Inhibition of WNT/ß-catenin signalling during sex-specific gonadal differentiation is essential for normal human fetal testis development.

Sex-specific gonadal differentiation is directed by complex signalling promoting development in either male or female direction, while simultaneously inhibiting the opposite pathway. In mice, the WNT/ß-catenin pathway promotes ovarian development and the importance of actively inhibiting this pathway to ensure normal testis development has been recognised. However, the implications of alterations in the tightly regulated WNT/ß-catenin signalling during human fetal gonad development has not yet been examined in detail. Thus, the aim of this study was to examine the consequences of dysregulating the WNT/ß-catenin signalling pathway in the supporting cell lineage during sex-specific human fetal gonad development using an established and extensively validated ex vivo culture model. Inhibition of WNT/ß-catenin signalling in human fetal ovary cultures resulted in only minor effects, including reduced secretion of RSPO1 and reduced cell proliferation although this was not consistently found in all treatment groups. In contrast, promotion of WNT/ß-catenin signalling in testes severely affected development and function. This included disrupted seminiferous cord structures, reduced cell proliferation, reduced expression of SOX9/AMH, reduced secretion of Inhibin B and AMH as well as loss of the germ cell population. Additionally, Leydig cell function was markedly impaired with reduced secretion of testosterone, androstenedione and INSL3. Together, this study suggests that dysregulated WNT/ß-catenin signalling during human fetal gonad development severely impairs testicular development and function. Importantly, our study highlights the notion that sufficient inhibition of the opposite pathway during sex-specific gonadal differentiation is essential to ensure normal development and function also applies to human fetal gonads.

Bi-allelic variants in INSL3 and RXFP2 cause bilateral cryptorchidism and male infertility.

STUDY QUESTION: What is the impact of variants in the genes INSL3 (Insulin Like 3) and RXFP2 (Relaxin Family Peptide Receptor 2), respectively, on cryptorchidism and male infertility? SUMMARY ANSWER: Bi-allelic loss-of-function (LoF) variants in INSL3 and RXFP2 result in bilateral cryptorchidism and male infertility, whereas heterozygous variant carriers are phenotypically unaffected. WHAT IS KNOWN ALREADY: The small heterodimeric peptide INSL3 and its G protein-coupled receptor RXFP2 play a major role in the first step of the biphasic descent of the testes, and variants in the INSL3 and RXFP2 genes have long been implicated in inherited cryptorchidism. However, only one single homozygous missense variant in RXFP2 has clearly been linked to familial bilateral cryptorchidism, so the effects of bi-allelic variants in INSL3 and heterozygous variants in both genes on cryptorchidism and male infertility remain unclear. STUDY DESIGN, SIZE, DURATION: Exome data of 2412 men from the MERGE (Male Reproductive Genomics) study cohort including 1902 infertile men with crypto-/azoospermia, of whom 450 men had a history of cryptorchidism, were screened for high-impact variants in INSL3 and RXFP2. PARTICIPANTS/MATERIALS, SETTING, METHODS: For patients with rare, high-impact variants in INSL3 and RXFP2, detailed clinical data were collected and the testicular phenotype was determined. Genotyping of family members was performed to analyse the co-segregation of candidate variants with the condition. Immunohistochemical staining for INSL3 in patient testicular tissue and measuring serum INSL3 concentration was performed to analyse the functional impact of a homozygous loss-of-function variant in INSL3. For a homozygous missense variant in RXFP2, its impact on the protein's cell surface expression and ability to respond to INSL3 in CRE reporter gene assay was determined. MAIN RESULTS AND THE ROLE OF CHANCE: This study presents homozygous high-impact variants in INSL3 and RXFP2 and clearly correlates these to bilateral cryptorchidism. Functional impact of the identified INSL3 variant was demonstrated by absence of INSL3-specific staining in patients' testicular Leydig cells as well as undetectable blood serum levels. The identified missense variant in RXFP2 was demonstrated to lead to reduced RXFP2 surface expression and INSL3 mediated receptor activation. LIMITATIONS, REASONS FOR CAUTION: Further investigations are needed to explore a potential direct impact of bi-allelic INSL3 and RXFP2 variants on spermatogenesis. With our data, we cannot determine whether the infertility observed in our patients is a direct consequence of the disruption of a possible function of these genes on spermatogenesis or whether it occurs secondarily due to cryptorchidism. WIDER IMPLICATIONS OF THE FINDINGS: In contrast to previous assumptions, this study supports an autosomal recessive inheritance of INSL3- and RXFP2-related bilateral cryptorchidism while heterozygous LoF variants in either gene can at most be regarded as a risk factor for developing cryptorchidism. Our findings have diagnostic value for patients with familial/bilateral cryptorchidism and additionally shed light on the importance of INSL3 and RXFP2 in testicular descent and fertility. STUDY FUNDING/COMPETING INTEREST(S): This study was carried out within the frame of the German Research Foundation (DFG) funded by Clinical Research Unit 'Male Germ Cells: from Genes to Function' (DFG, CRU326). Research at the Florey was supported by an NHMRC grant (2001027) and the Victorian Government Operational Infrastructure Support Program. A.S.B. is funded by the DFG ('Emmy Noether Programme' project number 464240267). The authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Identification of a window of androgen sensitivity for somatic cell function in human fetal testis cultured ex vivo.

BACKGROUND: Reduced androgen action during early fetal development has been suggested as the origin of reproductive disorders comprised within the testicular dysgenesis syndrome (TDS). This hypothesis has been supported by studies in rats demonstrating that normal male development and adult reproductive function depend on sufficient androgen exposure during a sensitive fetal period, called the masculinization programming window (MPW). The main aim of this study was therefore to examine the effects of manipulating androgen production during different timepoints during early human fetal testis development to identify the existence and timing of a possible window of androgen sensitivity resembling the MPW in rats. METHODS: The effects of experimentally reduced androgen exposure during different periods of human fetal testis development and function were examined using an established and validated human ex vivo tissue culture model. The androgen production was reduced by treatment with ketoconazole and validated by treatment with flutamide which blocks the androgen receptor. Testicular hormone production ex vivo was measured by liquid chromatography-tandem mass spectrometry or ELISA assays, and selected protein markers were assessed by immunohistochemistry. RESULTS: Ketoconazole reduced androgen production in testes from gestational weeks (GW) 7-21, which were subsequently divided into four age groups: GW 7-10, 10-12, 12-16 and 16-21. Additionally, reduced secretion of testicular hormones INSL3, AMH and Inhibin B was observed, but only in the age groups GW 7-10 and 10-12, while a decrease in the total density of germ cells and OCT4+ gonocytes was found in the GW 7-10 age group. Flutamide treatment in specimens aged GW 7-12 did not alter androgen production, but the secretion of INSL3, AMH and Inhibin B was reduced, and a reduced number of pre-spermatogonia was observed. CONCLUSIONS: This study showed that reduced androgen action during early development affects the function and density of several cell types in the human fetal testis, with similar effects observed after ketoconazole and flutamide treatment. The effects were only observed within the GW 7-14 period-thereby indicating the presence of a window of androgen sensitivity in the human fetal testis.

Development and validation of a mass spectrometry-based assay for quantification of insulin-like factor 3 in human serum.

BACKGROUND: The circulating level of the peptide hormone insulin-like factor 3 (INSL3) is a promising diagnostic marker reflecting Leydig cell function in the male. Few commercial immunoassays of varying quality exist. Therefore, we decided to develop and validate a precise method for quantification of INSL3 by mass spectrometry. METHODS: We developed an assay in which the INSL3 A-chain is released from the INSL3 A-B heterodimer by chemical reduction and alkylation. The alkylated INSL3 A-chain is quantitated by liquid chromatography-tandem mass spectrometry (LC-MS/MS), as substitute for serum INSL3. The method was compared to a validated and sensitive in-house serum INSL3 immunoassay using 97 serum samples from 12 healthy boys during pubertal transition. Adult levels were determined based on sera from 72 adult healthy males aged 18-40 years. RESULTS: An LC-MS/MS assay with limit of detection and limit of quantification (LOQ) of 0.06 and 0.15 ng/mL, respectively, and intra-assay CVs <9% in the relevant ranges was obtained. The LC-MS/MS compared well with the in-house immunoassay (Deming regression slope: 1.28; Pearson correlation: R=0.86). INSL3 concentrations increased with pubertal maturation in healthy boys. INSL3 concentrations were above the LOQ in all samples from the adult men. The mean (±2 SD range)for serum INSL3 concentrations in the adult men was 2.2 (0.5-3.9) ng/mL. CONCLUSIONS: We have developed a robust and sensitive method suitable for quantitation of serum INSL3 in a clinical setting using LC-MS/MS instrumentation available in modern clinical laboratories. The method paves the way for future studies into the clinical role of serum INSL3 measurements.

Proteomics of differential extraction fractions enriched for chromatin-binding proteins from colon adenoma and carcinoma tissues.

BACKGROUND: Altered nuclear and genomic structure and function are hallmarks of cancer cells. Research into nuclear proteins in human tissues could uncover novel molecular processes in cancer. Here, we examine biochemical tissue fractions containing chromatin-binding (CB) proteins in the context of colorectal cancer (CRC) progression. METHODS: CB protein-containing fractions were biochemically extracted from human colorectal tissues, including carcinomas with chromosomal instability (CIN), carcinomas with microsatellite instability (MIN), and adenomas. The CB proteins were subjected to label-free LC-MS/MS and the data were analyzed by bioinformatics. RESULTS: Over 1700 proteins were identified in the CB fraction from colonic tissues, including 938 proteins associated with nuclear annotation. Of the latter, 169 proteins were differential between adenomas and carcinomas. In this adenoma-versus-carcinoma comparison, apart from specific changes in components of the splicing and protein translational machineries, we also identified significant changes in several proteins associated with chromatin-directed functions. Furthermore, several key cell cycle proteins as well as those involved in cellular stress were increased, whereas specific components of chromosome segregation and DNA recombination/repair systems were decreased. CONCLUSIONS: Our study identifies proteomic changes at the subnuclear level that are associated with CRC and may be further investigated. This article is part of a Special Issue entitled: Biomarkers: A Proteomic Challenge.

Proteomic profiling of Mycobacterium tuberculosis identifies nutrient-starvation-responsive toxin-antitoxin systems.

In order to successfully enter the latent stage, Mycobacterium tuberculosis must adapt to conditions such as nutrient limitation and hypoxia. In vitro models that mimic latent infection are valuable tools for describing the changes in metabolism that occur when the bacterium exists in a non-growing form. We used two complementary proteomic approaches, label-free LC-MS/MS analysis and two-dimensional difference gel electrophoresis, to determine the proteome profile of extracellular proteins from M. tuberculosis cultured under nutrient starvation. Through the label-free LC-MS/MS analysis of fractionated samples, 1176 proteins were identified from culture filtrates of log phase and nutrient-starved cultures, and the protein levels of 230 proteins were increased in nutrient-starved culture filtrates, whereas those of 208 proteins were decreased. By means of Gene Ontology clustering analysis, significant differences in the overall metabolism during nutrient starvation were detected. Notably, members of the toxin-antitoxin systems were present in larger quantities in nutrient-starved cultures, supporting a role for these global modules as M. tuberculosis switches its metabolism into dormancy. Decreased abundance of proteins involved in amino acid and protein synthesis was apparent, as well as changes in the lipid metabolism. Further analysis of the dataset identified increased abundance of lipoproteins and decreased abundance of ESAT-6 family proteins. Results from the two-dimensional difference gel electrophoresis proteomics demonstrated overall agreement with the LC-MS/MS data and added complementary insights about protein degradation and modification.

Serum INSL3 measured by LC-MS/MS in pubertal girls and in girls with precocious puberty during GnRH agonist treatment.

Introduction: The peptide hormone Insulin-like Factor 3 (INSL3) is a biomarker of testicular Leydig cells in the male but is also expressed by the theca cells of the ovaries. With the advent of sensitive assays INSL3 can be quantified in female circulation, and we suggest that circulating INSL3 is a novel biomarker for pubertal development in girls. The aim of the study is to quantify INSL3 by LC-MS/MS in sera from normal girls during pubertal transition, and during gonadal suppression by GnRH agonist therapy in girls with central precocious puberty (CPP). Method: The sensitivity of an established LC-MS/MS-based method for serum INSL3 was improved by switching to a state-of-the-art triple quadruple mass spectrometer (Altis Plus, Thermo). Results: The limit of detection of the improved LC-MS/MS method for serum INSL3 was 0.01 ug/L (1.5 pM) and the inter-assay CV was < 12%. Serum INSL3 increased during the pubertal transition in healthy girls and changes correlated with the concomitant rise in other measured hormones. In some girls, but not all, INSL3, FSH, inhibin B and estradiol serum concentrations increased prior to first clinical signs of puberty. Serum INSL3 concentrations were increased at baseline in girls with CPP compared to prepubertal controls and decreased during treatment with GnRH agonist followed by a steep rise and normalization after cessation of treatment. Conclusion: The improved method allowed for quantification of INSL3 in longitudinally collected serum samples during pubertal transition in healthy girls as well as in girls with CPP before, during and after treatment with GnRH agonist. Future studies are needed to clarify if INSL3 in combination with other biomarkers enhances the predictive value of differentiating between premature thelarche and CPP.

Insulin-like Factor 3, Basal and Human Chorionic Gonadotropin-Stimulated Testosterone as Biomarkers to Predict the Effect of Testosterone Replacement in Testicular Cancer Survivors With Mild Leydig Cell Insufficiency.

INTRODUCTION: Mild Leydig cell insufficiency affects a substantial proportion of testicular cancer survivors. Previous studies have not shown a beneficial effect of testosterone replacement therapy, however, with a pronounced interindividual effect. Thus, biomarkers identifying the subgroups that might benefit are wanted. We aimed to determine if insulin-like factor 3 (INSL3), basal and human chorionic gonadotropin (hCG)-stimulated testosterone can predict the effect of testosterone replacement therapy in testicular cancer survivors with mild Leydig cell insufficiency. PATIENTS AND METHODS: We randomized adult testicular cancer survivors with mild Leydig cell insufficiency 1:1 to 12 months of transdermal testosterone replacement therapy (Tostran gel 2%) or placebo. INSL3, basal, and hCG-stimulated testosterone were measured at baseline. Outcomes (glucose, insulin, HbA1C, lipids, blood pressure, and body composition) were measured at baseline, 6 and 12 months. We applied a linear mixed-effect model comparing patients receiving testosterone with placebo in subgroups by biomarker. RESULTS: We included and randomized 69 patients between October 2016 and February 2018. Patients with INSL3 and hCG-stimulated testosterone concentrations below the median had a -1.7 kg (95% CI: -3.1, -0.4) and -2.0 kg (95% CI: -3.5, -0.6) change in fat mass after 12 months of testosterone replacement therapy compared with placebo. This was not the case in patients with INSL3 and hCG-stimulated testosterone above the median. We did not find any effect of these biomarkers on glucose, insulin, HbA1c, or lipids. CONCLUSION: Patients with INSL3 and hCG-stimulated testosterone concentrations below the median had decreased fat mass after 12 months of testosterone replacement therapy compared with placebo. It should be evaluated in larger trials if these biomarkers can be used as predictive markers identifying testicular cancer patients with mild Leydig cell insufficiency who might benefit from testosterone substitution.

The impact of acute SARS-CoV-2 on testicular function including insulin-like factor 3 (INSL3) in men with mild COVID-19: A longitudinal study.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may affect the male reproductive system as it uses angiotensin-converting enzyme (ACE)2, which is expressed in testicular tissue, as an entry point into the cell. Few studies have evaluated the long-term effects of mild coronavirus disease 2019 (COVID-19) on testicular function, and insulin-like factor 3 (INSL3) levels have not previously been assessed during acute SARS-CoV-2 infection. OBJECTIVES: The aim of the study was to assess the impact of acute SARS-CoV-2 infection on testicular function including INSL3 and the presence of SARS-CoV-2 RNA in semen in non-hospitalised men with mild COVID-19. MATERIALS AND METHODS: This longitudinal study included 36 non-hospitalised SARS-CoV-2-positive men (median age 29 years). Inclusion was within seven days following a positive SARS-CoV-2 reverse-transcription polymerase chain reaction test. Reproductive hormone levels, semen parameters, and the presence of SARS-CoV-2 RNA in oropharyngeal and semen samples were assessed during acute SARS-CoV-2 infection (baseline) and at three- and six-month follow-up. Wilcoxon matched-pair signed-rank (two samples) test was used to assess time-related alterations in reproductive hormone levels and semen parameters. RESULTS: Lower plasma testosterone (T) (total and calculated free (c-fT)) and higher luteinising hormone (LH) concentrations were observed during acute SARS-CoV-2 infection (baseline) compared to three- and six-month follow-up. Consequently, ratios of c-fT/LH were lower at baseline compared to three- and six-month follow-up (p < 0.001 and p = 0.003, respectively). Concomitantly, lower INSL3 concentrations were observed at baseline compared to three-month follow-up (p = 0.01). The total number of motile spermatozoa was also lower at baseline compared to six-month follow-up (p = 0.02). The alterations were detected irrespective of whether the men had experienced SARS-CoV-2-related fever episodes or not. No SARS-CoV-2 RNA was detected in semen at any time point. DISCUSSION AND CONCLUSION: This study showed a reduction in testicular function, which was for the first time confirmed by INSL3, in men mildly affected by SARS-CoV-2 infection. The risk of transmission of SARS-CoV-2 RNA via semen seems to be low. Febrile episodes may impact testicular function, but a direct effect of SARS-CoV-2 cannot be excluded.

Pituitary-testis axis dysfunction following adjuvant androgen deprivation therapy.

Men with high-risk, non-metastatic prostate cancer receive adjuvant androgen deprivation therapy (ADT) for at least 2 years according to Danish guidelines. It remains unclarified if patients regain the function of the pituitary-testis axis after cessation of ADT. Thus, we aimed to investigate the function of the pituitary-testis axis following adjuvant ADT. In this study, we included men who underwent external beam radiation therapy and ADT for high-risk prostate cancer. All patients underwent assessment of testosterone deficiency (TD) symptoms, full biochemical assessment of the pituitary-testis axis, and dynamic stimulatory tests of gonadotropin (gonadotropin-releasing hormone (GnRH) test) and testosterone production (human chorionic gonadotrophin (hCG) test). Patients were diagnosed with TD based on a combination of TD symptoms and testosterone below age-specific reference ranges. TD was characterized as primary, secondary, or mixed based on serum gonadotropins and stimulatory tests. We found that among the 51 patients included in the study, the median time on ADT was 3.2 years and median time since ADT cessation was 3.8 years. Twenty-eight patients were diagnosed with TD; 10 had primary TD (testicular dysfunction), 11 secondary TD (pituitary dysfunction), and 7 mixed TD (combined pituitary and testicular dysfunction). An inadequate testosterone response to hCG stimulation was shown in 42 patients, whereas only 11 patients had a subnormal gonadotropin response to GnRH. We conclude that persistent TD is a common long-term consequence of adjuvant ADT in prostate cancer survivors, equally distributed between pituitary and testicular dysfunction. The study emphasizes the necessity for systematic follow-up of full pituitary-testis axis function in patients receiving adjuvant ADT.

Serum Insulin-like Factor 3, Testosterone, and LH in Experimental and Therapeutic Testicular Suppression.

BACKGROUND: Serum insulin-like factor 3 (INSL3) is a Leydig cell biomarker, but little is known about the circulating concentration of INSL3 during hypothalamus-pituitary-testicular suppression. AIM: To study the concomitant changes in serum concentrations of INSL3, testosterone, and LH during experimental and therapeutic testicular suppression. METHODS: We included serum samples from 3 different cohorts comprising subjects before and after testicular suppression: (1) 6 healthy young men who were treated with androgens (Sustanon, Aspen Pharma, Dublin, Ireland); 2) 10 transgender girls (male sex assigned at birth) who were treated with 3-monthly GnRH agonist injections (Leuprorelinacetat, Abacus Medicine, Copenhagen, Denmark); and (3) 55 patients with prostate cancer who were randomized to surgical castration (bilateral subcapsular orchiectomy) or treatment with GnRH agonist (Triptorelin, Ipsen Pharma, Kista, Sweden). Serum INSL3 and testosterone concentrations were quantified in stored serum samples using validated liquid chromatography-tandem mass spectrometry methodologies, and LH was measured by an ultrasensitive immunoassay. RESULTS: The circulating concentrations of INSL3, testosterone, and LH decreased during experimental testicular suppression in healthy young men by Sustanon injections and subsequently returned to baseline levels after release of suppression. All 3 hormones decreased during therapeutic hormonal hypothalamus-pituitary-testicular suppression in transgender girls and in patients with prostate cancer. CONCLUSION: INSL3 resembles testosterone as a sensitive marker of testicular suppression and reflects Leydig cell function, also during exposure to exogenous testosterone. Serum INSL3 measurements may complement testosterone as a Leydig cell marker in male reproductive disorders, during therapeutic testicular suppression as well as in surveillance of illicit use of androgens.

Urinary concentration of phthalates and bisphenol A during minipuberty is associated with reproductive hormone concentrations in infant boys.

BACKGROUND: The transient postnatal activation of the hypothalamic-pituitary-gonadal hormone axis is termed minipuberty and considered an important developmental period, which is highly sensitive to endocrine disruption. Here, we explore exposure-outcome associations during minipuberty between concentrations of potentially endocrine disrupting chemicals (EDCs) in urine of infant boys and their serum reproductive hormone concentrations. METHODS: In total, 36 boys participating in the COPENHAGEN Minipuberty Study had data available for both urine biomarkers of target endocrine disrupting chemicals and reproductive hormones in serum from samples collected on the same day. Serum concentrations of reproductive hormones were measured by immunoassays or by LC-MS/MS. Urinary concentrations of metabolites of 39 non-persisting chemicals, including phthalates and phenolic compounds, were measured by LC-MS/MS. Nineteen chemicals had concentrations above the limit of detection in ≥50% of children and were included in data analysis. Associations of urinary phthalate metabolite and phenol concentrations (in tertiles) with hormone outcomes (age- and sex-specific SD-scores) were analysed by linear regression. Primarily, we focused on the EU regulated phthalates; butylbenzyl phthalate (BBzP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di-(2-ethylhexyl) phthalate (DEHP) as well as bisphenol A (BPA). Urinary metabolites of DiBP, DnBP and DEHP were summed and expressed as ∑DiBPm, ∑DnBPm and ∑DEHPm. RESULTS: Compared to boys in the lowest ∑DnBPm tertile, urinary concentration of ∑DnBPm was associated with concurrent higher luteinizing hormone (LH) and anti-Müllerian hormone (AMH) SD-scores as well as lower testosterone/LH ratio in boys in the middle ∑DnBPm tertile (estimates (CI 95%) 0.79 (0.04; 1.54), 0.91 (0.13; 1.68), and -0.88 (-1.58;-0.19), respectively). Further, higher insulin-like peptide 3 (INSL3) SD-scores and lower DHEAS SD-score in boys in the highest ∑DnBPm tertile (0.91 (0.12; 1.70) and -0.85 (-1.51;-0.18), respectively) were observed. In addition, boys in the middle and highest ∑DEHPm tertile had higher LH (1.07 (0.35; 1.79) and 0.71 (-0.01; 1.43), respectively) and in the highest ∑DEHPm tertile also higher AMH (0.85 (0.10; 1.61)) concentration SD-scores, respectively. Boys in the highest BPA tertile had significantly higher AMH and lower DHEAS concentration compared to boys in the lowest BPA tertile (1.28 (0.54; 2.02) and -0.73 (-1.45; -0.01)), respectively. DISCUSSION: Our findings indicate that exposure to chemicals with known or suspected endocrine disrupting potential, especially the EU-regulated DnBP, DEHP and BPA, may modify male reproductive hormone concentrations in infant boys suggesting that minipuberty is a critical window sensitive to endocrine disruption.

Reduced serum concentrations of biomarkers reflecting Leydig and Sertoli cell function in male patients with congenital adrenal hyperplasia.

Congenital adrenal hyperplasia (CAH) is a recessive condition that affects the adrenal glands. Despite life-long replacement therapy with glucocorticoids and mineralocorticoids, adult patients with CAH often experience impaired gonadal function. In pubertal boys and in men with CAH, circulating testosterone is produced by the adrenal glands as well as the testicular, steroidogenic cells. In this European two-center study, we evaluated the function of Leydig and Sertoli cells in 61 boys and men with CAH, primarily due to 21-hydroxylase deficiency. Despite conventional hormone replacement therapy, our results indicated a significant reduction in serum concentrations of both Leydig cell-derived hormones (i.e. insulin-like factor 3 (INSL3) and testosterone) and Sertoli cell-derived hormones (i.e. inhibin B and anti-Müllerian hormone) in adult males with CAH. Serum concentrations of INSL3 were particularly reduced in those with testicular adrenal rest tumors. To our knowledge, this is the first study to evaluate circulating INSL3 as a candidate biomarker to monitor Leydig cell function in patients with CAH.

Gel-based proteomics of liver cancer progression in rat.

A significant challenge in proteomics biomarker research is to identify the changes that are of highest diagnostic interest, among the many unspecific aberrations associated with disease burden and inflammation. In the present study liver tissue specimens (n=18) from six experimental stages were collected from the resistant hepatocyte (RH) rat model of liver cancer and analyzed by 2D DIGE. The study included triplicates of regenerating liver, control "sham-operated" liver, three distinct premalignant stages and hepatomas. Out of 81 identified proteins two-thirds were differentially abundant in rat hepatomas compared to control rat liver and, secondly, the majority of proteins were also changed in precursor stages. This underscores the importance of adequate control samples in explorative cancer biomarker research. We confirm several proteomic changes previously identified in human hepatocellular carcinoma (HCC) and we identify novel candidate proteomic aberrations for further analysis in human HCC. In particular, increased levels of HSP70, HSP90, AKR1B1, AKR7A3, GCLM, ANXA5, VDBP, RGN and SULT1E1 were associated specifically with rat hepatomas, or with liver cancer progression in rat. In addition, we examine an integrated gel-based workflow for analysis of protein post-translational modifications (PTMs) and microtubule-association. We highlight differential PTM and localization of HSP60 as an interesting target for further analysis in liver cancer.

Subnuclear proteomics in colorectal cancer: identification of proteins enriched in the nuclear matrix fraction and regulation in adenoma to carcinoma progression.

Abnormalities in nuclear phenotype and chromosome structure are key features of cancer cells. Investigation of the protein determinants of nuclear subfractions in cancer may yield molecular insights into aberrant chromosome function and chromatin organization and in addition may yield biomarkers for early cancer detection. Here we evaluate a proteomics work flow for profiling protein constituents in subnuclear domains in colorectal cancer tissues and apply this work flow to a comparative analysis of the nuclear matrix fraction in colorectal adenoma and carcinoma tissue samples. First, we established the reproducibility of the entire work flow. In a reproducibility analysis of three nuclear matrix fractions independently isolated from the same colon tumor homogenate, 889 of 1,047 proteins (85%) were reproducibly identified at high confidence (minimally two peptides per protein at 99% confidence interval at the protein level) with an average coefficient of variance for the number of normalized spectral counts per protein of 30%. This indicates a good reproducibility of the entire work flow from biochemical isolation to nano-LC-MS/MS analysis. Second, using spectral counting combined with statistics, we identified proteins that are significantly enriched in the nuclear matrix fraction relative to two earlier fractions (the chromatin-binding and intermediate filament fractions) isolated from six colorectal tissue samples. The total data set contained 2,059 non-redundant proteins. Gene ontology mining and protein network analysis of nuclear matrix-enriched proteins revealed enrichment for proteins implicated in "RNA processing" and "mRNA metabolic process." Finally, an explorative comparison of the nuclear matrix proteome in colorectal adenoma and carcinoma tissues revealed many proteins previously implicated in oncogenesis as well as new candidates. A subset of these differentially expressed proteins also exhibited a corresponding change at the mRNA level. Together, the results show that subnuclear proteomics of tumor tissue is feasible and a promising avenue for exploring oncogenesis.

Dynamic Changes of Reproductive Hormones in Male Minipuberty: Temporal Dissociation of Leydig and Sertoli Cell Activity.

CONTEXT: The male hypothalamic-pituitary-gonadal (HPG) axis is transiently active during the first months of life with surging serum concentrations of reproductive hormones. This period, termed minipuberty, appears to be essential for priming testicular function. Despite the central role for male reproductive function, longitudinal data on HPG axis activation in infancy is sparse. OBJECTIVE: To explore the dynamics of HPG hormone activity in healthy male infants, to assess the association of HPG axis activity and testicular volume, and to establish reference curves for serum levels of reproductive hormones. DESIGN: Prospective, longitudinal birth cohort (the COPENHAGEN Minipuberty Study, 2016-2018, 1-year follow-up). SETTING: Population-based. PATIENTS OR OTHER PARTICIPANTS: Healthy, male, term, singleton newborns were followed from birth on with repeated clinical examinations including blood sampling during a 1-year follow-up. A total of 128 boys contributed to this study, while 119 participated in the postnatal follow-up. MAIN OUTCOME MEASURES: Serum reproductive hormone concentrations and testicular volume. RESULTS: Reproductive hormone concentrations showed marked dynamics during the first 6 months of age. Gonadotropins, total testosterone, and insulin-like factor 3 peaked at around 1 month of age. Inhibin B, anti-Müllerian hormone, and testicular volume peaked at around 4 to 5 months. Correlations largely recapitulated typical HPG axis pathways but also differed significantly from adult men. CONCLUSIONS: We demonstrate a temporal dissociation of Leydig and Sertoli cell activity during male minipuberty and provide reference curves for reproductive hormones.

Reproductive Markers of Testicular Function and Size During Puberty in Boys With and Without a History of Cryptorchidism.

CONTEXT: Longitudinal data on levels of hypothalamic-pituitary-gonadal axis hormones and insulin-like growth factor I (IGF-I) during puberty in boys with a history of cryptorchidism are largely missing. OBJECTIVE: We aimed to compare pubertal hormone levels between boys with a history of congenital cryptorchidism who experienced spontaneous testicular descent or underwent orchiopexy and boys without a history of cryptorchidism. METHODS: This was a nested case-control study within a population-based birth cohort, with a prospective, longitudinal pubertal follow-up every 6 months (2005 to 2019). Participants were 109 Finnish boys, including boys with a history of unilateral cryptorchidism who underwent orchiopexy (n = 15), unilateral cryptorchidism who had spontaneous testicular descent (n = 15), bilateral cryptorchidism who underwent orchiopexy (n = 9), bilateral cryptorchidism who had spontaneous testicular descent (n = 7), and controls (n = 63). Serum reproductive hormone levels and testicular volumes were measured. RESULTS: From around onset of puberty, boys with bilateral cryptorchidism who underwent orchiopexy had significantly higher follicle-stimulating hormone (FSH) and lower inhibin B levels than controls. Boys with unilateral cryptorchidism who underwent orchiopexy had significantly higher FSH than controls, whereas inhibin B levels were similar. Testosterone, luteinizing hormone, insulin-like factor 3, and IGF-I were generally similar between groups. Testicular volume of boys with unilateral or bilateral cryptorchidism who underwent orchiopexy was smaller than that of the controls from 1 year after pubertal onset (P < 0.05). CONCLUSION: Cryptorchid boys, particularly those with bilateral cryptorchidism who underwent orchiopexy, had altered levels of serum biomarkers of Sertoli cells and germ cells and smaller testicular volumes compared with controls.

Endocrine outcome and seminal parameters in young adult men born with hypospadias: A cross-sectional cohort study.

BACKGROUND: Hypospadias affects around 1/200 newborn males. Intrauterine testicular dysfunction may underlie a subset of cases. The long-term endocrine and reproductive outcomes in these men remain largely unknown. METHODS: Cross-sectional study in Ghent and Vienna University Hospitals to assess the endocrine and seminal parameters of young adult men (16-21 years) born with non-syndromic hypospadias (NSH) (n = 193) compared to healthy typical males (n = 50). Assessments included physical exam, semen analysis, hormone assays and exome-based gene panel analysis (474 genes). FINDINGS: All participants had experienced a spontaneous puberty, in spite of higher LH and INSL3 levels than typical males. Oligo- or azoospermia was observed in 32/172 (18·6%; 99%-CI: 12·2-27·4%) of NSH men; but in 5/16 (31·3%; 99%-CI: 11·1;62·4%) of complex NSH men and in 13/22 (59·1%; 99%-CI: 33·2-80·7%) of those born small for gestational age (SGA). No (likely) pathogenic coding variants were found in the investigated genes. Suboptimal statural growth affected 8/23 (34·8%; 99%-CI: 15·4-61·0%) of men born SGA with NSH. INTERPRETATION: Spermatogenesis is significantly compromised in NSH men, especially in those born SGA or those with complex NSH. Long-term andrological follow-up is recommended, including end-pubertal semen analysis. No clear monogenic causes could be demonstrated in our cohort even in proximal or complex NSH. Being born SGA with NSH is frequently associated with poor catch-up growth, requiring growth hormone therapy in some. FUNDING: Research grants from the European Society of Paediatric Endocrinology, the Belgian Society of Pediatrics, the Belgian Society of Pediatric Endocrinology and Diabetology and the Research Foundation Flanders (FWO).

Serum Insulin-like Factor 3 Levels Are Reduced in Former Androgen Users, Suggesting Impaired Leydig Cell Capacity.

CONTEXT: Illicit use of anabolic androgenic steroids (AAS) is frequently observed in men and is associated with subsequent testosterone deficiency although the long-term effect on gonadal function is still unclear. Serum insulin-like factor 3 (INSL3) has been suggested to be a superior biomarker of Leydig cell secretory capacity compared to testosterone. OBJECTIVE: This study aimed to investigate serum INSL3 concentrations in AAS users. METHODS: This community-based, cross-sectional study included men aged 18 to 50 years, involved in recreational strength training and allocated to 1 of 3 groups: never-AAS users as controls (n = 44), current (n = 46), or former AAS users (n = 42) with an average duration since AAS cessation of 32 (23 ; 45) months. RESULTS: Serum INSL3 was lower in current AAS users and former AAS users than in controls, median (interquartile range), 0.04 µg/L (nondetectable [ND]-0.07 µg/L) and 0.39 µg/L (0.24-0.62 µg/L) vs 0.59 µg/L (0.45-0.72 µg/L), P less than .001. Former AAS users exhibited lower serum INSL3 levels than controls in a multivariable linear regression even after adjusting for serum total testosterone (TT) and other relevant confounders, (B) (95% CI), -0.16 µg/L (95% CI, -0.29 to -0.04 µg/L), P equal to .011. INSL3 and TT were not associated in the model, P equal to .821. Longer accumulated AAS duration (log2) was associated with lower serum INSL3 in former AAS users, (B) (95% CI), -0.08 (95% CI, -0.14 to -0.01), P equal to .022. Serum INSL3, but not inhibin B or testosterone, was associated with testicular size in a multivariate linear regression, (B) (95% CI); 4.7 (95% CI, 0.5 to 8.9), P equal to .030. CONCLUSION: Serum INSL3 is reduced years following AAS cessation in men, independently of testosterone, suggesting persistently impaired Leydig cell capacity.

Serum Concentrations and Gonadal Expression of INSL3 in Eighteen Males With 45,X/46,XY Mosaicism.

Objective: Insulin-like factor 3 (INSL3) is produced in the testes and has been proposed as a circulating biomarker of Leydig cell capacity, but remains undescribed in 45,X/46,XY mosaicism. The aim was to examine serum concentrations and gonadal expression of INSL3 in 45,X/46,XY mosaicism. Methods: Retrospectively collected data from medical records, gonadal tissue samples, and prospectively analyzed serum samples from eighteen male patients with 45,X/46,XY mosaicism (one prepubertal, four testosterone-treated, 13 untreated) were included. Biochemical, clinical, and histological outcomes were evaluated according to serum INSL3 concentrations, quantified by LC-MS/MS methodology, and gonadal INSL3 immunohistochemical expression. Results: Serum INSL3 concentrations spanned from below to above the reference range. In untreated patients, the median serum INSL3 SD score was -0.80 (IQR: -1.65 to 0.55) and no significant difference was observed between INSL3 and testosterone. There was no clear association between serum INSL3 and External Genitalia Score at diagnosis, spontaneous puberty, or sperm concentration. INSL3 and CYP11A1 expression overlapped, except for less pronounced INSL3 expression in areas with severe Leydig cell hyperplasia. No other apparent links between INSL3 expression and histological outcomes were observed. Conclusions: In this pilot study, serum INSL3 concentrations ranged and seemed independent of other reproductive hormones and clinical features in males with 45,X/46,XY mosaicism. Discordant expression of INSL3 and CYP11A1 may explain low INSL3 and normal testosterone concentrations in some patients. Further studies are needed to elucidate the divergence between serum INSL3 and testosterone and the potential clinical use of INSL3.