Polyethyleneimine renders mitochondrial membranes permeable by interacting with negatively charged phospholipids in them.

Polyethyleneimines (PEIs) are used for transfection of cells with nucleic acids. Meanwhile, the interaction of PEI with mitochondria causes cytochrome c release prior to apoptosis; the mechanisms how PEI causes this permeabilization of mitochondrial membranes and the release of cytochrome c remain unclear. To clarify these mechanisms, we examined the effects of branched-type PEI and linear-type PEI, each of which was 25 kDa in size, on mitochondria. The permeabilization potency of mitochondrial membranes by branched PEI was stronger than that by linear PEI. The permeabilization by PEIs were insensitive to permeability-transition inhibitors, indicating that PEI-induced permeabilization was not attributed to permeability transition. Meanwhile, PEIs caused permeabilization of artificial lipid vesicles; again, the permeabilization potency of branched PEI was stronger than that of linear PEI. Such a difference in this potency was close to that in the case of isolated mitochondria, signifying that the PEI-induced permeabilization of mitochondrial membranes could be attributed to PEI's interaction with the phospholipid phase. Furthermore, this PEI-induced permeabilization of the lipid vesicles was observed only in the case of lipid vesicles including negatively charged phospholipids. These results indicate that PEIs interacted with negatively charged phospholipids in the mitochondrial membranes to directly lead to their permeabilization.

Human odontogenic epithelial cells derived from epithelial rests of Malassez possess stem cell properties.

Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of the Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. ERM cells are unique epithelial cells that remain in periodontal tissues throughout adult life. They have a functional role in the repair/regeneration of cement or enamel. Here, we isolated odontogenic epithelial cells from ERM in the periodontal ligament, and the cells were spontaneously immortalized. Immortalized odontogenic epithelial (iOdE) cells had the ability to form spheroids and expressed stem cell-related genes. Interestingly, iOdE cells underwent osteogenic differentiation, as demonstrated by the mineralization activity in vitro in mineralization-inducing media and formation of calcification foci in iOdE cells transplanted into immunocompromised mice. These findings suggest that a cell population with features similar to stem cells exists in ERM and that this cell population has a differentiation capacity for producing calcifications in a particular microenvironment. In summary, iOdE cells will provide a convenient cell source for tissue engineering and experimental models to investigate tooth growth, differentiation, and tumorigenesis.

Establishment and characterization of a clear cell odontogenic carcinoma cell line with EWSR1-ATF1 fusion gene.

OBJECTIVE: Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumor (MOT) characterized by sheets and lobules of vacuolated and clear cells. To understand the biology of CCOC, we established a new cell line, CCOC-T, with EWSR1-ATF1 fusion gene from a mandible tumor with distant metastasis and characterized this cell line. MATERIALS AND METHODS: To detect the EWSR1-ATF1 fusion gene, we used three CCOC cases, including the present case, by RT-PCR and FISH analysis. We characterized established CCOC-T cells by checking cell growth, invasion and the expression of odontogenic factors and bone-related factors. Moreover, the gene expression profile of CCOC-T cells was examined by microarray analysis. RESULTS: Histologically, the primary tumor was comprised of cords and nests containing clear and squamoid cells separated by fibrous septa. In addition, ameloblastomatous islands with palisaded peripheral cells were observed, indicating probable odontogenic origin. This tumor expressed the fusion gene EWSR1-ATF1, which underlies the etiology of hyalinizing clear cell carcinoma (HCCC) and potentially that of CCOC. We found a breakpoint in the EWSR1-ATF1 fusion to be the same as that reported in HCCC. Established CCOC-T cells grew extremely slowly, but the cells showed highly invasive activity. Moreover, CCOC-T cells expressed bone-related molecules, odontogenic factors, and epithelial mesenchymal transition (EMT)-related molecules. CONCLUSION: To the best of our knowledge, this is the first report on the establishment of a CCOC cell line. CCOC-T cells serve as a useful in vitro model for understanding the pathogenesis and nature of MOT.

Neuroendocrine tumor in the mandible: a case report with imaging and histopathologic findings.

Neuroendocrine tumors (NETs) arise from neuroendocrine cells and are mostly observed in the gastrointestinal tract, pancreas, and lungs. NETs in the oral and maxillofacial region are extremely rare. We report a case of a 59-year-old woman with an NET in the mandible. The patient did not show any symptoms except for remarkable swelling and bleeding. The lesion appeared as a radiolucent honeycomb abnormality with bone destruction on panoramic radiography. The histopathologic diagnosis following a biopsy was NET. Contrast-enhanced computed tomography (CT), 18F-fluorodeoxyglucose positron emission computed tomography (18F-FDG PET/CT), and adrenal scintigraphy-labeled meta-iodobenylguanidine were the modalities added to identify the primary site. Multiple lesions were confirmed in the gastrointestinal tract. Endoscopy was performed to identify the lesions, and several lesions were observed protruding from the mucous membranes. However, the endoscopy specimens did not yield an accurate diagnosis because adequate samples were not acquired. Blood and urine tests revealed no functional activity caused by the tumors. Although the origin was not histopathologically confirmed with endoscopy, this patient was situationally diagnosed with nonfunctional NET originating from the duodenum, as demonstrated by the metastases in the mandible.

Involvement of protein kinase Cdelta in induction of apoptosis by cationic liposomes in macrophage-like RAW264.7 cells.

We have recently demonstrated that reactive oxygen species (ROS) play an important role in RAW264.7 cell apoptosis induced by cationic liposomes composed of stearylamine (SA-liposomes). In this study, we investigated whether protein kinase Cdelta PKCdelta) is involved in apoptosis induced by cationic liposomes. Tyrosine phosphorylation, nuclear localization, and cleavage of PKCdelta were observed following the treatment of cells with SA-liposomes, suggesting that SA-liposomes activate PKCdelta. Rottlerin, a specific inhibitor of PKCdelta, inhibited ROS generation and also suppressed apoptosis. Cell surface proteoglycans may contribute to PKCdelta activation by SA-liposomes. These findings suggest that PKCdelta is strongly associated with apoptosis induced by SA-liposomes.

Incidence, severity and factors related to drug-induced keratoepitheliopathy with glaucoma medications.

PURPOSE: To evaluate the incidence, severity, and factors related to drug-induced keratoepitheliopathy in eyes using antiglaucoma eye drops. PATIENTS AND METHODS: In a cross-sectional study, 749 eyes from 427 patients who had used one or more antiglaucoma eye drops were examined at Niigata University Medical and Dental Hospital or related facilities. The incidence and severity of superficial punctate keratitis (SPK), patient gender and age, type of glaucoma, and type of eye drops were recorded. SPK was graded according to the AD (A, area; D, density) classification. The severity score (SS) was calculated from A x D. RESULTS: SPK was observed in 382 (51.0%) of 749 eyes that had received any type of antiglaucoma eye drops. While 254 eyes (33.9%) were classified as A1D1 (SS 1), 34 eyes (4.6%) had severe SPK with SS 4 or more. The number of eye drops and the total dosing frequency per day were significantly greater in SPK-positive eyes than in eyes without SPK. The number of eye drops was proportional to the frequency and severity of SPK. Among eyes that were treated with three or more eye drops, SPK was more severe and more frequent in older patients (>/=71 years). In addition, a considerable difference was detected for each type of glaucoma. CONCLUSION: Drug-induced keratoepitheliopathy is often observed in eyes that have received recent antiglaucoma eye drops. The number of eye drops, the total dose frequency per day, patient age, and type of glaucoma may affect this condition. We have to consider not only the effects on intraocular pressure but also the incidence and severity of drug-induced keratoepitheliopathy as a frequent side effect of glaucoma medications.