UiO-66 nanoparticles combat influenza A virus in mice by activating the RIG-I-like receptor signaling pathway.

The Influenza A virus (IAV) is a zoonotic pathogen that infects humans and various animal species. Infection with IAV can cause fever, anorexia, and dyspnea and is often accompanied by pneumonia characterized by an excessive release of cytokines (i.e., cytokine storm). Nanodrug delivery systems and nanoparticles are a novel approach to address IAV infections. Herein, UiO-66 nanoparticles (NPs) are synthesized using a high-temperature melting reaction. The in vitro and in vivo optimal concentrations of UiO-66 NPs for antiviral activity are 200 µg mL-1 and 60 mg kg-1, respectively. Transcriptome analysis revealed that UiO-66 NPs can activate the RIG-I-like receptor signaling pathway, thereby enhancing the downstream type I interferon antiviral effect. These NPs suppress inflammation-related pathways, including the FOXO, HIF, and AMPK signaling pathways. The inhibitory effect of UiO-66 NPs on the adsorption and entry of IAV into A549 cells is significant. This study presents novel findings that demonstrate the effective inhibition of IAV adsorption and entry into cells via UiO-66 NPs and highlights their ability to activate the cellular RIG-I-like receptor signaling pathway, thereby exerting an anti-IAV effect in vitro or in mice. These results provide valuable insights into the mechanism of action of UiO-66 NPs against IAV and substantial data for advancing innovative antiviral nanomedicine.

Vital role of autophagy flux inhibition of placental trophoblast cells in pregnancy disorders induced by HEV infection.

Hepatitis E virus (HEV) has become one of the important pathogens that threaten the global public health. Type 3 and 4 HEV are zoonotic, which can spread vertically and cause placental damage. At the same time, autophagy plays an important role in the process of embryo development and pregnancy maintenance. However, the relationship between HEV and autophagy, especially in the placenta tissue, has not been clarified. We found lower litter rates in HEV-infected female mice, with significant intrauterine abortion of the embryo (24.19%). To explore the effects of HEV infection on placenta autophagy, chorionic cells (JEG-3) and mice placenta have been employed as research objects, while the expression of autophagy-related proteins (ATGs) has been detected in JEG-3 cells with different times of HEV inoculation. The results demonstrated that the expression of protein LC3 decreased and p62 accumulated, meanwhile ATGs such as ATG4B, ATG5, and ATG9A in JEG-3 cells have decreased significantly. In addition, the maturation of autophagosomes, which referred to the process of the combination of autophagosomes and lysosomes was prevented by HEV infection as well. All processes of autophagic flux, which include the initiation, development, and maturation three stages, were suppressed in JEG-3 cells after HEV infection. Similarly, the protein and gene expression of LC3 were significantly decreased in the placenta of pregnant mice with HEV infection. In summary, our results suggested that HEV inhibited autophagy in JEG-3 cells and placenta of pregnant mice, which might be the important pathogenic mechanisms of HEV infection leading to embryo abortion.

Zeolitic Imidazolate Framework-8 Triggers the Inhibition of Arginine Biosynthesis to Combat Methicillin-Resistant Staphylococcus Aureus.

The self-preservation and intelligent survival abilities of methicillin-resistant Staphylococcus aureus (MRSA) result in the ineffective treatment of many antibiotics. Nano-drug delivery systems have emerged as a new strategy to overcome MRSA infection. ZIF-8 nanoparticles (ZIF-8 NPs) exhibit good antibacterial activities, while its molecular mechanisms are largely elusive. In this study, the ZIF-8 NPs are prepared using the room temperature solution reaction method. The values of minimum inhibitory concentration of ZIF-8 NPs against Escherichia coli and MRSA isolates are 25 and 12.5 µg mL-1 , respectively. Transcriptome and metabonomic analyses reveal that ZIF-8 NPs could trigger the inhibition of arginine biosynthesis pathway and the production of ROS, which lead to dysfunctional tricarboxylic acid cycle and disruption of cell membrane integrity, eventually killing MRSA isolates. Moreover, ZIF-8 NPs show desirable treatment and repair effects on mice model of MRSA isolates wound infected-model. The results, for the first time, reveal that the inhibition of arginine biosynthesis mediates the production of ROS and energy metabolism dysfunction contributes to the antibacterial ability of ZIF-8 NPs against MRSA. This study offers a new insight into ZIF-8 NPs combating MRSA isolates.

ZnO@Polyvinyl Alcohol/Poly(lactic acid) Nanocomposite Films for the Extended Shelf Life of Pork by Efficient Antibacterial Adhesion.

The proliferation of microorganisms is an important reason for meat spoilage and deterioration. Freezing and packaging by polymer films and preservatives are commonly used to preserve meat. While the energy consumption of freezing is very big, the polymer films made by petroleum bring up heavy environmental pressure. In the present study, biodegradable antibacterial ZnO@PLA (ZP) and ZnO@PVA/PLA (ZPP) nanocomposite films used as food packaging have been synthesized by the solvent evaporation method and coating method, respectively. Compared with films without ZnO NPs, ZP and ZPP both had long-term bacteriostasis for 24 and 120 h at temperatures of 25 and 4 °C, respectively. Moreover, the antibacterial effect showed positive relevance with the increase of the ZnO NP concentration. In addition, the antibacterial effect of ZPP was better than that of ZP in the same condition. Scanning electron microscopy showed that the numbers of methicillin-resistant staphylococcus aureus (MRSA) on ZP and ZPP were significantly reduced compared to that in the blank film, and ZPP caused the morphology of MRSA to change, which means that the antibacterial mechanism of ZP and ZPP composite films might be related to antibacterial adhesion. In conclusion, ZPP films have great potential to be regarded as the candidate of food packing to extend the shelf life of pork.

Chitosan-functionalized graphene oxide as adjuvant in HEV P239 vaccine.

Searching appropriate adjuvants for vaccine is a potent method to intense the immune efficacy. In the present study, we developed a novel Hepatitis E virus (HEV) vaccine by utilizing chitosan modified nano-graphene oxide (GO-CS) as an adjuvant to support HEV antigen P239 protein (GO/CS/P239). The characterization of GO/CS/P239 was observed by atomic force microscope. The safety of GO/CS/P239 was measured by CCK-8 method, hemolysis test and acute challenge test. The anti-HEV titers and cytokines production were analyzed by double antibody sandwich ELISA. As the results showed, by contrast with a vaccine that contained only the P239 protein, GO/CS/P239 vaccine can promote immune cells to produce more IgG antibodies and cytokines, which were able to stimulate the organism to produce stronger both cellular and humoral immunity. Collectively, GO/CS/P239 particles have been demonstrated to be safe both in vitro and in vivo, and can facilitate sufficient immune response to protect organisms from virus infection, which suggested that our exploration offers a promising alternative vaccine that can control HEV infection.

PLGA-coated methylene blue nanoparticles for photoacoustic imaging and photodynamic/photothermal cascaded precisely synergistic therapy of tumor.

Photodynamic therapy (PDT) and photothermal therapy (PTT) are synergetic treatment strategies in antitumor treatment to achieve the best anticancer efficacy. Although traditional photosensitizer materials such as methylene blue (MB) have been widely studied for PDT, the photothermal effect is rarely reported. Herein, mono-component nanoparticles lactic-co-glycolic acid-coated methylene blue (MBNPs) based on methylene blue (MB) and lactic-co-glycolic acid (PLGA) were prepared by a facile solution-based emulsification method at room temperature. The resulting nanoparticles possess high photothermal conversion efficiency and excellent photodynamic effect. For the first time, the in vitro and in vivo tests indicated an enhanced antitumor efficacy for MBNPs with combined PDT and PTT. This study provides an efficient approach to fabricate nano-MB and also demonstrates the great potential of lactic-co-glycolic acid-coated MB for biomedical applications. Most importantly, the strong tumor growth inhibition by synergistic PTT and PDT demonstrates an excellent cascaded synergistic effect of MBNPs for the tumor therapy.

Preparation and Immune Effect of HEV ORF2 P206@PLGA Nanoparticles.

The hepatitis E virus (HEV) is an important pathogen that threatens global public health. One-third of the world's population lives in the epidemic area of HEV, causing 20 million infections and 70,000 deaths annually. In China, HEV transmission has changed from human-to-human transmission of HEV1 to zoonotic transmission of HEV4, causing hepatitis outbreaks throughout the country. Protecting vulnerable groups, such as practitioners related to animal husbandry and downstream consumers who are immune deficient or pregnant, from HEV infections is an urgent task. At present, the commercial human vaccine, Hecolin® (HEV 239 vaccine), is licensed for use only in China. HEV 239 vaccine is a human vaccine developed for HEV1. Although it has a cross-protective effect on HEV4, the level of immune protection is still different. To address the transformation of domestic HEV transmission modes, there is an urgent need to develop a new vaccine against zoonotic HEV4. P206@PLGA is a vaccine candidate in which nanomaterials are used to encapsulate viral capsid proteins for the immunization of livestock animals. Our experiments show that P206@PLGA has excellent biocompatibility and safety. In addition, P206@PLGA can effectively induce animals to produce a high titer of antibodies against HEV4, and thus has the potential to become a veterinary vaccine for the prevention of HEV. This approach provides a new concept for HE prevention to reduce the transmission of HEV in farms and protect susceptible populations.

Poly Lactic-co-Glycolic Acid-Coated Toluidine Blue Nanoparticles for the Antibacterial Therapy of Wounds.

Bacterial infections in wounded skin are associated with high mortality. The emergence of drug-resistant bacteria in wounded skin has been a challenge. Toluidine blue (TB) is a safe and inexpensive photosensitizer that can be activated and used in near-infrared photodynamic therapy to effectively kill methicillin-resistant Staphylococcus aureus (MRSA). However, its aggregation-induced quenching effect largely affects its clinical applications. In this study, TB nanoparticles (NPs) were synthesized using an ultrasound-assisted coating method. Their physicochemical and biological properties were studied and evaluated by scanning electron microscopy and Fourier-transform infrared spectroscopy. The TBNPs had a broad-spectrum antibacterial activity against Gram-positive bacteria (MRSA) and Gram-negative bacteria (E. coli). In addition, MTT, hemolysis, and acute toxicity tests confirmed that TBNPs had good biocompatibility. The TBNPs exhibited a high photodynamic performance under laser irradiation and efficiently killed E. coli and MRSA through generated reactive oxygen species, which destroyed the cell wall structure. The potential application of TBNPs in vivo was studied using an MRSA-infected wound model. The TBNPs could promote wound healing within 7 days, mainly by reducing the inflammation and promoting collagen deposition and granulation tissue formation. In conclusion, the TBNPs offer a promising strategy for clinical applications against multiple-drug resistance.

TB@PLGA Nanoparticles for Photodynamic/Photothermal Combined Cancer Therapy with Single Near-Infrared Irradiation.

BACKGROUND: Phototherapy has significant potential as an effective treatment for cancer. However, the application of a multifunctional nanoplatform for photodynamic therapy (PDT) and photothermal therapy (PTT) at a single excitation wavelength remains a challenge. MATERIALS AND METHODS: The double emulsion solvent evaporation method was used to prepare toluidine blue@poly lactic-co-glycolic acid (TB@PLGA) nanoparticles (NPs). The biocompatibility of TB@PLGA NPs was evaluated, and a 660 nm luminescence was used as the light source. The photothermal effect, photothermal stability, and singlet oxygen yield of NPs in an aqueous solution verified the feasibility of NPs as a PTT/PDT synergistic therapy drug. RESULTS: TB@PLGA NPs were successfully prepared and characterized. In vitro experiments demonstrated that TB@PLGA NPs can cause massive necrosis of tumor cells and induce apoptosis through a photodynamic mechanism under 660 nm laser irradiation. The TB@PLGA NPs also achieved optimal tumor inhibition effect in vivo. CONCLUSION: The TB@PLGA NPs prepared in this study were applied as a dual-mode phototherapeutic agent under single laser irradiation. Both in vitro and in vivo experiments demonstrated the good potential of PTT/PDT for tumor inhibitors.

Mitochondrial dysfunction and mitophagy pathway activation in hepatitis E virus-infected livers of Mongolian gerbils.

Recently, hepatitis E virus (HEV) has caused large outbreaks and presented a significant public health problem. Thus, the mechanism of HEV has attracted increasing research attention. Previous studies revealed that HEV infection induced hepatocyte injuries and structural and functional changes in mitochondria. These pathological changes affected the life cycle of hepatocytes. However, the precise underlying mechanism and the effector protein responsible for this process remain unclear. In the present study, mitochondrial function and the expression of mitophagy-associated mRNA transcripts and proteins were detected in an HEV- infected Mongolian gerbil model. Observation of ultrastructural changes in the liver of the inoculated group revealed the disappearance of mitochondrial cristae of mitochondrion, blurring of the bilayer structure and cavitation in the cytoplasm. The results showed that the mitochondrial transmembrane potential of decreased, mitochondrial transition pore (MPTP) opening increased, reactive oxygen species (ROS) production increased, and glutathione peroxidase (GSH-Px) activity decreased in the HEV-inoculated group. Moreover, the LC3, Beclin1, BNIP3L, Parkin, PINK1 and P62 mRNA levels were significantly increased (p < 0.05 and p < 0.01) in the inoculated group. Western blot and immunohistochemistry assay analyses detected the upregulation of the mitophagy-associated proteins LC3, Beclin1, BNIP3L, Parkin, PINK1 and P62 (p < 0.05 and p < 0.01) in HEV-infected gerbils. All these data demonstrated that HEV infection in vivo induced mitochondrial dysfunction and the activation of the mitophagy pathway, which might be one of the key factors in hepatocyte injury.

Safety, Immunogenicity, and Effectiveness of Defective Viral Particles Arising in Mast Cells Against Influenza in Mice.

Mast cells play pivotal roles in the pathogenesis of influenza A virus (IAV) infections. Defective viral particles (DPs) often arise during IAV replication, which can interfere with the replication of infectious viruses and stimulate the antiviral response of host cells. Therefore, DPs are expected to have immune-protective functions in clinic. However, the potent immunogenicity and effectiveness of DPs arising in mast cells during IAV replication have not been reported. In the present study, we showed that DPs generated in the human mastocytoma cell line HMC-1 following H1N1 infection were safe to mice after vaccination. Compared with lung adenocarcinoma cells, A549, DPs generated in infected mast cells had much better immunostimulatory activity, enhancing both humoral and cellular immunity of hosts. Notably, they could significantly increase the expression of immune-associated cytokines, especially the IFN-γ. Due to the robust immunogenicity, thus DPs generated in infected mast cells could stimulate the robust protective immune reaction effectively to fight against lethal IAV re-challenge after vaccination, which result in the high survival, decreased lung injury as well as inhibition of viral replication and inflammatory response in lungs. This study is the first to illustrate and explore the safety, immunogenicity, and effectiveness of DPs arising in mast cells against influenza as favorable potential vaccination. The results provide insight into the advances of new prophylactic strategies to fight influenza by focusing on DPs generated in mast cells.

Two identified subsets of CD8 T cells in obstructed kidneys play different roles in inflammation and fibrosis.

Inflammation plays a crucial role in initiating renal fibrosis after injury. The infiltration of inflammatory cells, such as CD4+ T cells and macrophages, contributes to renal fibrosis following ureteric obstruction. However, the function of CD8+ T cells in obstructed kidneys remains unclear. Although CD8+ T cell depletion intensifies renal fibrosis by decreasing IFN-γ and increasing IL-4 in the kidneys, the change and role of CD8 T cell populations following environmental changes during renal fibrosis are largely unknown. Here, we identified two CD8 T cell subsets in mouse obstructed kidneys with unilateral ureteric obstruction and revealed their different functions in building an inflammatory or profibrotic environment. Following renal fibrosis, the phenotypes of infiltrated CD8 T cells were mainly Tc1 (CD44+CD25-CD62L-) at the early inflammation stage and then changed to Tc2 (CD44+CD25highCD62Llow). Tc1 and Tc2 secreted IFN-γ, contributing to the decrease in the Th2-induced over-polarization of M2 macrophages and fibrosis. Moreover, Tc2 secreted pro- and anti-inflammation factors and decreased the inflammatory responses of other cells to control inflammation and fibrosis. This work and our previous study showed that CD8 T cells could balance out inflammation by controlling its level in renal fibrosis.

Lactic-co-glycolic acid-coated methylene blue nanoparticles with enhanced antibacterial activity for efficient wound healing.

Effective wound healing has been demonstrated using lactic-co-glycolic acid (PLGA)-coated methylene blue nanoparticles (MPNPs) as a novel susceptible agent for photodynamic antibacterial therapy. Compared with methylene blue (MB) solution, MPNPs have a significantly improved antibacterial effect in vitro and in vivo. The enhanced antibacterial effect is achieved through increased singlet oxygen generation in MPNPs compared to that of MB solution, as a result of the decreased aggregation-induced quenching (ACQ) effect of the MPNPs. The mouse skin infection model experiment proved that MPNP has good antibacterial effects and promotes wound healing.

ITRAQ-based quantitative proteomics reveals the first proteome profiles of piglets infected with porcine circovirus type 3.

Porcine circovirus type 3 (PCV3) infection induces porcine dermatitis and nephropathy syndrome, reproductive failure, and multisystemic inflammatory lesions in piglets and sows. To better understand the host responses to PCV3 infection, isobaric tags for relative and absolute quantification (iTRAQ) labeling combined with LC-MS/MS analysis was used for quantitative determination of differentially regulated cellular proteins in the lungs of specific-pathogen-free piglets after 4 weeks of PCV3 infection. Totally, 3429 proteins were detected in three independent mass spectrometry analyses, of which 242 differential cellular proteins were significantly regulated, consisting of 100 upregulated proteins and 142 downregulated proteins in PCV3-infected group relative to control group. Bioinformatics analysis revealed that these higher or lower abundant proteins involved primarily metabolic processes, innate immune response, MHC-I and MHC-II components, and phagosome pathways. Ten genes encoding differentially regulated proteins were selected for investigation via real-time RT-PCR. The expression levels of six representative proteins, OAS1, Mx1, ISG15, IFIT3, SOD2, and HSP60, were further confirmed by Western blotting and immunohistochemistry. This study attempted for the first time to investigate the protein profile of PCV3-infected piglets using iTRAQ technology; our findings provide valuable information to better understand the mechanisms underlying the host responses to PCV3 infection in piglets. SIGNIFICANCE: Our study identified differentially abundant proteins related to a variety of potential signaling pathways in the lungs of PCV3-infected piglets. These findings provide valuable information to better understand the mechanisms of host responses to PCV3 infection.

Cu2ZnSnS4 nanocrystals for microwave thermal and microwave dynamic combination tumor therapy.

Cu2ZnSnS4 nanocrystals (CZTS NCs) have been demonstrated to be effective in tumor therapy as a novel susceptible agent for microwave thermal and microwave dynamic therapy. CZTS NCs intensify the heating effect of microwaves with a significant temperature increase of about 15 °C compared to the control group and showed remarkable anti-tumor performance after 5 min of microwave irradiation. For the first time, we report the microwave absorption performance and singlet oxygen production of CZTS NCs used in microwave therapy, which reveals new opportunities for novel combined mechanisms of microwave thermal and microwave dynamic tumor therapies.

Chronic heat stress negatively affects the immune functions of both spleens and intestinal mucosal system in pigs through the inhibition of apoptosis.

With the globe warming, chronic heat stress (CHS) has been considered to be a common hazard that could negatively affect pig's growth and reproduction performance. However, the effects of CHS on the immune functions of pigs were seldom reported, especially the cellular immune functions of intestinal mucosal system. In order to resolve this problem, a pig CHS model was built firstly and the effects of CHS on numbers of T cells in spleen and small intestines were observed. Exposure to a temperature of 39 °C, 4 h/d for 10d, the expression of heat stress protein 70 (HSP70) was increased dramatically. Under CHS condition, the numbers of CD3+ T cells were increased dramatically in both spleens and small intestines. Besides, the numbers of CD4+T cells and the value of CD4+/CD8+T cells in spleens were also significantly increased. The results highly revealed that CHS made the equilibrium state of immune function destroyed. Furthermore, CHS mainly promoted the expression of anti-apoptosis factor B cell lymphoma-2 (Bcl-2) and thus inhibited the apoptosis of lymphocytes in spleens and intestinal mucosa. This study demonstrates for the first time that CHS negatively affects the immune functions of both spleens and intestinal mucosal system in pigs through the inhibition of apoptosis. Our study can richer the data for study of mechanism of CHS and provide new knowledge for reference of making new strategy to control the disease induced by CHS.

Brain Infection by Hepatitis E Virus Probably via Damage of the Blood-Brain Barrier Due to Alterations of Tight Junction Proteins.

Extrahepatic injury, particularly neurologic dysfunctions such as Guillain-Barré syndrome, neurologic amyotrophy, and encephalitis/meningoencephalitis/myositis were associated with HEV infection, which was supported by both clinical and laboratory studies. Thus, it is crucial to figure out how the virus invades into the central nervous system (CNS). In this study, CNS lesions were determined in rabbits and Mongolian gerbils inoculated with genotype 4 HEV. Junctional proteins were detected in HEV infected primary human brain microvascular cells (HBMVCs). Viral encephalitis associated perivascular cuffs of lymphocytes and microglial nodules were observed in HEV infected rabbits. Both positive- and negative-strand of HEV RNA was detected in brain and spinal cord in rabbits intraperitoneally infected with HEV at 28 dpi (days postinoculation), but not in rabbits gavaged with HEV. HEV ORF2 protein was further examined in both brain and spinal cord sections of infected rabbits, with positive signals located mainly in neural cells and perivascular areas. Ultrastructural study showed thickened and reduplicated basement membranes of capillary endothelium in HEV RNA positive brain tissues. In vitro study showed loss of tight junction proteins including Claudin5, Occludin, and ZO-1 (zonula occludens-1) in HBMVCs inoculated with HEV for 48 h. These findings indicated that disruption of the blood-brain barrier (BBB) might be potential mechanisms of HEV invasion into the CNS. It provides new insights to further study HEV associated neurologic disorders and will be helpful for seeking potential therapeutics for HEV infection in the future.

Hepatitis E Virus Induces Brain Injury Probably Associated With Mitochondrial Apoptosis.

Hepatitis E virus (HEV) infection has been associated with extrahepatic manifestations, particularly neurological disorders. Although it has been reported that HEV infection induced hepatocyte apoptosis associated with mitochondria injury, activation of mitochondrial apoptotic pathway in the central nervous system during HEV infection was not clearly understood. In this study, the induction of mitochondrial apoptosis-associated proteins and pro-inflammatory cytokines were detected in HEV infected Mongolian gerbil model and primary human brain microvascular endothelial cells (HBMVECs). Mitochondrial exhibited fragments with loss of cristae and matrix in HEV infected brain tissue by transmission electron microscope (TEM). In vitro studies showed that expression of NADPH oxidase 4 (NOX4) was significantly increased in HEV infected HBMVECs (p < 0.05), while ATP5A1 was significantly decreased (p < 0.01). Expressions of pro-apoptotic proteins were further evaluated. Bax was significantly increased in both HEV infected brain tissues and HBMVECs (p < 0.01). In vivo studies showed that caspase-9 and caspase-3 were activated after HEV inoculation (p < 0.01), associated with PCNA overexpression as response to apoptosis. Cytokines were measured to evaluate tissue inflammatory levels. Results showed that the release of TNFα and IL-1ß were significantly increased after HEV infection (p < 0.01), which might be attributed to microglia activation characterized by high level of IBA1 expression (p < 0.01). Taken together, these data support that HEV infection induces high levels of pro-inflammatory cytokines, associated with mitochondria-mediated apoptosis. The results provide new insight into mechanisms of extra-hepatic injury of HEV infection, especially in the central nervous system.

Induction of Porcine Dermatitis and Nephropathy Syndrome in Piglets by Infection with Porcine Circovirus Type 3.

Porcine circovirus type 3 (PCV3) is an emerging porcine circovirus that has been associated with porcine dermatitis and nephropathy syndrome (PDNS)-like clinical signs, reproductive failure, cardiac pathologies, and multisystemic inflammation in piglets and sows. Many aspects of PCV3 infection biology and pathogenesis, however, remain unknown. Here, we used a PCV3 virus stock from the rescue of an infectious PCV3 DNA clone to intranasally inoculate 4- and 8-week-old specific-pathogen-free piglets for evaluation of PCV3 pathogenesis. For 4-week-old piglets, typical clinical signs resembling those of PDNS-like disease were observed when piglets were inoculated with PCV3 alone or PCV3 combined with immunostimulation by keyhole limpet hemocyanin, with a mortality of 40% (2/5) for both types of inoculated piglets during a 28-day observation period postinoculation. Both types of inoculated piglets showed similar progressive increases in viral loads in the sera and had seroconverted to PCV3 capsid antibody after inoculation. Pathological lesions and PCV3-specific antigen were detected in various tissues and organs, including the lung, heart, kidney, lymph nodes, spleen, liver, and small intestine, in both types of inoculated piglets. The levels of proinflammatory cytokines and chemokines, including interleukin 1 beta (IL-1ß), IL-6, IL-23α, gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), and chemokine ligand 5 (CCL5), were significantly upregulated in both groups of inoculated piglets. Eight-week-old piglets also exhibited a similar PDNS-like disease but without death after PCV3 inoculation, as evidenced by pathological lesions and PCV3 antigen in various tissues and organs. These results show for the first time successful reproduction of PDNS-like disease by PCV3 infection and further provide significant information regarding the pathogenesis of PCV3 in piglets.IMPORTANCE Porcine circovirus type 3 (PCV3), an emerging porcine circovirus, is considered the cause of porcine dermatitis and nephropathy syndrome (PDNS)-like clinical signs and other systemic diseases in piglets and sows. To evaluate the pathogenesis of PCV3 infection in vivo, we used a PCV3 virus stock from the rescue of an infectious PCV3 DNA clone to intranasally inoculate 4- and 8-week-old specific-pathogen-free piglets and demonstrated successful reproduction of PDNS-like disease in animals that were inoculated with PCV3 alone or PCV3 combined with immunostimulation by keyhole limpet hemocyanin. Both 4- and 8-week-old PCV3-inoculated piglets showed similar increases in viral loads in the sera and had seroconverted to PCV3 capsid antibody. Pathological lesions and PCV3-specific antigen were detected in various tissues and organs, while numerous proinflammatory cytokines and chemokines in the sera were significantly upregulated after PCV3 inoculation. These results will provide significant information regarding the pathogenesis of PCV3 in piglets.

Metabolic profiling study on potential toxicity in male mice treated with Dechlorane 602 using UHPLC-ESI-IT-TOF-MS.

Dechlorane 602 (Dec 602), a chlorinated flame retardant, has been widely detected in different environmental matrices and biota. However, toxicity data for Dec 602 seldom have been reported. A metabolomics study based on ultra-high performance liquid chromatography coupled with ion trap time-of-flight mass spectrometry was employed to study the urine and sera metabolic profiles of mice administered with Dec 602 (0, 0.001, 0.1, and 10 mg/kg body weight per day) for 7 days. A significant difference in metabolic profiling was observed between the Dec 602 treated group and the control group by multivariate analysis, which directly reflected the metabolic perturbations caused by Dec 602. The metabolomics analyses of urine from Dec 602-exposed animals exhibited an increase in the levels of thymidine and tryptophan as well as a decrease in the levels of tyrosine, 12,13-dihydroxy-9Z-octadecenoic acid, 2-hydroxyhexadecanoic acid and cuminaldehyde. The metabolomics analyses of sera showed a decrease in the levels of kynurenic acid, daidzein, adenosine, xanthurenic acid and hypoxanthine from Dec 602-exposed animals. These findings indicated Dec 602 induced disturbance in phenylalanine, tyrosine and tryptophan biosynthesis, tryptophan metabolism, tyrosine metabolism, pyrimidine metabolism, purine metabolism, ubiquinone and other terpenoid-quinone biosynthesis; phenylalanine metabolism and aminoacyl-tRNA biosynthesis. Significant alterations of immune and neurotransmitter-related metabolites (tyrosine, tryptophan, kynurenic acid, and xanthurenic acid) suggest that the toxic effects of Dec 602 may contribute to its interactions with the immune and neuronal systems. This study demonstrated that the UHPLC-ESI-IT-TOF-MS-based metabolomic approach can obtain more specific insights into the potential toxic effects of Dec 602 at molecular level.