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1.
Cell ; 184(2): 460-475.e21, 2021 01 21.
Artículo en Inglés | MEDLINE | ID: mdl-33278358

RESUMEN

SARS-CoV-2-induced hypercytokinemia and inflammation are critically associated with COVID-19 severity. Baricitinib, a clinically approved JAK1/JAK2 inhibitor, is currently being investigated in COVID-19 clinical trials. Here, we investigated the immunologic and virologic efficacy of baricitinib in a rhesus macaque model of SARS-CoV-2 infection. Viral shedding measured from nasal and throat swabs, bronchoalveolar lavages, and tissues was not reduced with baricitinib. Type I interferon (IFN) antiviral responses and SARS-CoV-2-specific T cell responses remained similar between the two groups. Animals treated with baricitinib showed reduced inflammation, decreased lung infiltration of inflammatory cells, reduced NETosis activity, and more limited lung pathology. Importantly, baricitinib-treated animals had a rapid and remarkably potent suppression of lung macrophage production of cytokines and chemokines responsible for inflammation and neutrophil recruitment. These data support a beneficial role for, and elucidate the immunological mechanisms underlying, the use of baricitinib as a frontline treatment for inflammation induced by SARS-CoV-2 infection.


Asunto(s)
Antiinflamatorios/administración & dosificación , Azetidinas/administración & dosificación , Tratamiento Farmacológico de COVID-19 , COVID-19/inmunología , Macaca mulatta , Infiltración Neutrófila/efectos de los fármacos , Purinas/administración & dosificación , Pirazoles/administración & dosificación , Sulfonamidas/administración & dosificación , Animales , COVID-19/fisiopatología , Muerte Celular/efectos de los fármacos , Degranulación de la Célula/efectos de los fármacos , Modelos Animales de Enfermedad , Inflamación/tratamiento farmacológico , Inflamación/genética , Inflamación/inmunología , Quinasas Janus/antagonistas & inhibidores , Pulmón/efectos de los fármacos , Pulmón/inmunología , Pulmón/patología , Activación de Linfocitos/efectos de los fármacos , Macrófagos Alveolares/inmunología , SARS-CoV-2/fisiología , Índice de Severidad de la Enfermedad , Linfocitos T/inmunología , Replicación Viral/efectos de los fármacos
2.
Cell ; 177(5): 1153-1171.e28, 2019 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-31080066

RESUMEN

Conventional immunization strategies will likely be insufficient for the development of a broadly neutralizing antibody (bnAb) vaccine for HIV or other difficult pathogens because of the immunological hurdles posed, including B cell immunodominance and germinal center (GC) quantity and quality. We found that two independent methods of slow delivery immunization of rhesus monkeys (RMs) resulted in more robust T follicular helper (TFH) cell responses and GC B cells with improved Env-binding, tracked by longitudinal fine needle aspirates. Improved GCs correlated with the development of >20-fold higher titers of autologous nAbs. Using a new RM genomic immunoglobulin locus reference, we identified differential IgV gene use between immunization modalities. Ab mapping demonstrated targeting of immunodominant non-neutralizing epitopes by conventional bolus-immunized animals, whereas slow delivery-immunized animals targeted a more diverse set of epitopes. Thus, alternative immunization strategies can enhance nAb development by altering GCs and modulating the immunodominance of non-neutralizing epitopes.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , Linfocitos B/inmunología , Centro Germinal/inmunología , Anticuerpos Anti-VIH/inmunología , VIH-1/inmunología , Inmunización Pasiva , Linfocitos T Colaboradores-Inductores/inmunología , Animales , Linfocitos B/patología , Femenino , Centro Germinal/patología , Centro Germinal/virología , Macaca mulatta , Masculino , Linfocitos T Colaboradores-Inductores/patología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología
3.
Immunity ; 54(3): 542-556.e9, 2021 03 09.
Artículo en Inglés | MEDLINE | ID: mdl-33631118

RESUMEN

A combination of vaccination approaches will likely be necessary to fully control the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Here, we show that modified vaccinia Ankara (MVA) vectors expressing membrane-anchored pre-fusion stabilized spike (MVA/S) but not secreted S1 induced strong neutralizing antibody responses against SARS-CoV-2 in mice. In macaques, the MVA/S vaccination induced strong neutralizing antibodies and CD8+ T cell responses, and conferred protection from SARS-CoV-2 infection and virus replication in the lungs as early as day 2 following intranasal and intratracheal challenge. Single-cell RNA sequencing analysis of lung cells on day 4 after infection revealed that MVA/S vaccination also protected macaques from infection-induced inflammation and B cell abnormalities and lowered induction of interferon-stimulated genes. These results demonstrate that MVA/S vaccination induces neutralizing antibodies and CD8+ T cells in the blood and lungs and is a potential vaccine candidate for SARS-CoV-2.


Asunto(s)
Vacunas contra la COVID-19/inmunología , COVID-19/prevención & control , Vectores Genéticos/genética , SARS-CoV-2/inmunología , Vacunas de ADN/inmunología , Virus Vaccinia/genética , Animales , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Antígenos Virales/genética , Antígenos Virales/inmunología , COVID-19/inmunología , COVID-19/patología , COVID-19/virología , Vacunas contra la COVID-19/genética , Modelos Animales de Enfermedad , Expresión Génica , Orden Génico , Inmunofenotipificación , Pulmón/inmunología , Pulmón/patología , Pulmón/virología , Macaca , Macrófagos Alveolares/inmunología , Macrófagos Alveolares/metabolismo , Macrófagos Alveolares/patología , Ratones , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Vacunación/métodos , Vacunas de ADN/genética
5.
PLoS Pathog ; 20(5): e1012223, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38739675

RESUMEN

Natural killer-like B (NKB) cells are unique innate immune cells expressing both natural killer (NK) and B cell receptors. As first responders to infection, they secrete IL-18 to induce a critical cascade of innate and adaptive immune cell infiltration and activation. However, limited research exists on the role of NKB cells in homeostasis and infection, largely due to incomplete and erroneous evaluations. To fill this knowledge gap, we investigated the expression of signaling and trafficking proteins, and the in situ localization and transcriptome of naïve NKB cells compared to conventionally-defined NK and B cells, as well as modulations of these cells in SIV infection. Intracellular signaling proteins and trafficking markers were expressed differentially on naïve NKB cells, with high expression of CD62L and Syk, and low expression of CD69, α4ß7, FcRg, Zap70, and CD3z, findings which were more similar to B cells than NK cells. CD20+NKG2a/c+ NKB cells were identified in spleen, mesenteric lymph nodes (MLN), colon, jejunum, and liver of naïve rhesus macaques (RM) via tissue imaging, with NKB cell counts concentrated in spleen and MLN. For the first time, single cell RNA sequencing (scRNAseq), including B cell receptor (BCR) sequencing, of sorted NKB cells confirmed that NKB cells are unique. Transcriptomic analysis of naïve splenic NKB cells by scRNAseq showed that NKB cells undergo somatic hypermutation and express Ig receptors, similar to B cells. While only 15% of sorted NKB cells showed transcript expression of both KLRC1 (NKG2A) and MS4A1 (CD20) genes, only 5% of cells expressed KLRC1, MS4A1, and IgH/IgL transcripts. We observed expanded NKB frequencies in RM gut and buccal mucosa as early as 14 and 35 days post-SIV infection, respectively. Further, mucosal and peripheral NKB cells were associated with colorectal cytokine milieu and oral microbiome changes, respectively. Our studies indicate that NKB cells gated on CD3-CD14-CD20+NKG2A/C+ cells were inclusive of transcriptomically conventional B and NK cells in addition to true NKB cells, confounding accurate phenotyping and frequency recordings that could only be resolved using genomic techniques. Although NKB cells were clearly elevated during SIV infection and associated with inflammatory changes during infection, further interrogation is necessary to acurately identify the true phenotype and significance of NKB cells in infection and inflammation.


Asunto(s)
Inmunidad Innata , Células Asesinas Naturales , Macaca mulatta , Síndrome de Inmunodeficiencia Adquirida del Simio , Virus de la Inmunodeficiencia de los Simios , Animales , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/inmunología , Células Asesinas Naturales/inmunología , Linfocitos B/inmunología
6.
Nature ; 578(7793): 160-165, 2020 02.
Artículo en Inglés | MEDLINE | ID: mdl-31969707

RESUMEN

Long-lasting, latently infected resting CD4+ T cells are the greatest obstacle to obtaining a cure for HIV infection, as these cells can persist despite decades of treatment with antiretroviral therapy (ART). Estimates indicate that more than 70 years of continuous, fully suppressive ART are needed to eliminate the HIV reservoir1. Alternatively, induction of HIV from its latent state could accelerate the decrease in the reservoir, thus reducing the time to eradication. Previous attempts to reactivate latent HIV in preclinical animal models and in clinical trials have measured HIV induction in the peripheral blood with minimal focus on tissue reservoirs and have had limited effect2-9. Here we show that activation of the non-canonical NF-κB signalling pathway by AZD5582 results in the induction of HIV and SIV RNA expression in the blood and tissues of ART-suppressed bone-marrow-liver-thymus (BLT) humanized mice and rhesus macaques infected with HIV and SIV, respectively. Analysis of resting CD4+ T cells from tissues after AZD5582 treatment revealed increased SIV RNA expression in the lymph nodes of macaques and robust induction of HIV in almost all tissues analysed in humanized mice, including the lymph nodes, thymus, bone marrow, liver and lung. This promising approach to latency reversal-in combination with appropriate tools for systemic clearance of persistent HIV infection-greatly increases opportunities for HIV eradication.


Asunto(s)
Infecciones por VIH/virología , VIH-1/fisiología , FN-kappa B/metabolismo , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/fisiología , Latencia del Virus , Alquinos/farmacología , Animales , Antirretrovirales/farmacología , Infecciones por VIH/metabolismo , VIH-1/efectos de los fármacos , Macaca mulatta , Ratones , Oligopéptidos/farmacología , Síndrome de Inmunodeficiencia Adquirida del Simio/metabolismo , Virus de la Inmunodeficiencia de los Simios/efectos de los fármacos , Latencia del Virus/efectos de los fármacos
7.
PLoS Pathog ; 19(10): e1011717, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37878666

RESUMEN

A protective HIV-1 vaccine has been hampered by a limited understanding of how B cells acquire neutralizing activity. Our previous vaccines expressing two different HIV-1 envelopes elicited robust antigen specific serum IgG titers in 20 rhesus macaques; yet serum from only two animals neutralized the autologous virus. Here, we used high throughput immunoglobulin receptor and single cell RNA sequencing to characterize the overall expansion, recall, and maturation of antigen specific B cells longitudinally over 90 weeks. Diversification and expansion of many B cell clonotypes occurred broadly in the absence of serum neutralization. However, in one animal that developed neutralization, two neutralizing B cell clonotypes arose from the same immunoglobulin germline and were tracked longitudinally. Early antibody variants with high identity to germline neutralized the autologous virus while later variants acquired somatic hypermutation and increased neutralization potency. The early engagement of precursors capable of neutralization with little to no SHM followed by prolonged affinity maturation allowed the two neutralizing lineages to successfully persist despite many other antigen specific B cells. The findings provide new insight into B cells responding to HIV-1 envelope during heterologous prime and boost immunization in rhesus macaques and the development of selected autologous neutralizing antibody lineages.


Asunto(s)
Vacunas contra el SIDA , Infecciones por VIH , Seropositividad para VIH , VIH-1 , Animales , Anticuerpos Neutralizantes , Macaca mulatta , Anticuerpos Anti-VIH , Inmunización , Productos del Gen env del Virus de la Inmunodeficiencia Humana
8.
PLoS Pathog ; 18(3): e1010395, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35271686

RESUMEN

Severe influenza kills tens of thousands of individuals each year, yet the mechanisms driving lethality in humans are poorly understood. Here we used a unique translational model of lethal H5N1 influenza in cynomolgus macaques that utilizes inhalation of small-particle virus aerosols to define mechanisms driving lethal disease. RNA sequencing of lung tissue revealed an intense interferon response within two days of infection that resulted in widespread expression of interferon-stimulated genes, including inflammatory cytokines and chemokines. Macaques with lethal disease had rapid and profound loss of alveolar macrophages (AMs) and infiltration of activated CCR2+ CX3CR1+ interstitial macrophages (IMs) and neutrophils into lungs. Parallel changes of AMs and neutrophils in bronchoalveolar lavage (BAL) correlated with virus load when compared to macaques with mild influenza. Both AMs and IMs in lethal influenza were M1-type inflammatory macrophages which expressed neutrophil chemotactic factors, while neutrophils expressed genes associated with activation and generation of neutrophil extracellular traps (NETs). NETs were prominent in lung and were found in alveolar spaces as well as lung parenchyma. Genes associated with pyroptosis but not apoptosis were increased in lung, and activated inflammatory caspases, IL-1ß and cleaved gasdermin D (GSDMD) were present in bronchoalveolar lavage fluid and lung homogenates. Cleaved GSDMD was expressed by lung macrophages and alveolar epithelial cells which were present in large numbers in alveolar spaces, consistent with loss of epithelial integrity. Cleaved GSDMD colocalized with viral NP-expressing cells in alveoli, reflecting pyroptosis of infected cells. These novel findings reveal that a potent interferon and inflammatory cascade in lung associated with infiltration of inflammatory macrophages and neutrophils, elaboration of NETs and cell death by pyroptosis mediates lethal H5N1 influenza in nonhuman primates, and by extension humans. These innate pathways represent promising therapeutic targets to prevent severe influenza and potentially other primary viral pneumonias in humans.


Asunto(s)
Subtipo H5N1 del Virus de la Influenza A , Infecciones por Orthomyxoviridae , Animales , Interferones/inmunología , Pulmón , Macrófagos Alveolares/inmunología , Neutrófilos/inmunología , Infecciones por Orthomyxoviridae/inmunología , Primates , Piroptosis
9.
PLoS Pathog ; 18(5): e1010488, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35503780

RESUMEN

Transmitted/founder (T/F) HIV-1 envelope proteins (Envs) from infected individuals that developed neutralization breadth are likely to possess inherent features desirable for vaccine immunogen design. To explore this premise, we conducted an immunization study in rhesus macaques (RM) using T/F Env sequences from two human subjects, one of whom developed potent and broad neutralizing antibodies (Z1800M) while the other developed little to no neutralizing antibody responses (R66M) during HIV-1 infection. Using a DNA/MVA/protein immunization protocol, 10 RM were immunized with each T/F Env. Within each T/F Env group, the protein boosts were administered as either monomeric gp120 or stabilized trimeric gp140 protein. All vaccination regimens elicited high titers of antigen-specific IgG, and two animals that received monomeric Z1800M Env gp120 developed autologous neutralizing activity. Using early Env escape variants isolated from subject Z1800M as guides, the serum neutralizing activity of the two immunized RM was found to be dependent on the gp120 V5 region. Interestingly, the exact same residues of V5 were also targeted by a neutralizing monoclonal antibody (nmAb) isolated from the subject Z1800M early in infection. Glycan profiling and computational modeling of the Z1800M Env gp120 immunogen provided further evidence that the V5 loop is exposed in this T/F Env and was a dominant feature that drove neutralizing antibody targeting during infection and immunization. An expanded B cell clonotype was isolated from one of the neutralization-positive RM and nmAbs corresponding to this group demonstrated V5-dependent neutralization similar to both the RM serum and the human Z1800M nmAb. The results demonstrate that neutralizing antibody responses elicited by the Z1800M T/F Env in RM converged with those in the HIV-1 infected human subject, illustrating the potential of using immunogens based on this or other T/F Envs with well-defined immunogenicity as a starting point to drive breadth.


Asunto(s)
Vacunas contra el SIDA , Infecciones por VIH , VIH-1 , Animales , Anticuerpos Neutralizantes , Anticuerpos Anti-VIH , Proteína gp120 de Envoltorio del VIH , Infecciones por VIH/prevención & control , Humanos , Macaca mulatta , Productos del Gen env del Virus de la Inmunodeficiencia Humana
10.
PLoS Pathog ; 17(6): e1009674, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-34181694

RESUMEN

HIV associated immune activation (IA) is associated with increased morbidity in people living with HIV (PLWH) on antiretroviral therapy, and remains a barrier for strategies aimed at reducing the HIV reservoir. The underlying mechanisms of IA have not been definitively elucidated, however, persistent production of Type I IFNs and expression of ISGs is considered to be one of the primary factors. Plasmacytoid DCs (pDCs) are a major producer of Type I IFN during viral infections, and are highly immunomodulatory in acute HIV and SIV infection, however their role in chronic HIV/SIV infection has not been firmly established. Here, we performed a detailed transcriptomic characterization of pDCs in chronic SIV infection in rhesus macaques, and in sooty mangabeys, a natural host non-human primate (NHP) species that undergoes non-pathogenic SIV infection. We also investigated the immunostimulatory capacity of lymph node homing pDCs in chronic SIV infection by contrasting gene expression of pDCs isolated from lymph nodes with those from blood. We observed that pDCs in LNs, but not blood, produced high levels of IFNα transcripts, and upregulated gene expression programs consistent with T cell activation and exhaustion. We apply a novel strategy to catalogue uncharacterized surface molecules on pDCs, and identified the lymphoid exhaustion markers TIGIT and LAIR1 as highly expressed in SIV infection. pDCs from SIV-infected sooty mangabeys lacked the activation profile of ISG signatures observed in infected macaques. These data demonstrate that pDCs are a primary producer of Type I IFN in chronic SIV infection. Further, this study demonstrated that pDCs trafficking to LNs persist in a highly activated state well into chronic infection. Collectively, these data identify pDCs as a highly immunomodulatory cell population in chronic SIV infection, and a putative therapeutic target to reduce immune activation.


Asunto(s)
Células Dendríticas/inmunología , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Animales , Cercocebus atys , Perfilación de la Expresión Génica , Macaca mulatta , RNA-Seq , Transcriptoma
11.
J Virol ; 94(19)2020 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-32699094

RESUMEN

The newly emerged human coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a pandemic of respiratory illness. Current evidence suggests that severe cases of SARS-CoV-2 are associated with a dysregulated immune response. However, little is known about how the innate immune system responds to SARS-CoV-2. In this study, we modeled SARS-CoV-2 infection using primary human airway epithelial (pHAE) cultures, which are maintained in an air-liquid interface. We found that SARS-CoV-2 infects and replicates in pHAE cultures and is directionally released on the apical, but not basolateral, surface. Transcriptional profiling studies found that infected pHAE cultures had a molecular signature dominated by proinflammatory cytokines and chemokine induction, including interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), and CXCL8, and identified NF-κB and ATF-4 as key drivers of this proinflammatory cytokine response. Surprisingly, we observed a complete lack of a type I or III interferon (IFN) response to SARS-CoV-2 infection. However, pretreatment and posttreatment with type I and III IFNs significantly reduced virus replication in pHAE cultures that correlated with upregulation of antiviral effector genes. Combined, our findings demonstrate that SARS-CoV-2 does not trigger an IFN response but is sensitive to the effects of type I and III IFNs. Our studies demonstrate the utility of pHAE cultures to model SARS-CoV-2 infection and that both type I and III IFNs can serve as therapeutic options to treat COVID-19 patients.IMPORTANCE The current pandemic of respiratory illness, COVID-19, is caused by a recently emerged coronavirus named SARS-CoV-2. This virus infects airway and lung cells causing fever, dry cough, and shortness of breath. Severe cases of COVID-19 can result in lung damage, low blood oxygen levels, and even death. As there are currently no vaccines approved for use in humans, studies of the mechanisms of SARS-CoV-2 infection are urgently needed. Our research identifies an excellent system to model SARS-CoV-2 infection of the human airways that can be used to test various treatments. Analysis of infection in this model system found that human airway epithelial cell cultures induce a strong proinflammatory cytokine response yet block the production of type I and III IFNs to SARS-CoV-2. However, treatment of airway cultures with the immune molecules type I or type III interferon (IFN) was able to inhibit SARS-CoV-2 infection. Thus, our model system identified type I or type III IFN as potential antiviral treatments for COVID-19 patients.


Asunto(s)
Betacoronavirus/inmunología , Infecciones por Coronavirus/inmunología , Células Epiteliales/inmunología , Interferón Tipo I/inmunología , Interferones/inmunología , Neumonía Viral/inmunología , Animales , Betacoronavirus/fisiología , Bronquios/citología , Bronquios/inmunología , Bronquios/virología , COVID-19 , Línea Celular , Células Cultivadas , Quimiocinas/inmunología , Chlorocebus aethiops , Infecciones por Coronavirus/virología , Citocinas/inmunología , Perros , Células Epiteliales/virología , Humanos , Pulmón/citología , Pulmón/inmunología , Pulmón/virología , Células de Riñón Canino Madin Darby , Pandemias , Neumonía Viral/virología , SARS-CoV-2 , Células Vero , Replicación Viral , Interferón lambda
12.
J Virol ; 93(6)2019 03 15.
Artículo en Inglés | MEDLINE | ID: mdl-30626670

RESUMEN

West Nile virus (WNV) is a neurotropic mosquito-borne flavivirus of global importance. Neuroinvasive WNV infection results in encephalitis and can lead to prolonged neurological impairment or death. Type I interferon (IFN-I) is crucial for promoting antiviral defenses through the induction of antiviral effectors, which function to restrict viral replication and spread. However, our understanding of the antiviral response to WNV infection is mostly derived from analysis of bulk cell populations. It is becoming increasingly apparent that substantial heterogeneity in cellular processes exists among individual cells, even within a seemingly homogenous cell population. Here, we present WNV-inclusive single-cell RNA sequencing (scRNA-seq), an approach to examine the transcriptional variation and viral RNA burden across single cells. We observed that only a few cells within the bulk population displayed robust transcription of IFN-ß mRNA, and this did not appear to depend on viral RNA abundance within the same cell. Furthermore, we observed considerable transcriptional heterogeneity in the IFN-I response, with genes displaying high unimodal and bimodal expression patterns. Broadly, IFN-stimulated genes negatively correlated with viral RNA abundance, corresponding with a precipitous decline in expression in cells with high viral RNA levels. Altogether, we demonstrated the feasibility and utility of WNV-inclusive scRNA-seq as a high-throughput technique for single-cell transcriptomics and WNV RNA detection. This approach can be implemented in other models to provide insights into the cellular features of protective immunity and identify novel therapeutic targets.IMPORTANCE West Nile virus (WNV) is a clinically relevant pathogen responsible for recurrent epidemics of neuroinvasive disease. Type I interferon is essential for promoting an antiviral response against WNV infection; however, it is unclear how heterogeneity in the antiviral response at the single-cell level impacts viral control. Specifically, conventional approaches lack the ability to distinguish differences across cells with varying viral abundance. The significance of our research is to demonstrate a new technique for studying WNV infection at the single-cell level. We discovered extensive variation in antiviral gene expression and viral abundance across cells. This protocol can be applied to primary cells or in vivo models to better understand the underlying cellular heterogeneity following WNV infection for the development of targeted therapeutic strategies.


Asunto(s)
Antivirales/farmacología , Interferón Tipo I/farmacología , Fiebre del Nilo Occidental/tratamiento farmacológico , Virus del Nilo Occidental/efectos de los fármacos , Animales , Línea Celular , Culicidae/virología , Ratones , ARN Viral/genética , Análisis de Secuencia de ARN/métodos , Análisis de la Célula Individual/métodos , Replicación Viral/efectos de los fármacos , Fiebre del Nilo Occidental/virología , Virus del Nilo Occidental/genética
13.
J Bacteriol ; 199(18)2017 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-28484044

RESUMEN

Histidine kinases are key components of regulatory systems that enable bacteria to respond to environmental changes. Two major classes of histidine kinases are recognized on the basis of their modular design: classical (HKI) and chemotaxis specific (HKII). Recently, a new type of histidine kinase that appeared to have features of both HKIs and HKIIs was identified and termed HKIII; however, the details of HKIII's relationship to other two classes of histidine kinases, their function, and evolutionary history remain unknown. Here, we carried out genomic, phylogenetic, and protein sequence analyses that allowed us to reveal the unusual evolutionary history of this protein family, formalize its distinctive features, and propose its putative function. HKIIIs are characterized by the presence of sensory domains and the lack of a dimerization domain, which is typically present in all histidine kinases. In addition to a single-domain response regulator, HKIII signal transduction systems utilize CheX phosphatase and, in many instances, an unorthodox soluble chemoreceptor that are usual components of chemotaxis signal transduction systems. However, many HKIII genes are found in genomes completely lacking chemotaxis genes, thus decoupling their function from chemotaxis. By contrast, all HKIII-containing genomes also contain pilT, a marker gene for bacterial type IV pilus-based motility, whose regulation is proposed as a putative function for HKIII. These signal transduction systems have a narrow phyletic distribution but are present in many emerging and opportunistic pathogens, thus offering an attractive potential target for future antimicrobial drug design.IMPORTANCE Bacteria adapt to their environment and their hosts by detecting signals and regulating their cellular functions accordingly. Here, we describe a largely unexplored family of signal transduction histidine kinases, called HKIII, that have a unique modular design. While they are currently identified in a relatively short list of bacterial species, this list contains many emerging pathogens. We show that HKIIIs likely control bacterial motility across solid surfaces, which is a key virulence factor in many bacteria, including those causing severe infections. Full understanding of this putative function may help in designing effective drugs against pathogens that will not affect the majority of the beneficial human microbiome.


Asunto(s)
Histidina Quinasa/metabolismo , Locomoción , Transducción de Señal , Sistemas de Secreción Tipo IV/metabolismo , Biología Computacional , Histidina Quinasa/genética , Filogenia , Dominios Proteicos , Homología de Secuencia de Aminoácido
14.
PLoS Comput Biol ; 12(4): e1004862, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27049771

RESUMEN

Cellular receptors usually contain a designated sensory domain that recognizes the signal. Per/Arnt/Sim (PAS) domains are ubiquitous sensors in thousands of species ranging from bacteria to humans. Although PAS domains were described as intracellular sensors, recent structural studies revealed PAS-like domains in extracytoplasmic regions in several transmembrane receptors. However, these structurally defined extracellular PAS-like domains do not match sequence-derived PAS domain models, and thus their distribution across the genomic landscape remains largely unknown. Here we show that structurally defined extracellular PAS-like domains belong to the Cache superfamily, which is homologous to, but distinct from the PAS superfamily. Our newly built computational models enabled identification of Cache domains in tens of thousands of signal transduction proteins including those from important pathogens and model organisms. Furthermore, we show that Cache domains comprise the dominant mode of extracellular sensing in prokaryotes.


Asunto(s)
Proteínas Arqueales/química , Proteínas Bacterianas/química , Estructura Terciaria de Proteína , Receptores de Superficie Celular/química , Algoritmos , Proteínas Arqueales/genética , Proteínas Bacterianas/genética , Biología Computacional , Evolución Molecular , Cadenas de Markov , Modelos Moleculares , Filogenia , Células Procariotas/química , Estructura Terciaria de Proteína/genética , Receptores de Superficie Celular/genética , Transducción de Señal
15.
Biochemistry ; 55(43): 6056-6069, 2016 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-27753291

RESUMEN

The dynamics of anion-quadrupole (or anion-π) interactions formed between negatively charged (Asp/Glu) and aromatic (Phe) side chains are for the first time computationally characterized in RmlC (Protein Data Bank entry 1EP0 ), a homodimeric epimerase. Empirical force field-based molecular dynamics simulations predict anion-quadrupole pairs and triplets (anion-anion-π and anion-π-π) are formed by the protein during the simulated trajectory, which suggests that the anion-quadrupole interactions may provide a significant contribution to the overall stability of the protein, with an average of -1.6 kcal/mol per pair. Some anion-π interactions are predicted to form during the trajectory, extending the number of anion-quadrupole interactions beyond those predicted from crystal structure analysis. At the same time, some anion-π pairs observed in the crystal structure exhibit marginal stability. Overall, most anion-π interactions alternate between an "on" state, with significantly stabilizing energies, and an "off" state, with marginal or null stabilizing energies. The way proteins possibly compensate for transient loss of anion-quadrupole interactions is characterized in the RmlC aspartate 84-phenylalanine 112 anion-quadrupole pair observed in the crystal structure. A double-mutant cycle analysis of the thermal stability suggests a possible loss of anion-π interactions compensated by variations of hydration of the residues and formation of compensating electrostatic interactions. These results suggest that near-planar anion-quadrupole pairs can exist, sometimes transiently, which may play a role in maintaining the structural stability and function of the protein, in an otherwise very dynamic interplay of a nonbonded interaction network as well as solvent effects.


Asunto(s)
Proteínas/química , Aniones , Simulación de Dinámica Molecular , Teoría Cuántica
16.
Eur J Pediatr ; 175(2): 171-9, 2016 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-26286814

RESUMEN

This study was conducted at a tertiary care center in northern India to evaluate the validity of non-invasive transcutaneous hemoglobin estimation in healthy and sick children in comparison to hemoglobin estimation by traditional lab method. A method comparison study was conducted including 150 subjects. Enrolled patients included 80 neonates with average age of 3.9 ± 2.1 days, and 70 children with average age of 5.8 ± 2 years. Each population (newborn and children) comprised of almost equal numbers of healthy and critically ill patients with shock. Hemoglobin (Hb) was estimated on enrolment by transcutaneous spectrophotometry (SpHb) and traditional automated lab analyzer (Hb-Lab). Difference between Hb levels by the two methods (called bias) was measured and analyzed using Bland-Altman method. Out of 148 data pairs analyzed, bias between SpHb and Hb-Lab was -1.52 ± 1.91 g/dl (mean ± SD). SpHb showed excellent positive correlation with Hb-Lab (r = 0.94 (p < 0.001)) and good visual agreement on Bland-Altman plots. Bias was higher in sick subjects with shock as compared to healthy ones in both neonatal and pediatric population (-2.31 ± 2.21 g/dl versus -0.77 ± 1.2 g/dl, respectively). CONCLUSIONS: SpHb showed good accuracy and correlated well with lab estimated Hb levels in healthy children. However, in children with impaired peripheral perfusion, its diagnostic accuracy was inadequate to justify routine use for quantification of severity of anemia and making transfusion decisions solely on non-invasive estimation of hemoglobin. WHAT IS KNOWN: Non-invasive hemoglobin estimation is a relatively new and novel method which has given mixed results regarding its potential efficacy in adults. There is limited data regarding usefulness and accuracy of non-invasive Hb estimation by SpHb in sick neonates and children. WHAT IS NEW: Non-invasive Hb estimation by SpHb monitor is reasonably accurate in healthy neonates and children. It can be used in critically ill children and neonates, but in conjunction with lab confirmation of Hb values.


Asunto(s)
Enfermedad Crítica , Hemoglobinometría/métodos , Hemoglobinas/análisis , Oximetría/métodos , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Unidades de Cuidados Intensivos , Masculino , Sistemas de Atención de Punto , Estudios Prospectivos , Reproducibilidad de los Resultados
17.
Acta Paediatr ; 105(11): e526-e530, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27564579

RESUMEN

AIM: Placental redistribution has been shown to improve haematological outcomes in the immediate neonatal period and early infancy. This study compared the effects of delayed cord clamping (DCC) and umbilical cord milking (UCM) on haematological and growth parameters at 12 months of age. METHODS: This was a follow-up study of a randomised control trial, conducted in a tertiary care paediatric centre from August 2013 to August 2014. We studied 200 apparently healthy Indian infants randomised at birth to receive DCC for 60-90 seconds or UCM. The outcome measures were iron status and physical growth parameters at 12 months. RESULTS: Of the 200 babies, 161 completed the follow-up and baseline characteristics were comparable in both groups. The mean haemoglobin in the DCC group (102.2 (17.2) g/L and serum ferritin 16.44 (2.77) µg/L) showed no significant differences to the UCM group (98.6 (17.1) g/L and 18.2 (2.8) µg/L) at one year. In addition, there were no significant differences in weight, height and mid-upper arm circumference in the two groups. CONCLUSION: Term-born Indian infants who had DCC at 60-90 seconds or UCM showed no significant differences in ferritin and haemoglobin levels and growth parameters at 12 months of age.


Asunto(s)
Anemia Ferropénica/prevención & control , Ferritinas/sangre , Hematócrito , Hemoglobinas/análisis , Circulación Placentaria/fisiología , Cordón Umbilical , Constricción , Femenino , Estudios de Seguimiento , Humanos , India , Recién Nacido , Modelos Logísticos , Embarazo , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Tiempo
18.
Eur J Pediatr ; 174(9): 1159-67, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25800496

RESUMEN

The objective of the study was to compare the effect of umbilical cord milking (UCM) and delayed cord clamping (DCC) on hematological parameters (serum ferritin and hemoglobin) at 6 weeks of life in term neonates. It was a randomized controlled trail conducted at a teaching hospital in North India during August 2012 to August 2013. Babies born at >36 weeks of gestation were randomized in two groups, UCM and DCC (100 in each group). Umbilical cord milking was done after cutting and clamping the cord at 25 cm from the umbilicus. In DCC group, clamping was delayed by 60 to 90 s before cutting the cord. The baseline characteristics were comparable in the two groups. Mean serum ferritin (134.0 ng/ml [89.8]) and mean hemoglobin (11.0 gm/dl [2.4]) in umbilical cord milking group was comparable to mean serum ferritin (142.7 ng/ml [87.1]) and hemoglobin (11.3 gm/dl [2.6]) in DCC group at 6 weeks of age. There was no difference in hemodynamic status, cranial Doppler indices, and adverse neonatal outcomes among the two groups. CONCLUSION: In term neonates, the DCC and UCM had comparable effect on hematological parameters at 6 weeks of life. WHAT IS KNOWN: • Delayed cord blood clamping improves certain hematologic parameters for neonates, which is potentially important in populations with high rates of neonatal and childhood anemia, but that delayed cord blood clamping may not be feasible in clinical situations when neonatal resuscitation is urgent. WHAT IS NEW: • There is no significant difference in ferritin and hemoglobin levels at 6 weeks among term, Indian neonates who had UCM and DCC and that this study may give support to the practice of UCM in term deliveries when DCC is not feasible.


Asunto(s)
Anemia/prevención & control , Ferritinas/sangre , Sangre Fetal/trasplante , Hemoglobinas/análisis , Recien Nacido Prematuro , Cordón Umbilical/cirugía , Anemia/sangre , Constricción , Femenino , Estudios de Seguimiento , Hematócrito , Humanos , Recién Nacido , Recien Nacido Prematuro/sangre , Masculino , Placenta , Embarazo , Factores de Tiempo
19.
Indian J Med Res ; 139(3): 379-85, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24820831

RESUMEN

BACKGROUND & OBJECTIVES: Randomized controlled trials in developed countries have reported benefits of Lactobacillus GG (LGG) in the treatment of acute watery diarrhoea, but there is paucity of such data from India. The study was aimed to evaluate the efficacy and safety of Lactobacillus GG in the treatment of acute diarrhoea in children from a semi-urban city in north India. METHODS: In this open labelled, randomized controlled trial 2000 children with acute watery diarrhoea, aged between 6 months to 5 years visiting outpatient department and emergency room of a teaching hospital in north India were enrolled. The children were randomized into receiving either Lactobacillus GG in dose of 10 billion cfu/day for five days or no probiotic medication in addition to standard WHO management of diarrhoea. Primary outcomes were duration of diarrhoea and time to change in consistency of stools. RESULTS: Median (inter quartile range) duration of diarrhoea was significantly shorter in children in LGG group [60 (54-72) h vs. 78 (72-90) h; P<0.001]. Also, there was faster improvement in stool consistency in children receiving Lactobacillus GG than control group [36 (30-36) h vs. 42 (36-48) h; P<0.001]. There was significant reduction in average number of stools per day in LGG group (P<0.001) compared to the control group. These benefits were seen irrespective of rotavirus positivity in stool tests. INTERPRETATION & CONCLUSIONS: Our results showed that the use of Lactobacillus GG in children with acute diarrhoea resulted in shorter duration and faster improvement in stool consistency as compared to the control group.


Asunto(s)
Diarrea/tratamiento farmacológico , Lactobacillus , Probióticos/uso terapéutico , Preescolar , Ensayo de Inmunoadsorción Enzimática , Humanos , India , Lactante , Probióticos/administración & dosificación , Factores de Tiempo , Resultado del Tratamiento
20.
J Phys Chem B ; 128(17): 4047-4052, 2024 May 02.
Artículo en Inglés | MEDLINE | ID: mdl-38652834

RESUMEN

Electronic excitation transfer dynamics in photosynthetic systems, including the Fenna-Matthews-Olson complex, are often modeled using the interaction picture of three two-level systems, also known as the 3-site system. Among the two possible configurations, uphill and downhill, a recent publication reported an intriguing correlation between population dynamics and the intersite coupling. Specifically, the uphill configuration has been shown to have a pronounced dependence on perturbations in the intersite coupling, whereas the downhill configuration displays negligible dependence. In this study, we consider a generic 3-site configuration and model site interactions through the Markovian master equation. Through this approach, we derive succinct analytical expressions for the population dynamics between the sites, shedding light on the differences in behavior between the two configurations. Using these analytical expressions, we demonstrate the range of tunability in population dynamics achievable with minimal changes in intersite coupling, and we validate these findings through simulation results. These insights into the population dynamics of a 3-site system are expected to play a crucial role in facilitating the design of efficient energy-transfer pathways in molecular systems.

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