Naoya Shimada

IRF-7 is the master regulator of type-I interferon-dependent immune responses.

The type-I interferon (IFN-α/β) response is critical to immunity against viruses and can be triggered in many cell types by cytosolic detection of viral infection, or in differentiated plasmacytoid dendritic cells by the Toll-like receptor 9 (TLR9) subfamily, which generates signals via the adaptor MyD88 to elicit robust IFN induction. Using mice deficient in the Irf7 gene (Irf7-/- mice), we show that the transcription factor IRF-7 is essential for the induction of IFN-α/β genes via the virus-activated, MyD88-independent pathway and the TLR-activated, MyD88-dependent pathway. Viral induction of MyD88-independent IFN-α/β genes is severely impaired in Irf7-/- fibroblasts. Consistently, Irf7-/- mice are more vulnerable than Myd88-/- mice to viral infection, and this correlates with a marked decrease in serum IFN levels, indicating the importance of the IRF-7-dependent induction of systemic IFN responses for innate antiviral immunity. Furthermore, robust induction of IFN production by activation of the TLR9 subfamily in plasmacytoid dendritic cells is entirely dependent on IRF-7, and this MyD88–IRF-7 pathway governs the induction of CD8+ T-cell responses. Thus, all elements of IFN responses, whether the systemic production of IFN in innate immunity or the local action of IFN from plasmacytoid dendritic cells in adaptive immunity, are under the control of IRF-7.

Nanoscale dynamic viscoelasticity analyzer by using optically driven nanobeams for study of biomolecules

We have been developing optically driven micro-robots for biosensing such as cellular mechanical properties. In this report, we have created a novel optically driven micro-robot to analyze mechanical properties of cellular proteins. The micro-robot has two parallel beams with rectangular shaped walls on the end, extending from a base block. One of the beams can be manipulated to bend to and fro. When proteins are placed between the two walls, the movement of the manipulated beam will be mechanically transferred by proteins to the other wall causing it to move. By measuring both the input and output, mechanical properties of proteins can be identified. This device becomes unique tool for cellular biology.