Project title: Integrated cancer translational research focused on the improvement of patient survival and life quality
Program title: Develop early detection platform and personalized therapeutic strategies for upper tract urothelial carcinoma
Hepatic GNMT Protects Mice from Aristolochic Acid Nephropathy by Increasing Transcription of Female-specific CYP3A44 and Decreasing NQO1
Ming-Min Chang 1,2, Chang-Ni Lin1, Cheng-Chieh Fang1, Peir-In Liang3, Wei-Ming Lee4~6, Bi-Wen Yeh5,6, Hung-Chi Cheng7, Bu-Miin Huang2, Wen-Jeng Wu1, 5, 6, 8, 9 , Yi-Ming Arthur Chen1, 9, *
張明敏 ，林長霓，方誠傑，粱佩茵，李威明，葉碧雯，鄭鴻祺，黃宏圖，吳文正， 陳宜民
1Center for Infectious Disease and Cancer Research (CICAR), Kaohsiung Medical University, Kaohsiung, Taiwan, 2Present Address: Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan, 3Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, 4 Pingtung Hospital, Ministry of Health and Welfare, Executive Yuan, Pingtung, Taiwan, 5Department of Urology, School of Medicine , Kaohsiung Medical University, Kaohsiung, Taiwan, 6 Department of Urology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, 7 Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, 8 Department of Urology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung, Taiwan, 9Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
Aristolochic acid (AA), a natural component of Aristolochia plants, is a nephrotoxic carcinogen responsible for acute kidney injury, chronic renal failure, and associated urothelial cancers. Glycine N-methyltransferase (GNMT) acts to bind environmental carcinogens, e.g. Benzo(a)pyrene and alfatoxin B1, translocate into nucleus and detoxify them in the liver. The function of nuclear GNMT is unknown. This study aims to determine the role of GNMT in AA-induced nephropathy and clarify the molecular mechanism underlying its action. We first established an experimental AA nephropathy animal model by 3-week intraperitoneal injection of AA type I (AAI) into mice. We found that AAI induced kidney injury at a lower concentration in male (2 mg/kg/day) than in female mice (5 mg/kg/day). This implies that there are gender-differences in AAI resistance. Microarray analysis and AAI treatment of human GNMT transgenic mice suggest that GNMT reduces AAI-induced kidney injury by increasing female-specific CYP3A44/CYP3A41 transcription and inhibiting NQO1 transcription. The protective effects of GNMT were absent in GNMT knockout in mice. AAI-induced nephropathy decreased in these mice after GNMT expression was induced in the liver via the adeno-associated virus type 8 (AAV8)-mediated gene transfer system. Mechanism-wise, AAI increased GNMT nuclear translocation. Chromatin immunoprecipitation (ChIP) assay results suggest that, in GNMT transgenic mice receiving a high dose of AAI (5 mg/kg/day), nuclear GNMT interacts with Nrf2 transcripts, the transcription factor for NQO1, in liver and resulting serious kidney injuries; whereas in human GNMT transgenic mice, 5 mg/kg/day AAI exposure resulted in increased interaction between GNMT and transcripts of CAR and PXR, the transcription factors for CYP3A44/CYP3A41, and mildly impaired kidneys. In summary, hepatic GNMT protects mice from AAI nephropathy by reducing Nrf2/NQO1 transcription and enhancing CAR/PXR and female-specific CYP3A44/ CYP3A41 transcription.