O'Flaherty Cristian, Boisvert Annie, Manku Gurpreet, Culty Martine
The Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada.
Department of Surgery (Urology Division), McGill University, Montreal, QC H4A 3J1, Canada.
Antioxidants (Basel). 2019 Dec 30;9(1):32. doi: 10.3390/antiox9010032.
Peroxiredoxins (PRDXs) are antioxidant enzymes that protect cells from oxidative stress and play a role in reactive oxygen species (ROS)-mediated signaling. We reported that PRDXs are critical for human fertility by maintaining sperm viability and regulating ROS levels during capacitation. Moreover, studies on Prdx6 mice revealed the essential role of PRDX6 in the viability, motility, and fertility competence of spermatozoa. Although PRDXs are abundant in the testis and spermatozoa, their potential role at different phases of spermatogenesis and in perinatal germ cells is unknown. Here, we examined the expression and role of PRDXs in isolated rat neonatal gonocytes, the precursors of spermatogonia, including spermatogonial stem cells. Gene array, qPCR analyses showed that PRDX1, 2, 3, 5, and 6 transcripts are among the most abundant antioxidant genes in postnatal day (PND) 3 gonocytes, while immunofluorescence confirmed the expression of PRDX1, 2, and 6 proteins. The role of PRDXs in gonocyte viability was examined using PRDX inhibitors, revealing that the 2-Cys PRDXs and PRDX6 peroxidases activities are critical for gonocytes viability in basal condition, likely preventing an excessive accumulation of endogenous ROS in the cells. In contrast to its crucial role in spermatozoa, PRDX6 independent phospholipase A (iPLA) activity was not critical in gonocytes in basal conditions. However, under conditions of HO-induced oxidative stress, all these enzymatic activities were critical to maintain gonocyte viability. The inhibition of PRDXs promoted a two-fold increase in lipid peroxidation and prevented gonocyte differentiation. These results suggest that ROS are produced in neonatal gonocytes, where they are maintained by PRDXs at levels that are non-toxic and permissive for cell differentiation. These findings show that PRDXs play a major role in the antioxidant machinery of gonocytes, to maintain cell viability and allow for differentiation.
过氧化物酶(PRDXs)是一类抗氧化酶,可保护细胞免受氧化应激,并在活性氧(ROS)介导的信号传导中发挥作用。我们报道过,PRDXs通过维持精子活力和调节获能过程中的ROS水平对人类生育至关重要。此外,对Prdx6基因敲除小鼠的研究揭示了PRDX6在精子活力、运动能力和生育能力方面的重要作用。尽管PRDXs在睾丸和精子中含量丰富,但其在精子发生不同阶段以及围产期生殖细胞中的潜在作用尚不清楚。在此,我们研究了PRDXs在分离的大鼠新生期生殖母细胞(精原细胞的前体细胞,包括精原干细胞)中的表达和作用。基因芯片和定量聚合酶链反应(qPCR)分析表明,PRDX1、2、3、5和6转录本是出生后第3天生殖母细胞中最丰富的抗氧化基因之一,而免疫荧光证实了PRDX1、2和6蛋白的表达。我们使用PRDX抑制剂研究了PRDXs在生殖母细胞活力中的作用,结果表明2-半胱氨酸PRDXs和PRDX6过氧化物酶活性在基础条件下对生殖母细胞活力至关重要,可能是通过防止细胞内源性ROS的过度积累来实现的。与它在精子中的关键作用不同,PRDX6的独立磷脂酶A(iPLA)活性在基础条件下对生殖母细胞并不关键。然而,在过氧化氢(HO)诱导的氧化应激条件下,所有这些酶活性对于维持生殖母细胞活力都至关重要。抑制PRDXs会使脂质过氧化增加两倍,并阻止生殖母细胞分化。这些结果表明,新生期生殖母细胞会产生ROS,PRDXs将其维持在对细胞分化无毒且允许的水平。这些发现表明,PRDXs在生殖母细胞的抗氧化机制中发挥着重要作用,以维持细胞活力并促进分化。