SARS-CoV-2 Infection Depends on Cellular Heparan Sulfate and ACE2.

We show that SARS-CoV-2 spike protein interacts with both cellular heparan sulfate and angiotensin-converting enzyme 2 (ACE2) through its receptor-binding domain (RBD). Docking studies suggest a heparin/heparan sulfate-binding site adjacent to the ACE2-binding site. Both ACE2 and heparin can bind independently to spike protein in vitro, and a ternary complex can be generated using heparin as a scaffold. Electron micrographs of spike protein suggests that heparin enhances the open conformation of the RBD that binds ACE2. On cells, spike protein binding depends on both heparan sulfate and ACE2. Unfractionated heparin, non-anticoagulant heparin, heparin lyases, and lung heparan sulfate potently block spike protein binding and/or infection by pseudotyped virus and authentic SARS-CoV-2 virus. We suggest a model in which viral attachment and infection involves heparan sulfate-dependent enhancement of binding to ACE2. Manipulation of heparan sulfate or inhibition of viral adhesion by exogenous heparin presents new therapeutic opportunities.

Functional landscape of SARS-CoV-2 cellular restriction.

A deficient interferon (IFN) response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been implicated as a determinant of severe coronavirus disease 2019 (COVID-19). To identify the molecular effectors that govern IFN control of SARS-CoV-2 infection, we conducted a large-scale gain-of-function analysis that evaluated the impact of human IFN-stimulated genes (ISGs) on viral replication. A limited subset of ISGs were found to control viral infection, including endosomal factors inhibiting viral entry, RNA binding proteins suppressing viral RNA synthesis, and a highly enriched cluster of endoplasmic reticulum (ER)/Golgi-resident ISGs inhibiting viral assembly/egress. These included broad-acting antiviral ISGs and eight ISGs that specifically inhibited SARS-CoV-2 and SARS-CoV-1 replication. Among the broad-acting ISGs was BST2/tetherin, which impeded viral release and is antagonized by SARS-CoV-2 Orf7a protein. Overall, these data illuminate a set of ISGs that underlie innate immune control of SARS-CoV-2/SARS-CoV-1 infection, which will facilitate the understanding of host determinants that impact disease severity and offer potential therapeutic strategies for COVID-19.

Clofazimine broadly inhibits coronaviruses including SARS-CoV-2.

The COVID-19 pandemic is the third outbreak this century of a zoonotic disease caused by a coronavirus, following the emergence of severe acute respiratory syndrome (SARS) in 20031 and Middle East respiratory syndrome (MERS) in 20122. Treatment options for coronaviruses are limited. Here we show that clofazimine-an anti-leprosy drug with a favourable safety profile3-possesses inhibitory activity against several coronaviruses, and can antagonize the replication of SARS-CoV-2 and MERS-CoV in a range of in vitro systems. We found that this molecule, which has been approved by the US Food and Drug Administration, inhibits cell fusion mediated by the viral spike glycoprotein, as well as activity of the viral helicase. Prophylactic or therapeutic administration of clofazimine in a hamster model of SARS-CoV-2 pathogenesis led to reduced viral loads in the lung and viral shedding in faeces, and also alleviated the inflammation associated with viral infection. Combinations of clofazimine and remdesivir exhibited antiviral synergy in vitro and in vivo, and restricted viral shedding from the upper respiratory tract. Clofazimine, which is orally bioavailable and comparatively cheap to manufacture, is an attractive clinical candidate for the treatment of outpatients and-when combined with remdesivir-in therapy for hospitalized patients with COVID-19, particularly in contexts in which costs are an important factor or specialized medical facilities are limited. Our data provide evidence that clofazimine may have a role in the control of the current pandemic of COVID-19 and-possibly more importantly-in dealing with coronavirus diseases that may emerge in the future.

Discovery of SARS-CoV-2 antiviral drugs through large-scale compound repurposing.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019 has triggered an ongoing global pandemic of the severe pneumonia-like disease coronavirus disease 2019 (COVID-19)1. The development of a vaccine is likely to take at least 12-18 months, and the typical timeline for approval of a new antiviral therapeutic agent can exceed 10 years. Thus, repurposing of known drugs could substantially accelerate the deployment of new therapies for COVID-19. Here we profiled a library of drugs encompassing approximately 12,000 clinical-stage or Food and Drug Administration (FDA)-approved small molecules to identify candidate therapeutic drugs for COVID-19. We report the identification of 100 molecules that inhibit viral replication of SARS-CoV-2, including 21 drugs that exhibit dose-response relationships. Of these, thirteen were found to harbour effective concentrations commensurate with probable achievable therapeutic doses in patients, including the PIKfyve kinase inhibitor apilimod2-4 and the cysteine protease inhibitors MDL-28170, Z LVG CHN2, VBY-825 and ONO 5334. Notably, MDL-28170, ONO 5334 and apilimod were found to antagonize viral replication in human pneumocyte-like cells derived from induced pluripotent stem cells, and apilimod also demonstrated antiviral efficacy in a primary human lung explant model. Since most of the molecules identified in this study have already advanced into the clinic, their known pharmacological and human safety profiles will enable accelerated preclinical and clinical evaluation of these drugs for the treatment of COVID-19.

SARS-CoV-2 infects human brain organoids causing cell death and loss of synapses that can be rescued by treatment with Sofosbuvir.

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19), which was rapidly declared a pandemic by the World Health Organization (WHO). Early clinical symptomatology focused mainly on respiratory illnesses. However, a variety of neurological manifestations in both adults and newborns are now well-documented. To experimentally determine whether SARS-CoV-2 could replicate in and affect human brain cells, we infected iPSC-derived human brain organoids. Here, we show that SARS-CoV-2 can productively replicate and promote death of neural cells, including cortical neurons. This phenotype was accompanied by loss of excitatory synapses in neurons. Notably, we found that the U.S. Food and Drug Administration (FDA)-approved antiviral Sofosbuvir was able to inhibit SARS-CoV-2 replication and rescued these neuronal alterations in infected brain organoids. Given the urgent need for readily available antivirals, these results provide a cellular basis supporting repurposed antivirals as a strategic treatment to alleviate neurocytological defects that may underlie COVID-19- related neurological symptoms.

In-Depth Investigation of the Mechanism of Dehydration-Induced Phase Transformation from Nb3O7(OH) to H-Nb2O5: A Theoretical and Experimental Approach.

H-Nb2O5 is a promising energy material, which can be typically obtained from any other polymorph after conducting high temperature calcination (∼1273 K). Recently, a low-temperature dehydration from Nb3O7(OH) was employed to prepare H-Nb2O5 at 723 K for 2 h, and yet the transformation mechanism has remained unclear in the literature. Here, the dehydration kinetic and phase transformation mechanism of the Nb3O7(OH) were investigated for the first time by experiments, density functional theory, and molecular dynamics calculations. After dehydration, the orthorhombic Nb3O7(OH) initially transformed into an intermediate Nb-O compound with dislocations, preserving parent structure, and subsequently transformed into monoclinic H-Nb2O5. The activation energy for the transformation from Nb3O7(OH) to H-Nb2O5 was as low as 1.35 eV, compared to that of T-Nb2O5 to H-Nb2O5 (3.60 eV). Furthermore, the defect-rich H-Nb2O5 obtained from Nb3O7(OH), does not exhibit pristine bound exciton state due to severe recombination of photogenerated carriers, resulting in poor photocatalytic activity.

A case report of autoimmune GFAP astrocytopathy presenting with abnormal heart rate variability and blood pressure variability.

BACKGROUND: Autonomic dysfunctions including bladder dysfunction, gastrointestinal dysfunction and orthostasis are common symptoms of autoimmune glial fibrillary acidic protein astrocytopathy (A-GFAP-A); however, cardiac autonomic dysfunction and abnormal circadian rhythm of blood pressure, which can lead to poor prognosis and even sudden cardiac death, has never been reported in A-GFAP-A patient. CASE PRESENTATION: A 68-year-old male Chinese patient presented to our hospital with headache, fever, progressive disturbance of consciousness, dysuria, and limb weakness. Abnormal heart rate variability and non-dipper circadian rhythm of blood pressure gradually developed during hospitalization, which is rare in A-GFAP-A. He had positive GFAP IgG in cerebrospinal fluid (CSF). Enhanced brian MRI showed uneven enhancement and T2 hyperintense lesions of medulla oblongata; Cervical spine MRI showed T2 hyperintense lesions in medulla oblongata and upper margin of the T2 vertebral body. A contrast-enhanced thoracic spine MRI showed uneven enhancement and T2 hyperintense lesions of T1 to T6 vertebral segments. After treatment with intravenous immunoglobulin and corticosteroids, the patient's symptoms, including autonomic dysfunction, alleviated dramatically. Finally, his heart rate variability and blood pressure variability became normal. CONCLUSIONS: Our case broadens the spectrum of expected symptoms in A-GFAP- A syndromes as it presented with heart rate variability and blood pressure variability.

Guillain-Barre syndrome after myocardial infarction: a case report and literature review.

BACKGROUND: Guillain-Barre syndrome after myocardial infarction occurs infrequently, and its occurrence following percutaneous coronary intervention is extremely rare. Due to the high mortality rate of myocardial infarction and the disability of Guillain-Barre syndrome, early identification of Guillain-Barre syndrome after myocardial infarction and early intervention can decrease the mortality rate, lead to early recovery, and provide a better outcome. CASE PRESENTATION: Herein, we reported a rare case of Guillain-Barre syndrome after myocardial infarction treated with percutaneous coronary intervention. The patient was a 75-year-old woman from China who was admitted to hospital due to sudden loss of consciousness. Electrocardiography showed acute myocardial infarction in the right ventricle and inferior and posterior walls. The patient underwent emergency percutaneous intervention of the posterior collateral artery of the right coronary artery. Soon after, her condition worsened resulting in limb weakness and numbness. Unfortunately, she continued to develop respiratory failure, and treated with intravenous immunoglobulin and ventilator-assisted breathing. A physical examination showed hypotonia of all four limbs, complete quadriplegia, bulbar palsy, dysarthria, and tendon areflexia. Serum immunoglobulin (Ig) G anti-ganglioside antibody analysis was positive with anti-GT1a antibodies (+ +), anti-GM1 antibodies ( +), anti-GM2 antibodies ( +), and anti-GM4 antibodies ( +), and he was diagnosed with Guillain-Barre syndrome after myocardial infarction. She was discharged due to poor response to treatment. The patient died two days after being discharged. CONCLUSIONS: Myocardial infarction and/or percutaneous coronary intervention may activate immune-mediated response and cause severe complications. Clinician should be alert to Guillain-Barre syndrome after myocardial infarction and/or percutaneous coronary intervention.

Genome-scale metabolic modeling reveals SARS-CoV-2-induced metabolic changes and antiviral targets.

Tremendous progress has been made to control the COVID-19 pandemic caused by the SARS-CoV-2 virus. However, effective therapeutic options are still rare. Drug repurposing and combination represent practical strategies to address this urgent unmet medical need. Viruses, including coronaviruses, are known to hijack host metabolism to facilitate viral proliferation, making targeting host metabolism a promising antiviral approach. Here, we describe an integrated analysis of 12 published in vitro and human patient gene expression datasets on SARS-CoV-2 infection using genome-scale metabolic modeling (GEM), revealing complicated host metabolism reprogramming during SARS-CoV-2 infection. We next applied the GEM-based metabolic transformation algorithm to predict anti-SARS-CoV-2 targets that counteract the virus-induced metabolic changes. We successfully validated these targets using published drug and genetic screen data and by performing an siRNA assay in Caco-2 cells. Further generating and analyzing RNA-sequencing data of remdesivir-treated Vero E6 cell samples, we predicted metabolic targets acting in combination with remdesivir, an approved anti-SARS-CoV-2 drug. Our study provides clinical data-supported candidate anti-SARS-CoV-2 targets for future evaluation, demonstrating host metabolism targeting as a promising antiviral strategy.

Mechanical and chemical cues synergistically promote human venous smooth muscle cell osteogenesis through integrin ß1-ERK1/2 signaling: A cell model of hemodialysis fistula calcification.

Arteriovenous fistula (AVF) is the vascular access of choice for renal replacement therapy. However, AVF is susceptible to calcification with a high prevalence of 40%-65% in chronic hemodialysis patients. Repeated needle puncture for hemodialysis cannulation results in intimal denudation of AVF. We hypothesized that exposure to blood shear stress in the medial layer promotes venous smooth muscle cell (SMC) osteogenesis. While previous studies of shear stress focused on arterial-type SMCs, SMCs isolated from the vein had not been investigated. This study established a venous cell model of AVF using the fluid shear device, combined with a high phosphate medium to mimic the uremic milieu. Osteogenic gene expression of venous SMCs upon mechanical and chemical cues was analyzed in addition to the activated cell signaling pathways. Our findings indicated that upon shear stress and high phosphate environment, mechanical stimulation (shear stress) had an additive effect in up-regulation of an early osteogenic marker, Runx2. We further identified that the integrin ß1-ERK1/2 signaling pathway was responsible for the molecular basis of venous SMC osteogenesis upon shear stress exposure. Mitochondrial biogenesis also took part in the early stage of this venopathy pathogenesis, evident by the up-regulated mitochondrial transcription factor A and mitochondrial DNA polymerase γ in venous SMCs. In conclusion, synergistic effects of fluid shear stress and high phosphate induce venous SMC osteogenesis via the ERK1/2 pathway through activating the mechanosensing integrin ß1 signaling. The present study identified a promising druggable target for reducing AVF calcification, which deserves further in vivo investigations.

One-pot catalyst-free synthesis of benzopyrroxazine derivatives by a mutually activated sequential annulation process.

A one-pot catalyst-free reaction of o-hydroxyaryl azomethine ylides, vinyl pyridines and paraformaldehyde for the synthesis of benzopyrroxazines is reported, which offers a straightforward and atom-economical procedure for the preparation of benzopyrroxazine derivatives in moderate to excellent yields under mild conditions. A self-catalyzed [3 + 2] annulation through a mutual activation method and a sequential non-catalyzed [5 + 1] annulation process contribute to this strategy. The corresponding control experiments have been conducted to reveal the mechanism of this reaction.

[The destructive role of soluble Robo4 secreted by the M1-polarized-microglia during cerebral ischemia-reperfusion in blood-brain barrier integrity].

This project was aimed to investigate the role and the underlying mechanism of microglia polarization on blood-brain barrier (BBB) during cerebral ischemia-reperfusion. After construction of the mouse model of cerebral ischemia-reperfusion, upregulated IL-6 and TNF-α in peripheral blood and increased IL-6 and iNOS in ischemia tissues were confirmed. The supernatant expression of TNF-α and IL-6, as well as IL-6, iNOS and CD86 mRNA, was significantly increased in the of Bv-2 cells after oxygen-glucose deprivation/reoxygenation (OGD/R) model was constructed in vitro. For further understanding the expression pattern of RNAs, the next-generation RNA sequencing was performed and upregulation of Robo4 (roundabout guidance receptor 4) was found both in M1-polarized and OGD/R treated Bv-2 cells, which was also confirmed by RT-qPCR. Extracellular soluble Robo4 (sRobo4) protein also increased in the supernatant of M1-polarized and OGD/R treated Bv-2 cells. Treating bEND3 cells with the Robo4 recombinant protein, M1-polarized Bv-2 cell supernatant or OGD/R Bv-2 cell supernatant decreased trans-endothelial electrical resistance (TEER), suggesting the injury of BBB. In addition, Robo4 was also highly expressed in the serum of patients who experienced acute ischemia stroke and mechanical thrombectomy operation. All the results suggest that increased secretion of Robo4 by M1-polarized-microglia during cerebral ischemia-reperfusion is most likely one of the causes of BBB injury, and Robo4 may be one of the therapeutic targets for BBB functional protection.

Surface Engineering of Titanium Dioxide Nanoparticles for Silicone-Based Transparent Hybrid Films with Ultrahigh Refractive Indexes.

We report a newly developed surface engineering approach for TiO2 nanoparticles toward transparent TiO2/silicone nanocomposites with high refractive index (RI) values. Zirconate coupling agents are adopted on the TiO2 nanoparticles for surface passivation and to enhance the dispersibility of the nanoparticles in organic substrates. The modified TiO2 nanoparticles can be uniformly dispersed in silicone, forming transparent hybrid films with an ultrahigh RI of 2.01. The preparation technique of colloidal TiO2 and polymer-based nanocomposites is simple and suitable for scalable production, which is promising for expanding the application of TiO2 materials in photonic devices.

Protective effects of berberine on senile osteoporosis in mice.

INTRODUCTION: The incidence of osteoporosis is positively correlated with age. Berberine has been reported to treat osteoporosis due to its beneficial actions on bone formation. However, the direct effects of berberine on senile osteoporosis remain unclear. The present study investigated the protective effects of berberine on senile osteoporosis in mice and preliminarily evaluated its potential mechanism. MATERIALS AND METHODS: 20-month-old male C57BL/6 J mice were used as senile osteoporosis mouse model and treated with strontium ranelate (SR) or berberine or solvent control by daily gavage for 2 months. Thereafter, bone mass and microstructure parameters were assessed. Histological staining was performed to identify the osteogenic, adipogenic and osteoclastic activity of bone tissue. Moreover, role of cAMP/PKA/CREB signaling pathway in berberine affecting bone marrow mesenchymal stem cells (BMSCs) differentiation was clarified by enzyme-linked immunosorbent assay and western blot analysis. RESULTS: The results showed that the SR-treated group displayed a high trabecular bone mass phenotype. For mice administrated with berberine, cancellous bone mass was upregulated in a dose-dependent manner, as indicated by gradually increased bone mass, trabecular bone volume fraction and trabecular number. Furthermore, berberine promotes osteogenic and inhibits adipogenic differentiation of BMSCs via cAMP/PKA/CREB signaling. Also, bone resorption effect becomes more obvious with increasing dose of berberine in vitro. CONCLUSION: The present results suggest that berberine exerts potent bone protective effects by promoting bone formation, inhibiting marrow fat accumulation and bone resorption. This effect may be achieved through cAMP/PKA/CREB signaling pathway.

A Highly Controlled Organic-Inorganic Encapsulation Nanocomposite with Versatile Features toward Wearable Device Applications.

Ultraviolet-curable polyurethane acrylate (PUA) materials can be used in a number of important applications spanning from microfluidics, surface patterning to wearable technology. For the first time, the potential of encapsulation of modified zirconia (ZrO2 ) nanoparticles is reported in PUA-based hybrid films aimed to facilitate profoundly enhanced hardness and refractive index. By successfully manipulating the interfacial reaction conditions between ZrO2 nanoparticles and PUA film, the PUA-based nanocomposites exhibit an ultrahigh hardness of 9 and superior refractive index of 1.64 (589.3 nm). The outcomes obtained pave the way for seamless application of nanozirconia/PUA as a potent encapsulating material that provides structurally morphable, water resistant, and optically transparent light emitting diodes toward wearables devices in healthcare.

[Research progress in pharmacological effects of Erigeron breviscapus and its active ingredients for treatment of Alzheimer's disease].

Alzheimer's disease(AD) is a neurodegenerative disease that has no effective drug to cure it. Studies in several AD models have shown that Erigeron breviscapus and its active ingredients(scutellarin and caffeoylquinic acid) could improve/enhance the learning and memory ability, and the mechanisms are associated with inhibiting amyloid ß(Aß) production, aggregation, fibrosis and Aß neurotoxicity toxicity, regulating cholinergic nervous system, inhibiting oxidative stress and inflammation, inhibiting tau hyperphosphorylation, improving mitochondrial function, and resisting neuronal apoptosis. This article systematically reviewed the research progress of E. breviscapus and its active ingredients for treatment of AD in AD models, in the expectation of providing references for further development of E. breviscapus's medicinal potential.

CITED2 silencing sensitizes cancer cells to cisplatin by inhibiting p53 trans-activation and chromatin relaxation on the ERCC1 DNA repair gene.

In this study, we show that silencing of CITED2 using small-hairpin RNA (shCITED2) induced DNA damage and reduction of ERCC1 gene expression in HEK293, HeLa and H1299 cells, even in the absence of cisplatin. In contrast, ectopic expression of ERCC1 significantly reduced intrinsic and induced DNA damage levels, and rescued the effects of CITED2 silencing on cell viability. The effects of CITED2 silencing on DNA repair and cell death were associated with p53 activity. Furthermore, CITED2 silencing caused severe elimination of the p300 protein and markers of relaxed chromatin (acetylated H3 and H4, i.e. H3K9Ac and H3K14Ac) in HEK293 cells. Chromatin immunoprecipitation assays further revealed that DNA damage induced binding of p53 along with H3K9Ac or H3K14Ac at the ERCC1 promoter, an effect which was almost entirely abrogated by silencing of CITED2 or p300. Moreover, lentivirus-based CITED2 silencing sensitized HeLa cell line-derived tumor xenografts to cisplatin in immune-deficient mice. These results demonstrate that CITED2/p300 can be recruited by p53 at the promoter of the repair gene ERCC1 in response to cisplatin-induced DNA damage. The CITED2/p300/p53/ERCC1 pathway is thus involved in the cell response to cisplatin and represents a potential target for cancer therapy.

A comparative analysis of vaccine administration in urban and non-urban skilled nursing facilities.

BACKGROUND: The U.S. population is aging at an unprecedented rate, resulting in an increased demand for skilled nursing facilities (SNFs) and long-term care. Residents of these facilities are at a high risk for pneumococcal disease or severe influenza-related illnesses and death. For these reasons, the Centers for Medicare and Medicaid Services use influenza and pneumococcal vaccination rates as a quality measure in the assessment of SNFs, as complications related to these infections increase morbidity and mortality rates. METHODS: Disparities have been reported amongst vaccination with increased rates in urban areas as compared to their non-urban counterparts. Statistical analyses were performed to compare influenza and pneumococcal vaccination in urban and non-urban SNFs to determine variables that may influence vaccination status. RESULTS: Of the 15,639 nursing homes included in the study, 10,107 were in urban areas, while 5532 were considered non-urban. We found the percent of eligible and willing residents with up-to-date influenza and pneumococcal vaccinations increased with overall five-star ratings of SNFs. Somewhat paradoxically, although urban SNFs had higher mean overall five-star ratings, they showed lower rates of influenza and pneumococcal vaccination compared to non-urban SNFs. Ordinary least squares regression analysis comparing overall ratings, type of ownership, and geographic location by region yielded statistically significant results in which the overall rating, ownership-type and certificate-type favored urban SNFs (p < 0.001). CONCLUSIONS: This is the first systematic and comparative analysis to use the Nursing Home Compare database to assess vaccine administration of urban and non-urban SNFs. The findings of this study may be used to encourage the development of programs to improve vaccination rates and the quality of care in these facilities.