Publications by authors named "Kazuhito Sai"

In various epithelial tissues, the epithelial monolayer acts as a barrier. To fulfill its function, the structural integrity of the epithelium is tightly controlled. When normal epithelial cells detach from the basal substratum and delaminate into the apical lumen, the apically extruded cells undergo apoptosis, which is termed anoikis.

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Neuroinflammation is causally associated with Alzheimer's disease (AD) pathology. Reactive glia cells secrete various neurotoxic factors that impair neuronal homeostasis eventually leading to neuronal loss. Although the glial activation mechanism in AD has been relatively well studied, how it perturbs intraneuronal signaling, which ultimately leads to neuronal cell death, remains poorly understood.

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Article Synopsis
  • TAK1, or MAP3K7, is a signaling protein involved in inflammation, and its deletion in mice actually leads to increased inflammation and reactive oxygen species (ROS) levels.
  • Contrary to traditional views, this study suggests that the increase in ROS due to TAK1 inhibition is a deliberate host response to target and eliminate intracellular bacteria.
  • The research identifies a new defense mechanism where the host recognizes bacterial interference with TAK1, resulting in ROS production and cooperation between specific cell death molecules to combat bacterial growth.
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RIPK3, a key mediator of necroptosis, has been implicated in the host defense against viral infection primary in immune cells. However, gene expression analysis revealed that RIPK3 is abundantly expressed not only in immune organs but also in the gastrointestinal tract, particularly in the small intestine. We found that orally inoculated , a bacterial foodborne pathogen, efficiently spread and caused systemic infection in -deficient mice while almost no dissemination was observed in wild-type mice.

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Sustained endoplasmic reticulum (ER) stress disrupts normal cellular homeostasis and leads to the development of many types of human diseases, including metabolic disorders. TAK1 (also known as MAP3K7) is a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family and is activated by a diverse set of inflammatory stimuli. Here, we demonstrate that TAK1 regulates ER stress and metabolic signaling through modulation of lipid biogenesis.

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