Possible effects of interleukin‐6 ( IL ‐6) on reproductive performance, embryonal development, parturition, and postnatal development have been suggested based on protein/m RNA expression level of IL ‐6 in related organs, but less is known about functions of IL ‐6 signals in these areas. Following two different approaches have been employed to investigate the role of IL ‐6 signals in fertility and pre‐/postnatal development: administration of a rat anti‐mouse IL ‐6 receptor antibody, MR 16‐1, to mice as a neutralizing antibody system, and B 6.129S2‐ I l6 tm1Kopf / J ( IL ‐6 knockout [ KO ]) mice as a KO system. By intravenously dosing 50 mg/kg of MR 16‐1 every 3 days, animals in male and female fertility studies and dams in a pre‐/postnatal development study exhibited plasma MR 16‐1 concentrations much higher than the effective plasma concentration, indicating that MR 16‐1 exposure was sufficient to completely block IL ‐6 signals. The concentration of MR 16‐1 in the plasma of fetuses exceeded that in the plasma of pregnant animals, and MR 16‐1 concentration in milk was about one‐fourth of that in plasma. Both the transient IL ‐6 signal blockade by MR 16‐1, and the constitutive IL ‐6 signal inhibition using IL ‐6 KO mice in a combined fertility and pre‐/postnatal development study, revealed no biologically important effects on fertility, early embryonic development to implantation, or pre‐/postnatal development, including I g G / I g M production by keyhole limpet hemocyanin sensitization. These results indicate that IL ‐6 signals have no unique, noncompensable roles in reproduction and development in the whole body system, although contributions of IL ‐6 in the signaling network appear to exist, as suggested by previously published investigations.
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.
In this study we asked whether members of thehedgehoggene family are involved in osteogenesis. C3H10T1/2 cells and MC3T3-E1 cells expressed the putative hedgehog receptorpatched(Ptc) gene. Medium conditioned by chicken embryo fibroblast cultures expressing either Indian hedgehog or Sonic hedgehog stimulated alkaline phosphatase (APase) activity in cultures of the mouse mesenchymal cell line C3H10T1/2 and the osteoblastic cell line MC3T3-E1. These stimulatory effects were synergistically enhanced by bone morphogenetic protein-2 (BMP-2). Treatment with the amino-terminal portion of recombinant Sonic hedgehog proteins (rShh-N) up-regulated the expression of thePtcgene within 12 h and increased production of APase in C3H10T1/2. rShh-N and BMP-2 also synergistically stimulated APase activity. rShh-N treatment did not affect the expression levels ofBmp-2, -4, -5, -6and -7genes. These findings indicate that hedgehog proteins directly act on osteogenic precursor cells and osteoblasts and stimulate osteogenic differentiation of these cells in co-operation with BMPs.
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.
We assessed the change of bone mineral density (BMD) in lactating beagles with dual energy X-ray absorptiometry (DXA) and the preventive effect of 1alpha-hydroxyvitamin D3 (1alpha(OH)D3) on the BMD. Beagles, two to five years old, were used for detecting the time course change of BMD. Since the coefficient of variation (CV(%)) on detecting lumber vertebral (L2-L4) and tibial BMD by DXA was about 0.5%, DXA was useful to detect the change of BMD in beagles. There was a marked decrease in vertebral BMD during lactational period in the control group. The BMD levels after weaning were found to reverse to the initial level at mating. The same tendency was observed in tibial BMD as vertebral BMD, though the BMD changes were not marked. Beagles were administered at a dose of 0.1 microg/kg of 1alpha(OH)D3 three times in a week, and it was found to suppress the decrease in vertebral BMD during the breast feeding period. Also, the administration of 1alpha(OH)D3 promoted the prevention of decreased BMD during lactation both in vertebrae and tibiae. Significant effects of 1alpha(OH)D3 administration on tibial BMD were not observed. No adverse effects, such as hypercalcemia and hypercalciuria, were observed during the experimental period. Therefore, DXA was useful for detecting the changes of BMD in lactating beagles and the change of BMD was marked in lumber vertebrae, which are rich in trabecular bone. The preventive effect of 1alpha(OH)D3 on the decrease of BMD during the lactation period was observed in beagles.
