Summary Macrophages/monocytes and the proinflammatory mediators, such as tumour necrosis factor (TNF)‐α, prostaglandin E2 (PGE2), macrophage inflammatory protein (MIP)‐1α and MIP‐1α, play a critical role in the progression of immunological disorders including rheumatoid arthritis, Behçet’s disease and Crohn’s disease. In addition, the nicotinic acetylcholine receptor‐α7 (α7nAChR) subunit is an essential regulator of inflammation. In this study, we evaluated the expression of the α7nAChR subunit on human peripheral monocytes and the effect of nicotine on the production of these proinflammatory mediators by activated monocytes. Fluorescein isothiocyanate (FITC)‐labelled α‐bungarotoxin demonstrated the cell surface expression of the α7nAchR subunit. Pretreatment with low‐dose nicotine caused inhibition of TNF‐α, PGE2, MIP‐1α and MIP‐1α production, and mRNA expression of TNF‐α, MIP‐1α and MIP‐1α and COX‐2 in lipopolysaccharide (LPS)‐activated monocytes. These suppressive effects of nicotine were caused at the transcriptional level and were mediated through α7nAChR. Nicotine suppressed the phosphorylation of I‐κB, and then inhibited the transcriptional activity of nuclear factor‐κB. These immunosuppressive effects of nicotine may contribute to the regulation of some immune diseases.

Summary Involvement of excessive

This study demonstrates that CDDP specifically induces apoptosis via activation of caspases and the other anticancer drugs induce death of HOS cells via different signaling pathways. It also demonstrates that caspase-8 is a key molecule in the earliest stage of the signaling pathway of CDDP-induced apoptosis of HOS cells, and caspase-3 works downstream of caspase-8.

Epithelial progenitors were successfully induced in vitro from ES cells and were applicable as grafts for treating corneal epithelial injury. ES cells may become an unlimited donor source of corneal epithelial cells for corneal transplantation and may restore useful vision in patients with a deficiency of limbal epithelial cells. This is an important first trial toward assessing the use of ES cells to reconstruct corneal epithelial cells.

SummaryExcessive T helper type 1 (Th1) cell activity has been reported in Behçet's disease (BD). Recently, association of Th17 cells with certain autoimmune diseases was reported, and we thus investigated circulating Th17 cells in BD.

BAI1 (brain-specific angiogenesis inhibitor 1) was originally isolated as a p53-target gene specifically expressed in brain. To clarify its function, we have been searching for cellular proteins that associate with the cytoplasmic domain of BAI1. Using its intracellular carboxyl terminus as “bait” in a yeast two-hybrid system, we isolated a cDNA clone named BAIAP2 whose nucleotide sequence would encode a 521-amino acid protein showing significant homology to a 58/53-kDa substrate of insulin-receptor kinase in the hamster. As the expression profile of BAIAP2 examined by Northern blot analysis was almost identical to that of BAI1, BAIAP2 appears to be active mainly in neurons. In vitro binding assays confirmed that a proline-rich cytoplasmic fragment of BAI1 interacted with the Src homology 3 (SH3) domain of BAIAP2. Double-color immunofluorescent analysis revealed that BAIAP2 was localized at the cytoplasmic membrane when it was coexpressed with BAI1 in COS-7 cells; BAIAP2 not associated with BAI1 was diffused in the cytoplasm. Predominant localization of BAI1 protein in a sub-cellular fraction enriched in growth cones indicated a possible role of BAI1 as a cell adhesion molecule inducing growth cone guidance. As a protein partner of BAI1, BAIAP2 may represent an important link between membrane and cytoskeleton in the process of neuronal growth.

SummaryWe have found previously that Txk, a member of the Tec family tyrosine kinases, is involved importantly in T helper 1 (Th1) cytokine production. However, how Txk regulates interferon (IFN)-g gene transcription in human T lymphocytes was not fully elucidated. In this study, we identified poly(ADPribose) polymerase 1 (PARP1) and elongation factor 1a (EF-1a) as Txkassociated molecules that bound to the Txk responsive element of the IFN-g gene promoter. Txk phosphorylated EF-1a and PARP1 formed a complex with them, and bound to the IFN-g gene promoter in vitro. In particular, the N terminal region containing the DNA binding domain of PARP1 was important for the trimolecular complex formation involving Txk, EF-1a and PARP1. Several mutant Txk which lacked kinase activity were unable to form the trimolecular complex. A PARP1 inhibitor, PJ34, suppressed IFN-g but not interleukin (IL)-4 production by normal peripheral blood lymphocytes (PBL). Multi-colour confocal analysis revealed that Txk and EF-1a located in the cytoplasm in the resting condition. Upon activation, a complex involving Txk, EF-1a and PARP1 was formed and was located in the nucleus. Collectively, Txk in combination with EF-1a and PARP1 bound to the IFN-g gene promoter, and exerted transcriptional activity on the IFN-g gene.

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