Transcriptome Studies Reveal the N6-Methyladenosine Differences in Testis of Yaks at Juvenile and Sexual Maturity Stages

Studying the mechanism of spermatogenesis is key to exploring the reproductive characteristics of male yaks. Although N6-methyladenosine (m6A) RNA modification has been reported to regulate spermatogenesis and reproductive function in mammals, the molecular mechanism of m6A in yak testis development and spermatogenesis remains largely unknown. Therefore, we collected testicular tissue from juvenile and adult yaks and found that the m6A level significantly increased after sexual maturity in yaks. In MeRIP-seq, 1702 hypermethylated peaks and 724 hypomethylated peaks were identified. The hypermethylated differentially methylated RNAs (DMRs) (CIB2, AK1, FOXJ2, PKDREJ, SLC9A3, and TOPAZ1) mainly regulated spermatogenesis. Functional enrichment analysis showed that DMRs were significantly enriched in the adherens junction, gap junction, and Wnt, PI3K, and mTOR signaling pathways, regulating cell development, spermatogenesis, and testicular endocrine function. The functional analysis of differentially expressed genes showed that they were involved in the biological processes of mitosis, meiosis, and flagellated sperm motility during the sexual maturity of yak testis. We also screened the key regulatory factors of testis development and spermatogenesis by combined analysis, which included BRCA1, CREBBP, STAT3, and SMAD4. This study indexed the m6A characteristics of yak testicles at different developmental stages, providing basic data for further research of m6A modification regulating yak testicular development.

[Clinical effects of free perforator propeller myocutaneous flap from buttock in repairing complex wounds in the buttock with deep dead cavity]

Objective: To investigate the feasibility and clinical effects of using free perforator propeller myocutaneous flap from buttock in repairing complex wounds in the buttock with deep dead cavity. Methods: A retrospective observational study was conducted. From June 2020 to June 2022, 9 patients with complex wounds in the buttock with deep dead cavity who met the inclusion criteria were admitted to Lanzhou University Second Hospital, including 6 males and 3 females, aged 26 to 62 years, with original wound area ranging from 4.0 cm×3.0 cm to 8.0 cm×7.0 cm and dead cavity depth of 7 to 11 cm. All the wounds were repaired with free perforator propeller myocutaneous flap from buttock, with flap area of 6.0 cm×2.5 cm to 13.0 cm×7.0 cm and muscle flap length of 6 to 11 cm. All the wounds in the donor area were closed and sutured directly. Postoperative myocutaneous flap survival, complications, as well as donor and recipient wound healing were observed, and the shape of donor and recipient areas were followed up. Results: Congestion occurred under the myocutaneous flap of one patient due to poor drainage on post surgery day 2, which was healed after 15 days of drainage and dressing change. The myocutaneous flaps of other patients survived successfully after surgery. The wounds in the donor and recipient areas were all well healed. During the follow-up of 3 to 10 months, the donor and recipient areas were full in shape, with little difference from the healthy side, and were able to bear pressure. Conclusions: The free perforator propeller myocutaneous flap from buttock can repair the deep dead cavity and surface wounds at the same time. The use of this myocutaneous flap in repairing complex wounds in the buttock with deep dead cavity results in minimal damage to the donor area, allows pressure-bearing of the donor and recipient areas after surgery, and ensures a full buttock shape.

Single-Cell RNA Sequencing Reveals Atlas of Yak Testis Cells

Spermatogenesis is a complex process that involves proliferation and differentiation of diploid male germ cells into haploid flagellated sperm and requires intricate interactions between testicular somatic cells and germ cells. The cellular heterogeneity of this process presents a challenge in analyzing the different cell types at various developmental stages. Single-cell RNA sequencing (scRNA-seq) provides a useful tool for exploring cellular heterogeneity. In this study, we performed a comprehensive and unbiased single-cell transcriptomic study of spermatogenesis in sexually mature 4-year-old yak using 10× Genomics scRNA-seq. Our scRNA-seq analysis identified six somatic cell types and various germ cells, including spermatogonial stem cells, spermatogonia, early-spermatocytes, late-spermatocytes, and spermatids in yak testis. Pseudo-timing analysis showed that Leydig and myoid cells originated from common progenitor cells in yaks. Moreover, functional enrichment analysis demonstrated that the top expressed genes in yak testicular somatic cells were significantly enriched in the cAMP signaling pathway, PI3K-Akt signaling pathway, MAPK signaling pathway, and ECM receptor interactions. Throughout the spermatogenesis process, genes related to spermatogenesis, cell differentiation, DNA binding, and ATP binding were expressed. Using immunohistochemical techniques, we identified candidate marker genes for spermatogonial stem cells and Sertoli cells. Our research provides new insights into yak spermatogenesis and the development of various types of cells in the testis, and presents more reliable marker proteins for in vitro culture and identification of yak spermatogonial stem cells in the later stage.