Polyinosinic-polycytidylic Acid Research Articles

Nile tilapia TRIM39 recruits I3K413 and I3KL45 as adaptors and is involved in the NF‐κB pathway

Tripartite motif (TRIM) proteins play a regulatory function in cancer, cell apoptosis and innate immunity. To understand the role of TRIM39 in Nile tilapia (Oreochromis niloticus), TRIM39 cDNA was isolated. The total length of TRIM39 cDNA was 5025 bp. The deduced OnTRIM39 protein contains 549 amino acids and has conserved domains of the TRIM family, which are the RING, B-box, coiled-coil and PRY-SPRY domains. OnTRIM39 mRNA was widely expressed in various tissues. After challenge with Streptococcus agalactiae and stimulation with polyinosinic polycytidylic acid [poly (I:C)] and lipopolysaccharides (LPS), the amount of OnTRIM39 transcript was changed in various tested tissues. OnTRIM39 overexpression increased NF-κB activity. OnTRIM39 was present in the cytoplasm. Mass spectrometry of proteins pulled down with recombinant OnTRIM39 showed that 250 proteins potentially interact with OnTRIM39. The authors selected I3K4I3 from the 250 candidate proteins to verify its interaction with TRIM39. They also selected I3KL45, a member of the same 14-3-3 protein family, to verify its interaction with TRIM39. The results of pull-down assays showed that OnTRIM39 interacted with both I3K413 and I3KL45. These results contribute to further study of the innate immune mechanism of tilapia.

Intranasal bovine β-defensin-5 enhances antituberculosis immunity in a mouse model by a novel protein-based respiratory mucosal vaccine

ABSTRACT Respiratory mucosal immunization is an effective immunization strategy against tuberculosis (TB), and effective mucosal vaccines require adjuvants that can promote protective immunity without deleterious inflammation. Mucosal BCG (Bacille Calmette-Guerin) is effective, but it causes a severe inflammatory response in the lung. A novel less cytotoxic mucosal vaccine AH-PB containing Mycobacterium tuberculosis (Mtb) cell surface antigens Ag85A and HspX (AH), as well as polyinosinic-polycytidylic acid (Poly IC) and bovine neutrophil β-defensin-5 (B5) adjuvants were prepared, with the overarching goal of protecting against TB. Then, the immunogenicity and protective efficacy of these vaccines via the intranasal route were evaluated in a mouse model. Results showed that intranasal AH-PB promoted tissue-resident memory T cells (TRMs) development in the lung, induced antigen-specific antibody response in airway, provided protection against Mycobacterium bovis (M. bovis), conferred better protection than parenteral BCG in the later stage of infection, and boosted the protective immunity generated by BCG in mice. Moreover, both B5 and Poly IC were indispensable for the protection generated by AH-PB. Furthermore, intranasal immunization with AH-B5 fusion vaccines also provided similar protection against M. bovis compared to AH-PB. Collectively, B5-based TB vaccine via the intranasal route is a promising immunization strategy against bovine TB, and this kind of immunization strategy may be applied to human TB vaccine development. These findings highlight the potential importance of B5 as a mucosal adjuvant used in TB vaccines or other respiratory disease vaccines.

A novel chemerin receptor 1 (Chemerin1) takes part in the immune response of cobia (Rachycentron canadum)

Chemerin receptor 1 (Chemerin1) plays a critical role in innate and adaptive immune systems. In this study, a cobia (Rachycentron canadum) Chemerin1 was identified, and its molecular characterization and expression patterns were analyzed. Multiple sequence alignment revealed that the RcChemerin1 possessed a typical dynein regulatory complex (DRC) motif. There was also a potential N-glycosylation site in the extracellular regions of the N-terminus and intracellular loops (ICL) 1 region. Phylogenetic analysis demonstrated that the RcChemerin1 was clustered together with homologous proteins from other fish species. RcChemerin1 was constitutively expressed in a wide range of tissues (especially in immune-related tissues) with different expression levels, which suggests that the RcChemerin1 plays different roles in un-stimulated tissues. RcChemerin1 expression showed up-regulation in the head kidney after Vibrio harveyi challenge. Up-regulation in the head kidney and spleen was also observed after polyinosinic-polycytidylic acid (poly I: C) challenge, which suggests that RcChemerin1 may play vital roles during bacterial and viral infection. The differential responses of immune organs to bacteria and poly I: C imply the differences in defense mechanisms against viruses and bacteria.

Expression analysis of grass carp Foxp3 and its biologic effects on CXCL-8 transcription in non-lymphoid cells

Teleost Forkhead box protein P3 (Foxp3) expression was discovered not only in regulatory T cells (Tregs) but also in other cells. Compared to the extensive study on its roles in lymphoid cells, the expression pattern and biological roles of Foxp3 in non-lymphoid cells have not been elucidated in both mammals and fish species. In the present study, grass carp Foxp3 (gcFoxp3) mRNA expression was detected in different cell types, showing that it has a moderate expression level in peripheral blood leukocytes (PBLs), head kidney leukocytes (HKLs) and grass carp fibroblast-like kidney cells (CIK cells). Interestingly, gcFoxp3 mRNA and protein expression could be significantly stimulated by polyinosinic-polycytidylic acid (poly I:C) in CIK cells, indicating its participation in poly I:C-induced immune response in non-lymphoid cells. To further investigate the function of gcFoxp3, its overexpression plasmid was constructed and transfected into CIK cells. After 24 h of transfection, grass carp C-X-C chemokine ligand (CXCL) 8 (gcCXCL-8) mRNA expression was elevated, implying the modulatory role of gcFoxp3 in gcCXCL-8 mRNA expression. This notion was further supported by the features of gcCXCL-8 promoter which contained a putative Foxp3 binding site at −2196 to −2190 region. Poly I:C or overexpression of gcFoxp3 obviously stimulated gcCXCL-8 promoter activity and deletion of gcFoxp3 binding region on the promoter abolished this stimulation, revealing that Foxp3 is pivotal for transcription of CXCL-8 induced by poly I:C. In conclusion, our results collectively demonstrate expression pattern of teleost Foxp3, and illuminate novel immune function of fish Foxp3 in regulating chemokine transcription in non-lymphoid cells.

Gestational immune activation disrupts hypothalamic neurocircuits of maternal care behavior

Immune activation is one of the most common complications during pregnancy, predominantly evoked by viral infections. Nevertheless, how immune activation affects mother–offspring relationships postpartum remains unknown. Here, by using the polyinosinic-polycytidylic acid (Poly I:C) model of gestational infection we show that viral-like immune activation at mid-gestation persistently changes hypothalamic neurocircuit parameters in mouse dams and, consequently, is adverse to parenting behavior. Poly I:C-exposed dams favor non-pup-directed exploratory behavior at the expense of pup retrieval. These behavioral deficits are underlain by dendrite pruning and lesser immediate early gene activation in Galanin (Gal)+ neurons with dam-specific transcriptional signatures that reside in the medial preoptic area (mPOA). Reduced activation of an exclusively inhibitory contingent of these distal-projecting Gal+ neurons allows for increased feed-forward inhibition onto putative dopaminergic neurons in the ventral tegmental area (VTA) in Poly I:C-exposed dams. Notably, destabilized VTA output specifically accompanies post-pup retrieval epochs. We suggest that gestational immunogenic insults bias both threat processing and reward perception, manifesting as disfavored infant caregiving.

Elucidation of the inhibitory effect of (+)-hopeaphenol on polyinosinic–polycytidylic acid-induced innate immunity activation in human cerebral microvascular endothelial cells

Drug development for regulating the innate immune system is important for the prevention and treatment of autoinflammatory and autoimmune diseases. In this context, we investigated the effect of resveratrol derivatives on the inflammatory reactions in the brain. Resveratrol, which can be found in Vitis plants in the form of oligomers, exhibits neuroprotective effects; however, its regulatory effects on innate immunity are still unclear. We examined the effects of (+)-hopeaphenol, a resveratrol tetramer, and its derivatives on the polyinosinic–polycytidylic acid (poly IC)-induced production of interferon (IFN)-β and C-X-C motif chemokine 10 (CXCL10) in the cultured human cerebral microvascular endothelial cell line hCMEC/D3. (+)-Hopeaphenol (1–10 μM) inhibited the poly IC-induced production of not only CXCL10 but also retinoic acid-inducible gene-I in a dose-dependent manner and significantly reduced the poly IC-induced IFN-β gene expression and protein release from hCMEC/D3 cells by inhibiting the phosphorylation of p65 but not that of the interferon regulatory transcription factor IRF3. A docking study indicated a high affinity of (+)-hopeaphenol for p65. These results suggest that (+)-hopeaphenol can regulate the innate immune system by inhibiting the poly IC/IFN-β/CXCL10 signaling axis via suppression of the phosphorylation of the transcription factor NF-ĸB.

Pre‐ and post‐conditioning with poly I:C exerts neuroprotective effect against cerebral ischemia injury in animal models: A systematic review and meta‐analysis

BackgroundToll‐like receptor (TLR) agonist polyinosinic–polycytidylic acid (poly I:C) exerts neuroprotective effects against cerebral ischemia (CI), but concrete evidence supporting its exact mechanism of action is unclear.MethodsWe evaluated the neuroprotective role of poly I:C by assessing CI indicators such as brain infarct volume (BIV), neurological deficit score (N.S.), and signaling pathway proteins. Moreover, we performed a narrative review to illustrate the mechanism of action of TLRs and their role in CI. Our search identified 164 articles and 10 met the inclusion criterion.ResultsPoly I:C reduces BIV and N.S. (p = 0.00 and p = 0.03). Interestingly, both pre‐ and post‐conditioning decrease BIV (preC p = 0.04 and postC p = 0.00) and N.S. (preC p = 0.03 and postC p = 0.00). Furthermore, poly I:C upregulates TLR3 [SMD = 0.64; CIs (0.56, 0.72); p = 0.00], downregulates nuclear factor‐κB (NF‐κB) [SMD = −1.78; CIs (−2.67, −0.88); p = 0.0)], and tumor necrosis factor alpha (TNF‐α) [SMD = −16.83; CIs (−22.63, −11.02); p = 0.00].ConclusionWe showed that poly I:C is neuroprotective and acts via the TLR3/NF‐κB/TNF‐α pathway. Our review indicated that suppressing TLR 2/4 may illicit neuroprotection against CI. Further research on simultaneous activation of TLR3 with poly I:C and suppression of TLR 2/4 might open new vistas for the development of therapeutics against CI.

Perturbations of Marrow Stromal Cell function during Acute Inflammation

Abstract Mesenchymal stromal cells (MSCs) reside in a complex network of blood cells and can differentiate into chondrocytes, osteoblasts, and adipocytes. MSCs differentiation process is tightly regulated through intrinsic and extrinsic signals within the marrow microenvironment, leading to transcriptional programming of balanced lineage output. Inflammatory insults to this system can occur through the upregulation of activating cytokines. Pro-inflammatory cytokines’ impact on the hematopoietic lineage is well-defined, but similar impacts to stromal cells was largely undefined. To delineate these changes, we studied two well-characterized forms of inflammation: polyinosinic-polycytidylic acid (Poly(I:C)), that activates IFNα, and Lipopolysaccharide (LPS), that promotes IFNγ. Prior studies of inflammatory conditions showed bone loss; therefore, we hypothesized that there would be an increase in the MSC pool to compensate for loss of bone maturation. Using flow cytometry and lineage-tracing models of stroma, we characterize the non-hematopoietic cells’ changes following inflammatory perturbation. Our data show an increase in MSCs with decreases in osteoblasts and adipocytes following stimulation. Furthermore, we used reverse-phase protein and cytokine arrays to map the signaling mechanisms and activated pathways. We found an increase in the NFκB pathway with an accompanying increase IL-1β. Targeting of the IL-1 pathway did not phenotypically reverse the stromal perturbations but corrected the MSCs functionally. Understanding these alterations within the bone marrow microenvironment during inflammation will allow for therapeutic interventions to mediate hematopoietic diseases such as sepsis or leukemia. Supported by NIH R01 HL150078

The Effect of Various Stimulants on Cytokine Secretion Profiles in Freshly Isolated Peripheral Blood Mononuclear Cells (PBMC)

Abstract Cytokines play critical roles in in cancer, in regulating autoimmune diseases and in chemically induced tissue damage repair. In response to antibody treatment or as a result of corona virus disease (COVID), a cytokine storm may occur where high levels of inflammatory cytokines are produced leading to organ damage. To understand how to regulate cytokine levels, primary cell in vitro assays may assess the effects of small molecule compounds or antibodies. We evaluated OKT3, Polyinosinic-polycytidylic acid (Poly I:C), Resiquimod, CpG oligodeoxynucleotides (CpG ODN), DynaBeads with aCD3/aCD28, Phytohemagglutinin (PHA)-M and lipoplolysaccharide (LPS) on cytokine secretion from 6 normal donors. PBMCs isolated from fresh blood using a density gradient medium were plated at 1 × 105 cells per well in the presence and absence of the test compounds for 48 hours. Supernatants were assessed for interleukin 2 (IL-2), tumor necrosis factor-α (TNFα) and interferon-γ (IFNγ). The remaining cells were assessed for viability to evaluate cytotoxicity. Flow cytometric profiles of T cell subsets were determined. The data generated from the 6 normal donors varied greatly, though the effects of the stimulants followed the same trends. The Dynabeads (CD3/28) generated the highest values of IL-2, IFNγ and TNFα in all donors. OKT3 and PHA-M, Resiquimod and LPS generated lesser amounts of the cytokines whereas Poly I:C and CpG ODN did not induce these cytokines over background levels. Only PHA-M caused a decrease in cell viability. Additionally, the release of cytokines was not associated with activation of T cells. Cytokine release assays provide a robust readout with certain stimuli and may facilitate evaluation of novel test compounds for functional activity.

STING activation under pre-existing inflammatory conditions causes severe skin disease

Abstract The activation of the stimulator of interferon genes 1 (Sting1) pathway causes rapid induction of type I IFNs. Recently, different STING agonists are being proposed as therapeutics for controlling viral infections like those caused by the SARS-CoV-2. Considering that excessive STING activation leads to autoimmunity, this study was undertaken to investigate the effects of STING activation under pre-existing systemic inflammatory conditions induced by a viral infection. Female BALB/c mice were treated (Tx) with TLR3 agonist poly(IC), which was followed 24h later by subcutaneous injection of STING agonist diamidobenzimidazole (diAbZi). Only diAbZi or vehicle Tx mice were used as controls. Mice Tx with poly(IC) and diAbZi showed the highest systemic levels of type I IFNs, IL-6, and TNFα. Within 10 days, the salivary glands showed increased ILC1, monocytes, and CD8+ T cells. However, glandular function was not affected. Five days after Tx, except for the vehicle controls, all mice showed differing extents of redness, hair loss, and ulceration at the injection site. By day 10, diABZi alone Tx mice showed either normal skin or a small scar formation. In contrast, mice Tx with poly IC and diABZi, showed extensive hair loss, erythema, and ulceration. In addition, hematoxylin and eosin-stained skin sections showed extensive neutrophilic infiltration at the site of ulceration, epidermal thickening, and patchy lymphocytic infiltrate that extended into the subdermal layers. Our data demonstrate that STING activation under systemic inflammatory conditions, such as a viral infection, can lead to severe skin disease. Therefore, caution needs to be exercised in employing STING agonists as therapeutics for treating SARS-CoV-2.

Maternal immune activation accelerates puberty initiation and alters mechanical allodynia in male and female C57BL6/J mice.

The mechanisms that link maternal immune activation (MIA) with the onset of neurodevelopmental disorders remain largely unclear. Accelerated puberty is also associated with a heightened risk for psychopathology in later life, but there is a dearth of evidence on the impacts of maternal infection on pubertal timing. We examined the effects of MIA on reproductive development, mechanical allodynia, and sensorimotor gating in juvenile, adolescent, and adult male and female mice. Moreover, we investigated hypothalamic neural markers associated with the reproductive and stress axes. Finally, we tested the mitigating effects of environmental enrichment (EE), which has clinical relevancy in human rehabilitation settings. Our results show that administration of polyinosinic-polycytidylic acid (poly(I:C)) on gestational day 12.5 led to early preputial separation, vaginal openings, and age of first estrus in offspring. MIA exposure altered pain sensitivity across development and modestly altered prepulse inhibition. The downregulation of Nr3c1 and Oprk mRNA in the hypothalamus of juvenile mice suggests that MIA's effects may be mediated through disruption of hypothalamic-pituitary-adrenal axis activity. In contrast, life-long housing with EE rescued many of these MIA-induced consequences. Overall, our findings suggest that accelerated puberty may be associated with the deleterious effects of infection during pregnancy and the onset of psychopathology.

Characterization of Dosage Levels for In Ovo Administration of Innate Immune Stimulants for Prevention of Yolk Sac Infection in Chicks.

Innate immune stimulants, especially toll-like receptor (TLR) ligands and agonists, are the main players in the initiation of innate immunity and have been widely studied as alternatives to antibiotics to control infection. In the present study, we characterized the dosage levels of various innate immune stimulants, including unmethylated cytosine-phosphate-guanosine dinucleotide -containing oligodeoxynucleotides (CpG ODN), polyinosinic-polycytidylic acid (poly I:C), cyclic polyphosphazene 75B (CPZ75B), avian beta-defensin 2 (ABD2), and combinations of these reagents given in ovo. Data derived from a series of animal experiments demonstrated that the in ovo administration of 10–50 µg CpG ODN/embryo (on embryonic day 18) is an effective formulation for control of yolk sac infection (YSI) due to avian pathogenic Escherichia coli (E. coli) in young chicks. Amongst the different combinations of innate immune stimulants, the in ovo administration of CpG ODN 10 µg in combination with 15 µg of poly I:C was the most effective combination, offering 100% protection from YSI. It is expected that the introduction of these reagents to management practices at the hatchery level may serve as a potential replacement for antibiotics for the reduction of early chick mortality (ECM) due to YSI/colibacillosis.

Poly(I:C) attenuates myocardial ischemia/reperfusion injury by restoring autophagic function.

Polyinosinic-polycytidylic acid (poly(I:C)) is the agonist of Toll-like receptor 3 (TLR3), which participates in innate immune responses under the condition of myocardial ischemia/reperfusion injury (MIRI). It has been shown that poly(I:C) exhibited cardioprotective activities through the PI3K/Akt pathway, which is the main signal transduction pathway during autophagy. However, the precise mechanism by whether poly(I:C) regulates autophagy remains poorly understood. Thus, this study was designed to investigate the therapeutic effect of poly(I:C) against MIRI and the underlying pathway connection with autophagy. We demonstrated that 1.25 and 5mg/kg poly(I:C) preconditioning significantly reduced myocardial infarct size and cardiac dysfunction. Moreover, poly(I:C) significantly promoted cell survival by restoring autophagy flux and then regulating it to an adequate level Increased autophagy protein Beclin1 and LC3II together with p62degradation after additional chloroquine. In addition, mRFP-GFP-LC3 adenoviruses exhibited autophagy activity in neonatal rat cardiac myocytes (NRCMs). Mechanistically, poly(I:C) activated the PI3K/AKT/mTOR pathway to induce autophagy, which was abolished by LY294002 (PI3K antagonist), rapamycin (autophagy activator and mTOR inhibitor), or 3-methyladenine (autophagy inhibitor), suggesting either inhibition of the PI3K/Akt/mTOR pathway or autophagy activity interrupt the beneficial effect of poly(I:C) preconditioning. In conclusion, poly(I:C) promotes cardiomyocyte survival from ischemia/reperfusion injury by regulating autophagy via the PI3K/Akt/mTOR pathway.

Dental Pulp Cell Conditioning through Polyinosinic-Polycytidylic Acid Activation of Toll-like Receptor 3 for Amplification of Trophic Factors

IntroductionRegeneration of the pulp-dentin complex hinges on functionally diverse growth factors, cytokines, chemokines, signaling molecules, and other secreted factors collectively referred to as trophic factors. The delivery of exogenous factors and the induced release of endogenous dentin-bound factors by conditioning agents have been explored toward these goals. The aim of this study was to investigate a promising regeneration strategy based on the conditioning of dental pulp cells (DPCs) with polyinosinic-polycytidylic acid (poly[I:C]) for the amplification of endogenous trophic factors. MethodsDPCs were isolated from human dental pulps, propagated in culture, and treated with an optimized dose of poly(I:C). The 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide assay and metabolite analysis were conducted to monitor the cytotoxicity of poly(I:C). Enzyme-linked immunosorbent assays and quantitative polymerase chain reaction assays were performed to quantify the induction of trophic factors in response to DPC conditioning. Statistical significance was P < .05. ResultsThe analysis of 32 trophic factors involved in Wnt signaling, cell migration and chemotaxis, cell proliferation and differentiation, extracellular matrix remodeling and angiogenesis, and immunoregulation revealed that DPCs abundantly express many trophic factors including AMF, BDNF, BMP2, FGF1, FGF2, FGF5, HGF, MCP1, NGF, SDF1, TGFβ1, TIMP1, TIMP2, TIMP3, and VEGFA, many of which were further induced by DPC conditioning; induction was significant for BDNF, EGF, HGF, LIF, MCP1, SDF1, IL6, IL11, MMP9, and TIMP1. Both DPC proliferation and lactate production (P < .05) were inhibited by 8 μg/mL poly(I:C) relative to the control. ConclusionsIn vitro DPC conditioning through poly(I:C) activation of toll-like receptor 3 led to the amplification of trophic factors involved in tissue repair. The strategy offers promise for endodontic regeneration and tooth repair and warrants further investigation.

Protective effects of chicoric acid on polyinosinic-polycytidylic acid exposed chicken hepatic cell culture mimicking viral damage and inflammation

Virus induced damage triggered by excessive inflammation and free radical production is a major threat in the poultry industry, leading to low productivity even in vaccinated flocks. The purpose of the study was to induce inflammation with the viral double-stranded RNA analog polyinosinic-polycytidylic acid (poly I:C) on chicken primary hepatocyte – non-parenchymal cell co-cultures to investigate the immunomodulatory and cell protectant effects of chicoric acid (CA) in comparison to N-acetylcysteine (NAC). Poly I:C significantly elevated the activity of the cell damage marker, lactate dehydrogenase (LDH) and the concentration of inflammatory cytokines (IL-6, IL-8, IFN-α, IFN-γ and M-CSF) in the culture medium and decreased cellular metabolic activity. CA significantly reduced the elevated LDH and cytokine levels in a dose-dependent manner, moreover, the higher (100 µg/mL) concentration of CA even elevated the level of metabolic activity. In contrast, 10 µg/mL NAC treatment decreased the level of each inflammatory cytokine but did not rectify cell damage or metabolic depression. The results indicate, that CA, present in common plants of the Asteraceae family, proves to be a beneficial hepatoprotective, and along with NAC, an immunomodulatory supplement in vitro under a stimulus mimicking viral infection.

Glomerular endothelial expression of type I IFN-stimulated gene, DExD/H-Box helicase 60 via toll-like receptor 3 signaling: possible involvement in the pathogenesis of lupus nephritis

Background Sustained type I interferon (IFN) activation via Toll-like receptor (TLR) 3, 7 and 9 signaling has been reported to play a pivotal role in the development of lupus nephritis (LN). Although type I IFN activation has been shown to induce interferon-stimulated genes (ISGs) expression in systemic lupus erythematosus, the implication of ISGs expression in intrinsic glomerular cells remains largely unknown. Methods We treated cultured human glomerular endothelial cells (GECs) with polyinosinic-polycytidylic acid (poly IC), R848, and CpG (TLR3, TLR7, and TLR9 agonists, respectively) and analyzed the expression of DExD/H-Box Helicase 60 (DDX60), a representative ISG, using quantitative reverse transcription-polymerase chain reaction and western blotting. Additionally, RNA interference against IFN-β or DDX60 was performed. Furthermore, cleavage of caspase 9 and poly (ADP-ribose) polymerase (PARP), markers of cells undergoing apoptosis, was examined using western blotting. We conducted an immunofluorescence study to examine endothelial DDX60 expression in biopsy specimens from patients with LN. Results We observed that endothelial expression of DDX60 was induced by poly IC but not by R848 or CpG, and RNA interference against IFN-β inhibited poly IC-induced DDX60 expression. DDX60 knockdown induced cleavage of caspase 9 and PARP. Intense endothelial DDX60 expression was observed in biopsy specimens from patients with diffuse proliferative LN. Conclusion Glomerular endothelial DDX60 expression may prevent apoptosis, which is involved in the pathogenesis of LN. Modulating the upregulation of the regional innate immune system via TLR3 signaling may be a promising treatment target for LN.

Immune Activation in Pregnant Rats Affects Brain Glucose Consumption, Anxiety-like Behaviour and Recognition Memory in their Male Offspring

PurposePrenatal infection during pregnancy is a risk factor for schizophrenia, as well as for other developmental psychiatric disorders, such as autism and bipolar disorder. Schizophrenia patients were reported to have altered brain metabolism and neuroinflammation. However, the link between prenatal infection, altered brain inflammation and metabolism, and schizophrenia remains unclear. In this project, we aimed to evaluate whether there are changes in brain glucose consumption and microglia activation in the offspring of pregnant rats exposed to maternal immune activation (MIA), and if so, whether these changes occur before or after the initiation of schizophrenia-like behaviour.ProceduresPregnant rats were treated with the viral mimic polyinosinic-polycytidylic acid (MIA group) or saline (control group) on gestational day 15. Static PET scans of the male offspring were acquired on postnatal day (PND) 21, 60, and 90, using [11C]-PK11195 and deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) as tracers to measure TSPO expression in activated microglia and brain glucose consumption, respectively. On PND60 and PND90, anxiety-like behaviour, recognition memory, and sensorimotor gating were measured using the open field test (OFT), novel object recognition test (NOR), and prepulse inhibition test (PPI).Results[18F]-FDG PET demonstrated that MIA offspring displayed higher brain glucose consumption in the whole brain after weaning (p = 0.017), and in the frontal cortex during late adolescence (p = 0.001) and adulthood (p = 0.037) than control rats. [11C]-PK11195 PET did not reveal any changes in TSPO expression in MIA offspring. Prenatal infection induced age-related behavioural alterations. Adolescent MIA offspring displayed a more anxious state in the OFT than controls (p = 0.042). Adult MIA offspring showed recognition memory deficits in the NOR (p = 0.003). Our study did not show any PPI deficits.ConclusionsOur results suggest that prenatal immune activation changed neurodevelopment, resulting in increased brain glucose consumption, but not in microglia activation. The increased brain glucose consumption in the frontal cortex of MIA offspring remained until adulthood and was associated with increased anxiety-like behaviour during adolescence and recognition memory deficits in adulthood.

Globular C1q domain-containing protein from Pinctada fucata martensii participates in the immune defense process

The globular C1q domain-containing (C1qDC) protein can recognize a variety of ligands, such as pathogen-associated molecular patterns, and plays an important role in the innate immune response. Our previous studies showed that a novel globular C1q domain-containing protein (PmC1qDC-1) is involved in the damage repair process of pearl oyster shells. However, the function of PmC1qDC-1 in pearl oyster innate immunity remains unknown. In the present study, the high-level structural analysis showed that PmC1qDC-1 was a spherical structure composed of 10 strands and was similar to the AiC1qDC-2 of bay scallop (Argopecten irradians). In situ hybridization indicated that PmC1qDC-1 had strong fluorescence signal in gills. Furthermore, the mRNA expression of PmC1qDC-1 was highly induced at 6–48 h in gill after lipopolysaccharide, peptidoglycan and polyinosinic–polycytidylic acid stimulation. Additionally, we obtained the recombinant protein of PmC1qDC-1 (rPmC1qDC-1) and found that rPmC1qDC-1 had antibacterial activity against Gram-negative (i.e., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Escherichia coli, and Aeromonas hydrophila) and Gram-positive (i.e., Staphylococcus aureus and Bacillus subtilis) bacteria. These results indicated that PmC1qDC-1 might play an important role in the immune response against bacteria and viruses. This study provides clues for further studying the immune defense of Pinctada fucata martensii against pathogens and exploring the evolution of the classic pathway of complement system.

Comparative transcriptomic analysis of the liver and spleen in marbled rockfish (Sebastiscus marmoratus) challenged with polyriboinosinic polyribocytidylic acid (poly(I:C))

Marbled rockfish (Sebastiscus marmoratus) is a common coastal fish in China with considerable market value. The artificial culture of this species has not been widely popularized, and there have been few research on its vaccine or immune adjuvant. In this study, we performed transcriptome analysis of marbled rockfish spleen and liver tissue samples at 12 and 48 h after the polyinosinic-polycytidylic acid (poly(I:C)) challenge. Compared with the control group, 1067 and 598 differentially expressed genes (DEGs) were identified in the spleen and liver, respectively. GO, and KEGG enrichment analyses of DEGs revealed that some immune-related biological processes and pathways were significantly changed after poly(I:C) treatment, including primary immunodeficiency, the NF-kappa B signaling pathway, the Jak-STAT signaling pathway, and the PPAR signaling pathway. In conclusion, the findings of this research provide new insights into the immune response of marbled rockfish against poly(I:C) at the transcriptome level, and enrich the theoretical basis for the development of its immune adjuvant.

Characterization of snakehead (Channa argus) interleukin-21: Involvement in immune defense against two pathogenic bacteria, in leukocyte proliferation, and in activation of JAK–STAT signaling pathway

Interleukin-21 (IL-21), a crucial immune regulatory molecule, belongs to the common γ-chain family of type I cytokines, and exerts pleiotropic effects on multiple immune cell types in mammals. However, the characteristics and functions of fish IL-21 remain unclear. To further investigate the molecular mechanism of IL-21 in teleosts, we first cloned and identified the IL-21 gene (designated shIL-21) of the snakehead (Channa argus). The full-length open reading frame of shIL-21 is 438 bp in length, and encodes a predicted protein of 145 amino acid residues. A sequence analysis showed that shIL-21 has the typical structural characteristics of other IL-21 proteins, containing four α-helices and four conserved cysteine residues. In a phylogenetic analysis, shIL-21 clustered within a subgroup of IL-21 proteins from other teleost species and shared its closest evolutionary relationship with that of Lates calcarifer. The expression analysis showed that shIL-21 was ubiquitously expressed in all the healthy snakehead tissues tested, albeit at different levels. After infection with Nocardia seriolae or Aeromonas schubertii, the relative expression of shIL-21 was mainly upregulated in the head kidney and spleen in vivo. Similarly, after stimulation with the three pathogen analogues lipoteichoic acid, lipopolysaccharides, and polyinosinic–polycytidylic acid, the expression of shIL-21 was also induced in head kidney leukocytes in vitro. A recombinant shIL-21 protein was expressed and purified, and promoted the proliferation of head kidney leukocytes, induced the expression of genes encoding critical signaling molecules in the Janus kinase (JAK) and signal transducer and activator of transcription (STAT) pathway, including JAK1, JAK3, STAT1, and STAT3, and induced the expression of endogenous shIL-21 and genes encoding several key proinflammatory cytokines (tumor necrosis factor-α, interferon-γ, and IL-1β). Taken together, these preliminary findings suggest that shIL-21 is involved in the immune defense against bacterial infection, in leukocyte proliferation, and in the activation of the JAK–STAT pathway. They thus extend the functional studies of IL-21 in teleosts.