Jiyeon Ham a,1, Wonhyoung Park b,1, Jisoo Song c,1, Hee Seung Kim d, Gwonhwa Song b, Whasun Lim c, Soo Jin Park d, Sunwoo Park e
aDivision of Animal and Dairy Science, Chungnam National University, Daejeon 34134, Republic of Korea
bInstitute of Animal Molecular Biotechnology and Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
cDepartment of Biological Sciences, College of Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
dDepartment of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
eDepartment of Plant & Biomaterials Science, Gyeongsang National University, Junju-si 52725, Republic of Korea
1These authors contributed equally to this work.
Corresponding authors : Whasun Lim, Soo Jin Park, Sunwoo Park
Background: Fraxetin, a phytochemical obtained from Fraxinus rhynchophylla, is well known for its anti-inflammatory and anti-fibrotic properties. However, fraxetin regulates the progression of endometriosis, which is a benign reproductive disease that results in low quality of life and infertility.
Hypothesis/purpose: We hypothesized that fraxetin may have therapeutic effects on endometriosis and aimed to elucidate the underlying mechanisms of mitochondrial function and tiRNA regulation.
Study design: Endometriotic animal models and cells (End1/E6E7 and VK2/E6E7) were used to identify the mode of action of fraxetin.
Methods: An auto-implanted endometriosis animal model was established and the effects of fraxetin on lesion size reduction were analyzed. Cell-based assays including proliferation, cell cycle, migration, apoptosis, mitochondrial function, calcium efflux, and reactive oxygen species (ROS) were performed. Moreover, fraxetin signal transduction was demonstrated by western blotting and qPCR analyses.
Results: Fraxetin inhibited proliferation and migration by inactivating the P38/JNK/ERK mitogen-activated protein kinase (MAPK) and AKT/S6 pathways. Fraxetin dissipates mitochondrial membrane potential, downregulates oxidative phosphorylation (OXPHOS), and disrupts redox and calcium homeostasis. Moreover, it triggered endoplasmic reticulum stress and intrinsic apoptosis. Furthermore, we elucidated the functional role of tiRNAHisGTG in endometriosis by transfection with its inhibitor. Finally, we established an endometriosis mouse model and verified endometriotic lesion regression and downregulation of adhesion molecules with inflammation.
Conclusion: This study suggests that fraxetin is a novel therapeutic agent that targets mitochondria and tiRNAs. This is the first study to demonstrate the mechanisms of tiRNAHisGTG with mitochondrial function and cell fates and can be applied as a non-hormonal method against the progression of endometriosis.