Arc/Arg3.1 regulates an endosomal pathway essential for activity-dependent β-amyloid generation.

Assemblies of β-amyloid (Aβ) peptides are pathological mediators of Alzheimer's Disease (AD) and are produced by the sequential cleavages of amyloid precursor protein (APP) by β-secretase (BACE1) and γ-secretase. The generation of Aβ is coupled to neuronal activity, but the molecular basis is unknown. Here, we report that the immediate early gene Arc is required for activity-dependent generation of Aβ.

Novel role of neuronal Ca2+ sensor-1 as a survival factor up-regulated in injured neurons.

A molecular basis of survival from neuronal injury is essential for the development of therapeutic strategy to remedy neurodegenerative disorders. In this study, we demonstrate that an EF-hand Ca2+-binding protein neuronal Ca2+ sensor-1 (NCS-1), one of the key proteins for various neuronal functions, also acts as an important survival factor. Overexpression of NCS-1 rendered cultured neurons more tolerant to cell death caused by several kinds of stressors, whereas the dominant-negative mutant (E120Q) accelerated it.

Regulation of the neuronal fate by DeltaFosB and its downstream target, galectin-1.

In mammals, the regulation of the cell fate to either proliferate, differentiate, arrest cell growth, or initiate programmed cell death is the most fundamental mechanism for maintaining normal cell function and tissue homeostasis. Under multiple signaling pathways, Jun and Fos family proteins are known to play important roles as components of an AP-1 (activator protein-1) complex, to regulate the transcription of various genes involved in cell proliferation, differentiation and programmed cell death. DeltaFosB, one of the AP-1 subunits encoded by alternatively spliced fosB mRNA, triggers one round of proliferation in quiescent rat embryo cell lines, followed by a different cell fate such as morphological alteration or delayed cell death.

[A case of brain ischemia presenting spectacular shrinking deficit in adult-onset Still's disease associated with antiphospholipid antibody syndrome].

A 63-year-old man presenting remittent fever and multiple arthralgia was diagnosed as adult-onset Still's disease (AOSD), and started with prednisolone treatment. However, he suddenly developed loss of consciousness, paresis of the right upper extremity and aphasia shortly after the treatment. We detected an increased signal of brain tissue lactate at the branch territory of left middle cerebral artery by MR spectroscopy (MRS), but no lesions by diffusion-weighted nor T2-weighted MRI, suggesting acute brain ischemia of embolic mechanism.