Oct4 reduction contributes to testicular injury of unilateral testicular torsion in mice model and apoptotic death of Sertoli cells through mediating CIP2A expression.

This study explored the mechanism of ipsilateral testis injury after ipsilateral testicular torsion detorsion (T/D) and the potential testis-protective part of the octamer-binding transcription factor 4 (Oct4)-cancerous inhibitors of protein phosphatase 2A (CIP2A) axis in a T/D animal model and in ischemia-reperfusion (IR)-treated testicular Sertoli TM4 cells. Quantitative Polymerase chain reaction (PCR) and western blot (WB) confirmed the downregulation of both CIP2A and Oct4 expression in the testicular tissue from T/D mice compared with sham-operated mice. T/D model was then established in mice with upregulated Oct4 expression in the testis. Oct4 elevation restored CIP2A expression in testes after T/D treatment. Furthermore, we observed that an increase in Oct4 ameliorated the testicular damage caused by torsion in the testis. Biochemical analysis indicated that T/D treatment increased serum anti-sperm antibody levels, but reduced testosterone levels. Meanwhile, in testicular tissue, reactive oxygen species (ROS), malondialdehyde (MDA), and activity of testicular myeloperoxidase (MPO) enzymes were promoted, while glutathione peroxidase activity (GPx) was decreased by T/D injury. Notably, testicular Oct4 restoration partially counteracted the effect of T/D treatment on these biochemical indices. Hypoxia/reoxygenation (HR) treatment was applied to TM4 cells to mimic TT injury in vitro. A gain-of-function study showed that Oct4 overexpression partly counteracted the promoting role of HR in cell damage, apoptosis, and oxidative stress in TM4 cells. These observations provide novel insights into the possible biochemical mechanism underlying the mediation of the Oct4-CIP2A axis in T/D injury.

OCT4 Represses Inflammation and Cell Injury During Orchitis by Regulating CIP2A Expression.

Octamer-binding transcription factor 4 (OCT4) and cancerous inhibitor of protein phosphatase 2A (CIP2A) are upregulated in testicular cancer and cell lines. However, its contribution to orchitis (testicular inflammation) is unclear and was thus, investigated herein. Cell-based experiments on a lipopolysaccharide (LPS)-induced orchitis mouse model revealed robust inflammation, apoptotic cell death, and redox disorder in the Leydig (interstitial), Sertoli (supporting), and, germ cells. Meanwhile, real-time quantitative PCR revealed low OCT4 and CIP2A levels in testicular tissue and LPS-stimulated cells. A gain-of-function study showed that OCT4 overexpression not only increased CIP2A expression but also repressed LPS-induced inflammation, apoptosis, and redox disorder in the aforementioned cells. Furthermore, the re-inhibition of CIP2A expression by TD-19 in OCT4-overexpressing cells counteracted the effects of OCT4 overexpression on inflammation, apoptosis, and redox equilibrium. In addition, our results indicated that the Keap1-Nrf2-HO-1 signaling pathway was mediated by OCT4 and CIP2A. These findings provide insights into the potential mechanism underlying OCT4- and CIP2A-mediated testicular inflammation.