Development of Novel Antiviral Therapies for Hepatitis C Virus

Over 170 million people worldwide are infected with hepatitis C virus (HCV), a major cause of liver diseases. Current interferon-based therapy is of limited efficacy and has significant side effects and more effective and better tolerated therapies are urgently needed. HCV is a positive, single-stranded RNA virus with a 9.6 kb genome that encodes ten viral proteins. Among them, the NS3 protease and the NS5B polymerase are essential for viral replication and have been the main focus of drug discovery efforts. Aided by structure-based drug design, potent and specific inhibitors of NS3 and NS5B have been identified, some of which are in late stage clinical trials and may significantly improve current HCV treatment. Inhibitors of other viral targets such as NS5A are also being pursued. However, HCV is an RNA virus characterized by high replication and mutation rates and consequently, resistance emerges quickly in patients treated with specific antivirals as monotherapy. A complementary approach is to target host factors such as cyclophilins that are also essential for viral replication and may present a higher genetic barrier to resistance. Combinations of these inhibitors of different mechanism are likely to become the essential components of future HCV therapies in order to maximize antiviral efficacy and prevent the emergence of resistance.

Inhibiting WNT secretion reduces high bone mass caused by Sost loss-of-function or gain-of-function mutations in Lrp5

Proper regulation of Wnt signaling is critical for normal bone development and homeostasis.Mutations in several Wnt signaling components,which increase the activity of the pathway in the skeleton,cause high bone mass in human subjects and mouse models.Increased bone mass is often accompanied by severe headaches from increased intracranial pressure,which can lead to fatality and loss of vision or hearing due to the entrapment of cranial nerves.In addition,progressive forehead bossing and mandibular overgrowth occur in almost all subjects.Treatments that would provide symptomatic relief in these subjects are limited.Porcupine-mediated palmitoylation is necessary for Wnt secretion and binding to the frizzled receptor.Chemical inhibition of porcupine is a highly selective method of Wnt signaling inhibition.We treated three different mouse models of high bone mass caused by aberrant Wnt signaling,including homozygosity for loss-of-function in Sost,which models sclerosteosis,and two strains of mice carrying different point mutations in Lrp5(equivalent to human G171V and A214V),at 3 months of age with porcupine inhibitors for 5–6 weeks.Treatment significantly reduced both trabecular and cortical bone mass in all three models.This demonstrates that porcupine inhibition is potentially therapeutic for symptomatic relief in subjects who suffer from these disorders and further establishes that the continued production of Wnts is necessary for sustaining high bone mass in these models.

Dental and periodontal phenotype in sclerostin knockout mice

Sclerostin is a Wnt signalling antagonist that controls bone metabolism. Sclerostin is expressed by osteocytes and cementocytes; however, its role in the formation of dental structures remains unclear. Here, we analysed the mandibles of sclerostin knockout mice to determine the influence of sclerostin on dental structures and dimensions using histomorphometry and micro-computed tomography （μCT） imaging, μCT and histomorphometric analyses were performed on the first lower molar and its surrounding structures in mice lacking a functional sclerostin gene and in wild-type controls, pCT on six animals in each group revealed that the dimension of the basal bone as well as the coronal and apical part of alveolar part increased in the sclerostin knockout mice. No significant differences were observed for the tooth and pulp chamber volume. Descriptive histomorphometric analyses of four wild-type and three sclerostin knockout mice demonstrated an increased width of the cementum and a concomitant moderate decrease in the periodontal space width. Taken together, these results suggest that the lack of sclerostin mainly alters the bone and cementum phenotypes rather than producing abnormalities in tooth structures such as dentin.

Frontier of therapeutic antibody discovery:The challenges and how to face them

Therapeutic monoclonal antibodies have become an important class of modern medicines.The established technologies for therapeutic antibody discovery such as humanization of mouse antibodies,phage display of human antibody libraries and transgenic animals harboring human IgG genes have been practiced successfully so far,and many incremental improvements are being made constantly.These methodologies are responsible for currently marketed therapeutic antibodies and for the biopharma industry pipeline which are concentrated on only a few dozen targets.A key challenge for wider application of biotherapeutic approaches is the paucity of truly validated targets for biotherapeutic intervention.The efforts to expand the target space include taking the pathway approach to study the disease correlation.Since many new targets are multi-spanning and multimeric membrane proteins there is a need to develop more effective methods to generate antibodies against these difficult targets.The pharmaceutical properties of therapeutic antibodies are an active area for study concentrating on biophysical characteristics such as thermal stability and aggregation propensity.The immunogenicity of biotherapeutics in humans is a very complex issue and there are no truly predictive animal models to rely on.The in silico and T-cell response approaches identify the potential for immunogenicity;however,one needs contingency plans for emergence of antiproduct antibody response for clinical trials.

MRI对高致敏性小鼠的抗原诱导的肺炎的评价

目的探讨MR质子成像无创性检查抗原诱导的呼吸道炎症小鼠模型血管外及腔内液体的可行性。材料及方法巴塞尔兽医权威机构批准了这项试验。

Fabricating 3-dimensional human brown adipose microtissues for transplantation studies

Transplanting cell cultured brown adipocytes(BAs)represents a promising approach to prevent and treat obesity(OB)and its associated metabolic disorders,including type 2 diabetes mellitus(T2DM).However,transplanted BAs have a very low survival rate in vivo.The enzymatic dissociation during the harvest of fully differentiated BAs also loses significant cells.There is a critical need for novel methods that can avoid cell death during cell preparation,transplantation,and in vivo.Here,we reported that preparing BAs as injectable microtissues could overcome the problem.We found that 3D culture promoted BA differentiation and UCP-1 expression,and the optimal initial cell aggregate size was 100μm.The microtissues could be produced at large scales via 3D suspension assisted with a PEG hydrogel and could be cryopreserved.Fabricated microtissues could survive in vivo for long term.They alleviated body weight and fat gain and improved glucose tolerance and insulin sensitivity in high-fat diet(HFD)-induced OB and T2DM mice.Transplanted microtissues impacted multiple organs,secreted protein factors,and influenced the secretion of endogenous adipokines.To our best knowledge,this is the first report on fabricating human BA microtissues and showing their safety and efficacy in T2DM mice.The proposal of transplanting fabricated BA microtissues,the microtissue fabrication method,and the demonstration of efficacy in T2DM mice are all new.Our results show that engineered 3D human BA microtissues have considerable advantages in product scalability,storage,purity,safety,dosage,survival,and efficacy.

Nrf2-mediated antioxidant and detoxifying enzyme induction by a combination of curcumin and sulforaphaneNrf2-mediated antioxidant and detoxifying enzyme induction by a combination of curcumin and sulforaphane

The dietary phytochemicals curcumin(CUR) and sulforaphane(SFN) have shown remarkable cancer chemopreventive effects in many model systems. This study was designed to investigate the induction of Nrf2-mediated antioxidant enzymes by combining doses of CUR and SFN and the effect of their combination on the Nrf2-ARE(antioxidant response element) response in Hep G2-C8 cells. We hypothesized that the combination of the polyphenol CUR and the isothiocyanate SFN could enhance the induction of AREs and Nrf2-target enzymes. Hep G2-C8 cells were treated with a combination of low doses of CUR, SFN or both. The induction of Nrf2-mediated antioxidant and phase II detoxifying enzymes–heme oxygenase-1(HO-1) and UDP-glucuronosyltransferase-1A(UGT1A)–was measured by real-time RT-PCR and western blotting. ARE-luciferase activity was also quantified. Low doses of CUR(10 μM) and SFN(12.5 μM) significantly induced the expression of HO-1 and UGT1A1 proteins. Through the use of chemical inhibitors of mR NA and protein synthesis, the combination of CUR and SFN was shown to affect the transcriptional regulation of both HO-1 and UGT1A1. Additionally, the combination of CUR and SFN synergistically induced the expression of Nrf2- and ARE-luciferase activity in Hep G2-C8 cells. Thus, CUR and SFN at low concentrations augment therapeutic effects in Hep G2-C8 cells. The enhanced ARE-luciferase activity of combined CUR and SFN treatment could partly explain the significant induction of the Nrf2-target enzymes HO-1 and UGT1A1. Taken together, our results suggest that combining low doses of CUR and SNF could be a promising strategy for cancer chemoprevention in humans.

VprBP mitigates TGF-β and Activin signaling by promoting Smurf1-mediated type Ⅰ receptor degradation

The transforming growth factor-β(TGF-β)family controls embryogenesis,stem cell differentiation,and tissue homeostasis.However,how post-translation modifications contribute to fine-tuning of TGF-βfamily signaling responses is not well understood.Inhibitory(I)-Smads can antagonize TGF-β/Smad signaling by recruiting Smurf E3 ubiquitin ligases to target the active TGF-βreceptor for proteasomal degradation.A proteomic interaction screen identified Vpr binding protein(VprBP)as novel binding partner of Smad7.Mis-expression studies revealed that VprBP negatively controls Smad2 phosphorylation,Smad2–Smad4 interaction,as well as TGF-βtarget gene expression.VprBP was found to promote Smad7–Smurf1–TβRI complex formation and induce proteasomal degradation of TGF-βtype I receptor(TβRI).Moreover,VprBP appears to stabilize Smurf1 by suppressing Smurf1 poly-ubiquitination.In multiple adult and mouse embryonic stem cells,depletion of VprBP promotes TGF-βor Activin-induced responses.In the mouse embryo VprBP expression negatively correlates with mesoderm marker expression,and VprBP attenuated mesoderm induction during zebrafish embryogenesis.Our findings thereby uncover a novel regulatory mechanism by which Smurf1 controls the TGF-βand Activin cascade and identify VprBP as a critical determinant of embryonic mesoderm induction.

Secukinumab provided significant and sustained improvement in the signs and symptoms of ankylosing spondylitis:results from the 52-week,PhaseⅢChina-centric study,MEASURE 5

Background:Secukinumab demonstrated sustained efficacy in patients with ankylosing spondylitis(AS)through 5 years in pivotal Phase III studies.Here,we present efficacy and safety results(52-week)of secukinumab in patients with AS from the MEASURE 5 study.Methods:MEASURE 5 was a 52-week,Phase III,China-centric study.Eligible patients were randomly assigned(2:1)to receive subcutaneous secukinumab 150 mg or placebo weekly for the first five doses and then once every 4 weeks(q4w).All placebo patients switched to secukinumab 150 mg q4w starting at Week 16.Primary endpoint was Assessments of SpondyloArthritis international Society(ASAS)20 at Week 16.Randomization was stratified by region(China vs.non-China).Results:Of 458 patients(secukinumab 150 mg,N=305;placebo,N=153)randomized,327(71.4%)were from China and 131(28.6%)were not from China.Of these,97.7%and 97.4%patients completed Week 16 and 91.1%and 95.3%(placebo-secukinumab)patients completed Week 52 of treatment.The primary endpoint was met;secukinumab significantly improved ASAS20 response at Week 16 vs.placebo(58.4%vs.36.6%;P<0.0001);corresponding rate in the Chinese population was 56.0%vs.38.5%(P<0.01).All secondary efficacy endpoints significantly improved with secukinumab 150 mg in the overall population at Week 16;responses were maintained with a trend toward increased efficacy from Week 16 to 52.No new or unexpected safety signals were reported up to Week 52.Conclusions:Secukinumab 150 mg demonstrated rapid and significant improvement in signs and symptoms of AS.Secukinumab was well tolerated and the safety profile was consistent with previous reports.Efficacy and safety results were comparable between the overall and Chinese populations.

Ways and waves of MALT1 paracaspase activation

Mucosa-associated lymphoid tissue lymphoma translocation protein 1(MALT1),also known as paracaspase 1,is a ubiquitous protease with homology to caspases.1 The function of MALT1 is best understood in immune cells,in particular lymphocytes,in which MALT1 controls signaling downstream of antigen receptors,for example,nuclear-factor-kappa-B(NF-κB)and mitogen-activated protein kinase pathways.Activation of MALT1 paracaspase activity has been shown to require the assembly of a tripartite signaling complex termed CBM(CARD11/BCL10/MALT1),which is formed following the phosphorylation and conformational change of caspase recruitment domain 11(CARD11)that is induced by antigen-receptor stimulation.

Cancer Res:HDAC抑制剂可促进单抗药物对HER2阳性肿瘤的治疗效果

最近来自澳大利亚墨尔本的研究人员发现组蛋白去乙酰化酶抑制剂可以发动宿主免疫作为其抗肿瘤效应的一个基础。该研究为增强一些肿瘤免疫治疗药物的杀伤作用提供了新的方向。在这项发表在国际学术期刊Cancer Research上的研究中，研究人员发现组蛋白去乙酰化酶抑制剂panobinostat可以通过宿主免疫增强trastuzumab这种单抗治疗药物的抗肿瘤效果。