Selective lignin arylation for biomass fractionation and benign bisphenols.

Lignocellulose is mainly composed of hydrophobic lignin and hydrophilic polysaccharide polymers, contributing to an indispensable carbon resource for green biorefineries1,2. When chemically treated, lignin is compromised owing to detrimental intra- and intermolecular crosslinking that hampers downstream process3,4. The current valorization paradigms aim to avoid the formation of new C-C bonds, referred to as condensation, by blocking or stabilizing the vulnerable moieties of lignin5-7. Although there have been efforts to enhance biomass utilization through the incorporation of phenolic additives8,9, exploiting lignin's proclivity towards condensation remains unproven for valorizing both lignin and carbohydrates to high-value products. Here we leverage the proclivity by directing the C-C bond formation in a catalytic arylation pathway using lignin-derived phenols with high nucleophilicity. The selectively condensed lignin, isolated in near-quantitative yields while preserving its prominent cleavable ß-ether units, can be unlocked in a tandem catalytic process involving aryl migration and transfer hydrogenation. Lignin in wood is thereby converted to benign bisphenols (34-48 wt%) that represent performance-advantaged replacements for their fossil-based counterparts. Delignified pulp from cellulose and xylose from xylan are co-produced for textile fibres and renewable chemicals. This condensation-driven strategy represents a key advancement complementary to other promising monophenol-oriented approaches targeting valuable platform chemicals and materials, thereby contributing to holistic biomass valorization.

Mast cells contribute to Enterovirus 71 infection-induced pulmonary edema in neonatal mice.

Enterovirus (EV) 71 infection has been widely acknowledged as the leading cause of severe hand, foot and mouth disease (HFMD), which may rapidly lead to fatal pulmonary edema. In this study, we established a mouse model for EV71 infection exhibiting high incidence of severe symptoms with pulmonary edema. Mast cells (MCs) accumulation, activation and allergic inflammation were found in the brains, lungs and skeletal muscle of mice after EV71 infection, especially in the lungs of mice. Levels of histamine, platelet-activating factor (PAF), interleukin (IL)-4, IL-5, IL-13, tumor necrosis factor-α (TNF-α), nitric oxide (NO), endocrine gland-derived vascular endothelial growth factor (EG-VEGF) and noradrenaline (NA) were increased in EV71-infected lungs. In addition, EV71 infection reduced the number of pulmonary T cells, dendritic cells (DCs) and monocytes, and increased the number of lung eosinophils, Tregs and MCs. MCs number and tryptase expression in target organs or tissues posed a trend towards an increase from control to severe mice. There were positive correlations between MCs number in the brains (r = 0.701, P = 0.003), lungs (r = 0.802, P < 0.0001), skeletal muscles (r = 0.737, P = 0.001) and mean clinical score. Thus, our results suggested that MCs contributed to the pulmonary edema during EV71 infection.

Pulmonary edema following central nervous system lesions induced by a non- mouse-adapted EV71 strain in neonatal BALB/c mice.

BACKGROUND: Enterovirus (EV) infection has been a serious health issue in Asia-Pacific region. It has been indicated that the occurrence of fatal hand foot and mouth disease (HFMD) cases following EV71 infection is mainly attributed to pulmonary edema. However, the development of pulmonary disorders after EV71 infection remains largely unknown. To establish an EV71-infected animal model and further explore the underlying association of central nervous system (CNS) invasion with pulmonary edema, we isolated a clinical source EV71 strain (ZZ1350) from a severe case in Henan Province. METHODS: We evaluated the cytotoxicity of ZZ1350 strain and the susceptibility in 3-day-old BALB/c mice with intraperitoneal, intracerebral and intramuscular inoculation. Various histopathological and immunohistochemical techniques were applied to determine the target organs or tissue damage after infection. Correlation analysis was used to identify the relationship between CNS injury and pulmonary disorders. RESULTS: Our experimental results suggested that ZZ1350 (C4 subtype) had high cytotoxicity against African green monkey kidney (Vero) cells and human rhabdomyosarcoma (RD) cells and neonatal BALB/c mice were highly susceptible to the infection with ZZ1350 through three different inoculation routes (2 × 106 pfu/mouse) exhibiting severe neurological and respiratory symptoms that were similar to clinical observation. Viral replication was found in brain, spinal cord, skeletal muscle, lung, spleen, liver, heart of infected mice and these sections also showed histopathological changes. We found that brain histology score was positive correlated with lung histology score in total experimental mice and mice under the three inoculation routes (P < 0.05). At the same time, there were positive correlations between spinal cord score and lung score in total experimental mice and mice with intracerebral inoculation (P < 0.05). CONCLUSIONS: ZZ1350 strain is effective to establish animal model of EV71 infection with severe neurological and respiratory symptoms. The development of pulmonary disorders after EV71 infection is associated with severity of CNS damage.

Use of asymmetric multilayer polylactide nanofiber mats in controlled release of drugs and prevention of liver cancer recurrence after surgery in mice.

Local tumor recurrence remains a major clinical problem following surgical treatment for most cancers such as hepatocellular carcinoma (HCC). An implantable local drug delivery system may be suitable for addressing this unmet clinical need. In this study, asymmetric multilayer polylactide nanofiber (AMPN) mats were prepared and a one-sided and prolonged release profile of hydrophilic dye or oxaliplatin was observed after they were sandwiched between two liver lobes in mice. Covering the surgery site by drug-loaded AMPN mat after tumor resection, in both subcutaneous and orthotopic HCC model in mice, the recurrence of HCC was significantly retarded and the survival time of mice was markedly prolonged. In conclusion, post-surgical therapy at tumor resection margins by drug-loaded AMPN mats may represent a suitable application of nanofiber-based local chemotherapy. FROM THE CLINICAL EDITOR: After cancer surgery, local recurrence remains a significant problem. In this study, the authors designed asymmetric multilayer PLA nanofiber (AMPN) mats and loaded them with anti-tumor drugs. Both in-vitro and in-vivo experiments showed good efficacy in preventing tumor recurrence. This novel product may point a way to the future and improve survival of cancer patients.

Low-Temperature Printed Hierarchically Porous Induced-Biomineralization Polyaryletherketone Scaffold for Bone Tissue Engineering.

Polyetheretherketone (PEEK) as a popular orthopaedic implant is usually fabricated into a hierarchically porous structure for improving osteogenic activity. However, the applications are limited due to the excessively high processing temperature and uncontrollably tedious modification routes. Here, an amorphous polyaryletherketone with carboxyl groups (PAEK-COOH) is synthesized and fabricated to the hierarchically controllable porous scaffolds via a low-temperature 3D-printing process. The prepared PAEK-COOH scaffolds present controllable porous structures ranging from nano- to micro-scale, and their mechanical strengths are comparable to that of trabecular bone. More importantly, the in vitro experiments show that the nanoporous surface is conducive to promoting cellular adhesion, and carboxyl groups can induce hydroxyapatite mineralization via electrostatic interaction. The in vivo experiments demonstrate that the PAEK-COOH scaffolds offer much better osseointegration without additional active ingredients, compared to that of PEEK. Therefore, this work will not only develop a promising candidate for bone tissue engineering, but provide a viable method to design PAEK biomaterials.

Bio-effects of bio-based and fossil-based microplastics: Case study with lettuce-soil system.

Bio-based plastics have been developed as alternative materials to solve the energy crisis brought by plastic production, but their impacts on soil ecosystems (e.g. plant and microorganisms) remain largely unknown. Here, we conducted study on the impacts of polyethylene 2,5-furan-dicarboxylate (PEF), a new bio-based plastic, on the plant-soil ecosystem, with comparison of fossil-based plastic polyethylene terephthalate (PET). Our investigation showed that, after 21 days exposure to microplastics (MPs) at doses of 0.5%, 1% and 2%, both PEF and PET MPs inhibited the growth of lettuce, where chlorophyll was found to be the most sensitive index. According to the comprehensive stress resistance indicators, PET MPs showed more severe phytotoxicity than PEF MPs. Although both PEF and PET MPs could inhibit soil enzyme activities, PET MPs exhibited significantly reduction on the diversity of rhizosphere soil bacterial community and changed the relative abundance of dominant species. Our study gave insights into the effects of PEF and PET MPs on the plant-soil system, where bio-based PEF MPs showed more friendly interaction with plant and soil than fossil-based PET MPs. Our results provided scientific data for risk assessment and useful information for the prospective application of bio-based plastics.

Neonatal Murine Model of Coxsackievirus A2 Infection for the Evaluation of Antiviral Therapeutics and Vaccination.

Coxsackievirus (CV) A2 has emerged as an important etiological agent in the pathogen spectrum of hand, foot, and mouth disease (HFMD). The symptoms of CVA2 infections are generally mild, but worsen rapidly in some people, posing a serious threat to children's health. However, compared with enterovirus 71 detected frequently in fatal cases, limited attention has been paid to CVA2 infections because of its benign clinical course. In the present study, we identified three CVA2 strains from HFMD infections and used the cell-adapted CVA2 strain HN202009 to inoculate 5-day-old BALB/c mice intramuscularly. These mice developed remarkably neurological symptoms such as ataxia, hind-limb paralysis, and death. Histopathological determination showed neuronophagia, pulmonary hemorrhage, myofiberlysis and viral myocarditis. Viral replication was detected in multiple organs and tissues, and CVA2 exhibited strong tropism to muscle tissue. The severity of illness was associated with abnormally high levels of inflammatory cytokines, including interleukin (IL)-6, IL-10, tumor necrosis factor α, and monocyte chemotactic protein 1, although the blockade of these proinflammatory cytokines had no obvious protection. We also tested whether an experimental formaldehyde-inactivated CVA2 vaccine could induce protective immune response in adult mice. The CVA2 antisera from the vaccinated mice were effective against CVA2 infection. Moreover, the inactivated CVA2 vaccine could successfully generate immune protection in neonatal mice. Our results indicated that the neonatal mouse model could be a useful tool to study CVA2 infection and to develop CVA2 vaccines.

Pathogenesis Study of Enterovirus 71 Using a Novel Human SCARB2 Knock-In Mouse Model.

Enterovirus 71 (EV71) can cause a severe hand-foot-mouth disease in children. However, the precise mechanism of EV71-associated disease, particularly the neuropathogenesis and pulmonary disorder, is still not fully understood because no suitable animal models are available. The human scavenger receptor class B, member 2 (hSCARB2), is a cellular receptor for EV71. Here, we generated a novel knock-in (KI) mouse model using the CRISPR/Cas9 system to insert the hSCARB2 gene into the mouse Rosa26 locus to study the pathogenesis of EV71. The hSCARB2 KI mice infected with clinical isolates of EV71 showed neurological symptoms, such as ataxia, paralysis, and death. Viral replication was detected in mainly astrocytes and a limited number of neurons and microglia, accompanied by gliosis. Vascular leakage and alveoli filled with erythrocytes were detected, suggesting that edema and hemorrhage, which are observed in human patients, also occurred in EV71-infected KI mice. In addition, proinflammatory cytokines and chemokines were significantly increased in the serum of infected KI mice. These pathological features of the KI mice after infection resembled those of EV71 encephalomyelitis in humans. Therefore, our KI mouse model is suitable to study the pathogenesis of EV71 and is of great significance for development of antiviral drugs and vaccines to treat or prevent EV71 infection.IMPORTANCE Enterovirus 71 (EV71) is associated with severe hand-foot-mouth disease. Recently, outbreaks of EV71 infection with high mortality have been reported in the Asia-Pacific region, posing a great challenge for global public health. To date, the precise mechanism of EV71-induced disease, particularly the neuropathogenesis and respiratory disorders, is still not fully understood because no suitable animal models are available. Human scavenger receptor class B, member 2 (hSCARB2), has been identified as a cellular receptor for EV71. Here, we introduce a novel CRISPR/Cas9-mediated hSCARB2 knock-in (KI) mouse model for the study of EV71 pathogenesis, which is of great significance for the development of antiviral drugs and vaccines.

Preparation of Amorphous Poly(aryl ether nitrile ketone) and Its Composites with Nano Hydroxyapatite for 3D Artificial Bone Printing.

PEEK had been used to fabricate artificial bones by 3D printing widely, but it expressed unsatisfactory interlayer performance of 3D printing and weak compatibility with nano hydroxyapatite(nHA) due to the limits of molecular structures. Here an amorphous poly(aryl ether ketone) for 3D bone printing, PEK-CN, was designed and synthesized via nucleophilic substitution from 4,4'-difluorobenzophenone, phenolphthalein and 2,6-dichlorobenzonitrile, which possessed much stronger interlayer strength due to van der Waals force between polar groups(-CNs). Specifically, the stronger interlayer strength resulted in lower porosity(3% with 100% infill rate) and more comparable mechanical properties(the maximum tensile strength was ∼110 MPa) to cortical bone. Importantly, PEK-CN had passed in vitro cytotoxicity testing and samples of human mandible and maxillary bones based on PEK-CN were printed by fused deposition modeling(FDM) successfully. Moreover, PEK-CN/nHA composites were obtained to enhance bioactivity of resin, and PEK-CN without limits of crystal lattices expressed excellent compatibility with nano hydroxyapatite. Our work provided a high performance resin for 3D bone printing, which would bring better solutions for artificial bone materials.

Identification of immune and metabolic predictors of severe hand-foot-mouth disease.

Hand, foot and mouth disease (HFMD) is an infectious disease that affects mostly children. The children with HFMD also have other immune and metabolic disorders. However, the association of these disorders with the severity of HFMD has not yet been determined. In this study, we used a case-control study design to examine the correlation of immune and metabolic disorders with HFMD development in children. 406 mild and severe patients were recruited and divided into different subgroups based on the number of days from the initial onset time to hospitalization (1, 2, 3, 4, and ≥5 days). Logistic regression model was used to define the predictors of severe HFMD. We found that the patients from rural area (OR = 1.76, 95% CI [1.19~2.63], P = 0.005) or with body temperature of >39°C (OR = 2.14, 95% CI [1.12~4.12], P = 0.022) exhibited higher risk for severe symptoms. In addition, the risk increased with the rise of body temperature by using a Chis-quare trend test (P = 0.01). We also found that a decreased number of eosinophils was an predictor of severe HFMD at 1, 2, 3,and 4 days post infection (dpi). Decreased levels of Na+, Cl-, and creatine kinase were also predictors at 1 and ≥5 dpi. On the other hand, elevated level of globulin was a predictor for severe HFMD at 4 dpi and ≥5 dpi, and the increased number of neutrophils or increased level of alkaline phosphatase posed risk for severe HFMD at 3 and ≥5 dpi. Our results suggested that rural living, hyperpyrexia, changes in the immune system that include the numbers of eosinophils and neutrophils and the levels of IgG and globulin, and metabolic alterations, such as the levels of alkaline phosphatase, Na+, Cl-, and creatine kinase in peripheral blood are predictors of severe HFMD.

Involvement of the renin-angiotensin system in the progression of severe hand-foot-and-mouth disease.

BACKGROUND: Hand-foot-and-mouth disease (HFMD) is generally considered as a mild exanthematous disease to infants and young children worldwide. HFMD cases are usually mild and self-limiting but for few cases leads to complicated severe clinical outcomes, and even death. Previous studies have indicated that serum Ang II levels in patients with H7N9 infection were related to the severity of infection. However, the mechanisms underlying the pathogenesis of severe HFMD remain unclear. This study was undertaken to clarify the role of the renin-angiotensin system (RAS) in the progression of severe HFMD. METHODS: In the present study, 162 children including HFMD patients and healthy controls were recruited. The data was analyzed by time-series fashion. Concentrations of angiotensin II (Ang II) and noradrenaline (NA) in serum of patients were measured with ELISA. We established a mouse model for enterovirus 71 (EV71) infection and determined concentrations of Ang II, NA in tissue lysates at 3, 5 and 7 days post infection (dpi). RESULTS: The concentrations of Ang II and NA in serum of the HFMD patients with mild or severe symptoms were significantly higher than that in healthy controls. Additionally, the concentrations of Ang II and NA in serum of severe cases were significantly higher than those mild cases and the increased concentrations of Ang II and NA showed the same time trend during the progression of HFMD in the severe cases. Furthermore, the concentrations of Ang II and NA in target organs of EV71-infected mice including brains, skeletal muscle, and lungs were increased with the progression of EV71 infection in mice. Histopathological alterations were observed in the brains, skeletal muscle and lungs of EV71-infected mice. CONCLUSION: Our study suggested that activation of the RAS is implicated in the pathogenesis of severe HFMD.

Characterization of Critical Functions of Long Non-Coding RNAs and mRNAs in Rhabdomyosarcoma Cells and Mouse Skeletal Muscle Infected by Enterovirus 71 Using RNA-Seq.

Enterovirus 71 (EV71) is the main pathogen of severe hand-foot-mouth disease (HFMD). Long non-coding RNAs (lncRNAs) are recognized as pivotal factors during the pathogenesis of viral infection. However, the critical functions of lncRNAs in EV71⁻host interactions have not been characterized. Here, for the first time, we performed global transcriptome analysis of lncRNA and mRNA expression profiles in EV71-infected human rhabdomyosarcoma (RD) cells and skeletal muscle of mice using second-generation sequencing. In our study, a total of 3801 novel lncRNAs were identified. In addition, 23 lncRNAs and 372 mRNAs exhibited remarkable differences in expression levels between infected and uninfected RD cells, while 104 lncRNAs and 2647 mRNAs were differentially expressed in infected skeletal muscle from neonatal mice. Comprehensive bioinformatics analysis included target gene prediction, lncRNA­mRNA co-expression network construction, as well as gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis mainly focused on differentially-expressed genes (DEGs). Our results suggest that lncRNAs may participate in EV71 infection-induced pathogenesis through regulating immune responses, protein binding, cellular component biogenesis and metabolism. The present study provides novel insights into the functions of lncRNAs and the possible pathogenic mechanism following EV71 infection.

Involvement of inducible nitric oxide synthase and mitochondrial dysfunction in the pathogenesis of enterovirus 71 infection.

Enterovirus71 (EV71) is recognized as the main causative agent of severe hand, foot and mouth disease (HFMD). However, the pathogenesis of EV71 infection has not been well characterized. Clinical evidence indicated that inducible nitric oxide synthase (iNOS) induction in the lung of HFMD patients contributes to the severe symptoms of pulmonary edema. In the present study, we recruited 142 subjects including HFMD patients and controls, and serum level of nitric oxide (NO) was determined. Next, cellular and animal model were used to further investigate the roles of iNOS and mitochondria damage during EV71 infection. Serum NO level in HFMD patients with mild or severe symptoms was higher than that in controls, and there was a trend towards an increase in the serum NO level of severe cases relative to mild cases. EV71 infection caused apoptosis and increased levels of NO, iNOS, superoxide dismutase (SOD) activity and malondialdehyde (MDA), and degraded mitochondrial membrane potential (ΔΨm) in vitro. Pathological alterations of mitochondrial morphology were observed in vitro and in vivo. Furthermore, the expression of iNOS levels in target organs including brain, spinal cord, skeletal muscle, lung and heart were increased with the progression of the pathogenesis of EV71 infection in mice. Taken together, iNOS and mitochondrial damage participate in the pathogenesis of EV71 infection.

Electrospinning of polymeric nanofibers for drug delivery applications.

Electrospinning has been recognized as a simple and versatile method for fabrication of polymer nanofibers. Various polymers that include synthetic, natural, and hybrid materials have been successfully electrospun into ultrafine fibers. The inherently high surface to volume ratio of electrospun fibers can enhance cell attachment, drug loading, and mass transfer properties. Drugs ranging from antibiotics and anticancer agents to proteins, DNA, RNA, living cells, and various growth factors have been incorporated into electrospun fibers. This article presents an overview of electrospinning techniques and their application in drug delivery.