E4 Transcription Factor 1 (E4F1) Regulates Sertoli Cell Proliferation and Fertility in Mice

In the mammalian testes, Sertoli cells are the only somatic cells in the seminiferous tubules that provide structural, nutritional and regulatory support for developing spermatogenic cells. Sertoli cells only proliferate during the fetal and neonatal periods and enter a quiescent state after puberty. Functional evidences suggest that the size of Sertoli cell population determines sperm production and fertility. However, factors that direct Sertoli cell proliferation and maturation are not fully understood. Transcription factor E4F1 is a multifunctional protein that serves essential roles in cell fate decisions and because it interacts with pRB, a master regulator of Sertoli cell function, we hypothesized that E4F1 may have a functional role in Sertoli cells. E4f1 mRNA was present in murine testis and immunohistochemical staining confirmed that E4F1 was enriched in mature Sertoli cells. We generated a conditional knockout mouse model using Amh-cre and E4f1flox/flox lines to study E4F1 fucntion in Sertoli cells and the results showed that E4f1 deletion caused a significant reduction in testis size and fertility. Further analyses revealed that meiosis progression and spermiogenesis were normal, however, Sertoli cell proliferation was impaired and germ cell apoptosis was elevated in the testis of E4f1 conditional knockout mice. On the basis of these findings, we concluded that E4F1 was expressed in murine Sertoli cells and served important functions in regulating Sertoli cell proliferation and fertility.

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Testicular Somatic Cells, not Gonocytes, Are the Major Source of Functional Activin A during Testis Morphogenesis

Endocrinology ◽

10.1210/en.2011-1288 ◽

2011 ◽

Vol 152 (11) ◽

pp. 4358-4367 ◽

Cited By ~ 8

Author(s):

Denise R. Archambeault ◽

Jessica Tomaszewski ◽

Andrew J. Childs ◽

Richard A. Anderson ◽

Humphrey Hung-Chang Yao

Keyword(s):

Cell Proliferation ◽

Sertoli Cell ◽

Somatic Cells ◽

Activin A ◽

Protein Product ◽

Conditional Knockout ◽

Seminiferous Tubules ◽

Testis Size ◽

Testis Development ◽

Testis Cord

Proper development of the seminiferous tubules (or testis cords in embryos) is critical for male fertility. Sertoli cells, somatic components of the seminiferous tubules, serve as nurse cells to the male germline, and thus their numbers decide the quantity of sperm output in adulthood. We previously identified activin A, the protein product of the activin βA (Inhba) gene, as a key regulator of murine Sertoli cell proliferation and testis cord expansion during embryogenesis. Although our genetic studies implicated fetal Leydig cells as the primary producers of testicular activin A, gonocytes are another potential source. To investigate the relative contribution of gonocyte-derived activin A to testis morphogenesis, we compared testis development in the Inhba global knockout mouse, which lacks activin A production in all cells (including the gonocytes), and a steroidogenic factor 1 (Sf1)-specific conditional knockout model in which activin A expression in testicular somatic cells is disrupted but gonocyte expression of activin A remains intact. Surprisingly, testis development was comparable in these two models of activin A insufficiency, with similar reductions in Sertoli cell proliferation and minor differences in testis histology. Thus, our findings suggest activin A from male gonocytes is insufficient to promote Sertoli cell proliferation and testis cord expansion in the absence of somatic cell-derived activin A. Evaluation of adult male mice with fetal disruption of activin A revealed reduced testis size, lowered sperm production, altered testicular histology, and elevated plasma FSH levels, defects reminiscent of human cases of androgen-sufficient idiopathic oligozoospermia.

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UXT in Sertoli cells is required for blood–testis barrier integrity†

Biology of Reproduction ◽

10.1093/biolre/ioaa121 ◽

2020 ◽

Vol 103 (4) ◽

pp. 880-891

Author(s):

Phillip A Thomas ◽

Eric D Schafler ◽

Sophie E Ruff ◽

Maud Voisin ◽

Susan Ha ◽

...

Keyword(s):

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Structural Integrity ◽

Cell Function ◽

Somatic Tissue ◽

Seminiferous Tubules ◽

Testis Size ◽

Conditional Deletion ◽

Blood Testis Barrier

Abstract Spermatogenesis is a complex process that establishes male fertility and involves proper communication between the germline (spermatozoa) and the somatic tissue (Sertoli cells). Many factors that are important for spermatozoa production are also required for Sertoli cell function. Recently, we showed that the transcriptional cofactor ubiquitously expressed transcript (UXT) encodes a protein that is essential in germ cells for spermatogenesis and fertility. However, the role of UXT within Sertoli cells and how it affects Sertoli cell function was still unclear. Here we describe a novel role for UXT in the Sertoli cell’s ability to support spermatogenesis. We find that the conditional deletion of Uxt in Sertoli cells results in smaller testis size and weight, which coincided with a loss of germ cells in a subset of seminiferous tubules. In addition, the deletion of Uxt has no impact on Sertoli cell abundance or maturity, as they express markers of mature Sertoli cells. Gene expression analysis reveals that the deletion of Uxt in Sertoli cells reduces the transcription of genes involved in the tight junctions of the blood–testis barrier (BTB). Furthermore, tracer experiments and electron microscopy reveal that the BTB is permeable in UXT KO animals. These findings broaden our understanding of UXT’s role in Sertoli cells and its contribution to the structural integrity of the BTB.

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Developmental stage- and spermatogenic cycle-specific expression of transcription factor GATA-1 in mouse Sertoli cells

Development ◽

10.1242/dev.120.7.1759 ◽

1994 ◽

Vol 120 (7) ◽

pp. 1759-1766 ◽

Cited By ~ 6

Author(s):

K. Yomogida ◽

H. Ohtani ◽

H. Harigae ◽

E. Ito ◽

Y. Nishimune ◽

...

Keyword(s):

Transcription Factor ◽

Developmental Stage ◽

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Transcriptional Activation ◽

Germ Line ◽

Mouse Testis ◽

Seminiferous Tubules ◽

Specific Expression

GATA-1 is an essential factor for the transcriptional activation of erythroid-specific genes, and is also abundantly expressed in a discrete subset of cells bordering the seminiferous epithelium in tubules of the murine testis. In examining normal and germ-line defective mutant mice, we show here that GATA-1 is expressed only in the Sertoli cell lineage in mouse testis. GATA-1 expression in Sertoli cells is induced concomitantly with the first wave of spermatogenesis, and GATA-1-positive cells are uniformly distributed among all tubules during prepubertal testis development. However, the number of GATA-1-positive cells declines thereafter and were found only in the peripheral zone of seminiferous tubules in stages VII, VIII and IX of spermatogenesis in the adult mouse testis. In contrast, virtually every Sertoli cell in mutant W/Wv, jsd/jsd or cryptorchid mice (all of which lack significant numbers of germ cells) expresses GATA-1, thus showing that the expression of this transcription factor is negatively controlled by the maturing germ cells. These observations suggest that transcription factor GATA-1 is a developmental stage- and spermatogenic cycle-specific regulator of gene expression in Sertoli cells.

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The Molecular Mechanism of Sex Hormones on Sertoli Cell Development and Proliferation

Frontiers in Endocrinology ◽

10.3389/fendo.2021.648141 ◽

2021 ◽

Vol 12 ◽

Author(s):

Wasim Shah ◽

Ranjha Khan ◽

Basit Shah ◽

Asad Khan ◽

Sobia Dil ◽

...

Keyword(s):

Cell Proliferation ◽

Sertoli Cell ◽

Sex Hormones ◽

Sertoli Cells ◽

Production Capacity ◽

Cell Development ◽

Seminiferous Tubules ◽

Recent Advancement ◽

Specific Number

Sustaining and maintaining the intricate process of spermatogenesis is liable upon hormones and growth factors acting through endocrine and paracrine pathways. The Sertoli cells (SCs) are the major somatic cells present in the seminiferous tubules and are considered to be the main regulators of spermatogenesis. As each Sertoli cell supports a specific number of germ cells, thus, the final number of Sertoli cells determines the sperm production capacity. Similarly, sex hormones are also major regulators of spermatogenesis and they can determine the proliferation of Sertoli cells. In the present review, we have critically and comprehensively discussed the role of sex hormones and some other factors that are involved in Sertoli cell proliferation, differentiation and maturation. Furthermore, we have also presented a model of Sertoli cell development based upon the recent advancement in the field of reproduction. Hence, our review article provides a general overview regarding the sex hormonal pathways governing Sertoli cell proliferation and development.

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miR-499 promotes immature porcine Sertoli cell growth through the PI3K/AKT pathway by targeting the PTEN gene

Reproduction ◽

10.1530/rep-19-0303 ◽

2020 ◽

Vol 159 (2) ◽

pp. 145-157 ◽

Cited By ~ 3

Author(s):

Hu Gao ◽

Bin Chen ◽

Hui Luo ◽

Bo Weng ◽

Xiangwei Tang ◽

...

Keyword(s):

Cell Proliferation ◽

Cell Growth ◽

Signaling Pathway ◽

Sertoli Cell ◽

Sertoli Cells ◽

Akt Signaling ◽

Akt Pathway ◽

Pten Gene ◽

Seminiferous Tubules ◽

Akt Signaling Pathway

Sertoli cells are indispensable for normal spermatogenesis, and increasing evidence has shown that miRNAs participate in the regulation of Sertoli cell growth. However, the functions and regulatory mechanisms of miRNAs in Sertoli cells of domestic animals have not been fully investigated. In the present study, we mainly investigated the regulatory roles of miR-499 in immature porcine Sertoli cells. The results showed that miR-499 was mainly located in the basement section of seminiferous tubules of prepubertal porcine testicular tissue. Overexpression of miR-499 promoted cell proliferation and inhibited apoptosis, whereas miR-499 inhibition resulted in the opposite effect. The PTEN gene was directly targeted by miR-499, and the expression of mRNA and protein was also negatively regulated by miR-499 in immature porcine Sertoli cells. siRNA-induced PTEN knockdown resulted in a similar effect as an overexpression of miR-499 and abolished the effects of miR-499 inhibition on immature porcine Sertoli cells. Moreover, both miR-499 overexpression and the PTEN knockdown activated the PI3K/AKT signaling pathway, whereas inhibition of the PI3K/AKT signaling pathway caused immature porcine Sertoli cell apoptosis and inhibited cell proliferation. Overall, miR-499 promotes proliferation and inhibits apoptosis in immature porcine Sertoli cells through the PI3K/AKT pathway by targeting the PTEN gene. This study provides novel insights into the effects of miR-499 in spermatogenesis through the regulation of immature Sertoli cell proliferation and apoptosis.

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BRG1 Is Dispensable for Sertoli Cell Development and Functions in Mice

International Journal of Molecular Sciences ◽

10.3390/ijms21124358 ◽

2020 ◽

Vol 21 (12) ◽

pp. 4358

Author(s):

Shuai Wang ◽

Pengxiang Wang ◽

Dongli Liang ◽

Yuan Wang

Keyword(s):

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Cell Development ◽

Conditional Knockout ◽

Mouse Strains ◽

Seminiferous Tubules ◽

Supporting Cells ◽

Knockout Mouse Model ◽

Conditional Knockout Mouse

Sertoli cells are somatic supporting cells in spermatogenic niche and play critical roles in germ cell development, but it is yet to be understood how epigenetic modifiers regulate Sertoli cell development and contribution to spermatogenesis. BRG1 (Brahma related gene 1) is a catalytic subunit of the mammalian SWI/SNF chromatin remodeling complex and participates in transcriptional regulation. The present study aimed to define the functions of BRG1 in mouse Sertoli cells during mouse spermatogenesis. We found that BRG1 protein was localized in the nuclei of both Sertoli cells and germ cells in seminiferous tubules. We further examined the requirement of BRG1 in Sertoli cell development using a Brg1 conditional knockout mouse model and two Amh-Cre mouse strains to specifically delete Brg1 gene from Sertoli cells. We found that the Amh-Cre mice from Jackson Laboratory had inefficient recombinase activities in Sertoli cells, while the other Amh-Cre strain from the European Mouse Mutant Archive achieved complete Brg1 deletion in Sertoli cells. Nevertheless, the conditional knockout of Brg1 from Sertoli cells by neither of Amh-Cre strains led to any detectable abnormalities in the development of either Sertoli cells or germ cells, suggesting that BRG1-SWI/SNF complex is dispensable to the functions of Sertoli cells in spermatogenesis.

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300 IMMUNO-EXPRESSION OF POTENTIAL FACTORS REGULATING SERTOLI CELL PROLIFERATION IN THE PREPUBERTAL BOAR

Reproduction Fertility and Development ◽

10.1071/rdv18n2ab300 ◽

2006 ◽

Vol 18 (2) ◽

pp. 257

Author(s):

J. Baldrighi ◽

W. Averhart ◽

T. Phillips ◽

K. Carnes ◽

R. Hess ◽

...

Keyword(s):

Cell Cycle ◽

Cell Proliferation ◽

Sertoli Cell ◽

Sertoli Cells ◽

Testis Size ◽

Regulatory Factors ◽

Time Points ◽

Stage Of Development ◽

Potential Factors ◽

P27 Kip1

Today's pork production is very dependent on reproductive efficiency. Any improvements in the production capability (e.g., number of sperm produced) of the animals involved would be invaluable. Many researchers have examined methods to improve oocyte production, but have not focused on the concentration of sperm produced from a single boar used for artificial insemination (AI). The benefit of using AI is that a greater number of females can be bred to a single boar; thus the total amount of sperm per ejaculation is the main factor in the efficiency of AI. An increase in the number of Sertoli cells leads to an increase in testis size and the number of sperm produced because there are a finite number of germ cells that can be supported by the Sertoli cell during spermatogenesis. Therefore, by examining the factors that control the growth and differentiation of Sertoli cells, the amount of sperm per ejaculation in an individual boar can be increased. The purpose of this research is to begin a systematic analysis of cell cycle regulators expressed in the Sertoli cell during testicular development in the pig. By using pigs of different ages, we will establish a baseline of what regulatory factors are present at different time points in the developing Sertoli cell. Identification of certain factors could lead to an increase in sperm production by enabling the growth of Sertoli cells or inhibition of the natural reduction of these cells. Immunohistochemistry (IHC) analysis was performed on testis tissues from different males (n = 2) at various ages (3, 7, 14, 25, and 50 days) prior to puberty. Tissues were fixed in modified Davidson's fixative, embedded in paraffin, and sectioned; slides were processed for IHC. After antigen retrieval, endogenous hydrogen peroxidase was blocked with 0.6% H2O2 and sections were incubated overnight at 4°C with the appropriate antibody. The following antibodies were used to examine the factors controlling Sertoli cell proliferation: GATA-4 (transcription factor specific for developing and adult pig Sertoli cells), Ki67 (a nuclear protein present in all phases of the cell cycle except G0), cyclin-dependent kinase inhibitor p27 (Kip1), and steroid receptors AR (androgen receptor) and LH2 (estrogen receptor). The slides were then incubated with an appropriate secondary antibody, visualized with DAB chromagen, and counterstained with Mayer's hematoxylin. Immunostaining using p27 (Kip1) revealed no positive staining in any of the days tested, as there is cell division during all of these time points. Protein expression for Ki67 stained mildly after Day 25, suggesting that Sertoli cells became more active at this stage of development. The AR weakly stained and GATA-1 stained intensely at all time points. The data for LH2 were inconclusive and the procedure needs to be performed again. These experiments only give a glimpse of the regulatory factors involved in Sertoli cell proliferation in the developing boar testis. Further studies are being planned to explore other potential factors involved.

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Role of the Basic Helix-Loop-Helix Transcription Factor, Scleraxis, in the Regulation of Sertoli Cell Function and Differentiation

Molecular Endocrinology ◽

10.1210/me.2004-0473 ◽

2005 ◽

Vol 19 (8) ◽

pp. 2164-2174 ◽

Cited By ~ 24

Author(s):

Tera Muir ◽

Ingrid Sadler-Riggleman ◽

Michael K. Skinner

Keyword(s):

Transcription Factor ◽

Transcription Factors ◽

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Antisense Oligonucleotide ◽

Cell Function ◽

Gene Products ◽

Basic Helix Loop Helix ◽

Helix Loop Helix

Abstract Sertoli cells are a postmitotic terminally differentiated cell population in the adult testis that form the seminiferous tubules and provide the microenvironment and structural support for developing germ cells. The transcription factors that regulate Sertoli cell differentiation remain to be elucidated. The basic helix-loop-helix transcription factors are involved in the differentiation of a variety of cell lineages during development and are expressed in pubertal Sertoli cells. A yeast-two-hybrid procedure was used to screen a Sertoli cell library from 20-d-old pubertal rats to identify dimerization partners with the ubiquitous E47 basic helix-loop-helix transcription factor. Scleraxis was identified as one of the interacting partners. Among the cell types of the testis, scleraxis expression was found to be specific to Sertoli cells. Analysis of the expression pattern of scleraxis mRNA in developing Sertoli cells revealed an increase in scleraxis message at the onset of puberty. Sertoli cells respond to FSH to promote expression of differentiated gene products such as transferrin that aid in proper development of the germ cells. Analysis of the hormonal regulation of scleraxis expression revealed a 4-fold increase in scleraxis mRNA in response to the presence of FSH or dibutryl cAMP in cultured Sertoli cells. An antisense oligonucleotide procedure and overexpression analysis were used to determine whether scleraxis regulates the expression of Sertoli cell differentiated gene products. An antisense oligonucleotide to scleraxis down-regulated transferrin promoter activity in Sertoli cells. A transient overexpression of scleraxis in Sertoli cells stimulated transferrin and androgen binding protein promoter activities and the expression of a number of differentiated genes. Observations suggest scleraxis functions in a number of adult tissues and is involved in the regulation and maintenance of Sertoli cell function and differentiation. This is one of the first adult and nontendon/chondrocyte-associated functions described for scleraxis.

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Neonatal administration of FSH increases Sertoli cell numbers and spermatogenesis in gonadotropin-deficient (hpg) mice

Journal of Endocrinology ◽

10.1677/joe.0.1510037 ◽

1996 ◽

Vol 151 (1) ◽

pp. 37-48 ◽

Cited By ~ 60

Author(s):

J Singh ◽

D J Handelsman

Keyword(s):

Cell Proliferation ◽

Germ Cell ◽

Sertoli Cell ◽

Germ Cells ◽

Sertoli Cells ◽

Postnatal Life ◽

Testis Size ◽

Cell Numbers ◽

Natural Time ◽

Neonatal Administration

Abstract We previously demonstrated that androgens alone, in the complete absence of gonadotropins, initiated qualitatively complete spermatogenesis in hypogonadal (hpg) mice. Although germ cell to Sertoli cell ratios were normal in hpg mice with androgen-induced spermatogenesis, testicular size, Sertoli cell and germ cell numbers only reached 40% of those of non-hpg mice, and Sertoli cell numbers were unaffected by androgen treatment started at 21 days of age. We postulated that these observations were due to diminished gonadotropin-dependent Sertoli cell proliferation during perinatal life while the Sertoli cells still exhibited normal carrying capacity for mature germ cells. In order to test this hypothesis, we examined the effects of administering androgens and gonadotropins to hpg mice during the first 2 weeks of postnatal life when Sertoli cells normally continue to proliferate. The study end-points were Sertoli and germ cell numbers in hpg mice following induction of spermatogenesis by 8 weeks treatment with 1 cm subdermal silastic testosterone implants. Newborn pups (postnatal day 0–1) were injected s.c. with recombinant human FSH (rhFSH) (0·5 IU/20 μl) or saline once daily for 14 days, with or without a single dose of testosterone propionate (TP) (100 μg/20 μl arachis oil) or human chorionic gonadotropin (hCG) (1 IU/20 μl). Untreated hpg and phenotypically normal littermates were studied as concurrent controls. At 21 days of age, all treated weanling mice received a 1 cm silastic subdermal testosterone implant and, finally, 8 weeks after testosterone implantation, all mice were killed. As expected, qualitatively complete spermatogenesis was induced in all groups by testosterone despite undetectable circulating FSH levels. Exogenous rhFSH increased testis size by 43% (P<0·002) but a single neonatal dose of either TP or hCG reduced the FSH effect although neither TP nor hCG had any effect alone. In contrast, a single neonatal dose of TP or hCG increased final seminal vesicle size whereas FSH had no effect. FSH and TP treatment significantly increased absolute numbers of testicular spermatids compared with saline treatment, whereas hCG and TP significantly increased testicular sperm when expressed relative to testis size. Stereological evaluation of Sertoli and germ cell numbers demonstrated a rise in the absolute numbers of Sertoli and all germ cell populations induced by neonatal administration of hormones. When expressed per Sertoli cells the numbers of germ cells in the treated mice were between 85 and 90% of non-hpg controls. We conclude that exogenous FSH treatment during the first 2 weeks of postnatal life, coinciding with the natural time of Sertoli cell proliferation, increases Sertoli cell numbers and thereby the ultimate size of the mature testis and its germ cell production. Thus neonatal gonadotropin secretion may be a critical determinant of the sperm-producing capacity of the mature testis. In addition, neonatal exposure to androgens could be important for the imprinting of sex accessory organs in hpg mice, with the long-term effects of altering the sensitivity of the accessory organs to exogenous testosterone later in life. Journal of Endocrinology (1996) 151, 37–48

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DDB1 Regulates Sertoli Cell Proliferation and Testis Cord Remodeling by TGFβ Pathway

Genes ◽

10.3390/genes10120974 ◽

2019 ◽

Vol 10 (12) ◽

pp. 974

Author(s):

Wei Zheng ◽

Jabeen Nazish ◽

Fazal Wahab ◽

Ranjha Khan ◽

Xiaohua Jiang ◽

...

Keyword(s):

Cell Proliferation ◽

Sertoli Cell ◽

Sertoli Cells ◽

Transforming Growth Factor ◽

Seminiferous Tubules ◽

Exact Nature ◽

Genetic Ablation ◽

Testis Cord ◽

Tgfβ Pathway

Testis cords are the embryonic precursors of the seminiferous tubules. Development of testis cords is a key event during embryonic testicular morphogenesis and is regulated by multiple signaling molecules produced by Sertoli cells. However, the exact nature and the cascade of molecular events underlying testis cord development remain to be uncovered. In the current study, we explored the role of DNA damage binding protein 1 (DDB1) in Sertoli cells during mouse testis cord development. The genetic ablation of Ddb1 specifically in Sertoli cells resulted in the compromised Sertoli cell proliferation and disruption of testis cord remodeling in neonatal mice. This testicular dysgenesis persisted through adulthood, resulting in smaller testis and low sperm production. Mechanistically, we observed that the DDB1 degradation can stabilize SET domain-containing lysine methyltransferase 8 (SET8), which subsequently decreases the phosphorylation of SMAD2, an essential intracellular component of transforming growth factor beta (TGFβ) signaling. Taken together, our results suggest an essential role of Ddb1 in Sertoli cell proliferation and normal remodeling of testis cords via TGFβ pathway. To our knowledge, this is the first upstream regulators of TGFβ pathway in Sertoli cells, and therefore it furthers our understanding of testis cord development.

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