The food supply system is facing important challenges and its sustainability has to be considered. Genome-editing technology, which accelerates the development of new variety, could be used to achieve sustainable development goals, thereby protecting the environment and ensuring the stable production of food for an increasing global population. The most widely used genome-editing tool, CRISPR/Cas9, is easy to use, affordable, and versatile. Foods produced by genome-editing technologies have been developed worldwide to create novel traits. In the first half of the review, the latest scientific findings on genome-editing technologies are summarized, and the technical challenge in genome sequence analysis are clarified. CRISPR/Cas9 has versatile alternative techniques, such as base editor and prime editor. Genome sequencing technology has developed rapidly in recent years. However, it is still difficult to detect large deletions and structural variations. Long-read sequencing technology would solve this challenge. In the second part, regulatory framework and approach for genome-edited foods is introduced. The four government ministries, including the Ministry of Environment, the Ministry of Agriculture, Forestry and Fisheries, and the Ministry of Health, Labour and Welfare (MHLW), started to discuss how the regulation should be implemented in 2019. The SDN-1 technique is excluded from the current genetically modified organism (GMO) regulation. The Japanese regulatory framework includes pre-submission consultation and submission of notification form. In the last part of this review, transparency of regulatory framework and consumer confidence were described. Since maintaining consumer trust is vital, transparency of regulatory framework is a key to consumers. The information of notification process on approved genome-edited foods is made public immediately. This review will help regulators build regulatory frameworks, and lead to harmonization of the framework between the countries.

Cytochrome P450 (CYP)-mediated metabolisms of four chemicals have been investigated to understand their unresolved phenomena of their metabolisms using human CYP-Template systems developed in our previous studies (Drug Metab Pharmacokinet 2019, 2021, 2022). Simulation experiments of a topoisomerase-targeting agent, amonafide, offered a possible new inhibitory-mechanism as Trigger-residue inactivation on human CYP1A2 Template. N-Acetylamonafide as well as amonafide would inactivate CYP1A2 through the interference of Trigger-residue movement with their dimethylaminoethyl parts. The mechanism was also supported on the inhibition/inactivation of two other drugs, DSP-1053 and binimetinib. Both the drugs, after other CYP-mediated slight structural alterations, were expected to interact with Trigger-residue for the intense inhibition on CYP1A2 Template. Possible formation of reactive intermediates of amonafide and 3-methylindole was also examined on CYP1A2 Template. Placements of amonafide suggested the scare N-oxidation of the arylamine part due to the Trigger-residue interaction. Placements of 3-methylindole suggested the formation of a reactive intermediate, 3-methyleneindolenine, rather selectively on rodent CYP1A2 than on human CYP1A2, in consistent with the experimental data. These results suggest that CYP Template systems developed are effective tools to warn an appearance of unstable reactive intermediates. Our CYP-Template systems would support confident judgements in safety assessments through offering the mechanistic understandings of the metabolism.

Food Safety Commission of Japan (FSCJ) conducted a risk assessment of a bipyridinium herbicide, paraquat (CAS No. 1910-42-5), based on results from various studies. Major adverse effects of paraquat in experimental animals were observed in body weight (suppressed weight gain), lungs (increased weight, alveolar epithelium hyperplasia, and pneumonia), kidneys (renal tubule dilatation) and eyes (cataract in rats and dogs). The effects on the lung were considered to be the most critical endpoints in the assessment. Neither carcinogenicity, effects on fertility, teratogenicity, genotoxicity, or immunotoxicity was observed. FSCJ reasonably concluded no obvious concern of paraquat-residue in foods to yield neurotoxicity through human dietary exposure, as long as paraquat is applied following the registered standard use of the pesticide. The lowest no-observed-adverse-effect level (NOAEL) obtained from all the studies was 0.45 mg paraquat ion^*/kg bw per day in one-year chronic toxicity study in dogs. FSCJ specified an acceptable daily intake (ADI) of 0.0045 mg paraquat ion/kg bw per day by applying a safety factor of 100 to the NOAEL. FSCJ judged these effects also as the end-point of the acute reference dose (ARfD). The lowest NOAEL was 0.45 mg paraquat ion/kg bw per day in one-year chronic toxicity study in dogs. For potential adverse effects of a single oral administration of paraquat, FSCJ specified an ARfD to be 0.0045 mg paraquat ion/kg bw by applying a safety factor of 100 to the NOAEL.