Membrane-Associated Ubiquitin Ligase RING Finger Protein 152 Orchestrates Melanogenesis via Tyrosinase Ubiquitination

Lysosomal degradation of tyrosinase, a pivotal enzyme in melanin synthesis, negatively impacts melanogenesis in melanocytes. Nevertheless, the precise molecular mechanisms by which lysosomes target tyrosinase have remained elusive. Here, we identify RING (Really Interesting New Gene) finger protein 152 (RNF152) as a membrane-associated ubiquitin ligase specifically targeting tyrosinase for the first time, utilizing AlphaScreen technology. We observed that modulating RNF152 levels in B16 cells, either via overexpression or siRNA knockdown, resulted in decreased or increased levels of both tyrosinase and melanin, respectively. Notably, RNF152 and tyrosinase co-localized at the trans-Golgi network (TGN). However, upon treatment with lysosomal inhibitors, both proteins appeared in the lysosomes, indicating that tyrosinase undergoes RNF152-mediated lysosomal degradation. Through ubiquitination assays, we found the indispensable roles of both the RING and transmembrane (TM) domains of RNF152 in facilitating tyrosinase ubiquitination. In summary, our findings underscore RNF152 as a tyrosinase-specific ubiquitin ligase essential for regulating melanogenesis in melanocytes.

SRPKIN-1 as an inhibitor against hepatitis B virus blocking the viral particle formation and the early step of the viral infection

New antiviral agents are needed for the treatment of hepatitis B virus (HBV) infection because currently available drugs do not completely eradicate chronic HBV in patients. Phosphorylation dynamics of the HBV core protein (HBc) regulate several processes in the HBV life cycle, including nucleocapsid formation, cell trafficking, and virus uncoating after entry. In this study, the SRPK inhibitors SPHINX31, SRPIN340, and SRPKIN-1 showed concentration-dependent anti-HBV activity. Detailed analysis of the effects of SRPKIN-1, which exhibited the strongest inhibitory activity, on the HBV replication process showed that it inhibits the formation of infectious particles by inhibiting pregenomic RNA packaging into capsids and nucleocapsid envelopment. Mass spectrometry analysis combined with cell-free translation system experiments revealed that hyperphosphorylation of the C-terminal domain of HBc is inhibited by SRPKIN-1. Further, SRPKIN-1 exhibited concentration-dependent inhibition of HBV infection not only in HepG2-hNTCP-C4 cells but also in fresh human hepatocytes (PXB cells) and in the single-round infection system. Treatment with SRPKIN-1 at the time of infection reduced the nuclease sensitivity of HBV DNA in the nuclear fraction. These results suggest that SRPKIN-1 has the potential to not only inhibit the HBV particle formation process but also impair the early stages of viral infection.

Wnt activation disturbs cell competition and causes diffuse invasion of transformed cells through NF-κB-MMP21 pathway

Normal epithelial cells exert their competitive advantage over RasV12-transformed cells and eliminate them into the apical lumen via cell competition. However, the internal or external factors that compromise cell competition and provoke carcinogenesis remain elusive. In this study, we examine the effect of sequential accumulation of gene mutations, mimicking multi-sequential carcinogenesis on RasV12-induced cell competition in intestinal epithelial tissues. Consequently, we find that the directionality of RasV12-cell extrusion in Wnt-activated epithelia is reversed, and transformed cells are delaminated into the basal lamina via non-cell autonomous MMP21 upregulation. Subsequently, diffusively infiltrating, transformed cells develop into highly invasive carcinomas. The elevated production of MMP21 is elicited partly through NF-κB signaling, blockage of which restores apical elimination of RasV12 cells. We further demonstrate that the NF-κB-MMP21 axis is significantly bolstered in early colorectal carcinoma in humans. Collectively, this study shows that cells with high mutational burdens exploit cell competition for their benefit by behaving as unfit cells, endowing them with an invasion advantage.

A strategy for orthogonal deubiquitination using a bump-and-hole approach

We have successfully applied a bump-and-hole approach to establish orthogonal deubiquitination in which a ubiquitin substrate variant is specifically targeted by an engineered deubiquitinating enzyme (DUB). This makes it possibe to selectively observe and measure a single type of DUB activity in living cells.

The E3 ligase DTX2 inhibits RUNX1 function by binding its C terminus and prevents the growth of RUNX1-dependent leukemia cells

Transcription factor RUNX1 plays important roles in hematopoiesis and leukemogenesis. RUNX1 function is tightly controlled through posttranslational modifications, including ubiquitination and acetylation. However, its regulation via ubiquitination, especially proteasome-independent ubiquitination, is poorly understood. We previously identified DTX2 as a RUNX1-interacting E3 ligase using a cell-free AlphaScreen assay. In this study, we examined whether DTX2 is involved in the regulation of RUNX1 using in vitro and ex vivo analyses. DTX2 bound to RUNX1 and other RUNX family members RUNX2 and RUNX3 through their C-terminal region. DTX2-induced RUNX1 ubiquitination did not result in RUNX1 protein degradation. Instead, we found that the acetylation of RUNX1, which is known to enhance the transcriptional activity of RUNX1, was inhibited in the presence of DTX2. Concomitantly, DTX2 reduced the RUNX1-induced activation of an MCSFR luciferase reporter. We also found that DTX2 induced RUNX1 cytoplasmic mislocalization. Moreover, DTX2 overexpression showed a substantial growth-inhibitory effect in RUNX1-dependent leukemia cell lines. Thus, our findings indicate a novel aspect of the ubiquitination and acetylation of RUNX1 that is modulated by DTX2 in a proteosome-independent manner.

Long-Term Outcomes in a Phase II Study of Hypofractionated IGRT 60Gy/ 20F in Patients with Isolated Lymph Node Recurrence after Surgery for Esophageal Carcinoma

PURPOSE/OBJECTIVE(S)

In oligo metastases in lymph node recurrence after surgery for esophageal cancer, since SBRT (BED>100 Gy10) to mediastinal and abdominal lymph node lesions was not an option due to toxicities in the organs at risk (OAR) such as vessels and gastrointestinal tract, we performed a prospective cohort study of hypofractionated IGRT for isolated lesions. The primary end-points of this study are disease specific survival (DSS) and late treatment toxicities.

MATERIALS/METHODS

From 2011 to 2021, 60 Gy/20F/4-4.5wks (78 Gy10) hypofractionated IGRT was performed in a total ITT population of 70 patients after radical surgery (67 cases) and ESD (3 cases), who were diagnosed by CT/PET-CT as having solitary lymph node recurrence (62 cases) or up to 2 adjacent nodes (8 cases). The mean time from surgery to recurrence was 17.9 months (SD 18.1) with a mean age of 67.5 years (SD 9.3), and male to female ratio was 62:8. Pathological results showed that 63 patients (90%) had squamous cell carcinoma. The mean maximum diameter of lesions was 2.5 cm (SD; 1.1 cm). And 51 cases (73%) were treated with CRT concurrently using 5FU plus CDDP (FP), and the rest were treated with RT alone. Lymph node location was lower neck or upper mediastinum in 42 cases, middle and lower mediastinum in 16 cases, and abdomen in 12 cases, respectively. Treatment planning was performed by taking 4DCT fusing PET or MRI images. The Kaplan-Meier method and the Cox proportional hazards regression model were used for overall survival (OS), DSS, and progression free survival (PFS).

RESULTS

The mean observation period was 38 months. Primary efficacy was CR in 45 cases (64%), but CR was maintained only in 29 cases (41%). Twenty-two of the 70 patients were relapse-free. OS were 53% and 34% at 2 and 5 years, DSS were 56% and 38% at 2 and 5 years, and PFS were 40% and 39% at 2 and 5 years, respectively. The site of first recurrence was the same or adjacent lymph nodes in 33 cases (47%) and distant metastases in 9 cases (13%). Number of tumors (1 vs. 2), age, and CRT were not significant prognostic factors for OS, DSS, or PFS. In a multivariate analysis, the time from surgery to recurrence ≥12 months was the only significant prognostic factor for PFS (p = 0.018, HR0.50). The same multivariate analysis showed that the only significant prognostic factor for DSS was the location of the recurrent lymph node in the neck and upper mediastinal regions (p = 0.009, HR 0.59). The only late adverse events of Grade 2 or higher were Grade 2 pleural effusion (little and transient) in 6 cases and Grade 2 radiation pneumonitis in 1 case. No acute adverse events were observed other than hematologic toxicity due to FP administration.

CONCLUSION

In locally advanced esophageal cancer, a relatively reliable regional lymph node dissection is often performed, so there is still a chance to aim for cure in cases of solitary recurrence. We found that if the lesion is solitary, localized RT of about 60 Gy/20F/4-4.5 weeks with IGRT can achieve a long-term survival in 40% of patients without any significant adverse events.

Health-Related Quality of Life at Five Years for a Randomized Trial of Tri-Modality Therapy with I-125 Brachytherapy, External Beam Radiation Therapy, and Short- vs. Long-Term Androgen Deprivation Therapy for High-Risk Localized Prostate Cancer (TRIP)

PURPOSE/OBJECTIVE(S)

To describe the patient-reported health-related quality of life (HR-QoL) outcomes at five years for a multicenter randomized trial of tri-modality therapy with iodine-125 brachytherapy, external beam radiation therapy (EBRT), and short- versus long-term androgen deprivation therapy (ADT) for high-risk localized prostate cancer (TRIP/TRIGU0907).

MATERIALS/METHODS

A total of 332 men with high-risk prostate cancer were randomized to either 6 months of ADT (n = 165) or 30 months of ADT (n = 167) in conjunction with combined modality radiation therapy. For the HR-QoL assessment, general HR-QoL and disease-specific HR-QoL were measured using the Japanese version of the Medical Outcomes Study 8-items Short-Form Health Survey (SF-8) and the Expanded Prostate Cancer Index Composite (EPIC). Patient-reported outcome questionnaires were filled out before ADT initiation, and five years after. Scores were reported as mean with the standard deviation. QoL end points were assessed as the change between pre and post treatment using paired student t-test. Changes in the International Prostate Symptom Scores (IPSS) score, including total score and subscores, were also evaluated. The study was powered according to the primary endpoint of biochemical progression free survival with HR-QoL as a secondary endpoint. In addition, recovery of testosterone level (300ng/dL or higher) was calculated as the cumulative incidence curve and compared between arms by log-rank test.

RESULTS

The cumulative incidence of biochemical progression, and salvage ADT treatment were not different between the arms. Mean domain scores at baseline were well balanced between the two arms in all HR-QoL. There were no differences in the SF-8 assessment and the total and subscore EPIC assessments between the arms. The average sexual function score was lower in short arm versus long arm; 16.24 versus 20.24 at baseline, but not different at five years, 9.96 versus 7.78 (p = 0.164). There were no significant differences between the arms for the total and subscore IPSS. Significantly higher percentage of patients, 71.7% in the short arm recovered to a normal testosterone level at 6 years after the initiation of ADT compared to 43.2% in long arm (p<0.0001).

CONCLUSION

At five years after ADT initiation, there were no significant differences in all score changes between the two arms with general HR-QoL and disease-specific HR-QoL. Most of HR-QoL returned to baseline level, and sexual function scores were low from baseline in this population. Two-years' adjuvant ADT did not affect HR-QoL at five years, although it significantly retarded testosterone recovery compared to 6 months of hormone therapy.

Role of hepcidin upregulation and proteolytic cleavage of ferroportin 1 in hepatitis C virus-induced iron accumulation

Hepatitis C virus (HCV) is a pathogen characterized not only by its persistent infection leading to the development of cirrhosis and hepatocellular carcinoma (HCC), but also by metabolic disorders such as lipid and iron dysregulation. Elevated iron load is commonly observed in the livers of patients with chronic hepatitis C, and hepatic iron overload is a highly profibrogenic and carcinogenic factor that increases the risk of HCC. However, the underlying mechanisms of elevated iron accumulation in HCV-infected livers remain to be fully elucidated. Here, we observed iron accumulation in cells and liver tissues under HCV infection and in mice expressing viral proteins from recombinant adenoviruses. We established two molecular mechanisms that contribute to increased iron load in cells caused by HCV infection. One is the transcriptional induction of hepcidin, the key hormone for modulating iron homeostasis. The transcription factor cAMP-responsive element-binding protein hepatocyte specific (CREBH), which was activated by HCV infection, not only directly recognizes the hepcidin promoter but also induces bone morphogenetic protein 6 (BMP6) expression, resulting in an activated BMP-SMAD pathway that enhances hepcidin promoter activity. The other is post-translational regulation of the iron-exporting membrane protein ferroportin 1 (FPN1), which is cleaved between residues Cys284 and Ala285 in the intracytoplasmic loop region of the central portion mediated by HCV NS3-4A serine protease. We propose that host transcriptional activation triggered by endoplasmic reticulum stress and FPN1 cleavage by viral protease work in concert to impair iron efflux, leading to iron accumulation in HCV-infected cells.

The effectiveness of dance movement therapy for individuals with Down syndrome: a pilot randomised controlled trial

BACKGROUND

Individuals with Down syndrome (DS) exhibit deficits in static and dynamic balance abilities and maladaptive functions. This study aimed to determine the effectiveness of dance movement therapy (DMT) group intervention in individuals with DS.

METHODS

The 31 participating individuals with DS, aged 5-29 years, were randomly divided into intervention (n = 16) and control (n = 15) groups. Posturography was used for static balance measurement, timed up and go test for dynamic balance measurement and the Achenbach System of Empirically Based Assessment (ASEBA) questionnaire for adaptive function and behavioural problem measurement in participants before and after the DMT interventions. The intervention group underwent 60-min DMT intervention once a week for 10 times, while the control group had usual daily activities.

RESULTS

The results revealed a statistically significant difference and large effect sizes in dynamic balance [(f(1, 29) = 4.52, P = 0.04, η_p   ² = 0.14)] in the intervention group compared with the control group. There were no statistically significant differences in static balance and ASEBA scores between the groups.

CONCLUSIONS

This study found that the DMT interventions helped to improve the dynamic balance in individuals with DS.

A girl with membranous nephropathy associated with ventriculoperitoneal shunt infection

Glomerulopathy associated with shunt infection is commonly membranoproliferative glomerulonephritis, whereas the causative organisms of secondary membranous nephropathy are usually viruses. We report a case of membranous nephropathy associated with shunt infection. The patient was born at 29-week gestation with a birth weight of 1178 g. Ventriculoperitoneal shunt surgery had been performed for congenital hydrocephalus. Thereafter, she had experienced seven shunt infections. At the age 13 years, proteinuria was detected in a school urinary screening. Urinalysis at our hospital demonstrated 3 + protein and 3 + blood. Laboratory testing demonstrated a serum creatinine 0.5 m/dl, albumin 2.5 g/dl, C-reactive protein (CRP) 13.7 mg/dl, and C3 182 mg/dl. Prior to repeat urinalysis, the patient developed vomiting and was admitted with suspected shunt infection. On admission, her body temperature was 36.0 ºC. Physical examination was unremarkable other than small stature and a palpable mass in the left upper quadrant. Urinalysis demonstrated 2 + protein and 1 + blood with no cells or casts. The urinary protein excretion was 3 g/day. Abnormal laboratory tests included erythrocyte sedimentation rate 102 mm/hr, CRP 11.67 mg/dl, IgG 2442 mg/dl, C3 177 mg/dl, and C4 44 mg/dl. Antibiotic therapy was initiated for a presumptive diagnosis of shunt infection and the shunt catheter was removed. Cultures obtained after antibiotic administration were negative. Proteinuria persisted after control of the shunt infection. Histology of a renal biopsy demonstrated membranous nephropathy with diffuse granular IgG staining and subepithelial deposits. Three possible pathomechanisms for her membranous nephropathy were considered.

Effectiveness of patient and staff cohorting to reduce the risk of vancomycin-resistant enterococcus (VRE) acquisition: a retrospective cohort study during a VRE outbreak in Japan

BACKGROUND

Patient and staff cohorting is part of a bundle approach in the response to multi-drug-resistant organisms, but its effectiveness is not fully clarified. This study compared the risks of acquiring vancomycin-resistant Enterococcus faecium (VREfm) at a hospital during a VREfm outbreak based on contact characteristics in order to better understand the effectiveness of cohorting.

METHODS

Exposure came from contact with patients with VREfm (infectors), including existing patients with VREfm and patients who acquired VREfm during the study period. Contact was defined as length of contact time, degree of sharing space, and care by the same nurses as those caring for infectors between January and March 2018. The outcome was VREfm acquisition as determined through monthly stool or rectal screening cultures. Incidence rates were calculated based on contact patterns, and incidence rate ratios (IRRs) were compared.

FINDINGS

Among 272 inpatients (4038 patient-days), 43 patients acquired VREfm with the same or similar pulsotype. Incidence rates were 8.45 per 1000 patient-days when susceptible inpatients were on the same ward as an infector but cared for by different nurses (reference), 16.96 when susceptible inpatients were on the same ward as an infector and cared for by the same nurses [IRR 2.01, 95% confidence interval (CI) 0.62-10.28], and 52.91 when susceptible inpatients shared a room with an infector (IRR 6.26, 95% CI 1.61-35.40).

CONCLUSION

Compared with susceptible inpatients in a different room from infectors and not being cared for by the same nurses, the risk of VREfm acquisition could be six times higher for susceptible inpatients who are in the same room as infectors, and could be double for susceptible inpatients cared for by the same nurses as infectors.

Joint instability causes catabolic enzyme production in chondrocytes prior to synovial cells in novel non-invasive ACL ruptured mouse model

OBJECTIVE

The Anterior Cruciate Ligament (ACL)-deficient model helps to clarify the mechanism of knee osteoarthritis (OA); however, the conventional ACL injury model could have included concurrent onset factors such as direct compression stress to cartilage and subchondral bone. In this study, we established a novel Non-invasive ACL-Ruptured mouse model without concurrent injuries and elucidated the relationship between OA progression and joint instability.

DESIGN

We induced the ACL-Rupture non-invasively in twelve-week-old C57BL/6 male mice and evaluated histological, macroscopical, and morphological analysis at 0 days. Next, we created the ACL-R, controlled abnormal tibial translation (CATT), and Sham groups. Then, the joint stability and OA pathophysiology were analyzed at 2, 4, and 8 weeks.

RESULTS

No intra-articular injuries, except for ACL rupture, were observed in the ACL-R model. ACL-R mice increased anterior tibial displacement compared to the Sham group (P < 0.001, 95% CI [-1.509 to -0.966]) and CATT group (P < 0.001, 95% CI [-0.841 to -0.298]) at 8 weeks. All mice in the ACL-R group caused cartilage degeneration. The degree of cartilage degeneration in the ACL-R group was higher than in the CATT group (P = 0.006) at 8 weeks. The MMP-3-positive cell rate of chondrocytes increased in the ACL-R group than CATT group from 4 weeks (P = 0.043; 95% CI [-28.32 to -0.364]) while that of synovial cells increased at 8 weeks (P = 0.031; 95% CI [-23.398 to -1.021]).

CONCLUSION

We successfully established a Non-invasive ACL-R model without intra-articular damage. Our model revealed that chondrocytes might react to abnormal mechanical stress prior to synovial cells while the knee OA onset.

Reducing the number of accepted species in Aspergillus series Nigri

The Aspergillus series Nigri contains biotechnologically and medically important species. They can produce hazardous mycotoxins, which is relevant due to the frequent occurrence of these species on foodstuffs and in the indoor environment. The taxonomy of the series has undergone numerous rearrangements, and currently, there are 14 species accepted in the series, most of which are considered cryptic. Species-level identifications are, however, problematic or impossible for many isolates even when using DNA sequencing or MALDI-TOF mass spectrometry, indicating a possible problem in the definition of species limits or the presence of undescribed species diversity. To re-examine the species boundaries, we collected DNA sequences from three phylogenetic markers (benA, CaM and RPB2) for 276 strains from series Nigri and generated 18 new whole-genome sequences. With the three-gene dataset, we employed phylogenetic methods based on the multispecies coalescence model, including four single-locus methods (GMYC, bGMYC, PTP and bPTP) and one multilocus method (STACEY). From a total of 15 methods and their various settings, 11 supported the recognition of only three species corresponding to the three main phylogenetic lineages: A. niger, A. tubingensis and A. brasiliensis. Similarly, recognition of these three species was supported by the GCPSR approach (Genealogical Concordance Phylogenetic Species Recognition) and analysis in DELINEATE software. We also showed that the phylogeny based on benA, CaM and RPB2 is suboptimal and displays significant differences from a phylogeny constructed using 5 752 single-copy orthologous proteins; therefore, the results of the delimitation methods may be subject to a higher than usual level of uncertainty. To overcome this, we randomly selected 200 genes from these genomes and performed ten independent STACEY analyses, each with 20 genes. All analyses supported the recognition of only one species in the A. niger and A. brasiliensis lineages, while one to four species were inconsistently delimited in the A. tubingensis lineage. After considering all of these results and their practical implications, we propose that the revised series Nigri includes six species: A. brasiliensis, A. eucalypticola, A. luchuensis (syn. A. piperis), A. niger (syn. A. vinaceus and A. welwitschiae), A. tubingensis (syn. A. chiangmaiensis, A. costaricensis, A. neoniger and A. pseudopiperis) and A. vadensis. We also showed that the intraspecific genetic variability in the redefined A. niger and A. tubingensis does not deviate from that commonly found in other aspergilli. We supplemented the study with a list of accepted species, synonyms and unresolved names, some of which may threaten the stability of the current taxonomy. Citation: Bian C, Kusuya Y, Sklenář F, D'hooge E, Yaguchi T, Ban S, Visagie CM, Houbraken J, Takahashi H, Hubka V (2022). Reducing the number of accepted species in Aspergillus series Nigri. Studies in Mycology 102: 95-132. doi: 10.3114/sim.2022.102.03.

Fast screening framework for infection control scenario identification

Due to the emergence of the novel coronavirus disease, many recent studies have investigated prediction methods for infectious disease transmission. This paper proposes a framework to quickly screen infection control scenarios and identify the most effective scheme for reducing the number of infected individuals. Analytical methods, as typified by the SIR model, can conduct trial-and-error verification with low computational costs; however, they must be reformulated to introduce additional constraints, and thus are inappropriate for case studies considering detailed constraint parameters. In contrast, multi-agent system (MAS) simulators introduce detailed parameters but incur high computation costs per simulation, making them unsuitable for extracting effective measures. Therefore, we propose a framework that implements an MAS for constructing a training dataset, and then trains a support vector regression (SVR) model to obtain effective measure results. The proposed framework overcomes the weaknesses of conventional methods to produce effective control measure recommendations. The constructed SVR model was experimentally verified by comparing its performance on datasets with expected and unexpected outputs. Although datasets producing an unexpected output decreased the prediction accuracy, by removing randomness from the training dataset, the accuracy of the proposed method was still high in these cases. High-precision predictions of the MAS-based simulation output were obtained for both test datasets in under one second of the computational time. Furthermore, the experimental results establish that the proposed framework can obtain intuitively correct outputs for unknown inputs, and produces sufficiently high-precision prediction with lower computation costs than an existing method.

OTUD1 deubiquitinase regulates NF-κB- and KEAP1-mediated inflammatory responses and reactive oxygen species-associated cell death pathways

Deubiquitinating enzymes (DUBs) regulate numerous cellular functions by removing ubiquitin modifications. We examined the effects of 88 human DUBs on linear ubiquitin chain assembly complex (LUBAC)-induced NF-κB activation, and identified OTUD1 as a potent suppressor. OTUD1 regulates the canonical NF-κB pathway by hydrolyzing K63-linked ubiquitin chains from NF-κB signaling factors, including LUBAC. OTUD1 negatively regulates the canonical NF-κB activation, apoptosis, and necroptosis, whereas OTUD1 upregulates the interferon (IFN) antiviral pathway. Mass spectrometric analysis showed that OTUD1 binds KEAP1, and the N-terminal intrinsically disordered region of OTUD1, which contains an ETGE motif, is indispensable for the KEAP1-binding. Indeed, OTUD1 is involved in the KEAP1-mediated antioxidant response and reactive oxygen species (ROS)-induced cell death, oxeiptosis. In Otud1^-/--mice, inflammation, oxidative damage, and cell death were enhanced in inflammatory bowel disease, acute hepatitis, and sepsis models. Thus, OTUD1 is a crucial regulator for the inflammatory, innate immune, and oxidative stress responses and ROS-associated cell death pathways.

OP0112 THE EVER-LARGEST ASIAN GWAS FOR SYSTEMIC SCLEROSIS AND TRANS-POPULATION META-ANALYSIS IDENTIFIED SEVEN NOVEL LOCI AND A CANDIDATE CAUSAL SNP IN A CIS-REGULATORY ELEMENT OF THE FCGR REGION

Background

Genome-wide association studies (GWASs) have identified 29 disease-associated single nucleotide polymorphisms (SNPs) for systemic sclerosis (SSc) in non-human leukocyte antigen (HLA) regions (1-7). While these GWASs have clarified genetic architectures of SSc, study subjects were mainly Caucasians limiting application of the findings to Asians.

Objectives

The study was conducted to identify novel causal variants for SSc specific to Japanese subjects as well as those shared with European population. We also aimed to clarify mechanistic effects of the variants on pathogenesis of SSc.

Methods

A total of 114,108 subjects comprising 1,499 cases and 112,609 controls were enrolled in the two-staged study leading to the ever-largest Asian GWAS for SSc. After applying a strict quality control both for genotype and samples, imputation was conducted using the reference panel of the phase 3v5 1,000 genome project data combined with a high-depth whole-genome sequence data of 3,256 Japanese subjects. We conducted logistic regression analyses and also combined the Japanese GWAS results with those of Europeans (6) by an inverse-variance fixed-effect model. Polygenicity and enrichment of functional annotations were evaluated by linkage disequilibrium score regression (LDSC), Haploreg and IMPACT programs. We also constructed polygenic risk score (PRS) to predict SSc development.

Results

We identified three (FCRLA-FCGR, TNFAIP3, PLD4) and four (EOMES, ESR1, SLC12A5, TPI1P2) novel loci in Japanese GWAS and a trans-population meta-analysis, respectively. One of Japanese novel risk SNPs, rs6697139, located within FCGR gene clusters had a strong effect size (OR 2.05, P=4.9×10-11). We also found the complete LD variant, rs10917688, was positioned in cis-regulatory element and binding motif for an immunomodulatory transcription factor IRF8 in B cells, another genome-wide significant locus in our trans-ethnic meta-analysis and the previous European GWAS. Notably, the association of risk allele of rs10917688 was significant only in the presence of the risk allele of the IRF8. Intriguingly, rs10917688 was annotated as one enhancer-related histone marks, H3K4me1, in B cells, implying that FCGR gene(s) in B cells may play an important role in the pathogenesis of SSc. Furhtermore, significant heritability enrichment of active histone marks and a transcription factor C-Myc were found in B cells both in European and Japanese populations by LDSC and IMPACT, highlighting a possibility of a shared disease mechanism where abnormal B-cell activation may be one of the key drivers for the disease development. Finally, PRS using effects sizes of European GWAS moderately fit in the development of Japanese SSc (AUC 0.593), paving a path to personalized medicine for SSc.

Conclusion

Our study identified seven novel susceptibility loci in SSc. Downstream analyses highlighted a novel disease mechanism of SSc where an interactive role of FCGR gene(s) and IRF8 may accelerate the disease development and B cells may play a key role on the pathogenesis of SSc.

References

[1]F. C. Arnett et al. Ann Rheum Dis, 2010.

[2]T. R. Radstake et al. Nat Genet, 2010.

[3]Y. Allanore et al. PLoS Genet, 2011.

[4]O. Gorlova et al. PLoS Genet, 2011.

[5]C. Terao et al. Ann Rheum Dis, 2017.

[6]E. López-Isac et al. Nat Commun, 2019.

[7]W. Pu et al. J Invest Dermatol, 2021.

Disclosure of Interests

None declared

Gray matter volume and burnout severity among medical professionals

Introduction

Occupational burnout has become a pervasive problem in human services. Medical professionals are particularly vulnerable to burnout, which may lead to reduced motivation, medical errors, and voluntary absenteeism. To ensure effect functioning of medical systems, better understanding of burnout among medical professionals is warranted.

Objectives

We aimed to investigate the structural brain correlates of burnout severity among medical professionals.

Methods

Nurses in active service underwent structural magnetic resonance imaging. We assessed their burnout severity using self-reported psychological questionnaires. This study was approved by the Committee on Medical Ethics of Kyoto University and was conducted in accordance with the Code of Ethics of the World Medical Association.

Results

The results reflected considerable individual differences in burnout severity in our sample. Our findngs revealed that the levels of burnout severity were associated with the regional gray matter volumes in brain areas such as ventromedial prefrontal cortex and insula.

Conclusions

Since the outbreak of the COVID-19 pandemic, medical professionals have faced even greater stress. We hope that our findings will contribute to a better understanding of the mechanisms of burnout and offer useful insights for developing effective interventions to manage stress and burnout.

Disclosure

No significant relationships.

Polymorphism and optical, magnetic and thermal properties of the either phyllo- or inosilicate-analogous borosulfate Cu[B2(SO4)4]

Two polymorphs of the borosulfate Cu[B₂(SO₄)₄] can be selectively prepared by solvothermal syntheses. The crystal structures of inosilicate-analogous α-Cu[B₂(SO₄)₄] (P1̄, no. 2, a = 5.2636(2), b = 7.1449(2), c = 7.9352(2) Å, α = 73.698(2)°, β = 70.737(2)°, γ = 86.677(2)°, 65 parameters, R_Bragg = 0.0052) and the new phyllosilicate-analogous polymorph β-Cu[B₂(SO₄)₄] (P2₁/n, no. 14, a = 7.712(3), b = 8.149(3), c = 9.092(3) Å, β = 111.22(1)°, 3829 independent reflections, 106 parameters, wR₂ = 0.054) are discussed. Further, the optical, magnetic and thermal properties of both polymorphs are investigated with focus on the role of the Cu²⁺ cation and its Jahn-Teller effect. The findings are confirmed by DFT calculations yielding insights in the stability of the synthesised polymorphs as well as a predicted γ-modification. Additionally, the crystal structures of two polymorphs of copper hydrogensulfate Cu(HSO₄)₂-I (P2₁/n, no. 14, a = 4.7530(2), b = 8.5325(4), c = 7.3719(3) Å, β = 100.063(1)°, 1063 independent reflections, 55 parameters, wR₂ = 0.052) and Cu(HSO₄)₂-II (P1̄, no. 2, a = 4.79.88(8), b = 7.857(1), c = 8.057(1) Å, α = 77.86(1)°, β = 87.02(1)°, γ = 89.82(1)°, 1044 independent reflections, 109 parameters, wR₂ = 0.132) as well as that of Cu[S₂O₇] (C2/c, no. 15, a = 6.6341(4), b = 8.7302(5), c = 9.0555(8) Å, β = 104.763(3)°, 1117 independent reflections, 48 parameters, wR₂ = 0.049) are presented and the cyclosilicate-analogous borosulfate Cu[B(SO₄)₂(HSO₄)] is fully characterised with respect to its optical and thermal properties.

Precise Measurement of Differential Cross Sections of the Σ^{-}p→Λn Reaction in Momentum Range 470-650 MeV/c

The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for the Σ^{-} momentum (p_{Σ}) ranging from 470 to 650  MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the Σ^{-}p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst)  mb for 470<p_{Σ}(MeV/c)<550 and 550<p_{Σ}(MeV/c)<650, respectively. These results show a drastic improvement compared with past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.

Preparation status of missing-mass spectroscopy for 𝚵 hypernuclei with S-2S magnetic spectrometer

J-PARC E70 experiment measures the missing-mass of Ξ hypernuclei (12ΞBe) in Hadron Experimental Facility at J-PARC. We aim to reach the best missing-mass resolution of 2 MeV/c2 in FWHM with a new magnetic spectrometer S-2S. The high-resolution spectroscopy of Ξ hypernuclei will play an important role to understand the unknown ΞN interaction. The experiment will start at the beginning of 2023. This article presents the preparation status.

SIRVVD model-based verification of the effect of first and second doses of COVID-19/SARS-CoV-2 vaccination in Japan

As of August 2021, COVID-19 is still spreading in Japan. Vaccination, one of the key measures to bring COVID-19 under control, began in February 2021. Previous studies have reported that COVID-19 vaccination reduces the number of infections and mortality rates. However, simulations of spreading infection have suggested that vaccination in Japan is insufficient. Therefore, we developed a susceptible-infected-recovered-vaccination1-vaccination2-death model to verify the effect of the first and second vaccination doses on reducing the number of infected individuals in Japan; this includes an infection simulation. The results confirm that appropriate vaccination measures will sufficiently reduce the number of infected individuals and reduce the mortality rate.

Recent progress and future prospects of hyperon nucleon scattering experiment

A new hyperon-proton scattering experiment, dubbed J-PARC E40, was performed to measure differential cross sections of the Σ+p, Σ−p elastic scatterings and the Σ−p → Λn scattering by identifying a lot of Σ particles in the momentum ranging from 0.4 to 0.8 GeV/c produced by the π±p → K+Σ± reactions. We successfully measured the differential cross sections of these three channels with a drastically improved accuracy with a fine angular step. These new data will become important experimental constraints to improve the theories of the two-body baryon-baryon interactions. Following this success, we proposed a new experiment to measure the differential cross sections and spin observables by using a highly polarized Λ beam for providing quantitative information on the ΛN interaction. The results of three Σp channels and future prospects of the Λp scattering experiment are described.

Protein-protein interactions between jasmonate-related master regulator MYC and transcriptional mediator MED25 depend on a short binding domain

A network of protein–protein interactions (PPI) is involved in the activation of (+)-7-iso-jasmonoyl-L-isoleucine (JA-Ile), a plant hormone that regulates plant defense responses as well as plant growth and development. In the absence of JA-Ile, inhibitory protein jasmonate-ZIM-domain (JAZ) represses JA-related transcription factors, including a master regulator, MYC. In contrast, when JA-Ile accumulates in response to environmental stresses, PPI occurs between JAZ and the F-box protein COI1, which triggers JAZ degradation, resulting in derepressed MYC that can interact with the transcriptional mediator MED25 and upregulate JA-Ile-related gene expression. Activated JA signaling is eventually suppressed through the catabolism of JA-Ile and feedback suppression by JAZ splice variants containing a cryptic MYC-interacting domain (CMID). However, the detailed structural basis of some PPIs involved in JA-Ile signaling remains unclear. Herein, we analyzed PPI between MYC3 and MED25, focusing on the key interactions that activate the JA-Ile signaling pathway. Biochemical assays revealed that a short binding domain of MED25 (CMIDM) is responsible for the interaction with MYC, and that a bipartite interaction is critical for the formation of a stable complex. We also show the mode of interaction between MED25 and MYC is closely related to that of CMID and MYC. In addition, quantitative analyses on the binding of MYC3-JAZs and MYC3-MED25 revealed the order of binding affinity as JAZ^Jas < MED25^CMIDM < JAZ^CMID, suggesting a mechanism for how the transcriptional machinery causes activation and negative feedback regulation during jasmonate signaling. These results further illuminate the transcriptional machinery responsible for JA-Ile signaling.

Nonmagnetic J=0 State and Spin-Orbit Excitations in K_{2}RuCl_{6}

Spin-orbit Mott insulators composed of t_{2g}^{4} transition metal ions may host excitonic magnetism due to the condensation of spin-orbital J=1 triplons. Prior experiments suggest that the 4d antiferromagnet Ca_{2}RuO_{4} embodies this notion, but a J=0 nonmagnetic state as a basis of the excitonic picture remains to be confirmed. We use Ru L_{3}-edge resonant inelastic x-ray scattering to reveal archetypal J multiplets with a J=0 ground state in the cubic compound K_{2}RuCl_{6}, which are well described within the LS-coupling scheme. This result highlights the critical role of unquenched orbital moments in 4d-electron compounds and calls for investigations of quantum criticality and excitonic magnetism on various crystal lattices.

Impact of Magnetic Field Configuration on Heat Transport in Stellarators and Heliotrons

We assess the magnetic field configuration in modern fusion devices by comparing experiments with the same heating power, between a stellarator and a heliotron. The key role of turbulence is evident in the optimized stellarator, while neoclassical processes largely determine the transport in the heliotron device. Gyrokinetic simulations elucidate the underlying mechanisms promoting stronger ion scale turbulence in the stellarator. Similar plasma performances in these experiments suggests that neoclassical and turbulent transport should both be optimized in next step reactor designs.

Effectiveness of the COVID-19 Contact-Confirming Application (COCOA) Based on Multi-Agent Simulation

As of Aug. 2020, coronavirus disease 2019 (COVID-19) is still spreading in the world. In Japan, the Ministry of Health, Labour and Welfare developed “COVID-19 Contact-Confirming Application (COCOA),” which was released on June 19, 2020. By utilizing COCOA, users can know whether or not they had contact with infected persons. If those who had contact with infected individuals keep staying at home, they may not infect those outside. However, effectiveness decreasing the number of infected individuals depending on the app’s various usage parameters is not clear. If it is clear, we could set the objective value of the app’s usage parameters (e.g., the usage rate of the total populations) and call for installation of the app. Therefore, we develop a multi-agent simulator that can express COVID-19 spreading and usage of the apps, such as COCOA. In this study, we describe the simulator and the effectiveness of the app in various scenarios. The result obtained in this study supports those of previously conducted studies.

Analysis of clinical characteristics, prognosis and antibody pathogenicity of pemphigus patients positive for anti-desmoglein IgG autoantibodies in remission: a retrospective cohort study

BACKGROUND

The detection of serum anti-desmoglein (Dsg) IgG autoantibodies has been reported to be useful for assessment of disease activity in pemphigus. However, previous studies have reported that anti-Dsg autoantibodies remain detectable in some patients without active pemphigus lesions.

OBJECTIVES

To investigate the clinical characteristics and antibody pathogenicity of pemphigus patients positive for anti-Dsg IgG autoantibodies in remission.

METHODS

We retrospectively investigated pemphigus patients with a history of clinical remission who visited the Department of Dermatology of Keio University during 2019 and 2020. The antibody pathogenicity was assessed by bead aggregation assay.

RESULTS

When patients were recognized as having entered remission (PDAI = 0 and PSL ≦ 10 mg/day for 2 months), serum autoantibodies against Dsg were detected in 72 of 132 patients (54.5%, positive group; PG), but were not detected in 60 patients (45.5%, negative group; NG). Anti-Dsg antibody titres in remission declined from the active phase in 33 patients in the PG for whom data were available. There were no differences in the chance of reducing PSL to 5 mg/day (P = 0.885) and rate of relapse (P = 0.279) between PG and NG, but fewer patients in PG discontinued corticosteroids (P = 0.004). The ability of patients' sera to block aggregation of Dsg/desmocollin beads was significantly reduced in remission compared to the active phase. However, our results revealed that whole sera in remission still had pathogenic activity in seven of nine patients, and the approximately equal amounts of anti-Dsg antibodies in active phase and remission showed similar pathogenicity.

CONCLUSIONS

This study will provide guidance in cases where autoantibodies are found to be positive in pemphigus patients during remission or steroid reduction.

Impact of State of Emergency Declaration for COVID-19 on Cancer Screening Behavior in Japan

 

Status of cancer screening behavior is changing due to the effects of the state of emergency for Covid-19 in Japan. Based on data from three medical institutions that provide cancer screening throughout Japan, we compared the number of examinees undergoing cancer screening by month in 2019 and 2020. From April to May 2020, the number of examinees decreased by about 50-80% compared to the previous year, but after June, recovered to the same level as previous year. In addition, the number of examinees undergoing resident cancer screening tended to decrease more than that of occupational screening. The causes of the decrease are 1. examinee was wary of the risk of infection at the examination site. 2. medical institution postponed cancer screening because the Ministry of Health, Labor and Welfare issued a notice to refrain from endoscopy, which is less urgent. 3. It was considered that the municipalities that carried out the examinations were wary of the spread of the infection and postponed or canceled the recommendation of the cancer screening.

Key messages

Declaration of emergency has reduced the number of cancer screening examinees. Impact on cancer mortality will be an issue for the future.

Effect of endothelial nitric oxide synthase gene polymorphism on cardiovascular death and nonfatal myocardial infarction in Japanese general population

Introduction

Single nucleotide polymorphisms (SNP) of endothelial nitric oxide synthase (NOS3) have been reported to be associated with diabetes mellitus and myocardial infarction. However, few reports have prospectively investigated the effects of NOS3 SNP on cardiovascular death and nonfatal myocardial infarction.

Purpose

The purpose of this study was to investigate the impact of NOS3 SNP on cardiovascular death and the development of nonfatal myocardial infarction.

Methods

This prospective cohort study included 2,752 subjects (aged ≥40) who participated in a community based health checkup. We genotyped two SNPs within NOS3 (rs1808593, rs1799983). All subjects were prospectively followed during the median follow-up period of 15.4 years with the end point of cardiovascular death and nonfatal myocardial infarction.

Results

The homozygous G-allele (GG), heterozygous (GT), and homozygous T-allele (TT) carriers of rs1808593 were identified in 60 (2%), 706 (26%), and 1,986 (72%) subjects, respectively. Kaplan-Meier analysis demonstrated that homozygous G-allele carriers of rs1808593 had the greater risk than those without. Multivariate Cox proportional hazard regression analysis revealed that the homozygous G allele of rs1808593 was associated with cardiovascular death and the development of nonfatal myocardial infarction after adjusting for confounding risk factors.

Conclusions

NOS3 gene polymorphism could be a genetic risk factor for cardiovascular death and nonfatal myocardial infarction in the Japanese general population.

Funding Acknowledgement

Type of funding sources: None. Figure 1

URAT1-selective inhibition ameliorates insulin resistance by attenuating diet-induced hepatic steatosis and BAT whitening in mice

Background

Accumulating evidence suggests that high uric acid is strongly associated with obesity and metabolic syndrome and drives the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Although urate transporter-1 (URAT1), which is primarily expressed in the kidney, plays a critical role in the development of hyperuricemia, its pathophysiological implication in NAFLD and insulin resistance remains unclear.

Objectives

We hypothesizes that URAT1 plays an important role in obesity-induced metabolic disorders, and URAT1-selective inhibitor treatment ameliorates systemic insulin resistance, NAFLD and adipose tissue dysfunction using diet-induced obese mice.

Methods

Mice fed a high-fat diet (HFD) for 16 to 18 weeks or a normal-fat diet (NFD) were treated with or without a novel oral URAT1-selective inhibitor (dotinurad [50 mg/kg/day]) for another 4 weeks.

Results

Dotinurad administration significantly ameliorated HFD-induced obesity and insulin resistance. We found that URAT1 was also expressed in the liver and brown adipose tissue (BAT) other than kidney. HFD markedly induced NAFLD, which was characterized by severe hepatic steatosis, as well as the elevation of serum ALT activity and tissue inflammatory cytokine genes (Ccl2 and TNFα), all of which were attenuated by dotinurad. Likewise, HFD significantly increased URAT1 expression in BAT, resulting in the lipid accumulation (whitening of BAT) and increased production of tissue reactive oxygen species, which were reduced by dotinurad via UCP1 activation.

Conclusions

A novel URAT1-selective inhibitor, dotinurad, ameliorates insulin resistance by attenuating hepatic steatosis and promoting rebrowning of lipid-rich BAT in HFD-induced obese mice. URAT1 serves as a key regulator of the pathophysiology of metabolic syndrome, and may be a new therapeutic target for insulin-resistant individuals, particularly those with concomitant NAFLD.

Funding Acknowledgement

Type of funding sources: None.

Gender differences in the impact of plasma xanthine oxidoreductase activity on coronary artery spasm

Background

It has been reported that decreased nitric oxide bioavailability due to increased reactive oxygen species (ROS) is one of the most important causes of coronary artery spasm (CAS). Xanthine oxidoreductase (XOR) is the rate-limiting enzyme for uric acid (UA) production and plays a pivotal role in generating ROS. It was reported that the gender differences exist in the impact of serum UA levels on cardiovascular risks. We previously demonstrated that increased plasma XOR activity is significantly associated with the incidence of CAS. However, the gender differences in the impact of plasma XOR activity on CAS remain unclear.

Purpose

The aim of this study was to examine the gender differences in the clinical impact of plasma XOR activity on CAS.

Methods

We investigated plasma XOR activity in 132 patients suspected for CAS (male, n=78; female, n=54), and underwent intracoronary acetylcholine provocation test. XOR activity assay was performed using stable isotope-labeled substrate and liquid chromatography-triple quadrupole mass spectrometry. Provoked CAS was defined as total or subtotal occlusion (≥90%) with accompanying symptoms of chest pain and/or ischemic ST-segment changes on the electrocardiogram. We excluded the patients who had significant coronary artery stenosis (≥50%) and/or were taking XOR inhibitors.

Results

Plasma XOR activity was significantly lower in female compared with male patients (30.3 pmol/h/mL, interquartile range (IQR) 22.8–42.7 vs. 51.7 pmol/h/mL, IQR 34.7–101.8; P&lt;0.001). CAS was provoked in 36 male patients and 17 female patients, and they each had significantly higher plasma XOR activity compared with those without, respectively. Multivariate logistic regression analysis showed that plasma XOR activity was independently associated with the incidence of CAS in both genders after adjustment for confounding factors. The optimal cut-off values for predicting CAS were lower in female than those in male patients (52.3 vs. 91.6 pmol/h/mL). Multivariate analysis demonstrated that female patients with high XOR activity (≥52.3 pmol/h/mL; odds ratio [OR] 22.6, P&lt;0.001) exhibited a higher incidence of CAS compared with that in male patients (≥91.6 pmol/h/mL; OR 8.2, P&lt;0.001).

Conclusions

Plasma XOR activity was an independent predictor for the incidence of CAS in both genders. The impact of plasma XOR activity on CAS was stronger in female patients than in male patients.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

SIR model-based verification of effect of COVID-19 Contact-Confirming Application (COCOA) on reducing infectors in Japan

As of April 2021, the coronavirus disease (COVID-19) continues to spread in Japan. To overcome COVID-19, the Ministry of Health, Labor, and Welfare of the Japanese government developed and released the COVID-19 Contact-Confirming Application (COCOA) on June 19, 2020. COCOA users can know whether they have come into contact with infectors. If persons who receive a contact notification through COCOA undertake self-quarantine, the number of infectors in Japan will decrease. However, the effectiveness of COCOA in reducing the number of infectors depends on the usage rate of COCOA, the rate of fulfillment of contact condition, the rate of undergoing the reverse transcription polymerase chain reaction (RT-PCR) test, the false negative rate of the RT-PCR test, the rate of infection registration, and the self-quarantine rate. Therefore, we developed a Susceptible-Infected-Removed (SIR) model to estimate the effectiveness of COCOA. In this paper, we introduce the SIR model and report the simulation results for different scenarios that were assumed for Japan.

Proximate ferromagnetic state in the Kitaev model material α-RuCl3

α-RuCl₃ is a major candidate for the realization of the Kitaev quantum spin liquid, but its zigzag antiferromagnetic order at low temperatures indicates deviations from the Kitaev model. We have quantified the spin Hamiltonian of α-RuCl₃ by a resonant inelastic x-ray scattering study at the Ru L₃ absorption edge. In the paramagnetic state, the quasi-elastic intensity of magnetic excitations has a broad maximum around the zone center without any local maxima at the zigzag magnetic Bragg wavevectors. This finding implies that the zigzag order is fragile and readily destabilized by competing ferromagnetic correlations. The classical ground state of the experimentally determined Hamiltonian is actually ferromagnetic. The zigzag state is stabilized by quantum fluctuations, leaving ferromagnetism – along with the Kitaev spin liquid – as energetically proximate metastable states. The three closely competing states and their collective excitations hold the key to the theoretical understanding of the unusual properties of α-RuCl₃ in magnetic fields.

RuCl₃ has stood out as a prime candidate in the search for quantum spin liquids; however, its antiferromagnetic ordering at low temperature suggests deviations from typical QSL models. Here, using resonant inelastic x-ray scattering, the authors provide a comprehensive determination of the low energy effective Hamiltonian.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.