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Journal of Virology Oct 2022Cutaneous beta genus human papillomaviruses (β-HPVs) are suspected to promote the development of nonmelanoma skin cancer (NMSC) by destabilizing the host genome....
Cutaneous beta genus human papillomaviruses (β-HPVs) are suspected to promote the development of nonmelanoma skin cancer (NMSC) by destabilizing the host genome. Multiple studies have established the genome destabilizing capacities of β-HPV proteins E6 and E7 as a cofactor with UV. However, the E6 protein from β-HPV8 (HPV8 E6) induces tumors in mice without UV exposure. Here, we examined a UV-independent mechanism of HPV8 E6-induced genome destabilization. We showed that HPV8 E6 reduced the abundance of anaphase bridge resolving helicase, Bloom syndrome protein (BLM). The diminished BLM was associated with increased segregation errors and micronuclei. These HPV8 E6-induced micronuclei had disordered micronuclear envelopes but retained replication and transcription competence. HPV8 E6 decreased antiproliferative responses to micronuclei and time-lapse imaging revealed HPV8 E6 promoted cells with micronuclei to complete mitosis. Finally, whole-genome sequencing revealed that HPV8 E6 induced chromothripsis in nine chromosomes. These data provide insight into mechanisms by which HPV8 E6 induces genome instability independent of UV exposure. Some beta genus human papillomaviruses (β-HPVs) may promote skin carcinogenesis by inducing mutations in the host genome. Supporting this, the E6 protein from β-HPV8 (8 E6) promotes skin cancer in mice with or without UV exposure. Many mechanisms by which 8 E6 increases mutations caused by UV have been elucidated, but less is known about how 8 E6 induces mutations without UV. We address that knowledge gap by showing that 8 E6 causes mutations stemming from mitotic errors. Specifically, 8 E6 reduces the abundance of BLM, a helicase that resolves and prevents anaphase bridges. This hinders anaphase bridge resolution and increases their frequency. 8 E6 makes the micronuclei that can result from anaphase bridges more common. These micronuclei often have disrupted envelopes yet retain localization of nuclear-trafficked proteins. 8 E6 promotes the growth of cells with micronuclei and causes chromothripsis, a mutagenic process where hundreds to thousands of mutations occur in a chromosome.
Topics: Alphapapillomavirus; Animals; Chromothripsis; Genomic Instability; Mice; Nuclear Proteins; Oncogene Proteins, Viral; RecQ Helicases; Skin Neoplasms
PubMed: 36129261
DOI: 10.1128/jvi.01015-22 -
Clinical Case Reports Sep 2022Bloom syndrome patients often develop severe gastrointestinal symptoms mainly caused by gastric tumors due to DNA repair disorder. Here, we report 31-year-old Bloom...
Bloom syndrome patients often develop severe gastrointestinal symptoms mainly caused by gastric tumors due to DNA repair disorder. Here, we report 31-year-old Bloom syndrome patient suffering persistent abdominal pain due to refractory gastroduodenal ulcers which required gastroduodenectomy. Various causes should be considered, and the accumulation of their reports is warranted.
PubMed: 36110332
DOI: 10.1002/ccr3.6141 -
Resuscitation Plus Sep 2022Adrenaline is routinely administered during cardiac arrest resuscitation. Using a novel murine model of cardiac arrest, this study evaluates the effects of adrenaline...
BACKGROUND
Adrenaline is routinely administered during cardiac arrest resuscitation. Using a novel murine model of cardiac arrest, this study evaluates the effects of adrenaline use on survival and end-organ injury.
METHODS
A total of 58 mice, including cardiac arrest (CA) and sham (SHAM) groups received intravenous potassium chloride either as a bolus (CA) or slow infusion (SHAM), inducing ECG-confirmed asystole (in CA only) for 4-minutes prior to intravenous adrenaline (+ADR;250 ul,32 ug/ml) or saline (-ADR;250 ul) and manual chest compressions (300 BPM) for 4-minutes. Mice with return of spontaneous circulation (ROSC) were assessed at 24- or 72-h timepoints.
RESULTS
Among animals that underwent CA, rates of ROSC ( = 21 (95 %) vs = 14 (82 %), = 0.18) and survival to the planned endpoint ( = 11 (50 %) vs = 12 (71 %), = 0.19) were similar when comparing those treated with (CA+ADR) and without (CA-ADR) adrenaline. However, in CA animals that initially achieved ROSC, subsequent mortality was approximately 3-fold greater with adrenaline treatment (48 % vs 14 %, = 0.042). Among SHAM animals, adrenaline use had no impact on survival rates or other endpoints. Greater myocardial injury occurred in CA+ADR vs CA-ADR, with increased Hs-Troponin levels measured at 24- (26.0 ± 0.9 vs 9.4 ± 5.3 ng/mL, = 0.015) and 72-h (20.9 ± 8.3 vs 5.0 ± 2.4 ng/mL, = 0.012), associated with increased expression of pro-inflammatory and fibrotic genes within cardiac and renal tissue.
CONCLUSION
Adrenaline did not improve ROSC or overall survival but following successful ROSC, its use resulted in 3-fold greater mortality rates. Adrenaline was also associated with increased myocardial injury, end-organ inflammation, and fibrosis. These findings underscore the need for further preclinical evaluation of alternate pharmacologic adjuncts for cardiopulmonary resuscitation that improve survival and limit end-organ injury.
PubMed: 36059384
DOI: 10.1016/j.resplu.2022.100292 -
Molecular Medicine Reports Oct 2022Bloom syndrome protein (BLM) is known to maintain genomic integrity including DNA repair, recombination, replication and transcription. Its dysregulation affects the...
Bloom syndrome protein (BLM) is known to maintain genomic integrity including DNA repair, recombination, replication and transcription. Its dysregulation affects the genomic instability of cells, which results in a high risk of developing various types of cancer and even Bloom syndrome. However, to date, to the best of our knowledge, no association has been made between human BLM and bladder cancer. Thus, the aim of the present study was to investigate the role of BLM in human bladder cancer. The expression pattern of BLM in bladder cancer tissue was detected by immunohistochemistry. The viability, proliferation, cell cycle and apoptosis of bladder cancer cell lines were determined by Cell Counting Kit‑8, EdU and flow cytometry following transfection of BLM small interfering RNA. Finally, the effect of BLM on sensitivity of bladder cancer cell lines to cisplatin was investigated by reverse transcription‑quantitative PCR and western blot. It was demonstrated that the expression of BLM in human bladder cancer was increased compared with adjacent healthy bladder tissues. In addition, silencing of BLM inhibited the proliferation and promoted the apoptosis of bladder cancer cells and it also enhanced the sensitivity of bladder cancer cells to cisplatin. Together, the findings of the present study demonstrated that the regulation of BLM activity may have potential for use as a novel therapeutic target and a predictor for the prognosis of bladder cancer.
Topics: Apoptosis; Cell Proliferation; Cisplatin; Down-Regulation; Humans; RecQ Helicases; Urinary Bladder; Urinary Bladder Neoplasms
PubMed: 36004459
DOI: 10.3892/mmr.2022.12829 -
The Journal of Infectious Diseases Dec 2022The development of memory B cells after asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not well understood.
BACKGROUND
The development of memory B cells after asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is not well understood.
METHODS
We compared spike antibody titers, pseudovirus neutralizing antibody titers, and memory B-cell responses among SARS-CoV-2 PCR-positive Marine recruits who either reported asymptomatic or symptomatic infection.
RESULTS
Thirty-six asymptomatic participants exhibited similar spike IgG titers, spike IgA titers, and pseudovirus neutralization titers compared to 30 symptomatic participants. Pseudovirus neutralization and spike IgG titers showed significant positive correlations with frequency of memory B cells.
CONCLUSIONS
Among young adults, asymptomatic SARS-CoV-2 infection induced antibody and memory B-cell responses comparable to mild symptomatic infection.
Topics: Young Adult; Humans; COVID-19; SARS-CoV-2; Antibodies, Neutralizing; Antibodies, Viral; Immunoglobulin G; Spike Glycoprotein, Coronavirus
PubMed: 35892131
DOI: 10.1093/infdis/jiac319 -
Science (New York, N.Y.) Aug 2022To combat future severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global...
To combat future severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants and spillovers of SARS-like betacoronaviruses (sarbecoviruses) threatening global health, we designed mosaic nanoparticles that present randomly arranged sarbecovirus spike receptor-binding domains (RBDs) to elicit antibodies against epitopes that are conserved and relatively occluded rather than variable, immunodominant, and exposed. We compared immune responses elicited by mosaic-8 (SARS-CoV-2 and seven animal sarbecoviruses) and homotypic (only SARS-CoV-2) RBD nanoparticles in mice and macaques and observed stronger responses elicited by mosaic-8 to mismatched (not on nanoparticles) strains, including SARS-CoV and animal sarbecoviruses. Mosaic-8 immunization showed equivalent neutralization of SARS-CoV-2 variants, including Omicrons, and protected from SARS-CoV-2 and SARS-CoV challenges, whereas homotypic SARS-CoV-2 immunization protected only from SARS-CoV-2 challenge. Epitope mapping demonstrated increased targeting of conserved epitopes after mosaic-8 immunization. Together, these results suggest that mosaic-8 RBD nanoparticles could protect against SARS-CoV-2 variants and future sarbecovirus spillovers.
Topics: Animals; Antibodies, Neutralizing; Antibodies, Viral; Betacoronavirus; Coronavirus Infections; Disease Models, Animal; Epitopes; Macaca; Mice; Nanoparticles; Protein Domains; SARS-CoV-2; Spike Glycoprotein, Coronavirus; Zoonoses
PubMed: 35857620
DOI: 10.1126/science.abq0839 -
Frontiers in Molecular Biosciences 2022BLM is sumoylated in response to replication stress. We have studied the role of BLM sumoylation in physiologically normal and replication-stressed conditions by...
BLM is sumoylated in response to replication stress. We have studied the role of BLM sumoylation in physiologically normal and replication-stressed conditions by expressing in BLM-deficient cells a BLM with SUMO acceptor-site mutations, which we refer to as SUMO-mutant BLM cells. SUMO-mutant BLM cells exhibited multiple defects in both stressed and unstressed DNA replication conditions, including, in hydroxyurea-treated cells, reduced fork restart and increased fork collapse and, in untreated cells, slower fork velocity and increased fork instability as assayed by track-length asymmetry. We further showed by fluorescence recovery after photobleaching that SUMO-mutant BLM protein was less dynamic than normal BLM and comprised a higher immobile fraction at collapsed replication forks. BLM sumoylation has previously been linked to the recruitment of RAD51 to stressed forks in hydroxyurea-treated cells. An important unresolved question is whether the failure to efficiently recruit RAD51 is the explanation for replication stress in untreated SUMO-mutant BLM cells.
PubMed: 35847987
DOI: 10.3389/fmolb.2022.875102 -
Neurology. Genetics Aug 2022Topoisomerase III alpha plays a key role in the dissolution of double Holliday junctions and is required for mitochondrial DNA (mtDNA) replication and maintenance....
OBJECTIVES
Topoisomerase III alpha plays a key role in the dissolution of double Holliday junctions and is required for mitochondrial DNA (mtDNA) replication and maintenance. Sequence variants in the gene have been associated with the Bloom syndrome-like disorder and described in an adult patient with progressive external ophthalmoplegia. The purpose of this report is to expand the clinical phenotype of the -related diseases and clarify the role of this gene in primary mitochondrial disorders.
METHODS
A 44-year-old woman was referred to our hospital because of exercise intolerance and creatine kinase increase. Muscle biopsy and a targeted next-generation sequencing (NGS) analysis were performed.
RESULTS
A histopathologic assessment documented a mitochondrial myopathy, and a molecular analysis revealed a novel homozygous variant in the gene associated with multiple mtDNA deletions.
DISCUSSION
This case suggests that is one of the several nuclear genes associated with mtDNA maintenance disorder and expands the spectrum of its associated phenotypes, ranging from a clinical condition defined Bloom syndrome-like disorder to canonical mitochondrial syndromes.
PubMed: 35812164
DOI: 10.1212/NXG.0000000000200007 -
Virus Evolution 2022The long-term evolution of viruses is ultimately due to viral mutants that arise within infected individuals and transmit to other individuals. Here, we use deep...
The long-term evolution of viruses is ultimately due to viral mutants that arise within infected individuals and transmit to other individuals. Here, we use deep sequencing to investigate the transmission of viral genetic variation among individuals during a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak that infected the vast majority of crew members on a fishing boat. We deep-sequenced nasal swabs to characterize the within-host viral population of infected crew members, using experimental duplicates and strict computational filters to ensure accurate variant calling. We find that within-host viral diversity is low in infected crew members. The mutations that did fix in some crew members during the outbreak are not observed at detectable frequencies in any of the sampled crew members in which they are not fixed, suggesting that viral evolution involves occasional fixation of low-frequency mutations during transmission rather than persistent maintenance of within-host viral diversity. Overall, our results show that strong transmission bottlenecks dominate viral evolution even during a superspreading event with a very high attack rate.
PubMed: 35799885
DOI: 10.1093/ve/veac052