Shizuo Akira

Bio: Shizuo Akira is an academic researcher from Osaka University. The author has contributed to research in topics: Innate immune system & Immune system. The author has an hindex of 261, co-authored 1308 publications receiving 320561 citations. Previous affiliations of Shizuo Akira include University of California, Berkeley & Wakayama Medical University.

Myeloid Differentiation Factor-88 Plays a Crucial Role in the Pathogenesis of Coxsackievirus B3–Induced Myocarditis and Influences Type I Interferon Production

Abstract: Background—Myeloid differentiation factor (MyD)-88 is a key adaptor protein that plays a major role in the innate immune pathway. How MyD88 may regulate host response in inflammatory heart disease is unknown. Methods and Results—We found that the cardiac protein level of MyD88 was significantly increased in the hearts of wild-type mice after exposure to Coxsackievirus B3 (CVB3). MyD88 / mice showed a dramatic higher survival rate (86%) in contrast to the low survival (35%) in the MyD88 / mice after CVB3 infection (P0.0001). Pathological examination showed a significant decrease of cardiac and pancreatic inflammation in the MyD88 / mice. Viral concentrations in the hearts were significantly decreased in the MyD88 / mice. Cardiac mRNA levels for interleukin (IL)-1, tumor necrosis factor (TNF)-, interferon (IFN)-, and IL-18 were significantly decreased in the MyD88 / mice. Similarly, serum levels of T-helper 1 cytokines were significantly decreased in the MyD88 / mice. In contrast, cardiac protein levels of the activated interferon regulatory factor (IRF)-3 and IFN- were significantly increased in the MyD88 / mice but not other usual upstream signals to IRF-3. The cardiac expression of coxsackie-adenoviral receptor and p56 lck were also significantly decreased. Conclusions—MyD88 appears to be a key contributor to cardiac inflammation, mediating cytokine production and T-helper-1/2 cytokine balance, increasing coxsackie-adenoviral receptor and p56 lck expression and viral titers after CVB3 exposure. Absence of MyD88 confers host protection possibly through novel direct activation of IRF-3 and IFN-. (Circulation. 2005;112:2276-2285.)

Suppressor of cytokine signaling-1 selectively inhibits LPS-induced IL-6 production by regulating JAK-STAT.

Abstract: Suppressor of cytokine signaling-1 (SOCS-1) is one of the negative-feedback regulators of Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling. We previously showed that SOCS-1 participates in LPS signaling, but it is not entirely clear yet how SOCS-1 suppresses LPS signaling. In this study, we demonstrate that SOCS-1 selectively inhibits LPS-induced IL-6 production through regulation of JAK-STAT but not production of TNF-alpha, granulocyte colony-stimulating factor, IFN-beta, and other cytokines. We found that LPS directly activated Jak2 and Stat5, whereas SOCS-1 inhibited LPS-induced Jak2 and Stat5 activation. Furthermore, AG490, a Jak-specific inhibitor, and dominant negative Stat5 only reduced LPS-induced IL-6 production. Additionally, Stat5 interacted with p50, resulting in recruitment of Stat5 to the IL-6 promoter together with p50 in response to LPS stimulation. These findings suggest that the JAK-STAT pathway participates in LPS-induced IL-6 production and that SOCS-1 suppresses LPS signaling by regulating JAK-STAT.

Natural killer cell and macrophage cooperation in MyD88-dependent innate responses to Plasmodium falciparum

Abstract: IFN-γ secretion by natural killer (NK) cells is pivotal to several tumor and viral immune responses, during which NK and dendritic cells cooperation is required. We show here that macrophages are mandatory for NK cell IFN-γ secretion in response to erythrocytes infected with Plasmodium falciparum (Pf), a causative agent of human malaria. In addition, direct sensing of Pf infection by NK cells induces their production of the proinflammatory chemokine CXCL8, without triggering their granule-mediated cytolytic programs. Despite their reported role in Pf recognition, Toll-like receptor (TLR) 2, TLR9, and TLR11 are individually dispensable for NK cell activation induced by Pf-infected erythrocytes. However, IL-18R expression on NK cells, IL-18 production by macrophages, and MyD88 on both cell types are essential components of this previously undescribed pathway of NK cell activation in response to a parasite infection.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine.

Abstract: Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the resulting coronavirus disease 2019 (Covid-19) have afflicted tens of millions of people in a world...

Cancer-related inflammation.

Abstract: The mediators and cellular effectors of inflammation are important constituents of the local environment of tumours. In some types of cancer, inflammatory conditions are present before a malignant change occurs. Conversely, in other types of cancer, an oncogenic change induces an inflammatory microenvironment that promotes the development of tumours. Regardless of its origin, 'smouldering' inflammation in the tumour microenvironment has many tumour-promoting effects. It aids in the proliferation and survival of malignant cells, promotes angiogenesis and metastasis, subverts adaptive immune responses, and alters responses to hormones and chemotherapeutic agents. The molecular pathways of this cancer-related inflammation are now being unravelled, resulting in the identification of new target molecules that could lead to improved diagnosis and treatment.