(P23-047-23) Angiogenin-Mediated tRNA Fragmentation as a Possible Mechanism for Paternal Transmission of Diet-Induced Metabolic Dysregulation

Objectives: Offspring from diet-induced obese mice showed metabolic dysregulation phenotype despite normal diet feeding and the tRNA fragments (tRF) function as a mediator of transgenerational effects. Angiogenin (Ang) is one of ribonucleases involved in generation of tRFs. Although multiple studies have shown the increase of tRFs in germline by metabolic stress, the mechanism causing the tRNA fragmentation is still unknown. We investigated a potential molecular mechanism underlying the upstream of angiogenin-mediated tRNA fragmentation.

Methods: Total RNA- and small RNA-sequencing (smRNA seq) were conducted for testis and sperms of control diet (CD)- and high fat diet (HFD)-fed mice. HFD-induced metabolites in serum and sperms were determined by using publicly available metabolome data. Changes in expression of tRNA modifying genes were measured by qRT-PCR. For functional validation, Compound C (AMPK inhibitor, CC)-treated or non-treated TM3 and TM4 cells were further analyzed with qRT-PCR, western blots, and northern blots.

Results: SmRNA seq on sperms revealed that changes of miRNAs and tRFs were abundant in HFD group compared to CD. In particular, 3’ tRFs derived from Gly-, Lys-, and Pro-tRNA were mostly up regulated under HFD. The changes were correlated with tRNA modifying genes, tRNA methyltransferases, Dnmt2 and Nsun2 were upregulated in testis in response to HFD despite no change in methylation status. Transcriptome and metabolome analysis showed that oxidative phosphorylation-related genes in testis were significantly downregulated and the level of amino acids or their derivatives, including Lys, Thr, Tyr, Val, and 2-aminoadipate, was increased in sperm in response to HFD. Ang mRNA level was significantly increased in testis, and AMPK-mTOR pathway, a potential upstream regulator, was slightly altered by HFD. Inhibition of AMPK activity using CC led to Ang induction in testis cell lines TM3 and TM4, and subsequent increase of 3’ tRF-Pro and Val.

Conclusions: Our data suggested that metabolic stress-induced inhibition of AMPK led to Ang-mediated tRNA fragmentation, which is a key mediator of transgenerational mechanism of metabolic dysregulation.

Funding Sources: This study was supported by Basic Research Programs through the National Research Foundation (NRF) funded by the Ministry of Education.