circular RNA circ-231 promotes protein biogenesis of TPI1 and PRDX6 through mediating the interaction of eIF4A3 with STAU1 to facilitate unwinding of secondary structure in 5' UTR, enhancing progression of human esophageal squamous cell carcinoma (ESCC).

Background: The nuclear cap-binding complex (CBC)-dependent translation (CT) is an important initial translation pathway for 5'-cap-dependent translation in normal mammal cells. Eukaryotic translation initiation factor 4A-III (eIF4A3), as an RNA helicase, is recruited to CT complex and enhances CT efficiency through participating in unwinding of secondary structure in the 5' UTR. However, the detailed mechanism for eIF4A3 implicated in unwinding of secondary structure in the 5' UTR in normal mammal cells is still unclear. Specially, we need to investigate whether the kind of mechanism in normal mammal cells extrapolates to cancer cells, e.g. ESCC, and further interrogate whether and how the mechanism triggers malignant phenotype of ESCC, which are important for identifying a potential therapeutic target for patients with ESCC. Methods: Bioinformatics analysis, RNA immunoprecipitation and RNA pulldown assays were performed to detect the interaction of circular RNA circ-231 with eIF4A3. In vitro and in vivo assays were performed to detect biological roles of circ-231 in ESCC. RNA immunoprecipitation, RNA pulldown, mass spectrometry analysis and co-immunoprecipitation assays were used to measure the interaction of circ-231, eIF4A3 and STAU1 in HEK293T and ESCC. In vitro EGFP reporter and 5' UTR of mRNA pulldown assays were performed to probe for the binding of circ-231, eIF4A3 and STAU1 to secondary structure of 5' UTR. Results: RNA immunoprecipitation assays showed that circ-231 interacted with eIF4A3 in HEK293T and ESCC. Further study confirmed that circ-231 orchestrated with eIF4A3 to control protein expression of TPI1 and PRDX6, but not for mRNA transcripts. The in-depth mechanism study uncovered that both circ-231 and eIF4A3 were involved in unwinding of secondary structure in 5' UTR of TPI1 and PRDX6. More importantly, circ-231 promoted the interaction between eIF4A3 and STAU1. Intriguingly, both circ-231 and eIF4A3 were dependent on STAU1 binding to secondary structure in 5' UTR. Biological function assays revealed that circ-231 promoted the migration and proliferation of ESCC via TPI1 and PRDX6. In ESCC, the up-regulated expression of circ-231 was observed and patients with ESCC characterized by higher expression of circ-231 have concurrent lymph node metastasis, compared with control. Conclusions: Our data unravels the detailed mechanism by which STAU1 binds to secondary structure in 5' UTR of mRNAs and recruits eIF4A3 through interacting with circ-231 and thereby eIF4A3 is implicated in unwinding of secondary structure, which is common to HEK293T and ESCC. However, importantly, our data reveals that circ-231 promotes migration and proliferation of ESCC and the up-regulated circ-231 greatly correlates with tumor lymph node metastasis, insinuating that circ-231 could be a therapeutic target and an indicator of risk of lymph node metastasis for patients with ESCC.

Improvement of rat hepatocellular carcinoma model induced by diethylnitrosamine.

OBJECTIVE: To construct a new diethylnitrosamine (DEN)-induced rat hepatocellular carcinoma (HCC) model with short induction time, high incidence, and survival rate. METHODS: 60 male Sprague-Dawley rats were randomly divided into 4 groups: the control group, the model A (MA) group, the model B (MB) group, and the model C (MC) group. The control group was intraperitoneally injected with 0.9% saline for 6 weeks. The MA group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks. The MB group was injected with the DEN solution at 30 mg/kg three times a week for 6 weeks, and discontinued the induction for 2 weeks. The MC group was injected with the DEN solution at 30 mg/kg three times a week for 8 weeks. The levels of albumin (ALB), alanine transaminase (ALT), and aspartate aminotransferase (AST) in serum were assayed. Meanwhile, the pathological conditions, apoptosis of hepatocytes, expression of NF-κBp65, and the reactive oxygen species level were detected. RESULTS: All rats in the control group and the MA group survived, and none of the rats occurred HCC. HCC occurred in rats of the MB group and the MC group. The serum ALB level in the MB group was higher than that in the MC group. The serum ALT and AST levels and the number of proliferating and apoptotic hepatocyte cells in the MB group were lower than those in the MC group. The expression of ROS- and NF-κBp6- positive cells in the MA group, MB group, and MC group were significantly higher than that of the control group. CONCLUSION: This study developed a new DEN-induced rat HCC model with short induction time, high incidence, and survival rate. NF-κB pathway may be one of the main pathways involved in the development of this model.

A Two-Step Method for Percutaneous Transhepatic Choledochoscopic Lithotomy.

Intrahepatic and extrahepatic choledocholithiasis is a challenge in the field of biliary surgery. We present our experience using a two-step percutaneous transhepatic choledochoscopic lithotomy (PTCSL) procedure to treat challenging biliary stones. We retrospectively reviewed 81 patients with intrahepatic and extrahepatic choledocholithiasis treated using this two-step PTCSL from January 2013 to January 2020, including 40 males and 41 females, with an average age of 66 years. In contrast to traditional percutaneous transhepatic cholangioscopy (PTCS), a channel was established directly through a 16F Amplatz sheath, and the stone in the channel was removed with the aid of a nephroscope. The clinical efficacy and complications of all patients were analyzed. Eighty-one patients (81/81, 100%) had their biliary stones successfully removed; 62/81 patients (76.5%) had biliary stones completely removed after the first operation; 17/81 patients (21%) underwent a second operation; 2/81 patients (2.5%) needed a third operation to completely remove the stones. The incidence of severe bleeding during the operation was 0%, and there were no deaths. The use of the two-step PTCSL method is safe and efficacious, and contributes to a better prognosis of intrahepatic and extrahepatic choledocholithiasis.

Intravenous Immunoglobulin Inhibits Liver Cancer Progression by Promoting p38MAPK-Associated Apoptosis.

Objective: The aim of this study is to explore the effect of intravenous immunoglobulin (IVIG) on the development of rat hepatocellular carcinoma and its possible molecular mechanism. Methods: Sixty adult male Sprague-Dawley (SD) rats were randomly divided into three groups: control, diethylnitrosamine(DEN) + normal saline(NS), and DEN + IVIG groups, with 20 rats in each group. The rats in the DEN + NS group and DEN + IVIG group were given DEN 0.2 g/kg intraperitoneal injection once on day 1 and then 0.05% DEN aqueous solution in drinking water to establish a rat liver cancer model. Immunoglobulin (IgG) was injected intraperitoneally into the DEN + IVIG group twice a week at the dose of 100 mg/kg, and saline was administered intraperitoneally into the control group at a 50 mg/kg dosage. The body weight of each group of rats was recorded twice a week. All treatments were maintained continuously for 12 weeks. After the intervention, the liver function indexes of rats were measured by a fully automated biochemical analysis instrument. The liver histopathology was observed by hematoxylin-eosin(HE) staining. Immunohistochemistry was used to detect c-myc protein expression, and Western blotting was used to determine p38MAPK and p-p38MAPK protein expressions, as well as apoptosis-related proteins such as Bcl-2, Bax, and cleaved caspase-3. Results: Compared with the rats in the DEN + NS group, rats in the DEN + IVIG group showed substantially higher body mass (P < 0.05), higher survival rate (P < 0.05), and lower liver function indexes (P < 0.05). Few focal necrosis of cancer cells and few nuclear division were observed in the rats in the DEN + IVIG group. The rats in the DEN + NS group showed lamellar necrosis of cancer foci, destruction of normal liver lobular structure, and hepatocellular carcinoma cells. Immunohistochemical analysis results revealed that the expression of c-myc was reduced in the DEN + IVIG group (P < 0.05), and Western blotting confirmed that the Bcl-2 expression was decreased (P < 0.05), while Bax, p38 MAPK, p-p38 MAPK, and cleaved caspase-3 protein expressions were increased (P < 0.05). Conclusion: IVIG prophylactic injection can delay tumor development and induce apoptosis in primary hepatocellular carcinoma in rats. The mechanism is connected to the activation of the p38MAPK signaling pathway by upregulating the level of cleaved caspase-3 and Bax proteins while downregulating the level of Bcl-2 and c-myc proteins.

Intravenous immunoglobulin is effective in alleviating hepatic ischemia-reperfusion injury: a rat model study.

BACKGROUND: Hepatic ischemia-reperfusion injury (I/R) is an important factor affecting the prognosis of patients undergoing liver surgery. This study aimed to explore the value of intravenous immunoglobulin (IVIG) in hepatic I/R and its mechanism in a rat model. MATERIALS AND METHODS: Forty eight adult male Sprague-Dawley (SD) rats were divided into six groups randomly: (1-2) treated with normal saline (NS) without ischemia or reperfusion; (3-4) treated with NS + 30 min ischemia; (5-6) treated with IVIG + 30 min ischemia. Rats of group 1/3/5 were euthanized at 12 h after operation (sham + NS + 12 h, I/R + NS + 12 h, I/R + IVIG + 12 h group) while group 2/4/6 were euthanized at 24 h (sham + NS + 24 h, I/R + NS + 24 h, I/R + IVIG + 24 h group). Interleukin 10 (IL-10), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) were quantified as well as serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Hepatic pathological changes were observed while nuclear factor kappa B p65 (NF-κB p65), Inhibitory Subunit of NF Kappa B Alpha (IKB-alpha) and cleaved caspase-3 were detected. CONCLUSION: ALT, AST, IL-6, TNF-alpha, NF-κB p65 and cleaved caspase-3 were increased by I/R whereas IL-10 and IKB-alpha were decreased. However, IVIG pretreatment reduced ALT, AST, IL-6, TNF-alpha, NF-κB p65 and cleaved caspase-3, but increased IL-10 and IKB-alpha. IVIG treatment attenuates the infiltration of inflammatory cell and cell apoptosis which were observed in I/R groups. IVIG may alleviate hepatic I/R in rats by inhibiting the classical NF-κB signaling pathway, reducing IL-6, TNF-alpha, promoting IL-10, and inhibiting cell apoptosis.

Percutaneous Transhepatic Choledochoscopic Lithotomy (PTCSL) is Effective for the Treatment of Intrahepatic and Extrahepatic Choledocholithiasis.

BACKGROUND: To explore percutaneous transhepatic choledochoscopic lithotomy (PTCSL) as a treatment for intrahepatic and extrahepatic choledocholithiasis. PATIENT AND METHODS: A retrospective review of 67 patients with intrahepatic and extrahepatic choledocholithiasis treated by PTCSL from January 2014 to January 2019, including 36 males and 31 females, with an average age of 66 years. During the operation, the doctor established a channel through a 16-Fr Amplatz sheath and removed the stone in the channel with the aid of nephroscope. The clinical efficacy and complications of all patients were analyzed. RESULTS: Sixty-seven patients (67/67, 100%) had their stones successfully removed in the first operation. Only 2 patients (2/67, 3.0%) developed mild reactive pleural effusion after the operation, and 1 patient (1/67, 1.5%) with cholangiocarcinoma after the operation. The incidence of severe bleeding during the operation was 0%. CONCLUSION: PTCSL is a minimally invasive, simple, effective and easy to repeat procedure for use in the clinic. It is an effective surgical treatment and is worthy of clinical use.

NMR-based metabolomic techniques identify potential urinary biomarkers for early colorectal cancer detection.

Better early detection methods are needed to improve the outcomes of patients with colorectal cancer (CRC). Proton nuclear magnetic resonance spectroscopy (1H-NMR), a potential non-invasive early tumor detection method, was used to profile urine metabolites from 55 CRC patients and 40 healthy controls (HCs). Pattern recognition through orthogonal partial least squares-discriminant analysis (OPLS-DA) was applied to 1H-NMR processed data. Model specificity was confirmed by comparison with esophageal cancers (EC, n=18). Unique metabolomic profiles distinguished all CRC stages from HC urine samples. A total of 16 potential biomarker metabolites were identified in stage I/II CRC, indicating amino acid metabolism, glycolysis, tricarboxylic acid (TCA) cycle, urea cycle, choline metabolism, and gut microflora metabolism pathway disruptions. Metabolite profiles from early stage CRC and EC patients were also clearly distinguishable, suggesting that upper and lower gastrointestinal cancers have different metabolomic profiles. Our study assessed important metabolomic variations in CRC patient urine samples, provided information complementary to that collected from other biofluid-based metabolomics analyses, and elucidated potential underlying metabolic mechanisms driving CRC. Our results support the utility of NMR-based urinary metabolomics fingerprinting in early diagnosis of CRC.

Immunoglobulin G promotes skin graft acceptance in an immunologically potent rat model.

Immunoglobulin G (IgG) has been shown to protect graft rejection after transplantation, whereas the molecular mechanism of IgG in promoting graft acceptance has not been well established. In this study, we tested the effectiveness of IgG in preventing rejection of transplanted skin graft in an immunologically potent rat model, and studied the mechanism of this protection. We found that systemic or local administration of IgG significantly prolonged the survival of skin grafts with the immune tolerance induced by IgG and subcutaneous local injection of 1mg IgG to adult SD rat yielded the longest survival of skin grafts from 5.8 to 17.3 days. We also found that IgG reduced the number of pro-inflammatory cells especially lymphocytes, neutrophils and basophils, increased the seral levels of anti-inflammatory factors including IL-10 and IL-4, and activated CD4+CD25+Foxp3+ regulatory T cells, unveiling the mechanisms of this protective effect. These findings provide new insight to support clinical application of IgG in treating transplantation.

Fractionation of Fab glycosylated immunoglobulin G with concanavalin A chromatography unveils new structural properties of the molecule.

Concanavalin A (ConA) chromatography has been extensively used to separate asymmetric Immunoglobulin G (IgG), which possesses oligosaccharide attached to one of the two F(ab')2 arms, from symmetric IgG with no glycan attached to Fab fragments. In this study, applying affinity chromatography, silver stain, Western blot and lectin stain techniques, N- linked oligosaccharide attached to Fab fragment was demonstrated to be exposed on the surface of the protein and be accessible by ConA. In contrast, N- linked oligosaccharide attached to asparagine (Asn) 297 of IgG Fc was located in the inside of the natural protein and was inaccessible by ConA. In addition to asymmetric IgG, there are also detectable level of IgG with both F(ab')2 arms glycosylated that has not been reported previously. The discoveries of new basic molecular structure of IgG would have implications in understanding the function and properties of this important immune molecule with clinical applications.

Sialylated immunoglobulin G can neutralize influenza virus infection through receptor mimicry.

Influenza viruses possess a great threat to human health, but there is still no effective drug to deal with the outbreak of possible new influenza subtypes. In this study, we first fractionated sialylated immunoglobulin G (IgG), mainly Fab sialylated fraction, with sambucus nigra agglutinin affinity chromatography. We then demonstrated that sialylated IgG possessed more effective neutralizing activity against 2009 A (H1N1) subtype than that of IgG mixture, and sialosides on the Fab is crucial in this neutralization reaction as when such residues were removed with neuraminidase A digestion the blocking effect was significantly reduced. It appears that sialic acid residues attached to Fab could serve as binding moieties to receptor binding site of influenza virus. These findings indicate that sialylated IgG probably is an effective anti-influenza broad-spectrum drug utilizing its receptor mimicry to competitively inhibit the attachment of influenza viruses with sialic acid receptors on target cells. This property would be particularly useful if it can be applied to prevent newly emerged influenza virus strain infections in future epidemics.

Development of a New Technique for Reconstruction of Hepatic Artery during Liver Transplantation in Sprague-Dawley Rat.

BACKGROUND: Sleeve anastomosis is the most common technique used to rearterialize orthotopic liver transplants (OLT). However, this technique has a number of disadvantages, including difficulty of performance of the technique visually unaided. We herein describe a novel rearterialized OLT model in the rat. MATERIALS AND METHODS: Forty-six male Sprague Dawley rats (300-400 g) were used as donors and recipients. Based on Kamada's cuff technique, the new model involved performing a modified "sleeve" anastomosis between the celiac trunk of the donor and common hepatic artery of the recipient to reconstruct blood flow to the hepatic artery. An additional ten male Sprague Dawley rats underwent liver transplantation without artery reconstruction. Liver grafts were retrieved from the two groups and histological examination was performed following surgery. RESULTS: Total mean operating times were ~42 minutes for the donor liver extraction and 57 minutes for the recipient transplantation. Graft preparation took an additional 15 minutes and the time to fix the arterial bracket was ~3 minutes. During transplantation, the anhepatic phase lasted 18 ± 2.5 min and the artery reconstruction only required ~3 minutes. The patency rate was 94.44% and the 4-week survival rate was 90%. Histology indicated obvious fibrosis in the liver grafts without artery reconstruction, while normal histology was observed in the arterialized graft. CONCLUSIONS: This new method allows for the surgical procedure to be performed visually unaided with good survival and patency rates and represents an alternative model investigating OLT in rats.

Infectious Progeny of 2009 A (H1N1) Influenza Virus Replicated in and Released from Human Neutrophils.

Various reports have indicated that a number of viruses could infect neutrophils, but the multiplication of viruses in neutrophils was abortive. Based on our previous finding that avian influenza viral RNA and proteins were present in the nucleus of infected human neutrophils in vivo, we investigated the possibility of 2009 A (H1N1) influenza viral synthesis in infected neutrophils and possible release of infectious progeny from host cells. In this study we found that human neutrophils in vitro without detectable level of sialic acid expression could be infected by this virus strain. We also show that the infected neutrophils can not only synthesize 2009 A (H1N1) viral mRNA and proteins, but also produce infectious progeny. These findings suggest that infectious progeny of 2009 A (H1N1) influenza virus could be replicated in and released from human neutrophils with possible clinical implications.

Direct evidence of sirtuin downregulation in the liver of non-alcoholic fatty liver disease patients.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) has become the most common form of chronic liver disease in the world. Recent studies in cultured cells and mice have shown that sirtuin, especially sirtuin 1 (SIRT1), is a key metabolic sensor for regulating metabolic homeostasis and thus has the potential to ameliorate NAFLD. For the purposes of this study, we hypothesized that the inhibition of sirtuin signaling might contribute to the development of NAFLD. METHODS: Tissue was obtained from hepatectomy specimens (10 samples), and medicolegal autopsies (10 samples). Liver tissue sections were stained with H&E. Expression of sirtuin in liver tissues in NAFLD and control group was investigated by RT-PCR and Western blotting. RESULTS: RT-PCR and Western blotting demonstrated decreased expression of SIRT1, SIRT3, SIRT5, and SIRT6 in the NAFLD group in comparison with the control group. Increased expression of lipogenic genes including sterol regulatory element binding protein-1 (SREBP-1), fatty acid synthase (FASN), and acetyl-CoA carboxylase (ACC) was noted within the NAFLD group. In contrast to the other SIRT genes, the expression of SIRT4 was upregulated. CONCLUSION: Our study provides direct evidence of the downregulation of sirtuin signaling that suppresses lipid synthesis in the liver of NAFLD patients, which may promote NAFLD development.

Expression and distribution of immunoglobulin G in the normal liver, hepatocarcinoma and postpartial hepatectomy liver.

The liver has the extraordinary properties of regeneration and immune tolerance; however, the mechanisms governing these abilities are poorly understood. To address these questions, we examined the possible expression of immunoglobulins in the human and rat liver and the relationship of IgG expression to hepatocyte proliferation, metastasis, apoptosis and immune tolerance. Immunohistochemistry, in situ hybridization, laser-guided microdissection and reverse transcription-PCR were performed to examine the expression of IgG in normal human and rat liver, severe combined immunodeficient mouse (SCID) liver and human liver cancers and corresponding cell lines. Small interfering RNA (siRNA) was transfected into cultured hepatocarcinoma cells to downregulate the expression of IgG heavy chain genes. Cell proliferation and apoptosis were assayed with flow cytometry. Cell metastasis was assayed with a Transwell cell assay. Partial hepatectomy (70%) was performed in rats to examine the relationship between hepatocyte IgG and hepatocyte proliferation. IgG, together with essential enzymes for its synthesis, were expressed in the cytoplasm of hepatocytes of normal adult human and hepatoma patients and rat livers, SCID mouse liver and BRL-3A, L-02 and HepG-2 cell lines. Downregulation of IgG inhibited cell proliferation and metastasis and promoted apoptosis. Postsurgery livers expressed significantly more IgG than the livers before surgery and decreased to the original levels when hepatocytes stopped regeneration. IgA and IgM but not IgD and IgE were also positive in hepatocytes. Our findings demonstrate that normal and malignant hepatocytes are capable of synthesizing immunoglobulin, which has important roles in hepatocyte proliferation, apoptosis and cancer growth with profound clinical implications.