Proteomic Analysis of Testis Biopsies in Men Treated with Injectable Testosterone Undecanoate Alone or in Combination with Oral Levonorgestrel as Potential Male Contraceptive

Abstract

Treatment with injectable testosterone undecanoate (TU) alone or in combination with oral levonorgestrel (LNG) resulted in marked decreases in sperm concentrations. In this study, we used proteomic analyses to examine the cellular/molecular events occurring in the human testis after TU or TU + LNG treatment. We conducted a global proteomic analysis of the human testicular biopsies before and at 2 weeks after TU alone or TU + LNG treatment. Proteins showing significant changes in expression were identified and analyzed. As a result, 17 and 46 protein spots were found with significant differential expression after the treatment with TU alone and TU + LNG, respectively. TU treatment changed the expression of heterogeneous nuclear ribonucleoprotein K (hnRNP K), proteasome inhibitor PI31 subunit (PSMF1), and superoxide dismutase [Mn] mitochondrial precursor (SOD2). These proteins inhibit "assembly", induce cell death, and promote compensatory "cell survival" in the testis. After TU + LNG treatment, "proliferation/cell survival" and "apoptosis/death" were the predominant responses in the testis. TU + LNG treatment inhibited the expression of Prolyl 4-hydroxylase beta subunit (P4HB) and Annexin A2 (Annexin II). These proteins are involved in apoptosis and cell proliferation, respectively. TU + LNG treatment also enhanced the expression of SOD2 and Parvalbumin alpha (Pvalb). These two proteins may protect testicular cells against apoptosis/death and promote cell survival. In conclusion, TU and TU + LNG treatments suppress spermatogenesis through different pathways by changing the expression of different proteins. hnRNP K, PSMF1, SOD2, P4HB, Annexin II, and Pvalb, are key proteins that may be early molecular targets responsible for spermatogenesis suppression induced by hormone treatment.

Proteomics of spermatogenesis: from protein lists to understanding the regulation of male fertility and infertility

“…Second, with western blotting, antibodies specific for PTMs can identify spots in a gel containing proteins with these modifications. 60 In our studies, 21,22,32,37,39,49,57 most of the proteome profiles related to spermatogenesis were established by 2DE-MS, and many proteins were represented by two or more spots in the gel, which indicated PTMs such as phosphorylation.…”

“…A total of 17 and 46 protein spots were found to exhibit significant differential expression after treatment with TU alone or TU1LNG. 57 These key proteins may be the early molecular targets responsible for the suppression of spermatogenesis induced by hormone treatment and may provide new avenues for the management of human infertility and novel targets for contraceptive development. PERSPECTIVE 2DE-MS is a well-established technique with well-developed reagents and instrumentation.…”

Mapping of the Human Testicular Proteome and its Relationship With That of the Epididymis and Spermatozoa

“…There are publications on whole testicular proteomes of pigs (7), mice (8 -10) and rats (11). More recently a human testicular proteome (12,13) and proteomic changes associated with contraceptives usage (14) have been published. However, the cellular localization of these proteins is largely unknown.…”

An integrated bioinformatics analysis of mouse testis protein profiles with new understanding

“…The proteomics of mammal testis should be the first effort to describe these processes and deal with testis-specific proteins to explore their structures and functions as well as their implicated clinical applications. However, fewer related works were done systematically, most of which focused mainly on the description of protein isoforms, differential protein expressions (7,8,10,11). Limitations and biases of traditional proteomics stunt functional analysis (18).…”

“…Proteomic analysis of spermatogenesis (7) and porcine (8), mouse (9), human testis (10,11) provided useful resources for studying of the testis developmental biology and pathology. However, most of these data were not publicly available and were not validated furtherly on gene or protein levels, and it also included many abundance proteins.…”