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Ribonuclease (RNase) P is a ubiquitous ribozyme that cleaves the 5' leader from precursor tRNAs. Here, we report cryo-electron microscopy structures of the human nuclear RNase P alone and in complex with tRNAVal. Human RNase P is a large ribonucleoprotein complex that contains 10 protein components and one catalytic RNA. The protein components form an interlocked clamp that stabilizes the RNA in a conformation optimal for substrate binding. Human RNase P recognizes the tRNA using a double-anchor mechanism through both protein-RNA and RNA-RNA interactions. Structural comparison of the apo and tRNA-bound human RNase P reveals that binding of tRNA induces a local conformational change in the catalytic center, transforming the ribozyme into an active state. Our results also provide an evolutionary model depicting how auxiliary RNA elements in bacterial RNase P, essential for substrate binding, and catalysis, were replaced by the much more complex and multifunctional protein components in higher organisms.
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Microscopía por Crioelectrón , ARN de Transferencia/química , Ribonucleasa P/química , Sitios de Unión , Evolución Molecular , Células HEK293 , Holoenzimas/química , Humanos , Simulación de Dinámica Molecular , Conformación de Ácido Nucleico , Dominios Proteicos , Estructura Terciaria de Proteína , ARN de Transferencia/metabolismo , Ribonucleasa P/aislamiento & purificación , Ribonucleasa P/metabolismoRESUMEN
Understanding resistance to antibody to programmed cell death protein 1 (PD-1; anti-PD-1) is crucial for the development of reversal strategies. In anti-PD-1-resistant models, simultaneous anti-PD-1 and vaccine therapy reversed resistance, while PD-1 blockade before antigen priming abolished therapeutic outcomes. This was due to induction of dysfunctional PD-1+CD38hi CD8+ cells by PD-1 blockade in suboptimally primed CD8 cell conditions induced by tumors. This results in erroneous T cell receptor signaling and unresponsiveness to antigenic restimulation. On the other hand, PD-1 blockade of optimally primed CD8 cells prevented the induction of dysfunctional CD8 cells, reversing resistance. Depleting PD-1+CD38hi CD8+ cells enhanced therapeutic outcomes. Furthermore, non-responding patients showed more PD-1+CD38+CD8+ cells in tumor and blood than responders. In conclusion, the status of CD8+ T cell priming is a major contributor to anti-PD-1 therapeutic resistance. PD-1 blockade in unprimed or suboptimally primed CD8 cells induces resistance through the induction of PD-1+CD38hi CD8+ cells that is reversed by optimal priming. PD-1+CD38hi CD8+ cells serve as a predictive and therapeutic biomarker for anti-PD-1 treatment. Sequencing of anti-PD-1 and vaccine is crucial for successful therapy.
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ADP-Ribosil Ciclasa 1/metabolismo , Linfocitos T CD8-positivos/inmunología , Resistencia a Antineoplásicos/inmunología , Glicoproteínas de Membrana/metabolismo , Neoplasias/inmunología , Receptor de Muerte Celular Programada 1/inmunología , ADP-Ribosil Ciclasa 1/genética , Animales , Anticuerpos/inmunología , Linfocitos T CD8-positivos/patología , Vacunas contra el Cáncer/inmunología , Línea Celular Tumoral , Resistencia a Antineoplásicos/genética , Femenino , Humanos , Inmunoterapia/métodos , Glicoproteínas de Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Ratones Transgénicos , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Microambiente Tumoral/inmunologíaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Protein lipoylation, a crucial post-translational modification (PTM), plays a pivotal role in mitochondrial function and emerges as a key player in cell death through cuproptosis. This novel copper-driven cell death pathway is activated by excessive copper ions binding to lipoylated mitochondrial proteins, disrupting energy production and causing lethal protein aggregation and cell death. The intricate relationship among protein lipoylation, cellular energy metabolism, and cuproptosis offers a promising avenue for regulating essential cellular functions. This review focuses on the mechanisms of lipoylation and its significant impact on cell metabolism and cuproptosis, emphasizing the key genes involved and their implications for human diseases. It offers valuable insights into targeting dysregulated cellular metabolism for therapeutic purposes.
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Cobre , Lipoilación , Mitocondrias , Humanos , Mitocondrias/metabolismo , Cobre/metabolismo , Animales , Proteínas Mitocondriales/metabolismo , Procesamiento Proteico-Postraduccional , Metabolismo EnergéticoRESUMEN
Chlamydia trachomatis is a clinically important bacterium that infects epithelial cells of the genitourinary and respiratory tracts and the eye. These differentiated cells are in a quiescent growth state and have a surface organelle called a primary cilium, but the standard Chlamydia cell culture infection model uses cycling cells that lack primary cilia. To investigate if these differences are relevant, we performed infections with host cells that have a primary cilium. We found that C. trachomatis caused progressive loss of the primary cilium that was prevented by disrupting Aurora A (AurA), HDAC6 or calmodulin, which are components of the cellular cilia disassembly pathway. Stabilization of the primary cilium by targeting this pathway caused a large reduction in infectious progeny although there were no changes in chlamydial inclusion growth, chlamydial replication or the ultrastructural appearance of dividing and infectious forms (RBs and EBs, respectively). Thus, the presence of a primary cilium interfered with the production of infectious EBs at a late step in the developmental cycle. C. trachomatis infection also induced quiescent cells to re-enter the cell cycle, as detected by EdU incorporation in S-phase, and Chlamydia-induced cilia disassembly was necessary for cell cycle re-entry. This study therefore describes a novel host-pathogen interaction in which the primary cilium limits a productive Chlamydia infection, and the bacterium counteracts this host cell defense by activating the cellular cilia disassembly pathway.
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Infecciones por Chlamydia , Chlamydia trachomatis , Cilios , Chlamydia trachomatis/fisiología , Cilios/microbiología , Cilios/metabolismo , Infecciones por Chlamydia/microbiología , Infecciones por Chlamydia/metabolismo , Infecciones por Chlamydia/patología , Humanos , Células Epiteliales/microbiología , Células Epiteliales/metabolismoRESUMEN
Rotaviruses (RVs) preferentially replicate in the small intestine and frequently cause severe diarrheal disease, and the following enteric infection generally induces variable levels of protective systemic and mucosal immune responses in humans and other animals. Rhesus rotavirus (RRV) is a simian RV that was previously used as a human RV vaccine and has been extensively studied in mice. Although RRV replicates poorly in the suckling mouse intestine, infection induces a robust and protective antibody response. The recent availability of plasmid only-based RV reverse genetics systems has enabled the generation of recombinant RVs expressing foreign proteins. However, recombinant RVs have not yet been experimentally tested as potential vaccine vectors to immunize against other gastrointestinal pathogens in vivo. This is a newly available opportunity because several live-attenuated RV vaccines are already widely administered to infants and young children worldwide. To explore the feasibility of using RV as a dual vaccine vector, we rescued replication-competent recombinant RRVs harboring bicistronic gene segment 7 that encodes the native RV nonstructural protein 3 (NSP3) protein and a human norovirus (HuNoV) VP1 protein or P domain from the predominant genotype GII.4. The rescued viruses expressed HuNoV VP1 or P protein in infected cells in vitro and elicited systemic and local antibody responses to HuNoV and RRV following oral infection of suckling mice. Serum IgG and fecal IgA from infected suckling mice bound to and neutralized both RRV and HuNoV. These findings have encouraging practical implications for the design of RV-based next-generation multivalent enteric vaccines to target HuNoV and other human enteric pathogens.
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Norovirus , Infecciones por Rotavirus , Rotavirus , Niño , Lactante , Humanos , Animales , Ratones , Preescolar , Rotavirus/genética , Anticuerpos Neutralizantes , Membrana Mucosa , Anticuerpos AntiviralesRESUMEN
BACKGROUND: Progressive hepatitis B virus (HBV) infection can result in cirrhosis, hepatocellular cancer, and chronic hepatitis. While antiviral drugs that are now on the market are efficient in controlling HBV infection, finding a functional cure is still quite difficult. Identifying host factors involved in regulating the HBV life cycle will contribute to the development of new antiviral strategies. Zinc finger proteins have a significant function in HBV replication, according to earlier studies. Zinc finger protein 148 (ZNF148), a zinc finger transcription factor, regulates the expression of various genes by specifically binding to GC-rich sequences within promoter regions. The function of ZNF148 in HBV replication was investigated in this study. METHODS: HepG2-Na+/taurocholate cotransporting polypeptide (HepG2-NTCP) cells and Huh7 cells were used to evaluate the function of ZNF148 in vitro. Northern blotting and real-time PCR were used to quantify the amount of viral RNA. Southern blotting and real-time PCR were used to quantify the amount of viral DNA. Viral protein levels were elevated, according to the Western blot results. Dual-luciferase reporter assays were used to examine the transcriptional activity of viral promoters. ZNF148's impact on HBV in vivo was investigated using an established rcccDNA mouse model. RESULTS: ZNF148 overexpression significantly decreased the levels of HBV RNAs and HBV core DNA in HBV-infected HepG2-NTCP cells and Huh7 cells expressing prcccDNA. Silencing ZNF148 exhibited the opposite effects in both cell lines. Furthermore, ZNF148 inhibited the activity of HBV ENII/Cp and the transcriptional activity of cccDNA. Mechanistic studies revealed that ZNF148 attenuated retinoid X receptor alpha (RXRα) expression by binding to the RXRα promoter sequence. RXRα binding site mutation or RXRα overexpression abolished the suppressive effect of ZNF148 on HBV replication. The inhibitory effect of ZNF148 was also observed in the rcccDNA mouse model. CONCLUSIONS: ZNF148 inhibited HBV replication by downregulating RXRα transcription. Our findings reveal that ZNF148 may be a new target for anti-HBV strategies.
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Virus de la Hepatitis B , Hepatitis B , Animales , Humanos , Ratones , ADN Viral/genética , Células Hep G2 , Virus de la Hepatitis B/fisiología , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Replicación ViralRESUMEN
BACKGROUND: Bacterial vaginosis (BV) is a widely occurring vaginal inflammation in women of childbearing age caused by dysbiosis of the vaginal flora. Few studies have investigated the effect of serum carotenoids on the development and pathogenesis of BV. This study thus aimed to explore the correlation between serum carotenoids and BV in American women. METHOD: The analysis included 1252 participants with BV from the National Health and Nutrition Examination Survey (NHANES) between 2001 and 2004. Multiple logistic regression was conducted to explore the correlation between BV and serum carotenoids, while smooth curve fitting was utilized to examine potential nonlinear correlations. Furthermore, stratified subgroup analyses and sensitivity analyses were conducted. ORs reflected the correlation between BV and serum carotenoids. RESULT: Results of multiple logistic regression indicated that total serum carotenoids and BV had an inverse correlation. In the fully adjusted model II, the quartile with the highest levels of α-carotene and ß-cryptoxanthin had a substantially lower incidence of BV. Smooth curve fitting revealed a significant negative linear correlation between serum carotenoids and the incidence of BV. The negative correlation between serum carotenoids and BV was relatively stable in stratified analyses. Moreover, in sensitivity analyses, the association between serum carotenoids and BV persisted, and ß-carotene became significantly negatively correlated with BV. CONCLUSION: This study found an inverse correlation between serum carotenoids and the prevalence of BV.
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Vaginosis Bacteriana , Humanos , Femenino , Estados Unidos/epidemiología , Encuestas Nutricionales , Vaginosis Bacteriana/epidemiología , Carotenoides , beta Caroteno , AntioxidantesRESUMEN
Dysregulation of MLL complex-mediated histone methylation plays a pivotal role in gene expression associated with diseases, but little is known about cellular factors modulating MLL complex activity. Here, we report that SON, previously known as an RNA splicing factor, controls MLL complex-mediated transcriptional initiation. SON binds to DNA near transcription start sites, interacts with menin, and inhibits MLL complex assembly, resulting in decreased H3K4me3 and transcriptional repression. Importantly, alternatively spliced short isoforms of SON are markedly upregulated in acute myeloid leukemia. The short isoforms compete with full-length SON for chromatin occupancy but lack the menin-binding ability, thereby antagonizing full-length SON function in transcriptional repression while not impairing full-length SON-mediated RNA splicing. Furthermore, overexpression of a short isoform of SON enhances replating potential of hematopoietic progenitors. Our findings define SON as a fine-tuner of the MLL-menin interaction and reveal short SON overexpression as a marker indicating aberrant transcriptional initiation in leukemia.
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Proteínas de Unión al ADN/genética , N-Metiltransferasa de Histona-Lisina/biosíntesis , Leucemia Mieloide Aguda/genética , Proteína de la Leucemia Mieloide-Linfoide/biosíntesis , Proteínas Proto-Oncogénicas/genética , Transcripción Genética , Empalme Alternativo/genética , Línea Celular Tumoral , Cromatina/genética , Proteínas de Unión al ADN/biosíntesis , Regulación Leucémica de la Expresión Génica , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Leucemia Mieloide Aguda/patología , Metilación , Antígenos de Histocompatibilidad Menor , Proteína de la Leucemia Mieloide-Linfoide/genética , Unión Proteica , Isoformas de Proteínas/genética , Proteínas Proto-Oncogénicas/metabolismoRESUMEN
As the landscape becomes more urbanized, snakebites have increasingly become uncommon presentations to the emergency departments in Singapore, while snakebites causing significant envenomation are even rarer. In this case report, we discuss a 55-year-old man who had significant envenomation from a Shore Pit Viper (Trimeresurus Purpureomaculatus) and who was successfully treated with haemato-toxic polyvalent antivenom (HPAV). He initially presented with pain, swelling and bleeding over his wound. Due to a deterioration in his coagulation profile, he was given two doses of HPAV which is typically reserved for viperid snakes instead. Following administration of the anti-venom, the patient's coagulation profile improved, and the local soft tissue effects of the venom resolved. He did not manifest any adverse effects and was discharged uneventfully about 72 h after the snakebite. The cross-neutralization potential of HPAV for Shore Pit Viper (Trimeresurus Purpureomaculatus) venom in this case study suggests that there may be a possible common underlying chemical structure and pathophysiology among the venom proteins of various snake species. Given that Trimeresurus-specific antivenom is unavailable in most countries, this cross-neutralization strategy deserves further consideration and evaluation in similar circumstances.
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Group A rotaviruses cause severe gastroenteritis in infants and young children worldwide, with P[II] genogroup rotaviruses (RVs) responsible for >90% of global cases. RVs have diverse host ranges in different human and animal populations determined by host histo-blood group antigen (HBGA) receptor polymorphism, but details governing diversity, host ranges, and species barriers remain elusive. In this study, crystal structures of complexes of the major P[II] genogroup P[4] and P[8] genotype RV VP8* receptor-binding domains together with Lewis epitope-containing LNDFH I glycans in combination with VP8* receptor-glycan ligand affinity measurements based on NMR titration experiments revealed the structural basis for RV genotype-specific switching between ßß and ßα HBGA receptor-binding sites that determine RV host ranges. The data support the hypothesis that P[II] RV evolution progressed from animals to humans under the selection of type 1 HBGAs guided by stepwise host synthesis of type 1 ABH and Lewis HBGAs. The results help explain disease burden, species barriers, epidemiology, and limited efficacy of current RV vaccines in developing countries. The structural data has the potential to impact the design of future vaccine strategies against RV gastroenteritis.
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Antígenos de Grupos Sanguíneos/inmunología , Evolución Molecular , Rotavirus/genética , Cristalografía por Rayos X , Especificidad del Huésped/genética , Humanos , Resonancia Magnética Nuclear Biomolecular/métodos , Conformación Proteica , Rotavirus/química , Rotavirus/inmunología , Proteínas no Estructurales Virales/química , Vacunas Virales/inmunologíaRESUMEN
Restoration of human brain function after injury is a signal challenge for translational neuroscience. Rodent stroke recovery studies identify an optimal or sensitive period for intensive motor training after stroke: near-full recovery is attained if task-specific motor training occurs during this sensitive window. We extended these findings to adult humans with stroke in a randomized controlled trial applying the essential elements of rodent motor training paradigms to humans. Stroke patients were adaptively randomized to begin 20 extra hours of self-selected, task-specific motor therapy at ≤30 d (acute), 2 to 3 mo (subacute), or ≥6 mo (chronic) after stroke, compared with controls receiving standard motor rehabilitation. Upper extremity (UE) impairment assessed by the Action Research Arm Test (ARAT) was measured at up to five time points. The primary outcome measure was ARAT recovery over 1 y after stroke. By 1 y we found significantly increased UE motor function in the subacute group compared with controls (ARAT difference = +6.87 ± 2.63, P = 0.009). The acute group compared with controls showed smaller but significant improvement (ARAT difference = +5.25 ± 2.59 points, P = 0.043). The chronic group showed no significant improvement compared with controls (ARAT = +2.41 ± 2.25, P = 0.29). Thus task-specific motor intervention was most effective within the first 2 to 3 mo after stroke. The similarity to rodent model treatment outcomes suggests that other rodent findings may be translatable to human brain recovery. These results provide empirical evidence of a sensitive period for motor recovery in humans.
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Actividad Motora/fisiología , Recuperación de la Función , Rehabilitación de Accidente Cerebrovascular/métodos , Accidente Cerebrovascular/terapia , Anciano , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios ProspectivosRESUMEN
Cotton is essential for the textile industry as a primary source of natural fibers. However, environmental factors like drought present significant challenges to its cultivation, adversely affecting both production levels and fiber quality. Enhancing cotton's drought resilience has the potential to reduce yield losses and support the growth of cotton farming. In this study, the cotton calcium-dependent protein kinase GhCDPK16 was characterized, and the transcription level of GhCDPK16 was significantly upregulated under drought and various stress-related hormone treatments. Physiological analyses revealed that the overexpression of GhCDPK16 improved drought stress resistance in Arabidopsis by enhancing osmotic adjustment capacity and boosting antioxidant enzyme activities. In contrast, silencing GhCDPK16 in cotton resulted in increased dehydration compared with the control. Furthermore, reduced antioxidant enzyme activities and downregulation of ABA-related genes were observed in GhCDPK16-silenced plants. These findings not only enhanced our understanding of the biological functions of GhCDPK16 and the mechanisms underlying drought stress resistance but also underscored the considerable potential of GhCDPK16 in improving drought resilience in cotton.
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Resistencia a la Sequía , Regulación de la Expresión Génica de las Plantas , Gossypium , Proteínas de Plantas , Proteínas Quinasas , Estrés Fisiológico , Arabidopsis/genética , Arabidopsis/fisiología , Resistencia a la Sequía/genética , Gossypium/genética , Gossypium/metabolismo , Gossypium/fisiología , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Plantas Modificadas Genéticamente , Proteínas Quinasas/metabolismo , Proteínas Quinasas/genéticaRESUMEN
PURPOSE: To study the effect of implant angulation on 3D linear and absolute angular distortions of implant analogs in printed resin models and conventional stone casts. MATERIALS AND METHODS: Three sectional master models with two implants with total inter-implant angulations of 0°, 10°, and 20° were fabricated. For each master model, five conventional stone casts (CS) and printed resin models (PM) were fabricated (n = 5). Test models were made with nonsplinted impression copings and open tray polyether impressions for the CS groups and scan bodies scanned using an intraoral scanner for the PM groups. The physical positions of the implants and implant analogs were measured with a coordinate measuring machine. 3D linear distortion (ΔR) and absolute angular distortion (Absdθ) defined the 3D positional accuracy of the analogs in the test models. Univariate ANOVA was used to analyze data followed by post hoc tests (Tukey HSD, α = 0.05). RESULTS: Mean ΔR was significantly greater for PM10 (73.5 ± 8.9 µm) and PM20 (65.5 ± 33.3 µm) compared to CS0 (16.8 ± 14.1 µm), CS10 (22.2 ± 13.0 µm), CS20 (15.6 ± 19.9 µm), and PM0 (23.9 ± 16.1 µm). For Absdθ, there were no significant differences between test groups. CONCLUSIONS: With conventional stone casts, implant angulation had no significant effect on 3D linear and absolute angular distortions. Amongst printed resin models test groups, angulated implants had significantly greater ΔR. Amongst angulated implants test groups, printed resin models had significantly greater ΔR than conventional stone casts. Compared to the master model, all test groups, regardless of inter-implant angulation, produced greater inter-analog distances.
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Implantes Dentales , Materiales de Impresión Dental , Técnica de Impresión Dental , Modelos DentalesRESUMEN
BACKGROUND: Branching is a plastic character that affects plant architecture and spatial structure. The trait is controlled by a variety of plant hormones through coordination with environmental signals. Plant AT-rich sequence and zinc-binding protein (PLATZ) is a transcription factor that plays an important role in plant growth and development. However, systematic research on the role of the PLATZ family in apple branching has not been conducted previously. RESULTS: In this study, a total of 17 PLATZ genes were identified and characterized from the apple genome. The 83 PLATZ proteins from apple, tomato, Arabidopsis, rice, and maize were classified into three groups based on the topological structure of the phylogenetic tree. The phylogenetic relationships, conserved motifs, gene structure, regulatory cis-acting elements, and microRNAs of the MdPLATZ family members were predicted. Expression analysis revealed that MdPLATZ genes exhibited distinct expression patterns in different tissues. The expression patterns of the MdPLATZ genes were systematically investigated in response to treatments that impact apple branching [thidazuron (TDZ) and decapitation]. The expression of MdPLATZ1, 6, 7, 8, 9, 15, and 16 was regulated during axillary bud outgrowth based on RNA-sequencing data obtained from apple axillary buds treated by decapitation or exogenous TDZ application. Quantitative real-time PCR analysis showed that MdPLATZ6 was strongly downregulated in response to the TDZ and decapitation treatments, however, MdPLATZ15 was significantly upregulated in response to TDZ, but exhibited little response to decapitation. Furthermore, the co-expression network showed that PLATZ might be involved in shoot branching by regulating branching-related genes or mediating cytokinin or auxin pathway. CONCLUSION: The results provide valuable information for further functional investigation of MdPLATZ genes in the control of axillary bud outgrowth in apple.
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Decapitación , Malus , Malus/metabolismo , Filogenia , Decapitación/metabolismo , Genes de Plantas , Brotes de la Planta/genética , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
B7-H3 (CD276), a member of the B7 family of proteins, is a key player in cancer progression. This immune checkpoint molecule is selectively expressed in both tumor cells and immune cells within the tumor microenvironment. In addition to its immune checkpoint function, B7-H3 has been linked to tumor cell proliferation, metastasis, and therapeutic resistance. Furthermore, its drastic difference in protein expression levels between normal and tumor tissues suggests that targeting B7-H3 with drugs would lead to cancer-specific toxicity, minimizing harm to healthy cells. These properties make B7-H3 a promising target for cancer therapy.Recently, important advances in B7-H3 research and drug development have been reported, and these new findings, including its involvement in cellular metabolic reprograming, cancer stem cell enrichment, senescence and obesity, have expanded our knowledge and understanding of this molecule, which is important in guiding future strategies for targeting B7-H3. In this review, we briefly discuss the biology and function of B7-H3 in cancer development. We emphasize more on the latest findings and their underlying mechanisms to reflect the new advances in B7-H3 research. In addition, we discuss the new improvements of B-H3 inhibitors in cancer drug development.
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Desarrollo de Medicamentos , Factores de Transcripción , Humanos , Proliferación Celular , Proteínas de Punto de Control Inmunitario , Células Madre Neoplásicas , Antígenos B7RESUMEN
Human noroviruses (huNoVs) cause epidemic acute gastroenteritis using histo-blood group antigens (HBGAs) as host receptors or attachment factors to initiate an infection. While most huNoVs have been shown to bind HBGAs, some known clinical isolates, such as GI.3 DSV and VA115, do not recognize any HBGAs and thus the molecular mechanism behind their infections remains elusive. In this study, we provided both phenotypic and structural evidence to show that huNoV DSV and VA115 recognize a group of glycans with terminal galactoses as ligands. First, through glycan array we found that both DSV and VA115 protruding (P) domain proteins bound two oligosaccharides that share common terminal galactoses. Then, by determination of the crystal structures of DSV/VA115 P proteins in complex with Galα1-3Galß1-4Glc and/or NA2 N-Glycan, respectively, we showed that the terminal galactose is the main saccharide recognized by the two viral proteins. Our data demonstrated that GI huNoVs can interact with non-HBGA glycans through their conserved galactose binding site, shedding light on the mechanism of huNoV adaptation through recognizing new glycan receptors to facilitate their widespread nature in human population. These findings are also of significance in strategy development for huNoV control and prevention, as well as development of antiviral drugs. IMPORTANCE Human noroviruses (huNoVs) are the most important viral pathogens causing epidemic acute gastroenteritis worldwide. Previous studies indicated that histo-blood group antigens (HBGAs) are critical host-susceptibility factors affecting huNoV host susceptibility, host range, and probably prevalence. However, certain huNoVs, such as GI.3 DSV and VA115, do not recognize any HBGAs. This implies that other unknown host factors might exist and the molecular mechanism underlying their host receptor recognition or attachment remains elusive. In this study, we found that purified capsid protruding domain proteins from two GI.3 huNoVs specifically bind two glycans that contain a common terminal galactose. We solved the crystal structures of the complexes at atomic resolution and validated the vital amino acids involved in glycan recognition. Our findings elucidate the mechanism of GI.3 huNoV-non-HBGA glycan interaction, which explains why GI.3 virus strains could not bind human HBGAs, paving a way to the prevention and treatment of huNoV-associated diseases.
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Antígenos de Grupos Sanguíneos , Galactosa , Gastroenteritis , Norovirus , Sitios de Unión , Antígenos de Grupos Sanguíneos/metabolismo , Proteínas de la Cápside/metabolismo , Galactosa/metabolismo , Gastroenteritis/fisiopatología , Humanos , Norovirus/metabolismo , Unión ProteicaRESUMEN
The global SARS-CoV-2 coronavirus pandemic continues to be devastating in many areas. Treatment options have been limited and convalescent donor plasma has been used by many centers to transfer passive neutralizing antibodies to patients with respiratory involvement. The results often vary by institution and are complicated by the nature and quality of the donor plasma itself, the timing of administration and the clinical aspects of the recipients. SARS-CoV-2 infection is known to be associated with an increase in the blood concentrations of several inflammatory cytokines/chemokines, as part of the overall immune response to the virus and consequential to mediated lung pathology. Some of these correlates contribute to the cytokine storm syndrome and acute respiratory distress syndrome, often resulting in fatality. A Phase IIa clinical trial at our institution using high neutralizing titer convalescent plasma transfer gave us the unique opportunity to study the elevations of correlates in the first 10 days after infusion. Plasma recipients were divided into hospitalized COVID-19 pneumonia patients who did not (Track 2) or did (Track 3) require mechanical ventilation. Several cytokines were elevated in the patients of each Track and some continued to rise through Day 10, while others initially increased and then subsided. Furthermore, elevations in MIP-1α, MIP-1ß and CRP correlated with disease progression of Track 2 recipients. Overall, our observations serve as a foundation for further study of these correlates and the identification of potential biomarkers to improve upon convalescent plasma therapy and to drive more successful patient outcomes.
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COVID-19/terapia , Quimiocinas/sangre , Citocinas/sangre , SARS-CoV-2 , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , COVID-19/inmunología , Femenino , Humanos , Inmunización Pasiva , Isotipos de Inmunoglobulinas/sangre , Masculino , Persona de Mediana Edad , Sueroterapia para COVID-19RESUMEN
Hepatitis B surface antigen (HBsAg) loss and seroconversion, which is considered as functional cure of chronic Hepatitis B virus (HBV) infection, is rarely achieved even after long-term antiviral treatments. Therefore, new antiviral strategies interfering with other HBV replication steps are required, especially those that could efficiently inhibit HBsAg production. Here, we identified novel anti-HBV compounds that could potently block HBsAg expression from cccDNA by screening a natural compound library derived from Chinese traditional medical plants by a novel screening strategy. The combination of ELISA assay detecting the HBsAg and real-time PCR detecting HBV RNAs as indicator for cccDNA transcriptional activity were used. The antiviral activity of a candidate compound and underlying mechanism were evaluated in HBV-infected cells and a humanized liver mouse model. Herein, we selected a highly effective low-cytotoxic compound sphondin, which could effectively inhibit both intracellular HBsAg production and HBV RNAs levels. Moreover, we found that sphondin markedly inhibited cccDNA transcriptional activity without affecting cccDNA level. Mechanistic study found sphondin preferentially bound to HBx protein by residue Arg72, which led to increased 26S proteasome-mediated degradation of HBx. Sphondin treatment significantly reduced the recruitment of HBx to cccDNA, which subsequently led to inhibition of cccDNA transcription and HBsAg expression. The absence of HBx or R72A mutation potently abrogated the antiviral effect induced by sphondin in HBV-infected cells. Collectively, sphondin may be considered as a novel and natural antiviral agent directly targeting HBx protein, which effectively inhibited cccDNA transcription and HBsAg expression.
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Antígenos de Superficie de la Hepatitis B , Hepatitis B Crónica , Animales , Ratones , Antígenos de Superficie de la Hepatitis B/genética , Hepatitis B Crónica/tratamiento farmacológico , Virus de la Hepatitis B/fisiología , Antivirales/uso terapéutico , ADN Viral/genética , ADN Circular , Replicación ViralRESUMEN
Direct, amplification-free detection of RNA has the potential to transform molecular diagnostics by enabling simple on-site analysis of human or environmental samples. CRISPR-Cas nucleases offer programmable RNA-guided RNA recognition that triggers cleavage and release of a fluorescent reporter molecule, but long reaction times hamper their detection sensitivity and speed. Here, we show that unrelated CRISPR nucleases can be deployed in tandem to provide both direct RNA sensing and rapid signal generation, thus enabling robust detection of ~30 molecules per µl of RNA in 20 min. Combining RNA-guided Cas13 and Csm6 with a chemically stabilized activator creates a one-step assay that can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA extracted from respiratory swab samples with quantitative reverse transcriptase PCR (qRT-PCR)-derived cycle threshold (Ct) values up to 33, using a compact detector. This Fast Integrated Nuclease Detection In Tandem (FIND-IT) approach enables sensitive, direct RNA detection in a format that is amenable to point-of-care infection diagnosis as well as to a wide range of other diagnostic or research applications.