Pathogenic variants of ATG4D in infertile men with non-obstructive azoospermia identified using whole-exome sequencing.

Non-obstructive azoospermia (NOA) is the most severe form of male infertility, and it is primarily associated with genetic defects. We performed whole-exome sequencing of 236 patients with NOA and identified a homozygous pathogenic variant of autophagy-related 4D cysteine peptidase (ATG4D) in two siblings from a consanguineous family and compound heterozygous pathogenic variants of ATG4D in two sporadic cases. The expression of LC3B, a regulator of autophagic activity, was significantly decreased, and the apoptosis rate of spermatogenic cells in testicular tissues was increased. Transfection of GC-2spd cells with a ATG4D mutant plasmid (Flag-Atg4dmut ) significantly decreased the expression level of Lc3b and increased the rate of apoptosis. Moreover, a pathogenic variant in X-linked ATG4A and compound heterozygous pathogenic variants of ATG4B were identified in one patient each. All novel variants were segregated by disease phenotype and were predicted to be pathogenic. Our findings revealed that autophagy-related cysteine peptidase family genes may play crucial roles in human spermatogenesis and identified ATG4D as a novel candidate gene for male infertility due to NOA.

[Clinical report of testicular hypoplasia combined with 21-hydroxylase deficiency].

OBJECTIVE To investigate the correlation of 21-hydroxylase deficiency (21-OHD) with male testicular dysplasia. METHODS Clinical data of 8 infertile males with congenital adrenal hyperplasia due to 21-OHD was retrospectively analyzed. In addition, potential mutations of the CYP21A2 gene was detected. RESULTS All patients were referred because of azoospermia or severe oligospermia and had small testis with averaged testicular volume of 6.1 mL. Three patients had testicular adrenal rest tumors. Endocrinologic examinations revealed low levels of leutinizing hormone and follicular stimulating hormone, normal or elevated testosterone, elevated progesterone, elevated or normal adrenocoticotropic hormone, and low or normal cortisol. All patients had adrenal cortical hyperplasia, 5 with adrenal adenoma, 1 case associated with bilateral adrenal myelolipoma. All patients were given glucocorticoid replacement therapy for 3 to 6 months, which successfully improved the seminal status of 6 patient and resulted pregnancies in 5 couples. Seven pathogenic mutations of the CYP21A2 gene among the 8 patients. CONCLUSION 21-OHD can cause testicular hypoplasia and spermatogenic failure. Glucocorticoids and operations can obtain good result and improve spermatogenesis. Our results have shown a good genotype/phenotype correlation in these cases. All patients have carried the p.Ile172Asn mutation, which is associated with simple virilizing form.

Blood and semen paraoxonase-arylesterase activities in normozoospermic and azoospermic men.

Paraoxonase and arylesterase enzymes are corner stones of antioxidant defence. We aimed to compare azoospermic infertile men and normozoospermic individuals with respect to total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), paraoxonase and arylesterase levels in the blood and seminal plasma. Two-hundred consecutive infertility patients and voluntarily participated were included. In the normozoospermic group, TAS, PON, arylesterase values were statistically significantly higher when compared with those in the azoospermic group, while lower TOS and OSI levels were observed in the blood and seminal plasma of azoospermic group. In the semen analyses of normozoospermic group, the correlation between semen volume, sperm concentration, sperm motility and morphology and TAS, TOS, OSI, PON and arylesterase values was examined. A negative correlation was determined between semen volume and OSI. Levels of serum oxidative parameters were higher in the azoospermic group relative to normozoospermic group, but antioxidant parameters were lower than those of the normozoospermic group. Oxidative stress performs an essential role in the aetiology of male infertility by negatively influencing sperm quality and function. Assessment of blood and seminal plasma oxidative profiles might be an important tool to better evaluation of sperm reproductive capacity and functional competence.

Next generation sequencing with copy number variant detection expands the phenotypic spectrum of HSD17B4-deficiency.

BACKGROUND: D-bifunctional protein deficiency, caused by recessive mutations in HSD17B4, is a severe, infantile-onset disorder of peroxisomal fatty acid oxidation. Few affected patients survive past two years of age. Compound heterozygous mutations in HSD17B4 have also been reported in two sisters diagnosed with Perrault syndrome (MIM # 233400), who presented in adolescence with ovarian dysgenesis, hearing loss, and ataxia. CASE PRESENTATION: An adult male presented with cerebellar ataxia, peripheral neuropathy, hearing loss, and azoospermia. The clinical presentation, in combination with biochemical findings in serum, urine, and muscle biopsy, suggested a mitochondrial disorder. Commercial genetic testing of 18 ataxia and mitochondrial disease genes was negative. Targeted exome sequencing followed by analysis of single nucleotide variants and small insertions/deletions failed to reveal a genetic basis of disease. Application of a computational algorithm to infer copy number variants (CNVs) from exome data revealed a heterozygous 12 kb deletion of exons 10-13 of HSD17B4 that was compounded with a rare missense variant (p.A196V) at a highly conserved residue. Retrospective review of patient records revealed mildly elevated ratios of pristanic:phytanic acid and arachidonic:docosahexaenoic acid, consistent with dysfunctional peroxisomal fatty acid oxidation. CONCLUSION: Our case expands the phenotypic spectrum of HSD17B4-deficiency, representing the first male case reported with infertility. Furthermore, it points to crosstalk between mitochondria and peroxisomes in HSD17B4-deficiency and Perrault syndrome.

Association of the gonadotrophin-regulated testicular RNA helicase gene polymorphism with human male infertility.

Gonadotrophin-regulated testicular RNA helicase (GRTH) plays an important role in RNA functions including nuclear transcription, pre-mRNA splicing and it regulates the translation of specific genes required for the progression of spermatogenesis. In this study, we analysed the association of GRTH gene IVS6+55G/T and c.852C/T polymorphisms with human male infertility. The study showed c.852 T allele was associated with an increased risk of male infertility (OR: 3.16, P = 0.008), whereas IVS6+55G/T allele conferred no risk. In Indian population, this is the first report on association of GRTH gene SNP polymorphism and male infertility and it underscores the significance of GRTH genotypes in modulating the risk of male infertility.

The RNase III enzyme DROSHA is essential for microRNA production and spermatogenesis.

DROSHA is a nuclear RNase III enzyme responsible for cleaving primary microRNAs (miRNAs) into precursor miRNAs and thus is essential for the biogenesis of canonical miRNAs. DICER is a cytoplasmic RNase III enzyme that not only cleaves precursor miRNAs to produce mature miRNAs but also dissects naturally formed/synthetic double-stranded RNAs to generate small interfering RNAs (siRNAs). To investigate the role of canonical miRNA and/or endogenous siRNA production in spermatogenesis, we generated Drosha or Dicer conditional knock-out (cKO) mouse lines by inactivating Drosha or Dicer exclusively in spermatogenic cells in postnatal testes using the Cre-loxp strategy. Both Drosha and Dicer cKO males were infertile due to disrupted spermatogenesis characterized by depletion of spermatocytes and spermatids leading to oligoteratozoospermia or azoospermia. The developmental course of spermatogenic disruptions was similar at morphological levels between Drosha and Dicer cKO males, but Drosha cKO testes appeared to be more severe in spermatogenic disruptions than Dicer cKO testes. Microarray analyses revealed transcriptomic differences between Drosha- and Dicer-null pachytene spermatocytes or round spermatids. Although levels of sex-linked mRNAs were mildly elevated, meiotic sex chromosome inactivation appeared to have occurred normally. Our data demonstrate that unlike DICER, which is required for the biogenesis of several small RNA species, DROSHA is essential mainly for the canonical miRNA production, and DROSHA-mediated miRNA production is essential for normal spermatogenesis and male fertility.

Genetic variants of eNOS gene may modify the susceptibility to idiopathic male infertility.

In testis, eNOS is responsible for synthesis of nitric oxide (NO) which is an essential gas message regulator in spermatogenesis, suggesting that eNOS gene plays a role in normal spermatogenesis and the genetic variants of eNOS gene may be potential genetic risk factors of spermatogenesis impairment. In this study, the polymorphic distributions of three common polymorphism loci including T-786C, 4A4B and G894T in eNOS gene were investigated in 355 Chinese infertile patients with azoospermia or oligozoospermia and 246 healthy fertile men and a meta-analysis was carried in order to explore the possible relationship between the three loci of eNOS gene and male infertility with spermatogenesis impairment. As a result, allele -786C of T-786C (11.4% versus 6.5%, p = 0.004) and 4A of 4A4B (11.0% versus 6.3%, p = 0.005) as well as genotype TC of T-786C (22.8% versus 13.0%, p = 0.002) and AB of 4A4B (18% versus 11%, p = 0.015) were significantly associated with idiopathic male infertility. The haplotypes T-4A-G (7.4% versus 4.1%, p = 0.015) and C-4B-G (7.6% versus 4.4%, p = 0.028) could increase the susceptibility to male infertility, whereas haplotype T-4B-G (67.0% versus 75.2%, p = 0.002) might be a protective factor for male infertility. The results of meta-analysis revealed that the polymorphism of T-786C was associated with male infertility. These findings suggested that the variants of eNOS gene may modify the susceptibility to male infertility with impaired spermatogenesis.

Prolidase enzyme activity in varicose venous walls related to sperm count in patients with varicocele.

OBJECTIVES: To investigate peripheral, seminal and varicose venous wall prolidase enzyme activities and their relationships between sperm parameters in patients with varicocele. DESIGN AND METHODS: Prolidase enzyme activities were determined in blood, seminal fluid and varicose vein walls in patients with grade 3 varicocele. Sperm parameters were also measured and the relationships between prolidase enzyme and sperm parameters were assessed by statistical correlation analysis. RESULTS: There was a significant and negative correlation between sperm counts and varicose venous wall prolidase enzyme activities (r = -0.618, p < 0.001) and a positive significant correlation between sperm counts and seminal fluid prolidase enzyme activities (r = 0.676, p < 0.001). None of the parameters were correlated with sperm motility indices. CONCLUSION: Varicose venous wall prolidase enzyme activity could be an important factor in progression of azoospermia and infertility in patients with varicocele.

Caspase signalling pathways in human spermatogenesis.

PURPOSE: Little is known about the apoptotic mechanisms involved in abnormal spermatogenesis. In order to describe the significance of apoptosis in azoospermia, testicular tissue from abnormal spermatogenesis was analysed. METHODS: Testicular treatment biopsies were obtained from 27 men. Five presented oligozoospermia, 9 obstructive azoospermia (4 congenital bilateral absence of the vas deferens; 5 secondary azoospermia) and 13 non-obstructive azoospermia (5 hypospermatogenis; 3 maturation arrest; 5 Sertoli-cell-only syndrome). Immunohistochemical staining was performed for active caspases-3, -8 and -9. The presence of active caspases in Sertoli cells and germ cells was analyzed using stereological tools. RESULTS: Increased active caspase-3 was found in Sertoli-cell-only syndrome. No significant differences were found in maturation arrest. In hypospermatogenesis, primary spermatocytes were the germ cells with higher active caspases. Oligozoospermia and secondary obstruction showed significant differences among germ cells for the presence of all active caspases. In oligozoospermia, spermatogonia presented significant increased active caspase-9 in relation to active caspase-8. In primary obstruction and hypospermatogenesis, germ cells presented significant increased active caspases-3 and -9. CONCLUSIONS: Results suggest that increased active caspase-3 might be involved in Sertoli-cell-only syndrome etiology. In cases of hypospermatogenesis, intrinsic lesions at the meiotic stage seem to be related to the pathology. In secondary obstruction apoptosis is suggested to be initiated due to extrinsic and intrinsic lesions, whereas in primary obstruction only the intrinsic apoptotic pathway seems to be present. Finally, in oligozoospermic patients spermatogonia death by mitochondrial damage additionally to meiosis malfunctioning, might be on the origin of the decreased sperm output.

[Neutral alpha-glucosidase activity is correlated with the location of epididymal obstruction in azoospermia men].

OBJECTIVE: To evaluate the correlation of neutral alpha-glucosidase in seminal plasma with the location of epididymal obstruction in azoospermia men. METHODS: We detected neutral alpha-glucosidase activity in the seminal plasma of 59 men with obstructive azoospermia followed by determining the location of epididymal obstruction by scrotal exploratory surgery. Then we analyzed the correlation between neutral alpha-glucosidase and the location of epididymal obstructive azoospermia. RESULTS: Among the total number of patients, there were 25 cases of bilateral cauda epididymal obstruction, 15 bilateral corpus, 12 bilateral caput, 4 unilateral caput-opposite cauda, and 3 unilateral corpus-opposite cauda. The neutral alpha-glucosidase levels in the seminal plasma of bilateral cauda, corpus and capus epididymal obstructions were (4.1 +/- 1.9), (13.8 +/- 4.4) and (46.8 +/- 19.3) mU per ejaculate, respectively, with statistically significant differences among the three groups (P < 0.05). CONCLUSION: Neutral alpha-glucosidase activity is significantly correlated with the location of epididymal obstruction in azoospermia men, which helps to locate epididymal obstruction, evaluate surgical prognosis and reduce the time of scrotal exploratory surgery.

Êxpression of inducible nitric oxide synthase (iNOS) in the azoospermic human testis.

Azoospermia, which is the absence of spermatozoa in the ejaculate, is not a rare cause of male infertility. Inducible nitric oxide synthase (iNOS) is a calcium-independent NOS, which is present in the testis and involved in spermatogenesis, and apoptosis of Sertoli and germ cells. Twenty idiopathic infertile men presenting nonobstructive azoospermia were enrolled in this study, and testicular sperm extraction procedures were performed. Tissue extracts were dissected, and the fluid samples were investigated to determine the presence of spermatozoa. Histologic evaluation of the spermatozoa-present samples revealed that seminiferous tubules were normal and were lined by Sertoli cells and spermatogenic cells. However, in the spermatozoa-absent samples, the diameter of the seminiferous tubules was small, and Sertoli-cell-only syndrome was determined in most of the tubules. iNOS expression was very weak in Sertoli cells, germ cells, and in Leydig cells in the spermatozoa-present group. In the spermatozoa-absent group, the immunostaining was very intense in Sertoli and Leydig cells. Electron microscopy findings were supported the histologic results. In conclusion, complete germ cell loss and intense expression of iNOS in the Sertoli and Leydig cells in the spermatozoa-absent groups of azoospermic human testis suggest an essential role of iNOS in spermatogenesis.

Genome-wide expression of azoospermia testes demonstrates a specific profile and implicates ART3 in genetic susceptibility.

Infertility affects about one in six couples attempting pregnancy, with the man responsible in approximately half of the cases. Because the pathophysiology underlying azoospermia is not elucidated, most male infertility is diagnosed as idiopathic. Genome-wide gene expression analyses with microarray on testis specimens from 47 non-obstructive azoospermia (NOA) and 11 obstructive azoospermia (OA) patients were performed, and 2,611 transcripts that preferentially included genes relevant to gametogenesis and reproduction according to Gene Ontology classification were found to be differentially expressed. Using a set of 945 of the 2,611 transcripts without missing data, NOA was further categorized into three classes using the non-negative matrix factorization method. Two of the three subclasses were different from the OA group in Johnsen's score, FSH level, and/or LH level, while there were no significant differences between the other subclass and the OA group. In addition, the 52 genes showing high statistical difference between NOA subclasses (p < 0.01 with Tukey's post hoc test) were subjected to allelic association analyses to identify genetic susceptibilities. After two rounds of screening, SNPs of the ADP-ribosyltransferase 3 gene (ART3) were associated with NOA with highest significance with ART3-SNP25 (rs6836703; p = 0.0025) in 442 NOA patients and 475 fertile men. Haplotypes with five SNPs were constructed, and the most common haplotype was found to be under-represented in patients (NOA 26.6% versus control 35.3%, p = 0.000073). Individuals having the most common haplotype showed an elevated level of testosterone, suggesting a protective effect of the haplotype on spermatogenesis. Thus, genome-wide gene expression analyses were used to identify genes involved in the pathogenesis of NOA, and ART3 was subsequently identified as a susceptibility gene for NOA. These findings clarify the molecular pathophysiology of NOA and suggest a novel therapeutic target in the treatment of NOA.

Study of GT-repeat expansion in Heme oxygenase-1 gene promoter as genetic cause of male infertility.

PURPOSE: The length of GT-repeats polymorphic region in the promoter of human Heme oxygenase-1 gene (HO-1) alters the level of its transcriptional activity in response to oxidative stresses. Decreased level of HO-1 protein in the seminal plasma has been reported to be associated with oligospermia and azoospermia in male infertility. This is the first study to investigate the association between GT-repeats expansion in the promoter of the HO-1 gene and male infertility. METHODS: The frequencies of different GT-repeats alleles in the promoter of HO-1 gene were determined in 100 cases and 100 normal controls using PCR-PAGE, ABI fragment analysis genotyping and sequencing analysis. RESULTS: All alleles were classified into S and L alleles. S alleles were specified as number 0 to 3 with <27 GT-repeats and L alleles were specified as number 4 to 6 with >27 repeats. The L allele frequency was significantly higher among case group (54.5%) than that was obtained in the normal control group (37.5%). Statistical analysis provided a significant relationship between L allele and male infertility (P < 0.001). CONCLUSIONS: This study shows for the first time that GT-repeats expansion in promoter of the HO-1 gene is associated with oligospermia and azoospermia among Iranian infertile cases.

[Expression of heme oxygenase enzyme in the testis tissue and azoospermia].

OBJECTIVE: To investigate the location of heme oxygenase (HO) enzyme in the human testis, and explore the correlation of the expression of HO enzyme with azoospermia by analyzing its different expression levels in the testes of nonobstructive azoospermia, obstructive azoospermia and normal men. METHODS: We detected the location of the cells expressing HO enzyme in the human testis tissue using immunohistochemistry, determined the mRNA and protein expression levels of HO-1 and HO-2 in the testes of azoospermia patients and normal healthy men by RT-fluorescence quantitative PCR (RT-FQ-PCR) and Western blot, and explored the correlation of HO expressions with the pathogenesis of azoospermia. RESULTS: HO-1 enzyme was expressed mainly in the Sertoli cells and HO-2 enzyme chiefly in the germ cells of the testis tissue. RT-FQ-PCR showed that the expression of HO-1 in the testis tissue was significantly lower in the nonobstructive azoospermia than in the normal and obstructive azoospermia groups (P < 0.05), with no significant difference between the latter two. Western blot revealed no obvious difference between the expression level of HO-1 protein and that of HO-1 mRNA. There were no differences in the expression level of HO-2 protein among the three groups. CONCLUSION: The expression level of HO enzyme is significantly decreased in the testis tissue of nonobstructive azoospermia patients, and the expression of HO-1 protein is consistent with that of HO-1 mRNA. As HO-1 protects the testis tissue against various stress injuries through its antioxidant, anti-inflammatory and anti-apoptotic effects, its decreased expression level may be correlated with spermatogenic dysfunction, and therefore considered as a possible mechanism of nonobstructive azoospermia.

Testicular steroid sulfatase overexpression is associated with Leydig cell dysfunction in primary spermatogenic failure.

BACKGROUND: Decreased testosterone (T) to LH ratio and increased 17ß-estradiol (E2) serum concentrations represent a common finding among patients with severe spermatogenic failure, suggesting a concurrent Leydig cell steroidogenic dysfunction. Aromatase overexpression has been associated with increased serum and intratesticular E2 in these patients. However, it is unknown whether the sulfatase pathway contributes to the increased availability of active estrogens in patients with primary spermatogenic failure. OBJECTIVES: To assess estrogen sulfotransferase (SULT1E1) and steroid sulfatase (STS) mRNA abundance in testicular tissue of patients with Sertoli cell-only syndrome (SCOS) and normal tissues, its association with serum and intratesticular hormone levels, and to explore the mRNA and protein testicular localization of both enzymes. MATERIALS AND METHODS: Testicular tissues of 23 subjects with SCOS (cases) and 22 patients with obstructive azoospermia and normal spermatogenesis (controls) were obtained after biopsy. SULT1E1 and STS transcripts accumulation was quantified by RT-qPCR. For mRNA and protein localization, we performed RT-qPCR in Leydig cell clusters and seminiferous tubules isolated by laser-capture microdissection and immunofluorescence in testicular tissues. Serum and intratesticular hormones were measured by immunoradiometric assays. RESULTS: SULT1E1 mRNA accumulation was similar in both groups. The amount of STS mRNA was higher in cases (p = 0.007) and inversely correlated with T/LH ratio (r = -0.402; p = 0.02). Also, a near significant correlation was observed with intratesticular E2 (r = 0.329, p = 0.057), in agreement with higher intratesticular E2 in cases (p < 0.001). Strong STS immunoreaction was localized in the wall of small blood vessels but not in Leydig cells. Both SULT1E1 and STS mRNA abundance was similar in Leydig cell clusters and the tubular compartment, except for lower SUTL1E1 mRNA in the seminiferous tubules of SCOS patients (p = 0.001). CONCLUSIONS: Our results suggest that an unbalance of the STS/SULT1E1 pathway contributes to the testicular hyperestrogenic microenvironment in patients with primary spermatogenic failure and Leydig cell dysfunction.

P450-aromatase activity and expression in human testicular tissues with severe spermatogenic failure.

There is evidence that impaired spermatogenesis is associated with an imbalance in the oestradiol/testosterone ratio and with Leydig cell (LC) dysfunction. In testis, P450-aromatase, encoded by CYP19, is responsible for the conversion of testosterone to oestradiol. The aims of this study were to quantify CYP19 mRNA expression, aromatase activity and protein localization, and to measure the oestradiol to testosterone ratio in testicular tissues of men with spermatogenic impairment. Twenty-four men with complete Sertoli cell-only syndrome (SCOS), 14 with focal SCOS, 14 with maturation arrest (MA), 8 with mixed atrophy and 30 controls with normal spermatogenesis were subjected to testicular biopsy. All subjects underwent a physical examination, cytogenetic and serum hormonal studies. Testicular CYP19 mRNA was quantified using real time RT-PCR. Testicular aromatase activity was measured using the (3)H(2)0 assay and protein expression was evaluated using immunohistochemistry. In cases, serum testosterone and oestradiol were normal, but the testosterone/LH ratio was lower compared with controls (p < 0.05). Aromatase was localized in the Leydig, Sertoli and germ cells of all tissues, although stronger intensity was observed in LC. Aromatase mRNA and activity were not altered in cases and correlated positively with LC number (r = 0.516 and r = 0.369; p < 0.008). The intratesticular oestradiol/testosterone ratio was elevated (p = 0.005) in complete SCOS patients compared with controls. In conclusion, testicular aromatase seems to be normal in most subjects with impaired spermatogenesis. However, an altered intratesticular oestradiol/testosterone ratio in some patients with complete SCOS suggests that aromatase is increased, which might contribute to Leydig cell dysfunction.

Deletion of Ck2ß gene causes germ cell development arrest and azoospermia in male mice.

OBJECTIVES: In humans, non-obstructive azoospermia (NOA) is a major cause of male infertility. However, the aetiology of NOA is largely unknown. Previous studies reported that protein CK2ß was abundantly and broadly expressed in spermatogenic cells. Here, we investigate whether protein CK2ß participates in spermatogenesis. MATERIALS AND METHODS: In this study, we separated spermatogenic cells using STA-PUT velocity sedimentation, analysed the expression pattern of protein CK2ß by immunoblotting, specifically deleted Ck2ß gene in early-stage spermatogenic cells by crossing Ck2ßfl mice with Stra8-Cre+ mice and validated the knockout efficiency by quantitative RT-PCR and immunoblotting. The phenotypes of Ck2ßfl/Δ ;SCre+ mice were studied by immunohistochemistry and immunofluorescence. The molecular mechanisms of male germ cell development arrest were elucidated by immunoblotting and TUNEL assay. RESULTS: Ablation of Ck2ß gene triggered excessive germ cell apoptosis, germ cell development arrest, azoospermia and male infertility. Inactivation of Ck2ß gene caused distinctly reduced expression of Ck2α' gene and CK2α' protein. CONCLUSIONS: Ck2ß is a vital gene for germ cell survival and male fertility in mice.

Dual histone methyl reader ZCWPW1 facilitates repair of meiotic double strand breaks in male mice.

Meiotic crossovers result from homology-directed repair of DNA double-strand breaks (DSBs). Unlike yeast and plants, where DSBs are generated near gene promoters, in many vertebrates DSBs are enriched at hotspots determined by the DNA binding activity of the rapidly evolving zinc finger array of PRDM9 (PR domain zinc finger protein 9). PRDM9 subsequently catalyzes tri-methylation of lysine 4 and lysine 36 of Histone H3 in nearby nucleosomes. Here, we identify the dual histone methylation reader ZCWPW1, which is tightly co-expressed during spermatogenesis with Prdm9, as an essential meiotic recombination factor required for efficient repair of PRDM9-dependent DSBs and for pairing of homologous chromosomes in male mice. In sum, our results indicate that the evolution of a dual histone methylation writer/reader (PRDM9/ZCWPW1) system in vertebrates remodeled genetic recombination hotspot selection from an ancestral static pattern near genes towards a flexible pattern controlled by the rapidly evolving DNA binding activity of PRDM9.

Azoospermic infertility is associated with altered expression of DNA repair genes.

Compelling evidence suggest that germs cells are predominantly sensitive to DNA damaging agents in comparison to other cells. High fidelity DNA repair in testicular cells thus becomes indispensable to preserve the genomic integrity for passing on to the progeny. Compromised DNA repair machinery in the testicular cells may result in impaired spermatogenesis and infertility. It remains unclear if the alterations in the expression of DNA repair genes correlate with azoospermia and male infertility. In the present study, 54 non-obstructive azoospermic infertile patients with hypospermatogenesis (HS, n = 26), maturation arrest (MA, n = 15), Sertoli cell only syndrome (SCOS, n = 13) and 14 controls with obstructive azoospermia, but normal spermatogenesis were recruited. Expression profiling of 84 DNA repair genes in testicular biopsy samples was performed using PCR array. Out of 84 genes, 27, 64 and 28 genes showed >5 fold down-regulation in the HS, MA and SCOS groups, respectively. On the basis of differential expression and their functional significance in spermatogenesis, ten genes (MSH2, BRIP1, CCNH, LIG4, MGMT, NTHL1, PMS1, DMC1, POLB and XPA) were selected for validation of transcript levels in a higher number of cases using RT-PCR, which corroborated the findings of array. Four genes (MSH2, LIG4, PMS1 and DMC1) were analyzed for protein levels using immunohistochemistry, which further validated the loss of DNA repair gene expression. Caspase-3 immunostaining showed that the loss of DNA repair correlated with increased testicular apoptosis in patients. Maturation arrest showed the highest apoptotic index with maximum number of downregulated genes. We conclude that the loss of DNA repair genes expression in testis correlates with increased apoptosis, azoospermia and infertility.

ADAMTS1 and ADAMTS5 metalloproteases produced by Sertoli cells: a potential diagnostic marker in azoospermia.

In this study, our aim was to detect protein levels of A Disintegrin and Metalloproteinase with Thrombospondin Motifs 1 and 5 (ADAMTS1 and ADAMTS5) proteases and to examine the effect of in vitro FSH supplementation on protease production in cultured Sertoli cells. The expression of metalloproteases, ADAMTS1, and ADAMTS5 were investigated in Sertoli cell cultures as well as in ejaculate of azoospermic men which then were compared with ejaculates of the fertile control group. A total of 15 azoospermic men, diagnosed as obstructive (OA, n = 5) and nonobstructive (NOA, n = 10) azoospermia were included in the study. ADAMTS1, ADAMTS5 and FSH receptors (FSHR) were found to be expressed 2.56, 2.10, and 2.66-fold less in Sertoli cells of NOA patients, than those of OA (p < 0.05). After rFSH was added onto Sertoli cell cultures of NOA patients, their expression did not increase significantly and did not reach to levels of control group. Evaluation of ejaculates revealed that the expression of ADAMTS1 and ADAMTS5 were insignificantly 1.03 and 1.1-fold higher in OA group (p > 0.05), respectively; however, in the NOA group, their expression were 1.70 and 1.96-fold lower, respectively, when compared with the fertile control group (p < 0.05) which was statistically significant. As a conclusion, the present study has revealed that insufficiency of ADAMTS1 and ADAMTS5 expression in Sertoli cells may have an important role in the etiology of male infertility. As expected due to low FSHR expression, rFSH response is impaired in NOA patients with relatively low ADAMTS expression response; therefore, such patients might hardly benefit from rFSH treatment. Further studies with larger cohorts may reveal ADAMTSs' potential use as a predictive marker for positive sperm retrieval in azoospermic patients who are scheduled to undergo testicular sperm extraction. Abbreviations: ADAM: A Disintegrin and Metalloproteinase; ADAMTS1 and ADAMTS5: A Disintegrin and Metalloproteinase with 10 Thrombospondin Motifs 1 and 5; ADAMTS: A Disintegrin and Metalloproteinase with Thrombospondin; ABP: androgen binding protein; CAMs: cell adhesion molecules; ECM: extracellular matrix; FSH: follicle stimulating hormone; FSHR: FSH receptors; HRP: horseradish peroxidase; MMP: matrix metalloproteinases; MP: metalloproteinases; NOA: nonobstructive azoospermia; OA: obstructive azoospermia; TIMP-1: tissue inhibitor of metalloproteinase-1.