Deficient Expression of DGCR8 in Human Testis is Related to Spermatogenesis Dysfunction, Especially in Meiosis I.

INTRODUCTION: DiGeorge syndrome critical region gene 8 (DGCR8) contributes to miRNA biogenesis, and defects in its expression could lead to defects in spermatogenesis. METHODS: Here, we assess gene and protein expression levels of DGCR8 in the testicular biopsy specimens obtained from men with obstructive azoospermia (OA, n = 19) and various types of non-obstructive azoospermia (NOA) including maturation arrest (MA, n = 17), Sertoli cell-only syndrome (SCOS, n = 20) and hypospermatogenesis (HYPO, 18). Also, samples of men with NOA were divided into two groups based on successful and unsuccessful sperm recovery, NOA+ in 21 patients and NOA- in 34 patients. RESULTS: Examinations disclosed a severe decrease in DGCR8 in samples with MA and SCOS in comparison to OA samples (P < 0.001). Also, the results showed DGCR8 has significantly lower expression in testis tissues of NOA- group in comparison to NOA+ group (p<0.05). Western blot analysis confirmed that the DGCR8 protein was not expressed in SCOS samples and had a very low expression in MA and HYPO samples. DISCUSSION: The results of this survey showed that DGCR8 is an important gene for the entire spermatogenesis pathway. Moreover, DGCR8 gene plays an important role in the diagnosis of NOA subgroups, and also the expression changes in it might contribute to SCOS or MA phenotypes. This gene with considering other related genes can also be a predictor of sperm retrieval.

Testicular expression of TDRD1, TDRD5, TDRD9 and TDRD12 in azoospermia.

BACKGROUND: Tudor domain-containing proteins (TDRDs) play a critical role in piRNA biogenesis and germ cell development. piRNAs, small regulatory RNAs, act by silencing of transposons during germline development and it has recently been shown in animal model studies that defects in TDRD genes can lead to sterility in males. METHODS: Here we evaluate gene and protein expression levels of four key TDRDs (TDRD1, TDRD5, TDRD9 and TDRD12) in testicular biopsy samples obtained from men with obstructive azoospermia (OA, n = 29), as controls, and various types of non-obstructive azoospermia containing hypospermatogenesis (HP, 28), maturation arrest (MA, n = 30), and Sertoli cell-only syndrome (SCOS, n = 32) as cases. One-way ANOVA test followed by Dunnett's multiple comparison post-test was used to determine inter-group differences in TDRD gene expression among cases and controls. RESULTS: The results showed very low expression of TDRD genes in SCOS specimens. Also, the expression of TDRD1 and TDRD9 genes were lower in MA samples compared to OA samples. The expression of TDRD5 significantly reduced in SCOS, MA and HP specimens than the OA specimens. Indeed, TDRD12 exhibited a very low expression in HP specimens in comparison to OA specimens. All these results were confirmed by Western blot technique. CONCLUSION: TDRDs could be very important in male infertility, which should be express in certain stages of spermatogenesis.