Characterization of the unique oral microbiome of children harboring Helicobacter pylori in the oral cavity

Objective

Helicobacter pylori infection is acquired in childhood via the oral cavity, although its relationship with the characteristics of the oral microbiome has not been elucidated. In this study, we performed comprehensive analysis of the oral microbiome in children and adults with or without H. pylori in the oral cavity.

Methods

Bacterial DNA was extracted from 41 adult and 21 child saliva specimens, and H. pylori was detected using PCR. 16S rRNA gene amplification was performed for next-generation sequencing. Bioinformatic analyses were conducted using Quantitative Insights into Microbial Ecology 2 (QIIME 2).

Results

Faith's phylogenetic diversity analysis showed a significant difference between H. pylori-negative adult and child specimens in terms of α-diversity (p < 0.05), while no significant difference was observed between H. pylori-positive adult and child specimens. There was also a significant difference in β-diversity between H. pylori-positive and negative child specimens (p < 0.05). Taxonomic analysis at the genus level revealed that Porphyromonas was the only bacterium that was significantly more abundant in both H. pylori-positive adults and children than in corresponding negative specimens (p < 0.01 and p < 0.05, respectively).

Conclusion

These results suggest unique oral microbiome characteristics in children with H. pylori infection in the oral cavity.

Transcriptomic analysis of Porphyromonas gingivalis-infected head and neck cancer cells: Identification of PLAU as a candidate prognostic biomarker

Periodontal disease is a risk factor for head and neck squamous cell carcinoma (HNSCC), and Porphyromonas gingivalis, a major periodontal pathogen, has been identified as a specific and potentially independent microbial factor that increases the risk of cancer mortality. Gene expression in HNSCC due to P. gingivalis infection and how changes in gene expression affect the prognosis of HNSCC patients are not clarified. When P. gingivalis was cultured with HNSCC cells, it efficiently adhered to these cells and enhanced their invasive ability. A transcriptome analysis of P. gingivalis -infected HNSCC cells showed that genes related to migration, including CCL20, CITED2, CTGF, C8orf44-SGK3, DUSP10, EGR3, FUZ, HBEGF, IL1B, IL24, JUN, PLAU, PTGS2, P2RY1, SEMA7A, SGK1 and SIX2, were highly up- or down-regulated. The expression of up-regulated genes was examined using the expression data of HNSCC patients obtained from The Cancer Genome Atlas (TCGA) database, and the expression of 5 genes, including PLAU, was found to be higher in cancer tissue than in solid normal tissue. An analysis of protein-protein interactions revealed that these 5 genes formed a dense network. A Cox regression analysis showed that high PLAU expression levels were associated with a poor prognosis in patients with TCGA-HNSCC. Furthermore, the prognostic impact correlated with tumour size and the presence or absence of lymph node metastasis. Collectively, these results suggest the potential of PLAU as a molecular prognostic marker in HNSCC patients. Further in vivo and in vitro studies are needed to verify the findings of this study.

Inhibitory Effects of Shikonin Dispersion, an Extract of Lithospermum erythrorhizon Encapsulated in β-1,3-1,6 Glucan, on Streptococcus mutans and Non-Mutans Streptococci

Shikonin is extracted from the roots of Lithospermum erythrorhizon, and shikonin extracts have been shown to have inhibitory effects on several bacteria. However, shikonin extracts are difficult to formulate because of their poor water solubility. In the present study, we prepared a shikonin dispersion, which was solubilized by the inclusion of β-1,3-1,6 glucan, and analysed the inhibitory effects of this dispersion on Streptococcus mutans and non-mutans streptococci. The shikonin dispersion showed pronounced anti-S. mutans activity, and inhibited growth of and biofilm formation by this bacterium. The shikonin dispersion also showed antimicrobial and antiproliferative effects against non-mutans streptococci. In addition, a clinical trial was conducted in which 20 subjects were asked to brush their teeth for 1 week using either shikonin dispersion-containing or non-containing toothpaste, respectively. The shikonin-containing toothpaste decreased the number of S. mutans in the oral cavity, while no such effect was observed after the use of the shikonin-free toothpaste. These results suggest that shikonin dispersion has an inhibitory effect on S. mutans and non-mutans streptococci, and toothpaste containing shikonin dispersion may be effective in preventing dental caries.

Potential Role of the Intratumoral Microbiota in Prognosis of Head and Neck Cancer

The tumor microbiome, a relatively new research field, affects tumor progression through several mechanisms. The Cancer Microbiome Atlas (TCMA) database was recently published. In the present study, we used TCMA and The Cancer Genome Atlas and examined microbiome profiling in head and neck squamous cell carcinoma (HNSCC), the role of the intratumoral microbiota in the prognosis of HNSCC patients, and differentially expressed genes in tumor cells in relation to specific bacterial infections. We investigated 18 microbes at the genus level that differed between solid normal tissue (n = 22) and primary tumors (n = 154). The tissue microbiome profiles of Actinomyces, Fusobacterium, and Rothia at the genus level differed between the solid normal tissue and primary tumors of HNSCC patients. When the prognosis of groups with rates over and under the median for each microbe at the genus level was examined, rates for Leptotrichia which were over the median correlated with significantly higher overall survival rates. We then extracted 35 differentially expressed genes between the over- and under-the-median-for-Leptotrichia groups based on the criteria of >1.5 fold and p < 0.05 in the Mann-Whitney U-test. A pathway analysis showed that these Leptotrichia-related genes were associated with the pathways of Alzheimer disease, neurodegeneration-multiple diseases, prion disease, MAPK signaling, and PI3K-Akt signaling, while protein-protein interaction analysis revealed that these genes formed a dense network. In conclusion, probiotics and specific antimicrobial therapy targeting Leptotrichia may have an impact on the prognosis of HNSCC.

Transfer learning in a biomaterial fibrosis model identifies in vivo senescence heterogeneity and contributions to vascularization and matrix production across species and diverse pathologies

Cellular senescence is a state of permanent growth arrest that plays an important role in wound healing, tissue fibrosis, and tumor suppression. Despite senescent cells' (SnCs) pathological role and therapeutic interest, their phenotype in vivo remains poorly defined. Here, we developed an in vivo-derived senescence signature (SenSig) using a foreign body response-driven fibrosis model in a p16-CreERT2;Ai14 reporter mouse. We identified pericytes and "cartilage-like" fibroblasts as senescent and defined cell type-specific senescence-associated secretory phenotypes (SASPs). Transfer learning and senescence scoring identified these two SnC populations along with endothelial and epithelial SnCs in new and publicly available murine and human data single-cell RNA sequencing (scRNAseq) datasets from diverse pathologies. Signaling analysis uncovered crosstalk between SnCs and myeloid cells via an IL34-CSF1R-TGFβR signaling axis, contributing to tissue balance of vascularization and matrix production. Overall, our study provides a senescence signature and a computational approach that may be broadly applied to identify SnC transcriptional profiles and SASP factors in wound healing, aging, and other pathologies.

Inhibitory Effect of Adsorption of Streptococcus mutans onto Scallop-Derived Hydroxyapatite

Hydroxyapatite adsorbs various substances, but little is known about the effects on oral bacteria of adsorption onto hydroxyapatite derived from scallop shells. In the present study, we analyzed the effects of adsorption of Streptococcus mutans onto scallop-derived hydroxyapatite. When scallop-derived hydroxyapatite was mixed with S. mutans, a high proportion of the bacterial cells adsorbed onto the hydroxyapatite in a time-dependent manner. An RNA sequencing analysis of S. mutans adsorbed onto hydroxyapatite showed that the upregulation of genes resulted in abnormalities in pathways involved in glycogen and histidine metabolism and biosynthesis compared with cells in the absence of hydroxyapatite. S. mutans adsorbed onto hydroxyapatite was not killed, but the growth of the bacteria was inhibited. Electron microscopy showed morphological changes in S. mutans cells adsorbed onto hydroxyapatite. Our results suggest that hydroxyapatite derived from scallop shells showed a high adsorption ability for S. mutans. This hydroxyapatite also caused changes in gene expression related to the metabolic and biosynthetic processes, including the glycogen and histidine of S. mutans, which may result in a morphological change in the surface layer and the inhibition of the growth of the bacteria.

Outline of Salivary Gland Pathogenesis of Sjögren's Syndrome and Current Therapeutic Approaches

Sjögren's syndrome (SS) is an autoimmune disease characterized by the involvement of exocrine glands such as the salivary and lacrimal glands. The minor salivary glands, from which tissue samples may be obtained, are important for the diagnosis, evaluation of therapeutic efficacy, and genetic analyses of SS. In the onset of SS, autoantigens derived from the salivary glands are recognized by antigen-presenting dendritic cells, leading to the activation of T and B cells, cytokine production, autoantibody production by plasma cells, the formation of ectopic germinal centers, and the destruction of salivary gland epithelial cells. A recent therapeutic approach with immune checkpoint inhibitors for malignant tumors enhances the anti-tumor activity of cytotoxic effector T cells, but also induces SS-like autoimmune disease as an adverse event. In the treatment of xerostomia, muscarinic agonists and salivary gland duct cleansing procedure, as well as sialendoscopy, are expected to ameliorate symptoms. Clinical trials on biological therapy to attenuate the hyperresponsiveness of B cells in SS patients with systemic organ involvement have progressed. The efficacy of treatment with mesenchymal stem cells and chimeric antigen receptor T cells for SS has also been investigated. In this review, we will provide an overview of the pathogenesis of salivary gland lesions and recent trends in therapeutic approaches for SS.

Hyperphosphorylated PTEN exerts oncogenic properties

PTEN is a multifaceted tumor suppressor that is highly sensitive to alterations in expression or function. The PTEN C-tail domain, which is rich in phosphorylation sites, has been implicated in PTEN stability, localization, catalytic activity, and protein interactions, but its role in tumorigenesis remains unclear. To address this, we utilized several mouse strains with nonlethal C-tail mutations. Mice homozygous for a deletion that includes S370, S380, T382 and T383 contain low PTEN levels and hyperactive AKT but are not tumor prone. Analysis of mice containing nonphosphorylatable or phosphomimetic versions of S380, a residue hyperphosphorylated in human gastric cancers, reveal that PTEN stability and ability to inhibit PI3K-AKT depends on dynamic phosphorylation-dephosphorylation of this residue. While phosphomimetic S380 drives neoplastic growth in prostate by promoting nuclear accumulation of β-catenin, nonphosphorylatable S380 is not tumorigenic. These data suggest that C-tail hyperphosphorylation creates oncogenic PTEN and is a potential target for anti-cancer therapy.

Sublingual Dermoid Cyst in Young Child

A dermoid cyst is a benign congenital lesion of ectodermal origin that can arise in any region of the body, though occurrence is rare. A young girl aged 2 years 4 months was referred to our hospital because of a painless mass in the floor of the mouth. Intraoral examination findings revealed a painless movable elastic soft mass on the floor of the mouth measuring approximately 15 mm in diameter. Magnetic resonance imaging indicated a cystic lesion, with low signal intensity shown in T1-weighted and extremely high signal intensity in T2-weighted images. These clinical findings indicated the presence of a dermoid cyst and removal was planned. Under general anesthesia with nasal intubation, surgical removal was performed through an incision on the floor of the mouth. Blunt dissection exposed the integrity of the cyst capsule, which was weakly attached to adjacent tissue. The excised mass was 19 mm × 14 mm × 11 mm in size. Histological examination findings confirmed a diagnosis of dermoid cyst. The operation was successfully completed without any complications and the postoperative course was good. It is important to properly evaluate cysts in children and provide proper treatment with appropriate timing.

Resistin gene expression: Novel study in dromedary camel (Camelus dromedarius)

Resistin, an adipocyte-specific hormone involved in insulin resistance and adipocyte differentiation, was initially identified in adipose tissue and macrophages. The physiological role of this molecule in camels remains largely unexplored. This study analysed for the first time blood and tissue levels of resistin as well as expression of resistin gene by real time PCR in adipose tissue (hump, visceral & epididymal) and different muscles (gastrocnemius, heart and caecum) in dromedary camels. The results revealed that resistin concentration was significantly (P<0.01) higher in epididymal adipose tissue as compared to other tissues and the lowest concentration was detected in serum. Additionally, the differential mRNA expression levels of resistin gene showed the highest expression level in epididymal adipose tissue as compared to other tissues. In conclusion, the results demonstrated for the first time that resistin was expressed in different tissues of dromedary camels. These data underscore an important facet of the physiological role of resistin as a factor involved in insulin resistance and glucose metabolism in camels.

A Case of X-Linked Hypophosphatemic Rickets with Dentin Dysplasia in Mandibular Third Molars

X-linked hypophosphatemic rickets (XLH) is a disease characterized by impaired bone mineralization, and its dental features include gingival abscesses and large pulp spaces due to dentin dysplasia. A 20-year-old woman with XLH was referred to oral surgery for extraction of mandibular third molars. She was diagnosed with XLH at approximately 1 year of age and was treated thereafter. There was no history of gingival abscesses, and panoramic radiographic and computed tomographic examinations revealed no evidence of dentin dysplasia. However, histopathological examination of the extracted teeth showed dentin dysplasia, including interglobular dentin. In this XLH patient, dentin dysplasia was revealed histologically even though no obvious abnormality was found on visual and radiographic examinations. These findings suggest that in patients with XLH, oral management must take dentin dysplasia of the permanent teeth into consideration even if the patient’s general condition is well controlled with conventional therapy.

Characterization of the unique oral microbiome of children with Down syndrome

Down syndrome creates an abnormal oral environment, including susceptibility to periodontal disease at a young age, but there are no detailed studies of the oral microbiome in children with Down syndrome. In this study, we performed a comprehensive analysis of the oral bacteria of 40 children with Down syndrome and 40 non-Down syndrome children. Microbial DNA was extracted from dental plaque specimens and the V4 hypervariable region of the bacterial 16S rRNA gene was analyzed using the MiSeq platform. There were significant differences between the Down syndrome and non-Down syndrome groups in mean numbers of operational taxonomic units, and α- and β-diversity (P < 0.05). Interestingly, significant differences in α- and β-diversity between the two groups were only observed in subjects with gingival inflammation, but not in those without gingival inflammation (P < 0.05). Taxonomic analysis at the genus or species levels showed significant differences in relative abundance levels of certain bacteria between the Down syndrome and non-Down syndrome groups, including Corynebacterium, Abiotrophia and Lautropia (P < 0.05). These results suggest that children with Down syndrome may have a unique oral microbiome that could impact the development of dental diseases common in people with the syndrome.

Oral Immune-Related Adverse Events Caused by Immune Checkpoint Inhibitors: Salivary Gland Dysfunction and Mucosal Diseases

Conventional chemotherapy and targeted therapies have limited efficacy against advanced head and neck squamous cell carcinoma (HNSCC). The immune checkpoint inhibitors (ICIs) such as antibodies against CTLA-4, PD-1, and PD-L1 interrupt the co-inhibitory pathway of T cells and enhance the ability of CD8+ T cells to destroy tumors. Even in advanced HNSCC patients with recurrent diseases and distant metastasis, ICI therapy shows efficiency and become an effective alternative to conventional chemotherapy. However, as this therapy releases the immune tolerance state, cytotoxic CD8+ T cells can also attack organs and tissues expressing self-antigens that cross-react with tumor antigens and induce immune-related adverse events (irAEs). When patients with HNSCC are treated with ICIs, autoimmune diseases occur in multiple organs including the skin, digestive tract, endocrine system, liver, and respiratory tract. Treatment of various malignancies, including HNSCC, with ICIs may result in the appearance of oral irAEs. In the oral cavity, an oral lichenoid reaction (OLR) and pemphigoid develop. Sicca syndrome also occurs in association with ICIs, affecting the salivary glands to induce xerostomia. It is necessary to elucidate the pathogenic mechanisms of these intractable diseases that are not seen with conventional therapy. Early diagnosis and appropriate approaches to irAEs are needed for efficient treatment of advanced HNSCC by ICIs.

Effect of Vitamin D supplementation in patients with liver cirrhosis having spontaneous bacterial peritonitis: a randomized controlled study

OBJECTIVE

Spontaneous Bacterial Peritonitis (SBP) is one of the most serious liver cirrhosis with ascites complications. Vitamin D (Vit D) deficiency has been associated with a high risk of infection and mortality in cirrhotic patients. Herein, the assessment of Vit D level as a prognostic marker in SBP patients and the impact of Vit D supplementation on their treatment plan was studied as well.

PATIENTS AND METHODS

Ascetic patients with SBP and Vit D deficiency were divided randomly into treatment and control groups. The control group received standard treatment without Vit D and the treatment group received standard treatment plus Vit D. Clinical monitoring of Vit D was done over 6 months.

RESULTS

At baseline, all patients in both groups revealed an elevated serum and ascetic TLC, AST, ALT, total and direct bilirubin, in addition to elevation in INR and procalcitonin (PCT) level. Univariate regression analysis confirmed that deficiency of Vit D was an independent predictor of infection and mortality (p < 0.01; Crude Hazard Ratio: 0.951). Over 6 months, the study revealed significant improvement in serum Vit D level in the treatment group (34.6 ± 9.2 and 18.3 ± 10.0 ng/mL; p < 0.001). Moreover, a statistically significant increase in survival rate (64% vs. 42%; p < 0.05) and duration (199.5 days vs. 185.5 days; p < 0.05) were recorded as well. Univariate and multivariate regression analysis confirmed that Vit D supplementation was positively correlated to survival over 6 months (p < 0.001; Adjusted Hazard Ratio: 0.895).

CONCLUSIONS

Vit D deficiency is prevalent in SBP cirrhotic patients and is used as an independent predictor of infection and death. Therefore, Vit D supplementation revealed improvement in their response to treatment.

p21 produces a bioactive secretome that places stressed cells under immunosurveillance

Immune cells identify and destroy damaged cells to prevent them from causing cancer or other pathologies by mechanisms that remain poorly understood. Here, we report that the cell-cycle inhibitor p21 places cells under immunosurveillance to establish a biological timer mechanism that controls cell fate. p21 activates retinoblastoma protein (Rb)–dependent transcription at select gene promoters to generate a complex bioactive secretome, termed p21-activated secretory phenotype (PASP). The PASP includes the chemokine CXCL14, which promptly attracts macrophages. These macrophages disengage if cells normalize p21 within 4 days, but if p21 induction persists, they polarize toward an M1 phenotype and lymphocytes mount a cytotoxic T cell response to eliminate target cells, including preneoplastic cells. Thus, p21 concurrently induces proliferative arrest and immunosurveillance of cells under duress.

Potential involvement of Streptococcus mutans possessing collagen binding protein Cnm in infective endocarditis

Streptococcus mutans, a significant contributor to dental caries, is occasionally isolated from the blood of patients with infective endocarditis. We previously showed that S. mutans strains expressing collagen-binding protein (Cnm) are present in the oral cavity of approximately 10-20% of humans and that they can effectively invade human umbilical vein endothelial cells (HUVECs). Here, we investigated the potential molecular mechanisms of HUVEC invasion by Cnm-positive S. mutans. The ability of Cnm-positive S. mutans to invade HUVECs was significantly increased by the presence of serum, purified type IV collagen, and fibrinogen (p < 0.001). Microarray analyses of HUVECs infected by Cnm-positive or -negative S. mutans strains identified several transcripts that were differentially upregulated during invasion, including those encoding the small G protein regulatory proteins ARHGEF38 and ARHGAP9. Upregulation of these proteins occurred during invasion only in the presence of serum. Knockdown of ARHGEF38 strongly reduced HUVEC invasion by Cnm-positive S. mutans. In a rat model of infective endocarditis, cardiac endothelial cell damage was more prominent following infection with a Cnm-positive strain compared with a Cnm-negative strain. These results suggest that the type IV collagen-Cnm-ARHGEF38 pathway may play a crucial role in the pathogenesis of infective endocarditis.

Potential involvement of Helicobacter pylori from oral specimens in overweight body-mass index

The bacterium Helicobacter pylori was originally classified in the Campylobacter genus, which contains major periodontopathic bacterial species, and H. pylori DNA has been found in the oral cavity. Although many studies show an association between the presence of periodontal bacteria and an overweight body-mass index (BMI; >25 kg/m²), the relationship between body weight and the presence of H. pylori in the oral cavity has not been demonstrated. Herein, we analysed the relationship between H. pylori in the oral cavity and systemic conditions, including the overweight BMI. Saliva specimens and extracted teeth were obtained from 87 subjects; the distribution of H. pylori among these specimens was analysed with the polymerase chain reaction. Subjects with an overweight BMI exhibited significantly higher detection rates of H. pylori in saliva, compared with non-overweight subjects (BMI <25 kg/m²) (P < 0.05). A clinical history of digestive diseases was not associated with the presence of H. pylori in overweight subjects, whereas subjects with both severe dental caries and an overweight BMI showed a higher detection rate of H. pylori in saliva specimens, compared with other groups. These results suggest that the detection of H. pylori in the oral cavity could be associated with the overweight BMI, which was predominant among subjects with severe dental caries.

Piezosurgery for Intraosseous Venous Malformation of the Mandible

Intraosseous venous malformation of the mandible is rare. A 59-year-old woman was referred to our hospital for evaluation of a radiolucent lesion in the left body of the mandible that had been detected on a routine radiologic dental checkup. The patient wished for follow-up rather than operation. After 2 years’ follow-up, the radiolucent lesion had slowly grown, and the patient decided to have an operation. The lesion was removed surgically using the piezosurgery system, and conservation of the inferior alveolar nerve was achieved under general anesthesia. After operation, she reported an initial change in sensation (paresthesia). The sensitivity was recovered after 6 months. Patient prognosis has been good to date, with no symptoms indicating recurrence. We used to treat intraosseous venous malformations using the piezosurgery system. The present report describes a patient with intraosseous venous malformation of the mandible by complete excision and conservation of the nerve. It was useful to use piezosurgery for conservation of inferior alveolar nerve.

Mosaic-variegated aneuploidy syndrome mutation or haploinsufficiency in Cep57 impairs tumor suppression

A homozygous truncating frameshift mutation in CEP57 (CEP57T/T) has been identified in a subset of mosaic-variegated aneuploidy (MVA) patients; however, the physiological roles of the centrosome-associated protein CEP57 that contribute to disease are unknown. To investigate these, we have generated a mouse model mimicking this disease mutation. Cep57T/T mice died within 24 hours after birth with short, curly tails and severely impaired vertebral ossification. Osteoblasts in lumbosacral vertebrae of Cep57T/T mice were deficient for Fgf2, a Cep57 binding partner implicated in diverse biological processes, including bone formation. Furthermore, a broad spectrum of tissues of Cep57T/T mice had severe aneuploidy at birth, consistent with the MVA patient phenotype. Cep57T/T mouse embryonic fibroblasts and patient-derived skin fibroblasts failed to undergo centrosome maturation in G2 phase, causing premature centriole disjunction, centrosome amplification, aberrant spindle formation, and high rates of chromosome missegregation. Mice heterozygous for the truncating frameshift mutation or a Cep57-null allele were overtly indistinguishable from WT mice despite reduced Cep57 protein levels, yet prone to aneuploidization and cancer, with tumors lacking evidence for loss of heterozygosity. This study identifies Cep57 as a haploinsufficient tumor suppressor with biologically diverse roles in centrosome maturation and Fgf2-mediated bone formation.

Proteomic Analysis of Secretomes of Oncolytic Herpes Simplex Virus-Infected Squamous Cell Carcinoma Cells

Oncolytic herpes simplex virus type 1 (HSV-1) strain RH2 induced immunogenic cell death (ICD) with the release and surface exposure of damage-associated molecular patterns (DAMPs) in squamous cell carcinoma (SCC) SCCVII cells. The supernatants of RH2-infected SCCVII cells also exhibited antitumor ability by intratumoral administration in SCCVII tumor-bearing mice. The supernatants of RH2-infected cells and mock-infected cells were concentrated to produce Med24 and MedC for proteomic analyses. In Med24, the up- and down-regulated proteins were observed. Proteins including filamin, tubulin, t-complex protein 1 (TCP-1), and heat shock proteins (HSPs), were up-regulated, while extracellular matrix (ECM) proteins were markedly down-regulated. Viral proteins were detected in Med 24. These results indicate that HSV-1 RH2 infection increases the release of danger signal proteins and viral gene products, but decreases the release of ECM components. These changes may alter the tumor microenvironment (TME) and contribute to enhancement of anti-tumor immunity against SCC.

Cyclin A2 is an RNA binding protein that controls Mre11 mRNA translation

Cyclin A2 activates the cyclin-dependent kinases Cdk1 and Cdk2 and is expressed at elevated levels from S phase until early mitosis. We found that mutant mice that cannot elevate cyclin A2 are chromosomally unstable and tumor-prone. Underlying the chromosomal instability is a failure to up-regulate the meiotic recombination 11 (Mre11) nuclease in S phase, which leads to impaired resolution of stalled replication forks, insufficient repair of double-stranded DNA breaks, and improper segregation of sister chromosomes. Unexpectedly, cyclin A2 controlled Mre11 abundance through a C-terminal RNA binding domain that selectively and directly binds Mre11 transcripts to mediate polysome loading and translation. These data reveal cyclin A2 as a mechanistically diverse regulator of DNA replication combining multifaceted kinase-dependent functions with a kinase-independent, RNA binding-dependent role that ensures adequate repair of common replication errors.

Incident fracture associated with increased risk of mortality even after adjusting for frailty status in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Cohort Study

Frail elderly individuals have elevated risks of both fracture and mortality. We found that incident fractures were associated with an increased risk of death even after adjusting for pre-fracture frailty status as represented by physical performance tests and laboratory tests for common geriatric diseases in community-dwelling elderly Japanese men.

INTRODUCTION

While fractures reportedly increase the risk of mortality, frailty may complicate this association, generating a false-positive result. We evaluated this association after adjusting for pre-fracture levels of frailty.

METHODS

We examined 1998 community-dwelling ambulatory men aged ≥65 years at baseline in the Fujiwara-kyo Osteoporosis Risk in Men Study for frailty status as represented by activities of daily living (ADL), physical performance tests (grip strength, one-foot standing balance with eyes open, timed 10-m walk), and laboratory sera tests. Participants were then followed for 5 years for incident clinical fractures and death. Effects of incident fracture on death were determined by Cox proportional hazards model with the first fracture during follow-up as a time-dependent predictor and with frailty status indices as covariates.

RESULTS

We identified 111 fractures in 99 men and 138 deaths during the follow-up period (median follow-up, 4.5 years). Participants with incident fractures did not have significantly worse frailty statuses, but did show a significantly higher cumulative mortality rate than those without fractures (p = 0.0047). Age-adjusted hazard ratio (HR) of death for incident fracture was 3.57 (95 % confidence interval: 2.05, 6.24). When adjusted for physical performance, this decreased to 2.77 (1.51, 5.06), but remained significant. The HR showed no significant change when adjusted for laboratory test results (3.96 (2.26, 6.94)). Exclusion of deaths within the first 24 months of follow-up did not alter these results.

CONCLUSION

Incident clinical fracture was associated with an elevated risk of death independently of pre-fracture levels of frailty in community-dwelling elderly men.

Autophagy as a Survival Mechanism for Squamous Cell Carcinoma Cells in Endonuclease G-Mediated Apoptosis

Safingol, L- threo-dihydrosphingosine, induces cell death in human oral squamous cell carcinoma (SCC) cells through an endonuclease G (endoG) -mediated pathway. We herein determined whether safingol induced apoptosis and autophagy in oral SCC cells. Safingol induced apoptotic cell death in oral SCC cells in a dose-dependent manner. In safingol-treated cells, microtubule-associated protein 1 light chain 3 (LC3)-I was changed to LC3-II and the cytoplasmic expression of LC3, amount of acidic vesicular organelles (AVOs) stained by acridine orange and autophagic vacuoles were increased, indicating the occurrence of autophagy. An inhibitor of autophagy, 3-methyladenine (3-MA), enhanced the suppressive effects of safingol on cell viability, and this was accompanied by an increase in the number of apoptotic cells and extent of nuclear fragmentation. The nuclear translocation of endoG was minimal at a low concentration of safingol, but markedly increased when combined with 3-MA. The suppressive effects of safingol and 3-MA on cell viability were reduced in endoG siRNA- transfected cells. The scavenging of reactive oxygen species (ROS) prevented cell death induced by the combinational treatment, whereas a pretreatment with a pan-caspase inhibitor z-VAD-fmk did not. These results indicated that safingol induced apoptosis and autophagy in SCC cells and that the suppression of autophagy by 3-MA enhanced apoptosis. Autophagy supports cell survival, but not cell death in the SCC cell system in which apoptosis occurs in an endoG-mediated manner.