Exosome-mediated transfer of circRNA563 promoting hepatocellular carcinoma by targeting the microRNA148a-3p/metal-regulatory transcription factor-1 pathway.

BACKGROUND: Mesenchymal stem cells (MSCs) exert anti-oncogenic effects via exosomes containing non-coding RNA (ncRNA), which play important roles in tumor biology. Our preliminary study identified the interaction of the ncRNA hsa_circ_0000563 (circ563) and the circ563-associated miR-148a-3p in exosomes, as miR-148a-3p and its target metal-regulatory transcription factor-1 (MTF-1) are implicated in hepatocellular carcinoma (HCC) progression. AIM: To identify the clinical significance, functional implications, and mechanisms of circ563 in HCC. METHODS: The expression levels of miR-148a-3p and MTF-1 in exosomes derived from MSC and HCC cells were compared, and their effects on HCC cells were assessed. Using a dual-luciferase reporter assay, miR-148a-3p was identified as an associated microRNA of circ563, whose role in HCC regulation was assessed in vitro and in vivo. RESULTS: The silencing of circ563 blocked the HCC cell proliferation and invasion and induced apoptosis. Co-culturing of HCC cells with MSC-derived exosomes following circ563 overexpression promoted cell proliferation and metastasis and elicited changes in miR-148a-3p and MTF-1 expression. The tumor-promoting effects of circ563 were partially suppressed by miR-148a-3p overexpression or MTF-1 depletion. Xenograft experiments performed in nude mice confirmed that circ563-enriched exosomes facilitated tumor growth by upregulating the expression of MTF-1. In HCC tissues, circ563 expression was negatively correlated with miR-148a-3p expression but positively correlated with MTF-1 levels. CONCLUSION: MSCs may exhibit anti-HCC activity through the exosomal circ563/miR-148a-3p/MTF-1 pathway, while exosomes can transmit circ563 to promote oncogenic behavior by competitively binding to miR-148a-3p to activate MTF-1.

A novel laboratory-based nomogram for assessing infection presence risk in acute-on-chronic liver failure patients.

Accurate assessment of infection presence risk level, timely diagnosis, and effective control are critical for decreasing mortality of Acute­on­chronic liver failure (ACLF). We aimed to develop and validate a novel diagnostic model to accurately assess infection presence risk level in ACLF patients. 185 ACLF patients with/without infection were enrolled, and their demographic, physical findings, immune-inflammatory, hepatic function, metabolism, and coagulation-fibrinolysis indicators were analyzed. Regression analysis was performed to identify the independent diagnostic parameters, which were further used to establish diagnostic models with a nomogram for visual. An area under receiver operating characteristic curve (AUROC), calibration plots, clinical impact curves, decision curve analysis, and net reclassification index were used to evaluate and identify the best model. An external validating cohort was introduced to verify the diagnostic accuracy. We screened out white blood cell (WBC) count, LYM%, blood urea nitrogen (BUN), and D-dimer for assessing infection presence risk levels in ACLF patients. WBD (WBC + BUN + D-dimer) was established and proposed as a novel diagnostic model for infection presence risk levels assessment in ACLF patients with an AUROC of 0.803 (95%CI 0.723-0.883), 0.885 (95%CI 0.786-0.984) in training and external cohorts, respectively. In stratification analysis by ACLF etiology and stages, WBD achieved an AUROC of 0.791 (95%CI 0.691-0.891) and 0.873 (95%CI 0.78-0.966) in HBV-related and early-stage patients, respectively. Whereas a higher AUROC of 0.905 (95%CI 0.807-1.00) in the early-stage of HBV-related ACLF patients indicated its optimum application scope. WBD, a novel laboratory-based nomogram, can serve as a decision-making support tool for clinicians to assess infection presence risk levels in ACLF patients.

The regulatory mechanism of amino acids on milk protein and fat synthesis in mammary epithelial cells: a mini review.

Mammary epithelial cell (MEC) is the basic unit of the mammary gland that synthesizes milk components including milk protein and milk fat. MECs can sense to extracellular stimuli including nutrients such as amino acids though different sensors and signaling pathways. Here, we review recent advances in the regulatory mechanism of amino acids on milk protein and fat synthesis in MECs. We also highlight how these mechanisms reflect the amino acid requirements of MECs and discuss the current and future prospects for amino acid regulation in milk production.

Corticosteroid treatment in severe patients with SARS-CoV-2 and chronic HBV co-infection: a retrospective multicenter study.

BACKGROUND: The impact of corticosteroids on patients with severe coronavirus disease 2019 (COVID-19)/chronic hepatitis B virus (HBV) co-infection is currently unknown. We aimed to investigate the association of corticosteroids on these patients. METHODS: This retrospective multicenter study screened 5447 confirmed COVID-19 patients hospitalized between Jan 1, 2020 to Apr 18, 2020 in seven centers in China, where the prevalence of chronic HBV infection is moderate to high. Severe patients who had chronic HBV and acute SARS-cov-2 infection were potentially eligible. The diagnosis of chronic HBV infection was based on positive testing for hepatitis B surface antigen (HBsAg) or HBV DNA during hospitalization and a medical history of chronic HBV infection. Severe patients (meeting one of following criteria: respiratory rate > 30 breaths/min; severe respiratory distress; or SpO2 ≤ 93% on room air; or oxygen index < 300 mmHg) with COVID-19/HBV co-infection were identified. The bias of confounding variables on corticosteroids effects was minimized using multivariable logistic regression model and inverse probability of treatment weighting (IPTW) based on propensity score. RESULTS: The prevalence of HBV co-infection in COVID-19 patients was 4.1%. There were 105 patients with severe COVID-19/HBV co-infections (median age 62 years, 57.1% male). Fifty-five patients received corticosteroid treatment and 50 patients did not. In the multivariable analysis, corticosteroid therapy (OR, 6.32, 95% CI 1.17-34.24, P = 0.033) was identified as an independent risk factor for 28-day mortality. With IPTW analysis, corticosteroid treatment was associated with delayed SARS-CoV-2 viral RNA clearance (OR, 2.95, 95% CI 1.63-5.32, P < 0.001), increased risk of 28-day and in-hospital mortality (OR, 4.90, 95% CI 1.68-14.28, P = 0.004; OR, 5.64, 95% CI 1.95-16.30, P = 0.001, respectively), and acute liver injury (OR, 4.50, 95% CI 2.57-7.85, P < 0.001). Methylprednisolone dose per day and cumulative dose in non-survivors were significantly higher than in survivors. CONCLUSIONS: In patients with severe COVID-19/HBV co-infection, corticosteroid treatment may be associated with increased risk of 28-day and in-hospital mortality.

Isoleucine stimulates mTOR and SREBP-1c gene expression for milk synthesis in mammary epithelial cells through BRG1-mediated chromatin remodelling.

Several amino acids can stimulate milk synthesis in mammary epithelial cells (MEC); however, the regulatory role of isoleucine (Ile) and underlying molecular mechanism remain poorly understood. In this study, we aimed to evaluate the regulatory effects of Ile on milk protein and fat synthesis in MEC and reveal the mediation mechanism of Brahma-related gene 1 (BRG1) on this regulation. Ile dose dependently affected milk protein and fat synthesis, mechanistic target of rapamycin (mTOR) phosphorylation, sterol regulatory element binding protein 1c (SREBP-1c) expression and maturation, and BRG1 protein expression in bovine MEC. Phosphatidylinositol 3 kinase (PI3K) inhibition by LY294002 treatment blocked the stimulation of Ile on BRG1 expression. BRG1 knockdown and gene activation experiments showed that it mediated the stimulation of Ile on milk protein and fat synthesis, mTOR phosphorylation, and SREBP-1c expression and maturation in MEC. ChIP-PCR analysis detected that BRG1 bound to the promoters of mTOR and SREBP-1c, and ChIP-qPCR further detected that these bindings were increased by Ile stimulation. In addition, BRG1 positively regulated the binding of H3K27ac to these two promoters, while it negatively affected the binding of H3K27me3 to these promoters. BRG1 knockdown blocked the stimulation of Ile on these two gene expressions. The expression of BRG1 was higher in mouse mammary gland in the lactating period, compared with that in the puberty or dry period. Taken together, these experimental data reveal that Ile stimulates milk protein and fat synthesis in MEC via the PI3K-BRG1-mTOR/SREBP-1c pathway.

Daidzein stimulates fatty acid-induced fat deposition in C2C12 myoblast cells via the G protein-coupled receptor 30 pathway.

Fat deposition in skeletal muscle is an important aspect of improving meat quality. Isoflavones can promote animal anabolism, but whether and how they regulate muscle fat deposition remain largely unclear. In this study, we explored the role and corresponding molecular mechanism of one of the major isoflavones, daidzein, in fat deposition in C2C12 myoblast cells. In the absence of fatty acids (FAs), daidzein did not promote triglyceride synthesis and lipid droplet formation in cells but increased sterol regulatory element-binding protein 1c (SREBP-1c) expression and maturation. In the presence of FAs, daidzein enhanced FAs-induced fat deposition and the SREBP-1c signaling. Daidzein promoted FAs-induced nuclear factor κB1 (NFκB1) phosphorylation and activated the SREBP-1c signaling in a PI3K-dependent manner. G protein-coupled receptor 30 (GPR30) knockdown but not estrogen receptor α (ERα) knockdown blocked the stimulation of daidzein on the PI3K-NFκB1-SREBP-1c signaling pathway, while both knockdown did not affect the stimulation of FAs on this signaling. qRT-PCR and ChIP-qPCR further detected that daidzein stimulated NFκB1-targeted SREBP-1c transcription. Daidzein did not affect ERα expression in cells, but it stimulated GPR30 expression and cytoplasmic localization. These results reveal that daidzein promotes FAs-induced fat deposition through the GPR30 signaling in C2C12 myoblast cells.

Simultaneous or Prior Activation of Intrahepatic Type I Interferon Signaling Leads to Hepatitis B Virus Persistence in a Mouse Model.

It remains controversial how interferon (IFN) response contributes to hepatitis B virus (HBV) control and pathogenesis. A previous study identified that hydrodynamic injection (HI) of type I IFN (IFN-I) inducer polyinosinic-poly(C) [poly(I·C)] leads to HBV clearance in a chronic HBV mouse model. However, recent studies have suggested that premature IFN-I activation in the liver may facilitate HBV persistence. In the present study, we investigated how the early IFN-I response induces an immunosuppressive signaling cascade and thus causes HBV persistence. We performed HI of the plasmid adeno-associated virus (pAAV)/HBV1.2 into adult BALB/c mice to establish an adult acute HBV replication model. Activation of the IFN-I signaling pathway following poly(I·C) stimulation or murine cytomegalovirus (MCMV) infection resulted in subsequent HBV persistence. HI of poly(I·C) with the pAAV/HBV1.2 plasmid resulted in not only the production of IFN-I and the anti-inflammatory cytokine interleukin-10 (IL-10) but also the expansion of intrahepatic regulatory T cells (Tregs), Kupffer cells (KCs), and myeloid-derived suppressor cells (MDSCs), all of which impaired the T cell response. However, when poly(I·C) was injected at day 14 after the HBV plasmid injection, it significantly enhanced HBV-specific T cell responses. In addition, interferon-alpha/beta receptor (IFNAR) blockade rescued T cell response by downregulating IL-10 expression and decreasing Treg and KC expansion. Consistently, Treg depletion or IL-10 blockade also controlled HBV replication. IMPORTANCE IFN-I plays a double-edged sword role during chronic HBV infection. Here, we identified that application of IFN-I at different time points causes contrast outcomes. Activation of the IFN-I pathway before HBV replication induces an immunosuppressive signaling cascade in the liver and consequently caused HBV persistence, while IFN-I activation post HBV infection enhances HBV-specific T cell responses and thus promotes HBV clearance. This result provided an important clue to the mechanism of HBV persistence in adult individuals.

Natural Killer Cells Regulate the Maturation of Liver Sinusoidal Endothelial Cells Thereby Promoting Intrahepatic T-Cell Responses in a Mouse Model.

Functional maturation of liver sinusoidal endothelial cells (LSECs) plays an important role in intrahepatic T-cell activation and control of viral infections. Natural killer (NK) cells have been reported to prompt the maturation of antigen-presenting cells (APCs), especially for dendritic cells (DCs), but the interaction between NK cells and LSECs is elusive. Here, we investigated whether and how NK cells are involved in regulating LSEC maturation and if this has a role in controlling hepatitis B virus (HBV) infection in a mouse model. A chronic HBV replication mouse model was established by hydrodynamic injection (HI) of 6 µg adeno-associated virus plasmid (pAAV)/HBV 1.2. The nucleotide-binding oligomerization domain-containing protein 1 (NOD1) ligand diaminopemelic acid (DAP) was imported into liver by HI at day 14 after plasmid injection. We found that HI of DAP recruited conventional NK cells (cNK) into the liver and promoted tumor necrosis factor alpha (TNF-α) and interferon-gamma (IFN-γ) production of NK cells in a chemokine (C-X-C motif) receptor 3 (CXCR3)-dependent manner. Importantly, the maturation of LSECs and the anti-HBV effects of DAP were impaired in CXCR3-/- mice; this possibly was associated with the decreased number of intrahepatic cNK cells. Consistently, depleting cNK cells but not liver-resident NK cells also impaired the maturation and antigen-presenting function of LSECs, which reduced intrahepatic HBV-specific T-cell responses and thus inhibited HBV clearance both in wild-type and in Rag1-/- mice. Moreover, TNF-α or IFN-γ stimulation as well as coculture with intrahepatic NK cells partly promoted LSEC phenotypic and functional maturation in vitro. Conclusion: NOD1-triggered NK cell activation may lead to the enhancement of intrahepatic T-cell responses by promoting maturation of LSECs through soluble cytokines and cell-cell contact, thereby controlling HBV replication and expression.

Development and evaluation of a novel loop mediated isothermal amplification coupled with TaqMan probe assay for detection of genetically modified organism with NOS terminator.

In this study, we aim to develop a novel loop mediated isothermal amplification (LAMP) coupled with TaqMan (LAMP-TaqMan) method for quick qualitative detection of genetically modified organism (GMOs). We designed four LAMP primers and one TaqMan probe for the LAMP-TaqMan detection method to detect the nopaline synthase gene (NOS) terminator in GMOs. This assay enabled the amplification of DNA within ~20 min at a constant temperature of 65 °C. This assay detected as few as five copies of target sequences, which had a high specificity similar to the TaqMan qPCR method. Furthermore, the LAMP-TaqMan detection method was successfully used to amplify and detect DNA from food samples of the major crops (soybean, maize, rice, etc.). In summary, a novel LAMP-TaqMan assay has been developed, which has the similar sensitivity but takes less time than the TaqMan qPCR method. This method offers a novel approach for rapid detection of GMOs in foods.

Delivery of toll-like receptor 3 ligand poly(I:C) to the liver by calcium phosphate nanoparticles conjugated with an F4/80 antibody exerts an anti-hepatitis B virus effect in a mouse model.

Hepatitis B virus (HBV) is a global health issue, but currently available anti-HBV drugs have limited success. Previously, introduction of the Toll-like receptor (TLR)-3 ligand poly(I:C) to the liver via hydrodynamic injection (HI) was shown to effectively suppress HBV replication in a chronic HBV replication mouse model. However, this method cannot be applied in human beings. To improve the liver targeting of poly(I:C) via intravenous injection, calcium phosphate nanoparticles (CPNs) carrying poly(I:C) with or without antibodies were constructed, and their anti-HBV effects were investigated. We found that significantly more anti-F4/80-conjugated and IgG2α-conjugated nanoparticles were taken up in liver cells both in vivo and in vitro. In addition, these nanoparticles produced pronounced immunostimulatory effects in vitro in primary liver cells. Importantly, treatment with nanoparticles carrying poly(I:C) increased the production of intrahepatic cytokines and chemokines and enhanced T cell responses, significantly reducing HBsAg, HBeAg and HBV DNA levels in the mice. Compared to nonconjugated and isotype-antibody-conjugated nanoparticles, the anti-F4/80-conjugated nanoparticles demonstrated the strongest anti-HBV effects. In summary, nanoparticles carrying poly(I:C) conjugated with an F4/80 antibody promoted liver targeting, and they may represent a suitable alternative to HI for future anti-HBV treatment. STATEMENT OF SIGNIFICANCE: HBV chronically infects approximately 250 million individuals worldwide but current anti-HBV drugs have limited success. Introduction of toll-like receptor 3 ligand poly(I:C) into liver by hydrodynamic injection has been proven to promote HBV clearance in mouse model. However, this technique is not clinically suitable for human patients. We have constructed calcium phosphate nanoparticles carrying poly(I:C) with specific antibody targeting liver nonparenchymal cells. The uptake into relevant liver cells and the anti-HBV effects were studied. After intravenous injection into mice, the uptake rate of anti-F4/80-conjugated nanoparticels was enhanced in liver, and these nanoparticles exert effective anti-HBV effects in vivo. This may provide important insight into future HBV immunotherapy based on nanoparticle-mediated drug delivery.

Immunopathogenesis of HBV Infection.

More than 95% of adult infected with HBV show acute self-limited infection and eventually eliminate the virus. In contrast, about 90% of people exposed to HBV in early childhood develop chronic infection. The specificity of the virus and the host's antiviral immune responses together determine the outcome of HBV infection. It is generally believed that viral genome variation, viral titers, and inhibition of viral components against the host immune system are associated with persistent infection and liver damage. The dysfunction of innate immune cells (NK cells, monocyte/macrophages, NKT cells, etc.) and adaptive immune cells (antigen-presenting cells, T cells, B cells) is a key factor leading to virus clearance failure and liver inflammation. In this chapter, we summarize these viral factors and host factors in acute and chronic hepatitis B and update recent understanding of the immune-tolerant phase and pathological mechanisms associated with age and vertical transmission. This will help us to understand more fully the mechanisms of chronic HBV infection and liver injury and to develop combined treatment strategies of direct antiviral drugs for HBV life cycle and immunomodulators.

Pattern Recognition Receptors and Liver Failure.

Liver failure is a clinical syndrome with many causes, a complicated pathogenesis, diverse clinical manifestations, and very high mortality. No effective treatment is yet available. Main pathological processes of liver failure include direct damage to parenchymal and nonparenchymal liver cells that might be caused by viruses or drugs, immune-mediated indirect damage, inflammation, and ischemia-hypoxia injury that further strengthen liver damage and lead to endotoxemia. Among these causes, viral or bacterial components (called pathogen-associated and damage-associated molecular patterns) are released during tissue damage and cell death and may be recognized by pattern recognition receptors (PRRs) to induce secretion of inflammatory cytokines and chemokines and activate immune cells. This process is an important mechanism that underlies the progression of liver failure. Research concerning the roles of PRR signaling pathways in liver failure is expected to result in development of immunomodulatory drugs to target specific disease stages, immune cells, and signal transduction molecules. This article briefly introduces the research status of six main PRRs (Toll-like receptors, nucleotide-binding oligomerization domain-like receptors, retinoic-acid-inducible gene I-like receptors, cytosolic DNA sensors, C-type lectin receptors, and inflammasomes) in acute liver failure and acute-on-chronic liver failure and explores further research directions.