The ubiquitination of mitochondrial proteins labels damaged mitochondria for degradation through mitophagy. We recently developed an in vivo system in which mitophagy is slowed by inhibiting mitochondrial division through knockout of Dnm1l/Drp1, a dynamin related GTPase that mediates mitochondrial division. Using this system, we revealed that the ubiquitination of mitochondrial proteins required SQSTM1/p62, but not the ubiquitin E3 ligase PRKN/parkin, during mitophagy. Here, we tested the role of PINK1, a mitochondrial protein kinase that activates mitophagy by phosphorylating ubiquitin, in mitochondrial ubiquitination by knocking out Pink1 in dnm1l-knockout liver. We found mitochondrial ubiquitination did not decrease in the absence of PINK1; instead, PINK1 was required for the degradation of MFN1 (mitofusin 1) and MFN2, two homologous outer membrane proteins that mediate mitochondrial fusion in dnm1l-knockout hepatocytes. These data suggest that mitochondrial ubiquitination is promoted by SQSTM1 independently of PINK1 and PRKN during mitophagy. PINK1 and PRKN appear to control the balance between mitochondrial division and fusion in vivo. Abbreviations: DNM1L/DRP1: dynamin 1-like; KEAP1: kelch-like ECH-associated protein 1; KO: knockout; MAP1LC3/LC3: microtubule-associated protein 1 light chain 3; MFN1/2: mitofusin 1/2; OPA1: OPA1, mitochondrial dynamin like GTPase; PDH: pyruvate dehydrogenase E1; PINK1: PTEN induced putative kinase 1; PRKN/parkin: parkin RBR E3 ubiquitin protein ligase.

Recently, medical rapid prototyping (MRP) models, fabricated with computer-aided design and computer-aided manufacture (CAD/CAM) techniques, have been applied to reconstructive surgery in the treatment of head and neck cancers. Here, we tested the use of preoperatively manufactured reconstruction plates, which were produced using MRP models. The clinical efficacy and esthetic outcome of using these products in mandibular reconstruction was evaluated. A series of 28 patients with malignant oral tumors underwent unilateral segmental resection of the mandible and simultaneous mandibular reconstruction. Twelve patients were treated with prebent reconstruction plates that were molded to MRP mandibular models designed with CAD/CAM techniques and fabricated on a combined powder bed and inkjet head three-dimensional printer. The remaining 16 patients were treated using conventional reconstruction methods. The surgical and esthetic outcomes of the two groups were compared by imaging analysis using post-operative panoramic tomography. The mandibular symmetry in patients receiving the MRP-model-based prebent plates was significantly better than that in patients receiving conventional reconstructive surgery. Patients with head and neck cancer undergoing reconstructive surgery using a prebent reconstruction plate fabricated according to an MRP mandibular model showed improved mandibular contour compared to patients undergoing conventional mandibular reconstruction. Thus, use of this new technology for mandibular reconstruction results in an improved esthetic outcome with the potential for improved quality of life for patients.

Heme oxygenase-1 (HO-1) is known as a stress-inducible protein. The present study was designed to investigate the relationship between HO-1 expression levels and clinical features of tongue cancer by using HO-1 responsiveness to stress as a clinical indicator. One-hundred and twelve biopsy samples from tongue squamous cell carcinomas were analyzed semiquantitatively by immunohistochemistry. Correlations between the expression level of HO-1 and the clinical features of tumors were statistically analyzed. Fifty-four cases with surgical confirmation of lymph node metastasis were examined for the association between cervical lymph node metastasis (pN) and other clinical features, including the HO-1 expression level, using logistic regression. The low HO-1 expression group contained significantly more undifferentiated samples (P=0.04) and pN positive cases (P=0.01) by univariate analysis. The low HO-1 expression group (odds ratio=8.49; 95% confidence interval=1.64-44.09, P=0.01) and an endophytic shape (odds ratio=16.79; 95% confidence interval=1.77-159.53, P=0.01) were significantly associated with an increased risk of developing lymph node metastasis by multivariate analysis. Low HO-1 expression was associated with lymph node metastasis. The expression profile suggests HO-1 could be used clinically as a marker for tumors possessing the potential for lymph node metastasis. This method could prove useful as an adjuvant method to detect lymph node metastasis and may help reduce the number of surgeries by indicating when surgery is unnecessary.

Calcium/calmodulin-dependent serine protein kinase (CASK) is a membrane-associated guanylate kinase (MAGUK) protein that is associated with neurodevelopmental disorders. CASK is thought to have both pre- and postsynaptic functions, but the mechanism and consequences of its functions in the brain have yet to be elucidated, because homozygous CASK-knockout (CASK-KO) mice die before brain maturation. Taking advantage of the X-chromosome inactivation (XCI) mechanism, here we examined the synaptic functions of CASK-KO neurons in acute brain slices of heterozygous CASK-KO female mice. We also analyzed CASK-knockdown (KD) neurons in acute brain slices generated by in utero electroporation. Both CASK-KO and CASK-KD neurons showed a disruption of the excitatory and inhibitory (E/I) balance. We further found that the expression level of the N-methyl-d-aspartate receptor subunit GluN2B was decreased in CASK-KD neurons and that overexpressing GluN2B rescued the disrupted E/I balance in CASK-KD neurons. These results suggest that the down-regulation of GluN2B may be involved in the mechanism of the disruption of synaptic E/I balance in CASK-deficient neurons.

Background and purpose: Periodontal disease is closely related to lifestyle-related diseases and obesity. It is widely known that moderate exercise habits lead to improvement in lifestyle-related diseases and obesity. However, little research has been undertaken into how exercise habits affect periodontal disease. The purpose of this study was to examine the effect of exercise habits on periodontal diseases and metabolic pathology. Methods: We conducted a prospective intervention research for 12 weeks. The subjects were 71 obese men who participated in an exercise and/or dietary intervention program. Fifty subjects were assigned to exercise interventions (exercise intervention group) and 21 subjects were assigned to dietary interventions (dietary intervention group). This research was conducted before and after each intervention program. Results: In the exercise intervention group, the number of teeth with a probing pocket depth (PPD) ≥4 mm significantly decreased from 14.4% to 5.6% (P<0.001), and the number of teeth with bleeding on probing (BOP) significantly decreased from 39.8% to 14.4% (P<0.001). The copy counts of Tannerella forsythia and Treponema denticola decreased significantly (P=0.001). A positive correlation was found between the change in the copy count of T. denticola and the number of teeth with PPD ≥4 mm (P=0.003) and the number of teeth with BOP (P=0.010). A positive correlation was also found between the change in the copy count of T. denticola and body weight (P=0.008), low-density lipoprotein cholesterol (P=0.049), and fasting insulin (P=0.041). However, in the dietary intervention group the copy count of T. denticola decreased significantly (P=0.007) and there was no correlation between the number of periodontal disease-causing bacteria and PPD and BOP. Conclusion: Our results are the first to show that exercise might contribute to improvements in periodontal disease.

Peroxiredoxin (Prx) I is an antioxidant protein expressed in proliferating cells. We investigated Prx I as marker for tongue cancer status by correlating clinical features with Prx I expression. Samples from 132 patients with squamous cell carcinoma in the tongue were examined by immunohistochemistry with an anti-Prx I antibody. Correlations between Prx I expression and the clinical features of tumors were statistically determined using univariate and multivariate analyses. Univariate analysis showed Prx I was significantly associated with local recurrence (P=0.033). By multiple logistic regression analysis, Prx I expression was associated with local recurrence (odds ratio: 2.84; 95% confidence interval: 1.09–7.43; P=0.034) and lymph node recurrence (odds ratio: 2.86; 95% confidence interval: 1.02–8.01; P=0.046). Our results suggested that Prx I expression indicates tumors with a high potential for recurrence. Prx I may be used clinically to guide treatment for squamous cell carcinoma of the tongue.