Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by impaired social communication and restricted repetitive behaviors, yet the contribution of trace elements remains poorly defined. We profiled 21 trace elements in individuals with ASD and identified significantly reduced copper levels, which negatively correlated with social symptom severity. Magnetic resonance imaging revealed decreased white matter volume in ASD, which also correlated with social impairment. To explore the mechanisms, we generated a copper-deficient mouse model that displayed ASD-like behaviors and impaired oligodendrocyte (OL) development. Copper deficiency disrupted hypoxia-inducible factor 1α (HIF1α)-dependent angiogenesis and metabolic regulation in the embryonic brain, leading to oxidative stress, mitochondrial dysfunction, and BCL2 interacting protein 3 (BNIP3)-mediated mitophagy in oligodendrocyte progenitor cells. These processes suppressed mechanistic target of rapamycin kinase (mTOR) signaling, reduced OL-lineage cells, and caused hypomyelination. Restoring mTOR activity rescued OL maturation and improved social behavior in copper-deficient mice. These findings identify a copper-HIF1α-BNIP3-mTOR signaling axis that links trace element imbalance to glial dysfunction and ASD-relevant behavioral phenotypes, providing mechanistic insight into neurodevelopment.

Rett syndrome (RTT) (OMIM: 312750) is a severe neurodevelopmental disorder caused by mutations in the MECP2 gene. Although decreased dendritic morphogenesis has been observed in the brain of RTT patients and mouse models, the molecular mechanisms underlying these dendritic anomalies remain unclear. We have previously shown that MeCP2 facilitates specific microRNA (miRNA) processing by associating with the miRNA microprocessor Drosha complex. In this study, we show that MeCP2 positively regulates dendritic formation via miR-199a , a specific target of the MeCP2-Drosha complex. Overexpression of MeCP2 and miR-199a promotes dendritic development such as increases in dendrite length, branching number, and complexity. In contrast, blocking miR-199a inhibited dendrite formation and abolished enhanced dendritic development induced by MeCP2 expression. We also demonstrate that the decreased dendrite outgrowth observed in MeCP2-deficient neurons could be rescued by miR-199a expression. In addition, we found that miR-199a targets the 3’ untranslated region of quaking (Qki) , a negative regulator of dendritic development, and downregulates its protein expression level. Furthermore, we report an increase in the Qki protein expression level in miR-199a-2 -deficient brains and show that Qki knockdown restores the dendritic morphology of miR-199a-2 -Knockout (KO) neurons. Taken together, these results suggest that the MeCP2/miR-199a/Qki axis is critical for proper dendritic development and its dysregulation contributes to the dendritic pathology in RTT. ### Competing Interest Statement The authors have declared no competing interest.

Background/Objectives: Despite growing interest in oral frailty as a public health issue, no nationwide study has assessed regional differences in oral frailty awareness, and the factors associated with such differences remain unclear. This study investigated regional differences in oral frailty awareness among older adults in Japan and identified the associated individual- and municipal-level factors, focusing on local policy measures and community-based oral health programs. Methods: A cross-sectional analysis was conducted using data from the 2022 wave of the Japan Gerontological Evaluation Study. The analytical sample comprised 20,330 community-dwelling adults aged ≥65 years from 66 municipalities. Awareness of oral frailty was assessed via self-administered questionnaires. Individual- and municipal-level variables were analyzed using multilevel Poisson regression models to calculate prevalence ratios (PRs). Results: Awareness of oral frailty varied widely across municipalities, ranging from 15.3% to 47.1%. Multilevel analysis showed that being male (PR: 1.10), having ≤9 years (PR: 1.10) or 10 to 12 years of education (PR: 1.04), having oral frailty (PR: 1.04), and lacking civic participation (PR: 1.06) were significantly associated with lack of awareness. No significant associations were found with municipal-level variables such as dental health ordinances, volunteer training programs, or population density. Conclusions: The study found substantial regional variation in oral frailty awareness. However, this variation was explained primarily by individual-level characteristics. Public health strategies should focus on enhancing awareness among socially vulnerable groups—especially men, individuals with low educational attainment, and those not engaged in civic activities—through targeted interventions and community-based initiatives.

Background/Objectives: Periodontal disease may progress despite supportive periodontal therapy (SPT), and conventional clinical parameters exhibit limited predictive value. This study evaluated the prognostic utility of measuring the oral fluid lactate dehydrogenase (LD) activity using a chairside test strip to predict disease progression during SPT. Methods: A cohort of 92 patients (33 males and 59 females; median age, 68 years) undergoing SPT at a university clinic in 2023 were followed up for approximately one year. Oral fluid LD activity was measured using a test strip, and clinical periodontal parameters were assessed at baseline and follow-up. Periodontitis progression was defined as ≥4 sites showing a 2 mm increase in the probing pocket depth, which reached ≥4 mm. Receiver operating characteristic analyses and stepwise logistic regression were used to evaluate the predictive performance of oral fluid LD activity and develop a multivariate model. Results: Seventeen patients (18.5%) developed progressive periodontitis. Progressive cases demonstrated significantly higher baseline LD activity and periodontal parameters. The optimal cutoff value for LD activity was 3.5, yielding a sensitivity, specificity, and negative predictive value of 1.00, 0.53, and 1.00, respectively. Logistic regression identified oral fluid LD and medications as independent predictors, with the multivariate model achieving an area under the curve of 0.785. Conclusions: Oral fluid LD activity measured using the test strip provided prognostic information for periodontitis progression during SPT. Incorporating LD with information obtained from medical interviews did not markedly enhance the predictive accuracy. This rapid and noninvasive method may facilitate risk-based patient management and personalized supportive care.

The purpose of this study was to investigate the association between salivary lactate dehydrogenase (LD) levels, assessed using a test kit, and the community periodontal index (CPI) and to determine the feasibility and reliability of the test kit for screening periodontal disease in adults. The study included 205 patients (58.5

Background: Salivary lactate dehydrogenase (LD) levels are a feasible and useful parameter for screening periodontal diseases. The periodontal inflamed surface area (PISA) is useful to clinically assess periodontal diseases. However, PISA is difficult to calculate and PISA-compatible screening kits are required. We aimed to investigate the association between salivary LD levels, using a test kit, and PISA and PISA-Japanese and determine the feasibility and reliability of the salivary LD test kit for evaluation of periodontal status. Methods: This study included 110 patients (66.4% female, median and 25-75 percentiles of age were 66.5 and 53.0-75.0 years, respectively) who visited the Dental University Clinic in Japan. Resting saliva samples were collected from each participant and LD levels were evaluated in real time using a kit featuring an integer scale ranging from 1 to 10. PISA and PISA-Japanese were calculated using periodontal parameters. Results: The median salivary LD level was 4.0. The medians of PISA and PISA-Japanese were 46.9 and 61.0, respectively. Salivary LD levels were positively correlated with the bleeding on probing rate (r = 0.626, p < 0.001), PISA (r = 0.560, p < 0.001), and PISA-Japanese (r = 0.581, p < 0.001). Conclusions: Our results suggest that salivary LD levels assessed using the salivary LD kit showed a significantly positive correlation with PISA and PISA-Japanese. In addition, we developed the PISA estimation formula using salivary LD levels measured with a test kit, sex, and age.

How group 3 innate lymphoid cells (ILC3s) regulate mucosal protection in the presence of T cells remains poorly understood. Here, we examined ILC3 function in intestinal immunity using ILC3-deficient mice that maintain endogenous T cells, T helper 17 (TH17) cells, and secondary lymphoid organs. ILC3s were dispensable for generation of TH17 and TH22 cell responses to commensal and pathogenic bacteria, and absence of ILC3s did not affect IL-22 production by CD4 T cells before or during infection. However, despite the presence of IL-22-producing T cells, ILC3s and ILC3-derived IL-22 were required for maintaining homeostatic functions of the intestinal epithelium. T cell-sufficient, ILC3-deficient mice were capable of pathogen clearance and survived infection with a low dose of Citrobacter rodentium. However, ILC3s promoted pathogen tolerance at early time points of infection by activating tissue-protective immune pathways. Consequently, ILC3s were indispensable for survival after high-dose infection. Our results demonstrate a context-dependent role for ILC3s in immune-sufficient animals and provide a blueprint for uncoupling of ILC3 and TH17 cell functions.

We aimed to investigate the relationship between the risk of oral frailty and awareness of oral frailty among Japanese adults in an adult dental health field study conducted in Kanagawa Prefecture. Questionnaire data from a total of 5051 individuals (1907 males, 3144 females; mean age; 59.9 years) were used. The risk of oral frailty was assessed using the Oral Frailty Index-8. Of the participants, 1418 (28.1%) had a high risk of oral frailty and 1495 (29.6%) had knowledge of oral frailty. Logistic regression analysis indicated that the risk of oral frailty was significantly associated with awareness of oral frailty. We further found that awareness of oral frailty was significantly related to gender (female), age (20–39 compared to 70–79, ≥ 80), residential areas (Yokohama compared to Kawasaki, Sagamihara), exercise habits (yes), eating a balanced diet (yes), consciousness of oral health (yes), risk of oral frailty (low) and outpatient category (hospital visit). For groups with low levels of awareness obtained from the results of this study, it is necessary to consider the means of accessibility and increase awareness further.

Oral microbiota play a pivotal role in maintaining homeostasis, safeguarding the oral cavity, and preventing the onset of disease. Oral dysbiosis has the potential to trigger pro-inflammatory effects and immune dysregulation, which can have a negative impact on systemic health. It is regarded as a key etiological factor for periodontitis. The emergence and persistence of oral dysbiosis have been demonstrated to mediate inflammatory pathology locally and at distant sites. The heightened inflammation observed in oral dysbiosis is dependent upon the secretion of interleukin-17A (IL-17A) by various innate and adaptive immune cells. IL-17A has been found to play a significant role in host defense mechanisms by inducing antibacterial peptides, recruiting neutrophils, and promoting local inflammation via cytokines and chemokines. This review seeks to present the current knowledge on oral dysbiosis and its prevention, as well as the underlying role of IL-17A in periodontitis induced by oral dysbiosis and its impact on systemic inflammatory disease.

Autism spectrum disorder (ASD) is a heterogeneous disorder characterized by impaired social communication and restricted repetitive behaviors, however the biological mechanisms remain unclear. Although trace elements play essential roles in the living body, it is unclear how alterations of trace elements in ASD are involved in pathogenesis. Here we analyzed the plasma metallome and identified the alterations of 11 elements in individuals with ASD. The copper decrease was negatively correlated with ASD symptom scores. A copper-deficient mouse model reflecting the condition showed ASD-like behaviors and impaired oligodendrocyte development. In copper-deficient mice, mechanistic target of rapamycin (mTOR) signaling was reduced, and its activation by agonist improved social impairment and oligodendrocyte developmental defects. Supporting these results, white matter volumes were negatively correlated with social symptoms in individuals with ASD. Our results demonstrate that copper-deficiency contributes to ASD by causing oligodendrocytes impairment via mTOR signaling. Our findings indicate that the effects of copper-deficiency and mTOR imbalance are relevant to the pathogenesis of ASD and are potential therapeutic targets. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was founded by The Japan Agency for Medical Research and Development (AMED) Translational Research Grant Seeds A140 (NU, SS), AMED-CREST 22gm1510009h0001 (MM), AMED-PRIM 21wm04250XXs0101 (MM), AMED 21uk1024002s0201 (MM), 20gm6310015h0001 (MM), The Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research (B) 23H02837 (NU), 19H03581 (HM), 20H03604 (MM), JSPS Grant-in-Aid for Scientific Research (C) 20K06872 (NU), JSPS Grant-in-Aid for Early-Career Scientists 23K14443 (MD), JSPS Grant-in-Aid for Challenging Research (Exploratory) 19K21754 (HM), Uehara Memorial Foundation (NU), Takeda Science Foundation (NU), Naito Foundation (NU) Mochida Memorial Foundation for Medical and Pharmaceutical Research (NU), Inamori Foundation (NU), SENSHIN Medical Research Foundation (NU), Osaka Medical Research Foundation for Intractable Diseases (NU, MD), MEI Grant supported by Osaka University (NU), and Osaka University Medical Doctor Scientist Training Program (NN). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: All procedures were approved by the Ethics Committee of Osaka University (#19394), University of Fukui (#20200112), and Nara Medical University (#1319), and were conducted in accordance with the Ethical Guidelines for Medical and Health Research Involving Human Subjects of the Ministry of Health, Labour and Welfare of Japan. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data supporting the findings of this study are available from the corresponding author upon reasonable request.

Some studies have reported a significant association between periodontal condition and obesity status. We hypothesized that visceral fat area (VFA) and subcutaneous fat area (SFA) volumes might be correlated with periodontal condition. The purpose of the present cross-sectional study was to investigate the association between periodontal condition and fat distribution in Japanese adults. A total of 158 participants, aged 35–74 years, underwent a health check-up including fat distribution and oral examinations. All of the participants underwent magnetic resonance imaging to quantify VFA and SFA. Periodontal condition was evaluated using the periodontal pocket depth (PPD) and clinical attachment level. The VFA volumes differed among the PPD score and clinical attachment level (CAL) code groups. On the other hand, no significant differences in SFA volume were observed among different periodontal conditions. Multiple regression analysis showed that VFA was positively correlated with a greater CAL (standardized coefficient β = 0.123, p = 0.009), but not with a greater PPD score. A larger VFA was positively associated with a greater CAL in Japanese adults, whereas no association was found between SFA and periodontal condition.

The occupational environment is an important factor for oral health because people spend a long time in the workplace throughout their lives and are affected by work-related stress and occupational health policies. This study aimed to review evidence for the association between occupation and oral health status and behaviors. A literature search of PubMed was conducted from February to May 2022, as well as a manual search analyzing the article origins. Articles were screened and considered eligible if they met the following criteria: (1) published in English; (2) epidemiological studies on humans; and (3) examined the association between occupation and oral health status and behaviors. All 23 articles identified met the eligibility criteria. After full-text assessments, ten articles from Japan were included in this review: four on the association between occupation and dental caries, three on occupation and periodontal disease, two on occupation and tooth loss, and one on occupation and oral health behaviors. An association was apparent between occupation, oral health status and behaviors among Japanese workers. In particular, skilled workers, salespersons, and drivers who work longer hours and often on nightshifts, tended to have poor oral health.

The evolution of humans brought about a co-occurring evolution of the human brain, which is far larger and more complex than that of many other organisms. The brain has evolved characteristically in humans in many respects, including macro-and micro-anatomical changes in the brain structure, changes in gene expression, and cell populations and ratios. These characteristics are essential for the execution of higher functions, such as sociality, language, and cognition, which express humanity, and are thought to have been acquired over evolutionary time. However, with the acquisition of higher functions also comes the risk of the disease in which they fail. This review focuses on human brain evolution and neurodevelopmental disorders (NDDs) and discusses brain development, molecular evolution, and human brain evolution. Discussing the potential for the development and pathophysiology of NDDs acquired by human brain evolution will provide insights into the acquisition and breakdown of higher functions from a new perspective.

Cite this article: Yonenaga T, Azuma T, Iwai K, Irie K, Watanabe K, et al. Association of Elevated C-reactive Protein Levels and Periodontal Status in Japanese Adults with and without Obesity. Ann Dent Oral Health. 2021; 4(2): 1040. *Corresponding Author(s): Takaaki Tomofuji Department of Community Oral Health, School of Dentistry, Asahi University, Mizuho, Gifu 501-0296, Japan. Tel: +81-58-329-1496; Email: tomofu@dent.asahi-u.ac.jp Abstract

Rett syndrome (RTT) is a severe neurological disorder, with impaired brain development caused by mutations in MECP2; however, the underlying mechanism remains elusive. We know from previous work that MeCP2 facilitates the processing of a specific microRNA, miR-199a, by associating with the Drosha complex to regulate neuronal functions. Here, we show that the MeCP2/miR-199a axis regulates neural stem/precursor cell (NS/PC) differentiation. A shift occurs from neuronal to astrocytic differentiation of MeCP2- and miR-199a-deficient NS/PCs due to the upregulation of a miR-199a target, Smad1, a downstream transcription factor of bone morphogenetic protein (BMP) signaling. Moreover, miR-199a expression and treatment with BMP inhibitors rectify the differentiation of RTT patient-derived NS/PCs and development of brain organoids, respectively, suggesting that facilitation of BMP signaling accounts for the impaired RTT brain development. Our study illuminates the molecular pathology of RTT and reveals the MeCP2/miR-199a/Smad1 axis as a potential therapeutic target for RTT.

During brain development, neural stem cells (NSCs) initially produce neurons and change their fate to generate glias. While the regulation of neurogenesis is well characterized, specific markers for glial precursor cells (GPCs) and the master regulators for gliogenesis remain unidentified. Accumulating evidence suggests that RNA-binding proteins (RBPs) have significant roles in neuronal development and function, as they comprehensively regulate the expression of target genes in a cell-type-specific manner. We systematically investigated the expression profiles of 1,436 murine RBPs in the developing mouse brain and identified quaking (Qk) as a marker of the putative GPC population. Functional analysis of the NSC-specific Qk-null mutant mouse revealed the key role of Qk in astrocyte and oligodendrocyte generation and differentiation from NSCs. Mechanistically, Qk upregulates gliogenic genes via quaking response elements in their 30 untranslated regions. These results provide crucial directions for identifying GPCs and deciphering the regulatory mechanisms of gliogenesis from NSCs.

Deep and subcortical white matter hyperintensity (DSWMH) lesions are a small-vessel disease of the brain. The aim of this cross-sectional study was to investigate the relationship between DSWMH lesions and periodontal status in Japanese adults who participated in a health check. We enrolled 444 consecutive participants (mean age, 54.5 years) who received both brain and oral health evaluation services at the Asahi University Hospital. Magnetic resonance imaging was used to detect DSWMH lesions. Periodontal status was assessed using the community periodontal index. Of the study participants, 215 (48.4%) had DSWMH lesions. Multivariate logistic regression showed that the presence of DSWMH lesions was significantly related to age ≥ 65 years (vs. < 65 years, odds ratio [OR] = 2.984, 95% confidence interval [CI] = 1.696–5.232), systolic blood pressure ≥ 140 mmHg (vs. < 140 mmHg, OR = 2.579, 95% CI = 1.252–5.314), the presence of ≥ 28 teeth (vs. < 28 teeth, OR = 0.635, 95% CI = 0.420–0.961), and probing pocket depth (PPD) ≥ 6 mm (vs. PPD < 6 mm, OR = 1.948, 95% CI = 1.132–3.354) after adjustment for confounding factors. Having PPD ≥ 6 mm may be a risk factor for DSWMH lesions in Japanese adults.

Non-alcoholic fatty liver disease (NAFLD) is a major global health problem.The aim of the present cross-sectional study was to investigate the relationship between eating quickly and NAFLD in Japanese adults.A total of 8556 participants underwent a health checkup.Abdominal ultrasonography was applied to diagnose NAFLD, and information on eating speed was obtained using a self-administrated questionnaire.Of the study participants, 2570 (30.0%) had ultrasound diagnosed NAFLD.The participants who reported eating quickly had a higher prevalence of NAFLD when compared to those who did not report eating quickly.The presence of NAFLD was significantly associated with male sex (odds ratio [OR] = 3.163, 95% confidence interval [CI] = 2.800 -3.573), age ≥ 65 years (OR = 1.426, 95%CI = 1.076 -1.889), high body mass index (≥ 25 kg/m 2 ; OR = 9.615, 95%CI = 8.511 -10.863), hypertension (OR = 1.659, 95%CI = 1.424 -1.931), high hemoglobin A1c values (≥ 6.5%; OR = 4.096, 95%CI = 3.080 -5.446), the presence of regular exercise habits (OR = 0.605, 95%CI = 0.522 -0.701), and eating quickly (OR = 1.146, 95%CI = 1.023 -1.283) after adjusting for confounding factors.These results indicated that lifestyle factors, including eating quickly, is positively associated with NAFLD in Japanese adults independently of overweight and obesity.