Evaluation of the relationship between Ying Yang 1 (YY1) and Raf Kinase Inhibitor Protein (RKIP) in azoospermia patients with maturation arrest

Project no. 32441 · Status: Kapanmış (Yayın bekleniyor) · 2024

Summary

Spermatogenesis is a tightly regulated, multi-step biological process occurring in the seminiferous tubules of the testis, involving the transformation of spermatogonial stem cells into mature spermatozoa. This process depends not only on the differentiation capacity of germ cells but also on the supportive functions of somatic cells such as Sertoli and Leydig cells, and on molecular signaling pathways. Disruptions in this process may result in azoospermia, the absence of sperm in the ejaculate, which is classified into obstructive and non-obstructive azoospermia (NOA). Disorders resulting from intrinsic defects in germ cells are considered under NOA, including maturation arrest, hypospermatogenesis, and Sertoli cell-only syndrome. In this study, testicular biopsies were analyzed from patients with different NOA subtypes, collected following unsuccessful micro-TESE (mTESE) procedures. Genes previously associated with spermatogenesis, such as Ying Yang 1 (YY1) and Raf Kinase Inhibitor Protein (RKIP), along with MAPK1, MAP2K1, EZH2, and CP2c—identified through STRING analysis—were evaluated for their expression levels using both molecular (qPCR) and immunohistochemical (IHC) methods. A total of 27 patients diagnosed with hypospermatogenesis, early maturation arrest, or Sertoli cell-only syndrome between 2018 and 2023 at Ege University Faculty of Medicine were included. qPCR was performed for each gene in each patient, and corresponding paraffin-embedded samples were evaluated immunohistochemically using specific antibodies. Protein expression was scored using the H-score method. Protein expression (H-score) were compared in groups statistically using one-way ANOVA. Results were obtained with ages of patients and other clinical parameters such as FSH, LH and testesterone volume. Immunohistochemically, MAPK1 and MAP2K1 showed strong cytoplasmic expression in the hypospermatogenesis group, whereas Sertoli cell-only samples showed limited staining due to the absence of germ cells. RKIP, CP2c, and EZH2 showed low positivity in hypospermatogenesis, and mostly focal or negative staining in early maturation arrest and Sertoli cell-only groups. YY1 showed no detectable protein expression in any group. However, qPCR revealed that only YY1 showed significant differences among groups, suggesting transcriptional activity without protein translation, explaining the negative IHC results. These findings indicate that decreased expression correlates with germ cell loss, and highlight the potential roles of these genes in spermatogenesis. The suppression of key transcription factors in impaired spermatogenic processes may represent a critical regulatory mechanism worth further investigation.

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