Sertoli Cell Wt1 Regulates Peritubular Myoid Cell and Fetal Leydig Cell Differentiation during Fetal Testis Development

Applications of single-cell RNA sequencing in spermatogenesis and molecular evolution

Spermatogenic cell heterogeneity is determined by the complex process of spermatogenesis differentiation. However, effectively revealing the regulatory mechanisms underlying mammalian spermatogenic cell development and differentiation via traditional methods is difficult. Advances in technology have led to the emergence of many single-cell transcriptome sequencing protocols, which have partially addressed these challenges. In this review, we detail the principles of 10x Genomics technology and summarize the methods for downstream analysis of single-cell transcriptome sequencing data. Furthermore, we explore the role of single-cell transcriptome sequencing in revealing the heterogeneity of testicular ecological niche cells, delineating the establishment and disruption of testicular immune homeostasis during human spermatogenesis, investigating abnormal spermatogenesis in humans, and, ultimately, elucidating the molecular evolution of mammalian spermatogenesis.

Effect of platelet rich plasma versus melatonin on testicular injury induced by Busulfan in adult albino rats: a histological and immunohistochemical study

This study was done to estimate the testicular histological alterations induced by Busulfan (BUS) and compare the possible protective effects of melatonin (MT) and platelet rich plasma (PRP) in a rat model. Sixty-four male rats were dispersed into: control group, BUS group, melatonin group, and PRP group. Blood samples were processed for biochemical analysis. Tissue specimens were managed for light and electron microscopic studies. Immunohistochemical expression of vimentin and proliferating cell nuclear antigen (PCNA) was performed. Busulfan induced severe testicular damage in all studied methodologies. It showed a statistically significant decrease in serum testosterone and elevation of MDA when compared to the control group. Abnormal testicular cytostructures suggesting defective spermatogenesis were observed: distorted seminiferous tubules, deformed spermatogenic cells, low germinal epithelium height, few mature spermatozoa, and also deformed barrier. Vimentin and PCNA expressions were reduced. Ultrastructurally, Sertoli cells and the blood testis barrier were deformed, spermatogenic cells were affected, and mature spermatozoa were few and showed abnormal structure. Both melatonin and PRP induced improvement in all the previous parameters and restoration of spermatogenesis as confirmed by improvement of Johnsen's score from 2.6 ± .74 to 7.6 ± .92. In conclusion, melatonin and PRP have equal potential to ameliorate the testicular toxicity of BUS. Melatonin can provide a better noninvasive way to combat BUS induced testicular injury.

Unveiling the roles of Sertoli cells lineage differentiation in reproductive development and disorders: a review

In mammals, gonadal somatic cell lineage differentiation determines the development of the bipotential gonad into either the ovary or testis. Sertoli cells, the only somatic cells in the spermatogenic tubules, support spermatogenesis during gonadal development. During embryonic Sertoli cell lineage differentiation, relevant genes, including WT1, GATA4, SRY, SOX9, AMH, PTGDS, SF1, and DMRT1, are expressed at specific times and in specific locations to ensure the correct differentiation of the embryo toward the male phenotype. The dysregulated development of Sertoli cells leads to gonadal malformations and male fertility disorders. Nevertheless, the molecular pathways underlying the embryonic origin of Sertoli cells remain elusive. By reviewing recent advances in research on embryonic Sertoli cell genesis and its key regulators, this review provides novel insights into sex determination in male mammals as well as the molecular mechanisms underlying the genealogical differentiation of Sertoli cells in the male reproductive ridge.

Bovine adipose tissue-derived mesenchymal stem cells self-assemble with testicular cells and integrates and modifies the structure of a testicular organoids

Mesenchymal stem cells (MSC) display self-renewal and mesodermal differentiation potentials. These characteristics make them potentially useful for in vitro derivation of gametes, which may constitute experimental therapies for human and animal reproduction. Organoids provide a spatial support and may simulate a cellular niche for in vitro studies. In this study, we aimed at evaluating the potential integration of fetal bovine MSCs derived from adipose tissue (AT-MSCs) in testicular organoids (TOs), their spatial distribution with testicular cells during TO formation and their potential for germ cell differentiation. TOs were developed using Leydig, Sertoli, and peritubular myoid cells that were previously isolated from bovine testes (n = 6). Thereafter, TOs were characterized using immunofluorescence and Q-PCR to detect testicular cell-specific markers. AT-MSCs were labeled with PKH26 and then cultured with testicular cells at a concentration of 1 × 106 cells per well in Ultra Low Attachment U-shape bottom (ULA) plates. TOs formed by testicular cells and AT-MSCs (TOs + AT-MSCs) maintained a rounded structure throughout the 28-day culture period and did not show significant differences in their diameters. Conversely, control TOs exhibited a compact structure until day 7 of culture, while on day 28 they displayed cellular extensions around their structure. Control TOs had greater (P < 0.05) diameters compared to TOs + AT-MSCs. AT-MSCs induced an increase in proportion of Leydig and peritubular myoid cells in TOs + AT-MSCs; however, did not induce changes in the overall gene expression of testicular cell-specific markers. STAR immunolabelling detected Leydig cells that migrated from the central area to the periphery and formed brunches in control TOs. However, in TOs + AT-MSCs, Leydig cells formed a compact peripheral layer. Sertoli cells immunodetected using WT1 marker were observed within the central area forming clusters of cells in TOs + AT-MSCs. The expression of COL1A associated to peritubular myoids cells was restricted to the central region in TOs + AT-MSCs. Thus, during a 28-day culture period, fetal bovine AT-MSCs integrated and modified the structure of the TOs, by restricting formation of branches, limiting the overall increase in diameters and increasing the proportions of Leydig and peritubular myoid cells. AT-MSCs also induced a reorganization of testicular cells, changing their distribution and particularly the location of Leydig cells.

Evaluating the histomorphological and biochemical changes induced by Tributyltin Chloride on pituitary-testicular axis of adult albino rats and the possible ameliorative role of hesperidin

This study was performed to explore in detail the toxic effects of Tributyltin Chloride (TBT) on the pituitary-testicular axis and the possible amelioration with Hesperidin. Seventy-two adult male albino rats were divided into four groups: Control group (I), TBT-treated group (II), TBT+Hesperidin group (III), and Recovery group (IV). Body and testicular weights were measured. Blood samples were taken to estimate serum levels of testosterone, FSH and LH hormones by enzyme-linked immunosorbent assay (ELISA). Malondialdehyde (MDA) level was measured in testes homogenates. Tissue samples from the pituitary glands and testes were processed for light, electron microscope examination, and immunohistochemical detection of anti-FSH, and Ki67 proteins. Results showed a statistically significant decrease in testicular weight, serum testosterone, FSH and LH levels and a significant increase in tissue MDA in the TBT group when compared to the control group. TBT treatment caused severe histopathological changes with decreased area percent of PAS-stained basophils, and anti FSH immuno-stained gonadotrophs in the pituitary gland. The testes of group II also showed marked tissue damage, cell loss with decreased epithelial height and decreased number of proliferating spermatogenic cells. Hesperidin supplementation with TBT proved significant amelioration of the previously mentioned parameters in both glands which could improve male fertility. In conclusion: The flavonoid Hesperidin has the potential to protect against the reproductive damage induced by TBT in susceptible individuals.

Human spermatogonial stem cells and their niche in male (in)fertility: novel concepts from single-cell RNA-sequencing

The amount of single-cell RNA-sequencing (scRNA-seq) data produced in the field of human male reproduction has steadily increased. Transcriptional profiles of thousands of testicular cells have been generated covering the human neonatal, prepubertal, pubertal and adult period as well as different types of male infertility; the latter include non-obstructive azoospermia, cryptozoospermia, Klinefelter syndrome and azoospermia factor deletions. In this review, we provide an overview of transcriptional changes in different testicular subpopulations during postnatal development and in cases of male infertility. Moreover, we review novel concepts regarding the existence of spermatogonial and somatic cell subtypes as well as their crosstalk and provide corresponding marker genes to facilitate their identification. We discuss the potential clinical implications of scRNA-seq findings, the need for spatial information and the necessity to corroborate findings by exploring other levels of regulation, including at the epigenetic or protein level.

Reproductive development of male rats exposed in utero to stress and/or sertraline

Despite increased prescription of sertraline during pregnancy, little is known about its action on reproductive development. Therefore, the present study aimed to investigate the impact that stress, associated or not with sertraline, causes on the reproductive development of male rats. Pregnant Wistar rats were divided into 4 groups (n = 16/group): CO - received filtered water; SE - received 20 mg/kg sertraline; ST - submitted to restraint stress and received filtered water; SS - submitted to restraint stress and received sertraline. The treatment was carried out from gestational days (GD) 13 to 20. The animals were euthanized on GD 20 (n = 8/group), postnatal day (PND) 45 (n = 8/group) and PND 110 (n = 8/group). The testes and epididymis were analyzed histologically, and immunohistochemistry was performed on the testes by proliferating cell nuclear antigen (PCNA) and the Wilms tumor protein (Wt1). Sperm quality was also analyzed on PND 110. The evolution of body weight, anogenital distance (AGD), and puberty installation day were also verified. Statistical analysis: Two-way ANOVA or Kruskal-Wallis test (p ≤ 0.05). Fetal testes presented a large number of acidophilic cells in the sertraline-exposed groups. The SS group also showed a decrease in the nuclear volume of Leydig cells. This same group showed low expression of PCNA and Wt1, decreased weight of the testes and epididymis, lower AGD, and delayed puberty installation. The adulthood groups exposed to sertraline presented alterations in sperm morphology and motility. The results demonstrated that prenatal exposure to sertraline compromises the development of the rat reproductive system.

Coenzyme Q10 alleviates testicular endocrine and spermatogenic dysfunction induced by high-fat diet in male Wistar rats: Role of adipokines, oxidative stress and MAPK/ERK/JNK pathway

The current study investigated the possible protective effects of Coenzyme Q₁₀ (Co Q₁₀ ) on rat model of high-fat diet (HFD) induced testicular dysfunction. Thirty male Wistar rats were allocated randomly into three groups: control, HFD, HFD + Co Q₁₀ (75 mg/kg/day) groups. Animals were sacrificed after 3 months and epididymal sperm suspension, blood, and testes were collected for further analysis. In comparison to the untreated HFD group, the Co Q₁₀ treated group revealed significantly increased serum testosterone, adiponectin levels, and decreased LH, FSH, and leptin levels. In addition, HFD resulted in significant increase in testicular oxidative stress (increased MDA, iNOS, NO, XO & decreased catalase, SOD, GSH) and inflammation (increased pJNK/JNK, pERK/ERK, and p-p38MAPK/MAPK), while Co Q₁₀ was effective to ameliorate these changes. In addition, Co Q₁₀ significantly increased sperm count, motility and viability that were markedly deteriorated by HFD. Regarding testicular ultrastructure, seminiferous tubular diameter and epithelium height were reduced in HFD group and Co Q₁₀ significantly improved these testicular changes. Finally, a significant reduction in spermatogenic cell proliferation was detected by PCNA fluorescent expression and Co Q₁₀ significantly reversed this change. In summary, our results indicated that Co Q₁₀ could suppress testicular dysfunction produced by HFD. This protective effect could be attributed to its antioxidant, anti-inflammatory properties and to its effect on adipokines and spermatogenic cell proliferation. So, Co Q₁₀ may be a promising food supplement to protect against testicular dysfunction induced by HFD.

Small-Molecule-Driven Direct Reprogramming of Fibroblasts into Functional Sertoli-Like Cells as a Model for Male Reproductive Toxicology

Sertoli cells (SCs) are vital to providing morphological and nutritional support for spermatogenesis. Defects in SCs often lead to infertility. SCs transplantation is a promising potential strategy to compensate for SC dysfunction. However, isolation of SCs from testes is impractical due to obvious and ethical limitations. Here, a molecular cocktail is identified comprising of pan-BET family inhibitor (I-BET151), retinoic acid, and riluzole that enables the efficient conversion of fibroblasts into functional Sertoli-like cells (CiSCs). The gene expression profiles of CiSCs resemble those of mature SCs and exhibit functional properties such as the formation of testicular seminiferous tubules, engulfment of apoptotic sperms, supporting the survival of germ cells, and suppressing proliferation of primary lymphocytes in vitro. Moreover, CiSCs are sensitive to toxic substances, making them an alternative model to study the deleterious effects of toxicants on SCs. The study provides an efficient approach to reprogram fibroblasts into functional SCs by using pure chemical compounds.

Comparison of miRNA and mRNA Expression in Sika Deer Testes With Age

To elucidate the complex physiological process of testis development and spermatogenesis in Sika deer, this study evaluated the changes of miRNA and mRNA profiles in the four developmental stages of testis in the juvenile (1-year-old), adolescence (3-year-old), adult (5-year-old), and aged (10-year-old) stages. The results showed that a total of 198 mature, 66 novel miRNAs, and 23,558 differentially expressed (DE) unigenes were obtained; 14,918 (8,413 up and 6,505 down), 4,988 (2,453 up and 2,535 down), and 5,681 (2,929 up and 2,752 down) DE unigenes, as well as 88 (43 up and 45 down), 102 (44 up and 58 down), and 54 (18 up and 36 down) DE miRNAs were identified in 3- vs. 1-, 5- vs. 3-, and 10- vs. 5-year-old testes, respectively. By integrating miRNA and mRNA expression profiles, we predicted 10,790 mRNA-mRNA and 69,883 miRNA-mRNA interaction sites. The target genes were enriched by GO and KEGG pathways to obtain DE mRNA (IGF1R, ALKBH5, Piwil, HIF1A, BRDT, etc.) and DE miRNA (miR-140, miR-145, miR-7, miR-26a, etc.), which play an important role in testis development and spermatogenesis. The data show that DE miRNAs could regulate testis developmental and spermatogenesis through signaling pathways, including the MAPK signaling pathway, p53 signaling pathway, PI3K-Akt signaling pathway, Hippo signaling pathway, etc. miR-140 was confirmed to directly target mutant IGF1R-3'UTR by the Luciferase reporter assays. This study provides a useful resource for future studies on the role of miRNA regulation in testis development and spermatogenesis.

Tle4z1 Facilitate the Male Sexual Differentiation of Chicken Embryos

Background

Sex differentiation is a complex and precisely regulated process by multiple genes in chicken. However, it is still unclear on the key genes of sex differentiation.

Objective

To explore the function of Tle4z1 screened by RNA-seq sequencing on sex differentiation during the development of chicken embryos.

Methods

Tle4z1 was differentially expressed from the RNA-seq of ESCs and PGCs in male and female chickens. Then, we established an effective method to overexpression or knocking down the expression of Tle4z1 in ovo and in vitro, respectively. Histomorphological observation, qRT-PCR and ELISA were applied to detect the function of Tle4z1 in the process of male sex differentiation by injecting vectors into embryos at day 0.

Results

It showed that Tle4z1 has significant male preference in embryonic day 4.5, such phenomenon persisted during the growth period of chicken embryos. Morphological observation results showed that the gonads on both sides of genetic male (ZZ) embryos with Tle4z1 knocking down developed asymmetrically, the gonadal cortex became thicker showing the typical characteristics of genetic female (ZW) gonads. Furthermore, the expression of Cyp19a1, which dominates female differentiation, was significantly increased, while the expression of male marker genes Dmrt1, Sox9, WT1 and AR was significantly downregulated. In addition, the concentration of testosterone also significantly decreased, which was positively correlated with the expression of Tle4z1 (P < 0.01). Conversely, the ZW embryo showed defeminized development when Tle4z1 was overexpressed.

Conclusion

We prove that the Tle4z1 is a novel gene through the male sexual differentiation via gene regulation process and synthesis of testosterone, which construct the basis for understanding the molecular mechanism of sex differentiation in chickens.

Restoring Impaired Fertility Through Diet: Observations of Switching From High-Fat Diet During Puberty to Normal Diet in Adulthood Among Obese Male Mice

BACKGROUND

Obesity is associated with a decrease in testicular function, yet the effects and mechanisms relative to different stages of sexual development remain unclear. The aim of this study is to determine whether high-fat diet-induced obesity impairs male fertility during puberty and in adulthood, and to ascertain its underlying mechanisms. This study aims to further reveal whether restoring to a normal diet can improve impaired fertility.

METHODS

Male mice were divided into 6 groups: the group N and H exposed to a normal diet or high-fat diet during puberty. The group NN or NH were further maintained a normal diet or exposed to high-fat diet in adulthood, the group HH or HN were further maintained high-fat diet or switched to normal diet in adulthood. Metabolic parameters, fertility parameters, testicular function parameters, TUNEL staining and testicular function-related proteins were evaluated, respectively.

RESULTS

The fertility of the mice in the high-fat diet group was impaired, which validated by declines in pregnancy rates and litter weight loss. Further analysis demonstrated the increased level of oxidative stress, the increased number of spermatogenic cell apoptosis and decreased number of sperm and decreased acrosome integrity. The expression of steroidogenic acute regulatory (StAR) and spermatogenesis related proteins (WT-1) decreased. Fertility among the HN group recovered, accompanied by the recovery of metabolism, fertility and testicular function parameters, StAR and WT-1 expression.

CONCLUSIONS

The findings suggest that high-fat diet-induced obesity impairs male fertility during puberty and in adulthood. The loss of acrosome integrity, the increase of oxidative stress, the increase of cells apoptosis and the down-regulation of StAR and WT-1 may be the underlying mechanisms. Switching from high-fat diets during puberty to normal diets in adulthood can improve male fertility.

Histopathological Findings of Testicular Tissue Following Cadmium Toxicity in Rats

Background & Objective:

Reproductive toxicity of cadmium (Cd) as an environmental toxicant has been proved in animals and humans. Exposure to Cd impairs testes organs and can reduce male fertility. The present study was designed to investigate the spectrum of histopathological changes in testicular tissue focusing on Sertoli cells in rats following Cd intoxication.

Methods:

In the present experiment, acute testicular toxicity was induced by an intraperitoneal injection of 1.2 mg/kg CdCl₂ to the animals in the test group, while the control group received normal saline. After 52 days, the animals were euthanized, and testicular tissue was stained by Hematoxylin and Eosin. In addition, immunohistochemical staining was performed on Sertoli cells for Wilms' Tumor, Melan-A, and CD99 to evaluate histopathological changes.

Results:

Cd caused significant alterations in seminiferous tubules with varying effects on the patterns of spermatozoa production. These histopathological changes were significantly higher in the Cd group, compared to the control group.

Conclusion:

The Cd-induced stepwise spectrum changes included sloughing, disorganization, hypospermatogenesis, spermatic cell arrest, germ cell hypoplasia, Sertoli cell-only pattern, fibro-hyalinized seminiferous tubules, and calcification. Sertoli cells accumulated and created multinucleated giant cells in the seminiferous tubules during the atrophic process, which could be dependent upon Sertoli cells viability and function.

Distinctive functioning of STARD1 in the fetal Leydig cells compared to adult Leydig and adrenal cells. Impact of Hedgehog signaling via the primary cilium

STARD1 stimulates cholesterol transfer to mitochondrial CYP11A1 for conversion to pregnenolone. A cholesterol-binding START domain is guided by an N-terminal domain in a cell selective manner. Fetal and adult Leydig cells (FLC, ALC) show distinct Stard1 regulation. sm- FISH microscopy, which resolves individual molecules of Stard1 mRNA, shows uniformly high basal expression in each FLC. In ALC, in vivo, and cultured MA-10 cells, basal Stard1 expression is minimal. PKA activates loci asynchronously, with delayed splicing/export of 3.5 kb mRNA to mitochondria. After 60 min, ALC transition to an integrated mRNA delivery to mitochondria that is seen in FLC. Sertoli cells cooperate in Stard1 stimulation in FLC by delivering DHH to the primary cilium. There PTCH, SMO and cholesterol cooperate to release GLI3 to activate the Stard1 locus, probably by directing histone changes. ALC lack cilia. PKA then primes locus activation. FLC and ALC share similar SIK/CRTC/CREB regulation characterized for adrenal cells.

Physical activity, ethnicity, and quality of life among breast cancer survivors and population-based controls: the long-term quality of life follow-up study

PURPOSE

To explore the relationship between physical activity (PA) and quality of life (QOL) among Hispanic and non-Hispanic white breast cancer (BC) cases and population-based controls from the New Mexico 'Long-Term Quality of Life Study'.

METHODS

Self-reported PA (low, moderate, vigorous MET hours/week) at baseline and follow-up interviews (12-15 years) were available for 391 cases and controls and modeled using multiple linear regressions with SF-36 mean composite scores for physical and mental health. The change in PA from baseline to follow-up and interactions with ethnicity were also examined. Models were adjusted for age at diagnosis/baseline interview, education, comorbidities, body mass index, and change in PA.

RESULTS

PA intensities at each timepoint did not differ by case/control status; however, the change in vigorous PA was lower among cases (p = 0.03). At follow-up, low intensity PA increased mental health QOL scores among cases; however, the interaction between low intensity PA and ethnicity was statistically significant among controls indicating decreased mental health among Hispanics (p = 0.02). Change in moderate PA was associated with increased physical and mental health among cases (physical: β = 0.186, p = 0.008; mental: β = 0.225, p = 0.001) and controls (physical: β = 0.220, p < 0.0001; mental: β = 0.193, p = 0.002), when controlling for confounders.

CONCLUSION

Our results demonstrate that all levels of PA are important for mental health among BC cases, while activities of higher intensity are important for physical health among women overall. The statistical interaction observed between ethnicity and low intensity PA among controls for mental health warrants further research to provide a meaningful interpretation.

Single-cell analysis of the developing human testis reveals somatic niche cell specification and fetal germline stem cell establishment

Human testis development in prenatal life involves complex changes in germline and somatic cell identity. To better understand, we profiled and analyzed ∼32,500 single-cell transcriptomes of testicular cells from embryonic, fetal, and infant stages. Our data show that at 6-7 weeks postfertilization, as the testicular cords are established, the Sertoli and interstitial cells originate from a common heterogeneous progenitor pool, which then resolves into fetal Sertoli cells (expressing tube-forming genes) or interstitial cells (including Leydig-lineage cells expressing steroidogenesis genes). Almost 10 weeks later, beginning at 14-16 weeks postfertilization, the male primordial germ cells exit mitosis, downregulate pluripotent transcription factors, and transition into cells that strongly resemble the state 0 spermatogonia originally defined in the infant and adult testes. Therefore, we called these fetal spermatogonia "state f0." Overall, we reveal multiple insights into the coordinated and temporal development of the embryonic, fetal, and postnatal male germline together with the somatic niche.

The Therapeutic Potential of Amniotic Fluid-Derived Stem Cells on Busulfan-Induced Azoospermia in Adult Rats

BACKGROUND

Busulfan is an alkylating chemotherapeutic agent that is routinely prescribed for leukemic patients to induce myelo-ablation. However, it also results in azoospermia and infertility in cancer survivors. This research was constructed to explore the possible therapeutic role of amniotic fluid-derived stem cells (AFSCs) in improving busulfan-induced azoospermia in adult rats.

METHODS

Forty two adult male albino rats were randomized into: (1) control group, (2) azoospermia group, (3) spontaneous recovery group, and (4) AFSCs-treated group, in which AFSCs were transplanted through their injection into the testicular efferent ducts. The assessment included a histo-pathological examination of the seminiferous tubules by the light and transmission electron microscopes. Additionally, the confocal laser scanning microscope was used for confirmation of homing of the implanted cells. Moreover, we conducted an immuno-fluorescence study for detection of the proliferating cell nuclear antigen (PCNA) in the spermatogenic cells, epididymal sperm count, and a histo-morphometric study.

RESULTS

AFSCs successfully homed over the basement membrane of the injured seminiferous tubules. They greatly attenuated busulfan-induced degenerative and oxidative changes. They also caused a re-expression of PCNA in the germ cells, leading to resumption of spermatogenesis and re-appearance of spermatozoa.

CONCLUSION

AFSCs could be a promising treatment modality for male infertility induced by chemotherapy, as they possess prominent regenerative, anti-apoptotic, and anti-inflammatory potentials.

Development of Testis Cords and the Formation of Efferent Ducts in Xenopus laevis: Differences and Similarities with Other Vertebrates

The knowledge of testis development in amphibians relative to amniotes remains limited. Here, we used Xenopus laevis to investigate the process of testis cord development. Morphological observations revealed the presence of segmental gonomeres consisting of medullary knots in male gonads at stages 52-53, with no distinct gonomeres in female gonads. Further observations showed that cell proliferation occurs at specific sites along the anterior-posterior axis of the future testis at stage 50, which contributes to the formation of medullary knots. At stage 53, adjacent gonomeres become close to each other, resulting in fusion; then (pre-)Sertoli cells aggregate and form primitive testis cords, which ultimately become testis cords when germ cells are present inside. The process of testis cord formation in X. laevis appears to be more complex than in amniotes. Strikingly, steroidogenic cells appear earlier than (pre-)Sertoli cells in differentiating testes of X. laevis, which differs from earlier differentiation of (pre-)Sertoli cells in amniotes. Importantly, we found that the mesonephros is connected to the testis gonomere at a specific site at early larval stages and that these connections become efferent ducts after metamorphosis, which challenges the previous concept that the mesonephric side and the gonadal side initially develop in isolation and then connect to each other in amphibians and amniotes.

An exploration of the role of Sertoli cells on fetal testis development using cell ablation strategy

Sertoli cells (SCs) are presumed to be the center of testis differentiation because they provide both structural support and biological regulation for spermatogenesis. Previous studies suggest that SCs control germ cell (GC) count and Leydig cell (LC) development in mouse testes. However, the regulatory role of SCs on peritubular myoid (PTM) cell fate in fetal testis has not been clearly reported. Here, we employed Amh-Cre; diphtheria toxin fragment A (DTA) mouse model to selectively ablate SCs from embryonic day (E) 14.5. Results found that SC ablation in the fetal stage caused the disruption of testis cords and the massive loss of GCs. Furthermore, the number of α-smooth muscle actin-labeled PTM cells was gradually decreased from E14.5 and almost lost at E18.5 in SC ablation testis. Interestingly, some Ki67 and 3β-HSD double-positive fetal LCs could be observed in Amh-Cre; DTA testes at E16.5 and E18.5. Consistent with this phenomenon, the messenger RNA levels of Hsd3b1, Cyp11a1, Lhr, Star and the protein levels of 3β-HSD and P450Scc were significantly elevated by SC ablation. SC ablation appears to induce ectopic proliferation of fetal LCs although the total LC number appeared reduced. Together, these findings bring us a better understanding of SCs' central role in fetal testis development.

Evidence that downregulation of Wilms' tumor 1 (WT1) is involved in cortical stromal cell differentiation into theca cells in adult bovine ovaries

Bovine theca cells are thought to differentiate from cortical stromal cells, and ovary-derived Wilms' tumor 1⁺ (WT1⁺ ) cells are the primary source of mouse theca cells. However, it is not known whether the differentiation of cortical stromal cells is regulated by WT1. Here, we identified WT1 in the cortical stroma and theca layer of the bovine ovary and analyzed the theca cell functional markers in cortical stromal cells and theca cells; in addition, we determined the effects of this gene on the secretion of androstenedione and progesterone by cortical stromal cells and the responsiveness of cortical stromal cells to luteinizing hormone (LH) in vitro. We used quantitative reverse-transcription polymerase chain reaction (RT-qPCR), western blot analysis, and immunohistochemistry to discover that the cortical stroma had higher WT1 expression than the theca layer. We used RT-qPCR and ELISA analyses to determine that the cortical stromal cells had lower levels of androstenedione and progesterone secretion and LHR messenger RNA expression than the levels of the theca cells. In cultured bovine cortical stromal cells, we found that WT1 downregulation increased androstenedione and progesterone secretion but had no effect on the LH responsiveness. Notably, the increase in androstenedione and progesterone secretion was associated with an increase in 3-β-hydroxysteroid dehydrogenase expression. In conclusion, the results suggest that WT1 is involved in the differentiation of cortical stromal cells into cells with characteristics similar to theca cells of antral follicles in adult bovine ovaries.

Effect of gestational exposure to perfluorononanoic acid on neonatal mice testes

Perfluoroalkyl acids (PFAAs) are widely used in commercial products and are found in many goods of daily use. Perfluorononanoic acid (PFNA) is one of the PFAAs that possesses endocrine disrupting properties and we have recently shown that PFNA affects testicular functions in Parkes mice. Exposure to environmental endocrine disruptors during fetal life is believed to affect gonadal development and they might produce reproductive abnormalities in males. Therefore, the present study examined the effect of gestational exposure to PFNA on the testes of neonatal mice offspring. Pregnant Parkes mice were orally administered PFNA (2 and 5 mg/kg body weight) or distilled water from gestational day 12 until parturition. Male pups were killed on postnatal day 3. PFNA treatment decreased testosterone biosynthesis by inhibiting expression of steroidogenic acute regulatory protein, cytochrome P450scc, and 3β- and 17β-hydroxysteroid dehydrogenase; proliferation of testicular cells was also affected in treated mice. Furthermore, a marked decrease in expression of Wilms tumor 1, steroidogenic factor 1 and insulin-like factor 3 was noted in neonatal mice testes, indicating that the PFNA treatment may affect the development of the testis. Moreover, observation of the dose-related expression of anti-müllerian hormone and c-Kit in neonatal mice testes is also suggestive of an interference with gonadal development by PFNA exposure. In conclusion, the results suggest that the gestational exposure to PFNA decreased testosterone biosynthesis and altered the expression of critical factors involved in the development of the testis, thereby advocating a potential risk of PFNA to male reproductive health.

Influence of Wilms' tumor suppressor gene WT1 on bovine Sertoli cells polarity and tight junctions via non-canonical WNT signaling pathway

Sertoli cells (SCs) are polarized epithelial cells and provide a microenvironment for the development of germ cells (GCs). The Wilms' tumor suppressor gene WT1 which support spermatogenesis is expressed explicitly in SCs. This study investigated the effect of WT1 on the polarity and blood-testis barrier (BTB) formation of bovine SCs in order to provide theoretical and practical bases for the spermatogenic process in mammals. In this study, newborn calf SCs were used as research material, and the RNAi technique was used to knockdown the endogenous WT1. The results show that WT1 knockdown did not affect the proliferation ability of SCs, but down-regulated the expression of polarity-associated proteins (Par3, Par6b, and E-cadherin), junction-associated protein (occludin) and inhibits transcription of downstream genes (WNT4, JNK, αPKC, and CDC42) in non-canonical WNT signaling pathway. WT1 also altered ZO-1 and occludin protein distribution. Overexpression of WNT1 did not affect the expression of Par6b, E-cadherin, and occludin, whereas the non-canonical WNT signaling pathway inhibitors wnt-c59, CCG-1423, and GO-6983 down-regulated the expression of Par6b, E-cadherin, and occludin respectively. This study indicates that WT1 mediates the regulation of several proteins involved in bovine SCs polarity maintenance and intercellular tight junctions (TJ) by non-canonical WNT signaling pathway.

VCAM1 Is Induced in Ovarian Theca and Stromal Cells in a Mouse Model of Androgen Excess

Ovarian theca androgen production is regulated by the pituitary LH and intrafollicular factors. Enhanced androgen biosynthesis by theca cells contributes to polycystic ovary syndrome (PCOS) in women, but the ovarian consequences of elevated androgens are not completely understood. Our study documents the molecular events that are altered in the theca and stromal cells of mice exposed to high androgen levels, using the nonaromatizable androgen DHT. Changes in ovarian morphology and function were observed not only in follicles, but also in the stromal compartment. Genome-wide microarray analyses revealed marked changes in the ovarian transcriptome of DHT-treated females within 1 week. Particularly striking was the increased expression of vascular cell adhesion molecule 1 (Vcam1) specifically in the NR2F2/COUPTF-II lineage theca cells, not granulosa cells, of growing follicles and throughout the stroma of the androgen-treated mice. This response was mediated by androgen receptors (ARs) present in theca and stromal cells. Human theca-derived cultures expressed both ARs and NR2F2 that were nuclear. VCAM1 mRNA and protein were higher in PCOS-derived theca cells compared with control theca and reduced markedly by the AR antagonist flutamide. In the DHT-treated mice, VCAM1 was transiently induced by equine chorionic gonadotropin, when androgen and estrogen biosynthesis peak in preovulatory follicles, and was potently suppressed by a superovulatory dose of human chorionic gonadotropin. High levels of VCAM1 in the theca and interstitial cells of DHT-treated mice and in adult Leydig cells indicate that there may be novel functions for VCAM1 in reproductive tissues, including the gonads.

Dynein 1 supports spermatid transport and spermiation during spermatogenesis in the rat testis

In the mammalian testis, spermatogenesis is dependent on the microtubule (MT)-specific motor proteins, such as dynein 1, that serve as the engine to support germ cell and organelle transport across the seminiferous epithelium at different stages of the epithelial cycle. Yet the underlying molecular mechanism(s) that support this series of cellular events remain unknown. Herein, we used RNAi to knockdown cytoplasmic dynein 1 heavy chain (Dync1h1) and an inhibitor ciliobrevin D to inactivate dynein in Sertoli cells in vitro and the testis in vivo, thereby probing the role of dynein 1 in spermatogenesis. Both treatments were shown to extensively induce disruption of MT organization across Sertoli cells in vitro and the testis in vivo. These changes also perturbed the transport of spermatids and other organelles (such as phagosomes) across the epithelium. These changes thus led to disruption of spermatogenesis. Interestingly, the knockdown of dynein 1 or its inactivation by ciliobrevin D also perturbed gross disruption of F-actin across the Sertoli cells in vitro and the seminiferous epithelium in vivo, illustrating there are cross talks between the two cytoskeletons in the testis. In summary, these findings confirm the role of cytoplasmic dynein 1 to support the transport of spermatids and organelles across the seminiferous epithelium during the epithelial cycle of spermatogenesis.

Mesothelial to mesenchyme transition as a major developmental and pathological player in trunk organs and their cavities

The internal organs embedded in the cavities are lined by an epithelial monolayer termed the mesothelium. The mesothelium is increasingly implicated in driving various internal organ pathologies, as many of the normal embryonic developmental pathways acting in mesothelial cells, such as those regulating epithelial-to-mesenchymal transition, also drive disease progression in adult life. Here, we summarize observations from different animal models and organ systems that collectively point toward a central role of epithelial-to-mesenchymal transition in driving tissue fibrosis, acute scarring, and cancer metastasis. Thus, drugs targeting pathways of mesothelium’s transition may have broad therapeutic benefits in patients suffering from these diseases.

Tim Koopmans and Yuval Rinkevich review recent findings linking the mesothelium’s embryonic programs that drive epithelial-to-mesenchyme transition with adult pathologies, such as fibrosis, acute scarring, and cancer metastasis. They highlight new avenues for drug development that would target pathways of the mesothelium’s mesenchymal transition.

Actin nucleator Spire 1 is a regulator of ectoplasmic specialization in the testis

Germ cell differentiation during the epithelial cycle of spermatogenesis is accompanied by extensive remodeling at the Sertoli cell-cell and Sertoli cell-spermatid interface to accommodate the transport of preleptotene spermatocytes and developing spermatids across the blood-testis barrier (BTB) and the adluminal compartment of the seminiferous epithelium, respectively. The unique cell junction in the testis is the actin-rich ectoplasmic specialization (ES) designated basal ES at the Sertoli cell-cell interface, and the apical ES at the Sertoli-spermatid interface. Since ES dynamics (i.e., disassembly, reassembly and stabilization) are supported by actin microfilaments, which rapidly converts between their bundled and unbundled/branched configuration to confer plasticity to the ES, it is logical to speculate that actin nucleation proteins play a crucial role to ES dynamics. Herein, we reported findings that Spire 1, an actin nucleator known to polymerize actins into long stretches of linear microfilaments in cells, is an important regulator of ES dynamics. Its knockdown by RNAi in Sertoli cells cultured in vitro was found to impede the Sertoli cell tight junction (TJ)-permeability barrier through changes in the organization of F-actin across Sertoli cell cytosol. Unexpectedly, Spire 1 knockdown also perturbed microtubule (MT) organization in Sertoli cells cultured in vitro. Biochemical studies using cultured Sertoli cells and specific F-actin vs. MT polymerization assays supported the notion that a transient loss of Spire 1 by RNAi disrupted Sertoli cell actin and MT polymerization and bundling activities. These findings in vitro were reproduced in studies in vivo by RNAi using Spire 1-specific siRNA duplexes to transfect testes with Polyplus in vivo-jetPEI as a transfection medium with high transfection efficiency. Spire 1 knockdown in the testis led to gross disruption of F-actin and MT organization across the seminiferous epithelium, thereby impeding the transport of spermatids and phagosomes across the epithelium and perturbing spermatogenesis. In summary, Spire 1 is an ES regulator to support germ cell development during spermatogenesis.

WT1 Is Necessary for the Proliferation and Migration of Cells of Renin Lineage Following Kidney Podocyte Depletion

Wilms' tumor suppressor 1 (WT1) plays an important role in cell proliferation and mesenchymal-epithelial balance in normal development and disease. Here, we show that following podocyte depletion in three experimental models, and in patients with focal segmental glomerulosclerosis (FSGS) and membranous nephropathy, WT1 increased significantly in cells of renin lineage (CoRL). In an animal model of FSGS in RenWt1^fl/fl reporter mice with inducible deletion of WT1 in CoRL, CoRL proliferation and migration to the glomerulus was reduced, and glomerular disease was worse compared with wild-type mice. To become podocytes, CoRL undergo mesenchymal-to-epithelial transformation (MET), typified by reduced staining for mesenchymal markers (MYH11, SM22, αSMA) and de novo expression of epithelial markers (E-cadherin and cytokeratin18). Evidence for changes in MET markers was barely detected in RenWt1^fl/fl mice. Our results show that following podocyte depletion, WT1 plays essential roles in CoRL proliferation and migration toward an adult podocyte fate.

Ex vivo cultures combined with vivo-morpholino induced gene knockdown provide a system to assess the role of WT1 and GATA4 during gonad differentiation

Gonad morphogenesis relies on the correct spatiotemporal expression of a number of genes that together fulfill the differentiation of the bipotential gonad into testes or ovaries. As such, the transcription factors WT1 and GATA4 are pivotal for proper gonadal development. Here we address the contributions of GATA4 and WT1 to the sex differentiation phase in testes and ovaries. We applied an ex vivo technique for cultivating gonads in hanging droplets of media that were supplemented with vivo-morpholinos to knockdown WT1 and GATA4 either alone or in combination at the same developmental stage. We show that WT1 is equally important for both, the initial establishment and the maintenance of the sex-specific gene expression signature in testes and ovaries. We further identified Foxl2 as a novel putative downstream target gene of WT1. Moreover, knockdown of WT1 reduced mRNA levels of several molecular components of the hedgehog signaling pathway in XY gonads, whereas Gata4 vivo-morpholino treatment increased transcripts of Dhh and Ptch1 in embryonic testes. The data suggest that for its proper function, WT1 relies on the correct expression of the GATA4 protein. Furthermore, GATA4 down-regulates several ovarian promoting genes in testes, such as Ctnnb1, Fst, and Bmp2, suggesting that this repression is required for maintaining the male phenotype. In conclusion, this study provides novel insights into the role of WT1 and GATA4 during the sex differentiation phase and represents an approach that can be applied to assess other proteins with as yet unknown functions during gonadal development.