Alternative polyadenylation determines the functional landscape of inverted Alu repeats.

Inverted Alu repeats (IRAlus) are abundantly found in the transcriptome, especially in introns and 3' untranslated regions (UTRs). Yet, the biological significance of IRAlus embedded in 3' UTRs remains largely unknown. Here, we find that 3' UTR IRAlus silences genes involved in essential signaling pathways. We utilize J2 antibody to directly capture and map the double-stranded RNA structure of 3' UTR IRAlus in the transcriptome. Bioinformatic analysis reveals alternative polyadenylation as a major axis of IRAlus-mediated gene regulation. Notably, the expression of mouse double minute 2 (MDM2), an inhibitor of p53, is upregulated by the exclusion of IRAlus during UTR shortening, which is exploited to silence p53 during tumorigenesis. Moreover, the transcriptome-wide UTR lengthening in neural progenitor cells results in the global downregulation of genes associated with neurodegenerative diseases, including amyotrophic lateral sclerosis, via IRAlus inclusion. Our study establishes the functional landscape of 3' UTR IRAlus and its role in human pathophysiology.

Metabolic flux from the Krebs cycle to glutamate transmission tunes a neural brake on seizure onset.

Kohlschütter-Tönz syndrome (KTS) manifests as neurological dysfunctions, including early-onset seizures. Mutations in the citrate transporter SLC13A5 are associated with KTS, yet their underlying mechanisms remain elusive. Here, we report that a Drosophila SLC13A5 homolog, I'm not dead yet (Indy), constitutes a neurometabolic pathway that suppresses seizure. Loss of Indy function in glutamatergic neurons caused "bang-induced" seizure-like behaviors. In fact, glutamate biosynthesis from the citric acid cycle was limiting in Indy mutants for seizure-suppressing glutamate transmission. Oral administration of the rate-limiting α-ketoglutarate in the metabolic pathway rescued low glutamate levels in Indy mutants and ameliorated their seizure-like behaviors. This metabolic control of the seizure susceptibility was mapped to a pair of glutamatergic neurons, reversible by optogenetic controls of their activity, and further relayed onto fan-shaped body neurons via the ionotropic glutamate receptors. Accordingly, our findings reveal a micro-circuit that links neural metabolism to seizure, providing important clues to KTS-associated neurodevelopmental deficits.

The E3 ubiquitin ligase adaptor Tango10 links the core circadian clock to neuropeptide and behavioral rhythms.

Circadian transcriptional timekeepers in pacemaker neurons drive profound daily rhythms in sleep and wake. Here we reveal a molecular pathway that links core transcriptional oscillators to neuronal and behavioral rhythms. Using two independent genetic screens, we identified mutants of Transport and Golgi organization 10 (Tango10) with poor behavioral rhythmicity. Tango10 expression in pacemaker neurons expressing the neuropeptide PIGMENT-DISPERSING FACTOR (PDF) is required for robust rhythms. Loss of Tango10 results in elevated PDF accumulation in nerve terminals even in mutants lacking a functional core clock. TANGO10 protein itself is rhythmically expressed in PDF terminals. Mass spectrometry of TANGO10 complexes reveals interactions with the E3 ubiquitin ligase CULLIN 3 (CUL3). CUL3 depletion phenocopies Tango10 mutant effects on PDF even in the absence of the core clock gene timeless Patch clamp electrophysiology in Tango10 mutant neurons demonstrates elevated spontaneous firing potentially due to reduced voltage-gated Shaker-like potassium currents. We propose that Tango10/Cul3 transduces molecular oscillations from the core clock to neuropeptide release important for behavioral rhythms.

ZNF598 co-translationally titrates poly(GR) protein implicated in the pathogenesis of C9ORF72-associated ALS/FTD.

C9ORF72-derived dipeptide repeat proteins have emerged as the pathogenic cause of neurodegeneration in amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). However, the mechanisms underlying their expression are not fully understood. Here, we demonstrate that ZNF598, the rate-limiting factor for ribosome-associated quality control (RQC), co-translationally titrates the expression of C9ORF72-derived poly(GR) protein. A Drosophila genetic screen identified key RQC factors as potent modifiers of poly(GR)-induced neurodegeneration. ZNF598 overexpression in human neuroblastoma cells inhibited the nuclear accumulation of poly(GR) protein and decreased its cytotoxicity, whereas ZNF598 deletion had opposing effects. Poly(GR)-encoding sequences in the reporter RNAs caused translational stalling and generated ribosome-associated translation products, sharing molecular signatures with canonical RQC substrates. Furthermore, ZNF598 and listerin 1, the RQC E3 ubiquitin-protein ligase, promoted poly(GR) degradation via the ubiquitin-proteasome pathway. An ALS-relevant ZNF598R69C mutant displayed loss-of-function effects on poly(GR) expression, as well as on general RQC. Moreover, RQC function was impaired in C9-ALS patient-derived neurons, whereas lentiviral overexpression of ZNF598 lowered their poly(GR) expression and suppressed proapoptotic caspase-3 activation. Taken together, we propose that an adaptive nature of the RQC-relevant ZNF598 activity allows the co-translational surveillance to cope with the atypical expression of pathogenic poly(GR) protein, thereby acquiring a neuroprotective function in C9-ALS/FTD.

Serine metabolism in the brain regulates starvation-induced sleep suppression in Drosophila melanogaster.

Sleep and metabolism are physiologically and behaviorally intertwined; however, the molecular basis for their interaction remains poorly understood. Here, we identified a serine metabolic pathway as a key mediator for starvation-induced sleep suppression. Transcriptome analyses revealed that enzymes involved in serine biosynthesis were induced upon starvation in Drosophila melanogaster brains. Genetic mutants of astray (aay), a fly homolog of the rate-limiting phosphoserine phosphatase in serine biosynthesis, displayed reduced starvation-induced sleep suppression. In contrast, a hypomorphic mutation in a serine/threonine-metabolizing enzyme, serine/threonine dehydratase (stdh), exaggerated starvation-induced sleep suppression. Analyses of double mutants indicated that aay and stdh act on the same genetic pathway to titrate serine levels in the head as well as to adjust starvation-induced sleep behaviors. RNA interference-mediated depletion of aay expression in neurons, using cholinergic Gal4 drivers, phenocopied aay mutants, while a nicotinic acetylcholine receptor antagonist selectively rescued the exaggerated starvation-induced sleep suppression in stdh mutants. Taken together, these data demonstrate that neural serine metabolism controls sleep during starvation, possibly via cholinergic signaling. We propose that animals have evolved a sleep-regulatory mechanism that reprograms amino acid metabolism for adaptive sleep behaviors in response to metabolic needs.

Soft tissue expander for vertically atrophied alveolar ridges: Prospective, multicenter, randomized controlled trial.

OBJECTIVES: Conventional guided bone regeneration (GBR) limits the amount of bone graft due to limited soft tissue expansion. We hypothesize that the use of tissue expander will successfully augment soft tissue prior to bone graft, allowing for sufficient amount of grafting which will lead to a more stable and effective vertical bone graft. The authors aimed to evaluate effectiveness of the novel self-inflating tissue expander for vertical augmentation in terms of soft tissue expansion, clinical outcomes, and related complications. MATERIAL AND METHODS: A prospective, multicenter, randomized controlled trial was performed on patients requiring vertical augmentation. For experimental group patients, the tissue expander was subperiosteally implanted and followed by a tunneling bone graft without full flap reflection. Control patients underwent conventional vertical GBR. Primary objectives were to evaluate the dimensional changes of soft tissue and radiographic vertical bone gain and retention. As a secondary outcome, clinical complications and thickness changes of expanded overlying tissue were assessed and analyzed. RESULTS: Twenty-three patients in each group were included. During a 4-week expansion, two of the experimental group showed over-expansion and one showed mucosal perforation associated with previous severe scars. The other patients showed uneventful expansion and mean tissue augmentation was 6.88 ± 1.64 mm vertically. Ultrasonographic measurements of overlying gingiva revealed no thinning after tissue expansion (p > .05). Significantly higher vertical bone gain was shown in the experimental group (5.12 ± 1.25 mm) compared with that in the control patients (4.22 ± 1.15 mm; p < .05). After a 6-month retention period, the mean vertical bone measurement of the controls had decreased to 1.90 mm (55.0% reduction), which was a significantly greater decrease than that in the experimental group (mean 3.55 mm, 30.7% reduction; p < .05). CONCLUSION: Our results demonstrated the effectiveness of tissue expanders followed by tunneling bone graft for vertical augmentation; however, studies comparing the two techniques without tissue expanders are needed to elucidate the net effect of tissue expansion.

Characteristics of Local Delivery Agents for Treating Peri-Implantitis on Dental Implant Surfaces: A Preclinical Study.

Local delivery agents (LDAs) are widely used in peri-implantitis treatments. The aim of this study was to identify LDAs remaining on the dental implant surfaces and to analyze the components of these residues after applying various cleaning methods. Implants were prepared with a sand-blasted, large-grit, acid-etched surface. Four kinds of LDAs were applied on the implant surfaces: chlorhexidine gel (group 2), tetracycline solution (group 3), and 2 kinds of minocycline hydrochloride agents (groups 4 and 5). Group 1 received normal saline as a control. Two cleaning methods were applied for different durations as follows: (1) running distilled water for 10 seconds (subgroup A), 5 minutes (subgroup B), and 15 minutes (subgroup C); and (2) water spray of a dental-unit chair for 10 seconds (subgroup D) and 5 minutes (subgroup E). Scanning electron microscopy and energy-dispersive x-ray spectroscopy were used to analyze the surface morphology and residue components for all implants. The amount of LDA removed from the implant surfaces in groups 1, 2, 3, and 5 increased with the cleaning duration and pressure. However, Minocline remained coated on the implant surfaces in group 4 under all cleaning conditions. Minocline could not be cleaned off well by water due to its hydrophobicity. Therefore, directly using this agent on implant surfaces with peri-implantitis should be carefully considered. The presence of LDA residues without drug efficacies on implant surfaces might interfere with reosseointegration and act as a reservoir of microorganisms.

Combining virtual model and cone beam computed tomography to assess periodontal changes after anterior tooth movement.

BACKGROUND: Orthodontic force may affect not only periodontal ligaments, but also the alveoloar bone and the gingiva according to the type of tooth movements. The authors assessed changes in gingival thickness (GT) and alveolar bone thickness (ABT) after orthodontic treatment using a new method. METHODS: This study included 408 teeth (208 central incisors, 200 lateral incisors) from the upper and lower 4 anterior teeth of 52 patients who had completed orthodontic treatment. GT and ABT were measured using virtual casts fabricated from impressions and cone beam computed tomography (CBCT). Two sectioned images of every tooth axis were acquired by partitioning each tooth with a line connecting the midpoint of the incisal edge to the midpoint of the cementoenamel junction in the virtual models and the root apex in CBCT images. After superimposing the two sectioned images, GT and ABT were measured before and after orthodontic tooth movement. Correlations between GT and ABT before and after treatment, and changes in GT and ABT associated with sex, tooth arch, tooth position, orthognathic surgery, and tooth inclination and rotation were assessed. RESULTS: Before orthodontic treatment, GT and ABT were significantly correlated. Patients who underwent orthognathic surgery exhibited an increase in GT thickness compared with those who did not. ABT was significantly decreased in proclined teeth and in rotated teeth. CONCLUSIONS: GT and ABT can be affected by the nature of tooth movement and can be accurately assessed by comparing sectioned CBCT images and virtual models.

Validity assessment of quantitative light-induced fluorescence-digital (QLF-D) for the dental plaque scoring system: a cross-sectional study.

BACKGROUND: The aim of this study was to analyze the correlation between the dental plaque indices measured using quantitative light-induced fluorescence-digital (QLF-D) and conventional clinical indices that assess gingival status. METHODS: From among the patients who visited Ewha Womans University Mokdong Hospital, 33 adults in their 20s who had relatively even teeth were selected for full-mouth QLF-D imaging. The images were used to analyze the QLF-D score and the QLF-D ΔR score. As clinical indices, the gingival index (GI), bleeding on probing (BOP), probing pocket depth (PPD), and patient hygiene performance (PHP) index were measured. The correlations between the QLF-D score and QLF-D ΔR score and each clinical index were analyzed. Analyses were performed comparing the indices of maxillary and mandibular teeth, the teeth on right and left sides of the mouth, anterior and posterior teeth, and buccal and lingual surfaces of each tooth. Pearson's correlation analysis was conducted (p < 0.05). RESULTS: The mean full-mouth QLF-D score was highly correlated with the GI, BOP, PPD, PHP index (p < 0.01). The mean full-mouth QLF-D score showed the highest correlation with GI (r = 0.749) and the lowest correlation with PPD (r = 0.683). The correlations between the QLF-D score were higher in the mandible than in the maxilla and in the anterior teeth than in the posterior teeth, while no significant differences were seen between the buccal and lingual surfaces of tooth. CONCLUSIONS: This study concluded that the correlations between the plaque indices measured for each tooth surface area using QLF-D and the clinical indices assessed were significantly high, and it allowed objective determination of the gingival status. Therefore, the plaque index measured using QLF-D may be used as an alternative to supplement the shortcomings of conventional clinical indices for educating patients about plaque control and continued patient oral care.

The novel gene twenty-four defines a critical translational step in the Drosophila clock.

Daily oscillations of gene expression underlie circadian behaviours in multicellular organisms. While attention has been focused on transcriptional and post-translational mechanisms, other post-transcriptional modes have been less clearly delineated. Here we report mutants of a novel Drosophila gene twenty-four (tyf) that show weak behavioural rhythms. Weak rhythms are accompanied by marked reductions in the levels of the clock protein Period (PER) as well as more modest effects on Timeless (TIM). Nonetheless, PER induction in pacemaker neurons can rescue tyf mutant rhythms. TYF associates with a 5'-cap-binding complex, poly(A)-binding protein (PABP), as well as per and tim transcripts. Furthermore, TYF activates reporter expression when tethered to reporter messenger RNA even in vitro. Taken together, these data indicate that TYF potently activates PER translation in pacemaker neurons to sustain robust rhythms, revealing a new and important role for translational control in the Drosophila circadian clock.

Chemokine in inflamed periodontal tissues activates healthy periodontal-ligament stem cell migration.

AIM: The present study aimed to characterize the expression pattern of chemokines obtained from inflamed periodontal defects and to determine the characteristics of human periodontal-ligament stem cells (hPDLSCs) migrated by each specific chemokine. MATERIALS AND METHODS: Both inflamed and healthy periodontal tissues were obtained from periodontitis patients (n = 11), and the chemokine expression levels were analyzed. The periodontal-tissue-specific chemokines were applied to healthy hPDLSCs from extracted teeth (n = 3), with FGF-2 acting as a positive control. Cells were separated by selected chemokines using transwell method into migrated/unmigrated hPDLSCs. The characteristics of the hPDLSC subpopulation recruited by each chemokine were assessed, and gene expression pattern was analyzed by microarray. RESULTS: Chemokines were categorized into three groups by specific patterns of "appearing," "increasing," and "decreasing/disappearing" from healthy to inflamed tissues. A representative chemokine from each group enhanced the capacities for colony formation and osteogenic/adipogenic differentiation while maintaining the surface markers of hPDLSCs. RANTES/CCL5 significantly increased the cellular migration of hPDLSCs, via enhancement of signaling pathways, regulation of the actin skeleton, and focal adhesion. CONCLUSION: The present study found a specific chemokine profile induced by inflammation in periodontal tissues, with RANTES/CCL5 appearing to play a role in the migration of hPDLSCs into inflammatory periodontal lesions.

Mechanical Complication Rates and Optimal Horizontal Distance of the Most Distally Positioned Implant-Supported Single Crowns in the Posterior Region: A Study with a Mean Follow-Up of 3 Years.

PURPOSE: The purpose of this retrospective study was to determine the 3-year mechanical complication rates of the most distally positioned implant-supported single crowns (ISSCs) in the posterior region, and how these complication rates are affected by several clinical factors (i.e., gender, mean age, horizontal distance [HD], position in the jaw, placement location, duration of functional loading, clinical crown-to-implant length ratio [C/I ratio], and crown height space of the implant). MATERIALS AND METHODS: The mechanical complications (i.e., abutment screw loosening [ASL], abutment screw fracture [ASF], and ceramic fracture [CF]) associated with the implants were identified by examining the patients' treatment records, clinical photographs, and intraoral periapical radiographs. Statistical analyses were performed using chi-square and Student's t-test to identify the relationship between various clinical factors and the mechanical complication rates. Receiver operating characteristics analysis was conducted to determine the optimal cut-off value for the HD between the most distally positioned ISSCs and the mesially adjacent natural tooth beyond which complications occur. RESULTS: The study inclusion criteria were met by 183 patients who had undergone implant surgery in the period 2004 to 2011, involving a total of 221 implant treatments. Mechanical complications were present in 40 (18.1%) of the 221 investigated ISSCs. ASL was the most common complication (n = 28, 12.7%), followed in order by CF (n = 9, 4.1%) and ASF (n = 3, 1.4%). Repeated ASL and CF occurred in four (1.8%) and two (0.9%) implants, respectively. The mechanical complication rates differed significantly between implants with different HDs (p = 0.009) and clinical C/I ratios (p = 0.019); however, there was no significant association between the other clinical factors and the mechanical complication rates. CONCLUSION: Within the limitations of this study, it appears that the incidence of mechanical complications is higher for the most distally positioned ISSCs in the posterior region than for those positioned at other sites. Furthermore, since the rate of mechanical complications increases with increasing HD, an HD of 3.7 mm or less is recommended.

Identification of the rare compound heterozygous variants in the NEB gene in a Korean family with intellectual disability, epilepsy and early-childhood-onset generalized muscle weakness.

We examined a Korean family with complex phenotypes characterized by intellectual disability, epilepsy and early-childhood-onset generalized muscle weakness. Since we did not find any abnormality using several conventional genetic tests for detection of chromosomal aberrations, gene copy number variations and mitochondrial gene mutations, we aimed to identify disease-causing genetic alteration(s) in this family. We conducted whole-exome sequencing (WES) in this family. After filtering the WES data, we compared five exome sequences of two affected siblings, one unaffected sibling and the unaffected parents, and we determined the allele frequency of the identified variants in an Asian population. Finally, we selected one candidate variant pair which is unique in the patients and corresponds to an autosomal recessive genetic model. The two affected siblings had the same compound heterozygous variation in the NEB gene encoding nebulin, which was composed of two different missense variants: c.2603T>C (p.L868P) in exon 27 and c.21340C>T (p.R7114W) in exon 143. We confirmed these variations by Sanger sequencing. On the basis of the fundamental role of nebulin in the brain and skeletal muscles, we concluded that this compound heterozygous NEB variation may be a sound candidate for the disease-causing mutation in this family. Since the patients are characterized by generalized muscle weakness together with neurodevelopmental phenotypes, it is suggested that NEB mutations could manifest more diverse phenotypes than those previously described.

Identification of dental implant systems from low-quality and distorted dental radiographs using AI trained on a large multi-center dataset.

Most artificial intelligence (AI) studies have attempted to identify dental implant systems (DISs) while excluding low-quality and distorted dental radiographs, limiting their actual clinical use. This study aimed to evaluate the effectiveness of an AI model, trained on a large and multi-center dataset, in identifying different types of DIS in low-quality and distorted dental radiographs. Based on the fine-tuned pre-trained ResNet-50 algorithm, 156,965 panoramic and periapical radiological images were used as training and validation datasets, and 530 low-quality and distorted images of four types (including those not perpendicular to the axis of the fixture, radiation overexposure, cut off the apex of the fixture, and containing foreign bodies) were used as test datasets. Moreover, the accuracy performance of low-quality and distorted DIS classification was compared using AI and five periodontists. Based on a test dataset, the performance evaluation of the AI model achieved accuracy, precision, recall, and F1 score metrics of 95.05%, 95.91%, 92.49%, and 94.17%, respectively. However, five periodontists performed the classification of nine types of DISs based on four different types of low-quality and distorted radiographs, achieving a mean overall accuracy of 37.2 ± 29.0%. Within the limitations of this study, AI demonstrated superior accuracy in identifying DIS from low-quality or distorted radiographs, outperforming dental professionals in classification tasks. However, for actual clinical application of AI, extensive standardization research on low-quality and distorted radiographic images is essential.

Risk factors for the failure of re-implanted dental implants: A 20-year retrospective study.

BACKGROUND: Re-implantation of failed implants is common to maintain the original prosthetic plan; however, it may not always be ideal due to various factors. Few studies have thoroughly investigated the outcomes of re-implanted implants, while considering factors that can enhance their survival rates. Therefore, this study aimed to identify the risk factors that may contribute to the refailure of implants placed the second time by analyzing previously failed implants and evaluating their survival. METHODS: Of 10,666 dental implants placed in 4063 patients at the Department of Periodontics of the Gangneung-Wonju National University Dental Hospital between December 1999 and March 2021, 259 failed implants in 170 patients were evaluated through clinical and radiographic records for patient-, surgical-, implant-, and prosthesis-related factors; survival analysis was conducted for implants that met the inclusion criteria. RESULTS: Of the 259 failed implants, 80 second-time-placed implants met the inclusion criteria. Survival analysis showed that the 1-year survival rate of second-time-placed implants was 88.1%. Smoking (hazard ratio [HR] = 5.066, p = 0.081), implant surface (HR = 18.776, p < 0.01), and timing of reimplantation (HR = 0.086, p < 0.01) were identified as risk factors influencing the refailure of second-time-placed implants. CONCLUSIONS: The survival rate of second-time-placed implants was lower than that of first-time-placed implants. The risk factors for second-time-placed implant failure were smoking, implant surface, and timing of reimplantation. To prevent further failure, previous failure factors should be analyzed and modifiable risk factors must be controlled before reimplantation.

Performance of Activities of Daily Living in Typically Developing Children in Korea: Normative Value of K-MBI.

OBJECTIVE: To determine the normative values of the Korean version of the Modified Barthel Index (K-MBI) score for typically developing children in Korea and assess its suitability for use in children. METHODS: Rehabilitation physicians and occupational therapists with children were invited through an online platform to participate in a survey assessing their children's performance of activity of daily living (ADL) using the K-MBI. The questionnaire encompassed queries on sociodemographic information of children and the assessment criteria outlined in the K-MBI. The standardized K-MBI scores by age were estimated using the nonlinear least squares method. RESULTS: The analysis incorporated responses from a total of 206 individuals. K-MBI total scores showed a rapid increase over the first 8 years of life, with 99% of children achieving a score of 90 or higher by age 8. Mobility scores exhibited a swift increase during early childhood, surpassing 90% of the maximum score at 3 years of age and nearing 100% at 7 years of age. In contrast, self-care scores demonstrated a more gradual advancement, achieving approximately 100% of the maximum score by the age of 10 years. CONCLUSION: Age-specific normative values for K-MBI scores of typically developing children were established, which can be used as a reference in clinical care. While the K-MBI captured the overall trajectory of children's ADL development, it did not discern subtle differences across various developmental stages. There is a need for the development of more refined assessment tools tailored specifically to children.

Unique inverse association between allergic rhinitis and periodontitis: a nationwide population-based study.

The increase in fine dust levels in the atmosphere has been associated with a growth in the incidence of environmental diseases, including allergic rhinitis (AR). Nasal obstruction caused by AR can impact the conditions in the oral cavity. The aim of this study was to determine the association between AR and periodontitis in the Republic of Korea. This study was based on data from the Seventh Korea National Health and Nutrition Examination Survey (KNHANES VII-1, 2016), which was conducted by the Korea Centers for Disease Control and Prevention. The study included 6129 adults older than 19 years. Sociodemographic information and medical variables including history of treatment of periodontitis (HTP) reflecting diagnosis of periodontitis and diagnosis of diseases such as AR were extracted from the data. HTP and AR were reported for 22.81 ± 0.84% (weighted percentage ± standard error) and 15.32 ± 0.63% of the studied population, respectively. A diagnosis of AR was reported for 11.07 ± 1.28% of those with HTP and for 17.55 ± 1.84% of those without HTP. From these, it was inferred that the prevalence of HTP was 1.536-fold higher in the non-AR group than in their counterparts with AR. Significant association was found between AR and HTP among those aged ≤ 64 years and the odds ratio (OR) of AR group for HTP was 0.62 (95% confidence interval:0.44-0.87; P = 0.0057). From this result, it can be inferred that patients diagnosed AR have lower risk of periodontitis.

Effect of photodynamic therapy according to differences in photosensitizers on Staphylococcus aureus biofilm on titanium.

PURPOSE: This study aimed to evaluate the antimicrobial effect of photodynamic therapy (PDT) against Staphylococcus aureus biofilm on a titanium surface and to compare the differences in the effect of PDT using toluidine blue O (TBO) and methylene blue (MB) as a photosensitizer. METHODS: The bacterial strain S. aureus ATCC 25,923 was used. Sandblasted and acid-etched (SLA) disks were divided into the following six groups: phosphate buffer saline (PBS), TBO, MB, PBS with laser (PBS + L), TBO with laser (TBO + L), and MB with laser (MB + L). The laser group samples were irradiated by a cold diode laser for 60 s. After treatment, the number of surviving bacteria was calculated by counting the colony-forming units (CFUs) and confocal laser scanning microscopy (CLSM) was applied to observe the bacteria on the disk surface. RESULTS: The TBO + L and MB + L groups showed significantly lower CFU/ml than the other groups (p < 0.01). The TBO + L group showed significantly lower CFU/ml than the MB + L group (p = 0.032). There was no significant difference between the PBS, TBO, MB, and PBS + L groups. Within the limitations of this in vitro study, PDT with TBO and MB can effectively reduce S. aureus biofilm on SLA titanium surfaces. TBO is more effective than MB as a photosensitizer. PDT with TBO may be applied to the treatment of peri­implant disease in the future.

Temporal changes of periodontal tissue pathology in a periodontitis animal model.

PURPOSE: This study aimed to characterize the early stages of periodontal disease and determine the optimal period for its evaluation in a mouse model. The association between the duration of ligation and its effect on the dentogingival area in mice was evaluated using micro-computed tomography (CT) and histological analysis. METHODS: Ninety mice were allocated to an untreated control group or a ligation group in which periodontitis was induced by a 6-0 silk ligation around the left second maxillary molar. Mice were sacrificed at 1, 2, 3, 4, 5, 8, 11, and 14 days after ligature placement. Alveolar bone destruction was evaluated using micro-CT. Histological analysis was performed to assess the immune-inflammatory processes in the periodontal tissue. RESULTS: No significant difference in alveolar bone loss was found compared to the control group until day 3 after ligature placement, and a gradual increase in alveolar bone loss was observed from 4 to 8 days following ligature placement. No significant between-group differences were observed after 8 days. The histological analysis demonstrated that the inflammatory response was evident from day 4. CONCLUSIONS: Our findings in a mouse model provide experimental evidence that ligature-induced periodontitis models offer a consistent progression of disease with marginal attachment down-growth, inflammatory infiltration, and alveolar bone loss.

Suboptimal Mitochondrial Activity Facilitates Nuclear Heat Shock Responses for Proteostasis and Genome Stability.

Thermal stress induces dynamic changes in nuclear proteins and relevant physiology as a part of the heat shock response (HSR). However, how the nuclear HSR is fine-tuned for cellular homeostasis remains elusive. Here, we show that mitochondrial activity plays an important role in nuclear proteostasis and genome stability through two distinct HSR pathways. Mitochondrial ribosomal protein (MRP) depletion enhanced the nucleolar granule formation of HSP70 and ubiquitin during HSR while facilitating the recovery of damaged nuclear proteins and impaired nucleocytoplasmic transport. Treatment of the mitochondrial proton gradient uncoupler masked MRP-depletion effects, implicating oxidative phosphorylation in these nuclear HSRs. On the other hand, MRP depletion and a reactive oxygen species (ROS) scavenger non-additively decreased mitochondrial ROS generation during HSR, thereby protecting the nuclear genome from DNA damage. These results suggest that suboptimal mitochondrial activity sustains nuclear homeostasis under cellular stress, providing plausible evidence for optimal endosymbiotic evolution via mitochondria-to-nuclear communication.