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Fumio Fukai

Publications and source records attributed to Fumio Fukai.

11 recordsLinked to original sources
PubMed2006

IL-27 induces Th1 differentiation via p38 MAPK/T-bet- and intercellular adhesion molecule-1/LFA-1/ERK1/2-dependent pathways.

IL-27, a novel member of the IL-6/IL-12 family, activates both STAT1 and STAT3 through its receptor, which consists of WSX-1 and gp130 subunits, resulting in positive and negative regulations of immune responses. We recently demonstrated that IL-27 induces Th1 differentiation through ICAM-1/LFA-1 interaction in a STAT1-dependent, but T-bet-independent mechanism. In this study, we further investigated the molecular mechanisms by focusing on p38 MAPK and ERK1/2. IL-27-induced Th1 differentiation was partially inhibited by lack of T-bet expression or by blocking ICAM-1/LFA-1 interaction with anti-ICAM-1 and/or anti-LFA-1, and further inhibited by both. Similarly, the p38 MAPK inhibitor, SB203580, or the inhibitor of ERK1/2 phosphorylation, PD98059, partially suppressed IL-27-induced Th1 differentiation and the combined treatment completely suppressed it. p38 MAPK was then revealed to be located upstream of T-bet, and SB203580, but not PD98059, inhibited T-bet-dependent Th1 differentiation. In contrast, ERK1/2 was shown to be located downstream of ICAM-1/LFA-1, and PD98059, but not SB203580, inhibited ICAM-1/LFA-1-dependent Th1 differentiation. Furthermore, it was demonstrated that STAT1 is important for IL-27-induced activation of ERK1/2, but not p38 MAPK, and that IL-27 directly induces mRNA expression of growth arrest and DNA damage-inducible 45gamma, which is known to mediate activation of p38 MAPK. Finally, IL-12Rbeta2 expression was shown to be up-regulated by IL-27 in both T-bet- and ICAM-1/LFA-1-dependent mechanisms. Taken together, these results suggest that IL-27 induces Th1 differentiation via two distinct pathways, p38 MAPK/T-bet- and ICAM-1/LFA-1/ERK1/2-dependent pathways. This is in contrast to IL-12, which induces it via only p38 MAPK/T-bet-dependent pathway.

Animals↗
PubMed2006

IL-27 suppresses CD28-mediated [correction of medicated] IL-2 production through suppressor of cytokine signaling 3.

IL-27 is a novel IL-6/IL-12 family cytokine that not only plays a role in the early regulation of Th1 differentiation, but also exerts an inhibitory effect on immune responses, including the suppression of proinflammatory cytokine production. However, the molecular mechanism by which IL-27 exerts the inhibitory effect remains unclear. In this study we demonstrate that IL-27 inhibits CD28-mediated IL-2 production and that suppressor of cytokine signaling 3 (SOCS3) plays a critical role in the inhibitory effect. Although IL-27 enhanced IFN-gamma production from naive CD4+ T cells stimulated with plate-coated anti-CD3 and anti-CD28 in the presence of IL-12, IL-27 simultaneously inhibited CD28-mediated IL-2 production. Correlated with the inhibition, IL-27 was shown to augment SOCS3 expression. Analyses using various mice lacking a signaling molecule revealed that the inhibition of IL-2 production was dependent on STAT1, but not on STAT3, STAT4, and T-bet, and was highly correlated with the induction of SOCS3 expression. Similar inhibition of CD28-mediated IL-2 production and augmentation of SOCS3 expression by IL-27 were observed in a T cell hybridoma cell line, 2B4. Forced expression of antisense SOCS3 or dominant negative SOCS3 in the T cell line blocked the IL-27-inudced inhibition of CD28-mediated IL-2 production. Furthermore, pretreatment with IL-27 inhibited IL-2-mediated cell proliferation and STAT5 activation, although IL-27 hardly affected the induction level of CD25 expression. These results suggest that IL-27 inhibits CD28-mediated IL-2 production and also IL-2 responses, and that SOCS3, whose expression is induced by IL-27, plays a critical role in the inhibitory effect in a negative feedback mechanism.

Animals↗
PubMed2005

Milk growth factor (MGF) induces transformation into ATDC5 cells, prechondrocytes, and cooperates with retinoic acid to transform the cells into new forms.

The effects of milk growth factor (MGF) showed the transformation of ATDC5 prechondrocytes and differed from that of retinoic acid (RA) as follows. MGF (200 ng/ml) did not suppress the proliferation of ATDC5 cells, though RA (1 x 10(-7) M) suppressed the cell proliferation. However, MGF showed the result as RA, which was verified to suppress the production of proteoglycan. The synthesis of vimentin in ATDC5 cells was slightly induced by RA, but its withdrawal induced the large-scale induction and the fibril formation of vimentin, which may indicate that the cells became fibroblastic cells, namely dedifferentiation. MGF, which hardly induced the vimentin synthesis in ATDC5 cells, induced its synthesis under control by the withdrawal. MGF suppressed the synthesis of alpha-smooth muscle actin (alpha-SM-actin), which was apt to reverse in its withdrawal. However, RA did not affect this synthesis of ATDC5 cells. The combination of MGF and RA enlarged the cells and enhanced the synthesis of vimentin due to RA under control, however, almost terminated alpha-SM-actin-synthesis in the cells. And its effect is almost irreversible. Furthermore, the combination of MGF and RA prevented the induction of fibroblasts due to RA in the cells. And the withdrawal of the mixture transformed prechondrocytes into hypertrophic cells. Then, MGF contributes to bone metabolism in prechondrocyte.

Actins↗
PubMed2005

A role for IL-27 in early regulation of Th1 differentiation.

IL-27 is a novel IL-6/IL-12 family cytokine that is considered to play a role in Th1 differentiation, whereas the exact role of IL-27 in Th1 differentiation and its molecular mechanism remain unclear. In this study we demonstrate a role for IL-27 in the early regulation of Th1 differentiation and its possible molecular mechanism. The ability of IL-27 to induce Th1 differentiation was most prominent under Th1-polarizing conditions, but without IL-12 in a STAT4- and IFN-gamma-independent manner, and was overruled by IL-12 dose dependently. IL-27 rapidly up-regulated the expression of ICAM-1 on naive CD4+ T cells, but not on APCs, and blocking Abs against ICAM-1 and LFA-1 inhibited the IL-27-induced Th1 differentiation. Although IL-27 augmented T-bet expression in naive CD4+ T cells as previously reported, T-bet was not necessary for the IL-27-induced rapid up-regulation of ICAM-1 expression and Th1 differentiation. In contrast, STAT1 was revealed to be required for the rapid up-regulation of ICAM-1 expression and Th1 differentiation by directly mediating the transcriptional enhancement of ICAM-1 gene expression. These results indicate that IL-27 efficiently induces Th1 differentiation under Th1-polarizing conditions, but without IL-12, and that the rapid up-regulation of ICAM-1 expression on naive CD4+ T cells is important for the IL-27-induced Th1 differentiation. Considering that IL-27 is produced from macrophages and DCs earlier than IL-12, the present results suggest that IL-27 may play a pivotal role in early efficient induction of Th1 differentiation until sufficient IL-12 is produced.

Animals↗
PubMed2005

Cell sheet engineering: recreating tissues without biodegradable scaffolds.

While tissue engineering has long been thought to possess enormous potential, conventional applications using biodegradable scaffolds have limited the field's progress, demonstrating a need for new methods. We have previously developed cell sheet engineering using temperature-responsive culture dishes in order to avoid traditional tissue engineering approaches, and their related shortcomings. Using temperature-responsive dishes, cultured cells can be harvested as intact sheets by simple temperature changes, thereby avoiding the use of proteolytic enzymes. Cell sheet engineering therefore allows for tissue regeneration by either direct transplantation of cell sheets to host tissues or the creation of three-dimensional structures via the layering of individual cell sheets. By avoiding the use of any additional materials such as carrier substrates or scaffolds, the complications associated with traditional tissue engineering approaches such as host inflammatory responses to implanted polymer materials, can be avoided. Cell sheet engineering thus presents several significant advantages and can overcome many of the problems that have previously restricted tissue engineering with biodegradable scaffolds.

Animals↗
PubMed2004

A fibronectin fragment induces tumor necrosis factor production of rat basophilic leukemia cells.

Proteolytic digest of fibronectin (FN), but not intact FN, induced TNF-alpha secretion of rat basophilic leukemia (RBL-2H3) cells. As a result of the identification of FN fragment responsible for TNF-alpha secretion, a 30-kDa fragment derived from the carboxyl-terminal heparin-binding (Hep 2) domain of FN was isolated from the FN digest. The TNF-alpha secretion was abrogated by treatment of RBL-2H3 cells with cycloheximide, indicating the de novo synthesis of TNF-alpha, but not with polymyxin B, excluding the possible TNF-alpha induction by some contaminated lipopolysaccharides. A 22-mer synthetic peptide originated from the Hep 2 domain, termed FNIII14, which has been found to negatively modulate the beta1 integrin activation, had the ability to induce TNF-alpha production, whereas this activity of FNIII14 disappeared by shuffling a YTIYVIAL sequence essential for the integrin-inactivating activity. FNIII14 suppressed the spreading of RBL-2H3 cells on FN substrate, wherein RBL-2H3 cell proliferation was inhibited with FNIII14 in a dose-dependent manner. Thus, it appears that FN fragments containing the YTIYVIAL anti-adhesive site affect the activation status of RBL-2H3 mast cells, characterized by the stimulation of TNF-alpha production and growth suppression, probably due to negative regulation of beta1 integrin activity.

Animals↗
PubMed2004

An indispensable role for STAT1 in IL-27-induced T-bet expression but not proliferation of naive CD4+ T cells.

IL-27 is a novel IL-12 family member that plays a role in the early regulation of Th1 initiation, induces proliferation of naive CD4+ T cells, and synergizes with IL-12 in IFN-gamma production. It has been recently reported that IL-27 induces T-bet and IL-12Rbeta2 expression through JAK1/STAT1 activation. In the present study, we further investigated the JAK/STAT signaling molecules activated by IL-27 and also the role of STAT1 in IL-27-mediated responses using STAT1-deficient mice. In addition to JAK1 and STAT1, IL-27-activated JAK2, tyrosine kinase-2, and STAT2, -3, and -5 in naive CD4+ T cells. The activation of STAT2 and STAT5, but not of STAT3, was greatly diminished in STAT1-deficient naive CD4+ T cells. Comparable proliferative response to IL-27 was observed between STAT1-deficient and wild-type naive CD4+ T cells. In contrast, IL-27 hardly induced T-bet and subsequent IL-12Rbeta2 expression, and synergistic IFN-gamma production by IL-27 and IL-12 was impaired in STAT1-deficient naive CD4+ T cells. Moreover, IL-27 augmented the expression of MHC class I on naive CD4+ T cells in a STAT1-dependent manner. These results suggest that IL-27 activates JAK1 and -2, tyrosine kinase-2, STAT1, -2, -3, and -5 in naive CD4+ T cells and that STAT1 plays an indispensable role in IL-27-induced T-bet and subsequent IL-12Rbeta2 expression and MHC class I expression as well but not proliferation, while STAT3 presumably plays an important role in IL-27-induced proliferation.

Adjuvants, Immunologic↗
PubMed2004

Induction of IgG2a class switching in B cells by IL-27.

IL-27 is a novel IL-12 family member that plays a role in the early regulation of Th1 initiation. However, its role in B cells remains unexplored. We here show a role for IL-27 in the induction of T-bet expression and regulation of Ig class switching in B cells. Expression of WSX-1, one subunit of IL-27R, was detected at the mRNA level in primary mouse spleen B cells, and stimulation of these B cells by IL-27 rapidly activated STAT1. IL-27 then induced T-bet expression and IgG2a, but not IgG1, class switching in B cells activated with anti-CD40 or LPS. In contrast, IL-27 inhibited IgG1 class switching induced by IL-4 in activated B cells. Similar induction of STAT1 activation, T-bet expression and IgG2a class switching was observed in IFN-gamma-deficient B cells, but not in STAT1-deficient ones. The induction of IgG2a class switching was abolished in T-bet-deficient B cells activated with LPS. These results suggest that primary spleen B cells express functional IL-27R and that the stimulation of these B cells by IL-27 induces T-bet expression and IgG2a, but not IgG1, class switching in a STAT1-dependent but IFN-gamma-independent manner. The IL-27-induced IgG2a class switching is highly dependent on T-bet in response to T-independent stimuli such as LPS. Thus, IL-27 may be a novel attractive candidate as a therapeutic agent against diseases such as allergic disorders by not only regulating Th1 differentiation but also directly acting on B cells and inducing IgG2a class switching.

Animals↗
PubMed2002

Fibronectin peptides derived from two distinct regions stimulate adipocyte differentiation by preventing fibronectin matrix assembly.

Here, we show that fibronectin (FN) peptides derived from two distinct regions promote the insulin-induced adipocyte differentiation of ST-13 cells by preventing FN fibrillogenesis. ST-13 cells formed numerous FN fibrils under nonadipogenic conditions, whereas this FN fibrillogenesis was suppressed by adipose induction with insulin. The insulin-induced adipocyte differentiation was promoted by an amino-terminal 24-kDa fragment of FN, accompanied by further suppression of FN fibrillogenesis. The 24 K fragment prevented FN matrix assembly by direct incorporation into the FN matrix. Like the 24 K fragment, a peptide from the 14th type III repeat, termed FNIII14, which suppressed the integrin alpha 5 beta 1-mediated adhesion of ST-13 cells to FN, accelerated the adipocyte differentiation by preventing FN fibrillogenesis without direct incorporation into the FN matrix. FNIII14 induced the conformation change of beta1 integrins of K562 cells from active to resting, as judged by FACS analysis using a monoclonal antibody AG89 directed to an active beta1 integrin-dependent epitope. Binding of a (125)I-labeled FN fragment containing the RGD cell adhesive site to ST-13 cell surface was dissociated by FNIII14, with a concomitant binding of FNIII14 itself to the cell surface. The affinity labeling of ST-13 cells using biotinylated FNIII14 showed that FNIII14 specifically bound to a nonintegrin membrane protein with M(r) of around 50 kDa. Thus, the results indicated that prevention of FN fibrillogenesis by the 24 K Fib 1 fragment and FNIII14 caused the promotion of adipocyte differentiation of ST-13 cells and that the former was due to the direct incorporation into the FN matrix and that the latter might be interpreted by negative regulation of FN receptor alpha 5 beta 1 activity.

Adipocytes↗
PubMed2002

A new type of antimetastatic peptide derived from fibronectin.

PURPOSE: We found previously that fibronectin (FN) has a cryptic functional site (YTIYVIAL sequence within the 14th type III repeat) opposing cell adhesion to extracellular matrix. A 22-mer FN peptide containing this site, termed FNIII14, inhibits beta1 integrin-mediated adhesion without binding to integrins. The present study shows that FNIII14 has the potential to prevent lymphoma cell metastasis. EXPERIMENTAL DESIGN: Antimetastatic effect of FNIII14 has been evaluated through in vitro or in vivo experiments. RESULTS: FNIII14 inhibited the integrin alpha4beta1-mediated B lymphoma Ramos cell adhesion to VCAM-1 on venule endothelial cells, as well as to FN. Murine T lymphoma L5178Y-ML25 cells, which are known to metastasize to liver and spleen, preferentially adhered to vitronectin (VN) and migrated toward VN concentration gradients. FNIII14 abrogated both the integrin alphavbeta3-mediated adhesion and migration of L5178Y-ML25 cells. Inhibition of the alphavbeta3mediated L5178Y-ML25 cell adhesion by FNIII14 was reversed by phenylarsine oxide, a protein tyrosine phosphatase inhibitor. In addition, FNIII14 abrogated the VN-stimulated tyrosine phosphorylation of intracellular signaling proteins, including focal adhesion kinase (p125(FAK)) and paxillin, suggesting that such a diversity of FNIII14 effects might be because of the negative regulation of p125(FAK) and paxillin tyrosine phosphorylation, which has been involved in adhesion signals transduced by different integrins. The in vivo experiment using a murine metastasis model showed that FNIII14 would inhibit liver and spleen metastases of L5178Y-ML25 cells at a dose much lower than that of RGDS. CONCLUSIONS: FNIII14 might be applicable as a new type of antimetastatic agent distinct from integrin-binding peptides.

Animals↗