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1.
Annu Rev Immunol ; 39: 103-129, 2021 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-33472004

RESUMO

B cell subsets differ in development, tissue distribution, and mechanisms of activation. In response to infections, however, all can differentiate into extrafollicular plasmablasts that rapidly provide highly protective antibodies, indicating that these plasmablasts are the main humoral immune response effectors. Yet, the effectiveness of this response type depends on the presence of antigen-specific precursors in the circulating mature B cell pool, a pool that is generated initially through the stochastic processes of B cell receptor assembly. Importantly, germinal centers then mold the repertoire of this B cell pool to be increasingly responsive to pathogens by generating a broad array of antimicrobial memory B cells that act as highly effective precursors of extrafollicular plasmablasts. Such B cell repertoire molding occurs in two ways: continuously via the chronic germinal centers of mucosal lymphoid tissues, driven by the presence of the microbiome, and via de novo generated germinal centers following acute infections. For effectively evaluating humoral immunity as a correlate of immune protection, it might be critical to measure memory B cell pools in addition to antibody titers.


Assuntos
Subpopulações de Linfócitos B , Linfócitos B , Animais , Centro Germinativo , Humanos , Imunidade Humoral , Receptores de Antígenos de Linfócitos B
2.
Cell ; 186(12): 2690-2704.e20, 2023 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-37295405

RESUMO

Biofilm formation is generally recognized as a bacterial defense mechanism against environmental threats, including antibiotics, bacteriophages, and leukocytes of the human immune system. Here, we show that for the human pathogen Vibrio cholerae, biofilm formation is not only a protective trait but also an aggressive trait to collectively predate different immune cells. We find that V. cholerae forms biofilms on the eukaryotic cell surface using an extracellular matrix comprising primarily mannose-sensitive hemagglutinin pili, toxin-coregulated pili, and the secreted colonization factor TcpF, which differs from the matrix composition of biofilms on other surfaces. These biofilms encase immune cells and establish a high local concentration of a secreted hemolysin to kill the immune cells before the biofilms disperse in a c-di-GMP-dependent manner. Together, these results uncover how bacteria employ biofilm formation as a multicellular strategy to invert the typical relationship between human immune cells as the hunters and bacteria as the hunted.


Assuntos
Vibrio cholerae , Animais , Humanos , Vibrio cholerae/metabolismo , Comportamento Predatório , Biofilmes , Fímbrias Bacterianas , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica
3.
Cell ; 184(14): 3774-3793.e25, 2021 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-34115982

RESUMO

Cytomegaloviruses (CMVs) have co-evolved with their mammalian hosts for millions of years, leading to remarkable host specificity and high infection prevalence. Macrophages, which already populate barrier tissues in the embryo, are the predominant immune cells at potential CMV entry sites. Here we show that, upon CMV infection, macrophages undergo a morphological, immunophenotypic, and metabolic transformation process with features of stemness, altered migration, enhanced invasiveness, and provision of the cell cycle machinery for viral proliferation. This complex process depends on Wnt signaling and the transcription factor ZEB1. In pulmonary infection, mouse CMV primarily targets and reprograms alveolar macrophages, which alters lung physiology and facilitates primary CMV and secondary bacterial infection by attenuating the inflammatory response. Thus, CMV profoundly perturbs macrophage identity beyond established limits of plasticity and rewires specific differentiation processes, allowing viral spread and impairing innate tissue immunity.


Assuntos
Citomegalovirus/fisiologia , Macrófagos Alveolares/virologia , Animais , Apresentação de Antígeno , Efeito Espectador , Ciclo Celular , Linhagem Celular Transformada , Reprogramação Celular , Citomegalovirus/patogenicidade , Citomegalovirus/ultraestrutura , Infecções por Citomegalovirus/imunologia , Infecções por Citomegalovirus/virologia , Proteínas de Fluorescência Verde/metabolismo , Pulmão/patologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/ultraestrutura , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Fenótipo , Células-Tronco/patologia , Replicação Viral/fisiologia , Via de Sinalização Wnt
4.
Cell ; 182(5): 1311-1327.e14, 2020 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-32888495

RESUMO

Staphylococcus aureus bacteremia (SaB) causes significant disease in humans, carrying mortality rates of ∼25%. The ability to rapidly predict SaB patient responses and guide personalized treatment regimens could reduce mortality. Here, we present a resource of SaB prognostic biomarkers. Integrating proteomic and metabolomic techniques enabled the identification of >10,000 features from >200 serum samples collected upon clinical presentation. We interrogated the complexity of serum using multiple computational strategies, which provided a comprehensive view of the early host response to infection. Our biomarkers exceed the predictive capabilities of those previously reported, particularly when used in combination. Last, we validated the biological contribution of mortality-associated pathways using a murine model of SaB. Our findings represent a starting point for the development of a prognostic test for identifying high-risk patients at a time early enough to trigger intensive monitoring and interventions.


Assuntos
Bacteriemia/sangue , Bacteriemia/mortalidade , Infecções Estafilocócicas/sangue , Infecções Estafilocócicas/mortalidade , Staphylococcus aureus/patogenicidade , Animais , Bacteriemia/metabolismo , Biomarcadores/sangue , Biomarcadores/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Masculino , Metabolômica/métodos , Camundongos , Pessoa de Meia-Idade , Prognóstico , Proteômica/métodos , Fatores de Risco , Infecções Estafilocócicas/metabolismo
5.
Cell ; 177(3): 683-696.e18, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30929902

RESUMO

Microbiota and intestinal epithelium restrict pathogen growth by rapid nutrient consumption. We investigated how pathogens circumvent this obstacle to colonize the host. Utilizing enteropathogenic E. coli (EPEC), we show that host-attached bacteria obtain nutrients from infected host cell in a process we termed host nutrient extraction (HNE). We identified an inner-membrane protein complex, henceforth termed CORE, as necessary and sufficient for HNE. The CORE is a key component of the EPEC injectisome, however, here we show that it supports the formation of an alternative structure, composed of membranous nanotubes, protruding from the EPEC surface to directly contact the host. The injectisome and flagellum are evolutionarily related, both containing conserved COREs. Remarkably, CORE complexes of diverse ancestries, including distant flagellar COREs, could rescue HNE capacity of EPEC lacking its native CORE. Our results support the notion that HNE is a widespread virulence strategy, enabling pathogens to thrive in competitive niches.


Assuntos
Escherichia coli Enteropatogênica/patogenicidade , Proteínas de Escherichia coli/metabolismo , Nutrientes/metabolismo , Aminoácidos/metabolismo , Aderência Bacteriana/fisiologia , Escherichia coli Enteropatogênica/crescimento & desenvolvimento , Escherichia coli Enteropatogênica/metabolismo , Fluoresceínas/metabolismo , Células HeLa , Humanos , Proteínas de Membrana/metabolismo , Microscopia Eletrônica de Varredura , Microscopia de Fluorescência
6.
Cell ; 174(5): 1158-1171.e19, 2018 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-30057110

RESUMO

Characterizing cell surface receptors mediating viral infection is critical for understanding viral tropism and developing antiviral therapies. Nevertheless, due to challenges associated with detecting protein interactions on the cell surface, the host receptors of many human pathogens remain unknown. Here, we build a library consisting of most single transmembrane human receptors and implement a workflow for unbiased and high-sensitivity detection of receptor-ligand interactions. We apply this technology to elucidate the long-sought receptor of human cytomegalovirus (HCMV), the leading viral cause of congenital birth defects. We identify neuropilin-2 (Nrp2) as the receptor for HCMV-pentamer infection in epithelial/endothelial cells and uncover additional HCMV interactors. Using a combination of biochemistry, cell-based assays, and electron microscopy, we characterize the pentamer-Nrp2 interaction and determine the architecture of the pentamer-Nrp2 complex. This work represents an important approach to the study of host-pathogen interactions and provides a framework for understanding HCMV infection, neutralization, and the development of novel anti-HCMV therapies.


Assuntos
Infecções por Citomegalovirus/metabolismo , Citomegalovirus/fisiologia , Neuropilina-2/metabolismo , Receptores Virais/metabolismo , Anticorpos Neutralizantes/química , Membrana Celular/metabolismo , Células Endoteliais/metabolismo , Células Epiteliais/metabolismo , Mapeamento de Epitopos , Feminino , Células HEK293 , Humanos , Conformação Proteica , Proteínas do Envelope Viral/metabolismo , Internalização do Vírus
7.
Cell ; 174(4): 917-925.e10, 2018 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-30033364

RESUMO

Bacteria utilize CRISPR-Cas adaptive immune systems for protection from bacteriophages (phages), and some phages produce anti-CRISPR (Acr) proteins that inhibit immune function. Despite thorough mechanistic and structural information for some Acr proteins, how they are deployed and utilized by a phage during infection is unknown. Here, we show that Acr production does not guarantee phage replication when faced with CRISPR-Cas immunity, but instead, infections fail when phage population numbers fall below a critical threshold. Infections succeed only if a sufficient Acr dose is contributed to a single cell by multiple phage genomes. The production of Acr proteins by phage genomes that fail to replicate leave the cell immunosuppressed, which predisposes the cell for successful infection by other phages in the population. This altruistic mechanism for CRISPR-Cas inhibition demonstrates inter-virus cooperation that may also manifest in other host-parasite interactions.


Assuntos
Bacteriófagos/imunologia , Sistemas CRISPR-Cas/imunologia , Interações Hospedeiro-Patógeno/imunologia , Pseudomonas aeruginosa/imunologia , Pseudomonas aeruginosa/virologia , Proteínas Virais/imunologia , Evolução Molecular , Pseudomonas aeruginosa/genética , Proteínas Virais/metabolismo
8.
Cell ; 173(5): 1231-1243.e16, 2018 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-29731171

RESUMO

Ubiquitination constitutes one of the most important signaling mechanisms in eukaryotes. Conventional ubiquitination is catalyzed by the universally conserved E1-E2-E3 three-enzyme cascade in an ATP-dependent manner. The newly identified SidE family effectors of the pathogen Legionella pneumophila ubiquitinate several human proteins by a different mechanism without engaging any of the conventional ubiquitination machinery. We now report the crystal structures of SidE alone and in complex with ubiquitin, NAD, and ADP-ribose, thereby capturing different conformations of SidE before and after ubiquitin and ligand binding. The structures of ubiquitin bound to both mART and PDE domains reveal several unique features of the two reaction steps catalyzed by SidE. Further, the structural and biochemical results demonstrate that SidE family members do not recognize specific structural folds of the substrate proteins. Our studies provide both structural explanations for the functional observations and new insights into the molecular mechanisms of this non-canonical ubiquitination machinery.


Assuntos
Proteínas de Bactérias/química , Legionella pneumophila/metabolismo , Diester Fosfórico Hidrolases/química , Ubiquitina/química , Proteínas de Bactérias/metabolismo , Biocatálise , Cristalografia por Raios X , Dimerização , Diester Fosfórico Hidrolases/metabolismo , Ligação Proteica , Domínios Proteicos , Estrutura Quaternária de Proteína , Ubiquitina/metabolismo , Ubiquitinação
9.
Mol Cell ; 81(13): 2823-2837.e9, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34015248

RESUMO

DNA-induced liquid-liquid phase separation of cyclic GMP-AMP synthase (cGAS) triggers a potent response to detect pathogen infection and promote innate immune signaling. Whether and how pathogens manipulate cGAS-DNA condensation to mediate immune evasion is unknown. We report the identification of a structurally related viral tegument protein family, represented by ORF52 and VP22 from gamma- and alpha-herpesvirinae, respectively, that employs a conserved mechanism to restrict cGAS-DNA phase separation. ORF52/VP22 proteins accumulate into, and effectively disrupt, the pre-formed cGAS-DNA condensation both in vitro and in cells. The inhibition process is dependent on DNA-induced liquid-liquid phase separation of the viral protein rather than a direct interaction with cGAS. Moreover, highly abundant ORF52 proteins carried within viral particles are able to target cGAS-DNA phase separation in early infection stage. Our results define ORF52/VP22-type tegument proteins as a family of inhibitors targeting cGAS-DNA phase separation and demonstrate a mechanism for how viruses overcome innate immunity.


Assuntos
Alphaherpesvirinae , Betaherpesvirinae , DNA , Infecções por Herpesviridae , Evasão da Resposta Imune , Nucleotidiltransferases , Proteínas Estruturais Virais , Alphaherpesvirinae/química , Alphaherpesvirinae/genética , Alphaherpesvirinae/imunologia , Betaherpesvirinae/química , Betaherpesvirinae/genética , Betaherpesvirinae/imunologia , DNA/química , DNA/genética , DNA/imunologia , Células HEK293 , Células HeLa , Infecções por Herpesviridae/genética , Infecções por Herpesviridae/imunologia , Humanos , Imunidade Inata , Nucleotidiltransferases/química , Nucleotidiltransferases/genética , Nucleotidiltransferases/imunologia , Proteínas Estruturais Virais/química , Proteínas Estruturais Virais/genética , Proteínas Estruturais Virais/imunologia
10.
Proc Natl Acad Sci U S A ; 121(25): e2316143121, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38861595

RESUMO

Vibrio vulnificus causes life-threatening wound and gastrointestinal infections, mediated primarily by the production of a Multifunctional-Autoprocessing Repeats-In-Toxin (MARTX) toxin. The most commonly present MARTX effector domain, the Makes Caterpillars Floppy-like (MCF) toxin, is a cysteine protease stimulated by host adenosine diphosphate (ADP) ribosylation factors (ARFs) to autoprocess. Here, we show processed MCF then binds and cleaves host Ras-related proteins in brain (Rab) guanosine triphosphatases within their C-terminal tails resulting in Rab degradation. We demonstrate MCF binds Rabs at the same interface occupied by ARFs. Moreover, we show MCF preferentially binds to ARF1 prior to autoprocessing and is active to cleave Rabs only subsequent to autoprocessing. We then use structure prediction algorithms to demonstrate that structural composition, rather than sequence, determines Rab target specificity. We further determine a crystal structure of aMCF as a swapped dimer, revealing an alternative conformation we suggest represents the open, activated state of MCF with reorganized active site residues. The cleavage of Rabs results in Rab1B dispersal within cells and loss of Rab1B density in the intestinal tissue of infected mice. Collectively, our work describes an extracellular bacterial mechanism whereby MCF is activated by ARFs and subsequently induces the degradation of another small host guanosine triphosphatase (GTPase), Rabs, to drive organelle damage, cell death, and promote pathogenesis of these rapidly fatal infections.


Assuntos
Toxinas Bacterianas , Vibrio vulnificus , Proteínas rab de Ligação ao GTP , Animais , Feminino , Humanos , Camundongos , Fatores de Ribosilação do ADP/metabolismo , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/química , Células HEK293 , Camundongos Endogâmicos ICR , Proteólise , Proteínas rab de Ligação ao GTP/metabolismo , Vibrioses/microbiologia , Vibrioses/metabolismo , Vibrio vulnificus/metabolismo , Vibrio vulnificus/patogenicidade
11.
Proc Natl Acad Sci U S A ; 121(17): e2319605121, 2024 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-38578984

RESUMO

The germ theory states that pathogenic microorganisms are responsible for causing infectious diseases. The theory is inherently microbe-centric and does not account for variability in disease severity among individuals and asymptomatic carriership-two phenomena indicating an important role for host variability in infection outcome. The basic tenet of the germ theory was recently challenged, and a radically host-centric paradigm referred to as the "full-blown host theory" was proposed. According to this view, the pathogen is reduced to a passive environmental trigger, and the development of disease is instead due to pre-existing immunodeficiencies of the host. Here, we consider the factors that determine disease severity using established knowledge concerning evolutionary biology, microbial pathogenesis, and host-pathogen interactions. We note that the available data support a noncentric view that recognizes key roles for both the causative microbe and the host in dictating infection outcome.


Assuntos
Teoria do Germe da Doença , Interações Hospedeiro-Patógeno , Humanos
12.
J Cell Sci ; 137(10)2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38660993

RESUMO

Zika virus (ZIKV) has gained notoriety in recent years because there are no targeted therapies or vaccines available so far. Caveolin-1 (Cav-1) in host cells plays crucial functions in the invasion of many viruses. However, its specific involvement in ZIKV infection has remained unclear. Here, we reveal that depleting Cav-1 leads to a substantial reduction in ZIKV RNA levels, protein expression and viral particle production, indicating that ZIKV exploits Cav-1 for its infection. By dissecting each stage of the viral life cycle, we unveil that, unlike its invasion role in many other viruses, Cav-1 depletion selectively impairs ZIKV replication, resulting in altered replication dynamics and reduced strand-specific RNA levels, but does not affect viral entry, maturation and release. These results reveal an unforeseen function of Cav-1 in facilitating ZIKV replication, which provides new insights into the intricate interaction between Cav-1 and ZIKV and underscores Cav-1 as a potential candidate for anti-ZIKV approaches.


Assuntos
Caveolina 1 , RNA Viral , Replicação Viral , Infecção por Zika virus , Zika virus , Caveolina 1/metabolismo , Caveolina 1/genética , Zika virus/fisiologia , Zika virus/metabolismo , Humanos , Infecção por Zika virus/virologia , Infecção por Zika virus/metabolismo , RNA Viral/metabolismo , RNA Viral/genética , Animais , Interações Hospedeiro-Patógeno , Chlorocebus aethiops , Células Vero , Células HEK293 , Internalização do Vírus , Replicação do RNA
13.
EMBO Rep ; 2024 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-39375464

RESUMO

Innate immunity senses microbial ligands known as pathogen-associated molecular patterns (PAMPs). Except for nucleic acids, PAMPs are exceedingly taxa-specific, thus enabling pattern recognition receptors to detect cognate pathogens while ignoring others. How the E3 ubiquitin ligase RNF213 can respond to phylogenetically distant pathogens, including Gram-negative Salmonella, Gram-positive Listeria, and eukaryotic Toxoplasma, remains unknown. Here we report that the evolutionary history of RNF213 is indicative of repeated adaptation to diverse pathogen target structures, especially in and around its newly identified CBM20 carbohydrate-binding domain, which we have resolved by cryo-EM. We find that RNF213 forms coats on phylogenetically distant pathogens. ATP hydrolysis by RNF213's dynein-like domain is essential for coat formation on all three pathogens studied as is RZ finger-mediated E3 ligase activity for bacteria. Coat formation is not diffusion-limited but instead relies on rate-limiting initiation events and subsequent cooperative incorporation of further RNF213 molecules. We conclude that RNF213 responds to evolutionarily distant pathogens through enzymatically amplified cooperative recruitment.

14.
Mol Cell ; 71(4): 637-648.e5, 2018 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-30118682

RESUMO

Although macrophages are armed with potent antibacterial functions, Mycobacterium tuberculosis (Mtb) replicates inside these innate immune cells. Determinants of macrophage intrinsic bacterial control, and the Mtb strategies to overcome them, are poorly understood. To further study these processes, we used an affinity tag purification mass spectrometry (AP-MS) approach to identify 187 Mtb-human protein-protein interactions (PPIs) involving 34 secreted Mtb proteins. This interaction map revealed two factors involved in Mtb pathogenesis-the secreted Mtb protein, LpqN, and its binding partner, the human ubiquitin ligase CBL. We discovered that an lpqN Mtb mutant is attenuated in macrophages, but growth is restored when CBL is removed. Conversely, Cbl-/- macrophages are resistant to viral infection, indicating that CBL regulates cell-intrinsic polarization between antibacterial and antiviral immunity. Collectively, these findings illustrate the utility of this Mtb-human PPI map for developing a deeper understanding of the intricate interactions between Mtb and its host.


Assuntos
Proteínas de Bactérias/genética , HIV/genética , Interações Hospedeiro-Patógeno , Mycobacterium tuberculosis/genética , Proteínas Proto-Oncogênicas c-cbl/genética , Fatores de Virulência/genética , Animais , Proteínas de Bactérias/imunologia , Linhagem Celular Tumoral , Chlamydia trachomatis/genética , Chlamydia trachomatis/imunologia , Regulação da Expressão Gênica , HIV/imunologia , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/imunologia , Humanos , Linfócitos/microbiologia , Linfócitos/virologia , Macrófagos/microbiologia , Macrófagos/virologia , Camundongos , Mycobacterium tuberculosis/imunologia , Cultura Primária de Células , Ligação Proteica , Mapeamento de Interação de Proteínas , Proteínas Proto-Oncogênicas c-cbl/deficiência , Proteínas Proto-Oncogênicas c-cbl/imunologia , Células RAW 264.7 , Transdução de Sinais , Fatores de Virulência/imunologia
15.
Proc Natl Acad Sci U S A ; 120(28): e2218812120, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37399397

RESUMO

Encounters between host cells and intracellular bacterial pathogens lead to complex phenotypes that determine the outcome of infection. Single-cell RNA sequencing (scRNA-seq) is increasingly used to study the host factors underlying diverse cellular phenotypes but has limited capacity to analyze the role of bacterial factors. Here, we developed scPAIR-seq, a single-cell approach to analyze infection with a pooled library of multiplex-tagged, barcoded bacterial mutants. Infected host cells and barcodes of intracellular bacterial mutants are both captured by scRNA-seq to functionally analyze mutant-dependent changes in host transcriptomes. We applied scPAIR-seq to macrophages infected with a library of Salmonella Typhimurium secretion system effector mutants. We analyzed redundancy between effectors and mutant-specific unique fingerprints and mapped the global virulence network of each individual effector by its impact on host immune pathways. ScPAIR-seq is a powerful tool to untangle bacterial virulence strategies and their complex interplay with host defense strategies that drive infection outcome.


Assuntos
Macrófagos , Salmonella typhimurium , Virulência/genética , Macrófagos/metabolismo , Fatores de Virulência/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Interações Hospedeiro-Patógeno/genética
16.
Proc Natl Acad Sci U S A ; 120(35): e2301045120, 2023 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-37607229

RESUMO

Subverting the host immune system is a major task for any given pathogen to assure its survival and proliferation. For the opportunistic human pathogen Bacillus cereus (Bc), immune evasion enables the establishment of potent infections. In various species of the Bc group, the pleiotropic regulator PlcR and its cognate cell-cell signaling peptide PapR7 regulate virulence gene expression in response to fluctuations in population density, i.e., a quorum-sensing (QS) system. However, how QS exerts its effects during infections and whether PlcR confers the immune evading ability remain unclear. Herein, we report how interception of the QS communication in Bc obliterates the ability to affect the host immune system. Here, we designed a peptide-based QS inhibitor that suppresses PlcR-dependent virulence factor expression and attenuates Bc infectivity in mouse models. We demonstrate that the QS peptidic inhibitor blocks host immune system-mediated eradication by reducing the expression of PlcR-regulated major toxins similarly to the profile that was observed for isogenic strains. Our findings provide evidence that Bc infectivity is regulated by QS circuit-mediated destruction of host immunity, thus reveal a interesting strategy to limit Bc virulence and enhance host defense. This peptidic quorum-quenching agent constitutes a readily accessible chemical tool for studying how other pathogen QS systems modulate host immunity and forms a basis for development of anti-infective therapeutics.


Assuntos
Bacillus , Percepção de Quorum , Humanos , Animais , Camundongos , Comunicação Celular , Bacillus cereus , Sistema Imunitário , Peptídeos/farmacologia
17.
Proc Natl Acad Sci U S A ; 120(13): e2213584120, 2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-36943879

RESUMO

Virtually all living cells are encased in glycans. They perform key cellular functions such as immunomodulation and cell-cell recognition. Yet, how their composition and configuration affect their functions remains enigmatic. Here, we constructed isogenic capsule-switch mutants harboring 84 types of capsular polysaccharides (CPSs) in Streptococcus pneumoniae. This collection enables us to systematically measure the affinity of structurally related CPSs to primary human nasal and bronchial epithelial cells. Contrary to the paradigm, the surface charge does not appreciably affect epithelial cell binding. Factors that affect adhesion to respiratory cells include the number of rhamnose residues and the presence of human-like glycomotifs in CPS. Besides, pneumococcal colonization stimulated the production of interleukin 6 (IL-6), granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractantprotein-1 (MCP-1) in nasal epithelial cells, which also appears to be dependent on the serotype. Together, our results reveal glycomotifs of surface polysaccharides that are likely to be important for colonization and survival in the human airway.


Assuntos
Células Epiteliais , Streptococcus pneumoniae , Humanos , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/metabolismo , Sistema Respiratório , Polissacarídeos/metabolismo , Nariz
18.
Semin Cell Dev Biol ; 146: 31-39, 2023 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-36682929

RESUMO

Transfer RNAs (tRNAs) are at the heart of the molecular biology central dogma, functioning to decode messenger RNAs into proteins. As obligate intracellular parasites, viruses depend on the host translation machinery, including host tRNAs. Thus, the ability of a virus to fine-tune tRNA expression elicits the power to impact the outcome of infection. DNA viruses commonly upregulate the output of RNA polymerase III (Pol III)-dependent transcripts, including tRNAs. Decades after these initial discoveries we know very little about how mature tRNA pools change during viral infection, as tRNA sequencing methodology has only recently reached proficiency. Here, we review perturbation of tRNA biogenesis by DNA virus infection, including an emerging player called tRNA-derived fragments (tRFs). We discuss how tRNA dysregulation shifts the power landscape between the host and virus, highlighting the potential for tRNA-based antivirals as a future therapeutic.


Assuntos
Infecções por Vírus de DNA , RNA de Transferência , Humanos , RNA de Transferência/genética , RNA de Transferência/metabolismo , RNA Mensageiro , Biologia
19.
J Biol Chem ; 300(5): 107286, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38636657

RESUMO

Hepatitis C virus (HCV) infection is tightly connected to the lipid metabolism with lipid droplets (LDs) serving as assembly sites for progeny virions. A previous LD proteome analysis identified annexin A3 (ANXA3) as an important HCV host factor that is enriched at LDs in infected cells and required for HCV morphogenesis. To further characterize ANXA3 function in HCV, we performed proximity labeling using ANXA3-BioID2 as bait in HCV-infected cells. Two of the top proteins identified proximal to ANXA3 during HCV infection were the La-related protein 1 (LARP1) and the ADP ribosylation factor-like protein 8B (ARL8B), both of which have been previously described to act in HCV particle production. In follow-up experiments, ARL8B functioned as a pro-viral HCV host factor without localizing to LDs and thus likely independent of ANXA3. In contrast, LARP1 interacts with HCV core protein in an RNA-dependent manner and is translocated to LDs by core protein. Knockdown of LARP1 decreased HCV spreading without altering HCV RNA replication or viral titers. Unexpectedly, entry of HCV particles and E1/E2-pseudotyped lentiviral particles was reduced by LARP1 depletion, whereas particle production was not altered. Using a recombinant vesicular stomatitis virus (VSV)ΔG entry assay, we showed that LARP1 depletion also decreased entry of VSV with VSV, MERS, and CHIKV glycoproteins. Therefore, our data expand the role of LARP1 as an HCV host factor that is most prominently involved in the early steps of infection, likely contributing to endocytosis of viral particles through the pleiotropic effect LARP1 has on the cellular translatome.


Assuntos
Anexina A3 , Hepacivirus , Hepatite C , Antígeno SS-B , Internalização do Vírus , Humanos , Anexina A3/metabolismo , Anexina A3/genética , Autoantígenos/metabolismo , Autoantígenos/genética , Células HEK293 , Hepacivirus/metabolismo , Hepacivirus/fisiologia , Hepatite C/metabolismo , Hepatite C/virologia , Hepatite C/genética , Interações Hospedeiro-Patógeno , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/virologia , Ribonucleoproteínas/metabolismo , Ribonucleoproteínas/genética , Proteínas do Core Viral/metabolismo , Proteínas do Core Viral/genética , Proteínas do Envelope Viral/metabolismo , Proteínas do Envelope Viral/genética
20.
J Biol Chem ; 300(3): 105710, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38309504

RESUMO

The bacterial envelope is an essential compartment involved in metabolism and metabolites transport, virulence, and stress defense. Its roles become more evident when homeostasis is challenged during host-pathogen interactions. In particular, the presence of free radical groups and excess copper in the periplasm causes noxious reactions, such as sulfhydryl group oxidation leading to enzymatic inactivation and protein denaturation. In response to this, canonical and accessory oxidoreductase systems are induced, performing quality control of thiol groups, and therefore contributing to restoring homeostasis and preserving survival under these conditions. Here, we examine recent advances in the characterization of the Dsb-like, Salmonella-specific Scs system. This system includes the ScsC/ScsB pair of Cu+-binding proteins with thiol-oxidoreductase activity, an alternative ScsB-partner, the membrane-linked ScsD, and a likely associated protein, ScsA, with a role in peroxide resistance. We discuss the acquisition of the scsABCD locus and its integration into a global regulatory pathway directing envelope response to Cu stress during the evolution of pathogens that also harbor the canonical Dsb systems. The evidence suggests that the canonical Dsb systems cannot satisfy the extra demands that the host-pathogen interface imposes to preserve functional thiol groups. This resulted in the acquisition of the Scs system by Salmonella. We propose that the ScsABCD complex evolved to connect Cu and redox stress responses in this pathogen as well as in other bacterial pathogens.


Assuntos
Proteínas de Bactérias , Proteínas de Transporte , Cobre , Salmonella , Proteínas de Bactérias/metabolismo , Cobre/metabolismo , Homeostase , Oxirredução , Oxirredutases/metabolismo , Salmonella/metabolismo , Compostos de Sulfidrila , Proteínas de Transporte/metabolismo
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