Testosterone regulates the autophagic clearance of androgen binding protein in rat Sertoli cells

Role of Testosterone Signaling in Microglia: A Potential Role for Sex-Related Differences in Alzheimer's Disease

Alzheimer's disease (AD) is less prevalent in men than in women, although mechanisms remain unclear. Microglia degrade aggregated amyloid β (Aβ) through the lysosomal system, including autophagy. G protein-coupled receptor family C group 6 member A (GPRC6A), predominantly expressed in mouse microglial MG6 cells, is a primary mediator of testosterone signaling. This study examines testosterone's role in modulating Aβ-induced autophagy in microglia. Testosterone promotes Aβ-induced autophagy leading to Aβ clearance in MG6 cells by suppressing extracellular signal-regulated kinase (ERK) phosphorylation and subsequently inhibiting mammalian target of rapamycin (mTOR) activation, which is abrogated by shRNA knockdown of GPRC6A. In in vivo experiments with male 5xFAD AD model mice, Aβ clearance activity is associated with autophagy in microglia and is reduced by orchiectomy, but restored by testosterone supplementation. ERK phosphorylation in the brains of male AD model mice is upregulated by orchiectomy. Therefore, testosterone is involved in autophagy-mediated Aβ clearance in microglia. Aβ accumulation in human brain samples from patients with AD is significantly lower in men than in women, with less pronounced colocalization of Aβ with p62 aggregates, suggesting enhanced autophagic activity in men. In conclusion, testosterone enhances Aβ-induced autophagy in microglia, possibly contributing to lower susceptibility to AD in men.

Steroid Signaling in Autophagy

Autophagy is a conserved cellular process essential for homeostasis and development that plays a central role in the degradation and recycling of cellular components. Recent studies reveal bidirectional interactions between autophagy and steroid-hormone signaling. Steroids are signaling molecules synthesized from cholesterol that regulate key physiological and developmental processes - including autophagic activity. Conversely, other work demonstrates that autophagy regulates steroid production by controlling the availability of precursor sterol substrate. Insights from Drosophila and mammalian models provide compelling evidence for the conservation of these mechanisms across species. In this review we explore how steroid hormones modulate autophagy in diverse tissues and contexts, such as metabolism and disease, and discuss advances in our understanding of autophagy's regulatory role in steroid hormone production. We examine the implications of these interactions for health and disease and offer perspectives on the potential for harnessing this functionality for addressing cholesterol-related disorders.

Follicle-Stimulating Hormone and Testosterone Play a Role in the Regulation of Sertoli Cell Functions Following Germ Cell Depletion In Vitro

Spermatogenesis is a process of self-renewal of spermatogonial stem cells and their proliferation and differentiation to generate mature sperm. This process involves interactions between testicular somatic (mainly Sertoli cells) and spermatogonial cells at their different stages of development. The functionality of Sertoli cells is regulated by hormones and testicular autocrine/paracrine factors. In this study, we investigated the effects of follicle-stimulating hormone (FSH) and testosterone addition on Sertoli cell cultures that undergo hypotonic shock, with a primary focus on Sertoli cell activity. Cells were enzymatically isolated from testicular seminiferous tubules of 7-day-old mice. These cells were cultured in vitro for 3 days. Thereafter, some cultures were treated with hypotonic shock to remove germ cells. After overnight, fresh media without (control; CT) or with FSH, testosterone (Tes), or FSH+T were added to the hypotonic shock-treated or untreated (CT) cultures for 24 h. The morphology of the cultures and the presence of Sertoli cells and germ cells were examined. The expression of growth factors (CSF-1, LIF, SCF, GDNF) or other specific Sertoli cell factors [transferrin, inhibin b, androgen receptor (AR), androgen binding protein (ABP), FSH receptor (FSHR)] was examined by qPCR. Our immunofluorescence staining showed depletion/major reduction in VASA-positive germ cells in Sertoli cell cultures following hypotonic shock (HYP) treatment compared to untreated cultures (WO). Furthermore, the expression of the examined growth factors and other factors was significantly increased in HYP cultures compared to WO (in the CT). However, the addition of hormones significantly decreased the expression levels of the growth factors in HYP cultures compared to WO cultures under the same treatment. In addition, the expression of all other examined Sertoli cell factors significantly changed following HYP treatment compared to WO and following treatment with FSH and or T. However, the expression levels of some factors remained normal following the treatment of Sertoli cell cultures with one or both hormones (transferrin, Fsh-r, Abp, Ar). Thus, our results demonstrate the crucial role of germ cells in the functionality of Sertoli cells and the possible role of FSH and T in maintaining, at least partially, the normal activity of Sertoli cells following germ cell depletion in vitro by hypotonic shock treatment.

In-utero exposure to real-life environmental chemicals disrupts gene expression within the hypothalamo-pituitary-gonadal axis of prepubertal and adult rams

Environmental chemicals (ECs) have been associated with a broad range of disorders and diseases. Daily exposure to various ECs in the environment, or real-life exposure, has raised significant public health concerns. Utilizing the biosolids-treated pasture (BTP) sheep model, this study demonstrates that in-utero exposure to a real-life EC mixture disrupts hypothalamo-pituitary-gonadal (HPG) axis gene expression and reproductive traits in prepubertal (8-week-old, 8w) and adult (11-month-old) male sheep. Ewes were maintained on either BTP or pastures fertilized with inorganic fertilizer [control (C)] from approximately one month prior to insemination until around parturition. Thereafter, all animals were kept under control conditions. Effects on reproductive parameters including testosterone concentrations and the expression of key genes in the HPG axis were evaluated in eight-week-old and adult male offspring from both C and biosolids-exposed (B) groups. Results showed that, at 8w, relative to C (n = 11), B males (n = 11) had lower body weight, and altered testicular expression of HSD3B1, LHR and HSD17B3, BMP4, ABP, P27kip and CELF1. Principal component analysis (PCA) identified two 8w B subgroups, based on hypothalamic expression of GnRH, ESR1, and AR, and pituitary expression of KISSR. The two subgroups also exhibited different serum testosterone concentrations. The largest biosolids effects were observed in the hypothalamus of adult rams with NKB, ESR1, KISS1, AR, DLK1 and GNRH1 mRNA expression differing between B (n = 10) and C (n = 11) rams. Testicular steroidogenic enzymes CYP11A1 and HSD3B1 mRNA expression also differed between exposure groups. PCA identified two adult B subgroups, with BS1 (n = 6) displaying hypothalamic effects and BS2 (n = 4) both hypothalamic and testicular effects. The subgroups also differed in circulating testosterone concentrations. These findings demonstrate that exposure to a real-life EC mixture may predispose some males to infertility, by disrupting key functional HPG markers before puberty with consequent downstream effects on steroid hormones and spermatogenesis.

Oxidative Stress and Autophagy: Unraveling the Hidden Threat to Boars' Fertility

This review systematically examines the influence of oxidative stress on the reproductive function of male livestock, with a particular focus on the modulation of autophagy. Spermatogenesis, a highly precise biological process, is vulnerable to a range of internal and external factors, among which oxidative stress notably disrupts autophagic processes within the testes. This disruption results in diminished sperm quality, impaired testosterone synthesis, and compromised integrity of the blood-testis barrier. Furthermore, this review elucidates the molecular mechanisms by which oxidative stress-induced autophagy dysfunction impairs spermatogenesis and mitochondrial function, consequently reducing sperm motility. These findings aim to provide a theoretical foundation and serve as a reference for improving reproductive performance and sperm quality in livestock.

Melatonin protects spermatogenic cells against DNA damage and necroptosis induced by atrazine

Atrazine (ATZ), a widely used triazine herbicide, has been shown to disrupt reproductive development in organisms. Melatonin (MLT) is a natural hormone and has been shown to have strong antioxidant properties. Due to its lipophilicity, it can cross biological barriers freely and act on germ cells directly. However, the mechanism through which melatonin affects atrazine-induced damage to male sperm cells remains unclear. This study aimed to investigate the effects of ATZ on spermatocyte development and to elucidate MLT's role in preventing ATZ-induced spermatogenesis failure. Pubertal mice were randomly divided into four groups: blank control group (Con), 5 mg/kg melatonin group (MLT), 170 mg/kg atrazine group (ATZ), and ATZ + MLT group. GC-1 cell culture was employed to access the in vitro effects of MLT and ATZ on spermatogonia. The results indicate that atrazine affected protein and metabolite composition, and reduced sperm viability, sperm motility (VAP, VSL and VCL) and levels of proteins related to spermatogenesis function in the mice testis. Melatonin alleviated the development of cellular DNA damage and necroptosis caused by atrazine both in vivo and in vitro. Moreover, we proposed that it was GC-1 cells developing necroptosis, but not other cell types in the testis. In conclusion, this study suggests that atrazine disrupts the development process, causing DNA damage in spermatozoa during spermatogenesis. Additionally, ATZ-induced necroptosis specifically targets spermatogenic cells. Notably, melatonin alleviates atrazine-induced necroptosis and DNA damage in spermatogenic cells. This study provides new insights into potential therapeutic strategies for atrazine-induced male infertility.

Antibody fragments targeting the extracellular domain of follicular stimulating hormone receptor for contraception in male dogs and cats

The increased LH levels resulting from the absence of negative feedback after castration has been linked to long-term health issues. A need exists for an alternative contraceptive agent that functions without interfering the LH pathways. This study aimed to develop antibody fragments against the follicular-stimulating hormone receptor (anti-FSHr) using phage-display technology and evaluate its effects on Sertoli cell functions. Phage clones against the extracellular domain of dog and cat FSHr selected from an antibody fragment phagemid library were analyzed for binding kinetics by surface plasmon resonance. Sertoli cells were isolated from testes of adult animals (five dogs and five cats). Efficacy test was performed by treating Sertoli cell cultures (SCCs) with anti-FSHr antibody fragments compared with untreated in triplicates. Expressions of androgen binding protein (ABP), inhibin subunit beta B (IHBB) and vascular endothelial growth factor A (VEGFA) mRNA in SCCs were quantified by RT-qPCR. The results demonstrated that the molecular weight of the purified dog and cat anti-FSHr antibody fragment was 25 kDa and 15 kDa, respectively. Based on protein molecular weight, the antibody fragment of dogs and cats was therefore, so-called single-chain variable fragments (scFv) and nanobody (nb), respectively. The binding affinity with dissociation constant (KD) was 2.32 × 10-7 M and 2.83 × 10-9 M for dog and cat anti-FSHr antibody fragments, respectively. The cross-binding kinetic interactions between the dog anti-FSHr scFv and the cat ECD of FSHr could not be fitted to the curves to determine the binding kinetics. However, the cross-binding affinity KD between the cat anti-FSHr nb and the dog ECD FSHr was 1.75 × 10-4 M. The mRNA expression of ABP, IHBB and VEGFA in SCCs was less (P < 0.05) in both dogs (12.26, 4.07 and 5.11 folds, respectively) and cats (39.53, 14.07 and 20.29 folds, respectively) treated with anti-FSHr antibody fragments, indicating the Sertoli cell functions were suppressed. In conclusion, this study demonstrated the establishment of species-specific antibody fragments against FSHr in SCCs for dogs and cats. The fragment proteins illustrate potential to be developed as non-surgical contraceptive agent targeting FSHr in companion animals.

Development of a novel testis-on-a-chip that demonstrates reciprocal crosstalk between Sertoli and Leydig cells in testicular tissue

The reciprocal crosstalk between testicular Sertoli and Leydig cells plays a vital role in supporting germ cell development and maintaining testicular characteristics and spermatogenesis. Conventional 2D and the recent 3D assay systems fail to accurately replicate the dynamic interactions between these essential endocrine cells. Furthermore, most in vitro testicular tissue models lack the ability to capture the complex multicellular nature of the testis. To address these limitations, we developed a 3D multicellular testis-on-a-chip platform that effectively demonstrates the reciprocal crosstalk between Sertoli cells and the adjacent Leydig cells while incorporating various human testicular tissue constituent cells and various natural polymers infused with blood coagulation factors. Additionally, we identified SERPINB2 as a biomarker of male reproductive toxicity that is activated in both Sertoli and Leydig cells upon exposure to various toxicants. Leveraging this finding, we designed a fluorescent reporter-conjugated toxic biomarker detection system that enables both an intuitive and quantitative assessment of material toxicity by measuring the converted fluorescence intensity. By integrating this fluorescent reporter system into the Sertoli and Leydig cells within our 3D multicellular chip platform, we successfully developed a testis-on-chip model that can be utilized to evaluate the male reproductive toxicity of potential drug candidates. This innovative approach holds promise for advancing toxicity screening and reproductive research.

Functional role of autophagy in testicular and ovarian steroidogenesis

Autophagy is an evolutionarily conserved cellular recycling process that maintains cellular homeostasis. Despite extensive research in endocrine contexts, the role of autophagy in ovarian and testicular steroidogenesis remains elusive. The significant role of autophagy in testosterone production suggests potential treatments for conditions like oligospermia and azoospermia. Further, influence of autophagy in folliculogenesis, ovulation, and luteal development emphasizes its importance for improved fertility and reproductive health. Thus, investigating autophagy in gonadal cells is clinically significant. Understanding these processes could transform treatments for endocrine disorders, enhancing reproductive health and longevity. Herein, we provide the functional role of autophagy in testicular and ovarian steroidogenesis to date, highlighting its modulation in testicular steroidogenesis and its impact on hormone synthesis, follicle development, and fertility therapies.

Heme oxygenase 1 (HO1) regulates autophagy and apoptosis via the PI3K/AKT/mTOR signaling pathway of yak Sertoli cells

Successful male reproduction depends on healthy testes. Autophagy has been confirmed to be active during many cellular events associated with the testes. It is not only crucial for testicular spermatogenesis but is also an essential regulatory mechanism for Sertoli cell (SCs) ectoplasmic specialization integrity and normal function of the blood-testis-barrier. Hypoxic stress induces oxidative damage, apoptosis, and autophagy, negatively affecting the male reproductive system. Cryptorchidism is a common condition associated with infertility. Recent studies have demonstrated that hypoxia-induced miRNAs and their transcription factors are highly expressed in the testicular tissue of infertile patients. Heme oxygenase 1 (HO1) is a heat-shock protein family member associated with cellular antioxidant defense and anti-apoptotic functions. The present study found that the HO1 mRNA and protein are up-regulated in yak cryptorchidism compared to normal testes. Next, we investigated the expression of HO1 in the SCs exposed to hypoxic stress and characterized the expression of key molecules involved in autophagy and apoptosis. The results showed that hypoxic stress induced the upregulation of autophagy of SCs. The down-regulation of HO1 using siRNA increases autophagy and decreases apoptosis, while the over-expression of HO1 attenuates autophagy and increases apoptosis. Furthermore, HO1 regulates autophagy and apoptosis via the PI3K/AKT/mTOR signaling pathway. These results will be helpful for further understanding the regulatory mechanisms of HO1 in yak cryptorchidism.

The constructive and destructive impact of autophagy on both genders' reproducibility, a comprehensive review

Reproduction is characterized by a series of massive renovations at molecular, cellular, and tissue levels. Recent studies have strongly tended to reveal the involvement of basic molecular pathways such as autophagy, a highly conserved eukaryotic cellular recycling, during reproductive processes. This review comprehensively describes the current knowledge, updated to September 2022, of autophagy contribution during reproductive processes in males including spermatogenesis, sperm motility and viability, and male sex hormones and females including germ cells and oocytes viability, ovulation, implantation, fertilization, and female sex hormones. Furthermore, the consequences of disruption in autophagic flux on the reproductive disorders including oligospermia, azoospermia, asthenozoospermia, teratozoospermia, globozoospermia, premature ovarian insufficiency, polycystic ovarian syndrome, endometriosis, and other disorders related to infertility are discussed as well.Abbreviations: AKT/protein kinase B: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ATG: autophagy related; E2: estrogen; EDs: endocrine disruptors; ER: endoplasmic reticulum; FSH: follicle stimulating hormone; FOX: forkhead box; GCs: granulosa cells; HIF: hypoxia inducible factor; IVF: in vitro fertilization; IVM: in vitro maturation; LCs: Leydig cells; LDs: lipid droplets; LH: luteinizing hormone; LRWD1: leucine rich repeats and WD repeat domain containing 1; MAP1LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MTOR: mechanistic target of rapamycin kinase; NFKB/NF-kB: nuclear factor kappa B; P4: progesterone; PCOS: polycystic ovarian syndrome; PDLIM1: PDZ and LIM domain 1; PI3K: phosphoinositide 3-kinase; PtdIns3P: phosphatidylinositol-3-phosphate; PtdIns3K: class III phosphatidylinositol 3-kinase; POI: premature ovarian insufficiency; ROS: reactive oxygen species; SCs: Sertoli cells; SQSTM1/p62: sequestosome 1; TSGA10: testis specific 10; TST: testosterone; VCP: vasolin containing protein.

Impaired Testicular Function without Altering Testosterone Concentration Using an Anti-Follicular-Stimulating Hormone Receptor (Anti-FSHr) Single-Chain Variable Fragment (scFv) in Long-Tailed Macaques (Macaca fascicularis)

FSHr antibodies have been shown to inhibit the differentiation of spermatogonia to primary spermatocytes, resulting in infertility without a pathological effect on reproductive organs. The aim of this study was to develop single-chain variable fragments (scFvs) against the follicular-stimulating hormone receptor (anti-FSHr) using phage-display technology and to evaluate the effects of intratesticular administration of the anti-FSHr scFv on testicular function and testosterone production. A phage clone against the extracellular domain of FSHr selected from a scFv phagemid library was analyzed for binding kinetics by surface plasmon resonance. Using ultrasound guidance, three adult macaques (M. fascicularis) were administered with 1 mL of 0.4 mg/mL anti-FSHr scFv (treatment) and 1 mL sterile phosphate buffer solution (control) into the left and right rete testis, respectively. Testicular appearance and volume, ejaculate quality, and serum testosterone levels were recorded on day 0 (before injection) and on days 7, 28, and 56 (after injection). Testicular tissue biopsies were performed on day 7 and day 56 to quantify the mRNA expressions of androgen binding protein (ABP), inhibin subunit beta B (IHBB), and vascular endothelial growth factor A (VEGFA). The results demonstrated that the anti-FSHr scFv molecule was calculated as 27 kDa with a dissociation constant (K_D) of 1.03 µM. The volume of the anti-FSHr scFv-injected testicle was reduced on days 28 and 56 compared with day 0 (p < 0.05). Total sperm number was reduced from day 0 (36.4 × 10⁶ cells) to day 56 (1.6 × 10⁶ cells) (p < 0.05). The percentage of sperm motility decreased from day 0 (81.7 ± 1.0%) to day 7 (23.3 ± 1.9%), day 28 (41.7 ± 53.4%), and day 56 (8.3 ± 1.9%) (p < 0.05). Sperm viability on day 0 was 86.8 ± 0.5%, which reduced to 64.2 ± 1.5%, 67.1 ± 2.2%, and 9.3 ± 1.1% on days 7, 28, and 56, respectively (p < 0.05). The expression of ABP and VEGFA on days 7 (14.2- and 3.2-fold) and 56 (5.6- and 5.5-fold) was less in the scFv-treated testicle compared with the controls (p < 0.05). On day 56, the expression of IHBB was less (p < 0.05) in the treated testis (1.3-fold) compared with the controls. Serum testosterone levels were unchanged throughout the study period (p > 0.05). This study characterized the anti-FSHr scFv and demonstrated that treatment with anti-FSHr ameliorates testicular function without altering testosterone levels, offering a potential alternative contraceptive for the long-tailed macaques.

Role of Macroautophagy in Mammalian Male Reproductive Physiology

Physiologically, autophagy is an evolutionarily conserved and self-degradative process in cells. Autophagy carries out normal physiological roles throughout mammalian life. Accumulating evidence shows autophagy as a mechanism for cellular growth, development, differentiation, survival, and homeostasis. In male reproductive systems, normal spermatogenesis and steroidogenesis need a balance between degradation and energy supply to preserve cellular metabolic homeostasis. The main process of autophagy includes the formation and maturation of the phagophore, autophagosome, and autolysosome. Autophagy is controlled by a group of autophagy-related genes that form the core machinery of autophagy. Three types of autophagy mechanisms have been discovered in mammalian cells: macroautophagy, microautophagy, and chaperone-mediated autophagy. Autophagy is classified as non-selective or selective. Non-selective macroautophagy randomly engulfs the cytoplasmic components in autophagosomes that are degraded by lysosomal enzymes. While selective macroautophagy precisely identifies and degrades a specific element, current findings have shown the novel functional roles of autophagy in male reproduction. It has been recognized that dysfunction in the autophagy process can be associated with male infertility. Overall, this review provides an overview of the cellular and molecular basics of autophagy and summarizes the latest findings on the key role of autophagy in mammalian male reproductive physiology.

Autophagy: A Double-Edged Sword in Male Reproduction

Autophagy, an evolutionarily conserved cell reprogramming mechanism, exists in all eukaryotic organisms. It is a fundamental and vital degradation/recycling pathway that removes undesirable components, such as cytoplasmic organelles, misfolded proteins, viruses, and intracellular bacteria, to provide energy and essential materials for organisms. The success of male reproduction depends on healthy testes, which are mainly composed of seminiferous tubules and mesenchyme. Seminiferous tubules are composed of Sertoli cells (SCs) and various germ cells, and the main functional part of mesenchyme are Leydig cells (LCs). In recent years, a large amount of evidence has confirmed that autophagy is active in many cellular events associated with the testes. Autophagy is not only important for testicular spermatogenesis, but is also an essential regulatory mechanism for the ectoplasmic specialization (ES) integrity of SCs, as well as for the normal function of the blood-testes barrier (BTB). At the same time, it is active in LCs and is crucial for steroid production and for maintaining testosterone levels. In this review, we expanded upon the narration regarding the composition of the testes; summarized the regulation and molecular mechanism of autophagy in SCs, germ cells, and LCs; and concluded the roles of autophagy in the process of spermatogenesis and testicular endocrinology. Through integrating the latest summaries and advances, we discuss how the role of autophagy is a double-edged sword in the testes and may provide insight for future studies and explorations on autophagy in male reproduction.

Eugenol reduces serum testosterone levels and sperm viability in adult Wistar rats

Eugenol is the main constituent of clove extract. It is a remarkably versatile molecule incorporated as a functional ingredient in several food products and widely applied in the pharmaceutical industry. Men consume natural products enriched with eugenol for treating sexual disorders and using as aphrodisiacs. Nevertheless, there is no information about the impact of eugenol intake on the reproductive parameters of healthy males. Therefore, we provided 10, 20, and 40 mg kg^-1 pure eugenol to adult Wistar rats for 60 days. Testis, epididymis, and spermatozoa were analyzed under microscopic, biochemical, and functional approaches. This phenolic compound did not alter testicular and epididymal biometry and microscopy. However, 20 and 40 mg kg^-1 eugenol reduced serum testosterone levels. The highest dose altered lactate and glucose concentrations in the epididymis. All the eugenol concentrations diminished CAT activity and MDA levels in the testis and increased FRAP and CAT activity in the epididymis. Epididymal sperm from rats receiving 10, 20, and 40 mg kg^-1 eugenol presented high Ca²⁺ ATPase activity and low motility. In conclusion, eugenol at low and high doses negatively impacted the competence of epididymal sperm and modified oxidative parameters in male organs, with no influence on their microscopy.

Dihydrotestosterone through blockade of TGF-β/Smad signaling mediates the anti-fibrosis effect under hypoxia in canine Sertoli cells

The hypoxic microenvironment of cryptorchidism is an important factor to induce the impairment of the structure and function of Sertoli cells and thus lead to spermatogenesis loss or tumorigenesis. Dihydrotestosterone (DHT), as a potent nonaromatizable 5α-reduced androgen, has both positive and negative effect on pathological fibrosis process. However, it is still unknown whether DHT can regulate hypoxia-induced fibrosis of Sertoli cells. Herein, in this study, we evaluate the DHT level, two 5α-reductase isoforms, 5α-red1 and 5α-red2, as well as HIF-1α expression pattern in canine cryptorchidism and contralateral normal testis. Results showed that the abdominal testes presented low DHT levels and 5α-red1 and 5α-red2 expression, while significantly higher HIF-1α expression and ECM production compared with the scrotum. Moreover, we established a hypoxia-induced fibrosis model in canine Sertoli cells induced by cobalt chloride (CoCl₂), and found that DHT inhibited the fibrosis of Sertoli cells in a dose-dependent manner. Meanwhile, DHT interfered with the TGF-β signaling by reducing the expression of TGF-βRI and TGF-βRII and inhibiting the expression and phosphorylation of Smad2 and Smad3, while flutamide (androgen receptor inhibitor) inhibited these effects of DHT. Furthermore, use of LY2109761 (TGF-β receptor type I/II inhibitor) to interfere with the TGF-β/Smad pathway showed a similar effect with DHT suppression of the fibrosis in Sertoli cells. Our research data demonstrated that cryptorchidism is located in a hypoxic and DHT deficiency microenvironment. Moreover, supplementing DHT can alleviate the fibrosis process of Sertoli cells caused by hypoxia, which is associated with AR regulating the inhibition of TGF-β/Smad signaling.

FSH inhibits autophagy and lysosomal biogenesis to regulate protein degradation in cultured goat Sertoli cells

Although the follicle-stimulating hormone (FSH) plays a vital role in male reproduction, the molecular relationships among FSH, autophagy, and the secretory function of Sertoli cells remain largely undetermined. In this study, we sought to investigate the effects of FSH on dairy goat Sertoli cell autophagy and the role of autophagy in protein clearance. FSH treatment of primary Sertoli cells was found to enhance the expression level of LC3-II, reduce p62 degradation and the number of lysosomes, and downregulate the levels of LAMP2 protein and lysosomal gene mRNAs. Further analyses revealed that starvation-induced autophagy promotes the translocation of transcription factor EB (TFEB) from the cytoplasm to nucleus and its binding to the promoter region of LAMP2, whereas FSH suppresses the nuclear translocation of TFEB. Moreover, we found that the FSH-mediated inhibition of autophagy extends the biological half-lives of androgen-binding protein (ABP), glial-derived neurotrophic factor (GDNF), and stem cell factor (SCF) and promotes the secretion of these proteins. Collectively, these observations indicate that FSH inhibits autophagy by reducing lysosomal biogenesis, which is associated with the suppression of TFEB nuclear translocation via activation of the PI3K/Akt/mTOR pathway, thereby extending the biological half-lives and enhancing the expression of ABP, GDNF, and SCF in dairy goat Sertoli cells.

Autophagy: a multifaceted player in the fate of sperm

BACKGROUND

Autophagy is an intracellular catabolic process of degrading and recycling proteins and organelles to modulate various physiological and pathological events, including cell differentiation and development. Emerging data indicate that autophagy is closely associated with male reproduction, especially the biosynthetic and catabolic processes of sperm. Throughout the fate of sperm, a series of highly specialized cellular events occur, involving pre-testicular, testicular and post-testicular events. Nonetheless, the most fundamental question of whether autophagy plays a protective or harmful role in male reproduction, especially in sperm, remains unclear.

OBJECTIVE AND RATIONALE

We summarize the functional roles of autophagy in the pre-testicular (hypothalamic–pituitary–testis (HPG) axis), testicular (spermatocytogenesis, spermatidogenesis, spermiogenesis, spermiation) and post-testicular (sperm maturation and fertilization) processes according to the timeline of sperm fate. Additionally, critical mechanisms of the action and clinical impacts of autophagy on sperm are identified, laying the foundation for the treatment of male infertility.

SEARCH METHODS

In this narrative review, the PubMed database was used to search peer-reviewed publications for summarizing the functional roles of autophagy in the fate of sperm using the following terms: ‘autophagy’, ‘sperm’, ‘hypothalamic–pituitary–testis axis’, ‘spermatogenesis’, ‘spermatocytogenesis’, ‘spermatidogenesis’, ‘spermiogenesis’, ‘spermiation’, ‘sperm maturation’, ‘fertilization’, ‘capacitation’ and ‘acrosome’ in combination with autophagy-related proteins. We also performed a bibliographic search for the clinical impact of the autophagy process using the keywords of autophagy inhibitors such as ‘bafilomycin A1’, ‘chloroquine’, ‘hydroxychloroquine’, ‘3-Methyl Adenine (3-MA)’, ‘lucanthone’, ‘wortmannin’ and autophagy activators such as ‘rapamycin’, ‘perifosine’, ‘metformin’ in combination with ‘disease’, ‘treatment’, ‘therapy’, ‘male infertility’ and equivalent terms. In addition, reference lists of primary and review articles were reviewed for additional relevant publications. All relevant publications until August 2021 were critically evaluated and discussed on the basis of relevance, quality and timelines.

OUTCOMES

(i) In pre-testicular processes, autophagy-related genes are involved in the regulation of the HPG axis; and (ii) in testicular processes, mTORC1, the main gate to autophagy, is crucial for spermatogonia stem cell (SCCs) proliferation, differentiation, meiotic progression, inactivation of sex chromosomes and spermiogenesis. During spermatidogenesis, autophagy maintains haploid round spermatid chromatoid body homeostasis for differentiation. During spermiogenesis, autophagy participates in acrosome biogenesis, flagella assembly, head shaping and the removal of cytoplasm from elongating spermatid. After spermatogenesis, through PDLIM1, autophagy orchestrates apical ectoplasmic specialization and basal ectoplasmic specialization to handle cytoskeleton assembly, governing spermatid movement and release during spermiation. In post-testicular processes, there is no direct evidence that autophagy participates in the process of capacitation. However, autophagy modulates the acrosome reaction, paternal mitochondria elimination and clearance of membranous organelles during fertilization.

WIDER IMPLICATIONS

Deciphering the roles of autophagy in the entire fate of sperm will provide valuable insights into therapies for diseases, especially male infertility.

Changes in histology, protein expression, and autophagy in dairy goat testes during nonbreeding season†

Seasonal reproduction contributes to increased chances of offspring survival in some animals. Dairy goats are seasonal breeding mammals. In this study, adult male Guanzhong dairy goats (10-12 months old) were used. Testis size, semen quality, hormone level, apoptosis of germ cells, and autophagy of Sertoli cells were analyzed in dairy goats during the breeding (October) and nonbreeding (April) seasons. We found that, during the nonbreeding season for dairy goats, semen quality, follicle-stimulating hormone (FSH) levels, and testosterone levels were reduced, and the number of apoptotic germ cells increased. The proliferation with decrease activity of germ cells in dairy goat during the nonbreeding season was significantly affected. However, the testis size did not change seasonally. Interestingly, Sertoli cell autophagy was more active during the nonbreeding season. The expression levels of FSH receptor, wilms tumor 1, androgen binding protein, glial cell derived neurotrophic factor, and stem cell factor decreased in dairy goats during the nonbreeding season. In summary, our results indicate that spermatogenesis in dairy goats during the nonbreeding season was not completely arrested. In addition, germ cell apoptosis and the morphology of Sertoli cells considerably changed in dairy goats during the nonbreeding season. Sertoli cell autophagy is involved in the seasonal regulation of spermatogenesis in dairy goats. These findings provide key insights into the fertility and spermatogenesis of seasonal breeding animals.

Busulfan impairs blood-testis barrier and spermatogenesis by increasing noncollagenous 1 domain peptide via matrix metalloproteinase 9

BACKGROUNDS

Sterility induced by anti-cancer treatments has caused significant concern, yet the mechanism and treatment exploration are little for male infertility after cancer therapy. Busulfan, the antineoplastic that was widely applied before bone marrow transplantation, was known to induce male reproductive disorder.

OBJECTIVES

To investigate the effect of busulfan on blood-testis barrier function in adult rats and determine whether noncollagenous 1 domain peptide, the biologically active fragment proteolyzed from the collagen α3 chain (IV) by matrix metalloproteinase 9, was involved during this process.

MATERIALS AND METHODS

Adult male rats were treated with one-dose or double-dose of busulfan (10 mg/kg) before euthanized at day 35. Blood-testis barrier integrity assay, HE staining, immunofluorescence, and Western blot were used to validate the effect of busulfan on blood-testis barrier permeability and spermatogenesis. JNJ0966 was applied to specifically inhibit the matrix metalloproteinase 9 activity. The polymerization activity of F-actin/G-actin and microtubule/tubulin in the testis were assessed by using commercial kits.

RESULTS

A noteworthy blood-testis barrier injury and significant up-regulation of matrix metalloproteinase 9 activity and noncollagenous 1 level after a single-dose busulfan (10 mg/kg) treatment in adult rat testis were revealed. The application of JNJ0966 was found to decrease noncollagenous 1 level and rescue the busulfan-induced blood-testis barrier injury including the mis-localization of junction proteins across the seminiferous epithelium, by recovering the organization and polymerization of both F-actin and microtubule. The busulfan-induced spermatogenesis impairment was also improved by JNJ0966.

CONCLUSION

These findings thus demonstrate that the elevation in matrix metalloproteinase 9 and noncollagenous 1 might participate in busulfan-induced blood-testis barrier disruption in adult male rats. As such, busulfan-induced male infertility could possibly be managed through interventions on noncollagenous 1 production.

The Effect of Soy Milk on Mounting Latency, Mounting Frequency, and Reproductive Development in Male Wistar Rats (Rattus Norvegicus)

AIM: This research aims to examine the effects of soy milk on mounting latency (ML), mounting frequency (MF), estrogen levels, androgen-binding protein (ABP) expression, and spermatogenesis in male rats (Rattus norvegicus). METHODS: Twenty-four male wistar rats (Rattus norvegicus) aged 4 weeks were divided into four groups. Control group (given a normal diet), P1; P2; P3 (given the normal diet and soy milk powder at doses of 7.1; 14.2; 21.3 g/KgBW/day, respectively) for 6 weeks. Observation of ML and MF were performed at 9 weeks 5 days of age, and rat surgery was performed at 10 weeks of age. Analysis of estrogen hormone levels was conducted by enzyme-linked immunosorbent assay (ELISA), ABP staining was using immunohistochemistry method, testicular spermatogenesis was observed using histopathological methods, and observation of spermatozoa was performed under the microscope.  RESULTS: The results showed no significant reduction of ML and MF, estrogen levels, and ABP expression (p ≤ 0.256; 0.865; 0.959, respectively) in male rat, but there was a significant decrease in the number, morphology, motility of spermatozoa, and testicular histophatology, (p ≤ 0.000, 0.003, 0.008, 0.000, respectively). CONCLUSION: The administrassion of soy milk in various doses (7.1;14.2;21.3 g/KgBW/day) in male Wistar rats (Rattus norvegicus) had showed significantly difference on histopathological evaluation using Johnson’s scoring system, sperm quantity and quality, while on mounting latency and frequency, estrogen levels, and ABP expressions did not show significantly difference between groups. That describe of isoflavone in soy milk can affect several aspects related to male endocrine and reproductive development.

MERTK-Mediated LC3-Associated Phagocytosis (LAP) of Apoptotic Substrates in Blood-Separated Tissues: Retina, Testis, Ovarian Follicles

Timely and efficient elimination of apoptotic substrates, continuously produced during one’s lifespan, is a vital need for all tissues of the body. This task is achieved by cells endowed with phagocytic activity. In blood-separated tissues such as the retina, the testis and the ovaries, the resident cells of epithelial origin as retinal pigmented epithelial cells (RPE), testis Sertoli cells and ovarian granulosa cells (GC) provide phagocytic cleaning of apoptotic cells and cell membranes. Disruption of this process leads to functional ablation as blindness in the retina and compromised fertility in males and females. To ensure the efficient elimination of apoptotic substrates, RPE, Sertoli cells and GC combine various mechanisms allowing maintenance of tissue homeostasis and avoiding acute inflammation, tissue disorganization and functional ablation. In tight cooperation with other phagocytosis receptors, MERTK—a member of the TAM family of receptor tyrosine kinases (RTK)—plays a pivotal role in apoptotic substrate cleaning from the retina, the testis and the ovaries through unconventional autophagy-assisted phagocytosis process LAP (LC3-associated phagocytosis). In this review, we focus on the interplay between TAM RTKs, autophagy-related proteins, LAP, and Toll-like receptors (TLR), as well as the regulatory mechanisms allowing these components to sustain tissue homeostasis and prevent functional ablation of the retina, the testis and the ovaries.

Extracellular vesicles in the male reproductive tract of the softshell turtle

Extracellular vesicles (EVs) are a heterogeneous group of cell-derived membranous structures comprising exosomes and microvesicles that originate from the endosomal system or are shed from the plasma membrane respectively. As mediators of cell communication, EVs are present in biological fluids and are involved in many physiological and pathological processes. The role of EVs has been extensively investigated in the mammalian male reproductive tract, but the characteristics and identification of EVs in reptiles are still largely unknown. In this review we focus our attention on EVs and their distribution in the male reproductive tract of the Chinese softshell turtle Pelodiscus sinensis , mainly discussing the potential roles of EVs in intercellular communication during different phases of the reproductive process. In softshell turtles, Sertoli-germ cell communication via multivesicular bodies can serve as a source of EVs during spermatogenesis, and these EVs interact with epithelia of the ductuli efferentes and the principal cells of the epididymal epithelium. These EVs are involved in sperm maturation, transport and storage. EVs are also shed by telocytes, which contact and exchange information with other, as well as distant interstitial cells. Overall, EVs play an indispensable role in the normal reproductive function of P. sinensis and can be used as an excellent biomarker for understanding male fertility.

Autophagy in Sertoli cell protects against environmental cadmium-induced germ cell apoptosis in mouse testes

Cadmium (Cd) was an environmental pollutant, which could result in germ cell apoptosis in testes. Sertoli-germ cell communication was vital for germ cell development and maturity. However, little was known about the effect of Sertoli cell autophagy on Cd-induced germ cell apoptosis. Here, we used male Amh-Cre+/Atg5^flox/flox (Atg5^-/-) mice, loss of autophagy-related gene 5 (Atg5) in testicular Sertoli cells, to explore the obscure effects. Atg5^-/- and Wild-type (WT) mice were given with cadmium chloride (CdCl_2, 2.0 mg/kg) for 0-24 h. Our results showed that Cd triggered testicular germ cell apoptosis, as evidenced by the increment of TUNEL-labeled germ cells, cleaved caspase3 and cleaved poly (ADP-ribose) polymerase protein level. Additionally, Cd induced testicular autophagy, as determined by elevating the level of autophagy-related proteins, including Atg5, Atg7, LC3B-II, and the gathering of LC3 puncta. 3-methyladenine, a specific autophagy inhibitor, exacerbated Cd-caused germ cell apoptosis. Inversely, rapamycin, an autophagy inducer, relieved Cd-stimulated germ cell apoptosis. Interestingly, we found that autophagy in Sertoli cells was activated in Cd-treated WT mouse testes as evidenced by the increment of LC3 puncta surrounding SOX9, a specific Sertoli cell marker. More importantly, loss of autophagy in Sertoli cells aggravated Cd-triggered germ cell apoptosis. Taken together, these data indicate that autophagy in Sertoli cells alleviates Cd-triggered germ cell apoptosis in mouse testes.

Seminal exosomal miR-210-3p as a potential marker of Sertoli cell damage in Varicocele

BACKGROUND

Varicocoele-associated stressors, such as hypoxia and heat, can damage cell function and viability, and some exosomal biomarkers released from impaired cells may reflect the cell status in testis.

OBJECTIVES

To find if seminal exosomal microRNAs can reflect the Sertoli cell function in varicocoele.

MATERIALS AND METHODS

Experimental left varicocoele rat model was established (n = 24), and patients with different grades of varicocoele (n = 104) were enrolled. Primary rat Sertoli cells were isolated with enzymatic hydrolysis. Exosomes were isolated from primary rat Sertoli cells, rat epididymis tissue, and human seminal plasma with polymer-based precipitation method. Exosomal microRNAs were quantified with qPCR. Inhibin-B was detected with enzyme immunoassay. The correlation analysis between microRNA and inhibin-B was evaluated with Spearman's correlation.

RESULTS

We screened 12 previously reported hypoxia-responsive microRNAs in the primary rat Sertoli cells and found that 4 exosomal microRNAs increased significantly in response to in vitro hypoxia treatment (P < .05). Of the 4 microRNAs, only miR-210-3p was upregulated in the rats with experimental varicocoele (P < .01). In the patients with varicocoele, we found that seminal exosomal miR-210-3p significantly increased in patients with grade II and III varicocoele (P < .01), and miR-210-3p negatively correlated with sperm count (P < .01) and seminal inhibin-B expression (r = -0.39, P < .01). For the 30 patients with microsurgical varicocelectomy, the operation notably decreased miR-210-3p (P < .01).

DISCUSSION AND CONCLUSION

Seminal exosomal miR-210-3p may be a novel, sensitive, and non-invasive biomarker of Sertoli cell damage in varicocoele.

Role of AURKA in the hypothalamus-pituitary-testicular axis in Tibetan sheep from Tianzhu

The mitosis-associated protein aurora kinase A (AURKA) regulates the maturation of germ cells. We have previously reported using transcriptome analysis that AURKA is expressed in yak testes. Although Tibetan sheep possess an immense economic value, their reproductive rate is low. Herein, the expression and functions of AURKA in the hypothalamus-pituitary-testicular (HPT) axis in Tibetan sheep from Tianzhu were investigated. The cDNA sequence of sheep AURKA was cloned and bioinformatics techniques were used to predict its structure. Tissue expression of AURKA was determined by qPCR, immunoblotting, immunostaining, and immunohistochemistry. The AURKA coding sequence was found to be 1218 bp in length, encoding a 405-amino acid polypeptide chain. Furthermore, the highest sequence similarity of AURKA with the corresponding sequence in other species was seen in goat and cattle; the least degree of similarity was seen in the domestic cat. In addition, AURKA expression was elevated in the testes compared to that in the hypothalamus and pituitary (p < 0.01). Moreover, AURKA was mainly localized in the hypothalamic paraventricular nucleus (magnocellular), chromophobe cells of the pituitary, and spermatogenic cells of the testis. These results indicated that AURKA might participate in sheep reproductive regulation, thus providing a reference for the study of AURKA function in the reproductive process of Tibetan sheep from Tianzhu.

The effects of sacubitril/valsartan and ramipril on the male fertility in hypertensive rats

OBJECTIVE:

Renin angiotensinogen system (RAS) inhibitors, ramipril and sacubitril/valsartan are frequently used in the treatment of cardiovascular diseases. Although they are known as contraindicated during pregnancy in hypertensive women, there is not any outcome of their safety in male fertility after exposure to ramipril or sacubitril/valsartan. In this study, we aimed to evaluate the effects of ramipril and sacubitril/valsartan to highlight their safety in the male fertility in normotensive and hypertensive rats.

METHODS:

Adult male normotensive and dexamethasone-induced hypertensive rats were treated with sacubitril/valsartan, ramipril and saline for 18 days. Arterial blood pressures were verified using carotid artery cannulation. Male fertility parameters, including the testis weights, histopathologic scoring of the testis, sperm count, sperm motility, morphology, and serum testosterone levels, were analyzed in treated and nontreated normotensive/hypertensive rats.

RESULTS:

Sacubitril/valsartan or ramipril treatments did not reveal a significant difference in sperm production, testicular morphology, and radioimmunoassay of serum testosterone levels compared to the control group. However, sperm motility was significantly reduced in rats under RAS inhibition.

CONCLUSION:

This finding was likely mediated by the identification of Ang receptors in the tails of rat sperm given that Ang receptors may play a role in the modulation of sperm motility. Identification of RAS-related proteins involved in sperm motility may help to explain their roles in motility. Our data provide general safety evidence for the male fertilization ability after paternal sacubitril/valsartan and ramipril exposure.

Reproductive responses of the male Brandt’s vole, Lasiopodomys brandtii (Rodentia: Cricetidae) to tannic acid

Tannins are polyphenols that are present in various plants, and potentially contain antioxidant properties that promote reproduction in animals. This study investigated how tannic acid (TA) affects the reproductive parameters of male Brandt’s voles,Lasiopodomys brandtii(Radde, 1861). Specifically, the anti-oxidative level of serum, autophagy in the testis, and reproductive physiology were assessed in males treated with TA from the pubertal stage. Compared to the control, low dose TA enhanced relative testis and epididymis weight and sperm concentration in the epididymis, and significantly increased the level of serum superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). mRNA levels of autophagy related genes LC3 and Beclin1 decreased significantly with low dose TA compared to the control. However, compared to the control, high dose TA sharply reduced the levels of serum SOD, GSH-Px, CAT, serum testosterone (T), and mRNA level in steroidogenic acute regulatory protein (StAR) in the testis. Both sperm abnormality and mortality increased with high dose TA compared to the control and low dose TA. Collectively, this study demonstrated that TA treatment during puberty had a dose-dependent effect on the reproductive responses of male Brandt’s voles. TA might mediate autophagy in the testis, through both indirect and direct processes. TA mainly affected the reproductive function of male Brandt’s voles by regulating anti-oxidative levels. This study advances our understanding of the mechanisms by which tannins influence reproduction in herbivores.

Hair growth promotion by necrostatin-1s

Necrostatins (Necs) have been developed as a receptor-interacting protein kinase 1 (RIPK1) inhibitor, thus inhibiting necroptosis. In this current study, we have investigated the possible involvement of necroptosis in the hair cycle regulation and further examined its underlying molecular mechanisms. Diverse RIPK1/3 inhibitors and siRNA were tested in the human outer-root sheath (ORS) cells and animal models. The expression and hair cycle-dependent expression of RIPK 1, respectively, were investigated in the hair follicles (HF) of human, pig, and the mouse. Resulting from the experiment, Nec-1s was most effective in the hair growth promotion among several inhibitors. Nec-1s induced the ORS cell proliferation and migration, and increased the HF length in mouse and pig organ cultures. In addition, it accelerated the telogen-to-anagen transition and elongated the anagen period in the mouse model. Both apoptosis and necroptosis were detected in hair cycle. RIPK1 and RIPK3 were highly expressed in ORS cells during the hair regression period. Nec-1s upregulated the mRNA expression of Wnt3a and Wnt5b, and the activity of β-catenin. Collectively, Nec-1s promotes hair growth through inhibiting necroptosis and activating the Wnt/β-catenin pathway. Necroptosis is involved in hair cycle regression, and Nec-1s is a promising target for hair-loss treatment.

Inhibition of p97/VCP function leads to defective autophagosome maturation, cell cycle arrest and apoptosis in mouse Sertoli cells

p97/valosin-containing protein (VCP) is expressed in many cells and plays critical functions in a broad range of diverse cellular processes. Because it is expressed in the mouse testes, predominantly in Sertoli cells, and is known to play a critical role in autophagy and apoptosis in different cell types, we set out to investigate its function in autophagosome maturation, apoptosis and cell cycle arrest in a mouse Sertoli cell line. To study the mechanism of p97/VCP action, p97/VCP siRNA and a specific p97/VCP inhibitor, N²,N⁴-dibenzylquinazoline-2,4-diamine (DBeQ), were used in the mouse 15P1 Sertoli cell line. Loss of p97/VCP activity due to DBeQ exposure and silencing of p97/VCP (siVCP) expression results in autophagosome (LC3 and p62) accumulation in the cytoplasm of Sertoli cells. The coexpression of autophagosomal and lysosomal markers (LAMP1 and LAMP2) was reduced in cells in which p97/VCP expression had been inactivated. To better understand in which step of autophagy p97/VCP functions, the interaction between autophagosomal and autolysosomal markers was studied by coimmunoprecipitation and colocalization experiments. The interaction between autophagosomal markers and lysosomal markers decreased in siVCP-expressing and DBeQ-exposed cells. Moreover, the expression of siVCP and DBeQ exposure caused cytoplasmic vacuolation, induced caspase 3-7-mediated cell death and decreased cell cycle progression in mouse Sertoli cells. Taken together, the results show that p97/VCP is essential for autophagosome maturation and cell survival in mouse Sertoli cells. When these functions are prevented, impaired autophagy and apoptosis may have a detrimental effect on germ cells and cause male infertility.

Possible protective role of 17β-estradiol against COVID-19

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is the virus that causes coronavirus disease 2019 (COVID-19); a worldwide pandemic as declared by the World Health Organization (WHO). SARS-CoV-2 appears to infect cells by first binding and priming its viral-spike proteins with membrane-associated angiotensin-converting enzyme 2 (ACE2) and transmembrane protease serine 2 (TMPRSS2). Through the coordinated actions of ACE2 and TMPRSS2, SARS-CoV-2 spike proteins fuse with plasma membranes and ultimately the virus enters cells. ACE2 is integral to the renin-angiotensin-aldosterone system (RAAS), and SARS-CoV-2 down-regulates protein expression levels of ACE2. Once infected, patients typically develop acute respiratory distress syndrome (ARDS) and a number of other severe complications that result in a high rate of fatality, especially in older (>60 years) adults and in people with pre-existing medical conditions. Data now indicate clearly that among people of all age groups, COVID-19 fatalities are higher in men than women. Here, attention is focused on these sex differences and posit a role of estrogen in these differences as well as possible therapeutic and protective actions of 17β-estradiol against COVID-19.

Prenatal exposure to excess chromium attenuates transcription factors regulating expression of androgen and follicle stimulating hormone receptors in Sertoli cells of prepuberal rats

We have reported that gestational exposure to hexavalent chromium (CrVI) represses androgen receptor (Ar) and follicle stimulating hormone receptor (Fshr) in Sertoli cells (SCs) of adult rats, while the mechanism underlying remains obscure. We tested the hypothesis "transient gestational exposure to CrVI during the critical embryonic windows of testicular differentiation and growth may have adverse impact on transcription factors controlling the expression of Ar and Fshr in SCs of the F₁ progeny". CrVI (K₂Cr₂O₇) was given through drinking water (50 ppm, 100 ppm and 200 ppm), to pregnant rats from gestational day 9-14 (testicular differentiation) and 15 to 21 (prenatal differentiation and proliferation of SC); male progenies were sacrificed on postnatal day 30 (Completion of postnatal SC maturation). A significant increase in free radicals and decrease in enzymatic and non-enzymatic antioxidants were observed in SCs of experimental rats. Real time PCR and western blot data showed decreased expression of Ar, Fshr, Inhibin B, Transferrin, Androgen binding protein, Claudin 11 and Occludin in SCs of experimental rats; concentrations of lactate, pyruvate and retinoic acid also decreased. Serum FSH, luteinizing hormone and estradiol increased, whereas testosterone and prolactin decreased in experimental rats. Western blot detection revealed decreased levels of transcription factors regulating Fshr viz., USF-1, USF-2, SF-1, c-fos, c-jun and GATA 1, and those of Ar viz., Sp-1, ARA54, SRC-1 and CBP in experimental rats, whereas the levels of cyclinD1 and p53, repressors of Ar increased. ChIP assay detected decreased USF-1 and USF-2 binding to Fshr promoter, and binding of Sp-1 to Ar promoter. We conclude that gestational exposure to CrVI affects SC structure and function in F₁ progeny by inducing oxidative stress and diminishing the expression of Ar and Fshr through attenuation of their specific transcriptional regulators and their interaction with the respective promoter.

Cellular evidence of autophagy in Sertoli cells during spermatogenesis in goats

Sertoli cells (SCs) play their nursing role as structural and functional supporting cells during spermatogenesis to ensure the production of highly specialized mature spermatozoa. Besides that, the role of SCs in autophagy during active (adult) and inactive (young) spermatogenesis in the caprine testis is still largely unknown. In this study, we investigated autophagy in goat SCs by light microscopy, immunohistochemistry (IHC), double immunofluorescence (double-IF), and transmission electron microscopy. Light microscopy showed active seminiferous tubules with SCs and layers of developing germ cells in the adult goat testis. In young goats, layer of germ cells and SCs was viewed on the basal membrane in the seminiferous tubule. IHC of autophagy-related 7 (ATG7) showed moderate expressions in the cytoplasmic extensions of SCs during inactive spermatogenesis, and strong expression was observed during active spermatogenesis in the testis of goat. Co-immunolabeling of p62 or light chain 3 (LC3) with vimentin showed increasing expression from the basal to the luminal compartment of the seminiferous tubule and stronger expression during active than inactive spermatogenesis in the testis of goat. Ultrastructure assessment of the cytoplasm in SCs showed phagophores, generated from the endoplasmic reticulum during active spermatocytogenesis. Numerous autophagosomes and autolysosomes were noted in the SCs cytoplasm, which surrounds the spermatogenic cells in the basal compartment of the seminiferous tubules. At a later stage, SCs showed autophagosomes and autolysosomes, together with multivesicular bodies (MVB), during spermiogenesis at different phases of the acrosome formation. Numerous embedded elongated spermatozoa were found in the cytoplasm of SCs, surrounded by autophagic components and MVB. Under TEM, the mean diameter of autophagosomes was 952.35 nm and that of autolysosomes was 504.38 nm. Collectively, these results suggest that autophagy is active in SCs during caprine spermatogenesis and that the level of autophagy becomes more evident as spermatogenesis advances from the basal to the luminal compartment of SC.

Tebuconazole and Econazole Act Synergistically in Mediating Mitochondrial Stress, Energy Imbalance, and Sequential Activation of Autophagy and Apoptosis in Mouse Sertoli TM4 Cells: Possible Role of AMPK/ULK1 Axis

Tebuconazole and Econazole are triazole and imidazole fungicides currently used worldwide. Although their reproductive toxicity in mammals has been described, their effect on male reproductive systems has been poorly investigated. As humans may be exposed to different azole compounds simultaneously, the combinational in vitro toxicity of Tebuconazole and Econazole (MIX) in mouse Sertoli TM4 cells was investigated. This study demonstrates that Tebuconazole (40 µM) and Econazole (20 µM) act synergistically in mediating decrease of mitochondrial membrane potential (ΔΨm) and changes in mitochondrial morphology. These events were associated with ATP depletion, cell cycle arrest, and sequential activation of autophagy and apoptosis. Remarkable differences on other parameters such as AMP/ATP ratio and adenylate energy charge were observed. Pharmacological inhibition of autophagy by bafilomycin A1 leads to enhanced MIX-induced apoptosis suggesting an adaptive cytoprotective function for MIX-modulated autophagy. Finally, a possible role of AMPK/ULK1 axis in mediating adaptive signalling cascades in response to energy stress was hypothesized. Consistently, ULK1 Ser 555 phosphorylation occurred in response to AMPK (Thr 172) activation. In conclusion, Tebuconazole and Econazole combination, at concentrations relevant for dermal and clinical exposure, induces a severe mitochondrial stress in SCs. Consequently, a prolonged exposure may affect the ability of the cells to re-establish homeostasis and trigger apoptosis.

miR-362 knock-down promotes proliferation and inhibits apoptosis in porcine immature Sertoli cells by targeting the RMI1 gene

Immature Sertoli cell proliferation determines the total number of mature Sertoli cells and further regulates normal spermatogenesis. Accumulating evidence demonstrates that microRNAs (miRNAs) play regulatory roles in immature Sertoli cell proliferation, while the functions and mechanisms of the Sertoli cells of domestic animals are poorly understood. In the present study, we aimed to investigate the roles of miR-362 in cell proliferation and apoptosis of porcine immature Sertoli cells. The results showed that miR-362 inhibition promoted the entrance of cells into the S phase and increased the expressions of cell cycle-related genes c-MYC, CNNE1, CCND1 and CDK4. Knock-down of miR-362 also promoted cell proliferation and inhibited apoptosis, which was demonstrated by the results from cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) and Annexin V-FITC/PI staining assays. The recQ-mediated genome instability protein 1 (RMI1) gene was identified as a potential target gene of miR-362 via luciferase reporter assay, and miR-362 repressed the protein expression of RMI1 in porcine immature Sertoli cells. siRNA-induced RMI1 knock-down further abolished the effects of miR-362 inhibition on porcine immature Sertoli cells. Collectively, we concluded that miR-362 knock-down promotes proliferation and inhibits apoptosis in porcine immature Sertoli cells by targeting the RMI1 gene, which indicates that miR-362 determines the fate of immature Sertoli cells.

Spectrophotometric and chromatographic strategies for exploring of the nanostructure pharmaceutical formulations which contains testosterone undecanoate

The nanostructure pharmaceutical formulations (NPF) which contains testosterone undecanoate (TU) been used in life science as parent compound delivery systems for therapeutic, but and been used to enhance the performance in sport, so it is a significant substance for public health and nutritional supplements. In most Pharmacopoeias testosterone is described as an ester of some lower acids (often propionate). The aim of this study is to determine purity of the parent compound by chromatography and absorption spectrum in the frame of middle infrared. Chemical structure of undecanoate was prepared and used in order to achieve a better absorption. This is explained by increased lipophilicity of undecanoate. Due to its lipophilic character, TU is soluble in non–polar solvents but shows a satisfactory solubility in absolute ethanol. Based on the molecular structure, a moderate absorption in the frame of UV with a maximum absorption at a not too high wave-length can be predicted. Maximum absorption occurs in a spectral region in which usual ingredients do not present significant interference.

Cellular Evidence of CD63-Enriched Exosomes and Multivesicular Bodies within the Seminiferous Tubule during the Spermatogenesis of Turtles

The seminiferous tubule (ST) is the location of spermatogenesis, where mature spermatozoa are produced with the assistance of Sertoli cells. The role of extracellular vesicles in the direct communication between Sertoli-germ cells in the ST is still not fully understood. In this study, we reported multivesicular bodies (MVBs) and their source of CD63-enriched exosomes by light and ultrastructure microscopy during the reproductive phases of turtles. Strong CD63 immunopositivity was detected at the basal region in the early and luminal regions of the ST during late spermatogenesis by immunohistochemistry (IHC), immunofluorescence (IF), and western blot (WB) analysis. Labeling of CD63 was detected in the Sertoli cell cytoplasmic processes that surround the developing germ cells during early spermatogenesis and in the lumen of the ST with elongated spermatids during late spermatogenesis. Furthermore, ultrastructure analysis confirmed the existence of numerous MVBs in the Sertoli cell prolongations that surround the round and primary spermatogonia during acrosome biogenesis and with the embedded heads of spermatids in the cytoplasm of Sertoli cells. Additionally, in spermatids, Chrysanthemum flower centers (CFCs) generated isolated membranes involved in MVBs and autophagosome formation, and their fusion to form amphiosomes was also observed. Additionally, autophagy inhibition by 3-methyladenine (after 24 h) increased CD63 protein signals during late spermatogenesis, as detected by IF and WB. Collectively, our study found MVBs and CD63 rich exosomes within the Sertoli cells and their response to autophagy inhibition in the ST during the spermatogenesis in the turtle.

NC1-peptide regulates spermatogenesis through changes in cytoskeletal organization mediated by EB1

During the epithelial cycle of spermatogenesis, different sets of cellular events take place across the seminiferous epithelium in the testis. For instance, remodeling of the blood-testis barrier (BTB) that facilitates the transport of preleptotene spermatocytes across the immunological barrier and the release of sperms at spermiation take place at the opposite ends of the epithelium simultaneously at stage VIII of the epithelial cycle. These cellular events are tightly coordinated via locally produced regulatory biomolecules. Studies have shown that collagen α3 (IV) chains, a major constituent component of the basement membrane, release the non-collagenous (NC) 1 domain, a 28-kDa peptide, designated NC1-peptide, from the C-terminal region, via the action of MMP-9 (matrix metalloproteinase 9). NC1-peptide was found to be capable of inducing BTB remodeling and spermatid release across the epithelium. As such, the NC1-peptide is an endogenously produced biologically active peptide which coordinates these cellular events across the epithelium in stage VIII tubules. Herein, we used an animal model, wherein NC1-peptide cloned into the pCI-neo mammalian expression vector was overexpressed in the testis, to better understanding the molecular mechanism by which NC1-peptide regulated spermatogenic function. It was shown that NC1-peptide induced considerable downregulation on a number of cell polarity and planar cell polarity (PCP) proteins, and studies have shown these polarity and PCP proteins modulate spermatid polarity and adhesion via their effects on microtubule (MT) and F-actin cytoskeletal organization across the epithelium. More important, NC1-peptide exerted its effects by downregulating the expression of microtubule (MT) plus-end tracking protein (+TIP) called EB1 (end-binding protein 1). We cloned the full-length EB1 cDNA for its overexpression in the testis, which was found to block the NC1-peptide-mediated disruptive effects on cytoskeletal organization in Sertoli cell epithelium and pertinent Sertoli cell functions. These findings thus illustrate that NC1-peptide is working in concert with EB1 to support spermatogenesis.

AMBRA1, Autophagy, and the Extreme Male Brain Theory of Autism

The extreme male brain theory of autism posits that its male bias is mediated by exaggeration of male-biased sex differences in the expression of autism-associated traits found in typical populations. The theory is supported by extensive phenotypic evidence, but no genes have yet been described with properties that fit its predictions. The autophagy-associated gene AMBRA1 represents one of the top genome-wide “hits” in recent GWAS studies of schizophrenia, shows sex-differential expression, and has been linked with autism risk and traits in humans and mice, especially or exclusively among females. We genotyped the AMBRA1 autism-risk SNP in a population of typical humans who were scored for the dimensional expression of autistic and schizotypal traits. Females, but not males, homozygous for the GG genotype showed a significant increase in score for the single trait, the Autism Quotient-Imagination subscale, that exhibits a strong, significant male bias in typical populations. As such, females with this genotype resembled males for this highly sexually dimorphic, autism-associated phenotype. These findings support the extreme male brain hypothesis and indicate that sex-specific genetic effects can mediate aspects of risk for autism.

Effects of phthalates on bovine primary testicular culture and spermatozoa

Among environmental endocrine-active chemicals, phthalates, commonly known as plasticizers, disrupt the development of the male reproductive tract. In this study, the effects of phthalates (DIBP, BBP, DINP, DBP, DEP, DEHP and DMP) were evaluated on cultures of bovine primary male reproductive cells (n = 3) and spermatozoa (n = 4). Epididymal (caput and corpus epididymis), testicular (parenchymal and mediastinal/tubular) and vas deferens cells (VDC) were prepared from samples collected from slaughterhouse. Second part of caput epididymis which have fewer amount of principal cells, were found to be less affected compared to the first part except DEHP; while corpus epididymis was found to be more affected with IC50 values below 0.976 ng/mL (except for DEP at 4.97 ng/mL). In testicular parenchymal cells, IC50 ranged from 0.15 to 4.11 ng/mL and for mediastinum from 0.01 to 7.31 ng/mL; where cytotoxic effects were more evident in mediastinal section. Least cytotoxic and even proliferational effects (DEHP, DMP and DEP) were observed in VDC, the muscular tube carrying sperm from epididymis to the ejaculatory duct. Least spermiotoxic phthalate was DBP (3.928 ng/mL); while DINP (0.550 ng/mL) induced highest cytotoxic effect on bovine spermatozoa. Differences in the cellular structure and/or the androgen receptor distribution effect the toxicity of phthalates. Our preliminary findings on bovine spermatozoa indicate possible morphological and motility alterations; which challenges further investigation of the transition of phthalates on semen straws used in cryopreservation. Increase of exposure to environmental contaminants raise the issue of the requirement of a new perspective on reproductive health, species and tissue specific differences should further be emphasized.

ULK1 affects cell viability of goat Sertoli cell by modulating both autophagy and apoptosis

Sertoli cells (SCs) are necessary for proper germ cell development and viability. Unc-51 like autophagy activating kinase (ULK1) protein kinase is an important regulator of autophagy activation. This study aims to investigate the role of autophagy promoter ULK1 on cell viability of goat SCs. Our results showed that ULK1 knockdown in goat SCs decreased autophagy activation, which was confirmed by decreased expression of autophagy-related markers including LC3, Beclin1, Atg5, and Atg7 (P < 0.05). Meanwhile, lower ULK1 levels resulted in decreased expressions of goat SC marker genes ABP, AMH, FASL, and GATA4. However, a reverse trend of these parameters occurred when the goat SCs were transfected with ULK1 overexpression construct; higher ULK1 levels in goat SCs also decreased the ratio of Bax/Bcl-2. Moreover, ULK1 overexpression in goat SCs activated the autophagy levels when cells were exposed to an environmental contaminant bisphenol A (BPA). The above results indicated that ULK1 gene might play important roles in goat SC function by regulating cell viability.

Autophagy in male reproduction

Autophagy is a fundamental process that exists in all eukaryotic organisms, with a primary function of catabolizing undesirable components to provide energy and essential materials. Increasing evidence illustrates that autophagy is invovled in a broad range of cellular events within the male reproductive system. In the process of spermatogenesis, autophagy is crucial for the formation of specific structures that guarantee successful spermatogenesis, as well as for the degradation of certain constituents. The underlying connections between autophagy and androgen binding protein, lipid metabolism and testosterone biosynthesis would increase our understanding of male testicular endocrinology. Moreover, cumulative studies reveal that autophagy is a double-edged sword when the organism suffers from endocrine disrupting chemicals. This review contains a collection of the current literature concerning the above aspects of autophagy, which may provide insights for future study and exploration. Abbreviations: 3-MA: 3-methyladenine; ABP: androgen-binding protein; AKT: protein kinase B; AMPK: adenosine monophosphate-activated protein kinase; ART: assisted reproductive technologies; Atg: autophagy-related gene; CE: cholesteryl ester; CL: corpus luteum; CQ: chloroquine; CYP11A1: cholesterol side chain cleavage enzyme; CytC: cytochrome C; DEHP: di-2-ethylhexyl phthalate; DFCP1: double FYVE-containing protein 1; EDCs: endocrine-disrupting chemicals; ERK1/2: extracellular signal-regulated kinase 1/2; ES: ectoplasmic specialization; FC: free cholesterol; FIP2000: focal adhesion kinase family interacting protein of 200kDa; FSH: follicle stimulating hormone; HDL: high-density lipoprotein; IVF: in vitro fertilization; LC3: microtubule-associated protein light chain 3; LD: lipid droplet; LH: luteinising hormone; MC-LR: microcystin-LR; MEFs: mouse embryonic fibroblast cells; MT: microtubule; mtDNA: mitochondrial DNA; mTOR: mammalian target of rapamycin; NHERF2: Na⁺/H⁺ exchanger regulatory factor 2; NMR: naked mole-rat; PCD: programmed cell death; PDLIM1: PDZ and LIM domain 1; PGCs: primordial germ cells; PGF_2α: prostaglandin F_2α; PI3K: phosphatidylinositol-3-kinase; PI3P: phosphatidylinositol-3-phosphate; ROS: reactive oxygen species; SCG10: superior cervical ganglia protein 10; SR-BI: scavenger receptor class B, type I; StAR protein: steroidogenic acute regulatory protein; TC: total cholesterol; TEM: transmission electron microscopy; TUNEL: terminal deoxynucleotidyl transferase mediated dUTP nick end labeling; ULK1: mammalian uncoordinated-51-like kinase 1; WIPI: WD-repeat domain phosphoinositide-interacting.

Myosin VIIa Supports Spermatid/Organelle Transport and Cell Adhesion During Spermatogenesis in the Rat Testis

The biology of transport of spermatids and spermatid adhesion across the seminiferous epithelium during the epithelial cycle remains largely unexplored. Nonetheless, studies have implicated the role of motor proteins in these cellular events. In this article, we report findings to unravel the role of myosin VIIa, an F-actin-based barbed (+)-end-directed motor protein, to support cellular transport and adhesion in the testis. Using RNA interference to knock down myosin VIIa in Sertoli cells cultured in vitro as a study model was shown to perturb the Sertoli cell tight junction permeability barrier, mediated through disorganization of actin- or microtubule (MT)-based cytoskeletons owing to disruptive changes on the spatiotemporal expression of F-actin or MT-regulatory proteins. Consistent with these in vitro findings, knockdown of myosin VIIa in the testis in vivo also induced disorganization of the actin- and MT-based cytoskeletons across the seminiferous epithelium, mediated by disruptive changes in the spatiotemporal expression of actin- and MT-based regulatory proteins. More important, the transport of spermatids and organelles across the epithelium, as well as cell adhesion, was grossly disrupted. For instance, step 19 spermatids failed to be transported to the adluminal compartment near the tubule lumen to undergo spermiation; in this manner, step 19 spermatids were persistently detected in stage IX and XII tubules, intermingling with step 9 and 12 spermatids, respectively. Also, phagosomes were detected near the tubule lumen in stage I to III tubules when they should have been degraded near the base of the seminiferous epithelium via the lysosomal pathway. In summary, myosin VIIa motor protein was crucial to support cellular transport and adhesion during spermatogenesis.

Planar cell polarity protein Dishevelled 3 (Dvl3) regulates ectoplasmic specialization (ES) dynamics in the testis through changes in cytoskeletal organization

In the mammalian testes, such as in rats, the directional alignment of polarized elongating/elongated spermatids, in particular step 17-19 spermatids, across the plane of seminiferous epithelium resembles planar cell polarity (PCP) found in hair cells of the cochlea. It is obvious that spermatid PCP is necessary to support the simultaneous development of maximal number of elongating/elongated spermatids to sustain the daily production of > 50 million sperm per adult rat. Studies have shown that the testis indeed expresses multiple PCP proteins necessary to support spermatid PCP. Herein, using physiological and biochemical assays, and morphological analysis, and with the technique of RNA interference (RNAi) to knockdown PCP protein Dishevelled (Dvl) 1 (Dvl1), Dvl2, Dvl3, or Dvl1/2/3, Dvl proteins, in particular Dvl3, it was shown that Dvl3 played a crucial role of support Sertoli cell tight junction (TJ)-permeability barrier function through changes in the organization of actin- and microtubule (MT)-based cytoskeletons. More important, an in vivo knockdown of Dvl1/2/3 in the testis, defects of spermatid polarity were remarkably noted across the seminiferous epithelium, concomitant with defects of spermatid adhesion and spermatid transport, leading to considerably defects in spermatogenesis. More important, Dvl1/2/3 triple knockdown in the testis also impeded the organization of actin- and MT-based cytoskeletons owing to disruptive spatial expression of actin- and MT-regulatory proteins. In summary, PCP Dishevelled proteins, in particular, Dvl3 is a regulator of Sertoli cell blood-testis barrier (BTB)  and also spermatid PCP function through its effects on the actin- and MT-based cytoskeletons in Sertoli cells.

Ethanol-Induced Autophagy in Sertoli Cells Is Specifically Marked at Androgen-Dependent Stages of the Spermatogenic Cycle: Potential Mechanisms and Implications

In a recent study, we reported that acute ethanol exposure enhanced autophagy in Sertoli cells (SCs) of adult rats. However, further research is needed to clarify the specific spermatogenic stage exhibiting the highest autophagic response, the mechanisms behind such specificity, and the related relevance to sperm. This brief report provides results indicating that stages VII⁻VIII (androgen-dependent or spermiation stages) of the spermatogenic cycle exhibited more marked autophagic response in acute-ethanol treated rats (ETRs) than other stages based on suppression of androgen receptor (AR), analysis of microtubule-associated protein 1 light chain 3 (LC3) (an autophagosomal marker) immunostaining in SCs, double labeling of LC3 and lysosomal proteins and electron microscopy. Ultrastructural observations and TUNEL method revealed a notable presence of phagocytosed apoptotic germ cells and retained sperm in SCs of ETRs at these specific stages-a finding rarely observed in control testes. In addition, PTEN-induced putative kinase 1 ( PINK1) (a sensor of mitochondrial damage and mitophagy) and giant lipid droplets were found to have accumulated in SCs of ETRs at same stages. Our data show novel findings indicating that stages VII⁻VIII of the spermatogenic cycle exhibit high levels of autophagy, specifically under stress conditions, as expressed by the term autophagic stages. This stage-specific upregulation of autophagy in SCs may be related to AR suppression, mitochondrial damage, lipid accumulation, and phagocytosis of apoptotic cells. The phenomenon may be an essential part of ensuring the viability of SCs and supporting germ cells in toxic environments.

Sulphur dioxide and arsenic affect male reproduction via interfering with spermatogenesis in mice

As two potential environmental hazards, sulphur dioxide (SO₂) and arsenic have adverse effects on male reproduction, but the mechanism of which and their combined toxicity are not clear. In this study, we investigate male reproductive toxicity with a focus on spermatogenesis by treating mice with 5 mg/m³ SO₂ and/or 5 mg/L arsenic. Our results showed that arsenic exposure caused significant decreases in water and food consumption and body weight in mice, whereas these changes were not observed in the SO₂-only group. Both SO₂ and arsenic reduced sperm counts, increased the percentage of sperm malformation, and induced abnormal testicular pathological changes. Elevated H₂O₂ and MDA contents, declined T-SOD activity, decreased spermatogenic cell counts, enhanced caspase-3 activity, and increased TUNEL-positive cells were also observed in mice exposed to SO₂ and/or arsenic. Moreover, SO₂ and arsenic co-exposure changed the mRNA levels of Bax and Bcl-2, decreased serum testosterone levels, and downregulated the expression of steroidogenic-related genes (LHR, StAR, and ABP) in mice. These findings provide a new theoretical basis for understanding how SO₂ and arsenic interfere with spermatogenesis leading to infertility. These results also suggest that SO₂ and arsenic co-exposure likely result in an additive effect on male reproductive toxicity in mice.

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.

miR-26a inhibits proliferation and promotes apoptosis in porcine immature Sertoli cells by targeting the PAK2 gene

Accumulating reports have demonstrated that microRNAs (miRNAs) participate in regulating the complex processes of animal testis development and spermatogenesis; yet, the mechanisms by which miRNAs regulate spermatogenesis are poorly understood. miR-26a was identified as a miRNA that is differentially expressed among different pig testicular tissue developmental stages in our previous study. In this study, p21 activated kinase 2 (PAK2) gene was determined as one target gene of miR-26a by luciferase reporter assay, and miR-26a repressed the PAK2 mRNA abundance in porcine Sertoli cells. The Cell Counting Kit-8 (CCK8) assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay and annexin V-FITC/PI staining assay results showed that miR-26a overexpression inhibited proliferation and promoted apoptosis in porcine Sertoli cells. These phenomena were similar to the siRNA-mediated knockdown of the PAK2 gene. Taken together, our results demonstrate that miR-26a inhibits proliferation and promotes apoptosis in porcine Sertoli cells by targeting the PAK2 gene, which may be a regulator of porcine spermatogenesis.