Characterization of a pangolin SARS-CoV-2-related virus isolate that uses the human ACE2 receptor.

Various SARS-CoV-2-related coronaviruses have been increasingly identified in pangolins, showing a potential threat to humans. Here we report the infectivity and pathogenicity of the SARS-CoV-2-related virus, PCoV-GX/P2V, which was isolated from a Malayan pangolin (Manis javanica). PCoV-GX/P2V could grow in human hepatoma, colorectal adenocarcinoma cells, and human primary nasal epithelial cells. It replicated more efficiently in cells expressing human angiotensin-converting enzyme 2 (hACE2) as SARS-CoV-2 did. After intranasal inoculation to the hACE2-transgenic mice, PCoV-GX/P2V not only replicated in nasal turbinate and lungs, but also caused interstitial pneumonia, characterized by infiltration of mixed inflammatory cells and multifocal alveolar hemorrhage. Existing population immunity established by SARS-CoV-2 infection and vaccination may not protect people from PCoV-GX/P2V infection. These findings further verify the hACE2 utility of PCoV-GX/P2V by in vivo experiments using authentic viruses and highlight the importance for intensive surveillance to prevent possible cross-species transmission.

Locus 5p13.1 may be associated with the selection of cancer-related HBV core promoter mutations.

Background: The basal core promoter (BCP) double mutations (A1762T and G1764A) of hepatitis B virus (HBV) have been reported to be an aetiological factor of hepatocellular carcinoma (HCC). What distinguishes the subset of HBV carriers in whom these mutations are selected? Methods: A genome-wide association study (GWAS) was carried out on 218 asymptomatic HBsAg carriers infected with HBV with BCP double mutations and 191 controls infected with HBV with the wild type BCP. The highest ranking nucleotide polymorphisms (SNPs) were validated with other study subjects, 203 cases and 181 controls. The expression of the gene nearest a SNP found to be significant was examined using RT-PCR. Results: Forty-five candidate SNPs were identified in the GWAS. Three SNPs were found to be associated with the selection of HBV BCP double mutations in the replication stage, including rs7717457 at 5p13.1, rs670011 at 17q21.2, rs2071611 at 6p22.2. Especially, rs7717457 (P= 4.57×10-5 combined P) reached the potential GWAS significance level. The expression of gene complement component 7 (C7), nearest to SNP rs7717457, differed significantly between the case and control groups (t=2.045, P=0.04), suggesting that SNP rs7717457 was associated with the expression of its nearest gene. Conclusions: SNP rs7717457 is associated with the selection of HBV BCP double mutations, providing an important clue to understanding the mechanisms of oncogenesis of HBV BCP double mutations.

Ursolic acid inhibits breast cancer growth by inhibiting proliferation, inducing autophagy and apoptosis, and suppressing inflammatory responses via the PI3K/AKT and NF-κB signaling pathways in vitro.

Breast cancer, which is the second leading cause of cancer-associated mortality in women worldwide, develops from breast tissue. Chemotherapy is the most commonly used therapy to treat breast cancer. However, a number of natural plant-derived products have been suggested as alternative therapies to treat different types of cancer, such as breast cancer. The aim of the present study was to determine the anti-tumor effects of ursolic acid and its effect on apoptosis and inflammation in breast cancer cells. The anti-cancer effects of ursolic acid were evaluated in vitro using flow cytometry, western blotting and reverse transcription-quantitative polymerase chain reaction. The results suggest that ursolic acid inhibits the viability of breast cancer cells by inducing autophagy and apoptosis without inducing cell death. Cellular migration assays demonstrated that ursolic acid was able to suppress the invasive ability of breast cancer cells (P<0.05). In addition, the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) pathway was downregulated following ursolic acid administration (P<0.05), leading to an upregulation of glycogen synthase kinase activity (P<0.05) and downregulation of B-cell lymphoma 2 (P<0.05), subsequently causing autophagy and apoptosis via cyclin-D1 inhibition and caspase-3 stimulation (P<0.05). Furthermore, the inflammatory response of breast cancer cells was assessed by measuring levels of nuclear factor (NF)-κB. Ursolic acid was found to downregulate NF-κB in breast cancer cells, thus inhibiting inflammation and preventing the progression of breast cancer (P<0.05). To the best of our knowledge, the present study is the first to assess the effect of ursolic acid on breast cancer cells through PI3K/AKT-regulated GSK and caspase-3 accompanied by NF-κB signaling pathways. The results of the present study regarding the potential underlying molecular mechanisms of ursolic acid may be used to develop novel therapeutic strategies for breast cancer treatment.

The inhibiting effect of the transcription factor p53 on dengue virus infection by activating the type I interferon.

To investigate the role of the transcription factor p53 in the course of the dengue virus (DV) infection. The human hepatocellular carcinoma cell strain HepG2 with a low expression level of p53 was built by using the retroviral-mediated RNA interference technology, and was detected by Western blot. The wild group and the interference group were respectively infected by the type 2 DV. The viral titration was detected by the Vero plaque assay, the viral multiplication was detected by the immunofluorescence, the cell apoptosis after virus infection was detected by FCM and the level of IFN-ß was analyzed by ELISA. Compared to the wild group, the expression level of p53 in the interference group decreased significantly, which indicated that the HepG2 cell strain with the low expression level of p53 was successfully built. 24h after DV infection, the virus titration in the interference group was 100 times higher than that in the wild group. The result of the immunofluorescence showed that, the amount of green fluorescent cells in the interference group was significant higher than that in the wild group. It was indicated that the DV infection was inhibited by p53. However, 24h after DV infection, there was no significant difference in the amount of apoptotic cells in both groups. And the amount of IFN-ß in the wild group increased 6 times. The DV infection was inhibited by the transcription factor p53 by activating type I interferon pathway other than promoting the cell apoptosis.

Relationships between cell cycle pathway gene polymorphisms and risk of hepatocellular carcinoma.

AIM: To investigate the associiations between the polymorphisms of cell cycle pathway genes and the risk of hepatocellular carcinoma (HCC). METHODS: We enrolled 1127 cases newly diagnosed with HCC from the Tumor Hospital of Guangxi Medical University and 1200 non-tumor patients from the First Affiliated Hospital of Guangxi Medical University. General demographic characteristics, behavioral information, and hematological indices were collected by unified questionnaires. Genomic DNA was isolated from peripheral venous blood using Phenol-Chloroform. The genotyping was performed using the Sequenom MassARRAY iPLEX genotyping method. The association between genetic polymorphisms and risk of HCC was shown by P-value and the odd ratio (OR) with 95% confidence interval (CI) using the unconditional logistic regression after adjusting for age, sex, nationality, smoking, drinking, family history of HCC, and hepatitis B virus (HBV) infection. Moreover, stratified analysis was conducted on the basis of the status of HBV infection, smoking, and alcohol drinking. RESULTS: The HCC risk was lower in patients with the MCM4 rs2305952 CC (OR = 0.22, 95%CI: 0.08-0.63, P = 0.01) and with the CHEK1 rs515255 TC, TT, TC/TT (OR = 0.73, 95%CI: 0.56-0.96, P = 0.02; OR = 0.67, 95%CI: 0.46-0.97, P = 0.04; OR = 0.72, 95%CI: 0.56-0.92, P = 0.01, respectively). Conversely, the HCC risk was higher in patients with the KAT2B rs17006625 GG (OR = 1.64, 95%CI: 1.01-2.64, P = 0.04). In addition, the risk was markedly lower for those who were carriers of MCM4 rs2305952 CC and were also HBsAg-positive and non-drinking and non-smoking (P < 0.05, respectively) and for those who were carriers of CHEK1 rs515255 TC, TT, TC/TT and were also HBsAg-negative and non-drinking (P < 0.05, respectively). Moreover, the risk was higher for those who were carriers of KAT2B rs17006625 GG and were also HBsAg-negative (P < 0.05). CONCLUSION: Of 12 cell cycle pathway genes, MCM4, CHEK1 and KAT2B polymorphisms may be associated with the risk of HCC.

Effect of rAAV2-hTGFß1 Gene Transfer on Matrix Synthesis in an In Vivo Rabbit Disk Degeneration Model.

STUDY DESIGN: In vivo gene transfer for disk regeneration. OBJECTIVE: To evaluate the efficiency and effect of human transforming growth factor ß1 (hTGFß1) gene transfer mediated by adeno-associated virus (AAV) in a rabbit disk degeneration model induced by fibronectin fragment (Fn-f). SUMMARY OF BACKGROUND DATA: Gene therapy for disk degeneration has been reported to be effective. Nevertheless, few investigations have targeted the degenerative nucleus pulposus (NP) cells in vivo. Fn-f-induced degeneration has been previously verified to be a useful model for the study of disk degeneration at the molecular level. AAV vector is well suited for gene transfer in the disk for its lower immunogenicity and higher safety. MATERIALS AND METHODS: The early dedifferentiated NP cells were transfected with rAAV2-mediated enhanced green fluorescent protein (EGFP) gene in vitro. Fluorescence expression was observed 48 hours later. The rabbit disk degeneration model was established with a microinjection of Fn-f. Ninety-six degenerative disks of 24 rabbits were injected with rAAV2-hTGFß1 (group A), rAAV2-EGFP (group B), or PBS (group C). Immunohistochemical staining for hTGFß1 and fluorescence observation were performed at the 1- and 12-week time points, respectively. 35S-sulfate incorporation assay and Western blot analysis were used to measure the synthesis of proteoglycan and collagen type II at 4-, 8-, and 12-week time points. RESULTS: The dedifferentiated NP cells exhibited intensive fluorescence expression in vitro, with a transfection rate of 90%. In vivo, disks in group A showed enhanced positive hTGFß1 immunostaining at the 1-week time point. At the 4-, 8-, and 12-week time points, disks in group A exhibited significantly increased proteoglycan and collagen type II synthesis compared with the other 2 groups (P<0.01). Abundant green fluorescence was observed in the disks in group B at the 12-week time point. CONCLUSIONS: Early degenerative NP cells are susceptible to AAV-mediated gene transfer in vitro and in vivo. The rapid and prolonged target protein expressions and increased matrix synthesis indicated that AAV-mediated therapeutic gene transfer can be a promising form of treatment for disk regeneration in vivo.

Rosmarinic Acid Attenuates Sodium Taurocholate-Induced Acute Pancreatitis in Rats by Inhibiting Nuclear Factor-κB Activation.

Rosmarinic Acid (RA), a caffeic acid ester, has been shown to exert anti-inflammation, anti-oxidant and antiallergic effects. Our study aimed to investigate the effect of RA in sodium taurocholate ( NaTC )-induced acute pancreatitis, both in vivo and in vitro. In vivo, RA (50 mg/kg) was administered intraperitoneally 2 h before sodium taurocholate injection. Rats were sacrificed 12 h, 24 h or 48 h after sodium taurocholate injection. Pretreatment with RA significantly ameliorated pancreas histopathological changes, decreased amylase and lipase activities in serum, lowered myeloperoxidase activity in the pancreas, reduced systematic and pancreatic interleukin-1 ß (IL-1ß), IL-6, and tumor necrosis factor-α (TNF-α) levels, and inhibited NF-κB translocation in pancreas. In vitro, pretreating the fresh rat pancreatic acinar cells with 80 µ mol/L RA 2 h before 3750 nmol/L sodium taurocholate or 10 ng/L TNF-α administration significantly attenuated the reduction of isolated pancreatic acinar cell viability and inhibited the nuclear activation and translocation of NF-κB. Based on our findings, RA appears to attenuate damage in sodium taurocholate-induced acute pancreatitis and reduce the release of inflammatory cytokines by inhibiting the activation of NF-κB. These findings might provide a basis for investigating the therapeutic role of RA in managing acute pancreatits.

Tetraspanin CD9 is involved in pancreatic damage during caerulein-induced acute pancreatitis in mice.

OBJECTIVE: Pancreatic acinar cell necrosis and subsequent inflammatory response aggravate acute pancreatitis (AP). Tetraspanin CD9 has been reported to mediate inflammatory signaling by regulating molecular organization at the cell surface. This study aimed to investigate the role of CD9 in caerulein-induced AP (CIP) in mice. METHODS: The expression of CD9 was detected in CIP in mice in vivo and cholecystokinin (CCK)/recombinant mouse tumor necrosis factor (rmTNF)-α induced pancreatic acinar cell death in vitro by quantitative real-time polymerase chain reaction, Western blot and immunofluorescence. The roles of CD9 in pancreatic acinar cell death and inflammatory response were further studied through the deletion of CD9 expression using small interfering RNA (siRNA). RESULTS: CD9 was markedly upregulated in pancreatic tissues in mice during the early onset of CIP and was located mainly at the pancreatic acinar cell surface, which was associated with pancreatic damage. Additionally, incubation with CCK or rmTNF-α directly increased the expression of CD9 in isolated mice pancreatic acinar cells in vitro. The deletion of CD9 expression partially reversed both pancreatic acinar cell death induced by CCK and mRNA levels of proinflammatory cytokines produced by damaged acinar cells. CONCLUSION: These results indicate that increased CD9 expression may be involved in pancreatic injury, possibly via the promotion of cytokine expressions in CIP in mice.

Catalpol ameliorates sodium taurocholate-induced acute pancreatitis in rats via inhibiting activation of nuclear factor kappa B.

Catalpol, an iridoid glucoside extracted from the traditional Chinese herbal medicine, Rehmannia glutinosa, is reported to exert neuroprotective, anti-inflammatory, anti-tumor and anti-apoptotic effects. The main aim of the present study was to investigate whether catalpol ameliorates experimental acute pancreatitis (AP) induced by sodium taurocholate (STC). AP was induced in rats via retrograde injection of 4% STC (0.1 mL/100 g) into the biliopancreatic duct. Rats were pre-treated with saline or catalpol (50 mg/kg) 2 h before STC injection. At 12, 24 and 48 h after injection, the severity of AP was evaluated using biochemical and morphological analyses. Pretreatment with catalpol led to a significant reduction in serum amylase and lipase activities, pancreatic histological damage, myeloperoxidase (MPO) activity, interleukin (IL)-1ß, IL-6 and TNF-α levels, and activation of nuclear factor kappa B (NF-κB). Moreover, administration of catalpol increased the viability of pancreatic acinar cells and inhibited NF-κB expression in vitro. Our results collectively support the potential of catalpol as a highly effective therapeutic agent for treatment of AP.

[A novel rabbit disc degeneration model induced by fibronectin fragment].

OBJECTIVE: To establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of fibronectin fragment (Fn-f). METHODS: Thirty-two New Zealand white rabbits underwent injection of N-terminal 30 kDa Fn-f (experimental group) or phosphate buffered saline (PBS) (control group) into the central region of L1-2, L2-3, L3-4, L4-5 discs using a 32-gauge microsyringe. Two rabbits (blank group) with no treatments were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically, and with proteoglycan synthesis. RESULTS: Histology demonstrated a progressive loss of the cell numbers in NP and architecture destruction in NP and anulus fibrosus (AF) in Fn-f-injected discs over the 16-week study period. The NP regions in Fn-f-injected discs shrinked distinctly after the 4-week time point, and were not discernible with the inner AF by the 16-week time point. Protoglycan synthesis in Fn-f-injected discs decreased progressively (F = 263.241, P = 0.000). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (t = -27.010 - -2.833, P < 0.05). The DHI% of the Fn-f-injected discs at the 4-, 8-, 12-, and 16-week time points were 96.5% ± 1.7%, 85.6% ± 3.8%, 77.2% ± 3.5% and 65.5% ± 5.6%, respectively. Comparing with the DHI% of PBS-injected discs (97.4% ± 1.2%), the Fn-f-injected discs exihibited no significant differences in disc heights at the 4-week time point (P > 0.05), but significant decreases in disc heights at the 8-, 12-, and 16-week time points (t = -21.225 - -10.795, P < 0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkablely by the 16-week time point in the experimental spines. CONCLUSIONS: Fn-f can induce a progressively degenerative process in rabbit discs which is ethical, cost-effective, reproducible, and consistent with the spontaneous degeneration in human. And it seem to be a novel and useful model for the study of disc degeneration at the molecular level.

Combined detection of serum matrix metalloproteinase 9, acetyl heparinase and cathepsin L in diagnosis of ovarian cancer.

OBJECTIVE: To investigate the clinic values of combining test of serum matrix metalloproteinase 9 (MMP-9), acetyl heparinase (Hpa) and Cathepsin L (CL) in diagnosis of ovarian cancer. METHODS: Serum levels of MMP-9, Hpa and CL were detected in a total of 418 cases, including 217 cases with ovarian malignant tumor, 100 cases with ovarian benign tumor and 101 healthy controls, by using enzyme-linked immunosorbent assay (ELISA). Their correlation with clinicopathologic feature of ovarian malignant tumor was analyzed and their diagnosis performance was evaluated by receiver operating characteristic (ROC). The combined diagnosis model was established by logistic regression analysis. RESULTS: The serum levels of MMP-9, Hpa and CL were significantly higher in patients with ovarian malignant tumor than in benign tumor and healthy control, the serum levels of CL and Hpa were higher in epithelial cancer than in non-epithelial tumor, and MMP-9, Hpa and CL were elevated in low grade and advanced stage compared to high grade and early stage. The sensitivity for diagnosis of ovarian malignant tumor from high to low was CL, Hpa and MMP-9, and the specificity was MMP-9, CL and Hpa. The united diagnosis model was established and showed the sensitivity and specificity of combined detection were 84.6% and 82.1%, respectively, which were significantly higher than a single tumor marker. CONCLUSION: Serum MMP-9, Hpa and CL were correlated with ovarian malignant tumor and the combined detection of which may be valuable for clinical diagnosis of ovarian malignant tumor.

[Second hearing screening model in neonates who failed the first screening].

OBJECTIVE: To study the significance of the second hearing screening in neonates who failed the first screening during their hospital stay. METHODS: Screening TEOAE tests were employed in 3849 neonates. The first screen was 3 days after birth. Those who failed were rescreened before discharge (5 - 7 days after birth). Neonates who failed the second screening would have a third screening in 30 - 42 days. Four types of rates were compared: pass rates of three times, rates of single ear fail and double ear fail, pass rates of left ear and right ear, pass rates of Caesarean birth and that of natural labor. RESULTS: The difference between rates of first time and second time is statistically significant (χ(2) = 38.67, P < 0.01). There is no statistically difference between the total pass rate in ward and that of third time (χ(2) = 2.73, P > 0.05). The pass rate of single ear fail is higher than that of double ears (χ(2) = 34.34, P < 0.01, the difference has statistical significance). The pass rate of left ear is higher than that of right ear (χ(2) = 0.62, P > 0.05, the difference has not statistical significance). The first time screen result showed pass rates of natural labor is higher than that of Caesarean birth (χ(2) = 35.37, P < 0.05), but the differences of pass rates of the second and third time between two delivery method was no statistical significance (P > 0.05). CONCLUSION: Two times of screening in ward could decrease false negative and refer rate, thus relieve parent's mental burden.

Adenovirus 11p downregulates CD46 early in infection.

Adenovirus 11 prototype (Ad11p), belonging to species B, uses CD46 as an attachment receptor. CD46, a complement regulatory molecule, is expressed on all human nucleated cells. We show here that Ad11p virions downregulate CD46 on the surface of K562 cells as early as 5min p.i. Specific binding to CD46 by the Ad11p fiber knob was required to mediate downregulation. The complement regulatory factors CD55 and CD59 were also reduced to a significant extent as a consequence of Ad11p binding to K562 cells. In contrast, binding of Ad7p did not result in downregulation of CD46 early in infection. Thus, the presumed interaction between Ad7p and CD46 did not have the same consequences as the Ad11p-CD46 interaction, the latter virus (Ad11p) being a promising gene therapy vector candidate. These findings may lead to a better understanding of the pathogenesis of species B adenovirus infections.

Preliminary separation of the growth factors in platelet-rich plasma: effects on the proliferation of human marrow-derived mesenchymal stem cells.

BACKGROUND: Platelet-rich plasma (PRP) as a storage vehicle of growth factors has been successfully used in clinical applications, but in most cases the platelets were autologous. However, the large volume of blood withdrawn has detrimental effects on patients with anemia or poor general health. To overcome these limitations, this study was designed to separate the growth factors in homologous platelet-rich plasma. METHODS: The gel chromatography with Superdex-75 column was applied to separate PRP supernatants into 4 major fractions. Then the four fractions were vacuumed freeze-dried and re-dissolved in phosphate buffered saline. Proteins concentrations in PRP and in four fractions were detected by bicinchoninic acid protein assay; platelet derived growth factor-AB (PDGF-AB) and transforming growth factor beta1 (TGF-beta1) levels were determined by sandwich enzyme-linked immunosorbent assays. The effects of fractions on the proliferation of human marrow-derived mesenchymal stem cells (MSCs) were determined by 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: PRP supernatants were separated into four major fractions by gel chromatography. The proteins recovery was 96.72%. Of the four fractions, fraction B contained the highest TGF-beta1 and PDGF-AB levels, and the highest proteins concentrations. Cell proliferation curves of MSC demonstrated that fraction B and C induced a remarkable increase of MTT values compared to the untreated culture (P < 0.05), and the effects of fraction B and C showed no significant difference compared to the PRP group (P > 0.05). Fraction A and D showed no significant difference to the negative control group (P > 0.05). CONCLUSIONS: The growth factors in PRP supernatants could be preliminarily separated into four fractions by gel chromatography, and the freeze-drying fractions retained the biological activity of growth factors. The growth factors were mostly presented in fraction B and C, and they promoted cell proliferation effectively.

[Soil enzyme activities under two forest types as affected by different levels of nitrogen deposition].

A simulation test was conducted to study the change trends of soil cellulase, polyphenol oxidase, and sucrase activities under natural broadleaf-Korean pine (Pinus koraiensis) and secondary poplar (Populus davidiana) -birch (Betula platyphylla) mixed forests as affected by 0, 25, and 50 kg x hm(-2) x a(-1) of N deposition. The results showed that the effects of elevated N deposition on test enzyme activities varied with forest type, and short-term nitrogen addition could significantly affect the test enzyme activities. High N deposition decreased soil polyphyneol oxidase activity, and correspondingly, soil cellulase and sucrase activities also had a trend of decrease.