Genetic Risk, Lifestyle Adherence, and Risk of Developing Hyperuricaemia in a Japanese Population.

OBJECTIVE: To investigate the inter-relationships among genetic risk, healthy lifestyle adherence, and hyperuricaemia susceptibility. METHODS: This prospective cohort study was conducted with 7,241 hyperuricaemia-free individuals aged ≥ 20 years from the Tohoku Medical Megabank Community-based cohort study. A comprehensive lifestyle score included body mass index, smoking, drinking, and physical activity, and a polygenic risk score (PRS) was constructed based on uric acid loci from a previous genome-wide association study meta-analysis. A multiple logistic regression model was used to estimate the association between genetic risk, healthy lifestyle, and hyperuricaemia incidence and calculate the area under the receiver operating characteristic curve (AUROC). Hyperuricaemia was defined as a uric acid level ≥7.0 mg/dl or a self-reported history of hyperuricaemia. RESULTS: Of the 7,241 adults (80.7% females; mean [SD] age: 57.7 [12.6] years), 217 (3.0%) developed hyperuricaemia during 3.5 years of follow-up. Genetic risk correlated with hyperuricaemia development (P for interaction = 0.287), and lifestyle risks were independently associated. Those with a high genetic risk and poor lifestyle had the highest risk (odds ratio: 5.34; 95% confidence interval [CI]: 2.61-12.10). Although not statistically significant, incorporating the PRS in the model with lifestyle information improved predictive ability (AUROC = 0.771, 95% CI: 0.736-0.806 for lifestyle; AUROC = 0.785, 95% CI: 0.751-0.819 for lifestyle and PRS; p = 0.07). CONCLUSION: : A healthy lifestyle to prevent hyperuricaemia, irrespective of genetic risk, may mitigate the genetic risk. Genetic risk may complement lifestyle factors in identifying individuals at a heightened hyperuricaemia risk.

SHIN-2 exerts potent activity against VanA-type vancomycin-resistant Enterococcus faecium in vitro by stabilizing the active site loop of serine hydroxymethyltransferase.

Novel classes of antibiotics are needed to improve the resilience of the healthcare system to antimicrobial resistance (AMR), including vancomycin resistance. vanA gene cluster is a cause of vancomycin resistance. This gene cluster is transferred and spreads vancomycin resistance from Enterococcus spp. to Staphylococcus aureus. Therefore, novel antibacterial agents are required to combat AMR, including vanA-type vancomycin resistance. Serine hydroxymethyltransferase (SHMT) is a key target of antibacterial agents. However, the specific binding mechanisms of SHMT inhibitors remain unclear. Detailed structural information will contribute to understanding these mechanisms. In this study, we found that (+)-SHIN-2, the first in vivo active inhibitor of human SHMT, is strongly bound to the Enterococcus faecium SHMT (efmSHMT). Comparison of the crystal structures of apo- and (+)-SHIN-2-boud efmSHMT revealed that (+)-SHIN-2 stabilized the active site loop of efmSHMT via hydrogen bonds, which are critical for efmSHMT inhibition. Additionally, (+)-SHIN-2 formed hydrogen bonds with serine, forming the Schiff's base with pyridoxal 5'-phosphate, which is a co-factor of SHMT. Furthermore, (+)-SHIN-2 exerted biostatic effects on vancomycin-susceptible and vanA-type vancomycin-resistant E. faecium in vitro, indicating that SHMT inhibitors do not induce cross-resistance to vanA-type vancomycin. Overall, these findings can aid in the design of novel SHMT inhibitors to combat AMR, including vancomycin resistance.

2'-ß-Methylselenyl nucleos(t)ide analogs as reverse transcriptase inhibitors against diverse HIV mutants.

Nucleoside reverse transcriptase inhibitors (NRTIs) have been extensively studied as drugs targeting HIV RT. However, the practice or use of approved NRTIs lacking the 3'-hydroxy group often promotes frequent HIV mutations and generates drug-resistance. Here, we describe a novel NRTI with 2'-ß-methylselenyl modification. We found that this modification inhibited the DNA elongation reaction by HIV-1 RT despite having a 3'-hydroxy group. Moreover, the conformation of this nucleoside analog is controlled at C3'-endo, a conformation that resists excision from the elongating DNA by HIV RT. Accordingly, the designed analogs exhibited activity against both wild-type HIV and multidrug-resistant HIV mutants.

Combined Fat Mass and Fat-free Mass Indices and Lung Function Among Japanese Population: The Tohoku Medical Megabank Community-based Cohort Study.

BACKGROUND: Although fat mass index (FMI) and fat-free mass index (FFMI) affect lung function, FMI and FFMI are not independent of each other, since FMI and FFMI were calculated as fat mass and fat-free mass divided by height squared, respectively. We aimed to examine the association of combined FMI and FFMI with lung function. METHODS: In this cross-sectional study, lung function was evaluated using forced expiratory volume at 1 s (FEV1) and forced vital capacity (FVC) measured using spirometry. Both FMI and FFMI were classified into sex-specific quartiles (16 groups). Analysis of covariance was used to assess the associations of combined FMI and FFMI with lung function. The trend test was conducted by stratifying the FMI and FFMI, scoring the categories from 1-4 (lowest-highest), and entering the number as a continuous term in the regression model. RESULTS: This study included 3,736 men and 8,821 women aged ≥20 years living in Miyagi Prefecture, Japan. The mean FEV1 was 3.0 (standard deviation [SD], 0.7) L for men and 2.3 (SD, 0.5) L for women. The mean FVC was 3.8 (SD, 0.7) L for men and 2.8 (SD, 0.5) L for women. FMI was inversely associated with lung function among all FFMI subgroups in both sexes. Conversely, FFMI was positively associated with lung function in all FMI subgroups in both sexes. CONCLUSION: Higher FMI was associated with lower lung function independent of FFMI; higher FFMI was associated with higher lung function independent of FMI. Reducing FMI and maintaining FFMI might be important for respiratory health.

Association of physiological factors with grip and leg extension strength: tohoku medical megabank community-based cohort study.

BACKGROUND: Upper and lower extremity muscle strength can be used to predict health outcomes. However, the difference between the relation of upper extremity muscle and of lower extremity muscle with physiological factors is unclear. This study aimed to evaluate the association between physiological data and muscle strength, measured using grip and leg extension strength, among Japanese adults. METHODS: We conducted a cross-sectional study of 2,861 men and 6,717 women aged ≥ 20 years living in Miyagi Prefecture, Japan. Grip strength was measured using a dynamometer. Leg extension strength was measured using a hydraulic isokinetic leg press machine. Anthropometry and physiological data, including blood pressure, calcaneal ultrasound bone status, pulmonary function, carotid echography, and blood information, were assessed. We used a general linear model adjusted for age, body composition, and smoking status to evaluate the association between muscle strength and physiological factors. RESULTS: Grip and leg extension strength were positively associated with bone area ratio, vital capacity, forced vital capacity, forced expiratory volume in one second, and estimated glomerular filtration rate, and negatively associated with waist circumference and percentage body fat mass in both the sexes. Diastolic blood pressure was positively associated with grip strength in both the sexes and leg extension strength in men, but not women. High-density lipoprotein cholesterol and red blood cell counts were positively associated with grip and leg extension strength in women, but not men. In both the sexes, pulse rate, total cholesterol, and uric acid were consistently associated with only leg extension strength, but not grip strength. In women, glycated hemoglobin demonstrated negative and positive associations with grip and leg extension strength, respectively. CONCLUSIONS: Grip and leg extension strength demonstrated similar associations with anthropometry, pulmonary function, and estimated glomerular filtration rate, but the associations with the other factors were not always consistent.

Synthesis and Cytotoxicity of Cyclic Octapeptide Surugamides with Varied N-Acyl Moieties.

Surugamides are a group of non-ribosomal peptides produced by Streptomyces spp. Several derivatives possess acyl groups, which are proposed to be attached to a lysine side chain after backbone-macrocyclization during biosynthesis. To date, five different acyl groups have been identified in nature, yet their impacts on biological activity remain underexplored. Here we synthesized surugamide B derivatives with varied acyl moieties. Biological evaluations revealed that larger hydrophobic acyl groups on lysine ε-NH2 enhance cytotoxicity.

Antiviral Activity and Resistance Profile of the Novel HIV-1 Non-Catalytic Site Integrase Inhibitor JTP-0157602.

HIV-1 integrase (IN) is an essential enzyme for viral replication. Non-catalytic site integrase inhibitors (NCINIs) are allosteric HIV-1 IN inhibitors and a potential new class of antiretrovirals. In this report, we identified a novel NCINI, JTP-0157602, with an original scaffold. JTP-0157602 exhibited potent antiviral activity against HIV-1 and showed a serum-shifted 90% effective concentration (EC90) of 138 nM, which is comparable to those of the FDA-approved IN strand transfer inhibitors (INSTIs). This compound was fully potent against a wide range of recombinant viruses with IN polymorphisms, including amino acids 124/125, a hot spot of IN polymorphisms. In addition, JTP-0157602 retained potent antiviral activity against a broad panel of recombinant viruses with INSTI-related resistance mutations, including multiple substitutions that emerged in clinical studies of INSTIs. Resistance selection experiments of JTP-0157602 led to the emergence of A128T and T174I mutations, which are located at the lens epithelium-derived growth factor/p75 binding pocket of IN. JTP-0157602 inhibited HIV-1 replication mainly during the late phase of the replication cycle, and HIV-1 virions produced by reactivation from HIV-1 latently infected Jurkat cells in the presence of JTP-0157602 were noninfectious. These results suggest that JTP-0157602 and analog compounds can be used to treat HIV-1 infectious diseases. IMPORTANCE Non-catalytic site integrase inhibitors (NCINIs) are allosteric HIV-1 integrase (IN) inhibitors that bind to the lens epithelium-derived growth factor (LEDGF)/p75 binding pocket of IN. NCINIs are expected to be a new class of anti-HIV-1 agents. In this study, we present a novel NCINI, JTP-0157602, which has potent activity against a broad range of HIV-1 strains with IN polymorphisms. Furthermore, JTP-0157602 shows strong antiviral activity against IN strand transfer inhibitor-resistant mutations, suggesting that JTP-0157602 and its analogs are potential agents for treating HIV-1 infections. Structural modeling indicated that JTP-0157602 binds to the LEDGF/p75 binding pocket of IN, and the results of in vitro resistance induction revealed the JTP-0157602 resistance mechanism of HIV-1. These data shed light on developing novel NCINIs that exhibit potent activity against HIV-1 with broad IN polymorphisms and multidrug-resistant HIV-1 variants.

Mental Health Problems among University Students under the Prolonged COVID-19 Pandemic in Japan: A Repeated Cross-Sectional Survey.

Numerous studies have investigated the impact of the coronavirus disease 2019 (COVID-19) pandemic on mental health among university students within a year of its onset, but few have examined the impact of a prolonged pandemic on university life. This study aimed to evaluate the impact of the COVID-19 pandemic on the mental health of students in a large university community. Online questionnaire surveys were conducted on students from March 24 to April 14 (first survey, n = 3,357) and December 2-23, 2021 (second survey, n = 2,604). The questionnaires included items on demographic data, living conditions, and mental health status as measured using the Patient Health Questionnaire-9 for depressive symptoms and the Generalized Anxiety Disorder-7 scale for anxiety symptoms. The results showed that, compared with undergraduate students, graduate students, except those in Medicine, Dentistry, and Pharmaceutical Science courses, had more anxiety symptoms. Furthermore, among undergraduate students, depressive and anxiety symptoms were significantly higher in fourth- than in first-year students. Logistic regression analyses of data from both surveys revealed the seven risk factors associated with depressive or anxiety symptoms that affected the mental health of university students throughout the COVID-19 pandemic: 1) female or nonbinary gender, 2) graduate student, 3) quarantine experience due to COVID-19, 4) isolation from friends and acquaintances, 5) disorganized pattern of daily life, 6) worse financial situation, and 7) no availability of consultations regarding health, life, and finances. These findings suggest that mental health measures for university students need to be designed specific to each course.

Design and Progress of Child Health Assessments at Community Support Centers in the Birth and Three-Generation Cohort Study of the Tohoku Medical Megabank Project.

The Tohoku Medical Megabank Project (TMM) has been conducting a birth and three-generation cohort study (the BirThree Cohort Study). We recruited 73,529 pregnant women and their family members for this cohort study, which included 23,143 newborns and 9,459 of their siblings. We designed and are in the process of conducting three-step health assessments for each newborn at approximately ages of 5, 10 and 16. These health assessments are administered at seven community support centers. Trained genome medical research coordinators conduct physical examinations of and collect biological specimens from each participant. The Sendai Children's Health Square has been established as the headquarters for these child health assessments and is utilized to accumulate knowledge that can facilitate the proper practice of child health assessments. We designed all the relevant health assessments facilities to allow parents and their children to participate in the health assessments concomitantly. Our centers serve as places where child participants and their parents can feel at ease as a result of the implementation of safety measures and child hospitality measures. The TMM BirThree Cohort Study is in the process of conducting strategically detailed health assessments and genome analysis, which can facilitate studies concerning the gene-environment interactions relevant to noncommunicable diseases. Through these operations, our study allows for a significant depth of data to be collected in terms of the number of biospecimens under study and the comprehensiveness of both basic and clinical data alongside relevant family information.

Impact of the COVID-19 pandemic on racial and ethnic minorities in Japan.

This study compared clinico-epidemiological characteristics between Japanese and non-Japanese coronavirus disease 2019 (COVID-19) patients under the pandemic in Japan. We retrospectively analysed nationwide data of hospitalised COVID-19 patients before 31 March 2021. Epidemic curves were constructed to identify the case distribution over time. A total of 28 093 patients were Japanese and 1335 patients were non-Japanese. The major racial and ethnic minorities were East Asians (n = 521), South Asians (n = 260) and Latin Americans (n = 270). Non-Japanese patients were younger and more likely to travel to COVID-19 endemic countries (7.7%), had meals with other people (17.8%), stayed in crowded places (17.9%) and worked mainly in restaurants (6.6%) and service facilities in nightlife businesses (5.2%). In the matched cohorts, we found no clear disparities in time to admission and clinical prognoses. The epidemic curve for non-Japanese patients showed a small peak in the first wave and no definite waves for the second or third waves. Racial and ethnic minorities were at less risk of severe disease but were at a greater risk of COVID-19 exposure; however, the healthcare system in Japan may provide them with equal opportunities to access inpatient care with Japanese. Further research on their social determinants of health in Japan is required.

Lessons learned from an outbreak of COVID-19 in the head and neck surgery ward of a Japanese cancer center during the sixth wave by Omicron.

INTRODUCTION: We describe a coronavirus disease (COVID-19) outbreak in a cancer center's head and neck surgery ward and the interventions to halt ongoing exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among healthcare workers and patients with cancer. METHODS: Case definition included all healthcare workers and all patients associated to the ward from January 27 to January 31, 2022 with a positive SARS-COV-2 antigen test. This retrospective descriptive study was conducted between January 27, 2022, and February 14, 2022. RESULTS: From January 28, 2022, to February 9, 2022, 84 cases (36 healthcare workers, 48 patients) were screened, and 26 (12 healthcare workers, 14 patients) were identified as SARS-CoV-2-positive. The proportion of healthcare providers who performed aerosol generating procedures on positive patients was 91% for positive cases and 49% for non-cases. Room sharing with patients with COVID-19 was 64% for positive cases and 21% for non-cases (57% vs. 21% with positive tracheostomy patients; 43% vs. 9% with positive cases using a nebulizer; 50% vs. 15% with positive cases requiring sputum suctioning, respectively). Compliance with the universal masking policy for patients was 36% of positive cases and 79% of non-cases. CONCLUSIONS: This is the first report of a nosocomial outbreak of COVID-19 in a head and neck surgery ward during the Omicron pandemic. Notably, there were a high number of positive cases among healthcare workers who performed aerosol generating procedures for positive patients and patients who shared the room with a patient with COVID-19 with the potential to generate aerosols.

Disseminated tuberculosis with paradoxical reactions caused by a Mycobacterium tuberculosis strain belonging to the Indo-Oceanic lineage: An imported case in Japan.

Tuberculosis remains a major public health concern. Millions of tuberculosis cases and associated deaths have been reported worldwide. The Indo-Oceanic lineage Mycobacterium tuberculosis is common in Southeast Asia and causes extrapulmonary lesions. Only a few case studies on this lineage with genetic analysis using whole-genome sequencing have been reported in the literature. We present a case of disseminated tuberculosis, characterized by a variety of extrapulmonary lesions and paradoxical reactions, caused by the Indo-Oceanic lineage M. tuberculosis in a woman in Myanmar. A 22-year-old Burmese woman had arthritis in the right knee, with unknown aetiology, and was referred to our hospital. Computed tomography of the trunk revealed multiple nodular shadows in both lungs; swollen mediastinal lymph nodes; and small, low-density areas in the spleen. M. tuberculosis was detected in the sputum sample, joint aspirate, subcutaneous tumor, and exudate. She experienced a variety of paradoxical reactions together with aggressive tuberculosis dissemination in all areas of the body. Whole-genome sequencing of the DNA of MTB obtained from sputum and the right cervical subcutaneous abscess confirmed the Indo-Oceanic lineage of M. tuberculosis, the predominant strain in Myanmar. The Indo-Oceanic lineage M. tuberculosis causes disseminated tuberculosis all over the body including the periungual region. When patients show unusual symptoms, physicians should consider the introduction of new strains from foreign countries. Genetic analyses of the strains are recommended to define and confirm the lineages.

Change in use of pediatric oral antibiotics in Japan, pre- and post-implementation of an antimicrobial resistance action plan.

BACKGROUND: Most antimicrobials are prescribed to outpatients, making outpatient antibiotic prescription an important target for antibiotic stewardship. A national antimicrobial resistance (AMR) action plan was developed in 2016 by the Japanese government with various antimicrobials steawardship activities for pediatric outpatients. We aimed to evaluate changes in antibiotic use pre- and post-implementation of the AMR action plan. METHODS: All antimicrobials prescribed to pediatric outpatients in Japan from 2011 to 2018 were retrospectively analyzed using data from a national database. Antimicrobials dispensed for patients aged ≤19 years were reviewed. Antimicrobial use was surveyed by age, year of use, type of antimicrobial prescribed, and prescribing facility. Five cities were selected as pilot areas to investigate the variations, based on the clinical specialties of the prescribing physicians. RESULTS: Antimicrobial usage varied with age. Specifically, usage decreased post-AMR in patients aged ≤8 years and increased in those aged >15 years. Further, antimicrobial prescriptions tended to decrease after 2016 in primary care clinics and hospitals. In the pilot areas of the study, 35% of all oral antimicrobials were prescribed in otolaryngology departments, and 8% were prescribed in dermatology clinics. Notably, antimicrobial prescriptions from both departments showed an upward trend from 2011 to 2018. CONCLUSION: The use of antimicrobial agents decreased in children younger than 8 years in pediatric clinics, hospitals, and internal medicine clinics. However, use increased in children older than 15 years and in other specialty clinics. Settings with an increasing use of antimicrobials are potential targets for the next antibiotic stewardship program and should be investigated in detail.

A Matched Case-Case-Control Study of the Impact of Clinical Outcomes and Risk Factors of Patients with IMP-Type Carbapenemase-Producing Carbapenem-Resistant Enterobacteriaceae in Japan.

IMP-type carbapenemase, found in various Gram-negative bacteria, has been increasingly detected worldwide. We aimed to study the outcomes and risk factors for acquisition of IMP-type carbapenemase-producing carbapenem-resistant Enterobacteriaceae (IMP-CRE), as this has not been evaluated in detail. We conducted a matched case-case-control study of patients from whom IMP-CRE isolates were obtained. All patients who tested positive for IMP-CRE were included; they were matched with patients with carbapenem-susceptible Enterobacteriaceae (CSE) and with controls at a ratio of 1:1:2. The risk factors for acquisition for the CRE and CSE groups and mortality rates, which were calculated using multivariate logistic regression models with weighting according to the inverse probability of propensity scores, were compared. In total, 192 patients (96 patients each in the CRE and CSE groups, with 130 Enterobacter cloacae isolates and 62 Klebsiella sp. isolates) were included. The IMP-11 type was present in 43 patients, IMP-1 in 33, and IMP-60 and IMP-66 in 1 each; 31 patients with CRE (32.3%) and 34 with CSE (35.4%) developed infections. Multivariate analysis identified the following independent risk factors: gastrostomy, history of intravenous therapy or hemodialysis, and previous exposure to broad-spectrum ß-lactam antibiotics, including penicillin with ß-lactamase inhibitors, cephalosporins, and carbapenems. In propensity score-adjusted analysis, mortality rates for the CRE and CSE groups were similar (15.0% and 19.5%, respectively). We found that IMP-CRE may not contribute to worsened clinical outcomes, compared to CSE, and gastrostomy, previous intravenous therapy, hemodialysis, and broad-spectrum antimicrobial exposure were identified as risk factors for CRE isolation. Fluoroquinolone and aminoglycosides are potentially useful antibiotics for IMP-CRE infections.

Study Profile of the Tohoku Medical Megabank Community-Based Cohort Study.

BACKGROUND: We established a community-based cohort study to assess the long-term impact of the Great East Japan Earthquake on disaster victims and gene-environment interactions on the incidence of major diseases, such as cancer and cardiovascular diseases. METHODS: We asked participants to join our cohort in the health check-up settings and assessment center based settings. Inclusion criteria were aged 20 years or over and living in Miyagi or Iwate Prefecture. We obtained information on lifestyle, effect of disaster, blood, and urine information (Type 1 survey), and some detailed measurements (Type 2 survey), such as carotid echography and calcaneal ultrasound bone mineral density. All participants agreed to measure genome information and to distribute their information widely. RESULTS: As a result, 87,865 gave their informed consent to join our study. Participation rate at health check-up site was about 70%. The participants in the Type 1 survey were more likely to have psychological distress than those in the Type 2 survey, and women were more likely to have psychological distress than men. Additionally, coastal residents were more likely to have higher degrees of psychological distress than inland residents, regardless of sex. CONCLUSION: This cohort comprised a large sample size and it contains information on the natural disaster, genome information, and metabolome information. This cohort also had several detailed measurements. Using this cohort enabled us to clarify the long-term effect of the disaster and also to establish personalized prevention based on genome, metabolome, and other omics information.

Association between the combined fat mass and fat-free mass index and hypertension: The Tohoku Medical Megabank Community-based Cohort Study.

BACKGROUND: A  higher body fat percentage is associated with hypertension, even in non-obese individuals. The difference in body composition may be related to hypertension. The fat mass index (FMI) and fat-free mass index (FFMI) are proposed indicators of body composition. This study aimed to examine the relationship of a combination of FMI and FFMI with hypertension. METHODS: We conducted a cross-sectional study of 5,058 men and 11,842 women aged ≥ 20 years in the Miyagi Prefecture, northeastern Japan. The FMI and FFMI were calculated as the fat mass and fat-free mass divided by the height squared, respectively. The indices were classified into quartiles and combined into 16 groups. Hypertension was defined as casual blood pressure ≥ 140/90 mmHg and/or self-reported treatment for hypertension. Multivariable logistic regression models, adjusted for potential confounders, were used to assess the relationship of a combination of FMI and FFMI with hypertension. RESULTS: Higher FMI was associated with hypertension in most of the FFMI subgroups. Similarly, a higher FFMI was associated with hypertension in most of FMI subgroups. For men, the association between FFMI and hypertension in the lowest FMI group was not significant. CONCLUSIONS: Reducing the FMI and FFMI may be important in preventing hypertension. For men, the relationship between the FFMI and hypertension in the lowest FMI group might be weak.

Design and Progress of Oral Health Examinations in the Tohoku Medical Megabank Project.

In order to assess the long-term impact of the Great East Japan Earthquake on the oral health of disaster victims and to evaluate gene-environmental interactions in the development of major oral diseases and oral-systemic associations, the oral part of two large-scale genome cohort studies by the Tohoku Medical Megabank Organization (ToMMo), including the Community-based cohort (CommCohort) study and the Birth and Three-Generation cohort (BirThree) study, have been conducted. The study population comprised 32,185 subjects, including 16,886 participants in the CommCohort study and 15,299 participants in the BirThree cohort study, recruited from 2013 to 2017. The oral studies consist of a questionnaire regarding oral hygiene behavior, clinical examinations by dentists, and oral plaque and saliva sampling for microbiome analyses, which were carried out at seven community support centers in Miyagi prefecture. The median age of all participants was 55.0 years, and 66.1% of participants were women. Almost all participants reported that they brushed their teeth more than once a day. The median number of present teeth was 27.0, and the decayed, missing and filled tooth number was 16.0, with a significant difference according to age and sex. The median periodontal pocket and clinical attachment level was 2.48 mm and 4.00 mm, respectively. Periodontal parameters increased significantly according to age, except for the accumulation of dental calculus. The oral part of these extensive cross-sectional studies provides a unique and important platform for future studies on oral health and diseases that elicit through interactions with systemic diseases, lifestyles, life events and genetic backgrounds, and contributes to researches clarifying the long-term effects of disasters on oral health.

Construction of a Meroterpenoid-Like Compounds Library Based on Diversity-Enhanced Extracts.

The structural diversity of natural products and their derivatives have long contributed to the development of new drugs. However, the difficulty in obtaining compounds bearing skeletally novel structures has recently led to a decline of pharmaceutical research into natural products. This paper reports the construction of a meroterpenoid-like library containing 25 compounds with diverse molecular scaffolds obtained from diversity-enhanced extracts. This method constitutes an approach for increasing the chemical diversity of natural-product-like compounds by combining natural product chemistry and diversity-oriented synthesis. Extensive pharmacological screening of the library revealed promising compounds for anti-osteoporotic and anti-lymphoma/leukemia drugs. This result indicates that the use of diversity-enhanced extracts is an effective methodology for producing chemical libraries for the purpose of drug discovery.

Structural basis of HIV inhibition by translocation-defective RT inhibitor 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA).

4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is the most potent nucleoside analog inhibitor of HIV reverse transcriptase (RT). It retains a 3'-OH yet acts as a chain-terminating agent by diminishing translocation from the pretranslocation nucleotide-binding site (N site) to the posttranslocation primer-binding site (P site). Also, facile misincorporation of EFdA-monophosphate (MP) results in difficult-to-extend mismatched primers. To understand the high potency and unusual inhibition mechanism of EFdA, we solved RT crystal structures (resolutions from 2.4 to 2.9 Å) that include inhibition intermediates (i) before inhibitor incorporation (catalytic complex, RT/DNA/EFdA-triphosphate), (ii) after incorporation of EFdA-MP followed by dT-MP (RT/DNAEFdA-MP(P)• dT-MP(N) ), or (iii) after incorporation of two EFdA-MPs (RT/DNAEFdA-MP(P)• EFdA-MP(N) ); (iv) the latter was also solved with EFdA-MP mismatched at the N site (RT/DNAEFdA-MP(P)• EFdA-MP(*N) ). We report that the inhibition mechanism and potency of EFdA stem from interactions of its 4'-ethynyl at a previously unexploited conserved hydrophobic pocket in the polymerase active site. The high resolution of the catalytic complex structure revealed a network of ordered water molecules at the polymerase active site that stabilize enzyme interactions with nucleotide and DNA substrates. Finally, decreased translocation results from favorable interactions of primer-terminating EFdA-MP at the pretranslocation site and unfavorable posttranslocation interactions that lead to observed localized primer distortions.

Histone chaperone CAF-1 mediates repressive histone modifications to protect preimplantation mouse embryos from endogenous retrotransposons.

Substantial proportions of mammalian genomes comprise repetitive elements including endogenous retrotransposons. Although these play diverse roles during development, their appropriate silencing is critically important in maintaining genomic integrity in the host cells. The major mechanism for retrotransposon silencing is DNA methylation, but the wave of global DNA demethylation that occurs after fertilization renders preimplantation embryos exceptionally hypomethylated. Here, we show that hypomethylated preimplantation mouse embryos are protected from retrotransposons by repressive histone modifications mediated by the histone chaperone chromatin assembly factor 1 (CAF-1). We found that knockdown of CAF-1 with specific siRNA injections resulted in significant up-regulation of the retrotransposons long interspersed nuclear element 1, short interspersed nuclear element B2, and intracisternal A particle at the morula stage. Concomitantly, increased histone H2AX phosphorylation and developmental arrest of the majority (>95%) of embryos were observed. The latter was caused at least in part by derepression of retrotransposons, as treatment with reverse transcriptase inhibitors rescued some embryos. Importantly, ChIP analysis revealed that CAF-1 mediated the replacement of H3.3 with H3.1/3.2 at the retrotransposon regions. This replacement was associated with deposition of repressive histone marks, including trimethylation of histone H3 on lysine 9 (H3K9me3), H3K9me2, H3K27me3, and H4K20me3. Among them, H4K20me3 and H3K9me3 seemed to play predominant roles in retrotransposon silencing, as assessed by knockdown of specific histone methyltransferases and forced expression of unmethylatable mutants of H3.1K9 and H4K20. Our data thus indicate that CAF-1 is an essential guardian of the genome in preimplantation mouse embryos by deposition of repressive histone modifications via histone variant replacement.