Kohichiro Yoshino

Cardiac hypertrophy is inhibited by antagonism of ADAM12 processing of HB-EGF: Metalloproteinase inhibitors as a new therapy

G-protein–coupled receptor (GPCR) agonists are well-known inducers of cardiac hypertrophy. We found that the shedding of heparin-binding epidermal growth factor (HB-EGF) resulting from metalloproteinase activation and subsequent transactivation of the epidermal growth factor receptor occurred when cardiomyocytes were stimulated by GPCR agonists, leading to cardiac hypertrophy. A new inhibitor of HB-EGF shedding, KB-R7785, blocked this signaling. We cloned a disintegrin and metalloprotease 12 (ADAM12) as a specific enzyme to shed HB-EGF in the heart and found that dominant-negative expression of ADAM12 abrogated this signaling. KB-R7785 bound directly to ADAM12, suggesting that inhibition of ADAM12 blocked the shedding of HB-EGF. In mice with cardiac hypertrophy, KB-R7785 inhibited the shedding of HB-EGF and attenuated hypertrophic changes. These data suggest that shedding of HB-EGF by ADAM12 plays an important role in cardiac hypertrophy, and that inhibition of HB-EGF shedding could be a potent therapeutic strategy for cardiac hypertrophy.

Identification and characterization of novel mouse and human ADAM33s with potential metalloprotease activity.

The ADAM family of membrane-anchored proteins has a unique domain structure, with each containing a disintegrin and metalloprotease (ADAM) domain. We have isolated mouse and human cDNAs encoding a novel member of the ADAM family. The mouse and human predicted proteins consisted of 797 and 813 amino acids, respectively, and they shared 70% homology of the entire amino acid sequence. The mouse ADAM gene exists at a single gene locus. The human gene was ubiquitously expressed in tissues other than liver, was mapped to human chromosome 20p13, and was found to consist of 22 exons. Both proteins have domain organization identical to that of previously reported members of the ADAM family, and contain the typical zinc-binding consensus sequence (HEXGHXXGXXHD) in their metalloprotease domain and a pattern of cysteine localization (C(x)(3)C(x)(5)C(x)(5)CxC(x)(8)C) in their EGF-like domain that is typical of an EGF-like motif. The human protein shows homology with Xenopus ADAM13 (44%), human ADAM19 (40%), and human ADAM12 (39%). From the results of phylogenic analysis based on primary amino acid sequence and distribution of the mRNA, these novel ADAM genes were thus named ADAM33.

Cutting Edge: IL-18-Transgenic Mice: In Vivo Evidence of a Broad Role for IL-18 in Modulating Immune Function

IL-18 has been shown to be a strong cofactor for Th1 T cell development. However, we previously demonstrated that when IL-18 was combined with IL-2, there was a synergistic induction of a Th2 cytokine, IL-13, in both T and NK cells. More recently, we and other groups have reported that IL-18 can potentially induce IgE, IgG1, and Th2 cytokine production in murine experimental models. Here, we report on the generation of IL-18-transgenic (Tg) mice in which mature mouse IL-18 cDNA was expressed. CD8+CD44high T cells and macrophages were increased, but B cells were decreased in these mice while serum IgE, IgG1, IL-4, and IFN-γ levels were significantly increased. Splenic T cells in IL-18 Tg mice produced higher levels of IFN-γ, IL-4, IL-5, and IL-13 than control wild-type mice. Thus, aberrant expression of IL-18 in vivo results in the increased production of both Th1 and Th2 cytokines.

Contribution of IL-18 to Th1 Response and Host Defense Against Infection by Mycobacterium tuberculosis: A Comparative Study with IL-12p40

The present study was conducted to critically determine the protective role of IL-18 in host response to Mycobacterium tuberculosis infection. IL-18-deficient (knockout (KO)) mice were slightly more prone to this infection than wild-type (WT) mice. Sensitivity of IL-12p40KO mice was lower than that of IL-12p40/IL-18 double KO mice. IFN-γ production caused by the infection was significantly attenuated in IL-18KO mice compared with WT mice, as indicated by reduction in the levels of this cytokine in sera, spleen, lung, and liver, and its synthesis by spleen cells restimulated with purified protein derivatives. Serum IL-12p40 level postinfection and its production by peritoneal exudate cells stimulated with live bacilli were also significantly lower in IL-18KO mice than WT mice, suggesting that attenuated production of IFN-γ was secondary to reduction of IL-12 synthesis. However, this was not likely the case, because administration of excess IL-12 did not restore the reduced IFN-γ production in IL-18KO mice. In further studies, IL-18 transgenic mice were more resistant to the infection than control littermate mice, and serum IFN-γ level and its production by restimulated spleen cells were increased in the former mice. Taken together, our results indicate that IL-18 plays an important role in Th1 response and host defense against M. tuberculosis infection although the contribution was not as profound as that of IL-12p40.

Matrix Metalloproteinase and αvβ3 Integrin–Dependent Vascular Smooth Muscle Cell Invasion Through a Type I Collagen Lattice

Abstract —Smooth muscle cell (SMC) migration from the tunica media to the intima is a key event in the development of atherosclerotic lesions and in restenosis after angioplasty. SMCs require not only migratory but also degradative abilities that enable them to migrate through extracellular matrix proteins, which surround and embed these cells. We used a collagen type I lattice as a coating on top of a porous filter as a matrix barrier in a chamber to test the invasive behavior of SMCs in response to a chemoattractant (invasion assay) and compared that behavior with simple SMC migration through collagen type I–coated filters (migration assay). Inhibitors of matrix metalloproteinase, KB-R8301, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), TIMP-2, and peptide 74, attenuated platelet-derived growth factor-BB (PDGF-BB)–directed SMC invasion across the collagen lattice, whereas no effect was seen with these inhibitors on simple SMC migration through collagen-coated filters. RGD peptide inhibited SMC invasion but did not affect SMC migration. Anti-αvβ3 integrin antibody attenuated PDGF-BB–directed SMC invasion, whereas other antibodies against RGD-recognizing integrins, namely αvβ5 and α5, had no effect. None of these antibodies had any effect on simple SMC migration. RGD peptide and anti-αvβ3 antibody inhibited the attachment and spreading of SMCs on denatured collagen but not on native collagen. These findings indicate that there is a difference in the mechanisms between simple SMC migration across a collagen-coated filter and SMC invasion through a fibrillar collagen barrier. A proteolytic process is required for SMC invasion, and the degradation of matrix proteins alters the relationship between matrix protein molecules and SMC surface integrins.

Comparison of the Cancer Gene Targeting and Biochemical Selectivities of All Targeted Kinase Inhibitors Approved for Clinical Use

The anti-proliferative activities of all twenty-five targeted kinase inhibitor drugs that are in clinical use were measured in two large assay panels: (1) a panel of proliferation assays of forty-four human cancer cell lines from diverse tumour tissue origins; and (2) a panel of more than 300 kinase enzyme activity assays. This study provides a head-on comparison of all kinase inhibitor drugs in use (status Nov. 2013), and for six of these drugs, the first kinome profiling data in the public domain. Correlation of drug activities with cancer gene mutations revealed novel drug sensitivity markers, suggesting that cancers dependent on mutant CTNNB1 will respond to trametinib and other MEK inhibitors, and cancers dependent on SMAD4 to small molecule EGFR inhibitor drugs. Comparison of cellular targeting efficacies reveals the most targeted inhibitors for EGFR, ABL1 and BRAF(V600E)-driven cell growth, and demonstrates that the best targeted agents combine high biochemical potency with good selectivity. For ABL1 inhibitors, we computationally deduce optimized kinase profiles for use in a next generation of drugs. Our study shows the power of combining biochemical and cellular profiling data in the evaluation of kinase inhibitor drug action.

Bone Malformations in Interleukin-18 Transgenic Mice†

The in vivo effects of IL‐18 on bone metabolism were investigated by histopathology in IL‐18 transgenic mice. Deformed cortical bone and decreased turnover rate of lumbar trabecular bone are consistent with increased expression of IFN‐γ and IL‐18 in the bone marrow.

Structure--activity relationships of azasugar-based MMP/ADAM inhibitors.

In order to investigate structure-activity relationships of azasugar series toward metalloproteinases, we synthesized and evaluated several azasugar-based compounds. As a result, it was found that 4-phenoxybenzene derivative 3 having 2R,3R,4R,5S-configurations exhibited most potent inhibitory activities against matrix metalloproteinase-1, -3 and -9 and TACE.

A metalloproteinase inhibitor prevents acute graft-versus-host disease while preserving the graft-versus-leukaemia effect of allogeneic bone marrow transplantation

We examined the effect of a hydroxamic acid‐based matrix metalloproteinase inhibitor (KB‐R7785), which we previously demonstrated to have a potent ameliorating effect on acute graft‐versus‐host disease (GVHD), and on the graft‐versus‐leukaemia (GVL) effect of allogeneic bone marrow transplantation (BMT). KB‐R7785 was administered to (C57BL/6 × BALB/c) F1 (CBF1) mice that had been inoculated with IgE‐producing B53 hybridoma cells of BALB/c origin as a model tumour, along with or without transplantation of C57BL/6 (B6) bone marrow cells and spleen cells (BMS). Administration of KB‐R7785 without BMS significantly prolonged the survival of B53‐inoculated CBF1 mice by inhibiting the infiltration of B53 cells into the liver and spleen. Transplantation of B6 BMS without KB‐R7785 resulted in the death of most recipients due to acute GVHD while efficiently eliminating B53 cells. Administration of KB‐R7785 along with B6 BMS resulted in a 50% survival of B53‐inoculated CBF1 mice over 50 d without histological manifestations of acute GVHD or residual B53 cells. These results indicate the beneficial effects of KB‐R7785 that inhibit tumour infiltration and prevent acute GVHD while preserving the GVL effect of allogeneic BMT.

Matrix metalloproteinase inhibitor reduces apoptosis induction of bone marrow cells in MDS‐RA

Abstract:  Background and objectives: We examined the involvement of apoptosis with myelodysplastic syndrome (MDS) accompanied by peripheral cytopenias despite normo‐hypercellular bone marrow. Materials and methods: Bone marrow smears from 31 patients with MDS‐refractory anemia (RA) and five normal controls were stained using the in situ end labeling (ISEL) method. Next, the inhibitory effects of a caspase‐3 inhibitor, matrix metalloproteinase inhibitor (MMPI), anti‐tumor necrosis factor (TNF)‐α or anti‐Fas antibody upon the apoptosis induction in overnight cultures of bone marrow cells from the patients were examined. Further, TNF‐α, transforming growth factor (TGF)‐β and soluble Fas ligand (sFasL) concentrations in culture supernatants of the cells were assessed by enzyme‐linked immunosorbent assay (ELISA). Results: The incidence of ISEL‐positive cells among MDS patients was significantly higher than in normal controls (50.8 ± 14.0% vs. 11.3 ± 2.4%; P < 0.0001). A caspase‐3 inhibitor reduced significantly the ISEL‐positive rates (32.6 ± 15.2% vs. 50.2 ± 16.5%; P < 0.0001). Anti‐TNF‐α or anti‐Fas antibody reduced the ISEL‐positive rates significantly (28.2 ± 6.0%, 29.2 ± 5.8%, vs. 44.2 ± 3.4%, P < 0.001, P = 0.001, respectively). KB‐R7785 also significantly decreased the ISEL‐positive rates (18.0 ± 9.3% vs. 43.6 ± 14.0%; P < 0.0001). The concentration of TNF‐α was significantly reduced by KB‐R7785 (P < 0.05), whereas that of TGF‐β was not. Concentration of sFasL was under detectable level in the present assay system. The derivatives of KB‐R7785 that can be administrated orally showed inhibitory effect on apoptosis induction as well. Conclusions: These findings suggest that MMPIs inhibits the apoptosis induction of MDS bone marrow cells via the inhibition of TNF‐α and probably sFasL secretion, and that MMPIs can be used to control the abnormal induction of apoptosis in MDS.