Research Themes

• 近赤外光活性化人工チャネルの創生による抗がん治療法の開発
  01 Apr. 2023 - 31 Mar. 2026
• 細胞種ごとに異なる発現パターンを示す小胞体内イオン輸送体の生理学的意義の解明
  01 Apr. 2020 - 31 Mar. 2025
• The development of regulatory methods for osteocyte function using optogenetics
  Grant-in-Aid for Challenging Research (Exploratory)
  29 Jun. 2018 - 31 Mar. 2023
• The development of light-activatable proteins for inducing mechanical stimulation in the cells
  Grant-in-Aid for Challenging Exploratory Research
  Tohoku University
  01 Apr. 2015 - 31 Mar. 2018
  Vertebrates have the cells which receive the mechanical force from the outer world and translate to the intracellular signaling. However, it is not clear the strength of mechanical stimulation at the local area of the cell and how the signals transduce from cell to cell because these mechanosensory cells are often embedded in the hard tissues like bone. So, we developed the non-contact method to provide mechanical stress in the specified area of the cell by using visible light. We made some light-activatable protein pairs containing LOV domain (light accepting module) and actin-depolymerizing proteins. The expressing vectors of light-activatable proteins were transfected into the MC3T3-E1 cells. The irradiation of blue light to the cells has resulted in a decrease of the actin filament. As this effect is not so remarkably, the improvement of light-activatable proteins is needed.
• Pathophysiological analysis of oral diseases caused by dysregulation of cation channels
  Grant-in-Aid for Scientific Research (C)
  Tohoku University
  01 Apr. 2015 - 31 Mar. 2018
  We studied the effects of the stimulating ingredients on TRPA1 channel recombinantly expressed in HEK293 cells using the Ca2+ imaging analysis and the patch-clamp technique. Formaldehyde, butylaldehyde, methyl ethyl ketone, and NNK (4-(methylnitrosoamino) -1-(3-pyridyl)-1-butanoe) activated TRPA1 channel, although acetone, crotonaldyhyde, isoprene, and nicotine did not induce Ca2+ transient. Acrylonitrile induced TRPA1 channel current.
  We examined the responses to the cigarette smoke elements in trigeminal ganglion neurons and human gingival fibroblast 1. TRPA1 channel was expressed in TRG neurons and HGF-1 cells. Similar to the selective TRPA1 agonist allyl isothiocyanate (AITC), the chemical substances contained in the smoke of tobacco increased intracellular Ca2+ concentration, and induced the outwardly rectifying currents. The responses were blocked by the selective TRPA1 antagonist HC-030031. Therefore it is suggested that TRPA1 channel is activated by the ingredients.
• Drug-delivery-system through ion channels
  Grant-in-Aid for Challenging Exploratory Research
  Tohoku University
  01 Apr. 2013 - 31 Mar. 2015
  TRPV1 channel is activated by capsaicin and is permeable to Na+, K+ and Ca2+. Concentration-response relationship for capsaicin was obtained from the HEK293 cells expressing recombinant TRPV1 channel. The threshold concentration and EC50 of capsaicin were 0.03 and 0.22 uM, respectively. FM1-43, a positively charged organic ion, was a permeant when the TRPV1 channel was activated by 1 uM capsaicin, indicating that TRPV1 channel pore size is wide enough to pass the 452 Da FM1-43. When the extracellular Ca2+ was removed, the FM1-43 could not enter the cells through the TRPV1 channel. These results suggest that the TRPV1 channel pore is dilated by capsaicin but extracellular Ca2+ regulates the dilation.
• Identification of mechanosensitive channels responded to hypo-osmotic stress in the osteoblast
  Grant-in-Aid for Young Scientists (B)
  Tohoku University
  2010 - 2011
  Mechanical stress plays a vital role in maintaining bone architecture. The process by which osteoblasts convert mechanical signal into biochemical responses leading to bone remodeling is not fully understood. In spite of the significant role of mechanosensitive channels in osteoblast, the molecular identity of mechanosensitive channels remains unknown. When we applied the hypo-osmotic stress in the presence of extracellular Ca^(2+), some cells were responded. But specific TRPV2 or TRPV4 siRNA could not inhibit Ca^(2+)response by hypo-osmotic stress. These results indicate that TRPV2 or TRPV4 channels are not candidate for the hypo-osmotic stress responding channel in osteoblast.
• Functional analysis of oral sensation on the basis of signalplexes
  Grant-in-Aid for Scientific Research (B)
  Tohoku University
  2009 - 2011
  Fat is one of the three major nutrients but it is not a sapid substance which activates one of the five basic tastes, sweet, bitter, sour, salt, and umami. However, we have experience that fat changes the taste of dishes largely. Transient receptor potential M5(TRPM5)channel is not a receptor of the five basic tastes but it is gated after stimulation of the gustducin-coupled receptors for sweet, bitter, and umami. We analyzed the electrophysiological and pharmacological properties of TRPM5 channel. TRPM5 channel was not activated by fatty acids, but modulated by fatty acids.
• The activation mechanisms of mechanosensitive cation channels in boneremodeling.
  Grant-in-Aid for Young Scientists (B)
  Tohoku University
  2008 - 2009
  Mechanical stress plays a vital role in maintaining bone architecture. The process by which osteoblasts convert mechanical signal into biochemical responses leading to bone remodeling is not fully understood. In spite of the significant role of channels in osteoblast, the molecular identity of mechanosensitive channels remains unknown. To identify the mechanosensitive channels, we examined the expression level of channels in the clonal mouse osteoblast cell line MC3T3-E1. RT-PCR analysis revealed some mechanosensitive channel genes are expressed in MC3T3-E1 cells.