Akimichi Morita
Nagoya City University
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Featured researches published by Akimichi Morita.
Archives of Dermatological Research | 2000
Lei Yin; Akimichi Morita; T. Tsuji
Abstract Epidemiologic studies have indicated the association between tobacco smoking and skin aging, but the exact mechanism of tobacco smoke-induced premature skin aging is currently unknown. In this study, we investigated the alterations of collagen, matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human fibroblasts treated with tobacco smoke extract. Human fibroblasts were exposed to different concentrations of water-soluble extract from tobacco smoke. Human fibroblasts irradiated with ultraviolet A1 (UVA1) were used as positive controls because the mechanism of UVA1-mediated MMP expression has been well characterized. The expression of MMP and TIMP was analyzed semiquantitatively following reverse transcriptase-polymerase chain reaction. Production of type I and type III collagens was detected by Western blotting and biosynthesis of new collagen was assessed by 3 H-proline incorporation. Upon treatment with tobacco smoke extract or UVA1 irradiation, the expression of MMP-1 and MMP-3 mRNA was significantly increased in a dose-dependent manner. Maximum induction was observed with 25 μl/ml tobacco smoke extract. In contrast, the expression of TIMP-1 and TIMP-3 mRNA remained unchanged. Western blotting of the supernatant revealed that type I and type III collagens were decreased as compared with untreated controls. Collagen biosynthesis was significantly reduced by 40.1% following treatment with ¶25 μl/ml tobacco smoke extract. Sodium azide, l -ascorbic acid and Trolox (a water-soluble vitamin E) prevented both the UVA1- and the tobacco-induced alteration of MMP-1. These observations suggest that the imbalance of connective tissue matrix components might contribute to the molecular basis for premature skin aging in smokers. They also suggest that reactive oxygen species including singlet oxygen mediate this process.
Photodermatology, Photoimmunology and Photomedicine | 2001
Lei Yin; Akimichi Morita; Takuo Tsuji
Background: Tobacco smoking, similar to ultraviolet (UV) A radiation exposure, has previously been identified as an important factor contributing to premature aging of human skin.
Journal of Investigative Dermatology | 2013
Kazumitsu Sugiura; Michiya Yamaguchi; Hidetoshi Takahashi; Yukiko Shoda; Teruyuki Mitsuma; Kenshiro Tsuda; Emi Nishida; Yaei Togawa; Kimiko Nakajima; Akihiro Sakakibara; Shigeo Kawachi; Makoto Shimizu; Yasutomo Ito; Takuya Takeichi; Michihiro Kono; Yasushi Ogawa; Yoshinao Muro; Akemi Ishida-Yamamoto; Shigetoshi Sano; Hiroyuki Matsue; Akimichi Morita; Hitoshi Mizutani; Hajime Iizuka; Masahiko Muto; Masashi Akiyama
Generalized pustular psoriasis (GPP) is a rare inflammatory skin disease that can be life-threatening. Recently, it has been reported that familial GPP is caused by homozygous or compound heterozygous mutations of IL36RN. However, the majority of GPP cases are sporadic and it is controversial whether IL36RN mutations are a causative/predisposing factor for sporadic GPP. We searched for IL36RN mutations in two groups of GPP patients in the Japanese population in this study: GPP without psoriasis vulgaris (PV), and GPP with PV. Eleven cases of GPP without PV (GPP alone) and 20 cases of GPP accompanied by PV (GPP with PV) were analyzed. Surprisingly, 9 out of 11 cases of GPP alone had homozygous or compound heterozygous mutations in IL36RN. In contrast, only 2 of 20 cases of GPP with PV had compound heterozygous mutations in IL36RN. The two cases of GPP with PV who had compound heterozygous mutations in IL36RN are siblings, and both cases had PV-susceptible HLA-A*0206. We determined that GPP alone is a distinct subtype of GPP and is etiologically distinguished from GPP with PV, and that the majority of GPP alone is caused by deficiency of the interleukin-36 receptor antagonist due to IL36RN mutations.
Nature Biotechnology | 2002
Tadashi Kumamoto; Eric K. Huang; Hyun Joon Paek; Akimichi Morita; Hiroyuki Matsue; Robert F. Valentini; Akira Takashima
Although anti-tumor immunity is inducible by dendritic cell (DC)–based vaccines, time- and cost-consuming “customizing” processes required for ex vivo DC manipulation have hindered broader clinical applications of this concept. Epidermal Langerhans cells (LCs) migrate to draining lymph nodes and undergo maturational changes on exposure to reactive haptens. We entrapped these migratory LCs by subcutaneous implantation of ethylene–vinyl–acetate (EVA) polymer rods releasing macrophage inflammatory protein (MIP)-3β (to create an artificial gradient of an LC-attracting chemokine) and topical application of hapten (to trigger LC emigration from epidermis). The entrapped LCs were antigen-loaded in situ by co-implantation of the second EVA rods releasing tumor-associated antigens (TAAs). Potent cytotoxic T-lymphocyte (CTL) activities and protective immunity against tumors were induced efficiently with each of three tested TAA preparations. Thus, tumor-specific immunity is inducible by the combination of LC entrapment and in situ LC loading technologies. Our new vaccine strategy requires no ex vivo DC manipulation and thus may provide time and cost savings.
Journal of Investigative Dermatology | 2012
Jean Krutmann; Akimichi Morita; Jin Ho Chung
The health consequences of sun exposure have concerned mankind for more than 100 years. Recent molecular studies in photodermatology have greatly advanced our understanding of this important topic. We will illustrate this progress by focusing on the following selected topics: (i) the nature of the DNA damage-independent part of the UVB response of human skin and the role of the arylhydrocarbon receptor in cutaneous biology, (ii) the contribution of wavelengths beyond the UV spectrum to solar radiation-induced skin damage, (iii) the emerging evidence that subcutaneous fat is a target tissue for sunlight, and (iv) the most recent insight into the mode of action of phototherapy.
Journal of The American Academy of Dermatology | 2015
Ulrich Mrowietz; Craig L. Leonardi; Giampiero Girolomoni; Darryl Toth; Akimichi Morita; Shyamal A. Balki; Jacek C. Szepietowski; Pascaline Regnault; Helen Thurston; Charis Papavassilis
BACKGROUND Secukinumab has demonstrated high, sustained efficacy in psoriasis to 52 weeks on a fixed-interval regimen. OBJECTIVE We sought to compare a retreatment-as-needed versus a fixed-interval regimen. METHODS In this double-blind study, adults with moderate to severe plaque psoriasis were randomized 1:1 to subcutaneous secukinumab at 300 mg (n = 484) or 150 mg (n = 482) weekly from baseline until week 4, and at week 8. At week 12, patients achieving 75% or more improvement from baseline Psoriasis Area and Severity Index score (PASI 75) were rerandomized to 2 dose levels of secukinumab retreatment as needed (n = 217, 300 mg; n = 206, 150 mg) or fixed interval (n = 217; n = 203). Primary end point was noninferiority of retreatment as needed versus fixed interval for maintaining PASI 75 to week 52. RESULTS Secukinumab induced high responses by week 12 (84.4%-91.1% PASI 75 responders). From week 12 to week 52, more patients on fixed interval (78.2%, 300 mg; 62.1%, 150 mg) maintained PASI 75 versus retreatment as needed (67.7%; 52.4%); statistical noninferiority of retreatment as needed was not established. Overall safety, including very low incidences of treatment-emergent anti-drug antibodies (<0.5%), was similar between regimens. LIMITATIONS The primary end point was developed without any known precedent. CONCLUSION Secukinumab fixed interval showed clear benefit versus the study-specified retreatment-as-needed regimen for maintaining efficacy. Both regimens exhibited safety consistent with previous trials. The potential of retreatment as needed with secukinumab warrants further investigation.
Cancer Science | 2013
Takashi Ishida; Asahi Ito; Fumihiko Sato; Shigeru Kusumoto; Shinsuke Iida; Hiroshi Inagaki; Akimichi Morita; Shiro Akinaga; Ryuzo Ueda
We report an adult T‐cell leukemia/lymphoma patient suffering from Stevens–Johnson Syndrome (SJS) during mogamulizumab (humanized anti‐CCR4 monoclonal antibody) treatment. There was a durable significant reduction of the CD4+CD25highFOXP3+ regulatory T (Treg) cell subset in the patients PBMC, and the affected inflamed skin almost completely lacked FOXP3‐positive cells. This implies an association between reduction of the Treg subset by mogamulizimab and occurrence of SJS. The present case should contribute not only to our understanding of human pathology resulting from therapeutic depletion of Treg cells, but also alert us to the possibility of immune‐related severe adverse events such as SJS when using mogamulizumab. We are currently conducting a clinical trial of mogamulizumab for CCR4‐negative solid cancers (UMIN000010050), specifically aiming to deplete Treg cells.
Journal of Immunology | 2008
Akira Maeda; Agatha Schwarz; Ann Bullinger; Akimichi Morita; David Peritt; T. Schwarz
Extracorporeal photopheresis (ECP) is used to treat immune-mediated diseases including transplant rejection and graft-vs-host-disease. An experimental murine model of ECP utilizing contact hypersensitivity (CHS) revealed that ECP inhibits the sensitization of CHS and induces regulatory T cells (Treg). In this study, we find that ECP inhibits not only the sensitization but also the effector phase of CHS, although Treg only inhibited sensitization. IL-10 was determined to be a critical component of the effector phase inhibition and also a driving force in developing Treg. Thus, we propose that the inhibition of the effector phase of CHS by ECP is a process that does not require Treg but may be mediated via enhanced IL-10 as suggested by the use of IL-10-deficient mice. This suggests that ECP has at least two mechanisms of action, one inhibiting the effector phase of CHS and one generating Treg, which in turn can inhibit CHS sensitization and is responsible for the transferable protection. Together, this may help explain the clinical benefits of ECP in prophylactic, acute, and therapeutic settings.
The journal of investigative dermatology. Symposium proceedings / the Society for Investigative Dermatology, Inc. [and] European Society for Dermatological Research | 2009
Akimichi Morita; Kan Torii; Akira Maeda; Yuji Yamaguchi
Although it is now widely recognized that tobacco smoke has negative effects on the skin, the molecular mechanisms underlying its skin-aging effects remain uncertain. Epidemiological studies indicate that tobacco smoking is a strong independent predictor of facial wrinkle formation and other aspects of premature skin aging. Recent in vivo studies in humans and mice provided the first direct evidence that tobacco smoke causes premature skin aging, and they have begun to reveal the molecular changes in the skin that occur in response to it. Water-soluble tobacco smoke extract, which predominantly produces oxidative stress when applied topically to cultured skin fibroblasts, impairs collagen biosynthesis. Matrix metalloproteinases, which degrade collagen, are induced dose-dependently by tobacco smoke extract as well as by other constituents that trigger the aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor that mediates the toxicity of several environmental contaminants, including photoproducts in the body generated by UVB radiation. Tobacco smoke also contains many non-water-soluble constituents that activate the AhR pathway. Our most recent studies using hexane-soluble tobacco extract indicate that activation of the AhR pathway may play a role in the premature skin-aging effects of tobacco smoke exposure.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 53-55; doi:10.1038/jidsymp.2009.13.
Molecular Cell | 2014
Yoshikazu Johmura; Midori Shimada; Toshinori Misaki; Aya Naiki-Ito; Hiroyuki Miyoshi; Noboru Motoyama; Naoko Ohtani; Eiji Hara; Motoki Nakamura; Akimichi Morita; Satoru Takahashi; Makoto Nakanishi
Senescence is a state of permanent growth arrest and is a pivotal part of the antitumorigenic barrier in vivo. Although the tumor suppressor activities of p53 and pRb family proteins are essential for the induction of senescence, molecular mechanisms by which these proteins induce senescence are still not clear. Using time-lapse live-cell imaging, we demonstrate here that normal human diploid fibroblasts (HDFs) exposed to various senescence-inducing stimuli undergo a mitosis skip before entry into permanent cell-cycle arrest. This mitosis skip is mediated by both p53-dependent premature activation of APC/C(Cdh1) and pRb family protein-dependent transcriptional suppression of mitotic regulators. Importantly, mitotic skipping is necessary and sufficient for senescence induction. p16 is only required for maintenance of senescence. Analysis of human nevi also suggested the role of mitosis skip in in vivo senescence. Our findings provide decisive evidence for the molecular basis underlying the induction and maintenance of cellular senescence.