Difference in Intraspecies Transmissibility of Severe Fever with Thrombocytopenia Syndrome Virus Depending on Abrogating Type 1 Interferon Signaling in Mice.

Severe fever with thrombocytopenia syndrome (SFTS), a tick-borne zoonotic disease, is caused by infection with SFTS virus (SFTSV). A previous study reported that human-to-human direct transmission of SFTSV can occur. However, potential animal-to-animal transmission of SFTSV without ticks has not been fully clarified. Thus, the objective of this study was to investigate potential mice-to-mice transmission of SFTSV by co-housing three groups of mice [i.e., wild-type mice (WT), mice injected with an anti-type I interferon-α receptor-blocking antibody (IFNAR Ab), and mice with knockout of type I interferon-α receptor (IFNAR KO)] as spreaders or recipients with different immune competence. As a result, co-housed IFNAR Ab and IFNAR KO mice showed body weight loss with SFTS viral antigens detected in their sera, extracorporeal secretions, and various organs. Based on histopathology, white pulp atrophy in the spleen was observed in all co-housed mice except WT mice. These results obviously show that IFNAR Ab and IFNAR KO mice, as spreaders, exhibited higher transmissibility to co-housed mice than WT mice. Moreover, IFNAR KO mice, as recipients, were more susceptible to SFTSV infection than WT mice. These findings suggest that type I interferon signaling is a pivotal factor in mice intraspecies transmissibility of SFTSV in the absence of vectors such as ticks.

Toll-like receptor-7 signaling in Kupffer cells exacerbates concanavalin A-induced liver injury in mice.

Concanavalin A (ConA) is a plant lectin that can induce immune-mediated liver damage. ConA induced liver damage animal model is a widely accepted model that can mimic clinical acute hepatitis and immune-mediated liver injury in humans. Toll-like receptor-7 (TLR7), a member of the TLR family, plays a key role in pathogen recognition and innate immune activation. The aim of this study was to examine the role of TLR7 in the pathogenesis of ConA-induced liver injury. Acute liver injury was induced by intravenous injection with ConA in WT (wild-type) and TLR7 knockout (KO) mice. Results showed that attenuated liver injury in TLR7-deficient mice, as indicated by increased survival rate, decreased aminotransferase levels, and reduced pathological lesions, was associated with decreased release of pro-inflammatory cytokines in livers. Consistently, significantly decreased proliferation of CD4+ T cell was detected in ConA-stimulated TLR7-deficient splenocytes, but not in CD3/CD28 stimulated TLR7-deficient CD4+ T cells. Moreover, TLR7 deficiency in KCs specifically suppressed the expression of TNF-α (tumor necrosis factor-α). Depletion of KCs abolished the detrimental role of TLR7 in ConA-induced liver injury. Taken together, these results demonstrate that TLR7 can regulate the expression of TNF-α in KCs, which is necessary for the full progression of ConA-induced liver injury.

Effects of maternal cigarette smoke exposure on the progression of nonalcoholic steatohepatitis in offspring mice.

Cigarette smoke (CS) is a dominant carcinogenic agent in a variety of human cancers. CS exposure during pregnancy can adversely affect the fetus. Non-alcoholic fatty liver disease (NAFLD) is considered as a hepatic manifestation of a metabolic disorder, and ranges from simple steatosis to cirrhosis leading to hepatocellular carcinoma. Non-alcoholic steatohepatitis (NASH) is a more severe phase of NAFLD. Recently, there is increasing apprehension about the CS-related chronic liver diseases. Therefore, we examined whether maternal CS exposure could affect the pathogenesis of NASH in offspring. Mainstream CS (MSCS) was exposed to pregnant C57BL/6 mice via nose-only inhalation for 2 h/day, 5 days/week for 2 weeks from day 6 to 17 of gestation at 0, 300, or 600 µg/L. Three-week-old male offspring mice were fed methionine and choline-supplemented (MCS) diet or methionine and choline-deficient including high-fat (MCDHF) diet for 6 weeks to induce NASH. Maternal MSCS exposure increased the severity of NASH by increasing serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, hepatic total cholesterol (TC) and triglyceride (TG) levels, pro-inflammation, fibrosis, and steatosis in offspring mice. Especially, maternal MSCS exposure significantly downregulated the phosphorylation of AMP-activated protein kinase (AMPK) in MCDHF diet-fed offspring mice. Subsequently, the protein levels of sterol regulatory element-binding protein (SREBP)-1c and stearoyl-CoA desaturase-1 (SCD1) were upregulated by maternal MSCS exposure. In conclusion, maternal MSCS exposure exacerbates the progression of NASH by modulating lipogenesis on offspring mice. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-022-00153-1.

Oral administration of Jinan Red Ginseng and licorice extract mixtures ameliorates nonalcoholic steatohepatitis by modulating lipogenesis.

BACKGROUND: Nonalcoholic steatohepatitis (NASH) is one of the main chronic liver diseases. NASH is identified by lipid accumulation, inflammation, and fibrosis. Jinan Red Ginseng (JRG) and licorice have been widely used because of their anti-inflammatory and hepatoprotective effects. Hence, this study assessed JRG and licorice extract mixtures' effects on NASH progression. METHODS: Palmitic acid (PA) and the western diet (WD) plus, high glucose-fructose water were used to induce in vitro and in vivo NASH. Mice were orally administered with JRG-single (JRG-S) and JRG-mixtures (JRG-M; JRG-S + licorice) at 0, 50, 100, 200 or 400 mg/kg/day once a day during the last half-period of diet feeding. RESULTS: JRG-S and JRG-M reduced NASH-related pathologies in WD-fed mice. JRG-S and JRG-M consistently decreased the mRNA level of genes related with inflammation, fibrosis, and lipid metabolism. The treatment of JRG-S and JRG-M also diminished the SREBP-1c protein levels and the p-AMPK/AMPK ratio. The FAS protein levels were decreased by JRG-M treatment both in vivo and in vitro but not JRG-S. CONCLUSION: JRG-M effectively reduced lipogenesis by modulating AMPK downstream signaling. Our findings suggest that this mixture can be used as a prophylactic or therapeutic alternative for the remedy of NASH.

Attraction and Repellent Behaviors of Culicoides Biting Midges toward Cow Dung, Carbon Dioxide, and Essential Oils.

Culicoides biting midges (Diptera: Ceratopogonidae) are hematophagous arthropod vectors that transmit epizootic arthropod-borne viruses (arboviruses). Arboviruses are recognized as causes of pregnancy loss, encephalomyelitis, and congenital malformations in ruminants. Therefore, continuous monitoring and control of Culicoides, which causes significant damage to industrial animals are necessary. We performed attraction and repellent tests in Culicoides using various essential oils, cow dung, and carbon dioxide (CO2). Culicoides tended to move more to cow dung (60.8%, P<0.0001) and CO2 (63.8%, P<0.01). To the essential oils as repellents, 26.1% (P<0.0001), 18.7% (P<0.001), and 25.5% (P<0.01) of the Culicoides moved to the lavender, lemongrass, and eucalyptus chamber, respectively. The Culicoides that moved to the 3 essential oils chambers showed markedly low activity. Collectively, it was showed that Culicoides tended to be attractive to cow dung and CO2, and repellent from the 3 essential oils.

Ultra- and micro-structural changes of respiratory tracts in SARS-CoV-2 infected Syrian hamsters.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is causing a global crisis. It is still unresolved. Although many therapies and vaccines are being studied, they are still in their infancy. As this pandemic continues, rapid and accurate research for the development of therapies and vaccines is needed. Therefore, it is necessary to understand characteristics of diseases caused by SARS-CoV-2 through animal models. Syrian hamsters are known to be susceptible to SARS-CoV-2. They were intranasally inoculated with SARS-CoV-2. At 2, 4, 8, 12, and 16 days post-infection (dpi), these hamsters were euthanized, and tissues were collected for ultrastructural and microstructural examinations. Microscopic lesions were prominent in the upper and lower respiratory tracts from 2 and 4 dpi groups, respectively. The respiratory epithelium in the trachea, bronchiole, and alveolar showed pathological changes. Inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils were infiltrated in/around tracheal lamina propria, pulmonary vessels, alveoli, and bronchiole. In pulmonary lesions, alveolar wall was thickened with infiltrated inflammatory cells, mainly neutrophils and macrophages. In the trachea, epithelial damages started from 2 dpi and recovered from 8 dpi, consistent with microscopic results, High levels of SARS-CoV-2 nucleoprotein were detected at 2 dpi and 4 dpi. In the lung, lesions were most severe at 8 dpi. Meanwhile, high levels of SARS-CoV-2 were detected at 4 dpi. Electron microscopic examinations revealed cellular changes in the trachea epithelium and alveolar epithelium such as vacuolation, sparse micro-organelle, and poor cellular margin. In the trachea epithelium, the number of cytoplasmic organelles was diminished, and small vesicles were prominent from 2 dpi. Some of these electron-lucent vesicles were filled with virion particles. From 8 dpi, the trachea epithelium started to recover. Because of shrunken nucleus and swollen cytoplasm, the N/C ratio of type 2 pneumocyte decreased at 8 and 12 dpi. From 8 dpi, lamellar bodies on type 2 pneumocyte cytoplasm were increasingly observed. Their number then decreased from 16 dpi. However, there was no significant change in type 1 pneumocyte. Viral vesicles were only observed in the cytoplasm of type 2 pneumocyte. In conclusion, ultra- and micro-structural changes presented in this study may provide useful information for SARS-CoV-2 studies in various fields.

Ethanol Extract of Orostachys japonicus A. Berger (Crassulaceae) Protects Against Type 2 Diabetes by Reducing Insulin Resistance and Hepatic Inflammation in Mice.

Type 2 diabetes (T2D) is a threaten human health problem, and accompanied by hyperglycemia and disorder of insulin secretion, is a major cause of abnormalities in maintaining blood glucose homeostasis. Also, low-grade inflammation, as well as insulin resistance (IR), is a common feature in patients with T2D. Numerous causes of the outbreak of T2D have been suggested by researchers, who indicate that genetic background and epigenetic predisposition, such as overnutrition and deficient physical activity, hasten the promotion of T2D milieu. Orostachys japonicus A. Berger (O. japonicus) is a herbal and remedial plant whose various activities include hemostatic, antidotal, febrile, and anti-inflammatory. Hence, we designed to evaluate the antidiabetic efficacy of ethanol extracts of O. japonicus (OJE). Six-week-old C57BL/Ksj-db/db (db/db) mice were used. The results showed that mice given various concentrations of OJE (0, 50, 100, and 200 mg/kg per day) for 8 weeks showed significantly reduced hyperglycemia, IR, and liver injury, confirmed by measuring diabetic parameters, serum, and hepatic biochemicals. Furthermore, the treatment of OJE markedly decreased the mRNA levels of proinflammatory cytokines, lipid accumulation, and gluconeogenesis-related genes. Consistently, western blot analysis indicated that mice treated with OJE showed increased levels of phospho-c-Jun N-terminal kinase, phospho-Akt, glucose transporters 2 and 4 (GLUT2 and GLUT4) in T2D mice. Likewise, much the same results were obtained in in vitro experiments. Taken together, OJE had hopeful advantage in sustaining the glucose homeostasis and diminishing IR, and could be a safe alternative remedy for treating T2D.

Exogenous activation of toll-like receptor 5 signaling mitigates acetaminophen-induced hepatotoxicity in mice.

Acetaminophen (APAP) poisoning is the most common cause of drug-induced acute liver injury (ALI). Our results showed that toll-like receptor 5 (TLR5) was abundantly expressed in hepatocytes and dramatically downregulated in the toxic mouse livers. Hence, we herein investigated the role of TLR5 signaling after APAP overdose. Mice were intraperitoneally (i.p.) injected with APAP to induce ALI, and then injected with flagellin at one hour after APAP administration. Flagellin attenuated APAP-induced ALI based on decreased histopathologic lesions, serum biochemical, oxidative stress, and inflammation. Furthermore, the protective effects of flagellin were abolished by TH1020 (a TLR5 antagonist) treatment. These results suggest that flagellin exerted protective effects on ALI via TLR5 activation. Mechanistically, flagellin injection promoted the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus in hepatocytes. Consistent with the in vivo results, flagellin increased the activation of Nrf2 in hepatocytes, resulting in decreased APAP toxicity. ML385, a selective inhibitor of Nrf2, abolished the flagellin-mediated hepatoprotective effects in damaged livers and hepatocytes. Additionally, the flagellin-induced Nrf2 translocation was dependent upon the activation of TLR5-JNK/p38 pathways. These findings suggest that TLR5 signaling-induced Nrf2 activation, at least partially, contributed to the protection against APAP-induced ALI by flagellin treatment.

Orostachys japonicus A. Berger (Crassulaceae) Exerts Antidiabetic Activity by Improving Glucose and Lipid Levels in Type 2 Diabetic Mice.

Orostachys japonicus A. Berger and Momordica charantia Linn have been widely used as an alternative medicine. Recently, patients with type 2 diabetes (T2D) have paid increasing attention to medical nutrition therapy due to its safety and cost-effectiveness. Therefore, we have developed a new health functional food that consists of a mixed extract of O. japonicus and M. charantia. The aim of this study is designed to assess the antidiabetic efficacy of O. japonicus and M. charantia extracts (OME, in an 8:2 ratio), especially focusing on the effects of O. japonicus via in vivo and in vitro experiments. Seven-week-old C57BL/Ksj-db/db (db/db; a genetic animal model of T2D) mice were used for inducing diabetes. Mice were administered with various concentrations of OME (OME 0, 100, 200, or 400 mg/kg/day) for 6 weeks. Metabolic parameters, fasting blood glucose and glycosylated hemoglobin levels were measured. Histopathologic analysis and the levels of serum or hepatic biochemicals were assessed to evaluate diabetic liver injury and steatosis. The expression levels of lipogenic and gluconeogenic genes were determined by quantitative real-time polymerase chain reaction. Activation of Akt was assessed by western blot analysis. Administration of OME significantly improved metabolic parameters in db/db mice, and also reduced diabetic liver injury and steatosis were observed by OME administration in db/db mice as confirmed by histopathologic and serum or hepatic biochemical analysis. Consistently, treatment of OME significantly increased Akt activation resulting in decreased expression levels of lipid-accumulation or gluconeogenesis-related genes. Similar results were observed in in vitro experiments using single extract of O. japonicus and using OME. OME has antidiabetic effects with increased insulin sensitivity, and may be a safe alternative therapy for the management of T2D.

Dietary zerumbone, a sesquiterpene, ameliorates hepatotoxin-mediated acute and chronic liver injury in mice.

Acute liver injury (ALI) is a life-threatening clinical syndrome. Long-lasting liver injury can lead to chronic hepatic inflammation and fibrogenic responses. Zerumbone (ZER), the main constituent of rhizomes of Zingiber zerumbet Smith, has a variety of functions including anticancer activity. We investigated the role of ZER on the progression of hepatotoxin-induced liver injury. Single or repeated injection of CCl4 was used to induce acute or chronic liver injury, respectively. Mice were orally administered with ZER (10, 50 mg/kg) during the experimental period. Histopathologic analysis and serum biochemical levels revealed that ZER had hepatoprotective activities against ALI. Similar effects of ZER on injured livers were confirmed by analyses of inflammation and apoptosis-related genes. Western blot analysis showed that protein levels of apoptotic molecules were decreased, whereas antiapoptotic protein levels were conversely increased in injured livers treated with ZER. Furthermore, chronic liver injury and its associated fibrogenesis in mice were reduced by ZER treatment. These findings from our in vivo experiments further indicate that ZER could alleviate hepatocellular toxicity and inhibit activation of primary hepatic stellate cells. Our results suggest that ZER might have potential as a safe and prophylactic alternative to prevent acute and chronic liver injury.

Analysis of Five Arboviruses and Culicoides Distribution on Cattle Farms in Jeollabuk-do, Korea.

Arthropod-borne viruses (Arboviruses) are transmitted by arthropods such as Culicoides biting midges and cause abortion, stillbirth, and congenital malformation in ruminants, apparently leading to economic losses to farmers. To monitor the distribution of Culicoides and to determine their relationship with different environmental conditions (temperature, humidity, wind speed, and altitude of the farms) on 5 cattle farms, Culicoides were collected during summer season (May-September) in 2016 and 2017, and analyzed for identification of species and detection of arboviruses. About 35% of the Culicoides were collected in July and the collection rate increased with increase in temperature and humidity. The higher altitude where the farms were located, the more Culicoides were collected on inside than outside. In antigen test of Culicoides against 5 arboviruses, only Chuzan virus (CHUV) (2.63%) was detected in 2016. The Akabane virus (AKAV), CHUV, Ibaraki virus and Bovine ephemeral fever virus (BEFV) had a positive rate of less than 1.8% in 2017. In antigen test of bovine whole blood, AKAV (12.96%) and BEFV (0.96%) were positive in only one of the farms. As a result of serum neutralization test, antibodies against AKAV were generally measured in all the farms. These results suggest that vaccination before the season in which the Culicoides are active is probably best to prevent arbovirus infections.