGES2 and PGE2 secretion. MSCs and prMSCs were cocultured with intact (J−) and activated (J+) Jurkat T cells. The proportion of proliferating and apoptotic J+ and J− cells, IL-10 secretion, and IL-2 production after cocultivation with MSCs and prMSCs were measured. Liquid chromatography–mass spectrometry and bioinformatics analysis identified proteins linked to TLR3 activation in MSCs.ResultsPoly(I:C) at 10 μg/mL during a 3-h incubation caused the highest expression of immunosuppression markers in MSCs. Activation of prMSCs caused a 18% decrease in proliferation and a one-third increase in apoptotic J+ cells compared to intact MSCs. Cocultures of prMSCs and Jurkat cells had increased IL-10 and decreased IL-2 in the conditioned medium. A proteomic study of MSCs and prMSCs identified 53 proteins with altered expression. Filtering the dataset with Gene Ontology and Reactome Pathway revealed that poly(I:C)-induced proteins activate the antiviral response. Protein‒protein interactions by String in prMSCs revealed that the antiviral response and IFN I signaling circuits were more active than in native MSCs. prMSCs expressed more cell adhesion proteins (ICAM-I and Galectin-3), PARP14, PSMB8, USP18, and GBP4, which may explain their anti-inflammatory effects on Jurkat cells.ConclusionsTLR3 activation in MSCs is dependent on exposure time and poly(I:C) concentration. The maximum expression of immunosuppressive molecules was observed with 10 µg/mL poly(I:C) for 3-h preconditioning. This priming protocol for MSCs enhances the immunosuppressive effects of prMSCs on T cells.

TLR3-Dependent Induction of TF Is Required to Maintain Lung Hemostasis during Poly IC-Induced ARDS-like Lung Dysfunction in Mice

Background: Respiratory virus infection causes damage to the epithelial-endothelial barrier of the lung. Mice challenged with influenza A virus (IAV) exhibit bleeding in the airspace. IAV increases tissue factor (TF) expression in epithelial cells (EpC) of the lung and deletion of lung EpC TF is associated with increased bleeding. aThe ssRNA viruses IAV undergo a dsRNA genomic phase during viral replication. Poly IC is a chemical mimetic of dsRNA. dsRNA acts like PAMPs and can activate the innate immune receptor, toll-like receptor 3 (TLR3). TLR3 stimulation of endothelial cells increased TF expression. However, the role of TLR3 in virus-induced TF expression in the lung TF has not been studied. Aim: To investigate the role of TLR3 in induction of TF during poly IC induced acute respiratory distress syndrome (ARDS)-like lung dysfunction in mice Methods: The murine lung EpC line, E10, was treated with the dsRNA mimetic (5 µg/mL), poly IC, for 0-6h. TF expression was measured by western blotting and a one-stage plasma clotting assay. Wild-type (WT) mice, mice with lung EpC TF deletion (TF fl/fl;SPCCre +, TFΔEpC) and their controls (TFfl/fl) as wells as TLR3 +/+ and TLR3 -/- mice were used in the study. To induce ARDS, poly IC (100 µg in 50 µL PBS) was administered intranasally daily for 3 days to adult mice (both sexes). Lung function was recorded noninvasively using the Buxco whole-body plethysmography system and plasma and bronchoalveolar lavage fluid (BALF) were collected before and 24 hours after the last administration of poly IC. Cellular composition of the BALF and blood was analyzed by an automated cell counter. Lung TF activity was quantified by one-stage plasma clotting and TF activity of extracellular vesicles (EV-TF) was analyzed by two-stage FXa generation assay. Results: Poly IC stimulation induced NFκB-dependent TF expression in E10 cells in dose and time-dependent manner. In addition, poly IC administration induced ARDS-like lung dysfunction, local lung inflammation and coagulation activation in WT mice compared to PBS-treated WT mice. Lung TF activity was increased 2-fold after poly IC administration compared to PBS-treated mice. Mice with lung EpC TF deficiency (TFΔEpC) did not exhibit an increase in lung TF or EV-TF in BALF after poly IC administration compared to controls. Importantly, TFΔEpC mice exhibited reduced activation of coagulation, impaired pulmonary hemostasis and increased hemorrhage into the airspace after poly IC compared to their littermate controls. In addition, TFΔEpC mice showed increased signs of poly IC-induced ARDS and had reduced lung function, increased lung injury and local inflammation compared to their control mice after poly IC. TLR3 -/- mice had significantly less EV-TF activity and less thrombin-antithrombin complexes (TAT) in BALF compared to TLR3 +/+ mice after poly IC. Conclusion: We show that the dsRNA mimetic poly IC induces lung EpC TF expression in vitro and vivo in part via TLR3-dependent NFκB pathway activation. TLR3 stimulation by intranasal poly IC results in sterile inflammation, and ARDS-like phenotype in mice similarly to that observed after IAV infection. Importantly, a deficiency in lung EpC TF leads to impaired lung hemostasis that is associated with an increased poly IC-induced ARDS phenotype as seen previously in our studies using IAV infection of mice. dsRNA induces induction of lung TF via TLR3. We proposed that induction of TF expression in the lung during respiratory viral infections protects against alveolar hemorrhage but can also contribute to thrombosis.

Application of State Transition Theory and Treatment Modeling for Predicting Response to Chemotherapy in a Mouse Model of Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a cancer of the myeloid line of blood cells, and the cancer originates in the bone marrow (BM) and circulates the body through the peripheral blood (PB), which can rapidly lead to BM failure and death. AML initiation and progression are composed of multiple biological properties, and we have previously shown that the state transition theory, state-space, and a model of the stochastic differential equation (SDE) could predict AML disease evolution using the mRNA of a conditional Cbfb-MYH11 (CM) knock-in mouse model. The model of the SDE represents AML evolution from health to disease as a state transition of the transcriptome state described as a particle undergoing Brownian motion in a double-well quasi-potential, where critical points define states of healthy state, c1, transition to AML, c2, and overt AML, c3. Along with the disease evolution of AML, prediction, and understanding of AML disease responses from chemotherapy aiming to provide optimized therapeutic strategies are required. Analyzing disease responses to chemotherapy from the state transition theory perspective will give us an understanding of post-chemotherapy disease dynamics and useful predictions which have the possibility to optimize treatment processes. To test the applicability of the AML state transition model, a time-series experiment using the conditional CM knock-in mouse model and state-transition modeling were performed. The mouse model was designed to recapitulate the human inv(16) AML, the leukemogenic fusion gene Cbfb-MYH11 (CM) in conditional CM knock-in mice (Cbfb56M/+/Mx1-Cre) cause the development of AML with a median survival of approximately 4 months after induction of CM. To induce CM expression, 6-8 weeks old CM knock-in mice were injected intraperitoneally with polyinosinic-polycytidylic acid [poly (I:C)] (InvivoGen, tlrl-picw-250) at 14 mg/kg/dose every other day for a total of 7 doses. CM leukemic mice were treated with a combination of cytarabine (50mg/kg/day; 5 days) and daunorubicin (1.5mg/kg/day; 3 days) after detection of overt leukemia, which is monitored by circulating leukemia blast (cKit+ > 20%) to model the 7+3 standard of care treatment for newly diagnosed AML. We used three independent experiments of mice as training and test cohorts (Group 1, Group 2, and Group 3). We collected 42 PBMC and 1 BM from CM-induced mice from Group 1 (4 AML and 1 control), 68 PBMC and 2 BM from Group 2 (4 AML), and 64 PBMC from Group 3 (3 AML and 2 control). The samples were collected weekly before, during, and following chemotherapy and subjected to RNA sequencing. The effects of chemotherapy were observed in the AML state-space with chronological time points as the transcriptome particle moving from leukemia state, c3, towards a state of healthy state, c1, crossing the unstable state, c2. The relapse was defined as the time of the first observation after the particle crosses back over unstable state, c2, towards the leukemic state, c3. The 10 AML mice out of 11 AML mice achieved a partial response with a mean time to relapse of 5 weeks. All 11 AML mice showed the anti-correlation between AML state in the state space was anti-correlated with the blast percentages (ckit%). We modified the state transition treatment model by introducing a parameter, γ, and the half-life of cytarabine (31.1 hours) and daunorubicin (21.9 hours). The gamma parameter is a force that works against the double-well quasi potential (γ >1) and represents the anti leukemogenic effects of cytarabine and daunorubicin. Gamma was determined by fitting the model to 6 AML mice data from the training cohort. The value was determined to be γ=2.7, providing a novel quantification of the treatment effect. We performed a mean arrival time analysis using simulations of the state transition treatment model, which accurately predicted the time to relapse with a prediction error of 6.6 days for the 3 AML mice from the test cohort. We could apply the state transition theory and propose the state transition treatment model to simulate the treatment process and the response from chemotherapy. Our model accurately predicted the time to respond to chemotherapy, from leukemia to health, and relapse, from health to leukemia, in the CM mouse model after chemotherapy. The state transition treatment model has implications for improving therapeutic strategies by targeting transcriptome state transition critical points in human AML.