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1.
Immunity ; 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33823129

RESUMO

An effective vaccine for respiratory syncytial virus (RSV) is an unrealized public health goal. A single dose of the prefusion-stabilized fusion (F) glycoprotein subunit vaccine (DS-Cav1) substantially increases serum-neutralizing activity in healthy adults. We sought to determine whether DS-Cav1 vaccination induces a repertoire mirroring the pre-existing diversity from natural infection or whether antibody lineages targeting specific epitopes predominate. We evaluated RSV F-specific B cell responses before and after vaccination in six participants using complementary B cell sequencing methodologies and identified 555 clonal lineages. DS-Cav1-induced lineages recognized the prefusion conformation of F (pre-F) and were genetically diverse. Expressed antibodies recognized all six antigenic sites on the pre-F trimer. We identified 34 public clonotypes, and structural analysis of two antibodies from a predominant clonotype revealed a common mode of recognition. Thus, vaccination with DS-Cav1 generates a diverse polyclonal response targeting the antigenic sites on pre-F, supporting the development and advanced testing of pre-F-based vaccines against RSV.

2.
Sci Transl Med ; 2021 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-33820835

RESUMO

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) poses a public health threat for which preventive and therapeutic agents are urgently needed. Neutralizing antibodies are a key class of therapeutics which may bridge widespread vaccination campaigns and offer a treatment solution in populations less responsive to vaccination. Herein, we report that high-throughput microfluidic screening of antigen-specific B-cells led to the identification of LY-CoV555 (also known as bamlanivimab), a potent anti-spike neutralizing antibody from a hospitalized, convalescent patient with coronavirus disease 2019 (COVID-19). Biochemical, structural, and functional characterization of LY-CoV555 revealed high-affinity binding to the receptor-binding domain, angiotensin converting enzyme 2 binding inhibition, and potent neutralizing activity. A pharmacokinetic study of LY-CoV555 conducted in cynomolgus monkeys demonstrated a mean half-life of 13 days, and clearance of 0.22 mL/hr/kg, consistent with a typical human therapeutic antibody. In a rhesus macaque challenge model, prophylactic doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract in samples collected through study Day 6 following viral inoculation. This antibody has entered clinical testing and is being evaluated across a spectrum of COVID-19 indications, including prevention and treatment.

3.
Front Immunol ; 12: 615102, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732238

RESUMO

The re-emergence of Zika virus (ZIKV) caused widespread infections that were linked to Guillain-Barré syndrome in adults and congenital malformation in fetuses, and epidemiological data suggest that ZIKV infection can induce protective antibody responses. A more detailed understanding of anti-ZIKV antibody responses may lead to enhanced antibody discovery and improved vaccine designs against ZIKV and related flaviviruses. Here, we applied recently-invented library-scale antibody screening technologies to determine comprehensive functional molecular and genetic profiles of naturally elicited human anti-ZIKV antibodies in three convalescent individuals. We leveraged natively paired antibody yeast display and NGS to predict antibody cross-reactivities and coarse-grain antibody affinities, to perform in-depth immune profiling of IgM, IgG, and IgA antibody repertoires in peripheral blood, and to reveal virus maturation state-dependent antibody interactions. Repertoire-scale comparison of ZIKV VLP-specific and non-specific antibodies in the same individuals also showed that mean antibody somatic hypermutation levels were substantially influenced by donor-intrinsic characteristics. These data provide insights into antiviral antibody responses to ZIKV disease and outline systems-level strategies to track human antibody immune responses to emergent viral infections.

4.
Biochem Biophys Res Commun ; 546: 74-82, 2021 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-33578292

RESUMO

Non-alcoholic fatty liver disease (NAFLD), an emerging risk factor for diabetes, is now recognized as the most common liver disease worldwide. Mesenchymal stem cells (MSCs), a promising tool in regenerative medicine, release abundant molecules into the conditioned medium (CM). Increasing evidence showed that MSC-CM is beneficial for diabetes-associated NAFLD. However, the mechanism of how MSC-CM improves NAFLD remains uncertain. In this study, to determine the effects of MSC-CM on NAFLD, streptozotocin (STZ) and high-fat diet (HFD) induced T2DM mice model and palmitic acid (PA)-stimulated L-O2 cells were used and treated with MSC-CM. Our results demonstrated that MSC-CM improved insulin resistance in diabetic mice, amended the pathological structure of the liver, enhanced the liver's total antioxidant capacity and mitochondrial function, reduced inflammation and cell apoptosis. We further verified that SIRT1 played a key role in mediating the protective effect of MSC-CM. These findings provide novel evidence that MSC-CM has the potential to treat T2DM patients with NAFLD clinically.

5.
Sci Rep ; 10(1): 18149, 2020 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-33097791

RESUMO

Antigens displayed on self-assembling nanoparticles can stimulate strong immune responses and have been playing an increasingly prominent role in structure-based vaccines. However, the development of such immunogens is often complicated by inefficiencies in their production. To alleviate this issue, we developed a plug-and-play platform using the spontaneous isopeptide-bond formation of the SpyTag:SpyCatcher system to display trimeric antigens on self-assembling nanoparticles, including the 60-subunit Aquifex aeolicus lumazine synthase (LuS) and the 24-subunit Helicobacter pylori ferritin. LuS and ferritin coupled to SpyTag expressed well in a mammalian expression system when an N-linked glycan was added to the nanoparticle surface. The respiratory syncytial virus fusion (F) glycoprotein trimer-stabilized in the prefusion conformation and fused with SpyCatcher-could be efficiently conjugated to LuS-SpyTag or ferritin-SpyTag, enabling multivalent display of F trimers with prefusion antigenicity. Similarly, F-glycoprotein trimers from human parainfluenza virus-type 3 and spike-glycoprotein trimers from SARS-CoV-2 could be displayed on LuS nanoparticles with decent yield and antigenicity. Notably, murine vaccination with 0.08 µg of SARS-CoV-2 spike-LuS nanoparticle elicited similar neutralizing responses as 2.0 µg of spike, which was ~ 25-fold higher on a weight-per-weight basis. The versatile platform described here thus allows for multivalent plug-and-play presentation on self-assembling nanoparticles of trimeric viral antigens, with SARS-CoV-2 spike-LuS nanoparticles inducing particularly potent neutralizing responses.


Assuntos
Antígenos/imunologia , Betacoronavirus/metabolismo , Nanopartículas/química , Glicoproteína da Espícula de Coronavírus/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Antígenos/genética , Antígenos/metabolismo , Bactérias/enzimologia , Proteínas de Bactérias/genética , Betacoronavirus/isolamento & purificação , Infecções por Coronavirus , Ferritinas/genética , Helicobacter pylori/metabolismo , Humanos , Camundongos , Complexos Multienzimáticos/genética , Testes de Neutralização , Pandemias , Pneumonia Viral , Multimerização Proteica , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Propriedades de Superfície
6.
J Diabetes Res ; 2020: 3613041, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33062710

RESUMO

Objective: Diabetic kidney disease (DKD) is the most common cause of end-stage renal disease (ESRD). Even after strict control of obesity, hyperglycemia, and hypertension, some patients still progress rapidly. Previous studies suggested diabetic dyslipidemia might be one of the factors responsible for this high residual risk. This study aims to explore the impact of long-term lipid control on renal outcome in new-onset type 2 diabetes mellitus (T2DM). Methods: We conducted a 3-year follow-up study, involving 283 subjects with new-onset T2DM, and observed the effect of baseline and follow-up metabolic abnormalities, especially dyslipidemia, on the early damage of kidney function using multiple logistic regression analysis. Results: After 3 years follow-up, patients achieved a better control of body weight, hypertension, and blood glucose. The most reduced eGFR group shared the least reduced BMI and LDL-C, as well as the greatest increase in TG levels. Only TG in the follow-up, not any of the baseline data, nor obesity, blood glucose, BP, or LDL-C in the follow-up, was found to be significantly correlated with the most reduced eGFR. Compared with patients with constantly abnormal TG levels, the risks were even higher in the subjects who experienced a transition from normal TG to hypertriglyceridemia (OR = 2.576 versus OR = 2.184, after multiple adjustment), and by tight controlling of TG, patients started with abnormal baseline TG levels could reduce the risk of DKD progression to the same low levels as the TG-constantly-normal group. Conclusion: This study emphasized the importance of long-term TG control in East Asian patients with new-onset T2DM: TG control can delay the decline of kidney function in the early stage of DKD, and reversal of hypertriglyceridemia may undo the risks of the past. It is time to pay more attention to the control of TG in new-onset T2DM.

7.
bioRxiv ; 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33024963

RESUMO

SARS-CoV-2 poses a public health threat for which therapeutic agents are urgently needed. Herein, we report that high-throughput microfluidic screening of antigen-specific B-cells led to the identification of LY-CoV555, a potent anti-spike neutralizing antibody from a convalescent COVID-19 patient. Biochemical, structural, and functional characterization revealed high-affinity binding to the receptor-binding domain, ACE2 binding inhibition, and potent neutralizing activity. In a rhesus macaque challenge model, prophylaxis doses as low as 2.5 mg/kg reduced viral replication in the upper and lower respiratory tract. These data demonstrate that high-throughput screening can lead to the identification of a potent antiviral antibody that protects against SARS-CoV-2 infection. One Sentence Summary: LY-CoV555, an anti-spike antibody derived from a convalescent COVID-19 patient, potently neutralizes SARS-CoV-2 and protects the upper and lower airways of non-human primates against SARS-CoV-2 infection.

8.
Cell Rep ; 33(4): 108322, 2020 10 27.
Artigo em Inglês | MEDLINE | ID: mdl-33091382

RESUMO

Biotin-labeled molecular probes, comprising specific regions of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike, would be helpful in the isolation and characterization of antibodies targeting this recently emerged pathogen. Here, we design constructs incorporating an N-terminal purification tag, a site-specific protease-cleavage site, the probe region of interest, and a C-terminal sequence targeted by biotin ligase. Probe regions include full-length spike ectodomain as well as various subregions, and we also design mutants that eliminate recognition of the angiotensin-converting enzyme 2 (ACE2) receptor. Yields of biotin-labeled probes from transient transfection range from ∼0.5 mg/L for the complete ectodomain to >5 mg/L for several subregions. Probes are characterized for antigenicity and ACE2 recognition, and the structure of the spike ectodomain probe is determined by cryoelectron microscopy. We also characterize antibody-binding specificities and cell-sorting capabilities of the biotinylated probes. Altogether, structure-based design coupled to efficient purification and biotinylation processes can thus enable streamlined development of SARS-CoV-2 spike ectodomain probes.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Infecções por Coronavirus/imunologia , Sondas Moleculares/imunologia , Pneumonia Viral/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Especificidade de Anticorpos/imunologia , Sítios de Ligação de Anticorpos/imunologia , Biotinilação , Microscopia Crioeletrônica , Humanos , Pandemias , Peptidil Dipeptidase A/metabolismo , Receptores Virais/metabolismo
9.
Cell Rep ; 32(9): 108088, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32877670

RESUMO

Multidonor antibodies are of interest for vaccine design because they can in principle be elicited in the general population by a common set of immunogens. For influenza, multidonor antibodies have been observed against the hemagglutinin (HA) stem, but not the immunodominant HA head. Here, we identify and characterize a multidonor antibody class (LPAF-a class) targeting the HA head. This class exhibits potent viral entry inhibition against H1N1 A/California/04/2009 (CA09) virus. LPAF-a class antibodies derive from the HV2-70 gene and contain a "Tyr-Gly-Asp"-motif, which occludes the HA-sialic acid binding site as revealed by a co-crystal structure with HA. Both germline-reverted and mature LPAF antibodies potently neutralize CA09 virus and have nanomolar affinities for CA09 HA. Moreover, increased frequencies for LPFA-a class antibodies are observed in humans after a single vaccination. Overall, this work highlights the identification of a multidonor class of head-directed influenza-neutralizing antibodies and delineates the mechanism of their recurrent elicitation in humans.

10.
Nature ; 586(7830): 567-571, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32756549

RESUMO

A vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is needed to control the coronavirus disease 2019 (COVID-19) global pandemic. Structural studies have led to the development of mutations that stabilize Betacoronavirus spike proteins in the prefusion state, improving their expression and increasing immunogenicity1. This principle has been applied to design mRNA-1273, an mRNA vaccine that encodes a SARS-CoV-2 spike protein that is stabilized in the prefusion conformation. Here we show that mRNA-1273 induces potent neutralizing antibody responses to both wild-type (D614) and D614G mutant2 SARS-CoV-2 as well as CD8+ T cell responses, and protects against SARS-CoV-2 infection in the lungs and noses of mice without evidence of immunopathology. mRNA-1273 is currently in a phase III trial to evaluate its efficacy.


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/imunologia , Betacoronavirus/genética , Linfócitos T CD8-Positivos/imunologia , Ensaios Clínicos Fase III como Assunto , Infecções por Coronavirus/genética , Infecções por Coronavirus/virologia , Feminino , Pulmão/imunologia , Pulmão/virologia , Camundongos , Mutação , Nariz/imunologia , Nariz/virologia , Pneumonia Viral/virologia , RNA Mensageiro/genética , RNA Viral/genética , Células Th1/imunologia , Receptor 4 Toll-Like/agonistas , Receptor 4 Toll-Like/imunologia , Vacinas Virais/química , Vacinas Virais/genética
11.
SSRN ; : 3639618, 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32742241

RESUMO

Biotin-labeled molecular probes, comprising specific regions of the SARS-CoV-2 spike, would be helpful in the isolation and characterization of antibodies targeting this recently emerged pathogen. To develop such probes, we designed constructs incorporating an N-terminal purification tag, a site-specific protease-cleavage site, the probe region of interest, and a C-terminal sequence targeted by biotin ligase. Probe regions included full-length spike ectodomain as well as various subregions, and we also designed mutants to eliminate recognition of the ACE2 receptor. Yields of biotin-labeled probes from transient transfection ranged from ~0.5 mg/L for the complete ectodomain to >5 mg/L for several subregions. Probes were characterized for antigenicity and ACE2 recognition, and the structure of the spike ectodomain probe was determined by cryo-electron microscopy. We also characterized antibody-binding specificities and cell-sorting capabilities of the biotinylated probes. Altogether, structure-based design coupled to efficient purification and biotinylation processes can thus enable streamlined development of SARS-CoV-2 spike-ectodomain probes. Funding: Support for this work was provided by the Intramural Research Program of the Vaccine Research Center, National Institute of Allergy and Infectious Diseases (NIAID). Support for this work was also provided by COVID-19 Fast Grants, the Jack Ma Foundation, the Self Graduate Fellowship Program, and NIH grants DP5OD023118, R21AI143407, and R21AI144408. Some of this work was performed at the Columbia University Cryo-EM Center at the Zuckerman Institute, and some at the Simons Electron Microscopy Center (SEMC) and National Center for Cryo-EM Access and Training (NCCAT) located at the New York Structural Biology Center, supported by grants from the Simons Foundation (SF349247), NYSTAR, and the NIH National Institute of General Medical Sciences (GM103310). Conflict of Interest: The authors declare that they have no conflict of interest. Ethical Approval: Peripheral blood mononuclear cells (PBMCs) for B cell sorting were obtained from a convalescent SARS-CoV-2 patient (collected 75 days post symptom onset under an IRB approved clinical trial protocol, VRC 200 - ClinicalTrials.gov Identifier: NCT00067054) and a healthy control donor from the NIH blood bank pre-SARS-CoV-2 pandemic.

12.
N Engl J Med ; 383(16): 1544-1555, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-32722908

RESUMO

BACKGROUND: Vaccines to prevent coronavirus disease 2019 (Covid-19) are urgently needed. The effect of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines on viral replication in both upper and lower airways is important to evaluate in nonhuman primates. METHODS: Nonhuman primates received 10 or 100 µg of mRNA-1273, a vaccine encoding the prefusion-stabilized spike protein of SARS-CoV-2, or no vaccine. Antibody and T-cell responses were assessed before upper- and lower-airway challenge with SARS-CoV-2. Active viral replication and viral genomes in bronchoalveolar-lavage (BAL) fluid and nasal swab specimens were assessed by polymerase chain reaction, and histopathological analysis and viral quantification were performed on lung-tissue specimens. RESULTS: The mRNA-1273 vaccine candidate induced antibody levels exceeding those in human convalescent-phase serum, with live-virus reciprocal 50% inhibitory dilution (ID50) geometric mean titers of 501 in the 10-µg dose group and 3481 in the 100-µg dose group. Vaccination induced type 1 helper T-cell (Th1)-biased CD4 T-cell responses and low or undetectable Th2 or CD8 T-cell responses. Viral replication was not detectable in BAL fluid by day 2 after challenge in seven of eight animals in both vaccinated groups. No viral replication was detectable in the nose of any of the eight animals in the 100-µg dose group by day 2 after challenge, and limited inflammation or detectable viral genome or antigen was noted in lungs of animals in either vaccine group. CONCLUSIONS: Vaccination of nonhuman primates with mRNA-1273 induced robust SARS-CoV-2 neutralizing activity, rapid protection in the upper and lower airways, and no pathologic changes in the lung. (Funded by the National Institutes of Health and others.).


Assuntos
Betacoronavirus/imunologia , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/prevenção & controle , Pandemias/prevenção & controle , Pneumonia Viral/imunologia , Pneumonia Viral/prevenção & controle , Vacinas Virais/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Betacoronavirus/fisiologia , Antígenos CD4 , Infecções por Coronavirus/patologia , Infecções por Coronavirus/terapia , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Imunização Passiva , Pulmão/patologia , Pulmão/virologia , Macaca mulatta , Pneumonia Viral/patologia , Pneumonia Viral/terapia , Glicoproteína da Espícula de Coronavírus , Linfócitos T/imunologia , Carga Viral , Vacinas Virais/administração & dosagem , Replicação Viral
13.
Cell Host Microbe ; 28(3): 434-444.e4, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32619441

RESUMO

Understanding how broadly neutralizing antibodies (bnAbs) to influenza hemagglutinin (HA) naturally develop in humans is critical to the design of universal influenza vaccines. Several classes of bnAbs directed to the conserved HA stem were found in multiple individuals, including one encoded by heavy-chain variable domain VH6-1. We describe two genetically similar VH6-1 bnAb clonotypes from the same individual that exhibit different developmental paths toward broad neutralization activity. One clonotype evolved from a germline precursor recognizing influenza group 1 subtypes to gain breadth to group 2 subtypes. The other clonotype recognized group 2 subtypes and developed binding to group 1 subtypes through somatic hypermutation. Crystal structures reveal that the specificity differences are primarily mediated by complementarity-determining region H3 (CDR H3). Thus, while VH6-1 provides a framework for development of HA stem-directed bnAbs, sequence differences in CDR H3 junctional regions during VDJ recombination can alter reactivity and evolutionary pathways toward increased breadth.

14.
bioRxiv ; 2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32676596

RESUMO

Antigens displayed on self-assembling nanoparticles can stimulate strong immune responses and have been playing an increasingly prominent role in structure-based vaccines. However, the development of such immunogens may be complicated by inefficiencies in their production, especially with the metastable glycosylated trimeric type 1 fusion machines that are prevalent viral vaccine targets. To alleviate this issue, we developed a plug-and-play platform using the spontaneous isopeptide-bond formation of the SpyTag:SpyCatcher system to display trimeric antigens on self-assembling nanoparticles, including the 60-subunit Aquifex aeolicus lumazine synthase (LuS) and the 24-subunit Helicobacter pylori ferritin. LuS and ferritin coupled to SpyTag expressed well in a mammalian expression system when an N- linked glycan was added to the nanoparticle surface. Respiratory syncytial virus fusion (F) glycoprotein trimer - stabilized in the prefusion conformation by multiple disulfides and fused with SpyCatcher - could be efficiently conjugated to LuS-SpyTag or to ferritin-SpyTag, enabling multivalent display of F trimers with prefusion antigenicity. Similarly, F-glycoprotein trimers from human parainfluenza virus-type 3 and spike-glycoprotein trimers from SARS-CoV-2 could be displayed on LuS nanoparticles with decent yield and antigenicity. The versatile platform described here thus allows for multivalent plug-and-play presentation on self-assembling nanoparticles of trimeric antigens from viral respiratory pathogens, including the recently identified SARS-CoV-2.

15.
Metabolism ; 109: 154290, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32522488

RESUMO

BACKGROUND: Males absent on the first (Mof) is implicated in gene control of diverse biological processes, such as cell growth, differentiation, apoptosis and autophagy. However, the relationship between glucose regulation and Mof-mediated transcription events remains unexplored. We aimed to unravel the role of Mof in glucose regulation by using global and pancreatic α-cell-specific Mof-deficient mice in vivo and α-TC1-6 cell line in vitro. METHODS: We used tamoxifen-induced temporal Mof-deficient mice first to show Mof regulate glucose homeostasis, islet cell proportions and hormone secretion. Then we used α-cell-specific Mof-deficient mice to clarify how α-cell subsets and ß-cell mass were regulated and corresponding hormone level alterations. Ultimately, we used small interfering RNA (siRNA) to knockdown Mof in α-TC1-6 and unravel the mechanism regulating α-cell mass and glucagon secretion. RESULTS: Mof was mainly expressed in α-cells. Global Mof deficiency led to lower glucose levels, attributed by decreased α/ß-cell ratio and glucagon secretion. α-cell-specific Mof-deficient mice exhibited similar alterations, with more reduced prohormone convertase 2 (PC2)-positive α-cell mass, responsible for less glucagon, and enhanced prohormone convertase 1 (PC1/3)-positive α-cell mass, leading to more glucagon-like peptide-1 (GLP-1) secretion, thus increased ß-cell mass and insulin secretion. In vitro, increased DNA damage, dysregulated autophagy, enhanced apoptosis and altered cell fate factors expressions upon Mof knockdown were observed. Genes and pathways linked to impaired glucagon secretion were uncovered through transcriptome sequencing. CONCLUSION: Mof is a potential interventional target for glucose regulation, from the aspects of both α-cell subset mass and glucagon, intra-islet GLP-1 secretion. Upon Mof deficiency, Up-regulated PC1/3 but down-regulated PC2-positive α-cell mass, leads to more GLP-1 and insulin but less glucagon secretion, and contributed to lower glucose level.


Assuntos
Glicemia/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Células Secretoras de Glucagon/citologia , Glucagon/metabolismo , Histona Acetiltransferases/fisiologia , Homeostase , Animais , Linhagem Celular , Histona Acetiltransferases/deficiência , Insulina/metabolismo , Ilhotas Pancreáticas/metabolismo , Camundongos , Pró-Proteína Convertase 1/metabolismo , Pró-Proteína Convertase 2/metabolismo
16.
bioRxiv ; 2020 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-32577634

RESUMO

A SARS-CoV-2 vaccine is needed to control the global COVID-19 public health crisis. Atomic-level structures directed the application of prefusion-stabilizing mutations that improved expression and immunogenicity of betacoronavirus spike proteins. Using this established immunogen design, the release of SARS-CoV-2 sequences triggered immediate rapid manufacturing of an mRNA vaccine expressing the prefusion-stabilized SARS-CoV-2 spike trimer (mRNA-1273). Here, we show that mRNA-1273 induces both potent neutralizing antibody and CD8 T cell responses and protects against SARS-CoV-2 infection in lungs and noses of mice without evidence of immunopathology. mRNA-1273 is currently in a Phase 2 clinical trial with a trajectory towards Phase 3 efficacy evaluation.

17.
bioRxiv ; 2020 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-32596696

RESUMO

Biotin-labeled molecular probes, comprising specific regions of the SARS-CoV-2 spike, would be helpful in the isolation and characterization of antibodies targeting this recently emerged pathogen. To develop such probes, we designed constructs incorporating an N-terminal purification tag, a site-specific protease-cleavage site, the probe region of interest, and a C-terminal sequence targeted by biotin ligase. Probe regions included full-length spike ectodomain as well as various subregions, and we also designed mutants to eliminate recognition of the ACE2 receptor. Yields of biotin-labeled probes from transient transfection ranged from ~0.5 mg/L for the complete ectodomain to >5 mg/L for several subregions. Probes were characterized for antigenicity and ACE2 recognition, and the structure of the spike ectodomain probe was determined by cryo-electron microscopy. We also characterized antibody-binding specificities and cell-sorting capabilities of the biotinylated probes. Altogether, structure-based design coupled to efficient purification and biotinylation processes can thus enable streamlined development of SARS-CoV-2 spike-ectodomain probes.

18.
Stem Cell Res Ther ; 11(1): 223, 2020 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-32513303

RESUMO

BACKGROUND: Mesenchymal stem cell (MSC)-based therapy is currently considered to be an effective treatment strategy for diabetes and hepatic disorders, such as liver cirrhosis and non-alcoholic fatty liver disease. Exosomes are important mediators of cellular connections, and increasing evidence has suggested that exosomes derived from MSCs may be used as direct therapeutic agents; their mechanisms of action, however, remain largely unclear. Here, we evaluated the efficacy and molecular mechanisms of human umbilical cord MSC-derived exosomes (HucMDEs) on hepatic glucose and lipid metabolism in type 2 diabetes mellitus (T2DM). METHODS: HucMDEs were used to treat T2DM rats, as well as palmitic acid (PA)-treated L-O2 cells, in order to determine the effects of HucMDEs on hepatic glucose and lipid metabolism. To evaluate the changes in autophagy and potential signaling pathways, autophagy-related proteins (BECN1, microtubule-associated protein 1 light chain 3 beta [MAP 1LC3B]), autophagy-related genes (ATGs, ATG5, and ATG7), AMP-activated protein kinase (AMPK), and phosphorylated AMPK (p-AMPK) were assessed by Western blotting. RESULTS: HucMDEs promoted hepatic glycolysis, glycogen storage, and lipolysis, and reduced gluconeogenesis. Additionally, autophagy potentially contributed to the effects of HucMDE treatment. Transmission electron microscopy revealed an increased formation of autophagosomes in HucMDE-treated groups, and the autophagy marker proteins, BECN1 and MAP 1LC3B, were also increased. Moreover, autophagy inhibitor 3-methyladenine significantly reduced the effects of HucMDEs on glucose and lipid metabolism in T2DM rats. Based on its phosphorylation status, we found that the AMPK signaling pathway was activated and induced autophagy in T2DM rats and PA-treated L-O2 cells. Meanwhile, the transfection of AMPK siRNA or application of the AMPK inhibitor, Comp C, weakened the therapeutic effects of HucMDEs on glucose and lipid metabolism. CONCLUSIONS: These findings demonstrate that HucMDEs improved hepatic glucose and lipid metabolism in T2DM rats by activating autophagy via the AMPK pathway, which provides novel evidence suggesting the potential for HucMDEs in clinically treating T2DM patients.

19.
PLoS One ; 15(5): e0232757, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32384116

RESUMO

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory infection and continues to infect humans, thereby contributing to a high mortality rate (34.3% in 2019). In the absence of an available licensed vaccine and antiviral agent, therapeutic human antibodies have been suggested as candidates for treatment. In this study, human monoclonal antibodies were isolated by sorting B cells from patient's PBMC cells with prefusion stabilized spike (S) probes and a direct immunoglobulin cloning strategy. We identified six receptor-binding domain (RBD)-specific and five S1 (non-RBD)-specific antibodies, among which, only the RBD-specific antibodies showed high neutralizing potency (IC50 0.006-1.787 µg/ml) as well as high affinity to RBD. Notably, passive immunization using a highly potent antibody (KNIH90-F1) at a relatively low dose (2 mg/kg) completely protected transgenic mice expressing human DPP4 against MERS-CoV lethal challenge. These results suggested that human monoclonal antibodies isolated by using the rationally designed prefusion MERS-CoV S probe could be considered potential candidates for the development of therapeutic and/or prophylactic antiviral agents for MERS-CoV human infection.


Assuntos
Anticorpos Monoclonais/farmacologia , Anticorpos Antivirais/farmacologia , Infecções por Coronavirus/tratamento farmacológico , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Anticorpos Neutralizantes/farmacologia , Anticorpos Antivirais/imunologia , Antivirais/farmacologia , Linhagem Celular , Chlorocebus aethiops , Dipeptidil Peptidase 4/genética , Humanos , Leucócitos Mononucleares/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , República da Coreia , Células Vero
20.
J Diabetes Res ; 2020: 6047145, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32064276

RESUMO

Background: More and more studies focus on the relationship between the gastrointestinal microbiome and type 2 diabetes, but few of them have actually explored the relationship between enterotypes and type 2 diabetes. Materials and Methods. We enrolled 134 patients with type 2 diabetes and 37 nondiabetic controls. The anthropometric and clinical indices of each subject were measured. Fecal samples of each subject were also collected and were processed for 16S rDNA sequencing. Multiple logistic regression analysis was used to determine the associations of enterotypes with type 2 diabetes. Multiple linear regression analysis was used to explore the relationship between lipopolysaccharide levels and insulin sensitivity after adjusting for age, BMI, TG, HDL-C, DAO, and TNF-α. The correlation analysis between factors and microbiota was identified using Spearman correlation analysis. The correlation analysis between factors was identified using partial correlation analysis. Results: Gut microbiota in type 2 diabetes group exhibited lower bacterial diversity compared with nondiabetic controls. The fecal communities from all subjects clustered into two enterotypes distinguished by the levels of Bacteroides and Prevotella. Logistic regression analysis showed that the Bacteroides and Bacteroides and Prevotella enterotype. Partial correlation analysis showed that lipopolysaccharide was closely associated with diamine oxidase, tumor necrosis factor-alpha, and Gutt insulin sensitivity index after adjusting for multiple covariates. Furthermore, the level of lipopolysaccharide was found to be an independent risk factor for insulin sensitivity. Conclusions: We identified two enterotypes, Bacteroides and Prevotella, among all subjects. Our results showed that the Bacteroides enterotype was an independent risk factor for type 2 diabetes, which was due to increased levels of lipopolysaccharide causing decreased insulin sensitivity.Bacteroides and Prevotella enterotype. Partial correlation analysis showed that lipopolysaccharide was closely associated with diamine oxidase, tumor necrosis factor-alpha, and Gutt insulin sensitivity index after adjusting for multiple covariates. Furthermore, the level of lipopolysaccharide was found to be an independent risk factor for insulin sensitivity. Bacteroides and.

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