RESUMEN
Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic condition characterized by features of accelerated aging, and individuals with HGPS seldom live beyond their mid-teens. The syndrome is commonly caused by a point mutation in the LMNA gene which codes for lamin A and its splice variant lamin C, components of the nuclear lamina. The mutation causing HGPS leads to production of a truncated, farnesylated form of lamin A referred to as "progerin." Progerin is also expressed at low levels in healthy individuals and appears to play a role in normal aging. HGPS is associated with an accumulation of genomic DNA double-strand breaks (DSBs) and alterations in the nature of DSB repair. The source of DSBs in HGPS is often attributed to stalling and subsequent collapse of replication forks in conjunction with faulty recruitment of repair factors to damage sites. In this work, we used a model system involving immortalized human cell lines to investigate progerin-induced genomic damage. Using an immunofluorescence approach to visualize phosphorylated histone H2AX foci which mark sites of genomic damage, we report that cells engineered to express progerin displayed a significant elevation of endogenous damage in the absence of any change in the cell cycle profile or doubling time of cells. Genomic damage was enhanced and persistent in progerin-expressing cells treated with hydroxyurea. Overexpression of wild-type lamin A did not elicit the outcomes associated with progerin expression. Our results show that DNA damage caused by progerin can occur independently from global changes in replication or cell proliferation.
RESUMEN
CTC1-STN1-TEN1 (CST) is a single-stranded DNA binding protein vital for telomere length maintenance with additional genome-wide roles in DNA replication and repair. While CST was previously shown to function in double-strand break repair and promote replication restart, it is currently unclear whether it has specialized roles in other DNA repair pathways. Proper and efficient repair of DNA is critical to protecting genome integrity. Telomeres and other G-rich regions are strongly predisposed to oxidative DNA damage in the form of 8-oxoguanines, which are typically repaired by the base-excision repair (BER) pathway. Moreover, recent studies suggest that CST functions in the repair of oxidative DNA lesions. Therefore, we tested whether CST interacts with and regulates BER protein activity. Here, we show that CST robustly stimulates proteins involved in BER, including OGG1, Pol ß, APE1, and LIGI, on both telomeric and non-telomeric DNA substrates. Biochemical reconstitution of the pathway indicates that CST stimulates BER. Finally, knockout of STN1 or CTC1 leads to increased levels of 8-oxoguanine, suggesting defective BER in the absence of CST. Combined, our results define an undiscovered function of CST in BER, where it acts as a stimulatory factor to promote efficient genome-wide oxidative repair.
Asunto(s)
Daño del ADN , Reparación del ADN , Proteínas de Unión a Telómeros , Humanos , Proteínas de Unión a Telómeros/metabolismo , Proteínas de Unión a Telómeros/genética , Telómero/metabolismo , Telómero/genética , ADN Glicosilasas/metabolismo , ADN Glicosilasas/genética , Estrés Oxidativo , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , ADN-(Sitio Apurínico o Apirimidínico) Liasa/genética , Guanina/análogos & derivados , Guanina/metabolismo , ADN Polimerasa beta/metabolismo , ADN Polimerasa beta/genética , Reparación por EscisiónRESUMEN
BACKGROUND: The registry-based randomized VALIDATE-SWEDEHEART trial (NCT02311231) compared bivalirudin vs. heparin in patients undergoing percutaneous coronary intervention (PCI) for myocardial infarction (MI). It showed no difference in the composite primary endpoint of death, MI, or major bleeding at 180 days. Here, we report outcomes at two years. METHODS: Analysis of primary and secondary endpoints at two years of follow-up was prespecified in the study protocol. We report the study results for the extended follow-up time here. RESULTS: In total, 6006 patients were enrolled, 3005 with ST-segment elevation MI (STEMI) and 3001 with Non-STEMI (NSTEMI), representing 70 % of all eligible patients with these diagnoses during the study. The primary endpoint occurred in 14.0 % (421 of 3004) in the bivalirudin group compared with 14.3 % (429 of 3002) in the heparin group (hazard ratio [HR] 0.97; 95 % confidence interval [CI], 0.85-1.11; P = 0.70) at one year and in 16.7 % (503 of 3004) compared with 17.1 % (514 of 3002), (HR 0.97; 95 % CI, 0.96-1.10; P = 0.66) at two years. The results were consistent in patients with STEMI and NSTEMI and across major subgroups. CONCLUSIONS: Until the two-year follow-up, there were no differences in endpoints between patients with MI undergoing PCI and allocated to bivalirudin compared with those allocated to heparin. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02311231.
Asunto(s)
Anticoagulantes , Antitrombinas , Hemorragia , Heparina , Hirudinas , Infarto del Miocardio sin Elevación del ST , Fragmentos de Péptidos , Intervención Coronaria Percutánea , Proteínas Recombinantes , Sistema de Registros , Infarto del Miocardio con Elevación del ST , Humanos , Hirudinas/efectos adversos , Hirudinas/administración & dosificación , Heparina/efectos adversos , Heparina/uso terapéutico , Heparina/administración & dosificación , Fragmentos de Péptidos/uso terapéutico , Fragmentos de Péptidos/efectos adversos , Infarto del Miocardio con Elevación del ST/terapia , Infarto del Miocardio con Elevación del ST/mortalidad , Infarto del Miocardio con Elevación del ST/diagnóstico , Intervención Coronaria Percutánea/efectos adversos , Intervención Coronaria Percutánea/mortalidad , Proteínas Recombinantes/uso terapéutico , Proteínas Recombinantes/efectos adversos , Proteínas Recombinantes/administración & dosificación , Masculino , Resultado del Tratamiento , Femenino , Factores de Tiempo , Anciano , Persona de Mediana Edad , Antitrombinas/efectos adversos , Antitrombinas/uso terapéutico , Antitrombinas/administración & dosificación , Anticoagulantes/efectos adversos , Anticoagulantes/uso terapéutico , Hemorragia/inducido químicamente , Infarto del Miocardio sin Elevación del ST/terapia , Infarto del Miocardio sin Elevación del ST/mortalidad , Infarto del Miocardio sin Elevación del ST/diagnóstico , Infarto del Miocardio sin Elevación del ST/diagnóstico por imagen , Factores de Riesgo , SueciaRESUMEN
Human CST (CTC1-STN1-TEN1) is a ssDNA-binding complex that interacts with the replisome to aid in stalled fork rescue. We previously found that CST promotes telomere replication to maintain genomic integrity via G-quadruplex (G4) resolution. However, the detailed mechanism by which CST resolves G4s in vivo and whether additional factors are involved remains unclear. Here, we identify RECQ4 as a novel CST-interacting partner and show that RECQ4 can unwind G4 structures in vitro using a FRET assay. Moreover, G4s accumulate at the telomere after RECQ4 depletion, resulting in telomere dysfunction, including the formation of MTSs, SFEs, and TIFs, suggesting that RECQ4 is crucial for telomere integrity. Furthermore, CST is also required for RECQ4 telomere or chromatin localization in response to G4 stabilizers. RECQ4 is involved in preserving genomic stability by CST and RECQ4 disruption impairs restart of replication forks stalled by G4s. Overall, our findings highlight the essential roles of CST and RECQ4 in resolving G-rich regions, where they collaborate to resolve G4-induced replication deficiencies and maintain genomic homeostasis.
Asunto(s)
Replicación del ADN , G-Cuádruplex , Humanos , Proteínas de Unión a Telómeros/genética , Homeostasis del Telómero , Telómero/metabolismoRESUMEN
CST (CTC1-STN1-TEN1) is a telomere associated complex that binds ssDNA and is required for multiple steps in telomere replication, including termination of G-strand extension by telomerase and synthesis of the complementary C-strand. CST contains seven OB-folds which appear to mediate CST function by modulating CST binding to ssDNA and the ability of CST to recruit or engage partner proteins. However, the mechanism whereby CST achieves its various functions remains unclear. To address the mechanism, we generated a series of CTC1 mutants and studied their effect on CST binding to ssDNA and their ability to rescue CST function in CTC1-/- cells. We identified the OB-B domain as a key determinant of telomerase termination but not C-strand synthesis. CTC1-ΔB expression rescued C-strand fill-in, prevented telomeric DNA damage signaling and growth arrest. However, it caused progressive telomere elongation and the accumulation of telomerase at telomeres, indicating an inability to limit telomerase action. The CTC1-ΔB mutation greatly reduced CST-TPP1 interaction but only modestly affected ssDNA binding. OB-B point mutations also weakened TPP1 association, with the deficiency in TPP1 interaction tracking with an inability to limit telomerase action. Overall, our results indicate that CTC1-TPP1 interaction plays a key role in telomerase termination.
Asunto(s)
Telomerasa , Humanos , Línea Celular , ADN de Cadena Simple/genética , Mutación , Telomerasa/genética , Telomerasa/metabolismo , Telómero/genética , Telómero/metabolismo , Homeostasis del Telómero , Proteínas de Unión a Telómeros/genética , Proteínas de Unión a Telómeros/metabolismoRESUMEN
Background: Prognostic assessment of ventricular tachycardia (VT) or ventricular fibrillation (VF) in ST-segment elevation myocardial infarction (STEMI) is based mainly on distinguishing between early (<48 hours) and late arrhythmias, and does not take into account its time distribution with regard to reperfusion, or type of arrhythmia. Objective: We analyzed the prognostic value of early ventricular arrhythmias (VAs) in STEMI with regard to their type and timing. Methods: The prespecified analysis of the multicenter prospective Bivalirudin versus Heparin in ST-Segment and Non-ST-Segment Elevation Myocardial Infarctionin Patients on Modern Antiplatelet Therapy in the Swedish Web System for Enhancement and Development of Evidence-based Care in Heart Disease evaluated according to Recommended Therapies Registry Trial included 2886 STEMI patients undergoing primary percutaneous coronary intervention (PCI). VA episodes were characterized regarding their type and timing. Survival status at 180 days was assessed through the population registry. Results: Nonmonomorphic VT or VF was observed in 97 (3.4%) and monomorphic VT in 16 (0.5%) patients. Only 3 (2.7%) early VA episodes occurred after 24 hours from symptom onset. VA was associated with higher risk of death (hazard ratio 3.59; 95% confidence interval [CI] 2.01-6.42) after adjustment for age, sex, and STEMI localization. VA after PCI was associated with an increased mortality compared with VA before PCI (hazard ratio 6.68; 95% CI 2.90-15.41). Early VA was associated with in-hospital mortality (odds ratio 7.39; 95% CI 3.68-14.83) but not with long-term prognosis in patients discharged alive. The type of VA was not associated with mortality. Conclusion: VA after PCI was associated with an increased mortality compared with VA before PCI. Long-term prognosis did not differ between patients with monomorphic VT and nonmonomorphic VT or VF, but events were few. VA incidence during 24 to 48 hours of STEMI is negligibly low, thus precluding assessment of its prognostic importance.
RESUMEN
Generating long-lived mucosal and systemic antibodies through respiratory immunization with protective antigens encapsulated in nanoscale biodegradable particles could potentially decrease or eliminate the incidence of many infectious diseases, but requires the incorporation of a suitable mucosal immunostimulant. We previously found that respiratory immunization with a model protein antigen (LPS-free OVA) encapsulated in PLGA 50:50 nanoparticles (~380 nm diameter) surface-modified with complement peptide-derived immunostimulant 02 (CPDI-02; formerly EP67) through 2 kDa PEG linkers increases mucosal and systemic OVA-specific memory T-cells with long-lived surface phenotypes in young, naïve female C57BL/6 mice. Here, we determined if respiratory immunization with LPS-free OVA encapsulated in similar PLGA 50:50 microparticles (~1 µm diameter) surface-modified with CPDI-02 (CPDI-02-MP) increases long-term OVA-specific mucosal and systemic antibodies. We found that, compared to MP surface-modified with inactive, scrambled scCPDI-02 (scCPDI-02-MP), intranasal administration of CPDI-02-MP in 50 µL sterile PBS greatly increased titers of short-term (14 days post-immunization) and long-term (90 days post-immunization) antibodies against encapsulated LPS-free OVA in nasal lavage fluids, bronchoalveolar lavage fluids, and sera of young, naïve female C57BL/6 mice with minimal lung inflammation. Thus, surface modification of ~1 µm biodegradable microparticles with CPDI-02 is likely to increase long-term mucosal and systemic antibodies against encapsulated protein antigen after respiratory and possibly other routes of mucosal immunization.
RESUMEN
Serum tyrosine levels increase during aging, neurocognitive, metabolic, and cardiovascular disorders. However, calorie restriction (CR) and sleep lower serum tyrosine levels. We previously showed that tyrosine inhibits tyrosyl-tRNA synthetase (TyrRS)-mediated activation of poly-ADP-ribose polymerase 1 (PARP1). Here, we show that histone serine-ADP-ribosylation is decreased in Alzheimer's Disease (AD) brains, and increased tyrosine levels deplete TyrRS and cause neuronal DNA damage. However, dopamine and brain-derived neurotrophic factor (BDNF) increase TyrRS and histone serine-ADP-ribosylation. Furthermore, cis-resveratrol (cis-RSV) that binds to TyrRS mimicking a 'tyrosine-free' conformation increases TyrRS, facilitates histone serine-ADP-ribosylation-dependent DNA repair, and provides neuroprotection in a TyrRS-dependent manner. Conversely, trans-RSV that binds to TyrRS mimicking a 'tyrosine-like' conformation decreases TyrRS, inhibits serine-ADP-ribosylation-dependent DNA repair, and induces neurodegeneration in rat cortical neurons. Our findings suggest that age-associated increase in serum tyrosine levels may effect neurocognitive and metabolic disorders and offer a plausible explanation for divergent results obtained in clinical trials using resveratrol.
Asunto(s)
Histonas , Tirosina-ARNt Ligasa , ADP-Ribosilación , Animales , Histonas/metabolismo , Ratas , Resveratrol/farmacología , Serina/metabolismo , Tirosina/metabolismo , Tirosina-ARNt Ligasa/metabolismoRESUMEN
Sister chromatid cohesion (SCC), the pairing of sister chromatids after DNA replication until mitosis, is established by loading of the cohesin complex on newly replicated chromatids. Cohesin must then be maintained until mitosis to prevent segregation defects and aneuploidy. However, how SCC is established and maintained until mitosis remains incompletely understood, and emerging evidence suggests that replication stress may lead to premature SCC loss. Here, we report that the ssDNA-binding protein CTC1-STN1-TEN1 (CST) aids in SCC. CST primarily functions in telomere length regulation but also has known roles in replication restart and DNA repair. After depletion of CST subunits, we observed an increase in the complete loss of SCC. In addition, we determined that CST associates with the cohesin complex. Unexpectedly, we did not find evidence of altered cohesin loading or mitotic progression in the absence of CST; however, we did find that treatment with various replication inhibitors increased the association between CST and cohesin. Because replication stress was recently shown to induce SCC loss, we hypothesized that CST may be required to maintain or remodel SCC after DNA replication fork stalling. In agreement with this idea, SCC loss was greatly increased in CST-depleted cells after exogenous replication stress. Based on our findings, we propose that CST aids in the maintenance of SCC at stalled replication forks to prevent premature cohesion loss.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromosómicas no Histona/metabolismo , Cromosomas Humanos , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión a Telómeros/metabolismo , Acetilación , Proteoglicanos Tipo Condroitín Sulfato/metabolismo , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Mitosis , Unión Proteica , Intercambio de Cromátides Hermanas , CohesinasRESUMEN
The regulation of DNA double-strand breaks (DSBs) and telomeres are diametrically opposed in the cell. DSBs are considered one of the most deleterious forms of DNA damage and must be quickly recognized and repaired. Telomeres, on the other hand, are specialized, stable DNA ends that must be protected from recognition as DSBs to inhibit unwanted chromosome fusions. Decisions to join DNA ends, or not, are therefore critical to genome stability. Yet, the processing of telomeres and DSBs share many commonalities. Accordingly, key decision points are used to shift DNA ends toward DSB repair vs. end protection. Additionally, DSBs can be repaired by two major pathways, namely homologous recombination (HR) and non-homologous end joining (NHEJ). The choice of which repair pathway is employed is also dictated by a series of decision points that shift the break toward HR or NHEJ. In this review, we will focus on these decision points and the mechanisms that dictate end protection vs. DSB repair and DSB repair choice.
RESUMEN
Genome stability and maintenance pathways along with their requisite proteins are critical for the accurate duplication of genetic material, mutation avoidance, and suppression of human diseases including cancer. Many of these proteins participate in these pathways by binding directly to DNA, and a subset employ oligonucleotide/oligosaccharide binding folds (OB-fold) to facilitate the protein-DNA interactions. OB-fold motifs allow for sequence independent binding to single-stranded DNA (ssDNA) and can serve to position specific proteins at specific DNA structures and then, via protein-protein interaction motifs, assemble the machinery to catalyze the replication, repair, or recombination of DNA. This review provides an overview of the OB-fold structural organization of some of the most relevant OB-fold containing proteins for oncology and drug discovery. We discuss their individual roles in DNA metabolism, progress toward drugging these motifs and their utility as potential cancer therapeutics. While protein-DNA interactions were initially thought to be undruggable, recent reports of success with molecules targeting OB-fold containing proteins suggest otherwise. The potential for the development of agents targeting OB-folds is in its infancy, but if successful, would expand the opportunities to impinge on genome stability and maintenance pathways for more effective cancer treatment.
RESUMEN
Few studies have examined the biosocial pathways linking socioeconomic status (SES) to accelerated aging in a population-based sample of southern US women. Even fewer have examined the importance of chronic compared to perceived stress in linking SES to women's salivary telomere length (STL). Using data from a probability-based sample of 156 US women and structural equation modeling, we examined three pathways - chronic stress exposure, stress appraisal, and coping behavior - linking SES to STL. SES was positively associated with STL (ßTE = 0.16, p < .05). Everyday discrimination was negatively associated with STL (ßDE = -0.21, p < .05), but perceived stress was positively associated with STL (ßDE = 0.20, p < .05). Current smoking decreased STL (ßDE = -0.19, p < .01). Perceived stress acted to suppress the negative relationship of chronic stress exposure on STL. Given the dearth of STL studies that include measures of both perceived and chronic stress, our study supports the importance of disentangling stress measures and a biosocial approach to the study of accelerated aging.
Asunto(s)
Determinantes Sociales de la Salud , Telómero , Envejecimiento/genética , Femenino , Humanos , Clase Social , Factores Socioeconómicos , Telómero/genéticaRESUMEN
CST (CTC1-STN1-TEN1) is a heterotrimeric, RPA-like complex that binds to single-stranded DNA (ssDNA) and functions in the replication of telomeric and non-telomeric DNA. Previous studies demonstrated that deletion of CTC1 results in decreased cell proliferation and telomere DNA damage signaling. However, a detailed analysis of the consequences of conditional CTC1 knockout (KO) has not been fully elucidated. Here, we investigated the effects of CTC1 KO on cell cycle progression, genome-wide replication and activation of the DNA damage response. Consistent with previous findings, we demonstrate that CTC1 KO results in decreased cell proliferation, G2 arrest and RPA-bound telomeric ssDNA. However, despite the increased levels of telomeric RPA-ssDNA, global ATR-dependent CHK1 and p53 phosphorylation was not detected in CTC1 KO cells. Nevertheless, we show that RPA-ssDNA does activate ATR, leading to the phosphorylation of RPA and autophosphorylation of ATR. Further analysis determined that inactivation of ATR, but not CHK1 or ATM, suppressed the accumulation of G2 arrested cells and phosphorylated RPA following CTC1 removal. These results suggest that ATR is localized and active at telomeres but is unable to elicit a global checkpoint response through CHK1. Furthermore, CTC1 KO inhibited CHK1 phosphorylation following hydroxyurea-induced replication stress. Additional studies revealed that this suppression of CHK1 phosphorylation, following replication stress, is caused by decreased levels of the ATR activator TopBP1. Overall, our results identify CST as a novel regulator of the ATR-CHK1 pathway.
Asunto(s)
Proteínas Portadoras/química , Proteínas Portadoras/metabolismo , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Replicación del ADN/genética , ADN de Cadena Simple/metabolismo , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Transducción de Señal/genética , Proteínas de Unión a Telómeros/metabolismo , Telómero/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas Portadoras/genética , Proliferación Celular/genética , Daño del ADN/genética , Proteínas de Unión al ADN/genética , Puntos de Control de la Fase G2 del Ciclo Celular/genética , Técnicas de Inactivación de Genes , Células HCT116 , Humanos , Proteínas Nucleares/genética , Fosforilación , Estabilidad Proteica , Proteína de Replicación A/metabolismo , Proteínas de Unión a Telómeros/genética , TransfecciónRESUMEN
EP67 is a second-generation, human C5a-derived decapeptide agonist of C5a receptor 1 (C5aR1/CD88) that selectively activates mononuclear phagocytes over neutrophils to potentiate protective innate and adaptive immune responses while potentially minimizing neutrophil-mediated toxicity. Pro7 and N-methyl-Leu8 (Me-Leu8) amino acid residues within EP67 likely induce backbone structural changes that increase potency and selective activation of mononuclear phagocytes over neutrophils versus first-generation EP54. The low coupling efficiency between Pro7 and Me-Leu8 and challenging purification by HPLC, however, greatly increase scale-up costs of EP67 for clinical use. Thus, the goal of this study was to determine whether replacing Pro7 and/or Me-Leu8 with large-scale amenable amino acid residues predicted to induce similar structural changes (cyclohexylalanine7 and/or leucine8) sufficiently preserves EP67 activity in primary human mononuclear phagocytes and neutrophils. We found that EP67 analogues had similar potency, efficacy, and selective activation of mononuclear phagocytes over neutrophils. Thus, replacing Pro7 and/or Me-Leu8 with large-scale amenable amino acid residues predicted to induce similar structural changes is a suitable strategy to overcome scale-up challenges with EP67.
Asunto(s)
Adyuvantes Inmunológicos/química , Complemento C5a , Oligopéptidos/química , Sustitución de Aminoácidos , HumanosRESUMEN
Fluorescence in situ hybridization (FISH) is used to examine chromosomal abnormalities and DNA damage. Developed in the early 1980s, this technique remains an important tool for understanding chromosome biology and diagnosing genetic disease and cancer. Use of FISH on metaphase chromosomes allows the visualization of chromosomal abnormalities at specific loci. Here, we describe methods for creating metaphase chromosome spreads and the use of telomere FISH probes to detect chromosome ends.
Asunto(s)
Cromosomas Humanos/genética , Hibridación Fluorescente in Situ/métodos , Metafase , Imagen Molecular/métodos , Telómero/genética , Línea Celular , Cromosomas Humanos/química , ADN/genética , Humanos , Microscopía Fluorescente/métodos , Sondas Moleculares/química , Telómero/químicaRESUMEN
Human CTC1-STN1-TEN1 (CST) is an RPA-like single-stranded DNA-binding protein that interacts with DNA polymerase α-primase (pol α) and functions in telomere replication. Previous studies suggest that CST also promotes replication restart after fork stalling. However, the precise role of CST in genome-wide replication remains unclear. In this study, we sought to understand whether CST alters origin licensing and activation. Replication origins are licensed by loading of the minichromosome maintenance 2-7 (MCM) complex in G1 followed by replisome assembly and origin firing in S-phase. We find that CST directly interacts with the MCM complex and disrupts binding of CDT1 to MCM, leading to decreased origin licensing. We also show that CST enhances replisome assembly by promoting AND-1/pol α chromatin association. Moreover, these interactions are not dependent on exogenous replication stress, suggesting that CST acts as a specialized replication factor during normal replication. Overall, our findings implicate CST as a novel regulator of origin licensing and replisome assembly/fork progression through interactions with MCM, AND-1, and pol α.
Asunto(s)
Cromatina/metabolismo , Replicación del ADN/fisiología , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión a Telómeros/metabolismo , Proteínas de Ciclo Celular/metabolismo , ADN Polimerasa I/metabolismo , Puntos de Control de la Fase G1 del Ciclo Celular/fisiología , Técnicas de Silenciamiento del Gen , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Proteínas de Mantenimiento de Minicromosoma/metabolismo , ARN Interferente Pequeño/genética , Puntos de Control de la Fase S del Ciclo Celular/fisiología , Telómero/metabolismo , Proteínas de Unión a Telómeros/genéticaRESUMEN
Diarrheal diseases are a major cause of morbidity and mortality worldwide. They are most prevalent in settings with inadequate sanitation, poor hygiene and contaminated water. An important diarrheal pathogen in such settings is Shigella. No commercially available vaccine exists against shigellosis and immunity to the pathogen is serotype-restricted. We have previously shown that a polypeptide fusion of the Type Three Secretion Apparatus (T3SA) proteins IpaB and IpaD (named DBF) was efficacious as a vaccine against Shigella. Vaccination using different administration routes indicated that protection conferred by DBF did not fully correlate with antibodies. To define the immune responses involved in protection, we studied cellular responses to intranasal immunization with the DBF and the adjuvant dmLT. We found dendritic cell (DC) activation at the nasal associated lymphoid tissue (NALT). Activation markers CD86 and MHCII significantly increase in cells from immunized mice. Antigen exposure in vitro further confirmed the upregulation of CD80 and CD40 in primary dendritic cells. Animals immunized with antigen-primed dendritic cells were protected against Shigella infection, at levels comparable to the efficacy of immunization with the protein vaccine formulation. Therefore, we show that antigen-primed DCs are enough to provide immunity, and propose a mechanism of protection against Shigella spp. based on DC-mediated antigen presentation to T cells.
Asunto(s)
Traslado Adoptivo/métodos , Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Células Dendríticas/inmunología , Disentería Bacilar/prevención & control , Vacunas contra la Shigella/inmunología , Shigella flexneri/inmunología , Vacunación/métodos , Administración Intranasal , Animales , Antígeno B7-2/metabolismo , Polaridad Celular/inmunología , Citocinas/metabolismo , Disentería Bacilar/inmunología , Disentería Bacilar/mortalidad , Femenino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Vacunas contra la Shigella/administración & dosificación , Tasa de Supervivencia , Linfocitos T Colaboradores-Inductores/inmunologíaRESUMEN
Mass Spectrometry has commonly been used in the semi-conductor industry where maintaining a clean environment with minimum contaminants under high vacuum is crucial for successful manufacturing. Since the technology's early usage for pharmaceutical manufacturing in the 1980â¯s, particularly in the freeze-drying environment, much has changed. The focus of the current work is aimed at asking some key questions regarding the maturity of the technology, its challenges and importance of having an application-specific instrument for quantitative process analyses applied to freeze-drying. Furthermore, we compare the use of mass spectrometers in early installations from the '80s with recent experiences of the technology in the production and laboratory environments comparing data from different MS technologies. In addition, the manuscript covers broad application of the technology towards detection of and sensitivity for analytes including silicone oil and Helium. It also explores the option of using MS in detecting water vapor and nitrogen concentration not just in primary drying, but also in secondary drying. The technology, when purpose built, has the potential for use as a robust, multi-purpose PAT tool in the freeze-drying laboratory and production environments.
Asunto(s)
Liofilización/instrumentación , Tecnología Farmacéutica/instrumentación , Helio/química , Espectrometría de Masas/métodos , Nitrógeno/química , Aceites de Silicona/química , Vacio , Agua/químicaRESUMEN
The human CTC1-STN1-TEN1 (CST) complex is a single-stranded DNA binding protein that shares homology with RPA and interacts with DNA polymerase alpha/primase. CST complexes are conserved from yeasts to humans and function in telomere maintenance. A common role of CST across species is in the regulation of telomere extension by telomerase and C-strand fill-in synthesis. However, recent studies also indicate that CST promotes telomere duplex replication as well the rescue of stalled DNA replication at non-telomeric sites. Furthermore, CST dysfunction and mutation is associated with several genetic diseases and cancers. In this review, we will summarize what is known about CST with a particular focus on the emerging roles of CST in DNA replication and human disease.
Asunto(s)
Enfermedad/genética , Inestabilidad Genómica , Proteínas de Unión a Telómeros/genética , Replicación del ADN/genética , Humanos , Mutación , Neoplasias/genética , Homeostasis del Telómero/genética , Proteínas de Unión a Telómeros/metabolismoRESUMEN
BACKGROUND: Timely percutaneous coronary intervention (PCI) improves prognosis in ST-elevation myocardial infarction (STEMI). However, recent reports indicate that patients with STEMI who present during non-regular working hours (off-hours) have a worse prognosis. The aim of this study was to compare outcome between patients with STEMI who underwent primary PCI during off-hours and regular hours. METHODS: We retrieved data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) for all patients who underwent primary PCI in Region Västra Götaland due to STEMI between January 2004 and May 2013. We modeled unadjusted and adjusted Cox proportional-hazards regression and logistic regression models for the outcomes death, cardiogenic shock, stent thrombosis and in-stent restenosis. A propensity score-adjusted Cox proportional-hazards model, which adjusted for traditional cardiovascular risk factors was predefined as the primary statistical model. Death at any time during the study period was pre-specified as primary end-point. RESULTS: During the study period 4.611 (65%) patients underwent primary PCI due to STEMI during off-hours and 2,525 (35%) during regular hours. The risk of dying was similar among the groups for the primary endpoint death at any time during the study period (HR 1.00, 95% CI 0.89-1.12, P = 0.991) and for secondary end-point death within 30 days (HR 1.03; 95% CI 0.85-1.25, P = 0.735). The risks of developing cardiogenic shock, stent thrombosis, or in-stent restenosis were similar between the groups. CONCLUSIONS: In our region, short- and long-term prognosis for patients with STEMI who undergo primary PCI is similar for patients presenting during off-hours and regular hours.