lncRNA involved in triptonide-induced cytotoxicity in mouse germ cells

Triptonide reportedly has strong antitumor and anti-inflammatory activities. However, its severe toxicity, including to the reproductive system, has greatly restricted its use in patients who wish to preserve fertility. lncRNAs play crucial roles in male fertility and reportedly regulate triptonide's antitumor activity. However, whether lncRNAs are involved in triptonide-induced reproductive toxicity is unknown. Here, we showed that triptonide induced significant cytotoxicity, as demonstrated by reduced cell viability and induction of apoptosis and autophagy in mouse germ cells (a spermatocyte cell line, GC2). The expression levels of numerous lncRNAs and mRNAs in GC2 cells were altered at the transcriptome level after treatment with triptonide for 24 h, as determined by RNA sequencing. Gene ontology and pathway analyses showed that the functions of the differentially expressed lncRNAs and mRNAs were closely linked with many processes, including gene expression regulation, cell death, cell cycle regulation, cell proliferation and development and others. After validating our RNA-seq data, we selected one lncRNA, Obox4-ps35, dramatically induced by triptonide for further investigation. Obox4-ps35 knock-out aggravated triptonide-induced cytotoxicity by decreasing cell survival and increasing apoptosis and autophagy rates. These data suggest that germ cells exposed to triptonide overexpress Obox4-ps35 to protect against triptonide-induced cytotoxicity. This study provides preliminary evidence and novel directions for exploring roles of lncRNAs in triptonide-induced cytotoxicity, especially in reproductive toxicity.