Comparative proteomics analysis of human FFPE testicular tissues reveals new candidate biomarkers for distinction among azoospermia types and subtypes.

Understanding molecular mechanisms that underpin azoospermia and discovery of biomarkers that could enable reliable, non-invasive diagnosis are highly needed. Using label-free data-independent LC-MS/MS acquisition coupled with ion mobility, we compared the FFPE testicular proteome of patients with obstructive (OA) and non-obstructive azoospermia (NOA) subtypes hypospermatogenesis (Hyp) and Sertoli cell-only syndrome (SCO). Out of 2044 proteins identified based on ≥2 peptides, 61 proteins had the power to quantitatively discriminate OA from NOA and 30 to quantitatively discriminate SCO from Hyp and OA. Among these, H1-6, RANBP1 and TKTL2 showed superior potential for quantitative discrimination among OA, Hyp and SCO. Integrin signaling pathway, adherens junction, planar cell polarity/convergent extension pathway and Dectin-1 mediated noncanonical NF-kB signaling were significantly associated with the proteins that could discriminate OA from NOA. Comparison with 2 transcriptome datasets revealed 278 and 55 co-differentially expressed proteins/genes with statistically significant positive correlation. Gene expression analysis by qPCR of 6 genes (H1-6, RANBP1, TKTL2, TKTL1, H2BC1, and ACTL7B) with the highest discriminatory power on protein level and the same regulation trend with transcriptomic datasets, confirmed the proteomics results. In summary, our results suggest some underlying pathways in azoospermia and broaden the range of potential novel candidates for diagnosis. SIGNIFICANCE: Using a comparative proteomics approach on testicular tissue we have identified several pathways associated with azoospermia and a number of testis-specific and germ cell-specific proteins that have the potential to pinpoint the type of spermatogenesis failure. Furthermore, comparison with transcriptomics datasets based on genome-wide gene expression analyses of human testis specimens from azoospermia patients identified proteins that could discriminate between obstructive and non-obstructive azoospermia subtypes on both protein and mRNA levels. Up to our knowledge, this is the first integrated comparative analysis of proteomics and transcriptomics data from testicular tissues. We believe that the data from our study contributes significantly to increase the knowledge of molecular mechanisms of azoospermia and pave the way for new investigations in regards to non-invasive diagnosis.

Y-chromosome haplogroup architecture confers susceptibility to azoospermia factor c microrearrangements: a retrospective study.

AIM: To assess the association between azoospermia factor c microrearrangements and semen quality, and between Y-chromosome background with distinct azoospermia factor c microrearrangements and semen quality impairment. METHODS: This retrospective study, carried out in the Research Center for Genetic Engineering and Biotechnology "Georgi D. Efremov," involved 486 men from different ethnic backgrounds referred for couple infertility from 2002-2017: 338 were azoospermic/oligozoospermic and 148 were normozoospermic. The azoospermia factor c microrearrangements were analyzed with sequence tagged site and sequence family variant markers, quantitative fluorescent polymerase chain reaction, and multiplex ligation probe amplification analysis. The Y-haplogroups of all participants were determined with direct single nucleotide polymorphism typing and indirect prediction with short tandem repeat markers. RESULTS: Our participants had two types of microdeletions: gr/gr and b2/b3; three microduplications: b2/b4, gr/gr, and b2/b3; and one complex rearrangement gr/gr deletion + b2/b4 duplication. Impaired semen quality was not associated with microrearrangements, but b2/b4 and gr/gr duplications were significantly associated with haplogroup R1a (P<0.001 and P=0.003, respectively) and b2/b3 deletions with haplogroup E (P=0.005). There were significantly more b2/b4 duplication carriers in Albanians than in Macedonians with haplogroup R1a (P=0.031). CONCLUSION: Even though azoospermia factor c partial deletions/duplications and Y-haplogroups were not associated with impaired semen quality, specific deletions/duplications were significantly associated with distinct haplogroups, implying that the Y chromosome background may confer susceptibility to azoospermia factor c microrearrangements.

SNaPshot assay for the detection of the most common CFTR mutations in infertile men.

Congenital bilateral absence of vas deferens (CBAVD) is the most common CFTR-related disorder (CFTR-RD) that explains about 1-2% of the male infertility cases. Controversial data have been published regarding the involvement of CFTR mutations in infertile men with non-obstructive azoospermia and oligozoospermia. Here, we describe single base extension (SNaPshot) assay for detection of 11 common CFTR mutations: F508del, G542X, N1303K, 621+1G->T, G551D, R553X, R1162X, W1282X, R117H, 2184insA and 1717-1G->A and IVS8polyT variants. The assay was validated on 50 previously genotyped samples and was used to screen a total of 369 infertile men with different impairment of spermatogenesis and 136 fertile controls. Our results show that double heterozygosity of cystic fibrosis (CF) and CFTR-related disorder (CFTR-RD) mutations are found in a high percentage (22.7%) of infertile men with obstructive azoospermia, but not in other studied groups of infertile men. The SNaPshot assay described here is an inexpensive, fast and robust method for primary screening of the most common CFTR mutations both in patients with classical CF and CFTR-RD. It can contribute to better understanding of the role of CFTR mutations in impaired spermatogenesis, ultimately leading to improved management of infertile men.

Association study of single-nucleotide polymorphisms in FASLG, JMJDIA, LOC203413, TEX15, BRDT, OR2W3, INSR, and TAS2R38 genes with male infertility.

Infertility is a major health problem today, affecting about 15% of couples trying to conceive a child. Impaired fertility of the male factor is causative in 20% of infertile couples and contributory in up to another 30%-40%. Based on association studies, an increasing number of gene polymorphisms have been proposed to modulate the efficiency of spermatogenesis. Here, we have investigated the possible association of 9 single-nucleotide polymorphisms (SNP) in 8 different genes-FASLG, JMJDIA, LOC203413, TEX15, BRDT, OR2W3, INSR, and TAS2R38--with male infertility. We analyzed a total of 136 men with idiopathic infertility (60 azoospermic and 76 oligozoospermic) and 161 fertile controls. Our study group included individuals of different ethnic origin: 93 of the infertile men were Macedonians, 32 were Albanians, and 11 were of other origin. The control group was composed of 125 Macedonian and 36 Albanian men. The methodology included multiplex polymerase chain reaction/SNaPshot analyses, followed by capillary electrophoresis on an ABI3130 Genetic Analyzer. Of the 9 SNPs evaluated, 3 are significantly associated (P < .05) with male infertility: SNPs rs5911500 in LOC203413, rs3088232 in BRDT, and rs11204546 in OR2W3. SNP rs5911500 showed the strongest association with infertility among Albanians (P = .0001), whereas rs3088232 was most significantly associated with azoospermia among Macedonians (P = .0082). Moreover, the frequency of co-occurrence of LOC203413 minor T allele with either homozygosity or heterozygosity for the BRDT minor G allele was significantly higher among both azoospermic (6 of 60 [10%]; P = .0057; odds ratio [95% confidence interval], 8.83 [1.73-45.08]) and oligozoospermic (10 of 76 [13.2%]; P = .0002; odds ratio [95% confidence interval], 12.04 [2.57-56.47]) men in comparison with fertile controls (2 of 161 [1.2%]).

Quantitative fluorescent-PCR detection of sex chromosome aneuploidies and AZF deletions/duplications.

The most common genetic causes of spermatogenic failure are sex chromosomal abnormalities (most frequently Klinefelter's syndrome) and deletions of the azoospermia factor (AZF) regions (AZFa, AZFb, and AZFc) of the Y chromosome. Several studies have proposed that partial AZFc deletions/duplications may be a risk factor for spermatogenic impairment. We describe a multiplex quantitative fluorescent-polymerase chain reaction (QF-PCR) method that allows simultaneous detection of these genetic causes and risk factors of male infertility. The 11-plex QF-PCR permitted the amplification of the amelogenin gene, four polymorphic X-specific short tandem repeat (STR) markers (XHPRT, DXS6803, DXS981, and exon 1 of the androgen receptor gene), nonpolymorphic Y-specific marker (SRY gene), polymorphic Y-specific STR marker (DYS448), and coamplification of DAZ/DAZL, MYPT2Y/MYPT2, and two CDY2/CDY1 fragments that allow for determination of the DAZ, MYPT2Y, and CDY gene copy number. A total of 357 DNA samples from infertile/subfertile men (n = 205) and fertile controls (n = 152) was studied. We detected 14 infertile males with sex chromosome aneuploidy (10 with Klinefelter's syndrome, 2 XX, and 2 XYY males). All previously detected AZF deletions, that is, AZFc (n8), AZFb (n1), AZFb + c (n1), gr/gr (n11), gr/gr with b2/b4 duplication (n3), and b2/b3 (n5), gave a specific pattern with the 11-plex QF-PCR. In addition, 32 DNA samples showed a pattern consistent with presence of gr/gr or b2/b4 and 4 with b2/b3 duplication. We conclude that multiplex QF-PCR is a rapid, simple, reliable, and inexpensive method that can be used as a first-step genetic analysis in infertile/subfertile patients.

AZF deletions in infertile men from the Republic of Macedonia.

Y chromosome deletions in the three azoospermia factor (AZF) regions constitute the most common genetic cause of spermatogenic failure. The aim of this study was to estimate the length and boundaries of the AZF deletions and to correlate the AZF deletions with the sperm concentrations, testicular histology, Y haplogroups and the ethnic origin of the men with deletions. PCR analysis of STS loci in the three AZF regions was used to characterize the deletions. Y haplogroup was predicted from a set of 17 Y short tandem repeats (STR) marker values. A total of nine men out of 218 infertile/subfertile men showed the presence of Y microdeletions. In eight patients the results were consistent with the presence of AZFc deletions, while in one patient a larger deletion involving both AZFb and AZFc regions was detected. In two patients, the deletion, initially diagnosed as AZFc, involved part of the distal part of the AZFb region and in one of them the deletion also extended into the region distal to the AZFc. The 3.5 Mb AZFc deletion, due to homologous recombination between b2 and b4 amplicons, was detected in six men (66.7% of all Y deletions), thus being the most common type of AZF deletion among infertile men from the Republic of Macedonia. Patients with the 3.5 Mb AZFc deletion had azoospermia or severe oligozoospermia and variable histological results [Sertoly cell only syndrome (SCOS), maturity arrest (MA) and hypospermatogenesis (HSG)]. They were of different ethnic origin (Macedonian, Albanian and Romany) and belonged to different Y haplogroups (I1b, J2, E3b and G).