Limited disassembly of cytoplasmic hepatitis B virus nucleocapsids restricts viral infection in murine hepatic cells.

BACKGROUND AND AIMS: Murine hepatic cells cannot support hepatitis B virus (HBV) infection even with supplemental expression of viral receptor, human sodium taurocholate cotransporting polypeptide (hNTCP). However, the specific restricted step remains elusive. In this study, we aimed to dissect HBV infection process in murine hepatic cells. APPROACH AND RESULTS: Cells expressing hNTCP were inoculated with HBV or hepatitis delta virus (HDV). HBV pregenomic RNA (pgRNA), covalently closed circular DNA (cccDNA), and different relaxed circular DNA (rcDNA) intermediates were produced in vitro . The repair process from rcDNA to cccDNA was assayed by in vitro repair experiments and in mouse with hydrodynamic injection. Southern blotting and in situ hybridization were used to detect HBV DNA. HBV, but not its satellite virus HDV, was restricted from productive infection in murine hepatic cells expressing hNTCP. Transfection of HBV pgRNA could establish HBV replication in human, but not in murine, hepatic cells. HBV replication-competent plasmid, cccDNA, and recombinant cccDNA could support HBV transcription in murine hepatic cells. Different rcDNA intermediates could be repaired to form cccDNA both in vitro and in vivo . In addition, rcDNA could be detected in the nucleus of murine hepatic cells, but cccDNA could not be formed. Interestingly, nuclease sensitivity assay showed that the protein-linked rcDNA isolated from cytoplasm was completely nuclease resistant in murine, but not in human, hepatic cells. CONCLUSIONS: Our results imply that the disassembly of cytoplasmic HBV nucleocapsids is restricted in murine hepatic cells. Overcoming this limitation may help to establish an HBV infection mouse model.

Hepatitis B Virus Core Protein Is Not Required for Covalently Closed Circular DNA Transcriptional Regulation.

Hepatitis B virus (HBV) infection is a major health burden worldwide, and currently there is no cure. The persistence of HBV covalently closed circular DNA (cccDNA) is the major obstacle for antiviral trement. HBV core protein (HBc) has emerged as a promising antiviral target, as it plays important roles in critical steps of the viral life cycle. However, whether HBc could regulate HBV cccDNA transcription remains under debate. In this study, different approaches were used to address this question. In synthesized HBV cccDNA and HBVcircle transfection assays, lack of HBc showed no effect on transcription of HBV RNA as well as HBV surface antigen (HBsAg) production in a hepatoma cell line and primary human hepatocytes. Reconstitution of HBc did not alter the expression of cccDNA-derived HBV markers. Similar results were obtained from an in vivo mouse model harboring cccDNA. Chromatin immunoprecipitation (ChIP) or ChIP sequencing assays revealed transcription regulation of HBc-deficient cccDNA chromatin similar to that of wild-type cccDNA. Furthermore, treatment with capsid assembly modulators (CAMs) dramatically reduced extracellular HBV DNA but could not alter viral RNA and HBsAg. Our results demonstrate that HBc neither affects histone modifications and transcription factor binding of cccDNA nor directly influences cccDNA transcription. Although CAMs could reduce HBc binding to cccDNA, they do not suppress cccDNA transcriptional activity. Thus, therapeutics targeting capsid or HBc should not be expected to sufficiently reduce cccDNA transcription. IMPORTANCE Hepatitis B virus (HBV) core protein (HBc) has emerged as a promising antiviral target. However, whether HBc can regulate HBV covalently closed circular DNA (cccDNA) transcription remains elusive. This study illustrated that HBc has no effect on epigenetic regulation of cccDNA, and it does not participate in cccDNA transcription. Given that HBc is dispensable for cccDNA transcription, novel cccDNA-targeting therapeutics are needed for an HBV cure.

Novel function of SART1 in HNF4α transcriptional regulation contributes to its antiviral role during HBV infection.

BACKGROUND & AIMS: Our understanding of the interactions between HBV and its host cells is still quite limited. Spliceosome associated factor 1 (SART1) has recently been found to restrict HCV. Thus, we aimed to dissect its role in HBV infection. METHODS: SART1 was knocked down by RNA interference and over-expressed by lentiviral or adeno-associated virus (AAV) vectors in HBV-infected cell cultures and in vivo in HBV-infected mice. Luciferase reporter assays were used to determine viral or host factor promoter activities, and chromatin immunoprecipitation (ChIP) was used to investigate protein-DNA interactions. RESULTS: In HBV-infected cell cultures, downregulation of SART1 did not affect covalently closed circular HBV DNA but resulted in markedly enhanced HBV RNA, antigen expression and progeny virus production. On the other hand, HBV transcription and replication were significantly inhibited by overexpression of SART1. Similar results were observed in AAV-HBV-infected mice persistently replicating HBV. Inhibition of Janus kinases had no effect on SART1-mediated inhibition of HBV replication. HBV promoter assays revealed that SART1 reduced HBV core promoter activity. By screening known HBV transcription factors, we found that SART1 specifically suppressed the expression of hepatocyte nuclear factor 4α (HNF4α). Luciferase reporter and ChIP assays demonstrated a direct downregulation of HNF4α expression by association of SART1 with the HNF4α proximal P1 promoter element. CONCLUSIONS: We identify SART1 as a novel host factor suppressing HBV cccDNA transcription. Besides its effect on interferon-stimulated genes, SART1 exerts an anti-HBV activity by suppressing HNF4α expression, which is essential for transcription of HBV cccDNA. LAY SUMMARY: Hepatitis B virus (HBV) infects hepatocytes and persists in the form of covalently closed circular DNA (cccDNA), which remains a major obstacle to successful antiviral treatment. In this study, using various HBV models, we demonstrate that the protein SART1 restricts HBV cccDNA transcription by suppressing a key transcription factor, HNF4α.

Pharmacokinetics, Tissue Distribution, and Druggability Prediction of the Natural Anticancer Active Compound Cytisine N-Isoflavones Combined with Computer Simulation.

Cytisine N-methylene-(5,7-dihydroxy-4'-methoxy)-isoflavone (CNF2) is a new compound isolated from the Chinese herbal medicine Sophora alopecuroides. Preliminary pharmacodynamic studies demonstrated its activity in inhibiting breast cancer cell metastasis. This study examined the pharmacokinetics, absolute bioavailability, and tissue distribution of CNF2 in rats, and combined computer-aided technology to predict the druggability of CNF2. The binding site of CNF2 and the breast cancer target human epidermal growth factor receptor-2 (HER2) were examined with molecular docking technology. Next, ACD/Percepta software was used to predict the druggability of CNF2 based on the quantitative structure-activity relationship (QSAR). Finally, a simple and effective HPLC method was used to determine plasma pharmacokinetics and tissue distribution of CNF2 in rats. Prediction and experimental results show that compared with the positive control HER2 inhibitor SYR127063, CNF2 has a stronger binding affinity with HER2, suggesting that its efficacy is stronger; and the structure of CNF2 complies with the Lipinski's Rule of Five and has good drug-likeness. The residence time of CNF2 in rats is less than 4 h, and the metabolic rate is relatively fast; But the absolute bioavailability of CNF2 in rats was 6.6%, mainly distributed in the stomach, intestine, and lung tissues, where the CNF2 contents were 401.20, 144.01, and 245.82 µg/g, respectively. This study constructed rapid screening and preliminary evaluation of active compounds, which provided important references for the development and further research of such compounds.

m6A modification-tuned sphingolipid metabolism regulates postnatal liver development in male mice.

Different organs undergo distinct transcriptional, epigenetic and physiological alterations that guarantee their functional maturation after birth. However, the roles of epitranscriptomic machineries in these processes have remained elusive. Here we demonstrate that expression of RNA methyltransferase enzymes Mettl3 and Mettl14 gradually declines during postnatal liver development in male mice. Liver-specific Mettl3 deficiency causes hepatocyte hypertrophy, liver injury and growth retardation. Transcriptomic and N6-methyl-adenosine (m6A) profiling identify the neutral sphingomyelinase, Smpd3, as a target of Mettl3. Decreased decay of Smpd3 transcripts due to Mettl3 deficiency results in sphingolipid metabolism rewiring, characterized by toxic ceramide accumulation and leading to mitochondrial damage and elevated endoplasmic reticulum stress. Pharmacological Smpd3 inhibition, Smpd3 knockdown or Sgms1 overexpression that counteracts Smpd3 can ameliorate the abnormality of Mettl3-deficent liver. Our findings demonstrate that Mettl3-N6-methyl-adenosine fine-tunes sphingolipid metabolism, highlighting the pivotal role of an epitranscriptomic machinery in coordination of organ growth and the timing of functional maturation during postnatal liver development.

Determination of hyperoside and isoquercitrin in rat plasma by membrane-protected micro-solid-phase extraction with high-performance liquid chromatography.

A novel method, micro-solid-phase extraction based on membrane-protected molecularly imprinted polymer, was developed to extract hyperoside and isoquercitrin in rat plasma. Synthesized hyperoside MIPs were packed in a porous polyether sulfone membrane envelope to perform extraction. The parameters sorbent materials, membrane types, extraction time and desorption conditions were optimized for micro-solid-phase extraction. Under the optimal conditions, correlation coefficients, 0.998 and 0.999, were obtained for hyperoside and isoquercitrin, respectively, with the linear range between 1 and 120 µg/mL. The absolute extraction recoveries from 84.5 to 89.3% were found. The method detection limits of hyperoside and isoquercitrin were 0.24 and 0.22 µg/mL, respectively. Compared with traditional methods, solid-phase extraction, liquid-liquid extraction and protein precipitation, the developed method was simple, highly efficient for extraction, environmentally friendly, and particularly suitable for complex biological samples.

PO(CH2CH2CF3)3: an organic ultraviolet nonlinear optical material without any anionic group.

Researchers have focused on inorganic compounds to design deep ultraviolet (UV) nonlinear optical (NLO) materials according to anionic group theory, such as CO3 2-, NO3 -, SO4 2- and PO4 3- anions. Here we provide a new route to design an UV NLO material using a pure organic compound without any anions. Compound PO(CH2CH2CF3)31, an UV NLO material, has light transmittance up to 83% in the UV spectral region which is larger than most inorganic UV NLO materials. It also displays a wide transparent band, a SHG response of 0.30 × KH2PO4, and a cut-off edge below 200 nm. It displays ladder-like nonlinear optical properties weakened by 1.4 times at around T c, making compound 1 a potential temperature-controlled UV NLO material. Theoretical analyses reveal that the nonlinear optical properties are primarily due to O-2p, P-2p and F-2p.

A Novel Mouse Model Harboring Hepatitis B Virus Covalently Closed Circular DNA.

BACKGROUND AND AIMS: The persistence of viral covalently closed circular DNA (cccDNA) is the major obstacle for antiviral treatment against hepatitis B virus (HBV). Basic and translational studies are largely hampered due to the lack of feasible small animal models to support HBV cccDNA formation. The aim of this study is to establish a novel mouse model harboring cccDNA. METHODS: An adeno-associated virus (AAV) vector carrying a replication-deficient HBV1.04-fold genome (AAV-HBV1.04) was constructed. The linear HBV genome starts from nucleotide 403 and ends at 538, which results in the splitting of HBV surface and polymerase genes. Different HBV replication markers were evaluated for AAV-HBV1.04 plasmid-transfected cells, the AAV-HBV1.04 viral vector-transduced cells, and mice injected with the AAV-HBV1.04 viral vector. RESULTS: Compared with the previously reported AAV-HBV1.2 construct, direct transfection of AAV-HBV1.04 plasmid failed to produce hepatitis B surface antigen and progeny virus. Interestingly, AAV-HBV1.04 viral vector transduction could result in the formation of cccDNA and the production of all HBV replication markers in vitro and in vivo. The formation of cccDNA could be blocked by ATR (ataxia-telangiectasia and Rad3-related protein) inhibitors but not HBV reverse transcription inhibitor or capsid inhibitors. The AAV-HBV1.04 mouse supported long-term HBV replication and responded to antiviral treatments. CONCLUSIONS: This AAV-HBV1.04 mouse model can support HBV cccDNA formation through ATR-mediated DNA damage response. The de novo formed cccDNA but not the parental AAV vector can lead to the production of hepatitis B surface antigen and HBV progeny. This model will provide a unique platform for studying HBV cccDNA and developing novel antivirals against HBV infection.

G-quadruplexes sense natural porphyrin metabolites for regulation of gene transcription and chromatin landscapes.

BACKGROUND: G-quadruplexes (G4s) are unique noncanonical nucleic acid secondary structures, which have been proposed to physically interact with transcription factors and chromatin remodelers to regulate cell type-specific transcriptome and shape chromatin landscapes. RESULTS: Based on the direct interaction between G4 and natural porphyrins, we establish genome-wide approaches to profile where the iron-liganded porphyrin hemin can bind in the chromatin. Hemin promotes genome-wide G4 formation, impairs transcription initiation, and alters chromatin landscapes, including decreased H3K27ac and H3K4me3 modifications at promoters. Interestingly, G4 status is not involved in the canonical hemin-BACH1-NRF2-mediated enhancer activation process, highlighting an unprecedented G4-dependent mechanism for metabolic regulation of transcription. Furthermore, hemin treatment induces specific gene expression profiles in hepatocytes, underscoring the in vivo potential for metabolic control of gene transcription by porphyrins. CONCLUSIONS: These studies demonstrate that G4 functions as a sensor for natural porphyrin metabolites in cells, revealing a G4-dependent mechanism for metabolic regulation of gene transcription and chromatin landscapes, which will deepen our knowledge of G4 biology and the contribution of cellular metabolites to gene regulation.

[The spectroscopy analysis of intermolecular interaction between the template molecule and functional monomer before polymerization].

To prepare the non-covalent molecularly imprinted polymers (MIPs) with good adsorption properties,the degree of interaction is important factor between the template molecule and functional monomer before polymerization. The correlative research has been reported less. In the present paper, UV combined with infrared spectra was applied to study intermolecular interaction of the template molecule and functional monomer. andrographolide was used as the template molecule, acrylamide (AM) as the functional monomer in the three kinds of solvents, namely acetonitrile, tetrahydrofuran and ethyl acetate. The experimental results showed that the UV absorption peaks at 224 nm exhibited blue-shift of 5 nm, and the absorption peak increased for andrographolide and AM in acetonitrile solvent. In IR spectra, the O--H stretching vibration was also blue-shifted by nearly 8 cm(-1), while the N--H stretching vibration of blue shift was about 6 cm(-1). The data showed that the strong interaction of blue-shifted hydrogen bonds generated between the molecules of andrographolide and AM. And intermolecular interaction was very weak in other two solvents. It is obvious that the stronger the intermolecular interaction, the greater the spectroscopy changes, the better the selectivity of identification points, and thus the better the adsorption properties of MIPs are.

Descriptive, Retrospective Study of the Clinical Characteristics of Asymptomatic COVID-19 Patients.

Since the outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China, it has rapidly spread around the world. Persons with asymptomatic disease exhibit viral shedding, resulting in transmission, which presents disease control challenges. However, the clinical characteristics of these asymptomatic individuals remain elusive. We collected samples of 25 asymptomatic and 27 symptomatic COVID-19 patients. Viral titers of throat swabs were determined by quantitative reverse transcription-PCR (qRT-PCR). COVID-19 IgG and IgM were examined. Complete blood counts were determined, and serum biochemistry panels were performed. Cytokines, including gamma interferon (IFN-γ), tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2), IL-4, IL-6, and IL-10 were evaluated. T cell, B cell, and NK cell counts were measured using flow cytometry. Although similar viral loads were detected, asymptomatic patients had significantly faster virus turnover than symptomatic patients. Additionally, asymptomatic patients had higher counts of lymphocytes, T cells, B cells, and NK cells. While liver damage was observed in symptomatic patients, as indicated by elevated liver enzymes and decreased liver-synthesized proteins in the blood, asymptomatic patients showed normal liver measurements. Lactate dehydrogenase, a COVID-19 risk factor, was significantly lower in asymptomatic patients. These results suggest that asymptomatic COVID-19 patients had normal clinical indicators and faster viral clearance than symptomatic patients. Lymphocytes may play a role in their asymptomatic phenotype. Since asymptomatic patients may be a greater risk of virus transmission than symptomatic patients, public health interventions and a broader range of testing may be necessary for the control of COVID-19.IMPORTANCE Asymptomatic transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a potential problem for pandemic control through public health strategies. Our results demonstrate that asymptomatic COVID-19 patients have better outcomes than symptomatic patients. This may have been due to more active cellular immune responses and normal liver function. Since asymptomatic patients have no clinical symptoms which can easily prevent timely diagnosis and treatment, they may cause a greater risk of virus transmission than symptomatic patients, which poses a major challenge to infection control. Evidence suggests that nonpharmaceutical public health interventions, like social distancing and face mask ordinances, play important roles in the control of COVID-19. Looking forward, it may be necessary to proceed cautiously while reopening businesses in areas of epidemicity to prevent potential waves of COVID-19 in the future.

Three new Anthraquinones, one new Benzochromene and one new Furfural glycoside from Lasianthus acuminatissimus.

Three new anthraquinones, lasianthurin B (1), C (2), lasianthuoside D (3), a new benzochromene, lasianthurin D (4), and a new furfural glycoside, lasianthuoside E (5), together with one known compound 4- hydroxymethyl-2-furaldehyde (6) were isolated from an alcohol extract of the root of Lasianthus acuminatissimus. Their structures were elucidated on the basis of extensive spectroscopic data analysis (including 1D, 2D NMR, X-ray, and MS experiments) and comparsion to literature data.

Effect of Carrier Lipophilicity and Preparation Method on the Properties of Andrographolide⁻Solid Dispersion.

Solid dispersion (SD) is a useful approach to improve the dissolution rate and bioavailability of poorly water-soluble drugs. This work investigated the effects of carrier material lipophilicity and preparation method on the properties of andrographolide (AG)⁻SD. The SDs of AG and the carrier materials, polyethylene glycol (PEG) and PEG grafted with carbon chains of different length (grafted PEG), have been prepared by spray-drying and vacuum-drying methods. In AG⁻SDs prepared by the different preparation methods with the same polymer as carrier material, the intermolecular interaction, 5% weight-loss temperature, the melting temperature (Tm), surface morphology, crystallinity, and dissolution behavior have significant differences. In the AG⁻SDs prepared by the same spray-drying method with different grafted PEG as carrier material, Tm, surface morphology, crystallinity, and dissolution behavior had little difference. In the AG⁻SDs prepared by the same vacuum-drying method with different grafted PEG as carrier material, the crystallinity and Tm decreased, and the dissolution rate of AG increased with the increase of grafted PEG lipophilicity. The preparation method has an important effect on the properties of SD. The increase of carrier material lipophilicity is beneficial to the thermal stability of SD, the decrease of crystallinity and the increase of dissolution rate of a poorly water-soluble drug in the SD.

Randomized double-blind multicentre placebo-controlled clinical trial of the clonidine adhesive patch for the treatment of tic disorders.

OBJECTIVE: The aim of the present study was to evaluate the therapeutic effectiveness and safety of the clonidine adhesive patch in treating tic disorders. METHOD: A total of 437 patients, who met Chinese Classification of Mental Disorders-third edition diagnostic criteria for transient tic disorder (5%), chronic motor or vocal tic disorder (40%) or Tourette disorder (55%), aged 6-18 years, were divided randomly into an active treatment group and a clinical control group. Participants in the active treatment group were treated with a clonidine adhesive patch and participants in the clinical control group with a placebo adhesive patch for 4 weeks. The dosage of the clonidine adhesive patch was 1.0mg, 1.5mg or 2.0mg per week, depending on each participant's bodyweight. Participants whose Yale Global Tic Severity Scale (YGTSS) score decreased <30% and Clinical Global Impression score was > or =4 by the end of week 3 were withdrawn from the trial. RESULTS: After 4 weeks of treatment the active treatment group participants' YGTSS score was significantly lower than that of the clinical control group (F=4.63, p=0.03). Further, the active treatment group had a significantly better therapeutic response than the clinical control group (chi(2)=9.15, p=0.003). The response rate in the active treatment group was 68.85% compared to 46.85% in the clinical control group (chi(2)=16.98, p=0.0001). The rate of adverse events was low (active treatment group, 3.08%; clinical control group, 7.21%) and did not differ between the two groups. CONCLUSIONS: The clonidine adhesive patch is effective and safe for tic disorders.

[Evaluation of risk factors associated with cerebral palsy in children of Leshan Prefecture, Sichuan: a case control study on 308 cases].

OBJECTIVE: To evaluate the risk factors associated with pathogenesis of cerebral palsy (CP) in young children. METHODS: A cross-sectional survey on the prevalence of CP was conducted in young children aged one to six years in Leshan area, Sichuan Province. Cluster sampling and a 1:2 case-control design were used to investigate the risk factors for pathogenesis of CP. RESULTS: Totally, 148,723 children were surveyed, in which 308 (2.07 per thousand ) were diagnosed as CP. Low birth weight, twins and premature birth were associated with significantly increased prevalence of CP, 16.32, 4.16 and 22.21 times as that in normal birth weight, single birth and full-term birth, respectively. Simple factor analysis showed varied factors involved in pathogenesis of CP. The multivariate analysis revealed that delivery at home, low Apgar score in five minutes, illness during the first month of life, maternal "cold" with fever in their early gestation, low protein (meat and egg) intake during pregnancy and lower education level of mother were risk factors for CP. CONCLUSIONS: Prevalence and clinical features of CP in Leshan was comparable to those in the developed countries. Relevant risk factors could be seen primarily in gestational and perinatal periods, which might involve in mothers, children, environment and heredity, etc. To attach more importance in gestational and perinatal care for mothers and babies will be crucial measures to reduce occurrence of CP in young children.

[A multicenter controlled study on aripiprazole treatment for children with Tourette syndrome in China].

OBJECTIVE: To evaluate the efficacy and safety of aripiprazole in the treatment of children with Tourette syndrome. METHOD: A prospective, multi-center, controlled clinical trial was conducted in 195 children aged 5-17 years with Tourette syndrome. The patients were assigned to two groups: aripiprazole group (n=98) and tiapride group (n=97), with the treatment dosage of 5-25 mg/d and 100-500 mg/d, respectively. After 12 weeks treatment, the clinical efficacy was assessed by the Yale Global Tic Severity Scale (YGTSS) score, and adverse reactions were observed by side effects symptoms scale, blood biochemical indexes, and electrocardiography. RESULT: Significant pre- and post-treatment differences were ascertained for motor tic, phonic tic, function damage and total scores of YGTSS in the both groups from the second week of treatment (P<0.0001). Compared with the tiapride group, the aripiprazole group showed a more significantly decreased function damage score of YGTSS by the second week of treatment (P<0.05). After 12 weeks treatment, total scores of YGTSS in the aripiprazole group decreased from 53.74±15.71 at baseline to 24.36±16.38, while in the tiapride group from 51.66±13.63 to 23.26±15.31. The mean reduction scores of YGTSS were 29.38 in the aripiprazole group and 28.40 in the tiapride group at the end of treatment, and the clinical response rates were 60.21% and 63.92%, respectively. There were no significant differences between the 2 groups (P>0.05). The incidence of adverse reactions was similar in the aripiprazole and tiapride groups, with 29.6% and 27.8% respectively. There were no significant differences in the incidence of adverse reactions between aripiprazole and tiapride groups and no severe adverse events were found in either group. CONCLUSION: The results showed that aripiprazole showed similar therapeutic effect to tiapride in treatment of children with Tourette syndrome. Aripiprazole was safe and well tolerated in Chinese population, and can be considered as a new valid option for the treatment of tic disorders.