S Katoeizadeh - Department of Biology, Faculty of Science and Technology, ACECR Institute of Higher Education (Isfahan), Isfahan, Iran- Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
N Sanei Ataabadi - Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran- Department of Genetics, Faculty of Bioscience, Tarbiat Modares university, Tehran, Iran
MH Nasr-Esfahani - Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
K Dormiani - Department of Molecular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran

Background: Azoospermia is one of the causes of infertility in 10-15% of men and refers to the complete absence of sperm in ejaculate. Azoospermia divided into two major categories: Obstructive azoospermia (OA) and Non-Obstructive azoospermia (NOA). The TP1 protein plays an important role in the chromatin compression process during sperm maturation. During this process, first, TP1 replaces histones and then it is replaced by protamins. Long non-coding RNAs (lncRNAs) play significant role in regulation of gene expression in cis or trans-manner. Finding the lncRNAs related to NOA azoospermia genes may provide valuable insight into NOA azoospermia molecular mechanisms. On the other hand, lncRNAs are more specifically expressed in tissues and cells than coding genes, so they could be considered as suitable biomarkers for diagnosis of the infertility diseases.Objective: In the present study, we aimed to evaluate the expression patterns of lncRNA AC007557 (LINC01921), placed in neighboring of TNP1 gene (<10 kb). For this, the expression pattern of the TP1 was determined in NOA azoospermia using testicular biopsy of azoospermic patients. Besides, we assessed relationship between expression pattern of LINC01921 and TNP1 gene.Materials and Methods: 51 azoospermia testis tissue samples were collected from 36 Non-Obstructive azospermia (NOA) and 15 Obstructive azoospermia (OA) (as controls) from azoospermic men, referred to the Isfahan Fertility and Infertility Center for micro-TESE operation. They were classified histologically. Total RNA was extracted from tissue samples by TRIZOL regent and used for cDNA synthesis. The expression patterns of TNP1 and LINC01921 were evaluated using Real-Time PCR and analyzed with ΔΔCt method. The biomarker potential efficiency of each gene was evaluated by Receiver operating characteristic (ROC) curve.Results: The expression levels of TNP1 and its neighboring lncRNA, LINC01921, were significantly decreased in NOA samples compared to OAs. In addition, there was a significant positive correlation between TNP1 and LINC01921 expression pattern. ROC curve analysis also showed area under the curve of 0.92 and 0.83 for TNP1 and LINC01921 respectively, which confirmed their potential as azoospermia biomarkers.Conclusion: In this study, the expression levels of LINC01921 and TNP1 are evaluated in NOA samples as test and OA samples as control group. Our results demonstrated a significantly difference of expression level between two groups. Identification of neighboring lncRNA to the azoospermia gene can provide a valuable insight into male infertility and helps to detailed clarification of the molecular mechanism of the disease.

lncRNA, TNP1, Azoospermia, Male infertility