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Various epidemiological studies suggest that alcohol intake is one of the risk factors leading to type II or non-insulin-dependent diabetes mellitus (NIDDM), but the effect of alcohol on β-cell function remains unexplored. To study the mechanism of the diabetogenic action of ethanol, we investigated the effect of ethanol on β-cell functions using a single clonal β-cell line, HIT-T15 cells. When HIT cells were treated with ethanol, the metabolic activity judged by MTT assay was inhibited in dose- and time dependent manners, but cytotoxicity was not observed. Ethanol also inhibited basal insulin secretion by 30% compared to the untreated control. However, glucose-stimulated insulin secretion was not impaired by ethanol although the basal insulin secretion was inhibited. These results imply that ethanol exert β-cells to overwork in order to compensate inhibition of the basal secretion. This finding may at least in part explain the diabetogenic action of ethanol. [Copyright &y& Elsevier]

• Low-dose bortezomib reduces the MHC class II expression on dendritic cells. • Low-dose bortezomib and rapamycin combination prolongs islet graft survival. • Low-dose bortezomib and rapamycin combination reduces Ag-specific IFN-γ + T cells. • Low-dose bortezomib and rapamycin combination increases FoxP3+ regulatory T cells. As the first FDA-approved proteasome inhibitor drug, bortezomib has been used for the treatment of multiple myeloma and lymphoma. However, its effects alone or in combination with other immunosuppressants on allogeneic islet transplantation have not been reported so far. In this study, we showed that the short-term combination treatment of low-dose bortezomib and rapamycin significantly prolonged the survival of islet allografts. Short-term treatment of low-dose (0.05 mg/kg or 0.1 mg/kg) bortezomib reduced the MHC class II expression in dendritic cells (DCs) of alloantigen-sensitized mice, and prolonged the islet allograft survival for up to 50 days in diabetic mice. Notably, when bortezomib was combined with rapamycin, it induced islet-specific immunological tolerance which allowed the acceptance of a second graft without additional immunosuppression. This regimen dramatically reduced the alloantigen-specific IFN-γ-producing T cells in the spleen, and increased regulatory T cells both at the graft site and in the spleen. Therefore, we propose that short-term treatment of low-dose bortezomib and rapamycin could be a new tolerance-promoting immunosuppressive regimen for allogeneic islet transplantation. [ABSTRACT FROM AUTHOR]

Abstract: Protein crystallization has long been considered to be an important strategy that offers the high stability and potency for the therapeutic proteins. The difficulty of crystallizing macromolecules such as proteins, however, is well known. Because of their flexibility, glycoproteins are more difficult to crystallize than non-glycosylated proteins. For this reason, the crystallization process for glycoproteins remains a major obstacle in the industrial production of many important therapeutic proteins. In this study, we have developed crystallization process for glycoproteins using α-lactalbumin as a model protein. This model protein was microcrystallized using a pH-shift method in polyethylene glycol (PEG) solution as a mother liquor. This microcrystallization process produced uniform and micron-sized α-lactalbumin microcrystals. The morphology of these crystals was spherical, and the mean size was about 1–2μm when observed by scanning electron microscope (SEM). X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) showed that the microcrystals had a greater degree of crystallinity than α-lactalbumin lyophilized amorphous powder. These results suggest that the pH-shift crystallization in PEG solution could be applied to other glycoproteins, thereby increasing the stability of the important glycoprotein therapeutic agents. [Copyright &y& Elsevier]

Islet transplantation is one of the most beneficial treatment modality to treat type 1 diabetic patients with frequent hypoglycemic unawareness. In clinical setting, human islets are infused via portal vein and are settled in the end-portal venules in the liver. However, mouse islets are transplanted into kidney subcapsule or liver through direct portal vein. These conventional transplantation methods have several drawbacks such as different physiological environments around the transplanted islets in kidney subcapsule from the liver and high mortality rate in direct portal vein approach. In this study, we introduced murine intrahepatic islet transplantation method via cecal vein to have the same surgical operation route in humans as well as guaranteeing low mortality rate after islet transplantation. With this protocol, consistent normoglycemia can be obtained in diabetic mice, while keeping operation-related mortality extremely low. This approach with easier accessibility and low mortality will make murine intrahepatic islet transplantation a useful model for studying immunological mechanisms such as strong innate and adaptive immune responses that occur in human islet transplantation. [ABSTRACT FROM AUTHOR]

Abstract: Tau is a main component of the aberrant paired helical filaments (PHF) found in Alzheimer''s disease (AD). It has also been reported to enhance oxidative stress, which is a major factor in the pathogenesis of neurodegenerative diseases. However, protective functions of Tau have recently been reported, including antagonizing apoptosis, in addition to its role in stabilizing microtubules. In this study, the interaction between Tau and triose phosphate isomerase (TPI) in a normal, nondisease state as well as in a neurodegeneration state was examined and demonstrated for the first time. More importantly, we also showed that Tau protects TPI against oxidative damage. An oxidative stress-induced decrease in the activity of TPI was attenuated in Tau-overexpressing cells, indicating that Tau protects TPI against oxidative damage. By contrast, the activity of TPI was decreased in Tau-transgenic (Tg) mice compared to non-Tg (NTg) mice even though protein levels were not changed in both groups. Some TPIs were found on the PHF in Tg mice, which explains the decrease in the activity of TPI. Taken together, we concluded that while Tau binds and protects TPI in normal cells, and conversely, the formation of PHF induced by Tau phosphorylation trap some TPI and trigger the functional loss of TPI in the development of neurodegenerative diseases. Our results provide new insights into understanding the in-depth involvement of Tau in the development of neurodegenerative disorders. [Copyright &y& Elsevier]