Liver sinusoidal endothelial cells (LSECs) are involved in the transport of nutrients, lipids, and lipoproteins, and LSEC injury occurs in various liver diseases including nonalcoholic fatty liver disease (NAFLD). However, the association between LSEC injury and NAFLD progression remains elusive. Accordingly, in this study, we aimed to elucidate the precise role of LSEC in the pathophysiology of NAFLD using two different mouse models, namely the choline-deficient, L-amino acid-defined and high-fat diet models. Administration of these diets resulted in liver metabolic dysregulation mimicking human NAFLD, such as steatosis, ballooning, lobular inflammation, and fibrosis, as well as central obesity, insulin resistance, and hyperlipidemia. LSEC injury appeared during the simple steatosis phase, and preceded the appearance of activated Kupffer cells and hepatic stellate cells (HSCs). These results indicate that LSEC injury may have a 'gatekeeper' role in the progression from simple steatosis to the early nonalcoholic steatohepatitis (NASH) stage, and LSEC injury may be necessary for the activation of Kupffer cells and HSCs, which in turn results in the development and perpetuation of chronic liver injuries. Taken together, our data provide new insights into the role of LSEC injury in NAFLD/NASH pathogenesis.

Extracellular histones are a damage-associated molecular pattern (DAMP) involved in the pathogenesis of various diseases. The mechanisms of histone-mediated injury in certain organs have been extensively studied, but an understanding of the pathophysiological role of histone-mediated injury in multiple organ injury remains elusive. To elucidate this role, we systemically subjected C57BL/6 mice to various doses of histones and performed a chronological evaluation of the morphological and functional changes in the lungs, liver, and kidneys. Notably, histone administration ultimately led to death after a dose-dependent aggravation of multiple organ injury. In chronological studies, pulmonary and hepatic injuries occurred within 15 minutes, whereas renal injuries presented at a later phase, suggesting that susceptibility to extracellular histones varies among organs. Histones bound to pulmonary and hepatic endothelial cells immediately after administration, leading to endothelial damage, which could be ameliorated by pretreatment with heparin. Furthermore, release of another DAMP, high-mobility group protein box 1, followed the histone-induced tissue damage, and an antibody against the molecule ameliorated hepatic and renal failure in a late phase. These findings indicate that extracellular histones induce multiple organ injury in two progressive stages-direct injury to endothelial cells and the subsequent release of other DAMPs-and that combination therapies against extracellular histones and high-mobility group protein box 1 may be a promising strategy for treating multiple organ injury.

Mitochondria from malignant tumor cell lines show a higher capability for hexokinase binding than those from normal liver. To explore possible differences in hexokinase binding sites of mitochondria between tumor cells and normal liver, we characterized porin isoforms expressed in tumor cells. Cloning experiments on the three porin isoforms, VDAC1, VDAC2 and VDAC3 from malignant tumor cell line AH130 clearly showed that their primary structures were completely identical to those of the corresponding VDACs of normal liver cells. Possible expression of the fourth porin isoform in AH130 cells was excluded by degenerate primer-based RT-PCR. However, the transcript levels of the three VDAC isoforms in AH130 cells were significantly higher than those in normal liver. These results suggest that the high hexokinase-binding capability of malignant tumor cell mitochondria was not due to any structural difference, but due to a quantitative difference in binding sites.

To examine whether valinomycin induces a mitochondrial permeability transition (PT), we investigated its effects on mitochondrial functions under various conditions. The acceleration of mitochondrial respiration and swelling, induced by valinomycin, were found to be insensitive to inhibitors of the ordinary PT, indicating that valinomycin does not induce the ordinary PT. Results of experiments using mitochondria isolated from transgenic mice expressing human bcl-2 also supported this conclusion. Furthermore, evidence for induction of PT pores by valinomycin was not obtained by either electron microscopic analysis of mitochondrial configurations or by measurement of the permeability of the inner mitochondrial membrane by use of polyethylene glycol. However, valinomycin did induce a significant release of cytochrome c, and thus it may be a nice tool to study the processes of mitochondrial cytochrome c release.

A density distribution of the interface states in GaAs Schottky barrier was derived for the first time from observed nonideal I-V characteristics of a GaAs Schottky barrier with an oxidized interface. With increasing forward bias voltage, the ideality factor increases and then decreases after passing a maximum. Fermi level of the interface states shifts with the applied bias in the interfacial layer model adopted for the analysis. The obtained energy level of the interface states is in agreement with a previously reported value. However, the absolute magnitude of the state density is quite small compared with that obtained from the weak dependence of the barrier height on metal work functions. Implications of this result are discussed.