title: A metal carbonyl-protein needle composite designed for intracellular CO delivery to modulate NF-κB activity.
abstract: Carbon monoxide (CO) has been recognized as a messenger for signal transduction in living cells and tissues. For intracellular CO delivery, several metal carbonyl complexes have been used as CO-releasing molecules (CO-RMs). To improve the properties of CO-RMs, such as the stability and the CO release rate, ligands and carriers of the metal complexes have been exploited. Here we report the development of an efficient intracellular CO delivery system using a protein scaffold. We used a protein needle reconstructed from gene product 5 of bacteriophage T4, which has high cellular permeability and stability. When ruthenium carbonyl complexes are conjugated to the needle using a His-tag triad at the C-terminus, the resulting composite has a significantly higher cellular uptake efficiency of Ru carbonyl and a 12-fold prolonged CO release rate relative to Ru(CO)3Cl(glycinate), a widely used CO-RM. We demonstrate that CO delivered by the composite activates the transcriptional factor nuclear factor-kappaB (NF-κB), which in turn leads to significant induction of expression of its target genes, HO1, NQO1, and IL6, through generation of reactive oxygen species (ROS). The signaling pathway is distinct from that of tumor necrosis factor (TNF)-α-induced activation of NF-κB. The protein needle-based CO-RM can be exploited to elucidate the biological functions of CO and used in the development of protein-based organometallic tools for modulation of cellular signaling.
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inaba
authors.forename: Nusrat J M
authors.initials: NJ
authors.lastname: Sanghamitra
authors.forename: Kenta
authors.initials: K
authors.lastname: Fujita
authors.forename: Takeya
authors.initials: T
authors.lastname: Sho
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kuchimaru
authors.forename: Susumu
authors.initials: S
authors.lastname: Kitagawa
authors.forename: Shinae
authors.initials: S
authors.lastname: Kizaka-Kondoh
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ueno
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism*; D002417:Cattle; D016503:Drug Delivery Systems; D004705:Endocytosis; D057809:HEK293 Cells; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D009339:Needles; D017433:Protein Structure, Secondary; D012428:Ruthenium / Q000737:chemistry*; D015398:Signal Transduction; D014764:Viral Proteins / Q000737:chemistry*
chemical_list: D016328:NF-kappa B; D014764:Viral Proteins; C068293:gene 5 protein, Enterobacteria phage T4; D002248:Carbon Monoxide; D012428:Ruthenium