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Background: The American Optometric Association defines computer vision syndrome (CVS), also known as digital eye strain, as "a group of eye- and vision-related problems that result from prolonged computer, tablet, e-reader and cell phone use". We aimed to create a well-structured, valid, and reliable questionnaire to determine the prevalence of CVS, and to analyze the visual, ocular surface, and extraocular sequelae of CVS using a novel and smart self-assessment questionnaire. Methods: This multicenter, observational, cross-sectional, descriptive, survey-based, online study included 6853 complete online responses of medical students from 15 universities. All participants responded to the updated, online, fourth version of the CVS questionnaire (CVS-F4), which has high validity and reliability. CVS was diagnosed according to five basic diagnostic criteria (5DC) derived from the CVS-F4. Respondents who fulfilled the 5DC were considered CVS cases. The 5DC were then converted into a novel five-question self-assessment questionnaire designated as the CVS-Smart. Results: Of 10 000 invited medical students, 8006 responded to the CVS-F4 survey (80% response rate), while 6853 of the 8006 respondents provided complete online responses (85.6% completion rate). The overall CVS prevalence was 58.78% (n = 4028) among the study respondents; CVS prevalence was higher among women (65.87%) than among men (48.06%). Within the CVS group, the most common visual, ocular surface, and extraocular complaints were eye strain, dry eye, and neck/shoulder/back pain in 74.50% (n = 3001), 58.27% (n = 2347), and 80.52% (n = 3244) of CVS cases, respectively. Notably, 75.92% (3058/4028) of CVS cases were involved in the Mandated Computer System Use Program. Multivariate logistic regression analysis revealed that the two most statistically significant diagnostic criteria of the 5DC were ≥2 symptoms/attacks per month over the last 12 months (odds ratio [OR] = 204177.2; P <0.0001) and symptoms/attacks associated with screen use (OR = 16047.34; P <0.0001). The CVS-Smart demonstrated a Cronbach's alpha reliability coefficient of 0.860, Guttman split-half coefficient of 0.805, with perfect content and construct validity. A CVS-Smart score of 7-10 points indicated the presence of CVS. Conclusions: The visual, ocular surface, and extraocular diagnostic criteria for CVS constituted the basic components of CVS-Smart. CVS-Smart is a novel, valid, reliable, subjective instrument for determining CVS diagnosis and prevalence and may provide a tool for rapid periodic assessment and prognostication. Individuals with positive CVS-Smart results should consider modifying their lifestyles and screen styles and seeking the help of ophthalmologists and/or optometrists. Higher institutional authorities should consider revising the Mandated Computer System Use Program to avoid the long-term consequences of CVS among university students. Further research must compare CVS-Smart with other available metrics for CVS, such as the CVS questionnaire, to determine its test-retest reliability and to justify its widespread use.
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Established evidence indicates that oral microbiota plays a crucial role in modulating host immune responses to viral infection. Following severe acute respiratory syndrome coronavirus 2, there are coordinated microbiome and inflammatory responses within the mucosal and systemic compartments that are unknown. The specific roles the oral microbiota and inflammatory cytokines play in the pathogenesis of coronavirus disease 2019 (COVID-19) are yet to be explored. Here, we evaluated the relationships between the salivary microbiome and host parameters in different groups of COVID-19 severity based on their oxygen requirement. Saliva and blood samples (n = 80) were collected from COVID-19 and from noninfected individuals. We characterized the oral microbiomes using 16S ribosomal RNA gene sequencing and evaluated saliva and serum cytokines and chemokines using multiplex analysis. Alpha diversity of the salivary microbial community was negatively associated with COVID-19 severity, while diversity increased with health. Integrated cytokine evaluations of saliva and serum showed that the oral host response was distinct from the systemic response. The hierarchical classification of COVID-19 status and respiratory severity using multiple modalities separately (i.e. microbiome, salivary cytokines, and systemic cytokines) and simultaneously (i.e. multimodal perturbation analyses) revealed that the microbiome perturbation analysis was the most informative for predicting COVID-19 status and severity, followed by the multimodal. Our findings suggest that oral microbiome and salivary cytokines may be predictive of COVID-19 status and severity, whereas atypical local mucosal immune suppression and systemic hyperinflammation provide new cues to understand the pathogenesis in immunologically compromised populations.
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In previous studies, the inhibitory effect of chloroquine on NLRP3 inflammasome and heme production was documented. This may be employed as a double-bladed sword in schistosomiasis (anti-inflammatory and parasiticidal). In this study, chloroquine's impact on schistosomiasis mansoni was investigated. The parasitic load (worm/egg counts and reproductive capacity index [RCI]), i-Nos/Arg-1 expression, splenomegaly, hepatic insult and NLRP3-immunohistochemical expression were assessed in infected mice after receiving early and late repeated doses of chloroquine alone or dually with praziquantel. By early treatment, the least RCI was reported in dually treated mice (41.48 ± 28.58) with a significant reduction in worm/egg counts (3.50 ± 1.29/2550 ± 479.58), compared with either drug alone. A marked reduction in the splenic index was achieved by prolonged chloroquine administration (alone: 43.15 ± 5.67, dually: 36.03 ± 5.27), with significantly less fibrosis (15 ± 3.37, 14.25 ± 2.22) than after praziquantel alone (20.5 ± 2.65). Regarding inflammation, despite the praziquantel-induced significant decrease in NLRP3 expression, the inhibitory effect was marked after dual and chloroquine administration (liver: 3.13 ± 1.21/3.45 ± 1.23, spleen: 5.7 ± 1.6/4.63 ± 2.41). i-Nos RNA peaked with early/late chloroquine administration (liver: 68.53 ± 1.8/57.78 ± 7.14, spleen: 63.22 ± 2.06/62.5 ± 3.05). High i-Nos echoed with a parasiticidal and hepatoprotective effect and may indicate macrophage-1 polarisation. On the flip side, the chloroquine-induced low Arg-1 seemed to abate immune tolerance and probably macrophage-2 polarisation. Collectively, chloroquine synergised the praziquantel-schistosomicidal effect and minimised tissue inflammation, splenomegaly and hepatic fibrosis.
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Enfermedades de los Roedores , Esquistosomiasis mansoni , Animales , Ratones , Cloroquina/farmacología , Regulación hacia Abajo , Reposicionamiento de Medicamentos , Inflamación , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Carga de Parásitos , Praziquantel/farmacología , Esquistosomiasis mansoni/tratamiento farmacológico , EsplenomegaliaRESUMEN
BACKGROUND: Soybean mosaic virus (SMV) is a devastating disease that threatens soybean plants worldwide. The different soybean genotypes displayed different responses to SMV strains. This study aimed to investigate the response of different selected soybean cultivars to SMV infection in Egypt based on their specific genetic makeup. RESULT: The symptoms of SMV infection and the viral concentration were evaluated in eight soybean cultivars (Giza 21, Giza 22, Giza 35, Giza 82, Giza 111, Crawford, H4L4, and PI416937) using ELISA assay. The results indicated that Giza 21 and Giza 35 were moderately tolerant to SMV infection, while Giza 82 was the least tolerant cultivar. Giza 22, Giza 111, and PI416937 were less tolerant; however, H4L4 and Crawford were identified as the most tolerant cultivars against SMV infection. The chi-square analysis showed a significant association between the different selected cultivars and their response against SMV infection. The PCR test showed the presence of RSV1 (3gG2), RSV1 (5gG3), and RSV3 loci, and the absence of the RSV4 locus gene. The expression analysis of the selected defense genes (EDS1, PAD4, EDR1, ERF1, and JAR) showed variations in the fold changes between infected and non-infected soybean cultivars, suggesting that these genes might play a crucial role in this pathosystem. Additionally, there was a strong positive association between the expression levels of EDR1 and ERF1. CONCLUSION: The study found the presence of RSV1 (3gG2), RSV1 (5gG3), and RSV3 loci in selected soybean cultivars, but not RSV4. The analysis of gene expression indicated that certain defense genes may play a vital role in the pathosystem. This research is the first of its kind in Egypt to genotype soybean cultivars regarding different RSV loci. The findings could be beneficial for further research on understanding the molecular mechanisms involved in SMV infection and its management.
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Despite extensive research to decipher the immunological basis of coronavirus disease (COVID-19), limited evidence on immunological correlates of COVID-19 severity from MENA region and Egypt was reported. In a single-center cross-sectional study, we have analyzed 25 cytokines that are related to immunopathologic lung injury, cytokine storm, and coagulopathy in plasma samples from 78 hospitalized Egyptian COVID-19 patients in Tanta University Quarantine Hospital and 21 healthy control volunteers between April 2020 and September 2020. The enrolled patients were divided into 4 categories based on disease severity, namely mild, moderate, severe, and critically ill. Interestingly, interleukin (IL)-1-α, IL-2Rα, IL-6, IL-8, IL-18, tumor necrosis factor-alpha (TNF-α), FGF1, CCL2, and CXC10 levels were significantly altered in severe and/or critically ill patients. Moreover, principal component analysis (PCA) demonstrated that severe and critically ill COVID-19 patients cluster based on specific cytokine signatures that distinguish them from mild and moderate COVID-19 patients. Specifically, levels of IL-2Rα, IL-6, IL-10, IL-18, TNF-α, FGF1, and CXCL10 largely contribute to the observed differences between early and late stages of COVID-19 disease. Our PCA showed that the described immunological markers positively correlate with high D-dimer and C-reactive protein levels and inversely correlate with lymphocyte counts in severe and critically ill patients. These data suggest a disordered immune regulation, particularly in severe and critically ill Egyptian COVID-19 patients, manifested as overactivated innate immune and dysregulated T-helper1 responses. Additionally, our study emphasizes the importance of cytokine profiling to identify potentially predictive immunological signatures of COVID-19 disease severity.
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COVID-19 , Citocinas , Humanos , Interleucina-18 , Estudios Transversales , Egipto , Interleucina-6 , Factor de Necrosis Tumoral alfa , Enfermedad Crítica , Subunidad alfa del Receptor de Interleucina-2 , Factor 1 de Crecimiento de Fibroblastos , Gravedad del PacienteRESUMEN
Established evidence indicates that oral microbiota plays a crucial role in modulating host immune responses to viral infection. Following Severe Acute Respiratory Syndrome Coronavirus 2 - SARS-CoV-2 - there are coordinated microbiome and inflammatory responses within the mucosal and systemic compartments that are unknown. The specific roles that the oral microbiota and inflammatory cytokines play in the pathogenesis of COVID-19 are yet to be explored. We evaluated the relationships between the salivary microbiome and host parameters in different groups of COVID-19 severity based on their Oxygen requirement. Saliva and blood samples (n = 80) were collected from COVID-19 and from non-infected individuals. We characterized the oral microbiomes using 16S ribosomal RNA gene sequencing and evaluated saliva and serum cytokines using Luminex multiplex analysis. Alpha diversity of the salivary microbial community was negatively associated with COVID-19 severity. Integrated cytokine evaluations of saliva and serum showed that the oral host response was distinct from the systemic response. The hierarchical classification of COVID-19 status and respiratory severity using multiple modalities separately (i.e., microbiome, salivary cytokines, and systemic cytokines) and simultaneously (i.e., multi-modal perturbation analyses) revealed that the microbiome perturbation analysis was the most informative for predicting COVID-19 status and severity, followed by the multi-modal. Our findings suggest that oral microbiome and salivary cytokines may be predictive of COVID-19 status and severity, whereas atypical local mucosal immune suppression and systemic hyperinflammation provide new cues to understand the pathogenesis in immunologically naïve populations.
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Collodion baby is a rare congenital disorder and a very intense disorder in which the baby suffers from several complications, such as trans-epidermal water loss. Only â¼270 cases of collodion babies have been reported in the literature since 1892. This disease may later develop one of a spectrum of diseases including lamellar ichthyosis, which the patient may had Congenital lamellar ichthyosis with ectropion, which was clinically distinguished by the collodion baby phenotype at birth. Case presentation: The authors are reporting the first case in Syria, a 20-day-old white Syrian male newborn, vaginally delivered at 38 weeks of pregnancy, with normal conditions, and congenital lamellar ichthyosis was shown by physical examination, as parchment-like scales were covering the newborn's skin, which was starting to detach and showing the "collodion baby" appearance. Ophthalmologic examination revealed a bilateral ectropion of the upper eyelids with tarsal eversion. A treatment of Tobramycin 0.3% eye ointment was prescribed four times a day, with a viscotears liquid gel eye drops 4 times a day, and vaseline petroleum jelly to be applied three times daily. At 2-month follow-up, a significant improvement was noted. Conclusion: Ichthyosis have a wide range of disorders that involve the skin and have inherited and acquired forms. As a result, keratolytic and systemic retinoids can have significant benefits in restoring skin function.
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The magnification technique offered by surgical loupe is a new method that enhances visualization and helps head and neck surgeons with recurrent laryngeal nerve (RLN) and parathyroid glands identification. This study aimed to assess the safety and efficacy of using binocular surgical loupes in thyroidectomy procedures. Material and Methods: Eighty patients with thyroid nodules who underwent thyroidectomy procedure were divided randomly into two comparable groups, group A subjected to thyroidectomy by using binocular magnification loupe, group B underwent conventional thyroidectomy without using magnification. Patients' demographics, operation time, and postoperative morbidities were recorded. All cases had preoperative and postoperative vocal cords assessment by video laryngoscopy. Pathology, laboratory, and radiology investigations were also conducted. Results: Out of 80 patients, there were 58 females and 22 males. Benign thyroid pathology was found in 74 patients and malignant pathology in 6 patients. The mean operating time was 106 min in group A compared to 138.5 min in group B. The mean amount of intraoperative bleeding was 30 ml in group A while 50 ml in group B. There were no cases of the external branch of the superior laryngeal nerve in both groups; there was better identification in group A. There was only one patient who suffered from a temporary RLN injury in group A, while three cases of temporary and one case of permanent RLN injury were recorded in group B. Permanent hypoparathyroidism was diagnosed in only one patient in group B. Conclusion: The utilization of binocular surgical loupe magnification in thyroid surgery is considered a safe and effective maneuver that has the advantages of decreasing the overall operating time and significantly reducing postoperative complications.
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Sildenafil is a medication used for the treatment of erectile dysfunction. It was approved by the U.S. Food and Drug Administration (FDA) in 1998. Several articles have raised concerns regarding the use of sildenafil and the occurrence of serious adverse events, such as myocardial ischemia, stroke, and even death. Our aim is to systematically review the existing literature on mortality associated with sildenafil use. The method used for this systematic review was completed by searching three databases: PubMed, Scopus, and Web of Science. Articles were screened and assessed for eligibility. This review uses the articles found to address the concerns associated with sildenafil and mortality. A total of 19 reports were used in our systematic review, in which there were 10 case reports, two case series, three systematic reviews, one narrative review, one retrospective study, one article in the British Medical Journal, and one commentary article. One FDA article in particular included case reports and reports to the FDA on the use of sildenafil eight months after its introduction to the market in 1998, with 522 deaths reported. Another retrospective study examined the use of sildenafil on infants below the age of 1 who did not have congenital heart disease but did suffer from severe pulmonary hypertension. The study found a mortality rate of 29%, which increased with sildenafil dosage. A case series examined six deaths related to non-prescription use of sildenafil. All these cases were subjected to autopsies and related to sexual activity. The study suggests that phosphodiesterase 5 inhibitors induced the deaths, and the concentration of sildenafil in the femoral blood was found to be between 0.032and0.087 µg. To conclude, the literature available on this topic is deemed insufficient to provide enough data to establish a direct link of causality between sildenafil and mortality. Although some studies paint sildenafil as the culprit behind these deaths, further studies and research are needed to explain the unexpected deaths following sildenafil use.
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Background: Recent studies reported a long-lasting effect of COVID-19 infection that extends beyond the active disease and disrupts various body systems besides the respiratory system. The current study aims to investigate the post-acute effect of SARS-CoV-2 infection on cardiovascular autonomic activity, reactivity and sensitivity in patients who had the infection at least 3 months before. Methods: This was a comparative cross-sectional observational study. Fifty-nine subjects were allocated into two groups, controls (n=31), who had no history of positive COVID-19 infection, and the post-COVID patients (n=28) who were recruited 3 to 8 months after testing positive for SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR). Baseline cardiovascular autonomic activity was evaluated through recording of baseline heart rate variability (HRV), autonomic reactivity was determined through standard cardiovascular autonomic reflex tests (CART), and cardiac autonomic sensitivity was assessed through cardiac baroreceptor sensitivity (cBRS). Results: Higher incidence of orthostatic hypotension was observed in post-COVID patients compared to controls (39.3% and 3.2%, respectively, p <0.001). Additionally, significantly reduced handgrip test, and heart rate response to head-up tilt was illustrated in the post-COVID group (p <0.001). About 85.7% of post-COVID participants had at least one abnormal cardiovascular reflex test (CART) compared to the control group (p <0.001). Although HRV parameters (TP, LF, HF, SDRR, RMSSD, pRR50), and the cBRS were numerically lower in the post-COVID-19 group, this did not reach the level of significance. Conclusion: The results of the present study are suggestive of altered cardiovascular reactivity in post-acute COVID patients and demand further investigation and longer term follow up.
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BACKGROUND: Bariatric surgical operation is taken into consideration to be the handiest remedy for extreme obesity. Durability is the main requirement for the broad usage of bariatric surgery. According to several factors, the present work tries to match the SG and RYGB techniques. METHODS: This is a retrospective work that studied 200 morbid obese patients randomized and categorized into two groups according to the treatment method: the laparoscopic sleeve gastrectomy (LSG) and LRYGB groups, within the period from 2014 to 2019 and matched weight dissipation, complications, quality of life, and adverse events. RESULTS: BMI had a mean value of 39.66 ± 3.770 kg/m2 in the RYGB group versus 39.38 ± 3.648 kg/m2. No significant differences were found according to comorbidity, height, and weight. There was no significant difference between the study groups according to complications and morbidity-no recorded unexpected histopathology results in the excised LSG specimens. CONCLUSION: There was no significant change in weight dissipation, fluctuations in comorbidities, increase in Quality of Life (QoL), and complications for pathological obesity patients according to the treatment methods of laparoscopic SG (sleeve gastrectomy) and RYGB at 2-years postoperative follow-up.
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BACKGROUND: Further reports are required to describe the outcome of truncal dystonia treated by bilateral pallidal stimulation (globus pallidus interna deep brain stimulation [GPi-DBS]), owing to the small number of reports and clinical variability and complexity of truncal dystonia. Retrospectively, we report our experience of treating three patients with idiopathic generalized dystonia, with predominant mobile truncal dystonia by bilateral GPi-DBS. METHODS: Three patients with idiopathic generalized dystonia underwent bilateral GPi-DBS. One patient had adult-onset dystonia, while two patients had childhood-onset dystonia. All patients had predominant mobile truncal dystonia of mixed abnormal postures (camptocormia and lateral tilt), while one patient had also truncal twist. Patients were assessed pre- and post-GPi-DBS using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Dystonia Disability Scale (DDS). RESULTS: The three patients showed marked improvement of global (94.78%, 92.4% and 80.95%) and truncal BFMDRS (all abnormal postures) (87.5%, 93.75% and 87.5%) and DDS (95.84% and 50%), using high amplitude monopolar settings, with a dramatic improvement of the mobile component. Improvement was persistent for 1.5, 3 and 6 years. CONCLUSION: Bilateral GPi-DBS improves markedly the mobile truncal dystonia and associated abnormal postures in patients with adult and childhood-onset idiopathic generalized dystonia. Improvement was persistent for up to 6 years.
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Estimulación Encefálica Profunda , Distonía , Trastornos Distónicos , Trastornos del Movimiento , Adulto , Niño , Distonía/terapia , Trastornos Distónicos/terapia , Globo Pálido/fisiología , Humanos , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
Zinc finger protein St18 was initially reported as candidate tumor suppressor gene, and also suggested that fibroblast St18 positively regulates NF-κB activation. Despite the pleiotropic functions of St18, little is known about its roles in macrophages. Here, we report that myeloid St18 is a potent inhibitor of VEGF-A. Mice lacking St18 in myeloid lineages exhibit increased retinal vasculature with enhanced serum VEGF-A concentrations. Despite the normal activation of NF-κB target genes, these mice are highly susceptible to LPS-induced shock, polymicrobial sepsis, and experimental colitis, accompanied by enhanced vascular and intestinal leakage. Pharmacological inhibition of VEGF signaling rescued the high mortality rate of myeloid-specific St18-deficient mice in response to inflammation. Mechanistically, St18 directly binds to Sp1 and attenuates its activity, leading to the suppression of Sp1 target gene VEGF-A. Using mouse genetic and pharmacological models, we reveal myeloid St18 as a critical septic death protector.
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Macrófagos/metabolismo , Proteínas Represoras/metabolismo , Sepsis/patología , Sepsis/prevención & control , Factor A de Crecimiento Endotelial Vascular/antagonistas & inhibidores , Dedos de Zinc , Animales , Ciego/patología , Linaje de la Célula , Colitis/complicaciones , Colitis/patología , Sulfato de Dextran , Susceptibilidad a Enfermedades , Regulación de la Expresión Génica , Inflamación/patología , Ligadura , Lipopolisacáridos , Macrófagos/patología , Ratones , Ratones Endogámicos C57BL , Células Mieloides/metabolismo , FN-kappa B/metabolismo , Punciones , Células RAW 264.7 , Proteínas Represoras/deficiencia , Sepsis/complicaciones , Choque Séptico/microbiología , Choque Séptico/patología , Transducción de Señal , Factor de Transcripción Sp1/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Background: Neonatal sepsis syndrome continues to have a high morbidity and mortality rate despite the progress in neonatal intensive care. There is no single diagnostic test which can reliably diagnose sepsis in the newborn, beside blood culture. Antithrombin III may be one promising single marker for sepsis syndrome diagnosis and prognosis. Methods: We quantitated antithrombin III (ATIII) in neonates with sepsis syndrome and compared these levels to healthy controls. Results: ATIII levels were significantly lower in sepsis syndrome neonates (23.05 ± 3.66) compared to controls (35.50 ± 2.50), (p < 0.001). ROC curve for ATIII displayed area under the curve of 0.973, cutoff >30 mg/dL, a positive predictive value 90.47 and negative predictive value 96.55. Conclusion: Antithrombin III is lower in sepsis syndrome neonates and may be a useful biomarker in neonatal sepsis.
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Antitrombina III/análisis , Sepsis Neonatal/sangre , Síndrome de Respuesta Inflamatoria Sistémica/sangre , Algoritmos , Área Bajo la Curva , Biomarcadores/sangre , Estudios de Casos y Controles , Femenino , Humanos , Recién Nacido , Recién Nacido de muy Bajo Peso , Cuidado Intensivo Neonatal , Masculino , Tamizaje Neonatal , Sepsis Neonatal/diagnóstico , Pronóstico , Curva ROC , Síndrome de Respuesta Inflamatoria Sistémica/diagnósticoRESUMEN
Immunoglobulin affinity maturation depends on somatic hypermutation (SHM) in immunoglobulin variable (IgV) regions initiated by activation-induced cytidine deaminase (AID). AID induces transition mutations by CâU deamination on both strands, causing C:GâT:A. Error-prone repairs of U by base excision and mismatch repairs (MMRs) create transversion mutations at C/G and mutations at A/T sites. In Neuberger's model, it remained to be clarified how transition/transversion repair is regulated. We investigate the role of AID-interacting GANP (germinal center-associated nuclear protein) in the IgV SHM profile. GANP enhances transition mutation of the non-transcribed strand G and reduces mutation at A, restricted to GYW of the AID hotspot motif. It reduces DNA polymerase η hotspot mutations associated with MMRs followed by uracil-DNA glycosylase. Mutation comparison between IgV complementary and framework regions (FWRs) by Bayesian statistical estimation demonstrates that GANP supports the preservation of IgV FWR genomic sequences. GANP works to maintain antibody structure by reducing drastic changes in the IgV FWR in affinity maturation.
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Linfocitos B/inmunología , Centro Germinal/inmunología , Región Variable de Inmunoglobulina/genética , Mutación/genética , Proteínas Nucleares/genética , Fosfoproteínas/genética , Animales , Afinidad de Anticuerpos , Teorema de Bayes , Células Cultivadas , Citidina Desaminasa/metabolismo , Reparación del ADN , Región Variable de Inmunoglobulina/metabolismo , Ratones , Ratones Noqueados , Proteínas Nucleares/metabolismo , Fosfoproteínas/metabolismo , Conformación Proteica , Hipermutación Somática de InmunoglobulinaRESUMEN
RNA export factor germinal center-associated nuclear protein (GANP) interacts with activation-induced cytidine deaminase (AID) and shepherds it from the cytoplasm to the nucleus and toward the IgV region loci in B cells. In this study, we demonstrate a role for GANP in the repair of AID-initiated DNA damage in chicken DT40 B cells to generate IgV region diversity by gene conversion and somatic hypermutation. GANP plays a positive role in IgV region diversification of DT40 B cells in a nonhomologous end joining-proficient state. DNA-PKcs physically interacts with GANP, and this interaction is dissociated by dsDNA breaks induced by a topoisomerase II inhibitor, etoposide, or AID overexpression. GANP affects the choice of DNA repair mechanism in B cells toward homologous recombination rather than nonhomologous end joining repair. Thus, GANP presumably plays a critical role in protection of the rearranged IgV loci by favoring homologous recombination of the DNA breaks under accelerated AID recruitment.
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Citidina Desaminasa/inmunología , Reparación del ADN/inmunología , Proteína Quinasa Activada por ADN/inmunología , Proteínas de Unión al ADN/inmunología , Región Variable de Inmunoglobulina/inmunología , Proteínas Nucleares/inmunología , Fosfoproteínas/inmunología , Hipermutación Somática de Inmunoglobulina/inmunología , Animales , Linfocitos B/inmunología , Citidina Desaminasa/genética , Reparación del ADN/genética , Proteína Quinasa Activada por ADN/genética , Proteínas de Unión al ADN/genética , Sitios Genéticos/inmunología , Región Variable de Inmunoglobulina/genética , Ratones , Ratones Noqueados , Proteínas Nucleares/genética , Fosfoproteínas/genética , Hipermutación Somática de Inmunoglobulina/genéticaRESUMEN
The ssDNA-dependent deoxycytidine deaminase apolipoprotein B mRNA-editing, enzyme-catalytic, polypeptide-like 3G (A3G) is a potent restrictive factor against HIV-1 virus lacking viral-encoded infectivity factor (Vif) in CD4(+) T cells. A3G antiretroviral activity requires its encapsulation into HIV-1 virions. In this study, we show that germinal center-associated nuclear protein (GANP) is induced in activated CD4(+) T cells and physically interacts with A3G. Overexpression of GANP augments the A3G encapsidation into the virion-like particles and ΔVif HIV-1 virions. GANP is encapsidated in HIV-1 virion and modulates A3G packaging into the cores together with cellular RNAs, including 7SL RNA, and with unspliced HIV-1 genomic RNA. GANP upregulation leads to a significant increase in A3G-catalyzed GâA hypermutation in the viral genome and suppression of HIV-1 infectivity in a single-round viral infection assay. Conversely, GANP knockdown caused a marked increase in HIV-1 infectivity in a multiple-round infection assay. The data suggest that GANP is a cellular factor that facilitates A3G encapsidation into HIV-1 virions to inhibit viral infectivity.
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Acetiltransferasas/fisiología , Linfocitos T CD4-Positivos/inmunología , Citidina Desaminasa/fisiología , VIH-1/fisiología , Péptidos y Proteínas de Señalización Intracelular/fisiología , Virión/metabolismo , Desaminasa APOBEC-3G , Acetiltransferasas/antagonistas & inhibidores , Acetiltransferasas/biosíntesis , Acetiltransferasas/química , Acetiltransferasas/genética , Células Cultivadas , Citidina Desaminasa/química , Genes vif , VIH-1/ultraestructura , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/biosíntesis , Péptidos y Proteínas de Señalización Intracelular/química , Péptidos y Proteínas de Señalización Intracelular/genética , Activación de Linfocitos , Mutación , Mapeo de Interacción de Proteínas , ARN Mensajero/biosíntesis , ARN Mensajero/genética , ARN Citoplasmático Pequeño/metabolismo , ARN Interferente Pequeño/farmacología , ARN Viral/genética , ARN Viral/metabolismo , Partícula de Reconocimiento de Señal/metabolismo , Regulación hacia Arriba , Virión/ultraestructura , Virulencia , Replicación Viral , Productos del Gen vif del Virus de la Inmunodeficiencia Humana/deficiencia , ARN Pequeño no TraducidoRESUMEN
Somatic hypermutation in B cells is initiated by activation-induced cytidine deaminase-catalyzed CâU deamination at immunoglobulin variable regions. Here we investigate the role of the germinal centre-associated nuclear protein (GANP) in enhancing the access of activation-induced cytidine deaminase (AID) to immunoglobulin variable regions. We show that the nuclear export factor GANP is involved in chromatin modification at rearranged immunoglobulin variable loci, and its activity requires a histone acetyltransferase domain. GANP interacts with the transcription stalling protein Spt5 and facilitates RNA Pol-II recruitment to immunoglobulin variable regions. Germinal centre B cells from ganp-transgenic mice showed a higher AID occupancy at the immunoglobulin variable region, whereas B cells from conditional ganp-knockout mice exhibit a lower AID accessibility. These findings suggest that GANP-mediated chromatin modification promotes transcription complex recruitment and positioning at immunoglobulin variable loci to favour AID targeting.