The effects of ten 10-phenyl-[11]cytochalasans produced by Phomopsis sp. including novel compounds haing 5, 7-or 6, 7-glycol structures and their derivatives, on the cell morphology and actin distribution in C3H-2K cells, as well as on lymphocyte capping and actin polymerization, were examined. The structure-activity relationship reported in the previous papars has been confirmed. The novel glycol type compounds showed little or no activity, suggesting the importance of the perhydroisoindol-1-one nucleus for the manifestation of the cytochalasin actions.
For clinical trials of therapeutic monoclonal antibodies (mAbs) to be successful, their efficacy needs to be adequately evaluated in preclinical experiments. However, in many cases it is difficult to evaluate the candidate mAbs using animal disease models because of lower cross-reactivity to the orthologous target molecules. In this study we have established a novel humanized Castleman's disease mouse model, in which the endogenous interleukin-6 receptor gene is successfully replaced by human IL6R and human IL6 is overexpressed. We have also demonstrated the therapeutic effects of an antibody that neutralizes human IL6R, tocilizumab, on the symptoms in this mouse model. Plasma levels of human soluble IL6R and human IL6 were elevated after 4-week treatment of tocilizumab in this mouse model similarly to the result previously reported in patients treated with tocilizumab. Our mouse model provides us with a novel means of evaluating the in vivo efficacy of human IL6R-specific therapeutic agents.
Abstract Scratching is an important factor exacerbating skin lesions through the so‐called itch‐scratch cycle in atopic dermatitis ( AD ). In mice, interleukin ( IL )‐31 and its receptor IL ‐31 receptor A ( IL ‐31 RA ) are known to play a critical role in pruritus and the pathogenesis of AD ; however, study of their precise roles in primates is hindered by the low sequence homologies between primates and mice and the lack of direct evidence of itch sensation by IL ‐31 in primates. We showed that administration of cynomolgus IL ‐31 induces transient scratching behaviour in cynomolgus monkeys and by that were able to establish a monkey model of scratching. We then showed that a single subcutaneous injection of 1 mg/kg nemolizumab, a humanized anti‐human IL ‐31 RA monoclonal antibody that also neutralizes cynomolgus IL ‐31 signalling and shows a good pharmacokinetic profile in cynomolgus monkeys, suppressed the IL ‐31‐induced scratching for about 2 months. These results suggest that the IL ‐31 axis and IL ‐31 RA axis play as critical a role in the induction of scratching in primates as in mice and that the blockade of IL ‐31 signalling by an anti‐human IL ‐31 RA antibody is a promising therapeutic approach for treatment of AD . Nemolizumab is currently under investigation in clinical trials.
Chicken skeletal muscle beta-actinin, previously reported to bind the slow-exchanging (pointed) ends of actin filaments was purified to homogeneity. By two dimensional gel electrophoresis, it consists of two subunits, beta I (35 kDa) and beta II (32 kDa), and each subunit has two isoforms. The amino acid sequences of V8 protease-digested peptides of beta I were nearly identical with those of portions of the muscle end-blocking protein Cap Z alpha, although several amino acids were different from those deduced from cDNA sequences (Casella, J.F., Casella, S.J., Hollands, J.A., Caldwell, J.E., and Cooper, J.A. (1989) Proc. Natl. Acad. Sci. U.S.A. 86, 5800-5804). The amino acid sequences of two peptides from beta II were completely identical with portions of Cap Z beta deduced from cDNA sequences (Caldwell, J.E., Waddle, J.A., Cooper, J.A., Hollands, J.A., Casella, S.J., and Casella, J.F. (1989) J. Biol. Chem. 264, 12648-12652). beta-Actinin capped the end of an actin filament as evidenced by actin assembly of myosin S1-decorated filaments and specifically its impairment of growth in the barbed direction. Thus it is concluded that highly purified beta-actinin is identical with the more recently described Cap Z, an actin barbed-end capping protein of chicken skeletal muscle.
beta-Actinin is an actin-pointed end capping protein in skeletal muscle. Casella et al. have reported that a protein isolated from muscle acetone powder by procedures similar to those used for beta-actinin purification caps the barbed end of an actin filament (J. Biol. Chem. 261, 10915-10921 (1986)). We have confirmed the above results. However, it turned out that the two proteins were identical as to subunit sizes, peptide maps, and cross-reactivities with anti-beta-actinin IgG. The binding of the two proteins to opposite ends of an actin filament remains unexplained.
