Transcriptomic and epigenomic profiling of young and aged spermatogonial stem cells reveals molecular targets regulating differentiation

• Published in: PLoS genetics 2021-07, Vol.17 (7), p.e1009369-e1009369
• Main Authors: Liao, Jinyue, Suen, Hoi Ching, Luk, Alfred Chun Shui, Yang, Lele, Lee, Annie Wing Tung, Qi, Huayu, Lee, Tin-Lap
• Format: Article
• Language: English
• Subjects: 5-Methylcytosine - metabolism; Adult Germline Stem Cells - cytology; Adult Germline Stem Cells - physiology; Age; Aging; Aging - genetics; Aging - physiology; Alternative Splicing; Animals; Biology and Life Sciences; Cell Differentiation; Cell self-renewal; Epigenetic inheritance; Epigenetics; Epigenome; Fertility; Gene expression; Gene Expression Profiling; Gene Expression Regulation; Genetic aspects; Genomes; Genomic analysis; Health aspects; Infertility; Lysine - genetics; Lysine - metabolism; Male; Meiosis; Mice; Mice, Inbred C57BL; Mice, Transgenic; Non-coding RNA; Oct-4 protein; Ontology; Oxidative stress; Progenitor cells; RNA; RNA, Long Noncoding - genetics; Spermatogenesis; Spermatogonia; Spermatozoa; Stem cell transplantation; Stem cells; Testis - cytology; Transcriptomes; Wnt protein
• ISSN: 1553-7404; 1553-7390; 1553-7404
• DOI: 10.1371/journal.pgen.1009369

Spermatogonial stem cells (SSC), the foundation of spermatogenesis and male fertility, possess lifelong self-renewal activity. Aging leads to the decline in stem cell function and increased risk of paternal age-related genetic diseases. In the present study, we performed a comparative genomic analysis of mouse SSC-enriched undifferentiated spermatogonia (Oct4-GFP+/KIT-) and differentiating progenitors (Oct4-GFP+/KIT+) isolated from young and aged testes. Our transcriptome data revealed enormous complexity of expressed coding and non-coding RNAs and alternative splicing regulation during SSC differentiation. Further comparison between young and aged undifferentiated spermatogonia suggested these differentiation programs were affected by aging. We identified aberrant expression of genes associated with meiosis and TGF-β signaling, alteration in alternative splicing regulation and differential expression of specific lncRNAs such as Fendrr. Epigenetic profiling revealed reduced H3K27me3 deposition at numerous pro-differentiation genes during SSC differentiation as well as aberrant H3K27me3 distribution at genes in Wnt and TGF-β signaling upon aging. Finally, aged undifferentiated spermatogonia exhibited gene body hypomethylation, which is accompanied by an elevated 5hmC level. We believe this in-depth molecular analysis will serve as a reference for future analysis of SSC aging.